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Sample records for coatings sam hpcrm

  1. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO & DOE OCRWM Co-Sponsored Advanced Materials Program

    SciTech Connect

    Farmer, J; Haslam, J; Wong, F; Ji, S; Day, S; Branagan, D; Marshall, M; Meacham, B; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Weaver, D; Aprigliano, L; Kohler, L; Bayles, R; Lemieux, E; Wolejsza, T; Martin, F; Yang, N; Lucadamo, G; Perepezko, J; Hildal, K; Kaufman, L; Heuer, A; Ernst, F; Michal, G; Kahn, H; Lavernia, E

    2007-09-19

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent.

  2. Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Control

    SciTech Connect

    Choi, J

    2007-01-12

    This report describes the analysis and modeling approaches used in the evaluation for criticality-control applications of the neutron-absorbing structural-amorphous metal (SAM) coatings. The applications of boron-containing high-performance corrosion-resistant material (HPCRM)--amorphous metal as the neutron-absorbing coatings to the metallic support structure can enhance criticality safety controls for spent nuclear fuel in baskets inside storage containers, transportation casks, and disposal containers. The use of these advanced iron-based, corrosion-resistant materials to prevent nuclear criticality in transportation, aging, and disposal containers would be extremely beneficial to the nuclear waste management programs.

  3. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

    SciTech Connect

    Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

    2007-09-20

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  4. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings Evaluation of Corrosion Reistance FY05 HPCRM Annual Report # Rev. 1DOE-DARPA Co-Sponsored Advanced Materials Program

    SciTech Connect

    Farmer, J C; Haslam, J J; Day, S D

    2007-09-19

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  5. EFFECTS OF POLYCYCLIC AROMATIC HYDROCARBON OF SAM-COATED ELECTRODES USING FERRYICYANIDE AS THE REDOX INDICATOR

    EPA Science Inventory

    Electrochemical responses on self-assembled monolayer (SAM)-coated polycrystalline gold electrodes were investigated using cyclic voltammetry and square wave voltammetry with a three electrode system. Experimental results show potential in the application of pyrene-imprinted SAM...

  6. Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Controls

    SciTech Connect

    Choi, J; Lee, C; Day, D; Wall, M; Saw, C; MoberlyChan, W; Farmer, J; Boussoufl, M; Liu, B; Egbert, H; Branagan, D; D'Amato, A

    2006-11-13

    Spent nuclear fuel contains fissionable materials ({sup 235}U, {sup 239}Pu, {sup 241}Pu, etc.). Neutron multiplication and the potential for criticality are enhanced by the presence of a moderator during cask loading in water, water incursion in accidents conditions during spent fuel storage or transport. To prevent nuclear criticality in spent fuel storage, transportation, and during disposal, neutron-absorbing materials (or neutron poisons, such as borated stainless steel, Boral{trademark}, Metamic{trademark}, Ni-Gd, and others) would have to be applied. The success in demonstrating that the High-Performance Corrosion-Resistant material (HPCRM) can be thermally applied as coating onto base metal to provide for corrosion resistance for many naval applications raises the interest in applying the HPCRM to USDOE/OCRWM spent fuel management program. The fact that the HPCRM relies on the high content of boron to make the material amorphous--an essential property for corrosion resistance--and that the boron has to be homogeneously distributed in the HPCRM qualify the material to be a neutron poison.

  7. Iron-Based Amorphous-Metals: High-Performance Corrosion-Resistant Material (HPCRM) Development

    SciTech Connect

    Farmer, J C; Choi, J S; Saw, C; Haslam, J; Day, D; Hailey, P; Lian, T; Rebak, R; Perepezko, J; Payer, J; Branagan, D; Beardsley, B; D'Amato, A; Aprigliano, L

    2008-01-09

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional

  8. Iron-Based Amorphous Metals:The High Performance Corrosion Resistant Materials(HPCRM) Program

    SciTech Connect

    Farmer, J

    2007-07-09

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional

  9. Iron-Based Amorphous-Metals: High-Performance Corrosion-Resistant Materials (HPCRM) Development Final Report

    SciTech Connect

    Farmer, J C; Choi, J; Saw, C; Haslem, J; Day, D; Hailey, P; Lian, T; Rebak, R; Perepezko, J; Payer, J; Branagan, D; Beardsley, B; D'Amato, A; Aprigliano, L

    2009-03-16

    An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal make this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of these iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional

  10. SALT FOG TEST OF SAM2X5 COATED STAINLESS STEEL CYLINDER

    SciTech Connect

    Aprigliano, L F; Rebak, R B; Choi, J; Lian, T; Day, S D

    2007-04-23

    A salt fog test of an iron-based amorphous metal, SAM2X5, coated Type 316L stainless steel (SS316L) cylinder was made. The cylinder was 30-inch diameter by 88-inch long, and 3/8-inch thick. One end was welded shut with a SS316L end cap before coating. The body of the cylinder and the end cap were both coated. The cylinder was coated with SAM2X5 by the HVOF thermal spray process. The coating thickness was 0.015-inch to 0.019-inch thick. The cylinder was tested in a horizontal position. Also included in the test for reference purposes were five coupons (2-inch x 2-inch x 1/8-inch) of uncoated Type 1018 carbon steel (1018CS). The test used an abbreviated form of GM 9540P. Each cycle was 6 hours in duration and the cylinder and reference samples were exposed to a total of eight cycles. The cylinder was in relatively good condition after the test. Along the body of the cylinder only two pinpoint spot sized signs of rust were seen. The 1018CS reference specimens were extensively rusted.

  11. Atomistic characterization of SAM coatings as gate insulators in Si-based FET devices

    SciTech Connect

    Gala, F.; Zollo, G.

    2014-06-19

    Many nano-material systems are currently under consideration as possible candidates for gate dielectric insulators in both metal-oxide-semiconductor (MOSFET) and organic (OFET) field-effect transistors. In this contribution, the possibility of employing self-assembled monolayers (SAMs) of hydroxylated octadecyltrichlorosilane (OTS) chains on a (111) Si substrate as gate dielectrics is discussed; in particular ab initio theoretical simulations have been employed to study the structural properties, work function modifications, and the insulating properties of OTS thin film coatings on Si substrates.

  12. Absence of molecular slip on ultraclean and SAM-coated surfaces

    NASA Astrophysics Data System (ADS)

    Pye, Justin; Wood, Clay; Burton, Justin

    2016-11-01

    The liquid/solid boundary condition is a complex problem that is becoming increasingly important for the development of nanoscale fluidic devices. Many groups have now measured slip near an interface at nanoscale dimensions using a variety of experimental techniques. In simple systems, large slip lengths are generally measured for non-wetting liquid/solid combinations, but many conflicting measurements and interpretations remain. We have developed a novel pseudo-differential technique using a quartz crystal microbalance (QCM) to measure slip lengths on various surfaces. A drop of one liquid is grown on the QCM in the presence of a second, ambient liquid. We have isolated any anomalous boundary effects such as interfacial slip by choosing two liquids which have identical bulk effects on the QCM frequency and dissipation in the presence of no-slip. Slip lengths are -less than 2 nm- for water (relative to undecane) on all surfaces measured, including plasma cleaned gold, SiO2, and two different self assembled monolayers (SAMs), regardless of contact angle. We also find that surface cleanliness is crucial to accurately measure slip lengths. Additionally, clean glass substrates appear to have a significant adsorbed water layer and SAM surfaces show excess dissipation, possibly associated with contact line motion. In addition to investigating other liquid pairs, future work will include extending this technique to surfaces with independently controllable chemistry and roughness, both of which are known to strongly affect interfacial hydrodynamics.

  13. DOE-DARPA High-Performance Corrosion-Resistant Materials (HPCRM), Annual HPCRM Team Meeting & Technical Review

    SciTech Connect

    Farmer, J; Brown, B; Bayles, B; Lemieux, T; Choi, J; Ajdelsztajn, L; Dannenberg, J; Lavernia, E; Schoenung, J; Branagan, D; Blue, C; Peter, B; Beardsley, B; Graeve, O; Aprigliano, L; Yang, N; Perepezko, J; Hildal, K; Kaufman, L; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Lewandowski, J; Boudreau, J

    2007-09-21

    The overall goal is to develop high-performance corrosion-resistant iron-based amorphous-metal coatings for prolonged trouble-free use in very aggressive environments: seawater & hot geothermal brines. The specific technical objectives are: (1) Synthesize Fe-based amorphous-metal coating with corrosion resistance comparable/superior to Ni-based Alloy C-22; (2) Establish processing parameter windows for applying and controlling coating attributes (porosity, density, bonding); (3) Assess possible cost savings through substitution of Fe-based material for more expensive Ni-based Alloy C-22; (4) Demonstrate practical fabrication processes; (5) Produce quality materials and data with complete traceability for nuclear applications; and (6) Develop, validate and calibrate computational models to enable life prediction and process design.

  14. SAM in a Nutshell.

    ERIC Educational Resources Information Center

    Givens, Larry R.

    2000-01-01

    Explains what the Association of Higher Education Facilities Officers' Strategic Assessment Model (SAM) is and how to use it to achieve organizational excellence through continuous improvement. Showing features of both the Malcolm Baldrige programs and the Balanced Scorecard, the SAM components are described along with an explanation of the four…

  15. Heterotypic Sam-Sam association between Odin-Sam1 and Arap3-Sam: binding affinity and structural insights.

    PubMed

    Mercurio, Flavia A; Marasco, Daniela; Pirone, Luciano; Scognamiglio, Pasqualina L; Pedone, Emilia M; Pellecchia, Maurizio; Leone, Marilisa

    2013-01-02

    Arap3 is a phosphatidylinositol 3 kinase effector protein that plays a role as GTPase activator (GAP) for Arf6 and RhoA. Arap3 contains a sterile alpha motif (Sam) domain that has high sequence homology with the Sam domain of the EphA2-receptor (EphA2-Sam). Both Arap3-Sam and EphA2-Sam are able to associate with the Sam domain of the lipid phosphatase Ship2 (Ship2-Sam). Recently, we reported a novel interaction between the first Sam domain of Odin (Odin-Sam1), a protein belonging to the ANKS (ANKyrin repeat and Sam domain containing) family, and EphA2-Sam. In our latest work, we applied NMR spectroscopy, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) to characterize the association between Arap3-Sam and Odin-Sam1. We show that these two Sam domains interact with low micromolar affinity. Moreover, by means of molecular docking techniques, supported by NMR data, we demonstrate that Odin-Sam1 and Arap3-Sam might bind with a topology that is common to several Sam-Sam complexes. The revealed structural details form the basis for the design of potential peptide antagonists that could be used as chemical tools to investigate functional aspects related to heterotypic Arap3-Sam associations.

  16. Synthia Tonn, SAM Engineer

    NASA Video Gallery

    The Sample Analysis at Mars (SAM) is a suite of instruments developed for use on the Mars Science Laboratory, designed to help find out whether or not Mars ever supported life. This video profiles ...

  17. SAM Photovoltaic Model Technical Reference

    SciTech Connect

    Gilman, P.

    2015-05-27

    This manual describes the photovoltaic performance model in the System Advisor Model (SAM). The U.S. Department of Energy’s National Renewable Energy Laboratory maintains and distributes SAM, which is available as a free download from https://sam.nrel.gov. These descriptions are based on SAM 2015.1.30 (SSC 41).

  18. Adapting SAM for CDF

    SciTech Connect

    D. Bonham et al.

    2003-10-13

    The CDF and D0 experiments probe the high-energy frontier and as they do so have accumulated hundreds of Terabytes of data on the way to petabytes of data over the next two years. The experiments have made a commitment to use the developing Grid based on the SAM system to handle these data. The D0 SAM has been extended for use in CDF as common patterns of design emerged to meet the similar requirements of these experiments. The process by which the merger was achieved is explained with particular emphasis on lessons learned concerning the database design patterns plus realization of the use cases.

  19. Other Resources Related to SAM

    EPA Pesticide Factsheets

    Learn more about websites and information related to EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM), including key EPA collaborators, laboratories, and research centers.

  20. SAM Companion Documents and Sample Collection Procedures

    EPA Pesticide Factsheets

    SAM Companion Documents and Sample Collection Procedures provide information intended to complement the analytical methods listed in Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  1. Faces of Marshall: Sam Ortega

    NASA Video Gallery

    Several Marshall employees were interviewed as part of Marshall's 50th Anniversary activities. Engineer Sam Ortega tells his story of how he came to work as an engineer at Marshall and how sewing a...

  2. Sam's progress with learning mathematics.

    PubMed

    Haslam, Lynne

    2007-07-01

    Sam is 18 years old and has Down syndrome. He achieved a grade in the standard assessment of mathematics (GCSE) at 16 years of age. This paper describes the part played in his success in school by the Kumon method of teaching mathematics, identifies the benefits of the small steps and lots of practice built in to the method and illustrates the way Sam applied his Kumon learning in school.

  3. Substation alarm multiplexing system (SAMS)

    SciTech Connect

    ElBadaly, H.; Gaughan, J.; Ward, G.; Amengual, S.

    1996-03-01

    This paper describes an on going R&D project to develop, design, install, and assess the field performance of an advanced substation alarm system. SAMS provides a highly fault-tolerant system for the reporting of equipment alarms. SAMS separates and identifies each of the multiple alarm contacts, transmits an alarm condition over existing substation two-wire system, and displays the alarm source, and its associated technical information, on a touch-screen monitor inside the substation control room, and a remote central location and on a hand held terminal which may be carried anywhere within the substation. SAMS is currently installed at the Sherman Creek substation in the Bronx for the purpose of a three month field evaluation.

  4. SAM Overview: The Habitability of Mars

    NASA Video Gallery

    Featuring an interview with Paul Mahaffy, SAM's Principal Investigator, this video gives a general overview of SAM's mission aboard the Mars Science Laboratory, otherwise known as the Curiosity rover.

  5. Long-Term Corrosion Tests of Prototypical SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) Coatings

    SciTech Connect

    Farmer, J C; Choi, J S; Saw, C K; Rebak, R H; Day, S D; Lian, T; Hailey, P D; Payer, J H; Branagan, D J; Aprigliano, L F

    2007-05-10

    An iron-based amorphous metal with good corrosion resistance and a high absorption cross-section for thermal neutrons has been developed and is reported here. This amorphous alloy has the approximate formula Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4} and is known as SAM2X5. Chromium (Cr), molybdenum (Mo) and tungsten (W) were added to provide corrosion resistance, while boron (B) was added to promote glass formation and the absorption of thermal neutrons. Since this amorphous metal has a higher boron content than conventional borated stainless steels, it provides the nuclear engineer with design advantages for criticality control structures with enhanced safety. While melt-spun ribbons with limited practical applications were initially produced, large quantities (several tons) of gas atomized powder have now been produced on an industrial scale, and applied as thermal-spray coatings on prototypical half-scale spent nuclear fuel containers and neutron-absorbing baskets. These prototypes and other SAM2X5 samples have undergone a variety of corrosion testing, including both salt-fog and long-term immersion testing. The modes and rates of corrosion have been determined in the various environments, and are reported here. While these coatings have less corrosion resistance than melt-spun ribbons and optimized coatings produced in the laboratory, substantial corrosion resistance has been achieved.

  6. Laser Induced Temperature Field on Surfaces: Application to SAM Patterning

    NASA Astrophysics Data System (ADS)

    Shadnam, Mohammad Reza; Amirfazli, Alidad

    2004-03-01

    Laser is used to thermally desorb a self assembeled monolayer (SAM) from a gold substrate. This process is a key step in making patterned surfaces. In many applications making curvilinear features is useful. Heating of a surface by a CW laser along a nonlinear trajectory is considered using Green's functions. Temperature profiles are calculated for heating along circular-arc trajectories of different curvatures. The effect of heating trajectory's radius of curvature and heating spot's velocity (Laser scanning rate) on resulting surface temperature is studied. It is shown that within the range of parameters considered, the induced surface temperature profiles are symmetric. It is also shown that change of heating trajectory's radius of curvature by one order of magnitude at heating velocity of 0.1 mm/s changes the induced surface temperatures by 12 K; this temperature increase will be 36 K at 1 mm/s. The effect of such temperature increases are discussed in terms of laser processing of SAM coated surfaces. For a case of heating along straight line, the kinetics of SAM desorption is coupled with heat diffusion equation to predict the percentage of SAM desorped and determine the feature size. The resulting surface chemical composition profiles are compared with experimental measurements and good agreement is reported.

  7. SAMS Acceleration Measurements on MIR

    NASA Technical Reports Server (NTRS)

    Moskowitz, Milton E.; Hrovat, Kenneth; Finkelstein, Robert; Reckart, Timothy

    1997-01-01

    During NASA Increment 3 (September 1996 to January 1997), about 5 gigabytes of acceleration data were collected by the Space Acceleration Measurement System (SAMS) onboard the Russian Space Station, Mir. The data were recorded on 11 optical disks and were returned to Earth on STS-81. During this time, SAMS data were collected in the Priroda module to support the following experiments: the Mir Structural Dynamics Experiment (MiSDE) and Binary Colloidal Alloy Tests (BCAT). This report points out some of the salient features of the microgravity environment to which these experiments were exposed. Also documented are mission events of interest such as the docked phase of STS-81 operations, a Progress engine burn, attitude control thruster operation, and crew exercise. Also included are a description of the Mir module orientations, and the panel notations within the modules. This report presents an overview of the SAMS acceleration measurements recorded by 10 Hz and 100 Hz sensor heads. Variations in the acceleration environment caused by unique activities such as crew exercise and life-support fans are presented. The analyses included herein complement those presented in previous mission summary reports published by the Principal Investigator Microgravity Services (PIMS) group.

  8. Selective Plasma Deposition of Fluorocarbon Films on SAMs

    NASA Technical Reports Server (NTRS)

    Crain, Mark M., III; Walsh, Kevin M.; Cohn, Robert W.

    2006-01-01

    A dry plasma process has been demonstrated to be useful for the selective modification of self-assembled monolayers (SAMs) of alkanethiolates. These SAMs are used, during the fabrication of semiconductor electronic devices, as etch masks on gold layers that are destined to be patterned and incorporated into the devices. The selective modification involves the formation of fluorocarbon films that render the SAMs more effective in protecting the masked areas of the gold against etching by a potassium iodide (KI) solution. This modification can be utilized, not only in the fabrication of single electronic devices but also in the fabrication of integrated circuits, microelectromechanical systems, and circuit boards. In the steps that precede the dry plasma process, a silicon mold in the desired pattern is fabricated by standard photolithographic techniques. A stamp is then made by casting polydimethylsiloxane (commonly known as silicone rubber) in the mold. The stamp is coated with an alkanethiol solution, then the stamp is pressed on the gold layer of a device to be fabricated in order to deposit the alkanethiol to form an alkanethiolate SAM in the desired pattern (see figure). Next, the workpiece is exposed to a radio-frequency plasma generated from a mixture of CF4 and H2 gases. After this plasma treatment, the SAM is found to be modified, while the exposed areas of gold remain unchanged. This dry plasma process offers the potential for forming masks superior to those formed in a prior wet etching process. Among the advantages over the wet etching process are greater selectivity, fewer pin holes in the masks, and less nonuniformity of the masks. The fluorocarbon films formed in this way may also be useful as intermediate layers for subsequent fabrication steps and as dielectric layers to be incorporated into finished products.

  9. Sam.

    ERIC Educational Resources Information Center

    Wilson, James C.

    1988-01-01

    A father writes about his six-year-old son born with hydrocephalus. He describes such day-to-day experiences as going to a baseball game and the grocery store, reactions of friends and strangers to his son's social interactions, and a special day at preschool. The boy's medical treatment, including surgeries, are also described. (VW)

  10. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  11. 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

  12. SAM 2 balloon test (stratospheric aerosol measurement)

    NASA Technical Reports Server (NTRS)

    Pepin, T. J.

    1976-01-01

    As a parallel effort to the LACATE balloon experiment a small optical system was constructed to enable a balloon test of a diode filter system similar to the type planned for the Nimbus-G SAM II experiment. The system was called the SAM II Balloon Test. Results of the balloon flight are summarized.

  13. Patterning NHS-terminated SAMs on germanium.

    PubMed

    Morris, Carleen J; Shestopalov, Alexander A; Gold, Brian H; Clark, Robert L; Toone, Eric J

    2011-05-17

    Here we report a simple, robust approach to patterning functional SAMs on germanium. The protocol relies on catalytic soft-lithographic pattern transfer from an elastomeric stamp bearing pendant immobilized sulfonic acid moieties to an NHS-functionalized bilayer molecular system comprising a primary ordered alkyl monolayer and a reactive ester secondary overlayer. The catalytic polyurethane-acrylate stamp was used to form micrometer-scale features of chemically distinct SAMs on germanium. The methodology represents the first example of patterned SAMs on germanium, a semiconductor material.

  14. STS-134 Crew Talks With Sam Ting

    NASA Video Gallery

    The STS-134 crew talks with Sam Ting, principal investigator for the Alpha Magnetic Spectrometer, following the installation of the particle physics detector on the International Space Station duri...

  15. NES Live Video Chat: Engineer Sam Ortega

    NASA Video Gallery

    The NES project invited all K-12 students to participate in a one-hour-long NASA video webchat on April 19, 2011 with NASA engineer Sam Ortega. Ortega answered questions about building and testing ...

  16. Quality Control Guidelines for SAM Radiochemical Methods

    EPA Pesticide Factsheets

    Learn more about quality control guidelines and recommendations for the analysis of samples using the radiochemistry methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  17. Quality Control Guidelines for SAM Biotoxin Methods

    EPA Pesticide Factsheets

    Learn more about quality control guidelines and recommendations for the analysis of samples using the pathogen methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  18. Quality Control Guidelines for SAM Pathogen Methods

    EPA Pesticide Factsheets

    Learn more about quality control guidelines and recommendations for the analysis of samples using the biotoxin methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  19. Quality Control Guidelines for SAM Chemical Methods

    EPA Pesticide Factsheets

    Learn more about quality control guidelines and recommendations for the analysis of samples using the chemistry methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  20. Drug delivery from therapeutic self-assembled monolayers (T-SAMs) on 316L stainless steel.

    PubMed

    Mahapatro, Anil; Johnson, Dave M; Patel, Devang N; Feldman, Marc D; Ayon, Arturo A; Agrawal, C Mauli

    2008-01-01

    Delivery of therapeutic agents from self-assembled monolayers (SAMs) on 316L stainless steel (SS) has been demonstrated as a viable method to deliver drugs for localized coronary artery stent application. SAMs are highly-ordered, nano-sized molecular coatings, adding 1-10 nm thickness to a surface. Hydroxyl terminated alkanethiol SAMs of 11-mercapto-1-undecanol (-OH SAM) were formed on 316L SS with 48 hr immersion in ethanolic solutions. Attachment of ibuprofen (a model drug) to the functional SAMs was carried out in toluene for 5 hrs at 60 degrees C using Novozume-435 as a biocatalyst. SAM formation and subsequent attachment of ibuprofen was characterized collectively using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and contact angle (CA) measure-ments. The quantitative in vitro release of ibuprofen into a "physiological" buffer solution was characterized using reverse phase HPLC. Drug release kinetics showed that 14.1 microg of ibuprofen eluted over a period of 35 days with 2.7microg being eluted in the first day and the remaining being eluted over a period of 35 days. The drug release kinetics showed an increase in ibuprofen elution that occurred during first 14 days (2.7microg in 1 day to 9.5 microg in 14 days), following which there was a decrease in the rate of elution. Thus, functional SAMs on 316L SS could be used as tethers for drug attachment and could serve as a drug delivery mechanism from stainless steel implants such as coronary artery stents.

  1. Sam, Brookhaven, and the Physical Review

    NASA Astrophysics Data System (ADS)

    Blume, Martin

    2010-03-01

    Sam Goudsmit came to Brookhaven National Laboratory in 1948, just after the first year of operation of the new institution, and after a year of his postwar appointment as Professor of Physics at Northwestern University. He was named an associate editor of the Physical Review at that time, under the then Managing Editor John T. Tate of the University of Minnesota. Tate had been Editor since 1926, and had presided over the growth of Physical Review to leadership of publication in the world of physics. Tate died in 1950, and after a search under an interim Editor Sam was, in 1951, named Managing Editor. In 1952 he became Chair of the Brookhaven Physics Department, founded Physical Review Letters, and served as department chair until 1960, when he stepped down but remained an Associate Chair. I will discuss my own interactions with Sam during this later period, when I learned of his many faceted talents and accomplishments.

  2. Validation of SAM 2 and SAGE satellite

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Wang, P.-H.; Farrukh, U. O.; Yue, G. K.

    1987-01-01

    Presented are the results of a validation study of data obtained by the Stratospheric Aerosol and Gas Experiment I (SAGE I) and Stratospheric Aerosol Measurement II (SAM II) satellite experiments. The study includes the entire SAGE I data set (February 1979 - November 1981) and the first four and one-half years of SAM II data (October 1978 - February 1983). These data sets have been validated by their use in the analysis of dynamical, physical and chemical processes in the stratosphere. They have been compared with other existing data sets and the SAGE I and SAM II data sets intercompared where possible. The study has shown the data to be of great value in the study of the climatological behavior of stratospheric aerosols and ozone. Several scientific publications and user-oriented data summaries have appeared as a result of the work carried out under this contract.

  3. Essay: Physical Review Letters; Sam Goudsmit's Vision.

    PubMed

    Adair, Robert K

    2008-01-18

    Sam Goudsmit implemented his vision of converting the Letters section of Physical Review into a distinct journal fifty years ago. Physical Review Letters was designed to publish "only papers that really deserve rapid communication." The new journal became so successful with physicists throughout the world that Physical Review Letters now publishes 3500 Letters per year.

  4. Sam's Journey to "Reach for the Stars"

    ERIC Educational Resources Information Center

    Mayer, Sue

    2007-01-01

    In this article, the author shares her experiences as a parent of a child with Down syndrome. Although her son Sam's first years were filled with numerous hospitalizations and visits to pediatricians, which she feared would further delay his development, she soon discovered an organization known as the National Association of Child Development…

  5. Structural Basis for Methyl Transfer by a Radical SAM Enzyme

    SciTech Connect

    Boal, Amie K.; Grove, Tyler L.; McLaughlin, Monica I.; Yennawar, Neela H.; Booker, Squire J.; Rosenzweig, Amy C.

    2014-10-02

    The radical S-adenosyl-l-methionine (SAM) enzymes RlmN and Cfr methylate 23S ribosomal RNA, modifying the C2 or C8 position of adenosine 2503. The methyl groups are installed by a two-step sequence involving initial methylation of a conserved Cys residue (RlmN Cys{sup 355}) by SAM. Methyl transfer to the substrate requires reductive cleavage of a second equivalent of SAM. Crystal structures of RlmN and RlmN with SAM show that a single molecule of SAM coordinates the [4Fe-4S] cluster. Residue Cys{sup 355} is S-methylated and located proximal to the SAM methyl group, suggesting the SAM that is involved in the initial methyl transfer binds at the same site. Thus, RlmN accomplishes its complex reaction with structural economy, harnessing the two most important reactivities of SAM within a single site.

  6. Selected Analytical Methods for Environmental Remediation and Recovery (SAM) - Home

    EPA Pesticide Factsheets

    The SAM Home page provides access to all information provided in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM), and includes a query function allowing users to search methods by analyte, sample type and instrumentation.

  7. Expanding Radical SAM Chemistry by Using Radical Addition Reactions and SAM Analogues.

    PubMed

    Ji, Xinjian; Li, Yongzhen; Xie, Liqi; Lu, Haojie; Ding, Wei; Zhang, Qi

    2016-09-19

    Radical S-adenosyl-l-methionine (SAM) enzymes utilize a [4Fe-4S] cluster to bind SAM and reductively cleave its carbon-sulfur bond to produce a highly reactive 5'-deoxyadenosyl (dAdo) radical. In almost all cases, the dAdo radical abstracts a hydrogen atom from the substrates or from enzymes, thereby initiating a highly diverse array of reactions. Herein, we report a change of the dAdo radical-based chemistry from hydrogen abstraction to radical addition in the reaction of the radical SAM enzyme NosL. This change was achieved by using a substrate analogue containing an olefin moiety. We also showed that two SAM analogues containing different nucleoside functionalities initiate the radical-based reactions with high efficiencies. The radical adduct with the olefin produced in the reaction was found to undergo two divergent reactions, and the mechanistic insights into this process were investigated in detail. Our study demonstrates a promising strategy in expanding radical SAM chemistry, providing an effective way to access nucleoside-containing compounds by using radical SAM-dependent reactions.

  8. On LAM's and SAM's for Halley's rotation

    NASA Technical Reports Server (NTRS)

    Peale, Stanton J.

    1992-01-01

    Non principal axis rotation for comet Halley is inferred from dual periodicities evident in the observations. The modes where the spin axis precesses around the axis of minimum moment of inertia (long axis mode or LAM) and where it precesses around the axis of maximum moment of inertia (short axis mode or SAM) are described from an inertial point of view. The currently favored LAM model for Halley's rotation state satisfies observational and dynamical constraints that apparently no SAM can satisfy. But it cannot reproduce the observed post perihelion brightening through seasonal illumination of localized sources on the nucleus, whereas a SAM can easily produce post or pre perihelion brightening by this mechanism. However, the likelihood of a LAM rotation for elongated nuclei of periodic comets such as Halley together with Halley's extreme post perihelion behavior far from the Sun suggest that Halley's post perihelion brightening may be due to effects other than seasonal illumination of localized sources, and therefore such brightening may not constrain its rotation state.

  9. System Advisor Model, SAM 2014.1.14: General Description

    SciTech Connect

    Blair, N.; Dobos, A. P.; Freeman, J.; Neises, T.; Wagner, M.; Ferguson, T.; Gilman, P.; Janzou, S.

    2014-02-01

    This document describes the capabilities of the U.S. Department of Energy and National Renewable Energy Laboratory's System Advisor Model (SAM), Version 2013.9.20, released on September 9, 2013. SAM is a computer model that calculates performance and financial metrics of renewable energy systems. Project developers, policy makers, equipment manufacturers, and researchers use graphs and tables of SAM results in the process of evaluating financial, technology, and incentive options for renewable energy projects. SAM simulates the performance of photovoltaic, concentrating solar power, solar water heating, wind, geothermal, biomass, and conventional power systems. The financial model can represent financial structures for projects that either buy and sell electricity at retail rates (residential and commercial) or sell electricity at a price determined in a power purchase agreement (utility). SAM's advanced simulation options facilitate parametric and sensitivity analyses, and statistical analysis capabilities are available for Monte Carlo simulation and weather variability (P50/P90) studies. SAM can also read input variables from Microsoft Excel worksheets. For software developers, the SAM software development kit (SDK) makes it possible to use SAM simulation modules in their applications written in C/C++, C#, Java, Python, and MATLAB. NREL provides both SAM and the SDK as free downloads at http://sam.nrel.gov. Technical support and more information about the software are available on the website.

  10. Peptide Fragments of Odin-Sam1: Conformational Analysis and Interaction Studies with EphA2-Sam.

    PubMed

    Mercurio, Flavia A; Di Natale, Concetta; Pirone, Luciano; Scognamiglio, Pasqualina L; Marasco, Daniela; Pedone, Emilia M; Saviano, Michele; Leone, Marilisa

    2015-07-27

    Odin is a protein belonging to the ANKS family, and has two tandem Sam domains. The first, Odin-Sam1, binds to the Sam domain of the EphA2 receptor (EphA2-Sam); this interaction could be crucial for the regulation of receptor endocytosis and might have an impact on cancer. Odin-Sam1 associates with EphA2-Sam by adopting a "mid-loop/end-helix" model. In this study three peptide sequences, encompassing the mid-loop interacting portion of Odin-Sam1 and its C-terminal α5 helix, were designed. Their conformational properties were analyzed by CD and NMR. In addition, their abilities to interact with EphA2-Sam were investigated by SPR studies. The peptides adopt a predominantly disordered state in aqueous buffer, but a higher helical content is evident in the presence of the cosolvent trifluoroethanol. Dissociation constants towards EphA2-Sam were in the high micromolar range. The structural findings suggest further routes for the design of potential anti-cancer therapeutics as inhibitors of EphA2-Sam heterotypic interactions.

  11. SOAR Adaptive Module (SAM): Seeing Improvement with a UV Laser

    NASA Astrophysics Data System (ADS)

    Tokovinin, Andrei; Cantarutti, Rolando; Tighe, Roberto; Schurter, Patricio; Martinez, Manuel; Thomas, Sandrine; van der Bliek, Nicole

    2016-12-01

    The adaptive module of the 4.1 m SOAR telescope, SOAR Adaptive Module (SAM), corrects ground-layer turbulence using an ultraviolet laser guide star. It has been commissioned in 2013 and it is in regular science operation since 2014. SAM works with the CCD imager covering a 3‧ field or with the speckle camera. It operates routinely and stably, delivering resolution in the I band equal to the free-atmosphere seeing. This paper describes the SAM system as a whole, providing essential reference for its users and technical information of interest to instrumentalists. Operation of the instrument, its performance, and science projects done with SAM so far are reviewed.

  12. General Quality Control (QC) Guidelines for SAM Methods

    EPA Pesticide Factsheets

    Learn more about quality control guidelines and recommendations for the analysis of samples using the methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  13. Low temperature solution deposition of calcium phosphate coatings for orthopedic implants

    SciTech Connect

    Campbell, A.A.; Graff, G.L.

    1994-04-01

    Calcium phosphate coatings were grown from aqueous solution onto a derivatized self-assmebled monolayer (SAM) which was covalently bound to a titanium metal substrate. The SAM molecules provided an idea connection between the metal surface and the calcium phosphate coating. The trichlorosilane terminus of the SAM molecule insured covalent attachment to the surface, while the functionalized ``tail`` induced heterogeneous nucleation of the calcium phosphate coating from supersaturated solutions. This low temperature process allowed for uniform coatings to be produced onto complex-shaped and/or microporous surfaces and provided better control of phase purity.

  14. Theodore Roosevelt Chloroforming Uncle Sam "In the Hopeless Ward".

    PubMed

    Drew, Benjamin A; Bause, George S

    2016-10-01

    In March of 1905 in Judge magazine, Louis Dalrymple published his political cartoon of Theodore Roosevelt chloroforming "Uncle Sam." Having sampled a host of Democratic remedies, the 125-year-old Sam can expect that Roosevelt's chloroform will either cure him with major Republican surgery or kill him with Osler-linked euthanasia.

  15. Student Activities in Meteorology (SAM), June 1994

    SciTech Connect

    Meier, B.L.; Passarelli, E.

    1994-06-01

    In an effort to inspire student interest in science and technology, scientists from the Forecast Systems Laboratory, a laboratory within the National Oceanic and Atmospheric Administration's (NOAA) Environmental Research Laboratories, and classroom teachers from the Boulder Valley School District collaborated to produce a series of classroom science activities on meteorology and atmospheric science. We call this series 'Student Activities in Meteorology,' or SAM. The goal is to provide activities that are interesting to students, and at the same time convenient and easy to use for teachers. The activity topics chosen are to incorporate trend setting scientific research and cutting edge technology. Several of the activities focus on the meteorological concerns of the Denver metropolitan area because many of NOAA's research labs are located in Boulder, where much of the research and testing for the region is performed. We believe that these activities are versatile and can be easily integrated into current science, environmental studies, health, social studies, and math curricula.

  16. Iron-Based Amorphous Coatings Produced by HVOF Thermal Spray Processing-Coating Structure and Properties

    SciTech Connect

    Beardsley, M B

    2008-03-26

    The feasibility to coat large SNF/HLW containers with a structurally amorphous material (SAM) was demonstrated on sub-scale models fabricated from Type 316L stainless steel. The sub-scale model were coated with SAM 1651 material using kerosene high velocity oxygen fuel (HVOF) torch to thicknesses ranging from 1 mm to 2 mm. The process parameters such as standoff distance, oxygen flow, and kerosene flow, were optimized in order to improve the corrosion properties of the coatings. Testing in an electrochemical cell and long-term exposure to a salt spray environment were used to guide the selection of process parameters.

  17. System Advisor Model, SAM 2011.12.2: General Description

    SciTech Connect

    Gilman, P.; Dobos, A.

    2012-02-01

    This document describes the capabilities of the U.S. Department of Energy and National Renewable Energy Laboratory's System Advisor Model (SAM), Version 2011.12.2, released on December 2, 2011. SAM is software that models the cost and performance of renewable energy systems. Project developers, policy makers, equipment manufacturers, and researchers use graphs and tables of SAM results in the process of evaluating financial, technology, and incentive options for renewable energy projects. SAM simulates the performance of solar, wind, geothermal, biomass, and conventional power systems. The financial model can represent financing structures for projects that either buy and sell electricity at retail rates (residential and commercial) or sell electricity at a price determined in a power purchase agreement (utility). Advanced analysis options facilitate parametric, sensitivity, and statistical analyses, and allow for interfacing SAM with Microsoft Excel or with other computer programs. SAM is available as a free download at http://sam.nrel.gov. Technical support and more information about the software are available on the website.

  18. SAM 2 and SAGE data management and processing

    NASA Technical Reports Server (NTRS)

    Osborn, M. T.; Trepte, C. R.

    1987-01-01

    The data management and processing supplied by ST Systems Corporation (STX) for the Stratospheric Aerosol Measurement 2 (SAM 2) and Stratospheric Aerosol and Gas Experiment (SAGE) experiments for the years 1983 to 1986 are described. Included are discussions of data validation, documentation, and scientific analysis, as well as the archival schedule met by the operational reduction of SAM 2 and SAGE data. Work under this contract resulted in the archiving of the first seven years of SAM 2 data and all three years of SAGE data. A list of publications and presentations supported was also included.

  19. Cooperative binding of TIA-1 and U1 snRNP in K-SAM exon splicing activation

    SciTech Connect

    Gesnel, Marie-Claude; Theoleyre, Sandrine; Del Gatto-Konczak, Fabienne; Breathnach, Richard . E-mail: breathna@nantes.inserm.fr

    2007-07-13

    In 293 cells, splicing of the human fibroblast growth factor receptor-2 K-SAM alternative exon is inefficient, but can be made efficient by provoking TIA-1 binding to the U-rich IAS1 sequence downstream from the exon's 5' splice site. We show here that TIA-1 domains known to interact with U1 snRNP and to recruit it to 5' splice sites in vitro are required for TIA-1 activation of K-SAM exon splicing in vivo. We further show that tethering downstream from the K-SAM exon a fusion between the U1 snRNP component U1C and the bacteriophage MS2 coat protein provokes IAS1-dependent exon splicing, and present evidence that the fusion functions after its incorporation into U1 snRNP. Our in vivo data, taken together with previous in vitro results, show that K-SAM splicing activation involves cooperative binding of TIA-1 and U1 snRNP to the exon's 5' splice site region.

  20. SAM Chlorine Observations at Gale Crater

    NASA Astrophysics Data System (ADS)

    Conrad, P. G.; Farley, K. A.; Vasconcelos, P. M.; Malespin, C.; Franz, H.; McAdam, A.; Sutter, B.; Stern, J. C.; Clark, B. C.; Atreya, S. K.; Mahaffy, P. R.; Martín-Torres, J.; Zorzano, M. P.

    2014-12-01

    The Sample Analysis at Mars investigation has detected Cl-bearing phases of various oxidation states in its thermally evolved gas measurements of both a wind drift deposit of fines and three different rock samples delivered as sieved drill powders to the instrument suite. In addition to HCl (Leshin et al, 2013; Ming et al, 2013) and chlorinated hydrocarbon detections (Glavin et al, 2013; Freissinet et al, in review), oxygen releases consistent with the decomposition of perchlorate salts are also observed. We have also measured chlorine isotope ratios of the four different solid samples, which yielded variable and more negative δ37Cl than typically observed in SNC meteorite analyses. We summarize our chlorine observations in the context of other gases observed in the SAM solid sample analyses, including water, sulfur- and nitrogen-bearing compounds, and REMS observations of Relative Humidity and Temperature, and compare with knowledge of martian chlorine obtained from the SNC meteorites. Finally, we examine the implications of surface/atmosphere Cl interactions and isotopic ratios for the rise and decline of habitable surface environments on Mars. This research was supported by the National Aeronautics and Space Administration (NASA) Mars Science Laboratory mission.

  1. Crystal structures of the SAM-III/S[subscript MK] riboswitch reveal the SAM-dependent translation inhibition mechanism

    SciTech Connect

    Lu, C.; Smith, A.M.; Fuchs, R.T.; Ding, F.; Rajashankar, K.; Henkin, T.M.; Ke, A.

    2010-01-07

    Three distinct classes of S-adenosyl-L-methionine (SAM)-responsive riboswitches have been identified that regulate bacterial gene expression at the levels of transcription attenuation or translation inhibition. The SMK box (SAM-III) translational riboswitch has been identified in the SAM synthetase gene in members of the Lactobacillales. Here we report the 2.2-{angstrom} crystal structure of the Enterococcus faecalis SMK box riboswitch. The Y-shaped riboswitch organizes its conserved nucleotides around a three-way junction for SAM recognition. The Shine-Dalgarno sequence, which is sequestered by base-pairing with the anti-Shine-Dalgarno sequence in response to SAM binding, also directly participates in SAM recognition. The riboswitch makes extensive interactions with the adenosine and sulfonium moieties of SAM but does not appear to recognize the tail of the methionine moiety. We captured a structural snapshot of the SMK box riboswitch sampling the near-cognate ligand S-adenosyl-L-homocysteine (SAH) in which SAH was found to adopt an alternative conformation and fails to make several key interactions.

  2. Technical Manual for the SAM Physical Trough Model

    SciTech Connect

    Wagner, M. J.; Gilman, P.

    2011-06-01

    NREL, in conjunction with Sandia National Lab and the U.S Department of Energy, developed the System Advisor Model (SAM) analysis tool for renewable energy system performance and economic analysis. This paper documents the technical background and engineering formulation for one of SAM's two parabolic trough system models in SAM. The Physical Trough model calculates performance relationships based on physical first principles where possible, allowing the modeler to predict electricity production for a wider range of component geometries than is possible in the Empirical Trough model. This document describes the major parabolic trough plant subsystems in detail including the solar field, power block, thermal storage, piping, auxiliary heating, and control systems. This model makes use of both existing subsystem performance modeling approaches, and new approaches developed specifically for SAM.

  3. Curiosity Shakes, Bakes, and Tastes Mars with SAM

    NASA Video Gallery

    NASA's Curiosity rover analyzed its first solid sample of Mars with a variety of instruments, including the Sample Analysis at Mars (SAM) instrument suite. Developed at NASA's Goddard Space Flight ...

  4. In-Orbit Calibration of a SAMS Triaxial Sensor Head

    NASA Technical Reports Server (NTRS)

    Chestney, Louis S.; Sicker, Ronald J.

    1996-01-01

    This report describes the results of in orbit calibration data collected for a Space Acceleration Measurement System (SAMS) Triaxial Sensor Head (TS H) and the methods used to process the data for bias and gravity levels.

  5. General Safety and Waste Management Related to SAM

    EPA Pesticide Factsheets

    The General Safety and Waste Management page offers section-specific safety and waste management details for chemicals, radiochemicals, pathogens, and biotoxins included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  6. Safety and Waste Management for SAM Chemistry Methods

    EPA Pesticide Factsheets

    The General Safety and Waste Management page offers section-specific safety and waste management details for the chemical analytes included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  7. Safety and Waste Management for SAM Radiochemical Methods

    EPA Pesticide Factsheets

    The General Safety and Waste Management page offers section-specific safety and waste management details for the radiochemical analytes included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  8. Safety and Waste Management for SAM Pathogen Methods

    EPA Pesticide Factsheets

    The General Safety and Waste Management page offers section-specific safety and waste management details for the pathogens included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  9. Rio Hondo Sediment Assessment Analysis Using SAM. Numerical Model Investigation

    DTIC Science & Technology

    1991-05-01

    MISCELLANEOUS PAPER HL-91-1 M ~ RIO HONDO SEDIMENT ASSESSMENT ANALYSIS USING SAM Numerical Model Investigation AD-A238 572Ii 1 11byIll lil Nolan K...FUNDING NUMBERS Rio Hondo Sediment Assessment Analysis Using SAM; Numerical Model Investigation 6. AUTHOR(S) Nolan K. Raphelt Michael J. Trawle William A... Rio Hondo through Roswell, NM, was conducted. The investigation represented a sediment assessment level study conducted to test for potential

  10. Molecular simulations of mixed self-assembled monolayer coated gold nanoparticles in water.

    PubMed

    J, Meena Devi

    2015-06-01

    Molecular dynamics simulations have been employed to study the hydration of a series of nanoparticles, each of which was coated with a mixed self-assembled monolayer (SAM) comprising methyl- and hydroxy-terminated alkane thiol chains. The mixing ratio of those chains are different for each nanoparticle. The simulations focused on the wetting behavior of the SAM-coated gold nanoparticles and the distribution and structure of their interfacial water molecules. The interactions of the mixed SAM-coated gold nanoparticles with water were analyzed by evaluating the radial distribution function, hydrogen bonds, the dipole orientations of the water molecules, and the water residence time in the interfacial region. The wettability of the mixed SAM-coated gold nanoparticles improved as the concentration of terminal hydroxy moieties was increased. The distribution and dynamics of the interfacial water molecules were found to be influenced by the mixing ratio of the terminal moieties of the SAM chains. The results of our simulations suggest that the surface interactions of the mixed SAM-coated gold nanoparticles with the aqueous medium can be modulated by systematically altering the mixing ratio of the terminal methyl and hydroxy moieties. This work may lead to new biological and technological applications and inspire the development of novel biomimetic materials. Graphical Abstract Mixed SAM-coated gold nanoparticles.

  11. SAMS Acceleration Measurements on Mir from June to November 1995

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard; Hrovat, Ken; Moskowitz, Milton; McPherson, Kevin

    1996-01-01

    The NASA Microgravity Science and Applications Division (MSAD) sponsors science experiments on a variety of microgravity carriers, including sounding rockets, drop towers, parabolic aircraft, and Orbiter missions. The MSAD sponsors the Space Acceleration Measurement System (SAMS) to support microgravity science experiments with acceleration measurements to characterize the microgravity environment to which the experiments were exposed. The Principal Investigator Microgravity Services project at the NASA Lewis Research Center supports principal investigators of microgravity experiments as they evaluate the effects of varying acceleration levels on their experiments. In 1993, a cooperative effort was started between the United States and Russia involving science utilization of the Russian Mir space station by scientists from the United States and Russia. MSAD is currently sponsoring science experiments participating in the Shuttle-Mir Science Program in cooperation with the Russians on the Mir space station. Included in the complement of MSAD experiments and equipment is a SAMS unit In a manner similar to Orbiter mission support, the SAMS unit supports science experiments from the U.S. and Russia by measuring the microgravity environment during experiment operations. The initial SAMS supported experiment was a Protein Crystal Growth (PCG) experiment from June to November 1995. SAMS data were obtained during the PCG operations on Mir in accordance with the PCG Principal Investigator's requirements. This report presents an overview of the SAMS data recorded to support this PCG experiment. The report contains plots of the SAMS 100 Hz sensor head data as an overview of the microgravity environment, including the STS-74 Shuttle-Mir docking.

  12. SAM68: Signal Transduction and RNA Metabolism in Human Cancer

    PubMed Central

    Frisone, Paola; Pradella, Davide; Di Matteo, Anna; Belloni, Elisa; Ghigna, Claudia; Paronetto, Maria Paola

    2015-01-01

    Alterations in expression and/or activity of splicing factors as well as mutations in cis-acting splicing regulatory sequences contribute to cancer phenotypes. Genome-wide studies have revealed more than 15,000 tumor-associated splice variants derived from genes involved in almost every aspect of cancer cell biology, including proliferation, differentiation, cell cycle control, metabolism, apoptosis, motility, invasion, and angiogenesis. In the past decades, several RNA binding proteins (RBPs) have been implicated in tumorigenesis. SAM68 (SRC associated in mitosis of 68 kDa) belongs to the STAR (signal transduction and activation of RNA metabolism) family of RBPs. SAM68 is involved in several steps of mRNA metabolism, from transcription to alternative splicing and then to nuclear export. Moreover, SAM68 participates in signaling pathways associated with cell response to stimuli, cell cycle transitions, and viral infections. Recent evidence has linked this RBP to the onset and progression of different tumors, highlighting misregulation of SAM68-regulated splicing events as a key step in neoplastic transformation and tumor progression. Here we review recent studies on the role of SAM68 in splicing regulation and we discuss its contribution to aberrant pre-mRNA processing in cancer. PMID:26273626

  13. SAM, the Starfire Optical Range Atmospheric Monitor

    NASA Astrophysics Data System (ADS)

    Spillar, Earl J.; Shoemake, Marjorie A.; Slavin, Ann C.

    2011-10-01

    We describe the Starfire Optical Range (SOR) Atmospheric Monitor (SAM). SAM is a 40 cm telescope feeding a Shack-Hartmann wave-front sensor with 20 subapertures across the telescope aperture, which in turn feeds a 1 kHz CCD camera. The unique features of SAM include the ability to work through both day and night and the ability to estimate r0 values down to 1.5 cm at 750 nm. Because SAM can measure 200 tilts simultaneously in 1 ms, it is able to detect rapid changes in turbulence parameters. It will be able to estimate the Fried parameter r0, the Greenwood parameter fg, scintillation, and a rough profile simultaneously. After describing the basic design and construction of SAM and our algorithm for estimating r0, we describe the initial capabilities of the system. We show some initial data regarding the diurnal variation of r0 at the SOR, simulations of SAM’s performance, and a validation against another system. We conclude with future plans for the system.

  14. Preparation of low-crystalline apatite nanoparticles and their coating onto quartz substrates.

    PubMed

    Kawashita, Masakazu; Taninai, Koji; Li, Zhixia; Ishikawa, Kunio; Yoshida, Yasuhiro

    2012-06-01

    We prepared low-crystalline apatite nanoparticles and coated them onto a surface of a Au/Cr-plated quartz substrate by the electrophoretic deposition (EPD) method or by using a self-assembled monolayer of 11-mercaptoundecanoic acid (SAM method). Low-crystalline apatite nanoparticles around 10 nm in size with extremely low contents of undesirable residual products were obtained by adding (NH(4))(2)HPO(4) aqueous droplets into a modified synthetic body fluid solution that contained Ca(CH(3)COO)(2). The apatite nanoparticles were successfully coated by either the EPD method or the SAM method; the nanoparticle coating achieved by the SAM method was more uniform than that achieved by the EPD method. The present SAM method is expected to be a promising technique for obtaining a quartz substrate coated with apatite nanoparticles, which can be used as a quartz crystal microbalance device.

  15. Characterization of self-assembled monolayers (SAMs) on silicon substrate comparative with polymer substrate for Escherichia coli O157:H7 detection

    NASA Astrophysics Data System (ADS)

    Moldovan, Carmen; Mihailescu, Carmen; Stan, Dana; Ruta, Lavinia; Iosub, Rodica; Gavrila, Raluca; Purica, Munizer; Vasilica, Schiopu

    2009-08-01

    This article presents the characterization of two substrates, silicon and polymer coated with gold, that are functionalized by mixed self-assembled monolayers (SAMs) in order to efficiently immobilize the anti- Escherichia coli O157:H7 polyclonal purified antibody. A biosurface functionalized by SAMs (self-assembled monolayers) technique has been developed. Immobilization of goat anti- E. coli O157:H7 antibody was performed by covalently bonding of thiolate mixed self-assembled monolayers (SAMs) realized on two substrates: polymer coated with gold and silicon coated with gold. The F(ab') 2 fragments of the antibodies have been used for eliminating nonspecific bindings between the Fc portions of antibodies and the Fc receptor on cells. The properties of the monolayers and the biofilm formatted with attached antibody molecules were analyzed at each step using infrared spectroscopy (FTIR-ATR), atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry (CV). In our study the gold-coated silicon substrates approach yielded the best results. These experimental results revealed the necessity to investigate each stage of the immobilization process taking into account in the same time the factors that influence the chemistry of the surface and the further interactions as well and also provide a solid basis for further studies aiming at elaborating sensitive and specific immunosensor or a microarray for the detection of E. coli O157:H7.

  16. Description of ferrocenylalkylthiol SAMs on gold by molecular dynamics simulations.

    PubMed

    Goujon, F; Bonal, C; Limoges, B; Malfreyt, P

    2009-08-18

    Molecular dynamics simulations of mixed monolayers consisting of Fc(CH2)12S-/C10S-Au SAMs are carried out to calculate structural (density profiles, angular distributions, positions of atoms) and energetic properties. The purpose of this paper is to explore the possible inhomogeneity of the neutral ferrocene moieties within the monolayer. Five systems have been studied using different grafting densities for the ferrocenylalkylthiolates. The angular distributions are described in terms of the relative contributions from isolated and clustered ferrocene moieties in the binary SAMs. It is shown that the energetic contributions strongly depend on the state of the ferrocene. The ability of molecular dynamics simulations to enable better understanding the SAM structure is illustrated in this work.

  17. Imaging and clinical findings in segmental arterial mediolysis (SAM).

    PubMed

    Alhalabi, Kinan; Menias, Christine; Hines, Robert; Mamoun, Ihsan; Naidu, Sailendra

    2017-02-01

    Segmental arterial mediolysis (SAM) is an uncommon, non-atherosclerotic, non-inflammatory arteriopathy that tends to affect the medium-sized splanchnic branches of the aorta along with renal, carotid, cerebral, and coronary arteries. The clinical presentation ranges from asymptomatic to severe, life-threatening intra-abdominal hemorrhage and shock. SAM overlaps clinically and radiologically with other inflammatory vasculitides. This article describes the pathologic-radiologic correlation, imaging findings, and the management of the disease. Radiologists should be familiar with this disease entity as imaging plays a crucial role in the diagnosis.

  18. Technoeconomic Modeling of Battery Energy Storage in SAM

    SciTech Connect

    DiOrio, Nicholas; Dobos, Aron; Janzou, Steven; Nelson, Austin; Lundstrom, Blake

    2015-09-01

    Detailed comprehensive lead-acid and lithium-ion battery models have been integrated with photovoltaic models in an effort to allow System Advisor Model (SAM) to offer the ability to predict the performance and economic benefit of behind the meter storage. In a system with storage, excess PV energy can be saved until later in the day when PV production has fallen, or until times of peak demand when it is more valuable. Complex dispatch strategies can be developed to leverage storage to reduce energy consumption or power demand based on the utility rate structure. This document describes the details of the battery performance and economic models in SAM.

  19. Obituary: Sam Roweis (1972-2010)

    NASA Astrophysics Data System (ADS)

    Hogg, David

    2011-12-01

    Computer scientist and statistical astronomer Sam Roweis took his own life in New York City on 2010 January 12. He was a brilliant and accomplished researcher in the field of machine learning, and a strong advocate for the use of computational statistics for automating discovery and scientific data analysis. He made several important contributions to astronomy and was working on adaptive astronomical data analysis at the time of his death. Roweis obtained his PhD in 1999 from the California Institute of Technology, where he worked on a remarkable range of subjects, including DNA computing, modeling of dynamical systems, signal processing, and speech recognition. During this time he unified and clarified some of the most important data analysis techniques, including Principal Component Analysis, Hidden Markov Models, and Expectation Maximization. His work was aimed at making data analysis and modeling faster, but also better justified scientifically. The last years of his PhD were spent in Princeton NJ, where he came in contact with a young generation of cosmologists thinking about microwave background and large-scale structure data. In a postdoc at University College London, Roweis co-created the Locally Linear Embedding (LLE) algorithm; a simple but flexible technique for mapping a large data set onto a low-dimensional manifold. The LLE paper obtained more than 2700 citations in 9 years, launched a new sub-field of machine learning known as "manifold learning," and inspired work in data visualization, search, and applied mathematics. In 2001, Roweis took a faculty job at the University of Toronto Computer Science Department. He continued working on data analysis methods that have probabilistic interpretation and therefore scientific applicability, but at the same time have good performance on large data sets. He was awarded a Sloan Fellowship, a Canada Research Chair, and a fellowship of the Canadian Institute for Advanced Research, among other honors and awards

  20. 77 FR 67813 - Sam Rayburn Dam Project Power Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-14

    ... Southwestern Power Administration Sam Rayburn Dam Project Power Rate AGENCY: Southwestern Power Administration, DOE. ACTION: Notice of Rate Order Approving an Extension of Power Rate on an Interim Basis. SUMMARY..., Assistant Administrator, Southwestern Power Administration, Department of Energy, Williams Center Tower...

  1. The fSAM Model of False Recall

    ERIC Educational Resources Information Center

    Kimball, Daniel R.; Smith, Troy A.; Kahana, Michael J.

    2007-01-01

    The authors report a new theory of false memory building upon existing associative memory models and implemented in fSAM, the first fully specified quantitative model of false recall. Participants frequently intrude unstudied critical words while recalling lists comprising their strongest semantic associates but infrequently produce other…

  2. SAMS Acceleration Measurement on Mir From March to September 1996

    NASA Technical Reports Server (NTRS)

    Moskowitz, Milton E.; Hrovat, Ken; Truong, Duc; Reckart, Timothy

    1997-01-01

    During NASA Increment 2 (March to September 1996), over 15 gigabytes of acceleration data were collected by the Space Acceleration Measurement System (SAMS) onboard the Russian Space Station, Mir. The data were recorded on 55 optical disks and were returned to Earth on STS-79. During this time, SAMS data were collected in the Kristall and Kvant modules, and in the Priroda module to support the following experiments: the Queen's University Experiments in Liquid Diffusion (QUELD), the Technological Evaluation of the MIM (TEM), the Forced Flow Flame Spreading Test (FFFT), and Candle Flames in Microgravity (CFM). This report points out some of the salient features of the microgravity environment to which these experiments were exposed. Also documented are mission events of interest such as the docked phase of STS-76 operations, an extravehicular activity (EVA) to install and deploy solar panels on the Kvant module, a Progress engine burn to raise Mir's altitude, and an on-orbit SAMS calibration procedure. Also included are a description of the Mir module orientations, and the panel notations within the modules. This report presents an overview of the SAMS acceleration measurements recorded by 10 Hz and 100 Hz sensor heads. Variations in the acceleration environment caused by unique activities such as crew exercise and life-support fans are presented. The analyses included herein complement those presented in previous mission summary reports published by the Principal Investigator Microgravity Services (PIMS) group.

  3. The Discovery of Polar Stratospheric Clouds by SAM II

    NASA Astrophysics Data System (ADS)

    Poole, L. R.; McCormick, M. P.

    2005-12-01

    Until the advent of spaceborne observations, clouds were thought to occur very rarely in the extremely dry stratosphere. This view changed dramatically following the launch of the Stratospheric Aerosol Measurement (SAM) II instrument on the Nimbus 7 spacecraft in October 1978. SAM II was a single channel solar photometer designed to measure stratospheric aerosol extinction profiles at a wavelength of 1.0 micron at latitudes from 64-80 degrees in both hemispheres. An analysis of SAM II data from the Arctic for January 1979 revealed a number of profiles in which the extinction was 1-2 orders of magnitude larger than expected. Careful study showed that these large extinction values were not artifacts, but were indeed due to dramatic reductions in the amount of solar radiance reaching the instrument. Further analyses showed that these so-called polar stratospheric clouds (PSCs) were observed only when the local stratospheric temperature was very low (185-200 K). The interest in PSCs was primarily academic until the discovery of the Antarctic ozone hole in 1985, which was quickly followed by studies associating this ozone depletion with the release of active chlorine through heterogeneous chemical reactions catalyzed by PSC particles. A large body of research over the ensuing two decades has firmly established this link. In this paper, we will recount the serendipitous discovery of PSCs in SAM II data more than 25 years ago and highlight other advances in our understanding of PSCs that have stemmed from spaceborne observations.

  4. Social Activity Method (SAM): A Fractal Language for Mathematics

    ERIC Educational Resources Information Center

    Dowling, Paul

    2013-01-01

    In this paper I shall present and develop my organisational language, "social activity method" (SAM), and illustrate some of its applications. I shall introduce a new scheme for "modes of recontextualisation" that enables the analysis of the ways in which one activity--which might be school mathematics or social research or any…

  5. Astronaut Curtis Brown works with SAMS on Shuttle Atlantis middeck

    NASA Technical Reports Server (NTRS)

    1994-01-01

    On the Space Shuttle Atlantis' mid-deck, astronaut Curtis L. Brown, pilot, works with the Space Acceleration Measurement System (SAMS), which is making its eleventh Shuttle flight. This system supports the Protein Crystal Growth (PCG) experiments onboard by collecting and recording data characterizing the microgravity environment in the Shuttle mid-deck.

  6. Information System through ANIS at CeSAM

    NASA Astrophysics Data System (ADS)

    Moreau, C.; Agneray, F.; Gimenez, S.

    2015-09-01

    ANIS (AstroNomical Information System) is a web generic tool developed at CeSAM to facilitate and standardize the implementation of astronomical data of various kinds through private and/or public dedicated Information Systems. The architecture of ANIS is composed of a database server which contains the project data, a web user interface template which provides high level services (search, extract and display imaging and spectroscopic data using a combination of criteria, an object list, a sql query module or a cone search interfaces), a framework composed of several packages, and a metadata database managed by a web administration entity. The process to implement a new ANIS instance at CeSAM is easy and fast : the scientific project has to submit data or a data secure access, the CeSAM team installs the new instance (web interface template and the metadata database), and the project administrator can configure the instance with the web ANIS-administration entity. Currently, the CeSAM offers through ANIS a web access to VO compliant Information Systems for different projects (HeDaM, HST-COSMOS, CFHTLS-ZPhots, ExoDAT,...).

  7. Wind Technology Modeling Within the System Advisor Model (SAM) (Poster)

    SciTech Connect

    Blair, N.; Dobos, A.; Ferguson, T.; Freeman, J.; Gilman, P.; Whitmore, J.

    2014-05-01

    This poster provides detail for implementation and the underlying methodology for modeling wind power generation performance in the National Renewable Energy Laboratory's (NREL's) System Advisor Model (SAM). SAM's wind power model allows users to assess projects involving one or more large or small wind turbines with any of the detailed options for residential, commercial, or utility financing. The model requires information about the wind resource, wind turbine specifications, wind farm layout (if applicable), and costs, and provides analysis to compare the absolute or relative impact of these inputs. SAM is a system performance and economic model designed to facilitate analysis and decision-making for project developers, financers, policymakers, and energy researchers. The user pairs a generation technology with a financing option (residential, commercial, or utility) to calculate the cost of energy over the multi-year project period. Specifically, SAM calculates the value of projects which buy and sell power at retail rates for residential and commercial systems, and also for larger-scale projects which operate through a power purchase agreement (PPA) with a utility. The financial model captures complex financing and rate structures, taxes, and incentives.

  8. MSL SAM-like Analyses of Hawaiian Altered Basaltic Materials: Implications for Analyses by the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    McAdam, A.; Eigenbrode, J. L.; Young, K. E.; Bleacher, J. E.; Knudson, C. A.; Rogers, D.; Glotch, T. D.; Sutter, B.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Downs, R. T.

    2015-12-01

    Samples of basaltic materials were collected during several traverses of the Kau Desert on the leeward side of the Kilauea Volcano, Hawaii, conducted by the Remote, In Situ, and Synchrotron Studies for Science and Exploration (RIS4E) team, a node of the Solar System Exploration and Research Virtual Institute (SSERVI) program. Some of these samples had been exposed to circumneutral to slightly acidic alteration conditions from exposure to fog/rain, and acidic fog/rain, while others had been exposed to more acidic conditions due to proximity to fumaroles. The samples consisted of basalts with coatings, sands and soils, and ash, and were collected using organically clean protocols to enable investigation of organic chemistry and organic-mineral associations, in addition to mineralogy. The Mars Science Laboratory (MSL) rover has analyzed basaltic materials inferred to have been altered under conditions ranging from circumneutral to acidic, but several aspects of the Sample Analysis at Mars (SAM) instrument suite results are still being investigated and analyses of relevant terrestrial analogs can play an important role in interpretation of the data. For example, all materials analyzed to date have a significant amorphous component. Comparisons of the mineralogy obtained with the MSL CheMin instrument and volatiles evolved during SAM analyses indicate that, by mass balance, some portion of the volatiles, such as SO2 and H2O, are likely associated with this component. Many of the RIS4E samples also have a significant amorphous component, and field x-ray diffraction (XRD) and x-ray fluorescence (XRF) data indicate differences in the chemistry of this material in samples exposed to different alteration conditions. Preliminary SAM-like analyses indicate that the amorphous materials in some of these samples evolve volatiles such as H2O and SO2 during heating. Here we will discuss these results, and others, obtained through SAM-like analyses of selected samples.

  9. DNA adenine methylation of sams1 gene in symbiont-bearing Amoeba proteus.

    PubMed

    Jeon, Taeck J

    2008-10-01

    The expression of amoeba sams genes is switched from sams1 to sams2 when amoebae are infected with Legionella jeonii. To elucidate the mechanism for the inactivation of host sams1 gene by endosymbiotic bacteria, methylation states of the sams1 gene of D and xD amoebae was compared in this study. The sams1 gene of amoebae was methylated at an internal adenine residue of GATC site in symbiont-bearing xD amoebae but not in symbiont-free D amoebae, suggesting that the modification might have caused the inactivation of sams1 in xD amoebae. The sams1 gene of xD amoebae was inactivated at the transcriptional level. Analysis of DNA showed that adenine residues in L. jeonii sams were also methylated, implying that L. jeonii bacteria belong to a Dam methylase-positive strain. In addition, both SAM and Met appeared to act as negative regulators for the expression of sams1 whereas the expression of sams2 was not affected in amoebae.

  10. An ADC for the SAM on the SOAR Telescope

    NASA Astrophysics Data System (ADS)

    Tighe, Roberto; Tokovinin, Andrei; Schurter, Patricio; Martínez, Manuel; Cantarutti, Rolando

    2016-08-01

    SAM (Soar Adaptive-optics Module), the SOAR (Southern Observatory for Astrophysical Research) GLAO facility is in service since 2011, with a UV, 355nm Laser Guide Star (LGS). The atmospheric wavefront error is therefore measured at 355nm and the star images are corrected in the visible range (BVRI bands). An ADC is required for High Resolution imaging at low telescope elevation, especially at shorter wavelengths of the visible spectrum. The ADC is based on 80mm diameter rotating prisms. This compact unit, fully automated, can be inserted or removed from the tightly constrained SAM collimated beam space-envelope, it adjusts to the parallactic angle and corrects the atmospheric dispersion. Here we present the optical and opto-mechanical design, the control design, the operational strategy and performance results obtained from extensive use in on-sky HR Speckle Imaging.

  11. Integration of sample analysis method (SAM) for polychlorinated biphenyls

    SciTech Connect

    Monagle, M.; Johnson, R.C.

    1996-05-01

    A completely integrated Sample Analysis Method (SAM) has been tested as part of the Contaminant Analysis Automation program. The SAM system was tested for polychlorinated biphenyl samples using five Standard Laboratory Modules{trademark}: two Soxtec{trademark} modules, a high volume concentrator module, a generic materials handling module, and the gas chromatographic module. With over 300 samples completed within the first phase of the validation, recovery and precision data were comparable to manual methods. Based on experience derived from the first evaluation of the automated system, efforts are underway to improve sample recoveries and integrate a sample cleanup procedure. In addition, initial work in automating the extraction of semivolatile samples using this system will also be discussed.

  12. First use of SAM onboard calibration gas cell

    NASA Astrophysics Data System (ADS)

    Malespin, C.; Trainer, M. G.; Manning, H. L.; Franz, H. B.; Conrad, P. G.; Raaen, E.; Webster, C. R.; Flesch, G.; Eigenbrode, J. L.; Wong, M. H.; Mahaffy, P. R.

    2015-12-01

    The Sample Analysis at Mars (SAM) instrument (Mahaffy et al 2012) suite on Curiosity completed its first measurement of the onboard calibration gas cell on MSL Mission Sol 1042. The cell consists of a gas mixture of four primary gases, along with trace fluorinated hydrocarbon high mass calibrants. The mix is comprised of approximately 25% CO2, N2, Xe and Ar, where the 129Xe has been given a three times enrichment relative to terrestrial xenon in order to distinguish it isotopically from Martian atmospheric Xe. Analysis of the calibration cell is intended to identify changes in instrument performance between pre-launch calibrations and operations on Mars, for any of the three main subsystems in SAM: the Quadrupole Mass Spectrometer (QMS), Tunable Laser Spectrometer (TLS), and Gas Chromatograph (GC). Here we present the experimental approach, results, and implications for instrument performance after almost three years of measurements on Mars.

  13. Spill Assessment Model (SAM) Procedure for Manual Field Calculations.

    DTIC Science & Technology

    1980-04-01

    SPECIFICALLY, THE PART OF SAM UTILIZED AS THE BASIS FOR THE FIELD CALCULATIONS ADDRESSES ONLY INSTANTANEOUS POINT SOURCE DISCHARGES INTO A FLOWING RIVER. FOR...instantaneous point source discharges into a flowing river. For field use, the primary requirement is to assess the maximum concentrations which may result...different classes of chemicals, reference sources such as the Chemical Hazard Response Information ,’stem (CHRIS) of the U.S. Coast Guard should be

  14. Technical Manual for the SAM Biomass Power Generation Model

    SciTech Connect

    Jorgenson, J.; Gilman, P.; Dobos, A.

    2011-09-01

    This technical manual provides context for the implementation of the biomass electric power generation performance model in the National Renewable Energy Laboratory's (NREL's) System Advisor Model (SAM). Additionally, the report details the engineering and scientific principles behind the underlying calculations in the model. The framework established in this manual is designed to give users a complete understanding of behind-the-scenes calculations and the results generated.

  15. The ALICE Glance Shift Accounting Management System (SAMS)

    NASA Astrophysics Data System (ADS)

    Martins Silva, H.; Abreu Da Silva, I.; Ronchetti, F.; Telesca, A.; Maidantchik, C.

    2015-12-01

    ALICE (A Large Ion Collider Experiment) is an experiment at the CERN LHC (Large Hadron Collider) studying the physics of strongly interacting matter and the quark-gluon plasma. The experiment operation requires a 24 hours a day and 7 days a week shift crew at the experimental site, composed by the ALICE collaboration members. Shift duties are calculated for each institute according to their correlated members. In order to ensure the full coverage of the experiment operation as well as its good quality, the ALICE Shift Accounting Management System (SAMS) is used to manage the shift bookings as well as the needed training. ALICE SAMS is the result of a joint effort between the Federal University of Rio de Janeiro (UFRJ) and the ALICE Collaboration. The Glance technology, developed by the UFRJ and the ATLAS experiment, sits at the basis of the system as an intermediate layer isolating the particularities of the databases. In this paper, we describe the ALICE SAMS development process and functionalities. The database has been modelled according to the collaboration needs and is fully integrated with the ALICE Collaboration repository to access members information and respectively roles and activities. Run, period and training coordinators can manage their subsystem operation and ensure an efficient personnel management. Members of the ALICE collaboration can book shifts and on-call according to pre-defined rights. ALICE SAMS features a user profile containing all the statistics and user contact information as well as the Institutes profile. Both the user and institute profiles are public (within the scope of the collaboration) and show the credit balance in real time. A shift calendar allows the Run Coordinator to plan data taking periods in terms of which subsystems shifts are enabled or disabled and on-call responsible people and slots. An overview display presents the shift crew present in the control room and allows the Run Coordination team to confirm the presence

  16. Mercury astronauts at the Sam Houston Colosseum, Houston, Texas

    NASA Technical Reports Server (NTRS)

    1962-01-01

    The original seven Mercury astronauts, each wearing new cowboy hats and a badge in the shape of a star, are pictured on stage at the Sam Houston Colosseum. A large crowd was on hand to welcome them to Houston, Texas. Left to right are astronauts M. Scott Carpenter, L. Gordon Cooper Jr., John H. Glenn Jr., Virgil I. Grissom, Walter M. Schirra Jr., Alan B. Shepard Jr., and Donald K. Slayton. Sen. John Tower (R.-Texas) is seen in far right background.

  17. Hydrophobic coatings for MEMS applications

    NASA Astrophysics Data System (ADS)

    Doms, M.; Feindt, H.; Kuipers, W. J.; Shewtanasoontorn, D.; Matar, A. S.; Brinkhues, S.; Welton, R. H.; Mueller, J.

    2008-05-01

    Different kinds of thin-film coatings were investigated with regard to their applicability as hydrophobic coatings for MEMS. The films were deposited onto silicon and borosilicate glass substrates by spincoating of Dyneon™ PTFE and PFA, plasmapolymerization of HMDS-N and C4F8 as well as liquid-phase and vapor-phase coating of SAMs from DDMS, FDTS, FOTS and Geleste Aquaphobe™ CM. The layer properties were analyzed using profilometry, FTIR, SEM and contact angle measurements. Furthermore, the adhesion of the layers to the substrates was determined in an acetone ultrasonic bath. The influence of various deposition process parameters on the properties of the films was investigated. As these layers can be used in microfluidic systems, as water-repellent layers and as anti-stiction coatings, they are suited for versatile fields of application.

  18. Summary Status of the Space Acceleration Measurement System (SAMS), September 1993

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard

    1994-01-01

    The Space Acceleration Measurement System (SAMS) was developed to measure the microgravity acceleration environment to which NASA science payloads are exposed during microgravity science missions on the shuttle. Six flight units have been fabricated to date. The inaugural flight of a SAMS unit was on STS-40 in June 1991 as part of the First Spacelab Life Sciences mission. Since that time, SAMS has flown on six additional missions and gathered eighteen gigabytes of data representing sixty-eight days of microgravity environment. The SAMS units have been flown in the shuttle middeck and cargo bay, in the Spacelab module, and in the Spacehab module. This paper summarizes the missions and experiments which SAMS has supported. The quantity of data and the utilization of the SAMS data is described. Future activities are briefly described for the SAMS project and the Microgravity Measurement and Analysis project (MMAP) to support science experiments and scientists with microgravity environment measurement and analysis.

  19. CE-SAM: a conversational interface for ISR mission support

    NASA Astrophysics Data System (ADS)

    Pizzocaro, Diego; Parizas, Christos; Preece, Alun; Braines, Dave; Mott, David; Bakdash, Jonathan Z.

    2013-05-01

    There is considerable interest in natural language conversational interfaces. These allow for complex user interactions with systems, such as fulfilling information requirements in dynamic environments, without requiring extensive training or a technical background (e.g. in formal query languages or schemas). To leverage the advantages of conversational interactions we propose CE-SAM (Controlled English Sensor Assignment to Missions), a system that guides users through refining and satisfying their information needs in the context of Intelligence, Surveillance, and Reconnaissance (ISR) operations. The rapidly-increasing availability of sensing assets and other information sources poses substantial challenges to effective ISR resource management. In a coalition context, the problem is even more complex, because assets may be "owned" by different partners. We show how CE-SAM allows a user to refine and relate their ISR information needs to pre-existing concepts in an ISR knowledge base, via conversational interaction implemented on a tablet device. The knowledge base is represented using Controlled English (CE) - a form of controlled natural language that is both human-readable and machine processable (i.e. can be used to implement automated reasoning). Users interact with the CE-SAM conversational interface using natural language, which the system converts to CE for feeding-back to the user for confirmation (e.g. to reduce misunderstanding). We show that this process not only allows users to access the assets that can support their mission needs, but also assists them in extending the CE knowledge base with new concepts.

  20. Sam68: a new STAR in the male fertility firmament.

    PubMed

    Sette, Claudio; Messina, Valeria; Paronetto, Maria Paola

    2010-01-01

    Male infertility accounts for approximately 50% of the cases of sterile human couples, and in many instances the genetic or molecular defects involved remain unknown. Studies conducted in animal models have elucidated the key role played by RNA-binding proteins and by the posttranscriptional regulation of gene expression during spermatogenesis. Ablation of proteins involved in each of the steps required for the processing and the utilization of messenger RNAs impairs the production of fertile spermatozoa. Recent evidence indicates that the RNA-binding protein Sam68 is absolutely required for the correct progression of spermatogenesis and for male fertility in the mouse. Sam68 belongs to the evolutionary conserved signal transduction and activation of RNA (STAR) family of RNA-binding proteins. The members of this family have been demonstrated to play crucial roles in cell differentiation and development, including male and female gametogenesis. In this review we will summarize the observations gathered on the functions of STAR proteins in different organisms, with particular emphasis on the role of Sam68 in male fertility.

  1. Mechanistic Enzymology of the Radical SAM Enzyme DesII.

    PubMed

    Ruszczycky, Mark W; Liu, Hung-Wen

    2015-04-01

    DesII is a member of the radical SAM family of enzymes that catalyzes radical-mediated transformations of TDP-4-amino-4,6-didexoy-D-glucose as well as other sugar nucleotide diphosphates. Like nearly all radical SAM enzymes, the reactions begin with the reductive homolysis of SAM to produce a 5'-deoxyadenosyl radical which is followed by regiospecific hydrogen atom abstraction from the substrate. What happens next, however, depends on the nature of the substrate radical so produced. In the case of the biosynthetically relevant substrate, a radical-mediated deamination ensues; however, when this amino group is replaced with a hydroxyl, one instead observes dehydrogenation. The factors that govern the fate of the initially generated substrate radical as well as the mechanistic details underlying these transformations have been a key focus of research into the chemistry of DesII. This review will discuss recent discoveries pertaining to the enzymology of DesII, how it may relate to understanding other radical-mediated lyases and dehydrogenases and the working hypotheses currently being investigated regarding the mechanism of DesII catalysis.

  2. SAMS Acceleration Measurements on Mir (NASA Increment 4)

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard

    1998-01-01

    During NASA Increment 4 (January to May 1997), about 5 gigabytes of acceleration data were collected by the Space Acceleration Measurements System (SAMS) onboard the Russian Space Station, Mir. The data were recorded on 28 optical disks which were returned to Earth on STS-84. During this increment, SAMS data were collected in the Priroda module to support the Mir Structural Dynamics Experiment (MiSDE), the Binary Colloidal Alloy Tests (BCAT), Angular Liquid Bridge (ALB), Candle Flames in Microgravity (CFM), Diffusion Controlled Apparatus Module (DCAM), Enhanced Dynamic Load Sensors (EDLS), Forced Flow Flame Spreading Test (FFFr), Liquid Metal Diffusion (LMD), Protein Crystal Growth in Dewar (PCG/Dewar), Queen's University Experiments in Liquid Diffusion (QUELD), and Technical Evaluation of MIM (TEM). This report points out some of the salient features of the microgravity environment to which these experiments were exposed. Also documented are mission events of interest such as the docked phase of STS-84 operations, a Progress engine bum, Soyuz vehicle docking and undocking, and Progress vehicle docking. This report presents an overview of the SAMS acceleration measurements recorded by 10 Hz and 100 Hz sensor heads. The analyses included herein complement those presented in previous summary reports prepared by the Principal Investigator Microgravity Services (PIMS) group.

  3. The SAMS: Smartphone Addiction Management System and verification.

    PubMed

    Lee, Heyoung; Ahn, Heejune; Choi, Samwook; Choi, Wanbok

    2014-01-01

    While the popularity of smartphones has given enormous convenience to our lives, their pathological use has created a new mental health concern among the community. Hence, intensive research is being conducted on the etiology and treatment of the condition. However, the traditional clinical approach based surveys and interviews has serious limitations: health professionals cannot perform continual assessment and intervention for the affected group and the subjectivity of assessment is questionable. To cope with these limitations, a comprehensive ICT (Information and Communications Technology) system called SAMS (Smartphone Addiction Management System) is developed for objective assessment and intervention. The SAMS system consists of an Android smartphone application and a web application server. The SAMS client monitors the user's application usage together with GPS location and Internet access location, and transmits the data to the SAMS server. The SAMS server stores the usage data and performs key statistical data analysis and usage intervention according to the clinicians' decision. To verify the reliability and efficacy of the developed system, a comparison study with survey-based screening with the K-SAS (Korean Smartphone Addiction Scale) as well as self-field trials is performed. The comparison study is done using usage data from 14 users who are 19 to 50 year old adults that left at least 1 week usage logs and completed the survey questionnaires. The field trial fully verified the accuracy of the time, location, and Internet access information in the usage measurement and the reliability of the system operation over more than 2 weeks. The comparison study showed that daily use count has a strong correlation with K-SAS scores, whereas daily use times do not strongly correlate for potentially addicted users. The correlation coefficients of count and times with total K-SAS score are CC = 0.62 and CC =0.07, respectively, and the t-test analysis for the

  4. Systematic biochemical characterization of the SAM domains in Eph receptor family from Mus Musculus.

    PubMed

    Wang, Yue; Li, Qingxia; Zheng, Yunhua; Li, Gang; Liu, Wei

    2016-05-13

    The Eph receptor family is the largest subfamily of receptor tyrosine kinases and well-known for their pivotal roles in axon guidance, synaptogenesis, artery/venous differentiation and tumorigenesis, etc. Activation of the Eph receptor needs multimerization of the receptors. The intracellular C-terminal SAM domain of Eph receptor was reported to mediate self-association of Eph receptors via the homo SAM-SAM interaction. In this study, we systematically expressed and purified the SAM domain proteins of all fourteen Eph receptors of Mus musculus in Escherichia coli. The FPLC (fast protein liquid chromatography) results showed the recombinant SAM domains were highly homogeneous. Using CD (circular dichroism) spectrometry, we found that the secondary structure of all the SAM domains was typically alpha helical folded and remarkably similar. The thermo-stability tests showed that they were quite stable in solution. SEC-MALS (size exclusion chromatography coupled with multiple angle light scattering) results illustrated 200 μM Eph SAM domains behaved as good monomers in the size-exclusion chromatography. More importantly, DLS (dynamic light scattering) results revealed the overwhelming majority of SAM domains was not multimerized in solution either at 200 μM or 2000 μM protein concentration, which indicating the SAM domain alone was not sufficient to mediate the polymerization of Eph receptor. In summary, our studies provided the systematic biochemical characterizations of the Eph receptor SAM domains and implied their roles in Eph receptor mediated signaling pathways.

  5. GABAergic inhibition shapes SAM responses in rat auditory thalamus.

    PubMed

    Cai, R; Caspary, D M

    2015-07-23

    Auditory thalamus (medial geniculate body [MGB]) receives ascending inhibitory GABAergic inputs from inferior colliculus (IC) and descending GABAergic projections from the thalamic reticular nucleus (TRN) with both inputs postulated to play a role in shaping temporal responses. Previous studies suggested that enhanced processing of temporally rich stimuli occurs at the level of MGB, with our recent study demonstrating enhanced GABA sensitivity in MGB compared to IC. The present study used sinusoidal amplitude-modulated (SAM) stimuli to generate modulation transfer functions (MTFs), to examine the role of GABAergic inhibition in shaping the response properties of MGB single units in anesthetized rats. Rate MTFs (rMTFs) were parsed into "bandpass (BP)", "mixed (Mixed)", "highpass (HP)" or "atypical" response types, with most units showing the Mixed response type. GABAA receptor blockade with iontophoretic application of the GABAA receptor (GABAAR) antagonist gabazine (GBZ) selectively altered the response properties of most MGB neurons examined. Mixed and HP units showed significant GABAAR-mediated SAM-evoked rate response changes at higher modulation frequencies (fms), which were also altered by N-methyl-d-aspartic acid (NMDA) receptor blockade (2R)-amino-5-phosphonopentanoate (AP5). BP units, and the lower arm of Mixed units responded to GABAAR blockade with increased responses to SAM stimuli at or near the rate best modulation frequency (rBMF). The ability of GABA circuits to shape responses at higher modulation frequencies is an emergent property of MGB units, not observed at lower levels of the auditory pathway and may reflect activation of MGB NMDA receptors (Rabang and Bartlett, 2011; Rabang et al., 2012). Together, GABAARs exert selective rate control over selected fms, generally without changing the units' response type. These results showed that coding of modulated stimuli at the level of auditory thalamus is at least, in part, strongly controlled by GABA

  6. Introducing the aerosol-climate model MAECHAM5-SAM2

    NASA Astrophysics Data System (ADS)

    Hommel, R.; Timmreck, C.; Graf, H. F.

    2009-04-01

    We are presenting a new global aerosol model MAECHAM5-SAM2 to study the aerosol dynamics in the UTLS under background and volcanic conditions. The microphysical core modul SAM2 treats the formation, the evolution and the transport of stratospheric sulphuric acid aerosol. The aerosol size distribution and the weight percentage of the sulphuric acid solution is calculated dependent on the concentrations of H2SO4 and H2O, their vapor pressures, the atmospheric temperature and pressure. The fixed sectional method is used to resolve an aerosol distribution between 1 nm and 2.6 micron in particle radius. Homogeneous nucleation, condensation and evaporation, coagulation, water-vapor growth, sedimentation and sulphur chemistry are included. The module is applied in the middle-atmosphere MAECHAM5 model, resolving the atmosphere up to 0.01 hPa (~80 km) in 39 layers. It is shown here that MAECHAM5-SAM2 well represents in-situ measured size distributions of stratospheric background aerosol in the northern hemisphere mid-latitudes. Distinct differences can be seen when derived integrated aerosol parameters (surface area, effective radius) are compared with aerosol climatologies based on the SAGE II satellite instrument (derived by the University of Oxford and the NASA AMES laboratory). The bias between the model and the SAGE II data increases as the moment of the aerosol size distribution decreases. Thus the modeled effective radius show the strongest bias, followed by the aerosol surface area density. Correspondingly less biased are the higher moments volume area density and the mass density of the global stratospheric aerosol coverage. This finding supports the key finding No. 2 of the SPARC Assessment of Stratospheric Aerosol Properties (2006), where it was shown that during periods of very low aerosol load in the stratosphere, the consistency between in-situ and satellite measurements, which exist in a volcanically perturbed stratosphere, breaks down and significant

  7. Paramagnetic Intermediates Generated by Radical S-Adenosylmethionine (SAM) Enzymes

    PubMed Central

    2015-01-01

    Conspectus A [4Fe–4S]+ cluster reduces a bound S-adenosylmethionine (SAM) molecule, cleaving it into methionine and a 5′-deoxyadenosyl radical (5′-dA•). This step initiates the varied chemistry catalyzed by each of the so-called radical SAM enzymes. The strongly oxidizing 5′-dA• is quenched by abstracting a H-atom from a target species. In some cases, this species is an exogenous molecule of substrate, for example, l-tyrosine in the [FeFe] hydrogenase maturase, HydG. In other cases, the target is a proteinaceous residue as in all the glycyl radical forming enzymes. The generation of this initial radical species and the subsequent chemistry involving downstream radical intermediates is meticulously controlled by the enzyme so as to prevent unwanted reactions. But the manner in which this control is exerted is unknown. Electron paramagnetic resonance (EPR) spectroscopy has proven to be a valuable tool used to gain insight into these mechanisms. In this Account, we summarize efforts to trap such radical intermediates in radical SAM enzymes and highlight four examples in which EPR spectroscopic results have shed significant light on the corresponding mechanism. For lysine 2,3-aminomutase, nearly each possible intermediate, from an analogue of the initial 5′-dA• to the product radical l-β-lysine, has been explored. A paramagnetic intermediate observed in biotin synthase is shown to involve an auxiliary [FeS] cluster whose bridging sulfide is a co-substrate for the final step in the biosynthesis of vitamin B7. In HydG, the l-tyrosine substrate is converted in unprecedented fashion to a 4-oxidobenzyl radical on the way to generating CO and CN– ligands for the [FeFe] cluster of hydrogenase. And finally, EPR has confirmed a mechanistic proposal for the antibiotic resistance protein Cfr, which methylates the unactivated sp2-hybridized C8-carbon of an adenosine base of 23S ribosomal RNA. These four systems provide just a brief survey of the ever-growing set

  8. Carbon extension in peptidylnucleoside biosynthesis by radical-SAM enzymes

    PubMed Central

    Lilla, Edward A.; Yokoyama, Kenichi

    2016-01-01

    Nikkomycins and polyoxins are antifungal peptidylnucleoside (PN) antibiotics active against human and plant pathogens. Here, we report that during PN biosynthesis in Streptomyces cacaoi and Streptomyces tendae, the C5′-extension of the nucleoside essential for downstream structural diversification is catalyzed by a conserved radical S-adenosyl-L-methionine (SAM) enzyme, PolH or NikJ. This is distinct from the nucleophilic mechanism reported for antibacterial nucleosides and represents a novel mechanism of nucleoside natural product biosynthesis. PMID:27642865

  9. The p53 status can influence the role of Sam68 in tumorigenesis

    PubMed Central

    Li, Naomi; Ngo, Chau Tuan-Anh; Aleynikova, Olga; Beauchemin, Nicole; Richard, Stéphane

    2016-01-01

    The expression and activities of RNA binding proteins are frequently dysregulated in human cancer. Their roles, however, appears to be complex, with reports indicating both pro-tumorigenic and tumor suppressive functions. Here we show, using two classical mouse cancer models, that the role of KH-type RNA binding protein, Sam68, in tumor development can be influenced by the status of the p53 tumor suppressor. We demonstrate that in mice expressing wild type p53, Sam68-deficiency resulted in a higher incidence and malignancy of carcinogen-induced tumors, suggesting a tumor suppressive role for Sam68. In marked contrast, Sam68-haploinsufficiency significantly delayed the onset of tumors in mice lacking p53 and prolonged their survival, indicating that Sam68 accelerates the development of p53-deficient tumors. These findings provide considerable insight into a previously unknown relationship between Sam68 and the p53 tumor suppressor in tumorigenesis. PMID:27690217

  10. Non-canonical active site architecture of the radical SAM thiamin pyrimidine synthase

    SciTech Connect

    Fenwick, Michael K.; Mehta, Angad P.; Zhang, Yang; Abdelwahed, Sameh H.; Begley, Tadhg P.; Ealick, Steven E.

    2015-03-27

    Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to generate a 5'-deoxyadenosyl radical. Canonical radical SAM enzymes are characterized by a β-barrel-like fold and SAM anchors to the differentiated iron of the cluster, which is located near the amino terminus and within the β-barrel, through its amino and carboxylate groups. Here we show that ThiC, the thiamin pyrimidine synthase in plants and bacteria, contains a tethered cluster-binding domain at its carboxy terminus that moves in and out of the active site during catalysis. In contrast to canonical radical SAM enzymes, we predict that SAM anchors to an additional active site metal through its amino and carboxylate groups. Superimposition of the catalytic domains of ThiC and glutamate mutase shows that these two enzymes share similar active site architectures, thus providing strong evidence for an evolutionary link between the radical SAM and adenosylcobalamin-dependent enzyme superfamilies.

  11. Cardiological aging in SAM model: effect of chronic treatment with growth hormone.

    PubMed

    Forman, K; Vara, E; García, C; Ariznavarreta, C; Escames, G; Tresguerres, J A F

    2010-06-01

    The purpose of this study was to investigate the effect of aging on different parameters related to inflammation, oxidative stress and apoptosis in hearts from two types of male mice models: senescence-accelerated mice (SAM-P8) and senescence-accelerated-resistant (SAM-R1), and the influence of chronic administration of Growth Hormone (GH) on old SAM-P8 mice. Forty male mice were used. Animals were divided into five experimental groups: two 10 month old untreated groups (SAM-P8/SAM-R1), two 2 month old young groups (SAM-P8/SAM-R1) and one 10 month old group (SAM-P8) treated with GH for 30 days. The expression of tumor necrosis factor-alpha, interleukin 1, interleukin 10, heme oxygenases 1 and 2, endothelial and inducible nitric oxide synthases, NFkB, Bad, Bax and Bcl-2 were determined by real-time reverse transcription polymerase chain reaction (RT-PCR). Results were submitted to a two way ANOVA statistical evaluation using the Statgraphics program. Inflammation, as well as, oxidative stress and apoptosis markers were increased in the heart of old SAM-P8 males, as compared to young controls and this situation was not observed in the old SAM-R1 mice. Exogenous GH administration reverted the effect of aging in the described parameters of old SAM-P8 mice. Our results suggest that inflammation, apoptosis and oxidative stress could play an important role in the observed cardiovascular alterations related to aging of SAM-P8 mice and that GH may play a potential protective effect on the cardiovascular system of these animals.

  12. Comparative studies of aerosol extinction measurements made by the SAM II and SAGE II satellite experiments

    NASA Technical Reports Server (NTRS)

    Yue, Glenn K.; Mccormick, M. P.; Chu, W. P.; Wang, P.; Osborn, M. T.

    1989-01-01

    Results from the Stratospheric Aerosol Measurement (SAM) II and Stratospheric Aerosol and Gas Experiment (SAGE) II are compared for measurement locations which are coincident in time and space. At 1.0 micron, the SAM II and SAGE II aerosol extinction profiles are similar within their measurement errors. In addition, sunrise and sunset aerosol extinction data at four different wavelengths are compared for occasions when the SAGE II and SAM II measurements are nearly coincident in space and about 12 hours apart.

  13. The nuclear protein Sam68 is cleaved by the FMDV 3C protease redistributing Sam68 to the cytoplasm during FMDV infection of host cells

    SciTech Connect

    Lawrence, Paul; Schafer, Elizabeth A.; Rieder, Elizabeth

    2012-03-30

    Picornavirus infection can lead to disruption of nuclear pore traffic, shut-off of cell translation machinery, and cleavage of proteins involved in cellular signal transduction and the innate response to infection. Here, we demonstrated that the FMDV 3C{sup pro} induced the cleavage of nuclear RNA-binding protein Sam68 C-terminus containing the nuclear localization sequence (NLS). Consequently, it stimulated the redistribution of Sam68 to the cytoplasm. The siRNA knockdown of Sam68 resulted in a 1000-fold reduction in viral titers, which prompted us to study the effect of Sam68 on FMDV post-entry events. Interestingly, Sam68 interacts with the internal ribosomal entry site within the 5 Prime non-translated region of the FMDV genome, and Sam68 knockdown decreased FMDV IRES-driven activity in vitro suggesting that it could modulate translation of the viral genome. The results uncover a novel role for Sam68 in the context of picornaviruses and the proteolysis of a new cellular target of the FMDV 3C{sup pro}.

  14. Conjugal immunity of Streptomyces strains carrying the integrative element pSAM2 is due to the pif gene (pSAM2 immunity factor).

    PubMed

    Possoz, Christophe; Gagnat, Josette; Sezonov, Guennadi; Guérineau, Michel; Pernodet, Jean-Luc

    2003-03-01

    Mechanisms of conjugal immunity preventing redundant exchange between two cells harbouring the same conjugative element have been reported in diverse bacteria. Such a system does exist for pSAM2, a conjugative and integrative element of Streptomyces. The apparition of the conjugative free form of pSAM2 in the donor strain during mating can be considered as the initial step of transfer. We analysed the genes involved in transfer inhibition by mating donors harbouring pSAM2 with recipient strains containing different regions of pSAM2. The conjugal immunity was previously thought to be mediated by the transcriptional repressor KorSA. Although the transfer efficiency is reduced by its presence in the recipient, the initiation of the transfer process is not affected. In contrast, the presence in the recipient strain of a single pSAM2 gene, pif (pSAM2 immunity factor), was sufficient to abolish both transfer and initiation of transfer. Thus, the clustered genes korSA and pif act complementarily to maintain pSAM2 in a 'prophage' state under non-conjugal conditions. KorSA is involved in intracellular signalling, whereas Pif participates in intercellular signalling. The Pif nudix motif is essential for its activity. This is the first protein of the nudix family shown to be involved in bacterial conjugation.

  15. Updates to Selected Analytical Methods for Environmental Remediation and Recovery (SAM)

    EPA Pesticide Factsheets

    View information on the latest updates to methods included in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM), including the newest recommended methods and publications.

  16. The first year: Development of a LANDSAT capability at Sam Houston State University

    NASA Technical Reports Server (NTRS)

    Bounds, J. H.

    1981-01-01

    Problems encountered in initiating a LANDSAT data processing capability at Sam Houston State University are discussed. Computer requirements, financing, and academic and administrative support are addressed.

  17. SAM-2 ground-truth plan: Correlative measurements for the Stratospheric Aerosol Measurement-2 (SAM 2) sensor on the Nimbus G satellite

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Mccormick, M. P.; Mcmaster, L. R.; Pepin, T. J.; Chu, W. P.; Swissler, T. J.

    1978-01-01

    The SAM-2 will fly aboard the Nimbus-G satellite for launch in the fall of 1978 and measure stratospheric vertical profiles of aerosol extinction in high latitude bands. The plan gives details of the location and times for the simultaneous satellite/correlative measurements for the nominal launch time, the rationale and choice of the correlative sensors, their characteristics and expected accuracies, and the conversion of their data to extinction profiles. The SAM-2 expected instrument performance and data inversion results are presented. Various atmospheric models representative of polar stratospheric aerosols are used in the SAM-2 and correlative sensor analyses.

  18. Regioselective patterning of multiple SAMs and applications in surface-guided smart microfluidics.

    PubMed

    Chen, Chuanzhao; Xu, Pengcheng; Li, Xinxin

    2014-12-24

    A top-down nanofabrication technology is developed to integrate multiple SAMs (self-assembled monolayers) into regioselective patterns. With ultraviolet light exposure through regioselectively hollowed hard mask, an existing SAM at designated microregions can be removed and a dissimilar kind of SAM can be regrown there. By repeating the photolithography-like process cycle, diverse kinds of SAM building blocks can be laid out as a desired pattern in one microfluidic channel. In order to ensure high quality of the surface modifications, the SAMs are vapor-phase deposited before the channel is closed by a bonding process. For the first time the technique makes it possible to integrate three or more kinds of SAMs in one microchannel. The technique is very useful for multiplex surface functionalization of microfluidic chips where different segments of a microfluidic channel need to be individually modified with different SAMs or into arrayed pattern for surface-guided fluidic properties like hydrophobicity/philicity and/or oleophobicity/philicity, etc. The technique has been well validated by experimental demonstration of various surface-directed flow-guiding functions. By modifying a microchannel surface into an arrayed pattern of multi-SAM "two-tone" stripe array, surface-guiding-induced 3D swirling flow is generated in a microfluidic channel that experimentally exhibits quick oil/water mixing and high-efficiency oil-to-water chemical extraction.

  19. Sam2bam: High-Performance Framework for NGS Data Preprocessing Tools

    PubMed Central

    Cheng, Yinhe; Tzeng, Tzy-Hwa Kathy

    2016-01-01

    This paper introduces a high-throughput software tool framework called sam2bam that enables users to significantly speed up pre-processing for next-generation sequencing data. The sam2bam is especially efficient on single-node multi-core large-memory systems. It can reduce the runtime of data pre-processing in marking duplicate reads on a single node system by 156–186x compared with de facto standard tools. The sam2bam consists of parallel software components that can fully utilize multiple processors, available memory, high-bandwidth storage, and hardware compression accelerators, if available. The sam2bam provides file format conversion between well-known genome file formats, from SAM to BAM, as a basic feature. Additional features such as analyzing, filtering, and converting input data are provided by using plug-in tools, e.g., duplicate marking, which can be attached to sam2bam at runtime. We demonstrated that sam2bam could significantly reduce the runtime of next generation sequencing (NGS) data pre-processing from about two hours to about one minute for a whole-exome data set on a 16-core single-node system using up to 130 GB of memory. The sam2bam could reduce the runtime of NGS data pre-processing from about 20 hours to about nine minutes for a whole-genome sequencing data set on the same system using up to 711 GB of memory. PMID:27861637

  20. Overview of SAM results obtained at Gale Crater during the 180 first sols

    NASA Astrophysics Data System (ADS)

    Coll, P.; Mahaffy, P. R.; Cabane, M.; Webster, C. R.; Archer, D.; Atreya, S. K.; Benna, M.; Brinckerhoff, W. B.; Brunner, A.; Buch, A.; Conrad, P.; Coscia, D.; Dobson, N.; Dworkin, J.; Eigenbrode, J.; Farley, K.; Flesch, G.; Franz, H.; Freissinet, C.; Galvin, D.; Gorevan, S.; Harpold, D.; Hengemihle, J.; Jaeger, F.; Johnson, C.; Johnson, M.; Jones, J.; Lefavor, M.; Leshin, L.; Lyness, E.; Malespin, C.; Manning, H.; Martin, D.; McAdam, A.; McKay, C.; Miller, K.; Ming, D. W.; Morris, R. V.; Navarro-González, R.; Niles, P.; Nolan, T.; Owen, T.; Pavolv, A.; Prats, B.; Pepin, R.; Raaen, E.; Raulin, F.; Steele, A.; Stern, J.; Squyres, S.; Sutter, B.; Summons, R. E.; Szopa, C.; Tan, F.; Teinturier, S.; Trainer, M.; Wong, M.; Wray, J.

    2013-09-01

    During the first 180 sols of Curiosity's landed mission on Mars (8/6/2012 to 2/7/2013) SAM sampled the atmosphere more than a dozen times, the dusty sandpile named Rocknest and a basin site named John Klein on the floor of Gale crater. The atmospheric experiments utilized SAM's quadrupole mass spectrometer (QMS) and its tunable laser spectrometer (TLS) while the solid sample experiments also utilized the gas chromatograph (GC). Although a number of core experiments were pre-programmed and stored in SAM EEProm, the high level SAM scripting language enabled the team to often optimize experiments based on prior runs. SAM and its Experiment Sequences exercised during the First 120 Sols: The SAM instruments, its gas processing system (GPS) and its sample manipulation system (SMS) have been already described [1]. During the first few weeks of the landed mission SAM carried out a variety of instrument health checks and then began a series of atmospheric experiments to measure atmospheric composition and isotope ratios. From sol 56 to 102 Curiosity lingered at Rocknest to clean out the surfaces of the sample processing system by scooping several times into this fine grained material, vibrating to abrade possible contamination from surfaces, and then discarding before delivery of sample to SAM from the 5th scoop.

  1. Winning Attitude & Dedication to Physical Therapy Keep Sam Schmidt on Track

    ERIC Educational Resources Information Center

    Bosley, Nikki Prevenslik

    2006-01-01

    This article relates how Sam Schmidt returned to living a productive life after an accident left him with spinal cord injury. Schmidt was a former Indy Racing League driver who founded Sam Schmidt Motorsports after his accident in 2000. Schmidt's car hit the wall as he exited turn two during a practice session at Walt Disney World Speedway in…

  2. High expression level and nuclear localization of Sam68 are associated with progression and poor prognosis in colorectal cancer

    PubMed Central

    2013-01-01

    Background Src-associated in mitosis (Sam68; 68 kDa) has been implicated in the oncogenesis and progression of several human cancers. The aim of this study was to investigate the clinicopathologic significance of Sam68 expression and its subcellular localization in colorectal cancer (CRC). Methods Sam68 expression was examined in CRC cell lines, nine matched CRC tissues and adjacent noncancerous tissues using reverse transcription (RT)-PCR, quantitative RT-PCR and Western blotting. Sam68 protein expression and localization were determined in 224 paraffin-embedded archived CRC samples using immunohistochemistry. Statistical analyses were applied to evaluate the clinicopathologic significance. Results Sam68 was upregulated in CRC cell lines and CRC, as compared with normal tissues; high Sam68 expression was detected in 120/224 (53.6%) of the CRC tissues. High Sam68 expression correlated significantly with poor differentiation (P = 0.033), advanced T stage (P < 0.001), N stage (P = 0.023) and distant metastasis (P = 0.033). Sam68 nuclear localization correlated significantly with poor differentiation (P = 0.002) and T stage (P =0.021). Patients with high Sam68 expression or Sam68 nuclear localization had poorer overall survival than patients with low Sam68 expression or Sam68 cytoplasmic localization. Patients with high Sam68 expression had a higher risk of recurrence than those with low Sam68 expression. Conclusions Overexpression of Sam68 correlated highly with cancer progression and poor differentiation in CRC. High Sam68 expression and Sam68 nuclear localization were associated with poorer overall survival. PMID:23937454

  3. S.A.M., the Italian Martian simulation chamber.

    PubMed

    Galletta, G; Ferri, F; Fanti, G; D'Alessandro, M; Bertoloni, G; Pavarin, D; Bettanini, C; Cozza, P; Pretto, P; Bianchini, G; Debei, S

    2006-12-01

    The Martian Environment Simulator (SAM "Simulatore di Ambiente Marziano") is a interdisciplinary project of Astrobiology done at University of Padua. The research is aimed to the study of the survival of the microorganisms exposed to the "extreme" planetary environment. The facility has been designed in order to simulate Mars' environmental conditions in terms of atmospheric pressure, temperature cycles and UV radiation dose. The bacterial cells, contained into dedicated capsules, will be exposed to thermal cycles simulating diurnal and seasonal Martian cycles. The metabolism of the different biological samples will be analysed at different phases of the experiment, to study their survival and eventual activity of protein synthesis (mortality, mutations and capability of DNA repairing). We describe the experimental facility and provide the perspectives of the biological experiments we will perform in order to provide hints on the possibility of life on Mars either autochthonous or imported from Earth.

  4. Radical SAM-Mediated Methylation of Ribosomal RNA

    PubMed Central

    Stojkovic, Vanja; Fujimori, Danica Galonić

    2015-01-01

    Post-transcriptional modifications of RNA play an important role in a wide range of biological processes. In ribosomal RNA (rRNA), methylation of nucleotide bases is the predominant modification. In recent years, methylation of adenosine 2503 (A2503) in bacterial 23S rRNA has attracted significant attention due to both the unusual regioselectivity of the methyl group incorporation, as well as the pathophysiological roles of the resultant methylations. Specifically, A2503 is methylated at the C2 and C8 positions of the adenine ring, and the introduced modifications have a profound impact on translational fidelity and antibiotic resistance, respectively. These modifications are performed by RlmN and Cfr, two members, of the recently discovered class of radical S-adenosylmethionine (radical SAM) methylsynthases. Here, we present several methods that can be used to evaluate the activity of these enzymes, under both in vivo and in vitro conditions. PMID:26253978

  5. Solution structure of the first Sam domain of Odin and binding studies with the EphA2 receptor.

    PubMed

    Mercurio, Flavia Anna; Marasco, Daniela; Pirone, Luciano; Pedone, Emilia Maria; Pellecchia, Maurizio; Leone, Marilisa

    2012-03-13

    The EphA2 receptor plays key roles in many physiological and pathological events, including cancer. The process of receptor endocytosis and the consequent degradation have attracted attention as possible means of overcoming the negative outcomes of EphA2 in cancer cells and decreasing tumor malignancy. A recent study indicates that Sam (sterile alpha motif) domains of Odin, a member of the ANKS (ankyrin repeat and sterile alpha motif domain-containing) family of proteins, are important for the regulation of EphA2 endocytosis. Odin contains two tandem Sam domains (Odin-Sam1 and -Sam2). Herein, we report on the nuclear magnetic resonance (NMR) solution structure of Odin-Sam1; through a variety of assays (employing NMR, surface plasmon resonance, and isothermal titration calorimetry techniques), we clearly demonstrate that Odin-Sam1 binds to the Sam domain of EphA2 in the low micromolar range. NMR chemical shift perturbation experiments and molecular modeling studies point out that the two Sam domains interact with a head-to-tail topology characteristic of several Sam-Sam complexes. This binding mode is similar to that we have previously proposed for the association between the Sam domains of the lipid phosphatase Ship2 and EphA2. This work further validates structural elements relevant for the heterotypic Sam-Sam interactions of EphA2 and provides novel insights for the design of potential therapeutic compounds that can modulate receptor endocytosis.

  6. Social activity method (SAM): A fractal language for mathematics

    NASA Astrophysics Data System (ADS)

    Dowling, Paul

    2013-09-01

    In this paper I shall present and develop my organisational language, social activity method (SAM), and illustrate some of its applications. I shall introduce a new scheme for modes of recontextualisation that enables the analysis of the ways in which one activity - which might be school mathematics or social research or any empirically observed regularity of practice - recontextualises the practice of another and I shall also present, deploy, and develop an existing scheme - domains of action - in an analysis of school mathematics examination papers and in the structuring of what I refer to as the esoteric domain. This domain is here conceived as a hybrid domain of, first, linguistic and extralinguistic resources that are unambiguously mathematical in terms of both expression and content and, second, pedagogic theory - often tacit - that enables the mathematical gaze onto other practices and so recontextualises them. A second and more general theme that runs through the paper is the claim that there is nothing that is beyond semiosis, that there is nothing to which we have direct access, unmediated by interpretation. This state of affairs has implications for mathematics education. Specifically, insofar as an individual's mathematical semiotic system is under continuous development - the curriculum never being graspable all at once - understanding - as a stable semiotic moment - of any aspect or object of mathematics is always localised to the individual and is at best transient, and the sequencing of such moments may well also be more individualised than consistent in some correspondence with the sequencing of the curriculum. This being the case, a concentration on understanding as a goal may well serve to inhibit the pragmatic acquisition and deployment of mathematical technologies, which should be the principal aim of mathematics teaching and learning. The paper is primarily concerned with mathematics education. SAM, however, is a language that is available for

  7. Economic Analysis Case Studies of Battery Energy Storage with SAM

    SciTech Connect

    DiOrio, Nicholas; Dobos, Aron; Janzou, Steven

    2015-11-01

    Interest in energy storage has continued to increase as states like California have introduced mandates and subsidies to spur adoption. This energy storage includes customer sited behind-the-meter storage coupled with photovoltaics (PV). This paper presents case study results from California and Tennessee, which were performed to assess the economic benefit of customer-installed systems. Different dispatch strategies, including manual scheduling and automated peak-shaving were explored to determine ideal ways to use the storage system to increase the system value and mitigate demand charges. Incentives, complex electric tariffs, and site specific load and PV data were used to perform detailed analysis. The analysis was performed using the free, publically available System Advisor Model (SAM) tool. We find that installation of photovoltaics with a lithium-ion battery system priced at $300/kWh in Los Angeles under a high demand charge utility rate structure and dispatched using perfect day-ahead forecasting yields a positive net-present value, while all other scenarios cost the customer more than the savings accrued. Different dispatch strategies, including manual scheduling and automated peak-shaving were explored to determine ideal ways to use the storage system to increase the system value and mitigate demand charges. Incentives, complex electric tariffs, and site specific load and PV data were used to perform detailed analysis. The analysis was performed using the free, publically available System Advisor Model (SAM) tool. We find that installation of photovoltaics with a lithium-ion battery system priced at $300/kWh in Los Angeles under a high demand charge utility rate structure and dispatched using perfect day-ahead forecasting yields a positive net-present value, while all other scenarios cost the customer more than the savings accrued.

  8. Radical SAM catalysis via an organometallic intermediate with an Fe-[5'-C]-deoxyadenosyl bond.

    PubMed

    Horitani, Masaki; Shisler, Krista; Broderick, William E; Hutcheson, Rachel U; Duschene, Kaitlin S; Marts, Amy R; Hoffman, Brian M; Broderick, Joan B

    2016-05-13

    Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to cleave SAM to initiate diverse radical reactions. These reactions are thought to involve the 5'-deoxyadenosyl radical intermediate, which has not yet been detected. We used rapid freeze-quenching to trap a catalytically competent intermediate in the reaction catalyzed by the radical SAM enzyme pyruvate formate-lyase activating enzyme. Characterization of the intermediate by electron paramagnetic resonance and (13)C, (57)Fe electron nuclear double-resonance spectroscopies reveals that it contains an organometallic center in which the 5' carbon of a SAM-derived deoxyadenosyl moiety forms a bond with the unique iron site of the [4Fe-4S] cluster. Discovery of this intermediate extends the list of enzymatic bioorganometallic centers to the radical SAM enzymes, the largest enzyme superfamily known, and reveals intriguing parallels to B12 radical enzymes.

  9. Sam68 is Overexpressed in Epithelial Ovarian Cancer and Promotes Tumor Cell Proliferation

    PubMed Central

    Dong, Lijuan; Che, Hailuo; Li, Mingmei; Li, Xuepeng

    2016-01-01

    Background Epithelial ovarian cancer (EOC) is the deadliest gynecological malignancy, and evidence is accumulating on how molecular markers may be associated with the origin and process of EOC. Sam68 (Src-associated in mitosis, of 68 kD), is a K homology domain RNA-binding protein that has been investigated as a risk factor in multiple types of tumors. The aim of the present study was to investigate the contribution of the Sam68 gene in the pathogenesis of EOC. Material/Methods Western blot assay and real-time quantitative PCR methods were performed to examine Sam68 expression in EOC tissue specimens. The association of Sam68 expression with clinic-pathologic variables of EOC was evaluated. Then gain-of-function and loss-of-function strategies were adopted to examine the regulation of Sam68 on the proliferation of EOC OVCAR-3 cells using CCK-8 and colony forming assays. Results Sam68 was overexpressed in both mRNA and protein levels in EOC tumor tissue (n=152) in an association with malignant factors of EOC such as International Federation of Gynecology and Obstetrics (FIGO) stage, residual tumor size (cm), histological grade, and lymph node metastasis. In vitro results demonstrated that Sam68 overexpression was upregulated while Sam68 knockdown downregulated the proliferation of EOC OVCAR-3 cells via regulation of cell growth and colony formation. Conclusions Sam68 was overexpressed in EOC tissue in association with such cancer malignant factors of FIGO stage, histological grade, and lymph node metastasis, and also positively regulated the proliferation of EOC cells. Our research suggests that Sam68 might accelerate cell cycle progression, and present as a prognostic marker for EOC. PMID:27623016

  10. Analysis of trace degradation products (decarboxylated diastereoisomers) of S-adenosylmethionine by electrophoresis in capillaries with cationic coatings (N-methylpolyvinylpyridinium or divalent barium).

    PubMed

    Sebastiano, Roberto; Knob, Radim; Citterio, Attilio; Righetti, Pier Giorgio

    2010-10-01

    Commercial preparations of S-adenosylmethionine (SAM) when analyzed in uncoated capillaries show a minute impurity believed to be decarboxylated (dc) SAM. By using two types of cationic coatings, thus reducing the electro-endo-osmotic flow (EOF), it was possible to separate this impurity into two diastereoisomers of dcSAM. The coatings evaluated for this purpose were: (i) N-methylpolyvinylpyridinium, used under reversed EOF at acidic conditions (pH 4.0) and (ii) deposition of divalent barium at alkaline pH values (pH 9.4), providing reduced EOF. Under these conditions, it was possible to separate this impurity into two diastereoisomers, which by chemical synthesis were indeed proven to be dcSAM. It was further demonstrated that, in the alkylation of 5'-methylthioadenosine by 3-bromopropylamine in bromidric acid to dcSAM, another minute impurity was present, proven, via mass spectrometry, to consist of S-(5'-adenosyl)-3-thiopropylamine (decarboxylated and demethylated (dc-SAH)). The LOD for the two dcSAM diastereoisomers was assessed as 17.5 μg/mL and their LOQ as 25.5 μg/mL. By the barium-based protocol it was possible to quantify the dcSAM, present in a commercial sample of SAM, as a 0.1% impurity.

  11. Mechano-Chemical Stability of Gold Nanoparticles Coated With Alkanethiolate SAMs

    DTIC Science & Technology

    2009-12-01

    related to the passivation layer investigated computationally include changes in the internal pressure and surface tension (24). This report is...nanoparticle or droplet is typically positive, indicating a compressive surface tension . The radial pressure distribution for an uncoated 50-Å gold...increases, the surface pressure decreases. This decrease of pressure with increasing temperature is expected because the reported surface tension

  12. SAMS Acceleration Measurements on Mir from November 1995 to March 1996

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard

    1997-01-01

    The NASA Microgravity Science and Applications Division (MSAD) sponsors science experiments on a variety of microgravity carriers, including Orbiter missions and Russia's Mir space station. The MSAD sponsors the Space Acceleration Measurement System (SAMS) at the NASA Lewis Research Center (LERC) to support these science experiments by providing acceleration measurements to characterize the microgravity environment to which the experiments were exposed. The LeRC Principal Investigator Microgravity Services (PIMS) project supports principal investigations of microgravity science experiments as they evaluate the effects of varying acceleration levels on their experiments. In 1994, a SAMS unit was installed on the Mir space station. In a manner similar to Orbiter mission support, the SAMS unit supports science experiments from the U.S. and Russia by measuring the microgravity environment during experiment operations. Previous reports have summarized the SAMS data acquired during the period from September 1994 to November 1995. During the time period from November 1995 to March 1996, the primary SAMS-supported experiment was a Protein Crystal Growth (PCG) experiment. SAMS data were obtained during the PCG operations on Mir in accordance with the requirements specified by the PCG Principal Investigator. Also included in this data are mission events of interest, such as the undocking of STS-74 from Mir (November 1995) and the docking of Atlantis (STS-76) to Mir in March 1996. This report presents an overview of the SAMS data recorded in the interval from November 1995 to March 1996.

  13. The integrated conjugative plasmid pSAM2 of Streptomyces ambofaciens is related to temperate bacteriophages.

    PubMed

    Boccard, F; Smokvina, T; Pernodet, J L; Friedmann, A; Guérineau, M

    1989-03-01

    Streptomyces ambofaciens ATCC23877 and derivatives contain the 11-kb element pSAM2 present in an integrated state or as a free and integrated plasmid. This element, able to integrate site-specifically in the genome of different Streptomyces species, is conjugative and mobilizes chromosomal markers. Besides these plasmid functions, we have shown that the site-specific recombination system of pSAM2 presents strong similarities with that of several temperate phages. The integration event is promoted by a site-specific recombinase of the integrase family. The int gene encoding this integrase is closely linked to the plasmid attachment site (attP). A small open reading frame (ORF) overlaps the int gene and the predicted protein exhibits similarities with Xis proteins involved in phages excision. The integrated copy of pSAM2 in strain ATCC23877 is flanked by att sequences (attL and attR). Another att sequence (attX) is present in this strain and attX and attL are the boundaries of a 42-kb fragment (xSAM1) absent, as well as pSAM2, from S.ambofaciens DSM40697. Sequences partially similar to pSAM2 int gene are found near the chromosomal integration zone in both S.ambofaciens strains. The possible origin of pSAM2, an element carrying plasmid as well as phage features, is discussed.

  14. The integrative element pSAM2 from Streptomyces: kinetics and mode of conjugal transfer.

    PubMed

    Possoz, C; Ribard, C; Gagnat, J; Pernodet, J L; Guérineau, M

    2001-10-01

    pSAM2 is an 11 kb integrative element from Streptomyces ambofaciens that is capable of conjugal transfer. A system based on differential DNA modification by SalI methyltransferase was used to localize pSAM2 in the donor or recipient strain, and thus to determine the various steps associated with transfer. Initiation (i.e. excision and replication of pSAM2 in the donor) occurs a few hours after mating with a recipient strain. pSAM2 replicates in the recipient strain, spreads within the mycelium and then integrates into the chromosome. Transfer generally involves single-stranded DNA. In Streptomyces, only a few genes, such as traSA for pSAM2, are required for conjugal transfer. Using the differential sensitivity to the SalI restriction-modification system of transfers involving single- and double-stranded DNA, we found that pSAM2 was probably transferred to the recipient as double-stranded DNA. This provides the first experimental evidence for the transfer of double-stranded DNA during bacterial conjugation. Thus, TraSA, involved in pSAM2 transfer, and SpoIIIE, which is involved in chromosome partitioning in Bacillus subtilis, display similarities in both sequence and function: both seem to transport double-stranded DNA actively, either from donor to recipient or from mother cell to prespore.

  15. The association of Sam68 with Vav1 contributes to tumorigenesis.

    PubMed

    Lazer, Galit; Pe'er, Liron; Schapira, Vered; Richard, Stéphane; Katzav, Shulamit

    2007-12-01

    Vav1 functions in the hematopoietic system as a specific GDP/GTP nucleotide exchange factor regulated by tyrosine phosphorylation. An intact C-terminal SH3 domain of Vav1 (Vav1SH3C) was shown to be necessary for Vav1-induced transformation, yet the associating protein(s) necessary for this activity have not yet been identified. Using a proteomics approach, we identified Sam68 as a Vav1SH3C-associating protein. Sam68 (Src-associated in mitosis of 68 kD) belongs to the heteronuclear ribonucleoprotein particle K (hnRNP-K) homology (KH) domain family of RNA-binding proteins. The Vav1/Sam68 interaction was observed in vitro and in vivo. Mutants of Vav1SH3C previously shown to lose their transforming potential did not associate with Sam68. Co-expression of Vav1 and Sam68 in Jurkat T cells led to increased localization of Vav1 in the nucleus and changes in cell morphology. We then tested the contribution of Sam68 to known functions of Vav1, such as focus-forming in NIH3T3 fibroblasts and NFAT stimulation in T cells. Co-expression of oncogenic Vav1 with Sam68 in NIH3T3 fibroblasts resulted in a dose-dependent increase in foci, yet no further enhancement of NFAT activity was observed in Jurkat T cells, as compared to cells overexpressing only Vav1 or Sam68. Our results strongly suggest that Sam68 contributes to transformation by oncogenic Vav1.

  16. Sam68 Mediates the Activation of Insulin and Leptin Signalling in Breast Cancer Cells

    PubMed Central

    Pérez-Pérez, Antonio; Sánchez-Jiménez, Flora; Vilariño-García, Teresa; de la Cruz, Luis; Virizuela, Juan A.; Sánchez-Margalet, Víctor

    2016-01-01

    Obesity is a well-known risk factor for breast cancer development in postmenopausal women. High insulin and leptin levels seem to have a role modulating the growth of these tumours. Sam68 is an RNA-binding protein with signalling functions that has been found to be overexpressed in breast cancer. Moreover, Sam68 may be recruited to insulin and leptin signalling pathways, mediating its effects on survival, growth and proliferation in different cellular types. We aimed to study the expression of Sam68 and its phosphorylation level upon insulin and leptin stimulation, and the role of Sam68 in the proliferative effect and signalling pathways that are activated by insulin or leptin in human breast adenocarcinoma cells. In the human breast adenocarcinoma cell lines MCF7, MDA-MB-231 and BT-474, Sam68 protein quantity and gene expression were increased upon leptin or insulin stimulation, as it was checked by qPCR and immunoblot. Moreover, both insulin and leptin stimulation promoted an increase in Sam68 tyrosine phosphorylation and negatively regulated its RNA binding capacity. siRNA was used to downregulate Sam68 expression, which resulted in lower proliferative effects of both insulin and leptin, as well as a lower activation of MAPK and PI3K pathways promoted by both hormones. These effects may be partly explained by the decrease in IRS-1 expression by down-regulation of Sam68. These results suggest the participation of Sam68 in both leptin and insulin receptor signaling in human breast cancer cells, mediating the trophic effects of these hormones in proliferation and cellular growth. PMID:27415018

  17. A comparative study of aerosol extinction measurements made by the SAM II and SAGE satellite experiments

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Mccormick, M. P.; Chu, W. P.

    1984-01-01

    SAM II and SAGE are two satellite experiments designed to measure stratospheric aerosol extinction using the technique of solar occultation or limb extinction. Although each sensor is mounted aboard a different satellite, there are occasions when their measurement locations are nearly coincident, thereby providing opportunities for a measurement comparison. In this paper, the aerosol extinction profiles and daily contour plots for some of these events in 1979 are reported. The comparisons shown in this paper demonstrate that SAM II and SAGE are producing similar aerosol extinction profiles within their measurement errors and that since SAM II has been previously validated, these results show the validity of the SAGE aerosol measurements.

  18. The fSAM Model of False Recall

    PubMed Central

    Kimball, Daniel R.; Smith, Troy A.; Kahana, Michael J.

    2009-01-01

    The authors report a new theory of false memory building upon existing associative memory models and implemented in fSAM, the first fully specified quantitative model of false recall. Participants frequently intrude unstudied critical words while recalling lists comprising their strongest semantic associates but infrequently produce other extralist and prior-list intrusions. The authors developed the theory by simulating recall of such lists, using factorial combinations of semantic mechanisms operating at encoding, retrieval, or both stages. During encoding, unstudied words' associations to list context were strengthened in proportion to their strength of semantic association either to each studied word or to all co-rehearsed words. During retrieval, words received preference in proportion to their strength of semantic association to the most recently recalled single word or multiple words. The authors simulated all intrusion types and veridical recall for lists varying in semantic association strength among studied and critical words from the same and different lists. Multiplicative semantic encoding and retrieval mechanisms performed well in combination. Using such combined mechanisms, the authors also simulated several core findings from the Deese–Roediger–McDermott paradigm literature, including developmental patterns, specific list effects, association strength effects, and true–false correlations. These results challenge existing false-memory theories. PMID:17907869

  19. OARE and SAMS on STS-94/MSL-1

    NASA Technical Reports Server (NTRS)

    Moskowitz, Milton; Hrovat, Kenneth; McPherson, Kevin; Tschen, Peter; DeLombard, Richard; Nati, Maurizio

    1998-01-01

    Four microgravity acceleration measurement instruments were included on MSL-1 to measure the accelerations and vibrations to which science experiments were exposed during their operation on the mission. The data were processed and presented to the principal investigators in a variety of formats to aid their assessment of the microgravity environment during their experiment operations. Two accelerometer systems managed by the NASA Lewis Research Center (LeRC) supported the MSL-1 mission: the Orbital Acceleration Research Experiment (OARE), and the Space Acceleration Measurement System (SAMS). In addition, the Microgravity Measurement Assembly (MMA) and the Quasi- Steady Acceleration Measurement (QSAM) system, both sponsored by the Microgravity Research Division, collected acceleration data as a part of the MSL-1 mission. The NIMA was funded and designed by the European Space Agency in the Netherlands (ESA/ESTEC), and the QSAM system was funded and designed by the German Space Agency (DLR). The Principal Investigator Microgravity Services (PIMS) project at the NASA Lewis Research Center (LeRC) supports Principal Investigators (PIs) of the Microgravity science community as they evaluate the effects of acceleration on their experiments. PIMS primary responsibility is to support NASA-sponsored investigators in the area of acceleration data analysis and interpretation. A mission summary report was prepared and published by PIMS in order to furnish interested experiment investigators with a guide for evaluating the acceleration environment during the MSL-1 mission.

  20. Sam Goudsmit--His Physics and His Statesmanship

    NASA Astrophysics Data System (ADS)

    Bederson, Benjamin

    2010-03-01

    Sam Goudsmit was already a famous theoretical physicist in his thirties, mainly because of his co-discovery of electron spin with George Uhlenbeck while both were students of Paul Ehrenfest in Holland in 1925. He and Uhlenbeck continued their thriving careers at the University of Michigan. Goudsmit's style as a physicist was always to make as close a connection between theory and experiment as possible. Thus, for example, his development with his student Robert Bacher of the technique called ``fractional parentage'' used fruitfully in both atomic and nuclear physics to compute energy levels of unknown states in terms of know ones. He also delved deeply into problems related to determinations of nuclear spins and moments. Partly because of his service as scientific leader of the Alsos project at the end of WWII he became a leading statesman of science. I will describe some of his achievements both as a physicist and as a statesman, prior to his becoming Editor in Chief of the American Physical Society.

  1. Tandem SAM Domain Structure of Human Caskin1: A Presynaptic, Self-Assembling Scaffold for CASK

    SciTech Connect

    Stafford, Ryan L.; Hinde, Elizabeth; Knight, Mary Jane; Pennella, Mario A.; Ear, Jason; Digman, Michelle A.; Gratton, Enrico; Bowie, James U.

    2012-02-07

    The synaptic scaffolding proteins CASK and Caskin1 are part of the fibrous mesh of proteins that organize the active zones of neural synapses. CASK binds to a region of Caskin1 called the CASK interaction domain (CID). Adjacent to the CID, Caskin1 contains two tandem sterile a motif (SAM) domains. Many SAM domains form polymers so they are good candidates for forming the fibrous structures seen in the active zone. We show here that the SAM domains of Caskin1 form a new type of SAM helical polymer. The Caskin1 polymer interface exhibits a remarkable segregation of charged residues, resulting in a high sensitivity to ionic strength in vitro. The Caskin1 polymers can be decorated with CASK proteins, illustrating how these proteins may work together to organize the cytomatrix in active zones.

  2. Stability of binary SAMs formed by omega-acid and alcohol functionalized thiol mixtures.

    PubMed

    Tielens, Frederik; Humblot, Vincent; Pradier, Claire-Marie; Calatayud, Monica; Illas, Francesc

    2009-09-01

    A simple model is presented to describe the mixing process of acid- and alcohol-terminated thiol self-assembled monolayers (SAMs) on Au(111). It was found that the low-concentration acid-terminated SAMs are enriched in acid thiol compared with the original solution from which the SAM is made. Due to the relatively strong interaction between acid and alcohol head groups, homogeneously mixed SAMs showing alcohol/acid pairs are preferred when the acid-terminated thiol fraction in solution is below or equal to 50%. This particular behavior affecting the mixing process is explained using atomistic first-principle thermodynamics. The calculated phase diagram has been discussed and interpreted with the help of XPS.

  3. Surface adhesion and confinement variation of Bacillus subtilis on SAM surfaces

    NASA Astrophysics Data System (ADS)

    Swiger, Lauren; Pasquale, Rose; Calabrese, Joseph; Senevirathne, Indrajith

    2012-02-01

    Controlled surface adhesion of non - pathogenic gram positive strain, Bacillus subtilis is interesting as a model system due to possible development of respective biosensors for prevention and detection of the pathogenic variants B. anthracis and B. cereus. Further as a study for bio-machine interfacing systems. Self Assembled Monolayers (SAM) with engineered surfaces of linear thiols on Au(111) were used as the substrate. Sub cultured B. subtilis were used for the analysis. The SAM layered surfaces were dipped in 2 -- 5 Log/ml B. subtilis solution. Subsequent surface adhesion at different bacterial dilutions on surfaces will be discussed, and correlated with quantitative and qualitative adhesion properties of bacteria on the engineered SAM surfaces. The bacteria adhered SAM surfaces were investigated using intermittent contact, noncontact, lateral force and contact modes of Atomic Force Microscopy (AFM).

  4. Surface adhesion and confinement variation of Staphylococcus aurius on SAM surfaces

    NASA Astrophysics Data System (ADS)

    Amroski, Alicia; Olsen, Morgan; Calabrese, Joseph; Senevirathne, Reshani; Senevirathne, Indrajith

    2012-02-01

    Controlled surface adhesion of non - pathogenic gram positive strain, Staphylococcus aureus is interesting as a model system due to possible development of respective biosensors for prevention and detection of the pathogenic strain methicillin resistant Staphylococcus aureus (MRSA) and further as a study for bio-machine interfacing. Self Assembled Monolayers (SAM) with engineered surfaces of linear thiols on Au(111) were used as the substrate. Sub cultured S. aureus were used for the analysis. The SAM layered surfaces were dipped in 2 -- 4 Log/ml S. aureus solution. Subsequent surface adhesion at different bacterial dilutions on surfaces will be discussed, and correlated with quantitative and qualitative adhesion properties of bacteria on the engineered SAM surfaces. The bacteria adhered SAM surfaces were investigated using intermittent contact, noncontact, lateral force and contact modes of Atomic Force Microscopy (AFM).

  5. CD and NMR conformational studies of a peptide encompassing the Mid Loop interface of Ship2-Sam.

    PubMed

    Mercurio, Flavia A; Scognamiglio, Pasqualina L; Di Natale, Concetta; Marasco, Daniela; Pellecchia, Maurizio; Leone, Marilisa

    2014-11-01

    The lipid phosphatase Ship2 is a protein that intervenes in several diseases such as diabetes, cancer, neurodegeneration, and atherosclerosis. It is made up of a catalytic domain and several protein docking modules such as a C-terminal Sam (Sterile alpha motif) domain. The Sam domain of Ship2 (Ship2-Sam) binds to the Sam domains of the EphA2 receptor (EphA2-Sam) and the PI3K effector protein Arap3 (Arap3-Sam). These heterotypic Sam-Sam interactions occur through formation of dimers presenting the canonical "Mid Loop/End Helix" binding mode. The central region of Ship2-Sam, spanning the C-terminal end of α2, the α3 and α4 helices together with the α2α3 and α3α4 interhelical loops, forms the Mid Loop surface that is needed to bind partners Sam domains. A peptide encompassing most of the Ship2-Sam Mid Loop interface (Shiptide) capable of binding to both EphA2-Sam and Arap3-Sam, was previously identified. Here we investigated the conformational features of this peptide, through solution CD and NMR studies in different conditions. These studies reveal that the peptide is highly flexible in aqueous buffer, while it adopts a helical conformation in presence of 2,2,2-trifluoroethanol. The discovered structural insights and in particular the identification of a helical motif, may lead to the design of more constrained and possibly cell permeable Shiptide analogs that could work as efficient antagonists of Ship2-Sam heterotypic interactions and embrace therapeutic applications.

  6. Bringing a Chemical Laboratory Named Sam to Mars on the 2011 Curiosity Rover

    NASA Astrophysics Data System (ADS)

    Mahaffy, P. R.; Bleacher, L.; Jones, A.; Atreya, S. K.; Manning, H. L.; Cabane, M.; Webster, C. R.; Sam Team

    2010-12-01

    Introduction: An important goal of upcoming missions to Mars is to understand if life could have developed there. The task of the Sample Analysis at Mars (SAM) suite of instruments [1] and the other Curiosity investigations [2] is to move us steadily toward that goal with an assessment of the habitability of our neighboring planet through a series of chemical and geological measurements. SAM is designed to search for organic compounds and inorganic volatiles and measure isotope ratios. Other instruments on Curiosity will provide elemental analysis and identify minerals. SAM will analyze both atmospheric samples and gases evolved from powdered rocks that may have formed billions of years ago with Curiosity providing access to interesting sites scouted by orbiting cameras and spectrometers. SAM Instrument Suite: SAM’s instruments are a Quadrupole Mass Spectrometer (QMS), a 6-column Gas Chromatograph (GC), and a 2-channel Tunable Laser Spectrometer (TLS). SAM can identify organic compounds in Mars rocks to sub-ppb sensitivity and secure precise isotope ratios for C, H, and O in carbon dioxide and water and measure trace levels of methane and its carbon 13 isotope. The SAM gas processing system consists of valves, heaters, pressure sensors, gas scrubbers and getters, traps, and gas tanks used for calibration or combustion experiments [2]. A variety of calibrant compounds interior and exterior to SAM will allow the science and engineering teams to assess SAM’s performance. SAM has been calibrated and tested in a Mars-like environment. Keeping Educators and the Public Informed: The Education and Public Outreach (EPO) goals of the SAM team are to make this complex chemical laboratory and its data widely available to educators, students, and the public. Formal education activities include developing templates for professional development workshops for educators to teach them about SAM and Curiosity, incorporating data into Mars Student Data Teams, and writing articles

  7. A role of the SAM domain in EphA2 receptor activation

    PubMed Central

    Shi, Xiaojun; Hapiak, Vera; Zheng, Ji; Muller-Greven, Jeannine; Bowman, Deanna; Lingerak, Ryan; Buck, Matthias; Wang, Bing-Cheng; Smith, Adam W.

    2017-01-01

    Among the 20 subfamilies of protein receptor tyrosine kinases (RTKs), Eph receptors are unique in possessing a sterile alpha motif (SAM domain) at their C-terminal ends. However, the functions of SAM domains in Eph receptors remain elusive. Here we report on a combined cell biology and quantitative fluorescence study to investigate the role of the SAM domain in EphA2 function. We observed elevated tyrosine autophosphorylation levels upon deletion of the EphA2 SAM domain (EphA2ΔS) in DU145 and PC3 prostate cancer cells and a skin tumor cell line derived from EphA1/A2 knockout mice. These results suggest that SAM domain deletion induced constitutive activation of EphA2 kinase activity. In order to explain these effects, we applied fluorescence correlation spectroscopy to investigate the lateral molecular organization of EphA2. Our results indicate that SAM domain deletion (EphA2ΔS-GFP) increases oligomerization compared to the full length receptor (EphA2FL-GFP). Stimulation with ephrinA1, a ligand for EphA2, induced further oligomerization and activation of EphA2FL-GFP. The SAM domain deletion mutant, EphA2ΔS-GFP, also underwent further oligomerization upon ephrinA1 stimulation, but the oligomers were larger than those observed for EphA2FL-GFP. Based on these results, we conclude that the EphA2 SAM domain inhibits kinase activity by reducing receptor oligomerization. PMID:28338017

  8. The Combustion Experiment on the Sample Analysis at Mars (SAM) Instrument Suite on the Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Stern, J. C.; Malespin, C. A.; Eigenbrode, J. L.; Graham, H. V.; Archer, P. D., Jr.; Brunner, A. E.; Freissinet, C.; Franz, H. B.; Fuentes, J.; Glavin, D. P.; Leshin, L. A.; Mahaffy, P. R.; McAdam, A. C.; Ming, D. W.; Navvaro-Gonzales, R.; Niles, P. B.; Steele, A.

    2014-01-01

    The combustion experiment on the Sample Analysis at Mars (SAM) suite on Curiosity will heat a sample of Mars regolith in the presence of oxygen and measure composition of the evolved gases using quadrupole mass spectrometry (QMS) and tunable laser spectrometry (TLS). QMS will enable detection of combustion products such as CO, CO2, NO, and other oxidized species, while TLS will enable precise measurements of the abundance and carbon isotopic composition (delta(sup 13)C) of the evolved CO2 and hydrogen isotopic composition (deltaD) of H2O. SAM will perform a two-step combustion to isolate combustible materials below approx.550 C and above approx.550 C. The combustion experiment on SAM, if properly designed and executed, has the potential to answer multiple questions regarding the origins of volatiles seen thus far in SAM evolved gas analysis (EGA) on Mars. Constraints imposed by SAM and MSL time and power resources, as well as SAM consumables (oxygen gas), will limit the number of SAM combustion experiments, so it is imperative to design an experiment targeting the most pressing science questions. Low temperature combustion experiments will primarily target the quantification of carbon (and nitrogen) contributed by SAM wet chemistry reagants MTBSTFA (N-Methyl-N-tert-butyldimethylsilyltrifluoroacetamide) and DMF (Dimethylformamide), which have been identified in the background of blank and sample runs and may adsorb to the sample while the cup is in the Sample Manipulation System (SMS). In addition, differences between the sample and "blank" may yield information regarding abundance and delta(sup 13)C of bulk (both organic and inorganic) martian carbon. High temperature combustion experiments primarily aim to detect refractory organic matter, if present in Cumberland fines, as well as address the question of quantification and deltaD value of water evolution associated with hydroxyl hydrogen in clay minerals.

  9. Identification of trans-acting factors regulating SamDC expression in Oryza sativa

    SciTech Connect

    Basu, Supratim; Roychoudhury, Aryadeep; Sengupta, Dibyendu N.

    2014-03-07

    Highlights: • Identification of cis elements responsible for SamDC expression by in silico analysis. • qPCR analysis of SamDC expression to abiotic and biotic stress treatments. • Detection of SamDC regulators using identified cis-elements as probe by EMSA. • Southwestern Blot analysis to predict the size of the trans-acting factors. - Abstract: Abiotic stress affects the growth and productivity of crop plants; to cope with the adverse environmental conditions, plants have developed efficient defense machinery comprising of antioxidants like phenolics and flavonoids, and osmolytes like polyamines. SamDC is a key enzyme in the polyamine biosynthesis pathway in plants. In our present communication we have done in silico analysis of the promoter region of SamDC to look for the presence of different cis-regulatory elements contributing to its expression. Based on the presence of different cis-regulatory elements we completed comparative analysis of SamDC gene expression in rice lamina of IR-29 and Nonabokra by qPCR in response to the abiotic stress treatments of salinity, drought, cold and the biotic stress treatments of ABA and light. Additionally, to explore the role of the cis-regulatory elements in regulating the expression of SamDC gene in plants we comparatively analyzed the binding of rice nuclear proteins prepared from IR-29 and Nonabokra undergoing various stress treatments. The intensity of the complex formed was low and inducible in IR-29 in contrast to Nonabokra. Southwestern blot analysis helped in predicting the size of the trans-acting factors binding to these cis-elements. To our knowledge this is the first report on the comprehensive analysis of SamDC gene expression in rice and identification of the trans-acting factors regulating its expression.

  10. Fast and slow responses of Southern Ocean sea surface temperature to SAM in coupled climate models

    NASA Astrophysics Data System (ADS)

    Kostov, Yavor; Marshall, John; Hausmann, Ute; Armour, Kyle C.; Ferreira, David; Holland, Marika M.

    2017-03-01

    We investigate how sea surface temperatures (SSTs) around Antarctica respond to the Southern Annular Mode (SAM) on multiple timescales. To that end we examine the relationship between SAM and SST within unperturbed preindustrial control simulations of coupled general circulation models (GCMs) included in the Climate Modeling Intercomparison Project phase 5 (CMIP5). We develop a technique to extract the response of the Southern Ocean SST (55°S-70°S) to a hypothetical step increase in the SAM index. We demonstrate that in many GCMs, the expected SST step response function is nonmonotonic in time. Following a shift to a positive SAM anomaly, an initial cooling regime can transition into surface warming around Antarctica. However, there are large differences across the CMIP5 ensemble. In some models the step response function never changes sign and cooling persists, while in other GCMs the SST anomaly crosses over from negative to positive values only 3 years after a step increase in the SAM. This intermodel diversity can be related to differences in the models' climatological thermal ocean stratification in the region of seasonal sea ice around Antarctica. Exploiting this relationship, we use observational data for the time-mean meridional and vertical temperature gradients to constrain the real Southern Ocean response to SAM on fast and slow timescales.

  11. Contribution of sams-1 and pmt-1 to lipid homoeostasis in adult Caenorhabditis elegans.

    PubMed

    Li, Yingxiu; Na, Keun; Lee, Hyoung-Joo; Lee, Eun-Young; Paik, Young-Ki

    2011-05-01

    Accumulation of lipids inside the cell is primarily caused by disorders of lipid metabolism. S-adenosylmethionine synthetase (SAMS) produces SAM, an important methyl donor in various phospholipid methyltransferase reactions catalysed by phosphoethanolamine N-methyltransferase (PMT-1). A gel-based, quantitative proteomic analysis of the RNA interference (RNAi)-mediated inactivation of the pod-2 gene, which encodes acetyl-CoA carboxylase, showed a substantial down-regulation of SAMS-1. Consequently, RNAi of either sams-1 or pmt-1 caused a significant increase in lipid droplet size in the intestine of Caenorhabditis elegans. Lipid droplets exhibited increased triacylglycerol (TG) and decreased phosphatidylcholine (PC) levels, suggesting a reciprocal relationship between TG and PC regulation. These lipid-associated phenotypes were rescued by choline feeding. Among the five fat metabolism-related genes examined, two genes were highly induced by inactivation of sams-1 or pmt-1: pod-2 and stearoyl-CoA desaturase (fat-7). Thus, both SAMS-1 and PMT-1 were shown to contribute to the homoeostasis of TG and PC levels in C. elegans, which would provide an important survival strategy under harsh environmental conditions.

  12. Sam68 Is Required for DNA Damage Responses via Regulating Poly(ADP-ribosyl)ation

    PubMed Central

    Hodgson, Andrea; Wier, Eric M.; Wen, Matthew G.; Kamenyeva, Olena; Xia, Xue; Koo, Lily Y.

    2016-01-01

    The rapid and robust synthesis of polymers of adenosine diphosphate (ADP)-ribose (PAR) chains, primarily catalyzed by poly(ADP-ribose) polymerase 1 (PARP1), is crucial for cellular responses to DNA damage. However, the precise mechanisms through which PARP1 is activated and PAR is robustly synthesized are not fully understood. Here, we identified Src-associated substrate during mitosis of 68 kDa (Sam68) as a novel signaling molecule in DNA damage responses (DDRs). In the absence of Sam68, DNA damage-triggered PAR production and PAR-dependent DNA repair signaling were dramatically diminished. With serial cellular and biochemical assays, we demonstrated that Sam68 is recruited to and significantly overlaps with PARP1 at DNA lesions and that the interaction between Sam68 and PARP1 is crucial for DNA damage-initiated and PARP1-conferred PAR production. Utilizing cell lines and knockout mice, we illustrated that Sam68-deleted cells and animals are hypersensitive to genotoxicity caused by DNA-damaging agents. Together, our findings suggest that Sam68 plays a crucial role in DDR via regulating DNA damage-initiated PAR production. PMID:27635653

  13. Non-canonical active site architecture of the radical SAM thiamin pyrimidine synthase

    NASA Astrophysics Data System (ADS)

    Fenwick, Michael K.; Mehta, Angad P.; Zhang, Yang; Abdelwahed, Sameh H.; Begley, Tadhg P.; Ealick, Steven E.

    2015-03-01

    Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to generate a 5‧-deoxyadenosyl radical. Canonical radical SAM enzymes are characterized by a β-barrel-like fold and SAM anchors to the differentiated iron of the cluster, which is located near the amino terminus and within the β-barrel, through its amino and carboxylate groups. Here we show that ThiC, the thiamin pyrimidine synthase in plants and bacteria, contains a tethered cluster-binding domain at its carboxy terminus that moves in and out of the active site during catalysis. In contrast to canonical radical SAM enzymes, we predict that SAM anchors to an additional active site metal through its amino and carboxylate groups. Superimposition of the catalytic domains of ThiC and glutamate mutase shows that these two enzymes share similar active site architectures, thus providing strong evidence for an evolutionary link between the radical SAM and adenosylcobalamin-dependent enzyme superfamilies.

  14. CNK and HYP form a discrete dimer by their SAM domains to mediate RAF kinase signaling.

    PubMed

    Rajakulendran, Thanashan; Sahmi, Malha; Kurinov, Igor; Tyers, Mike; Therrien, Marc; Sicheri, Frank

    2008-02-26

    RAF kinase functions in the mitogen-activated protein kinase (MAPK) pathway to transmit growth signals to the downstream kinases MEK and ERK. Activation of RAF catalytic activity is facilitated by a regulatory complex comprising the proteins CNK (Connector enhancer of KSR), HYP (Hyphen), and KSR (Kinase Suppressor of Ras). The sterile alpha-motif (SAM) domain found in both CNK and HYP plays an essential role in complex formation. Here, we have determined the x-ray crystal structure of the SAM domain of CNK in complex with the SAM domain of HYP. The structure reveals a single-junction SAM domain dimer of 1:1 stoichiometry in which the binding mode is a variation of polymeric SAM domain interactions. Through in vitro and in vivo mutational analyses, we show that the specific mode of dimerization revealed by the crystal structure is essential for RAF signaling and facilitates the recruitment of KSR to form the CNK/HYP/KSR regulatory complex. We present two docking-site models to account for how SAM domain dimerization might influence the formation of a higher-order CNK/HYP/KSR complex.

  15. Non-canonical active site architecture of the radical SAM thiamin pyrimidine synthase

    DOE PAGES

    Fenwick, Michael K.; Mehta, Angad P.; Zhang, Yang; ...

    2015-03-27

    Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to generate a 5'-deoxyadenosyl radical. Canonical radical SAM enzymes are characterized by a β-barrel-like fold and SAM anchors to the differentiated iron of the cluster, which is located near the amino terminus and within the β-barrel, through its amino and carboxylate groups. Here we show that ThiC, the thiamin pyrimidine synthase in plants and bacteria, contains a tethered cluster-binding domain at its carboxy terminus that moves in and out of the active site during catalysis. In contrast to canonical radical SAM enzymes, we predict that SAM anchors to an additional active sitemore » metal through its amino and carboxylate groups. Superimposition of the catalytic domains of ThiC and glutamate mutase shows that these two enzymes share similar active site architectures, thus providing strong evidence for an evolutionary link between the radical SAM and adenosylcobalamin-dependent enzyme superfamilies.« less

  16. SAM-Like Evolved Gas Analyses of Phyllosilicate Minerals and Applications to SAM Analyses of the Sheepbed Mudstone, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Franz, H. B.; Mahaffy, P. R.; Eigenbrode, J. L.; Stern, J. C.; Brunner, B.; Sutter, B.; Archer, P. D.; Ming , D. W.; Morris, R. V.; Bish, D. L.; Atreya, S. K.

    2014-01-01

    While in Yellowknife Bay, the Mars Science Laboratory Curiosity rover collected two drilled samples, John Klein (hereafter "JK") and Cumberland ("CB"), from the Sheepbed mudstone, as well as a scooped sample from the Rocknest aeolian bedform ("RN"). These samples were sieved by Curiosity's sample processing system and then several subsamples of these materials were delivered to the Sample Analysis at Mars (SAM) instrument suite and the CheMin X-ray diffraction/X-ray fluorescence instrument. CheMin provided the first in situ X-ray diffraction-based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., Fe-saponite) and comprise 20 wt% of the mudstone samples [1]. SAM's evolved gas analysis (EGA) mass spectrometry analyses of JK and CB subsamples, as well as RN subsamples, detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, OCS, CS2 and other trace gases evolved during pyrolysis. The identity of evolved gases and temperature( s) of evolution can augment mineral detection by CheMin and place constraints on trace volatile-bearing phases present below the CheMin detection limit or those phases difficult to characterize with XRD (e.g., X-ray amorphous phases). Here we will focus on the SAM H2O data, in the context of CheMin analyses, and comparisons to laboratory SAM-like analyses of several phyllosilicate minerals including smectites.

  17. Sam68 marks the transcriptionally active stages of spermatogenesis and modulates alternative splicing in male germ cells

    PubMed Central

    Paronetto, Maria Paola; Messina, Valeria; Barchi, Marco; Geremia, Raffaele; Richard, Stéphane; Sette, Claudio

    2011-01-01

    Sam68 plays an essential role in mouse spermatogenesis and male fertility. Herein, we report an interaction between Sam68 and the phosphorylated forms of the RNA polymerase II (RNAPII) in meiotic spermatocytes. RNase treatment decreased but did not abolish the interaction, consistently with in vitro binding of RNAPII to the Sam68 carboxyl-terminal region. Sam68 retention in the spermatocyte nucleus was dependent on the integrity of cellular RNAs, suggesting that the protein is recruited to transcriptionally active chromatin. Mouse knockout models characterized by stage-specific arrest of spermatogenesis and staining with the phosphorylated form of RNAPII documented that Sam68 expression is confined to the transcriptionally active stages of spermatogenesis. Furthermore, Sam68 associates with splicing regulators in germ cells and we report that alternative splicing of Sgce exon 8 is regulated in a Sam68-dependent manner during spermatogenesis. RNA and chromatin crosslink immunoprecipitation experiments showed that Sam68 binds in vivo to sequences surrounding the intron 7/exon 8 boundary, thereby affecting the recruitment of the phosphorylated RNAPII and of the general splicing factor U2AF65. These results suggest that Sam68 regulates alternative splicing at transcriptionally active sites in differentiating germ cells and provide new insights into the regulation of Sam68 expression during spermatogenesis. PMID:21355037

  18. Structural analysis of loci involved in pSAM2 site-specific integration in Streptomyces.

    PubMed

    Boccard, F; Smokvina, T; Pernodet, J L; Friedmann, A; Guérineau, M

    1989-01-01

    pSAM2 is an 11-kb plasmid integrated in the Streptomyces ambofaciens ATCC23877 and ATCC15154 genomes and found additionally as a free replicon in an uv derivative. After transfer into S. ambofaciens DSM40697 (devoid of pSAM2) or into Streptomyces lividans, specific integration of pSAM2 occurred very efficiently. A 58-bp sequence (att) present in both pSAM2 (attP) and S. ambofaciens strain DSM40697 (attB) attachment regions is found at the boundaries (attL and attR) of integrated pSAM2 in S. ambofaciens strain ATCC23877. The S. lividans chromosomal integration zone contained an imperfectly conserved att sequence (attB), and the integration event of pSAM2 was located within a 49-bp sequence of attB. Only one primary functional attB sequence was present in the S. lividans or S. ambofaciens DSM40697 total DNA. The integration zone of S. lividans hybridized with the integration zone of S. ambofaciens DSM40697. The two integration zones were homologous only to the right side of the att sequence. The conserved region contained an open reading frame (ORF A) with a stop codon located 99 bp from the attB sequence in both strains. S. ambofaciens DSM40697 contained DNA sequences related to pSAM2 on the left side of the att site. The att sequence was included in a region conserved in Streptomyces antibioticus, Streptomyces actuosus, Streptomyces bikiniensis, Streptomyces coelicolor, Streptomyces glaucescens, and Streptomyces parvulus. Site-specific integration of a pSAM2 derivative was characterized in another unrelated strain, Streptomyces griseofuscus. This strain contained an imperfectly conserved 58-bp attB sequence, and the integration event took place within a 45-bp sequence of attB. Site-specific integration of pSAM2 in three nonrelated Streptomyces strains suggests the wide host range of pSAM2 integration in Streptomyces.

  19. Aluminide coatings

    SciTech Connect

    Henager, Jr; Charles, H; Shin, Yongsoon; Samuels, William D

    2009-08-18

    Disclosed herein are aluminide coatings. In one embodiment coatings are used as a barrier coating to protect a metal substrate, such as a steel or a superalloy, from various chemical environments, including oxidizing, reducing and/or sulfidizing conditions. In addition, the disclosed coatings can be used, for example, to prevent the substantial diffusion of various elements, such as chromium, at elevated service temperatures. Related methods for preparing protective coatings on metal substrates are also described.

  20. COATED ALLOYS

    DOEpatents

    Harman, C.G.; O'Bannon, L.S.

    1958-07-15

    A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

  1. Organosilane self-assembled layers (SAMs) and hybrid silicate magnesium-rich primers for the corrosion protection of aluminum alloy 2024 T3

    NASA Astrophysics Data System (ADS)

    Wang, Duhua

    Although current chromate coatings function very well in corrosion protection for aircraft alloys, such as aluminum alloy 2024 T3, the U.S. Environmental Protection Agency is planning to totally ban the use of chromates as coating materials in the next decade or so because of their extremely toxic effect. For this purpose, both self-assembled layers and silicate magnesium-rich primers were tested to provide the corrosion protection for aluminum alloy. The long-term goal of this research is to develop a coating system to replace the current chromate coating for aircraft corrosion protection. Aluminum alloy 2024 T3 substrates were modified with self-assembled monolayer or multilayer thin films from different alkylsilane compounds. Mono-functional silanes, such as octadecyltrichlorosilane (C18SiCl3), can form a mixed hydrophobic monolayer or multilayer thin film on the aluminum oxide surface to provide a barrier to water and other electrolytes, so the corrosion resistance of the SAMs modified surface was increased significantly. On the other hand, the bi-functional silane self-assembly could attach the aluminum surface through the silicon headgroup while using its functional tailgroup to chemically bond the polymer coating, thus improving the adhesion between the aluminum substrate and coating substantially, and seems to contribute more to corrosion protection of aluminum substrate. Organosilanes were also combined with tetraethyl orthosilicate (TEOS) in propel ratios to form a sol-gel binder to make silicate magnesium-rich primers. Analogue to the inorganic zinc-rich coatings, the silicate magnesium-rich primers also showed excellent adhesion and solvent resistance. The sacrificial magnesium pigments and the chemically inert silicate binder both contribute to the anti-corrosion properties. Future studies will be focused on the formula optimization for better toughness, chemical resistance and anticorrosion performance.

  2. Antibody binding to p-Si using LANL SAM chemistry

    SciTech Connect

    Anderson, Aaron S

    2010-12-06

    This NMSBA-sponsored project involves the attachment of antibodies to polymeric silicon (p-Si) surfaces, with the ultimate goal of attaching antibodies to nanowires for Vista Therapeutics, Inc. (Santa Fe, NM). This presentation describes the functionalization of p-Si surfaces. the activation of terminal carboxylates on these surfaces, the conjugation of antibodies, and the analyses undertaken at each step. The results of this work show that antibody conjugation is possible on p-Si coatings using the well-known EDC/NHS activation chemistry.

  3. SAM Sample preparation and its impact on the detection of organic compounds on Mars

    NASA Astrophysics Data System (ADS)

    Buch, Arnaud; Szopa, Cyril; Coll, Patrice; Freissinet, Caroline; Glavin, Daniel; Belmahdi, Imene; François, Pascaline; Millan, Maeva; Eigenbrode, Jennifer; navarro, Rafael; Stern, Jennifer; Pinnick, Veronica; Coscia, David; Teinturier, Samuel; Miller, Kristen; Summons, Roger; Mahaffy, Paul

    2014-05-01

    The wet chemistry experiments on the Sample Analysis at Mars (SAM) [1] experiment in the Curiosity rover of the Mars Science Laboratory mission supports extraction of polar organic compounds from solid samples that improves their detection either by increasing the release of chemical species from solid sample matrices, or by changing their chemical structure to make compounds more amenable to gas chromatography mass spectrometry (GCMS). The wet chemistry approach provides an alternative to the nominal inert-thermal desorption/pyrolysis analytical protocol used by SAM [1] that is more aptly suited for polar components. SAM, includes two different wet chemistry experiments: MTBSTFA derivatization [2-3] and TMAH thermochemolysis [4]. Here we report on the nature of the MTBSTFA derivatization experiment on SAM, the detection of MTBSTFA products in the SAM evolved gas analysis and GCMS experiments, and the implications of this detection. Solid sample were heated up to approximately 840°C at a rate of 35°C/min under He flow. For GC analyses, the majority of the gas released was trapped on a hydrocarbon trap (Tenax®) over a specific temperature range. Adsorbed volatiles on the GC injection trap (IT) were then released into the GC column (CLP-MXT 30m x 0.25mm x 0.25µm) by rapidly heating the IT to 300°C. Then, in order better understand the part of compounds detected coming from internal reaction we have performed several lab experiments to mimic the SAM device. We have investigated the thermal degradation of Tenax®, and possible interaction with MTBSTFA and perchlorate in the SAM trap (Tenax®) to better constrain interpretations of SAM results on Mars. References: [1] Mahaffy, P. et al. (2012) Space Sci Rev, 170, 401-478. [2] Buch, A. et al. (2009) J chrom. A, 43, 143-151. [3] Stalport, F. et al. (2012) Planet. Space Sci. 67: 1-13 [4] Geffroy-Rodier, C. et al. (2009) JAAP, 85, 454-459. Acknowledgements: SAM-GC team acknowledges support from the French Space Agency

  4. Carbon-sulfur bond-forming reaction catalysed by the radical SAM enzyme HydE

    NASA Astrophysics Data System (ADS)

    Rohac, Roman; Amara, Patricia; Benjdia, Alhosna; Martin, Lydie; Ruffié, Pauline; Favier, Adrien; Berteau, Olivier; Mouesca, Jean-Marie; Fontecilla-Camps, Juan C.; Nicolet, Yvain

    2016-05-01

    Carbon-sulfur bond formation at aliphatic positions is a challenging reaction that is performed efficiently by radical S-adenosyl-L-methionine (SAM) enzymes. Here we report that 1,3-thiazolidines can act as ligands and substrates for the radical SAM enzyme HydE, which is involved in the assembly of the active site of [FeFe]-hydrogenase. Using X-ray crystallography, in vitro assays and NMR spectroscopy we identified a radical-based reaction mechanism that is best described as the formation of a C-centred radical that concomitantly attacks the sulfur atom of a thioether. To the best of our knowledge, this is the first example of a radical SAM enzyme that reacts directly on a sulfur atom instead of abstracting a hydrogen atom. Using theoretical calculations based on our high-resolution structures we followed the evolution of the electronic structure from SAM through to the formation of S-adenosyl-L-cysteine. Our results suggest that, at least in this case, the widely proposed and highly reactive 5‧-deoxyadenosyl radical species that triggers the reaction in radical SAM enzymes is not an isolable intermediate.

  5. The relative influence of ENSO and SAM on Antarctic Peninsula climate

    NASA Astrophysics Data System (ADS)

    Clem, Kyle R.; Renwick, James A.; McGregor, James; Fogt, Ryan L.

    2016-08-01

    Recent warming of the Antarctic Peninsula during austral autumn, winter, and spring has been linked to sea surface temperature (SST) trends in the tropical Pacific and tropical Atlantic, while warming of the northeast Peninsula during summer has been linked to a strengthening of westerly winds traversing the Peninsula associated with a positive trend in the Southern Annular Mode (SAM). Here we demonstrate that circulation changes associated with the SAM dominate interannual temperature variability across the entire Antarctic Peninsula during both summer and autumn, while relationships with tropical Pacific SST variability associated with the El Niño-Southern Oscillation (ENSO) are strongest and statistically significant primarily during winter and spring only. We find the ENSO-Peninsula temperature relationship during autumn to be weak on interannual time scales and regional circulation anomalies associated with the SAM more important for interannual temperature variability across the Peninsula during autumn. Consistent with previous studies, western Peninsula temperatures during autumn, winter, and spring are closely tied to changes in the Amundsen Sea Low (ASL) and associated meridional wind anomalies. The interannual variability of ASL depth is most strongly correlated with the SAM index during autumn, while the ENSO relationship is strongest during winter and spring. Investigation of western and northeast Peninsula temperatures separately reveals that interannual variability of northeast Peninsula temperatures is primarily sensitive to zonal wind anomalies crossing the Peninsula and resultant leeside adiabatic warming rather than to meridional wind anomalies, which is closely tied to variability in the zonal portion of the SAM pattern.

  6. SAM-FS: LSC's New Solaris-Based Storage Management Product

    NASA Technical Reports Server (NTRS)

    Angell, Kent

    1996-01-01

    SAM-FS is a full featured hierarchical storage management (HSM) device that operates as a file system on Solaris-based machines. The SAM-FS file system provides the user with all of the standard UNIX system utilities and calls, and adds some new commands, i.e. archive, release, stage, sls, sfind, and a family of maintenance commands. The system also offers enhancements such as high performance virtual disk read and write, control of the disk through an extent array, and the ability to dynamically allocate block size. SAM-FS provides 'archive sets' which are groupings of data to be copied to secondary storage. In practice, as soon as a file is written to disk, SAM-FS will make copies onto secondary media. SAM-FS is a scalable storage management system. The system can manage millions of files per system, though this is limited today by the speed of UNIX and its utilities. In the future, a new search algorithm will be implemented that will remove logical and performance restrictions on the number of files managed.

  7. Oxygen Attachment on Alkanethiolate SAMs Induced by Low-Energy Electron Irradiation

    PubMed Central

    Massey, Sylvain; Bass, Andrew D.; Steffenhagen, Marie; Sanche, Léon

    2013-01-01

    Reactions of 18O2 with self-assembled monolayer (SAM) films of 1-dodecanethiol, 1-octadecanethiol, 1-butanethiol, and benzyl mercaptan chemisorbed on gold, were studied by the electron stimulated desorption (ESD) of anionic fragments over the incident electron energy range 2–20 eV. Dosing the SAMs with 18O2 at 50 K, results in the ESD of 18O− and 18OH−. Electron irradiation of samples prior to 18O2 deposition demonstrates that intensity of subsequent 18O− and 18OH− desorption signals increase with electron fluence and that absent electron pre-irradiation, no 18O− and 18OH− ESD signals are observed, since oxygen is unable to bind to the SAMs. A minimum incident electron energy of 6–7 eV is required to initiate the binding of 18O2 to the SAMs. O2 binding is proposed to proceed by the formation of CHx−1• radicals via resonant dissociative electron attachment and non-resonant C–H dissociation processes. The weaker signals of 18O− and 18OH− from short-chain SAMs are related to the latter’s resistance to electron induced damage, due to the charge-image dipole quenching and electron delocalization. Comparison between the present results and those for DNA oligonucleotides self-assembled on Au [Mirsaleh-Kohan, N. et al. J. Chem. Phys. 2012, 136, 235104] indicates that the oxygen binding mechanism is common to both systems. PMID:23537075

  8. ER residency of the ceramide phosphoethanolamine synthase SMSr relies on homotypic oligomerization mediated by its SAM domain

    PubMed Central

    Cabukusta, Birol; Kol, Matthijs; Kneller, Laura; Hilderink, Angelika; Bickert, Andreas; Mina, John G. M.; Korneev, Sergei; Holthuis, Joost C. M.

    2017-01-01

    SMSr/SAMD8 is an ER-resident ceramide phosphoethanolamine synthase with a critical role in controlling ER ceramides and suppressing ceramide-induced apoptosis in cultured cells. SMSr-mediated ceramide homeostasis relies on the enzyme’s catalytic activity as well as on its N-terminal sterile α-motif or SAM domain. Here we report that SMSr-SAM is structurally and functionally related to the SAM domain of diacylglycerol kinase DGKδ, a central regulator of lipid signaling at the plasma membrane. Native gel electrophoresis indicates that both SAM domains form homotypic oligomers. Chemical crosslinking studies show that SMSr self-associates into ER-resident trimers and hexamers that resemble the helical oligomers formed by DGKδ-SAM. Residues critical for DGKδ-SAM oligomerization are conserved in SMSr-SAM and their substitution causes a dissociation of SMSr oligomers as well as a partial redistribution of the enzyme to the Golgi. Conversely, treatment of cells with curcumin, a drug disrupting ceramide and Ca2+ homeostasis in the ER, stabilizes SMSr oligomers and promotes retention of the enzyme in the ER. Our data provide first demonstration of a multi-pass membrane protein that undergoes homotypic oligomerization via its SAM domain and indicate that SAM-mediated self-assembly of SMSr is required for efficient retention of the enzyme in the ER. PMID:28120887

  9. Characterization of pra, a gene for replication control in pSAM2, the integrating element of Streptomyces ambofaciens.

    PubMed

    Sezonov, G; Hagège, J; Pernodet, J L; Friedmann, A; Guérineau, M

    1995-08-01

    pSAM2 is a genetic element found integrated in Streptomyces ambofaciens (B2) and additionally in a replicating form in two mutants B3 and B4. The presence of the pSAM2 replicating form in these mutants was the result of mutations located on pSAM2 in the pra locus, named pra3 and pra4, respectively. The pra gene is not directly involved in replication, but its inactivation led to the disappearance of the pSAM2 free form; therefore, it was considered as a replication regulator. The pra3 and pra4 mutations were located in the pra promoter and were shown to be point substitutions that increase the promoter strength. The replication regulator role of pra was demonstrated by the fact that its constitutive expression in cells harbouring pSAM2B2, which is normally only integrated, led to the appearance of the pSAM2 replicating form. Northern analysis showed that the pra gene transcript can be detected only for the replicating mutants B3 and B4 and that the three adjacent genes korSA, pra and traSA were transcribed separately. As replication of pSAM2 is not needed for its maintenance but is an indispensable stage of its transfer, the pra gene, described formally as an activator of pSAM2 replication, is patently involved in pSAM2 transfer.

  10. The crystal structure of a novel SAM-dependent methyltransferase PH1915 from Pyrococcus horikoshii.

    SciTech Connect

    Sun, W.; Xu, X.; Pavlova, M.; Edwards, A.; Joachimiak, A.; Savchenko, A.; Christendat, D.; Biosciences Division; Univ. of Toronto; Univ. Health Network

    2005-01-01

    The S-adenosyl-L-methionine (SAM)-dependent methyltransferases represent a diverse and biologically important class of enzymes. These enzymes utilize the ubiquitous methyl donor SAM as a cofactor to methylate proteins, small molecules, lipids, and nucleic acids. Here we present the crystal structure of PH1915 from Pyrococcus horikoshii OT3, a predicted SAM-dependent methyltransferase. This protein belongs to the Cluster of Orthologous Group 1092, and the presented crystal structure is the first representative structure of this protein family. Based on sequence and 3D structure analysis, we have made valuable functional insights that will facilitate further studies for characterizing this group of proteins. Specifically, we propose that PH1915 and its orthologs are rRNA- or tRNA-specific methyltransferases.

  11. SPASM and Twitch Domains in S-Adenosylmethionine (SAM) Radical Enzymes*

    PubMed Central

    Grell, Tsehai A. J.; Goldman, Peter J.; Drennan, Catherine L.

    2015-01-01

    S-Adenosylmethionine (SAM, also known as AdoMet) radical enzymes use SAM and a [4Fe-4S] cluster to catalyze a diverse array of reactions. They adopt a partial triose-phosphate isomerase (TIM) barrel fold with N- and C-terminal extensions that tailor the structure of the enzyme to its specific function. One extension, termed a SPASM domain, binds two auxiliary [4Fe-4S] clusters and is present within peptide-modifying enzymes. The first structure of a SPASM-containing enzyme, anaerobic sulfatase-maturating enzyme (anSME), revealed unexpected similarities to two non-SPASM proteins, butirosin biosynthetic enzyme 2-deoxy-scyllo-inosamine dehydrogenase (BtrN) and molybdenum cofactor biosynthetic enzyme (MoaA). The latter two enzymes bind one auxiliary cluster and exhibit a partial SPASM motif, coined a Twitch domain. Here we review the structure and function of auxiliary cluster domains within the SAM radical enzyme superfamily. PMID:25477505

  12. Distributed processing and analysis of physics data in the D0 SAM system at Fermilab

    SciTech Connect

    Igor V. Terekhov

    2001-08-30

    SAM (Sequential Access through Meta-data) is the data access system for the D0 high energy physics (HEP) experiment at Fermilab. The system is being developed and used to handle the Petabyte-scale experiment data. The D0 applications, like virtually all HEP applications, are data-intensive, which poses special problems for the data management and job control facilities in the distributed environment. The fundamental problem is to bring the user applications and the data together, and SAM attacks the problems from both sides. First, we describe how the system moves the data through the distributed disk cache. Second, we describe how SAM interacts with the batch system to synchronize parallel user jobs with the data availability. All the design solutions herein have been implemented in a real system that handles the mission-critical data of the D0 experiment; thus, we present our work from the standpoint of real experience.

  13. Bringing a Chemical Laboratory Named Sam to Mars on the 2011 Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Mahaffy, P. R.; Bleacher, L.; Jones, A.; Conrad, P. G.; Cabane, M.; Webster, C. R.; Atreya, S. A.; Manning, H.

    2010-01-01

    An important goal of upcoming missions to Mars is to understand if life could have developed there. The task of the Sample Analysis at Mars (SAM) suite of instruments [1] and the other Curiosity investigations [2] is to move us steadily toward that goal with an assessment of the habitability of our neighboring planet through a series of chemical and geological measurements. SAM is designed to search for organic compounds and inorganic volatiles and measure isotope ratios. Other instruments on Curiosity will provide elemental analysis and identify minerals. SAM will analyze both atmospheric samples and gases evolved from powdered rocks that may have formed billions of years ago with Curiosity providing access to interesting sites scouted by orbiting cameras and spectrometers.

  14. Detection of Organics at Mars: How Wet Chemistry Onboard SAM Helps

    NASA Technical Reports Server (NTRS)

    Buch, A.; Freissinet, Caroline; Szopa, C.; Glavin, D.; Coll, P.; Cabane, M.; Eigenbrode, J.; Navarro-Gonzalez, R.; Coscia, D.; Teinturier, S.; Mahaffy, P.

    2013-01-01

    For the first time in the history of space exploration, a mission of interest to astrobiology could be able to analyze refractory organic compounds in the soil of Mars. Wet chemistry experiment allow organic components to be altered in such a way that improves there detection either by releasing the compounds from sample matricies or by changing the chemical structure to be amenable to analytical conditions. The latter is particular important when polar compounds are present. Sample Analysis at Mars (SAM), on the Curiosity rover of the Mars Science Laboratory mission, has onboard two wet chemistry experiments: derivatization and thermochemolysis. Here we report on the nature of the MTBSTFA derivatization experiment on SAM, the detection of MTBSTFA in initial SAM results, and the implications of this detection.

  15. Data handling with SAM and art at the NOνA experiment

    NASA Astrophysics Data System (ADS)

    Aurisano, A.; Backhouse, C.; Davies, G. S.; Illingworth, R.; Mayer, N.; Mengel, M.; Norman, A.; Rocco, D.; Zirnstein, J.

    2015-12-01

    During operations, NOvA produces between 5,000 and 7,000 raw files per day with peaks in excess of 12,000. These files must be processed in several stages to produce fully calibrated and reconstructed analysis files. In addition, many simulated neutrino interactions must be produced and processed through the same stages as data. To accommodate the large volume of data and Monte Carlo, production must be possible both on the Fermilab grid and on off-site farms, such as the ones accessible through the Open Science Grid. To handle the challenge of cataloging these files and to facilitate their off-line processing, we have adopted the SAM system developed at Fermilab. SAM indexes files according to metadata, keeps track of each file's physical locations, provides dataset management facilities, and facilitates data transfer to off-site grids. To integrate SAM with Fermilab's art software framework and the NOvA production workflow, we have developed methods to embed metadata into our configuration files, art files, and standalone ROOT files. A module in the art framework propagates the embedded information from configuration files into art files, and from input art files to output art files, allowing us to maintain a complete processing history within our files. Embedding metadata in configuration files also allows configuration files indexed in SAM to be used as inputs to Monte Carlo production jobs. Further, SAM keeps track of the input files used to create each output file. Parentage information enables the construction of self-draining datasets which have become the primary production paradigm used at NOvA. In this paper we will present an overview of SAM at NOvA and how it has transformed the file production framework used by the experiment.

  16. The survey of autobiographical memory (SAM): a novel measure of trait mnemonics in everyday life.

    PubMed

    Palombo, Daniela J; Williams, Lynne J; Abdi, Hervé; Levine, Brian

    2013-06-01

    Compared to the abundance of laboratory-based memory tasks, few measures exist to assess self-reported memory function. This need is particularly important for naturalistic mnemonic capacities, such as autobiographical memory (recall of events and facts from one's past), because it is difficult to reliably assess in the laboratory. Furthermore, naturalistic mnemonic capacities may show stable individual differences that evade the constraints of laboratory testing. The Survey of Autobiographical Memory (SAM) was designed to assess such trait mnemonics, or the dimensional characterization of self-reported mnemonic characteristics. The SAM comprises items assessing self-reported episodic autobiographical, semantic, and spatial memory, as well as future prospection. In a large sample of healthy young adults, the latent dimensional structure of the SAM was characterized with multiple correspondence analysis (MCA). This analysis revealed dimensions corresponding to general mnemonic abilities (i.e., good vs poor memory across subtypes), spatial memory, and future prospection. While episodic and semantic items did not separate in this data-driven analysis, these categories did show expected dissociations in relation to depression history and to laboratory-based measures of recollection. Remote spatial memory as assessed by the SAM showed the expected advantage for males over females. Spatial memory was also related to autobiographical memory performance. Brief versions of the SAM are provided for efficient research applications. Individual differences in memory function are likely related to other health-related factors, including personality, psychopathology, dementia risk, brain structure and function, and genotype. In conjunction with laboratory or performance based assessments, the SAM can provide a useful measure of naturalistic self-report trait mnemonics for probing these relationships.

  17. Searching for Reduced Carbon on the Surface of Mars: The SAM Combustion Experiment

    NASA Technical Reports Server (NTRS)

    Stern, J. C.; Malespin, C. A.; Mahaffy, P. R.; Webster, C. R.; Eigenbrode, J. L.; Archer, P. D., Jr.; Brunner, A. E.; Freissinet, C.; Franz, H. B.; Glavin, D. P.; Graham, H. V.; McAdam, A. C.; Ming, D. W.; Navarro-Gonzalez, R.; Niles, P. B.; Steele, A.; Sutter, B.; Trainer, M. G.

    2014-01-01

    The search for reduced carbon has been a major focus of past and present missions to Mars. Thermal evolved gas analysis was used by the Viking and Phoenix landers and is currently in use by the Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) to characterize volatiles evolved from solid samples, including those associated with reduced organic species. SAM has the additional capability to perform a combustion experiment, in which a sample of Mars regolith is heated in the presence of oxygen and the composition of the evolved gases is measured using quadrupole mass spectrometry (QMS) and tunable laser spectrometry (TLS) [1]. Organics detection on the Martian surface has been complicated by oxidation and destruction during heating by soil oxidants [2], including oxychlorine compounds, and terrestrial organics in the SAM background contributed by one of the SAM wet chemistry reagents MTBSTFA (N-Methyl-N-tertbutyldimethylsilyl- trifluoroacetamide) [3,4]. Thermal Evolved Gas Analysis (TEGA) results from Phoenix show a mid temperature CO2 release between 400 C - 680 C speculated to be carbonate, CO2 adsorbed to grains, or combustion of organics by soil oxidants [5]. Low temperature CO2 evolutions (approx. 200 C - 400 C) were also present at all three sites in Gale Crater where SAM Evolved Gas Analysis (EGA) was performed, and potential sources include combustion of terrestrial organics from SAM, as well as combustion and/or decarboxylation either indigenous martian or exogenous organic carbon [4,6]. By performing an experiment to intentionally combust all reduced materials in the sample, we hope to compare the bulk abundance of CO2 and other oxidized species evolved by combustion to that evolved during an EGA experiment to estimate how much CO2 could be contributed by reduced carbon sources. In addition, C, O, and H isotopic compositions of CO2 and H2O measured by TLS can contribute information regarding the potential sources of these

  18. Results from the Curiosity Rover's SAM Investigation at Gale Crater and links to Habitability of Mars

    NASA Astrophysics Data System (ADS)

    Coll, P. J.; Mahaffy, P. R.; Webster, C. R.; Cabane, M.; Atreya, S. K.; Conrad, P. G.; Navarro-gonzalez, R.; SAM; MSL Science Teams

    2013-05-01

    The Mars Science Laboratory Mission (MSL) has as its goal an exploration of the potential of the ancient Gale Crater to support life. The Sample Analysis at Mars (SAM) instrument suite (3) contributes to this exploration of habitability with (1) a search for organic compounds in rocks and soils, (2) a determination of the composition of inorganic volatiles compounds in the atmosphere or extracted from solid materials, and (3) measurements of the isotopic composition of several of these volatiles. The initial exploration of the region near the landing point has revealed a diverse geology and SAM has made measurements of both atmospheric and solid samples. Additional prime exploration targets are the clay and sulfate layers in the central mound (Mt. Sharp) of Gale crater. SAM is located in the interior of the Curiosity rover. Nine other instruments complete the payload including an XRD/XRF instrument and a variety of imaging, laser induced breakdown spectroscopy, and elemental analysis instrumentation. Several of these instruments serve to locate sampling sites and interrogate candidate materials before solid sample is collected either with a drill or a scoop for delivery to SAM and the XRD/XRF instruments. SAM's instruments are a quadrupole mass spectrometer (QMS), a tunable laser spectrometer (TLS), and a 6-column gas chromatograph (GC) coupled through a solid sample transport system and a gas processing and enrichment system. SAM atmospheric runs include a determination of: new volume mixing ratios for the 5 major isotopic constituents; an upper limit for the volume mixing ratio of methane; C and O isotope ratios in CO2; D/H in water; and the 40Ar/36Ar ratio. Major evolved gases from fines scooped from an eolian drift were H2O, CO2, O2, SO2, and a number of minor species. Chlorine containing compounds in this material were tentatively identified as perchlorates.

  19. Data handling with SAM and art at the NOvA experiment

    DOE PAGES

    Aurisano, A.; Backhouse, C.; Davies, G. S.; ...

    2015-12-23

    During operations, NOvA produces between 5,000 and 7,000 raw files per day with peaks in excess of 12,000. These files must be processed in several stages to produce fully calibrated and reconstructed analysis files. In addition, many simulated neutrino interactions must be produced and processed through the same stages as data. To accommodate the large volume of data and Monte Carlo, production must be possible both on the Fermilab grid and on off-site farms, such as the ones accessible through the Open Science Grid. To handle the challenge of cataloging these files and to facilitate their off-line processing, we havemore » adopted the SAM system developed at Fermilab. SAM indexes files according to metadata, keeps track of each file's physical locations, provides dataset management facilities, and facilitates data transfer to off-site grids. To integrate SAM with Fermilab's art software framework and the NOvA production workflow, we have developed methods to embed metadata into our configuration files, art files, and standalone ROOT files. A module in the art framework propagates the embedded information from configuration files into art files, and from input art files to output art files, allowing us to maintain a complete processing history within our files. Embedding metadata in configuration files also allows configuration files indexed in SAM to be used as inputs to Monte Carlo production jobs. Further, SAM keeps track of the input files used to create each output file. Parentage information enables the construction of self-draining datasets which have become the primary production paradigm used at NOvA. In this study we will present an overview of SAM at NOvA and how it has transformed the file production framework used by the experiment.« less

  20. SAGE II aerosol data validation - Comparative studies of SAGE II and SAM II data sets

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Mccormick, M. P.; Chu, W. P.; Wang, P. H.; Osborn, M. T.

    1989-01-01

    Data from the Stratospheric Aerosol and Gas Experiment (SAGE II) satellite are compared with data from the Stratospheric Aerosol Measurement (SAM II) satellite. Both experiments produce aerosol extinction profiles by measuring the attenuation of solar radiation during each sunrise and sunset observed by the satelltie. The SAGE II obtains profiles at 1.02 microns and three smaller wavelengths, whereas the SAM II measures at only one radiometric channel at 1.0 microns. It is found that the differences between the two sets of data are generally within the error bars associated with each measurement. In addition, the sunrise and sunset data from SAGE II are analyzed.

  1. Mechanistic studies of the radical SAM enzyme spore photoproduct lyase (SPL).

    PubMed

    Li, Lei

    2012-11-01

    Spore photoproduct lyase (SPL) repairs a special thymine dimer 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct or SP at the bacterial early germination phase. SP is the exclusive DNA photo-damage product in bacterial endospores; its generation and swift repair by SPL are responsible for the spores' extremely high UV resistance. The early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair the SP in the absence of light. The research in the past decade further established SPL as a radical SAM enzyme, which utilizes a tri-cysteine CXXXCXXC motif to harbor a [4Fe-4S] cluster. At the 1+ oxidation state, the cluster provides an electron to the S-adenosylmethionine (SAM), which binds to the cluster in a bidentate manner as the fourth and fifth ligands, to reductively cleave the CS bond associated with the sulfonium ion in SAM, generating a reactive 5'-deoxyadenosyl (5'-dA) radical. This 5'-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. SAM is suggested to be regenerated at the end of each catalytic cycle; and only a catalytic amount of SAM is needed in the SPL reaction. The H atom source for the back donation step is suggested to be a cysteine residue (C141 in Bacillus subtilis SPL), and the H-atom transfer reaction leaves a thiyl radical behind on the protein. This thiyl radical thus must participate in the SAM regeneration process; however how the thiyl radical abstracts an H atom from the 5'-dA to regenerate SAM is unknown. This paper reviews and discusses the history and the latest progress in the mechanistic elucidation of SPL. Despite some recent breakthroughs, more questions are raised in the mechanistic understanding of this intriguing DNA repair enzyme. This article is part of a Special Issue

  2. The Combustion Experiment on the Sample Analysis at Mars (SAM) Instrument Suite on the Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Stern, J. C.; Malespin, C. A.; Eigenbrode, J.; Graham, H. V.; Archer, P. D.; Brunner, A.; Freissinet, C.; Franz, H. B.; Fuentes, J.; Glavin, D. P.; Mahaffy, P. R.; McAdam, A. C.; Ming, D. W.; Niles, P. B.; Steele, A.

    2014-01-01

    The combustion experiment on the Sample Analysis at Mars (SAM) suite on Curiosity will heat a sample of Mars regolith in the presence of oxygen and measure composition of the evolved gases using quadrupole mass spectrometry (QMS) and tunable laser spectrometry (TLS). QMS will enable detection of combustion products such as CO, CO2, NO, and other oxidized species, while TLS will enable precision measurements of the abundance and carbon isotopic composition (delta C-13) of the evolved CO2 and hydrogen isotopic composition (delta D) of H2O. SAM will perform a two-step combustion to isolate combustible materials below approx. 550 C and above approx. 550 C.

  3. The nucleation and growth of calcium oxalate monohydrate on self- assembled monolayers (SAMs)

    SciTech Connect

    Campbell, A.A.; Tarasevich, B.J.; Graff, G.L.; Fryxell, G.E.; Rieke, P.C.

    1992-05-01

    A physical chemical approach was used to study calcium oxalate monohydrate (COM) nucleation and growth on various organic interfaces. Self-assembling monolayers (SAMs), containing derivatized organic functional groups, were designed to mimic various amino acid residues present in both urine and stone matrix macromolecules. Derivatized surfaces include SAMs with terminal methyl, bromo, imidazole, and thiazolidine-carboxylic acid functional groups. Pronounced differences in COM deposition were observed for the various interfaces with the imidazole and thiazolidine surfaces having the greatest effect and the methyl and bromo groups having little or no nucleating potential.

  4. Mineral classification map using MF and SAM techniques: A case study in the Nohwa Island, Korea

    SciTech Connect

    Son, Young-Sun; Yoon, Wang-Jung

    2015-03-10

    The purpose of this study is to map pyprophyllite distribution at surface of the Nohwa deposit, Korea by using Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) data. For this, combined Spectral Angle Mapper (SAM), and Matched Filtering (MF) technique based on mathematical algorithm was applied. The regional distribution of high-grade and low-grade pyrophyllite in the Nohwa deposit area could be differentiated by this method. The results of this study show that ASTER data analysis using combination of SAM and MF techniques will assist in exploration of pyrophyllite at the exposed surface.

  5. Basis for ligand discrimination between ON and OFF state riboswitch conformations: the case of the SAM-I riboswitch.

    PubMed

    Boyapati, Vamsi Krishna; Huang, Wei; Spedale, Jessica; Aboul-Ela, Fareed

    2012-06-01

    Riboswitches are RNA elements that bind to effector ligands and control gene expression. Most consist of two domains. S-Adenosyl Methionine (SAM) binds the aptamer domain of the SAM-I riboswitch and induces conformational changes in the expression domain to form an intrinsic terminator (transcription OFF state). Without SAM the riboswitch forms the transcription ON state, allowing read-through transcription. The mechanistic link between the SAM/aptamer recognition event and subsequent secondary structure rearrangement by the riboswitch is unclear. We probed for those structural features of the Bacillus subtilis yitJ SAM-I riboswitch responsible for discrimination between the ON and OFF states by SAM. We designed SAM-I riboswitch RNA segments forming "hybrid" structures of the ON and OFF states. The choice of segment constrains the formation of a partial P1 helix, characteristic of the OFF state, together with a partial antiterminator (AT) helix, characteristic of the ON state. For most choices of P1 vs. AT helix lengths, SAM binds with micromolar affinity according to equilibrium dialysis. Mutational analysis and in-line probing confirm that the mode of SAM binding by hybrid structures is similar to that of the aptamer. Altogether, binding measurements and in-line probing are consistent with the hypothesis that when SAM is present, stacking interactions with the AT helix stabilize a partially formed P1 helix in the hybrids. Molecular modeling indicates that continuous stacking between the P1 and the AT helices is plausible with SAM bound. Our findings raise the possibility that conformational intermediates may play a role in ligand-induced aptamer folding.

  6. Analysis of the interactions between host factor Sam68 and viral elements during foot-and-mouth disease virus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The nuclear protein Src-associated protein of 68 kDa in mitosis (Sam68) is known to bind RNA and be involved in cellular processes triggered in response to environmental stresses, including virus infection. Interestingly, Sam68, is a multi-functional protein implicated in the life cycle of retroviru...

  7. Targeting EphA2-Sam and Its Interactome: Design and Evaluation of Helical Peptides Enriched in Charged Residues.

    PubMed

    Mercurio, Flavia A; Marasco, Daniela; Di Natale, Concetta; Pirone, Luciano; Costantini, Susan; Pedone, Emilia M; Leone, Marilisa

    2016-11-17

    The EphA2 receptor controls diverse physiological and pathological conditions and its levels are often upregulated in cancer. Targeting receptor overexpression, through modulation of endocytosis and consequent degradation, appears to be an appealing strategy for attacking tumor malignancy. In this scenario, the Sam domain of EphA2 plays a pivotal role because it is the site where protein regulators of endocytosis and stability are recruited by means of heterotypic Sam-Sam interactions. Because EphA2-Sam heterotypic complexes are largely based on electrostatic contacts, we have investigated the possibility of attacking these interactions with helical peptides enriched in charged residues. Several peptide sequences with high predicted helical propensities were designed, and detailed conformational analyses were conducted by diverse techniques including NMR, CD, and molecular dynamics (MD) simulations. Interaction studies were also performed by NMR, surface plasmon resonance (SPR), and microscale thermophoresis (MST) and led to the identification of two peptides capable of binding to the first Sam domain of Odin. These molecules represent early candidates for the generation of efficient Sam domain binders and antagonists of Sam-Sam interactions involving EphA2.

  8. Characterisation of Desulfovibrio vulgaris haem b synthase, a radical SAM family member.

    PubMed

    Lobo, Susana A L; Lawrence, Andrew D; Romão, Célia V; Warren, Martin J; Teixeira, Miguel; Saraiva, Lígia M

    2014-07-01

    An alternative route for haem b biosynthesis is operative in sulfate-reducing bacteria of the Desulfovibrio genus and in methanogenic Archaea. This pathway diverges from the canonical one at the level of uroporphyrinogen III and progresses via a distinct branch, where sirohaem acts as an intermediate precursor being converted into haem b by a set of novel enzymes, named the alternative haem biosynthetic proteins (Ahb). In this work, we report the biochemical characterisation of the Desulfovibrio vulgaris AhbD enzyme that catalyses the last step of the pathway. Mass spectrometry analysis showed that AhbD promotes the cleavage of S-adenosylmethionine (SAM) and converts iron-coproporphyrin III via two oxidative decarboxylations to yield haem b, methionine and the 5'-deoxyadenosyl radical. Electron paramagnetic resonance spectroscopy studies demonstrated that AhbD contains two [4Fe-4S](2+/1+) centres and that binding of the substrates S-adenosylmethionine and iron-coproporphyrin III induces conformational modifications in both centres. Amino acid sequence comparisons indicated that D. vulgaris AhbD belongs to the radical SAM protein superfamily, with a GGE-like motif and two cysteine-rich sequences typical for ligation of SAM molecules and iron-sulfur clusters, respectively. A structural model of D. vulgaris AhbD with putative binding pockets for the iron-sulfur centres and the substrates SAM and iron-coproporphyrin III is discussed.

  9. The transcription factor FBI-1 inhibits SAM68-mediated BCL-X alternative splicing and apoptosis.

    PubMed

    Bielli, Pamela; Busà, Roberta; Di Stasi, Savino M; Munoz, Manuel J; Botti, Flavia; Kornblihtt, Alberto R; Sette, Claudio

    2014-04-01

    Alternative splicing (AS) is tightly coupled to transcription for the majority of human genes. However, how these two processes are linked is not well understood. Here, we unveil a direct role for the transcription factor FBI-1 in the regulation of AS. FBI-1 interacts with the splicing factor SAM68 and reduces its binding to BCL-X mRNA. This, in turn, results in the selection of the proximal 5' splice site in BCL-X exon 2, thereby favoring the anti-apoptotic BCL-XL variant and counteracting SAM68-mediated apoptosis. Conversely, depletion of FBI-1, or expression of a SAM68 mutant lacking the FBI-1 binding region, restores the ability of SAM68 to induce BCL-XS splicing and apoptosis. FBI-1's role in splicing requires the activity of histone deacetylases, whose pharmacological inhibition recapitulates the effects of FBI-1 knockdown. Our study reveals an unexpected function for FBI-1 in splicing modulation with a direct impact on cell survival.

  10. 16. (4'X5' image enlarged from 2 1/4' negative) Sam Fowler, ...

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

    16. (4'X5' image enlarged from 2 1/4' negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE). DETAIL OF TURN-SPAN MECHANISM. - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  11. 15. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, ...

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

    15. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE) PIVOT PIER - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  12. 13. (4'X5' image enlarged from 2 1/4' negative) Sam Fowler, ...

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

    13. (4'X5' image enlarged from 2 1/4' negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE) NORTH SIDE ELEVATION. - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  13. 17. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, ...

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

    17. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE) APPROACH SPAN FENDER - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  14. 12. (4'X5' image enlarged from 2 1/4' negative) Sam Fowler, ...

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

    12. (4'X5' image enlarged from 2 1/4' negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE) SOUTH SIDE ELEVATION. - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  15. 14. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, ...

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

    14. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE) TURN-SPAN AND LOCKING MECHANISM - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  16. The formation of ACC and competition between polyamines and ethylene for SAM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethylene biosynthesis involves the conversion of S-adenosylmethionine (SAM) to 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC synthase (ACS). ACC is then converted to ethylene. The genes that encode enzymes in this pathway all belong to a family of genes. Differential transcriptional regulation ...

  17. Initial SAM calibration gas experiments on Mars: Quadrupole mass spectrometer results and implications

    NASA Astrophysics Data System (ADS)

    Franz, Heather B.; Trainer, Melissa G.; Malespin, Charles A.; Mahaffy, Paul R.; Atreya, Sushil K.; Becker, Richard H.; Benna, Mehdi; Conrad, Pamela G.; Eigenbrode, Jennifer L.; Freissinet, Caroline; Manning, Heidi L. K.; Prats, Benito D.; Raaen, Eric; Wong, Michael H.

    2017-04-01

    The Sample Analysis at Mars (SAM) instrument suite of the Mars Science Laboratory (MSL) Curiosity rover is equipped to analyze both martian atmospheric gases and volatiles released by pyrolysis of solid surface materials, with target measurements including chemical and isotopic composition (Mahaffy et al., 2012). To facilitate assessment of instrument performance and validation of results obtained on Mars, SAM houses a calibration cell containing CO2, Ar, N2, Xe, and several fluorinated hydrocarbon compounds (Franz et al., 2014; Mahaffy et al., 2012). This report describes the first two experiments utilizing this calibration cell on Mars and gives results from analysis of data acquired with the SAM Quadrupole Mass Spectrometer (QMS). These data support the accuracy of isotope ratios obtained with the QMS (Conrad et al., 2016; Mahaffy et al., 2013) and provide ground-truth for reassessment of analytical constants required for atmospheric measurements, which were reported in previous contributions (Franz et al., 2015, 2014). The most significant implication of the QMS data involves reinterpretation of pre-launch contamination previously believed to affect only CO abundance measurements (Franz et al., 2015) to affect N2 abundances, as well. The corresponding adjustment to the N2 calibration constant presented here brings the atmospheric volume mixing ratios for Ar and N2 retrieved by SAM into closer agreement with those reported by the Viking mission (Owen et al., 1977; Oyama and Berdahl, 1977).

  18. Case Studies Comparing System Advisor Model (SAM) Results to Real Performance Data: Preprint

    SciTech Connect

    Blair, N.; Dobos, A.; Sather, N.

    2012-06-01

    NREL has completed a series of detailed case studies comparing the simulations of the System Advisor Model (SAM) and measured performance data or published performance expectations. These case studies compare PV measured performance data with simulated performance data using appropriate weather data. The measured data sets were primarily taken from NREL onsite PV systems and weather monitoring stations.

  19. Construct Validation of the Louisiana School Analysis Model (SAM) Instructional Staff Questionnaire

    ERIC Educational Resources Information Center

    Bray-Clark, Nikki; Bates, Reid

    2005-01-01

    The purpose of this study was to validate the Louisiana SAM Instructional Staff Questionnaire, a key component of the Louisiana School Analysis Model. The model was designed as a comprehensive evaluation tool for schools. Principle axis factoring with oblique rotation was used to uncover the underlying structure of the SISQ. (Contains 1 table.)

  20. Statement of Facts for 1977 City-Wide Mock Trial Competitions. Walker Thomas v. Sam Nomad.

    ERIC Educational Resources Information Center

    National Inst. for Citizen Education in the Law, Washington, DC.

    Prepared by the District of Columbia Street Law Project for its annual city-wide mock trial competition, this instructional handout provides material for a civil case over an automobile accident. Walker Thomas is suing Sam Nomad for damages that resulted from a collision, for which both parties blame the other. The handout clarifies the laws and…

  1. 77 FR 187 - Federal Acquisition Regulation; Transition to the System for Award Management (SAM)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-03

    ...: Deletes the definition at 2.101 for ``business partner network,'' which is no longer necessary in the SAM architecture. Deletes reference to ``business partner network'' at 4.1100, Scope, which is no longer necessary....101, in paragraph (b)(2) by removing the definition ``Business Partner Network (BPN)'' and...

  2. Halomethane production in plants: Structure of the biosynthetic SAM-dependent halide methyltransferase from Arabidopsis thaliana**

    PubMed Central

    Schmidberger, Jason W.; James, Agata B.; Edwards, Robert; Naismith, James H.; O’Hagan, David

    2012-01-01

    A product structure of the halomethane producing enzyme in plants (Arabidopsis thaliana) is reported and a model for presentation of chloride/bromide ion to the methyl group of S-adenosyl-L-methionine (SAM) is presented to rationalise nucleophilic halide attack for halomethane production, gaseous natural products that are produced globally. PMID:20376845

  3. What can we learn from Wet Chemistry onboard the Mars Science Laboratory SAM Suite?

    NASA Astrophysics Data System (ADS)

    Buch, A.; Szopa, C.; Coll, P.; Eigenbrode, J.; Coscia, D.; Navarro Gonzalez, R.; Cabane, M.; MSL Science Team

    2013-09-01

    Direct pyrolysis of Mars soil samples has been used up today today to analyse their content in volatile molecules. However, this technique has been shown to have limitation for the analysis of a few chemical families, or macromolecules. The SAM experiment is the first space instrument onboarding a device based on wet chemistry to overcome this limitation.

  4. Treating Obsessive-Compulsive Disorder and Schizophrenia: The Case of Sam

    ERIC Educational Resources Information Center

    Peasley-Miklus, Catherine; Massie, Elise; Baslett, Gaston; Carmin, Cheryl

    2005-01-01

    This article describes the case of Sam, a 22-year-old male with obsessive-compulsive disorder (OCD) and schizophrenia. The patient's background, the development and characteristics of his OCD and schizophrenia, and the history of what became a rather complicated treatment are described. In addition, four problem areas of therapy are identified.

  5. Molten Salt Power Tower Cost Model for the System Advisor Model (SAM)

    SciTech Connect

    Turchi, C. S.; Heath, G. A.

    2013-02-01

    This report describes a component-based cost model developed for molten-salt power tower solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), using data from several prior studies, including a contracted analysis from WorleyParsons Group, which is included herein as an Appendix. The WorleyParsons' analysis also estimated material composition and mass for the plant to facilitate a life cycle analysis of the molten salt power tower technology. Details of the life cycle assessment have been published elsewhere. The cost model provides a reference plant that interfaces with NREL's System Advisor Model or SAM. The reference plant assumes a nominal 100-MWe (net) power tower running with a nitrate salt heat transfer fluid (HTF). Thermal energy storage is provided by direct storage of the HTF in a two-tank system. The design assumes dry-cooling. The model includes a spreadsheet that interfaces with SAM via the Excel Exchange option in SAM. The spreadsheet allows users to estimate the costs of different-size plants and to take into account changes in commodity prices. This report and the accompanying Excel spreadsheet can be downloaded at https://sam.nrel.gov/cost.

  6. 19. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, ...

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

    19. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE). NAVIGATIONAL LIGHT LOCATED ON TOP OF FENDER - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  7. Local sphere-based co-registration for SAM group analysis in subjects without individual MRI.

    PubMed

    Steinstraeter, O; Teismann, Inga K; Wollbrink, A; Suntrup, S; Stoeckigt, K; Dziewas, R; Pantev, C

    2009-03-01

    Synthetic aperture magnetometry (SAM) is a powerful MEG source localization method to analyze evoked as well as induced brain activity. To gain structural information of the underlying sources, especially in group studies, individual magnetic resonance images (MRI) are required for co-registration. During the last few years, the relevance of MEG measurements on understanding the pathophysiology of different diseases has noticeable increased. Unfortunately, especially in patients and small children, structural MRI scans cannot always be performed. Therefore, we developed a new method for group analysis of SAM results without requiring structural MRI data that derives its geometrical information from the individual volume conductor model constructed for the SAM analysis. The normalization procedure is fast, easy to implement and integrates seamlessly into an existing landmark based MEG-MRI co-registration procedure. This new method was evaluated on different simulated points as well as on a pneumatic index finger stimulation paradigm analyzed with SAM. Compared with an established MRI-based normalization procedure (SPM2) the new method shows only minor errors in single subject results as well as in group analysis. The mean difference between the two methods was about 4 mm for the simulated as well as for finger stimulation data. The variation between individual subjects was generally higher than the error induced by the missing MRIs. The method presented here is therefore sufficient for most MEG group studies. It allows accomplishing MEG studies with subject groups where MRI measurements cannot be performed.

  8. Constraints on the Mineralogy of Gale Crater Mudstones from MSL SAM Evolved Water

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Sutter, B.; Franz, H. B.; Hogancamp, J. V. (Clark); Knudson, C. A.; Andrejkovicova, S.; Archer, P. D.; Eigenbrode, J. L.; Ming, D. W.; Mahaffy, P. R.

    2017-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) have analysed more than 150 micron fines from 14 sites at Gale Crater. Here we focus on the mudstone samples. Two were drilled from sites John Klein (JK) and Cumberland (CB) in the Sheepbed mudstone. Six were drilled from Murray Formation mudstone: Confidence Hills (CH), Mojave (MJ), Telegraph Peak (TP), Buckskin (BK), Oudam (OU), Marimba (MB). SAM's evolved gas analysis mass spectrometry (EGA-MS) detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases, including organic fragments. The identity and evolution temperature of evolved gases can support CheMin mineral detection and place constraints on trace volatile-bearing phases or phases difficult to characterize with X-ray diffraction (e.g., amorphous phases). Here we will focus on SAM H2O data and comparisons to SAM-like analyses of key reference materials.

  9. Mercury astronaut John Glenn at the Sam Houston Colosseum, Houston, Texas

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Mercury astronaut John H. Glenn Jr., wearing a new cowboy hat and a badge in the shape of a star, leafs through his program as he is served his food at the Sam Houston Colosseum. A large crowd was on hand to welcome them to Houston, Texas.

  10. Mechanism elucidation of the radical SAM enzyme spore photoproduct lyase (SPL)

    PubMed Central

    Li, Lei

    2011-01-01

    Spore photoproduct lyase (SPL) repairs a special thymine dimer 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct or SP at the bacterial early germination phase. SP is the exclusive DNA photo-damage product in bacterial endospores; its generation and swift repair by SPL are responsible for the spores’ extremely high UV resistance. The early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair the SP in the absence of light. The research in the past decade further established SPL as a radical SAM enzyme, which utilizes a tri-cysteine CXXXCXXC motif to harbor a [4Fe-4S] cluster. At the 1+ oxidation state, the cluster provides an electron to the S-adenosylmethionine (SAM), which binds to the cluster in a bidentate manner as the fourth and fifth ligands, to reductively cleave the C-S bond associated with the sulfonium ion in SAM, generating a reactive 5′-deoxyadenosyl (5′-dA) radical. This 5′-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. SAM is suggested to be regenerated at the end of each catalytic cycle; and only a catalytic amount of SAM is needed in the SPL reaction. The H atom source for the back donation step is suggested to be a cysteine residue (C141 in B. subtilis SPL), and the H-atom transfer reaction leaves a thiyl radical behind on the protein. This thiyl radical thus must participate in the SAM regeneration process; however how the thiyl radical abstracts an H atom from the 5′-dA to regenerate SAM is unknown. This paper reviews and discusses the history and the latest progress in the mechanistic elucidation of SPL. Despite some recent breakthroughs, more questions are raised in the mechanistic understanding of this intriguing DNA repair enzyme. PMID:22197590

  11. Determination of the Possible Source of Chlorinated Hydrocarbons Detected By SAM during MSL Mission

    NASA Astrophysics Data System (ADS)

    Buch, A.; Belmahdi, I.; Szopa, C.; Freissinet, C.; Glavin, D. P.; Francois, P.; Coll, P. J.; Miller, K.; Eigenbrode, J. L.; Stern, J. C.; Navarro-Gonzalez, R.; McAdam, A.; Teinturier, S.; Bonnet, J. Y.; Summons, R. E.; Millan, M.; Dequaire, T.; Cabane, M.; Mahaffy, P. R.

    2014-12-01

    The SAM GC-MS instrument on the Curiosity rover allows to analyze volatile compounds from the atmosphere or volatile compounds from the Martian regolith and refractory compounds in the regolith after sample treatment using wet chemistry. One portion of the wet chemistry experiment is composed of MTBSTFA (N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide) / DMF (dimethylformamide). Abundant chlorinated hydrocarbons have been detected with SAM when analyzing samples collected in several sites explored by Curiosity rover. Some of these chlorohydrocarbons are produced during pyrolysis by the reaction of Martian oxychlorine compounds in the samples with terrestrial carbon from a derivatization agent (MTBSTFA) used in SAM (1, 2). Chlorobenzene cannot be formed by the direct reaction of MTBSTFA and DMF when heated in the presence of fused silica and perchlorates under SAM-like conditions (1)) therefore two other reaction pathways for chlorobenzene were proposed : (1) reactions between the volatile thermal degradation products of perchlorates (e.g. O2, Cl2 and HCl) and Tenax® and (2) the interaction of perchlorates with organic material from the martian regolith such as benzenecarboxylates (3, 4). This study investigates several propositions for chlorinated hydrocarbon formation by looking for: (1) all products coming from the interaction of Tenax® (which is part of the SAM hydrocarbon trap) and perchlorates, (2) also between some soil sample and perchlorates in the presence or absence of MTBSTFA and (c) sources of chlorinated hydrocarbon precursors. References: 1. D. P. Glavin et al.(2013) JGR 118, 1955-1973. 2. L. a Leshin et al. (2013) Science 341, 1238937. 3. C. Freissinet et al. (2014) LPSC XXXXV Abstract 2796. 4. D. Glavin et al. (2014) LPSC XXXV Abstract #1157.

  12. Molecular cloning, characterization and expression analysis of the SAMS gene during adventitious root development in IBA-induced tetraploid black locust.

    PubMed

    Quan, Jine; Zhang, Sheng; Zhang, Chunxia; Meng, Sen; Zhao, Zhong; Xu, Xuexuan

    2014-01-01

    S-Adenosylmethionine synthetase (SAMS) catalyzes the synthesis of S-adenosylmethionine (SAM), a precursor for ethylene and polyamine biosynthesis. Here, we report the isolation of the 1498 bp full-length cDNA sequence encoding tetraploid black locust (Robinia pseudoacacia L.) SAMS (TrbSAMS), which contains an open reading frame of 1179 bp encoding 392 amino acids. The amino acid sequence of TrbSAMS has more than 94% sequence identity to SAMSs from other plants, with a closer phylogenetic relationship to SAMSs from legumes than to SAMS from other plants. The TrbSAMS monomer consists of N-terminal, central, and C-terminal domains. Subcellular localization analysis revealed that the TrbSAMS protein localizes mainly to in the cell membrane and cytoplasm of onion epidermal cells and Arabidopsis mesophyll cell protoplasts. Indole-3-butyric acid (IBA)-treated cuttings showed higher levels of TrbSAMS transcript than untreated control cuttings during root primordium and adventitious root formation. TrbSAMS and its downstream genes showed differential expression in shoots, leaves, bark, and roots, with the highest expression observed in bark. IBA-treated cuttings also showed higher SAMS activity than control cuttings during root primordium and adventitious root formation. These results indicate that TrbSAMS might play an important role in the regulation of IBA-induced adventitious root development in tetraploid black locust cuttings.

  13. Hydroxyapatite coatings.

    PubMed

    Lacefield, W R

    1988-01-01

    Four coating techniques were evaluated to determine which is most suitable for producing a dense, highly adherent coating onto metallic and ceramic implant materials. Two of the selected coating methods have serious limitations for use in this particular application, and did not meet the specified criteria for satisfactory coating as defined in the initial stages of the study. For example, the dip coating-sintering technique was judged to be unsatisfactory because of the adverse effect of the high-temperature sintering cycle on the mechanical properties of the metallic substrate materials. These materials could not be used in load-bearing applications because of the excessive grain growth and loss of the wrought structure of both the commercially pure Ti and Ti-6Al-4V substrates, and the loss of ductility in the cast Co-Cr-Mo alloy. Another area of concern was that bond strength between the HA coating and the substrate was not high enough to insure that interfacial failure would not occur during the lifetime of the implant. The immersion-coating technique, in which the metal substrate is immersed into the molten ceramic, was shown in a previous study to be the best method of coating a bioreactive glass onto a Co-Cr-Mo implant. Heating HA above its melting temperature, however, caused undesired compositional and structural changes, and upon solidification very limited adherence between the modified ceramic and substrate material occurred under the conditions of this study. The HIP technique, in which the Ti powder substrate and the HA powder coating are sintered together in a high-pressure autoclave, shows great promise for the fabrication of high-quality composite implants. Initial studies have indicated that high-density Ti substrates with a small grain size that are well bonded to a dense HA coating can be produced under optimum conditions. Sintering and densification additives, such as SiO2 powder, do not appear to be necessary. The main drawback to this

  14. Analogue Experiments Identify Possible Precursor Compounds for Chlorohydrocarbons Detected in SAM

    NASA Astrophysics Data System (ADS)

    Miller, K.; Summons, R. E.; Eigenbrode, J. L.; Freissinet, C.; Glavin, D. P.; Martin, M. G.; Team, M.

    2013-12-01

    Since landing at Gale Crater on August 6, 2012, the Sample Analysis at Mars (SAM) instrument suite, aboard the Curiosity Rover, has conducted multiple analyses of scooped and drilled samples and has identified a suite of chlorohydrocarbons including chloromethane, dichloromethane, trichloromethane, chloromethylpropene, and chlorobenzene (Glavin et al., 2013; Leshin et al., 2013). These compounds were identified after samples were pyrolysed at temperatures up to ~835°C through a combination of Evolved Gas Analysis (EGA) and Gas Chromatography Mass Spectrometry (GCMS). Since these chlorinated species were well above the background levels determined by empty cup blanks analyzed prior to solid sample analyses, thermal degradation of oxychlorine phases, such as perchlorate, present in the Martian soil, are the most likely source of chlorine needed to generate these chlorohydrocarbons. Laboratory analogue experiments show that terrestrial organics internal to SAM, such as N-methyl-N(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), a derivatization agent, can react with perchlorates to produce all of the chlorohydrocarbons detected by SAM. However, in pyrolysis-trap-GCMS laboratory experiments with MTBSTFA, C4 compounds are the predominant chlorohydrocarbon observed, whereas on SAM the C1 chlorohydrocarbons dominate (Glavin et al., 2013). This, in addition to the previous identification of chloromethane and dichloromethane by the 1976 Viking missions (Biemann et al., 1977), suggest that there could be another, possibly Martian, source of organic carbon contributing to the formation of the C1 chlorohydrocarbons, or other components of the solid samples analyzed by SAM are having a catalytic effect on chlorohydrocarbon generation. Laboratory analogue experiments investigated a suite of organic compounds that have the potential to accumulate on Mars (Benner et al., 2000) and thus serve as sources of carbon for the formation of chlorohydrocarbons detected by the SAM and

  15. Sam68/KHDRBS1 is critical for colon tumorigenesis by regulating genotoxic stress-induced NF-κB activation

    PubMed Central

    Fu, Kai; Sun, Xin; Wier, Eric M; Hodgson, Andrea; Liu, Yue; Sears, Cynthia L; Wan, Fengyi

    2016-01-01

    Nuclear factor kappa B (NF-κB)-mediated transcription is an important mediator for cellular responses to DNA damage. Genotoxic agents trigger a 'nuclear-to-cytoplasmic' NF-κB activation signaling pathway; however, the early nuclear signaling cascade linking DNA damage and NF-κB activation is poorly understood. Here we report that Src-associated-substrate-during-mitosis-of-68kDa/KH domain containing, RNA binding, signal transduction associated 1 (Sam68/KHDRBS1) is a key NF-κB regulator in genotoxic stress-initiated signaling pathway. Sam68 deficiency abolishes DNA damage-stimulated polymers of ADP-ribose (PAR) production and the PAR-dependent NF-κB transactivation of anti-apoptotic genes. Sam68 deleted cells are hypersensitive to genotoxicity caused by DNA damaging agents. Upregulated Sam68 coincides with elevated PAR production and NF-κB-mediated anti-apoptotic transcription in human and mouse colon cancer. Knockdown of Sam68 sensitizes human colon cancer cells to genotoxic stress-induced apoptosis and genetic deletion of Sam68 dampens colon tumor burden in mice. Together our data reveal a novel function of Sam68 in the genotoxic stress-initiated nuclear signaling, which is crucial for colon tumorigenesis. DOI: http://dx.doi.org/10.7554/eLife.15018.001 PMID:27458801

  16. Antarctic SAM-temperature relationships in the historical CMIP5 model runs

    NASA Astrophysics Data System (ADS)

    Marshall, G.; Bracegirdle, T.

    2013-12-01

    Variability in the Southern Annular Mode (SAM) is associated with a distinct spatial pattern of near-surface temperature anomalies across the Antarctic continent: a more positive SAM is generally linked with warming over the Antarctic Peninsula and cooler temperatures over East Antarctica. However, recent studies have shown that on decadal timescales these SAM-temperature relationships (STRs) can break down and even reverse in sign. Due to the relatively short (~50 years) timescale of available observations it is difficult to determine whether such reversals have occurred in response to anthropogenic forcing or are simply part of natural internal climate variability. Future Antarctic temperature change over the 21st Century is likely to be highly dependent on how the SAM responds to a combination of ozone recovery and greenhouse gas increases, which modelling studies suggest will have opposing effects on the sign of the SAM. Decadal variability in Antarctic STRs will be a major contributing factor to the uncertainty attached to such predictions. Therefore, as a first step in refining such predictions, we examine how well the Coupled Model Intercomparison Phase 5 (CMIP5) models, which provide climate projections for the latest IPCC assessment report, capture STR decadal variability across Antarctica. We analyze the seasonal STR at six Antarctic stations in the historical CMIP5 model runs, which typically encompass the period from 1850-2005. The stations were chosen because they have different seasonal patterns of STR; e.g. consistent across all seasons, one season where the STR is much stronger, or a change in the STR sign across the year. We utilize data from 50 different CMIP5 models comprising 183 separate model runs. First, we examine how well the models determine the long-term seasonal STR correlation and regression coefficients for the 1961-2000 period at each station, as compared to equivalent observations. Second, we investigate whether the models capture

  17. Early Results from the Curiosity Rover's SAM Investigation at Gale Crater

    NASA Astrophysics Data System (ADS)

    Mahaffy, Paul; Webster, Chris; Cabane, Michael; Coll, Patrice

    2013-04-01

    The goals of the Mars Science Laboratory Mission (1, 2) are to explore the potential of the Gale Crater landing site to support life either in the distant past or the present. The contribution of the Sample Analysis at Mars (SAM) instrument suite (3) in this exploration of habitability is (A) to search for organic compounds in rocks and soils, (B) to determine the composition of inorganic volatiles compounds in the atmosphere or extracted from solid materials, and (C) to measure the isotopic composition of several of these volatiles. While prime exploration targets of MSL's Curiosity Rover are the layers in the central mound (Mt. Sharp) of Gale crater the initial exploration of region near the landing point has revealed a diverse geology and the early part of the mission has been spent both commissioning the 10 Curiosity instruments and the Rover subsystems and making first time measurements of both atmospheric and solid samples. SAM is located in the interior of MSL's Curiosity rover next to the XRD/XRF CheMin instrument. A variety of imaging, laser induced breakdown spectroscopy, and elemental analysis instrumentation serves to locate sampling sites and interogate candidate materials before solid sample is collected either with a drill or a scoop for delivery to SAM and CheMin. SAM's instruments are a quadrupole mass spectrometer (QMS), a tunable laser spectrometer (TLS), and a 6-column gas chromatograph (GC). These are coupled through a solid sample transport system and a gas processing and enrichment system. The SAM suite is able to measure a suite of light isotopes and to analyze volatiles directly from the atmosphere or thermally released from solid samples. Early results from SAM atmospheric runs include a determination of: new volume mixing ratios for the 5 major isotopic constituents showing Ar approximately equal to N2; an upper limit of 3.5 ppb for the volume mixing ratio of methane; C and O isotope ratios showing both heavier than terrestrial averages

  18. Early Evolved Gas Results from the Curiosity Rover’s SAM Investigation at Gale Crater

    NASA Astrophysics Data System (ADS)

    Mahaffy, Paul R.; Franz, H.; McAdam, A.; Brunner, A.; Eigenbrode, J.; Stern, J.; SAM Science Team; MSL Science Team

    2013-10-01

    The Mars Science Laboratory Mission is designed to explore the habitability of the selected landing site at Gale crater. The Sample Analysis at Mars (SAM) instrument suite contributes to this study with a search for organic compounds, an analysis of the composition of inorganic volatiles, and measurements of the isotopic composition light elements. Both atmospheric and solid samples are analyzed. The layers in the central mound (Mt. Sharp) of Gale crater are important targets for the MSL mission. However, in situ measurements made during the past year of interesting regions close to the Bradbury landing site have revealed a diverse geology and several primary mission objectives have already been realized. SAM is located in the interior of the Curiosity rover. The MSL cameras, a laser induced breakdown spectrometer, and elemental analysis instrumentation serves to locate sampling sites and interogate candidate materials before solid sample is collected either with a drill or a scoop for delivery to SAM and the XRD instrument CheMin. SAM integrates a quadrupole mass spectrometer (QMS), a tunable laser spectrometer (TLS), and a 6-column gas chromatograph (GC) with a solid sample transport system and a gas processing and enrichment system. Results of SAM atmospheric composition analyses have already been reported (1,2). To date, multiple SAM evolved gas experiments have examined samples from fines scooped from an aeolian drift and from two drilled samples of a mudstone. Major evolved gases are H2O, CO2, O2, SO2, H2S, H2, and a number of minor species. These data help confirm the likely presence of perchlorates, the presence of phylosillicates, and both reduced and oxidized compounds evolved from the same sample. 1) P.R. Mahaffy et al., Abundance and Isotopic Composition of Gases in the Martian Atmosphere from the Curiosity Rover, Science 343, (2013). 2) C.R. Webster et al., Isotope Ratios of H, C and O in Martian Atmospheric Carbon Dioxide and Water Measured by the

  19. Successful treatment tailored to each splanchnic arterial lesion due to segmental arterial mediolysis (SAM): report of a case.

    PubMed

    Hashimoto, Takuya; Deguchi, Juno; Endo, Hisako; Miyata, Tetsuro

    2008-11-01

    Segmental arterial mediolysis (SAM) is a rare condition characterized by splanchnic arterial catastrophe caused by mediolysis. We report a 59-year-old man with a ruptured splenic arterial aneurysm who was successfully treated by coil embolization. He underwent additional resection of large gastroepiploic and residual splenic aneurysms. Pathological examination showed mediolysis and tearing, compatible with SAM. Furthermore, he developed acute dissection of the superior mesenteric artery (SMA) one and a half years later, demonstrated by computed tomography. This report demonstrates that SAM is characterized by multiple lesions of the splanchnic arteries at different times, and requires treatment suited to the lesions, including careful long-term observation.

  20. Curiosity's Sample Analysis at Mars (SAM) Investigation: Overview of Results from the First 120 Sols on Mars

    NASA Technical Reports Server (NTRS)

    Mahaffy, P. R.; Cabane, M.; Webster, C. R.; Archer, P. D.; Atreya, S. K.; Benna, M.; Brinckerhoff, W. B.; Brunner, A. E.; Buch, A.; Coll, P.; Conrad, P. G.; Coscia, D.; Dobson, N.; Dworkin, J. P.; Eigenbrode, J. L.; Farley, K. A.; Flesch, G.; Franz, H. B.; Freissinet, C.; Gorevan, S.; Glavin, D. P.; Grotzinger, J. P.; Harpold, D. N.; Hengemihle, J.; Jaeger, F.

    2013-01-01

    During the first 120 sols of Curiosity s landed mission on Mars (8/6/2012 to 12/7/2012) SAM sampled the atmosphere 9 times and an eolian bedform named Rocknest 4 times. The atmospheric experiments utilized SAM s quadrupole mass spectrometer (QMS) and tunable laser spectrometer (TLS) while the solid sample experiments also utilized the gas chromatograph (GC). Although a number of core experiments were pre-programmed and stored in EEProm, a high level SAM scripting language enabled the team to optimize experiments based on prior runs.

  1. Evolved Gas Analyses of Sedimentary Materials in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars (SAM) Instrument from Yellowknife Bay to the Stimson Formation

    NASA Technical Reports Server (NTRS)

    Sutter, B.; McAdam, A. C.; Rampe, E. B.; Ming, D. W.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Stern, J. C.; Eigenbrode, J. L.; Archer, P. D.

    2016-01-01

    The Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory rover has analyzed 10 samples from Gale Crater. All SAM evolved gas analyses have yielded a multitude of volatiles (e.g, H2O, SO2, H2S, CO2, CO, NO, O2, HC1). The objectives of this work are to 1) Characterize the evolved H2O, SO2, CO2, and O2 gas traces of sediments analyzed by SAM through sol 1178, 2) Constrain sediment mineralogy/composition based on SAM evolved gas analysis (SAM-EGA), and 3) Discuss the implications of these results releative to understanding the geochemical history of Gale Crater.

  2. Regulatory Aspects of Coatings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter gives a history of the development and uses of edible coating regulations, detailed chapters on coating caracteristics, determination of coating properties, methods for making coatings, and discription of coating film formers (polysaccharieds, lipids, resins, proteins). The chapter also...

  3. Polar stratospheric cloud sightings by SAM II. [Stratospheric Aerosol Measurement onboard Nimbus 7

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Chu, W. P.; Steele, H. M.; Hamill, P.; Swissler, T. J.

    1982-01-01

    The functions and data gained regarding stratospheric cloud sightings by the stratospheric aerosol measurement (SAM) II experiment on board the Numbus 7 spacecraft are reported. SAM II comprises a single channel sun photometer centered at 1.0 micron wavelength for measuring the solar intensity when the sun descends below an apparent 300 km altitude until the sun is occulted by clouds or the horizon. Readings are also made during sunrise in an opposite fashion. Transmission profiles are developed from the data and used to construct profiles of aerosol extinction with a 1 km resolution. Polar stratospheric clouds have been observed in more than 90% of the cases when the minimum temperature is 185 K or less, and 45% of the time when the temperature is 193 K or less. The clouds were more prevalent in the Antarctic winter than during the Arctic winter, and cloud height was lower than indicated by previous data.

  4. Catch-and-Release of Target Cells Using Aptamer-Conjugated Electroactive Zwitterionic Oligopeptide SAM

    PubMed Central

    Enomoto, Junko; Kageyama, Tatsuto; Osaki, Tatsuya; Bonalumi, Flavia; Marchese, Francesca; Gautieri, Alfonso; Bianchi, Elena; Dubini, Gabriele; Arrigoni, Chiara; Moretti, Matteo; Fukuda, Junji

    2017-01-01

    Nucleic acid aptamers possess attractive features such as specific molecular recognition, high-affinity binding, and rapid acquisition and replication, which could be feasible components for separating specific cells from other cell types. This study demonstrates that aptamers conjugated to an oligopeptide self-assembled monolayer (SAM) can be used to selectively trap human hepatic cancer cells from cell mixtures containing normal human hepatocytes or human fibroblasts. Molecular dynamics calculations have been performed to understand how the configurations of the aptamers are related to the experimental results of selective cell capture. We further demonstrate that the captured hepatic cancer cells can be detached and collected along with electrochemical desorption of the oligopeptide SAM, and by repeating these catch-and-release processes, target cells can be enriched. This combination of capture with aptamers and detachment with electrochemical reactions is a promising tool in various research fields ranging from basic cancer research to tissue engineering applications. PMID:28266533

  5. Sam the Monkey After His Ride in the Little Joe 2 Spacecraft

    NASA Technical Reports Server (NTRS)

    1959-01-01

    Sam, the Rhesus monkey, after his ride in the Little Joe-2 (LJ-2) spacecraft. A U.S. Navy destroyer safely recovered Sam after he experienced three minutes of weightlessness during the flight. Animals were often used during test flights for Project Mercury to help determine the effects of spaceflight and weightlessness on humans. LJ-2 was one in a series of flights that led up to the human orbital flights of NASA's Project Mercury program. The Little Joe rocket booster was developed as a cheaper, smaller, and more functional alternative to the Redstone rockets. Little Joe could be produced at one-fifth the cost of Redstone rockets and still have enough power to carry a capsule payload. Seven unmanned Little Joe rockets were launched from Wallops Island, Virginia from August 1959 to April 1961.

  6. Parabolic Trough Reference Plant for Cost Modeling with the Solar Advisor Model (SAM)

    SciTech Connect

    Turchi, C.

    2010-07-01

    This report describes a component-based cost model developed for parabolic trough solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), assisted by WorleyParsons Group Inc., for use with NREL's Solar Advisor Model (SAM). This report includes an overview and explanation of the model, two summary contract reports from WorleyParsons, and an Excel spreadsheet for use with SAM. The cost study uses a reference plant with a 100-MWe capacity and six hours of thermal energy storage. Wet-cooling and dry-cooling configurations are considered. The spreadsheet includes capital and operating cost by component to allow users to estimate the impact of changes in component costs.

  7. Catch-and-Release of Target Cells Using Aptamer-Conjugated Electroactive Zwitterionic Oligopeptide SAM.

    PubMed

    Enomoto, Junko; Kageyama, Tatsuto; Osaki, Tatsuya; Bonalumi, Flavia; Marchese, Francesca; Gautieri, Alfonso; Bianchi, Elena; Dubini, Gabriele; Arrigoni, Chiara; Moretti, Matteo; Fukuda, Junji

    2017-03-07

    Nucleic acid aptamers possess attractive features such as specific molecular recognition, high-affinity binding, and rapid acquisition and replication, which could be feasible components for separating specific cells from other cell types. This study demonstrates that aptamers conjugated to an oligopeptide self-assembled monolayer (SAM) can be used to selectively trap human hepatic cancer cells from cell mixtures containing normal human hepatocytes or human fibroblasts. Molecular dynamics calculations have been performed to understand how the configurations of the aptamers are related to the experimental results of selective cell capture. We further demonstrate that the captured hepatic cancer cells can be detached and collected along with electrochemical desorption of the oligopeptide SAM, and by repeating these catch-and-release processes, target cells can be enriched. This combination of capture with aptamers and detachment with electrochemical reactions is a promising tool in various research fields ranging from basic cancer research to tissue engineering applications.

  8. Wide Range Vacuum Pumps for the SAM Instrument on the MSL Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Sorensen, Paul; Kline-Schoder, Robert; Farley, Rodger

    2014-01-01

    Creare Incorporated and NASA Goddard Space Flight Center developed and space qualified two wide range pumps (WRPs) that were included in the Sample Analysis at Mars (SAM) instrument. This instrument was subsequently integrated into the Mars Science Laboratory (MSL) "Curiosity Rover," launched aboard an Atlas V rocket in 2011, and landed on August 6, 2012, in the Gale Crater on Mars. The pumps have now operated for more than 18 months in the Gale Crater and have been evacuating the key components of the SAM instrument: a quadrupole mass spectrometer, a tunable laser spectrometer, and six gas chromatograph columns. In this paper, we describe the main design challenges and the ways in which they were solved. This includes the custom design of a miniaturized, high-speed motor to drive the turbo drag pump rotor, analysis of rotor dynamics for super critical operation, and bearing/lubricant design/selection.

  9. Equatorial semiannual oscillation in zonally averaged temperature observed by the Nimbus 7 SAMS and LIMS

    NASA Astrophysics Data System (ADS)

    Delisi, Donald P.; Dunkerton, Timothy J.

    1988-04-01

    Zonally averaged equatorial temperatures obtained aboard Nimbus 7 by the stratospheric and mesospheric sounder (SAMS) are compared to comparable data obtained from the limb IR monitor of the stratosphere. The SAMS data are shown to confirm the seasonal asymmetry in semiannual wind regimes previously noted in rocketsonde observations near the equator. Two explanations for the asymmetry are considered: (1) an improved Kelvin and gravity wave transmissivity in stronger equatorial easterlies (resulting from planetary Rossby wave momentum transport), implying stronger westerly mean flow acceleration in the first cycle than in the second; and (2) evidence of strong polar-tropical coupling in the northern winter indicating that mean meridional circulations are present on a global scale.

  10. 20. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, ...

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

    20. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE). DETAIL OF FENDER SYSTEM FOR TURN-SPAN PIVOT PIER. OPERATOR'S HOUSE LOCATED ON UPPER SECTION OF TRUSS - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  11. SAM II aerosol profile measurements, Poker Flat, Alaska; July 16-19, 1979

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Chu, W. P.; Mcmaster, L. R.; Grams, G. W.; Herman, B. M.; Pepin, T. J.; Russell, P. B.; Swissler, T. J.

    1981-01-01

    SAM II satellite measurements during the July 1979 Poker Flat mission, yielded an aerosol extinction coefficient of 0.0004/km at 1.0 micron wavelength, in the region of the stratospheric aerosol mixing ratio peak (12-16 km). The stratospheric aerosol optical depth for these data, calculated from the tropopause through 30 km, is approximately 0.001. These results are consistent with the average 1979 summertime values found throughout the Arctic.

  12. Sarm1-mediated axon degeneration requires both SAM and TIR interactions.

    PubMed

    Gerdts, Josiah; Summers, Daniel W; Sasaki, Yo; DiAntonio, Aaron; Milbrandt, Jeffrey

    2013-08-14

    Axon degeneration is an evolutionarily conserved pathway that eliminates damaged or unneeded axons. Manipulation of this poorly understood pathway may allow treatment of a wide range of neurological disorders. In an RNAi-based screen performed in cultured mouse DRG neurons, we observed strong suppression of injury-induced axon degeneration upon knockdown of Sarm1 [SARM (sterile α-motif-containing and armadillo-motif containing protein)]. We find that a SARM-dependent degeneration program is engaged by disparate neuronal insults: SARM ablation blocks axon degeneration induced by axotomy or vincristine treatment, while SARM acts in parallel with a soma-derived caspase-dependent pathway following trophic withdrawal. SARM is a multidomain protein that associates with neuronal mitochondria. Deletion of the N-terminal mitochondrial localization sequence disrupts SARM mitochondrial localization in neurons but does not alter its ability to promote axon degeneration. In contrast, mutation of either the SAM (sterile α motif) or TIR (Toll-interleukin-1 receptor) domains abolishes the ability of SARM to promote axonal degeneration, while a SARM mutant containing only these domains elicits axon degeneration and nonapoptotic neuronal death even in the absence of injury. Protein-protein interaction studies demonstrate that the SAM domains are necessary and sufficient to mediate SARM-SARM binding. SARM mutants lacking a TIR domain bind full-length SARM and exhibit strong dominant-negative activity. These results indicate that SARM plays an integral role in the dismantling of injured axons and support a model in which SAM-mediated multimerization is necessary for TIR-dependent engagement of a downstream destruction pathway. These findings suggest that inhibitors of SAM and TIR interactions represent therapeutic candidates for blocking pathological axon loss and neuronal cell death.

  13. Observational constraints on the response function of Southern Ocean SST to SAM forcing

    NASA Astrophysics Data System (ADS)

    Hausmann, U.; Ferreira, D.; Marshall, J.

    2015-12-01

    Recent coupled model studies of the polar Southern Ocean (SO) revealed an initial (fast) cooling, but longer-term (slow) and equilibrium warming, of sea surface temperature (SST) in response to stratospheric ozone depletion and the concurrent shift of the Southern Annular Mode (SAM) to its positive phase. Yet there is much spread across models in the amplitude and time scale of the equilibration, so that even the sign of the implied recent-decade SST response to ozone depletion is not robust. Here we use the framework of a simple layered model (representing mixed layer, seasonal thermocline and upper permanent thermocline of the SO south of the polar front) combined with observations of the SO, to derive constraints on the equilibrium response of the real-world SO to annually-repeating seasonal SAM forcing. We obtain simple expressions for the equilibrium response in terms of the SAM-induced air-sea fluxes of heat and momentum and the SO horizontal and vertical temperature stratifications. These are then evaluated using satellite observations and atmospheric reanalysis data, as well as in-situ ocean climatologies. Our estimates suggest that, for observed characteristics (mixed layer depths, stratification, phasing of the SAM-forcing in season and space), the well-documented surface-forced fast SO SST cooling is large in comparison to the dynamically-induced subsurface-forced warming, and thus also largely sets the sign and amplitude of the equilibrium response.Exploration of the parameter space of coupled model versus observed ratios of horizontal to vertical stratifications provides a rationale for the discrepant equilibrium responses.

  14. 18. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, ...

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

    18. (4"X5" image enlarged from 2 1/4" negative) Sam Fowler, Photographer, February 1998 VIEW OF GEORGIA DOT BRIDGE NO. 051-00025D-01986N (JAMES P. HOULIHAN BRIDGE) APPROACH SPAN FENDER. DOLPHIN LOCATED AT RIGHT. NAVIGATIONAL LIGHT LOCATED ON TOP OF FENDER - Georgia DOT Bridge No. 051-00025D-01986N, US 17 & State Route 25 Spanning Savannah River, Port Wentworth, Chatham County, GA

  15. Parabolic Trough Collector Cost Update for the System Advisor Model (SAM)

    SciTech Connect

    Kurup, Parthiv; Turchi, Craig S.

    2015-11-01

    This report updates the baseline cost for parabolic trough solar fields in the United States within NREL's System Advisor Model (SAM). SAM, available at no cost at https://sam.nrel.gov/, is a performance and financial model designed to facilitate decision making for people involved in the renewable energy industry. SAM is the primary tool used by NREL and the U.S. Department of Energy (DOE) for estimating the performance and cost of concentrating solar power (CSP) technologies and projects. The study performed a bottom-up build and cost estimate for two state-of-the-art parabolic trough designs -- the SkyTrough and the Ultimate Trough. The SkyTrough analysis estimated the potential installed cost for a solar field of 1500 SCAs as $170/m2 +/- $6/m2. The investigation found that SkyTrough installed costs were sensitive to factors such as raw aluminum alloy cost and production volume. For example, in the case of the SkyTrough, the installed cost would rise to nearly $210/m2 if the aluminum alloy cost was $1.70/lb instead of $1.03/lb. Accordingly, one must be aware of fluctuations in the relevant commodities markets to track system cost over time. The estimated installed cost for the Ultimate Trough was only slightly higher at $178/m2, which includes an assembly facility of $11.6 million amortized over the required production volume. Considering the size and overall cost of a 700 SCA Ultimate Trough solar field, two parallel production lines in a fully covered assembly facility, each with the specific torque box, module and mirror jigs, would be justified for a full CSP plant.

  16. Experience producing simulated events for the DZero experiment on the SAM-Grid

    SciTech Connect

    Garzoglio, G.; Terekhov, I.; Snow, J.; Jain, S.; Nishandar, A.; /Texas U., Arlington

    2004-12-01

    Most of the simulated events for the DZero experiment at Fermilab have been historically produced by the ''remote'' collaborating institutions. One of the principal challenges reported concerns the maintenance of the local software infrastructure, which is generally different from site to site. As the understanding of the distributed computing community over distributively owned and shared resources progresses, the adoption of grid technologies to address the production of Monte Carlo events for high energy physics experiments becomes increasingly interesting. SAM-Grid is a software system developed at Fermilab, which integrates standard grid technologies for job and information management with SAM, the data handling system of the DZero and CDF experiments. During the past few months, this grid system has been tailored for the Monte Carlo production of DZero. Since the initial phase of deployment, this experience has exposed an interesting series of requirements to the SAM-Grid services, the standard middleware, the resources and their management and to the analysis framework of the experiment. As of today, the inefficiency due to the grid infrastructure has been reduced to as little as 1%. In this paper, we present our statistics and the ''lessons learned'' in running large high energy physics applications on a grid infrastructure.

  17. Major Volatiles from MSL SAM Evolved Gas Analyses: Yellowknife Bay Through Lower Mount Sharp

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Archer, P. D., Jr.; Sutter, B.; Franz, H. B.; Eigenbrode, J. L.; Ming, D. W.; Morris, R. V.; Niles, P. B.; Stern, J. C.; Freissinet, C.; Glavin, D. P.; Atreya, S. K.; Bish, D. L.; Blake, D. F.; Mahaffy, P. R.; Navarro-Gonzalez, R.; McKay, C. P.; Wilhelm, M. B.

    2015-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) analysed several subsamples of <150 µm fines from five sites at Gale Crater. Three were in Yellowknife Bay: the Rocknest aeolian bedform ("RN") and drilled Sheepbed mudstone from sites John Klein ("JK") and Cumberland ("CB"). One was drilled from the Windjana ("WJ") site on a sandstone of the Kimberly formation investigated on route to Mount Sharp. Another was drilled from the Confidence Hills ("CH") site on a sandstone of the Murray Formation at the base of Mt. Sharp (Pahrump Hills). Outcrops are sedimentary rocks that are largely of fluvial or lacustrine origin, with minor aeolian deposits.. SAM's evolved gas analysis (EGA) mass spectrometry detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases, including organic fragments. The identity and evolution temperature (T) of evolved gases can support CheMin mineral detection and place constraints on trace volatile-bearing phases or phases difficult to characterize with XRD (e.g., X-ray amorphous phases). They can also give constraints on sample organic chemistry. Here, we discuss trends in major evolved volatiles from SAM EGA analyses to date.

  18. SAM: speech-aware applications in medicine to support structured data entry.

    PubMed

    Wormek, A K; Ingenerf, J; Orthner, H F

    1997-01-01

    In the last two years, improvement in speech recognition technology has directed the medical community's interest to porting and using such innovations in clinical systems. The acceptance of speech recognition systems in clinical domains increases with recognition speed, large medical vocabulary, high accuracy, continuous speech recognition, and speaker independence. Although some commercial speech engines approach these requirements, the greatest benefit can be achieved in adapting a speech recognizer to a specific medical application. The goals of our work are first, to develop a speech-aware core component which is able to establish connections to speech recognition engines of different vendors. This is realized in SAM. Second, with applications based on SAM we want to support the physician in his/her routine clinical care activities. Within the STAMP project (STAndardized Multimedia report generator in Pathology), we extend SAM by combining a structured data entry approach with speech recognition technology. Another speech-aware application in the field of Diabetes care is connected to a terminology server. The server delivers a controlled vocabulary which can be used for speech recognition.

  19. SAM 2 Measurements of the Polar Stratospheric Aerosol, volume 2. April 1979 to October 1979

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Steele, H. M.; Hamill, P.

    1982-01-01

    The Stratospheric Aerosol Measurement (SAM) II sensor is abroad the Earth orbiting Nimbus 7 spacecraft proving extinction measurements of the Antarctic and Arctic stratospheric aerosol with a vertical resolution of 1 km. Representative examples and weekly averages of aerosol data and corresponding temperature profiles for the time and place of each SAM II measurement (April 29, 1979, to October 27, 1979) is presented. Contours of aerosol extinction as a function of altitude and longitude or time were plotted and weekly aerosol optical depths were calculated. Seasonal variations and variations in space (altitude and longitude) for both polar regions are easily seen. Typical values of aerosol extinction at the SAM II wavelength of 1.0 micron for the time priod were 1 to 3 x 10 to the -4th power km -1 in the main stratospheric aerosol layer. Optical depths for the stratosphere were about 0.002. Polar stratospheric clouds at altitudes between the tropopause and 20 km were observed during the Antarctic winter at various times and locations. A ready-to-use format containing a representative sample of the second 6 months of data to be used in atmospheric and climatic studies is presented.

  20. Integration, Validation, and Application of a PV Snow Coverage Model in SAM

    SciTech Connect

    Ryberg, David; Freeman, Janine

    2015-09-01

    Due to the increasing deployment of PV systems in snowy climates, there is significant interest in a method capable of estimating PV losses resulting from snow coverage that has been verified for a wide variety of system designs and locations. A scattering of independent snow coverage models have been developed over the last 15 years; however, there has been very little effort spent on verifying these models beyond the system design and location on which they were based. Moreover, none of the major PV modeling software products have incorporated any of these models into their workflow. In response to this deficiency, we have integrated the methodology of the snow model developed in the paper by Marion et al. [1] into the National Renewable Energy Laboratory's (NREL) System Advisor Model (SAM). In this work we describe how the snow model is implemented in SAM and discuss our demonstration of the model's effectiveness at reducing error in annual estimations for two PV arrays. Following this, we use this new functionality in conjunction with a long term historical dataset to estimate average snow losses across the United States for a typical PV system design. The open availability of the snow loss estimation capability in SAM to the PV modeling community, coupled with our results of the nation-wide study, will better equip the industry to accurately estimate PV energy production in areas affected by snowfall.

  1. Background and Artifacts Generated by the by the Sample Preparation Experiment on SAM

    NASA Astrophysics Data System (ADS)

    Belmahdi, Imene; Buch, Arnaud; Szopa, Cyril; Freissinet, Caroline; Glavin, Daniel; Coll, Patrice; Cabane, Michel; Millan, Maeva; Eigenbrode, Jennifer; Navarro-Gonzalez, Rafael; Stern, Jennifer; Coscia, David; Bonnet, Jean-Yves; Teinturier, Samuel; Morisson, Marietta; Stambouli, Moncef; Dequaire, Tristan; Mahaffy, Paul

    2016-04-01

    Sample Analysis at Mars (SAM) is one of the instruments of the Mars Science Laboratory mission. Three analytical devices composed the SAM experiment: the Tunable Laser Spectrometer (TLS), the Gas Chromatography (GC) and the Mass Spectrometer (MS). To adapt the nature of a sample to the analytical devices used, a sample preparation and gas processing system implemented with (a) a pyrolysis system, (b) wet chemistry: MTBSTFA and TMAH (c) the hydrocarbon trap (silica beads, Tenax® TA and Carbosieve G) and the injection trap (Tenax® GR composed of Tenax® TA and 30% of graphite) are employed to concentrate volatiles released from the sample prior to GC-MS analysis. Our study investigates several propositions for chlorinated hydrocarbon formation detected in the SAM background by looking for: (a) all products coming from the interaction of Tenax® and perchlorates present on Mars, (b) also between some soil sample and perchlorates and (c) sources of chlorinated hydrocarbon precursors. Here we report on the detection of chlorohydrocarbon compounds and their potential origin.

  2. Serine and SAM Responsive Complex SESAME Regulates Histone Modification Crosstalk by Sensing Cellular Metabolism.

    PubMed

    Li, Shanshan; Swanson, Selene K; Gogol, Madelaine; Florens, Laurence; Washburn, Michael P; Workman, Jerry L; Suganuma, Tamaki

    2015-11-05

    Pyruvate kinase M2 (PKM2) is a key enzyme for glycolysis and catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate, which supplies cellular energy. PKM2 also phosphorylates histone H3 threonine 11 (H3T11); however, it is largely unknown how PKM2 links cellular metabolism to chromatin regulation. Here, we show that the yeast PKM2 homolog, Pyk1, is a part of a novel protein complex named SESAME (Serine-responsive SAM-containing Metabolic Enzyme complex), which contains serine metabolic enzymes, SAM (S-adenosylmethionine) synthetases, and an acetyl-CoA synthetase. SESAME interacts with the Set1 H3K4 methyltransferase complex, which requires SAM synthesized from SESAME, and recruits SESAME to target genes, resulting in phosphorylation of H3T11. SESAME regulates the crosstalk between H3K4 methylation and H3T11 phosphorylation by sensing glycolysis and glucose-derived serine metabolism. This leads to auto-regulation of PYK1 expression. Thus, our study provides insights into the mechanism of regulating gene expression, responding to cellular metabolism via chromatin modifications.

  3. SAM: speech-aware applications in medicine to support structured data entry.

    PubMed Central

    Wormek, A. K.; Ingenerf, J.; Orthner, H. F.

    1997-01-01

    In the last two years, improvement in speech recognition technology has directed the medical community's interest to porting and using such innovations in clinical systems. The acceptance of speech recognition systems in clinical domains increases with recognition speed, large medical vocabulary, high accuracy, continuous speech recognition, and speaker independence. Although some commercial speech engines approach these requirements, the greatest benefit can be achieved in adapting a speech recognizer to a specific medical application. The goals of our work are first, to develop a speech-aware core component which is able to establish connections to speech recognition engines of different vendors. This is realized in SAM. Second, with applications based on SAM we want to support the physician in his/her routine clinical care activities. Within the STAMP project (STAndardized Multimedia report generator in Pathology), we extend SAM by combining a structured data entry approach with speech recognition technology. Another speech-aware application in the field of Diabetes care is connected to a terminology server. The server delivers a controlled vocabulary which can be used for speech recognition. PMID:9357730

  4. Determinants of tRNA Recognition by the Radical SAM Enzyme RlmN

    PubMed Central

    Fitzsimmons, Christina M.; Fujimori, Danica Galonić

    2016-01-01

    RlmN, a bacterial radical SAM methylating enzyme, has the unusual ability to modify two distinct types of RNA: 23S rRNA and tRNA. In rRNA, RlmN installs a methyl group at the C2 position of A2503 of 23S rRNA, while in tRNA the modification occurs at nucleotide A37, immediately adjacent to the anticodon triplet. Intriguingly, only a subset of tRNAs that contain an adenosine at position 37 are substrates for RlmN, suggesting that the enzyme carefully probes the highly conserved tRNA fold and sequence features to identify its targets. Over the past several years, multiple studies have addressed rRNA modification by RlmN, while relatively few investigations have focused on the ability of this enzyme to modify tRNAs. In this study, we utilized in vitro transcribed tRNAs as model substrates to interrogate RNA recognition by RlmN. Using chimeras and point mutations, we probed how the structure and sequence of RNA influences methylation, identifying position 38 of tRNAs as a critical determinant of substrate recognition. We further demonstrate that, analogous to previous mechanistic studies with fragments of 23S rRNA, tRNA methylation requirements are consistent with radical SAM reactivity. Together, our findings provide detailed insight into tRNA recognition by a radical SAM methylating enzyme. PMID:27902775

  5. SAMSVM: A tool for misalignment filtration of SAM-format sequences with support vector machine.

    PubMed

    Yang, Jianfeng; Ding, Xiaofan; Sun, Xing; Tsang, Shui-Ying; Xue, Hong

    2015-12-01

    Sequence alignment/map (SAM) formatted sequences [Li H, Handsaker B, Wysoker A et al., Bioinformatics 25(16):2078-2079, 2009.] have taken on a main role in bioinformatics since the development of massive parallel sequencing. However, because misalignment of sequences poses a significant problem in analysis of sequencing data that could lead to false positives in variant calling, the exclusion of misaligned reads is a necessity in analysis. In this regard, the multiple features of SAM-formatted sequences can be treated as vectors in a multi-dimension space to allow the application of a support vector machine (SVM). Applying the LIBSVM tools developed by Chang and Lin [Chang C-C, Lin C-J, ACM Trans Intell Syst Technol 2:1-27, 2011.] as a simple interface for support vector classification, the SAMSVM package has been developed in this study to enable misalignment filtration of SAM-formatted sequences. Cross-validation between two simulated datasets processed with SAMSVM yielded accuracies that ranged from 0.89 to 0.97 with F-scores ranging from 0.77 to 0.94 in 14 groups characterized by different mutation rates from 0.001 to 0.1, indicating that the model built using SAMSVM was accurate in misalignment detection. Application of SAMSVM to actual sequencing data resulted in filtration of misaligned reads and correction of variant calling.

  6. SAMS Acceleration Measurements on Mir From January to May 1997 (NASA Increment 4)

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard

    1998-01-01

    During NASA Increment 4 (January to May 1997), about 5 gigabytes of acceleration data were collected by the Space Acceleration Measurements System (SAMS) onboard the Russian Space Station, Mir. The data were recorded on 28 optical disks which were returned to Earth on STS-84. During this increment, SAMS data were collected in the Priroda module to support the Mir Structural Dynamics Experiment (MiSDE), the Binary Colloidal Alloy Tests (BCAT), Angular Liquid Bridge (ALB), Candle Flames in Microgravity (CFM), Diffusion Controlled Apparatus Module (DCAM), Enhanced Dynamic Load Sensors (EDLS), Forced Flow Flame Spreading Test (FFFT), Liquid Metal Diffusion (LMD), Protein Crystal Growth in Dewar (PCG/Dewar), Queen's University Experiments in Liquid Diffusion (QUELD), and Technical Evaluation of MIM (TEM). This report points out some of the salient features of the microgravity environment to which these experiments were exposed. Also documented are mission events of interest such as the docked phase of STS-84 operations, a Progress engine burn, Soyuz vehicle docking and undocking, and Progress vehicle docking. This report presents an overview of the SAMS acceleration measurements recorded by 10 Hz and 100 Hz sensor heads. The analyses included herein complement those presented in previous summary reports prepared by the Principal Investigator Microgravity Services (PIMS) group.

  7. A magnesium-induced triplex pre-organizes the SAM-II riboswitch

    PubMed Central

    Roy, Susmita; Lammert, Heiko; Dayie, T. Kwaku; Sanbonmatsu, Karissa Y.

    2017-01-01

    Our 13C- and 1H-chemical exchange saturation transfer (CEST) experiments previously revealed a dynamic exchange between partially closed and open conformations of the SAM-II riboswitch in the absence of ligand. Here, all-atom structure-based molecular simulations, with the electrostatic effects of Manning counter-ion condensation and explicit magnesium ions are employed to calculate the folding free energy landscape of the SAM-II riboswitch. We use this analysis to predict that magnesium ions remodel the landscape, shifting the equilibrium away from the extended, partially unfolded state towards a compact, pre-organized conformation that resembles the ligand-bound state. Our CEST and SAXS experiments, at different magnesium ion concentrations, quantitatively confirm our simulation results, demonstrating that magnesium ions induce collapse and pre-organization. Agreement between theory and experiment bolsters microscopic interpretation of our simulations, which shows that triplex formation between helix P2b and loop L1 is highly sensitive to magnesium and plays a key role in pre-organization. Pre-organization of the SAM-II riboswitch allows rapid detection of ligand with high selectivity, which is important for biological function. PMID:28248966

  8. Tribological properties of self-assembled monolayers of catecholic imidazolium and the spin-coated films of ionic liquids.

    PubMed

    Liu, Jianxi; Li, Jinlong; Yu, Bo; Ma, Baodong; Zhu, Yangwen; Song, Xinwang; Cao, Xulong; Yang, Wu; Zhou, Feng

    2011-09-20

    A novel compound of an imidazolium type of ionic liquid (IL) containing a biomimetic catecholic functional group normally seen in mussel adhesive proteins was synthesized. The IL can be immobilized on a silicon surface and a variety of other engineering material surfaces via the catecholic anchor, allowing the tribological protection of these substrates for engineering applications. The surface wetting and adhesive properties and the tribological property of the synthesized self-assembled monolayers (SAMs) are successfully modulated by altering the counteranions. The chemical composition and wettability of the IL SAMs were characterized by means of X-ray photoelectron spectroscopy (XPS) and contact angle (CA) measurements. The adhesive and friction forces were measured with an atomic force microscope (AFM) on the nanometer scale. IL composite films were prepared by spin coating thin IL films on top of the SAMs. The macrotribological properties of these IL composite films were investigated with a pin-on-disk tribometer. The results indicate that the presence of IL SAMs on a surface can improve the wettability of spin-coated ionic liquids and thus the film quality and the tribological properties. These films registered a reduced friction coefficient and a significantly enhanced durability and load-carrying capacity. The tribological properties of the composite films are better than those of pure IL films because the presence of the monolayers improves the adhesion and compatibility of spin-coated IL films with substrates.

  9. Electrochemical Properties of a Thiol Monolayers Coated Gold Electrode Modified with Osmium Gel Membrane as Enzyme Sensor

    NASA Astrophysics Data System (ADS)

    Yabutani, Tomoki; Okada, Nobuyuki; Maruyama, Kenichi; Motonaka, Junko

    The electrochemical behavior of an enzyme sensor for glucose using a gold electrode modified with thiol self-assembled membrane and osmium complex gel as an electron transferring mediator has further been investigated by electrochemical analysis. The gold electrode was initially coated with aminomethanethiol self assembling mono layer membrane(thiol-SAM) and then immobilized with glucose oxidase using poly(vinylpyridine-co-allylamine) (PVP-co-AA), gel coordinated with osmium bipyridine complexes (GOD/Os-PVP-co-AA gel). The cleaning condition of the surface of the Au electrode prior to coating thiol SAM was optimized for reduction of interference caused by concomitant compounds. It was found that interfering influence was most efficiently reduced in the case of use of the Au electrode immersed into nitric acid. The current ratio with a thiol coated gold electrode modified with Os-PVP-co-AA gel in glucose solution in the presence to absence of ascorbic acid, acetaminophen, and uric acid (ID+I/II) was 1.006, 1.014, and 1.018, respectively. The peak current response of glucose in the electrode modified with thiol SAM was dropped to 60 98% as compared with that without thiol SAM.

  10. Conformational heterogeneity of the SAM-I riboswitch transcriptional ON state: a chaperone-like role for S-adenosyl methionine.

    PubMed

    Huang, Wei; Kim, Joohyun; Jha, Shantenu; Aboul-Ela, Fareed

    2012-05-18

    Riboswitches are promising targets for the design of novel antibiotics and engineering of portable genetic regulatory elements. There is evidence that variability in riboswitch properties allows tuning of expression for genes involved in different stages of biosynthetic pathways by mechanisms that are not currently understood. Here, we explore the mechanism for tuning of S-adenosyl methionine (SAM)-I riboswitch folding. Most SAM-I riboswitches function at the transcriptional level by sensing the cognate ligand SAM. SAM-I riboswitches orchestrate the biosynthetic pathways of cysteine, methionine, SAM, and so forth. We use base-pair probability predictions to examine the secondary-structure folding landscape of several SAM-I riboswitch sequences. We predict different folding behaviors for different SAM-I riboswitch sequences. We identify several "decoy" base-pairing interactions involving 5' riboswitch residues that can compete with the formation of a P1 helix, a component of the ligand-bound "transcription OFF" state, in the absence of SAM. We hypothesize that blockage of these interactions through SAM contacts contributes to stabilization of the OFF state in the presence of ligand. We also probe folding patterns for a SAM-I riboswitch RNA using constructs with different 3' truncation points experimentally. Folding was monitored through fluorescence, susceptibility to base-catalyzed cleavage, nuclear magnetic resonance, and indirectly through SAM binding. We identify key decision windows at which SAM can affect the folding pathway towards the OFF state. The presence of decoy conformations and differential sensitivities to SAM at different transcript lengths is crucial for SAM-I riboswitches to modulate gene expression in the context of global cellular metabolism.

  11. Nuclear Protein Sam68 Interacts with the Enterovirus 71 Internal Ribosome Entry Site and Positively Regulates Viral Protein Translation

    PubMed Central

    Zhang, Hua; Song, Lei; Cong, Haolong

    2015-01-01

    ABSTRACT Enterovirus 71 (EV71) recruits various cellular factors to assist in the replication and translation of its genome. Identification of the host factors involved in the EV71 life cycle not only will enable a better understanding of the infection mechanism but also has the potential to be of use in the development of antiviral therapeutics. In this study, we demonstrated that the cellular factor 68-kDa Src-associated protein in mitosis (Sam68) acts as an internal ribosome entry site (IRES) trans-acting factor (ITAF) that binds specifically to the EV71 5′ untranslated region (5′UTR). Interaction sites in both the viral IRES (stem-loops IV and V) and the heterogeneous nuclear ribonucleoprotein K homology (KH) domain of Sam68 protein were further mapped using an electrophoretic mobility shift assay (EMSA) and biotin RNA pulldown assay. More importantly, dual-luciferase (firefly) reporter analysis suggested that overexpression of Sam68 positively regulated IRES-dependent translation of virus proteins. In contrast, both IRES activity and viral protein translation significantly decreased in Sam68 knockdown cells compared with the negative-control cells treated with short hairpin RNA (shRNA). However, downregulation of Sam68 did not have a significant inhibitory effect on the accumulation of the EV71 genome. Moreover, Sam68 was redistributed from the nucleus to the cytoplasm and interacts with cellular factors, such as poly(rC)-binding protein 2 (PCBP2) and poly(A)-binding protein (PABP), during EV71 infection. The cytoplasmic relocalization of Sam68 in EV71-infected cells may be involved in the enhancement of EV71 IRES-mediated translation. Since Sam68 is known to be a RNA-binding protein, these results provide direct evidence that Sam68 is a novel ITAF that interacts with EV71 IRES and positively regulates viral protein translation. IMPORTANCE The nuclear protein Sam68 is found as an additional new host factor that interacts with the EV71 IRES during infection

  12. Versatile Coating

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A radome at Logan Airport and a large parabolic antenna at the Wang Building in Massachusetts are protected from weather, corrosion and ultraviolet radiation by a coating, specially designed for antennas and radomes, known as CRC Weathertite 6000. The CRC 6000 line that emerged from Boyd Coatings Research Co., Inc. is a solid dispersion of fluorocarbon polymer and polyurethane that yields a tough, durable film with superior ultraviolet resistance and the ability to repel water and ice over a long term. Additionally, it provides resistance to corrosion, abrasion, chemical attacks and impacts. Material can be used on a variety of substrates, such as fiberglass, wood, plastic and concrete in addition to steel and aluminum. In addition Boyd Coatings sees CRC 6000 applicability as an anti-icing system coated on the leading edge of aircraft wings.

  13. Protective Coating

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Inorganic Coatings, Inc.'s K-Zinc 531 protective coating is water-based non-toxic, non-flammable and has no organic emissions. High ratio silicate formula bonds to steel, and in 30 minutes, creates a very hard ceramic finish with superior adhesion and abrasion resistance. Improved technology allows application over a minimal commercial sandblast, fast drying in high humidity conditions and compatibility with both solvent and water-based topcoats. Coating is easy to apply and provides long term protection with a single application. Zinc rich coating with water-based potassium silicate binder offers cost advantages in materials, labor hours per application, and fewer applications over a given time span.

  14. Evidence for Perchlorates and the Origin of Chlorinated Hydrocarbons Detected by SAM at the Rocknest Aeolian Deposit in Gale Crater

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Freissinet, Caroline; Miller, Kristen E.; Eigenbrode, Jennifer L.; Brunner, Anna E.; Buch, Arnaud; Sutter, Brad; Archer, P. Douglas, Jr.; Atreya, Sushil K.; Brinckerhoff, William B.; Cabane, Michel; Coll, Patrice; Conrad, Pamela G.; Coscia, David; Dworkin, Jason P.; Franz, Heather B.; Grotzinger, John P.; Leshin, Laurie A.; Martin, Mildred G.; McKay, Christopher; Ming, Douglas W.; Navarro-Gonzalez, Rafael; Pavlov, Alexander; Steele, Andrew; Summons, Roger E.; Szopa, Cyril; Teinturier, Samuel; Mahaffy, Paul R.

    2013-01-01

    A single scoop of the Rocknest aeolian deposit was sieved (less than 150 micrometers), and four separate sample portions, each with a mass of approximately 50 mg, were delivered to individual cups inside the Sample Analysis at Mars (SAM) instrument by the Mars Science Laboratory rover's sample acquisition system. The samples were analyzed separately by the SAM pyrolysis evolved gas and gas chromatograph mass spectrometer analysis modes. Several chlorinated hydrocarbons including chloromethane, dichloromethane, trichloromethane, a chloromethylpropene, and chlorobenzene were identified by SAM above background levels with abundances of approximately 0.01 to 2.3 nmol. The evolution of the chloromethanes observed during pyrolysis is coincident with the increase in O2 released from the Rocknest sample and the decomposition of a product of N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA), a chemical whose vapors were released from a derivatization cup inside SAM. The best candidate for the oxychlorine compounds in Rocknest is a hydrated calcium perchlorate (Ca(ClO4)2·nH2O), based on the temperature release of O2 that correlates with the release of the chlorinated hydrocarbons measured by SAM, although other chlorine-bearing phases are being considered. Laboratory analog experiments suggest that the reaction of Martian chlorine from perchlorate decomposition with terrestrial organic carbon from MTBSTFA during pyrolysis can explain the presence of three chloromethanes and a chloromethylpropene detected by SAM. Chlorobenzene may be attributed to reactions of Martian chlorine released during pyrolysis with terrestrial benzene or toluene derived from 2,6-diphenylphenylene oxide (Tenax) on the SAM hydrocarbon trap. At this time we do not have definitive evidence to support a nonterrestrial carbon source for these chlorinated hydrocarbons, nor do we exclude the possibility that future SAM analyses will reveal the presence of organic compounds native to the

  15. A Study of the Effects of Sensor Noise and Guidance Laws on SAM Effectiveness Against Cruise Missiles

    DTIC Science & Technology

    2015-06-01

    EFFECTS OF SENSOR NOISE AND GUIDANCE LAWS ON SAM EFFECTIVENESS AGAINST CRUISE MISSILES by Murat Dogen June 2015 Thesis Advisor: Robert G...2015 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE A STUDY OF THE EFFECTS OF SENSOR NOISE AND GUIDANCE LAWS ON SAM...EFFECTIVENESS AGAINST CRUISE MISSILES 5. FUNDING NUMBERS 6. AUTHOR( S ) Murat DOGEN 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval

  16. Evidence for perchlorates and the origin of chlorinated hydrocarbons detected by SAM at the Rocknest aeolian deposit in Gale Crater

    NASA Astrophysics Data System (ADS)

    Glavin, Daniel P.; Freissinet, Caroline; Miller, Kristen E.; Eigenbrode, Jennifer L.; Brunner, Anna E.; Buch, Arnaud; Sutter, Brad; Archer, P. Douglas; Atreya, Sushil K.; Brinckerhoff, William B.; Cabane, Michel; Coll, Patrice; Conrad, Pamela G.; Coscia, David; Dworkin, Jason P.; Franz, Heather B.; Grotzinger, John P.; Leshin, Laurie A.; Martin, Mildred G.; McKay, Christopher; Ming, Douglas W.; Navarro-González, Rafael; Pavlov, Alexander; Steele, Andrew; Summons, Roger E.; Szopa, Cyril; Teinturier, Samuel; Mahaffy, Paul R.

    2013-10-01

    A single scoop of the Rocknest aeolian deposit was sieved (< 150 µm), and four separate sample portions, each with a mass of ~50 mg, were delivered to individual cups inside the Sample Analysis at Mars (SAM) instrument by the Mars Science Laboratory rover's sample acquisition system. The samples were analyzed separately by the SAM pyrolysis evolved gas and gas chromatograph mass spectrometer analysis modes. Several chlorinated hydrocarbons including chloromethane, dichloromethane, trichloromethane, a chloromethylpropene, and chlorobenzene were identified by SAM above background levels with abundances of ~0.01 to 2.3 nmol. The evolution of the chloromethanes observed during pyrolysis is coincident with the increase in O2 released from the Rocknest sample and the decomposition of a product of N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA), a chemical whose vapors were released from a derivatization cup inside SAM. The best candidate for the oxychlorine compounds in Rocknest is a hydrated calcium perchlorate (Ca(ClO4)2·nH2O), based on the temperature release of O2 that correlates with the release of the chlorinated hydrocarbons measured by SAM, although other chlorine-bearing phases are being considered. Laboratory analog experiments suggest that the reaction of Martian chlorine from perchlorate decomposition with terrestrial organic carbon from MTBSTFA during pyrolysis can explain the presence of three chloromethanes and a chloromethylpropene detected by SAM. Chlorobenzene may be attributed to reactions of Martian chlorine released during pyrolysis with terrestrial benzene or toluene derived from 2,6-diphenylphenylene oxide (Tenax) on the SAM hydrocarbon trap. At this time we do not have definitive evidence to support a nonterrestrial carbon source for these chlorinated hydrocarbons, nor do we exclude the possibility that future SAM analyses will reveal the presence of organic compounds native to the Martian regolith.

  17. The Seismic Aftershock Monitoring System (SAMS) for OSI - Experiences from IFE14

    NASA Astrophysics Data System (ADS)

    Gestermann, Nicolai; Sick, Benjamin; Häge, Martin; Blake, Thomas; Labak, Peter; Joswig, Manfred

    2016-04-01

    An on-site inspection (OSI) is the third of four elements of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The sole purpose of an OSI is to confirm whether a nuclear weapon test explosion or any other nuclear explosion has been carried out in violation of the treaty and to gather any facts which might assist in identifying any possible violator. It thus constitutes the final verification measure under the CTBT if all other available measures are not able to confirm the nature of a suspicious event. The Provisional Technical Secretariat (PTS) carried out the Integrated Field Exercise 2014 (IFE14) in the Dead Sea Area of Jordan from 3 November to 9. December 2014. It was a fictitious OSI whose aim was to test the inspection capabilities in an integrated manner. The technologies allowed during an OSI are listed in the Treaty. The aim of the Seismic Aftershock Monitoring System (SAMS) is to detect and localize aftershocks of low magnitudes of the triggering event or collapses of underground cavities. The locations of these events are expected in the vicinity of a possible previous explosion and help to narrow down the search area within an inspection area (IA) of an OSI. The success of SAMS depends on the main elements, hardware, software, deployment strategy, the search logic and not least the effective use of personnel. All elements of SAMS were tested and improved during the Built-Up Exercises (BUE) which took place in Austria and Hungary. IFE14 provided more realistic climatic and hazardous terrain conditions with limited resources. Significant variations in topography of the IA of IFE14 in the mountainous Dead Sea Area of Jordan led to considerable challenges which were not expected from experiences encountered during BUE. The SAMS uses mini arrays with an aperture of about 100 meters and with a total of 4 elements. The station network deployed during IFE14 and results of the data analysis will be presented. Possible aftershocks of

  18. First results from the CheMin, DAN and SAM instruments on Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Blake, D. F.; Mahaffy, P. R.; Mitrofanov, I.

    2012-12-01

    One of the principal goals of the Mars Science Laboratory rover Curiosity is to identify and characterize the early habitable environments of Mars, as recorded in the stratified rocks and soil of Gale crater. The suite of instruments aboard Curiosity will make measurements useful for determining the presence and lateral/vertical distribution of hydrated phases, the mineralogy and "preservation potential" of sediments and rocks, and the identity and isotopic composition of organic and other carbon containing molecules, should such be present. Three of Curiosity's instruments, DAN ("Dynamic Albedo of Neutrons," a soil hydrogen detector), CheMin ("Chemistry and Mineralogy," a mineralogy instrument) and SAM ("Surface Analysis at Mars," an organic molecule and isotopic analysis instrument) are uniquely suited to this purpose. DAN consists of a pulsed neutron generator and neutron detector that will measure the hydrogen content (i.e., hydrated phases, water ice) in the upper meter of the soil. Both passive and active measurements will be obtained, resulting in a meter-scale resolution transect map of near-surface hydrogen along the path of the rover. These measurements will provide context for the mineralogical and organic measurements of drilled and scooped samples analyzed by CheMin and SAM. CheMin, a powder X-ray Diffraction (pXRD) instrument, will determine the mineralogy of scooped soils and powders obtained from drilled rocks. Hydrated minerals will be identified, along with whole-rock mineralogy for characterizing the environment of formation and preservation potential for organic molecules. SAM consists of a sample handling system, a gas chromatograph, a mass spectrometer, and a tunable laser spectrometer. SAM will accept the same powdered rock and soil samples as CheMin, and will measure and identify organic carbon in these samples as well as evolved inorganic gases such as CO2, CH4, and H2O. Isotopic composition of noble gases and several light elements are

  19. Detecting Complex Organic Compounds Using the SAM Wet Chemistry Experiment on Mars

    NASA Astrophysics Data System (ADS)

    Freissinet, C.; Buch, A.; Glavin, D. P.; Brault, A.; Eigenbrode, J. L.; Kashyap, S.; Martin, M. G.; Miller, K.; Mahaffy, P. R.; Team, M.

    2013-12-01

    The search for organic molecules on Mars can provide important first clues of abiotic chemistry and/or extinct or extant biota on the planet. Gas Chromatography Mass Spectrometry (GC-MS) is currently the most relevant space-compatible analytical tool for the detection of organic compounds. Nevertheless, GC separation is intrinsically restricted to volatile molecules, and many molecules of astrobiological interest are chromatographically refractory or polar. To analyze these organics such as amino acids, nucleobases and carboxylic acids in the Martian regolith, an additional derivatization step is required to transform them into volatile derivatives that are amenable to GC analysis. As part of the Sample Analysis at Mars (SAM) experiment onboard Mars Science Laboratory (MSL) Curiosity rover, a single-step protocol of extraction and chemical derivatization with the silylating reagent N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) has been developed to reach a wide range of astrobiology-relevant refractory organic molecules (Mahaffy et al. 2012; Stalport et al. 2012). Seven cups in the SAM instrument are devoted to MTBSTFA derivatization. However, this chemical reaction adds a protective silyl group in place of each labile hydrogen, which makes the molecule non-identifiable in common mass spectra libraries. Therefore, we have created an extended library of mass spectra of MTBSTFA derivatized compounds of interest, considering their potential occurrence in Mars soils. We then looked specifically for MTBSTFA derivatized compounds using the existing and the newly created library, in various Mars analog soils. To enable a more accurate interpretation of the in situ derivatization GC-MS results that will be obtained by SAM, the lab experiments were performed as close as possible to the SAM flight instrument experimental conditions. Our first derivatization experiments display promising results, the laboratory system permitting an extraction and detection

  20. Evidence for Smectite Clays from MSL SAM Analyses of Mudstone at Yellowknife Bay, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    McAdam, A.; Franz, H.; Mahaffy, P. R.; Eigenbrode, J. L.; Stern, J. C.; Brunner, A.; Sutter, B.; Archer, P. D.; Ming, D. W.; Morris, R. V.; Atreya, S. K.; Team, M.

    2013-12-01

    Drilled samples of mudstone from the Sheepbed unit at Yellowknife Bay were analyzed by MSL instruments including the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments in MSL's Analytical Laboratory. CheMin analyses revealed the first in situ X-ray diffraction based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., saponite) and comprise ~20% of the mudstone sample (e.g., Bristow et al., this meeting). SAM analyses, which heated the mudstone samples to 1000oC and monitored volatiles evolved to perform in situ evolved gas analysis mass spectrometry (EGA-MS), resulted in a H2O trace exhibiting a wide evolution at temperatures <500oC, and an evolution peak at higher temperatures near ~750oC. The low temperature H2O evolution has many potential contributors, including adsorbed H2O, smectite interlayer H2O, and structural H2O/OH from bassanite and akaganeite (identified by CheMin) and H2O/OH from amorphous phases in the sample. The high temperature H2O is consistent with the evolution of H2O from the dehydroxylation of the smectite clay mineral. Comparison to EGA-MS data collected under SAM-like conditions on a variety of clay mineral reference materials indicate that a trioctahedral smectite, such as saponite, is most consistent with the high temperature H2O evolution observed. There may also be SAM EGA-MS evidence for a small high temperature H2O evolution from scoop samples from the Yellowknife Bay Rocknest sand shadow bedform. As in the mudstone samples, this evolution may indicate the detection of smectite clays, and the idea that minor clays may be present in Rocknest materials that could be expected to be at least partially derived from local sources is reasonable. But, because smectite clays were not definitively observed in CheMin analyses of Rocknest materials, they must be present at much lower abundances than the ~20% observed in the mudstone samples. This potential detection underscores the

  1. Evidence for Smectite Clays from MSL SAM Analyses of Mudstone at Yellowknife Bay, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    McAdam, Amy; Franz, Heather; Mahaffy, Paul R.; Eigenbrode, Jennifer L.; Stern, Jennifer C.; Brunner, Anna; Archer, Paul Douglas; Ming, Douglas W.; Morris, Richard V.; Atreya, Sushil K.

    2013-01-01

    Drilled samples of mudstone from the Sheepbed unit at Yellowknife Bay were analyzed by MSL instruments including the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments in MSL's Analytical Laboratory. CheMin analyses revealed the first in situ X-ray diffraction based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., saponite) and comprise approx 20% of the mudstone sample (e.g., Bristow et al., this meeting). SAM analyses, which heated the mudstone samples to 1000 C and monitored volatiles evolved to perform in situ evolved gas analysis mass spectrometry (EGA-MS), resulted in a H2O trace exhibiting a wide evolution at temperatures < 500 C, and an evolution peak at higher temperatures near approx 750 C. The low temperature H2O evolution has many potential contributors, including adsorbed H2O, smectite interlayer H2O, and structural H2O/OH from bassanite and akaganeite (identified by CheMin) and H2O/OH from amorphous phases in the sample. The high temperature H2O is consistent with the evolution of H2O from the dehydroxylation of the smectite clay mineral. Comparison to EGA-MS data collected under SAM-like conditions on a variety of clay mineral reference materials indicate that a trioctahedral smectite, such as saponite, is most consistent with the high temperature H2O evolution observed. There may also be SAM EGA-MS evidence for a small high temperature H2O evolution from scoop samples from the Yellowknife Bay Rocknest sand shadow bedform. As in the mudstone samples, this evolution may indicate the detection of smectite clays, and the idea that minor clays may be present in Rocknest materials that could be expected to be at least partially derived from local sources is reasonable. But, because smectite clays were not definitively observed in CheMin analyses of Rocknest materials, they must be present at much lower abundances than the approx 20% observed in the mudstone samples. This potential detection

  2. CHF Enhancement by Vessel Coating for External Reactor Vessel Cooling

    SciTech Connect

    Fan-Bill Cheung; Joy L. Rempe

    2004-06-01

    In-vessel retention (IVR) is a key severe accident management (SAM) strategy that has been adopted by some operating nuclear power plants and advanced light water reactors (ALWRs). One viable means for IVR is the method of external reactor vessel cooling (ERVC) by flooding of the reactor cavity during a severe accident. As part of a joint Korean – United States International Nuclear Energy Research Initiative (K-INERI), an experimental study has been conducted to investigate the viability of using an appropriate vessel coating to enhance the critical heat flux (CHF) limits during ERVC. Toward this end, transient quenching and steady-state boiling experiments were performed in the SBLB (Subscale Boundary Layer Boiling) facility at Penn State using test vessels with micro-porous aluminum coatings. Local boiling curves and CHF limits were obtained in these experiments. When compared to the corresponding data without coatings, substantial enhancement in the local CHF limits for the case with surface coatings was observed. Results of the steady state boiling experiments showed that micro-porous aluminum coatings were very durable. Even after many cycles of steady state boiling, the vessel coatings remained rather intact, with no apparent changes in color or structure. Moreover, the heat transfer performance of the coatings was found to be highly desirable with an appreciable CHF enhancement in all locations on the vessel outer surface but with very little effect of aging.

  3. Influence of chain ordering on frictional properties of self-assembled monolayers (SAMs) in nano-lubrication.

    PubMed

    Cheng, Hefa; Hu, Yuanan

    2012-01-01

    Adhesion of organic films to substrates is important in applications that involve solid surfaces in sliding contact. Although the thickness of self-assembled monolayers (SAMs) is only a few nanometers, they can drastically modify the frictional properties of the underlying substrate, and thus have great potential for serving as boundary lubricants on micro- and nano-scales. This review focuses on the relationship between the structural and compositional properties of SAMs and their frictional response. Adhesion of SAMs to the substrate surface usually occurs through chemisorption of the head groups on the constituent molecules, with molecular interactions such as van der Waals interactions playing important roles in organizing the molecules into surface films, and in controlling their tribological behavior. The durability and wear resistance of SAMs depend on the nature and strength of the binding forces between the head groups and the substrate surfaces, while the adhesion and friction forces are strongly influenced by the interactions of the terminal groups with the counterfaces. Results from both experimental measurements and molecular dynamics simulations consistently indicate that structural ordering of alkyl chains in SAMs reduces their frictional response, and that SAMs formed by molecules with alkyl chains longer than 8 to 10 methylene units are well organized, exhibiting low levels of friction. Less densely packed or more disordered monolayers inherently possess greater numbers of conformational defects at room temperature and present lower barriers to defect creation under the action of a contacting surface, and thus exhibit higher friction. Cross-linking of the spacer chains can reduce the frictional response of disordered films by increasing the chain ordering, but has little impact on SAMs that are already well ordered. On the other hand, introduction of sterically demanding terminal groups and dissimilar molecules reduces molecular ordering in SAMs

  4. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  5. Loving Sam.

    ERIC Educational Resources Information Center

    Lasky, Kathryn

    1998-01-01

    Describes how the author came to love Mark Twain's writings, taught "Huckleberry Finn" and other of Twain's writings to a ninth-grade class in a Hasidic Jewish Academy, and learned to really love Samuel Clemens. Describes how this love inspired the author to write two books celebrating what she has valued most in 40 years of reading Mark…

  6. Directed immobilization of protein-coated nanospheres to nanometer-scale patterns fabricated by electron beam lithography of poly(ethylene glycol) self-assembled monolayers.

    PubMed

    Rundqvist, Jonas; Hoh, Jan H; Haviland, David B

    2006-05-23

    Controlling the spatial organization of biomolecules on solid supports with high resolution is important for a wide range of scientific and technological problems. Here we report a study of electron beam lithography (EBL) patterning of a self-assembled monolayer (SAM) of the amide-containing poly(ethylene glycol) (PEG) thiol CH(3)O(CH(2)CH(2)O)(17)NHCO(CH(2))(2)SH on Au and demonstrate the patterning of biomolecular features with dimensions approaching 40 nm. The electron dose dependence of feature size and pattern resolution is studied in detail by atomic force microscopy (AFM), which reveals two distinct patterning mechanisms. At low doses, the pattern formation occurs by SAM ablation in a self-developing process where the feature size is directly dose-dependent. At higher doses, electron beam-induced deposition of material, so-called contamination writing, is seen in the ablated areas of the SAM. The balance between these two mechanisms is shown to depend on the geometry of the pattern. The patterned SAMs were backfilled with fluorescent 40-nm spheres coated with NeutrAvidin. These protein-coated spheres adhered to exposed areas in the SAM with high selectivity. This direct writing approach for patterning bioactive surfaces is a fast and efficient way to produce patterns with a resolution approaching that of single proteins.

  7. Nanostructured Coatings

    NASA Astrophysics Data System (ADS)

    Rivière, J.-P.

    In many branches of technology where surfaces are playing a growing role, the use of coatings is often the only way to provide surfaces with specific functional properties. For example, the austenitic stainless steels or titanium alloys exhibit poor resistance to wear and low hardness values, which limits the field of applications. The idea then is to develop new solutions which would improve the mechanical performance and durability of objects used in contact and subjected to mechanical forces in hostile gaseous or liquid environments. Hard coatings are generally much sought after to enhance the resistance to wear and corrosion. They are of particular importance because they constitute a class of protective coatings which is already widely used on an industrial scale to improve the hardness and lifetime of cutting tools.

  8. Protective Coatings

    NASA Technical Reports Server (NTRS)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  9. Evidence for Perchlorates and the Origin of Chlorinated Hydrocarbons Detected by SAM at the Rocknest Aeolian Deposit in Gale Crater

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Freissinet, Caroline; Miller, Kristen E.; Eigenbrode, Jennifer L.; Brunner, Anna E.; Buch, Arnaud; Sutter, Brad; Archer, P. Douglas, Jr.; Atreya, Sushil K.; Brinckerhoff, William B.; Cabane, Michael; Coll, Patrice; Conrad, Pamela G.; Coscia, David; Dworkin, Jason P.; Franz, Heather B.; Grotzinger, John P.; Leshin, Laurie A.; Martin, Mildred G.; McKay, Christopher; Ming, Douglas W.; Navarro-Gonzalez, Rafael; Pavlov, Alexander; Steele, Andrew; Summons, Roger E.; Szopa, Cyril; Teinturier, Samuel; Mahaffy, Paul R.

    2013-01-01

    Four individual sample portions from a single scoop of the Rocknest aeolian deposit were sieved ( 150 m) and delivered to the Sample Analysis at Mars (SAM) instrument by the Mars Science Laboratory rover's sample acquisition system. The samples were analyzed separately by the SAM pyrolysis evolved gas and gas chromatography mass spectrometry analysis modes. Several chlorinated hydrocarbons including chloromethane, dichloromethane, trichloromethane, a chloromethylpropene, and chlorobenzene were identified by SAM above background levels with abundances of 0.01 to 2.3 nanomole.The evolution of the chloromethanes observed during pyrolysis is coincident with the increase in O2 released from the Rocknest sample and the decomposition of a product of N-methyl-N- (tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), a chemical that leaked from a derivatization cup inside SAM.The best candidate for the oxychloride phase in Rocknest is a hydrated calcium perchlorate (Ca(ClO4)2nH2O), based on the temperature release of O2 that correlates with the release of the chlorinated species measured by SAM, although other chlorine bearing phases are being considered. Laboratory pyrolysis experiments suggest that reaction of martian chlorine with organic carbon from MTBSTFA can explain the presence of the chloromethanes and a chloromethylpropene also detected by SAM.However, we cannot exclude the possibility that traces of organic carbon of either martian or exogenous origin contributed to some of the chloromethanes measured by SAM. Although the alteration history and exposure age of the Rocknest deposit is unknown, it is possible that oxidative degradation of complex organic matter by ionizing radiation or other chemical processes in Rocknest has occurred.

  10. Plasmids in different strains of Streptomyces ambofaciens: free and integrated form of plasmid pSAM2.

    PubMed

    Pernodet, J L; Simonet, J M; Guérineau, M

    1984-01-01

    Five strains of Streptomyces ambofaciens were examined for their plasmid content. Among these strains, four belong to the same lineage (strains B) and the other was isolated independently (strain A). A large plasmid (ca. 80 kb), called pSAM1 in this paper and already described, was present in all B strains, and absent in strain A. A second plasmid, not described before, was found as covalently closed circular DNA in two of the four B strains. This plasmid with a size of 11.1 kb was called pSAM2. A restriction map for 14 enzymes was established. Hybridization experiments showed that a unique sequence homologous to this plasmid is integrated in a larger replicon, which is not pSAM1 and is probably the chromosome, in all B strains and not in strain A. It seems probable that the integrated sequence is the origin of the free plasmid found in two strains of the B family. It is noteworthy that the integrated form and the free plasmid may be found together. Transformation experiments proved that pSAM2 may be maintained autonomously in S. ambofaciens strain A and in S. lividans. pSAM2 is a self-transmissible plasmid, able to elicit the lethal zygosis reaction. pSAM2 was compared to the plasmids SLP1, pIJ110 and pIJ408, which all come from integrated sequences in three Streptomyces species and are found as autonomous plasmids after transfer to S. lividans. If pSAM2 resembles these plasmids in its origin, it does not appear to be related directly to them. Concerning their plasmid content, the two isolates of S. ambofaciens are very different.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Application of three-dimensionally area-selective atomic layer deposition for selectively coating the vertical surfaces of standing nanopillars.

    PubMed

    Dong, Wenjing; Zhang, Kenan; Zhang, Yun; Wei, Tiaoxing; Sun, Yan; Chen, Xin; Dai, Ning

    2014-03-25

    We describe a strategy for selectively coating the vertical surfaces of standing nanopillars using area-selective atomic layer deposition (ALD). Hydrophobic self-assembled monolayers (SAMs) are utilised to selectively inhibit the coating of oxides on the modified horizontal regions to ensure that only the vertical surfaces of vertical standing nanorods are coated using ALD processes. This method makes it possible to fabricate vertical nanodevices using a simple process of depositing oxide layer on a vertical surface, and can also be applied to the area-selective surface passivation of other standing structures.

  12. Water-repellent coating: formation of polymeric self-assembled monolayers on nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Cho, Woo Kyung; Park, Sangjin; Jon, Sangyong; Choi, Insung S.

    2007-10-01

    In this paper, we suggest a facile and effective method for water-repellent coating of oxide surfaces. As a coating material, we synthesized a new random copolymer, referred to as poly(TMSMA-r-fluoroMA), by the radical polymerization of 3-(trimethoxysilyl)propyl methacrylate (TMSMA) and a fluoromonomer® bearing methacrylate moiety (fluoroMA). The random copolymer was designed to consist of a 'surface-reactive part' (trimethoxysilyl group) for anchoring onto oxide-based surfaces and a 'functional part' (perfluoro group) for water repellency. The polymeric self-assembled monolayers (pSAMs) of poly(TMSMA-r-fluoroMA) were constructed on three different aluminum oxide substrates, such as flat, concave-textured, and nanoporous plates, and the static water contact angle of each surface before and after the formation of pSAMs was measured. The formation of pSAMs resulted in significantly enhanced hydrophobicity compared with the corresponding bare surfaces. In particular, among three poly(TMSMA-r-fluoroMA)-coated surfaces, the nanoporous plate showed the highest water-repellent property, with a static contact angle of ~163°, which is indicative of superhydrophobic surfaces.

  13. Gold Coating

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Epner Technology Inc. responded to a need from Goddard Space Flight Center for the ultimate in electroplated reflectivity needed for the Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA). Made of beryllium, the MOLA mirror was coated by Epner Technology Laser Gold process, specially improved for the project. Improved Laser Gold- coated reflectors have found use in an epitaxial reactor built for a large semiconductor manufacturer as well as the waveguide in Braun-Thermoscan tympanic thermometer and lasing cavities in various surgical instruments.

  14. Genome Mining for Radical SAM Protein Determinants Reveals Multiple Sactibiotic-Like Gene Clusters

    PubMed Central

    Murphy, Kiera; O'Sullivan, Orla; Rea, Mary C.; Cotter, Paul D.; Ross, R. Paul; Hill, Colin

    2011-01-01

    Thuricin CD is a two-component bacteriocin produced by Bacillus thuringiensis that kills a wide range of clinically significant Clostridium difficile. This bacteriocin has recently been characterized and consists of two distinct peptides, Trnβ and Trnα, which both possess 3 intrapeptide sulphur to α-carbon bridges and act synergistically. Indeed, thuricin CD and subtilosin A are the only antimicrobials known to possess these unusual structures and are known as the sactibiotics (sulplur to alpha carbon-containing antibiotics). Analysis of the thuricin CD-associated gene cluster revealed the presence of genes encoding two highly unusual SAM proteins (TrnC and TrnD) which are proposed to be responsible for these unusual post-translational modifications. On the basis of the frequently high conservation among enzymes responsible for the post-translational modification of specific antimicrobials, we performed an in silico screen for novel thuricin CD–like gene clusters using the TrnC and TrnD radical SAM proteins as driver sequences to perform an initial homology search against the complete non-redundant database. Fifteen novel thuricin CD–like gene clusters were identified, based on the presence of TrnC and TrnD homologues in the context of neighbouring genes encoding potential bacteriocin structural peptides. Moreover, metagenomic analysis revealed that TrnC or TrnD homologs are present in a variety of metagenomic environments, suggesting a widespread distribution of thuricin-like operons in a variety of environments. In-silico analysis of radical SAM proteins is sufficient to identify novel putative sactibiotic clusters. PMID:21760885

  15. Forest Classification Accuracy as Influenced by Multispectral Scanner Spatial Resolution. [Sam Houston National Forest, Texas

    NASA Technical Reports Server (NTRS)

    Nalepka, R. F. (Principal Investigator); Sadowski, F. E.; Sarno, J. E.

    1976-01-01

    The author has identified the following significant results. A supervised classification within two separate ground areas of the Sam Houston National Forest was carried out for two sq meters spatial resolution MSS data. Data were progressively coarsened to simulate five additional cases of spatial resolution ranging up to 64 sq meters. Similar processing and analysis of all spatial resolutions enabled evaluations of the effect of spatial resolution on classification accuracy for various levels of detail and the effects on area proportion estimation for very general forest features. For very coarse resolutions, a subset of spectral channels which simulated the proposed thematic mapper channels was used to study classification accuracy.

  16. A RubisCO like protein links SAM metabolism with isoprenoid biosynthesis

    PubMed Central

    Erb, Tobias J.; Evans, Bradley S.; Cho, Kyuil; Warlick, Benjamin P.; Sriram, Jaya; Wood, B. McKay; Imker, Heidi J.; Sweedler, Jonathan V.; Tabita, F. Robert; Gerlt, John A.

    2012-01-01

    Functional assignment of uncharacterized proteins is a challenge in the era of large-scale genome sequencing. Here, we combine in extracto-NMR, proteomics, and transcriptomics with a newly developed (knock-out) metabolomics platform to determine a potential physiological role for a ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO)-like protein (RLP) from Rhodospirillum rubrum. Our studies unravelled an unexpected link in bacterial central carbon metabolism between S-adenosylmethionine (SAM)-dependent polyamine metabolism and isoprenoid biosynthesis and also provide an alternative approach to assign enzyme function at the organismic level. PMID:23042035

  17. [Research on identification of cabbages and weeds combining spectral imaging technology and SAM taxonomy].

    PubMed

    Zu, Qin; Zhang, Shui-fa; Cao, Yang; Zhao, Hui-yi; Dang, Chang-qing

    2015-02-01

    Weeds automatic identification is the key technique and also the bottleneck for implementation of variable spraying and precision pesticide. Therefore, accurate, rapid and non-destructive automatic identification of weeds has become a very important research direction for precision agriculture. Hyperspectral imaging system was used to capture the hyperspectral images of cabbage seedlings and five kinds of weeds such as pigweed, barnyard grass, goosegrass, crabgrass and setaria with the wavelength ranging from 1000 to 2500 nm. In ENVI, by utilizing the MNF rotation to implement the noise reduction and de-correlation of hyperspectral data and reduce the band dimensions from 256 to 11, and extracting the region of interest to get the spectral library as standard spectra, finally, using the SAM taxonomy to identify cabbages and weeds, the classification effect was good when the spectral angle threshold was set as 0. 1 radians. In HSI Analyzer, after selecting the training pixels to obtain the standard spectrum, the SAM taxonomy was used to distinguish weeds from cabbages. Furthermore, in order to measure the recognition accuracy of weeds quantificationally, the statistical data of the weeds and non-weeds were obtained by comparing the SAM classification image with the best classification effects to the manual classification image. The experimental results demonstrated that, when the parameters were set as 5-point smoothing, 0-order derivative and 7-degree spectral angle, the best classification result was acquired and the recognition rate of weeds, non-weeds and overall samples was 80%, 97.3% and 96.8% respectively. The method that combined the spectral imaging technology and the SAM taxonomy together took full advantage of fusion information of spectrum and image. By applying the spatial classification algorithms to establishing training sets for spectral identification, checking the similarity among spectral vectors in the pixel level, integrating the advantages of

  18. Possible Detection of Perchlorates by the Sample Analysis at Mars (SAM) Instrument: Comparison with Previous Missions

    NASA Technical Reports Server (NTRS)

    Navarro-Gonzalex, Rafael; Sutter, Brad; Archer, Doug; Ming, Doug; Eigenbrode, Jennifer; Franz, Heather; Glavin, Daniel; McAdam, Amy; Stern, Jennifer; McKay, Christopher; Coll, Patrice; Cabane, Michel; Mahaffy, Paul; Conrad, Pamela; Martin-Torres, Francisco; Zorzano-Mier, Maria; Grotzinger, John

    2013-01-01

    The first chemical analysis of soluble salts in the soil was carried out by the Phoenix Lander in the Martian Arctic [1]. Surprisingly, chlorine was present as magnesium or calcium perchlorate at 0.4 to 0.6 percent. Additional support for the identification of perchlorate came from the evolved gas analysis which detected the release of molecular oxygen at 350-550C [1]. When Mars-like soils from the Atacama Desert were spiked with magnesium perchlorate (1 percent) and heated using the Viking GC-MS protocol, nearly all the organics were combusted but a small amount was chlorinated, forming chloromethane and dichloromethane [2]. These chlorohydrocarbons were detected by the Viking GC-MS experiments when the Martian soil was analyzed but they were considered to be terrestrial contaminants [3]. Reinterpretation of the Viking results suggests <0.1 percent perchlorate and ppm levels of organic carbon at landing site 1 and 2 [2]. The suggestion of perchlorate in the Viking sites [2] has been challenged on the grounds that the detected compounds (CH3Cl and CH2Cl2) were carried from Earth [4]. Recently the Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory (MSL) ran four samples from an aeolian bedform named Rocknest. The samples analyzed were portioned from the fifth scoop at this location. The samples were heated to 835C at 35C/min with a He flow. The SAM QMS detected a major oxygen release (300-500C) [5], coupled with the release of chlorinated hydrocarbons (chloromethane, dichloromethane, trichloromethane, and chloromethylpropene) detected both by SAM QMS and GC-MS derived from known Earth organic contaminants in the instrument [6]. Calcium perchlorate appears to be the best candidate for evolved O2 in the Rocknest samples at this time but other Cl species (e.g., chlorates) are possible and must be evaluated. The potential detection of perchlorates in Rocknest material adds weight to the argument that both Viking Landers measured signatures of

  19. P-SAMS: a web site for plant artificial microRNA and synthetic trans-acting small interfering RNA design

    PubMed Central

    Fahlgren, Noah; Hill, Steven T.; Carrington, James C.; Carbonell, Alberto

    2016-01-01

    Summary: The Plant Small RNA Maker Site (P-SAMS) is a web tool for the simple and automated design of artificial miRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs) for efficient and specific targeted gene silencing in plants. P-SAMS includes two applications, P-SAMS amiRNA Designer and P-SAMS syn-tasiRNA Designer. The navigation through both applications is wizard-assisted, and the job runtime is relatively short. Both applications output the sequence of designed small RNA(s), and the sequence of the two oligonucleotides required for cloning into ‘B/c’ compatible vectors. Availability and implementation: The P-SAMS website is available at http://p-sams.carringtonlab.org. Contact: acarbonell@ibmcp.upv.es or nfahlgren@danforthcenter.org PMID:26382195

  20. Mitochondrial Sorting and Assembly Machinery Subunit Sam37 in Candida albicans: Insight into the Roles of Mitochondria in Fitness, Cell Wall Integrity, and Virulence

    PubMed Central

    Qu, Yue; Jelicic, Branka; Pettolino, Filomena; Perry, Andrew; Lo, Tricia L.; Hewitt, Victoria L.; Bantun, Farkad; Beilharz, Traude H.; Peleg, Anton Y.; Lithgow, Trevor; Djordjevic, Julianne T.

    2012-01-01

    Recent studies indicate that mitochondrial functions impinge on cell wall integrity, drug tolerance, and virulence of human fungal pathogens. However, the mechanistic aspects of these processes are poorly understood. We focused on the mitochondrial outer membrane SAM (Sorting and Assembly Machinery) complex subunit Sam37 in Candida albicans. Inactivation of SAM37 in C. albicans leads to a large reduction in fitness, a phenotype not conserved with the model yeast Saccharomyces cerevisiae. Our data indicate that slow growth of the sam37ΔΔ mutant results from mitochondrial DNA loss, a new function for Sam37 in C. albicans, and from reduced activity of the essential SAM complex subunit Sam35. The sam37ΔΔ mutant was hypersensitive to drugs that target the cell wall and displayed altered cell wall structure, supporting a role for Sam37 in cell wall integrity in C. albicans. The sensitivity of the mutant to membrane-targeting antifungals was not significantly altered. The sam37ΔΔ mutant was avirulent in the mouse model, and bioinformatics showed that the fungal Sam37 proteins are distant from their animal counterparts and could thus represent potential drug targets. Our study provides the first direct evidence for a link between mitochondrial function and cell wall integrity in C. albicans and is further relevant for understanding mitochondrial function in fitness, antifungal drug tolerance, and virulence of this major pathogen. Beyond the relevance to fungal pathogenesis, this work also provides new insight into the mitochondrial and cellular roles of the SAM complex in fungi. PMID:22286093

  1. Study of the resistance of SAMs on aluminium to acidic and basic solutions using dynamic contact angle measurement.

    PubMed

    Liakos, Ioannis L; Newman, Roger C; McAlpine, Eoghan; Alexander, Morgan R

    2007-01-30

    We report the development of a method to determine the aqueous stability of self-assembled monolayers (SAMs) using the Wilhelmy plate dynamic contact angle (DCA) experiment. The DCA is measured in solutions over a range of pH values for alkyl carboxylic and alkyl phosphonic acid SAMs formed on magnetron-sputtered aluminum. The change in DCA on repeated immersion is used as a measure of the degradation of the SAMs by hydrolytic attack. The short and intermediate chain length alkyl acids are not stable in water of neutral pH, whereas molecules with the longest alkyl chains show considerably greater stability in neutral and both high and low pH solutions. The packing density inferred from the DCA and the contact angle hysteresis suggests the C18CO2H monolayer to be slightly less well packed than that of the C18P(=O)(OH)2; this is consistent with related friction force microscopy and infrared reflection absorption spectroscopy findings published elsewhere (Foster, T. T.; Alexander, M. R.; Leggett, G. J.; McAlpine, E. Langmuir 2006, 22, 9254-9259). The resistance of the SAMs to acid and alkaline environments is discussed in the context of aluminum oxide solubility, SAM packing density, and the resistance of the interfacial phosphate and carboxylate functionalities to different aqueous conditions.

  2. Structural insights into recognition and repair of UV-DNA damage by Spore Photoproduct Lyase, a radical SAM enzyme

    PubMed Central

    Benjdia, Alhosna; Heil, Korbinian; Barends, Thomas R. M.; Carell, Thomas; Schlichting, Ilme

    2012-01-01

    Bacterial spores possess an enormous resistance to ultraviolet (UV) radiation. This is largely due to a unique DNA repair enzyme, Spore Photoproduct Lyase (SP lyase) that repairs a specific UV-induced DNA lesion, the spore photoproduct (SP), through an unprecedented radical-based mechanism. Unlike DNA photolyases, SP lyase belongs to the emerging superfamily of radical S-adenosyl-l-methionine (SAM) enzymes and uses a [4Fe–4S]1+ cluster and SAM to initiate the repair reaction. We report here the first crystal structure of this enigmatic enzyme in complex with its [4Fe–4S] cluster and its SAM cofactor, in the absence and presence of a DNA lesion, the dinucleoside SP. The high resolution structures provide fundamental insights into the active site, the DNA lesion recognition and binding which involve a β-hairpin structure. We show that SAM and a conserved cysteine residue are perfectly positioned in the active site for hydrogen atom abstraction from the dihydrothymine residue of the lesion and donation to the α-thyminyl radical moiety, respectively. Based on structural and biochemical characterizations of mutant proteins, we substantiate the role of this cysteine in the enzymatic mechanism. Our structure reveals how SP lyase combines specific features of radical SAM and DNA repair enzymes to enable a complex radical-based repair reaction to take place. PMID:22761404

  3. Evolved Gas Analyses of the Murray Formation in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars (SAM) Instrument

    NASA Technical Reports Server (NTRS)

    Sutter, B.; McAdam, A. C.; Rampe, E. B.; Thompson, L. M.; Ming, D. W.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Stern, J. C.; Eigenbrode, J. L.; Archer, P. D.

    2017-01-01

    The Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory rover has analyzed 13 samples from Gale Crater. All SAM-evolved gas analyses have yielded a multitude of volatiles (e.g., H2O, SO2, H2S, CO2, CO, NO, O2, HCl) [1- 6]. The objectives of this work are to 1) Characterize recent evolved SO2, CO2, O2, and NO gas traces of the Murray formation mudstone, 2) Constrain sediment mineralogy/composition based on SAM evolved gas analysis (SAM-EGA), and 3) Discuss the implications of these results relative to understanding the geological history of Gale Crater.

  4. The nuclear protein Sam68 is redistributed to the cytoplasm and is involved in PI3K/Akt activation during EV71 infection.

    PubMed

    Zhang, Hua; Cong, Haolong; Song, Lei; Tien, Po

    2014-02-13

    Nuclear proteins can be triggered to be redistributed to the cytoplasm to assist with EV71 virus replication. This process is frequently involved in cellular signal transduction upon virus infection. In this study, we have demonstrated that a new nuclear protein, 68-kDa Src-associated in mitosis protein (Sam68), was translocated to the cytoplasm and was co-localized with EV71 during virus infection. Confocal microscopy and subcellular fractionation assay confirmed that virus 3C protease triggered the redistribution of Sam68 to the cytoplasm. Knockdown of Sam68 expression using ShRNA significantly inhibited virus replication, suggesting that Sam68 may be a host factor involved in EV71 life cycle. In addition, EV71-induced Akt phosphorylation involved a PI3K-dependent mechanism. Sam68 is known to be an upstream regulator of PI3K and our immunoprecipitation studies confirmed that Sam68 interacted directly with the p85 regulatory subunit of PI3K and mediated PI3K/Akt activation during EV71 infection. On the contrary, silencing of Sam68 dramatically abrogated Akt phosphorylation. These data, plus the fact that Sam68 is known to be a signaling adaptor protein, indicated that Sam68 is a signal molecule with a functional role in the PI3K/Akt signal pathway during EV71 infection.

  5. Two Fe-S clusters catalyse sulfur insertion by Radical-SAM methylthiotransferases

    PubMed Central

    Forouhar, Farhad; Arragain, Simon; Atta, Mohamed; Gambarelli, Serge; Mouesca, Jean-Marie; Hussain, Munif; Xiao, Rong; Kieffer-Jaquinod, Sylvie; Seetharaman, Jayaraman; Acton, Thomas B.; Montelione, Gaetano T.

    2014-01-01

    How living organisms create carbon-sulfur bonds during biosynthesis of critical sulphur-containing compounds is still poorly understood. The methylthiotransferases MiaB and RimO catalyze sulfur insertion into tRNAs and ribosomal protein S12, respectively. Both belong to a sub-group of Radical-SAM enzymes that bear two [4Fe-4S] clusters. One cluster binds S-Adenosylmethionine and generates an Ado• radical via a well- established mechanism. However, the precise role of the second cluster is unclear. For some sulfur-inserting Radical-SAM enzymes, this cluster has been proposed to act as a sacrificial source of sulfur for the reaction. In this paper, we report parallel enzymological, spectroscopic and crystallographic investigations of RimO and MiaB, which provide the first evidence that these enzymes are true catalysts and support a new sulfation mechanism involving activation of an exogenous sulfur co-substrate at an exchangeable coordination site on the second cluster, which remains intact during the reaction. PMID:23542644

  6. Unliganded EphA3 dimerization promoted by the SAM domain

    NASA Astrophysics Data System (ADS)

    Hristova, Kalina; Singh, Deo; King, Christopher; Ahmed, Fozia; Pasquale, Elena

    The EphA3 receptor tyrosine kinase regulates morphogenesis during development, and is overexpressed and mutated in a variety of cancers. EphA3 activation is believed to follow a ``seeding mechanism'' model, in which ligand binding to the monomeric receptor acts as a trigger for signal-productive receptor clustering. We use a novel approach to study EphA3 lateral interactions on the surface of live cells, and we demonstrate that EphA3 forms dimers in the absence of ligand binding. We further show that these dimers are stabilized by interactions involving the EphA3 SAM domain. The discovery of unliganded EphA3 dimers challenges the current understanding of the chain of EphA3 activation events, and suggests that EphA3 may follow the ``pre-formed dimer'' model of activation known to be relevant for other receptor tyrosine kinases. This work also establishes a new role for the SAM domain in promoting Eph receptor lateral interactions and signaling on the cell surface.

  7. αβ'-NAC cooperates with Sam37 to mediate early stages of mitochondrial protein import.

    PubMed

    Ponce-Rojas, José Carlos; Avendaño-Monsalve, Maria Clara; Yañez-Falcón, Armando Roberto; Jaimes-Miranda, Fabiola; Garay, Erika; Torres-Quiroz, Francisco; DeLuna, Alexander; Funes, Soledad

    2017-03-01

    The mitochondrial proteome is mostly composed of nuclear-encoded proteins. Such polypeptides are synthesized with signals that guide their intracellular transport to the surface of the organelle and later within the different mitochondrial subcompartments until they reach their functional destination. It has been suggested that the nascent-polypeptide associated complex (NAC) - a cytosolic chaperone that recognizes nascent chains on translationally active ribosomes - has a role in the import of nuclear-encoded mitochondrial proteins. However, the molecular mechanisms that regulate the NAC-mediated cotranslational import are still not clear. Here, we show that a particular NAC heterodimer formed by subunits α and β' in Saccharomyces cerevisiae is specifically involved in the process of mitochondrial import and functionally cooperates with Sam37, an outer membrane protein subunit of the sorting and assembly machinery complex. Mutants in both components display growth defects, incorrectly accumulate precursor forms of mitochondrial proteins in the cytosol, and have an altered mitochondrial protein content. We propose that αβ'-NAC and Sam37 are members of the system that recognizes mitochondrial proteins at early stages of their synthesis, escorting them to the import machinery of mitochondria.

  8. Superhydrophobic SAM Modified Electrodes for Enhanced Current Limiting Properties in Intrinsic Conducting Polymer Surge Protection Devices.

    PubMed

    Jabarullah, Noor H; Verrelli, Emanuele; Mauldin, Clayton; Navarro, Luis A; Golden, Josh H; Madianos, Leonidas M; Kemp, Neil T

    2015-06-09

    Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au-polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effect.

  9. SAM 2 measurements of the polar stratospheric aerosol. Volume 9: October 1982-April 1983

    SciTech Connect

    Mcmaster, L.R.; Powell, K.A.

    1991-02-01

    The Stratospheric Aerosol Measurement (SAM) II sensor aboard Nimbus 7 is providing 1.0 micron extinction measurements of Antarctic and Arctic stratospheric aerosols with a vertical resolution of 1 km. Representative examples and weekly averages including corresponding temperature profiles provided by NOAA for the time and place of each SAM II measurement are presented. Contours of aerosol extinction as a function of altitude and longitude or time are plotted, and aerosol optical depths are calculated for each week. Typical values of aerosol extinction and stratospheric optical depth in the Arctic are unusually large due to the presence of material from the El Chichon volcano eruption in the Spring of 1982. For example, the optical depth peaked at 0.068, more than 50 times background values. Typical values of aerosol extinction and stratospheric optical depth in the Antarctic varied considerably during this period due to the transport and arrival of the material from the El Chichon eruption. For example, the stratospheric optical depth varied from 0.002 in October 1982, to 0.021 in January 1983. Polar stratospheric clouds were observed during the Arctic winter, as expected. A representative sample is provided of the ninth 6-month period of data to be used in atmospheric and climatic studies.

  10. Structure of the chromosomal insertion site for pSAM2: functional analysis in Escherichia coli.

    PubMed

    Raynal, A; Tuphile, K; Gerbaud, C; Luther, T; Guérineau, M; Pernodet, J L

    1998-04-01

    The element pSAM2 from Streptomyces ambofaciens integrates into the chromosome through site-specific recombination between the element (attP) and the chromosomal (attB) sites. These regions share an identity segment of 58bp extending from the anti-codon loop through the 3' end of a tRNA(Pro) gene. To facilitate the study of the attB site, the int and xis genes, expressed from an inducible promoter, and attP from pSAM2 were cloned on plasmids in Escherichia coil. Compatible plasmids carrying the different attB regions to be tested were introduced in these E. coli strains. Under these conditions, Int alone could promote site-specific integration; Int and Xis were both required for site-specific excision. This experimental system was used to study the sequences required in attB for efficient site-specific recombination. A 26 bp sequence, centred on the anti-codon loop region and not completely included in the identity segment, retained all the functionality of attB; shorter sequences allowed integration with lower efficiencies. By comparing the 26-bp-long attB with attP, according to the Lambda model, we propose that B and B', C and C' core-type Int binding sites consist of 9 bp imperfect inverted repeats separated by a 5 bp overlap region.

  11. Directed immobilization of reduced antibody fragments onto a novel SAM on gold for myoglobin impedance immunosensing.

    PubMed

    Billah, Md Morsaline; Hodges, Christopher S; Hays, Henry C W; Millner, P A

    2010-11-01

    The successful construction of an immunosensor depends on having an effective procedure for immobilising the bio-recognition element to the transducer surface. In the present study, an amino-terminated 4-aminothiophenol (ATP) self-assembled monolayer (SAM) was modified with heterobifunctional crosslinker sulfosuccinimidyl 4-[N-maleimidomethyl] cyclohexane-1-carboxylate to couple reduced anti-myoglobin half-antibody fragments. The disulphide groups present in the hinge region of IgG molecules were selectively cleaved by 2-mercaptoethylamine to produce reduced half-antibody fragments with free sulphydryl groups. The maleimide terminated 4-ATP SAM modified surface was coupled to these reduced antibody fragments to produce highly oriented immobilization of the half-antibody via its Fc domain and to allow free access to the Fv bindings sites. This represents an improvement by comparison with biotin/avidin mediated IgG attachment which is essentially randomly oriented. Functional immunosensors were able to detect myoglobin in both phosphate buffered saline and whole serum over the range of concentrations from 10(-13)M to 10(-6)M, and order of magnitude better than avidin/biotin linked immunosensors. In addition, atomic force microscopy (AFM) was carried out to elucidate the nanotopology of the immunosensor surface at different stages of fabrication; the images demonstrate that half antibodies bind as described and show structural changes on subsequent antigen binding.

  12. Wet Chemistry on SAM: How it Helps to Detect Organics on Mars

    NASA Astrophysics Data System (ADS)

    Buch, Arnaud; Freissinet, Caroline; Szopa, Cyril; Glavin, Danny; Coll, Patrice; Cabane, Michel; Eigenbrode, Jen; Navarro-Gonzalez, Rafael; Stern, Jen; Coscia, David; Teinturier, Samuel; Dworkin, Jason; Mahaffy, Paul; MSL Science Team

    2013-04-01

    For the first time in the history of space exploration, a mission of interest to astrobiology could be able to analyze refractory organic compounds in the soil of Mars with wet chemistry. This analytical technique modifies organic components in such a way that improves their detection, either by releasing the compounds from sample matrices, or by changing the chemical structure to be amenable to analytical conditions. The latter effect is particularly important when polar compounds are present. Sample Analysis at Mars (SAM), on the Curiosity rover of the Mars Science Laboratory mission, onboards two wet chemistry experiments: derivatization [1-2] and thermochemolysis [3-4]. Here we report on the nature of the MTBSTFA derivatization experiment in SAM, the detection of MTBSTFA in the first SAM analyzes, and the implications of this detection. Chemical derivatization of polar molecular compounds is achieved by the MTBSTFA (N-Methyl-N-tert-butyldimethylsilyltrifluoroacetamide) / DMF (Dimethylformamide) silylation reaction in order to transform refractory polar compounds into a more volatile form that can be analyzed and detected by GCMS. The first samples of Martian soil (Rocknest, Gale crater) have been analyzed by evolved gas analysis (EGA) and via GC using thermal conductivity (TCD) and MS detection. The samples have been heated up to approximately 840°C with a heating rate of 35°C/min under He flow. The evolved gas was analyzed directly by the QMS in EGA mode. For GC analyses, the majority of the gas released was trapped on a hydrocarbon trap (silica beads, Tenax TA, Carbosieve G) over a specific temperature range. Trapped volatiles were then released by heating the trap to ~300 °C and sent to the GC under He flow. The first results obtained when running an analysis with an empty cup (no solid sample) showed the presence of MTBSTFA in the system. MTBSTFA was first detected in the EGA-QMS analysis blank then by GC-TCD-QMS analysis. This means that MTBSTFA is part

  13. Toward a prediction of the redox properties of electroactive SAMs: a free energy calculation by molecular simulation.

    PubMed

    Filippini, Gaëlle; Goujon, Florent; Bonal, Christine; Malfreyt, Patrice

    2010-10-14

    We report free energy calculations of FcC(6)S-/C(4)S-Au and FcC(6)S-/C(12)S-Au binary self-assembled monolayers (SAMs) formed by one ferrocenylhexanethiolate chain and alkylthiolate chains. We demonstrate that the free energy perturbation methods are able to reproduce the positive shift of the redox potential when the coadsorbed butanethiolate C(4)S chains are replaced by dodecanethiolate C(12)S chains. The different contributions to the Ewald summation involved in the perturbation process are thoroughly described. We complete the study by a microscopic description of the binary SAMs before and after oxidation. The molecular dynamics (MD) simulations evidence that the formation of the ion-pair between the ferricinium and a single perchlorate anion of the supporting electrolyte is more favored in FcC(6)S-/C(12)S-Au SAM.

  14. SAMS Acceleration Measurements on Mir from May 1997 to June 1998 (NASA Increments 5, 6, and 7)

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard

    1999-01-01

    During NASA Increments 5, 6, and 7 (May 1997 to June 1998), about eight gigabytes of acceleration data were collected by the Space Acceleration Measurement System (SAMS) onboard the Russian Space Station Mir. The data were recorded on twenty-seven optical disks which were returned to Earth on Orbiter missions STS-86, STS-89, and STS-91. During these increments, SAMS data were collected in the Priroda module to support various microgravity experiments. This report points out some of the salient features of the microgravity acceleration environment to which the experiments were exposed. This report presents an overview of the SAMS acceleration measurements recorded by 10 Hz and 100 Hz sensor heads. The analyses included herein complement those presented in previous Mir increment summary reports prepared by the Principal Investigator Microgravity Services project.

  15. Mode and origin of replication of pSAM2, a conjugative integrating element of Streptomyces ambofaciens.

    PubMed

    Hagège, J; Pernodet, J L; Friedmann, A; Guérineau, M

    1993-11-01

    pSAM2 is an 11 kb integrating element from Streptomyces ambofaciens that is capable of replication. It generates single-stranded DNA during replication, and is therefore the first Streptomyces integrating element to be described that may belong to the family of elements, called the ssDNA elements, that replicate by a rolling-circle mechanism. The direction of replication has been identified. The plus origin (ori) of replication and minus origin (M-O) have been located. Streptomyces lividans harbouring replicating pSAM2 also contain numerous small covalently closed circular DNA molecules (scm) derived from pSAM2. These scm contain ori and extend on both sides of the putative nick site. Sequences at the junction points of these scm are heterogeneous but short direct repeats were always found in the vicinity of these junctions.

  16. Data handling with SAM and art at the NOvA experiment

    SciTech Connect

    Aurisano, A.; Backhouse, C.; Davies, G. S.; Illingworth, R.; Mayer, N.; Mengel, M.; Norman, A.; Rocco, D.; Zirnstein, J.

    2015-12-23

    During operations, NOvA produces between 5,000 and 7,000 raw files per day with peaks in excess of 12,000. These files must be processed in several stages to produce fully calibrated and reconstructed analysis files. In addition, many simulated neutrino interactions must be produced and processed through the same stages as data. To accommodate the large volume of data and Monte Carlo, production must be possible both on the Fermilab grid and on off-site farms, such as the ones accessible through the Open Science Grid. To handle the challenge of cataloging these files and to facilitate their off-line processing, we have adopted the SAM system developed at Fermilab. SAM indexes files according to metadata, keeps track of each file's physical locations, provides dataset management facilities, and facilitates data transfer to off-site grids. To integrate SAM with Fermilab's art software framework and the NOvA production workflow, we have developed methods to embed metadata into our configuration files, art files, and standalone ROOT files. A module in the art framework propagates the embedded information from configuration files into art files, and from input art files to output art files, allowing us to maintain a complete processing history within our files. Embedding metadata in configuration files also allows configuration files indexed in SAM to be used as inputs to Monte Carlo production jobs. Further, SAM keeps track of the input files used to create each output file. Parentage information enables the construction of self-draining datasets which have become the primary production paradigm used at NOvA. In this study we will present an overview of SAM at NOvA and how it has transformed the file production framework used by the experiment.

  17. COATING METHOD

    DOEpatents

    Townsend, R.G.

    1959-08-25

    A method is described for protectively coating beryllium metal by etching the metal in an acid bath, immersing the etched beryllium in a solution of sodium zincate for a brief period of time, immersing the beryllium in concentrated nitric acid, immersing the beryhlium in a second solution of sodium zincate, electroplating a thin layer of copper over the beryllium, and finally electroplating a layer of chromium over the copper layer.

  18. Insight into Sam Francis' painting techniques through the analytical study of twenty-eight artworks made between 1946 and 1992

    NASA Astrophysics Data System (ADS)

    Defeyt, Catherine; Mazurek, Joy; Zebala, Aneta; Burchett-Lere, Debra

    2016-11-01

    The present paper proposes an overview of the painting materials experimented with over the years by Sam Francis, leading figure of the post-World War II American painting, through the analytical study of an extended number of paint samples supplied by the Sam Francis Foundation. In total, 279 samples taken from twenty-eight artworks made between 1946 and 1992, were analyzed by Raman, FTIR and Py-GC/MS techniques. The obtained results revealed the Francis' preference in terms of pigments, i.e., phthalocyanine blues and greens, and outlined unconventional combination of binder media.

  19. Hierarchical Storage Management at the NASA Center for Computational Sciences: From UniTree to SAM-QFS

    NASA Technical Reports Server (NTRS)

    Salmon, Ellen; Tarshish, Adina; Palm, Nancy; Patel, Sanjay; Saletta, Marty; Vanderlan, Ed; Rouch, Mike; Burns, Lisa; Duffy, Daniel; Caine, Robert

    2004-01-01

    This paper presents the data management issues associated with a large center like the NCCS and how these issues are addressed. More specifically, the focus of this paper is on the recent transition from a legacy UniTree (Legato) system to a SAM-QFS (Sun) system. Therefore, this paper will describe the motivations, from both a hardware and software perspective, for migrating from one system to another. Coupled with the migration from UniTree into SAM-QFS, the complete mass storage environment was upgraded to provide high availability, redundancy, and enhanced performance. This paper will describe the resulting solution and lessons learned throughout the migration process.

  20. Inversion of solar extinction data from the Apollo-Soyuz Test Project Stratospheric Aerosol Measurement (ASTP/SAM) experiment

    NASA Technical Reports Server (NTRS)

    Pepin, T. J.

    1977-01-01

    The inversion methods are reported that have been used to determine the vertical profile of the extinction coefficient due to the stratospheric aerosols from data measured during the ASTP/SAM solar occultation experiment. Inversion methods include the onion skin peel technique and methods of solving the Fredholm equation for the problem subject to smoothing constraints. The latter of these approaches involves a double inversion scheme. Comparisons are made between the inverted results from the SAM experiment and near simultaneous measurements made by lidar and balloon born dustsonde. The results are used to demonstrate the assumptions required to perform the inversions for aerosols.

  1. COOH-terminated SAMs on Gold Fabricated from an Azobenzene Derivative with a 1,2-dithiolane Headgroup

    SciTech Connect

    Siemeling, U.; Rittinghaus, S; Weidner, T; Brison, J; Castner, D

    2010-01-01

    Well-defined and homogeneous, contamination-free self-assembled monolayers (SAMs) were fabricated by the chemisorption of lip-NH-p-C{sub 6}H{sub 4}-N {double_bond} N-p-C{sub 6}H{sub 4}-COOH (lip = {alpha}-lipoyl) onto gold. This adsorbate species is composed of a 1,2-dithiolane-based headgroup, an azobenzene-based (and hence photochromic) spacer unit and a carboxylic acid functional group. The SAM constituents are covalently attached to the substrate by the bidentate thiolate anchor groups and exhibit a strongly tilted binding configuration.

  2. MSL SAM-Like Evolved Gas Analyses of Si-rich Amorphous Materials

    NASA Technical Reports Server (NTRS)

    McAdam, Amy; Knudson, Christine; Sutter, Brad; Andrejkovicova, Slavka; Archer, P. Douglas; Franz, Heather; Eigenbrode, Jennifer; Morris, Richard; Ming, Douglas; Sun, Vivian; Wilhelm, Mary Beth; Mahaffy, Paul

    2016-01-01

    Chemical and mineralogical analyses of several samples from Murray Formation mudstones and Stimson Formation sandstones by the Mars Science Laboratory (MSL) revealed the presence of Si-rich amorphous or poorly ordered materials. It is possible to identify the presence of high-SiO2 vs. lower SiO2 amorphous materials (e.g., basaltic glasses), based on the position of the resulting wide diffraction features in XRD patterns from the Chemistry and Mineralogy (CheMin) instrument, but it is not possible to distinguish between several candidate high-SiO2 amorphous materials such as opal-A or rhyolitic glass. In the Buckskin (BS) sample from the upper Murray Formation, and the Big Sky (BY) and Greenhorn (GH) samples from the Stimson Formation, analyses by the Sample Analysis at Mars (SAM) instrument showed very broad H2O evolutions during sample heating at temperatures >450-500degC which had not been observed from previous samples. BS also had a significant broad evolution <450-500degC. We have undertaken a laboratory study targeted at understanding if the data from SAM can be used to place constraints on the nature of the amorphous phases. SAM-like evolved gas analyses have been performed on several opal and rhyolitic glass samples. Opal-A samples exhibited wide <500degC H2O evolutions, with lesser H2O evolved above 500degC. H2O evolution traces from rhyolitic glasses varied, having either two broad H2O peaks, <300degC and >500degC, or a broad peak centered around 400degC. For samples that produced two evolutions, the lower temperature peak is more intense than the higher temperature peak, a trend also exhibited by opal-A. This trend is consistent with data from BS, but does not seem consistent with data from BY and GH which evolved most of their H2O >500degC. It may be that dehydration of opal-A and/or rhyolitic glass can result in some preferential loss of lower temperature H2O, to produce traces that more closely resemble BY and GH. This is currently under investigation

  3. Thermal radiative properties: Coatings.

    NASA Technical Reports Server (NTRS)

    Touloukian, Y. S.; Dewitt, D. P.; Hernicz, R. S.

    1972-01-01

    This volume consists, for the most part, of a presentation of numerical data compiled over the years in a most comprehensive manner on coatings for all applications, in particular, thermal control. After a moderately detailed discussion of the theoretical nature of the thermal radiative properties of coatings, together with an overview of predictive procedures and recognized experimental techniques, extensive numerical data on the thermal radiative properties of pigmented, contact, and conversion coatings are presented. These data cover metallic and nonmetallic pigmented coatings, enamels, metallic and nonmetallic contact coatings, antireflection coatings, resin coatings, metallic black coatings, and anodized and oxidized conversion coatings.

  4. Evaluating the Effectiveness of Self-Administration of Medication (SAM) Schemes in the Hospital Setting: A Systematic Review of the Literature

    PubMed Central

    Richardson, Suzanna J.; Brooks, Hannah L.; Bramley, George; Coleman, Jamie J.

    2014-01-01

    Background Self-administration of medicines is believed to increase patients' understanding about their medication and to promote their independence and autonomy in the hospital setting. The effect of inpatient self-administration of medication (SAM) schemes on patients, staff and institutions is currently unclear. Objective To systematically review the literature relating to the effect of SAM schemes on the following outcomes: patient knowledge, patient compliance/medication errors, success in self-administration, patient satisfaction, staff satisfaction, staff workload, and costs. Design Keyword and text word searches of online databases were performed between January and March 2013. Included articles described and evaluated inpatient SAM schemes. Case studies and anecdotal studies were excluded. Results 43 papers were included for final analysis. Due to the heterogeneity of results and unclear findings it was not possible to perform a quantitative synthesis of results. Participation in SAM schemes often led to increased knowledge about drugs and drug regimens, but not side effects. However, the effect of SAM schemes on patient compliance/medication errors was inconclusive. Patients and staff were highly satisfied with their involvement in SAM schemes. Conclusions SAM schemes appear to provide some benefits (e.g. increased patient knowledge), but their effect on other outcomes (e.g. compliance) is unclear. Few studies of high methodological quality using validated outcome measures exist. Inconsistencies in both measuring and reporting outcomes across studies make it challenging to compare results and draw substantive conclusions about the effectiveness of SAM schemes. PMID:25463269

  5. Fabrication and tribological properties of self-assembled monolayer of n-alkyltrimethoxysilane on silicon: Effect of SAM alkyl chain length

    NASA Astrophysics Data System (ADS)

    Huo, Lixia; Du, Pengcheng; Zhou, Hui; Zhang, Kaifeng; Liu, Peng

    2017-02-01

    It is well known that the self-assembled organic molecules on a solid surface exhibit the friction-reducing performance. However, the effect of the molecular size of the self-assembled organic molecules has not been established. In the present work, self-assembled monolayers (SAMs) of n-alkyltrimethoxysilanes with different alkyl chain lengths (C6, C12, or C18) were fabricated on silicon substrate. The water contact angles of the SAMs increased from 26.8° of the hydroxylated silicon substrate to near 60° after self-assembly. The atomic force microscopy (AFM) analysis results showed that the mean roughness (Ra) of the SAMs decreased with increasing the alkyl chain length. The tribological properties of the SAMs sliding against Al2O3 ball were evaluated on an UMT-2 tribometer, and the worn surfaces of the samples were analyzed by means of Nano Scratch Tester and surface profilometry. It was found that lowest friction coefficient and smallest width of wear were achieved with the SAMs of C12 alkyl chain (C12-SAM). The superior friction reduction and wear resistance of the SAMs in comparison with the bare silicon substrate are attributed to good adhesion of the self-assembled films to the substrate, especially the C12-SAM with desirable alkyl chain length.

  6. Tools for grid deployment of CDF offline and SAM data handling systems for summer 2004 computing

    SciTech Connect

    Kreymer, A.; Baranovski, A.; Garzoglio, G.; Herber, R.; Illingworth, R.; Kennedy, R.; Loebel-Carpenter, L.; Lyon, A.; Merritt, W.; Stonjek, S.; Terekhov, I.; Trumbo, J.; Veseli, S.; White, S.; Bartsch, V.; Leslie, M.; Belforte, S.; Burgon-Lyon, M.; St. Denis, R.; Kerzel, U.; Ratnikov, F.; /Rutgers U., Piscataway /Texas Tech.

    2004-12-01

    The Fermilab CDF Run-II experiment is now providing official support for remote computing, which has provided approximately 35% of the total CDF computing capacity during the summer of 2004. We face the challenge of unreliable networks, time differences, and remote managers having little experience with this particular software. The approach we have taken has been to separate the data handling components from the main CDF offline code releases by means of shared libraries, permitting live upgrades to otherwise frozen code. We now use a special ''development lite'' release to ensure that all sites have the latest tools available. We have put substantial effort into revision control, so that essentially all active CDF sites are running exactly the same SAM code.

  7. Soil Moisture Monitoring Using GNSS-R Signals; First Experimental Results with the SAM Sensor

    NASA Astrophysics Data System (ADS)

    Egido, A.; Martin-Puig, C.; Felip, D.; Garcia, M.; Caparrini, M.; Farres, E.; Ruffini, G.

    2009-04-01

    is the most sensitive band to soil volumetric water content, i.e. soil moisture. Secondly, variations on thermal background do not contaminate GNSS-R signals as they do for other remote sensing techniques, such as radiometry. Finally, GNSS scatterometry from space has a potential higher spatial resolution than microwave radiometry, due to the highly stable carrier and code modulations of the incident signals which enables the use of Delay Doppler Mapping. However, in order to be able to obtain accurate SM estimates there are several effects that need to be taken into consideration. Some of those are mainly due to diffuse scattering effects over the soil surface, for instance effects due to surface roughness, vegetation canopy, and noise. This paper reviews the theoretical approach for SM retrieval using GNSS-R, and focuses on the description of the development of an innovative GNSS-R system for soil moisture retrieval (named SAM). The validation campaigns performed with the SAM sensor, together with the results obtained are presented in the paper, which is finalized with the conclusions achieved and the ideas for future work on GNSS-R based sensors. AKNOWLEDGEMENTS The authors would like to thank the European Space Agency for partially funding the SAM system development in the framework of the GSTP program, and Tragsatec for their collaboration in the acquisition of ground truth data and satellite imagery processing used for the SAM instrument validation. REFERENCES [1] A. Kavak, G. Xu, W.J. Vogel, GPS Multipath Fade Meassurements to Determine L-Band Ground Reflectivity Properties, University of Texas, Austin, 1998. [2] D. Masters, V. Zavorotny, S. Katzberg, W. Emery GPS Signal Scattering from Land for Moisture Content Determination IGARSS Proceedings, July 24-28, 2000.

  8. SAGE 1 and SAM 2 measurements of 1 micron aerosol extinction in the free troposphere

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Farrukh, U. O.; Wang, P. H.; Deepak, A.

    1988-01-01

    The SAGE 1 and SAM 2 satellite sensors were designed to measure, with global coverage, the 1 micron extinction produced by the stratospheric aerosol. In the absence of high altitude cloud, similar measurements may be made for the free tropospheric aerosol. Median extinction values in the Northern Hemisphere, for altitudes between 5 and 10 km, are found to be one-half to one order of magnitude greater than values at corresponding latitudes in the Southern Hemisphere. In addition, a seasonal increase by a factor of 1.5 yields 2 is observed in both hemispheres in local spring and summer. Following major volcanic eruptions, a long-lived enhancement of the aerosol extinction is observed for altitudes above 5 km.

  9. Constraining the source of chlorinated hydrocarbons detected on Mars with the SAM experiment onboard Curiosity

    NASA Astrophysics Data System (ADS)

    Belmahdi, I.; Buch, A.; Szopa, C.; Freissinet, C.; Glavin, D.; François, P.; Coll, P.; Eigenbrode, J.; Navarro-Gonzalez, A. R.; Dequaire, T.; Millan, M.; Tenturier, S.; Bonnet, J. Y.; Mahaffy, P.; Cabane, M.

    2015-10-01

    Organic molecules have been at the origin of the prebiotic chemistry that led to the emergence of life on Earth. Therefore, they are one of the key ingredients required to assess the habitability in environments of the solar system. On Mars, no endogenous organics were found until very recently (1) whereas they are expected to be present in the soil, either because they were kept safe in rocks since the early history of the planet, or because they are still brought to the Mars surface by exogenous sources. Because of their importance for astrobiology, efforts are still ongoing to search for these species in the Gale crater by the Curiosity rover, and especially the SAM experiment on its board.

  10. STM characterization of DNA immobilized via Zr ion glue onto gold thiol SAMs

    NASA Astrophysics Data System (ADS)

    Pourbeyram, S.; Shervedani, R. K.; Sabzyan, H.

    2013-10-01

    In this paper layer-by-layer (LBL) assembly of calf thymus DNA (ct-DNA) onto gold-mercaptopropionic acid self-assembled monolayer via Zr(IV) ion glue, Au-MPA-Zr(IV)-ct-DNA SAM, is monitored by scanning tunneling microscopy (STM) technique. The STM images of Au-MPA-Zr(IV) template show well-organized arrays of rod-like peaks. ct-DNA has been immobilized on the Au-MPA-Zr(IV) surface in hilly forms, implying globular structure for the immobilized ct-DNA. This immobilization strategy offers a simple and fast method to prepare the Au-MPA-Zr(IV)-ct-DNA template with promising applications for immobilization and study of the other compounds.

  11. Re-engineering SAM or Changing the Engine in the Train While it is Running

    NASA Astrophysics Data System (ADS)

    Illingworth, R.; Mengel, M.; Norman, A.

    2015-12-01

    In the last few years at Fermilab we re-architect-ed our SAM1[1] family of data catalog and file transfer tools - including major changes - while continuing to transfer over 1 Pb/month of data to multiple existing experiments and bring new experiments on board. This work was done with less than 3 FTE-years of effort, and the changes made include major ones, such as changing interprocess communication protocols, migrating database back-ends, removing and replacing major components, and supporting new file delivery methods. This paper will summarize the approaches we have used to do this, including using design patterns like the Facade, Adapter, and Command patterns, and assisting experiments one at a time with client migration. This process has allowed us to modernize our infrastructure with reasonable costs in both calendar time and developer effort, while continuing to provide the operating service to our customers with minimal interruptions.

  12. Folding of SAM-II riboswitch explored by replica-exchange molecular dynamics simulation.

    PubMed

    Xue, Xu; Yongjun, Wang; Zhihong, Li

    2015-01-21

    Riboswitches are cis-acting RNA fragments that function via a conformational transition mechanism when a specific target molecule binds to its binding pocket, representing an inviting new class of biomolecular target for the development of antibiotics. To understand the folding mechanism of SAM-II riboswitch, occurring predominantly in proteobacteria, a 100ns replica-exchange molecular dynamics simulation in explicit solvent is performed. Our results show that this RNA pseudoknot has multiple folding pathways, and various intermediate structures. The resultant riboswitch conformational transition map is well consistent with the recent fluorescence measurement, which confirms the dynamical properties of this pseudoknot. Moreover, a novel transition pathway is predicted. The global folding dynamics is mainly coupled with the helix rather than the loop region. The potential folding pathways of the riboswitch presented here should lead to a deeper understanding of the folding mechanism of the riboswitch, as well as the conformational change of RNA pseudoknot.

  13. SAGE I and SAM II measurements of 1 micron aerosol extinction in the free troposphere

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Farrukh, U. O.; Wang, P. H.; Deepak, A.

    1988-01-01

    The SAGE-I and SAM-II satellite sensors were designed to measure, with global coverage, the 1 micron extinction produced by the stratospheric aerosol. In the absence of high altitude clouds, similar measurements may be made for the free tropospheric aerosol. Median extinction values at middle and high latitudes in the Northern Hemisphere, for altitudes between 5 and 10 km, are found to be one-half to one order of magnitude greater than values at corresponding latitudes in the Southern Hemisphere. In addition, a seasonal increase by a factor of 1.5-2 was observed in both hemispheres, in 1979-80, in local spring and summer. Following major volcanic eruptions, a long-lived enhancement of the aerosol extinction is observed for altitudes above 5 km.

  14. SAGE and SAM II measurements of global stratospheric aerosol optical depth and mass loading

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Mccormick, M. P.

    1984-01-01

    Several volcanic eruptions between November 1979 and April 1981 have injected material into the stratosphere. The SAGE and SAM II satellite systems have measured, with global coverage, the 1-micron extinction produced by this material, and examples of the data product are shown in the form of global maps of stratospheric optical depth and altitude-latitude plots of zonal mean extinction. These data, and that for the volcanically quiet period in early 1979, have been used to determine the changes in the total stratospheric mass loading. Estimates have also been made of the contribution to the total aerosol mass from each eruption. It has been found that between 1979 and mid-1981, the total stratospheric aerosol mass increased from a background level of approximately 570,000 metric tons to a peak of approximately 1,300,000 metric tons.

  15. Investigating the Origin of Chlorohydrocarbons Detected by the Sample Analysis at Mars (SAM) Instrument at Rocknest

    NASA Technical Reports Server (NTRS)

    Glavin, D.; Archer, D.; Brunner, A.; Buch, A.; Cabane, M.; Coll, P.; Conrad, P.; Coscia, D.; Dworkin J.; Eigenbrode, J.; Freissinet, C.; Mahaffy, P.; Martin, M.; McKay, C.; Miller, K.; Ming, D.; Navarro-Gonzalez, R.; Steele, A.; Summons, R. E.; Sutter, B.; Szopa, C.; Teinturier, S.

    2013-01-01

    The search for organic compounds on Mars, including molecules of either abiotic or biological origin is one of the key goals of the Mars Science Laboratory (MSL) mission. Previously the Viking and Phoenix Lander missions searched for organic compounds, but did not find any definitive evidence of martian organic material in the soils. The Viking pyrolysis gas chromatography mass spectrometry (GCMS) instruments did not detect any organic compounds of martian or exogenous origin above a level of a few parts-per-billion (ppb) in the near surface regolith at either landing site [1]. Viking did detect chloromethane and dichloromethane at pmol levels (up to 40 ppb) after heating the soil samples up to 500 C (Table 1), although it was originally argued that the chlorohydrocarbons were derived from cleaning solvents used on the instrument hardware, and not from the soil samples themselves [1]. More recently, it was suggested that the chlorohydrocarbons detected by Viking may have been formed by oxidation of indigenous organic matter during pyrolysis of the soil in the presence of perchlorates [2]. Although it is unknown if the Viking soils contained perchlorates, Phoenix did reveal relatively high concentrations (0.6 wt%) of perchlorate salt in the icy regolith [3], therefore, it is possible that the chlorohydrocarbons detected by Viking were produced, at least partially, during the experiments [2,4]. The Sample Analysis at Mars (SAM) instrument suite on MSL analyzed the organic composition of the soil at Rocknest in Gale Crater using a combination of pyrolysis evolved gas analysis (EGA) and GCMS. One empty cup procedural blank followed by multiple EGA-GCMS analyses of the Rocknest soil were carried out. Here we will discuss the results from these SAM measurements at Rocknest and the steps taken to determine the source of the chlorohydrocarbons.

  16. Optimisation and Characterisation of Anti-Fouling Ternary SAM Layers for Impedance-Based Aptasensors.

    PubMed

    Miodek, Anna; Regan, Edward M; Bhalla, Nikhil; Hopkins, Neal A E; Goodchild, Sarah A; Estrela, Pedro

    2015-09-29

    An aptasensor with enhanced anti-fouling properties has been developed. As a case study, the aptasensor was designed with specificity for human thrombin. The sensing platform was developed on screen printed electrodes and is composed of a self-assembled monolayer made from a ternary mixture of 15-base thiolated DNA aptamers specific for human thrombin co-immobilised with 1,6-hexanedithiol (HDT) and further passivated with 1-mercapto-6-hexanol (MCH). HDT binds to the surface by two of its thiol groups forming alkyl chain bridges and this architecture protects from non-specific attachment of molecules to the electrode surface. Using Electrochemical Impedance Spectroscopy (EIS), the aptasensor is able to detect human thrombin as variations in charge transfer resistance (Rct) upon protein binding. After exposure to a high concentration of non-specific Bovine Serum Albumin (BSA) solution, no changes in the Rct value were observed, highlighting the bio-fouling resistance of the surface generated. In this paper, we present the optimisation and characterisation of the aptasensor based on the ternary self-assembled monolayer (SAM) layer. We show that anti-fouling properties depend on the type of gold surface used for biosensor construction, which was also confirmed by contact angle measurements. We further studied the ratio between aptamers and HDT, which can determine the specificity and selectivity of the sensing layer. We also report the influence of buffer pH and temperature used for incubation of electrodes with proteins on detection and anti-fouling properties. Finally, the stability of the aptasensor was studied by storage of modified electrodes for up to 28 days in different buffers and atmospheric conditions. Aptasensors based on ternary SAM layers are highly promising for clinical applications for detection of a range of proteins in real biological samples.

  17. Jeffries Matusita-Spectral Angle Mapper (JM-SAM) spectral matching for species level mapping at Bhitarkanika, Muthupet and Pichavaram mangroves

    NASA Astrophysics Data System (ADS)

    Padma, S.; Sanjeevi, S.

    2014-12-01

    This paper proposes a novel hyperspectral matching algorithm by integrating the stochastic Jeffries-Matusita measure (JM) and the deterministic Spectral Angle Mapper (SAM), to accurately map the species and the associated landcover types of the mangroves of east coast of India using hyperspectral satellite images. The JM-SAM algorithm signifies the combination of a qualitative distance measure (JM) and a quantitative angle measure (SAM). The spectral capabilities of both the measures are orthogonally projected using the tangent and sine functions to result in the combined algorithm. The developed JM-SAM algorithm is implemented to discriminate the mangrove species and the landcover classes of Pichavaram (Tamil Nadu), Muthupet (Tamil Nadu) and Bhitarkanika (Odisha) mangrove forests along the Eastern Indian coast using the Hyperion image dat asets that contain 242 bands. The developed algorithm is extended in a supervised framework for accurate classification of the Hyperion image. The pixel-level matching performance of the developed algorithm is assessed by the Relative Spectral Discriminatory Probability (RSDPB) and Relative Spectral Discriminatory Entropy (RSDE) measures. From the values of RSDPB and RSDE, it is inferred that hybrid JM-SAM matching measure results in improved discriminability of the mangrove species and the associated landcover types than the individual SAM and JM algorithms. This performance is reflected in the classification accuracies of species and landcover map of Pichavaram mangrove ecosystem. Thus, the JM-SAM (TAN) matching algorithm yielded an accuracy better than SAM and JM measures at an average difference of 13.49 %, 7.21 % respectively, followed by JM-SAM (SIN) at 12.06%, 5.78% respectively. Similarly, in the case of Muthupet, JM-SAM (TAN) yielded an increased accuracy than SAM and JM measures at an average difference of 12.5 %, 9.72 % respectively, followed by JM-SAM (SIN) at 8.34 %, 5.55% respectively. For Bhitarkanika, the combined

  18. Detection and Quantification of Nitrogen Compounds in the First Drilled Martian Solid Samples by the Sample Analysis at Mars (SAM) Instrument Suite on the Mars Science Laboratory (MSL)

    NASA Technical Reports Server (NTRS)

    Stern, J. C.; Navarro-Gonzales, R.; Freissinet, C.; McKay, C. P.; Archer, P. D., Jr.; Buch, A.; Brunner, A. E.; Coll, P.; Eigenbrode, J. L.; Franz, H. B.; Glavin, D. P.; McAdam, A. C.; Ming, D.; Steele, A.; Sutter, B.; Szopa, C.; Wray, J. J.; Conrad, P.; Mahaffy, P. R.

    2014-01-01

    The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected both reduced and oxidized nitrogen-bearing compounds during the pyrolysis of surface materials at Yellowknife Bay in Gale Crater. Preliminary detections of nitrogen species include NO, HCN, ClCN, CH3CN, and TFMA (trifluoro-N-methyl-acetamide). Confirmation of indigenous Martian N-bearing compounds requires quantifying N contribution from the terrestrial derivatization reagents (e.g. N-methyl-N-tertbutyldimethylsilyltrifluoroacetamide, MTBSTFA and dimethylformamide, DMF) carried for SAM's wet chemistry experiment that contribute to the SAM background. Nitrogen species detected in the SAM solid sample analyses can also be produced during laboratory pyrolysis experiments where these reagents are heated in the presence of perchlorate, a compound that has also been identified by SAM in Mars solid samples.

  19. Detection and Quantification of Nitrogen Compounds in the First Drilled Martian Solid Samples by the Sample Analysis at Mars (SAM) Instrument Suite on the Mars Science Laboratory (MSL)

    NASA Technical Reports Server (NTRS)

    Stern, Jennifer C.; Navarro-Gonzalez, Rafael; Freissinet, Caroline; McKay, Christopher P.; Archer, P. Douglas, Jr.; Buch, Arnaud; Coll, Patrice; Eigenbrode, Jennifer L.; Franz, Heather B.; Glavin, Daniel P.; Ming, Douglas W.; Steele, Andrew; Szopa, Cyril; Wray, James J.; Conrad, Pamela G.; Mahaffy, Paul R.

    2014-01-01

    The Sampl;e Analysis at Mars (sam) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected both reduced and oxidized nitrogen bearing compounds during the pyrolysis of surface materials from the three sites at Gale Crater. Preliminary detections of nitrogen species include No, HCN, ClCN, and TFMA ((trifluoro-N-methyl-acetamide), Confirmation of indigenous Martian nitrogen-bearing compounds requires quantifying N contribution from the terrestrial derivatization reagents carried for SAM's wet chemistry experiment that contribute to the SAM background. Nitrogen species detected in the SAM solid sample analyses can also be produced during laboratory pyrolysis experiments where these reagents are heated in the presence of perchlorate a compound that has also been identified by SAM in Mars solid samples.

  20. Boron (B) deprivation increases plasma homocysteine and decreases liver S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diverse effects of B deprivation suggest that B affects a biomolecule involved in a variety of biochemical reactions. An experiment was conducted to determine whether dietary B affects the liver concentration of SAM, a frequently used enzyme substrate, especially for methylation reactions that y...

  1. Response of sea surface fugacity of CO2 to the SAM shift south of Tasmania: Regional differences

    NASA Astrophysics Data System (ADS)

    Xue, Liang; Gao, Libao; Cai, Wei-Jun; Yu, Weidong; Wei, Meng

    2015-05-01

    Using observational data collected south of Tasmania during 14 austral summer cruises during 1993-2011, we examined the response of sea surface fugacity of carbon dioxide (fCO2) to the Southern Annular Mode (SAM) shift, which occurred around 2000. In the southern part of the Southern Ocean (SO) or the Polar Zone (PZ) and the Polar Frontal Zone (PFZ), fCO2 increased faster at the sea surface than in the atmosphere before the SAM shift, but not after the shift. In the northern part of the SO or the Subantarctic Zone (SAZ), however, surface fCO2 increased faster than atmospheric fCO2 both before and after the shift. The SAM shift had an important influence on the surface fCO2 trend in the PZ and PFZ but not in the SAZ, which we attribute to differences in regional oceanographic processes (upwelling versus nonupwelling). The SAM shift may have reversed the negative trend of SO CO2 uptake.

  2. Isothiourea-Mediated Organocatalytic Michael Addition-Lactonization on a Surface: Modification of SAMs on Silicon Oxide Substrates.

    PubMed

    Chisholm, Ross; Parkin, John D; Smith, Andrew D; Hähner, Georg

    2016-04-05

    Tailoring the functionality of self-assembled monolayers (SAMs) can be achieved either by depositing prefunctionalized molecules with the appropriate terminal groups or by chemical modification of an existing SAM in situ. The latter approach is particularly advantageous to allow for diversity of surface functionalization from a single SAM and if the incorporation of bulky groups is desired. In the present study an organocatalytic isothiourea-mediated Michael addition-lactonization process analogous to a previously reported study in solution is presented. An achiral isothiourea, 3,4-dihydro-2H-pyrimido[2,1-b]benzothiazole (DHPB), promotes the intermolecular Michael addition-lactonization of a trifluoromethylenone terminated SAM and a variety of arylacetic acids affording C(6)-trifluoromethyldihydropyranones tethered to the surface. X-ray photoelectron spectroscopy, atomic force microscopy, contact angle, and ellipsometry analysis were conducted to confirm the presence of the substituted dihydropyranone. A model study of this approach was also performed in solution to probe the reaction diastereoselectivity as it cannot be measured directly on the surface.

  3. Synergy of SAM and ChemCam instruments (Curiosity Rover) to Search for Organic Matter at Mars

    NASA Astrophysics Data System (ADS)

    Dequaire, T.; Coll, P.; Szopa, C.; Maurice, S.; Mangold, N.

    2014-07-01

    This work proposes to determine ChemCam capabilities to detect organic molecules in the martian rocks, by coupling LIBS and passive spectroscopy using the ChemCam testbed (IRAP) in order to select at best the samples analyzed by the SAM instrument.

  4. Carbon and Sulfur Isotopic Composition of Yellowknife Bay Sediments: Measurements by the Sample Analysis at Mars (SAM) Quadrupole Mass Spectrometer

    NASA Technical Reports Server (NTRS)

    Franz, H. B.; Mahaffy, P. R.; Stern, J. C.; Eigenbrode, J. L.; Steele, A.; Ming, D. W.; McAdam, A. C.; Freissinet, C.; Glavin, D. P.; Archer, P. D.; Brunner, A. E.; Grotzinger,J. P.; Jones, J. H.; Leshin, L. A.; Miller, K.; Morris, R. V.; Navarro-Gonzalez, R.; Niles, P. B.; Owen, T. C.; Summons, R. E.; Sutter, B.; Webster, C. R.

    2014-01-01

    Since landing at Gale Crater in Au-gust 2012, the Sample Analysis at Mars (SAM) instru-ment suite on the Mars Science Laboratory (MSL) “Curiosity” rover has analyzed solid samples from the martian regolith in three locations, beginning with a scoop of aeolian deposits from the Rocknest (RN) sand shadow. Curiosity subsequently traveled to Yellowknife Bay, where SAM analyzed samples from two separate holes drilled into the Sheepbed Mudstone, designated John Klein (JK) and Cumberland (CB). Evolved gas analysis (EGA) of all samples revealed the presence of H2O as well as O-, C- and S-bearing phas-es, in most cases at abundances below the detection limit of the CheMin instrument. In the absence of definitive mineralogical identification by CheMin, SAM EGA data can help provide clues to the mineralogy of volatile-bearing phases through examination of tem-peratures at which gases are evolved from solid sam-ples. In addition, the isotopic composition of these gas-es may be used to identify possible formation scenarios and relationships between phases. Here we report C and S isotope ratios for CO2 and SO2 evolved from the JK and CB mudstone samples as measured with SAM’s quadrupole mass spectrometer (QMS) and draw com-parisons to RN.

  5. Identification of a gene encoding the replication initiator protein of the Streptomyces integrating element, pSAM2.

    PubMed

    Hagège, J; Boccard, F; Smokvina, T; Pernodet, J L; Friedmann, A; Guérineau, M

    1994-03-01

    pSAM2 is an 11-kilobase integrating element from Streptomyces ambofaciens which was previously shown to generate single-stranded DNA during replication, indicating that it probably replicates by a rolling-circle replication (RCR) mechanism. Two separate regions are involved in its replication, one of which was shown to contain the plus origin of replication (ds origin). We report here the study of the second region. Its nucleotide sequence was determined and analysed for open reading frames (ORFs). Three putative ORFs were identified: orf183 (183 amino acids (aa)), orf50 (50 aa), and repSA (459 aa). orf183 is not necessary for replication. The function of orf50 is unknown. repSA is essential for pSAM2 replication; it could encode a protein, RepSA, presenting similarities to the replication initiator proteins (Rep) of elements that replicate by an RCR mechanism. A derivative consisting of repSA, the region containing ds origin, a Streptomyces antibiotic resistance marker, and pBR322, could replicate in Streptomyces, further demonstrating that this ORF encodes the major replication protein of pSAM2. repSA might be co-transcribed with the genes involved in integration and excision of pSAM2.

  6. Detection of Organic Constituents Including Chloromethylpropene in the Analyses of the ROCKNEST Drift by Sample Analysis at Mars (SAM)

    NASA Technical Reports Server (NTRS)

    Eigenbrode, J. L.; Glavin, D.; Coll, P.; Summons, R. E.; Mahaffy, P.; Archer, D.; Brunner, A.; Conrad, P.; Freissinet, C.; Martin, M.; McKay, C.; Hurowitz, J.; Evans, J.; Anderson, M.; Jandura, L.; Brown, K.; Logan C.; Kuhn, S.; Anderson, R.; Beegle, L.; Blakkolb, B.; Katz, I.; Limonadi, D.; Rainen, R.; Umland, J.

    2013-01-01

    key challenge in assessing the habitability of martian environments is the detection of organic matter - a requirement of all life as we know it. The Curiosity rover, which landed on August 6, 2012 in Gale Crater of Mars, includes the Sample Analysis at Mars (SAM) instrument suite capable of in situ analysis of gaseous organic components thermally evolved from sediment samples collected, sieved, and delivered by the MSL rover. On Sol 94, SAM received its first solid sample: scooped sediment from Rocknest that was sieved to <150 m particle size. Multiple 10-40 mg portions of the scoop #5 sample were delivered to SAM for analyses. Prior to their introduction, a blank (empty cup) analysis was performed. This blank served 1) to clean the analytical instrument of SAMinternal materials that accumulated in the gas processing system since integration into the rover, and 2) to characterize the background signatures of SAM. Both the blank and the Rocknest samples showed the presence of hydrocarbon components.

  7. Detection and Quantification of Nitrogen Compounds in Martian Solid Samples by the Sample Analysis at Mars (SAM) Instrument Suite

    NASA Technical Reports Server (NTRS)

    Stern, Jennifer C.; Navarro-Gonzalez, Rafael; Freissinet, Caroline; McKay, Christopher P.; Archer, Paul Douglas; Buch, Arnaud; Eigenbrode, Jennifer L.; Franz, Heather; Glavin, Daniel Patrick; Ming, Douglas W/; Steele, Andrew; Szopa, Cyril; Wray, James J.; Conrad, Pamela Gales; Mahaffay, Paul R.

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected both reduced and oxidized nitrogen-bearing compounds during the pyrolysis of surface materials from three sites at Gale Crater. Preliminary detections of nitrogen species include NO, HCN, ClCN, CH3CN, and TFMA (trifluoro-Nmethyl-acetamide). On Earth, nitrogen is a crucial bio-element, and nitrogen availability controls productivity in many environments. Nitrogen has also recently been detected in the form of CN in inclusions in the Martian meteorite Tissint, and isotopically heavy nitrogen (delta N-15 approx +100per mille) has been measured during stepped combustion experiments in several SNC meteorites. The detection of nitrogen-bearing compounds in Martian regolith would have important implications for the habitability of ancient Mars. However, confirmation of indigenous Martian nitrogen bearing compounds will require ruling out their formation from the terrestrial derivatization reagents (e.g. N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide, MTBSTFA and dimethylformamide, DMF) carried for SAM's wet chemistry experiment that contribute to the SAM background. The nitrogen species we detect in the SAM solid sample analyses can also be produced during laboratory pyrolysis experiments where these reagents are heated in the presence of perchlorate, a compound that has also been identified by SAM in Mars solid samples. However, this does not preclude a Martian origin for some of these compounds, which are present in nanomolar concentrations in SAM evolved gas analyses. Analysis of SAM data and laboratory breadboard tests are underway to determine whether nitrogen species are present at higher concentrations than can be accounted for by maximum estimates of nitrogen contribution from MTBSTFA and DMF. In addition, methods are currently being developed to use GC Column 6, (functionally similar to a commercial Q-Bond column), to separate and identify

  8. NICKEL COATED URANIUM ARTICLE

    DOEpatents

    Gray, A.G.

    1958-10-01

    Nickel coatings on uranium and various methods of obtaining such coatings are described. Specifically disclosed are such nickel or nickel alloy layers as barriers between uranium and aluminum- silicon, chromium, or copper coatings.

  9. Corrosion resistant coating

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  10. Corrosion resistant coating

    DOEpatents

    Wrobleski, D.A.; Benicewicz, B.C.; Thompson, K.G.; Bryan, C.J.

    1997-08-19

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  11. The Chemistry of Coatings.

    ERIC Educational Resources Information Center

    Griffith, James R.

    1981-01-01

    The properties of natural and synthetic polymeric "coatings" are reviewed, including examples and uses of such coatings as cellulose nitrate lacquers (for automobile paints), polyethylene, and others. (JN)

  12. Characterization of the Candida albicans Amino Acid Permease Family: Gap2 Is the Only General Amino Acid Permease and Gap4 Is an S-Adenosylmethionine (SAM) Transporter Required for SAM-Induced Morphogenesis

    PubMed Central

    Kraidlova, Lucie; Schrevens, Sanne; Tournu, Hélène; Van Zeebroeck, Griet; Sychrova, Hana

    2016-01-01

    ABSTRACT Amino acids are key sources of nitrogen for growth of Candida albicans. In order to detect and take up these amino acids from a broad range of different and changing nitrogen sources inside the host, this fungus must be able to adapt via its expression of genes for amino acid uptake and further metabolism. We analyzed six C. albicans putative general amino acid permeases based on their homology to the Saccharomyces cerevisiae Gap1 general amino acid permease. We generated single- and multiple-deletion strains and found that, based on growth assays and transcriptional or posttranscriptional regulation, Gap2 is the functional orthologue to ScGap1, with broad substrate specificity. Expression analysis showed that expression of all GAP genes is under control of the Csy1 amino acid sensor, which is different from the situation in S. cerevisiae, where the expression of ScGAP1 is not regulated by Ssy1. We show that Gap4 is the functional orthologue of ScSam3, the only S-adenosylmethionine (SAM) transporter in S. cerevisiae, and we report that Gap4 is required for SAM-induced morphogenesis. IMPORTANCE Candida albicans is a commensal organism that can thrive in many niches in its human host. The environmental conditions at these different niches differ quite a bit, and this fungus must be able to sense these changes and adapt its metabolism to them. Apart from glucose and other sugars, the uptake of amino acids is very important. This is underscored by the fact that the C. albicans genome encodes 6 orthologues of the Saccharomyces. cerevisiae general amino acid permease Gap1 and many other amino acid transporters. In this work, we characterize these six permeases and we show that C. albicans Gap2 is the functional orthologue of ScGap1 and that C. albicans Gap4 is an orthologue of ScSam3, an S-adenosylmethionine (SAM) transporter. Furthermore, we show that Gap4 is required for SAM-induced morphogenesis, an important virulence factor of C. albicans. PMID

  13. Effect of S-adenosyl-L-methionine (SAM), an allosteric activator of cystathionine-β-synthase (CBS) on colorectal cancer cell proliferation and bioenergetics in vitro

    PubMed Central

    Módis, Katalin; Coletta, Ciro; Asimakopoulou, Antonia; Szczesny, Bartosz; Chao, Celia; Papapetropoulos, Andreas; Hellmich, Mark R.; Szabo, Csaba

    2014-01-01

    Recent data show that colon cancer cells selectively overexpress cystathionine-β-synthase (CBS), which produces hydrogen sulfide (H2S), to maintain cellular bioenergetics, support tumor growth and stimulate angiogenesis and vasorelaxation in the tumor microenvironment. The purpose of the current study was to investigate the effect of the allosteric CBS activator S-adenosyl-L-methionine (SAM) on the proliferation and bioenergetics of the CBS-expressing colon cancer cell line HCT116. The non-transformed, non-tumorigenic colon epithelial cell line NCM356 was used as control. For assessment of cell proliferation, the xCELLigence system was used. Bioenergetic function was measured by Extracellular Flux Analysis. Experiments using human recombinant CBS or HCT116 homogenates complemented the cell-based studies. SAM markedly enhanced CBS-mediated H2S production in vitro, especially when a combination of cysteine and homocysteine was used as substrates. Addition of SAM (0.1 – 3 mM) to HCT116 cells induced a concentration-dependent increase H2S production. SAM exerted time-and concentration-dependent modulatory effects on cell proliferation. At 0.1–1 mM SAM increased HCT116 proliferation between 0–12 h, while the highest SAM concentration (3 mM) inhibited proliferation. Over a longer time period (12–24 h), only the lowest concentration of SAM used (0.1 mM) stimulated cell proliferation; higher SAM concentrations produced a concentration-dependent inhibition. The short-term stimulatory effects of SAM were attenuated by the CBS inhibitor aminooxyacetic acid (AOAA) or by stable silencing of CBS. In contrast, the inhibitory effects of SAM on cell proliferation was unaffected by CBS inhibition or CBS silencing. In contrast to HCT116 cells, the lower rate of proliferation of the low-CBS expressor NCM356 cells was unaffected by SAM. Short-term (1h) exposure of HCT116 cells to SAM induced a concentration-dependent increase in oxygen consumption and bioenergetic function at

  14. Sam68/KHDRBS1-dependent NF-κB activation confers radioprotection to the colon epithelium in γ-irradiated mice

    PubMed Central

    Fu, Kai; Sun, Xin; Wier, Eric M; Hodgson, Andrea; Hobbs, Ryan P; Wan, Fengyi

    2016-01-01

    Previously we reported that Src-associated-substrate-during-mitosis-of-68kDa (Sam68/KHDRBS1) is pivotal for DNA damage-stimulated NF-κB transactivation of anti-apoptotic genes (Fu et al., 2016). Here we show that Sam68 is critical for genotoxic stress-induced NF-κB activation in the γ-irradiated colon and animal and that Sam68-dependent NF-κB activation provides radioprotection to colon epithelium in vivo. Sam68 deletion diminishes γ-irradiation-triggered PAR synthesis and NF-κB activation in colon epithelial cells (CECs), thus hampering the expression of anti-apoptotic molecules in situ and facilitating CECs to undergo apoptosis in mice post whole-body γ-irradiation (WBIR). Sam68 knockout mice suffer more severe damage in the colon and succumb more rapidly from acute radiotoxicity than the control mice following WBIR. Our results underscore the critical role of Sam68 in orchestrating genotoxic stress-initiated NF-κB activation signaling in the colon tissue and whole animal and reveal the pathophysiological relevance of Sam68-dependent NF-κB activation in colonic cell survival and recovery from extrinsic DNA damage. DOI: http://dx.doi.org/10.7554/eLife.21957.001 PMID:27996939

  15. KorSA from the Streptomyces Integrative Element pSAM2 Is a Central Transcriptional Repressor: Target Genes and Binding Sites

    PubMed Central

    Sezonov, Guennadi; Possoz, Christophe; Friedmann, Annick; Pernodet, Jean-Luc; Guérineau, Michel

    2000-01-01

    pSAM2, a 10.9-kb mobile integrative genetic element from Streptomyces ambofaciens, possesses, as do a majority of Streptomyces conjugative plasmids, a kil-kor system associated with its transfer. The kor function of pSAM2 was attributed to the korSA gene, but its direct role remained unclear. The present study was focused on the determination of the KorSA targets. It was shown that KorSA acts as a transcriptional repressor by binding to a conserved 17-nucleotide sequence found upstream of only two genes: its own gene, korSA, and pra, a gene positively controlling pSAM2 replication, integration, and excision. A unique feature of KorSA, compared to Kor proteins from other Streptomyces conjugative plasmids, is that it does not directly regulate pSAM2 transfer. KorSA does not bind to the pSAM2 genes coding for transfer and intramycelial spreading. Through the repression of pra, KorSA is able to negatively regulate pSAM2 functions activated by Pra and, consequently, to maintain pSAM2 integrated in the chromosome. PMID:10671443

  16. KorSA from the Streptomyces integrative element pSAM2 is a central transcriptional repressor: target genes and binding sites.

    PubMed

    Sezonov, G; Possoz, C; Friedmann, A; Pernodet, J L; Guérineau, M

    2000-03-01

    pSAM2, a 10.9-kb mobile integrative genetic element from Streptomyces ambofaciens, possesses, as do a majority of Streptomyces conjugative plasmids, a kil-kor system associated with its transfer. The kor function of pSAM2 was attributed to the korSA gene, but its direct role remained unclear. The present study was focused on the determination of the KorSA targets. It was shown that KorSA acts as a transcriptional repressor by binding to a conserved 17-nucleotide sequence found upstream of only two genes: its own gene, korSA, and pra, a gene positively controlling pSAM2 replication, integration, and excision. A unique feature of KorSA, compared to Kor proteins from other Streptomyces conjugative plasmids, is that it does not directly regulate pSAM2 transfer. KorSA does not bind to the pSAM2 genes coding for transfer and intramycelial spreading. Through the repression of pra, KorSA is able to negatively regulate pSAM2 functions activated by Pra and, consequently, to maintain pSAM2 integrated in the chromosome.

  17. An S-adenosyl Methionine Synthetase (SAMS) Gene from Andropogon virginicus L. Confers Aluminum Stress Tolerance and Facilitates Epigenetic Gene Regulation in Arabidopsis thaliana

    PubMed Central

    Ezaki, Bunichi; Higashi, Aiko; Nanba, Norie; Nishiuchi, Takumi

    2016-01-01

    Candidate clones which conferred Al tolerance to yeast transformants (TFs) were obtained from a cDNA library derived from a highly Al-tolerant poaceae, Andropogon virginicus L. One such clone, AL3A-4, encoded an S-adenosyl methionine synthetase (SAMS) gene. A full-length cDNA was obtained by 5′-RACE, designated AvSAMS1, and introduced into Arabidopsis thaliana to investigate its biological functions under Al stress. Two TF plant lines both showed higher tolerance than the Col-0 ecotype (non-TF) not only for Al stress, but also for Cu, Pb, Zn and diamide stresses, suggesting the AvSAMS1 was a multiple tolerance gene. More than 40 of A. thaliana Al response-genes (Al induced genes and Al repressed genes) were selected from microarray results and then used for investigations of DNA or histone methylation status under Al stress in Col-0 and the AvSAMS1 TF line. The results indicated that Al stress caused alterations of methylation status in both DNA and histone H3 (H3K4me3 and H3K9me3) and that these alterations were different between the AvSAMS1 TF and Col-0, suggesting the differences were AvSAMS1-gene dependent. These results suggested the existence of AvSAMS1-related epigenetic gene-regulation under Al stress. PMID:27877178

  18. Electrocurtain coating process for coating solar mirrors

    DOEpatents

    Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

    2013-10-15

    An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

  19. Space Acceleration Measurement System (SAMS)/Orbital Acceleration Research Experiment (OARE)

    NASA Technical Reports Server (NTRS)

    Hakimzadeh, Roshanak

    1998-01-01

    The Life and Microgravity Spacelab (LMS) payload flew on the Orbiter Columbia on mission STS-78 from June 20th to July 7th, 1996. The LMS payload on STS-78 was dedicated to life sciences and microgravity experiments. Two accelerometer systems managed by the NASA Lewis Research Center (LERC) flew to support these experiments, namely the Orbital Acceleration Research Experiment (OARE) and the Space Acceleration Measurements System (SAMS). In addition, the Microgravity Measurement Assembly (NOAA), managed by the European Space Research and Technology Center (ESA/ESTEC), and sponsored by NASA, collected acceleration data in support of the experiments on-board the LMS mission. OARE downlinked real-time quasi-steady acceleration data, which was provided to the investigators. The SAMS recorded higher frequency data on-board for post-mission analysis. The MMA downlinked real-time quasi-steady as well as higher frequency acceleration data, which was provided to the investigators. The Principal Investigator Microgravity Services (PIMS) project at NASA LERC supports principal investigators of microgravity experiments as they evaluate the effects of varying acceleration levels on their experiments. A summary report was prepared by PIMS to furnish interested experiment investigators with a guide to evaluate the acceleration environment during STS-78, and as a means of identifying areas which require further study. The summary report provides an overview of the STS-78 mission, describes the accelerometer systems flown on this mission, discusses some specific analyses of the accelerometer data in relation to the various activities which occurred during the mission, and presents plots resulting from these analyses as a snapshot of the environment during the mission. Numerous activities occurred during the STS-78 mission that are of interest to the low-gravity community. Specific activities of interest during this mission were crew exercise, radiator deployment, Vernier Reaction

  20. Intercomparison of nitrogen-containing species in Nimbus 7 LIMS and SAMS Data

    SciTech Connect

    Jackman, C.H.; Guthrie, P.D.; Kaye, J.A.

    1987-01-20

    Nitrogen dioxide (NO/sub 2/) and nitric acid (HNO/sub 3/) distributions were derived with a two-dimensional time-dependent model using N/sub 2/O, CH/sub 4/, and temperature measurements from the stratospheric and mesospheric sounder (SAMS) along with H/sub 2/O measurements from the limb infrared monitor of the stratosphere (LIMS) and O/sub 3/ measurements from the solar backscatter ultraviolet (SBUV) instrument. All three instruments (SAMS, LIMS, and SBUV) were aboard the Nimbus 7 satellite. The computed NO/sub 2/ and HNO/sub 3/ were compared with LIMS NO/sub 2/ and HNO/sub 3/ measurements. Calculated NO/sub 2/ is lower than the LIMS NO/sub 2/ in much of the lower stratosphere by about a factor of 4 or more. Differences in the upper stratosphere between derived NO/sub 2/ and LIMS NO/sub 2/ are within the photochemical uncertainties of the computation. Derived NO/sub 2/ is much larger than LIMS NO/sub 2/ at high latitudes in the upper stratosphere in December, indicating that dynamics and/or photochemistry in the atmosphere are different from those used in the model. Derived HNO/sub 3/ is in fairly good agreement with LIMS HNO/sub 3/ in the upper stratosphere. Derived and LIMS HNO/sub 3/ gradually become more different through the middle stratosphere and reach a fairly substantial disagreement in the lower stratosphere. The high-latitude maxima observed in LIMS HNO/sub 3/ are present at lower altitudes and at higher concentrations than those derived in the model computations. More significantly, the derived HNO/sub 3/ at polar latitudes is highest in the summer while LIMS HNO/sub 3/ is highest in the winter. Disagreements in the lower stratosphere between the computed and LIMS NO/sub 2/ and HNO/sub 3/ can only be reduced if two changes are made in the model computations: (1) additional lower stratospheric sources of odd nitrogen (other than N/sub 2/O+O(/sup 1/D)) are included and (2) a modified chemistry to allow the formation of HNO/sub 3/ at the expense of N/sub 2

  1. The Search for Nitrates on Mars by the Sample Analysis at Mars (SAM) Instrument

    NASA Technical Reports Server (NTRS)

    Navarro-Gonzalez, Rafael; Stern, Jennifer C.; Freissinet, Caroline; McKay, Chirstopher P.; Sutter, Brad; Archer, P. Douglas, Jr.; McAdam, Amy; Franz, Heather; Coll, Partice J.; Glavin, Daniel Patrick; Eigenbrode, Jennifer L.; Wong, Mike; Atreya, Sushiil K.; Wray, James J.; Steele, Andrew; Prats, Benito D.; Szopa, Cyril; Coscia, David; Teinturier, Samuel; Buch, Arnaud; Leshin, Laurie A.; Ming, Douglas W.; Conrad, Pamela Gales; Cabane, Michel; Mahaffy, Paul R.; Grotzinger, John P.

    2013-01-01

    Planetary models suggest that nitrogen was abundant in the early Martian atmosphere as N2 but it was lost by sputtering and photochemical loss to space, impact erosion, and chemical oxidation to nitrates. A nitrogen cycle may exist on Mars where nitrates, produced early in Mars' history, may have been later decomposed back into N2 by the current impact flux. Nitrates are a fundamental source of nitrogen for terrestrial microorganisms, and they have evolved metabolic pathways to perform both oxidation and reduction to drive a complete biological nitrogen cycle. Therefore, the characterization of nitrogen in Martian soils is important to assess habitability of the Martian environment, particularly with respect to the presence of nitrates. The only previous mission that was designed to search for soil nitrates was the Phoenix mission but N-containing species were not detected by TEGA or the MECA WCL. Nitrates have been tentatively identified in Nakhla meteorites, and if nitrogen was oxidized on Mars, this has important implications for the habitability potential of Mars. Here we report the results from the Sample Analysis at Mars (SAM) instrument suite aboard the Curiosity rover during the first year of surface operations in Gale Crater. Samples from the Rocknest aeolian deposit and sedimentary rocks (John Klein) were heated to approx 835degC under helium flow and the evolved gases were analyzed by MS and GC-MS. Two and possibly three peaks may be associated with the release of m/z 30 at temperatures ranging from 180degC to 500degC. M/z 30 has been tentatively identified as NO; other plausible contributions include CH2O and an isotopologue of CO, 12C18O. NO, CH2O, and CO may be reaction products of reagents (MTBSTFA/DMF) carried from Earth for the wet chemical derivatization experiments with SAM and/or derived from indigenous soil nitrogenated organics. Laboratory analyses indicate that it is also possible that <550degC evolved NO is produced via reaction of HCl with

  2. The RNA Binding Protein SAM68 Transiently Localizes in the Chromatoid Body of Male Germ Cells and Influences Expression of Select MicroRNAs

    PubMed Central

    Messina, Valeria; Meikar, Oliver; Paronetto, Maria Paola; Calabretta, Sara; Geremia, Raffaele; Kotaja, Noora; Sette, Claudio

    2012-01-01

    The chromatoid body (CB) is a unique structure of male germ cells composed of thin filaments that condense into a perinuclear organelle after meiosis. Due to the presence of proteins involved in different steps of RNA metabolism and of different classes of RNAs, including microRNAs (miRNAs), the CB has been recently suggested to function as an RNA processing centre. Herein, we show that the RNA binding protein SAM68 transiently localizes in the CB, in concomitance with the meiotic divisions of mouse spermatocytes. Precise staging of the seminiferous tubules and co-localization studies with MVH and MILI, two well recognized CB markers, documented that SAM68 transiently associates with the CB in secondary spermatocytes and early round spermatids. Furthermore, although SAM68 co-immunoprecipitated with MVH in secondary spermatocytes, its ablation did not affect the proper localization of MVH in the CB. On the other hand, ablation of the CB constitutive component MIWI did not impair association of SAM68 with the CB. Isolation of CBs from Sam68 wild type and knockout mouse testes and comparison of their protein content by mass spectrometry indicated that Sam68 ablation did not cause overall alterations in the CB proteome. Lastly, we found that SAM68 interacts with DROSHA and DICER in secondary spermatocytes and early round spermatids and that a subset of miRNAs were altered in Sam68−/−germ cells. These results suggest a novel role for SAM68 in the miRNA pathway during spermatogenesis. PMID:22745822

  3. Reactions Involving Calcium and Magnesium Sulfates as Potential Sources of Sulfur Dioxide During MSL SAM Evolved Gas Analyses

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Knudson, C. A.; Sutter, B.; Franz, H. B.; Archer, P. D., Jr.; Eigenbrode, J. L.; Ming, D. W.; Morris, R. V.; Hurowitz, J. A.; Mahaffy, P. R.; Navarro-Gonzalez, R.

    2016-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) have analyzed several subsamples of <150 micron fines from ten sites at Gale Crater. Three were in Yellowknife Bay: the Rocknest aeolian bedform (RN) and drilled Sheepbed mudstone from sites John Klein (JK) and Cumberland (CB). One was drilled from the Windjana (WJ) site on a sandstone of the Kimberly formation. Four were drilled from sites Confidence Hills (CH), Mojave (MJ), Telegraph Peak (TP) and Buckskin (BK) of the Murray Formation at the base of Mt. Sharp. Two were drilled from sandstones of the Stimson formation targeting relatively unaltered (Big Sky, BY) and then altered (Greenhorn, GH) material associated with a light colored fracture zone. CheMin analyses provided quantitative sample mineralogy. SAM's evolved gas analysis mass spectrometry (EGA-MS) detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases. This contribution will focus on evolved SO2. All samples evolved SO2 above 500 C. The shapes of the SO2 evolution traces with temperature vary between samples but most have at least two "peaks' within the wide high temperature evolution, from approx. 500-700 and approx. 700-860 C (Fig. 1). In many cases, the only sulfur minerals detected with CheMin were Ca sulfates (e.g., RN and GH), which should thermally decompose at temperatures above those obtainable by SAM (>860 C). Sulfides or Fe sulfates were detected by CheMin (e.g., CB, MJ, BK) and could contribute to the high temperature SO2 evolution, but in most cases they are not present in enough abundance to account for all of the SO2. This additional SO2 could be largely associated with x-ray amorphous material, which comprises a significant portion of all samples. It can also be attributed to trace S phases present below the CheMin detection limit, or to reactions which lower the temperatures of SO2 evolution from sulfates that are typically expected to thermally decompose

  4. Detection of Reduced Nitrogen Compounds at Rocknest Using the Sample Analysis At Mars (SAM) Instrument on the Mars Science Laboratory (MSL)

    NASA Technical Reports Server (NTRS)

    Stern, J. C.; Steele, A.; Brunner, A.; Coll, P.; Eigenbrode, J.; Franz, H. B.; Freissinet, C.; Glavin, D.; Jones, J. H.; Navarro-Gonzalez, R.; Mahaffy, P. R.; McAdam, A. C.; McKay, C.; Wray, J.

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected nitrogen-bearing compounds during the pyrolysis of Rocknest material at Gale Crater. Hydrogen cyanide and acetonitrile were identified by the quadrupole mass spectrometer (QMS) both in direct evolved gas analysis (EGA). SAM carried out four separate analyses from Rocknest Scoop 5. A significant low temperature release was present in Rocknest runs 1-4, while a smaller high temperature release was also seen in Rocknest runs 1-3. Here we evaluate whether these compounds are indigenous to Mars or a pyrolysis product resulting from known terrestrial materials that are part of the SAM derivatization.

  5. Multi-layer coatings

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze'ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  6. New insights into the electrochemical desorption of alkanethiol SAMs on gold

    PubMed Central

    Pensa, Evangelina; Vericat, Carolina; Grumelli, Doris; Salvarezza, Roberto C.; Park, Sung Hyun; Longo, Gabriel S.; Szleifer, Igal

    2012-01-01

    A combination of Polarization Modulation Infrared Reflection Absorption Spectroscopy (PMIRRAS) under electrochemical control, Electrochemical Scanning Tunneling Microscopy (ECSTM) and Molecular Dynamics (MD) simulations has been used to shed light on the reductive desorption process of dodecanethiol (C12) and octadecanethiol (C18) SAMs on gold in aqueous electrolytes. Experimental PMIRRAS, ECSTM and MD simulations data for C12 desorption are consistent with formation of randomly distributed micellar aggregates stabilized by Na+ ions, coexisting with a lying-down phase of molecules. The analysis of pit and Au island coverage before and after desorption is consistent with the thiolate-Au adatoms models. On the other hand, PMIRRAS and MD data for C18 indicate that the desorbed alkanethiolates adopt a Na+ ion-stabilized bilayer of interdigitated alkanethiolates, with no evidence of lying down molecules. MD simulations also show that both the degree of order and tilt angle of the desorbed alkanethiolates change with the surface charge on the metal, going from bilayers to micelles. These results demonstrate the complexity of the alkanethiol desorption in the presence of water and the fact that chain length and counterions play a key role in a complex structure. PMID:22870508

  7. Coexistence of the Au(111) reconstruction and a striped phase SAM

    NASA Astrophysics Data System (ADS)

    Darling, S. B.; Rosenbaum, A. W.; Wang, Yi; Sibener, S. J.

    2003-03-01

    We have studied the effect of adsorption of a low-density alkanethiol monolayer on the state of the Au(111) reconstruction [1]. It is commonly believed that the substrate deconstructs following formation of a thiolate SAM, but our results suggest this is not always the case. Neutral atom He diffraction from 1-decanethiol and 1-octanethiol striped phase monolayers is exploited to establish the surface nearest-neighbor spacing and to illustrate a unit cell corresponding to the (23×root3) reconstruction. Moreover, 1/2 -order peaks in the diffraction from C10/Au(111) demonstrate a distinction between neighboring thiolate dimers. These peaks are not observed for the C8/Au(111) system which, in contrast to C10, has no commensurate relation with the reconstruction. STM data are also presented that show persistence of the reconstruction during growth of a C10 striped phase monolayer and no evidence for vacancy islands typically associated with deconstruction until initiation of the standing phase. 1. S.B. Darling, A.W. Rosenbaum, Yi Wang, S.J. Sibener Langmuir 18 (2002) 7462.

  8. SAM II measurements of the polar stratospheric aerosol. Volume 6: April to October 1981

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Brandl, D.

    1985-01-01

    The Stratospheric Aerosol Measurement (SAM) II sensor is aboard the Earth-orbiting Nimbus 7 spacecraft providing extinction measurements of the Antarctic and Arctic stratospheric aerosols with a vertical resolution of 1 km. Representative examples and weekly averages of these aerosol data and corresponding temperature profiles (Apr. 1981 to Oct. 1981) are presented. Contours of aerosol extinction as a function of altitude and longitude or time are plotted and weekly aerosol optical depths are calculated. Stratospheric optical depths are 0.002 to 0.003 for the Antarctic region and 0.006 to 0.007 at the beginning to 0.003 to 0.004 at the end of the time period for the Arctic region. Polar stratospheric clouds at altitudes between the tropopause and 20 km were observed during the Antarctic winter. A ready-to-use format containing a representative sample of the sixth 6 months of data to be used in atmospheric and climatic studies is reported.

  9. Senescence-accelerated Mice (SAMs) as a Model for Brain Aging and Immunosenescence

    PubMed Central

    Shimada, Atsuyoshi; Hasegawa-Ishii, Sanae

    2011-01-01

    The Senescence-Accelerated Mouse (SAM) represents a group of inbred mouse strains developed as a model for the study of human aging and age-related diseases. Senescence-prone (SAMP) strains exhibit an early onset of age-related decline in the peripheral immunity such as thymic involution, loss of CD4+ T cells, impaired helper T cell function, decreased antibody-forming capacity, dysfunction of antigen-presenting cells, decreased natural killer activity, increased auto-antibodies, and susceptibility to virus infection. Senescence-prone SAMP10 mice undergo age-related changes in the brain such as brain atrophy, shrinkage and loss of cortical neurons, retraction of cortical neuronal dendrites, loss of dendritic spines, loss of synapses, impaired learning and memory, depressive behavior, accumulation of neuronal DNA damage, neuronal ubiquitinated inclusions, reduced hippocampal cholinergic receptors, decreased neurotrophic factors, decreased hippocampal zinc and zinc transporters, increased sphyngomyelinase, and elevated oxidative-nitrative stress. Recent data indicating increased pro-inflammatory cytokines in the brain of SAMP10 mice are directing investigators toward an integration of immune and neural abnormalities to enhance understanding of the principles of brain aging. We highlight how mouse brain cells adopt cytokine-mediated responses and how SAMP10 mice are defective in these responses. SAMP10 model would be useful to study how age-related disturbances in peripheral immunity have an impact on dysregulation of brain tissue homeostasis, resulting in age-related neurodegeneration. PMID:22396891

  10. Nimbus-7 Stratospheric and Mesospheric Sounder (SAMS) experiment data user's guide

    NASA Technical Reports Server (NTRS)

    Taylor, F. W.; Rodgers, C. D.; Nutter, S. T.; Oslik, N.

    1989-01-01

    The Stratospheric and Mesospheric Sounder (SAMS) aboard Nimbus-7 observes infrared radiation from the atmospheric limb. Global upper atmosphere temperature profiles and vertical concentrations of H2O, NO, N2O, CH4 and CO2 are derived from these measurements. The status of all channels was carefully monitored. Temperature and composition were retrieved from the measurements by linearizing the direct equation about an a priori profile and using an optimum statistical estimator to find the most likely solution. The derived temperature and composition profiles are archived on two tape products whose file structure and record formats are described in detail. The gridded retrieved temperature tape (GRID-T) contains daily day and night average temperatures at 62 pressure levels in a 2.5 degree latitude by 10 degree longitude grid extending from 67.5 degrees N to 50 degrees S. The zonal mean methane and nitrous oxide composition tape (ZMT-G) contains zonal mean day and night average CH4 and N2O mixing ratios at 31 pressure levels for 2.5 degrees latitude zones extending from 67.5 degrees N to 50 degrees S.

  11. Possible Detection of Nitrates on Mars by the Sample Analysis at Mars (SAM) Instrument

    NASA Technical Reports Server (NTRS)

    Navarro-Gonzalez, R.; Stern, J.; Sutter, B.; Archer, D.; McAdam, A.; Franz, H. B.; McKay, C. P.; Coll, P.; Cabane, M.; Ming, D. W.; Brunner, A. E.; Glavin, D.; Eigenbrode, J. L.; Jones, J. H.; Freissinet, C.; Leshin, L.; Wong, M.; Atreya, S.; Wray, J. J.; Steele, A.; Buch, A.; Prats, B. D.; Szopa, C.; Conrad, P.; Mahaffy, P.

    2013-01-01

    Planetary models suggest that nitrogen was abundant in the early Martian atmosphere as dinitrogen (N2). However, it has been lost by sputtering and photochemical loss to space [1, 2], impact erosion [3], and chemical oxidation to nitrates [4]. Nitrates, produced early in Mars history, are later decomposed back into N2 by the current impact flux [5], making possible a nitrogen cycle on Mars. It is estimated that a layer of about 3 m of pure NaNO3 should be distributed globally on Mars [5]. Nitrates are a fundamental source for nitrogen to terrestrial microorganisms. Therefore, the detection of soil nitrates is important to assess habitability in the Martian environment. The only previous mission that was designed to search for soil nitrates was the Phoenix mission but was unable to detect evolved N-containing species by TEGA and the MECA WCL [6]. Nitrates have been tentatively identified in the Nakhla meteorite [7]. The purpose of this work is to determine if nitrates were detected in first solid sample (Rocknest) in Gale Crater examined by the SAM instrument.

  12. Sulphur-bearing Compounds Detected by MSL SAM Evolved Gas Analysis of Materials from Yellowknife Bay, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Franz, H. B.; Archer, P. D. Jr.; Sutter, B.; Eigenbrode, J. L.; Freissinet, C.; Atreya, S. K.; Bish, D. L.; Blake, D. F.; Brunner, A.; Mahaffy, P. R.; Ming, D. W.; Morris, R. V.; Navarro-Gonzalez, R.; Rampe, E. B.; Steele, A.; Wray, J. J.

    2014-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) analysed several subsamples of sample fines (<150 µm) from three sites in Yellowknife Bay, an aeolian bedform termed Rocknest (hereafter "RN") and two samples drilled from the Sheepbed mudstone at sites named John Klein ("JK") and Cumberland ("CB"). SAM's evolved gas analysis (EGA) mass spectrometry detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, OCS, CS2 and other trace gases. The identity of evolved gases and temperature (T) of evolution can support mineral detection by CheMin and place constraints on trace volatile-bearing phases present below the CheMin detection limit or difficult to characterize with XRD (e.g., X-ray amorphous phases). Here, we focus on potential constraints on phases that evolved SO2, H2S, OCS, and CS2 during thermal analysis.

  13. DNA methylation signature (SAM40) identifies subgroups of the Luminal A breast cancer samples with distinct survival

    PubMed Central

    Aure, Miriam Ragle; Louhimo, Riku; Pladsen, Arne V.; Ottestad, Lars; Touleimat, Nizar; Laakso, Marko; Halvorsen, Ann Rita; Alnæs, Grethe I. Grenaker; Riis, Margit L.H.; Helland, Åslaug; Hautaniemi, Sampsa; Lønning, Per Eystein; Naume, Bjørn; Børresen-Dale, Anne-Lise; Tost, Jörg; Kristensen, Vessela N.

    2017-01-01

    Breast cancer patients with Luminal A disease generally have a good prognosis, but among this patient group are patients with good prognosis that are currently overtreated with adjuvant chemotherapy, and also patients that have a bad prognosis and should be given more aggressive treatment. There is no available method for subclassification of this patient group. Here we present a DNA methylation signature (SAM40) that segregates Luminal A patients based on prognosis, and identify one good prognosis group and one bad prognosis group. The prognostic impact of SAM40 was validated in four independent patient cohorts. Being able to subdivide the Luminal A patients may give the two-sided benefit of identifying one subgroup that may benefit from a more aggressive treatment than what is given today, and importantly, identifying a subgroup that may benefit from less treatment. PMID:27911866

  14. On the Role of Additional [4Fe-4S] Clusters with a Free Coordination Site in Radical-SAM Enzymes

    PubMed Central

    Mulliez, Etienne; Duarte, Victor; Arragain, Simon; Fontecave, Marc; Atta, Mohamed

    2017-01-01

    The canonical CysXXXCysXXCys motif is the hallmark of the Radical-SAM superfamily. This motif is responsible for the ligation of a [4Fe-4S] cluster containing a free coordination site available for SAM binding. The five enzymes MoaA, TYW1, MiaB, RimO and LipA contain in addition a second [4Fe-4S] cluster itself bound to three other cysteines and thus also displaying a potentially free coordination site. This review article summarizes recent important achievements obtained on these five enzymes with the main focus to delineate the role of this additional [4Fe-4S] cluster in catalysis. PMID:28361051

  15. Maturation of nitrogenase cofactor—the role of a class E radical SAM methyltransferase NifB

    PubMed Central

    Hu, Yilin; Ribbe, Markus W.

    2016-01-01

    Nitrogenase catalyzes the important reactions of N2-, CO- and CO2-reduction at its active cofactor site. Designated the M-cluster, this complex metallocofactor is assembled through the generation of a characteristic 8Fe-core prior to the insertion of Mo and homocitrate that completes the stoichiometry of the M-cluster. NifB catalyzes the critical step of radical SAM-dependent carbide insertion that occurs concomitant with the insertion a “9th” sulfur and the rearrangement/coupling of two 4Fe-clusters into a complete 8Fe-core of the M-cluster. Further categorization of a family of NifB proteins as a new class of radical SAM methyltransferases suggests a general function of these proteins in complex metallocofactor assembly and provides a new platform for unveiling unprecedented chemical reactions catalyzed by biological systems. PMID:26969410

  16. An intact SAM-dependent methyltransferase fold is encoded by the human endothelin-converting enzyme-2 gene

    SciTech Connect

    Tempel, W.; Wu, H.; Dombrovsky, L.; Zeng, H.; Loppnau, P.; Zhu, H.; Plotnikov, A.N.; Bochkarev, A.

    2010-08-17

    A recent survey of protein expression patterns in patients with Alzheimer's disease (AD) has identified ece2 (chromosome: 3; Locations: 3q27.1) as the most significantly downregulated gene within the tested group. ece2 encodes endothelin-converting enzyme ECE2, a metalloprotease with a role in neuropeptide processing. Deficiency in the highly homologous ECE1 has earlier been linked to increased levels of AD-related {beta}-amyloid peptide in mice, consistent with a role for ECE in the degradation of that peptide. Initially, ECE2 was presumed to resemble ECE1, in that it comprises a single transmembrane region of {approx}20 residues flanked by a small amino-terminal cytosolic segment and a carboxy-terminal lumenar peptidase domain. The carboxy-terminal domain has significant sequence similarity to both neutral endopeptidase, for which an X-ray structure has been determined, and Kell blood group protein. After their initial discovery, multiple isoforms of ECE1 and ECE2 were discovered, generated by alternative splicing of multiple exons. The originally described ece2 transcript, RefSeq NM{_}174046, contains the amino-terminal cytosolic portion followed by the transmembrane region and peptidase domain (Fig. 1, isoform B). Another ece2 transcript, available from the Mammalian Gene Collection under MGC2408 (Fig. 1, isoform C), RefSeq accession NM{_}032331, is predicted to be translated into a 255 residue peptide with low but detectable sequence similarity to known S-adenosyl-L-methionine (SAM)-dependent methyltransferases (SAM-MTs), such as the hypothetical protein TT1324 from Thermus thermophilis, PDB code 2GS9, which shares 30% amino acid sequence identity with ECE2 over 138 residues of the sequence. Intriguingly, another 'elongated' ece2 transcript (Fig. 1, isoform A) (RefSeq NM{_}014693) contains an amino-terminal portion of the putative SAM-MT domain, the transmembrane domain, and the protease domain. This suggests the possibility for coexistence of the putative SAM

  17. Review and standardization of cell phone exposure calculations using the SAM phantom and anatomically correct head models

    PubMed Central

    Beard, Brian B; Kainz, Wolfgang

    2004-01-01

    We reviewed articles using computational RF dosimetry to compare the Specific Anthropomorphic Mannequin (SAM) to anatomically correct models of the human head. Published conclusions based on such comparisons have varied widely. We looked for reasons that might cause apparently similar comparisons to produce dissimilar results. We also looked at the information needed to adequately compare the results of computational RF dosimetry studies. We concluded studies were not comparable because of differences in definitions, models, and methodology. Therefore we propose a protocol, developed by an IEEE standards group, as an initial step in alleviating this problem. The protocol calls for a benchmark validation study comparing the SAM phantom to two anatomically correct models of the human head. It also establishes common definitions and reporting requirements that will increase the comparability of all computational RF dosimetry studies of the human head. PMID:15482601

  18. Benchmark Simulations of the Thermal-Hydraulic Responses during EBR-II Inherent Safety Tests using SAM

    SciTech Connect

    Hu, Rui; Sumner, Tyler S.

    2016-01-01

    An advanced system analysis tool SAM is being developed for fast-running, improved-fidelity, and wholeplant transient analyses at Argonne National Laboratory under DOE-NE’s Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. As an important part of code development, companion validation activities are being conducted to ensure the performance and validity of the SAM code. This paper presents the benchmark simulations of two EBR-II tests, SHRT-45R and BOP- 302R, whose data are available through the support of DOE-NE’s Advanced Reactor Technology (ART) program. The code predictions of major primary coolant system parameter are compared with the test results. Additionally, the SAS4A/SASSYS-1 code simulation results are also included for a code-to-code comparison.

  19. Detection of Nitric Oxide by the Sample Analysis at Mars (SAM) Instrument Implications for the Presence of Nitrates

    NASA Technical Reports Server (NTRS)

    Navarro-Gonzalez, R.; Stern, J.; Freissinet, C.; Franz, H. B.; Eigenbrode, J. L..; McKay, C. P.; Coll, P.; Sutter, B.; Archer, D.; McAdam, A.; Cabane, M.; Ming, D. W.; Glavin, D.; Leshin, L.; Wong, M.; Atreya, S.; Wray, J. J.; Steele, A.; Buch, A.; Prats, B. D.; Szopa, C.; Coscia, D.; Teinturier, S.; Conrad, P.; Owen, T. C.; Mahaffy, P.; Grotzinger, J. P.

    2014-01-01

    One of the main goals of the Mars Science Laboratory is to determine whether the planet ever had environmental conditions able to support microbial life. Nitrogen is a fundamental element for life, and is present in structural (e.g., proteins), catalytic (e.g., enzymes and ribozymes), energy transfer (e.g., ATP) and information storage (RNA and DNA) biomolecules. Planetary models suggest that molecular nitrogen was abundant in the early Martian atmosphere, but was rapidly lost to space by photochemistry, sputtering impact erosion, and oxidized and deposited to the surface as nitrate. Nitrates are a fundamental source for nitrogen to terrestrial microorganisms. Therefore, the detection of nitrates in soils and rocks is important to assess the habitability of a Martian environment. SAM is capable of detecting nitrates by their thermal decomposition into nitric oxide, NO. Here we analyze the release of NO from soils and rocks examined by the SAM instrument at Gale crater, and discuss its origin.

  20. Revision of middle Proterozoic Yellowjacket Formation, central Idaho, and revision of Cretaceous Slim Sam Formation, Elkhorn mountains area, Montana

    USGS Publications Warehouse

    Tysdal, Russell G.

    2000-01-01

    The Yellowjacket Formation is restricted to the strata originally assigned to it by Ross (1934). The Yellowjacket, the conformably overlying Hoodoo Quartzite, and succeeding unnamed argillaceous quartzite unit form a genetically related sequence that lies in a structural block delimited on the northeast by the Iron Lake fault. Directly northeast of the fault, strata currently assigned by others to the lower subunit of the Yellowjacket are correlated with the Apple Creek Formation in the Lemhi Range. Mapping in the western part of the Lemhi Range shows that the Apple Creek Formation lies depositionally above the Big Creek Formation and that no rocks of the Yellowjacket-Hoodoo unnamed unit stratigraphic sequence are present. In contrast, in the area of the Yellowjacket mapped by Ross (1934) and the area directly northeast of the Iron Lake Fault, the Big Creek Formation is absent, even though it is 2,700 m thick in the Lemhi Range. These data indicate that the Iron Lake Fault juxtaposed the Yellowjacket-Hoodoo-unnamed unit sequence against non-Yellowjacket strata to the northeast. The Upper Cretaceous Slim Sam Formation of the Elkhorn Mountains area is revised. Strata of the lower part are correlated with the regionally recognized marine Telegraph Creek Formation and the overlying marine to marginal marine Eagle Sandstone. Only lower strata of the Eagle are present in the study area and they are preserved discontinously. The nonmarine volcanic and volcaniclastic rocks of the upper part of the Slim Sam as originally defined retain the name Slim Sam Formation. These rocks, mainly of sedimentary origin, are genetically related to the Elkhorn Mountains Volcanics. The lower contact of the Slim Sam (restricted) is unconformable above the Eagle Sandstone or more commonly above the Telegraph Creek Formation. The upper contact is conformable with the Elkhorn Mountains Volcanics.

  1. Structural basis of RNA recognition and dimerization by the STAR proteins T-STAR and Sam68

    PubMed Central

    Feracci, Mikael; Foot, Jaelle N.; Grellscheid, Sushma N.; Danilenko, Marina; Stehle, Ralf; Gonchar, Oksana; Kang, Hyun-Seo; Dalgliesh, Caroline; Meyer, N. Helge; Liu, Yilei; Lahat, Albert; Sattler, Michael; Eperon, Ian C.; Elliott, David J.; Dominguez, Cyril

    2016-01-01

    Sam68 and T-STAR are members of the STAR family of proteins that directly link signal transduction with post-transcriptional gene regulation. Sam68 controls the alternative splicing of many oncogenic proteins. T-STAR is a tissue-specific paralogue that regulates the alternative splicing of neuronal pre-mRNAs. STAR proteins differ from most splicing factors, in that they contain a single RNA-binding domain. Their specificity of RNA recognition is thought to arise from their property to homodimerize, but how dimerization influences their function remains unknown. Here, we establish at atomic resolution how T-STAR and Sam68 bind to RNA, revealing an unexpected mode of dimerization different from other members of the STAR family. We further demonstrate that this unique dimerization interface is crucial for their biological activity in splicing regulation, and suggest that the increased RNA affinity through dimer formation is a crucial parameter enabling these proteins to select their functional targets within the transcriptome. PMID:26758068

  2. Exploration of the Habitability of Mars with the SAM Suite Investigation on the 2009 Mars Science Laboratory

    NASA Technical Reports Server (NTRS)

    Mahaffy, P. R.; Cabane, M.; Webster, C. R.

    2008-01-01

    The 2009 Mars Science Laboratory (MSL) with a substantially larger payload capability that any other Mars rover, to date, is designed to quantitatively assess a local region on Mars as a potential habitat for present or past life. Its goals are (1) to assess past or present biological potential of a target environment, (2) to characterize geology and geochemistry at the MSL landing site, and (3) to investigate planetary processes that influence habitability. The Sample Analysis at Mars (SAM) Suite, in its final stages of integration and test, enables a sensitive search for organic molecules and chemical and isotopic analysis of martian volatiles. MSL contact and remote surface and subsurface survey Instruments establish context for these measurements and facilitate sample identification and selection. The SAM instruments are a gas chromatograph (GC), a mass spectrometer (MS), and a tunable laser spectrometer (TLS). These together with supporting sample manipulation and gas processing devices are designed to analyze either the atmospheric composition or gases extracted from solid phase samples such as rocks and fines. For example, one of the core SAM experiment sequences heats a small powdered sample of a Mars rock or soil from ambient to -1300 K in a controlled manner while continuously monitoring evolved gases. This is followed by GCMS analysis of released organics. The general chemical survey is complemented by a specific search for molecular classes that may be relevant to life including atmospheric methane and its carbon isotope with the TLS and biomarkers with the GCMS.

  3. Structural basis of RNA recognition and dimerization by the STAR proteins T-STAR and Sam68.

    PubMed

    Feracci, Mikael; Foot, Jaelle N; Grellscheid, Sushma N; Danilenko, Marina; Stehle, Ralf; Gonchar, Oksana; Kang, Hyun-Seo; Dalgliesh, Caroline; Meyer, N Helge; Liu, Yilei; Lahat, Albert; Sattler, Michael; Eperon, Ian C; Elliott, David J; Dominguez, Cyril

    2016-01-13

    Sam68 and T-STAR are members of the STAR family of proteins that directly link signal transduction with post-transcriptional gene regulation. Sam68 controls the alternative splicing of many oncogenic proteins. T-STAR is a tissue-specific paralogue that regulates the alternative splicing of neuronal pre-mRNAs. STAR proteins differ from most splicing factors, in that they contain a single RNA-binding domain. Their specificity of RNA recognition is thought to arise from their property to homodimerize, but how dimerization influences their function remains unknown. Here, we establish at atomic resolution how T-STAR and Sam68 bind to RNA, revealing an unexpected mode of dimerization different from other members of the STAR family. We further demonstrate that this unique dimerization interface is crucial for their biological activity in splicing regulation, and suggest that the increased RNA affinity through dimer formation is a crucial parameter enabling these proteins to select their functional targets within the transcriptome.

  4. HPA and SAM axis responses as correlates of self- vs parental ratings of anxiety in boys with an Autistic Disorder.

    PubMed

    Bitsika, Vicki; Sharpley, Christopher F; Sweeney, John A; McFarlane, James R

    2014-03-29

    Anxiety and Autistic Disorder (AD) are both neurological conditions and both disorders share some features that make it difficult to precisely allocate specific symptoms to each disorder. HPA and SAM axis activities have been conclusively associated with anxiety, and may provide a method of validating anxiety rating scale assessments given by parents and their children with AD about those children. Data from HPA axis (salivary cortisol) and SAM axis (salivary alpha amylase) responses were collected from a sample of 32 high-functioning boys (M age=11yr) with an Autistic Disorder (AD) and were compared with the boys' and their mothers' ratings of the boys' anxiety. There was a significant difference between the self-ratings given by the boys and ratings given about them by their mothers. Further, only the boys' self-ratings of their anxiety significantly predicted the HPA axis responses and neither were significantly related to SAM axis responses. Some boys showed cortisol responses which were similar to that previously reported in children who had suffered chronic and severe anxiety arising from stressful social interactions. As well as suggesting that some boys with an AD can provide valid self-assessments of their anxiety, these data also point to the presence of very high levels of chronic HPA-axis arousal and consequent chronic anxiety in these boys.

  5. Characterization of the attP site of the integrative element pSAM2 from Streptomyces ambofaciens.

    PubMed

    Raynal, Alain; Friedmann, Annick; Tuphile, Karine; Guerineau, Michel; Pernodet, Jean-Luc

    2002-01-01

    pSAM2 is integrated into the Streptomyces ambofaciens chromosome through site-specific recombination between the element (attP) and the chromosomal (attB) site. The 43 kDa integrase protein encoded by pSAM2 catalyses this recombination event. Tools have been developed to study site-specific recombination in Escherichia coli. In vivo studies showed that a 360 bp fragment of attP is required for efficient site-specific recombination and that int can be provided in trans. pSAM2 integrase was purified and overexpressed in E. coli and Int binding at the attP site was studied. DNaseI footprinting revealed two sites that bind integrase strongly and appear to be symmetrical with regard to the core site. These two P1/P2 arm-type sites both contain a 17 bp motif that is identical except at one position, GTCACGCAG(A/T)TAGACAC. P1 and P2 are essential for site-specific recombination.

  6. \\tLaboratory Environmental Sample Disposal Information Document - Companion to Standardized Analytical Methods for Environmental Restoration Following Homeland Security Events (SAM) – Revision 5.0

    EPA Pesticide Factsheets

    Document is intended to provide general guidelines for use byEPA and EPA-contracted laboratories when disposing of samples and associated analytical waste following use of the analytical methods listed in SAM.

  7. In situ Analysis of Organic Matter in Martian Soil: Laboratory Measurements Under Martian Operating Conditions Supporting Treatment and Interpretation of SAM GC-MS Data

    NASA Astrophysics Data System (ADS)

    Millan, M.; Szopa, C.; Coll, P.; Buch, A.; Cabane, M.; Coscia, D.; Glavin, D. P.; Freissinet, C.

    2014-07-01

    This work presents laboratory measurements under martian operating conditions in comparison with the SAM GC-MS data provided by the Curiosity rover. Their treatment and interpretation supports the in situ analysis of organic matter on Mars.

  8. Possible Origin of Chlorobenzene Detected by SAM Instrument at Gale Crater, Mars: Synergy of Iron Oxides and Perchlorate and Consequences for Organic Matter Analysis

    NASA Astrophysics Data System (ADS)

    Francois, P.; Coll, P.; Szopa, C.; Georgelin, T.; Buch, A.; Freissinet, C.; Belmahdi, I.; McAdam, A.; Eigenbrode, J.; Glavin, D.; Kashyap, S.; Navarro-Gonzalez, A. R.; Mahaffy, P.; Cabane, M.

    2014-07-01

    Chlorobenzene, potentially of martian origin, has been detected by the SAM experiment onboard Curiosity rover. We explore its potential formation by a synergy between oxychlorine phases and iron oxides in the presence of a carbon source.

  9. Flow coating apparatus and method of coating

    SciTech Connect

    Hanumanthu, Ramasubrahmaniam; Neyman, Patrick; MacDonald, Niles; Brophy, Brenor; Kopczynski, Kevin; Nair, Wood

    2014-03-11

    Disclosed is a flow coating apparatus, comprising a slot that can dispense a coating material in an approximately uniform manner along a distribution blade that increases uniformity by means of surface tension and transfers the uniform flow of coating material onto an inclined substrate such as for example glass, solar panels, windows or part of an electronic display. Also disclosed is a method of flow coating a substrate using the apparatus such that the substrate is positioned correctly relative to the distribution blade, a pre-wetting step is completed where both the blade and substrate are completed wetted with a pre-wet solution prior to dispensing of the coating material onto the distribution blade from the slot and hence onto the substrate. Thereafter the substrate is removed from the distribution blade and allowed to dry, thereby forming a coating.

  10. Apparatus for coating powders

    DOEpatents

    Makowiecki, Daniel M.; Kerns, John A.; Alford, Craig S.; McKernan, Mark A.

    2000-01-01

    A process and apparatus for coating small particles and fibers. The process involves agitation by vibrating or tumbling the particles or fibers to promote coating uniformly, removing adsorbed gases and static charges from the particles or fibers by an initial plasma cleaning, and coating the particles or fibers with one or more coatings, a first coating being an adhesion coating, and with subsequent coatings being deposited in-situ to prevent contamination at layer interfaces. The first coating is of an adhesion forming element (i.e. W, Zr, Re, Cr, Ti) of a 100-10,000 .ANG. thickness and the second coating or final coating of a multiple (0.1-10 microns) being Cu or Ag, for example for brazing processes, or other desired materials that defines the new surface related properties of the particles. An essential feature of the coating process is the capability to deposit in-situ without interruption to prevent the formation of a contaminated interface that could adversely affect the coating adhesion. The process may include screening of the material to be coated and either continuous or intermittent vibration to prevent agglomeration of the material to be coated.

  11. The Study of Active Monitoring in Sweden (SAMS): A randomized study comparing two different follow-up schedules for active surveillance of low-risk prostate cancer

    PubMed Central

    Carlsson, Stefan; Holmberg, Erik; Holmberg, Lars; Johansson, Eva; Josefsson, Andreas; Nilsson, Annika; Nyberg, Maria; Robinsson, David; Sandberg, Jonas; Sandblom, Dag; Stattin, Pär

    2013-01-01

    Objective Only a minority of patients with low-risk prostate cancer needs treatment, but the methods for optimal selection of patients for treatment are not established. This article describes the Study of Active Monitoring in Sweden (SAMS), which aims to improve those methods. Material and methods SAMS is a prospective, multicentre study of active surveillance for low-risk prostate cancer. It consists of a randomized part comparing standard rebiopsy and follow-up with an extensive initial rebiopsy coupled with less intensive follow-up and no further scheduled biopsies (SAMS-FU), as well as an observational part (SAMS-ObsQoL). Quality of life is assessed with questionnaires and compared with patients receiving primary curative treatment. SAMS-FU is planned to randomize 500 patients and SAMS-ObsQoL to include at least 500 patients during 5 years. The primary endpoint is conversion to active treatment. The secondary endpoints include symptoms, distant metastases and mortality. All patients will be followed for 10–15 years. Results Inclusion started in October 2011. In March 2013, 148 patients were included at 13 Swedish urological centres. Conclusions It is hoped that the results of SAMS will contribute to fewer patients with indolent, low-risk prostate cancer receiving unnecessary treatment and more patients on active surveillance who need treatment receiving it when the disease is still curable. The less intensive investigational follow-up in the SAMS-FU trial would reduce the healthcare resources allocated to this large group of patients if it replaced the present standard schedule. PMID:23883427

  12. Tribology and hydrophobicity of a biocompatible GPTMS/PFPE coating on Ti6Al4V surfaces.

    PubMed

    Panjwani, Bharat; Sinha, Sujeet K

    2012-11-01

    Tribological properties of perfluoropolyether (PFPE) coated 3-glycidoxypropyltrimethoxy silane (GPTMS) SAMs (self-assembled monolayers) onto Ti6Al4V alloy substrate were studied using ball-on-disk experiments. GPTMS SAMs deposition onto a Ti6Al4V alloy surface was carried out using solution phase method. Ultra-thin layer of PFPE was dip-coated onto SAMs modified specimens. Tribological tests were carried out at 0.2 N normal load and rotational speed of 200 rpm using track radius of 2 mm. Wear track and counterface surface conditions were investigated using optical microscopy. PFPE modified specimens were baked at 150 °C for 1h to investigate the effect of thermal treatment on tribological properties. Surface characterization tests such as contact angle measurement, AFM morphology and X-ray photoelectron spectroscopy were carried out for differently modified specimens. PFPE overcoat meets the requirements of cytotoxicity test using the ISO 10993-5 elution method. PFPE top layer lowered the coefficient of friction and increased wear durability for different specimens (with and without GPTMS intermediate layer). PFPE overcoat onto GPTMS showed significant increase in the wear resistance compared with overcoat onto bare Ti6Al4V specimens. The observed improvement in the tribological properties can be attributed to the change in the interaction of PFPE molecules with the substrate surface due to the GPTMS intermediate layer.

  13. Cloning of Frankia species putative tRNA(Pro) genes and their efficacy for pSAM2 site-specific integration in Streptomyces lividans.

    PubMed

    Alegre, M T; Cournoyer, B; Mesas, J M; Guérineau, M; Normand, P; Pernodet, J L

    1994-12-01

    pSAM2 is a conjugative Streptomyces ambofaciens mobile genetic element that can transfer and integrate site specifically in the genome. The chromosomal attachment site (attB) for pSAM2 site-specific recombination for two Frankia species was analyzed. It overlaps putative proline tRNA genes having a 3'-terminal CCA sequence, an uncommon feature among actinomycetes. pSAM2 is able to integrate into a cloned Frankia attB site harbored in Streptomyces lividans. The integration event removes the 3'-terminal CCA sequence and introduces a single nucleotide difference in the T psi C loop of the putative Frankia tRNA(Pro) gene. Major differences between the attP sequence from pSAM2 and the Frankia attB sequence restrict the identity segment to a 43-bp-long region. Only one mismatch is found between these well-conserved att segments. This nucleotide substitution makes a BstBI recognition site in Frankia attB and was used to localize the recombination site in a 25-bp region going from the anticodon to the T psi C loop of the tRNA(Pro) sequence. Integration of pSAM2 into the Frankia attB site is the first step toward introduction of pSAM2 derivatives into Frankia spp.

  14. Cloning of Frankia species putative tRNA(Pro) genes and their efficacy for pSAM2 site-specific integration in Streptomyces lividans.

    PubMed Central

    Alegre, M T; Cournoyer, B; Mesas, J M; Guérineau, M; Normand, P; Pernodet, J L

    1994-01-01

    pSAM2 is a conjugative Streptomyces ambofaciens mobile genetic element that can transfer and integrate site specifically in the genome. The chromosomal attachment site (attB) for pSAM2 site-specific recombination for two Frankia species was analyzed. It overlaps putative proline tRNA genes having a 3'-terminal CCA sequence, an uncommon feature among actinomycetes. pSAM2 is able to integrate into a cloned Frankia attB site harbored in Streptomyces lividans. The integration event removes the 3'-terminal CCA sequence and introduces a single nucleotide difference in the T psi C loop of the putative Frankia tRNA(Pro) gene. Major differences between the attP sequence from pSAM2 and the Frankia attB sequence restrict the identity segment to a 43-bp-long region. Only one mismatch is found between these well-conserved att segments. This nucleotide substitution makes a BstBI recognition site in Frankia attB and was used to localize the recombination site in a 25-bp region going from the anticodon to the T psi C loop of the tRNA(Pro) sequence. Integration of pSAM2 into the Frankia attB site is the first step toward introduction of pSAM2 derivatives into Frankia spp. PMID:7811067

  15. SAM: String-based sequence search algorithm for mitochondrial DNA database queries

    PubMed Central

    Röck, Alexander; Irwin, Jodi; Dür, Arne; Parsons, Thomas; Parson, Walther

    2011-01-01

    The analysis of the haploid mitochondrial (mt) genome has numerous applications in forensic and population genetics, as well as in disease studies. Although mtDNA haplotypes are usually determined by sequencing, they are rarely reported as a nucleotide string. Traditionally they are presented in a difference-coded position-based format relative to the corrected version of the first sequenced mtDNA. This convention requires recommendations for standardized sequence alignment that is known to vary between scientific disciplines, even between laboratories. As a consequence, database searches that are vital for the interpretation of mtDNA data can suffer from biased results when query and database haplotypes are annotated differently. In the forensic context that would usually lead to underestimation of the absolute and relative frequencies. To address this issue we introduce SAM, a string-based search algorithm that converts query and database sequences to position-free nucleotide strings and thus eliminates the possibility that identical sequences will be missed in a database query. The mere application of a BLAST algorithm would not be a sufficient remedy as it uses a heuristic approach and does not address properties specific to mtDNA, such as phylogenetically stable but also rapidly evolving insertion and deletion events. The software presented here provides additional flexibility to incorporate phylogenetic data, site-specific mutation rates, and other biologically relevant information that would refine the interpretation of mitochondrial DNA data. The manuscript is accompanied by freeware and example data sets that can be used to evaluate the new software (http://stringvalidation.org). PMID:21056022

  16. MSL/SAM Measurements of Non Condensable Volatiles, Comparison with Viking Lander, and Implications for Seasonal Cycle

    NASA Astrophysics Data System (ADS)

    Atreya, Sushil; Squyres, Steve; Mahaffy, Paul; Leshin, Laurie; Franz, Heather; Trainer, Melissa; Wong, Michael; McKay, Christopher; Navarro-Gonzalez, Rafael; ScienceTeam, MarsScienceLab

    2013-04-01

    The first measurements of the composition of the Martian atmosphere above Gale Crater by the Sample Analysis at Mars (SAM) instrument on Curiosity Rover revealed that although the volume mixing ratios (vmr) of the gases are generally similar to those measured by the Viking Lander 2 (VL2) thirty five years ago [2], they are notably different for N2 and 40Ar [1]. SAM finds a vmr of 1.9% each for N2 and Ar, so that N2 is 30% lower while Ar is 21% greater than the corresponding VL2 values, resulting in a 40% lower N2/Ar ratio compared to the VL2 result. The Ar/N ratio is used to assess the degree of mixing between the Martian atmosphere and the internal gas component of Mars meteorites due to the shock of impact ejection [e.g. 3]. The above differences in N2 and 40Ar seem to result either from different instrument characteristics or time variable atmospheric phenomena or both. The VL2 data were taken during northern summer (48°N, Ls=135°), whereas the SAM measurements correspond to the beginning of spring season (4.5°S, Ls=182-190°). Previous observations by Mars Odyssey Gamma Ray Spectrometer over three years have shown that the Ar mixing ratio increased by a factor of 6 over the south polar region in the winter [4]. However, the data are controversial for the equatorial region, ranging from no seasonal change [4] to as much as a 35% change [5]. No significant change was seen between the equator (SAM) and the midlatitude northern summer (VL2), however [4]. Thus the difference between the SAM and VL2 Ar does not appear to be related to different seasons. On the other hand, the vmr's of non-condensable volatiles (NCV), N2, Ar and CO, at any latitude are expected to vary seasonally due to the annual, global CO2 cycle. Diurnal changes are not expected, considering the long lifetimes of NCV's that exceed the martian year [6]. In addition to Ar, seasonal changes have been recorded in CO from ground-based [7] and MRO/CRISM observations [8], but show a much smaller

  17. Corrosion Characterization of Iron-Based High-Performance Amorphous-Metal Thermal-Spray Coatings

    SciTech Connect

    Farmer, J C; Haslam, J J; Day, S D; Branagan, D J; Blue, C A; Rivard, J K; Aprigliano, L F; Yang, N; Perepezko, J H; Beardsley, M B

    2005-03-21

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. One of these compositions, SAM1651, is discussed in detail to illustrate the promise of this general class of materials.

  18. Elaboration of composite and chemically heterogeneous icephobic coatings

    NASA Astrophysics Data System (ADS)

    Arianpour, Faranak

    consequence of HCs preparation, via different methods, was observed in low contact angle hysteresis (CAH) values. The prepared HCs by self assembled monolayers ( SAMs), nanoparticles and "masked" plasma sputtering methods resulted in reducing the ice adhesion strength by factors of ~ 3, ~ 1.7 and ~ 1.3 times, respectively, compared to a polished aluminum sample. The durability of coatings was studied under accelerated aging conditions such as UV degradation, several icing/de-icing cycles and immersion in distilled water and different pH solutions. Consequently, based on results obtained it was observed that the HCs are more stable under accelerated aging conditions compared to homogeneous coatings.

  19. Improved Polyimide Intumescent Coating

    NASA Technical Reports Server (NTRS)

    Salyer, I. O.; Fox, L. B.

    1984-01-01

    New polyimide intumescent coating uses titanium dioxide and glass microballons as nucleating agents to improve foaming characteristics of commercially-available polyimide precursor resin. Used for coating interior surfaces in commercial aircraft.

  20. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1984-01-01

    A high temperature oxidation resistant, thermal barrier coating system is disclosed for a nickel cobalt, or iron base alloy substrate. An inner metal bond coating contacts the substrate, and a thermal barrier coating covers the bond coating. NiCrAlR, FeCrAlR, and CoCrAlR alloys are satisfactory as bond coating compositions where R=Y or Yb. These alloys contain, by weight, 24.9-36.7% chromium, 5.4-18.5% aluminum, and 0.05 to 1.55% yttrium or 0.05 to 0.53% ytterbium. The coatings containing ytterbium are preferred over those containing yttrium. An outer thermal barrier coating of partial stabilized zirconium oxide (zirconia) which is between 6% and 8%, by weight, of yttrium oxide (yttria) covers the bond coating. Partial stabilization provides a material with superior durability. Partially stabilized zirconia consists of mixtures of cubic, tetragonal, and monoclinic phases.

  1. Coating Galvanized Steel

    DTIC Science & Technology

    1989-06-01

    phenolic drying oil products with a zinc dust-zinc oxide pigmentation. Roebuck et al. (Ref 3), state "For instance, coatings subject to saponification ...coating. All three types of TT-P-641 are subject to saponification , since they con- tain drying oils. The General Services Administration (GSA) sells con...penetration " Chemical degradation of coatings, particularly saponification of alkyd coatings in an alkaline environment " Differences in expansion and

  2. METHOD FOR TESTING COATINGS

    DOEpatents

    Johns, I.B.; Newton, A.S.

    1958-09-01

    A method is described for detecting pin hole imperfections in coatings on uranium-metal objects. Such coated objects are contacted with a heated atmosphere of gaseous hydrogen and imperfections present in the coatings will allow the uranlum to react with the hydrogen to form uranium hydride. Since uranium hydride is less dense than uranium metal it will swell, causing enlargement of the coating defeot and rendering it visible.

  3. Characterization of RSI coating

    NASA Technical Reports Server (NTRS)

    Miller, A. D.; Garofalini, S. H.; Smiser, L. W.; Mueller, J. I.

    1973-01-01

    X-ray diffraction analyses on mullite, silica, and ceramic mullite fiber coating materials to investigate the effects of thermal cycling, show that ceramic mullite fiber coating porosity is little affected by cycling to 1250 C and that material pores are mostly smaller than 15 nm. Some mullite coatings experience a slight increase in crystobalite with somewhat increased porosity. Silica coatings show a marked tendency to precipitate cristobalite with increased porosity and dimensional instability.

  4. Even the Odd Numbers Help: Failure Modes of SAM-Based Tunnel Junctions Probed via Odd-Even Effects Revealed in Synchrotrons and Supercomputers.

    PubMed

    Thompson, Damien; Nijhuis, Christian A

    2016-10-18

    This Account describes a body of research in atomic level design, synthesis, physicochemical characterization, and macroscopic electrical testing of molecular devices made from ferrocene-functionalized alkanethiol molecules, which are molecular diodes, with the aim to identify, and resolve, the failure modes that cause leakage currents. The mismatch in size between the ferrocene headgroup and alkane rod makes waxlike highly dynamic self-assembled monolayers (SAMs) on coinage metals that show remarkable atomic-scale sensitivity in their electrical properties. Our results make clear that molecular tunnel junction devices provide an excellent testbed to probe the electronic and supramolecular structures of SAMs on inorganic substrates. Contacting these SAMs to a eutectic "EGaIn" alloy top-electrode, we designed highly stable long-lived molecular switches of the form electrode-SAM-electrode with robust rectification ratios of up to 3 orders of magnitude. The graphic that accompanies this conspectus displays a computed SAM packing structure, illustrating the lollipop shape of the molecules that gives dynamic SAM supramolecular structures and also the molecule-electrode van der Waals (vdW) contacts that must be controlled to form good SAM-based devices. In this Account, we first trace the evolution of SAM-based electronic devices and rationalize their operation using energy level diagrams. We describe the measurement of device properties using near edge X-ray absorption fine structure spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy complemented by molecular dynamics and electronic structure calculations together with large numbers of electrical measurements. We discuss how data obtained from these combined experimental/simulation codesign studies demonstrate control over the supramolecular and electronic structure of the devices, tuning odd-even effects to optimize inherent packing tendencies of the molecules in order to minimize leakage currents

  5. PIT Coating Requirements Analysis

    SciTech Connect

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  6. Nanostructured Protective Coatings

    DTIC Science & Technology

    2006-01-01

    potential superior wear resistance properties. The Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of...understanding of PVD parameters, depositing coatings on practical substrates such as the Ti6Al4V used for turbine blades , and developing a versatile...Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of three entities (Pennsylvania State University

  7. Spin coating of electrolytes

    DOEpatents

    Stetter, Joseph R.; Maclay, G. Jordan

    1989-01-01

    Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.

  8. Ceramic with zircon coating

    NASA Technical Reports Server (NTRS)

    Wang, Hongyu (Inventor)

    2003-01-01

    An article comprises a silicon-containing substrate and a zircon coating. The article can comprise a silicon carbide/silicon (SiC/Si) substrate, a zircon (ZrSiO.sub.4) intermediate coating and an external environmental/thermal barrier coating.

  9. Commercial Fastener Coatings Doerken

    DTIC Science & Technology

    2010-06-01

    Phosphating* *partly recommended Dip Spinning Dipping Spraying Spin coating Conveyor oven box oven Inductive drying Pretreatment Coating Preheating...Curing Cooling Application Techniques - Dip Spin Coating Gurtbnd Cross BarTranspo" Band beiCifteiE Vo12one Vent llated Pre .Zone Cros~ Bar T ransrt

  10. Tracking the MSL-SAM methane detection source location Through Mars Regional Atmospheric Modeling System (MRAMS)

    NASA Astrophysics Data System (ADS)

    Pla-García, Jorge

    2016-04-01

    1. Introduction: The putative in situ detection of methane by Sample Analysis at Mars (SAM) instrument suite on Curiosi-ty at Gale crater has garnered significant attention because of the potential implications for the presence of geological methane sources or indigenous Martian organisms [1, 2]. SAM reported detection of back-ground levels of atmospheric methane of mean value 0.69±0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). Additionally, in four sequential measurements spanning a 60-sol period, SAM observed elevated levels of methane of 7.2±2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source. There are many major unresolved questions regard-ing this detection: 1) What are the potential sources of the methane release? 2) What causes the rapid decrease in concentration? and 3) Where is the re-lease location? 4) How spatially extensive is the re-lease? 5) For how long is CH4 released? Regarding the first question, the source of methane, is so far not identified. It could be related with geo-logical process like methane release from clathrates [3], serpentinisation [4] and volcanism [5]; or due to biological activity from methanogenesis [6]. To answer the second question, the rapid decrease in concentration, it is important to note that the photo-chemical lifetime of methane is of order 100 years, much longer than the atmospheric mixing time scale, and thus the gas should tend to be well mixed except near a source or shortly after an episodic release. The observed spike of 7 ppb from the background of <1 ppb, and then the rapid return to the background lev-el could be due to a sink (destruction) or due to at-mospheric mixing. A wind mediated erosion process of ordinary quartz crystals was proposed to produce activated quartz grains, which sequester methane by forming covalent Si-C bonds. If this process is op-erational on Mars today, which some recent prelimi-nary studies on

  11. Identification of an S-adenosylmethionine (SAM) dependent arsenic methyltransferase in Danio rerio

    SciTech Connect

    Hamdi, Mohamad; Yoshinaga, Masafumi; Packianathan, Charles; Qin, Jie; Hallauer, Janell; McDermott, Joseph R.; Yang, Hung-Chi; Tsai, Kan-Jen; Liu, Zijuan

    2012-07-15

    Arsenic methylation is an important cellular metabolic process that modulates arsenic toxicity and carcinogenicity. Biomethylation of arsenic produces a series of mono-, di- and tri-methylated arsenic metabolites that can be detected in tissues and excretions. Here we report that zebrafish exposed to arsenite (As{sup III}) produces organic arsenicals, including MMA{sup III}, MMA{sup V} and DMA{sup V} with characteristic tissue ratios, demonstrating that an arsenic methylation pathway exists in zebrafish. In mammals, cellular inorganic arsenic is methylated by a SAM-dependent arsenic methyltransferase, AS3MT. A zebrafish arsenic methyltransferase homolog, As3mt, was identified by sequence alignment. Western blotting analysis showed that As3mt was universally expressed in zebrafish tissues. Prominent expression in liver and intestine correlated with methylated arsenic metabolites detected in those tissues. As3mt was expressed in and purified from Escherichia coli for in vitro functional studies. Our results demonstrated that As3mt methylated As{sup III} to DMA{sup V} as an end product and produced MMA{sup III} and MMA{sup V} as intermediates. The activity of As3mt was inhibited by elevated concentrations of the substrate As{sup III} as well as the metalloid selenite, which is a well-known antagonistic micronutrient of arsenic toxicity. The activity As3mt was abolished by substitution of either Cys160 or Cys210, which corresponds to conserved cysteine residues in AS3MT homologs, suggesting that they are involved in catalysis. Expression in zebrafish of an enzyme that has a similar function to human and rodent orthologs in catalyzing intracellular arsenic biomethylation validates the applicability of zebrafish as a valuable vertebrate model for understanding arsenic-associated diseases in humans. -- Highlights: ► Zebrafish methylated As{sup III} to MMA{sup III}, MMA{sup V} and DMA{sup V}. ► A zebrafish arsenic methyltransferase (As3mt) was purified in E. coli.

  12. Influence of Oxychlorine Phases During the Pyrolysis of Organic Molecules: Implications for the Quest of Organics on Mars with the SAM Experiment Onboard the Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Millan, M.; Szopa, C.; Buch, A.; Belmahdi, I.; Glavin, D. P.; Freissinet, C.; Eigenbrode, J. L.; Archer, P. D., Jr,; Sutter, B.; Mahaffy, P.

    2017-01-01

    One among the main objectives of the Sample Analysis at Mars (SAM) experiment is the in situ molecular analysis of gases evolving from solid samples heated up to approximately 850 degrees Centigrade, and collected by Curiosity on Mars surface/sub-surface in Gale crater. With this aim, SAM uses a gas-chromatograph coupled to a quadrupole mass spectrometer (GC-QMS) devoted to separate, detect and identify both volatile inorganic and organic compounds. SAM detected chlorinated organic molecules produced in evolved gas analysis (EGA) experiments. Several of these were also detected by the Viking experiments in 1976. SAM also detected oxychlorine compounds that were present at the Phoenix landing site. The oxychlorines may be prevelant over much of the martian surface. The C1 to C3 aliphatic chlorohydrocarbons (chloromethane and di- and trichloromethane) detected by SAM were attributed to reaction products occurring between the oxychlorines phases and the organic compounds coming from SAM instrument background. But SAM also showed the presence of a large excess of chlorobenzene and C2 to C4 dichloroalkanes among the volatile species released by the Cumberland sample of the Sheepbed mudstone. For the first time in the history of the Mars exploration, this proved the presence of Mars indigenous organic material at the Mars' surface. However, the identification of the precursor organic compounds of these chlorohydrocarbons is difficult due to the complexity of the reactions occurring during the sample pyrolysis. Laboratory pyrolysis experiments have demonstrated that oxychlorines phases such as perchlorates and chlorates, decomposed into dioxygen and volatile chlorine bearing molecules (HCl and/or Cl2) during the pyrolysis. These chemical species can then react with the organic molecules present in the martian solid samples through oxidation, chlorination and oxychlorination processes.

  13. The Investigation of Perchlorate/Iron Phase Mixtures as A Possible Source of Oxygen Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Heil, E.; Morris, R. V.; Archer, P. D.; Ming, D. W.; Niles, P. B.; Eigenbrode, J. L.; Franz, H.; Freissinet C.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P.; Martin-Torres, F. Javier; Navarro-Gonzalez, R.; Paz-Zorzano, Maria; Stern, J. C.; McKay, C. P.

    2015-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detected O2 and HCl gas releases from the Rocknest (RN) eolian bedform and the John Klein (JK) and Cumberland (CB) drill hole materials in Gale Crater. Chlorinated hydrocarbons have also been detected by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS). These detections along with the detection of perchlorate (ClO4-) by the Mars Phoenix Lander's Wet Chemistry Laboratory (WCL) suggesting perchlorate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of individual per-chlorates has yet to provide an unequivocal temperature match to the SAM O2 and HCl release data. These detections along with the detection of perchlorate (ClO4-) by the Mars Phoenix Lander's Wet Chemistry Laboratory suggested perchlorate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of pure perchlorates has yet to provide an unequivocal temperature match to the SAM O2 and HCl release data. Analog laboratory analysis of iron mineralogy detected in Gale materials that was physically mixed with Ca- and Mg-perchlorate has been shown to catalyze lower O2 release temperatures and approach some SAM O2 release data. Instead of physical mixtures used in previous work, the work presented here utilized perchlorate solutions added to Fe phases. This technique allowed for perchlorate to come in closer contact with the Fe-phase and may more closely mimic Mars conditions where humidity can increase enough to cause deliquescence of the highly hygroscopic perchlorate phases. The objective of this work is to: 1) Utilize a laboratory SAM analog instrument to evaluate the O2 release temperatures from Mg- and Ca-perchlorates solutions applied to Fephases detetected in Gale Crate; and 2) Determine if perchlorate solutions can provide improved matches with the SAM O2 temperature release profiles.

  14. Thermal and Evolved Gas Analysis of Calcite Under Reduced Operating Pressures: Implications for the 2011 MSL Sample Analysis at Mars (SAM) Instrument

    NASA Technical Reports Server (NTRS)

    Lauer, H. V. Jr.; Ming, D. W.; Sutter, B.; Mahaffy, P. R.

    2010-01-01

    The Mars Science Laboratory (MSL) is scheduled for launch in 2011. The science objectives for MSL are to assess the past or present biological potential, to characterize the geology, and to investigate other planetary processes that influence habitability at the landing site. The Sample Analysis at Mars (SAM) is a key instrument on the MSL payload that will explore the potential habitability at the landing site [1]. In addition to searching for organic compounds, SAM will have the capability to characterized evolved gases as a function of increasing temperature and provide information on the mineralogy of volatile-bearing phases such as carbonates, sulfates, phyllosilicates, and Fe-oxyhydroxides. The operating conditions in SAM ovens will be maintained at 30 mb pressure with a He carrier gas flowing at 1 sccm. We have previously characterized the thermal and evolved gas behaviors of volatile-bearing species under reduced pressure conditions that simulated operating conditions of the Thermal and Evolved Gas Analyzer (TEGA) that was onboard the 2007 Mars Phoenix Scout Mission [e.g., 2-8]. TEGA ovens operated at 12 mb pressure with a N2 carrier gas flowing at 0.04 sccm. Another key difference between SAM and TEGA is that TEGA was able to perform differential scanning calorimetry whereas SAM only has a pyrolysis oven. The operating conditions for TEGA and SAM have several key parameter differences including operating pressure (12 vs 30 mb), carrier gas (N2 vs. He), and carrier gas flow rate (0.04 vs 1 sccm). The objectives of this study are to characterize the thermal and evolved gas analysis of calcite under SAM operating conditions and then compare it to calcite thermal and evolved gas analysis under TEGA operating conditions.

  15. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  16. Antibacterial polymer coatings.

    SciTech Connect

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  17. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S.; Leibert, C. H. (Inventor)

    1977-01-01

    A coating system which contains a bond coating and a thermal barrier coating is applied to metal surfaces such as turbine blades and provides both low thermal conductivity and improved adherence when exposed to high temperature gases or liquids. The bond coating contains NiCrAlY and the thermal barrier coating contains a reflective oxide. The reflective oxides ZrO2-Y2O3 and ZrO2-MgO have demonstrated significant utility in high temperature turbine applications.

  18. Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    1993-01-01

    In order to reduce heat transfer between a hot gas heat source and a metallic engine component, a thermal insulating layer of material is placed between them. This thermal barrier coating is applied by plasma spray processing the thin films. The coating has been successfully employed in aerospace applications for many years. Lewis Research Center, a leader in the development engine components coating technology, has assisted Caterpillar, Inc. in applying ceramic thermal barrier coatings on engines. Because these large engines use heavy fuels containing vanadium, engine valve life is sharply decreased. The barrier coating controls temperatures, extends valve life and reduces operating cost. Additional applications are currently under development.

  19. Biosynthesis of the [FeFe] Hydrogenase H Cluster: A Central Role for the Radical SAM Enzyme HydG.

    PubMed

    Suess, Daniel L M; Kuchenreuther, Jon M; De La Paz, Liliana; Swartz, James R; Britt, R David

    2016-01-19

    Hydrogenase enzymes catalyze the rapid and reversible interconversion of H2 with protons and electrons. The active site of the [FeFe] hydrogenase is the H cluster, which consists of a [4Fe-4S]H subcluster linked to an organometallic [2Fe]H subcluster. Understanding the biosynthesis and catalytic mechanism of this structurally unusual active site will aid in the development of synthetic and biological hydrogenase catalysts for applications in solar fuel generation. The [2Fe]H subcluster is synthesized and inserted by three maturase enzymes-HydE, HydF, and HydG-in a complex process that involves inorganic, organometallic, and organic radical chemistry. HydG is a member of the radical S-adenosyl-l-methionine (SAM) family of enzymes and is thought to play a prominent role in [2Fe]H subcluster biosynthesis by converting inorganic Fe(2+), l-cysteine (Cys), and l-tyrosine (Tyr) into an organometallic [(Cys)Fe(CO)2(CN)](-) intermediate that is eventually incorporated into the [2Fe]H subcluster. In this Forum Article, the mechanism of [2Fe]H subcluster biosynthesis is discussed with a focus on how this key [(Cys)Fe(CO)2(CN)](-) species is formed. Particular attention is given to the initial metallocluster composition of HydG, the modes of substrate binding (Fe(2+), Cys, Tyr, and SAM), the mechanism of SAM-mediated Tyr cleavage to CO and CN(-), and the identification of the final organometallic products of the reaction.

  20. Covalent Intermediate in the Catalytic Mechanism of the Radical SAM Methyl Synthase RlmN Trapped by Mutagenesis

    PubMed Central

    McCusker, Kevin P.; Medzihradszky, Katalin F.; Shiver, Anthony L.; Nichols, Robert J.; Yan, Feng; Maltby, David A.; Gross, Carol A.; Fujimori, Danica Galonić

    2012-01-01

    The posttranscriptional modification of ribosomal RNA (rRNA) modulates ribosomal function and confers resistance to antibiotics targeted to the ribosome. The radical SAM (S-adenosyl-L-methionine) methyl synthases, RlmN and Cfr, both methylate A2503 within the peptidyl transferase center (PTC) of prokaryotic ribosomes, yielding 2-methyl- and 8-methyl-adenosine, respectively. The C2 and C8 positions of adenosine are unusual methylation substrates due to their electrophilicity. To accomplish this reaction, RlmN and Cfr proceed by a shared radical-mediated mechanism. However, in addition to the radical SAM CX3CX2C motif, both RlmN and Cfr contain two conserved cysteine residues required for in vivo function. These conserved cysteine residues are putatively involved in a covalent intermediate employed by RlmN and Cfr in order to achieve this challenging transformation. Currently, there is no direct evidence for this proposed covalent intermediate. We have further investigated the roles of these conserved cysteines in the mechanism of RlmN. Cysteine 118 mutants of RlmN are unable to resolve the covalent intermediate, either in vivo or in vitro, enabling us to isolate and characterize this intermediate. Additionally, tandem mass spectrometric analyses of mutant RlmN reveal a methylene-linked adenosine modification at cysteine 355. Employing deuterium-labeled SAM and RNA substrates in vitro has allowed us to further elucidate the mechanism of formation of this intermediate. Together, these experiments provide compelling evidence for the formation of a covalent intermediate species formed between RlmN and its rRNA substrate and the roles of the conserved cysteine residues in catalysis. PMID:23088750

  1. Potential precursor compounds for chlorohydrocarbons detected in Gale Crater, Mars, by the SAM instrument suite on the Curiosity Rover

    NASA Astrophysics Data System (ADS)

    Miller, Kristen E.; Eigenbrode, Jennifer L.; Freissinet, Caroline; Glavin, Daniel P.; Kotrc, Benjamin; Francois, Pascaline; Summons, Roger E.

    2016-03-01

    The detection of chlorinated organic compounds in near-surface sedimentary rocks by the Sample Analysis at Mars (SAM) instrument suite aboard the Mars Science Laboratory Curiosity rover represents an important step toward characterizing habitable environments on Mars. However, this discovery also raises questions about the identity and source of their precursor compounds and the processes by which they become chlorinated. Here we present the results of analog experiments, conducted under conditions similar to SAM gas chromatography-mass spectrometry analyses, in which we pyrolyzed potential precursor compounds in the presence of various Cl salts and Fe oxides that have been identified in Martian sediments. While chloromethanes could not be unambiguously identified, 1,2-dichloropropane (1,2-DCP), which is one of the chlorinated compounds identified in SAM data, is formed from the chlorination of aliphatic precursors. Additionally, propanol produced more 1,2-DCP than nonfunctionalized aliphatics such as propane or hexanes. Chlorinated benzenes ranging from chlorobenzene to hexachlorobenzene were identified in experiments with benzene carboxylic acids but not with benzene or toluene. Lastly, the distribution of chlorinated benzenes depended on both the substrate species and the nature and concentration of the Cl salt. Ca and Mg perchlorate, both of which release O2 in addition to Cl2 and HCl upon pyrolysis, formed less chlorobenzene relative to the sum of all chlorinated benzenes than in experiments with ferric chloride. FeCl3, a Lewis acid, catalyzes chlorination but does not aid combustion. Accordingly, both the precursor chemistry and sample mineralogy exert important controls on the distribution of chlorinated organics.

  2. Bacillus subtilis Spore Coat

    PubMed Central

    Driks, Adam

    1999-01-01

    In response to starvation, bacilli and clostridia undergo a specialized program of development that results in the production of a highly resistant dormant cell type known as the spore. A proteinacious shell, called the coat, encases the spore and plays a major role in spore survival. The coat is composed of over 25 polypeptide species, organized into several morphologically distinct layers. The mechanisms that guide coat assembly have been largely unknown until recently. We now know that proper formation of the coat relies on the genetic program that guides the synthesis of spore components during development as well as on morphogenetic proteins dedicated to coat assembly. Over 20 structural and morphogenetic genes have been cloned. In this review, we consider the contributions of the known coat and morphogenetic proteins to coat function and assembly. We present a model that describes how morphogenetic proteins direct coat assembly to the specific subcellular site of the nascent spore surface and how they establish the coat layers. We also discuss the importance of posttranslational processing of coat proteins in coat morphogenesis. Finally, we review some of the major outstanding questions in the field. PMID:10066829

  3. Coatings for directional eutectics

    NASA Technical Reports Server (NTRS)

    Rairden, J. R.; Jackson, M. R.

    1976-01-01

    Significant advances have been made in the development of an environmentally stable coating for a very high strength, directionally solidified eutectic alloy designated NiTaC-13. Three duplex (two-layer) coatings survived 3,000 hours on a cyclic oxidation test (1,100 C to 90 C). These coatings were fabricated by first depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam heated source, followed by depositing an aluminizing overlayer. The alloy after exposure with these coatings was denuded of carbide fibers at the substrate/coating interface. It was demonstrated that TaC fiber denudation can be greatly retarded by applying a carbon-bearing coating. The coating was applied by thermal spraying followed by aluminization. Specimens coated with NiCrAlCY+Al survived over 2,000 hours in the cyclic oxidation test with essentially no TaC denudation. Coating ductility was studied for coated and heat-treated bars, and stress rupture life at 871 C and 1,100 C was determined for coated and cycled bars.

  4. Binding of the C-terminal sterile alpha motif (SAM) domain of human p73 to lipid membranes.

    PubMed

    Barrera, Francisco N; Poveda, José A; González-Ros, José M; Neira, José L

    2003-11-21

    The alpha splice variant of p73 (p73alpha), a homologue of the tumor suppressor p53, has close to its C terminus a sterile alpha motif (SAM), SAMp73, that is thought to be involved in protein-protein interactions. Here, we report the lipid binding properties of this domain. Binding was assayed against zwitterionic (phosphatidylcholine) and anionic (phosphatidic acid) lipids and was studied by different biophysical techniques, namely, circular dichroism and fluorescence spectroscopies and differential scanning calorimetry. These techniques unambiguously indicate that SAMp73 binds to lipids. The binding involves protein surface attachment and partial membrane penetration, accompanied by changes in SAMp73 structure.

  5. Utilization of Landsat multispectral data in geobotanical investigations - The location of ironstone gravel in the Sam Houston National Forest, Texas

    NASA Technical Reports Server (NTRS)

    Cibula, William G.; Lucas, Wilmuth

    1990-01-01

    The location of ironstone gravel deposits by remote sensing (using Landsat MSS frames) over a heavily vegetated terrain is demonstrated. It is suggested that the spectral class exhibited on an analyzed Landsat frame (acquired during a protracted drought period) relates to water stressed regions within the upland pine forest type as a result of the near-surface geology of the areas where ironstone gravel is present. It is also suggested that the presence of both the ironstone aggregate and the associated plinthite hardpan layer may be responsible for the absence of longleaf pine on these sites of the Sam Houston National Forest, as compared to similar sites a few km away.

  6. Mathematical Development of the Spill Assessment Model (SAM) for Hydrazine and Similar Acting Materials in Water Bodies.

    DTIC Science & Technology

    1980-02-01

    AFESC/ESL-TR-80-07 NL Aa./ E R HEE//lllnlllllnlhl IIIIIIIIIIIIIIffllfllf IIIIIIIIIIIIII IIIIIIIIIIIIIIh EIEIIEIIEEEEEE iWii 1 1 . 10 ;s *DI,*lu I,[L...MIR1 RESOLUTIO40 11111H2. II.I25 11f1 1 01 . MICROCOPY RESOLUTION TEST CHART L fESL-TR-80-07 MATHEMATICAL DEVELOPMENT OF THE SPILL ASSESSMENT MODEL (SAM...FORM 1 , I 12. GOVT ACCESSION NO. 3. PIENTiS CATALOG NUMBER ESLVTR-8p-T -/ / 4. TITLE (and Subtitle) . - .OVERED & ,)THEMATICAL.EVELOPMENT OF THESPILL

  7. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  8. Coated Aerogel Beads

    NASA Technical Reports Server (NTRS)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  9. Search for nitrates on Mars by the Sample Analysis at Mars (SAM) Instrument

    NASA Astrophysics Data System (ADS)

    Navarro-Gonzalez, Rafael

    One of the main goals of the Mars Science Laboratory is to determine whether the planet ever had environmental conditions capable of supporting microbial life. Nitrogen is a fundamental element for life, and is present in structural (e.g., proteins), catalytic (e.g., enzymes and ribozymes), energy transfer (e.g., ATP) and information storage (RNA and DNA) bio-molecules. Planetary models suggest that nitrogen was abundant in the early Martian atmosphere as dinitrogen (N _{2}). However, a fraction of N _{2} has been lost to space by sputtering and photochemical processes [1, 2], impact erosion [3], and chemical oxidation to nitrates [4, 5]. Nitrates produced early in Mars’ history by photochemistry may later decompose back into N _{2} by the current impact flux [6]. It is estimated that the Martian surface could contain soil nitrates at levels of 0.3 wt.% N, if mixed homogenously [6], or a layer of pure NaNO _{3} of about 3 m thickness [5] distributed globally. Nitrates are a fundamental source for nitrogen for terrestrial microorganisms. Therefore, the detection of soil nitrates is important to assess habitability in the Martian environment. The only previous attempt to search for soil nitrates was by TEGA and the MECA WCL on the Phoenix mission but no evolved N-containing species were detected [7]. Nitrates have been tentatively identified in two Martian meteorites: Nakhla [8] and EETA79001 [9]. SAM is capable of detecting nitrates by their thermal decomposition into nitric oxide, NO. SAM analyzed samples from Rocknest soil and two drill holes located at John Klein (JK) and Cumberland (CB) mudstones in the Sheepbed member of the Yellowknife Bay formation in Gale Crater. There appear to be several peaks associated with the release of m/z 30 in the temperature range from 150(°) °C to 600(°) °C. M/z 30 can be attributed to nitric oxide; however, other possible chemical interferences may be present, such as ethane (C _{2}H _{6}), formaldehyde (HCHO), diazene (N

  10. Search for nitrates on Mars by the Sample Analysis at Mars (SAM) Instrument

    NASA Astrophysics Data System (ADS)

    Navarro-Gonzalez, Rafael; Stern, Jennifer; Freissinet, Caroline; Franz, Heather; McKay, Christopher; Coll, Patrice; Sutter, Brad; Archer, Doug; McAdam, Amy; Cabane, Michel; Ming, Douglas; Glavin, Daniel; Eigenbrode, Jennifer; Leshin, Laurie; Wong, Michael; Atreya, Sushil; Wray, James; Steele, Andrew; Buch, Arnaud; Prats, Benito

    2014-05-01

    One of the main goals of the Mars Science Laboratory is to determine whether the planet ever had environmental conditions capable of supporting microbial life. Nitrogen is a fundamental element for life, and is present in structural (e.g., proteins), catalytic (e.g., enzymes and ribozymes), energy transfer (e.g., ATP) and information storage (RNA and DNA) bio-molecules. Planetary models suggest that nitrogen was abundant in the early Martian atmosphere as dinitrogen (N2). However, a fraction of N2 has been lost to space by sputtering and photochemical processes [1, 2], impact erosion [3], and chemical oxidation to nitrates [4, 5]. Nitrates produced early in Mars' history by photochemistry may later decompose back into N2 by the current impact flux [6]. It is estimated that the Martian surface could contain soil nitrates at levels of 0.3 wt.% N, if mixed homogenously [6], or a layer of pure NaNO3 of about 3 m thickness [5] distributed globally. Nitrates are a fundamental source for nitrogen for terrestrial microorganisms. Therefore, the detection of soil nitrates is important to assess habitability in the Martian environment. The only previous attempt to search for soil nitrates was by TEGA and the MECA WCL on the Phoenix mission but no evolved N-containing species were detected [7]. Nitrates have been tentatively identified in two Martian meteorites: Nakhla [8] and EETA79001 [9]. SAM is capable of detecting nitrates by their thermal decomposition into nitric oxide, NO. SAM analyzed samples from Rocknest soil and two drill holes located at John Klein (JK) and Cumberland (CB) mudstones in the Sheepbed member of the Yellowknife Bay formation in Gale Crater. There appear to be several peaks associated with the release of m/z 30 in the temperature range from 150° C to 600° C. m/z 30 can be attributed to nitric oxide; however, other possible chemical interferences may be present and are assessed. The origin of nitric oxide is discussed and its thermal evolution is

  11. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  12. Insights into the structure, function and evolution of the radical-SAM 23S rRNA methyltransferase Cfr that confers antibiotic resistance in bacteria

    PubMed Central

    Kaminska, Katarzyna H.; Purta, Elzbieta; Hansen, Lykke H.; Bujnicki, Janusz M.; Vester, Birte; Long, Katherine S.

    2010-01-01

    The Cfr methyltransferase confers combined resistance to five classes of antibiotics that bind to the peptidyl tranferase center of bacterial ribosomes by catalyzing methylation of the C-8 position of 23S rRNA nucleotide A2503. The same nucleotide is targeted by the housekeeping methyltransferase RlmN that methylates the C-2 position. Database searches with the Cfr sequence have revealed a large group of closely related sequences from all domains of life that contain the conserved CX3CX2C motif characteristic of radical S-adenosyl-l-methionine (SAM) enzymes. Phylogenetic analysis of the Cfr/RlmN family suggests that the RlmN subfamily is likely the ancestral form, whereas the Cfr subfamily arose via duplication and horizontal gene transfer. A structural model of Cfr has been calculated and used as a guide for alanine mutagenesis studies that corroborate the model-based predictions of a 4Fe–4S cluster, a SAM molecule coordinated to the iron–sulfur cluster (SAM1) and a SAM molecule that is the putative methyl group donor (SAM2). All mutations at predicted functional sites affect Cfr activity significantly as assayed by antibiotic susceptibility testing and primer extension analysis. The investigation has identified essential amino acids and Cfr variants with altered reaction mechanisms and represents a first step towards understanding the structural basis of Cfr activity. PMID:20007606

  13. Isotopic Composition of Carbon Dioxide Released from Confidence Hills Sediment as Measured by the Sample Analysis at Mars (SAM) Quadrupole Mass Spectrometer

    NASA Technical Reports Server (NTRS)

    Franz, H. B.; Mahaffy, P. R.; Stern, J.; Archer, P., Jr.; Conrad, P.; Eigenbrode, J.; Freissinet, C.; Glavin, D.; Grotzinger, J. P.; Jones, J.; Ming, D.; McAdam, A.; Morris, R.; Navarro-Gozalez, R.; Owen, T.; Steele, A.; Summons, R.; Sutter, B.; Webster, C. R.

    2015-01-01

    In October 2014, the Mars Science Laboratory (MSL) "Curiosity" rover drilled into the sediment at the base of Mount Sharp in a location namsed Cionfidence Hills (CH). CH marked the fifth sample pocessed by the Sample Analysis at Mars (SAM) instrument suite since Curiosity arrived in Gale Crater, with previous analyses performed at Rocknest (RN), John Klein (JK), Cumberland (CB), and Windjana (WJ). Evolved gas analysis (EGA) of all samples has indicated H2O as well as O-, C- and S-bearing phases in the samples, often at abundances that would be below the detection limit of the CheMin instrument. By examining the temperatures at which gases are evolved from samples, SAM EGA data can help provide clues to the mineralogy of volatile-bearing phases when their identities are unclear to CheMin. SAM may also detect gases evolved from amorphous material in solid samples, which is not suitable for analysis by CheMin. Finally, the isotopic composition of these gases may suggest possible formation scenarios and relationships between phases. We will discuss C isotope ratios of CO2 evolved from the CH sample as measured with SAM's quadrupole mass spectrometer (QMS) and draw comparisons to samples previously analyzed by SAM.

  14. A Standard Analysis Method (SAM) for the automated analysis of polychlorinated biphenyls (PCBs) in soils using the chemical analysis automation (CAA) paradigm: Validation and performance

    SciTech Connect

    Rzeszutko, C.; Johnson, C.R.; Monagle, M.; Klatt, L.N.

    1997-11-01

    The Chemical Analysis Automation (CAA) program is developing a standardized modular automation strategy for chemical analysis. In this automation concept, analytical chemistry is performed with modular building blocks that correspond to individual elements of the steps in the analytical process. With a standardized set of behaviors and interactions, these blocks can be assembled in a plug-and-play manner into a complete analysis system. These building blocks, which are referred to as Standard laboratory Modules (SLM), interface to a host control system that orchestrates the entire analytical process, from sample preparation through data interpretation. The integrated system is called a Standard Analysis Method (SAM). A SAM for the automated determination of polychlorinated biphenyls (PCBs) in soils, assembled in a mobile laboratory, is undergoing extensive testing and validation. The SAM consists of the following SLMs: a four-channel Soxhlet extractor, a high-volume concentration, a column clean-up, a gas chromatography, a PCB data-interpretation module, a robot, and a human-computer interface. The SAM is configured to meet the requirements specified in the US Environmental Protection Agency`s (EPA) SW-846 methods 3541/3620A/8082 for the analysis of PCBs in soils. The PCB SAM will be described along with the developmental test plan. Performance data obtained during developmental testing will also be discussed.

  15. Replicase, excisionase, and integrase genes of the Streptomyces element pSAM2 constitute an operon positively regulated by the pra gene.

    PubMed

    Sezonov, G; Duchêne, A M; Friedmann, A; Guérineau, M; Pernodet, J L

    1998-06-01

    pSAM2 is a site-specific integrative element from Streptomyces ambofaciens. The pra gene described earlier as an activator of pSAM2 replication is shown here to be also involved in the activation of its integration and excision. This was evidenced with derivatives of pSAM2 mutant B3 in which the pra gene was placed under the control of the inducible tipAp promoter. Transformation of Streptomyces lividans by these derivatives was efficient only when pra expression was induced, indicating its involvement in pSAM2 integration activation. Once established, these constructions remained integrated in the chromosome under noninduced conditions. Activation of the pra expression provoked strong activation of their excision, leading to the appearance of free forms. The results of functional, transcriptional, and sequence analyses allowed to conclude that the three genes repSA, xis, and int coding for the pSAM2 replicase, excisionase, and integrase, respectively, constitute an operon directly or indirectly activated by pra.

  16. Replicase, Excisionase, and Integrase Genes of the Streptomyces Element pSAM2 Constitute an Operon Positively Regulated by the pra Gene

    PubMed Central

    Sezonov, Guennadi; Duchêne, Anne-Marie; Friedmann, Annick; Guérineau, Michel; Pernodet, Jean-Luc

    1998-01-01

    pSAM2 is a site-specific integrative element from Streptomyces ambofaciens. The pra gene described earlier as an activator of pSAM2 replication is shown here to be also involved in the activation of its integration and excision. This was evidenced with derivatives of pSAM2 mutant B3 in which the pra gene was placed under the control of the inducible tipAp promoter. Transformation of Streptomyces lividans by these derivatives was efficient only when pra expression was induced, indicating its involvement in pSAM2 integration activation. Once established, these constructions remained integrated in the chromosome under noninduced conditions. Activation of the pra expression provoked strong activation of their excision, leading to the appearance of free forms. The results of functional, transcriptional, and sequence analyses allowed to conclude that the three genes repSA, xis, and int coding for the pSAM2 replicase, excisionase, and integrase, respectively, constitute an operon directly or indirectly activated by pra. PMID:9620953

  17. Molecular tilt-dependent and tyrosine-enhanced electron transfer across ITO/SAM/[DPPC-Au NP-Tyrosine] Janus nanoparticle junction

    NASA Astrophysics Data System (ADS)

    Sarangi, Nirod Kumar; Patnaik, Archita

    2016-09-01

    Enhanced interfacial electron transfer (ET) across the otherwise insulating indium tin oxide/alkanethiol self-assembled monolayer (SAM)/redox molecule junction was accomplished when a Janus gold nanoparticle (JNP) protected by bioinspired phosphatidylcholine (DPPC) lipid and tyrosine amino acid ligands was anchored on it. In addition to the most theoretical and experimental investigations on the distance-dependent ET across Metal-Organic SAM-Nanoparticle (NP) architectures, the current results succinctly illustrate molecular tilt angle of the SAM and the characteristic of JNP as key factors in expediting the ET rate via electron tunneling. In the absence of JNP, electron tunneling with a tunneling factor β = 1.1 Å-1 across the SAM was the rate-limiting step, evidenced from electrochemical impedance spectroscopy (EIS). The apparent electron transfer rate constant ( k app 0 ) for anchored SAM was enhanced by at least one order of magnitude than the DPPC-only protected nanoparticle, suggesting the potential role of tyrosine towards the enhanced ET. The asymmetric and biogenic nature of the construct sheds light on a potential bioelectronic device for novel electronic attributes.

  18. Tailored coatings for hardfacing

    SciTech Connect

    Dustoor, M.R.; Moskowitz, L.N.

    1984-01-01

    An update on Conforma Clad coatings, first presented at the 1982 National Powder Metallurgy Conference in Montreal, Canada, is presented. The major advantage is the ability to offer selective-area coatings in a wide range of thicknesses and material choices while retaining dimensional and edge control of the coating. Complex geometries can be coated with a high materials utilization and with coating properties tailored to the end application. Porosity and bond strength values can match or exceed those seen with the best commercially available thermal sprayed coatings. The ability of the process to balance abrasion resistance and toughness requirements for a specific wear mode, is illustrated by microstructural control of the size, shape and density of carbide particles contained in the coatings. Dry sand abrasive test data are provided on Conforma Clad coatings and competitive processes. Ongoing developments of non-furnace fusion techniques, such as laser cladding, are presented and the microstructures compared with those obtained with conventional coating processes. Commercial applications for these coatings are highlighted with some typical examples.

  19. Free energy calculations in electroactive self-assembled monolayers (SAMs): impact of the chain length on the redox reaction.

    PubMed

    Filippini, Gaelle; Israeli, Yael; Goujon, Florent; Limoges, Benoit; Bonal, Christine; Malfreyt, Patrice

    2011-10-13

    The free energy approach is used to study the effect of the relative chain length of the two constituents of electroactive self-assembled monolayers (SAMs) on gold. In this study, the ferrocene groups are exposed to the electrolyte solution. This situation is achieved by using shorter diluent alkanethiol chains. To this end, the mixed monolayers formed by the self-assembly of 11-ferrocenylundecanethiol and butanethiol FcC(11)S/C(4)S and of 6-ferrocenylhexanethiol and butanethiol FcC(6)S/C(4)S onto a gold surface are studied. Calculation of enthalpy and entropy differences are also performed using molecular simulations. Additionally, the electrochemical signatures of these systems are determined to allow a direct comparison with our calculations. The thermodynamic properties are discussed in terms of enthalpy and entropy changes. Two effects account for the thermodynamic behavior. The first one involves the ion pairing between the ferrocenium group and the perchlorate anion. The second one concerns the desolvation of the first hydration shell of the anions. Finally, this work is also completed with a microscopic description associated with an energy characterization of these SAMs as a function of the surface coverage under conditions close to experiments.

  20. The Sam68 nuclear body is composed of two RNase-sensitive substructures joined by the adaptor HNRNPL

    PubMed Central

    Yamashita, Seisuke; Goshima, Naoki

    2016-01-01

    The mammalian cell nucleus contains membraneless suborganelles referred to as nuclear bodies (NBs). Some NBs are formed with an architectural RNA (arcRNA) as the structural core. Here, we searched for new NBs that are built on unidentified arcRNAs by screening for ribonuclease (RNase)-sensitive NBs using 32,651 fluorescently tagged human cDNA clones. We identified 32 tagged proteins that required RNA for their localization in distinct nuclear foci. Among them, seven RNA-binding proteins commonly localized in the Sam68 nuclear body (SNB), which was disrupted by RNase treatment. Knockdown of each SNB protein revealed that SNBs are composed of two distinct RNase-sensitive substructures. One substructure is present as a distinct NB, termed the DBC1 body, in certain conditions, and the more dynamic substructure including Sam68 joins to form the intact SNB. HNRNPL acts as the adaptor to combine the two substructures and form the intact SNB through the interaction of two sets of RNA recognition motifs with the putative arcRNAs in the respective substructures. PMID:27377249

  1. Effects of the rate of releases from Sam Rayburn Reservoir on the Aeration Capacity of the Angelina River, eastern Texas

    USGS Publications Warehouse

    Rawson, Jack; Goss, Richard L.; Rathbun, Ira G.

    1980-01-01

    A three-phase study was conducted during July and August 1979 to determine the effects of varying release rates through the power-outlet works at Sam Rayburn Reservoir, eastern Texas, on aeration capacity of a 14-mile reach of the Angelina River below Sam Rayburn Dam. The dominant factors that affected the aeration capacity during the study time were time of travel and the dissolved-oxygen deficit of the releases. Aeration was low throughout the study but increased in response to increases in the dissolved-oxygen deficit and the duration of time that the releases were exposed to the atmosphere (time of travel). The average concentration of dissolved oxygen sustained by release of 8,800 cubic feet per second decreased from 5.0 milligrams per liter at a site near the power outlet to 4.8 milligrams per liter at a site about 14 miles downstream; the time of travel averaged about 8 hours. The average concentration of dissolved oxygen in flow sustained by releases of 2,200 cubic feet per second increased from 5.2 to 5.5 milligrams per liter; the time of travel averaged about 20 hours. (USGS)

  2. Mars Atmospheric Composition, Isotope Ratios and Seasonal Variations: Overview and Updates of the SAM Measurements at Gale Crater

    NASA Technical Reports Server (NTRS)

    Niles, Paul

    2014-01-01

    We will summarize the in situ measurements of atmospheric composition and the isotopic ratios of D/H in water, C-13/C-12, O-18/O-16, O-17 / O-16, and C-13 O-18 / C-12 O-16 in carbon dioxide, and Ar-38 / Ar-36, Kr-x / Kr-84, and N-15 / N-14 made in the martian atmosphere at Gale Crater from the Curiosity Rover using the Sample Analysis at Mars (SAM)'s Quadrupole Mass Spectrometer (QMS) and Tunable Laser Spectrometer (TLS). With data over 700 sols since the Curiosity landing, we will discuss evidence and implications for changes on seasonal and other timescales. We will also present results for continued methane and methane enrichment experiments over this time period. Comparison between our measurements in the modern atmosphere and those of martian meteorites like ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established approximately 4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.

  3. Structure-Based Design of a Novel SMYD3 Inhibitor that Bridges the SAM-and MEKK2-Binding Pockets.

    PubMed

    Van Aller, Glenn S; Graves, Alan P; Elkins, Patricia A; Bonnette, William G; McDevitt, Patrick J; Zappacosta, Francesca; Annan, Roland S; Dean, Tony W; Su, Dai-Shi; Carpenter, Christopher L; Mohammad, Helai P; Kruger, Ryan G

    2016-05-03

    SMYD3 is a lysine methyltransferase overexpressed in colorectal, breast, prostate, and hepatocellular tumors, and has been implicated as an oncogene in human malignancies. Methylation of MEKK2 by SMYD3 is important for regulation of the MEK/ERK pathway, suggesting the possibility of selectively targeting SMYD3 in RAS-driven cancers. Structural and kinetic characterization of SMYD3 was undertaken leading to a co-crystal structure of SMYD3 with a MEKK2-peptide substrate bound, and the observation that SMYD3 follows a partially processive mechanism. These insights allowed for the design of GSK2807, a potent and selective, SAM-competitive inhibitor of SMYD3 (Ki = 14 nM). A high-resolution crystal structure reveals that GSK2807 bridges the gap between the SAM-binding pocket and the substrate lysine tunnel of SMYD3. Taken together, our data demonstrate that small-molecule inhibitors of SMYD3 can be designed to prevent methylation of MEKK2 and these could have potential use as anticancer therapeutics.

  4. Suppression of HIV-1 Nef translation by Sam68 mutant-induced stress granules and nef mRNA sequestration

    PubMed Central

    Henao-Mejia, Jorge; Liu, Ying; Park, In-Woo; Zhang, Jizhong; Sanford, Jeremy; He, Johnny J.

    2009-01-01

    SUMMARY HIV-1 Nef plays important roles in HIV-1 replication and pathogenesis. It is translated from completely spliced HIV-1 RNA, its expression is inherently regulated at the levels of viral DNA transcription and RNA splicing. Here we show that Sam68 cytoplasmic mutants potently suppress Nef expression. The suppression requires Sam68 domain aa269-321 and is correlated with its ability to induce stress granules. In addition, the suppression is specific to Nef, and direct binding to nef mRNA 3′UTR confers the suppression specificity. Furthermore, nef mRNA is targeted to and enriched in these induced stress granules. Importantly, Nef suppression occurs in the context of HIV-1 infection of CD4+ T lymphocytes with little MHC I and CD4 down-regulation. Taken together, these results demonstrate that stress granule induction and nef mRNA sequestration account for this translational suppression of Nef expression and offers a new strategy for development of anti-HIV therapeutics to buttress our fight against HIV/AIDS. PMID:19150430

  5. Ultralow-Fouling Behavior of Biorecognition Coatings Based on Carboxy-Functional Brushes of Zwitterionic Homo- and Co-polymers in Blood Plasma: Functionalization Matters.

    PubMed

    Lísalová, Hana; Brynda, Eduard; Houska, Milan; Víšová, Ivana; Mrkvová, Kateřina; Song, Xue Chadtová; Gedeonová, Erika; Surman, František; Riedel, Tomáš; Pop-Georgievski, Ognen; Homola, Jiri

    2017-02-24

    Fouling from complex biological fluids such as blood plasma to biorecognition element (BRE)-functionalized coatings hampers the use of affinity biosensor technologies in medical diagnostics. Here we report the effects the molecular mechanisms involved in functionalization of low-fouling carboxy-functional coatings have on the BRE capacity and resistance to fouling from blood plasma. The specific mechanisms of EDC/NHS activation of carboxy-groups, BREs' attachment, and deactivation of residual activated groups on recently developed ultralow-fouling carboxybetaine polymer and copolymer brushes (pCB) as well as conventional carboxy-terminated oligo(ethylene glycol)-based alkanethiolate self-assembled monolayers (OEG-SAMs) are studied using the PM-IRRAS, XPS, and SPR methods. It is shown that the fouling resistance of BRE-functionalized pCB coatings is strongly influenced by a deactivation method affecting the ultralow-fouling molecular structure of the brush and the surface charges. It is revealed that, in contrast to free carboxy-group-terminated OEG-SAMs, only a partial deactivation of EDC/NHS-activated zwitterionic carboxy-groups by spontaneous hydrolysis is possible in the pCB brushes. The fouling resistance of activated/BRE-functionalized pCB is shown to be recovered only by covalent attachment of amino acid deactivation agents to residual activated carboxy-groups of pCB. The developed deactivation procedure is further combined with ultralow-fouling brushes of random copolymer carboxybetaine methacrylamide (CBMAA) and N-(2-hydroxypropyl) methacrylamide (HPMAA) with optimized CBMAA content (15%) providing a BRE-functionalized coating with superior fouling resistance over various carboxy-functional low-fouling coatings including homopolymer pCB brushes and OEG-SAMs. The biorecognition capabilities of pHPMAA-CBMAA(15%) are demonstrated via the sensitive label-free detection of a microRNA cancer biomarker (miR-16) in blood plasma.

  6. Coatings for graphite fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.

  7. Crystal structures of the armadillo repeat domain of adenomatous polyposis coli and its complex with the tyrosine-rich domain of Sam68.

    PubMed

    Morishita, Ella Czarina; Murayama, Kazutaka; Kato-Murayama, Miyuki; Ishizuka-Katsura, Yoshiko; Tomabechi, Yuri; Hayashi, Tomoatsu; Terada, Takaho; Handa, Noriko; Shirouzu, Mikako; Akiyama, Tetsu; Yokoyama, Shigeyuki

    2011-10-12

    Adenomatous polyposis coli (APC) is a tumor suppressor protein commonly mutated in colorectal tumors. APC plays important roles in Wnt signaling and other cellular processes. Here, we present the crystal structure of the armadillo repeat (Arm) domain of APC, which facilitates the binding of APC to various proteins. APC-Arm forms a superhelix with a positively charged groove. We also determined the structure of the complex of APC-Arm with the tyrosine-rich (YY) domain of the Src-associated in mitosis, 68 kDa protein (Sam68), which regulates TCF-1 alternative splicing. Sam68-YY forms numerous interactions with the residues on the groove and is thereby fixed in a bent conformation. We assessed the effects of mutations and phosphorylation on complex formation between APC-Arm and Sam68-YY. Structural comparisons revealed different modes of ligand recognition between the Arm domains of APC and other Arm-containing proteins.

  8. The Detection of Evolved Oxygen from the Rocknest Eolian Bedform Material by the Sample Analysis at Mars(SAM) instrument at the Mars Curiosity Landing Site

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Archer, D.; Ming, D.; Eigenbrode, J. L.; Franz, H.; Glavin, D. P.; McAdam, A.; Mahaffy, P.; Stern, J.; Navarro-Gonzalex, R.; McKay, C.

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detected an O2 gas release from the Rocknest eolain bedform (Fig. 1). The detection of perchlorate (ClO4-) by the Mars Phoenix Lander s Wet Chemistry Laboratory (WCL) [1] suggests that perchlorate is a possible candidate for evolved O2 release detected by SAM. The perchlorate would also serve as a source of chlorine in the chlorinated hydrocarbons detected by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS) [2,3]. Chlorates (ClO3-) [4,5] and/or superoxides [6] may also be sources of evolved O2 from the Rocknest materials. The work objectives are to 1) evaluate the O2 release temperatures from Rocknest materials, 2) compare these O2 release temperatures with a series of perchlorates and chlorates, and 3) evaluate superoxide O2- sources and possible perchlorate interactions with other Rocknest phases during QMS analysis.

  9. Functional Analysis of CP2-Like Domain and SAM-Like Domain in TFCP2L1, Novel Pluripotency Factor of Embryonic Stem Cells.

    PubMed

    Kim, Chang Min; Jang, Tae-Ho; Park, Hyun Ho

    2016-06-01

    TFCP2L1 is a transcription factor that facilitates establishment and maintenance of pluripotency in embryonic stem cells by forming a complex transcriptional network with other transcription factors (OCT4, SOX2, and NANOG). TFCP2L1 contains two distinct domains, the CP2-like domain at the N-terminus and the SAM-like domain at the C-terminus. In this study, we found that TFCP2L1 is hexamerized in solution via the C-terminal SAM-like domain. We also found that homo-oligomerization of SAM-like domain is dependent on the concentration of the proteins. Finally, we found that TFCP2L1 binds directly to DNA via the N-terminal CP2-like domain.

  10. Formation, Removal, and Reformation of Surface Coatings on Various Metal Oxide Surfaces Inspired by Mussel Adhesives.

    PubMed

    Kang, Taegon; Oh, Dongyeop X; Heo, Jinhwa; Lee, Han-Koo; Choy, Seunghwan; Hawker, Craig J; Hwang, Dong Soo

    2015-11-11

    Mussels survive by strongly attaching to a variety of different surfaces, primarily subsurface rocks composed of metal oxides, through the formation of coordinative interactions driven by protein-based catechol repeating units contained within their adhesive secretions. From a chemistry perspective, catechols are known to form strong and reversible complexes with metal ions or metal oxides, with the binding affinity being dependent on the nature of the metal ion. As a result, catechol binding with metal oxides is reversible and can be broken in the presence of a free metal ion with a higher stability constant. It is proposed to exploit this competitive exchange in the design of a new strategy for the formation, removal, and reformation of surface coatings and self-assembled monolayers (SAM) based on catechols as the adhesive unit. In this study, catechol-functionalized tri(ethylene oxide) (TEO) was synthesized as a removable and recoverable self-assembled monolayer (SAM) for use on oxides surfaces. Attachment and detachment of these catechol derivatives on a variety of surfaces was shown to be reversible and controllable by exploiting the high stability constant of catechol to soluble metal ions, such as Fe(III). This tunable assembly based on catechol binding to metal oxides represents a new concept for reformable coatings with applications in fields ranging from friction/wettability control to biomolecular sensing and antifouling.

  11. Electrospark deposition coatings

    NASA Astrophysics Data System (ADS)

    Sheely, W. F.

    1986-11-01

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life.

  12. Optical coating in space

    NASA Technical Reports Server (NTRS)

    Bunner, A. N.

    1983-01-01

    A technological appraisal of the steps required to approach the goal of in-situ optical coating, cleaning and re-coating the optical elements of a remote telescope in space is reported. Emphasis is placed on the high ultraviolet throughput that a telescope using bare aluminum mirrors would offer. A preliminary design is suggested for an Orbital Coating Laboratory to answer basic technical questions.

  13. Electrospark deposition coatings

    SciTech Connect

    Sheely, W.F.

    1986-11-19

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life. (DLC)

  14. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  15. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  16. Transfer functions of the conjugative integrating element pSAM2 from Streptomyces ambofaciens: characterization of a kil-kor system associated with transfer.

    PubMed

    Hagège, J; Pernodet, J L; Sezonov, G; Gerbaud, C; Friedmann, A; Guérineau, M

    1993-09-01

    pSAM2 is an 11-kb integrating element from Streptomyces ambofaciens. During matings, pSAM2 can be transferred at high frequency, forming pocks, which are zones of growth inhibition of the recipient strain. The nucleotide sequences of the regions involved in pSAM2 transfer, pock formation, and maintenance have been determined. Seven putative open reading frames with the codon usage typical of Streptomyces genes have been identified: traSA (306 amino acids [aa]), orf84 (84 aa), spdA (224 aa), spdB (58 aa), spdC (51 aa), spdD (104 aa), and korSA (259 aa). traSA is essential for pSAM2 intermycelial transfer and pock formation. It could encode a protein with similarities to the major transfer protein, Tra, of pIJ101. TraSA protein contains a possible nucleotide-binding sequence and a transmembrane segment. spdA, spdB, spdC, and spdD influence pock size and transfer efficiency and may be required for intramycelial transfer. A kil-kor system similar to that of pIJ101 is associated with pSAM2 transfer: the korSA (kil-override) gene product could control the expression of the traSA gene, which has lethal effects when unregulated (Kil phenotype). The KorSA protein resembles KorA of pIJ101 and repressor proteins belonging to the GntR family. Thus, the integrating element pSAM2 possesses for transfer general features of nonintegrating Streptomyces plasmids: different genes are involved in the different steps of the intermycelial and intramycelial transfer, and a kil-kor system is associated with transfer. However, some differences in the functional properties, organization, and sizes of the transfer genes compared with those of other Streptomyces plasmids have been found.

  17. The RNA-binding protein Sam68 regulates expression and transcription function of the androgen receptor splice variant AR-V7

    PubMed Central

    Stockley, Jacqueline; Markert, Elke; Zhou, Yan; Robson, Craig N.; Elliott, David J.; Lindberg, Johan; Leung, Hing Y.; Rajan, Prabhakar

    2015-01-01

    Castration-resistant (CR) prostate cancer (PCa) partly arises due to persistence of androgen receptor (AR) transcriptional activity in the absence of cognate ligand. An emerging mechanism underlying the CRPCa phenotype and predicting response to therapy is the expression of the constitutively-active AR-V7 splice variant generated by AR cryptic exon 3b inclusion. Here, we explore the role of the RNA-binding protein (RBP) Sam68 (encoded by KHDRBS1), which is over-expressed in clinical PCa, on AR-V7 expression and transcription function. Using a minigene reporter, we show that Sam68 controls expression of exon 3b resulting in an increase in endogenous AR-V7 mRNA and protein expression in RNA-binding-dependent manner. We identify a novel protein-protein interaction between Sam68 and AR-V7 mediated by a common domain shared with full-length AR, and observe these proteins in the cell nucleoplasm. Using a luciferase reporter, we demonstrate that Sam68 co-activates ligand-independent AR-V7 transcriptional activity in an RNA-binding-independent manner, and controls expression of the endogenous AR-V7-specific gene target UBE2C. Our data suggest that Sam68 has separable effects on the regulation of AR-V7 expression and transcriptional activity, through its RNA-binding capacity. Sam68 and other RBPs may control expression of AR-V7 and other splice variants as well as their downstream functions in CRPCa. PMID:26310125

  18. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, T.

    1997-02-18

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

  19. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, Toshifumi

    1997-01-01

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

  20. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A series of studies in which films and liquid spray-on materials were evaluated in the laboratory for transport aircraft external surface coatings are summarized. Elastomeric polyurethanes were found to best meet requirements. Two commercially available products, CAAPCO B-274 and Chemglaze M313, were subjected to further laboratory testing, airline service evaluations, and drag-measurement flight tests. It was found that these coatings were compatible with the severe operating environment of airlines and that coatings reduced airplane drag. An economic analysis indicated significant dollar benefits to airlines from application of the coatings.

  1. Coatings for Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Several approaches for applying high resistance coatings continuously to graphite yarn were investigated. Two of the most promising approaches involved (1) chemically vapor depositing (CVD) SiC coatings on the surface of the fiber followed by oxidation, and (2) drawing the graphite yarn through an organo-silicone solution followed by heat treatments. In both methods, coated fibers were obtained which exhibited increased electrical resistances over untreated fibers and which were not degraded. This work was conducted in a previous program. In this program, the continuous CVD SiC coating process used on HTS fiber was extended to the coating of HMS, Celion 6000, Celion 12000 and T-300 graphite fiber. Electrical resistances three order of magnitude greater than the uncoated fiber were measured with no significant degradation of the fiber strength. Graphite fibers coated with CVD Si3N4 and BN had resistances greater than 10(exp 6) ohm/cm. Lower pyrolysis temperatures were used in preparing the silica-like coatings also resulting in resistances as high as three orders of magnitude higher than the uncoated fiber. The epoxy matrix composites prepared using these coated fibers had low shear strengths indicating that the coatings were weak.

  2. Oxide coating development

    SciTech Connect

    Stinton, D.P.

    1995-06-01

    Monolithic SiC heat exchangers and fiber-reinforced SiC-matrix composite heat exchangers and filters are susceptible to corrosion by alkali metals at elevated temperatures. Protective coatings are currently being developed to isolate the SiC materials from the corrodants. Unfortunately, these coatings typically crack and spall when applied to SiC substrates. The purpose of this task is to determine the feasibility of using a compliant material between the protective coating and the substrate. The low-modulus compliant layer could absorb stresses and eliminate cracking and spalling of the protective coatings.

  3. Radical SAM, A Novel Protein Superfamily Linking Unresolved Steps in Familiar Biosynthetic Pathways with Radical Mechanisms: Functional Characterization Using New Analysis and Information Visualization Methods

    SciTech Connect

    Sofia, Heidi J.; Chen, Guang; Hetzler, Elizabeth G.; Reyes Spindola, Jorge F.; Miller, Nancy E.

    2001-03-01

    A large protein superfamily with over 500 members has been discovered and analyzed using powerful new bioinformatics and information visualization methods. Evidence exists that these proteins generate a 5?-deoxyadenosyl radical by reductive cleavage of S-adenosylmethionine (SAM) through an unusual Fe-S center. Radical SAM superfamily proteins function in DNA precursor, vitamin, cofactor, antibiotic, and herbicide biosynthesis in a collection of basic and familiar pathways. One of the members is interferon-inducible and is considered a candidate drug target for osteoporosis. The identification of this superfamily suggests that radical-based catalysis is important in a number of previously well-studied but unresolved biochemical pathways.

  4. Thermal Reactivity of Organic Molecules in the Presence of Chlorates and Perchlorates and the Quest for Organics on Mars with the SAM Experiment Onboard the Curiostiy Rover

    NASA Astrophysics Data System (ADS)

    Szopa, Cyril; Millan, Maeva; Buch, Arnaud; Belmahdi, Imene; Coll, Patrice; Glavin, Daniel P.; Freissinet, Caroline; Eigenbrode, Jennifer; archer, doug; sutter, brad; Summons, Roger; Navarro-Gonzalez, Rafael; Mahaffy, Paul; cabane, Michel

    2016-10-01

    One of the main objectives of the Sample Analysis at Mars (SAM) experiment is the in situ molecular analysis of gases evolving from solid samples collected by Curiosity when they are heated up to ~850°C. With this aim SAM uses a gas-chromatograph coupled to a mass spectrometer (GC-MS) able to detect and identify both inorganic and organic molecules released by the samples.During the pyrolysis, chemical reactions occur between oxychlorines, probably homogeneously distributed at Mars's surface, and organic compounds SAM seeks for. This was confirmed by the first chlorohydrocarbons (chloromethane and di- and trichloromethane) detected by SAM that were entirely attributed to reaction products occurring between these oxychlorines and organics from instrument background. But SAM also detected in the Sheepbed mudstone of Gale crater, chloroalkanes produced by reaction between oxychlorines and Mars indigenous organics, proving for the first time the presence of organics in the soil of Mars. However, the identification of the molecules at the origin of these chloroalkanes is much more difficult due to the complexity of the reactivity occurring during the sample pyrolysis. If a first study has already been done recently with this aim, it was relatively limited in terms of parameters investigated.This is the reason why, we performed a systematic study in the laboratory to help understanding the influence of oxychlorines on organic matter during pyrolysis. With this aim, different organic compounds from various chemical families (e.g. amino and carboxylic acids) mixed with different perchlorates and chlorates, in concentrations compatible with the Mars soil from estimations done with SAM measurements, were pyrolyzed under SAM like conditions. The products of reaction were analyzed and identified by GC-MS in order to show a possible correlation between them and the parent molecule. Different parameters were tested for the pyrolysis to evaluate their potential influence on the

  5. SAM Technical Review Committee Final Report: Summary and Key Recommendations from the Onsite TRC Meeting Held April 22-23, 2013

    SciTech Connect

    Blair, N.; Dobos, S.; Janzou, S.; Gilman, P.; Freeman, J.; Kaffine, L.

    2013-08-01

    The System Advisor Model (SAM) is a broad and robust set of models and frameworks for analyzing both system performance and system financing. It does this across a range of technologies dominated by solar technologies including photovoltaics (PV) and concentrated solar power (CSP). The U.S. Department of Energy (DOE) Solar Energy Technology Program requested the SAM development team to review the photovoltaic performance modeling with the development community and specifically, with the independent engineering community. The report summarizes the major effort for this technical review committee (TRC).

  6. In situ analysis of Mars soil sample with the sam gcms instrumentation onboard Curiosity : interpretation and comparison of measurements done at Rocknest and Yelloknife bay sites

    NASA Astrophysics Data System (ADS)

    Szopa, Cyril; Coll, Patrice; Cabane, Michel; Coscia, David; Buch, Arnaud; Francois, Pascaline; Millan, Maeva; Teinturier, Sammy; Navarro-Gonzales, Rafael; Glavin, Daniel; Freissinet, Caro; Steele, Andrew; Eigenbrode, Jen; Mahaffy, Paul

    2014-05-01

    The characterisation of the chemical and mineralogical composition of regolith samples collected with the Curiosity rover is a primary objective of the SAM experiment. These data should provide essential clues on the past habitability of Gale crater. Amongst the SAM suite of instruments [1], SAM-GC (Gas Chromatograph) is devoted to identify and quantify volatiles evolved from the thermal (heating up to about 900°C)/chemical (derivatization procedure) treatment of any soil sample collected by the Curiosity rover. With the aim to search for potential organic molecules outgassed from the samples, a SAM-GC analytical channel composed of thermal-desorption injector and a MXT-CLP chromatographic column was chosen to achieve all the measurements done up today, as it was designed for the separation of a wide range of volatile organic molecules. Three solid samples have been analyzed with GCMS, one sand sample collected at the Rocknest site, and two rock samples (John Klein and Cumberland respectively) collected at the Yellowknife Bay site using the Curiosity driller. All the measurements were successful and they produced complex chromatograms with both detectors used for SAM GC, i.e. a thermal conductivity detector and the SAM quandrupole mass spectrometer. Their interpretation already revealed the presence of an oxychlorine phase present in the sample which is at the origin of chlorohydrocarbons clearly identified [2] but this represents only a fraction of the GCMS signal recorded [3,4]. This work presents a systematic comparison of the GCMS measurements done for the different samples collected, supported by reference data obtained in laboratory with different spare models of the gas chromatograph, with the aim to bring new elements of interpretation of the SAM measurements. References: [1] Mahaffy, P. et al. (2012) Space Sci Rev, 170, 401-478. [2] Glavin, D. et al. (2013), JGR. [3] Leshin L. et al. (2013), Science, [4] Ming D. et al. (2013), Science, 32, 64

  7. SAM-like Evolved Gas Analysis of Mars Analog Samples from the Arctic Mars Analog Svalbard Expedition: Implications for Analyses by the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    McAdam, A.; Stern, J. C.; Mahaffy, P. R.; Blake, D. F.; Morris, R. V.; Ming, D. W.; Bristow, T.; Steele, A.; Amundsen, H.

    2012-12-01

    The Arctic Mars Analog Svalbard Expeditions (AMASE) have investigated a range of geologic settings on Svalbard, using methodologies and techniques being developed for Mars missions, such as the Mars Science Laboratory (MSL). The Sample Analysis at Mars (SAM) instrument suite on MSL consists of a quadrupole mass spectrometer (QMS), a gas chromatograph (GC), and a tunable laser spectrometer (TLS), which analyze gases created by pyrolysis of samples. During AMASE, a Hiden Evolved Gas Analysis-Mass Spectrometer (EGA-QMS) system represented the EGA-QMS capability of SAM. Another MSL instrument, CheMin, will use x-ray diffraction (XRD) and x-ray fluorescence (XRF) to perform quantitative mineralogical characterization of samples. Field-portable versions of CheMin were used during AMASE. Here we discuss the SAM-like EGA-QMS analyses of a selected subset of samples acquired during several field seasons, together with AMASE CheMin team results. The results enable insight into organic content, organic-mineral associations, and mineralogy. Organic materials evolved from all samples over a range of temperatures. In general, this can indicate that the organics have a range of thermal maturity and/or are bound in different ways to their matrix. Most often, organics that were outside of mineral grains were the dominant pool of organic material inferable from the EGA-QMS, but organics encapsulated within mineral grains, including possibly methane, were also inferred. Organic-mineral associations can influence organic preservation potential and detection. Constraints on these associations, and overall sample organic chemistry, enabled by our SAM-like EGA-QMS analog analyses demonstrate the potential to understand the organic chemical characteristics in materials sampled by MSL, even when utilizing EGA-QMS, the simplest type of solid sample experiment SAM will perform. Any organic chemical information inferred from EGA-QMS analysis could then also be followed by detailed SAM EGA

  8. Beam Damage of HS (CH2)15 COOH Terminated Self Assembled Monolayer (SAM) as Observed by X-Ray Photoelectron Spectroscopy

    SciTech Connect

    Engelhard, Mark H.; Tarasevich, Barbara J.; Baer, Donald R.

    2011-10-25

    XPS spectra of HS(CH{sub 2}){sub 15} COOH terminated a self assembled monolayer (SAM)sample was collected over a period of 242 minutes to determine specimen damage during long exposures to monochromatic Al Ka x-rays. For this COOH terminated SAM we measured the loss of oxygen as a function of time by rastering a focused 100 W, 100 um diameter x-ray beam over a 1.4 mm x 0.2 mm area of the sample.

  9. Satellite and correlative measurements of the stratospheric aerosol. III - Comparison of measurements by SAM II, SAGE, dustsondes, filters, impactors and lidar

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Mccormick, M. P.; Mcmaster, L. R.; Swissler, T. J.; Rosen, J. M.; Hofmann, D. J.

    1984-01-01

    The SAM II and SAGE satellite sensors, dustsondes, impactors, a filter collector and an airborne lidar were used in a large satellite validation experiment on July 16-19, 1979, at Poker Flat, Alaska. Independent measurements of extinction profiles by SAM II and SAGE are noted to agree with each other and with those derived from the other instruments (within combined uncertainties). The wire impactor-derived results, while also consistent with the others, are coarse due to the relatively large uncertainties in impactor-derived mass, extinction, and number of particles/unit volume whose radius is greater than x microns.

  10. Combustion chemical vapor deposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-12-31

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings. In this report, the evaluation of alumina and ceria coatings on a nickel-chromium alloy is described.

  11. Detecting Organic Compounds Released from Iron Oxidizing Bacteria using Sample Analysis at Mars (SAM) Like Instrument Protocols

    NASA Technical Reports Server (NTRS)

    Glavin, D. P.; Popa, R.; Martin, M. G.; Freissinet, C.; Fisk, M. R.; Dworkin, J. P.; Mahaffy, P. R.

    2012-01-01

    Mars is a planet of great interest for Astrobiology since its past environmental conditions are thought to have been favourable for the emergence life. At present, the Red Planet is extremely cold and dry and the surface is exposed to intense UV and ionizing radiation, conditions generally considered to be incompatible with life as we know it on Earth. It was proposed that the shallow subsurface of Mars, where temperatures can be above freezing and liquid water can exist on rock surfaces, could harbor chemolithoautotrophic bacteria such as the iron oxidizing microorganism Pseudomonas sp. HerB. The Mars Science Laboratory (MSL) mission will provide the next opportunity to carry out in situ measurements for organic compounds of possible biological origin on Mars. One instrument onboard MSL, called the Sample Analysis at Mars (SAM) instrument suite, will carry out a broad and sensitive search for organic compounds in surface samples using either high temperature pyrolysis or chemical extraction followed by gas chromatography mass spectrometry. We present gas chromatograph mass spectrometer (GC/MS) data on crushed olivine rock powders that have been inoculated with Pseudomonas sp. HerB at different concentrations ranging from approx 10(exp 2) to 10(exp 7) cells per gram. The inoculated olivine samples were heated under helium carrier gas flow at 500 C and the pyrolysis products concentrated using a SAM-like hydrocarbon trap set at -20 C followed by trap heating and analysis by GC/Ms. In addition, the samples were also extracted using a low temperature "one-pot" chemical extraction technique using N-methyl, N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) as the silylating agent prior to GC/MS analysis. We identified several aldehydes, thiols, and alkene nitriles after pyrolysis GC/MS analysis of the bacteria that were not found in the olivine control samples that had not been inoculated with bacteria. The distribution of pyrolysis products extracted from the

  12. Duplex aluminized coatings

    NASA Technical Reports Server (NTRS)

    Gedwill, M. A.; Grisaffe, S. J. (Inventor)

    1975-01-01

    The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.

  13. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-04-07

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  14. Thermal barrier coating

    DOEpatents

    Bowker, Jeffrey Charles; Sabol, Stephen M.; Goedjen, John G.

    2001-01-01

    A thermal barrier coating for hot gas path components of a combustion turbine based on a zirconia-scandia system. A layer of zirconium scandate having the hexagonal Zr.sub.3 Sc.sub.4 O.sub.12 structure is formed directly on a superalloy substrate or on a bond coat formed on the substrate.

  15. Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  16. Coated electroactive materials

    DOEpatents

    Amine, Khalil; Abouimrane, Ali

    2016-08-30

    A process includes suspending an electroactive material in a solvent, suspending or dissolving a carbon precursor in the solvent; and depositing the carbon precursor on the electroactive material to form a carbon-coated electroactive material. Compositions include a graphene-coated electroactive material prepared from a solution phase mixture or suspension of an electroactive material and graphene, graphene oxide, or a mixture thereof.

  17. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1985-01-01

    An oxide thermal barrier coating comprises ZrO3-Yb2O3 that is plasma sprayed onto a previously applied bond coating. The zirconia is partially stabilized with about 124 w/o ytterbia to insure cubic, monoclinic, and terragonal phases.

  18. Anti-Corrosion Coating

    NASA Technical Reports Server (NTRS)

    1977-01-01

    NASA-Goddard developed a zinc-rich coating with a special binder that exhibits longer life and booths with the air purifiers. superior adhesion characteristics-so that only a single coat is required. Unlike conventional coatings, . the NASA compound is easy to mix and it requires no straining before application; its materials also cost less. Thus the new coating offers cost advantages in materials, labor hours per application, and fewer applications over a given time span. The NASA coating is now undergoing test on a number of coastal area structures. In a cooperative effort with the Philadelphia Mayor's Science and Technology Council, the coating has been applied to sample sections of the Frankford Elevated System's steel support structure. On the West Coast, it is being tested on facilities of the Pillar Point Satellite Tracking Station, Pillar Point, Cat. and on segments of the Golden Gate Bridge. It is also undergoing evaluation as an undercoating to protect road equipment against de-icing salts; the coating was applied to the underside of a truck and its performance is being recorded periodically by the Vermont Department of Highways. NASA has issued patent licenses to two paint companies and the coating is expected to be commercially available this year.

  19. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-01-01

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  20. Development of nanostructured coatings for protecting the surface of aluminum alloys against corrosion and ice accretion

    NASA Astrophysics Data System (ADS)

    Farhadi, Shahram

    Ice and wet snow accretion on outdoor structures is a severe challenge for cold climate countries. A variety of de-icing and anti-icing techniques have been developed so far to counter this problem. Passive approaches such as anti-icing or icephobic coatings that inhibit or retard ice accumulation on the surfaces are gaining in popularity. Metal corrosion should also be taken into account as metallic substrates are subject to corrosion problems when placed in humid or aggressive environments. Development of any ice-releasing coatings on aluminum structures, as they must be durable enough, is therefore closely related to anti-corrosive protection of that metal. Accordingly, series of experiments have been carried out to combine reduced ice adhesion and improved corrosion resistance on flat AA2024 substrates via thin films of single and double layer alkyl-terminated SAMs coatings. More precisely, alkyl-terminated aluminum substrates were prepared by depositing layer(s) of 18C-SAMs on BTSE-grafted AA2024 or mirror-polished AA2024 surfaces. This alloy is among the most widely used aluminum alloys in transportation systems (including aircraft), the military, etc. The stability of the coatings in an aggressive environment, their overall ice-repellent performance as well as their corrosion resistance was systematically studied. The stability of one-layer and two-layer coatings in different media was tested by means of CA measurements, demonstrating gradual loss of the hydrophobic property after ~1100-h-long immersion in water, associated by decrease in water CA. Surface corrosion was observed in all cases, except that the double-layer coating system provided improved anti-corrosive protection. All single layer coatings showed initial shear stress of ice detachment values of ~1.68 to 2 times lower than as-received aluminum surfaces and about ~1.22 to 1.5 times lower than those observed on mirror-polished surfaces. These values gradually increased after as many as 5 to 9

  1. SAP Minutes No.2015-03 for FIFRA meeting held 9/15-17/2015. A set of scientific issues being considered by the Environmental Protection Agency regarding development of a spatial aquatic model(SAM)for pesticide risk assessment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On September 15-17th, 2014, the US Environmental Protection Agency convened a public meeting of the FIFRA Scientific Advisory Panel (SAP) to address scientific issues associated with the agency’s “Development of a Spatial Aquatic Model (SAM) for Pesticide Risk Assessment”. The goal of SAM is to impr...

  2. Thermal barrier coatings

    SciTech Connect

    Alvin, Mary Anne

    2010-06-22

    This disclosure addresses the issue of providing a metallic-ceramic overlay coating that potentially serves as an interface or bond coat layer to provide enhanced oxidation resistance to the underlying superalloy substrate via the formation of a diffusion barrier regime within the supporting base material. Furthermore, the metallic-ceramic coating is expected to limit the growth of a continuous thermally grown oxide (TGO) layer that has been primarily considered to be the principal cause for failure of existing TBC systems. Compositional compatibility of the metallic-ceramic with traditional yttria-stabilized zirconia (YSZ) top coats is provided to further limit debond or spallation of the coating during operational use. A metallic-ceramic architecture is disclosed wherein enhanced oxidation resistance is imparted to the surface of nickel-based superalloy or single crystal metal substrate, with simultaneous integration of the yttria stabilized zirconia (YSZ) within the metallic-ceramic overlayer.

  3. LEVELING METAL COATINGS

    DOEpatents

    Gage, H.A.

    1959-02-10

    A method is described for applying metallic coatings to a cylinder of uranium. An aluminum-silicon coat is applied by a process consisting of first cleaning the article by immersion for 5 minutes in 50% nitric acid at 65 C. The article then is dipped through a flux, prepared by adding 10% sodium fluoride to 90% of a flux comprising 53% potassium chloride, 42% lithium chloride, and 5% sodium chloride at 560 for 2 minutes and then directly into a molten metal bath comprising 99% aluminun and 12% silicon at 620 C for 3 minutes. While the coating is yet molten the article is transferred to a pair of steel rollers and rolled until the coating solidifies. By varying the composition of the flux other metals such as zinc, lead or the like may be coated on uranium in a similar manner.

  4. Catalytic thermal barrier coatings

    DOEpatents

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  5. Detecting Organic Compounds Released from Iron Oxidizing Bacteria using Sample Analysis at Mars (SAM)-like Instrument Protocols

    NASA Astrophysics Data System (ADS)

    Glavin, D. P.; Popa, R.; Martin, M. G.; Freissinet, C.; Fisk, M. R.; Dworkin, J. P.; Mahaffy, P. R.

    2012-12-01

    Mars is a planet of great interest for Astrobiology since its past environmental conditions are thought to have been favourable for the emergence life. At present, the Red Planet is extremely cold and dry and the surface is exposed to intense UV and ionizing radiation, conditions generally considered to be incompatible with life as we know it on Earth. It was proposed that the shallow subsurface of Mars, where temperatures can be above freezing and liquid water can exist on rock surfaces, could harbor chemolithoautotrophic bacteria such as the iron oxidizing microorganism Pseudomonas sp. HerB [Popa et al. 2012]. The Mars Science Laboratory (MSL) mission will provide the next opportunity to carry out in situ measurements for organic compounds of possible biological origin on Mars. One instrument onboard MSL, called the Sample Analysis at Mars (SAM) instrument suite, will carry out a broad and sensitive search for organic compounds in surface samples using either high temperature pyrolysis or chemical extraction followed by gas chromatography mass spectrometry [Mahaffy et al. 2012]. We present gas chromatograph mass spectrometer (GC/MS) data on crushed olivine rock powders that have been inoculated with Pseudomonas sp. HerB at different concentrations ranging from ~102 to 107 cells per gram. The inoculated olivine samples were heated under helium carrier gas flow at 500°C and the pyrolysis products concentrated using a SAM-like hydrocarbon trap set at -20°C followed by trap heating and analysis by GC/MS. In addition, the samples were also extracted using a low temperature "one-pot" chemical extraction technique using N-methyl, N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) as the silylating agent prior to GC/MS analysis [Stalport et al. 2012]. We identified several aldehydes, thiols, and alkene nitriles after pyrolysis GC/MS analysis of the bacteria that were not found in the olivine control samples that had not been inoculated with bacteria. The

  6. Colloidal silicon quantum dots: from preparation to the modification of self-assembled monolayers (SAMs) for bio-applications.

    PubMed

    Cheng, Xiaoyu; Lowe, Stuart B; Reece, Peter J; Gooding, J Justin

    2014-04-21

    Concerns over possible toxicities of conventional metal-containing quantum dots have inspired growing research interests in colloidal silicon nanocrystals (SiNCs), or silicon quantum dots (SiQDs). This is related to their potential applications in a number of fields such as solar cells, optoelectronic devices and fluorescent bio-labelling agents. The past decade has seen significant progress in the understanding of fundamental physics and surface properties of silicon nanocrystals. Such understanding is based on the advances in the preparation and characterization of surface passivated colloidal silicon nanocrystals. In this critical review, we summarize recent advances in the methods of preparing high quality silicon nanocrystals and strategies for forming self-assembled monolayers (SAMs), with a focus on their bio-applications. We highlight some of the major challenges that remain, as well as lessons learnt when working with silicon nanocrystals (239 references).

  7. Mesospheric effects of solar ultraviolet variations - Further analysis of SME IR ozone and Nimbus 7 SAMS temperature data

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Huang, Z.; Bougher, S. W.

    1991-01-01

    In order to improve the constraints on models of the mesospheric response to solar UV variations, an analysis is conducted of the Solar Mesosphere Explorer (SME) IR ozone data and Nimbus 7 stratosphere and mesosphere sounder (SAMS) temperature data. Maximum low-altitude ozone and temperature-response amplitudes occur at about the same altitude, where a strong coupling between photochemical and thermal components of the mesospheric response is suggested by the simultaneous positive temperature and negative ozone response maxima. Increased Lyman-alpha dissociation of water vapor and temperature feedback are theorized to account for the negative ozone response. HO(x) chemical heating can increase as ozone destruction increases, and can therefore account for the positive temperature response.

  8. Utilization of LANDSAT multispectral data in geobotanical investigations: The location of ironstone gravel in the Sam Houston National Forest

    NASA Technical Reports Server (NTRS)

    Cibula, W. G.

    1982-01-01

    Practical techniques were developed and evaluated for deriving geobotanical information from LANDSAT MSS data acquired for a test site in the Sam Houston National Forest near Cleveland, Texas where gravel deposits exist in sufficient quantity that economical extraction would be feasible. A correlation was shown between a single spectral class and the presence of ironstone gravel. Field data indicates that this class relates to upland pine which was probably under stress as the result of a prolonged drought which was in progress at the time of data acquisition. It is suggested that the subsurface gravel produces a soil which has less field capacity for water retention, causing early appearance of water stress in the surface vegetation over these soils. In all areas within the QMC formation where this class occurred, gravel was located when borings were made.

  9. Coating Reduces Ice Adhesion

    NASA Technical Reports Server (NTRS)

    Smith, Trent; Prince, Michael; DwWeese, Charles; Curtis, Leslie

    2008-01-01

    The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties. SILC is made of a binder composed of varying weight percents of siloxane(s), ethyl alcohol, ethyl sulfate, isopropyl alcohol, and of fine-particle polytetrafluoroethylene (PTFE). The combination of these components produces a coating with significantly improved weathering characteristics over the siloxane system alone. In some cases, the coating will delay ice formation and can reduce the amount of ice formed. SILC is not an ice prevention coating, but the very high water contact angle (greater than 140 ) causes water to readily run off the surface. This coating was designed for use at temperatures near -170 F (-112 C). Ice adhesion tests performed at temperatures from -170 to 20 F (-112 to -7 C) show that SILC is a very effective ice release coating. SILC can be left as applied (opaque) or buffed off until the surface appears clear. Energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) data show that the coating is still present after buffing to transparency. This means SILC can be used to prevent ice adhesion even when coating windows or other objects, or items that require transmission of optical light. Car windshields are kept cleaner and SILC effectively mitigates rain and snow under driving conditions.

  10. Microbial Habitability in Gale Crater: Sample Analysis at Mars (SAM) Instrument Detection of Microbial Essential Carbon and Nitrogen

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Ming, D. W.; Eigenbrode, J. E.; Steele, A.; Stern, J. C.; Gonzalez, R. N.; McAdam, A. C.; Mahaffy, P. R.

    2016-01-01

    Chemical analyses of Mars soils and sediments from previous landed missions have demonstrated that Mars surface materials possessed major (e.g., P, K, Ca, Mg, S) and minor (e.g., Fe, Mn, Zn, Ni, Cl) elements essential to support microbial life. However, the detection of microbial essential organic-carbon (C) and nitrate have been more elusive until the Mars Science Laboratory (MSL) rover mission. Nitrate and organic-C in Gale Crater, Mars have been detected by the Sample Analysis at Mars (SAM) instrument onboard the MSL Curiosity rover. Eolian fines and drilled sedimentary rock samples were heated in the SAM oven from approximately 30 to 860 degrees Centigrade where evolved gases (e.g., nitrous oxide (NO) and CO2) were released and analyzed by SAM’s quadrupole mass spectrometer (MS). The temperatures of evolved NO was assigned to nitrate while evolved CO2 was assigned to organic-C and carbonate. The CO2 releases in several samples occurred below 450 degrees Centigrade suggesting organic-C dominated in those samples. As much as 7 micromoles NO3-N per gram and 200 micromoles CO2-C per gram have been detected in the Gale Crater materials. These N and C levels coupled with assumed microbial biomass (9 x 10 (sup -7) micrograms per cell) C (0.5 micrograms C per micrograms cell) and N (0.14 micrograms N per micrograms cell) requirements, suggests that less than 1 percent and less than 10 percent of Gale Crater C and N, respectively, would be required if available, to accommodate biomass requirements of 1 by 10 (sup 5) cells per gram sediment. While nitrogen is the limiting nutrient, the potential exists that sufficient N and organic-C were present to support limited heterotrophic microbial populations that may have existed on ancient Mars.

  11. Mars Atmospheric Composition, Isotope Ratios and Seasonal Variations: Overview and Updates of the SAM Measurements at Gale Crater

    NASA Astrophysics Data System (ADS)

    Webster, C. R.; Mahaffy, P. R.; Atreya, S. K.; Conrad, P. G.; Franz, H.; Trainer, M. G.; Wong, M. H.; Mischna, M. A.; Flesch, G.; Farley, K. A.; Owen, T. C.; Niles, P. B.; Jones, J. H.; Christensen, L. E.; Martín-Torres, J.; Zorzano, M. P.

    2014-12-01

    We will summarize the in situ measurements of atmospheric composition and the isotopic ratios of D/H in water, 13C/12C, 18O/16O, 17O/16O, and 13C18O/12C16O in carbon dioxide, 38Ar/36Ar, xKr/84Kr, and 15N/14N made in the martian atmosphere at Gale Crater from the Curiosity Rover using the Sample Analysis at Mars (SAM)'s Quadrupole Mass Spectrometer (QMS) and Tunable Laser Spectrometer (TLS). With data over 700 sols since the Curiosity landing, we will discuss evidence and implications for changes on seasonal and other timescales. We will also present results for continued methane and methane enrichment experiments over this time period. Comparison between our measurements in the modern atmosphere and those of martian meteorites like ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established ~4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing. References:[1] Mahaffy P. R. et al., Science, 341, 263-266, 2013, doi:10.1126/science.1237966. [2] Webster C. R. et al. (2013), Science, 341, 260-263, doi:10.1126/science.1237961. [3] Wong, M. H. et al. (2013), Geophys. Res. Lett., doi:10.1002/2013GL057840. [4] Atreya S. K. et al (2013), Geophys. Res. Lett., 40, 1-5, doi:10.1002/2013GL057763. The research described here was supported by the National Aeronautics and Space Administration (NASA).

  12. A spatial analysis method (SAM) to detect candidate loci for selection: towards a landscape genomics approach to adaptation.

    PubMed

    Joost, S; Bonin, A; Bruford, M W; Després, L; Conord, C; Erhardt, G; Taberlet, P

    2007-09-01

    The detection of adaptive loci in the genome is essential as it gives the possibility of understanding what proportion of a genome or which genes are being shaped by natural selection. Several statistical methods have been developed which make use of molecular data to reveal genomic regions under selection. In this paper, we propose an approach to address this issue from the environmental angle, in order to complement results obtained by population genetics. We introduce a new method to detect signatures of natural selection based on the application of spatial analysis, with the contribution of geographical information systems (GIS), environmental variables and molecular data. Multiple univariate logistic regressions were carried out to test for association between allelic frequencies at marker loci and environmental variables. This spatial analysis method (SAM) is similar to current population genomics approaches since it is designed to scan hundreds of markers to assess a putative association with hundreds of environmental variables. Here, by application to studies of pine weevils and breeds of sheep we demonstrate a strong correspondence between SAM results and those obtained using population genetics approaches. Statistical signals were found that associate loci with environmental parameters, and these loci behave atypically in comparison with the theoretical distribution for neutral loci. The contribution of this new tool is not only to permit the identification of loci under selection but also to establish hypotheses about ecological factors that could exert the selection pressure responsible. In the future, such an approach may accelerate the process of hunting for functional genes at the population level.

  13. Predictions of psychophysical measurements for sinusoidal amplitude modulated (SAM) pulse-train stimuli from a stochastic model.

    PubMed

    Xu, Yifang; Collins, Leslie M

    2007-08-01

    Two approaches have been proposed to reduce the synchrony of the neural response to electrical stimuli in cochlear implants. One approach involves adding noise to the pulse-train stimulus, and the other is based on using a high-rate pulse-train carrier. Hypotheses regarding the efficacy of the two approaches can be tested using computational models of neural responsiveness prior to time-intensive psychophysical studies. In our previous work, we have used such models to examine the effects of noise on several psychophysical measures important to speech recognition. However, to date there has been no parallel analytic solution investigating the neural response to the high-rate pulse-train stimuli and their effect on psychophysical measures. This work investigates the properties of the neural response to high-rate pulse-train stimuli with amplitude modulated envelopes using a stochastic auditory nerve model. The statistics governing the neural response to each pulse are derived using a recursive method. The agreement between the theoretical predictions and model simulations is demonstrated for sinusoidal amplitude modulated (SAM) high rate pulse-train stimuli. With our approach, predicting the neural response in modern implant devices becomes tractable. Psychophysical measurements are also predicted using the stochastic auditory nerve model for SAM high-rate pulse-train stimuli. Changes in dynamic range (DR) and intensity discrimination are compared with that observed for noise-modulated pulse-train stimuli. Modulation frequency discrimination is also studied as a function of stimulus level and pulse rate. Results suggest that high rate carriers may positively impact such psychophysical measures.

  14. The Investigation of Chlorates as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Archer, D. P.; Ming, D. W.; Niles, P. B.; Eigenbrode, J. L.; Franz, H.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P; Stern, J. C.; Navarro-Gonzalez, R.; McKay, C. .P.

    2014-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detect-ed O2 and HCl gas releases from the Rocknest (RN) eolian bedform and the John Klein (JK) and Cumberland (CB) drill hole materials in Gale Crater. Chlorinated hydrocarbons have also been detected by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS). These detections along with the detection of perchlorate (ClO4-) by the Mars Phoenix Lander’s Wet Chemistry Laboratory (WCL) suggesting perchlorate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of perchlorates has yet to provide an unequivocal temperature match to the SAM O2 and HCl release data. Iron mineralogy found in the Rocknest materials when mixed with Ca-perchlorate does cause O2 release temperatures to be closer match to the SAM O2 release data but more work is required in evaluating the catalytic effects of Fe mineralogy on perchlorate decomposition. Chlorates (ClO3-) are relevant Mars materials and potential O2 and Cl sources. The objective of this work is to evaluate the thermal decomposition of select chlorate (ClO3-) salts as possible sources of the O2 and HCl releases in the Gale Crater materials.

  15. In situ analysis of Mars soil and rocks samples with the SAM experiment: laboratory measurements supporting treatment and interpretation of the detection of organics

    NASA Astrophysics Data System (ADS)

    Millan, M.; Szopa, C.; Buch, A.; Glavin, D.; Freissinet, C.; Coll, P.; Cabane, M.; Mahaffy, P.

    2015-10-01

    The Sample Analysis at Mars (SAM) experiment onboard the Curiosity rover detected numerous organic compounds when analyzing the solid samples collected on the way to Mount Sharp. But MTBSTFA, the chemical reactant for the chemical treatment of the refractory molecules present in the solid samples and present in cups of SAM,was shown to be unfortunately present in the Sample Manipulation System(SMS). During the sample analysis, this chemical species reacts with the organic and inorganic molecules present in the samples. This reaction leads to the production and subsequent detection of numerous MTBSTFA derivatives which makes the treatment and the interpretation of the SAM data complex. Moreover, for the first time on Mars, the wet chemistry method was used on a Cumberland sample to help the GC separation and the MS identification of non volatile compounds. To ensure the identification of the organic molecules and try to discriminate organics generated internally to SAM from those present in the samples analyzed, it is mandatory to perform laboratory experimental calibrations under martian operating conditions.

  16. SAM-Net (SCIENCE and MATH on the Net): Connecting Students and Teachers To Scientific Research through Scientific Communication and Electronic Networking.

    ERIC Educational Resources Information Center

    Bartolo, Laura M.; Palffy-Muhoray, Peter

    1998-01-01

    Introducing students and teachers to the social structure of scientific communication as part of a hands-on, minds-on approach can increase students' knowledge and interest in the sciences. Describes SAM-Net which incorporates scientific communication, electronic networking, and scientific research as practiced by scientists into a K-12 science…

  17. SAMS, a syndrome of short stature, auditory-canal atresia, mandibular hypoplasia, and skeletal abnormalities is a unique neurocristopathy caused by mutations in Goosecoid.

    PubMed

    Parry, David A; Logan, Clare V; Stegmann, Alexander P A; Abdelhamed, Zakia A; Calder, Alistair; Khan, Shabana; Bonthron, David T; Clowes, Virginia; Sheridan, Eamonn; Ghali, Neeti; Chudley, Albert E; Dobbie, Angus; Stumpel, Constance T R M; Johnson, Colin A

    2013-12-05

    Short stature, auditory canal atresia, mandibular hypoplasia, and skeletal abnormalities (SAMS) has been reported previously to be a rare, autosomal-recessive developmental disorder with other, unique rhizomelic skeletal anomalies. These include bilateral humeral hypoplasia, humeroscapular synostosis, pelvic abnormalities, and proximal defects of the femora. To identify the genetic basis of SAMS, we used molecular karyotyping and whole-exome sequencing (WES) to study small, unrelated families. Filtering of variants from the WES data included segregation analysis followed by comparison of in-house exomes. We identified a homozygous 306 kb microdeletion and homozygous predicted null mutations of GSC, encoding Goosecoid homeobox protein, a paired-like homeodomain transcription factor. This confirms that SAMS is a human malformation syndrome resulting from GSC mutations. Previously, Goosecoid has been shown to be a determinant at the Xenopus gastrula organizer region and a segment-polarity determinant in Drosophila. In the present report, we present data on Goosecoid protein localization in staged mouse embryos. These data and the SAMS clinical phenotype both suggest that Goosecoid is a downstream effector of the regulatory networks that define neural-crest cell-fate specification and subsequent mesoderm cell lineages in mammals, particularly during shoulder and hip formation. Our findings confirm that Goosecoid has an essential role in human craniofacial and joint development and suggest that Goosecoid is an essential regulator of mesodermal patterning in mammals and that it has specific functions in neural crest cell derivatives.

  18. Sam68 promotes self-renewal and glycolytic metabolism in mouse neural progenitor cells by modulating Aldh1a3 pre-mRNA 3'-end processing

    PubMed Central

    La Rosa, Piergiorgio; Bielli, Pamela; Compagnucci, Claudia; Cesari, Eleonora; Volpe, Elisabetta; Farioli Vecchioli, Stefano; Sette, Claudio

    2016-01-01

    The balance between self-renewal and differentiation of neural progenitor cells (NPCs) dictates neurogenesis and proper brain development. We found that the RNA- binding protein Sam68 (Khdrbs1) is strongly expressed in neurogenic areas of the neocortex and supports the self-renewing potential of mouse NPCs. Knockout of Khdrbs1 constricted the pool of proliferating NPCs by accelerating their cell cycle exit and differentiation into post-mitotic neurons. Sam68 function was linked to regulation of Aldh1a3 pre-mRNA 3'-end processing. Binding of Sam68 to an intronic polyadenylation site prevents its recognition and premature transcript termination, favoring expression of a functional enzyme. The lower ALDH1A3 expression and activity in Khdrbs1-/- NPCs results in reduced glycolysis and clonogenicity, thus depleting the embryonic NPC pool and limiting cortical expansion. Our study identifies Sam68 as a key regulator of NPC self-renewal and establishes a novel link between modulation of ALDH1A3 expression and maintenance of high glycolytic metabolism in the developing cortex. DOI: http://dx.doi.org/10.7554/eLife.20750.001 PMID:27845622

  19. Study of Fused Thiophene Based Organic Semiconductors and Interfacial Self-Assembled Monolayer (SAM) for Thin-Film Transistor (TFT) Application

    NASA Astrophysics Data System (ADS)

    Youn, Jangdae

    In this thesis, the molecular packing motifs of our newly designed fused thiophenes, benzo[d,d]thieno[3,2-b;4,5-b]dithiophene (BTDT) derivatives, were studied by utilizing grazing incidence wide angle X-ray scattering (GIWAXS). Considering the potential of fused thiophene molecules as an environmentally stable, high performance semiconductor building block, it must be an important groundwork to investigate their thin film structures in relation to molecular structures, single crystal structures, and organic thin-film transistors (OTFT) performances. OTFT device performance is not only determined by semiconductor materials, but also influenced by the interfacial properties. Since there are three major components in TFT structures---electrodes, semiconductors, and dielectrics, two types of major interfaces exist. One is the semiconductor-electrode interface, and the other is the semiconductor-dielectric interface. Both of these interfaces have critical roles for TFT operation. For example, the semiconductor-electrode interface determines the charge injection barrier. Before charge carriers go through the electrode (source)-semiconductor-electrode (drain) pathways, the energy gaps between the work function of the electrodes and the HOMO energy of the semiconductor materials must be overcome for hole injection, or the energy gap between the metal work function of the electrodes and the LUMO energy of the semiconductor materials must be overcome for electron injection. These charge injection barriers are largely determined by the energetic structure of the semiconductor material and work function of the electrode. However, the size of energy gap can be modified by introducing an organic self-assembled monolayer (SAM) on the surface of metal electrode. In addition, the structure of semiconductor films, especially within several monolayers right above the electrode, is greatly influenced by the SAM, and it changes charge injection property of OTFT devices. In this thesis

  20. Effect of the Presence of Chlorates and Perchlorates on the Pyrolysis of Organic Compounds: Implications for Measurements Done with the SAM Experiment Onboard the Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Millan, M.; Szopa, C.; Buch, A.; Belmahdi, I.; Coll, P.; Glavin, D. P.; Freissinet, C.; Archer, P. D., Jr.; Sutter, B.; Summons, R. E.; Mahaffy, P.

    2016-01-01

    The Mars Science Laboratory (MSL) Curiosity Rover carries a suite of instruments, one of which is the Sample Analysis at Mars (SAM) experiment. SAM is devoted to the in situ molecular analysis of gases evolving from solid samples collected by Curiosity on Mars surface/sub-surface. Among its three analytical devices, SAM has a gaschromatograph coupled to a quadrupole mass spectrometer (GC-QMS). The GC-QMS is devoted to the separation and identification of organic and inorganic material. Before proceeding to the GC-QMS analysis, the solid sample collected by Curiosity is subjected to a thermal treatment thanks to the pyrolysis oven to release the volatiles into the gas processing system. Depending on the sample, a derivatization method by wet chemistry: MTBSTFA of TMAH can also be applied to analyze the most refractory compounds. The GC is able to separate the organic molecules which are then detected and identified by the QMS (Figure 1). For the second time after the Viking landers in 1976, SAM detected chlorinated organic compounds with the pyrolysis GC-QMS experiment. The detection of perchlorates salts (ClO4-) in soil at the Phoenix Landing site suggests that the chlorohydrocarbons detected could come from the reaction of organics with oxychlorines. Indeed, laboratory pyrolysis experiments have demonstrated that oxychlorines decomposed into molecular oxygen and volatile chlorine (HCl and/or Cl2) when heated which then react with the organic matter in the solid samples by oxidation and/or chlorination processes.

  1. Active Region Soft X-Ray Spectra as Observed Using Sounding Rocket Measurements from the Solar Aspect Monitor (SAM), - a Modified SDO/EVE Instrument

    NASA Astrophysics Data System (ADS)

    Wieman, S. R.; Didkovsky, L. V.; Woods, T. N.; Jones, A. R.; Caspi, A.; Warren, H. P.

    2015-12-01

    Observations of solar active regions (ARs) in the soft x-ray spectral range (0.5 to 3.0 nm) were made on sounding rocket flight NASA 36.290 using a modified Solar Aspect Monitor (SAM), a pinhole camera on the EUV Variability Experiment (EVE) sounding rocket instrument. The suite of EVE rocket instruments is designed for under-flight calibrations of the orbital EVE on SDO. While the sounding rocket EVE instrument is for the most part a duplicate of the EVE on SDO, the SAM channel on the rocket version was modified in 2012 to include a free-standing transmission grating so that it could provide spectrally resolved images of the solar disk with the best signal to noise ratio for the brightest features on it, such as ARs. Calibrations of the EVE sounding rocket instrument at the National Institute of Standards and Technology Synchrotron Ultraviolet Radiation Facility (NIST SURF) have provided a measurement of the SAM absolute spectral response function and a mapping of wavelength separation in the grating diffraction pattern. For solar observations, this spectral separation is on a similar scale to the spatial size of the AR on the CCD, so dispersed AR images associated with emission lines of similar wavelength tend to overlap. Furthermore, SAM shares a CCD detector with MEGS-A, a separate EVE spectrometer channel, and artifacts of the MEGS-A signal (a set of bright spectral lines) appear in the SAM images. For these reasons some processing and analysis of the solar images obtained by SAM must be performed in order to determine spectra of the observed ARs. We present a method for determining AR spectra from the SAM rocket images and report initial soft X-ray spectra for two of the major active regions (AR11877 and AR11875) observed on flight 36.290 on 21 October 2013 at about 18:30 UT. We also compare our results with concurrent measurements from other solar soft x-ray instrumentation.

  2. Phenol-formaldehyde intumescent coating composition and coating prepared therefrom

    NASA Technical Reports Server (NTRS)

    Salyer, Ival O. (Inventor); Fox, Bernard L. (Inventor)

    1986-01-01

    Intumescent coatings which form a thick, uniform, fine celled, low density foam upon exposure to a high intensity heat flux or flame are disclosed, the invention coatings comprise phenolic resin prepolymer containing a blowing agent and a nucleating agent; in the preferred embodiments the coatings also contains a silicone surfactant, the coatings are useful in thermal and fire protection systems.

  3. Isomolybdate conversion coatings

    NASA Technical Reports Server (NTRS)

    Minevski, Zoran (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating solution and process forms a stable and corrosion-resistant layer on metal substrates or layers or, more preferably, on a boehmite layer or other base conversion coating. The conversion coating process involves contacting the substrate, layer or coating with an aqueous alkali metal isomolybdate solution in order to convert the surface of the substrate, layer or coating to a stable conversion coating. The aqueous alkali metal molybdates are selected from sodium molybdate (Na.sub.2 MoO.sub.4), lithium molybdate (Li.sub.2 MoO.sub.4), potassium molybdate (K.sub.2 MoO.sub.4), or combinations thereof, with the most preferred alkali metal molybdate being sodium molybdate. The concentration of alkali metal molybdates in the solution is preferably less than 5% by weight. In addition to the alkali metal molybdates, the conversion coating solution may include alkaline metal passivators selected from lithium nitrate (LiNO.sub.3), sodium nitrate (NaNO.sub.3), ammonia nitrate (NH.sub.4 NO.sub.3), and combinations thereof; lithium chloride, potassium hexafluorozirconate (K.sub.2 ZrF.sub.6) or potassium hexafluorotitanate (K.sub.2 TiF.sub.6).

  4. Functional relationship between CABIT, SAM and 14-3-3 binding domains of GAREM1 that play a role in its subcellular localization

    SciTech Connect

    Nishino, Tasuku; Matsunaga, Ryota; Konishi, Hiroaki

    2015-08-21

    GAREM1 (Grb2-associated regulator of Erk/MAPK1) is an adaptor protein that is involved in the epidermal growth factor (EGF) pathway. The nuclear localization of GAREM1 depends on the nuclear localization sequence (NLS), which is located at the N-terminal CABIT (cysteine-containing, all in Themis) domain. Here, we identified 14-3-3ε as a GAREM-binding protein, and its binding site is closely located to the NLS. This 14-3-3 binding site was of the atypical type and independent of GAREM phosphorylation. Moreover, the binding of 14-3-3 had an effect on the nuclear localization of GAREM1. Unexpectedly, we observed that the CABIT domain had intramolecular association with the C-terminal SAM (sterile alpha motif) domain. This association might be inhibited by binding of 14-3-3 at the CABIT domain. Our results demonstrate that the mechanism underlying the nuclear localization of GAREM1 depends on its NLS in the CABIT domain, which is controlled by the binding of 14-3-3 and the C-terminal SAM domain. We suggest that the interplay between 14-3-3, SAM domain and CABIT domain might be responsible for the distribution of GAREM1 in mammalian cells. - Highlights: • 14-3-3ε regulated the nuclear localization of GAREM1 as its binding partner. • The atypical 14-3-3 binding site of GAREM1 is located near the NLS in CABIT domain. • The CABIT domain had intramolecular association with the SAM domain in GAREM1. • Subcellular localization of GAREM1 is affected with its CABIT-SAM interaction.

  5. COATING URANIUM FROM CARBONYLS

    DOEpatents

    Gurinsky, D.H.; Storrs, S.S.

    1959-07-14

    Methods are described for making adherent corrosion resistant coatings on uranium metal. According to the invention, the uranium metal is heated in the presence of an organometallic compound such as the carbonyls of nickel, molybdenum, chromium, niobium, and tungsten at a temperature sufficient to decompose the metal carbonyl and dry plate the resultant free metal on the surface of the uranium metal body. The metal coated body is then further heated at a higher temperature to thermally diffuse the coating metal within the uranium bcdy.

  6. Advanced thermal barrier coating systems

    NASA Technical Reports Server (NTRS)

    Dorfman, M. R.; Reardon, J. D.

    1985-01-01

    Current state-of-the-art thermal barrier coating (TBC) systems consist of partially stabilized zirconia coatings plasma sprayed over a MCrAlY bond coat. Although these systems have excellent thermal shock properties, they have shown themselves to be deficient for a number of diesel and aircraft applications. Two ternary ceramic plasma coatings are discussed with respect to their possible use in TBC systems. Zirconia-ceria-yttria (ZCY) coatings were developed with low thermal conductivities, good thermal shock resistance and improved resistance to vanadium containing environments, when compared to the baseline yttria stabilized zirconia (YSZ) coatings. In addition, dense zirconia-titania-yttria (ZTY) coatings were developed with particle erosion resistance exceeding conventional stabilized zirconia coatings. Both coatings were evaluated in conjunction with a NiCr-Al-Co-Y2O3 bond coat. Also, multilayer or hybrid coatings consisting of the bond coat with subsequent coatings of zirconia-ceria-yttria and zirconia-titania-yttria were evaluated. These coatings combine the enhanced performance characteristics of ZCY with the improved erosion resistance of ZTY coatings. Improvement in the erosion resistance of the TBC system should result in a more consistent delta T gradient during service. Economically, this may also translate into increased component life simply because the coating lasts longer.

  7. Aluminum phosphate coatings

    DOEpatents

    Sambasivan, Sankar; Steiner, Kimberly A.; Rangan, Krishnaswamy K.

    2007-12-25

    Aluminophosphate compounds and compositions as can be used for substrate or composite films and coating to provide or enhance, without limitation, planarization, anti-biofouling and/or anti-microbial properties.

  8. POWDER COAT APPLICATIONS

    EPA Science Inventory

    The report discusses an investigation of critical factors that affect the use of powder coatings on the environment, cost, quality, and production. The investigation involved a small business representative working with the National Defense Center for Environmental Excellence (ND...

  9. 'Mazatzal's' Many Coats

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This close-up image taken by the Mars Exploration Rover Spirit's microscopic imager shows a section of the hole drilled into the rock dubbed 'Mazatzal' after the hole was ground for a second time. The first drilling by the rover's rock abrasion tool left an incomplete hole, so a second one was performed. The blue arrow points to leftover portions of the dark rind that coats Mazatzal and the scrape marks left by the rock abrasion tool. The yellow arrow highlights the bright edges surrounding the leftover rind. The crack in the rock may have once contained fluids out of which minerals precipitated along its walls (red arrows). Mazatzal is a highly coated rock, containing at least four 'cake layers': a top coat of dust, a pinking coating, a dark rind and its true interior. The observed area is 3 centimeters (1.2 inches) across. This image was taken on sol 85.

  10. Multilayer optical dielectric coating

    DOEpatents

    Emmett, John L.

    1990-01-01

    A highly damage resistant, multilayer, optical reflective coating includes alternating layers of doped and undoped dielectric material. The doping levels are low enough that there are no distinct interfaces between the doped and undoped layers so that the coating has properties nearly identical to the undoped material. The coating is fabricated at high temperature with plasma-assisted chemical vapor deposition techniques to eliminate defects, reduce energy-absorption sites, and maintain proper chemical stoichiometry. A number of differently-doped layer pairs, each layer having a thickness equal to one-quarter of a predetermined wavelength in the material are combined to form a narrowband reflective coating for a predetermined wavelength. Broadband reflectors are made by using a number of narrowband reflectors, each covering a portion of the broadband.

  11. Super Thin Ceramic Coatings

    NASA Video Gallery

    New technology being developed at NASA's Glenn Research Center creates super thin ceramic coatings on engine components. The Plasma Spray – Physical Vapor Deposition (PS-PVD) rig uses a powerful ...

  12. Preventing Cracking of Anodized Coatings

    NASA Technical Reports Server (NTRS)

    He, Charles C.; Heslin, Thomas M.

    1995-01-01

    Anodized coatings have been used as optical and thermal surfaces in spacecraft. Particulate contamination from cracked coatings is a concern for many applications. The major cause for the cracking is the difference in the coefficient of thermal expansion between the oxide coatings and the aluminum substrate. The loss of water when the coating is exposed to a vacuum also could induce cracking of the coating. Hot-water sealing was identified as the major cause for the cracking of the coatings because of the large temperature change when the parts were immersed in boiling water and the water was absorbed in the coating. when the hot-water sealing process was eliminated, the cracking resistance of the anodized coatings was greatly improved. Also, it was found that dyed black coatings were more susceptible than clear coatings to cracking during thermo-vacuum cyclings.

  13. Friction surfaced Stellite6 coatings

    SciTech Connect

    Rao, K. Prasad; Damodaram, R.; Rafi, H. Khalid; Ram, G.D. Janaki; Reddy, G. Madhusudhan; Nagalakshmi, R.

    2012-08-15

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: Black-Right-Pointing-Pointer Stellite6 used as coating material for friction surfacing. Black-Right-Pointing-Pointer Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. Black-Right-Pointing-Pointer Finer and uniformly distributed carbides in friction surfaced coatings. Black-Right-Pointing-Pointer Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  14. Nanostructured Superhydrophobic Coatings

    SciTech Connect

    2009-03-01

    This factsheet describes a research project that deals with the nanostructured superhydrophobic (SH) powders developed at ORNL. This project seeks to (1) improve powder quality; (2) identify binders for plastics, fiberglass, metal (steel being the first priority), wood, and other products such as rubber and shingles; (3) test the coated product for coating quality and durability under operating conditions; and (4) application testing and production of powders in quantity.

  15. Nanostructured Carbon Coatings

    DTIC Science & Technology

    2000-01-01

    carbon coatings and explores a very broad range of potentially important carbon nanostructures that may be used in future technologies. A new method ...for the synthesis of nanostructured carbon coatings on the surface of SiC and other metal carbides is described. This method is accomplished through the...With the fall in cost of fullerene powders, this method may become important in the future as a method to produce nanocrystalline diamond free of metal

  16. Spin coating apparatus

    DOEpatents

    Torczynski, John R.

    2000-01-01

    A spin coating apparatus requires less cleanroom air flow than prior spin coating apparatus to minimize cleanroom contamination. A shaped exhaust duct from the spin coater maintains process quality while requiring reduced cleanroom air flow. The exhaust duct can decrease in cross section as it extends from the wafer, minimizing eddy formation. The exhaust duct can conform to entrainment streamlines to minimize eddy formation and reduce interprocess contamination at minimal cleanroom air flow rates.

  17. Materials Coating Techniques

    DTIC Science & Technology

    1980-03-01

    properties of the coating layers and their interaction with the bulk material will be considered. Lectures will also cover the behaviour of coated parts...stability etc. Finally, available techniques for the analysis and non-destructive evaluation of the composition. properties and soundness of the...provide stiffness or flexibility, and to carry the applied loads without macroscopic failure. Such properties are associated with the bulk material of

  18. METAL COATING BATHS

    DOEpatents

    Robinson, J.W.

    1958-08-26

    A method is presented for restoring the effectiveness of bronze coating baths used for hot dip coating of uranium. Such baths, containing a high proportion of copper, lose their ability to wet uranium surfaces after a period of use. The ability of such a bath to wet uranium can be restored by adding a small amount of metallic aluminum to the bath, and skimming the resultant hard alloy from the surface.

  19. Ceramic electrolyte coating methods

    DOEpatents

    Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

    2004-10-12

    Processes for preparing aqueous suspensions of a nanoscale ceramic electrolyte material such as yttrium-stabilized zirconia. The invention also includes a process for preparing an aqueous coating slurry of a nanoscale ceramic electrolyte material. The invention further includes a process for depositing an aqueous spray coating slurry including a ceramic electrolyte material on pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

  20. Multilayer thermal barrier coating systems

    DOEpatents

    Vance, Steven J.; Goedjen, John G.; Sabol, Stephen M.; Sloan, Kelly M.

    2000-01-01

    The present invention generally describes multilayer thermal barrier coating systems and methods of making the multilayer thermal barrier coating systems. The thermal barrier coating systems comprise a first ceramic layer, a second ceramic layer, a thermally grown oxide layer, a metallic bond coating layer and a substrate. The thermal barrier coating systems have improved high temperature thermal and chemical stability for use in gas turbine applications.