Sample records for aa2024-t35 joints aa2024-t35

  1. An investigation into the mechanism for enhanced mechanical properties in friction stir welded AA2024-T3 joints coated with cold spraying

    NASA Astrophysics Data System (ADS)

    Li, N.; Li, W. Y.; Yang, X. W.; Feng, Y.; Vairis, A.

    2018-05-01

    Using cold spraying (CS), a surface layer with a modified microstructure and enhanced mechanical properties was formed on a 3.2 mm thick friction stir welded (FSWed) AA2024-T3 joint. The combined effect of "shot peening effect (SPE)" and "heat flow effect (HFE)" during CS were used to enhance joint mechanical properties. The microstructure evolution of the FSWed AA2024-T3 joints in the surface layer following CS coatings and their effect on mechanical properties were systematically characterized with electron back-scattered diffraction, transmission electron microscopy, differential scanning calorimetry and mechanical tests. Based on these experiments, a grain refinement, finer and more S phases, and improved amount of Guinier-Preston-Bagaryatsky (GPB) zones produced by CS treatments are proposed. The deposition of aluminum coating on the joint, lead to hardness recovery in the stir zone and the development of two low hardness zones as the density of GPB increased. The tensile properties of FSWed AA2024-T3 joints improved with the application of the aluminum coatings. Experiments and analysis of the enhanced mechanical properties mechanism indicate that SPE with a high plastic deformation and HFE with an intensive heat flow are necessary for the production of refined grains and increased numbers of GPB zones.

  2. Characterization of AA2024-T3 by scanning Kelvin probe force microscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schmutz, P.; Frankel, G.S.

    1998-07-01

    Volta potential mapping of AA2024-T3 on surfaces was performed with an atomic force microscope. A linear relation was found between the Volta potential measured in air and the corrosion potential in aqueous solution for a range of pure metal samples, indicating that this potential is a measurement of the practical nobility of the surface. Large differences in the Volta potential of intermetallic particles in AA2024-T3 and the matrix phase resulted in a potential map with high contrast that clearly identifies the location of the particles. All intermetallic particles, including the Mg-containing S-phase particles, had a Volta potential noble to thatmore » of the matrix. Surface films on the particles and the matrix were found to have strong effects on the potential, and probably explain the noble nature of the Mg-containing particles, which have been reported to be active to the matrix in solution. The effect of these surface films was examined by refreshing the sample surface using different techniques. Lateral heterogeneities in certain intermetallic particles were also revealed.« less

  3. Wear behaviors of pure aluminum and extruded aluminum alloy (AA2024-T4) under variable vertical loads and linear speeds

    NASA Astrophysics Data System (ADS)

    Jung, Jeki; Oak, Jeong-Jung; Kim, Yong-Hwan; Cho, Yi Je; Park, Yong Ho

    2017-11-01

    The aim of this study was to investigate the transition of wear behavior for pure aluminum and extruded aluminum alloy 2024-T4 (AA2024-T4). The wear test was carried using a ball-on-disc wear testing machine at various vertical loads and linear speeds. The transition of wear behaviors was analyzed based on the microstructure, wear tracks, wear cross-section, and wear debris. The critical wear rates for each material are occurred at lower linear speed for each vertical load. The transition of wear behavior was observed in which abrasion wears with the generation of an oxide layer, fracture of oxide layer, adhesion wear, severe adhesion wear, and the generation of seizure occurred in sequence. In case of the pure aluminum, the change of wear debris occurred in the order of blocky, flake, and needle-like debris. Cutting chip, flake-like, and coarse flake-like debris was occurred in sequence for the extruded AA2024-T4. The transition in the wear behavior of extruded AA2024-T4 occurred slower than in pure aluminum.

  4. Microstructure Stability During Creep of Friction Stir Welded AA2024-T3 Alloy

    NASA Astrophysics Data System (ADS)

    Regev, Michael; Rashkovsky, Tal; Cabibbo, Marcello; Spigarelli, Stefano

    2018-01-01

    The poor weldability of the AA2024 aluminum alloy limits its use in industrial applications. Because friction stir welding (FSW) is a non-fusion welding process, it seems to be a promising solution for welding this alloy. In the current study, FSW was applied to butt weld AA2024-T3 aluminum alloy plates. Creep tests were conducted at 250 and at 315 °C on both the parent material and the friction stir welded specimens. The microstructures of the welded and non-welded AA2024-T3 specimens before and after the creep tests were studied and compared. A comprehensive transmission electron microscopy study together with a high-resolution scanning electron microscopy study and energy-dispersive x-ray spectroscopy analysis was conducted to investigate the microstructure stability. The parent material seems to contain two kinds of Cu-rich precipitates—coarse precipitates of a few microns each and uniformly dispersed fine nanosized precipitates. Unlike the parent material, the crept specimens were found to contain the two kinds of precipitates mentioned above together with platelet-like precipitates. In addition, extensive decoration of the grain boundaries with precipitates was clearly observed in the crept specimens. Controlled aging experiments for up to 280 h at the relevant temperatures were conducted on both the parent material and the welded specimens in order to isolate the contribution of exposure to high temperatures to the microstructure changes. TEM study showed the development of dislocation networks into a cellular dislocation structure in the case of the parent metal. Changes in the dislocation structure as a function of the creep strain and the FSW process were recorded. A detailed creep data analysis was conducted, taking into account the instability of the microstructure.

  5. Blister Test for Measurements of Adhesion and Adhesion Degradation of Organic Polymers on AA2024-T3

    NASA Astrophysics Data System (ADS)

    Rincon Troconis, Brendy Carolina

    A key parameter for the performance of corrosion protective coatings applied to metals is adhesion. Surface preparation prior to coating application is known to be critical, but there is a lack of understanding of what controls adhesion. Numerous techniques have been developed in the last decades to measure the adhesion strength of coatings to metals. Nonetheless, they are generally non-quantitative, non-reproducible, performed in dry conditions, or overestimate adhesion. In this study, a quantitative and reproducible technique, the Blister Test (BT), is used. The BT offers the ability to study the effects of a range of parameters, including the presence or absence of a wetting liquid, and simulates the stress situation in the coating/substrate interface. The effects of roughness and surface topography were studied by the BT and Optical Profilometry, using AA2024-T3 substrates coated with polyvinyl butyral (PVB). Random abrasion generated a surface with lower average roughness than aligned abrasion due to the continual cross abrasion of the grooves. The BT could discern the effects of different mechanical treatments. An adhesion strength indicator was defined and found to be a useful parameter. The effectiveness of standard adhesion techniques such as ASTM D4541 (Pull-off Test) and ASTM D3359 (Tape Test) was compared to the BT. Also, different attempts to measure adhesion and adhesion degradation of organic polymers to AA2024-T3 were tested. The pull-off test does not produce adhesive failure across the entire interface, while the tape test is a very qualitative technique and does not discern between the effects of different coating systems on the adhesion performance. The BT produces adhesive failure of the primer studied, is very reproducible, and is able to rank different coating systems. Therefore, it was found to be superior to the others. The approaches tested for adhesion degradation were not aggressive enough to have a measurable effect. The effects of

  6. Comparison of fatigue crack growth of riveted and bonded aircraft lap joints made of Aluminium alloy 2024-T3 substrates - A numerical study

    NASA Astrophysics Data System (ADS)

    Pitta, S.; Rojas, J. I.; Crespo, D.

    2017-05-01

    Aircraft lap joints play an important role in minimizing the operational cost of airlines. Hence, airlines pay more attention to these technologies to improve efficiency. Namely, a major time consuming and costly process is maintenance of aircraft between the flights, for instance, to detect early formation of cracks, monitoring crack growth, and fixing the corresponding parts with joints, if necessary. This work is focused on the study of repairs of cracked aluminium alloy (AA) 2024-T3 plates to regain their original strength; particularly, cracked AA 2024-T3 substrate plates repaired with doublers of AA 2024-T3 with two configurations (riveted and with adhesive bonding) are analysed. The fatigue life of the substrate plates with cracks of 1, 2, 5, 10 and 12.7mm is computed using Fracture Analysis 3D (FRANC3D) tool. The stress intensity factors for the repaired AA 2024-T3 plates are computed for different crack lengths and compared using commercial FEA tool ABAQUS. The results for the bonded repairs showed significantly lower stress intensity factors compared with the riveted repairs. This improves the overall fatigue life of the bonded joint.

  7. Inhibition of Tryptophan on AA 2024 in Chloride-Containing Solutions

    NASA Astrophysics Data System (ADS)

    Li, Xing; Xiang, Bin; Zuo, Xiu-Li; Wang, Qin; Wei, Zi-Dong

    2011-03-01

    The inhibitory effects of tryptophan on the corrosion of AA 2024 in 1 M HCl, 20% (wt.%) CaCl2, and 3.5% (wt.%) NaCl solutions were investigated via polarization techniques, electrochemical impedance spectroscopy, and weight loss methods. The scanning electron microscope technique was employed to observe corrosion morphology. The results suggest that AA 2024 was corroded in these three corrosive media to some extent and that tryptophan can significantly inhibit the corrosion of aluminum alloys. The inhibition efficiency (η) increased with increasing concentrations of tryptophan, and the best inhibition efficiency exhibited was about 87% in 1 M HCl solution with 0.008 M tryptophan. Tryptophan acted as a cathodic corrosion inhibitor and affected the hydrogen evolution reaction, which was the main electrode reaction in the 1 M HCl solution. In solutions with 20% CaCl2 and 3.5% NaCl, tryptophan was adsorbed onto anodic areas, thus increasing the activation energy of the interface reaction as an anodic corrosion inhibitor. The Dmol3 program of Material Studio 4.0 was used to obtain the optimized geometry of the tryptophan inhibitor and some quantum-chemical parameters. Front orbital distributions and Fukui indices indicate that the molecular active reaction zones were located in the indole ring of tryptophan.

  8. The corrosion protection of AA2024-T3 aluminium alloy by leaching of lithium-containing salts from organic coatings.

    PubMed

    Visser, Peter; Liu, Yanwen; Zhou, Xiaorong; Hashimoto, Teruo; Thompson, George E; Lyon, Stuart B; van der Ven, Leendert G J; Mol, Arjan J M C; Terryn, Herman A

    2015-01-01

    Lithium carbonate and lithium oxalate were incorporated as leachable corrosion inhibitors in model organic coatings for the protection of AA2024-T3. The coated samples were artificially damaged with a scribe. It was found that the lithium-salts are able to leach from the organic coating and form a protective layer in the scribe on AA2024-T3 under neutral salt spray conditions. The present paper shows the first observation and analysis of these corrosion protective layers, generated from lithium-salt loaded organic coatings. The scribed areas were examined by scanning and transmission electron microscopy before and after neutral salt spray exposure (ASTM-B117). The protective layers typically consist of three different layered regions, including a relatively dense layer near the alloy substrate, a porous middle layer and a flake-shaped outer layer, with lithium uniformly distributed throughout all three layers. Scanning electron microscopy and white light interferometry surface roughness measurements demonstrate that the formation of the layer occurs rapidly and, therefore provides an effective inhibition mechanism. Based on the observation of this work, a mechanism is proposed for the formation of these protective layers.

  9. Effects of aging temperature and time on the corrosion protection provided by trivalent chromium process coatings on AA2024-T3.

    PubMed

    Li, Liangliang; Swain, Greg M

    2013-08-28

    The effects of aging temperature and time on the physical structure of and corrosion protection provided by trivalent chromium process (TCP) coatings on AA2024-T3 are reported. The TCP coating forms a partially blocking barrier layer on the alloy surface that consists of hydrated channels and or defects. It is through these channels and defects that ions and dissolved O2 can be transported to small areas of the underlying alloy. Reactions initiate at these sites, which can ultimately lead to undercutting of the coating and localized corrosion. We tested the hypothesis that collapsing the channels and or reducing the number of defects in the coating might be possible through post-deposition heat treatment, and that this would enhance the corrosion protection provided by the coating. This was tested by aging the TCP-coated AA2024 alloys in air overnight at room temperature (RT), 55, 100, or 150 °C. The TCP coating became dehydrated and thinner at the high temperatures (55 and 100 °C). This improved the corrosion protection as evidenced by a 2× increase in the charge transfer resistance. Aging at 150 °C caused excessive coating dehydration and shrinkage. This led to severe cracking and detachment of the coating from the surface. The TCP-coated AA2024 samples were also aged in air at RT from 1 to 7 days. There was no thinning of the coating, but the corrosion protection was enhanced with a longer aging period as evidenced by a 4× increase in the charge transfer resistance. The coating became more hydrophobic after aging at elevated temperature (up to 100 °C) and with aging time at RT as evidenced by an increased water contact angle from 7 to 100 °C.

  10. Corrosion study of AA2024-T3 by scanning Kelvin probe force microscopy and in situ atomic force microscopy scratching

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schmutz, P.; Frankel, G.S.

    1998-07-01

    The localized corrosion of AA2024-T3, and the behavior of intermetallic particles in particular, were studied using different capabilities of the atomic force microscope (AFM). The role of intermetallic particles in determining the locations and rates of localized corrosion was determined using scanning Kelvin probe force microscopy in air after exposure to chloride solutions. Al-Cu-Mg particles, which have a noble Volta potential in air because of an altered surface film, are actively dissolved in chloride solution after a certain induction time. Al-Cu(Fe, Mn) particles are heterogeneous in nature and exhibit nonuniform dissolution in chloride solution as well as trenching of themore » matrix around the particles. Light scratching of the surface by rastering with the AFM tip in contact mode in chloride solution results in accelerated dissolution of both pure Al and alloy 2024-T3. The abrasion associated with contact AFM in situ resulted in the immediate dissolution of the Al-Cu-Mg particles because of a destabilization of the surface film.« less

  11. A Bottom-Up Optimization Approach for Friction Stir Welding Parameters of Dissimilar AA2024-T351 and AA7075-T651 Alloys

    NASA Astrophysics Data System (ADS)

    Anil Kumar, K. S.; Murigendrappa, S. M.; Kumar, Hemantha

    2017-07-01

    In the present study, optimum friction stir weld parameters such as plunge depth, tool rotation speed and traverse speed for butt weld of dissimilar aluminum alloy plates, typically 2024-T351 and 7075-T651, are investigated using a bottom-up approach. In the approach, optimum FSW parameters are achieved by varying any one parameter for every trial while remaining parameters are kept constant. The specimens are extracted from the friction stir-welded plates for studying the tensile, hardness and microstructure properties. Optimum friction stir weld individual parameters are selected based on the highest ultimate tensile strength of the friction stir-welded butt joint specimens produced by varying in each case one parameter and keeping the other two constant. The microstructure samples were investigated for presence of defects, grain refinement at the weld nugget (WN), bonding between the two materials and interface of WN, TMAZ (thermomechanically affected zone) of both advancing and retreating sides of the dissimilar joints using optical microscopy and scanning electron microscopy analyses. In the experimental investigations, the optimum FSW parameters such as plunge depth, 6.2 mm, rotation speed, 650 rpm and traverse speed of 150 mm/min result in ultimate tensile strength, 435 MPa, yield strength, 290 MPa, weld joint efficiency, 92% and maximum elongation, 13%. The microstructure of optimized sample in the WN region revealed alternate lamellae material flow pattern with better metallurgical properties, defect free and very fine equiaxed grain size of about 3-5 µm.

  12. 10 CFR 35.2024 - Records of authority and responsibilities for radiation protection programs.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Records of authority and responsibilities for radiation protection programs. 35.2024 Section 35.2024 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2024 Records of authority and responsibilities for radiation protection programs. (a...

  13. 10 CFR 35.2024 - Records of authority and responsibilities for radiation protection programs.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Records of authority and responsibilities for radiation protection programs. 35.2024 Section 35.2024 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2024 Records of authority and responsibilities for radiation protection programs. (a...

  14. 10 CFR 35.2024 - Records of authority and responsibilities for radiation protection programs.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Records of authority and responsibilities for radiation protection programs. 35.2024 Section 35.2024 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2024 Records of authority and responsibilities for radiation protection programs. (a...

  15. 10 CFR 35.2024 - Records of authority and responsibilities for radiation protection programs.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Records of authority and responsibilities for radiation protection programs. 35.2024 Section 35.2024 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2024 Records of authority and responsibilities for radiation protection programs. (a...

  16. 10 CFR 35.2024 - Records of authority and responsibilities for radiation protection programs.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Records of authority and responsibilities for radiation protection programs. 35.2024 Section 35.2024 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2024 Records of authority and responsibilities for radiation protection programs. (a...

  17. Development of 2024 AA-Yttrium composites by Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Vidyasagar, CH S.; Karunakar, D. B.

    2018-04-01

    The method of fabrication of MMNCs is quite a challenge, which includes advanced processing techniques like Spark Plasma Sintering (SPS), etc. The objective of the present work is to fabricate aluminium based MMNCs with the addition of small amounts of yttrium using Spark Plasma Sintering and to evaluate their mechanical and microstructure properties. Samples of 2024 AA with yttrium ranging from 0.1% to 0.5 wt% are fabricated by Spark Plasma Sintering (SPS). Hardness of the samples is determined using Vickers hardness testing machine. The metallurgical characterization of the samples is evaluated by Optical Microscopy (OM), Field Emission Scanning Electron Microscopy (FE-SEM). Unreinforced 2024 AA sample is also fabricated as a benchmark to compare its properties with those of the composite developed. It is found that the yttrium addition increases the above mentioned properties by altering the precipitation kinetics and intermetallic formation to some extent and then decreases gradually when yttrium wt% increases beyond 0.3 wt%. High density (˂ 99.75) is achieved in the samples and highest hardness achieved is 114 Hv, fabricated by spark plasma sintering and uniform distribution of yttrium is observed.

  18. 40 CFR 35.2024 - Combined sewer overflows.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works § 35.2024 Combined sewer... project priority list, it addresses impaired uses in priority water quality areas which are due to the... must demonstrate to the Administrator that the water quality goals of the Act will not be achieved...

  19. 40 CFR 35.2024 - Combined sewer overflows.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works § 35.2024 Combined sewer... project priority list, it addresses impaired uses in priority water quality areas which are due to the... must demonstrate to the Administrator that the water quality goals of the Act will not be achieved...

  20. 40 CFR 35.2024 - Combined sewer overflows.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works § 35.2024 Combined sewer... project priority list, it addresses impaired uses in priority water quality areas which are due to the... must demonstrate to the Administrator that the water quality goals of the Act will not be achieved...

  1. Effect of wear parameters on dry sliding behavior of Fly Ash/SiC particles reinforced AA 2024 hybrid composites

    NASA Astrophysics Data System (ADS)

    Bhaskar Kurapati, Vijaya; Kommineni, Ravindra

    2017-09-01

    In the present work AA 2024 alloy reinforced with mixtures of SiC and Fly Ash (FA) particles of 70 µm (5, 10 and 15 wt. %) are fabricated using the stir casting method. Both reinforcements are added in equal weight proportions. The wear test specimens are prepared from both the alloy and composite castings in the dimensions of Ф 4 mm and 30 mm lengths by the wire cut EDM process. The dry sliding wear properties of the prepared composites at room temperature are estimated by pin-on-disc wear testing equipment. The wear characteristics of the composites are studied by conducting the dry sliding wear test over loads of 0.5 Kgf, 1.0 Kgf, 1.5 Kgf, a track diameter of 60 mm and sliding times of 15 min, 30 min, 45min. The experimental results shows that the wear decreases with an increase in the weight percentage of FA and SiC particles in the matrix. Additionally wear increases with an increase in load and sliding time. Further, it is found that the wear resistance of the AA2024-Hybrid composites is higher than that of the AA2024 matrix.

  2. Influence of laser parameters in surface texturing of Ti6Al4V and AA2024-T3 alloys

    NASA Astrophysics Data System (ADS)

    Ahuir-Torres, J. I.; Arenas, M. A.; Perrie, W.; de Damborenea, J.

    2018-04-01

    Laser texturing can be used for surface modification of metallic alloys in order to improve their properties under service conditions. The generation of textures is determined by the relationship between the laser processing parameters and the physicochemical properties of the alloy to be modified. In the present work the basic mechanism of dimple generation is studied in two alloys of technological interest, titanium alloy Ti6Al4V and aluminium alloy AA2024-T3. Laser treatment was performed using a pulsed solid state Nd: Vanadate (Nd: YVO4) laser with a pulse duration of 10 ps, operating at a wavelength of 1064 nm and 5 kHz repetition rate. Dimpled surface geometries were generated through ultrafast laser ablation while varying pulse energy between 1 μJ and 20 μJ/pulse and with pulse numbers from 10 to 200 pulses per spot. In addition, the generation of Laser Induced Periodic Surface Structures (LIPSS) nanostructures in both alloys, as well as the formation of random nanostructures in the impact zones are discussed.

  3. Effect of Preexisting Corrosion on Fatigue Cracking of Aluminum Alloys 2024-T3 and 7075-T6

    DTIC Science & Technology

    1995-08-01

    alloys 2024 -T3 and 7075-T6. It was determined that preexisting corrosion has a detrimental effect on the fatigue life of aluminum alloys 2024 -T3 and...following conclusions were drawn: 1. Preexisting corrosion has a detrimental effect on the fatigue life of aluminum alloys 2024 -T3 and 7075-T6. The...corrosion has a detrimental effect on the fatigue life of aluminum alloys

  4. Corrosion behavior of ultrafine-grained AA2024 aluminum alloy produced by cryorolling

    NASA Astrophysics Data System (ADS)

    Laxman Mani Kanta, P.; Srivastava, V. C.; Venkateswarlu, K.; Paswan, Sharma; Mahato, B.; Das, Goutam; Sivaprasad, K.; Krishna, K. Gopala

    2017-11-01

    The objectives of this study were to produce ultrafine-grained (UFG) AA2024 aluminum alloy by cryorolling followed by aging and to evaluate its corrosion behavior. Solutionized samples were cryorolled to 85% reduction in thickness. Subsequent aging resulted in a UFG structure with finer precipitates of Al2CuMg in the cryorolled alloy. The (1) solutionized and (2) solutionized and cryorolled samples were uniformly aged at 160°C/24 h and were designated as CGPA and CRPA, respectively; these samples were subsequently subjected to corrosion studies. Potentiodynamic polarization studies in 3.5wt% NaCl solution indicated an increase in corrosion potential and a decrease in corrosion current density for CRPA compared to CGPA. In the case of CRPA, electrochemical impedance spectroscopic studies indicated the presence of two complex passive oxide layers with a higher charge transfer resistance and lower mass loss during intergranular corrosion tests. The improved corrosion resistance of CRPA was mainly attributed to its UFG structure, uniform distribution of fine precipitates, and absence of coarse grain-boundary precipitation and associated precipitate-free zones as compared with the CGPA alloy.

  5. Mechanical Properties of Shock Treated Aluminium Alloy Al 2024-T4

    NASA Astrophysics Data System (ADS)

    Joshi, K. D.; Mukhopadhyay, A. K.; Dey, A.; Rav, Amit S.; Biswas, S.; Gupta, Satish C.

    2012-07-01

    Plate impact experiment has been carried out on Al 2024-T4 alloy using single stage gas gun. The dynamic yield strength and spall strength of Al 2024-T4 sample has been determined to be 0.35 GPa and 1.43 GPa, respectively, from free surface velocity history measured using VISAR. The sample recovered after unloading from peak shock pressure of 4.4 GPa along with an unshocked sample is analyzed for mechanical properties using nano-indentation and scanning electron microscopy (SEM). The nano-indentation measurements reveal that the hardness and Young's modulus for unshocked sample remains unchanged as a function of load (equivalently depth), however, the same for shocked sample decreases monotonically with increase of load up to ~40 mN and on further increase of load it remains unchanged, suggesting the (i) increase in hardness of shock loaded sample; (ii) the increase in hardness is limited to certain depth, which in our case is 845.12 ± 43.16 nm.

  6. Characterization of lap joints laser beam welding of thin AA 2024 sheets with Yb:YAG disk-laser

    NASA Astrophysics Data System (ADS)

    Caiazzo, Fabrizia; Alfieri, Vittorio; Cardaropoli, Francesco; Sergi, Vincenzo

    2012-06-01

    Lap joints obtained by overlapping two plates are widely diffused in aerospace industry. Nevertheless, because of natural aging, adhesively bonded and riveted aircraft lap joints may be affected by cracks from rivets, voids or corrosion. Friction stir welding has been proposed as a valid alternative, although large heat affected zones are produced both in the top and the bottom plate due to the pin diameter. Interest has therefore been shown in studying laser lap welding as the laser beam has been proved to be competitive since it allows to concentrate the thermal input and increases productivity and quality. Some challenges arise as a consequence of aluminum low absorptance and high thermal conductivity; furthermore, issues are due to metallurgical challenges such as both micro and macro porosity formation and softening in the fused zone. Welding of AA 2024 thin sheets in a lap joint configuration is discussed in this paper: tests are carried out using a recently developed Trumpf TruDisk 2002 Yb:YAG disk-laser with high beam quality which allows to produce beads with low plates distortion and better penetration. The influence of the processing parameters is discussed considering the fused zone extent and the bead shape. The porosity content as well as the morphological features of the beads have been examined.

  7. Tensile Properties of Friction Stir Welded Joints of AA 2024-T6 Alloy at Different Welding Speeds

    NASA Astrophysics Data System (ADS)

    Avula, Dhananjayulu; Devuri, Venkateswarlu; Cheepu, Muralimohan; Dwivedi, Dheerendra Kumar

    2018-03-01

    The influence of welding speed on the friction stir welded joint properties of hardness, tensile properties, defects and microstructure characterization are studied in the present study. The friction stir welding was conducted on AA2014-T6 heat treated alloy with 5 mm thickness plate in butt joint configuration. The welding speed was varied from 8 mm/min to 120 mm/min at the fixed travel speed and load conditions. It is observed that the welding speeds at higher rate with wide range can be possible to weld this alloy at higher rates of tool revolution suggesting that the inherent capability of friction stir welding technique for aluminum 2014 alloys. The strength of the joints gradually increases with enhancing of welding speed. The micro structural observations exhibited the formation of equiaxed grains in the stir zone and slightly in the thermo-mechanically affected zone. In addition, the size of the grains decreases with increase in welding speed owing to the presence of low heat input. Hence the hardness of the joints slightly increased in the stir zones over the other zones of the weld nugget. The joint strength initially increases with the welding speed and starts to decreases after reaching to the maximum value. The relationship between the welding conditions and friction stir welded joint properties has been discussed.

  8. Interfacial and Mechanical Behavior of AA5456 Filling Friction-Stir-Welded Lap Joints Using Similar and Dissimilar Pins

    NASA Astrophysics Data System (ADS)

    Behmand, Saleh Alaei; Mirsalehi, Seyyed Ehsan; Omidvar, Hamid; Safarkhanian, Mohammad Ali

    2016-10-01

    In this article, filling friction stir welding (FFSW) of the remaining exit holes of AA5456 alloy friction-stir-welded lap joints was studied. For this purpose, the influences of different rotating speeds, holding times, and pin materials, AA5456 and AA2024, on the metallurgical structure and joint strength were investigated. The observations showed that defect-free lap joints are successfully obtainable by this method using similar and dissimilar consumable pins. The results indicated that the higher rotating speed and holding time adversely affect the weld performance. The best result was achieved for 30 seconds holding time, 500 rpm rotating speed, and AA2024 consumable pin. In this condition, a lap shear strength of 10 pct higher than that of the nonfilled joint, equivalent to about 94 pct of the original defect-free FSW joint, was obtained, whereas the GTAW filled joint showed only approximately 87 pct of the continuous FSW joint strength.

  9. Sol-gel hybrid films based on organosilane and montmorillonite for corrosion inhibition of AA2024.

    PubMed

    Dalmoro, V; dos Santos, J H Z; Armelin, E; Alemán, C; Azambuja, D S

    2014-07-15

    The present work reports the production of films on AA2024-T3 composed of vinyltrimethoxysilane (VTMS)/tetraethylorthosilicate (TEOS) with incorporation of montmorillonite (sodium montmorillonite and montmorillonite modified with quaternary ammonium salt, abbreviated Na and 30B, respectively), generated by the sol-gel process. According to FT-IR analyses the incorporation of montmorillonite does not affect silica network. Electrochemical characterization was performed by electrochemical impedance spectroscopy measurement in 0.05 mol L(-1) NaCl solution. Results indicate that montmorillonite incorporation improves the corrosion protection compared to the non-modified system. Scanning electron microscopy micrographs reveal that high concentrations of montmorillonite provide agglomerations on the metallic surface, which is in detriment of the anticorrosive performance. The VTMS/TEOS/30B films with the lowest concentration (22 mg L(-1)) of embedded clay provide the highest corrosion protection. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Adhesion of epoxy primer to hydrotalcite conversion coated AA2024

    NASA Astrophysics Data System (ADS)

    Leggat, Robert Benton, III

    Hydrotalcite-based (HT) conversion coatings are being developed as an environmentally benign alternative to chromate conversion coatings (CCC). Accelerated exposure tests were conducted on epoxy primed, HT-modified AA2024 to gauge service performance. HT-based conversion coatings did not perform as well as the CCC when used with an epoxy primer. The current HT chemistries are optimized for stand-alone corrosion protection, however additional research into the primer/HT interactions is necessary before they can be implemented within a coating scheme. The relative contribution of mechanical and physico-chemical interactions in controlling adhesion has been investigated in this study. Practical adhesion tests were used to assess the dry and wet bond strength of epoxy primer on HT coatings using the pull-off tensile strength (POTS) as the figure of merit. The practical adhesion of HT coated samples generally fell between that observed for the CCC and bare AA2024. Laboratory testing was done to assess the physical and chemical properties of HT coatings. Contact angle measurements were performed using powders representative of different HT chemistries to evaluate the dispersive and acid-base character of the surface. The wet POTS correlated with the electrodynamic (dipole + dispersive) parameter of the surface tension. The HT surfaces were found to be predominantly basic. Given the basicity of epoxy, these results indicate that increasing the acidic character of HT coatings may increase the adhesion performance. This was supported by electrokinetic measurements in which the dry POTS was found to increase with decreasing conversion coating iso-electric point. The correlations with the dry and wet state adhesion are interpreted as indicating that dry state adhesion is optimized by minimizing unfavorable polar interactions between the basic epoxy and HT interfaces. Wet state adhesion, where polar interactions are disrupted, is dictated by non-polar bonding. FTIR

  11. A computational study of low-head direct chill slab casting of aluminum alloy AA2024

    NASA Astrophysics Data System (ADS)

    Hasan, Mainul; Begum, Latifa

    2016-04-01

    The steady state casting of an industrial-sized AA2024 slab has been modeled for a vertical low-head direct chill caster. The previously verified 3-D CFD code is used to investigate the solidification phenomena of the said long-range alloy by varying the pouring temperature, casting speed and the metal-mold contact heat transfer coefficient from 654 to 702 °C, 60-180 mm/min, and 1.0-4.0 kW/(m2 K), respectively. The important predicted results are presented and thoroughly discussed.

  12. Investigation of corrosion protection performance of sol-gel surface treatments on AA2024-T3

    NASA Astrophysics Data System (ADS)

    Voevodin, Natalia Nikolajevna

    The dissertation research project addresses the technologically important problem of replacement of chromate based coatings for corrosion protection of aircraft. A review of corrosion processes in high-strength aluminum alloys indicated that the strengthening intermetallic precipitates provide local cathodic areas, which may initiate surface pitting. The mechanisms of chromate inhibition in these localized corrosion processes were identified. The environmental hazard of chromates was also highlighted, serves as the impetus for chromate coating replacement. Sol-gel coatings are shown as an excellent alternative, based on environment compliance, flexibility in the composition control, and reasonable costs. Several sol-gel coatings were formulated and applied to the surface of an AA2024-T3 alloy. The coating composition and bonding were analyzed with XPS and FTIR, surface morphology was studied with SEM and AFM, and corrosion protection properties were tested with EIS, PDS, salt water immersion, and salt-fog exposure. The results demonstrated that epoxy-zirconate sol-gel coatings can provide excellent barrier properties. A novel SVET technique was applied for studies of local electrochemical processes in the pitting formation. This technique was further refined in model studies of aluminum surfaces with artificially created local cathodic regions, experimental studies of chromate inhibition with pit formation, and pitting development studies in sol-gel coatings with artificially introduced defects. Mechanisms of pitting development and inhibition with the pit initiation and growth kinetics were established. The Zr-epoxy coatings are subjected to the pit development and undercutting in the absence of the corrosion inhibitors. Several organic and non-organic inhibitors were evaluated in the sol-gel coating composition. Organic inhibitors had a better compliance with sol-gel chemistry and were identified for future studies. Experiments were performed to verify that sol

  13. On-line Eclipse Resources from the U.S. Naval Observatory: Planning Ahead for April 2024

    NASA Astrophysics Data System (ADS)

    Fredericks, Amy C.; Bartlett, J. L.; Bell, S.; Stapleton, J. C.

    2014-01-01

    On 8 April 2024, “…night from mid-day…” (Archilochus, 648 BCE) will appear to fortunate observers along a narrow band, approximately 115 mi (185 km) wide, that crosses fifteen states from Texas to Maine. In response to growing interest in the two total solar eclipses that will sweep the continental United States in the next 11 years, the U.S. Naval Observatory has developed an on-line resource center with direct links to 2024-specific services: the 2024 April 8 Total Solar Eclipse page (http://aa.usno.navy.mil/data/docs/Eclipse2024.php). The Solar Eclipse Computer (http://aa.usno.navy.mil/data/docs/SolarEclipses.php) calculates tables of local circumstances for events visible throughout the world. A similar service is available for lunar eclipses, Lunar Eclipse Computer (http://aa.usno.navy.mil/data/docs/LunarEclipse.php). The USNO Eclipse Portal (http://astro.ukho.gov.uk/eclbin/query_usno.cgi) provides diagrams and animations showing the global circumstances for events visible throughout the world and local circumstances for events visible at selected locations. The Web site, which includes both solar and lunar eclipses, is a joint effort with Her Majesty’s Nautical Almanac Office. The Eclipses of the Sun and Moon page (http://aa.usno.navy.mil/data/docs/UpcomingEclipses.php) links to electronic copies of the visibility maps from The Astronomical Almanac. The Eclipse Reference List (http://aa.usno.navy.mil/faq/docs/eclipse_ref.php) is a representative survey of the available literature for those interested in delving into these phenomena, either technically or historically. As exciting as the 2024 total solar eclipse, another spectacular event will precede it; a total solar eclipse will cross a different swath of the continent on August 21, 2017. The U.S. Naval Observatory has a resource center for that event as well (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) . If your plans for 2024 are not yet made, visit the 2024 April 8 Total Solar Eclipse

  14. Effect of Segregation of Secondary Phase Particles and "S" Line on Tensile Fracture Behavior of Friction Stir-Welded 2024Al-T351 Joints

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Xiao, B. L.; Ma, Z. Y.

    2013-09-01

    A 5-mm-thick 2024Al-T351 plate was friction stir welded (FSWed) at welding speeds of 100, 200, and 400 mm min-1 with a constant rotation rate of 800 rpm, and the microstructure and tensile fracture behavior of the joints were investigated in detail. FSW resulted in the redistribution of secondary phase particles along the recrystallized grain boundaries at the nugget zone (NZ), forming linear segregation bands consisting of secondary phase particles. The segregation bands, mainly present in the shoulder-driven zone, were believed to result from periodic material flow, with the average band spacing on the longitudinal and horizontal cross sections equal to the tool advancement per revolution. At a low welding speed of 100 mm min-1, in spite of the highest density of segregation bands, the FSWed 2024Al-T351 joint fractured along the low hardness zone (LHZ) of the heat-affected zone because of large hardness gap between NZ and LHZ. Increasing the welding speed to 200 and 400 mm min-1 reduced both the hardness gap between NZ and LHZ and the density of segregation bands. In this case, the segregation bands played a role, resulting in unusual fracture of the joints along the segregation bands. The "S" line originated from the oxide film on the initial butting surfaces and did not affect the fracture behavior of the FSWed 2024Al-T351 joints.

  15. Review and Study of Physics Driven Pitting Corrosion Modeling in 2024-T3 Aluminum Alloys (Postprint)

    DTIC Science & Technology

    2015-05-01

    AFRL-RX-WP-JA-2015-0218 REVIEW AND STUDY OF PHYSICS DRIVEN PITTING CORROSION MODELING IN 2024-T3 ALUMINUM ALLOYS (POSTPRINT) Lingyu...2014 – 1 April 2015 4. TITLE AND SUBTITLE REVIEW AND STUDY OF PHYSICS DRIVEN PITTING CORROSION MODELING IN 2024-T3 ALUMINUM ALLOYS (POSTPRINT) 5a...18 Review and Study of Physics Driven Pitting Corrosion Modeling in 2024-T3 Aluminum Alloys Lingyu Yu 1*, Kumar V. Jata2 1Mechanical Engineering

  16. Quasi-Static Tensile Stress-Strain Curves. 1, 2024-T3510 Aluminum Alloy

    DTIC Science & Technology

    1976-02-01

    herein were conducted as part of the Core Materials Program of the Solid Mechanics Branch of the Terminal Ballistics Laboratory. The objective of this...describing the results of the Core Materials Program, covers quasi-static terVsile tests of 2024-T3510 aluminum E’lloy. The results include Young’s...11.31 4 580.6 9.94 TABLE II MATERIAL PROPERTIES OF 2024-T3510 ALUMINUM ALLOYa Results of Results of Results of Tensileb Compres ion Sonic Testing

  17. Corrosion of aluminum alloy 2024 by microorganisms isolated from aircraft fuel tanks.

    PubMed

    McNamara, Christopher J; Perry, Thomas D; Leard, Ryan; Bearce, Ktisten; Dante, James; Mitchell, Ralph

    2005-01-01

    Microorganisms frequently contaminate jet fuel and cause corrosion of fuel tank metals. In the past, jet fuel contaminants included a diverse group of bacteria and fungi. The most common contaminant was the fungus Hormoconis resinae. However, the jet fuel community has been altered by changes in the composition of the fuel and is now dominated by bacterial contaminants. The purpose of this research was to determine the composition of the microbial community found in fuel tanks containing jet propellant-8 (JP-8) and to determine the potential of this community to cause corrosion of aluminum alloy 2024 (AA2024). Isolates cultured from fuel tanks containing JP-8 were closely related to the genus Bacillus and the fungi Aureobasidium and Penicillium. Biocidal activity of the fuel system icing inhibitor diethylene glycol monomethyl ether is the most likely cause of the prevalence of endospore forming bacteria. Electrochemical impedance spectroscopy and metallographic analysis of AA2024 exposed to the fuel tank environment indicated that the isolates caused corrosion of AA2024. Despite the limited taxonomic diversity of microorganisms recovered from jet fuel, the community has the potential to corrode fuel tanks.

  18. Microstructure and corrosion resistance of a fluorosilane modified silane-graphene film on 2024 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Dun, Yuchao; Zhao, Xuhui; Tang, Yuming; Dino, Sahib; Zuo, Yu

    2018-04-01

    Heptadecafluorodecyl trimethoxysilane (FAS-17) was incorporated into γ-(2,3-epoxypropoxy) propyltrimethoxysilane/graphene (GPTMS/rGO) by adding pre-hydrolyzed FAS-17 solution in GPTMS solution, and a hybrid silane-graphene film (FG/rGO) was prepared on 2024 aluminum alloy surface. The FG/rGO film showed better thermal shock resistance, good adhesion force and high micro-hardness, compared with GPTMS/rGO film. In neutral 3.5 wt% NaCl solution, the corrosion current density for 2024 AA sample with FG/rGO film was 3.40 × 10-3 μA/cm2, which is about one fifth of that for the sample with GPTMS/rGO film. In acidic and alkaline NaCl solutions, the FG/rGO film also showed obviously better corrosion resistance than GPTMS/rGO film. EIS results confirm that the FG/rGO film showed longer performance than GPTMS/rGO film for 2024 AA in NaCl solution. The hydrophobic FAS-17 increased water contact angle of the film surface from 68° to 113°, and changed the stacking structure of graphene in the film. The higher crosslink degree and less interfaces promoted the barrier property of FG/rGO film against aggressive ions and prolonged the performance time in NaCl solution.

  19. Finite element modelling of aluminum alloy 2024-T3 under transverse impact loading

    NASA Astrophysics Data System (ADS)

    Abdullah, Ahmad Sufian; Kuntjoro, Wahyu; Yamin, A. F. M.

    2017-12-01

    Fiber metal laminate named GLARE is a new aerospace material which has great potential to be widely used in future lightweight aircraft. It consists of aluminum alloy 2024-T3 and glass-fiber reinforced laminate. In order to produce reliable finite element model of impact response or crashworthiness of structure made of GLARE, one can initially model and validate the finite element model of the impact response of its constituents separately. The objective of this study was to develop a reliable finite element model of aluminum alloy 2024-T3 under low velocity transverse impact loading using commercial software ABAQUS. Johnson-Cook plasticity and damage models were used to predict the alloy's material properties and impact behavior. The results of the finite element analysis were compared to the experiment that has similar material and impact conditions. Results showed good correlations in terms of impact forces, deformation and failure progressions which concluded that the finite element model of 2024-T3 aluminum alloy under low velocity transverse impact condition using Johnson-Cook plastic and damage models was reliable.

  20. Effect of additional heat treatment of 2024-T3 on the growth of fatigue crack in air and in vacuum

    NASA Technical Reports Server (NTRS)

    Louwaard, E. P.

    1986-01-01

    In order to determine the influence of ductility on the fatigue crack growth rate of aluminum alloys, fatigue tests were carried out on central notched specimens of 2024-T3 and 2024-T8 sheet material. The 2024-T8 material was obtained by an additional heat treatment applied on 2024-T3 (18 hours at 192 C), which increased the static yield strength from 43.6 to 48.9 kgf/sq mm. A change in the ultimate strength was not observed. Fatigue tests were carried out on both materials in humid air and in high vacuum. According to a new crack propagation model, crack extension is supported to be caused by a slip-related process and debonding triggered by the environment. This model predicts an effect of the ductility on the crack growth rate which should be smaller in vacuum than in humid air; however, this was not confirmed. In humid air the crack-growth rate in 2024-T8 was about 2 times faster than in 2024-T3, while in vacuum the ratio was about 2.5. Crack closure measurements gave no indications that crack closure played a significant role in both materials. Some speculative explanations are briefly discussed.

  1. Experimental study on joining of AA6063 and AISI 1040 steel

    NASA Astrophysics Data System (ADS)

    Hynes, N. Rajesh Jesudoss; Raja, S.

    2018-05-01

    Feasibility of joining of dissimilar metals with different physical, chemical and thermal properties such as AA6063 alloy and AISI 1040 steel is worthwhile study, since it has tremendous applications in all most of all engineering domains. The mechanism of bonding is studied using scanning electron microscopy. Impact strength of AA2024/AISI joints, axial shortening distance, micro hardness distribution and joint strength are determined. Micro hardness profile shows increased hardness value at the joint interface, due to grain refinement.

  2. Practicing for 2023 and 2024: What the AAS Solar Eclipse Task Force Learned from the "Great American Eclipse" of 2017

    NASA Astrophysics Data System (ADS)

    Fienberg, R. T.; Speck, A. K.; Habbal, S. R.

    2017-12-01

    More than three years ahead of the "Great American Eclipse" of August 2017, the American Astronomical Society formed the AAS Solar Eclipse Task Force to function as a think tank, coordinating body, and communication gateway to the vast resources available about the 2017 eclipse and solar eclipses more generally. The task force included professional and amateur astronomers, formal and informal educators, and science journalists; many had experienced total solar eclipses before, and others would experience their first totality in August 2017. The AAS task force secured funding from the AAS Council, the National Science Foundation, and NASA. These resources were used mainly for three purposes: (1) to build a website that contains basic information about solar eclipses, safe viewing practices, and eclipse imaging and video, along with resources for educators and the media and a searchable map of eclipse-related events and activities, with links to other authoritative websites with more detailed information; (2) to solicit, receive, evaluate, and fund proposals for mini-grants to support eclipse-related education and public outreach to underrepresented groups both inside and outside the path of totality; and (3) to organize a series of multidisciplinary workshops across the country to prepare communities for the eclipse and to facilitate collaborations between astronomers, meteorologists, school administrators, and transporation and emergency-management professionals. Most importantly, the AAS Solar Eclipse Task Force focused on developing and disseminating appropriate eclipse safety information. The AAS and NASA jointly developed safety messaging that won the endorsement of the American Academies of Opthalmology and Optometry. In the weeks immediately preceding the eclipse, it became clear that the marketplace was being flooded by counterfeit eclipse glasses and solar viewers, leading to a last minute change in our communication strategy. In this talk, we'll review the

  3. Laser shocking of 2024 and 7075 aluminum alloys

    NASA Technical Reports Server (NTRS)

    Clauer, A. H.; Fairand, B. P.; Slater, J. E.

    1977-01-01

    The effect of laser generated stress waves on the microstructure, hardness, strength and stress corrosion resistance of 2024 and 7075 aluminum alloys was investigated. Pulsed CO2 and neodymium-glass lasers were used to determine the effect of wavelength and pulse duration on pressure generation and material property changes. No changes in material properties were observed with CO2 laser. The strength and hardness of 2024-T351 and the strength of 7075-T73 aluminum alloys were substantially improved by the stress wave environments generated with the neodymium-glass laser. The mechanical properties of 2024-T851 and 7075-T651 were unchanged by the laser treatment. The correlation of the laser shock data with published results of flyer plate experiments demonstrated that a threshold pressure needed to be exceeded before strengthening and hardening could occur. Peak pressures generated by the pulsed laser source were less than 7.0 GPa which was below the threshold pressure required to change the mechanical properties of 2024-T851 and 7075-T651. Corrosion studies indicated that laser shocking increased the resistance to local attack in 2024-T351 and 7075-T651.

  4. Evaluating stress corrosion cracking behaviour of high strength AA7075-T651 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Prabhuraj, P.; Rajakumar, S.; Lakshminarayanan, A. K.; Balasubramanian, V.

    2017-12-01

    The objective of the present study is to determine the threshold stress level of stress corrosion cracking (SCC) in AA7075-T651 aluminium alloy by suitable experimentation. The test was carried out using a circumferential notch specimen in a horizontal-type constant load SCC setup in a 3.5 wt.% NaCl solution. The time to failure by SCC was determined at various loading conditions. The threshold stress of AA7075-T651 alloy was found to be 242 MPa in a 3.5 wt.% NaCl solution. The various regions of the fractured surface specimen such as machined notch, SCC region and final overload fracture area were examined using scanning electron microscopy (SEM) in order to identify the SCC mechanism.

  5. Dynamic Response and Microstructure Evolution of AA2219-T4 and AA2219-T6 Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Olasumboye, A.; Owolabi, G.; Odeshi, A.; Zeytinci, A.; Yilmaz, N.

    2018-02-01

    In this study, the dynamic deformation behavior of AA2219 aluminum alloy was investigated in two different temper conditions: T4 and T6, with a view to determining the effect of heat treatment on the microstructure and flow behavior of the material under high strain rates. Split Hopkinson pressure bar experiment was used in determining the dynamic response of the alloy while a digital image correlation system was employed in visualizing and tracking the surface deformation of the specimens. Optical microscopy and scanning electron microscopy were used to assess the microstructure of the material after following standard metallographic specimen preparation techniques. The results obtained showed heterogeneous deformation of the alloy in the two temper conditions. It was observed that the dynamic mechanical behavior of each sample preparation was dependent on its strength properties due to aging type, which in turn controls the metamorphosis of the strengthening precipitates and the initial microstructure. At the maximum strain rate of 3500 s-1, transformed bands leading to crack nucleation was observed in the AA2219-T4 aluminum alloy while AA2219-T6 had fractured at the same strain rate. The modes of crack formation and growth in the two alloys were found to be similar: nucleation, growth and coalescence of voids. However, shear band bifurcation phenomenon was observed only in the AA2219-T6 alloy.

  6. Dynamic Response and Microstructure Evolution of AA2219-T4 and AA2219-T6 Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Olasumboye, A.; Owolabi, G.; Odeshi, A.; Zeytinci, A.; Yilmaz, N.

    2018-06-01

    In this study, the dynamic deformation behavior of AA2219 aluminum alloy was investigated in two different temper conditions: T4 and T6, with a view to determining the effect of heat treatment on the microstructure and flow behavior of the material under high strain rates. Split Hopkinson pressure bar experiment was used in determining the dynamic response of the alloy while a digital image correlation system was employed in visualizing and tracking the surface deformation of the specimens. Optical microscopy and scanning electron microscopy were used to assess the microstructure of the material after following standard metallographic specimen preparation techniques. The results obtained showed heterogeneous deformation of the alloy in the two temper conditions. It was observed that the dynamic mechanical behavior of each sample preparation was dependent on its strength properties due to aging type, which in turn controls the metamorphosis of the strengthening precipitates and the initial microstructure. At the maximum strain rate of 3500 s-1, transformed bands leading to crack nucleation was observed in the AA2219-T4 aluminum alloy while AA2219-T6 had fractured at the same strain rate. The modes of crack formation and growth in the two alloys were found to be similar: nucleation, growth and coalescence of voids. However, shear band bifurcation phenomenon was observed only in the AA2219-T6 alloy.

  7. Evaluation of dip and spray coating techniques in corrosion inhibition of AA2024 alloy using a silicon/zirconium sol-gel film as coating

    NASA Astrophysics Data System (ADS)

    Garcia, R. B. R.; Silva, F. S.; Kawachi, E. Y.

    2017-02-01

    For corrosion protection of aluminum alloy AA2024 -T3 a silicon/zirconium films were obtained via sol-gel process, prepared from tetraethoxysilane and zirconium acetate, in acid medium with a 5 wt% of nonionic surfactant in order to replace the pre-treatment based on chromium conversion coatings. A homogeneous film was obtained and deposited, at low viscosity condition of the sol (˜10cP), by dip and spray coating techniques. The films morphology was evaluated by Scanning Electron Microscopy (SEM), and to know more about the used deposition methodology, the deposited mass and the film thickness were measured. The corrosion protection efficiency of deposited films was evaluated by potentiodynamic polarization. The film deposition by both dip and spray coatings were effective for the deposition of a homogeneous film layer, and the results showed the thickness is directly related with the deposited mass, and the film deposited by spray technique presented the lower value. Potentiodynamic polarization indicated that the film deposited by spray coating apparently has a better inert ceramic film due the polarization resistance increased around 57% against 27 and 14% of dip coating samples (4 and 1 layer, respectively).

  8. Fracture mechanics data for 2024-T861 and 2124-T851 aluminum

    NASA Technical Reports Server (NTRS)

    Pionke, L. J.; Linback, R. K.

    1974-01-01

    The fracture toughness and fatigue flaw growth characteristics of 2024-T861 and 2124-T851 aluminum were evaluated under plane stress conditions. Center cracked tension specimens were employed to evaluate these properties under a number of different test conditions which included variations in specimen thickness, specimen orientation, test environment, and initial flaw size. The effect of buckling was also investigated for all tests of thin gage specimens, and the effect of frequency and stress ratio was evaluated for the cyclic tests. Fracture toughness test results were analyzed and presented in terms of fracture resistance curves; fatigue flaw growth data was analyzed using empirical rate models. The results of the study indicate that both fracture toughness and resistance to fatigue crack growth improve with increasing temperature and decreasing thickness. The presence of buckling during testing of thin gage panels was found to degrade the resistance to fatigue flaw growth only at elevated temperatures.

  9. Investigation of Microstructure and Microhardness in Self-Reacting Friction Stir Welded AA2014-T6 and AA2219-T87

    NASA Technical Reports Server (NTRS)

    Horton, K. Renee; McGill, Preston; Barkey, Mark

    2011-01-01

    Friction stir welding (FSW) is a solid state welding process with potential advantages for aerospace and automotive industries dealing with light alloys. Self-reacting friction stir welding (SR-FSW) is one variation of the FSW process being developed at the National Aeronautics and Space Administration (NASA) for use in the fabrication of propellant tanks. This work reports on the microstructure and microhardness of SR-FSW between two dissimilar aluminum alloys. Specifically, the study examines the cross section of the weld joint formed between an AA2014-T6 plate on the advancing side and an AA2219-T87 plate on the retreating side. The microstructural analysis shows an irregularly displaced weld seam from the advancing side past the thermo-mechanical affected zone (TMAZ) into the weld nugget region. There are sharp variations in the microhardness across the weld. These variations are described in the paper and mechanisms for their formation are discussed.

  10. Microstructure Evolution during Dissimilar Friction Stir Welding of AA7003-T4 and AA6060-T4.

    PubMed

    Dong, Jialiang; Zhang, Datong; Zhang, Weiwen; Zhang, Wen; Qiu, Cheng

    2018-02-27

    In this work, the dissimilar joint of AA7003-T4 and 6060-T4 alloy has been produced by friction stir welding (FSW). The microstructure was examined by optical microscope (OM), electron back scattered diffraction (EBSD), transmission electron microscopy (TEM), and the mechanical properties of the joint were investigated. It is demonstrated that sound dissimilar joint can be produced through FSW. In the nugget; precipitations dissolve into the matrix and η' reprecipitate subsequently; and the elongated aluminum grains are replaced by fine and equiaxed grains due to dynamic recrystallization (DRX). In the heat affected zone (HAZ), coarse β' and η precipitates are formed and the aluminum grains are coarser as compared to the base materials. In the thermo-mechanical affected zone (TMAZ), equiaxed and elongated grains coexist due to incomplete DRX. The ultimate tensile strength of the dissimilar joint is 159.2 MPa and its elongation is 10.4%. The weak area exists in the HAZ of 6060 alloy, which is placed in the retreating side during FSW. The correlations between the microstucture and mechanical properties of the dissimilar joint are discussed.

  11. The influence of surface friction on the AA2024 microstructure

    NASA Astrophysics Data System (ADS)

    Eliseev, A. A.; Kolubaev, E. A.; Fortuna, S. V.

    2017-12-01

    This work is devoted to the study of the effect of sliding at velocities close to those achieved during friction stir welding or friction drilling on the microstructural evolution of 2024 aluminum alloy. The distribution of both solid solution grains and intermetallic precipitates is analyzed. No layers of recrystallized grains depleted by precipitates, which is a common finding in FSW or friction drilling, are found below the worn surface independently of the sliding velocity. A small precipitate content and size changes alone are observed.

  12. Microstructure Evolution during Dissimilar Friction Stir Welding of AA7003-T4 and AA6060-T4

    PubMed Central

    Dong, Jialiang; Zhang, Datong; Zhang, Weiwen; Zhang, Wen; Qiu, Cheng

    2018-01-01

    In this work, the dissimilar joint of AA7003-T4 and 6060-T4 alloy has been produced by friction stir welding (FSW). The microstructure was examined by optical microscope (OM), electron back scattered diffraction (EBSD), transmission electron microscopy (TEM), and the mechanical properties of the joint were investigated. It is demonstrated that sound dissimilar joint can be produced through FSW. In the nugget; precipitations dissolve into the matrix and η′ reprecipitate subsequently; and the elongated aluminum grains are replaced by fine and equiaxed grains due to dynamic recrystallization (DRX). In the heat affected zone (HAZ), coarse β′ and η precipitates are formed and the aluminum grains are coarser as compared to the base materials. In the thermo-mechanical affected zone (TMAZ), equiaxed and elongated grains coexist due to incomplete DRX. The ultimate tensile strength of the dissimilar joint is 159.2 MPa and its elongation is 10.4%. The weak area exists in the HAZ of 6060 alloy, which is placed in the retreating side during FSW. The correlations between the microstucture and mechanical properties of the dissimilar joint are discussed. PMID:29495463

  13. Experimental Investigation on Friction Stir Welding of Cryorolled AA2219 Aluminum Alloy Joints

    NASA Astrophysics Data System (ADS)

    Babu, K. Kamal; Panneerselvam, K.; Sathiya, P.; Haq, A. Noorul; Sundarrajan, S.; Mastanaiah, P.; Murthy, C. V. Srinivasa

    2017-07-01

    In this paper, experimental investigation on cryorolled aluminum AA2219-T87 plate by using friction stir welding (FSW) process is carried out. AA2219-T87 plates with a size of 200×100×22.4 mm were rolled and reduced to 12.2mm thickness (more than 45% of reduction in total thickness of the base material) at cryogenic temperature (operating temperature range -90--30∘C). The cryorolled (CR) plates have reduced grain size, improved hardness and increased corrosion resistance property compared with the uncryorolled AA2219-T87 plates. FSW joints of cryorolled AA2219-T87 plates were prepared using cylindrical threaded FSW tool pin profile. Mechanical and metallurgical behaviors of friction stir welded joints were analyzed and the effects of the FSW process parameters are discussed in this paper. The variation of microhardness in the FSW joint regions were correlated with the microstructure of FSW joints. Cryorolled plate and FSW joints were tested for corrosion resistance using potentiodynamic polarization test. FSW joints shows better result during the corrosion resistance analysis compared to base AA2219-T87. The X-ray diffraction (XRD) test results showed that fine α-Al grains with eutectic phase (Al2Cu) were present in the weld nugget (WN). The large clusters of strengthening precipitates were reduced in size and merged with the weld nugget portion.

  14. Auger electron spectroscopy and Rutherford backscattering studies of copper in 2024-T3 aluminum following electrochemical anodization in phosphoric acid

    NASA Astrophysics Data System (ADS)

    Solomon, J. S.

    1981-05-01

    The effects of the electrochemical anodization of dioxidized 2024-T3 aluminum on copper were characterized by Auger electron spectroscopy and Rutherford backscattering. Anodization was performed in phosphoric acid at constant potential. Data is presented which shows that constant potential anodization of 2024-T3 is more efficient than aluminum in terms of oxide growth rates for short anodization times. However the maximum anodic oxide thickness achievable on the alloy is less than the pure metal. Copper is shown to be enriched at the oxide metal interface because of its diffusion from the bulk during anodization. The presence of copper at the oxide-metal interface is shown to affect oxide morphology.

  15. Fatigue crack growth in 2024-T3 aluminum under tensile and transverse shear stresses

    NASA Technical Reports Server (NTRS)

    Viz, Mark J.; Zehnder, Alan T.

    1994-01-01

    The influence of transverse shear stresses on the fatigue crack growth rate in thin 2024-T3 aluminum alloy sheets is investigated experimentally. The tests are performed on double-edge cracked sheets in cyclic tensile and torsional loading. This loading generates crack tip stress intensity factors in the same ratio as the values computed for a crack lying along a lap joint in a pressurized aircraft fuselage. The relevant fracture mechanics of cracks in thin plates along with the details of the geometrically nonlinear finite element analyses used for the test specimen calibration are developed and discussed. Preliminary fatigue crack growth data correlated using the fully coupled stress intensity factor calibration are presented and compared with fatigue crack growth data from pure delta K(sub I)fatigue tests.

  16. Experimental and Numerical Study of Needle Peening Effects in Aluminium Alloy 2024-T3 Sheets

    NASA Astrophysics Data System (ADS)

    Mendez Romero, Julio Alberto

    Peening of metallic components is an effective treatment used in aerospace and automotive applications to improve fatigue properties or to blend and repair localized damage. This process is typically carried out using metallic airborne media, called shot. However, different processes make use of different media, such is the case of hard, pneumatically powered needles of needle peening equipment. In order to obtain a better understanding of the effects of needle peening in the same context as shot peening, this research work had as an objective to study in detail the behavior of the needle peening equipment in order to characterize the process, design an experimental campaign to measure the effects of needle peening on AA2024-T3 and to develop and validate a Finite Element (FE) model capable of replicating the results of needle peening. The needle peening equipment prototype, called SPIKERRTM, was developed by Shockform Aeronautique Inc. The equipment was characterized by utilizing high-speed camera recording in order to study its behaviour by varying the operating pressure. The obtained collection of images was ran through a newly developed digital image algorithm, so as to quantify the needles' velocity and frequency. The impact velocity and impact frequency were determined for different equipment operating parameters. It was concluded that both the average impact velocity and the impact frequency increase as the pressure becomes larger. Behaviour anomalies among the different needles, such as frequency and velocity variations, were brought to light; these conclusions could be of interest to the manufacturer. Ideally, all of the needles should behave as similarly as possible so as to produce a more uniform process. The response to needle peening of AA2024-T3 in 1.6 mm thick sheet form was studied by needle peening test specimens with dimensions of an Almen strips using the SPIKERRTM. AA2024-T3 was selected since it was extensively studied at Ecole Polytechnique de

  17. Evolution of Microstructure and Stress Corrosion Cracking Behavior of AA2219 Plate to Ring Weld Joints in 3.5 Wt Pct NaCl Solution

    NASA Astrophysics Data System (ADS)

    Venugopal, A.; Narayanan, P. Ramesh; Sharma, S. C.

    2016-04-01

    AA2219 aluminum alloy plate (T87) and ring (T851) were joined by tungsten inert gas (TIG) welding using multi-pass welding. The mechanical properties and stress corrosion cracking (SCC) resistance of the above base metals (BMs) in different directions (L, LT, and ST) were examined. Similarly, the weld metal joined by plate to plate and plate to ring (PR) joints was evaluated. The results revealed that the mechanical properties of the ring were comparatively lower than the plate. This was found to be due to the extremely coarse grain size of the ring along with severe Cu-rich segregation along the grain boundaries when compared to the plate material. The SCC resistance of the base and weldments were found to be good and not susceptible to SCC. This was shown to be due to high values of SCC index (>0.9) and the typical ductile cracking morphology of the BM and the weld joints after SCC test in the environment (3.5 wt pct NaCl) when compared to test performed in the control environment (air). However, the corrosion resistance of the weld interface between the FZ and ring was inferior to the FZ-plate interface.

  18. Stress Ratio Effects on Crack Opening Loads and Crack Growth Rates in Aluminum Alloy 2024

    NASA Technical Reports Server (NTRS)

    Riddell, William T.; Piascik, Robert S.

    1998-01-01

    The effects of stress ratio (R) and crack opening behavior on fatigue crack growth rates (da/dN) for aluminum alloy (AA) 2024-T3 were investigated using constant-delta K testing, closure measurements, and fractography. Fatigue crack growth rates were obtained for a range of delta K and stress ratios. Results show that constant delta K fatigue crack growth for R ranging from near 0 to 1 is divided into three regions. In Region 1, at low R, da/dN increases with increasing R. In Region 2, at intermediate R, fatigue crack growth rates are relatively independent of R. In Region 3, at high R, further increases in da/dN are observed with increasing R.

  19. Corrosion inhibition by inorganic cationic inhibitors on the high strength alumunium alloy, 2024-T3

    NASA Astrophysics Data System (ADS)

    Chilukuri, Anusha

    The toxicity and carcinogenic nature of chromates has led to the investigation of environmentally friendly compounds that offer good corrosion resistance to AA 2024-T3. Among the candidate inhibitors are rare earth metal cationic (REM) and zinc compounds, which have received much of attention over the past two decades. A comparative study on the corrosion inhibition caused by rare earth metal cations, Ce3+, Pr3+, La3+ and Zn2+ cations on the alloy was done. Cathodic polarization showed that these inhibitor ions suppress the oxygen reduction reaction (ORR) to varying extents with Zn2+ providing the best inhibition. Pr3+ exhibited windows of concentration (100-300 ppm) in which the corrosion rate is minimum; similar to the Ce3+ cation. Scanning Electron Microscopy (SEM) studies showed that the mechanism of inhibition of the Pr3+ ion is also similar to that of the Ce3+ ion. Potentiodynamic polarization experiments after 30 min immersion time showed greatest suppression of oxygen reduction reaction in neutral chloride solutions (pH 7), which reached a maximum at a Zn2+ ion concentration of 5 mM. Anodic polarization experiments after 30 min immersion time, showed no anodic inhibition by the inhibitor in any concentration (0.1 mM - 10 mM) and at any pH. However, anodic polarization of samples immersed after longer immersion times (upto 4 days) in mildly acidic Zn2+ (pH 4) solutions showed significant reduction in anodic kinetics indicating that zinc also acts as a “slow anodic inhibitor”. In contrast to the polarization experiments, coupons exposed to inhibited acidic solutions at pH 4 showed complete suppression of dissolution of Al2CuMg particles compared to zinc-free solutions in the SEM studies. Samples exposed in pH 4 Zn2+-bearing solution exhibited highest polarization resistance which was also observed to increase with time. In deaerated solutions, the inhibition by Zn2+ at pH 4 is not observed as strongly. The ability to make the interfacial electrolyte

  20. Four-point-bend fatigue of AA 2026 aluminum alloys

    NASA Astrophysics Data System (ADS)

    Li, J. X.; Zhai, T.; Garratt, M. D.; Bray, G. H.

    2005-09-01

    High-cycle fatigue tests were carried out on a newly developed high-strength AA 2026 Al alloy, which was in the form of extrusion bars with square and rectangular cross sections, using a self-aligning four-point-bend rig at room temperature, 15 Hz, and R = 0.1, in lab air. The fatigue strength of the square and rectangular bars was measured to be 85 and 90 pct of their yield strength, respectively, more than twice that of the predecessor to the 2026 alloy (the AA 2024 Al alloy). Fatigue cracks were found to be always initiated at large Θ' (Al7Cu2(Fe,Mn)) particles and to propagate predominantly in a crystallographic mode in the AA 2026 alloy. The fatigue fractographies of the square and rectangular extrusion bars were found to be markedly different, due to their different grain structures (fibril and layered, respectively). Fracture steps on the crack face were found in both of these extrusion bars. Since the 2026 alloy was purer in terms of Fe and Si content, it contained much less coarse particles than in a 2024 alloy. This partially accounted for the superior fatigue strength of the 2026 alloy.

  1. Influences of post weld heat treatment on tensile strength and microstructure characteristics of friction stir welded butt joints of AA2014-T6 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Rajendran, C.; Srinivasan, K.; Balasubramanian, V.; Balaji, H.; Selvaraj, P.

    2016-08-01

    Friction stir welded (FSWed) joints of aluminum alloys exhibited a hardness drop in both the advancing side (AS) and retreating side (RS) of the thermo-mechanically affected zone (TMAZ) due to the thermal cycle involved in the FSW process. In this investigation, an attempt has been made to overcome this problem by post weld heat treatment (PWHT) methods. FSW butt (FSWB) joints of Al-Cu (AA2014-T6) alloy were PWHT by two methods such as simple artificial aging (AA) and solution treatment followed by artificial aging (STA). Of these two treatments, STA was found to be more beneficial than the simple aging treatment to improve the tensile properties of the FSW joints of AA2014 aluminum alloy.

  2. Coarsening of AA6013-T6 Precipitates During Sheet Warm Forming Applications

    NASA Astrophysics Data System (ADS)

    Di Ciano, M.; DiCecco, S.; Esmaeili, S.; Wells, M. A.; Worswick, M. J.

    2018-03-01

    The use of warm forming for AA6xxx-T6 sheet is of interest to improve its formability; however, the effect warm forming may have on the coarsening of precipitates and the mechanical strength of these sheets has not been well studied. In this research, the coarsening behavior of AA6013-T6 precipitates has been explored, in the temperature range of 200-300 °C, and time of 30 s up to 50 h. Additionally, the effect of warm deformation on coarsening behavior was explored using: (1) simulated warm forming tests in a Gleeble thermo-mechanical simulator and (2) bi-axial warm deformation tests. Using a strong obstacle model to describe the yield strength (YS) evolution of the AA6013-T6 material, and a Lifshitz, Slyozov, and Wagner (LSW) particle coarsening law to describe the change in precipitate size with time, the coarsening kinetics were modeled for this alloy. The coarsening kinetics in the range of 220-300 °C followed a trend similar to that previously found for AA6111 for the 180-220 °C range. There was strong evidence that coarsening kinetics were not altered due to warm deformation above 220 °C. For warm forming between 200 and 220 °C, the YS of the AA6013-T6 material increased slightly, which could be attributed to strain hardening during warm deformation. Finally, a non-isothermal coarsening model was used to assess the potential reduction in the YS of AA6013-T6 for practical processing conditions related to auto-body manufacturing. The model calculations showed that 90% of the original AA6013-T6 YS could be maintained, for warm forming temperatures up to 280 °C, if the heating schedule used to get the part to the warm forming temperature was limited to 1 min.

  3. Multi-Objective Optimization of Friction Stir Welding Process Parameters of AA6061-T6 and AA7075-T6 Using a Biogeography Based Optimization Algorithm

    PubMed Central

    Tamjidy, Mehran; Baharudin, B. T. Hang Tuah; Paslar, Shahla; Matori, Khamirul Amin; Sulaiman, Shamsuddin; Fadaeifard, Firouz

    2017-01-01

    The development of Friction Stir Welding (FSW) has provided an alternative approach for producing high-quality welds, in a fast and reliable manner. This study focuses on the mechanical properties of the dissimilar friction stir welding of AA6061-T6 and AA7075-T6 aluminum alloys. The FSW process parameters such as tool rotational speed, tool traverse speed, tilt angle, and tool offset influence the mechanical properties of the friction stir welded joints significantly. A mathematical regression model is developed to determine the empirical relationship between the FSW process parameters and mechanical properties, and the results are validated. In order to obtain the optimal values of process parameters that simultaneously optimize the ultimate tensile strength, elongation, and minimum hardness in the heat affected zone (HAZ), a metaheuristic, multi objective algorithm based on biogeography based optimization is proposed. The Pareto optimal frontiers for triple and dual objective functions are obtained and the best optimal solution is selected through using two different decision making techniques, technique for order of preference by similarity to ideal solution (TOPSIS) and Shannon’s entropy. PMID:28772893

  4. Multi-Objective Optimization of Friction Stir Welding Process Parameters of AA6061-T6 and AA7075-T6 Using a Biogeography Based Optimization Algorithm.

    PubMed

    Tamjidy, Mehran; Baharudin, B T Hang Tuah; Paslar, Shahla; Matori, Khamirul Amin; Sulaiman, Shamsuddin; Fadaeifard, Firouz

    2017-05-15

    The development of Friction Stir Welding (FSW) has provided an alternative approach for producing high-quality welds, in a fast and reliable manner. This study focuses on the mechanical properties of the dissimilar friction stir welding of AA6061-T6 and AA7075-T6 aluminum alloys. The FSW process parameters such as tool rotational speed, tool traverse speed, tilt angle, and tool offset influence the mechanical properties of the friction stir welded joints significantly. A mathematical regression model is developed to determine the empirical relationship between the FSW process parameters and mechanical properties, and the results are validated. In order to obtain the optimal values of process parameters that simultaneously optimize the ultimate tensile strength, elongation, and minimum hardness in the heat affected zone (HAZ), a metaheuristic, multi objective algorithm based on biogeography based optimization is proposed. The Pareto optimal frontiers for triple and dual objective functions are obtained and the best optimal solution is selected through using two different decision making techniques, technique for order of preference by similarity to ideal solution (TOPSIS) and Shannon's entropy.

  5. 46 CFR 35.20-35 - Whistling-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Whistling-T/ALL. 35.20-35 Section 35.20-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-35 Whistling—T/ALL. The unnecessary sounding of a vessel's whistle is prohibited within any harbor limits of the...

  6. 46 CFR 35.20-35 - Whistling-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Whistling-T/ALL. 35.20-35 Section 35.20-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-35 Whistling—T/ALL. The unnecessary sounding of a vessel's whistle is prohibited within any harbor limits of the...

  7. 48 CFR 2024.202 - Policy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Policy. 2024.202 Section 2024.202 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION SOCIOECONOMIC PROGRAMS PROTECTION OF PRIVACY AND FREEDOM OF INFORMATION Freedom of Information Act 2024.202 Policy. The provisions...

  8. 48 CFR 2024.202 - Policy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Policy. 2024.202 Section 2024.202 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION SOCIOECONOMIC PROGRAMS PROTECTION OF PRIVACY AND FREEDOM OF INFORMATION Freedom of Information Act 2024.202 Policy. The provisions...

  9. 48 CFR 2024.202 - Policy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Policy. 2024.202 Section 2024.202 Federal Acquisition Regulations System NUCLEAR REGULATORY COMMISSION SOCIOECONOMIC PROGRAMS PROTECTION OF PRIVACY AND FREEDOM OF INFORMATION Freedom of Information Act 2024.202 Policy. The provisions...

  10. Microstructure and Residual Stress Distributions Under the Influence of Welding Speed in Friction Stir Welded 2024 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Moghadam, Danial Ghahremani; Farhangdoost, Khalil; Nejad, Reza Masoudi

    2016-06-01

    Friction stir welding was conducted on 8-mm-thick plates made of AA2024-T351 aluminum alloy at tool traverse speeds between 8 and 31.5 mm/minutes and tool rotational speed between 400 and 800 rpm. Metallographic analyses and mechanical tests including hardness, tensile, residual stress, and fracture toughness tests were carried out to evaluate the microstructural and mechanical properties of the joints as a function of the process parameters. The finite element simulation of the FSW process was also performed using a thermal model. The hardness test results show that the increase in rotational speed or decrease in traverse speed of the tool would cause a decrease in weld zone hardness. The best tensile properties are obtained at rotational/traverse speed ratio between 20 and 32. Also, the longitudinal residual stress profiles were evaluated by employing X-ray diffraction method. The numerical and experimental results showed that the increase in a traverse or rotational speed would increase the residual stress of the weld zone. From the fracture toughness results, it was found that the welding process decreases the joints fracture toughness 18 to 49 pct with respect to the base metal.

  11. 20 CFR 202.4 - Control.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Control. 202.4 Section 202.4 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT EMPLOYERS UNDER THE ACT § 202.4 Control. A company or person is controlled by one or more carriers, whenever there exists in one...

  12. 20 CFR 202.4 - Control.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Control. 202.4 Section 202.4 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT EMPLOYERS UNDER THE ACT § 202.4 Control. A company or person is controlled by one or more carriers, whenever there exists in one...

  13. 20 CFR 202.4 - Control.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Control. 202.4 Section 202.4 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT EMPLOYERS UNDER THE ACT § 202.4 Control. A company or person is controlled by one or more carriers, whenever there exists in one...

  14. 20 CFR 202.4 - Control.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Control. 202.4 Section 202.4 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT EMPLOYERS UNDER THE ACT § 202.4 Control. A company or person is controlled by one or more carriers, whenever there exists in one...

  15. 20 CFR 202.4 - Control.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Control. 202.4 Section 202.4 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT EMPLOYERS UNDER THE ACT § 202.4 Control. A company or person is controlled by one or more carriers, whenever there exists in one...

  16. Transient thermal analysis during friction stir welding between AA2014-T6 and pure copper

    NASA Astrophysics Data System (ADS)

    Gadhavi, A. R.; Ghetiya, N. D.; Patel, K. M.

    2018-04-01

    AA2xxx-Cu alloys showed larger applications in the defence sectors and in aerospace industries due to high strength to weight ratio and toughness. FSW in a butt joint configuration was carried out between AA2014-T6 and pure Copper placing AA2014 on AS and Cu on RS. Temperature profiles were observed by inserting K-type thermocouples in the mid-thickness at various locations of the plate. A sharp decrease in temperature profiles was observed on Copper side due to its higher thermal conductivity. A thermal numerical model was prepared in ANSYS to compare the simulated temperature profiles with the experimental temperature profiles and both the temperature profiles were found to be in good agreement.

  17. Reinforcement with alumina particles at the interface region of AA6101-T6 and AA1350 alloys during friction stir welding

    NASA Astrophysics Data System (ADS)

    Ashok Kumar, R.; Thansekhar, M. R.

    2018-04-01

    This paper deals the combinational effect of friction stir welding and friction stir processing on dissimilar AA6101-T6 and AA1350 aluminium alloys. For that, alumina particles are reinforced at interface region of AA6101-T6 and AA1350 aluminium alloys. Friction Stir Welding and Friction Stir Processing are done simultaneously for various sizes of groove. To analyze the welding quality and surface modifications, mechanical, wear and microstructural tests are carried out. Among these, smallest groove of 0.5 mm width and 1 mm depth reveals highest tensile and bending strengths and largest groove of 2 mm width and 3 mm depth gives maximum hardness and wear resistance. Taguchi technique shows that groove width is most influencing parameter. Developed second order models with interaction predict the responses with minimum error.

  18. Chromium-free conversion coatings based on inorganic salts (Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applications

    NASA Astrophysics Data System (ADS)

    Santa Coloma, P.; Izagirre, U.; Belaustegi, Y.; Jorcin, J. B.; Cano, F. J.; Lapeña, N.

    2015-08-01

    Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot scale to improve the corrosion resistance of the AA2024-T3 and AA7075-T6 aluminum alloys for aircraft applications. The influence of the presence of Zr and Ti in the Zr/Ti/Mn/Mo conversion bath's formulation on the corrosion resistance of the coated alloys was investigated. The corrosion resistance provided by the conversion coatings was evaluated by salt spray exposure and potentiodynamic sweeps. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and atomic force microscopy (AFM) operating in the Kelvin Probe mode (SKPFM) were used to provide microstructural information of the coated samples that achieved the best results in the corrosion tests. The salt spray test evidenced the higher corrosion resistance of the coated samples compared to the bare surfaces for both alloys. The potentiodynamic tests showed that the corrosion current density decreased for coated AA7075-T6 and AA2024-T3 alloys, which indicated an obvious improvement of the corrosion resistance with all the processes for both alloys. Although the corrosion resistance of the coated samples appeared to be higher for the alloy AA7075-T6 than for the alloy AA2024-T3, both alloys achieved the best corrosion protection with the coatings deposited from conversion bath formulations containing no titanium salts. The microscopy analysis on the coated AA7075-T6 samples revealed that a local deposition of Zr compounds and, possibly, an oxidation process occurred in the vicinity of the alloy's intermetallic particles. The amount of the Zr deposits at these locations increased with coating's formulations without Ti, which provided the best corrosion resistance. The Cr-free conversion coatings developed in this study for the AA7075-T6 and AA2024-T3 alloys do not meet yet the strict requirements of the aircraft industry. However, they significantly improved the corrosion

  19. 19 CFR 202.4 - Public hearing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Public hearing. 202.4 Section 202.4 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF COSTS OF PRODUCTION § 202.4 Public hearing. A public hearing will be held in connection with each full investigation...

  20. 19 CFR 202.4 - Public hearing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 3 2012-04-01 2012-04-01 false Public hearing. 202.4 Section 202.4 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF COSTS OF PRODUCTION § 202.4 Public hearing. A public hearing will be held in connection with each full investigation...

  1. 19 CFR 202.4 - Public hearing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 3 2014-04-01 2014-04-01 false Public hearing. 202.4 Section 202.4 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF COSTS OF PRODUCTION § 202.4 Public hearing. A public hearing will be held in connection with each full investigation...

  2. 19 CFR 202.4 - Public hearing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 3 2013-04-01 2013-04-01 false Public hearing. 202.4 Section 202.4 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF COSTS OF PRODUCTION § 202.4 Public hearing. A public hearing will be held in connection with each full investigation...

  3. 19 CFR 202.4 - Public hearing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 3 2011-04-01 2011-04-01 false Public hearing. 202.4 Section 202.4 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF COSTS OF PRODUCTION § 202.4 Public hearing. A public hearing will be held in connection with each full investigation...

  4. 19 CFR 10.2024 - Indirect materials.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Indirect materials. 10.2024 Section 10.2024... Agreement Rules of Origin § 10.2024 Indirect materials. An indirect material, as defined in § 10.2013(i), will be considered to be an originating material without regard to where it is produced. Example...

  5. Proof test and fatigue crack growth modeling on 2024-T3 aluminum alloy

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.; Poe, C. C., Jr.; Dawicke, D. S.

    1990-01-01

    Pressure proof testing of aircraft fuselage structures has been suggested as a means of screening critical crack sizes and of extending their useful life. The objective of this paper is to study the proof-test concept and to model the crack-growth process on a ductile material. Simulated proof and operational fatigue life tests have been conducted on cracked panels made of 2024-T3 aluminum alloy sheet material. A fatigue crack-closure model was modified to simulate the proof test and operational fatigue cycling. Using crack-growth rate and resistance-curve data, the model was able to predict crack growth during and after the proof load. These tests and analyses indicate that the proof test increases fatigue life; but the beneficial life, after a 1.33 or 1.5 proof, was less than a few hundred cycles.

  6. Built-up edge investigation in vibration drilling of Al2024-T6.

    PubMed

    Barani, A; Amini, S; Paktinat, H; Fadaei Tehrani, A

    2014-07-01

    Adding ultrasonic vibrations to drilling process results in an advanced hybrid machining process, entitled "vibration drilling". This study presents the design and fabrication of a vibration drilling tool by which both rotary and vibrating motions are applied to drill simultaneously. High frequency and low amplitude vibrations were generated by an ultrasonic transducer with frequency of 19.65 kHz. Ultrasonic transducer was controlled by a MPI ultrasonic generator with 3 kW power. The drilling tool and workpiece material were HSS two-flute twist drill and Al2024-T6, respectively. The aim of this study was investigating on the effect of ultrasonic vibrations on built-up edge, surface quality, chip morphology and wear mechanisms of drill edges. Therefore, these factors were studied in both vibration and ordinary drilling. Based on the achieved results, vibration drilling offers less built-up edge and better surface quality compared to ordinary drilling. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Influence of Crack-Tip Configurations on the Fracture Response of 0.04-Inch Thick 2024-T3 Aluminum Alloy Sheet

    NASA Technical Reports Server (NTRS)

    Johnston, William M.; Newman, James C. (Technical Monitor)

    2002-01-01

    A series of fracture tests were conducted on Middle-crack tension M(T) and compact tension C(T) specimens to determine the effects of specimen type, specimen width, notch tip sharpness and buckling on the fracture behavior of cracked thin sheet (0.04 inch thick) 2024-T3 aluminum alloy material. A series of M(T) specimens were tested with three notch tip configurations: (1) a fatigue pre-cracked notch, (2) a 0.010-inch-diameter wire electrical discharge machined (EDM) notch, and (3) a EDM notch sharpened with a razor blade. The test procedures are discussed and the experimental results for failure stress, load vs. crack extension and the material stress-strain response are reported.

  8. F-35 Joint Strike Fighter Aircraft (F-35)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report ( SAR ) RCS: DD-A&T(Q&A)823-198 F-35 Joint Strike Fighter Aircraft (F-35) As of FY 2017 President’s Budget Defense...Acquisition Management Information Retrieval (DAMIR) March 21, 2016 08:47:09 UNCLASSIFIED F-35 December 2015 SAR March 21, 2016 08:47:09 UNCLASSIFIED 2...Document OSD - Office of the Secretary of Defense O&S - Operating and Support PAUC - Program Acquisition Unit Cost F-35 December 2015 SAR March 21

  9. Periodic Overload and Transport Spectrum Fatigue Crack Growth Tests of Ti62222STA and Al2024T3 Sheet

    NASA Technical Reports Server (NTRS)

    Phillips, Edward P.

    1999-01-01

    Variable amplitude loading crack growth tests have been conducted to provide data that can be used to evaluate crack growth prediction codes. Tests with periodic overloads or overloads followed by underloads were conducted on titanium alloy Ti-6Al-2Sn-2Zr-2Mo-2Cr solution treated and aged (Ti62222STA) material at room temperature and at 350 F. Spectrum fatigue crack growth tests were conducted on two materials (Ti62222STA and aluminum alloy 2024-T3) using two transport lower-wing test spectra at two temperatures (room temperature and 350 F (Ti only)). Test lives (growth from an initial crack half-length of 0.15 in. to failure) were recorded in all tests and the crack length against cycles (or flights) data were recorded in many of the tests. The following observations were made regarding the test results: (1) in tests of the Ti62222STA material, the tests at 350 F had longer lives than those at room temperature, (2) in tests to the MiniTwist spectrum, the Al2024T3 material showed much greater crack growth retardations due to the highest stresses in the spectrum than did the Ti62222STA material, and (3) comparisons of material crack growth performances on an "equal weight" basis were spectrum dependent.

  10. The Microjet of AA Tau

    NASA Astrophysics Data System (ADS)

    Cox, A. W.; Hilton, G. M.; Williger, G. M.; Grady, C. A.; Woodgate, B.

    2005-12-01

    The microjet of AA Tau A.W. Cox (Atholton High School, Columbia MD), G.M. Hilton (SSAI and GSFC), G.M. Williger (JHU and U. Louisville), C.A. Grady (Eureka Scientific and GSFC) B.Woodgate (NASA's GSFC) AA Tau is a classical T Tauri star with a spatially resolved disk viewed at approximately 70 degrees from pole-on. Photo-polarimetric variability of the star has been interpreted as being caused by the stellar magnetic field being inclined at 30 degrees with respect to the stellar rotation axis, producing a warp in the inner disk. Under these conditions, any jet should be less collimated than typical of T Tauri microjets, and should show signs of the jet axis precessing around the stellar rotation axis. When compared with the microjets imaged in the HST/STIS coronagraphic imaging survey, the AA Tau jet has an opening half-angle of approximately 10-15 degrees rather than the 3-5 degrees typical of the other T Tauri stars which have been coronagraphically imaged by HST/STIS. Using the HST data with ultra-narrowband imagery and long slit spectroscopy obtained with the Goddard Fabry-Perot and the Dual Imaging Spectrograph at the Apache Point Observatory 3.5m telescope, we derive the jet inclination, knot ejection epochs, and ejection frequency. We also compare the jet opening angle with model predictions. Apache Point Observatory observations with the Goddard Fabry-Perot were made through a grant of Director's Discretionary Time. Apache Point Observatory is operated by the Astrophysical Research Consortium. The GFP was supported under NASA RTOP 51-188-01-22 to GSFC. Grady is supported under NASA contract NNH05CD30C to Eureka Scientific.

  11. 42 CFR 423.2024 - Objections to the issues.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Objections to the issues. 423.2024 Section 423.2024 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES..., and Judicial Review § 423.2024 Objections to the issues. (a) If an enrollee objects to the issues...

  12. Active corrosion protection of AA2024 by sol-gel coatings with corrosion inhibitors =

    NASA Astrophysics Data System (ADS)

    Yasakau, Kiryl

    A industria aeronautica utiliza ligas de aluminio de alta resistencia para o fabrico dos elementos estruturais dos avioes. As ligas usadas possuem excelentes propriedades mecanicas mas apresentam simultaneamente uma grande tendencia para a corrosao. Por esta razao essas ligas necessitam de proteccao anticorrosiva eficaz para poderem ser utilizadas com seguranca. Ate a data, os sistemas anticorrosivos mais eficazes para ligas de aluminio contem cromio hexavalente na sua composicao, sejam pre-tratamentos, camadas de conversao ou pigmentos anticorrosivos. O reconhecimento dos efeitos carcinogenicos do cromio hexavalente levou ao aparecimento de legislacao banindo o uso desta forma de cromio pela industria. Esta decisao trouxe a necessidade de encontrar alternativas ambientalmente inocuas mas igualmente eficazes. O principal objectivo do presente trabalho e o desenvolvimento de pretratamentos anticorrosivos activos para a liga de aluminio 2024, baseados em revestimentos hibridos produzidos pelo metodo sol-gel. Estes revestimentos deverao possuir boa aderencia ao substrato metalico, boas propriedades barreira e capacidade anticorrosiva activa. A proteccao activa pode ser alcancada atraves da incorporacao de inibidores anticorrosivos no pretratamento. O objectivo foi atingido atraves de uma sucessao de etapas. Primeiro investigou-se em detalhe a corrosao localizada (por picada) da liga de aluminio 2024. Os resultados obtidos permitiram uma melhor compreensao da susceptibilidade desta liga a processos de corrosao localizada. Estudaram-se tambem varios possiveis inibidores de corrosao usando tecnicas electroquimicas e microestruturais. Numa segunda etapa desenvolveram-se revestimentos anticorrosivos hibridos organico-inorganico baseados no metodo sol-gel. Compostos derivados de titania e zirconia foram combinados com siloxanos organofuncionais a fim de obter-se boa aderencia entre o revestimento e o substrato metalico assim como boas propriedades barreira. Testes

  13. Overload and Underload Effects on the Fatigue Crack Growth Behavior of the 2024-T3 Aluminum Alloy

    NASA Technical Reports Server (NTRS)

    Dawicke, David S.

    1997-01-01

    Fatigue crack growth tests were conducted on 0.09 inch thick, 3.0 inch wide middle-crack tension specimens cut from sheets of 2024-T3 aluminum alloy. The tests were conducted using a load sequence that consisted of a single block of 2,500 cycles of constant amplitude loading followed by an overload/underload combination. The largest fatigue crack growth life occurred for the tests with the overload stress equal to 2 times the constant amplitude stress and the underload stress equal to the constant amplitude minimum stress. For the tests with compressive underloads, the fatigue crack growth life decreased with increasing compressive underload stress.

  14. Corrosion behavior of aluminum-alumina composites in aerated 3.5 percent chloride solution

    NASA Astrophysics Data System (ADS)

    Acevedo Hurtado, Paul Omar

    Aluminum based metal matrix composites are finding many applications in engineering. Of these Al-Al2O3 composites appear to have promise in a number of defense applications because of their mechanical properties. However, their corrosion behavior remains suspect, especially in marine environments. While efforts are being made to improve the corrosion resistance of Al-Al2O3 composites, the mechanism of corrosion is not well known. In this study, the corrosion behavior of powder metallurgy processed Al-Cu alloy reinforced with 10, 15, 20 and 25 vol. % Al2O3 particles (XT 1129, XT 2009, XT 2048, XT 2031) was evaluated in aerated 3.5% NaCl solution using microstructural and electrochemical measurements. AA1100-O and AA2024T4 monolithic alloys were also studied for comparison purposes. The composites and unreinforced alloys were subjected to potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) testing. Addition of 25 vol. % Al2O 3 to the base alloys was found to increase its corrosion resistance considerably. Microstructural studies revealed the presence of intermetallic Al2Cu particles in these composites that appeared to play an important role in the observations. Pitting potential for these composites was near corrosion potential values, and repassivation potential was below the corresponding corrosion potential, indicating that these materials begin to corrode spontaneously as soon as they come in contact with the 3.5 % NaCl solution. EIS measurements indicate the occurrence of adsorption/diffusion phenomena at the interface of the composites which ultimately initiate localized or pitting corrosion. Polarization resistance values were extracted from the EIS data for all the materials tested. Electrically equivalent circuits are proposed to describe and substantiate the corrosive processes occurring in these Al-Al2O 3 composite materials.

  15. Effects of Different Filler Metals on the Mechanical Behaviors of GTA Welded AA7A52(T6)

    NASA Astrophysics Data System (ADS)

    Shu, Fengyuan; Lv, Yaohui; Liu, Yuxin; Lin, Jianjun; Sun, Zhe; Xu, Binshi; He, Peng

    2014-06-01

    ER4043, ER5356, and AA7A52 on behalf of the Al-Si, Al-Mg, and Al-Zn-Mg-based welding material, respectively, were chosen as the filler metal to weld AA7A52(T6) plates by GTAW. The variance in mechanical performances of the joints caused by the various filler materials was investigated with reference to the SEM and EDS test results for the weld seam and the fracture surface. Failure was found in the seam for all the welded joints. With regard to the joint obtained with ER4043 welding wire, the total elongation was limited by the brittle intergranular compound Mg2Si of which Mg was introduced by convection mass transfer. As for the other two welds, the content ratio of Zn and Mg was found to play the dominant role in deciding the mechanical properties of the intergranular Mg-Zn compounds which were responsible for the tensile behavior of the joints. The content ratio (wt.%) of beyond 2:1 gave birth to the strengthening phase MgZn2 leading to a ductile fracture. Cr in the seam obtained with AA7A52 filler metal was found to enhance the strength of the joint through isolated particles.

  16. How EF-Tu can contribute to efficient proofreading of aa-tRNA by the ribosome

    PubMed Central

    Noel, Jeffrey K.; Whitford, Paul C.

    2016-01-01

    It has long been recognized that the thermodynamics of mRNA–tRNA base pairing is insufficient to explain the high fidelity and efficiency of aminoacyl-tRNA (aa-tRNA) selection by the ribosome. To rationalize this apparent inconsistency, Hopfield proposed that the ribosome may improve accuracy by utilizing a multi-step kinetic proofreading mechanism. While biochemical, structural and single-molecule studies have provided a detailed characterization of aa-tRNA selection, there is a limited understanding of how the physical–chemical properties of the ribosome enable proofreading. To this end, we probe the role of EF-Tu during aa-tRNA accommodation (the proofreading step) through the use of energy landscape principles, molecular dynamics simulations and kinetic models. We find that the steric composition of EF-Tu can reduce the free-energy barrier associated with the first step of accommodation: elbow accommodation. We interpret this effect within an extended kinetic model of accommodation and show how EF-Tu can contribute to efficient and accurate proofreading. PMID:27796304

  17. Short fatigue crack behavior in notched 2024-T3 aluminum specimens

    NASA Technical Reports Server (NTRS)

    Lee, J. J.; Sharpe, W. N., Jr.

    1986-01-01

    Single-edge, semi-circular notched specimens of Al 2024-T3, 2.3 mm thick, were cyclicly loaded at R-ratios of 0.5, 0.0, -1.0, and -2.0. The notch roots were periodically inspected using a replica technique which duplicates the bore surface. The replicas were examined under an optical microscope to determine the initiation of very short cracks and to monitor the growth of short cracks ranging in length from a few tens of microns to the specimen thickness. In addition to short crack growth measurements, the crack opening displacement (COD) was measured for surface cracks as short as 0.035 mm and for through-thickness cracks using the Interferometric Strain/Displacement Gage (ISDG), a laser-based optical technique. The growth rates of short cracks were faster than the long crack growth rates for R-ratios of -1.0 and -2.0. No significant difference between short and long crack growth rates was observed for R = 0.0. Short cracks had slower growth rates than long cracks for R = 0.5. The crack opening stresses measured for short cracks were smaller than those predicted for large cracks, with little difference appearing for positive R-ratios and large differences noted for negative R-ratios.

  18. 12 CFR 202.4 - General rules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false General rules. 202.4 Section 202.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM EQUAL CREDIT OPPORTUNITY... languages other than English, provided they are available in English upon request. [Reg. B, 68 FR 13161, Mar...

  19. 12 CFR 202.4 - General rules.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 2 2011-01-01 2011-01-01 false General rules. 202.4 Section 202.4 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM EQUAL CREDIT OPPORTUNITY... by §§ 202.5 and 202.13, in a form the applicant may retain. (2) Disclosures in electronic form. The...

  20. Dynamic Multivariate Accelerated Corrosion Test Protocol

    DTIC Science & Technology

    2014-10-01

    atmospheric, accelerated, AA2024-T3, AA6061-T6, AA7075-T3, 1010 steel, AgCl, rare earth conversion coat, magnesium rich primer, polyurethane , Eyring, Monte...morphology and elemental analysis by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and electrochemical determinations of...in the FT-IR analysis; degradation of the components of the high performance polyurethane coatings exposed in the UV/ozone chamber were more

  1. Parametric studies on tensile strength in joining AA6061- T6 and AA7075-T6 by gas metal arc welding process

    NASA Astrophysics Data System (ADS)

    Ishak, M.; Noordin, N. F. M.; Shah, L. H.

    2015-12-01

    Proper selection of the welding parameters can result in better joining. In this study, the effects of various welding parameters on tensile strength in joining dissimilar aluminum alloys AA6061-T6 and AA7075-T6 were investigated. 2 mm thick samples of both base metals were welded by semi-automatic gas metal arc welding (GMAW) using filler wire ER5356. The welding current, arc voltage and welding speed were chosen as variables parameters. The strength of each specimen after the welding operations were tested and the effects of these parameters on tensile strength were identified by using Taguchi method. The range of parameter for welding current were chosen from 100 to 115 A, arc voltage from 17 to 20 V and welding speed from 2 to 5 mm/s. L16 orthogonal array was used to obtained 16 runs of experiments. It was found that the highest tensile strength (194.34 MPa) was obtained with the combination of a welding current of 115 A, welding voltage of 18 V and welding speed of 4 mm/s. Through analysis of variance (ANOVA), the welding voltage was the most effected parameter on tensile strength with percentage of contribution at 41.30%.

  2. Evaluation of Various Depainting Processes on Mechanical Properties of 2024-T3 Aluminum Substrate

    NASA Technical Reports Server (NTRS)

    McGill, P.

    2001-01-01

    Alternate alkaline and neutral chemical paint strippers have been identified that, with respect to corrosion requirements, perform as well as or better than a methylene chloride baseline. These chemicals also, in general, meet corrosion acceptance criteria as specified in SAE MA 4872. Alternate acid chemical paint strippers have been identified that, with respect to corrosion requirements, perform as well as or better than a methylene chloride baseline. However, these chemicals do not generally meet corrosion acceptance criteria as specified in SAE MA 4872, especially in the areas of non-clad material performance and hydrogen embrittlement. Media blast methods reviewed in the study do not, in general, adversely affect fatigue performance or crack detectability of 2024-T3 substrate. Sodium bicarbonate stripping exhibited a tendency towards inhibiting crack detectability. These generalizations are based on a limited sample size and additional testing should be performed to characterize the response of specific substrates to specific processes.

  3. Improvement on the Fatigue Performance of 2024-T4 Alloy by Synergistic Coating Technology

    PubMed Central

    Wang, Xi-Shu; Guo, Xing-Wu; Li, Xu-Dong; Ge, Dong-Yun

    2014-01-01

    In this paper, rotating bending fatigue tests of 2024-T4 Al alloy with different oxide coatings were carried out. Compared to the uncoated and previously reported oxide coatings of aluminum alloys, the fatigue strength is able to be enhanced by using a novel oxide coating with sealing pore technology. These results indicate that the better the coating surface quality is, the more excellent the fatigue performance under rotating bending fatigue loading is. The improvement on the fatigue performance is mainly because the fatigue crack initiation and the early stage of fatigue crack growth at the coating layer can be delayed after PEO coating with pore sealing. Therefore, it is a so-called synergistic coating technology for various uses, including welding thermal cracks and filling micro-pores. The effects of different oxide coatings on surface hardness, compressive residual stress, morphology and fatigue fracture morphology are discussed. A critical compressive residual stress of about 95–100 MPa is proposed. PMID:28788634

  4. Galvanic Couple Current and Potential Distribution between a Mg Electrode and 2024-T351 under Droplets Analyzed by Microelectrode Arrays

    DTIC Science & Technology

    2015-11-04

    cathodically to – 1.5 V vs. SCE in aearated NaCl solution dissolves at a rate as high as 4 mA/cm2. However, the same alloy was shown to avoid significant...MgRP coating could be utilized in place of the Mg electrode. It is well known that the wettability of the surface of aluminum and its oxides is high ...aluminum alloys , such as precipitation age hardened 2024-T351, and has performed well in field studies.1–13 The MgRP is designed to be applied to an

  5. Testing of stiffening ribs formed by incremental forming in thin-walled aircraft structures made of 2024-T3 ALCLAD aluminium alloy

    NASA Astrophysics Data System (ADS)

    Kubit, Andrzej; Wydrzynski, Dawid; Bucior, Magdalena; Krasowski, Bogdan

    2018-05-01

    This paper presents the results of experimental tests on the fabrication of longitudinal stiffening ribs in 2024-T3 ALCLAD aluminum alloy sheet, which is widely used in the aircraft structures. The problem presented in this paper concerns the concept of rib-stiffening of the structure of aircraft skin. The ribs are intended to stiffen integral thin-walled structure. Different shapes and different parameters of the forming process were studied. The rib-stiffened samples of various depths of the ribs were tested experimentally in the buckling test.

  6. 31 CFR 202.4 - Agreement of deposit.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Agreement of deposit. 202.4 Section 202.4 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE DEPOSITARIES AND FINANCIAL AGENTS OF THE FEDERAL...

  7. 31 CFR 202.4 - Agreement of deposit.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 2 2012-07-01 2012-07-01 false Agreement of deposit. 202.4 Section 202.4 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE DEPOSITARIES AND FINANCIAL AGENTS OF THE FEDERAL...

  8. Microstructural features of friction stir welded dissimilar Aluminium alloys AA2219-AA7475

    NASA Astrophysics Data System (ADS)

    Zaman Khan, Noor; Ubaid, Mohammed; Siddiquee, Arshad Noor; Khan, Zahid A.; Al-Ahmari, Abdulrahman; Chen, Xizhang; Haider Abidi, Mustufa

    2018-05-01

    High strength, good corrosion resistance, light weight make aluminium alloys a material of choice in many industrial sectors like aerospace, marine etc. Problems associated with welding of these alloys by fusion welding processes restricted their use in various industries. Friction stir welding (FSW), a clean solid-state joining process, easily overcomes various difficulties encountered during conventional fusion welding processes. In the present work, the effect of rotational speed (710 rpm, 900 rpm and 1120 rpm) on micro-hardness distribution and microstructure of FSWed dissimilar aluminium alloy joints were analyzed. Plates of AA7475-T761 and AA2219-O having thickness of 2.5 mm were welded by fixing AA7475 on retreating side (RS) and AA2219 on advancing side (AS). Welded joints were characterized by Vickers micro-hardness testing, scanning electron microscopy (SEM) and optical microscopy (OM). Results revealed that rotational speed significantly affects the micro-hardness due to increase in grain size, coarsening and dissolution of strengthening precipitates and re-precipitation. Higher micro-hardness values were observed in stir zone due to grain refinement and re-precipitation. Minimum micro-hardness value was observed at the TMAZ/HAZ of advancing side due to thermal softening.

  9. Electrochemical Properties of Organosilane Self Assembled Monolayers on Aluminum 2024

    NASA Technical Reports Server (NTRS)

    Hintze, Paul E.; Calle, Luz Marina

    2004-01-01

    Self assembled monolayers are commonly used to modify surfaces. Within the last 15 years, self assembled monolayers have been investigated as a way to protect from corrosion[1,2] or biofouling.[3] In this study, self assembled monolayers of decitriethoxysilane (C10H21Si(OC2H5)3) and octadecyltriethoxysilane (C18H37Si(OC2H5)3) were formed on aluminum 2024-T3. The modified surfaces and bare Al 2024 were characterized by dynamic water contact angle measurements, x-ray photoelectron spectroscopy (XIPS) and infrared spectroscopy. Electrochemical impedance spectroscopy (EIS) in 0.5 M NaCl was used to characterize the monolayers and evaluate their corrosion protection properties. The advancing water contact angle and infrared measurements show that the mono layers form a surface where the hydrocarbon chains are packed and oriented away from the surface, consistent with what is found in similar systems. The contact angle hysteresis measured in these systems is relatively large, perhaps indicating that the hydrocarbon chains are not as well packed as monolayers formed on other substrates. The results of the EIS measurements were modeled using a Randle's circuit modified by changing the capacitor to a constant phase element. The constant phase element values were found to characterize the monolayer. The capacitance of the monolayer modified surface starts lower than the bare Al 2024, but approaches values similar to the bare Al 2024 within 24 hours as the monolayer is degraded. The n values found for bare Al 2024 quickly approach the value of a true capacitor and are greater than 0.9 within hours after the start of exposure. For the monolayer modified structure, n can stay lower than 0.9 for a longer period of time. In fact, n for the monolayer modified surfaces is different from the bare surface even after the capacitance values have converged. This indicates that the deviation from ideal capacitance is the most sensitive indicator of the presence of the monolayer.

  10. Structure and corrosion behavior of sputter deposited cerium oxide based coatings with various thickness on Al 2024-T3 alloy substrates

    NASA Astrophysics Data System (ADS)

    Liu, Yuanyuan; Huang, Jiamu; Claypool, James B.; Castano, Carlos E.; O'Keefe, Matthew J.

    2015-11-01

    Cerium oxide based coatings from ∼100 to ∼1400 nm in thickness were deposited onto Al 2024-T3 alloy substrates by magnetron sputtering of a 99.99% pure CeO2 target. The crystallite size of CeO2 coatings increased from 15 nm to 46 nm as the coating thickness increased from ∼100 nm to ∼1400 nm. The inhomogeneous lattice strain increased from 0.36% to 0.91% for the ∼100 nm to ∼900 nm thick coatings and slightly decreased to 0.89% for the ∼1400 nm thick coating. The highest adhesion strength to Al alloy substrates was for the ∼210 nm thick coating, due to a continuous film coverage and low internal stress. Electrochemical measurements indicated that sputter deposited crystalline CeO2 coatings acted as physical barriers that provide good cathodic inhibition for Al alloys in saline solution. The ∼900 nm thick CeO2 coated sample had the best corrosion performance that increased the corrosion resistance by two orders magnitude and lowered the cathodic current density 30 times compared to bare Al 2024-T3 substrates. The reduced defects and exposed surface, along with suppressed charge mobility, likely accounts for the improved corrosion performance as coating thickness increased from ∼100 nm to ∼900 nm. The corrosion performance decreased for ∼1400 nm thick coatings due in part to an increase in coating defects and porosity along with a decrease in adhesion strength.

  11. Effect of the Microstructure on Diffusion Bonded AA5083, AA6082 and AA7075 Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Venugopal, S.; Mahendran, G.

    2018-05-01

    Rolled plates of aluminium alloys AA5083, AA6082 and AA7075 of 5 mm thickness are joined by diffusion bonding at varied parameters. The microstructure evolution of AA5083, AA6082 and AA7075 aluminium alloys is characterized by Transmission Electron Microscopy (TEM). Metallurgical investigations and mechanical tests are also performed to correlate the results of the TEM investigations with the mechanical properties of the produced diffusion bonded joints. It is observed that the bonding and shear strength of the alloys increase with the increase in bonding temperature, due to the diffusion of micro-constituents in the interface. High temperature enhances the uniform distribution of secondary phase particles and reduces pore formation/defects in the bonded joints.

  12. Longitudinal analysis of cartilage T2 relaxation times and joint degeneration in African American and Caucasian American women over an observation period of 6 years - data from the Osteoarthritis Initiative.

    PubMed

    Kretzschmar, M; Heilmeier, U; Yu, A; Joseph, G B; Liu, F; Solka, M; McCulloch, C E; Nevitt, M C; Link, T M

    2016-08-01

    To investigate the change in cartilage T2 values and structural degeneration in knee joints over 72 months in women of African American (AA) vs Caucasian American (CA) ethnicity. Knee 3T magnetic resonance imaging (MRIs) from baseline, 24, 48 and 72 months visits of 100 AA and 100 CA women from the Osteoarthritis Initiative (OAI) were assessed for cartilage T2 values and whole-organ magnetic resonance imaging (WORMS) score. Subjects were pair-matched by age, body mass index (BMI), Kellgren-Lawrence (KL) score, clinical site and subcohort within the OAI. We compared the rate of change in whole knee cartilage T2 values and WORMS cartilage, bone marrow edema pattern (BMEP) and meniscus scores between the two ethnic groups using mixed random effects models. At 24 and 48 months 60 subjects and at 72 months 45 subjects per group were available for analysis resulting in 38 complete pairs with data of all time points. Compared to CA, cartilage T2 values in AA increased at a significantly faster rate at baseline (AA: 0.45 ms/y, CA: 0.35 ms/y, P = 0.029) and averaged over 6 years (AA: 0.36 ms/y, CA: 0.27 ms/y, P = 0.039) with changes in both groups reaching a plateau by 48 months. Cartilage, meniscus and BMEP scores tended to increase in both groups during follow up, but rates of change did not differ by ethnicity. Cartilage T2 values increased faster over 72 months in AA than CA, however changes in WORMS cartilage, meniscus and BMEP scores did not differ. T2 values may be able to distinguish ethnicity-related differences of cartilage degeneration at an early stage before differences in structural joint degeneration appear. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  13. Effect of tool rotation speed on microstructure and tensile properties of FSW joints of 2024-T351 and 7075-T651 reinforced with SiC nano particle: The role of FSW single pass

    NASA Astrophysics Data System (ADS)

    Kumar, K. S. Anil; Murigendrappa, S. M.; Kumar, Hemantha; Shekhar, Himanshu

    2018-04-01

    Friction stir welding (FSW) dissimilar joints of aluminium alloys of 2024-T351 and 7075-T651 were produced by reinforcing silicon carbide nano particle (SiCNP) in the rectangular cut groove made on the adjoining surface of the two dissimilar alloy plates joined in the butt configuration. A FSW tool of taper threaded cylindrical shape is used for producing the FSW dissimilar joints reinforced with SiCNP in the weld nugget zone (WNZ) and to produce metal matrix nano composite (MMNC) at the WNZ. In the experimental investigation, the constant FSW tool traverse speed of 40 mm/min and tool plunge depth of 6.2 mm/min is kept as constant, while the FSW tool rotation speed was varied from 400 rpm to 1800 rpm. The effect continuous varying tool rotation speed range from 400 rpm to 1800 rpm along the weld length and on the distribution of SiCNP in WNZ is analysed by conducting macro and microstructure study using optical microscopy (OM) and scanning electron microscopy (SEM) provided with energy dispersive spectrometry (EDS). In the experimental investigation, the combination of continuous varying FSW tool rotation speed range from 900rpm to 1150 rpm, constant tool traverse speed range 40 mm/min and tool plunge depth of 6.2 mm results in defect free, proper distribution of SiCNP and highest tensile properties for the FSW dissimilar joints. The highest ultimate tensile strength (UTS) of 380 MPa and yield strength (YS) of 150 MPa was observed for the combination of FSW tool rotation speed of 1000 rpm and tool traverse speed of 40 mm/min. The increasing in FSW tool rotation speed above 1250 rpm results in non homogeneous distribution of SiCNP in WNZ, excessive flash in the weld crown area and shows decreasing tendency in the tensile properties of the FSW dissimilar weld joints produced with reinforcing the SiCNP in the WNZ.

  14. Corrosion Properties of Cryorolled AA2219 Friction Stir Welded Joints Using Different Tool Pin Profiles

    NASA Astrophysics Data System (ADS)

    Kamal Babu, K.; Panneerselvam, K.; Sathiya, P.; Noorul Haq, A.; Sundarrajan, S.; Mastanaiah, P.; Srinivasa Murthy, C. V.

    The purpose of this paper is to present the corrosion behavior of the Cryorolled (CR) material and its Friction Stir Welded joints. Due to the thermal cycles of Friction Stir Welding (FSW) process, the corrosion behavior of the material gets affected. Here, the cryorolling process was carried out on AA2219 alloy and CR material was joined by FSW process using four different pin tool profiles such as cylindrical, threaded cylindrical, square and hexagonal pin. The FSW joints were analyzed by corrosion resistance with the help of potentiodynamic polarization test with 3.5% NaCl solution. From the analysis, it is found that CR AA2219 material exhibits good corrosion resistance compared to the base AA2219 material, and also a hexagonal pin profile FSW joint exhibits high corrosion resistance. Among the weld joints created by four different tools, the lowest corrosion resistance was found in the cylindrical pin tool FSW welds. Further, the corroded samples were investigated through metallurgical investigations like OM, Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDX) and X-Ray Diffraction (XRD). It was found that the amount of dissolution of Al2Cu precipitate was present in the weld nugget. The amount of dissolution of Al2Cu precipitate is higher in the weld nugget produced by hexagonal pin tool. This is due to the enhancement of the corrosion resistance.

  15. Effect of Weld Tool Geometry on Friction Stir Welded AA2219-T87 Properties

    NASA Technical Reports Server (NTRS)

    Querin, Joseph A.; Schneider, Judy A.

    2008-01-01

    In this study, flat panels of AA2219-T87 were friction stir welded (FSWed) using weld tools with tapered pins The three pin geometries of the weld tools included: 0 (straight cylinder), 30 , and 60 angles on the frustum. For each weld tool geometry, the FSW process parameters were optimized to eliminate defects. A constant heat input was maintained while varying the process parameters of spindle rpm and travel speed. This provided a constant heat input for each FSW weld panel while altering the hot working conditions imparted to the workpiece. The resulting mechanical properties were evaluated from tensile test results of the FSW joint.

  16. Is the presence of AA amyloidosis associated with impaired coronary flow reserve?

    PubMed

    Bulut, Mustafa; Keles, Nursen; Caliskan, Zuhal; Kostek, Osman; Aksu, Feyza; Ozdil, Kamil; Akcakoyun, Mustafa; Demircioglu, Kenan; Yilmaz, Yusuf; Kanbay, Mehmet; Caliskan, Mustafa

    2016-08-01

    Systemic amyloid A protein (AA) amyloidosis may occur as a complication of many chronic inflammatory disorders. Patients receiving inadequate anti-inflammatory and immunosuppressive therapies have an increased risk of developing systemic AA amyloidosis. Inflammation plays a role in all stages and the thrombotic complications of atherosclerosis. In the absence of epicardial coronary stenosis, coronary flow reserve (CFR) reflects coronary microvascular dysfunction. In the present study, we hypothesized that amyloid advanced subclinical inflammation in chronic inflammatory diseases (CID) patients may further affect coronary microcirculation. Thirty-two patients with biopsy-diagnosed renal AA, 73 patients with non-amyloid CID, and a group of healthy volunteers were included in the study. The measurements of coronary flow velocity were performed by a single investigator with expertise in transthoracic Doppler harmonic echocardiography (TTDE). The AA amyloidosis subgroup had significantly lower CFR values than other non-amyloid CID patients and the control individuals (1.8 (1.5-2.1) vs. 2.1 (2.0-2.4) and 3.0 (2.8-3.2), p < 0.001). Multivariate logistic regression analysis indicated that the presence of AA amyloidosis and elevated hs - CRP independently predict impairment of the CFR (p < 0.05). The presence of AA amyloidosis is related to decreased CFR values and the presence of AA amyloidosis and elevated hs - CRP independently predict impairment of the CFR. Therefore, patients with AA amyloidosis may have an increased risk of developing coronary artery diseases. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Effect of Multipath Laser Shock Processing on Microhardness, Surface Roughness, and Wear Resistance of 2024-T3 Al Alloy

    PubMed Central

    Kadhim, Abdulhadi; Salim, Evan T.; Fayadh, Saeed M.; Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar

    2014-01-01

    Laser shock processing (LSP) is an innovative surface treatment technique with high peak power, short pulse, and cold hardening for strengthening metal materials. LSP is based on the application of a high intensity pulsed laser beam (I > 1 GW/cm2; t < 50 ns) at the interface between the metallic target and the surrounding medium (a transparent confining material, normally water) forcing a sudden vaporization of the metallic surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. The shock wave induces plastic deformation and a residual stress distribution in the target material. In this paper we study the increase of microhardness and surface roughness with the increase of laser pulse energy in 2024-T3 Al alloy. The influence of the thickness of the confining layer (water) on microhardness and surface roughness is also studied. In addition, the effect of LSP treatment with best conditions on wear behaviors of the alloy was investigated. PMID:24737973

  18. Effect of multipath laser shock processing on microhardness, surface roughness, and wear resistance of 2024-T3 Al alloy.

    PubMed

    Kadhim, Abdulhadi; Salim, Evan T; Fayadh, Saeed M; Al-Amiery, Ahmed A; Kadhum, Abdul Amir H; Mohamad, Abu Bakar

    2014-01-01

    Laser shock processing (LSP) is an innovative surface treatment technique with high peak power, short pulse, and cold hardening for strengthening metal materials. LSP is based on the application of a high intensity pulsed laser beam (I > 1 GW/cm(2); t < 50 ns) at the interface between the metallic target and the surrounding medium (a transparent confining material, normally water) forcing a sudden vaporization of the metallic surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. The shock wave induces plastic deformation and a residual stress distribution in the target material. In this paper we study the increase of microhardness and surface roughness with the increase of laser pulse energy in 2024-T3 Al alloy. The influence of the thickness of the confining layer (water) on microhardness and surface roughness is also studied. In addition, the effect of LSP treatment with best conditions on wear behaviors of the alloy was investigated.

  19. Co-expression of AaPMT and AaTRI effectively enhances the yields of tropane alkaloids in Anisodus acutangulus hairy roots

    PubMed Central

    2011-01-01

    Background Tropane alkaloids (TA) including anisodamine, anisodine, hyoscyamine and scopolamine are a group of important anticholinergic drugs with rapidly increasing market demand, so it is significant to improve TA production by biotechnological approaches. Putrescine N-methyltransferase (PMT) was considered as the first rate-limiting upstream enzyme while tropinone reductase I (TRI) was an important branch-controlling enzyme involved in TA biosynthesis. However, there is no report on simultaneous introduction of PMT and TRI genes into any TA-producing plant including Anisodus acutangulus (A. acutangulus), which is a Solanaceous perennial plant that is endemic to China and is an attractive resource plant for production of TA. Results In this study, 21 AaPMT and AaTRI double gene transformed lines (PT lines), 9 AaPMT single gene transformed lines (P lines) and 5 AaTRI single gene transformed lines (T lines) were generated. RT-PCR and real-time fluorescence quantitative analysis results revealed that total AaPMT (AaPMT T) and total AaTRI (AaTRI T) gene transcripts in transgenic PT, P and T lines showed higher expression levels than native AaPMT (AaPMT E) and AaTRI (AaTRI E) gene transcripts. As compared to the control and single gene transformed lines (P or T lines), PT transgenic hairy root lines produced significantly higher levels of TA. The highest yield of TA was detected as 8.104 mg/g dw in line PT18, which was 8.66, 4.04, and 3.11-times higher than those of the control (0.935 mg/g dw), P3 (highest in P lines, 2.004 mg/g dw) and T12 (highest in T lines, 2.604 mg/g dw), respectively. All the tested samples were found to possess strong radical scavenging capacity, which were similar to control. Conclusion In the present study, the co-expression of AaPMT and AaTRI genes in A. acutangulus hairy roots significantly improved the yields of TA and showed higher antioxidant activity than control because of higher total TA content, which is the first report on

  20. Administration of 3,5-diiodothyronine (3,5-T2) causes central hypothyroidism and stimulates thyroid-sensitive tissues.

    PubMed

    Padron, Alvaro Souto; Neto, Ruy Andrade Louzada; Pantaleão, Thiago Urgal; de Souza dos Santos, Maria Carolina; Araujo, Renata Lopes; de Andrade, Bruno Moulin; da Silva Leandro, Monique; de Castro, João Pedro Saar Werneck; Ferreira, Andrea Claudia Freitas; de Carvalho, Denise Pires

    2014-06-01

    In general, 3,5-diiodothyronine (3,5-T2) increases the resting metabolic rate and oxygen consumption, exerting short-term beneficial metabolic effects on rats subjected to a high-fat diet. Our aim was to evaluate the effects of chronic 3,5-T2 administration on the hypothalamus-pituitary-thyroid axis, body mass gain, adipose tissue mass, and body oxygen consumption in Wistar rats from 3 to 6 months of age. The rats were treated daily with 3,5-T2 (25, 50, or 75 μg/100 g body weight, s.c.) for 90 days between the ages of 3 and 6 months. The administration of 3,5-T2 suppressed thyroid function, reducing not only thyroid iodide uptake but also thyroperoxidase, NADPH oxidase 4 (NOX4), and thyroid type 1 iodothyronine deiodinase (D1 (DIO1)) activities and expression levels, whereas the expression of the TSH receptor and dual oxidase (DUOX) were increased. Serum TSH, 3,3',5-triiodothyronine, and thyroxine were reduced in a 3,5-T2 dose-dependent manner, whereas oxygen consumption increased in these animals, indicating the direct action of 3,5-T2 on this physiological variable. Type 2 deiodinase activity increased in both the hypothalamus and the pituitary, and D1 activities in the liver and kidney were also increased in groups treated with 3,5-T2. Moreover, after 3 months of 3,5-T2 administration, body mass and retroperitoneal fat pad mass were significantly reduced, whereas the heart rate and mass were unchanged. Thus, 3,5-T2 acts as a direct stimulator of energy expenditure and reduces body mass gain; however, TSH suppression may develop secondary to 3,5-T2 administration. © 2014 The authors.

  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. Constant and variable amplitude ultrasonic fatigue of 2024-T351 aluminium alloy at different load ratios.

    PubMed

    Mayer, H; Fitzka, M; Schuller, R

    2013-12-01

    Ultrasonic fatigue testing equipment is presented that is capable of performing constant amplitude (CA) and variable amplitude (VA) experiments at different constant load ratios. This equipment is used to study cyclic properties of aluminium alloy 2024-T351 in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regime at load ratios R=-1 and R=0.5. CA loading does not reveal a fatigue limit below 10¹⁰ cycles. Cracks leading to VHCF failure start at broken constituent particles. Specimens that survived more than 10¹⁰ cycles at R=-1 contain non-propagating cracks of lengths below grain size. Resonance frequency and nonlinearity parameter β(rel) show changes of vibration properties of specimens at low fractions of their VHCF lifetime. VA lifetimes are measured in the HCF and VHCF regime and compared with Miner calculations. Damage sums decrease with decreasing load (and increasing mean lifetimes) and are lower for R=0.5 than R=-1. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. 46 CFR 35.20-40 - Maneuvering characteristics-T/OC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Maneuvering characteristics-T/OC. 35.20-40 Section 35.20-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-40 Maneuvering characteristics—T/OC. For each ocean and coastwise tankship of 1,600 gross tons or...

  4. 46 CFR 32.56-35 - Doors-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Doors-T/ALL. 32.56-35 Section 32.56-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS... Doors—T/ALL. (a) Casing doors in category A machinery spaces and all elevator doors must be self-closing...

  5. 46 CFR 32.56-35 - Doors-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Doors-T/ALL. 32.56-35 Section 32.56-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS... Doors—T/ALL. (a) Casing doors in category A machinery spaces and all elevator doors must be self-closing...

  6. 46 CFR 32.40-35 - Hospital space-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Hospital space-T/ALL. 32.40-35 Section 32.40-35 Shipping... REQUIREMENTS Accommodations for Officers and Crew § 32.40-35 Hospital space—T/ALL. (a) Each vessel which in the... crew of 12 or more, must be provided with a hospital space. This space must be situated with due regard...

  7. 46 CFR 32.40-35 - Hospital space-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Hospital space-T/ALL. 32.40-35 Section 32.40-35 Shipping... REQUIREMENTS Accommodations for Officers and Crew § 32.40-35 Hospital space—T/ALL. (a) Each vessel which in the... crew of 12 or more, must be provided with a hospital space. This space must be situated with due regard...

  8. 46 CFR 32.40-35 - Hospital space-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Hospital space-T/ALL. 32.40-35 Section 32.40-35 Shipping... REQUIREMENTS Accommodations for Officers and Crew § 32.40-35 Hospital space—T/ALL. (a) Each vessel which in the... crew of 12 or more, must be provided with a hospital space. This space must be situated with due regard...

  9. 46 CFR 32.40-35 - Hospital space-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Hospital space-T/ALL. 32.40-35 Section 32.40-35 Shipping... REQUIREMENTS Accommodations for Officers and Crew § 32.40-35 Hospital space—T/ALL. (a) Each vessel which in the... crew of 12 or more, must be provided with a hospital space. This space must be situated with due regard...

  10. 46 CFR 32.40-35 - Hospital space-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Hospital space-T/ALL. 32.40-35 Section 32.40-35 Shipping... REQUIREMENTS Accommodations for Officers and Crew § 32.40-35 Hospital space—T/ALL. (a) Each vessel which in the... crew of 12 or more, must be provided with a hospital space. This space must be situated with due regard...

  11. The Disk and Jet of the Classical T Tauri Star AA Tau

    NASA Technical Reports Server (NTRS)

    Cox, A. W.; Grady, C. A.; Hamel, H.; Hornbeck, Jeremy; Russell, R.; Sitko, M.; Woodgate, B.

    2013-01-01

    Previous studies of the classical T Tauri star AA Tau have interpreted the UX Orionis-like photopolarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipolefield. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use the HST/STIS coronagraphic detection of the disk to measure the outer disk radius and inclination, and find that the inner disk is both misinclined and misaligned with respect to the outer disk. AA Tau drives a faint jet which is also misaligned with respect to the projection of the outer disk minor axis. The jet is also poorly collimated near the star. The measured inclination, 71+/-1deg, is above the inclination range suggested for stars with UX Orionis-like variability, indicating that dust grains in the disk have grown and settled toward the disk midplane.

  12. AA6082 to DX56-Steel Laser Brazing: Process Parameter-Intermetallic Formation Correlation

    NASA Astrophysics Data System (ADS)

    Narsimhachary, D.; Pal, S.; Shariff, S. M.; Padmanabham, G.; Basu, A.

    2017-09-01

    In the present study, laser-brazed AA6082 to DX56-galvanized steel joints were investigated to understand the influence of process parameters on joint strength in terms of intermetallic layer formation. 1.5-mm-thick sheet of aluminum alloy (AA6082-T6) and galvanized steel (DX56) sheet of 0.7 mm thickness were laser-brazed with 1.5-mm-diameter Al-12% Si solid filler wire. During laser brazing, laser power (4.6 kW) and wire feed rate (3.4 m/min) were kept constant with a varying laser scan speed of 3.5, 3, 2.5, 2, 1.5, and 1 m/min. Microstructure of brazed joint reveals epitaxial growth at the aluminum side and intermetallic layer formation at steel interface. Intermetallic layer formation was confirmed by EDS analysis and XRD study. Hardness profile showed hardness drop in filler region, and failure during tensile testing was initiated through the filler region near the steel interface. As per both experimental study and numerical analysis, it was observed that intermetallic layer thickness decreases with increasing brazing speed. Zn vaporization from galvanized steel interface also affected the joint strength. It was found that high laser scan speed or faster cooling rate can be chosen for suppressing intermetallic layer formation or at least decreasing the layer thickness which results in improved mechanical properties.

  13. Characteristic evaluation of process parameters of friction stir welding of aluminium 2024 hybrid composites

    NASA Astrophysics Data System (ADS)

    Sadashiva, M.; Shivanand, H. K.; Vidyasagar, H. N.

    2018-04-01

    The Current work is aimed to investigate the effect of process parameters in friction stir welding of Aluminium 2024 base alloy and Aluminium 2024 matrix alloy reinforced with E Glass and Silicon Carbide reinforcements. The process involved a set of synthesis techniques incorporating stir casting methodology resulting in fabrication of the composite material. This composite material that is synthesized is then machined to obtain a plate of dimensions 100 mm * 50 mm * 6 mm. The plate is then friction stir welded at different set of parameters viz. the spindle speed of 600 rpm, 900 rpm and 1200 rpm and feed rate of 40 mm/min, 80 mm/min and 120 mm/min for analyzing the process capability. The study of the given set of parameters is predominantly important to understand the physics of the process that may lead to better properties of the joint, which is very much important in perspective to its use in advanced engineering applications, especially in aerospace domain that uses Aluminium 2024 alloy for wing and fuselage structures under tension.

  14. Lessons from Distributing Eclipse Glasses: Planning Ahead for April 2024

    NASA Astrophysics Data System (ADS)

    Bartlett, Jennifer Lynn; Wilson, Teresa; Chizek Frouard, Malynda R.; Phlips, Alan

    2018-01-01

    In preparation for the 2017 August 21 total solar eclipse across the continental United States, a multifaceted effort encouraged safe public observation of this spectacular event. However, we experienced mixed results distributing free ISO 12312-2 compliant eclipse glasses.On the positive side, we successfully dispensed several hundred in Virginia through in-school programs about the eclipse. We created a 2017-eclipse information sheet to accompany a safe-viewing handout. To facilitate sending glasses home in student backpacks, we wrapped each pair in a double-sided flyer and sealed the bundle in an individual envelope. We also passed out glasses during evening and weekend activities at a planetarium. Religious, business, and educational groups were all excited to receive them as were co-workers, family, and friends.On the negative side, planetarium staff declined to give eclipse glasses to students without a parent due to safety and liability concerns. Then, a day camp returned 200 pairs less than 72 hours before the event for the same reasons. However, we also received several requests from groups that had waited until too late to be accommodated easily.During the week before the eclipse, demand for eclipse glasses in New York, Michigan, Indiana, Illinois, Wisconsin, Minnesota, South Dakota, Nebraska, and Missouri was less than anticipated. While many people were well prepared, the recalls and reported counterfeiting made others suspicious. Concurrently, vendors were offering their remaining stock for $1–10 each.The experiences of the 2017 total solar eclipse, both good and bad, will not completely fade before preparations for 2024 begin. We look forward enthusiastically to sharing that event with as many people as possible and hope that the overall distribution of eclipse glasses goes more smoothly.We thank the AAS for providing 1,000+ of the eclipse glasses we shared, which were donated to them by Google to promote the Eclipse Megamovie project; Rainbow

  15. Review and study of physics driven pitting corrosion modeling in 2024-T3 aluminum alloys

    NASA Astrophysics Data System (ADS)

    Yu, Lingyu; Jata, Kumar V.

    2015-04-01

    Material degradation due to corrosion and corrosion fatigue has been recognized to significantly affect the airworthiness of civilian and military aircraft, especially for the current fleet of airplanes that have served beyond their initial design life. The ability to predict the corrosion damage development in aircraft components and structures, therefore, is of great importance in managing timely maintenance for the aging aircraft vehicles and in assisting the design of new ones. The assessment of aircraft corrosion and its influence on fatigue life relies on appropriate quantitative models that can evaluate the initiation of the corrosion as well as the accumulation during the period of operation. Beyond the aircraft regime, corrosion has also affected the maintenance, safety and reliability of other systems such as nuclear power systems, steam and gas turbines, marine structures and so on. In the work presented in this paper, we reviewed and studied several physics based pitting corrosion models that have been reported in the literature. The classic work of particle induced pitting corrosion by Wei and Harlow is reviewed in detail. Two types of modeling, a power law based simplified model and a microstructure based model, are compared for 2024-T3 alloy. Data from literatures are used as model inputs. The paper ends with conclusions and recommendations for future work.

  16. 46 CFR 35.40-7 - Carbon dioxide alarm-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Carbon dioxide alarm-T/ALL. 35.40-7 Section 35.40-7... Requirements-TB/ALL. § 35.40-7 Carbon dioxide alarm—T/ALL. Adjacent to all carbon dioxide fire extinguishing... AT ONCE. CARBON DIOXIDE BEING RELEASED.” ...

  17. Characterization, Modeling, and Accelerating Emulation of Aircraft Coating Exposure and Degradation

    DTIC Science & Technology

    2009-09-30

    nucleation sites for conjugated polymer electrodeposition on AA 2024-T3. In particular, the role of secondary phase heterogeneities in the nucleation ...work is mainly contained in the MS Thesis of T. Chen, and was presented publicly on October 14, 2010 at the NACE Eastern Area Conference in

  18. 46 CFR 35.20-10 - Steering gear test-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Steering gear test-T/ALL. 35.20-10 Section 35.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-10 Steering gear test—T/ALL. On all tankships making voyages of more than 48 hours' duration, the entire...

  19. 46 CFR 35.20-10 - Steering gear test-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Steering gear test-T/ALL. 35.20-10 Section 35.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-10 Steering gear test—T/ALL. On all tankships making voyages of more than 48 hours' duration, the entire...

  20. 46 CFR 35.40-7 - Carbon dioxide alarm-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Carbon dioxide alarm-T/ALL. 35.40-7 Section 35.40-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Posting and Marking Requirements-TB/ALL. § 35.40-7 Carbon dioxide alarm—T/ALL. Adjacent to all carbon dioxide fire extinguishing...

  1. 46 CFR 35.20-5 - Draft of tankships-T/OC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Draft of tankships-T/OC. 35.20-5 Section 35.20-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-5 Draft of tankships—T/OC. The master of every tankship shall, whenever leaving port, enter the maximum draft of his...

  2. 46 CFR 35.20-5 - Draft of tankships-T/OC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Draft of tankships-T/OC. 35.20-5 Section 35.20-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-5 Draft of tankships—T/OC. The master of every tankship shall, whenever leaving port, enter the maximum draft of his...

  3. 46 CFR 35.20-5 - Draft of tankships-T/OC.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Draft of tankships-T/OC. 35.20-5 Section 35.20-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-5 Draft of tankships—T/OC. The master of every tankship shall, whenever leaving port, enter the maximum draft of his...

  4. 46 CFR 35.20-5 - Draft of tankships-T/OC.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Draft of tankships-T/OC. 35.20-5 Section 35.20-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-5 Draft of tankships—T/OC. The master of every tankship shall, whenever leaving port, enter the maximum draft of his...

  5. 46 CFR 35.20-5 - Draft of tankships-T/OC.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Draft of tankships-T/OC. 35.20-5 Section 35.20-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-5 Draft of tankships—T/OC. The master of every tankship shall, whenever leaving port, enter the maximum draft of his...

  6. Finite Element Simulation of Temperature and Strain Distribution during Friction Stir Welding of AA2024 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Jain, Rahul; Pal, Surjya Kanta; Singh, Shiv Brat

    2017-02-01

    Friction Stir Welding (FSW) is a solid state joining process and is handy for welding aluminum alloys. Finite Element Method (FEM) is an important tool to predict state variables of the process but numerical simulation of FSW is highly complex due to non-linear contact interactions between tool and work piece and interdependency of displacement and temperature. In the present work, a three dimensional coupled thermo-mechanical method based on Lagrangian implicit method is proposed to study the thermal history, strain distribution and thermo-mechanical process in butt welding of Aluminum alloy 2024 using DEFORM-3D software. Workpiece is defined as rigid-visco plastic material and sticking condition between tool and work piece is defined. Adaptive re-meshing is used to tackle high mesh distortion. Effect of tool rotational and welding speed on plastic strain is studied and insight is given on asymmetric nature of FSW process. Temperature distribution on the workpiece and tool is predicted and maximum temperature is found in workpiece top surface.

  7. 46 CFR 35.20-10 - Steering gear test-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Steering gear test-T/ALL. 35.20-10 Section 35.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-10 Steering gear test—T/ALL. On all tankships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means of...

  8. Antigen-Specific CD8 Lytic Phenotype Induced by Sipuleucel-T in Hormone-Sensitive or Castration-Resistant Prostate Cancer and Association With Overall Survival.

    PubMed

    Antonarakis, Emmanuel S; Small, Eric J; Petrylak, Daniel; Quinn, David I; Kibel, Adam S; Chang, Nancy; Dearstyne, Erica; Harmon, Matthew; Campogan, Dwayne; Haynes, Heather; Vu, Tuyen; Sheikh, Nadeem A; Drake, Charles G

    2018-06-01

    Sipuleucel-T is FDA-approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC) based on the IMPACT trial showing a 4.1-month benefit in median overall survival (OS) for patients receiving sipuleucel-T vs control. Although efficacy of sipuleucel-T is well-established, its mechanism remains incompletely understood. Patient samples from three sipuleucel-T trials were assessed for peripheral cellular immune responses to the immunogen PA2024 and the target antigen prostatic acid phosphatase (PAP). PAP- and PA2024-specific proliferative and cytolytic responses were characterized to delineate sipuleucel-T-induced immune responses. To quantify potential cytotoxic T lymphocyte (CTL) activity, cell-surface CD107a expression on PAP- or PA2024-specific CD8+ T cells was measured in sipuleucel-T-treated patient and healthy volunteer samples. Increased PA2024-specific CD4+ (p=0.030) and CD8+ (p=0.052) T-cell proliferation from baseline to week 6 was observed (N=14) post-sipuleucel-T, with greater magnitude of PA2024-specific responses compared to PAP. PAP- and PA2024-CTL activity (CD107a positivity) significantly increased at weeks 6 and 26 after sipuleucel-T treatment (p<0.0001; N=22). At 26 weeks post-sipuleucel-T, OS correlated with the magnitude of PAP (Pearson's R, 0.52; p=0.013) or PA2024 (Pearson's R, 0.67; p=0.0006) CTL activity. Higher PA2024-CTL activity at week 26 was significantly associated with longer OS using tertile analysis (p=0.0005; N=22), with PA2024 responses correlating with PAP responses at week 26 (R=0.90; p=1.53E -08 ). This study is the first to report PAP-specific CD8+ T-cell responses elicited by sipuleucel-T treatment. Increased and persistent potential PA2024-specific CTL activity correlated with PAP-specific CTL activity and associated with improved OS following sipuleucel-T treatment. Copyright ©2018, American Association for Cancer Research.

  9. Influence of FSW pin tool geometry on plastic flow of AA7075 T651

    NASA Astrophysics Data System (ADS)

    Lertora, Enrico; Mandolfino, Chiara; Gambaro, Carla

    2016-10-01

    In this paper the behaviour of the plastic flow during Friction Stir Welding of AA7075 T651 plates, realized with different shaped tools, has been investigated. In particular, the influence of the shape of three tools was studied using copper strips placed along the welds. After welding, radiography and metallurgical analysis were used in order to investigate the marker movement and its fragmentation.

  10. Analysing the Friction Stir Welded Joints of AA2219 Al-Cu Alloy in Different Heat-Treated-State

    NASA Astrophysics Data System (ADS)

    Venkateswarlu, D.; Cheepu, Muralimohan; Kranthi kumar, B.; Mahapatra, M. M.

    2018-03-01

    Aluminium alloy AA2219 is widely used in light weight structural applications where the good corrosion resistance and specific weight required. The fabrication of this alloy using friction stir welding process is gaining interest towards finding the characteristics of the weld metal properties, since this process involved in the welded materials does not melt and recast. In the present investigation, friction stir welding process was used for different heat treated conditions of 2219-T87 and 2219-T62 aluminium alloys to find the influence of base metal on characteristics of the joints. The experimental output results exhibited that, mechanical properties, weld metal characteristics and joint failure locations are significantly affected by the different heat treatment conditions of the substrate. The joints tensile and yield strength of the 2219-T87 welds was higher than the 2219-T62 welds. Hardness distribution in the stir zone was significantly varied between two different heat treaded material conditions. The microstructural features of the 2219-T62 welds reveal the coarse grains formation in the thermo-mechanically affected zone and heat affected zone. The joint efficiency of the 2219- T82 welds is 59.87%, while that of 2219-T62 welds is 39.10%. In addition, the elongation of the joint also varied and the joints failure location characteristics are different for two different types heat treated condition joints.

  11. The HLA-A2 Restricted T Cell Epitope HCV Core35–44 Stabilizes HLA-E Expression and Inhibits Cytolysis Mediated by Natural Killer Cells

    PubMed Central

    Nattermann, Jacob; Nischalke, Hans Dieter; Hofmeister, Valeska; Ahlenstiel, Golo; Zimmermann, Henning; Leifeld, Ludger; Weiss, Elisabeth H.; Sauerbruch, Tilman; Spengler, Ulrich

    2005-01-01

    Impaired activity of natural killer cells has been proposed as a mechanism contributing to viral persistence in hepatitis C virus (HCV) infection. Natural cytotoxicity is regulated by interactions of HLA-E with inhibitory CD94/NKG2A receptors on natural killer (NK) cells. Here, we studied whether HCV core encodes peptides that bind to HLA-E and inhibit natural cytotoxicity. We analyzed 30 HCV core-derived peptides. Peptide-induced stabilization of HLA-E expression was measured flow cytometrically after incubating HLA-E-transfected cells with peptides. NK cell function was studied with a 51chromium-release-assay. Intrahepatic HLA-E expression was analyzed by an indirect immunoperoxidase technique and flow cytometry of isolated cells using a HLA-E-specific antibody. We identified peptide aa35–44, a well-characterized HLA-A2 restricted T cell epitope, as a peptide stabilizing HLA-E expression and thereby inhibiting NK cell-mediated lysis. Blocking experiments confirmed that this inhibitory effect of peptide aa35–44 on natural cytotoxicity was mediated via interactions between CD94/NKG2A receptors and enhanced HLA-E expression. In line with these in vitro data we found enhanced intrahepatic HLA-E expression on antigen-presenting cells in HCV-infected patients. Our data indicate the existence of T cell epitopes that can be recognized by HLA-A2 and HLA-E. This dual recognition may contribute to viral persistence in hepatitis C. PMID:15681828

  12. 46 CFR 35.40-8 - Carbon dioxide warning signs-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Carbon dioxide warning signs-T/ALL. 35.40-8 Section 35.40-8 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Posting and Marking Requirements-TB/ALL § 35.40-8 Carbon dioxide warning signs—T/ALL. Each entrance to a space storing...

  13. 46 CFR 35.40-8 - Carbon dioxide warning signs-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Carbon dioxide warning signs-T/ALL. 35.40-8 Section 35... Marking Requirements-TB/ALL § 35.40-8 Carbon dioxide warning signs—T/ALL. Each entrance to a space storing carbon dioxide cylinders, a space protected by carbon dioxide systems, or any space into which carbon...

  14. 46 CFR 35.40-8 - Carbon dioxide warning signs-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Carbon dioxide warning signs-T/ALL. 35.40-8 Section 35... Marking Requirements-TB/ALL § 35.40-8 Carbon dioxide warning signs—T/ALL. Each entrance to a space storing carbon dioxide cylinders, a space protected by carbon dioxide systems, or any space into which carbon...

  15. 46 CFR 35.20-45 - Use of Auto Pilot-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Use of Auto Pilot-T/ALL. 35.20-45 Section 35.20-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-45 Use of Auto Pilot—T/ALL. Except as provided in 33 CFR 164.13, when the automatic pilot is used in: (a) Areas...

  16. 46 CFR 35.20-45 - Use of Auto Pilot-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Use of Auto Pilot-T/ALL. 35.20-45 Section 35.20-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-45 Use of Auto Pilot—T/ALL. Except as provided in 33 CFR 164.13, when the automatic pilot is used in: (a) Areas...

  17. 46 CFR 35.20-45 - Use of Auto Pilot-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Use of Auto Pilot-T/ALL. 35.20-45 Section 35.20-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-45 Use of Auto Pilot—T/ALL. Except as provided in 33 CFR 164.13, when the automatic pilot is used in: (a) Areas...

  18. 46 CFR 35.20-45 - Use of Auto Pilot-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Use of Auto Pilot-T/ALL. 35.20-45 Section 35.20-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-45 Use of Auto Pilot—T/ALL. Except as provided in 33 CFR 164.13, when the automatic pilot is used in: (a) Areas...

  19. 46 CFR 35.20-45 - Use of Auto Pilot-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Use of Auto Pilot-T/ALL. 35.20-45 Section 35.20-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-45 Use of Auto Pilot—T/ALL. Except as provided in 33 CFR 164.13, when the automatic pilot is used in: (a) Areas...

  20. CSI 2264: Probing the inner disks of AA Tauri-like systems in NGC 2264

    NASA Astrophysics Data System (ADS)

    McGinnis, P. T.; Alencar, S. H. P.; Guimarães, M. M.; Sousa, A. P.; Stauffer, J.; Bouvier, J.; Rebull, L.; Fonseca, N. N. J.; Venuti, L.; Hillenbrand, L.; Cody, A. M.; Teixeira, P. S.; Aigrain, S.; Favata, F.; Fűrész, G.; Vrba, F. J.; Flaccomio, E.; Turner, N. J.; Gameiro, J. F.; Dougados, C.; Herbst, W.; Morales-Calderón, M.; Micela, G.

    2015-05-01

    Context. The classical T Tauri star (CTTS) AA Tau has presented photometric variability that was attributed to an inner disk warp, caused by the interaction between the inner disk and an inclined magnetosphere. Previous studies of the young cluster NGC 2264 have shown that similar photometric behavior is common among CTTS. Aims: The goal of this work is to investigate the main causes of the observed photometric variability of CTTS in NGC 2264 that present AA Tau-like light curves, and verify if an inner disk warp could be responsible for their observed variability. Methods: In order to understand the mechanism causing these stars' photometric behavior, we investigate veiling variability in their spectra and u - r color variations and estimate parameters of the inner disk warp using an occultation model proposed for AA Tau. We also compare infrared Spitzer IRAC and optical CoRoT light curves to analyze the dust responsible for the occultations. Results: AA Tau-like variability proved to be transient on a timescale of a few years. We ascribe this variability to stable accretion regimes and aperiodic variability to unstable accretion regimes and show that a transition, and even coexistence, between the two is common. We find evidence of hot spots associated with occultations, indicating that the occulting structures could be located at the base of accretion columns. We find average values of warp maximum height of 0.23 times its radial location, consistent with AA Tau, with variations of on average 11% between rotation cycles. We also show that extinction laws in the inner disk indicate the presence of grains larger than interstellar grains. Conclusions: The inner disk warp scenario is consistent with observations for all but one star with AA Tau-like variability in our sample. AA Tau-like systems are fairly common, comprising 14% of CTTS observed in NGC 2264, though this number increases to 35% among systems of mass 0.7 M⊙ ≲ M ≲ 2.0 M⊙. Assuming random

  1. 46 CFR 35.40-17 - Foam hose/monitor stations-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Foam hose/monitor stations-T/ALL. 35.40-17 Section 35.40... Requirements-TB/ALL. § 35.40-17 Foam hose/monitor stations—T/ALL. (a) At each required foam hose/monitor valve there shall be marked in not less than 2-inch red letters and figures: “FOAM STATION 1,” 2, 3, etc. (b...

  2. 46 CFR 35.40-17 - Foam hose/monitor stations-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Foam hose/monitor stations-T/ALL. 35.40-17 Section 35.40... Requirements-TB/ALL. § 35.40-17 Foam hose/monitor stations—T/ALL. (a) At each required foam hose/monitor valve there shall be marked in not less than 2-inch red letters and figures: “FOAM STATION 1,” 2, 3, etc. (b...

  3. Uniform Corrosion and General Dissolution of Aluminum Alloys 2024-T3, 6061-T6, and 7075-T6

    NASA Astrophysics Data System (ADS)

    Huang, I.-Wen

    Uniform corrosion and general dissolution of aluminum alloys was not as well-studied in the past, although it was known for causing significant amount of weight loss. This work comprises four chapters to understand uniform corrosion of aluminum alloys 2024-T3, 6061-T6, and 7075-T6. A preliminary weight loss experiment was performed for distinguishing corrosion induced weight loss attributed to uniform corrosion and pitting corrosion. The result suggested that uniform corrosion generated a greater mass loss than pitting corrosion. First, to understand uniform corrosion mechanism and kinetics in different environments, a series of static immersion tests in NaCl solutions were performed to provide quantitative measurement of uniform corrosion. Thereafter, uniform corrosion development as a function of temperature, pH, Cl-, and time was investigated to understand the influence of environmental factors. Faster uniform corrosion rate has been found at lower temperature (20 and 40°C) than at higher temperature (60 and 80°C) due to accelerated corrosion product formation at high temperatures inhibiting corrosion reactions. Electrochemical tests including along with scanning electron microscopy (SEM) were utilized to study the temperature effect. Second, in order to further understand the uniform corrosion influence on pit growth kinetics, a long term exposures for 180 days in both immersion and ASTM-B117 test were performed. Uniform corrosion induced surface recession was found to have limited impact on pit geometry regardless of exposure methods. It was also found that the competition for limited cathodic current from uniform corrosion the primary rate limiting factor for pit growth. Very large pits were found after uniform corrosion growth reached a plateau due to corrosion product coverage. Also, optical microscopy and focused ion beam (FIB) imaging has provided more insights of distinctive pitting geometry and subsurface damages found from immersion samples and B117

  4. Joining sheet aluminum AA6061-T4 to cast magnesium AM60B by vaporizing foil actuator welding: Input energy, interface, and strength

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liu, Bert; Vivek, Anupam; Daehn, Glenn S.

    Dissimilar joining of sheet aluminum AA6061-T4 to cast magnesium AM60B was achieved by vaporizing foil actuator welding (VFAW). Three input energy levels were used (6, 8, and 10 kJ), and as a trend, higher input energies resulted in progressively higher flyer velocities, more pronounced interfacial wavy features, larger weld zones, higher peel strengths, and higher peel energies. In all cases, weld cross section revealed a soundly bonded interface characterized by well-developed wavy features and lack of voids and continuous layers of intermetallic compounds (IMCs). At 10 kJ input energy, flyer speed of 820 m/s, peel strength of 22.4 N/mm, andmore » peel energy of 5.2 J were obtained. In lap-shear, failure occurred in AA6061- T4 flyer at 97% of the base material’s peak tensile load. Peel samples failed along the weld interface, and the AM60B-side of the fracture surface showed thin, evenly-spaced lines of Al residuals which had been torn out of the base AA6061-T4 in a ductile fashion and transferred over to the AM60B side, indicating very strong AA6061-T4/AM60B bond in these areas. Furthermore, this work demonstrates VFAW’s capability in joining dissimilar lightweight metals such as Al/Mg, which is expected to be a great enabler in the ongoing push for vehicle weight reduction.« less

  5. Joining sheet aluminum AA6061-T4 to cast magnesium AM60B by vaporizing foil actuator welding: Input energy, interface, and strength

    DOE PAGES

    Liu, Bert; Vivek, Anupam; Daehn, Glenn S.

    2017-09-19

    Dissimilar joining of sheet aluminum AA6061-T4 to cast magnesium AM60B was achieved by vaporizing foil actuator welding (VFAW). Three input energy levels were used (6, 8, and 10 kJ), and as a trend, higher input energies resulted in progressively higher flyer velocities, more pronounced interfacial wavy features, larger weld zones, higher peel strengths, and higher peel energies. In all cases, weld cross section revealed a soundly bonded interface characterized by well-developed wavy features and lack of voids and continuous layers of intermetallic compounds (IMCs). At 10 kJ input energy, flyer speed of 820 m/s, peel strength of 22.4 N/mm, andmore » peel energy of 5.2 J were obtained. In lap-shear, failure occurred in AA6061- T4 flyer at 97% of the base material’s peak tensile load. Peel samples failed along the weld interface, and the AM60B-side of the fracture surface showed thin, evenly-spaced lines of Al residuals which had been torn out of the base AA6061-T4 in a ductile fashion and transferred over to the AM60B side, indicating very strong AA6061-T4/AM60B bond in these areas. Furthermore, this work demonstrates VFAW’s capability in joining dissimilar lightweight metals such as Al/Mg, which is expected to be a great enabler in the ongoing push for vehicle weight reduction.« less

  6. Treatment of AA amyloidosis in rheumatoid arthritis.

    PubMed

    Balakrishnan, C; Sule, A; Mittal, G; Gaitonde, S; Pathan, E; Rajadhyaksha, S; Deshpande, R B; Gurmeet, M; Samant, R; Joshi, V R

    2002-07-01

    Four patients of rheumatoid arthritis (RA) with biopsy confirmed AA amyloidosis were treated with chlorambucil. All had established but uncontrolled RA with a persistently raised ESR. Moderate (> 1 gm, < 3.5 gm/d) to nephrotic range (> 3.5 gm/d) proteinuria and a relatively well preserved renal function was noted in three patients. One patient had deranged renal function and required dialysis. On chlorambucil, there was complete recovery, partial improvement and no improvement in one patient each. The fourth patient required haemodialysis, did not tolerate chlorambucil and succumbed to the illness. Therapy with chlorambucil can benefit some patients of RA with AA amyloidosis. Leucopenia is the most important dose limiting side effect.

  7. Analysis of Lightweight Materials for the AM2 System

    DTIC Science & Technology

    2014-06-01

    and fatigue behavior in magnesium alloys . Materials Science & Engineering A (Structural Materials: Properties , Microstructure and Processing ), v 434...Table 7. Tensile properties of the alloys AA2024 or the T3 and T81 temper designations (Kuo et al . 2005...using a powder metallurgy technique, such as a standard cold compacting press and sintering process . However, the fatigue life of the liquid-based

  8. Semisolid Microstructural Evolution during Partial Remelting of a Bulk Alloy Prepared by Cold Pressing of the Ti-Al-2024Al Powder Mixture

    PubMed Central

    Qin, Yahong; Chen, Tijun; Wang, Yingjun; Zhang, Xuezheng; Li, Pubo

    2016-01-01

    A new method, powder thixoforming, has been proposed to fabricate an in situ Al3Tip/2024Al composite. During partial remelting, the microstructural evolution of the bulk alloy prepared by cold pressing of the Ti, Al, 2024Al powder mixture was investigated, and the formation mechanism of the Al3Ti particles produced by the reaction between the Ti powder and the Al alloy melt is also discussed in detail. The results indicate that the microstructural evolution of the 2024 alloy matrix can be divided into three stages: a rapid coarsening of the powder grains; a formation of primary α-Al particles surrounded with a continuous liquid film; and a slight coarsening of the primary α-Al particles. Simultaneously, a reaction layer of Al3Ti can be formed on the Ti powder surface when the bulk is heated for 10 min at 640 °C The thickness (X) of the reaction layer increases with the time according to the parabolic law of X=−0.43t2+4.21t+0.17. The stress generated in the reaction layer due to the volume dilatation can be calculated by using the equation σAl3Ti=−EAl3Ti6(1−υAl3Ti)t2Al3TitTi(1R−1R0). Comparing the obtained data with the results of the drip experiment, the reaction rate for the Ti powder and Al powder mixture is greater than that for the Ti plate and Al alloy mixture, respectively.

  9. Mechanical Properties and Microstructural Evolution of Friction-Stir-Welded Thin Sheet Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Cerri, Emanuela; Leo, Paola; Wang, Xiang; Embury, J. D.

    2011-05-01

    Friction stir welding of thin aluminum sheets represents a potential goal for aircraft and automotive industries because of the advantages of using this new technological process. In the current work, the microstructural evolution and mechanical behavior of 6082T6-6082T6, 2024T3-2024T3, and 6082T6-2024T3 thin friction-stir-welded joints were investigated. Uniaxial tensile testing at room temperature, 443 K, 473 K, and 503 K (170 °C, 200 °C, and 230 °C) was used to determine the extent to which these ultra-thin joints can be used and deformed. The tensile stress-strain curves showed a decrease of the flow stress with increasing temperature and decreasing strain rate. The ductility of 6082T6-6082T6 joints generally improved when deformed at warm temperatures. It was almost constant for the 6082T6-2024T3 and reached the higher value in the 2024T3-2024T3 when deformed at 443 K and 473 K (170 °C and 200 °C) when compared with the room temperature value. Tensile specimens fractured in the middle of the weld zone in a ductile mode. The precipitation and growth of S' type phases strengthens 2024T3-2024T3 joints during deformation. In the 6082T6-6082T6, β″ precipitates show some increase in size but give a lower contribution to strength. At 503 K (230 °C), recovery mechanisms (dislocation reorganization inside the deformed grains) are initiated but the temperature was not enough high to produce a homogeneous subgrain structure.

  10. Influence of surface pretreatments on the quality of trivalent chromium process coatings on aluminum alloy

    NASA Astrophysics Data System (ADS)

    Viroulaud, Rémi; Światowska, Jolanta; Seyeux, Antoine; Zanna, Sandrine; Tardelli, Joffrey; Marcus, Philippe

    2017-11-01

    The effects of surface pretreatments (degreasing and pickling) on the characteristics of the Trivalent Chromium Process (TCP) coating on pure aluminum and on AA2024-T351 aluminum alloy were investigated here by means of surface sensitive techniques: X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The XPS and ToF-SIMS results evidence that the TCP coating homogeneity is strongly dependent on the pretreatment process used. The TCP coverage factor, calculated from XPS results, is significantly lower, on both pure aluminum and AA2024-T351 alloy surface, when a pickling step is applied. One of the main effects of pickling pretreatment is strong metallic copper enrichment at the surface of the 2024 alloy, associated with chemical dissolution of Al-Cu intermetallic particles. However, it is evidenced here, that the copper enrichment is not detrimental for the quality of the TCP coating. The coating failure, observed when the pickling step is applied, can be assigned to a faster kinetics of the coating growth leading to formation of thicker conversion coating more susceptible to cracking or to the localized presence of aluminum fluoride species leading to the appearance of coating defects or detachment.

  11. Multiscale approach to micro/macro fatigue crack growth in 2024-T3 aluminum panel

    NASA Astrophysics Data System (ADS)

    Sih, G. C.

    2014-01-01

    When two contacting solid surfaces are tightly closed and invisible to the naked eye, the discontinuity is said to be microscopic regardless of whether its length is short or long. By this definition, it is not sufficient to distinguish the difference between a micro- and macro-crack by using the length parameter. Microcracks in high strength metal alloys have been known to be several centimeters or longer. Considered in this work is a dual scale fatigue crack growth model where the main crack can be micro or macro but there prevails an inherent microscopic tip region that is damaged depending on the irregularities of the microstructure. This region is referred to as the "micro-tip" and can be simulated by a sharp wedge with different angles in addition to mixed boundary conditions. The combination is sufficient to model microscopic entities in the form of voids, inclusions, precipitations, interfaces, in addition to subgrain imperfections, or cluster of dislocations. This is accomplished by using the method of "singularity representation" such that closed form asymptotic solutions can be obtained for the development of fatigue crack growth rate relations with three parameters. They include: (1) the crack surface tightness σ* represented by σ o/ σ ∞ = 0.3-0.5 for short cracks in region I, and 0.1-0.2 for long cracks in region II, (2) the micro/macro material properties reflected by the shear modulus ratio µ* (=µmicro/µmacro varying between 2 and 5) and (3) the most sensitive parameter d* being the micro-tip characteristic length d* (= d/ d o) whose magnitude decreases in the direction of region I→II. The existing fatigue crack growth data for 2024-T3 and 7075-T6 aluminum sheets are used to reinterpret the two-parameter d a/d N= C(Δ K) n relation where Δ K has now been re-derived for a microcrack with surfaces tightly in contact. The contact force will depend on the mean stress σm or mean stress ratio R as the primary parameter and on the stress

  12. Interleukin-35 administration counteracts established murine type 1 diabetes--possible involvement of regulatory T cells.

    PubMed

    Singh, Kailash; Kadesjö, Erik; Lindroos, Julia; Hjort, Marcus; Lundberg, Marcus; Espes, Daniel; Carlsson, Per-Ola; Sandler, Stellan; Thorvaldson, Lina

    2015-07-30

    The anti-inflammatory cytokine IL-35 is produced by regulatory T (Treg) cells to suppress autoimmune and inflammatory responses. The role of IL-35 in type 1 diabetes (T1D) remains to be answered. To elucidate this, we investigated the kinetics of Treg cell response in the multiple low dose streptozotocin induced (MLDSTZ) T1D model and measured the levels of IL-35 in human T1D patients. We found that Treg cells were increased in MLDSTZ mice. However, the Treg cells showed a decreased production of anti-inflammatory (IL-10, IL-35, TGF-β) and increased pro-inflammatory (IFN-γ, IL-2, IL-17) cytokines, indicating a phenotypic shift of Treg cells under T1D condition. IL-35 administration effectively both prevented development of, and counteracted established MLDSTZ T1D, seemingly by induction of Eos expression and IL-35 production in Treg cells, thus reversing the phenotypic shift of the Treg cells. IL-35 administration reversed established hyperglycemia in NOD mouse model of T1D. Moreover, circulating IL-35 levels were decreased in human T1D patients compared to healthy controls. These findings suggest that insufficient IL-35 levels play a pivotal role in the development of T1D and that treatment with IL-35 should be investigated in treatment of T1D and other autoimmune diseases.

  13. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All tankships... 46 Shipping 1 2012-10-01 2012-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section...

  14. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All tankships...

  15. 46 CFR 32.15-35 - Magnetic Compass and Gyrocompass-T/OC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Magnetic Compass and Gyrocompass-T/OC. 32.15-35 Section..., MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-35 Magnetic Compass and Gyrocompass—T/OC. (a) All tankships in ocean or coastwise service must be fitted with a magnetic compass. (b) All tankships...

  16. Synthesis and characterization of nanocrystalline Al 2024-B4C composite powders by mechanical alloying

    NASA Astrophysics Data System (ADS)

    Varol, T.; Canakci, A.

    2013-06-01

    In the present work, the effect of milling parameters on the morphology and microstructure of nanostructure Al2024-B4C composite powders obtained by mechanical alloying (MA) was studied. The effects of milling time and B4C content on the morphology, microstructure and particle size of nanostructure Al2024-B4C composite powders have been investigated. Different amounts of B4C particles (0, 5, 10 and 20 wt.%) were mixed with Al2024 powders and milled in a planetary ball mill for 30, 60, 120, 300, 420 and 600 min. Al 2024-B4C composite powders were characterized using a scanning electron microscope (SEM), laser particle-size analyzer, X-ray diffraction analysis (XRD) and the Vickers microhardness test. The results showed that the nanostructure Al2024-B4C composite powders were produced when they were milled for 600 min. The size of composite powder in the milled powder mixture was affected by the milling time and content of B4C particles. Moreover, it was observed that when MA reached a steady state, the properties of composite powders were stabilized.

  17. Imaging the Disk and Jet of the Classical T Tauri Star AA Tau

    NASA Astrophysics Data System (ADS)

    Cox, Andrew; Grady, C.; Hammel, H. B.; Hornbeck, J.; Russell, R. W.; Sitko, M. L.; Woodgate, B. E.

    2013-01-01

    Previous studies of the classical T Tauri star AA Tau have interpreted the UX Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use HST/STIS coronagraphic imagery to measure the V magnitude of the star for both STIS corona graphic observations, compare these data with optical photometry in the literature and find that unlike other classical T Tauri stars observed on the same HST program, the disk is most robustly detected at optical minimum light. We measure the outer disk radius, major axis position angle, and disk inclination, and find that the inner disk, as reported in the literature, is both mis-inclined and misaligned with respect to the outer disk. AA Tau drives a faint jet which is also misaligned with respect to the projection of the outer disk minor axis and which is poorly collimated near the star. The measured outer disk inclination, 71±1 degrees, is out of the inclination band suggested for stars with UX Orionis-like variability where no grain growth has occurred in the disk. The faintness of the disk, the small disk size, and visibility of the star and despite the high inclination, all indicate that the disk must have experienced grain growth and settling toward the disk midplane, which we verify by comparing the observed disk with model imagery from the literature.

  18. Evaluation of Fatigue Behavior and Surface Characteristics of Aluminum Alloy 2024 T6 After Electric Discharge Machining

    NASA Astrophysics Data System (ADS)

    Mehmood, Shahid; Shah, Masood; Pasha, Riffat Asim; Sultan, Amir

    2017-10-01

    The effect of electric discharge machining (EDM) on surface quality and consequently on the fatigue performance of Al 2024 T6 is investigated. Five levels of discharge current are analyzed, while all other electrical and nonelectrical parameters are kept constant. At each discharge current level, dog-bone specimens are machined by generating a peripheral notch at the center. The fatigue tests are performed on four-point rotating bending machine at room temperature. For comparison purposes, fatigue tests are also performed on the conventionally machined specimens. Linearized SN curves for 95% failure probability and with four different confidence levels (75, 90, 95 and 99%) are plotted for each discharge current level as well as for conventionally machined specimens. These plots show that the electric discharge machined (EDMed) specimens give inferior fatigue behavior as compared to conventionally machined specimen. Moreover, discharge current inversely affects the fatigue life, and this influence is highly pronounced at lower stresses. The EDMed surfaces are characterized by surface properties that could be responsible for change in fatigue life such as surface morphology, surface roughness, white layer thickness, microhardness and residual stresses. It is found that all these surface properties are affected by changing discharge current level. However, change in fatigue life by discharge current could not be associated independently to any single surface property.

  19. A study comparing changes in loading conditions of an extended service life system using aluminum 2024-T351

    NASA Astrophysics Data System (ADS)

    Beal, Roger Zack

    The current fiscally austere environment prevalent in the military and industry is driving extreme measures to save money. In the United States Air Force, this has driven enormous efforts to trim sustainment spending on extended life aircraft. The challenge to the aerospace engineer is to ensure flight safety in the midst of this economic pressure. One method of cutting costs is to increase the time an aircraft is in service by delaying the point when the aircraft is taken out of service for depot maintenance. To ensure flight safety, in depth fatigue and fracture analysis needs to be accomplished to assess increasing the inspection interval. The purpose of this study was to determine the sensitivity of Aluminum 2024-T351 alloy, a common material used in tension dominated aerospace applications, to two different loading spectra---one that is aggressive and the other that is benign. This was accomplished by conducting five different combinations of the two spectra, developing computer simulations using the AFGROW software and comparing with the measured data. The results showed that the material demonstrated significantly different behavior between the two spectra. These results provide a valuable tool for the aerospace engineer for fatigue life prediction and inspection interval evaluation.

  20. Stress Corrosion Cracking Behavior of Multipass TIG-Welded AA2219 Aluminum Alloy in 3.5 wt pct NaCl Solution

    NASA Astrophysics Data System (ADS)

    Venugopal, A.; Sreekumar, K.; Raja, V. S.

    2012-09-01

    The stress corrosion cracking (SCC) behavior of the AA2219 aluminum alloy in the single-pass (SP) and multipass (MP) welded conditions was examined and compared with that of the base metal (BM) in 3.5 wt pct NaCl solution using a slow-strain-rate technique (SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both the BM and welded joints. The results showed that the ductility ratio ( ɛ NaCl/( ɛ air) was 0.97 and 0.96, respectively, for the BM and MP welded joint, and the same was marginally reduced to 0.9 for the SP welded joint. The fractographic examination of the failed samples revealed a typical ductile cracking morphology for all the base and welded joints, indicating the good environmental cracking resistance of this alloy under all welded conditions. To understand the decrease in the ductility of the SP welded joint, preexposure SSRT followed by microstructural observations were made, which showed that the decrease in ductility ratio of the SP welded joint was caused by the electrochemical pitting that assisted the nucleation of cracks in the form of corrosion induced mechanical cracking rather than true SCC failure of the alloy. The microstructural examination and polarization tests demonstrated a clear grain boundary (GB) sensitization of the PMZ, resulting in severe galvanic corrosion of the SP weld joint, which initiated the necessary conditions for the localized corrosion and cracking along the PMZ. The absence of PMZ and a refined fusion zone (FZ) structure because of the lesser heat input and postweld heating effect improved the galvanic corrosion resistance of the MP welded joint greatly, and thus, failure occurred along the FZ.

  1. 46 CFR 35.10-1 - Emergency training, musters, and drills-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Emergency training, musters, and drills-T/ALL. 35.10-1... Emergency Requirements § 35.10-1 Emergency training, musters, and drills—T/ALL. Onboard training, musters, and drills must be in accordance with subchapter W (Lifesaving Appliances and Arrangements) of this...

  2. 46 CFR 35.10-1 - Emergency training, musters, and drills-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Emergency training, musters, and drills-T/ALL. 35.10-1... Emergency Requirements § 35.10-1 Emergency training, musters, and drills—T/ALL. Onboard training, musters, and drills must be in accordance with subchapter W (Lifesaving Appliances and Arrangements) of this...

  3. 46 CFR 35.10-1 - Emergency training, musters, and drills-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Emergency training, musters, and drills-T/ALL. 35.10-1... Emergency Requirements § 35.10-1 Emergency training, musters, and drills—T/ALL. Onboard training, musters, and drills must be in accordance with subchapter W (Lifesaving Appliances and Arrangements) of this...

  4. 46 CFR 35.10-1 - Emergency training, musters, and drills-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Emergency training, musters, and drills-T/ALL. 35.10-1... Emergency Requirements § 35.10-1 Emergency training, musters, and drills—T/ALL. Onboard training, musters, and drills must be in accordance with subchapter W (Lifesaving Appliances and Arrangements) of this...

  5. 46 CFR 35.10-1 - Emergency training, musters, and drills-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Emergency training, musters, and drills-T/ALL. 35.10-1... Emergency Requirements § 35.10-1 Emergency training, musters, and drills—T/ALL. Onboard training, musters, and drills must be in accordance with subchapter W (Lifesaving Appliances and Arrangements) of this...

  6. 46 CFR 35.10-5 - Muster lists, emergency signals, and manning-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Muster lists, emergency signals, and manning-T/ALL. 35.10-5 Section 35.10-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Fire and Emergency Requirements § 35.10-5 Muster lists, emergency signals, and manning—T/ALL. The requirements for muster lists, emergency signals, and...

  7. NGC 2024: Far-infrared and radio molecular observations

    NASA Technical Reports Server (NTRS)

    Thronson, H. A., Jr.; Lada, C. J.; Schwartz, P. R.; Smith, H. A.; Smith, J.; Glaccum, W.; Harper, D. A.; Loewenstein, R. F.

    1984-01-01

    Far infrared continuum and millimeter wave molecular observations are presented for the infrared and radio source NGC 2024. The measurements are obtained at relatively high angular resolution, enabling a description of the source energetics and mass distribution in greater detail than previously reported. The object appears to be dominated by a dense ridge of material, extended in the north/south direction and centered on the dark lane that is seen in visual photographs. Maps of the source using the high density molecules CS and HCN confirm this picture and allow a description of the core structure and molecular abundances. The radio molecular and infrared observations support the idea that an important exciting star in NGC 2024 has yet to be identified and is centered on the dense ridge about 1' south of the bright mid infrared source IRS 2. The data presented here allows a presentation of a model for the source.

  8. 46 CFR 35.40-7 - Carbon dioxide and clean agent alarms-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Carbon dioxide and clean agent alarms-T/ALL. 35.40-7 Section 35.40-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Posting and Marking Requirements-TB/ALL § 35.40-7 Carbon dioxide and clean agent alarms—T/ALL. Each carbon dioxide or clean agent fire extinguishing alarm...

  9. 46 CFR 35.10-15 - Emergency lighting and power systems-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Emergency lighting and power systems-T/ALL. 35.10-15... Emergency Requirements § 35.10-15 Emergency lighting and power systems—T/ALL. (a) Where fitted, it shall be the duty of the master to see that the emergency lighting and power systems are tested and inspected...

  10. 46 CFR 35.10-15 - Emergency lighting and power systems-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Emergency lighting and power systems-T/ALL. 35.10-15... Emergency Requirements § 35.10-15 Emergency lighting and power systems—T/ALL. (a) Where fitted, it shall be the duty of the master to see that the emergency lighting and power systems are tested and inspected...

  11. Differential clinical efficacy of anti-CD4 monoclonal antibodies in rat adjuvant arthritis is paralleled by differential influence on NF-κB binding activity and TNF-α secretion of T cells

    PubMed Central

    Pohlers, Dirk; Schmidt-Weber, Carsten B; Franch, Angels; Kuhlmann, Jürgen; Bräuer, Rolf; Emmrich, Frank; Kinne, Raimund W

    2002-01-01

    The aim of this study was to analyze the differential effects of three anti-CD4 monoclonal antibodies (mAbs) (with distinct epitope specifities) in the treatment of rat adjuvant arthritis (AA) and on T-cell function and signal transduction. Rat AA was preventively treated by intraperitoneal injection of the anti-CD4 mAbs W3/25, OX35, and RIB5/2 (on days -1, 0, 3, and 6, i.e. 1 day before AA induction, on the day of induction [day 0], and thereafter). The effects on T-cell reactivity in vivo (delayed-type hypersensitivity), ex vivo (ConA-induced proliferation), and in vitro (mixed lymphocyte culture) were assessed. The in vitro effects of anti-CD4 preincubation on T-cell receptor (TCR)/CD3-induced cytokine production and signal transduction were also analyzed. While preventive treatment with OX35 and W3/25 significantly ameliorated AA from the onset, treatment with RIB5/2 even accelerated the onset of AA by approximately 2 days (day 10), and ameliorated the arthritis only in the late phase (day 27). Differential clinical effects at the onset of AA were paralleled by a differential influence of the mAbs on T-cell functions, i.e. in comparison with OX35 and W3/25, the 'accelerating' mAb RIB5/2 failed to increase the delayed-type hypersentivity (DTH) to Mycobacterium tuberculosis, increased the in vitro tumor necrosis factor (TNF)-α secretion, and more strongly induced NF-κB binding activity after anti-CD4 preincubation and subsequent TCR/CD3-stimulation. Depending on their epitope specificity, different anti-CD4 mAbs differentially influence individual proinflammatory functions of T cells. This fine regulation may explain the differential efficacy in the treatment of AA and may contribute to the understanding of such treatments in other immunopathologies. PMID:12010568

  12. 28 CFR 20.24 - State laws on privacy and security.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Local Criminal History Record Information Systems § 20.24 State laws on privacy and security. Where a State originating criminal history record information provides for sealing or purging thereof, nothing...

  13. 28 CFR 20.24 - State laws on privacy and security.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Local Criminal History Record Information Systems § 20.24 State laws on privacy and security. Where a State originating criminal history record information provides for sealing or purging thereof, nothing...

  14. 28 CFR 20.24 - State laws on privacy and security.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Local Criminal History Record Information Systems § 20.24 State laws on privacy and security. Where a State originating criminal history record information provides for sealing or purging thereof, nothing...

  15. 28 CFR 20.24 - State laws on privacy and security.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Local Criminal History Record Information Systems § 20.24 State laws on privacy and security. Where a State originating criminal history record information provides for sealing or purging thereof, nothing...

  16. 28 CFR 20.24 - State laws on privacy and security.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Local Criminal History Record Information Systems § 20.24 State laws on privacy and security. Where a State originating criminal history record information provides for sealing or purging thereof, nothing...

  17. IMAGING THE DISK AND JET OF THE CLASSICAL T TAURI STAR AA TAU

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cox, Andrew W.; Grady, Carol A.; Hammel, Heidi B.

    2013-01-01

    Previous studies of the classical T Tauri star AA Tau have interpreted the UX-Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use Hubble Space Telescope (HST)/STIS coronagraphic imagery to measure the V magnitude of the star for both STIS coronagraphic observations, compare these data with optical photometry in the literature, and find that, unlike other classical T Tauri stars observed in the same HST program, the disk is most robustlymore » detected in scattered light at stellar optical minimum light. We measure the outer disk radius, 1.''15 {+-} 0.''10, major-axis position angle, and disk inclination and find that the inner disk, as reported in the literature, is both misinclined and misaligned with respect to the outer disk. AA Tau drives a faint jet, detected in both STIS observations and in follow-on Goddard Fabry-Perot imagery, which is also misaligned with respect to the projection of the outer disk minor axis and is poorly collimated near the star, but which can be traced 21'' from the star in data from 2005. The measured outer disk inclination, 71 Degree-Sign {+-} 1 Degree-Sign , is out of the range of inclinations suggested for stars with UX-Orionis-like variability when no grain growth has occurred in the disk. The faintness of the disk, small disk size, and detection of the star despite the high inclination all indicate that the dust disk must have experienced grain growth and settling toward the disk midplane, which we verify by comparing the observed disk with model imagery from the literature.« less

  18. Imaging the Disk and Jet of the Classical T Tauri Star AA Tau

    NASA Technical Reports Server (NTRS)

    Cox, Andrew W.; Grady, Carol A.; Hammel, Heidi B.; Hornbeck, Jeremy; Russell, Ray W.; Sitko, Michael L.; Woodgate, Bruce E.

    2013-01-01

    Previous studies of the classical T Tauri star AA Tau have interpreted the UX-Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use Hubble Space Telescope (HST)/STIS coronagraphic imagery to measure the V magnitude of the star for both STIS coronagraphic observations, compare these data with optical photometry in the literature, and find that, unlike other classical T Tauri stars observed in the same HST program, the disk is most robustly detected in scattered light at stellar optical minimum light.We measure the outer disk radius, 1 inch.15 plus-minus 0 inch.10, major-axis position angle, and disk inclination and find that the inner disk, as reported in the literature, is both misinclined and misaligned with respect to the outer disk. AA Tau drives a faint jet, detected in both STIS observations and in follow-on Goddard Fabry-Perot imagery, which is also misaligned with respect to the projection of the outer disk minor axis and is poorly collimated near the star, but which can be traced 21 inches from the star in data from 2005. The measured outer disk inclination, 71deg plus-minus 1deg, is out of the range of inclinations suggested for stars with UX-Orionis-like variability when no grain growth has occurred in the disk. The faintness of the disk, small disk size, and detection of the star despite the high inclination all indicate that the dust disk must have experienced grain growth and settling toward the disk midplane, which we verify by comparing the observed disk with model imagery from the literature.

  19. 50. Representative office, room 2024, second floor, Dwing, building 500, ...

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

    50. Representative office, room 2024, second floor, D-wing, building 500, looking west - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

  20. Microsolvation of the acetanilide cation (AA(+)) in a nonpolar solvent: IR spectra of AA(+)-L(n) clusters (L = He, Ar, N2; n ≤ 10).

    PubMed

    Schmies, Matthias; Patzer, Alexander; Schütz, Markus; Miyazaki, Mitsuhiko; Fujii, Masaaki; Dopfer, Otto

    2014-05-07

    Infrared photodissociation (IRPD) spectra of mass-selected cluster ions of acetanilide (N-phenylacetamide), AA(+)-Ln, with the ligands L = He (n = 1-2), Ar (n = 1-7), and N2 (n = 1-10) are recorded in the hydride stretch (amide A, νNH, νCH) and fingerprint (amide I-III) ranges of AA(+) in its (2)A'' ground electronic state. Cold AA(+)-Ln clusters are generated in an electron impact ion source, which predominantly produces the most stable isomer of a given cluster ion. Systematic vibrational frequency shifts of the N-H stretch fundamentals (νNH) provide detailed information about the sequential microsolvation process of AA(+) in a nonpolar (L = He and Ar) and quadrupolar (L = N2) solvent. In the most stable AA(+)-Ln clusters, the first ligand forms a hydrogen bond (H-bond) with the N-H proton of trans-AA(+) (t-AA(+)), whereas further ligands bind weakly to the aromatic ring (π-stacking). There is no experimental evidence for complexes with the less stable cis-AA(+) isomer. Quantum chemical calculations at the M06-2X/aug-cc-pVTZ level confirm the cluster growth sequence derived from the IR spectra. The calculated binding energies of De(H) = 720 and 1227 cm(-1) for H-bonded and De(π) = 585 and 715 cm(-1) for π-bonded Ar and N2 ligands in t-AA(+)-L are consistent with the observed photofragmentation branching ratios of AA(+)-Ln. Comparison between charged and neutral AA((+))-L dimers indicates that ionization switches the preferred ion-ligand binding motif from π-stacking to H-bonding. Electron removal from the HOMO of AA(+) delocalized over both the aromatic ring and the amide group significantly strengthens the C[double bond, length as m-dash]O bond and weakens the N-H bond of the amide group.

  1. A Western Corn Rootworm Cadherin-like Protein is not Involved in the Binding and Toxicity of Cry34/35Ab1 and Cry3Aa Bacillus Thuringiensis Proteins

    USDA-ARS?s Scientific Manuscript database

    The western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte is an important insect pest of corn. Bacillus thuringiensis (Bt) insecticidal proteins Cry3Aa (as mCry3A) and Cry34Ab1/Cry35Ab1 have been expressed in transgenic corn and are used to control the insect in the U.S. To date, there ...

  2. Dynamic Response of AA2519 Aluminum Alloy under High Strain Rates

    NASA Astrophysics Data System (ADS)

    Olasumboye, Adewale Taiwo

    Like others in the AA2000 series, AA2519 is a heat-treatable Al-Cu alloy. Its excellent ballistic properties and stress corrosion cracking resistance, combined with other properties, qualify it as a prime candidate for armored vehicle and aircraft applications. However, available data on its high strain-rate response remains limited. In this study, AA2519 aluminum alloy was investigated in three different temper conditions: T4, T6, and T8, to determine the effects of heat treatment on the microstructure and dynamic deformation behavior of the material at high strain rates ranging within 1000 ≤ epsilon ≤ 4000 s-1. Split Hopkinson pressure bar integrated with digital image correlation system was used for mechanical response characterization. Optical microscopy and scanning electron microscopy were used to assess the microstructure of the material after following standard metallographic specimen preparation techniques. Results showed heterogeneous deformation in the three temper conditions. It was observed that dynamic behavior in each condition was dependent on strength properties due to the aging type controlling the strengthening precipitates produced and initial microstructure. At 1500 s -1, AA2519-T6 exhibited peak dynamic yield strength and flow stress of 509 and 667 MPa respectively, which are comparable with what were observed in T8 condition at higher rate of 3500 s-1 but AA2519-T4 showed the least strength and flow stress properties. Early stress collapse, dynamic strain aging, and higher susceptibility to shear band formation and fracture were observed in the T6 condition within the selected range of high strain rates. The alloy's general mode of damage evolution was by dispersoid particle nucleation, shearing and cracking.

  3. Analysis of cooling media effects on microstructure and mechanical properties during FSW/UFSW of AA 6082-T6

    NASA Astrophysics Data System (ADS)

    Atif Wahid, Mohd; Siddiquee, Arshad Noor; Khan, Zahid A.; Sharma, Nidhi

    2018-04-01

    The aim of the present study is to investigate the effect of cooling media on the temperature distribution, microstructure and mechanical properties of the joint produced during Underwater Friction Stir Welding (UFSW) in normal water, cold water (water with crushed ice (CFSW)) and air (FSW), for aluminum alloy (AA) 6082-T6. The results showed that peak temperature during UFSW and CFSW were significantly lower than the FSW. The temperature at the advancing side (AS) of the joint was higher than the retreating side (RS). Substantial reduction in TMAZ/HAZ width was observed during UFSW and CFSW as compared to FSW. Al-Mn-Fe-Si intermetallic phases were seen in all the joints along with the BM. The main strengthening precipitates found in UFSW and CFSW was β″ (Mg5Si6) which changed to β (Mg2Si) precipitates during FSW due to increased temperature. The tensile strength of the joints was best during UFSW followed by FSW and CFSW. The controlled temperature distribution resulted in improved tensile strength whereas both undercooling and overcooling resulted in decreased tensile strength, however, increased cooling rate does not improve the elongation. A typical ‘W’ shape hardness profile was observed in all the joints irrespective of the cooling media used. Maximum hardness was obtained in the UFSW joint due to refined grain structure, high-density dislocations and presence of β″ phases.

  4. 46 CFR 35.10-5 - Muster lists, emergency signals, and manning-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Muster lists, emergency signals, and manning-T/ALL. 35... Fire and Emergency Requirements § 35.10-5 Muster lists, emergency signals, and manning—T/ALL. The requirements for muster lists, emergency signals, and manning must be in accordance with subchapter W...

  5. 46 CFR 35.10-5 - Muster lists, emergency signals, and manning-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Muster lists, emergency signals, and manning-T/ALL. 35... Fire and Emergency Requirements § 35.10-5 Muster lists, emergency signals, and manning—T/ALL. The requirements for muster lists, emergency signals, and manning must be in accordance with subchapter W...

  6. 46 CFR 35.10-5 - Muster lists, emergency signals, and manning-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Muster lists, emergency signals, and manning-T/ALL. 35... Fire and Emergency Requirements § 35.10-5 Muster lists, emergency signals, and manning—T/ALL. The requirements for muster lists, emergency signals, and manning must be in accordance with subchapter W...

  7. 46 CFR 35.10-5 - Muster lists, emergency signals, and manning-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Muster lists, emergency signals, and manning-T/ALL. 35... Fire and Emergency Requirements § 35.10-5 Muster lists, emergency signals, and manning—T/ALL. The requirements for muster lists, emergency signals, and manning must be in accordance with subchapter W...

  8. 3,5-Diiodo-L-Thyronine (3,5-T2) Exerts Thyromimetic Effects on Hypothalamus-Pituitary-Thyroid Axis, Body Composition, and Energy Metabolism in Male Diet-Induced Obese Mice

    PubMed Central

    Lietzow, Julika; Wohlgemuth, Franziska; Hoefig, Carolin S.; Wiedmer, Petra; Schweizer, Ulrich; Köhrle, Josef; Schürmann, Annette

    2015-01-01

    Effective and safe antiobesity drugs are still needed in face of the obesity pandemic worldwide. Recent interventions in rodents revealed 3,5-diiodo-L-thyronine (3,5-T2) as a metabolically active iodothyronine affecting energy and lipid metabolism without thyromimetic side effects typically associated with T3 administration. Accordingly, 3,5-T2 has been proposed as a potential hypolipidemic agent for treatment of obesity and hepatic steatosis. In contrast to other observations, our experiments revealed dose-dependent thyromimetic effects of 3,5-T2 akin to those of T3 in diet-induced obese male C57BL/6J mice. 3,5-T2 treatment exerted a negative feedback regulation on the hypothalamus-pituitary-thyroid axis, similar to T3. This is demonstrated by decreased expression of genes responsive to thyroid hormones (TH) in pituitary resulting in a suppressed thyroid function with lower T4 and T3 concentrations in serum and liver of 3,5-T2-treated mice. Analyses of hepatic TH target genes involved in lipid metabolism revealed T3-like changes in gene expression and increased type I-deiodinase activity after application of 3,5-T2 (2.5 μg/g body weight). Reduced hepatic triglyceride and serum cholesterol concentrations reflected enhanced lipid metabolism. Desired increased metabolic rate and reduction of different fat depots were, however, compromised by increased food intake preventing significant body weight loss. Moreover, enlarged heart weights indicate potential cardiac side effects of 3,5-T2 beyond hepatic thyromimetic actions. Altogether, the observed thyromimetic effects of 3,5-T2 in several mouse TH target tissues raise concern about indiscriminate administration of 3,5-T2 as powerful natural hormone for the treatment of hyperlipidemia and pandemic obesity. PMID:25322465

  9. 3,5-Diiodo-L-thyronine (3,5-t2) exerts thyromimetic effects on hypothalamus-pituitary-thyroid axis, body composition, and energy metabolism in male diet-induced obese mice.

    PubMed

    Jonas, Wenke; Lietzow, Julika; Wohlgemuth, Franziska; Hoefig, Carolin S; Wiedmer, Petra; Schweizer, Ulrich; Köhrle, Josef; Schürmann, Annette

    2015-01-01

    Effective and safe antiobesity drugs are still needed in face of the obesity pandemic worldwide. Recent interventions in rodents revealed 3,5-diiodo-L-thyronine (3,5-T2) as a metabolically active iodothyronine affecting energy and lipid metabolism without thyromimetic side effects typically associated with T3 administration. Accordingly, 3,5-T2 has been proposed as a potential hypolipidemic agent for treatment of obesity and hepatic steatosis. In contrast to other observations, our experiments revealed dose-dependent thyromimetic effects of 3,5-T2 akin to those of T3 in diet-induced obese male C57BL/6J mice. 3,5-T2 treatment exerted a negative feedback regulation on the hypothalamus-pituitary-thyroid axis, similar to T3. This is demonstrated by decreased expression of genes responsive to thyroid hormones (TH) in pituitary resulting in a suppressed thyroid function with lower T4 and T3 concentrations in serum and liver of 3,5-T2-treated mice. Analyses of hepatic TH target genes involved in lipid metabolism revealed T3-like changes in gene expression and increased type I-deiodinase activity after application of 3,5-T2 (2.5 μg/g body weight). Reduced hepatic triglyceride and serum cholesterol concentrations reflected enhanced lipid metabolism. Desired increased metabolic rate and reduction of different fat depots were, however, compromised by increased food intake preventing significant body weight loss. Moreover, enlarged heart weights indicate potential cardiac side effects of 3,5-T2 beyond hepatic thyromimetic actions. Altogether, the observed thyromimetic effects of 3,5-T2 in several mouse TH target tissues raise concern about indiscriminate administration of 3,5-T2 as powerful natural hormone for the treatment of hyperlipidemia and pandemic obesity.

  10. In silico cloning and B/T cell epitope prediction of triosephosphate isomerase from Echinococcus granulosus.

    PubMed

    Wang, Fen; Ye, Bin

    2016-10-01

    Cystic echinococcosis is a worldwide zoonosis caused by Echinococcus granulosus. Because the methods of diagnosis and treatment for cystic echinococcosis were limited, it is still necessary to screen target proteins for the development of new anti-hydatidosis vaccine. In this study, the triosephosphate isomerase gene of E. granulosus was in silico cloned. The B cell and T cell epitopes were predicted by bioinformatics methods. The cDNA sequence of EgTIM was composition of 1094 base pairs, with an open reading frame of 753 base pairs. The deduced amino acid sequences were composed of 250 amino acids. Five cross-reactive epitopes, locating on 21aa-35aa, 43aa-57aa, 94aa-107aa, 115-129aa, and 164aa-183aa, could be expected to serve as candidate epitopes in the development of vaccine against E. granulosus. These results could provide bases for gene cloning, recombinant expression, and the designation of anti-hydatidosis vaccine.

  11. Acoustic emission monitoring of tensile testing of corroded and un-corroded clad aluminum 2024-T3 and characterization of effects of corrosion on AE source events and material tensile properties

    NASA Astrophysics Data System (ADS)

    Okafor, A. Chukwujekwu; Natarajan, Shridhar

    2014-02-01

    Corrosion damage affects structural integrity and deteriorates material properties of aluminum alloys in aircraft structures. Acoustic Emission (AE) is an effective nondestructive evaluation (NDE) technique for monitoring such damages and predicting failure in large structures of an aircraft. For successful interpretation of data from AE monitoring, sources of AE and factors affecting it need to be identified. This paper presents results of AE monitoring of tensile testing of corroded and un-corroded clad Aluminum 2024-T3 test specimens, and characterization of the effects of strain-rate and corrosion damage on material tensile properties and AE source events. Effect of corrosion was studied by inducing corrosion in the test specimens by accelerated corrosion testing in a Q-Fog accelerated corrosion chamber for 12 weeks. Eight (8) masked dog-bone shaped specimens were placed in the accelerated corrosion chamber at the beginning of the test. Two (2) dog-bone shaped specimens were removed from the corrosion chamber after exposure time of 3, 6, 9, and 12 weeks respectively, and subjected to tension testing till specimen failure along with AE monitoring, as well as two (2) reference samples not exposed to corrosion. Material tensile properties (yield strength, ultimate tensile strength, toughness, and elongation) obtained from tension test and AE parameters obtained from AE monitoring were analyzed and characterized. AE parameters increase with increase in exposure period of the specimens in the corrosive environment. Aluminum 2024-T3 is an acoustically silent material during tensile deformation without any damage. Acoustic emission events increase with increase of corrosion damage and with increase in strain rate above a certain value. Thus AE is suitable for structural health monitoring of corrosion damage. Ultimate tensile strength, toughness and elongation values decrease with increase of exposure period in corrosion chamber.

  12. Surface Finish and Residual Stresses Induced by Orthogonal Dry Machining of AA7075-T651

    PubMed Central

    Jomaa, Walid; Songmene, Victor; Bocher, Philippe

    2014-01-01

    The surface finish was extensively studied in usual machining processes (turning, milling, and drilling). For these processes, the surface finish is strongly influenced by the cutting feed and the tool nose radius. However, a basic understanding of tool/surface finish interaction and residual stress generation has been lacking. This paper aims to investigate the surface finish and residual stresses under the orthogonal cutting since it can provide this information by avoiding the effect of the tool nose radius. The orthogonal machining of AA7075-T651 alloy through a series of cutting experiments was performed under dry conditions. Surface finish was studied using height and amplitude distribution roughness parameters. SEM and EDS were used to analyze surface damage and built-up edge (BUE) formation. An analysis of the surface topography showed that the surface roughness was sensitive to changes in cutting parameters. It was found that the formation of BUE and the interaction between the tool edge and the iron-rich intermetallic particles play a determinant role in controlling the surface finish during dry orthogonal machining of the AA7075-T651 alloy. Hoop stress was predominantly compressive on the surface and tended to be tensile with increased cutting speed. The reverse occurred for the surface axial stress. The smaller the cutting feed, the greater is the effect of cutting speed on both axial and hoop stresses. By controlling the cutting speed and feed, it is possible to generate a benchmark residual stress state and good surface finish using dry machining. PMID:28788534

  13. Effect of Repair Welding on Electrochemical Corrosion and Stress Corrosion Cracking Behavior of TIG Welded AA2219 Aluminum Alloy in 3.5 Wt Pct NaCl Solution

    NASA Astrophysics Data System (ADS)

    Venugopal, A.; Sreekumar, K.; Raja, V. S.

    2010-12-01

    The stress corrosion cracking (SCC) behavior of AA2219 aluminum alloy in the as-welded (AW) and repair-welded (RW) conditions was examined and compared with that of the base metal (BM) in 3.5 wt pct NaCl solution using the slow strain rate technique (SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both BM and welded joints. The results show that the ductility ratio ( ɛ NaCl/( ɛ air)) of the BM was close to one (0.97) and reduced to 0.9 for the AW joint. This value further reduced to 0.77 after carrying out one repair welding operation. However, the RW specimen exhibited higher ductility than the single-weld specimens even in 3.5 wt pct NaCl solution. SSRT results obtained using pre-exposed samples followed by post-test metallographic observations clearly showed localized pitting corrosion along the partially melted zone (PMZ), signifying that the reduction in ductility ratio of both the AW and RW joints was more due to mechanical overload failure, caused by the localized corrosion and a consequent reduction in specimen thickness, than due to SCC. Also, the RW joint exhibited higher ductility than the AW joint both in air and the environment, although SCC index (SI) for the former is lower than that of the latter. Fractographic examination of the failed samples, in general, revealed a typical ductile cracking morphology for all the base and welded joints, indicating the good environmental cracking resistance of this alloy. Microstructural examination and polarization tests further demonstrate grain boundary melting along the PMZ, and that provided the necessary electrochemical condition for the preferential cracking on that zone of the weldment.

  14. 46 CFR 35.40-7 - Carbon dioxide and clean agent alarms-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Carbon dioxide and clean agent alarms-T/ALL. 35.40-7... Marking Requirements-TB/ALL § 35.40-7 Carbon dioxide and clean agent alarms—T/ALL. Each carbon dioxide or...: “WHEN ALARM SOUNDS VACATE AT ONCE. [CARBON DIOXIDE/CLEAN AGENT—as appropriate] BEING RELEASED.” [USCG...

  15. 46 CFR 35.40-7 - Carbon dioxide and clean agent alarms-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Carbon dioxide and clean agent alarms-T/ALL. 35.40-7... Marking Requirements-TB/ALL § 35.40-7 Carbon dioxide and clean agent alarms—T/ALL. Each carbon dioxide or...: “WHEN ALARM SOUNDS VACATE AT ONCE. [CARBON DIOXIDE/CLEAN AGENT—as appropriate] BEING RELEASED.” [USCG...

  16. PKC-Theta is a Novel SC35 Splicing Factor Regulator in Response to T Cell Activation.

    PubMed

    McCuaig, Robert Duncan; Dunn, Jennifer; Li, Jasmine; Masch, Antonia; Knaute, Tobias; Schutkowski, Mike; Zerweck, Johannes; Rao, Sudha

    2015-01-01

    Alternative splicing of nuclear pre-mRNA is essential for generating protein diversity and regulating gene expression. While many immunologically relevant genes undergo alternative splicing, the role of regulated splicing in T cell immune responses is largely unexplored, and the signaling pathways and splicing factors that regulate alternative splicing in T cells are poorly defined. Here, we show using a combination of Jurkat T cells, human primary T cells, and ex vivo naïve and effector virus-specific T cells isolated after influenza A virus infection that SC35 phosphorylation is induced in response to stimulatory signals. We show that SC35 colocalizes with RNA polymerase II in activated T cells and spatially overlaps with H3K27ac and H3K4me3, which mark transcriptionally active genes. Interestingly, SC35 remains coupled to the active histone marks in the absence of continuing stimulatory signals. We show for the first time that nuclear PKC-θ co-exists with SC35 in the context of the chromatin template and is a key regulator of SC35 in T cells, directly phosphorylating SC35 peptide residues at RNA recognition motif and RS domains. Collectively, our findings suggest that nuclear PKC-θ is a novel regulator of the key splicing factor SC35 in T cells.

  17. SEM and TEM characterization of the microstructure of post-compressed TiB2/2024Al composite.

    PubMed

    Guo, Q; Jiang, L T; Chen, G Q; Feng, D; Sun, D L; Wu, G H

    2012-02-01

    In the present work, 55 vol.% TiB(2)/2024Al composites were obtained by pressure infiltration method. Compressive properties of 55 vol.% TiB(2)/2024Al composite under the strain rates of 10(-3) and 1S(-1) at different temperature were measured and microstructure of post-compressed TiB(2)/2024Al composite was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). No trace of Al(3)Ti compound flake was found. TiB(2)-Al interface was smooth without significant reaction products, and orientation relationships ( [Formula: see text] and [Formula: see text] ) were revealed by HRTEM. Compressive strength of TiB(2)/2024Al composites decreased with temperature regardless of strain rates. The strain-rate-sensitivity of TiB(2)/2024Al composites increased with the increasing temperature. Fracture surface of specimens compressed at 25 and 250°C under 10(-3)S(-1) were characterized by furrow. Under 10(-3)S(-1), high density dislocations were formed in Al matrix when compressed at 25°C and dynamic recrystallization occurred at 250°C. Segregation of Mg and Cu on the subgrain boundary was also revealed at 550°C. Dislocations, whose density increased with temperature, were formed in TiB(2) particles under 1S(-1). Deformation of composites is affected by matrix, reinforcement and strain rate. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Purchase of a Raman and Photoluminescence Imaging System for Characterization of Advanced Electrochemical and Electronic Materials

    DTIC Science & Technology

    2016-01-05

    2015, Abstract #1092. The Role of Chromium (III) in the Corrosion Inhibition of AA2024-T3 By Trivalent Chromium Process Coatings by Greg Swain...to replace chromate conversion coatings and primers with more environmentally-friendly, non-chromated coatings. The Trivalent Chromium Process (TCP...coatings and primers with more environmentally-friendly, non-chromated coatings. The Trivalent Chromium Process (TCP) coating, originally developed

  19. Decreased interleukin 35 and CD4+EBI3+ T cells in patients with active systemic lupus erythematosus.

    PubMed

    Ouyang, Han; Shi, Yong-Bing; Liu, Zhi-Chun; Wang, Zhi; Feng, Sheng; Kong, Shu-Min; Lu, Ying

    2014-08-01

    Interleukin 35 (IL-35) is likely to contribute to the development of autoimmune diseases, as the Epstein-Barr virus-induced gene protein 3 (EBI3) is the specificity subunit of IL-35. Nevertheless, until recently, no studies have evaluated its role in systemic lupus erythematosus (SLE) in humans. The objective of this study was to investigate the serum IL-35 level and the percentage of CD4EBI3 T cells in the peripheral blood of patients with SLE and explore the roles of double-positive T cells and IL-35 in the pathogenesis of SLE and the effects of glucocorticoid on these roles. Fifty-five hospitalized patients with SLE were recruited, and 20 volunteers were enrolled as healthy controls. Serum IL-35 levels were measured by enzyme-linked immunosorbent assay, and the percentage of CD4EBI3 T cells was analyzed by flow cytometry. The serum IL-35 level and the percentage of CD4EBI3 T cells were significantly decreased in patients with active SLE compared with healthy controls and patients with inactive SLE. The serum IL-35 level and the percentage of CD4EBI3 T cells were negatively correlated with the SLE disease activity index. The percentages of CD4EBI3 T cells and serum IL-35 levels in 10 untreated patients with active SLE were increased at days l, 3, and 7 after the treatment with methylprednisolone (0.8 mg·kg·d) compared with the percentages before the treatment. These results demonstrate that abnormalities in IL-35 and CD4EBI3 T cells may play important roles in the pathogenesis of SLE; the percentage of double-positive T cells and the level of IL-35 are parameters for the evaluation of SLE activity and severity.

  20. 77 FR 3609 - Safety Zone; Gulf Intracoastal Waterway, Mile Marker 35.2 to Mile Marker 35.5, Larose, Lafourche...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-25

    ...-AA00 Safety Zone; Gulf Intracoastal Waterway, Mile Marker 35.2 to Mile Marker 35.5, Larose, Lafourche... establishing a temporary safety zone for the specified waters of the Gulf Intracoastal Waterway, Larose, Lafourche Parish, Louisiana. This temporary safety Zone is needed to protect the general public, vessels and...

  1. Parallel loss of nuclear-encoded mitochondrial aminoacyl-tRNA synthetases and mtDNA-encoded tRNAs in Cnidaria.

    PubMed

    Haen, Karri M; Pett, Walker; Lavrov, Dennis V

    2010-10-01

    Unlike most animal mitochondrial (mt) genomes, which encode a set of 22 transfer RNAs (tRNAs) sufficient for mt protein synthesis, those of cnidarians have only retained one or two tRNA genes. Whether the missing cnidarian mt-tRNA genes relocated outside the main mt chromosome or were lost remains unclear. It is also unknown what impact the loss of tRNA genes had on other components of the mt translational machinery. Here, we explored the nuclear genome of the cnidarian Nematostella vectensis for the presence of mt-tRNA genes and their corresponding mt aminoacyl-tRNA synthetases (mt-aaRS). We detected no candidates for mt-tRNA genes and only two mt-aaRS orthologs. At the same time, we found that all but one cytosolic aaRS appear to be targeted to mitochondria. These results indicate that the loss of mt-tRNAs in Cnidaria is genuine and occurred in parallel with the loss of nuclear-encoded mt-aaRS. Our phylogenetic analyses of individual aaRS revealed that although the nearly total loss of mt-aaRS is rare, aaRS gene deletion and replacement have occurred throughout the evolution of Metazoa.

  2. Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network

    PubMed Central

    De Filippis, Luigi Alberto Ciro; Serio, Livia Maria; Facchini, Francesco; Mummolo, Giovanni; Ludovico, Antonio Domenico

    2016-01-01

    A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration. PMID:28774035

  3. Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network.

    PubMed

    De Filippis, Luigi Alberto Ciro; Serio, Livia Maria; Facchini, Francesco; Mummolo, Giovanni; Ludovico, Antonio Domenico

    2016-11-10

    A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.

  4. In-Situ Synthetic TiB2 Particulate Reinforced Metal Matrix Composite Coating on AA2024 Aluminum Alloy by Laser Cladding Technology

    NASA Astrophysics Data System (ADS)

    Xu, Jiang; Kan, Yide; Liu, Wenjin

    In order to improve the wear resistance of aluminum alloy, in-situ synthesized TiB2 and Ti3B4 peritectic composite particulate reinforced metal matrix composite, formed on a 2024 aluminum alloy by laser cladding with a powder mixture of Fe-coated Boron, Ti and Al, was successfully achieved using 3-KW CW CO2 laser. The chemical composition, microstructure and phase structure of the composite clad coating were analyzed by energy dispersive X-ray spectroscopy (EDX), SEM, AFM and XRD. The typical microstructure of the composite coating is composed of TiB2, Ti3B4, Al3Ti, Al3Fe and α-Al. The surface hardness of cladding coating increases with the amount of added Fe-coated B and Ti powder which determines the amount of TiB2 and Ti3B4 peritectic composite particulate. The nanohardness and the elastic modulus at the interface of the TiB2 and Ti3B4 peritectic composite particulate/matrix were investigated using the nanoindentation technique. The results showed that the nanohardness and the reduced elastic modulus from the peritectic composite particulate to the matrix is a gradient distribution.

  5. Investigation of Three Analytical Hypothesis for Determining Material Creep Behavior under Varied Loads, with an Application to 2024-T3 Aluminum-Alloy Sheet in Tension at 400 F

    NASA Technical Reports Server (NTRS)

    Berkovits, Avraham

    1961-01-01

    Three existing hypotheses are formulated mathematically to estimate tensile creep strain under varied loads and constant temperature from creep data obtained under constant load and constant temperature. hypotheses investigated include the time-hardening, strain-hardening, and life-fraction rules. Predicted creep behavior is compared with data obtained from tensile creep tests of 2024-T3 aluminum-alloy sheet at 400 F under cyclic-load conditions. creep strain under varied loads is presented on the basis of an equivalent stress, derived from the life-fraction rule, which reduces the varied-load case to a constant-load problem. Creep strain in the region of interest for structural design and rupture times, determined from the hypotheses investigated, are in fair agreement with data in most cases, although calculated values of creep strain are generally greater than the experimental values because creep recovery is neglected in the calculations.

  6. Crack-tip-opening angle measurements and crack tunneling under stable tearing in thin sheet 2024-T3 aluminum alloy

    NASA Technical Reports Server (NTRS)

    Dawicke, D. S.; Sutton, M. A.

    1993-01-01

    The stable tearing behavior of thin sheets 2024-T3 aluminum alloy was studied for middle crack tension specimens having initial cracks that were: flat cracks (low fatigue stress) and 45 degrees through-thickness slant cracks (high fatigue stress). The critical crack-tip-opening angle (CTOA) values during stable tearing were measured by two independent methods, optical microscopy and digital image correlation. Results from the two methods agreed well. The CTOA measurements and observations of the fracture surfaces showed that the initial stable tearing behavior of low and high fatigue stress tests is significantly different. The cracks in the low fatigue stress tests underwent a transition from flat-to-slant crack growth, during which the CTOA values were high and significant crack tunneling occurred. After crack growth equal to about the thickness, CTOA reached a constant value of 6 deg and after crack growth equal to about twice the thickness, crack tunneling stabilized. The initial high CTOA values, in the low fatigue crack tests, coincided with large three-dimensional crack front shape changes due to a variation in the through-thickness crack tip constraint. The cracks in the high fatigue stress tests reach the same constant CTOA value after crack growth equal to about the thickness, but produced only a slightly higher CTOA value during initial crack growth. For crack growth on the 45 degree slant, the crack front and local field variables are still highly three-dimensional. However, the constant CTOA values and stable crack front shape may allow the process to be approximated with two-dimensional models.

  7. Double-sided laser beam welded T-joints for aluminum-lithium alloy aircraft fuselage panels: Effects of filler elements on microstructure and mechanical properties

    NASA Astrophysics Data System (ADS)

    Han, Bing; Tao, Wang; Chen, Yanbin; Li, Hao

    2017-08-01

    In the current work, T-joints consisting of 2.0 mm thick 2060-T8/2099-T83 aluminum-lithium alloys for aircraft fuselage panels have been fabricated by double-sided fiber laser beam welding with different filler wires. A new type wire CW3 (Al-6.2Cu-5.4Si) was studied and compared with conventional wire AA4047 (Al-12Si) mainly on microstructure and mechanical properties. It was found that the main combined function of Al-6.2%Cu-5.4%Si in CW3 resulted in considerable improvements especially on intergranular strength, hot cracking susceptibility and hoop tensile properties. Typical non-dendritic equiaxed zone (EQZ) was observed along welds' fusion boundary. Hot cracks and fractures during the load were always located within the EQZ, however, this typical zone could be restrained by CW3, effectively. Furthermore, changing of the main intergranular precipitated phase within the EQZ from T phase by AA4047 to T2 phase by CW3 also resulted in developments on microscopic intergranular reinforcement and macroscopic hoop tensile properties. In addition, bridging caused by richer substructure dendrites within CW3 weld's columnar zone resulted in much lower hot cracking susceptibility of the whole weld than AA4047.

  8. Development of an NPM1/MLF1 D-FISH probe set for the detection of t(3;5)(q25;q35) identified in patients with acute myeloid leukemia.

    PubMed

    Aypar, Umut; Knudson, Ryan A; Pearce, Kathryn E; Wiktor, Anne E; Ketterling, Rhett P

    2014-09-01

    The t(3;5)(q25;q35) NPM1/MLF1 fusion has an incidence of approximately 0.5% in acute myeloid leukemia (AML) and has an intermediate prognosis at diagnosis. We have developed a dual-color, dual-fusion fluorescence in situ hybridization (D-FISH) assay to detect fusion of the MLF1 and NPM1 genes. A blinded investigation was performed using 25 normal bone marrow specimens and 26 bone marrow samples from patients with one or more metaphases with a t(3;5)(q21-q25;q31-q35) or a der(5)t(3;5)(q21-q25;q31-q35) previously identified by chromosome analysis. Once unblinded, the results indicate our D-FISH method identified NPM1/MLF1 fusion in 15 of the 26 fully evaluated patient samples. Excluding three samples with a single abnormal t(3;5) metaphase, 15 of 17 (88%) patient samples with a balanced t(3;5) demonstrated NPM1/MLF1 fusion, and 0 of 6 patient samples with a der(5)t(3;5) demonstrated NPM1/MLF1 fusion, suggesting only the balanced form of this 3;5 translocation as observed by karyotype is associated with NPM1/MLF1 fusion. Overall, the FISH results demonstrated five different outcomes (NPM1/MLF1 fusion, MLF1 disruption, MLF1 duplication, NPM1 deletion, and normal), indicating significant molecular heterogeneity when the 3;5 translocation is identified. The development of this sensitive D-FISH strategy for the detection of NPM1/MLF1 fusion adds to the AML FISH testing repertoire and is effective in the detection of this translocation at diagnosis as well as monitoring residual disease in AML patients. Copyright © 2014 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  9. Cytotoxicity of Tumor Antigen Specific Human T Cells Is Unimpaired by Arginine Depletion

    PubMed Central

    Knies, Diana; Medenhoff, Sergej; Wabnitz, Guido; Luckner-Minden, Claudia; Feldmeyer, Nadja; Voss, Ralf-Holger; Kropf, Pascale; Müller, Ingrid; Conradi, Roland; Samstag, Yvonne; Theobald, Matthias; Ho, Anthony D.; Goldschmidt, Hartmut; Hundemer, Michael

    2013-01-01

    Tumor-growth is often associated with the expansion of myeloid derived suppressor cells that lead to local or systemic arginine depletion via the enzyme arginase. It is generally assumed that this arginine deficiency induces a global shut-down of T cell activation with ensuing tumor immune escape. While the impact of arginine depletion on polyclonal T cell proliferation and cytokine secretion is well documented, its influence on chemotaxis, cytotoxicity and antigen specific activation of human T cells has not been demonstrated so far. We show here that chemotaxis and early calcium signaling of human T cells are unimpaired in the absence of arginine. We then analyzed CD8+ T cell activation in a tumor peptide as well as a viral peptide antigen specific system: (i) CD8+ T cells with specificity against the MART-1aa26–35*A27L tumor antigen expanded with in vitro generated dendritic cells, and (ii) clonal CMV pp65aa495–503 specific T cells and T cells retrovirally transduced with a CMV pp65aa495–503 specific T cell receptor were analyzed. Our data demonstrate that human CD8+ T cell antigen specific cytotoxicity and perforin secretion are completely preserved in the absence of arginine, while antigen specific proliferation as well as IFN-γ and granzyme B secretion are severely compromised. These novel results highlight the complexity of antigen specific T cell activation and demonstrate that human T cells can preserve important activation-induced effector functions in the context of arginine deficiency. PMID:23717444

  10. 40 CFR 35.4075 - Are there things my group can't spend TAG money for?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Are there things my group can't spend... Can Pay For § 35.4075 Are there things my group can't spend TAG money for? Your TAG funds cannot be... other training expenses for your group's members or your technical advisor except as § 35.4070(b)(3...

  11. Optimization of the Mechanical Properties and Residual Stresses in 2024 Aluminum Alloy Through Heat Treatment

    NASA Astrophysics Data System (ADS)

    Araghchi, M.; Mansouri, H.; Vafaei, R.; Guo, Y.

    2018-05-01

    Residual stresses induced during quenching of aluminum alloys cause dimensional instability and distortion. In this study, the effects of different concentrations of polyalkylene glycol (PAG) quenchants on residual stresses and mechanical properties of 2024 aluminum alloy were investigated. Surface residual stresses were measured by using hole-drilling strain-gauge method. Also, mechanical properties and microstructure of the heat-treated samples were analyzed using hardness measurements, tensile tests, and transmission electron microscopy. Results showed that quenching into a 15% polymeric solution and aging at 190 °C for 12 h cause 50% reduction in residual stress as compared with quenching in water at 20 °C and naturally aging. Moreover, tensile strength decreased by 104 MPa ( 20%) in compared with the T6 sample.

  12. 35. MODEL T GASOLINE ENGINE. USED TO PUMP WATER FROM ...

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

    35. MODEL T GASOLINE ENGINE. USED TO PUMP WATER FROM THE ARTISAN WELL (THROUGH THE DOORWAY) TO THE CISTERN ON THE ROOF. WATER WAS THEN FED BY GRAVITY TO THE REST OF THE FACTORY. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  13. Overexpression of AaWRKY1 Leads to an Enhanced Content of Artemisinin in Artemisia annua.

    PubMed

    Jiang, Weimin; Fu, Xueqing; Pan, Qifang; Tang, Yueli; Shen, Qian; Lv, Zongyou; Yan, Tingxiang; Shi, Pu; Li, Ling; Zhang, Lida; Wang, Guofeng; Sun, Xiaofen; Tang, Kexuan

    2016-01-01

    Artemisinin is an effective component of drugs against malaria. The regulation of artemisinin biosynthesis is at the forefront of artemisinin research. Previous studies showed that AaWRKY1 can regulate the expression of ADS, which is the first key enzyme in artemisinin biosynthetic pathway. In this study, AaWRKY1 was cloned, and it activated ADSpro and CYPpro in tobacco using dual-LUC assay. To further study the function of AaWRKY1, pCAMBIA2300-AaWRKY1 construct under 35S promoter was generated. Transgenic plants containing AaWRKY1 were obtained, and four independent lines with high expression of AaWRKY1 were analyzed. The expression of ADS and CYP, the key enzymes in artemisinin biosynthetic pathway, was dramatically increased in AaWRKY1-overexpressing A. annua plants. Furthermore, the artemisinin yield increased significantly in AaWRKY1-overexpressing A. annua plants. These results showed that AaWRKY1 increased the content of artemisinin by regulating the expression of both ADS and CYP. It provides a new insight into the mechanism of regulation on artemisinin biosynthesis via transcription factors in the future.

  14. In Situ Formation of Decavanadate-Intercalated Layered Double Hydroxide Films on AA2024 and their Anti-Corrosive Properties when Combined with Hybrid Sol Gel Films

    PubMed Central

    Wu, Junsheng; Peng, Dongdong; He, Yuntao; Du, Xiaoqiong; Zhang, Zhan; Zhang, Bowei; Li, Xiaogang; Huang, Yizhong

    2017-01-01

    A layered double hydroxide (LDH) film was formed in situ on aluminum alloy 2024 through a urea hydrolysis method, and a decavanadate-intercalated LDH (LDH-V) film fabricated through the dip coating method. The microstructural and morphological characteristics were investigated by scanning electron microscopy (SEM). The corrosion-resistant performance was analyzed by electrochemical impedance spectroscopy (EIS), scanning electrochemical microscopy (SECM), and a salt-spray test (SST).The SEM results showed that a complete and defect-free surface was formed on the LDH-VS film. The anticorrosion results revealed that the LDH-VS film had better corrosion-resistant properties than the LDH-S film, especially long-term corrosion resistance. The mechanism of corrosion protection was proposed to consist of the self-healing effect of the decavanadate intercalation and the shielding effect of the sol-gel film. PMID:28772785

  15. 33 CFR 100.35T05-0276 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Marine Events; Potomac River, National Harbor Access Channel, MD. 100.35T05-0276 Section 100.35T05-0276... SAFETY OF LIFE ON NAVIGABLE WATERS § 100.35T05-0276 Special Local Regulations for Marine Events; Potomac... area: All waters of the Potomac River, within lines connecting the following positions: From 38°47′35...

  16. 33 CFR 100.35T05-0276 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Marine Events; Potomac River, National Harbor Access Channel, MD. 100.35T05-0276 Section 100.35T05-0276... SAFETY OF LIFE ON NAVIGABLE WATERS § 100.35T05-0276 Special Local Regulations for Marine Events; Potomac... area: All waters of the Potomac River, within lines connecting the following positions: From 38°47′35...

  17. Pyrrolysyl-tRNA Synthetase, an Aminoacyl-tRNA Synthetase for Genetic Code Expansion

    DOE PAGES

    Crnkovic, Ana; Suzuki, Tateki; Soll, Dieter; ...

    2016-06-14

    Genetic code expansion (GCE) has become a central topic of synthetic biology. GCE relies on engineered aminoacyl-tRNA synthetases (aaRSs) and a cognate tRNA species to allow codon reassignment by co-translational insertion of non-canonical amino acids (ncAAs) into proteins. Introduction of such amino acids increases the chemical diversity of recombinant proteins endowing them with novel properties. Such proteins serve in sophisticated biochemical and biophysical studies both in vitro and in vivo, they may become unique biomaterials or therapeutic agents, and they afford metabolic dependence of genetically modified organisms for biocontainment purposes. In the Methanosarcinaceae the incorporation of the 22nd genetically encodedmore » amino acid, pyrrolysine (Pyl), is facilitated by pyrrolysyl-tRNA synthetase (PylRS) and the cognate UAG-recognizing tRNAPyl. This unique aaRS•tRNA pair functions as an orthogonal translation system (OTS) in most model organisms. The facile directed evolution of the large PylRS active site to accommodate many ncAAs, and the enzyme’s anticodon-blind specific recognition of the cognate tRNAPyl make this system highly amenable for GCE purposes. The remarkable polyspecificity of PylRS has been exploited to incorporate >100 different ncAAs into proteins. Here we review the Pyl-OT system and selected GCE applications to examine the properties of an effective OTS.« less

  18. Construction of C35 gene bait recombinants and T47D cell cDNA library.

    PubMed

    Yin, Kun; Xu, Chao; Zhao, Gui-Hua; Liu, Ye; Xiao, Ting; Zhu, Song; Yan, Ge

    2017-11-20

    C35 is a novel tumor biomarker associated with metastasis progression. To investigate the interaction factors of C35 in its high expressed breast cancer cell lines, we constructed bait recombinant plasmids of C35 gene and T47D cell cDNA library for yeast two-hybrid screening. Full length C35 sequences were subcloned using RT-PCR from cDNA template extracted from T47D cells. Based on functional domain analysis, the full-length C35 1-348bp was also truncated into two fragments C351-153bp and C35154-348bp to avoid auto-activation. The three kinds of C35 genes were successfully amplified and inserted into pGBKT7 to construct bait recombinant plasmids pGBKT7-C351-348bp, pGBKT7-C351-153bp and pGBKT7-C35154-348bp, then transformed into Y187 yeast cells by the lithium acetate method. Auto-activation and toxicity of C35 baits were detected using nutritional deficient medium and X-α-Gal assays. The T47D cell ds cDNA was generated by SMART TM technology and the library was constructed using in vivo recombination-mediated cloning in the AH109 yeast strain using a pGADT7-Rec plasmid. The transformed Y187/pGBKT7-C351-348bp line was intensively inhibited while the truncated Y187/pGBKT7-C35 lines had no auto-activation and toxicity in yeast cells. The titer of established cDNA library was 2 × 10 7 pfu/mL with high transformation efficiency of 1.4 × 10 6 , and the insert size of ds cDNA was distributed homogeneously between 0.5-2.0 kb. Our research generated a T47D cell cDNA library with high titer, and the constructed two C35 "baits" contained a respective functional immunoreceptor tyrosine based activation motif (ITAM) and the conserved last four amino acids Cys-Ile-Leu-Val (CILV) motif, and therefore laid a foundation for screening the C35 interaction factors in a BC cell line.

  19. Transgenic pigeonpea events expressing Cry1Ac and Cry2Aa exhibit resistance to Helicoverpa armigera.

    PubMed

    Ghosh, Gourab; Ganguly, Shreeparna; Purohit, Arnab; Chaudhuri, Rituparna Kundu; Das, Sampa; Chakraborti, Dipankar

    2017-07-01

    Independent transgenic pigeonpea events were developed using two cry genes. Transgenic Cry2Aa-pigeonpea was established for the first time. Selected transgenic events demonstrated 100% mortality of Helicoverpa armigera in successive generations. Lepidopteran insect Helicoverpa armigera is the major yield constraint of food legume pigeonpea. The present study was aimed to develop H. armigera-resistant transgenic pigeonpea, selected on the basis of transgene expression and phenotyping. Agrobacterium tumefaciens-mediated transformation of embryonic axis explants of pigeonpea cv UPAS 120 was performed using two separate binary vectors carrying synthetic Bacillus thuringiensis insecticidal crystal protein genes, cry1Ac and cry2Aa. T 0 transformants were selected on the basis of PCR and protein expression profile. T 1 events were exclusively selected on the basis of expression and monogenic character for cry, validated through Western and Southern blot analyses, respectively. Independently transformed 12 Cry1Ac and 11 Cry2Aa single-copy events were developed. The level of Cry-protein expression in T 1 transgenic events was 0.140-0.175% of total soluble protein. Expressed Cry1Ac and Cry2Aa proteins in transgenic pigeonpea exhibited significant weight loss of second-fourth instar larvae of H. armigera and ultimately 80-100% mortality in detached leaf bioassay. Selected Cry-transgenic pigeonpea events, established at T 2 generation, inherited insect-resistant phenotype. Immunohistofluorescence localization in T 3 plants demonstrated constitutive accumulation of Cry1Ac and Cry2Aa in leaf tissues of respective transgenic events. This study is the first report of transgenic pigeonpea development, where stable integration, effective expression and biological activity of two Cry proteins were demonstrated in subsequent three generations (T 0 , T 1, and T 2 ). These studies will contribute to biotechnological breeding programmes of pigeonpea for its genetic improvement.

  20. Aa Ah Nak

    ERIC Educational Resources Information Center

    Tha, Na Gya; Wus, Thay

    2017-01-01

    In this article, Aa Ah Nak, the authors' methodology presents not only various reflections but also diverse contradictions about the Aa Nii language as well as language revitalization. This article explores language foundation and how the Aa Nii language revitalization is inextricably linked to the genocide and resulting historic trauma pervasive…

  1. Influence of groove size and reinforcements addition on mechanical properties and microstructure of friction stir welded joints

    NASA Astrophysics Data System (ADS)

    Reddy Baridula, Ravinder; Ibrahim, Abdullah Bin; Yahya, Che Ku Mohammad Faizal Bin Che Ku; Kulkarni, Ratnakar; Varma Ramaraju, Ramgopal

    2018-03-01

    The butt joints fabricated by friction stir welding were found to have more strength than the joints obtained by conventional joining process. The important outcome of this process is the successful fabrication of surface composites with improved properties. Thus in order to further enhance the strength of the dissimilar alloy joints the reinforcements can be deposited in to the aluminium matrix during the process of friction stir welding. In the present study the multi-walled carbon nanotubes were embedded in to the groove by varying the width during joining of dissimilar alloys AA2024 and AA7075. Four widths were selected with constant depth and optimum process parameters were selected to fabricate the sound welded joints. The results show that the mechanical properties of the fabricated butt joints were influenced by the size of the groove, due to variation in the deposition of reinforcement in the stir zone. The microstructural study and identification of the elements of the welded joints show that the reinforcements deposition is influenced by the size of the groove. It has also been observed that the groove with minimum width is more effective than higher width. The mechanical properties are found to be improved due to the pinning of grain boundaries.

  2. Pitting corrosion inhibition of aluminum 2024 by Bacillus biofilms secreting polyaspartate or gamma-polyglutamate.

    PubMed

    Ornek, D; Jayaraman, A; Syrett, B C; Hsu, C-H; Mansfeld, F B; Wood, T K

    2002-04-01

    Pitting corrosion of aluminum 2024 in Luria Bertani medium was reduced by the secretion of anionic peptides by engineered and natural Bacillus biofilms and was studied in continuous reactors using electrochemical impedance spectroscopy. Compared to sterile controls, pitting was reduced dramatically by the presence of the biofilms. The secretion of a 20 amino acid polyaspartate peptide by an engineered Bacillus subtilis WB600/pBE92-Asp biofilm slightly reduced the corrosion rate of the passive aluminum alloy at pH 6.5; however, the secretion of gamma-polyglutamate by a Bacillus licheniformis biofilm reduced the corrosion rate by 90% (compared to the B. subtilis WB600/pBE92 biofilm which did not secrete polyaspartate or gamma-polyglutamate). The corrosion potential ( E(corr)) of aluminum 2024 was increased by about 0.15-0.44 V due to the formation of B. subtilis and B. licheniformis biofilms as compared to sterile controls. The increase of E(corr) and the observed prevention of pitting indicate that the pitting potential ( E(pit)) had increased. This result and the further decrease of corrosion rates for the passive aluminum alloy suggest that the rate of the anodic metal dissolution reaction was reduced by an inhibitor produced by the biofilms. Purified gamma-polyglutamate also decreased the corrosion rates of aluminum 2024.

  3. Strengthening Mechanisms in Microtruss Metals

    NASA Astrophysics Data System (ADS)

    Ng, Evelyn K.

    Microtrusses are hybrid materials composed of a three-dimensional array of struts capable of efficiently transmitting an externally applied load. The strut connectivity of microtrusses enables them to behave in a stretch-dominated fashion, allowing higher specific strength and stiffness values to be reached than conventional metal foams. While much attention has been given to the optimization of microtruss architectures, little attention has been given to the strengthening mechanisms inside the materials that make up this architecture. This thesis examines strengthening mechanisms in aluminum alloy and copper alloy microtruss systems with and without a reinforcing structural coating. C11000 microtrusses were stretch-bend fabricated for the first time; varying internal truss angles were selected in order to study the accumulating effects of plastic deformation and it was found that the mechanical performance was significantly enhanced in the presence of work hardening with the peak strength increasing by a factor of three. The C11000 microtrusses could also be significantly reinforced with sleeves of electrodeposited nanocrystalline Ni-53wt%Fe. It was found that the strength increase from work hardening and electrodeposition were additive over the range of structures considered. The AA2024 system allowed the contribution of work hardening, precipitation hardening, and hard anodizing to be considered as interacting strengthening mechanisms. Because of the lower formability of AA2024 compared to C11000, several different perforation geometries in the starting sheet were considered in order to more effectively distribute the plastic strain during stretch-bend fabrication. A T8 condition was selected over a T6 condition because it was shown that the plastic deformation induced during the final step was sufficient to enhance precipitation kinetics allowing higher strengths to be reached, while at the same time eliminating one annealing treatment. When hard anodizing

  4. Metallurgical Effects of Shunting Current on Resistance Spot-Welded Joints of AA2219 Sheets

    NASA Astrophysics Data System (ADS)

    Jafari Vardanjani, M.; Araee, A.; Senkara, J.; Jakubowski, J.; Godek, J.

    2016-08-01

    Shunting effect is the loss of electrical current via the secondary circuit provided due to the existence of previous nugget in a series of welding spots. This phenomenon influences on metallurgical aspects of resistance spot-welded (RSW) joints in terms of quality and performance. In this paper RSW joints of AA2219 sheets with 1 mm thickness are investigated metallurgically for shunted and single spots. An electro-thermal finite element analysis is performed on the RSW process of shunted spot and temperature distribution and variation are obtained. These predictions are then compared with experimental micrographs. Three values of 5 mm, 20 mm, and infinite (i.e., single spot) are assumed for welding distance. Numerical and experimental results are matching each other in terms of nugget and HAZ geometry as increasing distance raised nugget size and symmetry of HAZ. In addition, important effect of shunting current on nugget thickness, microstructure, and Copper segregation on HAZ grain boundaries were discovered. A quantitative analysis is also performed about the influence of welding distance on important properties including ratio of nugget thickness and diameter ( r t), ratio of HAZ area on shunted and free side of nugget ( r HA), and ratio of equivalent segregated and total amount of Copper, measured in sample ( r Cu) on HAZ. Increasing distance from 5 mm to infinite, indicated a gain of 111.04, -45.55, and -75.15% in r t, r HA, and r Cu, respectively, while obtained ratios for 20 mm welding distance was suitable compared to single spot.

  5. A Multiple Aminoacyl-tRNA Synthetase Complex That Enhances tRNA-Aminoacylation in African Trypanosomes

    PubMed Central

    Cestari, Igor; Kalidas, Savitha; Monnerat, Severine; Anupama, Atashi; Phillips, Margaret A.

    2013-01-01

    The genes for all cytoplasmic and potentially all mitochondrial aminoacyl-tRNA synthetases (aaRSs) were identified, and all those tested by RNA interference were found to be essential for the growth of Trypanosoma brucei. Some of these enzymes were localized to the cytoplasm or mitochondrion, but most were dually localized to both cellular compartments. Cytoplasmic T. brucei aaRSs were organized in a multiprotein complex in both bloodstream and procyclic forms. The multiple aminoacyl-tRNA synthetase (MARS) complex contained at least six aaRS enzymes and three additional non-aaRS proteins. Steady-state kinetic studies showed that association in the MARS complex enhances tRNA-aminoacylation efficiency, which is in part dependent on a MARS complex-associated protein (MCP), named MCP2, that binds tRNAs and increases their aminoacylation by the complex. Conditional repression of MCP2 in T. brucei bloodstream forms resulted in reduced parasite growth and infectivity in mice. Thus, association in a MARS complex enhances tRNA-aminoacylation and contributes to parasite fitness. The MARS complex may be part of a cellular regulatory system and a target for drug development. PMID:24126051

  6. Projections of Education Statistics to 2024. Forty-Third Edition. NCES 2016-013

    ERIC Educational Resources Information Center

    Hussar, William J.; Bailey, Tabitha M.

    2016-01-01

    "Projections of Education Statistics to 2024" is the 43rd report in a series begun in 1964. It includes statistics on elementary and secondary schools and degree-granting postsecondary institutions. This report provides revisions of projections shown in Projections of Education Statistics to 2023 and projections of enrollment, graduates,…

  7. 33 CFR 100.35T09-0327 - Special Regulated Areas for summer events; Captain of the Port Lake Michigan Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Special Regulated Areas for summer events; Captain of the Port Lake Michigan Zone. 100.35T09-0327 Section 100.35T09-0327 Navigation... OF LIFE ON NAVIGABLE WATERS § 100.35T09-0327 Special Regulated Areas for summer events; Captain of...

  8. STS-35 Space Shuttle mission report

    NASA Technical Reports Server (NTRS)

    Camp, David W.; Germany, D. M.; Nicholson, Leonard S.

    1991-01-01

    The STS-35 Space Shuttle Program Mission Report contains a summary of the vehicle subsystem activities during this thirty-eighth flight of the Space Shuttle and the tenth flight of the Orbiter vehicle Columbia (OV-102). In addition to the Columbia vehicle, the flight vehicle consisted of an External Tank (ET) (designated as ET-35/LWT-28), three Space Shuttle main engines (SSME's) (serial numbers 2024, 2012, and 2028 in positions 1, 2, and 3, respectively), and two Solid Rocket Boosters (SRB's) designated as BI-038. The primary objectives of this flight were to successfully perform the planned operations of the Ultraviolet Astronomy (Astro-1) payload and the Broad-Band X-Ray Telescope (BBXRT) payload in a 190-nmi. circular orbit which had an inclination of 28.45 degrees. The sequence of events for this mission is shown in tablular form. Summarized are the significant problems that occurred in the Orbiter subsystems during the mission. The official problem tracking list is presented. In addition, each Orbiter subsystem problem is cited in the applicable subsystem discussion.

  9. Transgenic cotton expressing Cry10Aa toxin confers high resistance to the cotton boll weevil.

    PubMed

    Ribeiro, Thuanne Pires; Arraes, Fabricio Barbosa Monteiro; Lourenço-Tessutti, Isabela Tristan; Silva, Marilia Santos; Lisei-de-Sá, Maria Eugênia; Lucena, Wagner Alexandre; Macedo, Leonardo Lima Pepino; Lima, Janaina Nascimento; Santos Amorim, Regina Maria; Artico, Sinara; Alves-Ferreira, Márcio; Mattar Silva, Maria Cristina; Grossi-de-Sa, Maria Fatima

    2017-08-01

    Genetically modified (GM) cotton plants that effectively control cotton boll weevil (CBW), which is the most destructive cotton insect pest in South America, are reported here for the first time. This work presents the successful development of a new GM cotton with high resistance to CBW conferred by Cry10Aa toxin, a protein encoded by entomopathogenic Bacillus thuringiensis (Bt) gene. The plant transformation vector harbouring cry10Aa gene driven by the cotton ubiquitination-related promoter uceA1.7 was introduced into a Brazilian cotton cultivar by biolistic transformation. Quantitative PCR (qPCR) assays revealed high transcription levels of cry10Aa in both T 0 GM cotton leaf and flower bud tissues. Southern blot and qPCR-based 2 -ΔΔCt analyses revealed that T 0 GM plants had either one or two transgene copies. Quantitative and qualitative analyses of Cry10Aa protein expression showed variable protein expression levels in both flower buds and leaves tissues of T 0 GM cotton plants, ranging from approximately 3.0 to 14.0 μg g -1 fresh tissue. CBW susceptibility bioassays, performed by feeding adults and larvae with T 0 GM cotton leaves and flower buds, respectively, demonstrated a significant entomotoxic effect and a high level of CBW mortality (up to 100%). Molecular analysis revealed that transgene stability and entomotoxic effect to CBW were maintained in T 1 generation as the Cry10Aa toxin expression levels remained high in both tissues, ranging from 4.05 to 19.57 μg g -1 fresh tissue, and the CBW mortality rate remained around 100%. In conclusion, these Cry10Aa GM cotton plants represent a great advance in the control of the devastating CBW insect pest and can substantially impact cotton agribusiness. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  10. Effects of die quench forming on sheet thinning and 3-point bend testing of AA7075-T6

    NASA Astrophysics Data System (ADS)

    Kim, Samuel; Omer, Kaab; Rahmaan, Taamjeed; Butcher, Clifford; Worswick, Michael

    2017-10-01

    Lab-scaled AA7075 aluminum side impact beams were manufactured using the die quenching technique in which the sheet was solutionized and then quenched in-die during forming to a super saturated solid state. Sheet thinning measurements were taken at various locations throughout the length of the part and the effect of lubricant on surface scoring and material pick-up on the die was evaluated. The as-formed beams were subjected to a T6 aging treatment and then tested in three-point bending. Simulations were performed of the forming and mechanical testing experiments using the LS-DYNA finite element code. The thinning and mechanical response was predicted well.

  11. A Novel Tenebrio molitor Cadherin Is a Functional Receptor for Bacillus thuringiensis Cry3Aa Toxin*

    PubMed Central

    Fabrick, Jeff; Oppert, Cris; Lorenzen, Marcé D.; Morris, Kaley; Oppert, Brenda; Jurat-Fuentes, Juan Luis

    2009-01-01

    Cry toxins produced by the bacterium Bacillus thuringiensis are effective biological insecticides. Cadherin-like proteins have been reported as functional Cry1A toxin receptors in Lepidoptera. Here we present data that demonstrate that a coleopteran cadherin is a functional Cry3Aa toxin receptor. The Cry3Aa receptor cadherin was cloned from Tenebrio molitor larval midgut mRNA, and the predicted protein, TmCad1, has domain structure and a putative toxin binding region similar to those in lepidopteran cadherin B. thuringiensis receptors. A peptide containing the putative toxin binding region from TmCad1 bound specifically to Cry3Aa and promoted the formation of Cry3Aa toxin oligomers, proposed to be mediators of toxicity in lepidopterans. Injection of TmCad1-specific double-stranded RNA into T. molitor larvae resulted in knockdown of the TmCad1 transcript and conferred resistance to Cry3Aa toxicity. These data demonstrate the functional role of TmCad1 as a Cry3Aa receptor in T. molitor and reveal similarities between the mode of action of Cry toxins in Lepidoptera and Coleoptera. PMID:19416969

  12. Comparison of preliminary results from Airborne Aster Simulator (AAS) with TIMS data

    NASA Technical Reports Server (NTRS)

    Kannari, Yoshiaki; Mills, Franklin; Watanabe, Hiroshi; Ezaka, Teruya; Narita, Tatsuhiko; Chang, Sheng-Huei

    1992-01-01

    The Japanese Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER), being developed for a NASA EOS-A satellite, will have 3 VNIR, 6 SWIR, and 5 TIR (8-12 micron) bands. An Airborne ASTER Simulator (AAS) was developed for Japan Resources Observation System Organization (JAROS) by the Geophysical Environmental Research Group (GER) Corp. to research surface temperature and emission features in the MWIR/TIR, to simulate ASTER's TIR bands, and to study further possibility of MWIR/TIR bands. ASTER Simulator has 1 VNIR, 3 MWIR (3-5 microns), and 20 (currently 24) TIR bands. Data was collected over 3 sites - Cuprite, Nevada; Long Valley/Mono Lake, California; and Death Valley, California - with simultaneous ground truth measurements. Preliminary data collected by AAS for Cuprite, Nevada is presented and AAS data is compared with Thermal Infrared Multispectral Scanner (TIMS) data.

  13. tRNAHis guanylyltransferase catalyzes a 3'-5' polymerization reaction that is distinct from G-1 addition.

    PubMed

    Jackman, Jane E; Phizicky, Eric M

    2006-06-06

    Yeast tRNA(His) guanylyltransferase, Thg1, is an essential protein that adds a single guanine to the 5' end (G(-1)) of tRNA(His). This G(-1) residue is required for aminoacylation of tRNA(His) by histidyl-tRNA synthetase, both in vitro and in vivo. The guanine nucleotide addition reaction catalyzed by Thg1 extends the polynucleotide chain in the reverse (3'-5') direction of other known polymerases, albeit by one nucleotide. Here, we show that alteration of the 3' end of the Thg1 substrate tRNA(His) unleashes an unexpected reverse polymerase activity of wild-type Thg1, resulting in the 3'-5' addition of multiple nucleotides to the tRNA, with efficiency comparable to the G(-1) addition reaction. The addition of G(-1) forms a mismatched G.A base pair at the 5' end of tRNA(His), and, with monophosphorylated tRNA substrates, it is absolutely specific for tRNA(His). By contrast, reverse polymerization forms multiple G.C or C.G base pairs, and, with preactivated tRNA species, it can initiate at positions other than -1 and is not specific for tRNA(His). Thus, wild-type Thg1 catalyzes a templated polymerization reaction acting in the reverse direction of that of canonical DNA and RNA polymerases. Surprisingly, Thg1 can also readily use dNTPs for nucleotide addition. These results suggest that 3'-5' polymerization represents either an uncharacterized role for Thg1 in RNA or DNA repair or metabolism, or it may be a remnant of an earlier catalytic strategy used in nature.

  14. The growth of small corrosion fatigue cracks in alloy 2024

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Willard, Scott A.

    1993-01-01

    The corrosion fatigue crack growth characteristics of small surface and corner cracks in aluminum alloy 2024 is established. The damaging effect of salt water on the early stages of small crack growth is characterized by crack initiation at constituent particle pits, intergranular microcracking for a less than 100 micrometers, and transgranular small crack growth for a micrometer. In aqueous 1 percent NaCl and at a constant anodic potential of -700 mV(sub SCE), small cracks exhibit a factor of three increase in fatigue crack growth rates compared to laboratory air. Small cracks exhibit accelerated corrosion fatigue crack growth rates at low levels of delta-K (less than 1 MPa square root of m) below long crack delta-K (sub th). When exposed to Paris regime levels of crack tip stress intensity, small corrosion fatigue cracks exhibit growth rates similar to that observed for long cracks. Results suggest that crack closure effects influence the corrosion fatigue crack growth rates of small cracks (a less than or equal to 100 micrometers). This is evidenced by similar small and long crack growth behavior at various levels of R. Contrary to the corrosion fatigue characteristics of small cracks in high strength steels, no pronounced chemical crack length effect is observed for Al by 2024 exposed to salt water.

  15. Constitutive behavior of as-cast AA1050, AA3104, and AA5182

    NASA Astrophysics Data System (ADS)

    van Haaften, W. M.; Magnin, B.; Kool, W. H.; Katgerman, L.

    2002-07-01

    Recent thermomechanical modeling to calculate the stress field in industrially direct-chill (DC) cast-aluminum slabs has been successful, but lack of material data limits the accuracy of these calculations. Therefore, the constitutive behavior of three aluminum alloys (AA1050, AA3104, and AA5182) was determined in the as-cast condition using tensile tests at low strain rates and from room temperature to solidus temperature. The parameters of two constitutive equations, the extended Ludwik equation and a combination of the Sellars-Tegart equation with a hardening law, were determined. In order to study the effect of recovery, the constitutive behavior after prestraining at higher temperatures was also investigated. To evaluate the quantified constitutive equations, tensile tests were performed simulating the deformation and cooling history experienced by the material during casting. It is concluded that both constitutive equations perform well, but the combined hardening-Sellars-Tegart (HST) equation has temperature-independent parameters, which makes it easier to implement in a DC casting model. Further, the deformation history of the ingot should be taken into account for accurate stress calculations.

  16. Negative Affect, Relapse, and Alcoholics Anonymous (AA): Does AA Work by Reducing Anger?*

    PubMed Central

    Kelly, John F.; Stout, Robert L.; Tonigan, J. Scott; Magill, Molly; Pagano, Maria E.

    2010-01-01

    Objective: Anger and other indices of negative affect have been implicated in a stress-induced pathway to relapse. The Alcoholics Anonymous (AA) literature states that reduction of anger is critical to recovery, yet this proposed mechanism has rarely been investigated. Using lagged, controlled hierarchical linear modeling analyses, this study investigated whether AA attendance mobilized changes in anger and whether such changes explained AA-related benefit. Method: Alcohol-dependent adults (N = 1,706) receiving treatment as part of a clinical trial were assessed at intake and at 3, 6, 9, 12, and 15 months. Results: Findings revealed substantially elevated levels of anger compared with the general population (98th percentile) that decreased over 15-month follow-up but remained high (89th percentile). AA attendance was associated with better drinking outcomes, and higher levels of anger were associated with heavier drinking. However, AA attendance was unrelated to changes in anger. Conclusions: Although support was not found for anger as a mediator, there was strong convergence between AA's explicit emphasis on anger and the present findings: Anger appears to be a serious, enduring problem related to relapse and heavy alcohol consumption. Methodological factors may have contributed to the lack of association between AA and anger, but results suggest that AA attendance alone may be insufficient to alleviate the suffering and alcohol-related risks specifically associated with anger. PMID:20409438

  17. Sipuleucel-T: Prototype for development of anti-tumor vaccines.

    PubMed

    Carballido, Estrella; Fishman, Mayer

    2011-04-01

    Prostate cancer immunotherapy officially debuted with the recent FDA approval of Sipuleucel-T. The novel trend of cancer immunotherapy relies on the identification of particular tumor-associated antigens, like prostatic acid phosphatase (PAP). Sipuleucel-T consists of autologous dendritic cells activated in vitro with recombinant fusion protein PA2024, PAP-linked to granulocyte-macrophage colony-stimulating factor. Sipuleucel-T represents a prototype for the development of cancer vaccines. Preclinical and clinical data as well as landmark studies for the existing narrow chemotherapy alternatives and early immunotherapy trials will be discussed. The pivotal trial demonstrated a 4.1-month difference of median survival, but with no effect on time to progression in asymptomatic or minimally symptomatic metastatic castrate-resistant patients. Several immunologic effects were observed in the treated population, including antibody and T cell-specific activity to P2024 and PAP. With all new therapies the extent of clinical and objective benefits versus encountered limitations should be evaluated. This review highlights the events and decisions in the process of the development of Sipuleucel-T. We discuss how this successful immunotherapy outcome challenges us to use it as a starting point for variations to or try to amplify practical anticancer progress within the antitumor vaccine paradigm.

  18. 46 CFR 35.25-1 - Examination of boilers and machinery by engineer-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Examination of boilers and machinery by engineer-T/ALL... Engine Department § 35.25-1 Examination of boilers and machinery by engineer—T/ALL. It shall be the duty of an engineer when assuming charge of the boilers to examine the same forthwith and thoroughly. If...

  19. 46 CFR 35.25-1 - Examination of boilers and machinery by engineer-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Examination of boilers and machinery by engineer-T/ALL... Engine Department § 35.25-1 Examination of boilers and machinery by engineer—T/ALL. It shall be the duty of an engineer when assuming charge of the boilers to examine the same forthwith and thoroughly. If...

  20. 46 CFR 35.25-1 - Examination of boilers and machinery by engineer-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Examination of boilers and machinery by engineer-T/ALL... Engine Department § 35.25-1 Examination of boilers and machinery by engineer—T/ALL. It shall be the duty of an engineer when assuming charge of the boilers to examine the same forthwith and thoroughly. If...

  1. 46 CFR 35.25-1 - Examination of boilers and machinery by engineer-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Examination of boilers and machinery by engineer-T/ALL... Engine Department § 35.25-1 Examination of boilers and machinery by engineer—T/ALL. It shall be the duty of an engineer when assuming charge of the boilers to examine the same forthwith and thoroughly. If...

  2. Detection of NPM/MLF1 fusion in t(3;5)-positive acute myeloid leukemia and myelodysplasia.

    PubMed

    Arber, Daniel A; Chang, Karen L; Lyda, Mark H; Bedell, Victoria; Spielberger, Ricardo; Slovak, Marilyn L

    2003-08-01

    Balanced translocations are rare in myelodysplasia (MDS) and acute myeloid leukemia (AML) with multilineage dysplasia; however, the t(3;5)(q25;q35) and insertion variant occur in a subset of patients. To evaluate the possible genes involved in this translocation, we studied 6 cases with a t(3;5) by fluorescence in situ hybridization with probes directed against the nucleophosmin (NPM), EVI1, and Ribophorin genes, as well as a newly developed myeloid leukemia factor 1 (MLF1) BAC clone. The histologic spectrum of the cases was variable, ranging from refractory cytopenia with multilineage dysplasia to AML with multilineage dysplasia in the World Health Organization classification. An NPM/MLF1 fusion was identified in 5 of 6 cases, whereas the EVI1 and Ribophorin genes were not involved in any of the cases. The NPM/MLF1-positive cases were predominantly young adult males (median age, 33 years) who responded well to hematopoietic stem cell transplantation. These findings suggest that an NPM/MLF1 fusion is the primary molecular abnormality in t(3;5) MDS and AML with multilineage dysplasia, and also that cases with NPM/MLF1 may be clinically distinct from other MDS-associated disease.

  3. The cytochrome P450 2AA gene cluster in zebrafish (Danio rerio): Expression of CYP2AA1 and CYP2AA2 and response to phenobarbital-type inducers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kubota, Akira; Bainy, Afonso C.D.; Departamento de Bioquímica, CCB, Universidade Federal de Santa Catarina, Florianopolis, SC 88040-900

    2013-10-01

    The cytochrome P450 (CYP) 2 gene family is the largest and most diverse CYP gene family in vertebrates. In zebrafish, we have identified 10 genes in a new subfamily, CYP2AA, which does not show orthology to any human or other mammalian CYP genes. Here we report evolutionary and structural relationships of the 10 CYP2AA genes and expression of the first two genes, CYP2AA1 and CYP2AA2. Parsimony reconstruction of the tandem duplication pattern for the CYP2AA cluster suggests that CYP2AA1, CYP2AA2 and CYP2AA3 likely arose in the earlier duplication events and thus are most diverged in function from the other CYP2AAs.more » On the other hand, CYP2AA8 and CYP2AA9 are genes that arose in the latest duplication event, implying functional similarity between these two CYPs. A molecular model of CYP2AA1 showing the sequence conservation across the CYP2AA cluster reveals that the regions with the highest variability within the cluster map onto CYP2AA1 near the substrate access channels, suggesting differing substrate specificities. Zebrafish CYP2AA1 transcript was expressed predominantly in the intestine, while CYP2AA2 was most highly expressed in the kidney, suggesting differing roles in physiology. In the liver CYP2AA2 expression but not that of CYP2AA1, was increased by 1,4-bis [2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) and, to a lesser extent, by phenobarbital (PB). In contrast, pregnenolone 16α-carbonitrile (PCN) increased CYP2AA1 expression, but not CYP2AA2 in the liver. The results identify a CYP2 subfamily in zebrafish that includes genes apparently induced by PB-type chemicals and PXR agonists, the first concrete in vivo evidence for a PB-type response in fish. - Highlights: • A tandemly duplicated cluster of ten CYP2AA genes was described in zebrafish. • Parsimony and duplication analyses suggest pathways to CYP2AA diversity. • Homology models reveal amino acid positions possibly related to functional diversity. • The CYP2AA locus does not share

  4. Differences in clinical outcome between docetaxel and abiraterone acetate as the first-line treatment in chemo-naïve metastatic castration-resistant prostate cancer patients with or without the ineligible clinical factors of the COU-AA-302 study.

    PubMed

    Poon, Darren M C; Chan, Kuen; Lee, Siu H; Chan, Tim W; Sze, Henry; Lee, Eric K C; Lam, Daisy; Chan, Michelle F T

    2018-03-01

    This study aimed to compare the efficacy of abiraterone acetate (AA) versus docetaxel (T) as first-line treatment in chemo-naïve metastatic castration-resistant prostate cancer (mCRPC) patients with or without the ineligible factors of the COU-AA-302 study (presence of visceral metastases, symptomatic disease, and/or Eastern Cooperative Oncology Group performance status ≥ 2). The clinical records of chemo-naïve mCRPC patients who received AA in six public oncology centers or T in two of these centers between 2003 and 2014 were reviewed. The survival time was compared among four subgroups of patients: those with ineligible factors administered AA (Group Ineligible-AA) or T (Group Ineligible-T), and those without ineligible factors and administered AA (Group Eligible-AA) or T (Group Eligible-T). During the study period, we identified 115 mCRPC patients who received AA or T, among whom 29, 36, 29, and 21 patients were classified as Groups Ineligible-AA, Ineligible-T, Eligible-AA, and Eligible-T, respectively. Both Group Ineligible-AA and Group Eligible-AA had significantly longer progression-free survival (PFS) and similar overall survival (OS) as Group Ineligible-T and Group Eligible-T (Ineligible, PFS: 6.3 vs. 5.9 months, P  = 0.0234, OS: 7.8 vs. 15.7 months, P  = 0.1601; Eligible, PFS: 9.8 vs. 5.6 months, P  = 0.0437, OS: 20.5 vs. 18.2 months, P  = 0.7820). Compared to T, AA treatment resulted in longer PFS and similar OS in chemo-naïve mCRPC patients, irrespective of the presence of ineligible factors, suggesting that the initial treatment by AA may still be beneficial to those with the aforementioned ineligible factors.

  5. HLA-B*35-Restricted CD8+-T-Cell Epitope in Mycobacterium tuberculosis Rv2903c

    PubMed Central

    Klein, Michèl R.; Hammond, Abdulrahman S.; Smith, Steve M.; Jaye, Assan; Lukey, Pauline T.; McAdam, Keith P. W. J.

    2002-01-01

    Few human CD8+ T-cell epitopes in mycobacterial antigens have been described to date. Here we have identified a novel HLA-B*35-restricted CD8+ T-cell epitope in Mycobacterium tuberculosis Rv2903c based on a reverse immunogenetics approach. Peptide-specific CD8 T cells were able to kill M. tuberculosis-infected macrophages and produce gamma interferon and tumor necrosis factor alpha. PMID:11796635

  6. Longitudinal study of experimental induction of AA amyloidosis in mice seeded with homologous and heterologous AA fibrils.

    PubMed

    Muhammad, Naeem; Murakami, Tomoaki; Inoshima, Yasuo; Ishiguro, Naotaka

    2016-09-01

    To investigate pathogenesis and kinetics of experimentally induced murine AA amyloidosis seeded with homologous (murine) and heterologous (bovine) AA fibrils. Experimental AA amyloidosis was induced by administration of inflammatory stimulus and preformed AA fibrils to a total of 111 female C57/Black mice. In this longitudinal study, heterologous (bovine) as well as homologous (murine) AA fibrils were injected intraperitoneally to mice in various combinations. Re-stimulation was done at 120 or 300 days post first inoculation. To analyze the intensity of amyloid depositions in mice organs, immunohistochemical techniques and image J software were used. Assessment of cytokines level in sera was done using a Mouse Th1/Th2/Th17 Cytokine CBA Kit. Incidence and severity of AA amyloidosis were quite low in mice inoculated with heterologous bovine AA fibrils than homologous murine one. Homologous AA fibrils administration at first and second inoculation caused maximum amount of amyloid depositions and severe systemic form of amyloidosis. Increase in the level of pro-inflammatory cytokine IL-6 was observed after first inoculation, while second inoculation caused a further increase in the level of anti-inflammatory cytokine IL-10. AA amyloidosis can be induced by heterologous as well as homologous AA fibrils. Severity of AA amyloidosis induced with homologous AA fibrils is higher compared to heterologous AA fibrils.

  7. Normal range of serum highly-sensitive troponin-T in patients with chronic kidney disease stage 3-5.

    PubMed

    Chotivanawan, Thunnop; Krittayaphong, Rungroj

    2012-02-01

    Serum troponin-T concentrations are commonly increased in chronic kidney disease (CKD) without acute coronary syndrome. Highly-sensitive troponin-T the new tool that helpful for diagnosis of acute coronary syndrome, provides few data about normal value in patients with chronic kidney disease. The authors studied 89 patients with CKD stage 3-5: 40 had CKD stage 3, 26 had CKD stage 4 and 23 had CKD stage 5. Serum samples were collected for the analysis of highly-sensitive troponin-T levels. The values of highly-sensitive troponin-T of the total group and each CKD stage were presented. The level of highly-sensitive troponin-T in patients with CKD stage 3-5 was 0.044 +/- 0.076 ng/ml. For CKD stages 3, 4 and 5 levels were 0.015 +/- 0.016, 0.043 +/- 0.056, 0.098 +/- 0.121 ng/ml, respectively. 95th percentile of the total group was 0.139 ng/ml. 95th percentile for stage 3, 4 and 5 were 0.052, 0.136, 0.297 ng/ml, respectively. 95th percentile for highly-sensitive troponin-T of patients with CKD stage 3-5 was 0.139 ng/ml. This number may be considered as the cut-off value for diagnosis of acute myocardial infarction.

  8. Low-Temperature Friction-Stir Welding of 2024 Aluminum

    NASA Technical Reports Server (NTRS)

    Benavides, S.; Li, Y.; Murr, L. E.; Brown, D.; McClure, J. C.

    1998-01-01

    Solid state friction-stir welding (FSW) has been demonstrated to involve dynamic recrystallization producing ultra-fine, equiaxed grain structures to facilitate superplastic deformation as the welding or joining mechanism. However, the average residual, equiaxed, grain size in the weld zone has ranged from roughly 0.5 micron to slightly more than 10 micron, and the larger weld zone grain sizes have been characterized as residual or static grain growth as a consequence of the temperatures in the weld zone (where center-line temperatures in the FSW of 6061 Al have been shown to be as high as 480C or -0.8 T(sub M) where T(sub M) is the absolute melting temperature)). In addition, the average residual weld zone grain size has been observed to increase near the top of the weld, and to decrease with distance on either side of the weld-zone centerline, an d this corresponds roughly to temperature variations within the weld zone. The residual grain size also generally decreases with decreasing FSW tool rotation speed. These observations are consistent with the general rules for recrystallization where the recrystallized grain size decreases with increasing strain (or deformation) at constant strain rate, or with increasing strain-rate, or with increasing strain rate at constant strain; especially at lower ambient temperatures, (or annealing temperatures). Since the recrystallization temperature also decreases with increasing strain rate, the FSW process is somewhat complicated because the ambient temperature, the frictional heating fraction, and the adiabatic heating fraction )proportional to the product of strain and strain-rate) will all influence both the recrystallization and growth within the FSW zone. Significantly reducing the ambient temperature of the base metal or work pieces to be welded would be expected to reduce the residual weld-zone grain size. The practical consequences of this temperature reduction would be the achievement of low temperature welding. This

  9. Simultaneous quantification of T4, T3, rT3, 3,5-T2 and 3,3'-T2 in larval zebrafish (Danio rerio) as a model to study exposure to polychlorinated biphenyls.

    PubMed

    Chen, Xiaopeng; Walter, Kyla M; Miller, Galen W; Lein, Pamela J; Puschner, Birgit

    2018-06-01

    Environmental toxicants that interfere with thyroid hormone (TH) signaling can impact growth and development in animals and humans. Zebrafish represent a model to study chemically induced TH disruption, prompting the need for sensitive detection of THs. Simultaneous quantification of 3,3',5-triiodo-l-thyronine (T3), thyroxine (T4), 3,3',5'-triiodo-l-thyronine (rT3), 3,5-diiodo-l-thyronine (3,5-T2) and 3,3'-diiodo-l-thyronine (3,3'-T2) in zebrafish larvae was achieved by ultra-performance liquid chromatography-tandem mass spectrometry in positive ion mode. Solid-phase extraction with SampliQ cartridges and derivatization with 3 m hydrochloric acid in n-butanol reduced matrix effects. Derivatized compounds were separated on an Acquity UPLC BEH C 18 column with mobile phases consisting of 0.1% acetic acid in deionized water and 0.1% acetic acid in methanol. The limits of detection ranged from 0.5 to 0.6 pg injected on column. The method was validated by evaluating recovery (77.1-117.2%), accuracy (87.3-123.9%) and precision (0.5-12.4%) using diluted homogenized zebrafish embryos spiked with all target compounds. This method was then applied to zebrafish larvae collected after 114 h of exposure to polychlorinated biphenyls (PCBs), including PCB 28, PCB 66 and PCB 95, or the technical mixture Aroclor 1254. Exposure to PCB 28 and PCB 95 increased the T4:T3 ratio and decreased the T3:rT3 ratio, demonstrating that this method can effectively detect PCB-induced alterations in THs. Copyright © 2018 John Wiley & Sons, Ltd.

  10. Rationally evolving tRNAPyl for efficient incorporation of noncanonical amino acids

    PubMed Central

    Fan, Chenguang; Xiong, Hai; Reynolds, Noah M.; Söll, Dieter

    2015-01-01

    Genetic encoding of noncanonical amino acids (ncAAs) into proteins is a powerful approach to study protein functions. Pyrrolysyl-tRNA synthetase (PylRS), a polyspecific aminoacyl-tRNA synthetase in wide use, has facilitated incorporation of a large number of different ncAAs into proteins to date. To make this process more efficient, we rationally evolved tRNAPyl to create tRNAPyl-opt with six nucleotide changes. This improved tRNA was tested as substrate for wild-type PylRS as well as three characterized PylRS variants (Nϵ-acetyllysyl-tRNA synthetase [AcKRS], 3-iodo-phenylalanyl-tRNA synthetase [IFRS], a broad specific PylRS variant [PylRS-AA]) to incorporate ncAAs at UAG codons in super-folder green fluorescence protein (sfGFP). tRNAPyl-opt facilitated a 5-fold increase in AcK incorporation into two positions of sfGFP simultaneously. In addition, AcK incorporation into two target proteins (Escherichia coli malate dehydrogenase and human histone H3) caused homogenous acetylation at multiple lysine residues in high yield. Using tRNAPyl-opt with PylRS and various PylRS variants facilitated efficient incorporation of six other ncAAs into sfGFP. Kinetic analyses revealed that the mutations in tRNAPyl-opt had no significant effect on the catalytic efficiency and substrate binding of PylRS enzymes. Thus tRNAPyl-opt should be an excellent replacement of wild-type tRNAPyl for future ncAA incorporation by PylRS enzymes. PMID:26250114

  11. Characterization of the radical-scavenging reaction of 2-O-substituted ascorbic acid derivatives, AA-2G, AA-2P, and AA-2S: a kinetic and stoichiometric study.

    PubMed

    Takebayashi, Jun; Tai, Akihiro; Gohda, Eiichi; Yamamoto, Itaru

    2006-04-01

    The aim of this study was to characterize the antioxidant activity of three ascorbic acid (AA) derivatives O-substituted at the C-2 position of AA: ascorbic acid 2-glucoside (AA-2G), ascorbic acid 2-phosphate (AA-2P), and ascorbic acid 2-sulfate (AA-2S). The radical-scavenging activities of these AA derivatives and some common low molecular-weight antioxidants such as uric acid or glutathione against 1,1-diphenyl-picrylhydrazyl (DPPH) radical, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+), or galvinoxyl radical were kinetically and stoichiometrically evaluated under pH-controlled conditions. Those AA derivatives slowly and continuously reacted with DPPH radical and ABTS+, but not with galvinoxyl radical. They effectively reacted with DPPH radical under acidic conditions and with ABTS+ under neutral conditions. In contrast, AA immediately quenched all species of radicals tested at all pH values investigated. The reactivity of Trolox, a water-soluble vitamin E analogue, was comparable to that of AA in terms of kinetics and stoichiometrics. Uric acid and glutathione exhibited long-lasting radical-scavenging activity against these radicals under certain pH conditions. The radical-scavenging profiles of AA derivatives were closer to those of uric acid and glutathione rather than to that of AA. The number of radicals scavenged by one molecule of AA derivatives, uric acid, or glutathione was equal to or greater than that by AA or Trolox under the appropriate conditions. These data suggest the potential usage of AA derivatives as radical scavengers.

  12. Methionine Regulates mTORC1 via the T1R1/T1R3-PLCβ-Ca2+-ERK1/2 Signal Transduction Process in C2C12 Cells.

    PubMed

    Zhou, Yuanfei; Ren, Jiao; Song, Tongxing; Peng, Jian; Wei, Hongkui

    2016-10-11

    The mammalian target of rapamycin complex 1 (mTORC1) integrates amino acid (AA) availability to support protein synthesis and cell growth. Taste receptor type 1 member (T1R) is a G protein-coupled receptor that functions as a direct sensor of extracellular AA availability to regulate mTORC1 through Ca 2+ stimulation and extracellular signal-regulated kinases 1 and 2 (ERK1/2) activation. However, the roles of specific AAs in T1R1/T1R3-regulated mTORC1 are poorly defined. In this study, T1R1 and T1R3 subunits were expressed in C2C12 myotubes, and l-AA sensing was accomplished by T1R1/T1R3 to activate mTORC1. In response to l-AAs, such as serine (Ser), arginine (Arg), threonine (Thr), alanine (Ala), methionine (Met), glutamine (Gln), and glycine (Gly), Met induced mTORC1 activation and promoted protein synthesis. Met also regulated mTORC1 via T1R1/T1R3-PLCβ-Ca 2+ -ERK1/2 signal transduction. Results revealed a new role for Met-regulated mTORC1 via an AA receptor. Further studies should be performed to determine the role of T1R1/T1R3 in mediating extracellular AA to regulate mTOR signaling and to reveal its mechanism.

  13. Nephrotic syndrome and AA amyloidosis revealing adult-onset cryopyrin-associated periodic syndrome.

    PubMed

    Enríquez, R; Sirvent, A E; Padilla, S; Noguera-Pons, R; Andrada, E; Ardoy, F; Millán, I; Amorós, F

    2013-01-01

    Cryopyrin-associated periodic syndrome (CAPS) is due to gain-of-function mutations in the cryopyrin gene, which determines an overactive inflammatory response. AA amyloidosis is a complication of this syndrome. A 53-year-old man was referred to us because of lower limb edema. Past history: at the age of 20, he complained of arthralgia/arthritis and bilateral hypoacusis. At the age of 35, he presented posterior uveitis, several episodes of conjunctivitis, and progressive loss of visual acuity. Laboratory tests disclosed nephrotic syndrome, and renal biopsy showed AA amyloidosis. He was given anakinra with improvement of arthritis. A genetic study revealed the p.D303N mutation in the cryopyrin gene, and he was diagnosed as having AA amyloidosis due to CAPS. Twenty-one months after starting anakinra, the arthritis has disappeared, although nephrotic-range proteinuria persisted. It is important to be aware of cryopyrin-associated periodic syndrome because it can cause irreversible complications, and there is effective therapy.

  14. Detection of AA76, a Common Form of Amyloid A Protein, as a Way of Diagnosing AA Amyloidosis.

    PubMed

    Sato, Junji; Okuda, Yasuaki; Kuroda, Takeshi; Yamada, Toshiyuki

    2016-01-01

    Reactive amyloid deposits consist of amyloid A (AA) proteins, the degradation products of serum amyloid A (SAA). Since the most common species of AA is the amino terminal portion produced by cleavage between residues 76 and 77 of SAA (AA76), the presence of AA76 in tissues could be a consequence of AA amyloid deposition. This study assessed the diagnostic significance of the detection of AA76 for AA amyloidosis using two different approaches. Biopsy specimens (n=130 from 54 subjects) from gastroduodenal mucosa or abdominal fat (n=9 from 9 subjects) of patients who had already been diagnosed with or were suspected of having AA amyloidosis were used. Fixed mucosal sections were subjected to immunohistochemistry using a newly developed antibody recognizing the carboxyl terminal end of AA76 (anti-AA76). The non-fixed materials from gastroduodenal mucosa or abdominal fat were subjected to immunoblotting for detection of the size of AA76. Among the gastroduodenal specimens (n=115) from already diagnosed patients, the positive rates of Congo red staining, immunohistochemistry using anti-AA76, and immunoblotting were 68.4%, 73.0%, and 92.2%, respectively. The anti-AA76 did not stain the supposed SAA in the blood or leakage, which was stained by anti-SAA antibody. AA76 was not detected either by immunohistochemistry or by immunoblot in the materials from patients in whom AA amyloidosis had been ruled out. In the abdominal fat, the immunoblot detected AA76 in 8 materials from 8 already diagnosed patients and did not in 1 patient whose gastroduodenal mucosa was negative. In conclusion, the detection of AA76 may alter the ability to diagnose AA amyloidosis. In immunohistochemistry for fixed specimens, the new anti-AA76 antibody can improve the specificity. Immunoblot for non-fixed materials, which can considerably improve the sensitivity, should be beneficial for small materials like abdominal fat. © 2016 by the Association of Clinical Scientists, Inc.

  15. Plasmodium falciparum mitochondria import tRNAs along with an active phenylalanyl-tRNA synthetase.

    PubMed

    Sharma, Arvind; Sharma, Amit

    2015-02-01

    The Plasmodium falciparum protein translation enzymes aminoacyl-tRNA synthetases (aaRSs) are an emergent family of drug targets. The aaRS ensemble catalyses transfer of amino acids to cognate tRNAs, thus providing charged tRNAs for ribosomal consumption. P. falciparum proteome expression relies on a total of 36 aaRSs for the three translationally independent compartments of cytoplasm, apicoplast and mitochondria. In the present study, we show that, of this set of 36, a single genomic copy of mitochondrial phenylalanyl-tRNA synthetase (mFRS) is targeted to the parasite mitochondria, and that the mFRS gene is exclusive to malaria parasites within the apicomplexan phyla. Our protein cellular localization studies based on immunofluorescence data show that, along with mFRS, P. falciparum harbours two more phenylalanyl-tRNA synthetase (FRS) assemblies that are localized to its apicoplast and cytoplasm. The 'extra' mFRS is found in mitochondria of all asexual blood stage parasites and is competent in aminoacylation. We show further that the parasite mitochondria import tRNAs from the cytoplasmic tRNA pool. Hence drug targeting of FRSs presents a unique opportunity to potentially stall protein production in all three parasite translational compartments.

  16. PDGF-AA-induced filamentous mitochondria benefit dermal papilla cells in cellular migration.

    PubMed

    Mifude, C; Kaseda, K

    2015-06-01

    Human dermal papilla cells (HDPCs) play essential roles in hair follicular morphogenesis and postnatal hair growth cycles. Previous reports demonstrated that platelet-derived growth factor-AA (PDGF-AA) enhanced the formation of dermal condensates in hair follicular development. Additionally, PDGF-AA induces/maintains the anagen phase of the hair cycle. It is likely that mitochondrial morphology and functions are tightly coupled with maintenance of these energy-demanding activities. However, little is known about the mitochondrial regulation in HDPCs. Thus, we investigated the PDGF-involved mitochondrial regulation in HDPCs. The mitochondrial morphologies of HDPCs were examined in the presence or absence of PDGF-AA under a fluorescent microscope. ATP production and cellular motility were investigated. The relationship between mitochondrial morphology and the cellular functions was discussed. We observed that primary HDPCs contained mitochondria with filamentous and/or rounded morphologies. Both types of mitochondria showed similar membrane potentials. Interestingly, in the presence of PDGF-AA, but not PDGF-BB, the balance between the two morphologies shifted towards the filamentous form. Concomitantly, both mitochondrial enzymatic activity and total cellular ATP level were augmented by PDGF-AA. These two parameters were closely correlated, suggesting the mitochondrial involvement in the PDGF-augmented ATP production. Moreover, PDGF-AA accelerated the migration of HDPCs in a gap-filling assay, but did not change the rate of cellular proliferation. Notably, filamentous mitochondria dominated migrating HDPCs. PDGF-AA benefits HDPCs in the process of migration, by increasing the number of filamentous mitochondria. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  17. Cytotoxic 20,24-epoxywithanolides from Physalis angulata.

    PubMed

    Maldonado, Emma; Hurtado, Norma E; Pérez-Castorena, Ana L; Martínez, Mahinda

    2015-12-01

    A new withanolide, physangulide B (1), was isolated from calyxes of Physalis angulata. This compound was also present in the aerial parts along with the known physangulide (4), which was isolated as the acetonide 3, and 24,25-epoxywithanolide D (6). Structures of these compounds were determined by analysis of their spectroscopic data, which indicated the presence of a 20,24-epoxy group in both physangulides. The structures of compounds 1 and 6 were confirmed by X-ray analysis of their corresponding acetyl derivatives 2 and 7. The structure of physangulide was originally described as the 22S withanolide 5, now its structure and configuration are revised to 4. Evaluation of the cytotoxic activity of compounds 1-3 against two human cancer cell lines indicated a potent activity of compound 1 and its derivative 2. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Microstructure and mechanical properties of 2024-T3 and 7075-T6 aluminum alloys and austenitic stainless steel 304 after being exposed to hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Sofyan, Nofrijon Bin Imam

    The effect of hydrogen peroxide used as a decontaminant agent on selected aircraft metallic materials has been investigated. The work is divided into three sections; bacterial attachment behavior onto an austenitic stainless steel 304 surface; effect of decontamination process on the microstructure and mechanical properties of aircraft metallic structural materials of two aluminum alloys, i.e. 2024-T3 and 7075-T6, and an austenitic stainless steel 304 as used in galley and lavatory surfaces; and copper dissolution rate into hydrogen peroxide. With respect to bacterial attachment, the results show that surface roughness plays a role in the attachment of bacteria onto metallic surfaces at certain extent. However, when the contact angle of the liquid on a surface increased to a certain degree, detachment of bacteria on that surface became more difficult. In its relation to the decontamination process, the results show that a corrosion site, especially on the austenitic stainless steel 304 weld and its surrounding HAZ area, needs more attention because it could become a source or a harborage of bio-contaminant agent after either incidental or intentional bio-contaminant delivery. On the effect of the decontamination process on the microstructure and mechanical properties of aircraft metallic structural materials, the results show that microstructural effects are both relatively small in magnitude and confined to a region immediately adjacent to the exposed surface. No systematic effect is found on the tensile properties of the three alloys under the conditions examined. The results of this investigation are promising with respect to the application of vapor phase hydrogen peroxide as a decontaminant agent to civilian aircraft, in that even under the most severe circumstances that could occur; only very limited damage was observed. The results from the dissolution of copper by concentrated liquid hydrogen peroxide showed that the rate of copper dissolution increased for

  19. Alcoholics Anonymous-Related Benefit for Urban Native Americans: Does Urban Native American Gender Moderate AA Engagement and Outcomes?

    PubMed

    Muñoz, Rosa E; Tonigan, J Scott

    2017-01-01

    Alcoholics Anonymous (AA) is one of the most commonly accessed resources for individuals seeking to reduce their drinking. How urban Native Americans fare in AA is only beginning to be investigated in spite of circumstantial evidence suggesting that a majority of treatment-seeking urban Native Americans will receive 12-step treatment. Even less is known about Native American gender differences with regard to AA-related benefit. The current study addressed this gap by investigating urban Native American gender differences in AA attendance rates and outcomes. To this end, as part of two larger NIH-funded studies we recruited 63 Native American men and women and followed them for 9 months in this naturalistic study (n= 35 males, n = 28 females). Urban Native Americans significantly reduced their drinking over the study period, and AA attendance explained, in part, increased abstinence of study participants. No significant differences in AA attendance and drinking outcomes were observed between Native American men and women; however, descriptively men reported greater reductions in hazardous drinking relative to women. Clinical implications and future directions are discussed.

  20. A method for predicting the fatigue life of pre-corroded 2024-T3 aluminum from breaking load tests

    NASA Astrophysics Data System (ADS)

    Gruenberg, Karl Martin

    Characterization of material properties is necessary for design purposes and has been a topic of research for many years. Over the last several decades, much progress has been made in identifying metrics to describe fracture mechanics properties and developing procedures to measure the appropriate values. However, in the context of design, there has not been as much success in quantifying the susceptibility of a material to corrosion damage and its subsequent impact on material behavior in the framework of fracture mechanics. A natural next step in understanding the effects of corrosion damage was to develop a link between standard material test procedures and fatigue life in the presence of corrosion. Simply stated, the goal of this investigation was to formulate a cheaper and quicker method for assessing the consequences of corrosion on remaining fatigue life. For this study, breaking load specimens and fatigue specimens of a single nominal gage (0.063″) of aluminum alloy 2024-T3 were exposed to three levels of corrosion. The breaking load specimens were taken from three different material lots, and the fatigue tests were carried out at three stress levels. All failed specimens, both breaking load and fatigue specimens, were examined to characterize the damage state(s) and failure mechanism(s). Correlations between breaking load results and fatigue life results in the presence of corrosion damage were developed using a fracture mechanics foundation and the observed mechanisms of failure. Where breaking load tests showed a decrease in strength due to increased corrosion exposure, the corresponding set of fatigue tests showed a decrease in life. And where breaking load tests from different specimen orientations exhibited similar levels of strength, the corresponding set of fatigue specimens showed similar lives. The spread from shortest to longest fatigue lives among the different corrosion conditions decreased at the higher stress levels. Life predictions based

  1. Post-therapeutic recovery of serum interleukin-35 level might predict positive response to immunosuppressive therapy in pediatric aplastic anemia.

    PubMed

    Huang, Zhen; Tong, Hongfei; Li, Yuan; Zhou, Haixia; Qian, Jiangchao; Wang, Juxiang; Ruan, Jichen

    2017-08-01

    The predictive value of interleukin-35 (IL-35) on efficacy of immunosuppressive therapy (IST) in aplastic anemia (AA) has not been well investigated. The aim of the study was to evaluate the association between serum IL-35 level and response to IST in pediatric AA. A total of 154 children with AA and 154 controls were included between January 2012 and December 2013. Blood and bone marrow fluid specimens were collected. Serum level of IL-35 was determined by enzyme-linked immunosorbent assay. Patients were treated with IST, and response to therapy was evaluated during 180-day follow-up period after starting therapy. Serum levels of IL-35 at admission decreased significantly in patients compared with that in controls (10.9 ± 5.5 pg ml -1 and 45.3 ± 8.8 pg ml -1 , p < 0.001). After starting IST, serum levels of IL-35 in patients recovered 30.7 ± 9.7 pg ml -1 in the first 28 days (p < 0.001). During the follow-up period, increased range of serum IL-35 level ≥30.7 pg ml -1 in the first 28 days was associated with effective response to therapy (odds ratio 7.97, 95% confidence interval 3.82-16.79). In addition, Fas/FasL protein expression in bone marrow mononuclear cells dropped significantly in the same group of patients in the first 28 days (p < 0.05). The study revealed that post-therapeutic recovery of circulating IL-35 concentration might be an independent predictor for effective response to IST in pediatric AA. Moreover, apoptosis might be involved in such a forecasting process.

  2. Identification of Bacillus thuringiensis Cry3Aa toxin domain II loop 1 as the binding site of Tenebrio molitor cadherin repeat CR12.

    PubMed

    Zúñiga-Navarrete, Fernando; Gómez, Isabel; Peña, Guadalupe; Amaro, Itzel; Ortíz, Ernesto; Becerril, Baltazar; Ibarra, Jorge E; Bravo, Alejandra; Soberón, Mario

    2015-04-01

    Bacillus thuringiensis Cry toxins exert their toxic effect by specific recognition of larval midgut proteins leading to oligomerization of the toxin, membrane insertion and pore formation. The exposed domain II loop regions of Cry toxins have been shown to be involved in receptor binding. Insect cadherins have shown to be functionally involved in toxin binding facilitating toxin oligomerization. Here, we isolated a VHH (VHHA5) antibody by phage display that binds Cry3Aa loop 1 and competed with the binding of Cry3Aa to Tenebrio molitor brush border membranes. VHHA5 also competed with the binding of Cry3Aa to a cadherin fragment (CR12) that was previously shown to be involved in binding and toxicity of Cry3Aa, indicating that Cry3Aa binds CR12 through domain II loop 1. Moreover, we show that a loop 1 mutant, previously characterized to have increased toxicity to T. molitor, displayed a correlative enhanced binding affinity to T. molitor CR12 and to VHHA5. These results show that Cry3Aa domain II loop 1 is a binding site of CR12 T. molitor cadherin. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. High speed machinability of the aerospace alloy AA7075 T6 under different cooling conditions

    NASA Astrophysics Data System (ADS)

    Imbrogno, Stano; Rinaldi, Sergio; Suarez, Asier Gurruchaga; Arrazola, Pedro J.; Umbrello, Domenico

    2018-05-01

    This paper describes the results of an experimental investigation aimed to st udy the machinability of AA7075 T6 (160 HV) for aerospace industry at high cutting speeds. The paper investigates the effects of different lubri-cooling strategies (cryogenic, M QL and dry) during high speed turning process on cutting forces, tool wear, chip morphology and cutting temperatures. The cutting speeds selected were 1000m/min, 1250m/min and 1500 m/min, while the feed rate values used were 0.1mm/rev and 0.3 mm/rev. The results of cryogenic and M QL application is compared with dry application. It was found that the cryogenic and M QL lubri-cooling techniques could represent a functional alternative to the common dry cutting application in order to implement a more effect ive high speed turning process. Higher cuttingparameters would be able to increase the productivity and reduce the production costs. The effects of the cutting parameters and on the variables object of study were investigated and the role of the different lubri-cooling conditions was assessed.

  4. The trajectory and atmospheric impact of asteroid 2014 AA

    NASA Astrophysics Data System (ADS)

    Farnocchia, Davide; Chesley, Steven R.; Brown, Peter G.; Chodas, Paul W.

    2016-08-01

    Near-Earth asteroid 2014 AA entered the Earth's atmosphere on 2014 January 2, only 21 h after being discovered by the Catalina Sky Survey. In this paper we compute the trajectory of 2014 AA by combining the available optical astrometry, seven ground-based observations over 69 min, and the International Monitoring System detection of the atmospheric impact infrasonic airwaves in a least-squares orbit estimation filter. The combination of these two sources of observations results in a tremendous improvement in the orbit uncertainties. The impact time is 3:05 UT with a 1σ uncertainty of 6 min, while the impact location corresponds to a west longitude of 44.2° and a latitude of 13.1° with a 1σ uncertainty of 140 km. The minimum impact energy estimated from the infrasound data and the impact velocity result in an estimated minimum mass of 22.6 t. By propagating the trajectory of 2014 AA backwards we find that the only window for finding precovery observations is for the three days before its discovery.

  5. Advantages of Residual Stresses in Dynamically Riveted Joints.

    DTIC Science & Technology

    1978-02-01

    strain distribution around a rivet hole, and describes an experimental method for measuring the radial velocity of an expanding rivet. The advantages of... benefits of compressive residual stresses in riveted joints, fatigue specimens made of 2024-T81 aluminum were used. The specimens were tested at constant...concentration of in-service tensile stresses near the hole surfaze. Substan;Aal and significant benefits in design life and structural weight can be

  6. [Risk control of traditional Chinese medicines containing aristolochis acids (AAs) based on influencing factors of content of AAs].

    PubMed

    Tian, Jing-Zhuo; Liang, Ai-Hua; Liu, Jing; Zhang, Bo-Li

    2017-12-01

    Aristolochic acids (AAs) widely exist in such plants as Aristolochia and Asarum. The renal toxicity of AAs as well as its carcinogenicity to urinary system have been widely known. In 2003 and 2004, China prohibited the use of Aristolochiae Radix, Aristolochiae Manshuriensis Caulis and Aristolochiae Fangchi Radix, and required administering other AAs-containing medicines in accordance with the regulations for prescription drugs. In this paper, we retrieved literatures on the content determination of AAs in recent 10 years in China. It suggested that the AAs content is lower in Asarum herb, especially in its roots and rhizomes, and most of which do not show detectable amount of AA-I. Some of traditional Chinese medicines show fairly small amount of detectable AA-I. The AAs content in Aristolochia herb (including Fructus Aristolochiae, kaempfer dutchmanspipe root) is relatively high; however, there are fewer literatures for studying the content determination of AAs in Chinese patent medicines. There were many factors affecting AAs content, including the parts used, origins, processing methods, extraction process. It suggested that we should pay attention to the toxicity of Chinese medicines containing AAs and use these decoction pieces and traditional Chinese medicines cautiously. In addition, basic studies for the origins, processing methods and extraction process of Chinese patent medicines containing AAs, as well as supervision and detection of AAs content in traditional Chinese medicinal materials, decoction pieces and Chinese patent medicines shall be strengthened for reducing medication risk and guaranteeing clinical medication safety. Copyright© by the Chinese Pharmaceutical Association.

  7. Rationally evolving tRNAPyl for efficient incorporation of noncanonical amino acids.

    PubMed

    Fan, Chenguang; Xiong, Hai; Reynolds, Noah M; Söll, Dieter

    2015-12-15

    Genetic encoding of noncanonical amino acids (ncAAs) into proteins is a powerful approach to study protein functions. Pyrrolysyl-tRNA synthetase (PylRS), a polyspecific aminoacyl-tRNA synthetase in wide use, has facilitated incorporation of a large number of different ncAAs into proteins to date. To make this process more efficient, we rationally evolved tRNA(Pyl) to create tRNA(Pyl-opt) with six nucleotide changes. This improved tRNA was tested as substrate for wild-type PylRS as well as three characterized PylRS variants (N(ϵ)-acetyllysyl-tRNA synthetase [AcKRS], 3-iodo-phenylalanyl-tRNA synthetase [IFRS], a broad specific PylRS variant [PylRS-AA]) to incorporate ncAAs at UAG codons in super-folder green fluorescence protein (sfGFP). tRNA(Pyl-opt) facilitated a 5-fold increase in AcK incorporation into two positions of sfGFP simultaneously. In addition, AcK incorporation into two target proteins (Escherichia coli malate dehydrogenase and human histone H3) caused homogenous acetylation at multiple lysine residues in high yield. Using tRNA(Pyl-opt) with PylRS and various PylRS variants facilitated efficient incorporation of six other ncAAs into sfGFP. Kinetic analyses revealed that the mutations in tRNA(Pyl-opt) had no significant effect on the catalytic efficiency and substrate binding of PylRS enzymes. Thus tRNA(Pyl-opt) should be an excellent replacement of wild-type tRNA(Pyl) for future ncAA incorporation by PylRS enzymes. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  8. Polyspecific pyrrolysyl-tRNA synthetases from directed evolution.

    PubMed

    Guo, Li-Tao; Wang, Yane-Shih; Nakamura, Akiyoshi; Eiler, Daniel; Kavran, Jennifer M; Wong, Margaret; Kiessling, Laura L; Steitz, Thomas A; O'Donoghue, Patrick; Söll, Dieter

    2014-11-25

    Pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNA(Pyl) have emerged as ideal translation components for genetic code innovation. Variants of the enzyme facilitate the incorporation >100 noncanonical amino acids (ncAAs) into proteins. PylRS variants were previously selected to acylate N(ε)-acetyl-Lys (AcK) onto tRNA(Pyl). Here, we examine an N(ε)-acetyl-lysyl-tRNA synthetase (AcKRS), which is polyspecific (i.e., active with a broad range of ncAAs) and 30-fold more efficient with Phe derivatives than it is with AcK. Structural and biochemical data reveal the molecular basis of polyspecificity in AcKRS and in a PylRS variant [iodo-phenylalanyl-tRNA synthetase (IFRS)] that displays both enhanced activity and substrate promiscuity over a chemical library of 313 ncAAs. IFRS, a product of directed evolution, has distinct binding modes for different ncAAs. These data indicate that in vivo selections do not produce optimally specific tRNA synthetases and suggest that translation fidelity will become an increasingly dominant factor in expanding the genetic code far beyond 20 amino acids.

  9. Polyspecific pyrrolysyl-tRNA synthetases from directed evolution

    PubMed Central

    Guo, Li-Tao; Wang, Yane-Shih; Nakamura, Akiyoshi; Eiler, Daniel; Kavran, Jennifer M.; Wong, Margaret; Kiessling, Laura L.; Steitz, Thomas A.; O’Donoghue, Patrick; Söll, Dieter

    2014-01-01

    Pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNAPyl have emerged as ideal translation components for genetic code innovation. Variants of the enzyme facilitate the incorporation >100 noncanonical amino acids (ncAAs) into proteins. PylRS variants were previously selected to acylate Nε-acetyl-Lys (AcK) onto tRNAPyl. Here, we examine an Nε-acetyl-lysyl-tRNA synthetase (AcKRS), which is polyspecific (i.e., active with a broad range of ncAAs) and 30-fold more efficient with Phe derivatives than it is with AcK. Structural and biochemical data reveal the molecular basis of polyspecificity in AcKRS and in a PylRS variant [iodo-phenylalanyl-tRNA synthetase (IFRS)] that displays both enhanced activity and substrate promiscuity over a chemical library of 313 ncAAs. IFRS, a product of directed evolution, has distinct binding modes for different ncAAs. These data indicate that in vivo selections do not produce optimally specific tRNA synthetases and suggest that translation fidelity will become an increasingly dominant factor in expanding the genetic code far beyond 20 amino acids. PMID:25385624

  10. The NBS: Processing/Microstructure/Property Relationships in 2024 Aluminum Alloy Plates

    NASA Technical Reports Server (NTRS)

    Ives, L. K.; Swartzendruber, W. J.; Boettinger, W. J.; Rosen, M.; Ridder, S. D.

    1983-01-01

    As received plates of 2024 aluminum alloy were examined. Topics covered include: solidification segregation studies; microsegregation and macrosegregation in laboratory and commercially cast ingots; C-curves and nondestructive evaluation; time-temperature precipitation diagrams and the relationships between mechanical properties and NDE measurements; transmission electron microscopy studies; the relationship between microstructure and properties; ultrasonic characterization; eddy-current conductivity characterization; the study of aging process by means of dynamic eddy current measurements; and Heat flow-property predictions, property degradations due to improve quench from the solution heat treatment temperature.

  11. Investigation of Hot Cracking Behavior in Transverse Mechanically Arc Oscillated Autogenous AA2014 T6 TIG Welds

    NASA Astrophysics Data System (ADS)

    Biradar, N. S.; Raman, R.

    2012-09-01

    Hot cracking studies on autogenous AA2014 T6 TIG welds were carried out. Significant cracking was observed during linear and circular welding test (CWT) on 4-mm-thick plates. Weld metal grain structure and amount of liquid distribution during the terminal stages of solidification were the key cause for hot cracking in aluminum welds. Square-wave AC TIG welding with transverse mechanical arc oscillation (TMAO) was employed to study the cracking behavior during linear and CWT. TMAO welds with amplitude = 0.9 mm and frequency = 0.5 Hz showed significant reduction in cracking tendency. The increase in cracking resistance in the arc-oscillated weld was attributed to grain refinement and improved weld bead morphology, which improved the weld metal ductility and uniformity, respectively, of residual tensile stresses that developed during welding. The obtained results were comparable to those of reported favorable results of electromagnetic arc oscillation.

  12. Methodology for Evaluation of Fatigue Crack-Growth Resistance of Aluminum Alloys under Spectrum Loading.

    DTIC Science & Technology

    1982-04-01

    fatigue life , except for the 2024 - T351 alloy which had a significantly longer spectrum fatigue life than the other alloys and 2) for...OF FATIGUE CRACK GROWTH OF ALUMINUM ALLOYS UNDER SPECTRUM LOADING MATERIALS PRESENT EFFORT FUTURE EFFORT 2024 - T351 2020-T651 2024 -T851 TMT2020-T6X51...the same spectrum fatigue life . The 2024 - T351 alloy had a significantly longer spectrum

  13. Effect of Temper Condition on the Corrosion and Fatigue Performance of AA2219 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Ghosh, Rahul; Venugopal, A.; Rao, G. Sudarshan; Ramesh Narayanan, P.; Pant, Bhanu; Cherian, Roy M.

    2018-02-01

    The effect of temper condition and corrosion on the fatigue behavior of alloy AA2219 has been investigated in different temper conditions (T87 and T851). Corrosion testing was performed by exposing the tensile specimens to 3.5% NaCl solution for different time periods, and the corrosion damage was quantified using a 3D profilometer. The exposure-tested specimens were subjected for fatigue testing at different stress levels, and the reduction in fatigue life was measured along with detailed fracture morphology variations. The results indicated that the alloy in both tempers suffers localized corrosion damage and the measured corrosion depth was 120 and 1200 µm, respectively, for T87 and T851 conditions. The loss in fatigue strength was found to be high for T851 (67%) when compared to that of T87 temper condition (58%) for a pre-corrosion time of 15 days. In both cases, fatigue crack initiation is associated with corrosion pits, which act as stress raisers. However, the crack propagation was predominantly transgranular for T87 and a mixed transgranular and intergranular fracture in the case of T851 temper condition. This was shown to be due to the heterogeneous microstructure due to the thermomechanical working and the delay in quench time imposed on the alloy forging in T851 temper condition. The findings in this paper present useful information for the selection of appropriate heat treatment condition to facilitate control of the corrosion behavior which is of great significance for their fatigue performance.

  14. Characterization of amyloid in equine recurrent uveitis as AA amyloid.

    PubMed

    Ostevik, L; de Souza, G A; Wien, T N; Gunnes, G; Sørby, R

    2014-01-01

    Two horses with chronic uveitis and histological lesions consistent with equine recurrent uveitis (ERU) were examined. Microscopical findings in the ciliary body included deposits of amyloid lining the non-pigmented epithelium, intracytoplasmic, rod-shaped, eosinophilic inclusions and intraepithelial infiltration of T lymphocytes. Ultrastructural examination of the ciliary body of one horse confirmed the presence of abundant extracellular deposits of non-branching fibrils (9-11 nm in diameter) consistent with amyloid. Immunohistochemistry revealed strong positive labelling for AA amyloid and mass spectrometry showed the amyloid to consist primarily of serum amyloid A1 in both cases. The findings suggest that localized, intraocular AA amyloidosis may occur in horses with ERU. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Trans-oligomerization of duplicated aminoacyl-tRNA synthetases maintains genetic code fidelity under stress.

    PubMed

    Rubio, Miguel Ángel; Napolitano, Mauro; Ochoa de Alda, Jesús A G; Santamaría-Gómez, Javier; Patterson, Carl J; Foster, Andrew W; Bru-Martínez, Roque; Robinson, Nigel J; Luque, Ignacio

    2015-11-16

    Aminoacyl-tRNA synthetases (aaRSs) play a key role in deciphering the genetic message by producing charged tRNAs and are equipped with proofreading mechanisms to ensure correct pairing of tRNAs with their cognate amino acid. Duplicated aaRSs are very frequent in Nature, with 25,913 cases observed in 26,837 genomes. The oligomeric nature of many aaRSs raises the question of how the functioning and oligomerization of duplicated enzymes is organized. We characterized this issue in a model prokaryotic organism that expresses two different threonyl-tRNA synthetases, responsible for Thr-tRNA(Thr) synthesis: one accurate and constitutively expressed (T1) and another (T2) with impaired proofreading activity that also generates mischarged Ser-tRNA(Thr). Low zinc promotes dissociation of dimeric T1 into monomers deprived of aminoacylation activity and simultaneous induction of T2, which is active for aminoacylation under low zinc. T2 either forms homodimers or heterodimerizes with T1 subunits that provide essential proofreading activity in trans. These findings evidence that in organisms with duplicated genes, cells can orchestrate the assemblage of aaRSs oligomers that meet the necessities of the cell in each situation. We propose that controlled oligomerization of duplicated aaRSs is an adaptive mechanism that can potentially be expanded to the plethora of organisms with duplicated oligomeric aaRSs. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Corrosion Fatigue of Metals in Marine Environments

    DTIC Science & Technology

    1981-07-01

    Fatigue of Alloys 2014-T6 and 2024 -T4 in Air and Artificial Seawater I62 Fatigue Life of 2024 -T4 Aluminum Alloy Specimens... life was still considerably reduced. The effect of prior corrosion pitting on the fatigue life of Alloy 2024 -T4 was investigated by Harmsworth.215...Harmsworth, C. L, " Effect of Corrosion on the Fatigue Behavior of 2024 -T4 Aluminum Alloy ",

  17. Transcriptome profiling of the intoxication response of Tenebrio molitor larvae to Bacillus thuringiensis Cry3Aa protoxin.

    PubMed

    Oppert, Brenda; Dowd, Scot E; Bouffard, Pascal; Li, Lewyn; Conesa, Ana; Lorenzen, Marcé D; Toutges, Michelle; Marshall, Jeremy; Huestis, Diana L; Fabrick, Jeff; Oppert, Cris; Jurat-Fuentes, Juan Luis

    2012-01-01

    Bacillus thuringiensis (Bt) crystal (Cry) proteins are effective against a select number of insect pests, but improvements are needed to increase efficacy and decrease time to mortality for coleopteran pests. To gain insight into the Bt intoxication process in Coleoptera, we performed RNA-Seq on cDNA generated from the guts of Tenebrio molitor larvae that consumed either a control diet or a diet containing Cry3Aa protoxin. Approximately 134,090 and 124,287 sequence reads from the control and Cry3Aa-treated groups were assembled into 1,318 and 1,140 contigs, respectively. Enrichment analyses indicated that functions associated with mitochondrial respiration, signalling, maintenance of cell structure, membrane integrity, protein recycling/synthesis, and glycosyl hydrolases were significantly increased in Cry3Aa-treated larvae, whereas functions associated with many metabolic processes were reduced, especially glycolysis, tricarboxylic acid cycle, and fatty acid synthesis. Microarray analysis was used to evaluate temporal changes in gene expression after 6, 12 or 24 h of Cry3Aa exposure. Overall, microarray analysis indicated that transcripts related to allergens, chitin-binding proteins, glycosyl hydrolases, and tubulins were induced, and those related to immunity and metabolism were repressed in Cry3Aa-intoxicated larvae. The 24 h microarray data validated most of the RNA-Seq data. Of the three intoxication intervals, larvae demonstrated more differential expression of transcripts after 12 h exposure to Cry3Aa. Gene expression examined by three different methods in control vs. Cry3Aa-treated larvae at the 24 h time point indicated that transcripts encoding proteins with chitin-binding domain 3 were the most differentially expressed in Cry3Aa-intoxicated larvae. Overall, the data suggest that T. molitor larvae mount a complex response to Cry3Aa during the initial 24 h of intoxication. Data from this study represent the largest genetic sequence dataset for T. molitor

  18. Transcriptome Profiling of the Intoxication Response of Tenebrio molitor Larvae to Bacillus thuringiensis Cry3Aa Protoxin

    PubMed Central

    Oppert, Brenda; Dowd, Scot E.; Bouffard, Pascal; Li, Lewyn; Conesa, Ana; Lorenzen, Marcé D.; Toutges, Michelle; Marshall, Jeremy; Huestis, Diana L.; Fabrick, Jeff; Oppert, Cris; Jurat-Fuentes, Juan Luis

    2012-01-01

    Bacillus thuringiensis (Bt) crystal (Cry) proteins are effective against a select number of insect pests, but improvements are needed to increase efficacy and decrease time to mortality for coleopteran pests. To gain insight into the Bt intoxication process in Coleoptera, we performed RNA-Seq on cDNA generated from the guts of Tenebrio molitor larvae that consumed either a control diet or a diet containing Cry3Aa protoxin. Approximately 134,090 and 124,287 sequence reads from the control and Cry3Aa-treated groups were assembled into 1,318 and 1,140 contigs, respectively. Enrichment analyses indicated that functions associated with mitochondrial respiration, signalling, maintenance of cell structure, membrane integrity, protein recycling/synthesis, and glycosyl hydrolases were significantly increased in Cry3Aa-treated larvae, whereas functions associated with many metabolic processes were reduced, especially glycolysis, tricarboxylic acid cycle, and fatty acid synthesis. Microarray analysis was used to evaluate temporal changes in gene expression after 6, 12 or 24 h of Cry3Aa exposure. Overall, microarray analysis indicated that transcripts related to allergens, chitin-binding proteins, glycosyl hydrolases, and tubulins were induced, and those related to immunity and metabolism were repressed in Cry3Aa-intoxicated larvae. The 24 h microarray data validated most of the RNA-Seq data. Of the three intoxication intervals, larvae demonstrated more differential expression of transcripts after 12 h exposure to Cry3Aa. Gene expression examined by three different methods in control vs. Cry3Aa-treated larvae at the 24 h time point indicated that transcripts encoding proteins with chitin-binding domain 3 were the most differentially expressed in Cry3Aa-intoxicated larvae. Overall, the data suggest that T. molitor larvae mount a complex response to Cry3Aa during the initial 24 h of intoxication. Data from this study represent the largest genetic sequence dataset for T. molitor

  19. Immunomodulatory Effects of CP-25 on Splenic T Cells of Rats with Adjuvant Arthritis.

    PubMed

    Wang, Yang; Han, Chen-Chen; Cui, Dongqian; Luo, Ting-Ting; Li, Yifan; Zhang, Yuwen; Ma, Yang; Wei, Wei

    2018-06-01

    Rheumatoid arthritis (RA) is an autoimmune disease in which T cells play an important role. Paeoniflorin-6-oxy-benzenesulfonate (CP-25) shows a strong anti-inflammatory and immunomodulatory effect in the joint of adjuvant arthritis (AA) rats, but the role of the spleen function is still unclear. The aim of this study was to research how CP-25 regulated spleen function of AA rats. Male Sprague-Dawley rats were administered with CP-25 (50 mg/kg) orally from day 17 to 29 after immunization. The spleen histopathological changes were analyzed by hematoxylin-eosin staining. G protein-coupled receptor kinases (GRKs) and prostaglandin receptor subtypes (EPs) were screened by Western blot and immunohistochemistry. The co-expression of GRK2 and EP2 as well as GRK2 and EP4 was measured by immunofluorescence and co-immunoprecipitation. The expression of GRK2 and EP4 in splenic T cells was further detected by immunofluorescence. CP-25 was found to relieve the secondary paw swelling, attenuate histopathologic changes, and downregulate GRK2, EP2 and EP4 expression in AA rats. Additionally, CP-25 not only downregulated the co-expression of GRK2 and EP4 but also downregulated GRK2, EP4 expression in splenic T cells of AA rats. From these results, we can infer that CP-25 play an anti-inflammatory and immune function by affecting the function of the splenic T cells.

  20. Laboratory Astrophysics Division of The AAS (LAD)

    NASA Astrophysics Data System (ADS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-10-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  1. Laboratory Astrophysics Division of the AAS (LAD)

    NASA Technical Reports Server (NTRS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-01-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  2. Laser Direct Metal Deposition of 2024 Al Alloy: Trace Geometry Prediction via Machine Learning.

    PubMed

    Caiazzo, Fabrizia; Caggiano, Alessandra

    2018-03-19

    Laser direct metal deposition is an advanced additive manufacturing technology suitably applicable in maintenance, repair, and overhaul of high-cost products, allowing for minimal distortion of the workpiece, reduced heat affected zones, and superior surface quality. Special interest is growing for the repair and coating of 2024 aluminum alloy parts, extensively utilized for a wide range of applications in the automotive, military, and aerospace sectors due to its excellent plasticity, corrosion resistance, electric conductivity, and strength-to-weight ratio. A critical issue in the laser direct metal deposition process is related to the geometrical parameters of the cross-section of the deposited metal trace that should be controlled to meet the part specifications. In this research, a machine learning approach based on artificial neural networks is developed to find the correlation between the laser metal deposition process parameters and the output geometrical parameters of the deposited metal trace produced by laser direct metal deposition on 5-mm-thick 2024 aluminum alloy plates. The results show that the neural network-based machine learning paradigm is able to accurately estimate the appropriate process parameters required to obtain a specified geometry for the deposited metal trace.

  3. Laser Direct Metal Deposition of 2024 Al Alloy: Trace Geometry Prediction via Machine Learning

    PubMed Central

    2018-01-01

    Laser direct metal deposition is an advanced additive manufacturing technology suitably applicable in maintenance, repair, and overhaul of high-cost products, allowing for minimal distortion of the workpiece, reduced heat affected zones, and superior surface quality. Special interest is growing for the repair and coating of 2024 aluminum alloy parts, extensively utilized for a wide range of applications in the automotive, military, and aerospace sectors due to its excellent plasticity, corrosion resistance, electric conductivity, and strength-to-weight ratio. A critical issue in the laser direct metal deposition process is related to the geometrical parameters of the cross-section of the deposited metal trace that should be controlled to meet the part specifications. In this research, a machine learning approach based on artificial neural networks is developed to find the correlation between the laser metal deposition process parameters and the output geometrical parameters of the deposited metal trace produced by laser direct metal deposition on 5-mm-thick 2024 aluminum alloy plates. The results show that the neural network-based machine learning paradigm is able to accurately estimate the appropriate process parameters required to obtain a specified geometry for the deposited metal trace. PMID:29562682

  4. Abnormal Interactions between Perifollicular Mast Cells and CD8+ T-Cells May Contribute to the Pathogenesis of Alopecia Areata

    PubMed Central

    Bertolini, Marta; Zilio, Federica; Rossi, Alfredo; Gilhar, Amos; Keren, Aviad; Meyer, Katja C.; Wang, Eddy; Funk, Wolfgang; McElwee, Kevin; Paus, Ralf

    2014-01-01

    Alopecia areata (AA) is a CD8+ T-cell dependent autoimmune disease of the hair follicle (HF) in which the collapse of HF immune privilege (IP) plays a key role. Mast cells (MCs) are crucial immunomodulatory cells implicated in the regulation of T cell-dependent immunity, IP, and hair growth. Therefore, we explored the role of MCs in AA pathogenesis, focusing on MC interactions with CD8+ T-cells in vivo, in both human and mouse skin with AA lesions. Quantitative (immuno-)histomorphometry revealed that the number, degranulation and proliferation of perifollicular MCs are significantly increased in human AA lesions compared to healthy or non-lesional control skin, most prominently in subacute AA. In AA patients, perifollicular MCs showed decreased TGFβ1 and IL-10 but increased tryptase immunoreactivity, suggesting that MCs switch from an immuno-inhibitory to a pro-inflammatory phenotype. This concept was supported by a decreased number of IL-10+ and PD-L1+ MCs, while OX40L+, CD30L+, 4–1BBL+ or ICAM-1+ MCs were increased in AA. Lesional AA-HFs also displayed significantly more peri- and intrafollicular- CD8+ T-cells as well as more physical MC/CD8+ T-cell contacts than healthy or non-lesional human control skin. During the interaction with CD8+ T-cells, AA MCs prominently expressed MHC class I and OX40L, and sometimes 4–1BBL or ICAM-1, suggesting that MC may present autoantigens to CD8+ T-cells and/or co-stimulatory signals. Abnormal MC numbers, activities, and interactions with CD8+ T-cells were also seen in the grafted C3H/HeJ mouse model of AA and in a new humanized mouse model for AA. These phenomenological in vivo data suggest the novel AA pathobiology concept that perifollicular MCs are skewed towards pro-inflammatory activities that facilitate cross-talk with CD8+ T-cells in this disease, thus contributing to triggering HF-IP collapse in AA. If confirmed, MCs and their CD8+ T-cell interactions could become a promising new therapeutic target in the future

  5. Bacterial Heat Shock Protein GroEL (Hsp64) Exerts Immunoregulatory Effects on T Cells by Utilizing Apoptosis

    PubMed Central

    Nalbant, Ayten; Kant, Melis

    2016-01-01

    Aggregatibacter actinomycetemcomitans (Aa) expresses a 64-kDa GroEL protein belonging to the heat shock family of proteins. This protein has been shown to influence human host cells, but the apoptotic capacity of the GroEL protein regarding T cells is not yet known. The purpose of this study was to investigate the ability of A. actinomycetemcomitans GroEL (AaGroEL) protein to induce human peripheral blood T-cell apoptosis. Endogenous, purified AaGroEL protein was used as an antigen. In AaGroEL-treated T cells, the data indicated that phosphatidylserine exposure, an early apoptotic event, was dose- and time-dependent. The AaGroEL-treated T cells were also positive for active caspase-3 in a dose-dependent manner. The rate of AaGroEL-induced apoptosis was suppressed by the addition of the general caspase inhibitor Z-VAD-FMK. Furthermore, cleaved caspase-8 bands (40/36 kDa and 23 kDa) were identified in cells responding to AaGroEL. DNA fragmentation was also detected in the AaGroEL-treated T cells. Overall, we demonstrated that the endogenous GroEL from A. actinomycetemcomitans has the capacity to induce T-cell apoptosis. PMID:27736933

  6. Assessment of Damage Tolerance Requirements and Analysis. Volume 4. Raw Test Data

    DTIC Science & Technology

    1986-03-31

    T3XX aluminum alloy . Four (4) product forms were selected: MATERIAL PRODUCT FORM THICKNESS (IN) 2024-T3 Sheet 0.090, 0.190 2024-T351 Plate 0.250 2024...T3511 Extruded Tee 0.190 2024-T3511 Extruded Angle 0.250 The material selected to represent bomber/transport/cargo aircraft is 7075- T6XX aluminum alloy ...aluminum alloys , respectively. The raw test data were processed in accordance with ASTM Standard E-8. All the tensile properties, except those marked

  7. 40 CFR 35.2024 - Combined sewer overflows.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... project priority list, it addresses impaired uses in priority water quality areas which are due to the... must demonstrate to the Administrator that the water quality goals of the Act will not be achieved... priority water quality areas in marine bays and estuaries due to the impacts of combined sewer overflows...

  8. Heat Treatment of Gas-Atomized Powders for Cold Spray Deposition

    NASA Astrophysics Data System (ADS)

    Story, William A.; Brewer, Luke N.

    2018-02-01

    This communication demonstrates the efficacy of heat treatment on the improved deposition characteristics of aluminum alloy powders. A novel furnace was constructed for solutionizing of feedstock powders in an inert atmosphere while avoiding sintering. This furnace design achieved sufficiently high cooling rates to limit re-precipitation during powder cooling. Microscopy showed homogenization of the powder particle microstructures after heat treatment. Cold spray deposition efficiency with heat-treated powders substantially increased for the alloys AA2024, AA6061, and AA7075.

  9. Homocysteine induced cardiovascular events: a consequence of long term anabolic‐androgenic steroid (AAS) abuse

    PubMed Central

    Graham, M R; Grace, F M; Boobier, W; Hullin, D; Kicman, A; Cowan, D; Davies, B; Baker, J S

    2006-01-01

    Objectives The long term effects (>20 years) of anabolic‐androgenic steroid (AAS) use on plasma concentrations of homocysteine (HCY), folate, testosterone, sex hormone binding globulin (SHBG), free androgen index, urea, creatinine, haematocrit (HCT), vitamin B12, and urinary testosterone/epitestosterone (T/E) ratio, were examined in a cohort of self‐prescribing bodybuilders. Methods Subjects (n = 40) were divided into four distinct groups: (1) AAS users still using AAS (SU; n = 10); (2) AAS users abstinent from AAS administration for 3 months (SA; n = 10); (3) non‐drug using bodybuilding controls (BC; n = 10); and (4) sedentary male controls (SC; n = 10). Results HCY levels were significantly higher in SU compared with BC and SC (p<0.01), and with SA (p<0.05). Fat free mass was significantly higher in both groups of AAS users (p<0.01). Daily energy intake (kJ) and daily protein intake (g/day) were significantly higher in SU and SA (p<0.05) compared with BC and SC, but were unlikely to be responsible for the observed HCY increases. HCT concentrations were significantly higher in the SU group (p<0.01). A significant linear inverse relationship was observed in the SU group between SHBG and HCY (r = −0.828, p<0.01), indicating a possible influence of the sex hormones in determining HCY levels. Conclusions With mounting evidence linking AAS to adverse effects on some clotting factors, the significantly higher levels of HCY and HCT observed in the SU group suggest long term AAS users have increased risk of future thromboembolic events. PMID:16488899

  10. Clinical implications of eicosapentaenoic acid/arachidonic acid ratio (EPA/AA) in adult patients with congenital heart disease.

    PubMed

    Kanoh, Miki; Inai, Kei; Shinohara, Tokuko; Tomimatsu, Hirofumi; Nakanishi, Toshio

    2017-12-01

    Recent studies showed that a low ratio between the levels of eicosapentaenoic acid and those of arachidonic acid (EPA/AA) is associated with higher incidence of coronary artery disease and poor prognosis of heart failure, arrhythmia, and cardiac sudden death. However, the clinical implications of EPA/AA in adult patients with congenital heart disease remain unclear. We aimed to assess the prognostic value of EPA/AA regarding cardiac events in adult patients with congenital heart disease. We measured the serum levels of eicosapentaenoic acid and arachidonic acid in 130 adult patients (median age, 31 years) stratified into two groups according to their EPA/AA (low, ≤0.22; high, >0.22). We prospectively analyzed the association between EPA/AA and incidence of cardiac events during a mean observation period of 15 months, expressed in terms of hazard ratio (HR) with 95% confidence interval (95% CI). In the subgroup of patients with biventricular circulation (2VC) (n = 76), we analyzed the same clinical endpoints. In our study population, EPA/AA was not associated with the incidence of arrhythmic events (HR, 1.52; 95% CI, 0.82-2.85; p = 0.19), but low EPA/AA was a predictor of heart failure hospitalization (HR, 2.83; 95% CI, 1.35-6.30; p < 0.01). Among patients with 2VC, an EPA/AA of ≤0.25 was associated with a significantly higher risk of arrhythmic events (HR, 2.55; 95% CI, 1.11-6.41; p = 0.03) and heart failure hospitalization (HR, 5.20; 95% CI, 1.78-18.1; p < 0.01). EPA/AA represents a useful predictor of cardiac events in adult patients with congenital heart disease.

  11. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment ENVIRONMENTAL... Manufacturing Pt. 98, Subpt. AA, Table AA -2 Table AA-2 to Subpart AA of Part 98—Kraft Lime Kiln and Calciner...

  12. [AA amyloidosis].

    PubMed

    Stojanovic, Katia Stankovic; Georgin-Lavialle, Sophie; Grateau, Gilles

    2017-06-01

    AA amyloidosis remains one of the three main types of systemic amyloidosis with AL and ATTR. Its incidence has been however decreasing recently in Western countries. Chronic inflammatory diseases are currently the first cause of AA amyloidosis, including rheumatoid arthritis, spondyloarthritis and autoinflammatory diseases. Castleman's disease is a specific cause of AA amyloidosis that can be cured by surgery. A chronic inflammatory response is required to develop amyloidosis. Other genetic and environmental factors are also involved. The first clinical manifestation is a chronic glomerular nephropathy, which can be detected by urine examination and serum creatinine measure. Immunohistochemistry is mandatory to confirm the clinical diagnosis of AA amyloidosis and to avoid misdiagnosis. Long-term prognosis remains poor on chronic dialysis in case of clinical gut involvement. Current treatment is based on the control of the inflammatory response. Specific treatment aimed at inhibiting amyloid formation targeting serum amyloid P component and heparan sulphate are currently evaluated. Copyright © 2017 Société francophone de néphrologie, dialyse et transplantation. Published by Elsevier Masson SAS. All rights reserved.

  13. Interactions between the APOA5 -1131T>C and the FEN1 10154G>T polymorphisms on ω6 polyunsaturated fatty acids in serum phospholipids and coronary artery disease

    PubMed Central

    Park, Ju Yeon; Paik, Jean Kyung; Kim, Oh Yoen; Chae, Jey Sook; Jang, Yangsoo; Lee, Jong Ho

    2010-01-01

    We determined the contribution of the combination of FEN1 10154G>T with the most significant association in the analysis of plasma arachidonic acid (AA, 20:4ω6) and the APOA5-1131T>C on phospholipid ω6PUFA and coronary artery disease (CAD). Patients with CAD (n = 807, 27–81 years of age) and healthy controls (n = 1123) were genotyped for FEN1 10154G>T and APOA5-1131T>C. We found a significant interaction between these two genes for CAD risk (P = 0.007) adjusted for confounding factors. APOA5-1131C allele carriers had a higher CAD risk [odds ratio (OR):1.484, 95% confidence interval (CI):1.31–1.96; P = 0.005] compared with APOA5-1131TT individuals in the FEN1 10154GG genotype group but not in the FEN1 10154T allele group (OR:1.096, 95%CI:0.84–1.43; P = 0.504). Significant interactions between these two genes were also observed for the AA proportion (P = 0.04) and the ratio of AA/linoleic acid (LA, 18:2ω6) (P = 0.004) in serum phospholipids of controls. The APOA5-1131C allele was associated with lower AA (P = 0.027) and AA/LA (P = 0.014) only in controls carrying the FEN1 10154T allele. In conclusion, the interaction between these genes suggests that the FEN1 10154T variant allele decreases AA and AA/LA in the serum phospholipids of carriers of the APOA5-1131C allele, but contributes no significant increase in CAD risk for this population subset despite their increased triglylcerides and decreased apoA5. PMID:20802161

  14. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40 CFR...

  15. 40 CFR Appendix A to Subpart Aa of... - Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (40 CFR Part 63, Subpart A) to Subpart AA A Appendix A to Subpart AA of Part 63 Protection of... Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants Pt. 63, Subpt. AA, App. A Appendix A to Subpart AA of Part 63—Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart AA 40 CFR...

  16. AAS Statistics and the 60% Cohort

    NASA Astrophysics Data System (ADS)

    Marvel, K. B.

    2004-05-01

    I will present the latest statistics available describing the gender of the AAS membership including an update on the so-called 60% cohort (that group of AAS members from the ages of 18 to 25 who are 60% women and 40% men). The AAS membership has changed significantly in the past 30 years from an overall female membership percentage of about 10% to a level around 30% today. This trend is accelerating and indicates the ongoing inclusion of women in the physical sciences, especially astronomy. By the year 2030, the AAS membership should reach gender parity if the present trend continues.

  17. A flattened cloud core in NGC 2024

    NASA Technical Reports Server (NTRS)

    Ho, Paul T. P.; Peng, Yun-Lou; Torrelles, Jose M.; Gomez, Jose F.; Rodriguez, Luis F.; Canto, Jorge

    1993-01-01

    The (J, K) (1, 1) and (2, 2) NH3 lines were mapped toward a molecular cloud core in NGC 2024 using the VLA in its C/D-configuration. This region is associated with one of the most highly collimated molecular outflows. We find that the molecular condensations associated with the far-infrared sources FIR 5, FIR 6, and FIR 7 have kinetic temperatures of about 40 K. We also find line broadening toward FIR 6 and FIR 7. This suggests that these condensations may not be protostars heated by gravitational energy released during collapse but that they have an internal heating source. A flattened structure of ammonia emission is found extending parallel to the unipolar CO outflow structure, but displaced systematically to the east. If the NH3 emission traces the denser gas environment, there is no evidence that a dense gas structure is confining the molecular outflow. Instead, the location of the high-velocity outflow along the surface of the NH3 structure suggests that a wind is sweeping material from the surface of this elongated cloud core.

  18. Activity of vegetative insecticidal proteins Vip3Aa58 and Vip3Aa59 of Bacillus thuringiensis against lepidopteran pests.

    PubMed

    Baranek, Jakub; Kaznowski, Adam; Konecka, Edyta; Naimov, Samir

    2015-09-01

    Vegetative insecticidal proteins (Vips) secreted by some isolates of Bacillus thuringiensis show activity against insects and are regarded as insecticides against pests. A number of B. thuringiensis strains harbouring vip3A genes were isolated from different sources and identified by using a PCR based approach. The isolates with the highest insecticidal activity were indicated in screening tests, and their vip genes were cloned and sequenced. The analysis revealed two polymorphic Vip protein forms, which were classified as Vip3Aa58 and Vip3Aa59. After expression of the vip genes, the proteins were isolated and characterized. The activity of both toxins was estimated against economically important lepidopteran pests of woodlands (Dendrolimus pini), orchards (Cydia pomonella) and field crops (Spodoptera exigua). Vip3Aa58 and Vip3Aa59 were highly toxic and their potency surpassed those of many Cry proteins used in commercial bioinsecticides. Vip3Aa59 revealed similar larvicidal activity as Vip3Aa58 against S. exigua and C. pomonella. Despite 98% similarity of amino acid sequences of both proteins, Vip3Aa59 was significantly more active against D. pini. Additionally the effect of proteolytic activation of Vip58Aa and Vip3Aa59 on toxicity of D. pini and S. exigua was studied. Both Vip3Aa proteins did not show any activity against Tenebrio molitor (Coleoptera) larvae. The results suggest that the Vip3Aa58 and Vip3Aa59 toxins might be useful for controlling populations of insect pests of crops and forests. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Effects Of Welding On The Fatigue Behaviour Of Commercial Aluminum AA-1100 Joints

    NASA Astrophysics Data System (ADS)

    Uthayakumar, M.; Balasubramanian, V.; Rani, Ahmad Majdi Abdul; Hadzima, Branislav

    2018-04-01

    Friction Stir Welding (FSW) is an budding solid state welding process, which is frequently used for joining aluminum alloys where materials can be joined without melt and recast. Therefore, when welding alloys through FSW the phase transformations occurs will be in the solid state form. The present work is aimed in evaluating the fatigue life of friction stir welded commercial grade aluminum alloy joints. The commercial grade AA1100 aluminum alloy of 12mm thickness plate is welded and the specimens are tested using a rotary beam fatigue testing machine at different stress levels. The stress versus number of cycles (S-N) curves was plotted using the data points. The Fatigue life of tungsten inert gas (TIG) and metal inert gas (MIG) welded joints was compared. The fatigue life of the weld joints was interrelated with the tensile properties, microstructure and micro hardness properties. The effects of the notches and welding processes are evaluated and reported.

  20. Effect of Chromate and Chromate-Free Organic Coatings on Corrosion Fatigue of an Aluminum Alloy

    DTIC Science & Technology

    2012-02-20

    Investigations of alloy AA7075 corrosion in acid rain solution, inhibited by chromate-free blends of zinc phosphate with bentonite, zeolite and calcium...with solution components. Single use of zinc phosphate and these ion exchanged pigments for corrosion inhibition do not provide desired effect...primer performance against corrosion fatigue cracking under a commercial polyurethane topcoat. As a control , they used samples of chromated AA2024

  1. The effect of welding parameters on surface quality of AA6351 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Yacob, S.; MAli, M. A.; Ahsan, Q.; Ariffin, N.; Ali, R.; Arshad, A.; Wahab, M. I. A.; Ismail, S. A.; Roji, NS M.; Din, W. B. W.; Zakaria, M. H.; Abdullah, A.; Yusof, M. I.; Kamarulzaman, K. Z.; Mahyuddin, A.; Hamzah, M. N.; Roslan, R.

    2015-12-01

    In the present work, the effects of gas metal arc welding-cold metal transfer (GMAW-CMT) parameters on surface roughness are experimentally assessed. The purpose of this study is to develop a better understanding of the effects of welding speed, material thickness and contact tip to work distance on the surface roughness. Experiments are conducted using single pass gas metal arc welding-cold metal transfer (GMAW-CMT) welding technique to join the material. The material used in this experiment was AA6351 aluminum alloy with the thickness of 5mm and 6mm. A Mahr Marsuft XR 20 machine was used to measure the average roughness (Ra) of AA6351 joints. The main and interaction effect analysis was carried out to identify process parameters that affect the surface roughness. The results show that all the input process parameters affect the surface roughness of AA6351 joints. Additionally, the average roughness (Ra) results also show a decreasing trend with increased of welding speed. It is proven that gas metal arc welding-cold metal transfer (GMAW-CMT)welding process has been successful in term of providing weld joint of good surface quality for AA6351 based on the low value surface roughness condition obtained in this setup. The outcome of this experimental shall be valuable for future fabrication process in order to obtained high good quality weld.

  2. Identification of GAD65 AA 114-122 reactive 'memory-like' NK cells in newly diagnosed Type 1 diabetic patients by HLA-class I pentamers.

    PubMed

    Perri, Valentina; Gianchecchi, Elena; Cifaldi, Loredana; Pellegrino, Marsha; Giorda, Ezio; Andreani, Marco; Cappa, Marco; Fierabracci, Alessandra

    2017-01-01

    Type 1 diabetes is an autoimmune disease, in which pancreatic β cells are destroyed by autoreactive T cells in genetically predisposed individuals. Serum beta cell autoantibody specificities have represented the mainstay for classifying diabetes as autoimmune-mediated and for stratifying risk in first-degree relatives. In recent years, approaches were attempted to solve the difficult issue of detecting rare antigen-specific autoreactive T cells and their significance to etiopathogenesis such as the use of the MHC multimer technology. This tool allowed the specific detection of increased percentages of GAD65 autoreactive T cells by means of HLA A*02:01 GAD65 AA 114-122 pentamers in newly diagnosed diabetics. Here we provide evidence that GAD65 AA 114-122 pentamers can depict a GAD65 AA114-122 peptide expandable population of functionally and phenotypically skewed, preliminary characterized CD3-CD8dullCD56+ 'memory-like' NK cells in PBMC of newly diagnosed diabetics. Our data suggest that the NK cell subset could bind the HLA class I GAD65 AA 114-122 pentamer through ILT2 inhibitory receptor. CD107a expression revealed increased degranulation of CD3-CD8dullCD56+ NK cells in GAD65 AA 114-122 and FLU peptide expanded peripheral blood mononuclear cells of diabetics following GAD65 AA 114-122 peptide HLA A*02:01 presentation in respect to the unpulsed condition. CD107a expression was enriched in ILT2 positive NK cells. As opposite to basal conditions where similar percentages of CD3-CD56+ILT2+ cells were detected in diabetics and controls, CD3-CD56+CD107a+ and CD3-CD56+ILT2+CD107a+ cells were significantly increased in T1D PBMC either GAD65 AA 114-122 or FLU peptides stimulated after co-culture with GAD65 AA 114-122 pulsed APCs. As control, healthy donor NK cells showed similar degranulation against both GAD65 AA 114-122 pulsed and unpulsed APCs. The pathogenetic significance of the CD3-CD8dullCD56+ 'memory-like NK cell subset' with increased response upon secondary

  3. Interleukin 35 (IL-35) and IL-37: Intestinal and peripheral expression by T and B regulatory cells in patients with Inflammatory Bowel Disease.

    PubMed

    Fonseca-Camarillo, Gabriela; Furuzawa-Carballeda, Janette; Yamamoto-Furusho, Jesús K

    2015-10-01

    The aim of the study was to characterize and to quantify peripheral and tissue. IL-35- and IL-37-producing cells in Inflammatory Bowel Disease (IBD) patients. We studied a total of 38 active UC, 31 inactive UC, 17 active CD, and 13 inactive CD and 50 non-inflamed tissues as control group. Gene expression was measured by real time polymerase chain reaction (RT-PCR) and protein expression was evaluated in tissue by immunohistochemistry and in peripheral blood mononuclear cells by flow cytometry. Higher levels of IL-35 was produced by intestinal regulatory B cells and circulating regulatory CD4(+) and CD8(+) T cells in active vs. inactive disease or healthy donors (P<0.05). The IL-37 was conspicuously synthesized by circulating B cells, active natural killer cells and monocytes. These results suggest that down-regulation of inflammation in active IBD patients might be based on the increased expression of IL-35 and IL-37. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. An alternate to chromate conversion coatings for the corrosion protection of aluminum 2024-T3

    NASA Astrophysics Data System (ADS)

    Guo, Ruiguang

    Corrosion of high-strength aluminum alloys used for airspace application is an expensive and serious problem. The most significant environmental factor contributing to the corrosion of these alloys is water condensed from humid air and contaminated with soluble chloride salts. The Al 2024 series used for aircraft are particularly susceptible to corrosion in aqueous chloride solutions due to alloying constituents such as copper and other impurities. Chromates are efficient inhibitors of corrosion of aluminum in near neutral aqueous environments containing aggressive anions such as chlorides. Usually, aluminum alloys are initially protected by chromate conversion coatings. Additional polymer coatings are sometimes added during exposure to corrosive atmospheres such as marine environments. Although chromate coatings are widely used, they require the use of noxious solutions, so they have always presented effluent disposal problems. There are health and safety concerns over the use of chromates due to their toxicity and carcinogenic nature and, as a consequence, the environmental and health risks associated with the use of such coatings will be restricted in the future. It was these health and safety concerns that led to the development of alternative non-toxic coating processes with comparable adhesion properties and corrosion protection. A variety of process technologies are under development and are vying for acceptance in industrial markets. As an alternate conversion coating, a new titanate conversion coating was systematically researched and developed. Research concentrated on producing passive surfaces from a simple titanate solution using an immersion process. The corrosion resistance of the treated surface has been evaluated using simple, rapid electrochemical techniques as well as a more long-term salt spray test. Passivation by titanate conversion treatment exhibits many similarities to chromate conversion treatment. Based on this study of corrosion

  5. A Geometric Approach to Modeling Microstructurally Small Fatigue Crack Formation. 2; Simulation and Prediction of Crack Nucleation in AA 7075-T651

    NASA Technical Reports Server (NTRS)

    Hochhalter, Jake D.; Littlewood, David J.; Christ, Robert J., Jr.; Veilleux, M. G.; Bozek, J. E.; Ingraffea, A. R.; Maniatty, Antionette M.

    2010-01-01

    The objective of this paper is to develop further a framework for computationally modeling microstructurally small fatigue crack growth in AA 7075-T651 [1]. The focus is on the nucleation event, when a crack extends from within a second-phase particle into a surrounding grain, since this has been observed to be an initiating mechanism for fatigue crack growth in this alloy. It is hypothesized that nucleation can be predicted by computing a non-local nucleation metric near the crack front. The hypothesis is tested by employing a combination of experimentation and nite element modeling in which various slip-based and energy-based nucleation metrics are tested for validity, where each metric is derived from a continuum crystal plasticity formulation. To investigate each metric, a non-local procedure is developed for the calculation of nucleation metrics in the neighborhood of a crack front. Initially, an idealized baseline model consisting of a single grain containing a semi-ellipsoidal surface particle is studied to investigate the dependence of each nucleation metric on lattice orientation, number of load cycles, and non-local regularization method. This is followed by a comparison of experimental observations and computational results for microstructural models constructed by replicating the observed microstructural geometry near second-phase particles in fatigue specimens. It is found that orientation strongly influences the direction of slip localization and, as a result, in uences the nucleation mechanism. Also, the baseline models, replication models, and past experimental observation consistently suggest that a set of particular grain orientations is most likely to nucleate fatigue cracks. It is found that a continuum crystal plasticity model and a non-local nucleation metric can be used to predict the nucleation event in AA 7075-T651. However, nucleation metric threshold values that correspond to various nucleation governing mechanisms must be calibrated.

  6. Residual Ductility and Microstructural Evolution in Continuous-Bending-under-Tension of AA-6022-T4

    PubMed Central

    Zecevic, Milovan; Roemer, Timothy J.; Knezevic, Marko; Korkolis, Yannis P.; Kinsey, Brad L.

    2016-01-01

    A ubiquitous experiment to characterize the formability of sheet metal is the simple tension test. Past research has shown that if the material is repeatedly bent and unbent during this test (i.e., Continuous-Bending-under-Tension, CBT), the percent elongation at failure can significantly increase. In this paper, this phenomenon is evaluated in detail for AA-6022-T4 sheets using a custom-built CBT device. In particular, the residual ductility of specimens that are subjected to CBT processing is investigated. This is achieved by subjecting a specimen to CBT processing and then creating subsize tensile test and microstructural samples from the specimens after varying numbers of CBT cycles. Interestingly, the engineering stress initially increases after CBT processing to a certain number of cycles, but then decreases with less elongation achieved for increasing numbers of CBT cycles. Additionally, a detailed microstructure and texture characterization are performed using standard scanning electron microscopy and electron backscattered diffraction imaging. The results show that the material under CBT preserves high integrity to large plastic strains due to a uniform distribution of damage formation and evolution in the material. The ability to delay ductile fracture during the CBT process to large plastic strains, results in formation of a strong <111> fiber texture throughout the material. PMID:28773257

  7. Investigation into the stress corrosion cracking properties of AA2099, an aluminum-lithium-copper alloy

    NASA Astrophysics Data System (ADS)

    Padgett, Barbara Nicole

    Recently developed Al-Li-Cu alloys show great potential for implementation in the aerospace industry because of the attractive mix of good mechanical properties and low density. AA2099 is an Al-Li-Cu alloy with the following composition Al-2.69wt%Cu-1.8wt%Li-0.6wt%Zn-0.3wt%Mg-0.3wt%Mn-0.08wt%Zr. The environmental assisted cracking and localized corrosion behavior of the AA2099 was investigated in this thesis. The consequences of uncontrolled grain boundary precipitation via friction stir welding on the stress corrosion cracking (SCC) behavior of AA2099 was investigated first. Using constant extension rate testing, intergranular corrosion immersion experiments, and potentiodynamic scans, the heat-affected zone on the trailing edge of the weld (HTS) was determined to be most susceptible of the weld zones. The observed SCC behavior for the HTS was linked to the dissolution of an active phase (Al2CuLi, T1) populating the grain boundary. It should be stated that the SCC properties of AA2099 in the as-received condition were determined to be good. Focus was then given to the electrochemical behavior of precipitate phases that may occupy grain and sub-grain boundaries in AA2099. The grain boundary micro-chemistry and micro-electrochemistry have been alluded to within the literature as having significant influence on the SCC behavior of Al-Li-Cu alloys. Major precipitates found in this alloy system are T1 (Al 2CuLi), T2 (Al7.5Cu4Li), T B (Al6CuLi3), and theta (Al2 Cu). These phases were produced in bulk form so that the electrochemical nature of each phase could be characterized. It was determined T1 was most active electrochemically and theta was least. When present on grain boundaries in the alloy, electrochemical behavior of the individual precipitates aligned with the observed corrosion behavior of the alloy (e.g. TB was accompanied by general pitting corrosion and T 1 was accompanied by intergranular corrosion attack). In addition to the electrochemical behavior of

  8. Laser irradiation effects on the surface, structural and mechanical properties of Al-Cu alloy 2024

    NASA Astrophysics Data System (ADS)

    Yousaf, Daniel; Bashir, Shazia; Akram, Mahreen; kalsoom, Umm-i.-; Ali, Nisar

    2014-02-01

    Laser irradiation effects on surface, structural and mechanical properties of Al-Cu-Mg alloy (Al-Cu alloy 2024) have been investigated. The specimens were irradiated for various fluences ranging from 3.8 to 5.5 J/cm2 using an Excimer (KrF) laser (248 nm, 18 ns, 30 Hz) under vacuum environment. The surface and structural modifications of the irradiated targets have been investigated by scanning electron microscope (SEM) and X-ray diffractometer (XRD), respectively. SEM analysis reveals the formation of micro-sized craters along the growth of periodic surface structures (ripples) at their peripheries. The size of the craters initially increases and then decreases by increasing the laser fluence. XRD analysis shows an anomalous trend in the peak intensity and crystallite size of the specimen irradiated for various fluences. A universal tensile testing machine and Vickers microhardness tester were employed in order to investigate the mechanical properties of the irradiated targets. The changes in yield strength, ultimate tensile strength and microhardness were found to be anomalous with increasing laser fluences. The changes in the surface and structural properties of Al-Cu alloy 2024 after laser irradiation have been associated with the changes in mechanical properties.

  9. Manufacturing Systems Demonstration: Bimetallic Friction STIR Joining of AA6061 and High Hardness Steel

    DTIC Science & Technology

    2013-05-31

    fusion welding and virtually eliminates the material porosity inherent with liquid alloy processes. Also because less heat is input to the material...Fe intermetallic present. Mechanical load testing determined that the bimetallic FSP joint was stronger than similar AA6061-to-AA6061 fusion- welded and...5 b) Weld Coupon Fixture ........................................................................................ 5 2. Friction Stir Tools

  10. In-Situ Neutron Diffraction Studies of Micromechanical Behavior in a Friction Stir Welded AA7475-T761

    NASA Astrophysics Data System (ADS)

    Liu, X. P.; Lin Peng, R.; Hofmann, M.; Johansson, S.; Wang, Y. D.

    2011-01-01

    An in-situ neutron diffraction technique was used to investigate the lattice strain distributions and micromechanical behavior in a friction stir welded (FSW) sheet of AA7475-T761. The neutron diffraction experiments were performed on the spectrometer for material research, STRESS-SPEC, at FRM II (Garching, Germany). The lattice strain profiles around the weld center were measured as a function of the applied strain during the tensile loading and unloading. The anisotropic elastic and plastic properties of the FSW aluminum alloy were simulated by elasto-plastic self-consistent (EPSC) model to predict the anisotropic deformation behaviors involving the grain-to-grain interactions. Material parameters used for describing the constitutive laws of each test position were determined from the measured lattice strain distributions for different diffraction hkl planes as well as the macroscopic stress-strain curve of the FSW aluminum alloy. A good agreement between experimental results and numerical simulations was obtained. The present investigations provided a reliable prediction of the anisotropic micromechanical behavior of the FSW aluminum alloy during tensile deformation.

  11. AAS and spectrophotometric methods for the determination metoprolol tartrate in tablets

    NASA Astrophysics Data System (ADS)

    Alpdoğan, Güzin; Sungur, Sidika

    1999-11-01

    Sensitive and specific atomic adsorption spectroscopy (AAS) and spectrophotometric methods have been developed for the determination of beta adrenergic blocking drug, metoprolol tartrate.The method is based on the formation of Cu(II) dithiocarbamate complex by derivatization of the secondary amino group of metoprolol with CS 2 and CuCl 2 in the presence of ammonia.The copper-bis(dithiocarbamate) complex was extracted into chloroform and the concentration of metoprolol tartrate was determined directly by spectrophotometric and indirectly by AAS measurement of copper.The two methods developed were applied to the assay of metoprolol tartrate in commercial tablet formulations.The methods were compared statistically with each other and with the high performance liquid chromatography (HPLC) method of USPXXII using t- and F-tests.

  12. Determination of the Corrosive Conditions Present within Aircraft Lap-Splice Joints

    NASA Technical Reports Server (NTRS)

    Lewis, Karen S.; Kelly, Robert G.; Piascik, Robert S.

    1999-01-01

    The complexity of airframe structure lends itself to damage resulting from crevice corrosion. Fuselage lap-splice joints are a particularly important structural detail in this regard because of the difficulty associated with detection and measurement of corrosion in these occluded regions. The objective of this work is to develop a laboratory corrosion test protocol to identify the chemistry to which lap joints are exposed and to develop a model of the corrosion within the joints. A protocol for collecting and identifying the chemistry of airframe crevice corrosion has been developed. Capillary electrophoresis (CE) is used to identify the ionic species contained in corrosion product samples removed from fuselage lap splice joints. CE analysis has been performed on over sixty corrosion product samples removed from both civilian and military aircraft. Over twenty different ions have been detected. Measurements of pH of wetted corroded surfaces indicated an alkaline occluded solution. After determining the species present and their relative concentrations, the resultant solution was reproduced in bulk and electrochemical tests were performed to determine the corrosion rate. Electrochemical analyses of the behavior of AA2024-T3 in these solutions gave corrosion rates of up to 250 microns per year (10 mpy). Additional tests have determined the relative importance of each of the detected ions in model solutions used for future predictive tests. The statistically significant ions have been used to create a second generation solution. Laboratory studies have also included exposure tests involving artificial lap joints exposed to various simulated bulk and crevice environments. The extent and morphology of the attack in artificial lap joints has been compared to studies of corroded samples from actual aircraft. Other effects, such as temperature and potential, as well as the impact of the environment on fatigue crack growth have also been studied.

  13. Designer tRNAs for efficient incorporation of non-canonical amino acids by the pyrrolysine system in mammalian cells

    PubMed Central

    Serfling, Robert; Lorenz, Christian; Etzel, Maja; Schicht, Gerda; Böttke, Thore; Mörl, Mario

    2018-01-01

    Abstract The pyrrolysyl-tRNA synthetase/tRNAPyl pair is the most versatile and widespread system for the incorporation of non-canonical amino acids (ncAAs) into proteins in mammalian cells. However, low yields of ncAA incorporation severely limit its applicability to relevant biological targets. Here, we generate two tRNAPyl variants that significantly boost the performance of the pyrrolysine system. Compared to the original tRNAPyl, the engineered tRNAs feature a canonical hinge between D- and T-loop, show higher intracellular concentrations and bear partially distinct post-transcriptional modifications. Using the new tRNAs, we demonstrate efficient ncAA incorporation into a G-protein coupled receptor (GPCR) and simultaneous ncAA incorporation at two GPCR sites. Moreover, by incorporating last-generation ncAAs for bioorthogonal chemistry, we achieve GPCR labeling with small organic fluorophores on the live cell and visualize stimulus-induced GPCR internalization. Such a robust system for incorporation of single or multiple ncAAs will facilitate the application of a wide pool of chemical tools for structural and functional studies of challenging biological targets in live mammalian cells. PMID:29177436

  14. Efficacy of etanercept in patients with AA amyloidosis secondary to rheumatoid arthritis.

    PubMed

    Nakamura, T; Higashi, S; Tomoda, K; Tsukano, M; Baba, S

    2007-01-01

    The efficacy of biological therapies in rheumatoid arthritis (RA) is well known, but their hypothetical benefit in amyloid A (AA) amyloidosis secondary to RA still remains to be considered. We evaluated the efficacy and safety of etanercept in serum amyloid A (SAA) 1.3 allele Japanese patients with AA amyloidosis secondary to RA. Seven RA patients with histologically confirmed AA amyloidosis and renal involvement who were treated with etanercept were enrolled. They all had the SAA1.3 allele, which has been shown to be a risk factor not only for the association of AA amyloidosis but also for a poor prognosis in Japanese RA patients. Efficacy was assessed as a sustained decrease in RA inflammation and an amelioration of renal function. RA inflammation and AA amyloidosis were improved and stabilized after 43.4 +/- 16.5 weeks. At week 20 the number of tender (p = 0.017) and swollen (p = 0.017) joints, and levels of serum C-reactive protein (p = 0.018) and albumin (p = 0.045) had improved. The values for SAA, serum creatinine, calculated creatinine clearance, and proteinuria also ameliorated. No severe adverse events were observed. One patient eventually had to go on hemodialysis but her tolerance of etanercept remained stable. Etanercept can be used safely and effectively in AA amyloidosis secondary to RA with renal involvement, and is of clinical benefit in the short-term, even in patients on hemodialysis. It appears that SAA1.3 allele may be used as a clinical parameter for the introduction of etanercept in Japanese RA with AA amyloidosis.

  15. Experimental transmission of AA amyloidosis by injecting the AA amyloid protein into interleukin-1 receptor antagonist knockout (IL-1raKO) mice.

    PubMed

    Watanabe, K; Uchida, K; Chambers, J K; Tei, M; Shoji, A; Ushio, N; Nakayama, H

    2015-05-01

    The incidence of AA amyloidosis is high in humans with rheumatoid arthritis and several animal species, including cats and cattle with prolonged inflammation. AA amyloidosis can be experimentally induced in mice using severe inflammatory stimuli and a coinjection of AA amyloid; however, difficulties have been associated with transmitting AA amyloidosis to a different animal species, and this has been attributed to the "species barrier." The interleukin-1 receptor antagonist knockout (IL-1raKO) mouse, a rodent model of human rheumatoid arthritis, has been used in the transmission of AA amyloid. When IL-1raKO and BALB/c mice were intraperitoneally injected with mouse AA amyloid together with a subcutaneous pretreatment of 2% AgNO3, all mice from both strains that were injected with crude or purified murine AA amyloid developed AA amyloidosis. However, the amyloid index, which was determined by the intensity of AA amyloid deposition, was significantly higher in IL-1raKO mice than in BALB/c mice. When IL-1raKO and BALB/c mice were injected with crude or purified bovine AA amyloid together with the pretreatment, 83% (5/6 cases) and 38% (3/8 cases) of IL-1raKO mice and 17% (1/6 cases) and 0% (0/6 cases) of BALB/c mice, respectively, developed AA amyloidosis. Similarly, when IL-1raKO and BALB/c mice were injected with crude or purified feline AA amyloid, 33% (2/6 cases) and 88% (7/8 cases) of IL-1raKO mice and 0% (0/6 cases) and 29% (2/6 cases) of BALB/c mice, respectively, developed AA amyloidosis. These results indicated that IL-1raKO mice are a useful animal model for investigating AA amyloidogenesis. © The Author(s) 2014.

  16. Correlation between Wavelength Dispersive X-ray Fluorescence (WDXRF) analysis of hardened concrete for chlorides vs. Atomic Absorption (AA) analysis in accordance with AASHTO T- 260; sampling and testing for chloride ion in concrete and concrete raw mater

    DOT National Transportation Integrated Search

    2014-04-01

    A correlation between Wavelength Dispersive X-ray Fluorescence(WDXRF) analysis of Hardened : Concrete for Chlorides and Atomic Absorption (AA) analysis (current method AASHTO T-260, procedure B) has been : found and a new method of analysis has been ...

  17. Evolutionary Limitation and Opportunities for Developing tRNA Synthetase Inhibitors with 5-Binding-Mode Classification

    PubMed Central

    Fang, Pengfei; Guo, Min

    2015-01-01

    Aminoacyl-tRNA synthetases (aaRSs) are enzymes that catalyze the transfer of amino acids to their cognate tRNAs as building blocks for translation. Each of the aaRS families plays a pivotal role in protein biosynthesis and is indispensable for cell growth and survival. In addition, aaRSs in higher species have evolved important non-translational functions. These translational and non-translational functions of aaRS are attractive for developing antibacterial, antifungal, and antiparasitic agents and for treating other human diseases. The interplay between amino acids, tRNA, ATP, EF-Tu and non-canonical binding partners, had shaped each family with distinct pattern of key sites for regulation, with characters varying among species across the path of evolution. These sporadic variations in the aaRSs offer great opportunity to target these essential enzymes for therapy. Up to this day, growing numbers of aaRS inhibitors have been discovered and developed. Here, we summarize the latest developments and structural studies of aaRS inhibitors, and classify them with distinct binding modes into five categories. PMID:26670257

  18. Launcher Roadmap for the CrVI Substitution of Surface Treatments. Screening of Trivalent-Chromium Conversion Solutions and First Promising Results for Repair Applications on Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Debout, Vincent; Pettier, Sophie

    2014-06-01

    Airbus Defence and Space, Space System is involved in a global roadmap for launchers in order to substitute hexavalent chromium (CrVI) and Cadmium in the current surface treatments on metallic structures.Within this framework, a screening of trivalent chromium (CrIII) conversion solutions for touch-up applications has been carried out since this step is crucial to perform local application or to repair minor damages on launcher structures but it leads to higher risks of exposure for the workers.Three commercial CrIII conversion solutions have been evaluated on high performance aluminum alloys such as AA2024 T3 and AA7175 T7351 that are often used as structural materials.This preliminary investigation highlights the effect of surface preparation, rinsing and conversion process on the final corrosion performance of conversion coatings (CCs). The results are also discussed in terms of visual aspect and adhesion with new Cr-free primers.Two operating sets of parameters are identified with promising results that represent the first steps towards the development of a new Cr-free touch-up process.

  19. Effects of Tibetan Music on Neuroendocrine and Autonomic Functions in Patients Waiting for Surgery: A Randomized, Controlled Study.

    PubMed

    Cotoia, Antonella; Dibello, Floriana; Moscatelli, Fiorenzo; Sciusco, Alberto; Polito, Pietro; Modolo, Alberto; Gallo, Crescenzio; Cibelli, Giuseppe; Cinnella, Gilda

    2018-01-01

    The aim of this study was to investigate the effects of listening to Tibetan music on anxiety and endocrine, autonomic, cognitive responses in patients waiting for urologic surgery. Sixty patients waiting for surgery were enrolled to the study. They were randomized in music (M) and control (C) groups. The M group listened to a low-frequency Tibetan music for 30 min (T 0 -T 30 ) through headphones, and the C group wore headphones with no sound. The State Trait Anxiety Inventory Questionnaire (STAI) Y-1 was administered at T 0 and T 30 . Normalized low (LFnu) and high frequencies (HFnu) of heart rate variability, LF/HF ratio, and galvanic skin response (GRS) data were analyzed at T 0 , T 10 , T 20 , T 30 , and T 35 . The salivary α -amylase (sAA) samples were collected at T 0 , T 35 , and T 45 . In the M group, the STAI Y-1 score decreased at T 30 versus baseline ( p < 0.001), sAA levels decreased at T 35 versus T 0 ( p =0.004), and GSR remained unchanged. In the C group, the STAI Y-1 score remained unchanged, sAA level increased at T 35 versus T 0 ( p < 0.001), and GSR slightly increased at T 35 versus baseline ( p =0.359). LFnu was lower, and HFnu was significantly higher (T 10 -T 30 ) in M versus C group. Mean LF/HF ratio slightly reduced in the M group. Our results suggest that preoperative listening to relaxing Tibetan music might be a useful strategy to manage preoperative anxiety.

  20. Roles of tRNA in cell wall biosynthesis

    PubMed Central

    Dare, Kiley; Ibba, Michael

    2013-01-01

    Recent research into various aspects of bacterial metabolism such as cell wall and antibiotic synthesis, degradation pathways, cellular stress, and amino acid biosynthesis has elucidated roles of aminoacyl-transfer ribonucleic acid (aa-tRNA) outside of translation. Although the two enzyme families responsible for cell wall modifications, aminoacyl-phosphatidylglycerol synthases (aaPGSs) and Fem, were discovered some time ago, they have recently become of intense interest for their roles in the antimicrobial resistance of pathogenic microorganisms. The addition of positively charged amino acids to phosphatidylglycerol (PG) by aaPGSs neutralizes the lipid bilayer making the bacteria less susceptible to positively charged antimicrobial agents. Fem transferases utilize aa-tRNA to form peptide bridges that link strands of peptidoglycan. These bridges vary among the bacterial species in which they are present and play a role in resistance to antibiotics that target the cell wall. Additionally, the formation of truncated peptides results in shorter peptide bridges and loss of branched linkages which makes bacteria more susceptible to antimicrobials. A greater understanding of the structure and substrate specificity of this diverse enzymatic family is necessary to aid current efforts in designing potential bactericidal agents. These two enzyme families are linked only by the substrate with which they modify the cell wall, aa-tRNA; their structure, cell wall modification processes and the physiological changes they impart on the bacterium differ greatly. PMID:22262511

  1. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  2. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  3. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  4. 40 CFR Table Aa-1 to Subpart Aa of... - Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Kraft Pulping Liquor Emissions Factors for Biomass-Based CO2, CH4, and N2O AA Table AA-1 to Subpart AA of Part 98 Protection of Environment... Paper Manufacturing Pt. 98, Subpt. AA, Table AA-1 Table AA-1 to Subpart AA of Part 98—Kraft Pulping...

  5. Corrosion Fatigue of Anodized Aluminum 7075-T73 in Salt Ladened Humid Air.

    DTIC Science & Technology

    1981-01-01

    relative humidity and coating thickness on the fatigue of anodized 2024-T351 aluminum in reversed torsion . They also found no effect of coating ... fatigue resistance. Most of the previous corrosion fatigue work has been on the effect of relative humidity on the fatigue life of coated aluminum ...alloys. Eeles and 1hurston Iwere some of the early investigators

  6. Trends in diabetes incidence from 1992 to 2015 and projections for 2024: A Portuguese General Practitioner's Network study.

    PubMed

    de Sousa-Uva, Mafalda; Antunes, L; Nunes, B; Rodrigues, A P; Simões, J A; Ribeiro, R T; Boavida, J M; Matias-Dias, C

    2016-10-01

    Diabetes is known as a major cause of morbidity and mortality worldwide. Portugal is known as the European country with the highest prevalence of this disease. While diabetes prevalence data is updated annually in Portugal, the General Practitioner's (GP) Sentinel Network represents the only data source on diabetes incidence. This study describes the trends in Diabetes incidence, between 1992 and 2015, and estimate projections for the future incidence rates in Portugal until 2024. An ecological time-series study was conducted using data from GP Sentinel Network between 1992 and 2015. Family doctors reported all new cases of Diabetes in their patients' lists. Annual trends were estimated through Poisson regression models as well as the future incidence rates (until 2024), sex and age group stratified. Incidence rate projections were adjusted to the distribution of the resident Portuguese population given Statistics Portugal projections. The average increase in Diabetes incidence rate was in total 4.29% (CI95% 3.80-4.80) per year under study. Until 1998-2000, the annual incidence rate was higher in women, and from 1998-2000 to 2013-2015 turn out to be higher in men. The incidence rate projected for 2022-2024 was 972.77/10(5) inhabitants in total, and 846.74/10(5) and 1114.42/10(5), respectively, in women and men. This is the first study in Portugal to estimate diabetes incidence rate projections. The disturbing reported projections seem realistic if things continue as in the past. Actually, effective public health policies will need to be undertaken to minimize this alarming future scenario. Copyright © 2016 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.

  7. High-Speed Friction Stir Welding of AA7075-T6 Sheet: Microstructure, Mechanical Properties, Micro-texture, and Thermal History

    NASA Astrophysics Data System (ADS)

    Zhang, Jingyi; Upadhyay, Piyush; Hovanski, Yuri; Field, David P.

    2018-01-01

    Friction stir welding (FSW) is a cost-effective and high-quality joining process for aluminum alloys (especially heat-treatable alloys) that is historically operated at lower joining speeds (up to hundreds of millimeters per minute). In this study, we present a microstructural analysis of friction stir welded AA7075-T6 blanks with high welding speeds up to 3 M/min. Textures, microstructures, mechanical properties, and weld quality are analyzed using TEM, EBSD, metallographic imaging, and Vickers hardness. The higher welding speed results in narrower, stronger heat-affected zones (HAZs) and also higher hardness in the nugget zones. The material flow direction in the nugget zone is found to be leaning towards the welding direction as the welding speed increases. Results are coupled with welding parameters and thermal history to aid in the understanding of the complex material flow and texture gradients within the welds in an effort to optimize welding parameters for high-speed processing.

  8. Obesity is a significant susceptibility factor for idiopathic AA amyloidosis.

    PubMed

    Blank, Norbert; Hegenbart, Ute; Dietrich, Sascha; Brune, Maik; Beimler, Jörg; Röcken, Christoph; Müller-Tidow, Carsten; Lorenz, Hanns-Martin; Schönland, Stefan O

    2018-03-01

    To investigate obesity as susceptibility factor in patients with idiopathic AA amyloidosis. Clinical, biochemical and genetic data were obtained from 146 patients with AA amyloidosis. Control groups comprised 40 patients with long-standing inflammatory diseases without AA amyloidosis and 56 controls without any inflammatory disease. Patients with AA amyloidosis had either familial Mediterranean fever (FMF) or long-standing rheumatic diseases as underlying inflammatory disease (n = 111, median age 46 years). However, in a significant proportion of patients with AA amyloidosis no primary disease was identified (idiopathic AA; n = 37, median age 60 years). Patients with idiopathic AA amyloidosis were more obese and older than patients with AA amyloidosis secondary to FMF or rheumatic diseases. Serum leptin levels correlated with the body mass index (BMI) in all types of AA amyloidosis. Elevated leptin levels of more than 30 µg/l were detected in 18% of FMF/rheumatic + AA amyloidosis and in 40% of patients with idiopathic AA amyloidosis (p = .018). Finally, the SAA1 polymorphism was confirmed as a susceptibility factor for AA amyloidosis irrespective of the type of the disease. Obesity, age and the SAA1 polymorphism are susceptibility factors for idiopathic AA amyloidosis. Recent advances in treatment of FMF and rheumatic disorders will decrease the incidence of AA amyloidosis due to these diseases. Idiopathic AA, however, might be an emerging problem in the ageing and increasingly obese population.

  9. Toward the Clonotype Analysis of Alopecia Areata-Specific, Intralesional Human CD8+ T Lymphocytes.

    PubMed

    Bertolini, Marta; Uchida, Youhei; Paus, Ralf

    2015-11-01

    Alopecia areata (AA) is an organ-restricted autoimmune disease that mainly affects the hair follicle (HF). Several findings support a key primary effector role of CD8+ T cells in the disease pathogenesis. Autoreactive CD8+ T cells are not only present in the characteristic peribulbar inflammatory cell infiltrate of lesional AA HFs but are also found to be infiltrating in lesional HF epithelium where they are thought to recognize major histocompatibility complex class I-presented (auto-)antigens. However, the latter still remain unidentified. Therefore, one key aim in AA research is to identify the clonotypes of autoaggressive, intralesional CD8+ T cells. Therapeutically, this is important (a) so that these lymphocytes can be selectively eliminated or inhibited, (b) to identify the-as yet elusive-key (auto-)antigens in AA, and/or (c) to induce peripheral tolerance against the latter. Therefore, we have recently embarked on a National Alopecia Areata Foundation-supported project that attempts to isolate disease-specific, intralesional CD8+ T cells from AA skin in order to determine their TCR clonotype, using two complementary strategies. The first method is based on the enzymatic skin digestion from lesional AA skin, followed by either MACS technology and single-cell picking or FACS cell sorting, while the second method on laser microdissection. The identification of disease-specific TCRs can serve as a basis for specific AA immunotherapy along the lines sketched above and may possibly also provide prognostic biomarkers. If successful, this research strategy promises to permit, at long last, the causal therapy of AA.

  10. AAS Career Services

    NASA Astrophysics Data System (ADS)

    Marvel, Kevin B.

    2012-08-01

    The American Astronomical Society provides substantial programs in the area of Career Services.Motivated by the Society's mission to enhance and share humanity's understanding of the Universe, the AAS provides a central resource for advertising positions, interviewing opportunities at its annual winter meeting and information, workshops and networks to enable astronomers to find employment.The programs of the Society in this area are overseen by an active committee on employment and the AAS Council itself.Additional resources that help characterize the field, its growth and facts about employment such as salaries and type of jobs available are regularly summarized and reported on by the American Institute of Physics.

  11. Very large array and green bank telescope observations of Orion B (NGC 2024, W12): photodissociation region properties and magnetic field

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Roshi, D. Anish; Goss, W. M.; Jeyakumar, S., E-mail: aroshi@nrao.edu, E-mail: mgoss@nrao.edu, E-mail: sjk@astro.ugto.mx

    We present images of C110α and H110α radio recombination line (RRL) emission at 4.8 GHz and images of H166α, C166α, and X166α RRL emission at 1.4 GHz, observed toward the star-forming region NGC 2024. The 1.4 GHz image with angular resolution ∼70'' is obtained using Very Large Array (VLA) data. The 4.8 GHz image with angular resolution ∼17'' is obtained by combining VLA and Green Bank Telescope data in order to add the short and zero spacing data in the uv plane. These images reveal that the spatial distributions of C110α line emission is confined to the southern rim ofmore » the H II region close to the ionization front whereas the C166α line emission is extended in the north-south direction across the H II region. The LSR velocity of the C110α line is 10.3 km s{sup –1} similar to that of lines observed from molecular material located at the far side of the H II region. This similarity suggests that the photodissociation region (PDR) responsible for C110α line emission is at the far side of the H II region. The LSR velocity of C166α is 8.8 km s{sup –1}. This velocity is comparable with the velocity of molecular absorption lines observed from the foreground gas, suggesting that the PDR is at the near side of the H II region. Non-LTE models for carbon line-forming regions are presented. Typical properties of the foreground PDR are T {sub PDR} ∼ 100 K, n{sub e}{sup PDR}∼5 cm{sup –3}, n {sub H} ∼ 1.7 × 10{sup 4} cm{sup –3}, and path length l ∼ 0.06 pc, and those of the far side PDR are T {sub PDR} ∼ 200 K, n{sub e}{sup PDR}∼ 50 cm{sup –3}, n {sub H} ∼ 1.7 × 10{sup 5} cm{sup –3}, and l ∼ 0.03 pc. Our modeling indicates that the far side PDR is located within the H II region. We estimate the magnetic field strength in the foreground PDR to be 60 μG and that in the far side PDR to be 220 μG. Our field estimates compare well with the values obtained from OH Zeeman observations toward NGC 2024. The H166α spectrum shows

  12. 40 CFR 35.4215 - What if my group can't find an adequate number of potential sources for a technical advisor or...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... number of potential sources for a technical advisor or other contractor? 35.4215 Section 35.4215... ASSISTANCE Grants for Technical Assistance Procuring A Technical Advisor Or Other Contractor with Tag Funds § 35.4215 What if my group can't find an adequate number of potential sources for a technical advisor...

  13. The -2T/C polymorphism in the adrenocorticotropin receptor gene affects stress perception of patients with alopecia areata.

    PubMed

    Guo, Hong-Wei; Guo, Hong; Li, Ke-Shen; Wu, Jiang; Yang, Shao-Yan; Liu, Bao-Heng; Hao, Fei; Bai, Yun

    2013-04-01

    Altered hypothalamic-pituitary-adrenal (HPA) axis response involved in the pathogenesis of stress-associated alopecia areata (AA) has been reported. A novel polymorphism -2T>C of the adrenocorticotropin receptor (ACTHR) can result in an insufficient HPA response to stress; therefore, the functional polymorphism may underlie a role in stress-associated AA. To investigate the relationship between psychosocial factors and the risk of developing AA and to detect the association between the -2T>C polymorphism of ACTHR and AA. Stressful situations were evaluated using Holmes and Rahe's social readjustment rating scale. The ACTHR -2T>C polymorphism was examined in 263 patients with AA and 241 controls. Significant elevation of psychological stress experienced by some patients with AA compared with controls (Z = 6.628, P < 0.01). The frequency of the ACTHR C allele showed a significant difference between patients with AA and controls (P = 0.004). Allele C is the risk allele with a dominant model as the -2C allele occurred more often in patients with AA (P = 0.001). There were significant differences between patients with AA with a severe stress attack versus patients with AA with no obvious stress (P < 0.001), whereas the genotype frequencies were not correlated with the type, duration of disease, and age at onset. Notably, the C allele carrier was significantly associated with stress risk in both AA and controls (P = 0.002, OR = 1.576, 95% CI: 1.148-2.162; P = 0.042, OR = 1.529, 95% CI: 1.022-2.288). These findings suggest AA in some patients may be associated with stress. The ACTHR gene -2T>C variant may be one important factor that influences stress perception of patients with AA. © 2012 The International Society of Dermatology.

  14. Facile Synthesis of Smart Nanocontainers as Key Components for Construction of Self-Healing Coating with Superhydrophobic Surfaces.

    PubMed

    Liang, Yi; Wang, MingDong; Wang, Cheng; Feng, Jing; Li, JianSheng; Wang, LianJun; Fu, JiaJun

    2016-12-01

    SiO2-imidazoline nanocomposites (SiO2-IMI) owning high loading capacity of corrosion inhibitor, 1-hexadecyl-3-methylimidazolium bromide (HMID), and a special acid/alkali dual-stimuli-accelerated release property have been synthesized via a one-step modified Stöber method. SiO2-IMI were uniformly distributed into the hydrophobic SiO2 sol to construct "host"-"guest" feedback active coating with a superhydrophobic surface (SiO2-IMI@SHSC) on aluminium alloy, AA2024, by dip-coating technique. SiO2-IMI as "guest" components have good compatibility with "host" sol-gel coating, and more importantly, once localized corrosion occurs on the surface of AA2024, SiO2-IMI can simultaneously respond to the increase in environmental pH around corrosive micro-cathodic regions and decrease in pH near micro-anodic regions, promptly releasing HMID to form a compact molecular film on the damaged surface, inhibiting corrosion spread and executing a self-healing function. The scanning vibrating electrode technique (SVET) was applied to illustrate the suppression process of cathodic/anodic corrosion activities. Furthermore, benefiting from the superhydrophobic surface, SiO2-IMI@SHSC remained its protective ability after immersion in 0.5 M NaCl solution for 35 days, which is far superior to the conventional sol-gel coating with the same coating thickness. The facile fabrication method of SiO2-IMI simplifies the construction procedure of SiO2-IMI@SHSC, which have great potential to replace non-environmental chromate conversion coatings for practical use.

  15. MCT1 A1470T: a novel polymorphism for sprint performance?

    PubMed

    Sawczuk, Marek; Banting, Lauren K; Cięszczyk, Paweł; Maciejewska-Karłowska, Agnieszka; Zarębska, Aleksandra; Leońska-Duniec, Agata; Jastrzębski, Zbigniew; Bishop, David J; Eynon, Nir

    2015-01-01

    The A1470T polymorphism (rs1049434) in the monocarboxylate (lactate/pyruvate) transporter 1 gene (MCT1) has been suggested to influence athletic performance in the general population. We compared genotype distributions and allele frequencies of the MCT1 gene A1470T polymorphism between endurance athletes, sprint/power athletes and matched controls. We also examined the association between the MCT1 A1470T and the athletes' competition level ('elite' and 'national' level). The study involved endurance athletes (n=112), sprint/power athletes (n=100), and unrelated sedentary controls (n=621), all Caucasians. Genomic DNA was extracted from buccal epithelium using a standard protocol. We conducted Fisher's exact tests and multinomial logistic regression analyses to assess the association between MCT1 genotype and athletic status/competition level. Sprint/power athletes were more likely than controls to possess the minor T allele (TT genotype compared to the AA [p<0.001]; TT or AT compared to the AA [p=0.007]; TT compared to both AA and AT genotypes [p<0.001]). Likewise, sprint/power athletes were more likely than endurance athletes to have the TT genotype compared to the AA (p=0.029) and the TT compared to both AA and AT genotypes (p=0.027). Furthermore, elite sprint/power athletes were more likely than national-level athletes to have the TT genotype compared to the AA (p=0.044), and more likely to have the TT genotype compared to both AA and AT genotypes (recessive model) (p=0.045). The MCT1 TT genotype is associated with elite sprint/power athletic status. Future studies are encouraged to replicate these findings in other elite athlete cohorts. Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  16. Selective Laser Treatment on Cold-Sprayed Titanium Coatings: Numerical Modeling and Experimental Analysis

    NASA Astrophysics Data System (ADS)

    Carlone, Pierpaolo; Astarita, Antonello; Rubino, Felice; Pasquino, Nicola; Aprea, Paolo

    2016-12-01

    In this paper, a selective laser post-deposition on pure grade II titanium coatings, cold-sprayed on AA2024-T3 sheets, was experimentally and numerically investigated. Morphological features, microstructure, and chemical composition of the treated zone were assessed by means of optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry. Microhardness measurements were also carried out to evaluate the mechanical properties of the coating. A numerical model of the laser treatment was implemented and solved to simulate the process and discuss the experimental outcomes. Obtained results highlighted the key role played by heat input and dimensional features on the effectiveness of the treatment.

  17. 40 CFR 35.4055 - What if my group can't come up with the “matching funds?”

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false What if my group can't come up with the... Responsibilities As A Tag Recipient § 35.4055 What if my group can't come up with the “matching funds?” (a) EPA may... financial hardship to your group (for example, your local economy is depressed and coming up with in-kind...

  18. 40 CFR 35.4055 - What if my group can't come up with the “matching funds?”

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false What if my group can't come up with the... Responsibilities As A Tag Recipient § 35.4055 What if my group can't come up with the “matching funds?” (a) EPA may... financial hardship to your group (for example, your local economy is depressed and coming up with in-kind...

  19. 40 CFR 35.4055 - What if my group can't come up with the “matching funds?”

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false What if my group can't come up with the... Responsibilities As A Tag Recipient § 35.4055 What if my group can't come up with the “matching funds?” (a) EPA may... financial hardship to your group (for example, your local economy is depressed and coming up with in-kind...

  20. 40 CFR 35.4055 - What if my group can't come up with the “matching funds?”

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false What if my group can't come up with the... Responsibilities As A Tag Recipient § 35.4055 What if my group can't come up with the “matching funds?” (a) EPA may... financial hardship to your group (for example, your local economy is depressed and coming up with in-kind...

  1. 40 CFR 35.4055 - What if my group can't come up with the “matching funds?”

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false What if my group can't come up with the... Responsibilities As A Tag Recipient § 35.4055 What if my group can't come up with the “matching funds?” (a) EPA may... financial hardship to your group (for example, your local economy is depressed and coming up with in-kind...

  2. Mechanical properties of dissimilar metal joints composed of DP 980 steel and AA 7075-T6

    DOE PAGES

    Squires, Lile; Lim, Yong Chae; Miles, Michael; ...

    2015-03-18

    In this study, a solid state joining process, called friction bit joining, was used to spot weld aluminium alloy 7075-T6 to dual phase 980 steel. Lap shear failure loads for specimens without adhesive averaged ~10kN, while cross-tension specimens averaged 2·8 kN. Addition of adhesive with a thickness up to 500 μm provided a gain of ~50% to lap shear failure loads, while a much thinner layer of adhesive increased cross-tension failure loads by 20%. Microstructures of the welds were martensitic, but the hardness of the joining bit portion was greater than that of the DP 980, owing to its highermore » alloy content. Softening in the heat affected zone of a welded joint appeared to be relatively small, though it was enough to cause nugget pullout failures in some lap shear tension specimens. Finally, other failures in lap shear tension were interfacial, while all of the failures in cross-tension were interfacial.« less

  3. Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

    NASA Astrophysics Data System (ADS)

    Okafor, A. C.; Natarajan, S.

    2007-03-01

    Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.

  4. Proteolysis of serum amyloid A and AA amyloid proteins by cysteine proteases: cathepsin B generates AA amyloid proteins and cathepsin L may prevent their formation

    PubMed Central

    Rocken, C; Menard, R; Buhling, F; Vockler, S; Raynes, J; Stix, B; Kruger, S; Roessner, A; Kahne, T

    2005-01-01

    Background: AA amyloidosis develops in patients with chronic inflammatory diseases. The AA amyloid proteins are proteolytic fragments obtained from serum amyloid A (SAA). Previous studies have provided evidence that endosomes or lysosomes might be involved in the processing of SAA, and contribute to the pathology of AA amyloidosis. Objective: To investigate the anatomical distribution of cathepsin (Cath) B and CathL in AA amyloidosis and their ability to process SAA and AA amyloid proteins. Methods and results: CathB and CathL were found immunohistochemically in every patient with AA amyloidosis and displayed a spatial relationship with amyloid in all the cases studied. Both degraded SAA and AA amyloid proteins in vitro. With the help of mass spectrometry 27 fragments were identified after incubation of SAA with CathB, nine of which resembled AA amyloid proteins, and seven fragments after incubation with CathL. CathL did not generate AA amyloid-like peptides. When native human AA amyloid proteins were used as a substrate 26 fragments were identified after incubation with CathB and 18 after incubation with CathL. Conclusion: The two most abundant and ubiquitously expressed lysosomal proteases can cleave SAA and AA amyloid proteins. CathB generates nine AA amyloid-like proteins by its carboxypeptidase activity, whereas CathL may prevent the formation of AA amyloid proteins by endoproteolytic activity within the N-terminal region of SAA. This is particularly interesting, because AA amyloidosis is a systemic disease affecting many organs and tissue types, almost all of which express CathB and CathL. PMID:15897303

  5. A green route to methyl acrylate and acrylic acid by an aldol condensation reaction over H-ZSM-35 zeolite catalysts.

    PubMed

    Ma, Zhanling; Ma, Xiangang; Liu, Hongchao; He, Yanli; Zhu, Wenliang; Guo, Xinwen; Liu, Zhongmin

    2017-08-10

    A one-step aldol condensation reaction to produce MA and AA is a green and promising strategy. Here, the aldol condensation reaction was first conducted with DMM and MAc over different types of zeolite catalysts. The H-ZSM-35 zeolite demonstrates excellent catalytic performance with a DMM conversion of 100% and a MA + AA selectivity of up to 86.2% and superior regeneration ability, with great potential for industrial operation.

  6. AAS Oral History Project

    NASA Astrophysics Data System (ADS)

    Buxner, Sanlyn; Holbrook, Jarita; AAS Oral History Team

    2016-06-01

    Now in its fourth year, the AAS Oral History Project has interviewed over 80 astronomers from all over the world. Led by the AAS Historical Astronomy Division (HAD) and partially funded by the American Institute of Physics Niels Bohr Library and ongoing support from the AAS, volunteers have collected oral histories from astronomers at professional meetings starting in 2015, including AAS, DPS, and the IAU general assembly. Each interview lasts one and a half to two hours and focuses on interviewees’ personal and professional lives. Questions include those about one’s family, childhood, strong influences on one’s scientific career, career path, successes and challenges, perspectives on how astronomy is changing as a field, and advice to the next generation. Each interview is audio recorded and transcribed, the content of which is checked with each interviewee. Once complete, interview transcripts are posted online as part of a larger oral history library at https://www.aip.org/history-programs/niels-bohr-library/oral-histories. Future analysis will reveal a rich story of astronomers and will help the community address issues of diversity, controversies, and the changing landscape of science. We are still recruiting individuals to be interviewed from all stages of career from undergraduate students to retired and emeritus astronomers. Contact Jarita Holbrook to schedule an interview or to find out more information about the project (astroholbrook@gmail.com). Also, contact Jarita Holbrook if you would like to become an interviewer for the project.

  7. Methods for Kinetic and Thermodynamic Analysis of Aminoacyl-tRNA Synthetases

    PubMed Central

    Francklyn, Christopher S.; First, Eric A.; Perona, John J.; Hou, Ya-Ming

    2008-01-01

    The accuracy of protein synthesis relies on the ability of aminoacyl-tRNA synthetases (aaRSs) to discriminate among true and near cognate substrates. To date, analysis of aaRSs function, including identification of residues of aaRS participating in amino acid and tRNA discrimination, has largely relied on the steady state kinetic pyrophosphate exchange and aminoacylation assays. Pre-steady state kinetic studies investigating a more limited set of aaRS systems have also been undertaken to assess the energetic contributions of individual enzyme-substrate interactions, particularly in the adenylation half reaction. More recently, a renewed interest in the use of rapid kinetics approaches for aaRSs has led to their application to several new aaRS systems, resulting in the identification of mechanistic differences that distinguish the two structurally distinct aaRS classes. Here, we review the techniques for thermodynamic and kinetic analysis of aaRS function. Following a brief survey of methods for the preparation of materials and for steady state kinetic analysis, this review will describe pre-steady state kinetic methods employing rapid quench and stopped-flow fluorescence for analysis of the activation and aminoacyl transfer reactions. Application of these methods to any aaRS system allows the investigator to derive detailed kinetic mechanisms for the activation and aminoacyl transfer reactions, permitting issues of substrate specificity, stereochemical mechanism, and inhibitor interaction to be addressed in a rigorous and quantitative fashion. PMID:18241792

  8. CP-25 attenuates the inflammatory response of fibroblast-like synoviocytes co-cultured with BAFF-activated CD4(+) T cells.

    PubMed

    Jia, Xiaoyi; Wei, Fang; Sun, Xiaojing; Chang, Yan; Xu, Shu; Yang, Xuezhi; Wang, Chun; Wei, Wei

    2016-08-02

    Total glucosides of paeony (TGP) is the first anti-inflammatory immune regulatory drug approved for the treatment of rheumatoid arthritis in China. A novel compound, paeoniflorin-6'-O-benzene sulfonate (code CP-25), comes from the structural modification of paeoniflorin (Pae), which is the effective active ingredient of TGP. The aim of the present study is to investigate the effect of CP-25 on adjuvant arthritis (AA) fibroblast-like synoviocytes (FLS) co-cultured with BAFF-activated CD4(+) T cells and the expression of BAFF-R in CD4(+) T cells. The mRNA expression of BAFF and its receptors was assessed by qPCR. The expression of BAFF receptors in CD4(+) T cells was analyzed by flow cytometry. The effect of CP-25 on AA rats was evaluated by their joint histopathology. The cell culture growth of thymocytes and FLS was detected by cell counting kit (CCK-8). The concentrations of IL-1β, TNF-α, and IL-6 were measured by Enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of BAFF and BAFF-R were enhanced in the mesenteric lymph nodes of AA rats, TACI expression was reduced, and BCMA had no change. The expression of BAFF-R in CD4(+) T cells was also enhanced. CP-25 alleviated the joint histopathology and decreased the expression of BAFF-R in CD4(+) T cells from AA rats in vivo. In vitro, CP-25 inhibited the abnormal cell culture growth of BAFF-stimulated thymocytes and FLS. In the co-culture system, IL-1β, IL-6 and TNF-α production was enhanced by FLS co-cultured with BAFF-activated CD4(+) T cells. Moreover, BAFF-stimulated CD4(+) T cells promoted the cell culture growth of FLS. The addition of CP-25 decreased the expression of BAFF-R in CD4(+) T cells and inhibited the cell culture growth and cytokine secretion ability of FLS co-cultured with BAFF-activated CD4(+) T cells. The present study indicates that CP-25 may repress the cell culture growth and cytokine secretion ability of FLS, and its inhibitory effects might be associated with its ability

  9. 35% Good Outcome Rate in IV-tPA treated Patients with CTA Confirmed Severe Anterior Circulation Occlusive Stroke

    PubMed Central

    González, R. Gilberto; Furie, Karen L.; Goldmacher, Gregory V.; Smith, Wade S.; Kamalian, Shervin; Payabvash, Seyedmehdi; Harris, Gordon J.; Halpern, Elkan F.; Koroshetz, Walter J.; Camargo, Erica C. S.; Dillon, William P.; Lev, Michael H.

    2015-01-01

    BACKGROUND AND PURPOSE To determine the effect of IV-tPA on outcomes in patients with severe major anterior circulation ischemic stroke. METHODS Prospectively, 649 acute stroke patients had admission NIH stroke scale scores (NIHSS), non-contrast CT, CT angiography (CTA), and 6-month outcome assessed using modified Rankin scale (mRS). IV-tPA treatment decisions were made prior to CTA, at the time of non-contrast CT scanning, as per routine clinical protocol. Severe symptoms were defined as NIHSS>10. Poor outcome was defined as mRS>2. Major occlusions were identified on CTA. Univariate and multivariate stepwise-forward logistic regression analyses of the full cohort were performed. RESULTS Of 649 patients, 188 (29%) presented with NIHSS>10, and 64/188 (34%) of these received IV-tPA. Admission NIHSS, large artery occlusion, and IV-tPA all independently predicted good outcomes, however a significant interaction existed between IV-tPA and occlusion (p<0.001). Of NIHSS>10 patients with anterior circulation occlusion, twice the percentage had good outcomes if they received IV-tPA (17/49, 35%), than if they did not (13/77, 17%; p=0.031). The “number needed to treat” was 7 (95% CI = 3–60). CONCLUSIONS IV-tPA treatment resulted in significantly more good outcomes in severely symptomatic stroke patients with major anterior circulation occlusions. The 35% good outcome rate was similar to rates found in endovascular therapy trials. Vascular imaging may help in patient selection and stratification for trials of IV-thrombolytic and endovascular therapies. PMID:24003051

  10. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M. P.; Hihn, J. Y.

    2015-11-01

    Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  11. Effect of Scandium on the Interaction of Concurrent Precipitation and Recrystallization in Commercial AA3003 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Tu, Yiyou; Qian, Huan; Zhou, Xuefeng; Jiang, Jianqing

    2014-04-01

    In the current study, the effect of Sc addition on the interaction of concurrent precipitation and recrystallization in commercial AA3003 aluminum alloy was investigated using optical microscopy, scanning electron microscopy, and transmission electron microscopy. In case of AA3003 alloy, which was cold rolled to a true strain of 2.20 and heated at a heating rate of 150 K/s, the onset of precipitation and ending of recrystallization are signified by the critical temperature, T C ~740 K (467 °C). There is a change in the shape of the recrystallized grains from pancake-like to equiaxed shape, as the annealing temperature increases greater than T C. In case of AA3003 alloy microalloyed with 0.4 wt pct of Sc, the high no. density precipitation of coherent Al3Sc precipitates always occurs before recrystallization because of the small nucleation barrier and high rate of decomposition. This leads to extremely coarse pancake-like recrystallization grains with high fraction of low-angle grain boundaries in the entire annealing temperature range, even at a high brazing temperature of 883 K (610 °C).

  12. Analysis of the flow property of aluminum alloy AA6016 based on the fracture morphology using the hydroforming technology

    NASA Astrophysics Data System (ADS)

    Lang, Lihui; Zhang, Quanda; Sun, Zhiying; Wang, Yao

    2017-09-01

    In this paper, the hydraulic bulging experiments were respectively carried out using AA6016-T4 aluminum alloy and AA6016-O aluminum alloy, and the deformation properties and fracture mechanism of aluminum alloy under the conditions of thermal and hydraulic were analyzed. Firstly, the aluminum alloy AA6016 was dealt with two kinds of heat treatment systems such as solid solution heat treatment adding natural ageing and full annealing, then the aluminum alloy such as AA6016-T4 and AA6016-O were obtained. In the same working environment, the two kinds of materials were used in the process of hydraulic bulging experiments, according to the observation and measurement of the deformation sizes of grid circles and material thicknesses near the fracture region, the flow properties and development trend of fracture defect of the materials were analyzed comprehensively from the perspective of qualitative analysis and quantitative analysis; Secondly, the two kinds of materials were sampled in different regions of the fracture area and the microstructure morphology of the fracture was observed by the scanning electron microscope (SEM). The influence laws of the heat treatment systems on the fracture defect of the aluminum alloy under the condition of the liquid pressure were studied preliminarily by observing the distribution characteristics of the fracture microstructure morphology of dimple. At the same time, the experimental research on the ordinary stamping forming process of AA6016-O was carried out and the influence law of different forming process on the fracture defect of the aluminum alloy material was studied by observing the distribution of the fracture microstructure morphology; Finally, the development process of the fracture defect of aluminum alloy sheet was described theoretically from the view of the stress state.

  13. Rating AAs.

    ERIC Educational Resources Information Center

    Carter, Susan J.

    2001-01-01

    Why alternative investments? In a word: performance. Many higher education endowment and foundation managers are making increasing commitments to alternative investments, or AAs, in order to obtain higher returns and broader diversification for their investment portfolios than public securities instruments can usually provide. Learn how to handle…

  14. Investigation of Fatigue Crack-Growth Resistance of Aluminum Alloys under Spectrum Loading.

    DTIC Science & Technology

    1983-04-01

    Effects on Fatigue Crack Progation in 2024 -T3 Aluminum Alloy ," Eng. Frac. Mech, Vol...results ("a" from 6 to 13 mm) can be made (Figure 20a): 1. The 2XXX alloys 2020-T651, 2324-T39, and 2024 - T351 had longer spectrum fatigue lives than the...strength and spectrum life exists at all three maximum peak stress levels for the 2024 alloy , with the lower yield strength T351 condition having

  15. Analysis of Widespread Fatigue Damage in Aerospace Structures

    DTIC Science & Technology

    1999-02-01

    Fatigue in 2024 - T351 Aluminum Alloy ," Wear, 221(1), pp 24-36 (1998). 20. T.N. Farris, M.P. Szolwinski and G...Fretting Fatigue in 2024 - T351 Aluminum Alloy ," Wear, 221(1), pp 24-36 (1998). Hsing-Ling Wang1, and Alten F. Grandt, Jr.2 FATIGUE ANALYSIS OF MULTIPLE...34 Effect of Prior Corrosion on the S/N Fatigue Performance of Aluminum Sheet Alloys 2024 -T3 and 2524-T3, Effects of the

  16. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks...

  17. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks...

  18. Molecular and eco-physiological characterization of arsenic (As)-transforming Achromobacter sp. KAs 3-5T from As-contaminated groundwater of West Bengal, India.

    PubMed

    Mohapatra, Balaram; Satyanarayana, Tulasi; Sar, Pinaki

    2018-05-02

    Molecular and eco-physiological characterization of arsenic (As)-transforming and hydrocarbon-utilizing Achromobacter type strain KAs 3-5 T has been investigated in order to gain an insight into As-geomicrobiology in the contaminated groundwater. The bacterium is isolated from As-rich groundwater of West Bengal, India. Comparative 16S rRNA gene sequence phylogenetic analysis confirmed that the strain KAs 3-5 T is closely related to Achromobacter mucicolens LMG 26685 T (99.17%) and Achromobacter animicus LMG 26690 T (99.17%), thus affiliated to the genus Achromobacter. Strain KAs 3-5 T is nonflagellated, mesophilic, facultative anaerobe, having a broad metabolic repertoire of using various sugars, sugar-/fatty acids, hydrocarbons as principal carbon substrates, and O 2 , NO 3 - , NO 2 - , and Fe 3+ as terminal electron acceptors. Growth with hydrocarbons led to cellular aggregation and adherence of the cells to the hydrocarbon particles confirmed through electron microscopic observations. The strain KAs 3-5 T showed high As resistance (MIC of 5 mM for As 3+ , 25 mM for As 5+ ) and reductive transformation of As 5+ under aerobic conditions while utilizing both sugars and hydrocarbons. Molecular taxonomy specified a high genomic GC content (65.5 mol %), ubiquinone 8 (UQ-8) as respiratory quinone, spermidine as predominant polyamine in the bacterium. The differential presence of C 12:0 , C 14:0 2-OH, C 18:1 ω7c, and C 14:0 iso 3-OH/ C 16:1 iso fatty acids, phosphatidylglycerol (PG), phosphatidylcholine (PC), two unknown phospholipid (PL1, PL2) as polar lipids, low DNA-DNA relatedness (33.0-41.0%) with the Achromobacter members, and unique metabolic capacities clearly indicated the distinct genomic and physiological properties of strain KAs 3-5 T among known species of the genus Achromobacter. These findings lead to improve our understanding on metabolic flexibility of bacteria residing in As-contaminated groundwater and As-bacteria interactions within oligotrophic

  19. Generation of High-Frequency P and S Wave Radiation from Underground Explosions

    DTIC Science & Technology

    2011-12-30

    3.0 3.5 4.0 2024-T3, 1.63<tɚ.54 mm Homalite-100 Ti - 6Al - 4V , t=1.2 mm Epoxy/Graphite Fiber Composite (a) (b) Figure 3: Normalized Dynamic Stress... porosity . The gas porosity also gives some information about effects associated with the water table since water saturated rock has zero gas porosity ...medium than to the depth. Since velocity and density are strongly correlated with the gas porosity , it was not possible to determine which had the

  20. QRC Evaluation of Materials and Processes.

    DTIC Science & Technology

    1982-10-01

    Fatigue Crack Growth Data for Normal and "Soft" Aluminum 2024 - T351 65 27...Spectrum Fatigue Crack Growth Data for Normal and "Soft" Aluminum 7075-T651 66 28 Constant Amplitude FCGR Data for Normal and "Soft" Aluminum 2024 - T351 67...in Figure 29. The same trends observed in the spectrum fatigue tests are repeated in the S constant amplitude data: for aluminum 2024 - T351 , the

  1. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture..., CERTIFICATION, AND STANDARDS) United States Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are well...

  2. 7 CFR 51.596 - U.S. Grade AA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. Grade AA. 51.596 Section 51.596 Agriculture..., CERTIFICATION, AND STANDARDS) United States Consumer Standards for Celery Stalks Grades § 51.596 U.S. Grade AA. U.S. Grade AA shall consist of stalks of celery of similar varietal characteristics, which are well...

  3. Yeast mitochondrial threonyl-tRNA synthetase recognizes tRNA isoacceptors by distinct mechanisms and promotes CUN codon reassignment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ling, Jiqiang; Peterson, Kaitlyn M.; Simonovic, Ivana

    2014-03-12

    Aminoacyl-tRNA synthetases (aaRSs) ensure faithful translation of mRNA into protein by coupling an amino acid to a set of tRNAs with conserved anticodon sequences. Here, we show that in mitochondria of Saccharomyces cerevisiae, a single aaRS (MST1) recognizes and aminoacylates two natural tRNAs that contain anticodon loops of different size and sequence. Besides a regular ?? with a threonine (Thr) anticodon, MST1 also recognizes an unusual ??, which contains an enlarged anticodon loop and an anticodon triplet that reassigns the CUN codons from leucine to threonine. Our data show that MST1 recognizes the anticodon loop in both tRNAs, but employsmore » distinct recognition mechanisms. The size but not the sequence of the anticodon loop is critical for ?? recognition, whereas the anticodon sequence is essential for aminoacylation of ??. The crystal structure of MST1 reveals that, while lacking the N-terminal editing domain, the enzyme closely resembles the bacterial threonyl-tRNA synthetase (ThrRS). A detailed structural comparison with Escherichia coli ThrRS, which is unable to aminoacylate ??, reveals differences in the anticodon-binding domain that probably allow recognition of the distinct anticodon loops. Finally, our mutational and modeling analyses identify the structural elements in MST1 (e.g., helix {alpha}11) that define tRNA selectivity. Thus, MTS1 exemplifies that a single aaRS can recognize completely divergent anticodon loops of natural isoacceptor tRNAs and that in doing so it facilitates the reassignment of the genetic code in yeast mitochondria.« less

  4. Electrical Characterization of Microprocessor Memories.

    DTIC Science & Technology

    1981-06-01

    INPUT PULSE 0 TO 3.0 20 T--- MEAN VALUE T AA (30) 3,Y VALUE t:_______ -50 -50 0 25 50 70 75 100 125 CASE TEMPERATURE (O)VENDOR SPEC LIMIT 45 NSEC 40 ...PULSE 0 TO 3.0 T AA MEAN VALUE T AA (3a) = 3a VALUEm ’t -.55 - 40 -25 -10 0 20 35 50 65 80 75 110 125 -CASE TEMPERATURE IN 0 aC Figure 2-2. Address Access...times for 2147H-1 and 2147H-2 were increased 5 nanosec- onds each to 40 and 50 nanoseconds, respectively. For the 2148, the access times were increased

  5. Structures of MART-1 26/27-35Peptide/HLA-A2 Complexes Reveal a Remarkable Disconnect between Antigen Structural Homology and T Cell Recognition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Borbulevych, Oleg Y; Insaidoo, Francis K; Baxter, Tiffany K

    2008-09-17

    Small structural changes in peptides presented by major histocompatibility complex (MHC) molecules often result in large changes in immunogenicity, supporting the notion that T cell receptors are exquisitely sensitive to antigen structure. Yet there are striking examples of TCR recognition of structurally dissimilar ligands. The resulting unpredictability of how T cells will respond to different or modified antigens impacts both our understanding of the physical bases for TCR specificity as well as efforts to engineer peptides for immunomodulation. In cancer immunotherapy, epitopes and variants derived from the MART-1/Melan-A protein are widely used as clinical vaccines. Two overlapping epitopes spanning aminomore » acid residues 26 through 35 are of particular interest: numerous clinical studies have been performed using variants of the MART-1 26-35 decamer, although only the 27-35 nonamer has been found on the surface of targeted melanoma cells. Here, we show that the 26-35 and 27-35 peptides adopt strikingly different conformations when bound to HLA-A2. Nevertheless, clonally distinct MART-1{sub 26/27-35}-reactive T cells show broad cross-reactivity towards these ligands. Simultaneously, however, many of the cross-reactive T cells remain unable to recognize anchor-modified variants with very subtle structural differences. These dichotomous observations challenge our thinking about how structural information on unligated peptide/MHC complexes should be best used when addressing questions of TCR specificity. Our findings also indicate that caution is warranted in the design of immunotherapeutics based on the MART-1 26/27-35 epitopes, as neither cross-reactivity nor selectivity is predictable based on the analysis of the structures alone.« less

  6. Structures of MART-126/27–35 Peptide/HLA-A2 Complexes Reveal a Remarkable Disconnect between Antigen Structural Homology and T Cell Recognition

    PubMed Central

    Borbulevych, Oleg Y.; Insaidoo, Francis K.; Baxter, Tiffany K.; Powell, Daniel J.; Johnson, Laura A.; Restifo, Nicholas P.; Baker, Brian M.

    2007-01-01

    Small structural changes in peptides presented by major histocompatibility complex (MHC) molecules often result in large changes in immunogenicity, supporting the notion that T cell receptors are exquisitely sensitive to antigen structure. Yet there are striking examples of TCR recognition of structurally dissimilar ligands. The resulting unpredictability of how T cells will respond to different or modified antigens impacts both our understanding of the physical bases for TCR specificity as well as efforts to engineer peptides for immunomodulation. In cancer immunotherapy, epitopes and variants derived from the MART-1/Melan-A protein are widely used as clinical vaccines. Two overlapping epitopes spanning amino acid residues 26 through 35 are of particular interest: numerous clinical studies have been performed using variants of the MART-1 26–35 decamer, although only the 27–35 nonamer has been found on the surface of targeted melanoma cells. Here, we show that the 26–35 and 27–35 peptides adopt strikingly different conformations when bound to HLA-A2. Nevertheless, clonally distinct MART-126/27–35-reactive T cells show broad cross-reactivity towards these ligands. Simultaneously, however, many of the cross-reactive T cells remain unable to recognize anchor-modified variants with very subtle structural differences. These dichotomous observations challenge our thinking about how structural information on unligated peptide/MHC complexes should be best used when addressing questions of TCR specificity. Our findings also indicate that caution is warranted in the design of immunotherapeutics based on the MART-1 26/27–35 epitopes, as neither cross-reactivity nor selectivity is predictable based on the analysis of the structures alone. PMID:17719062

  7. Differential Regulation of ERK1/2 and mTORC1 Through T1R1/T1R3 in MIN6 Cells.

    PubMed

    Wauson, Eric M; Guerra, Marcy L; Dyachok, Julia; McGlynn, Kathleen; Giles, Jennifer; Ross, Elliott M; Cobb, Melanie H

    2015-08-01

    The MAPKs ERK1/2 respond to nutrients and other insulin secretagogues in pancreatic β-cells and mediate nutrient-dependent insulin gene transcription. Nutrients also stimulate the mechanistic target of rapamycin complex 1 (mTORC1) to regulate protein synthesis. We showed previously that activation of both ERK1/2 and mTORC1 in the MIN6 pancreatic β-cell-derived line by extracellular amino acids (AAs) is at least in part mediated by the heterodimeric T1R1/T1R3, a G protein-coupled receptor. We show here that AAs differentially activate these two signaling pathways in MIN6 cells. Pretreatment with pertussis toxin did not prevent the activation of either ERK1/2 or mTORC1 by AAs, indicating that G(I) is not central to either pathway. Although glucagon-like peptide 1, an agonist for a G(s-)coupled receptor, activated ERK1/2 well and mTORC1 to a small extent, AAs had no effect on cytosolic cAMP accumulation. Ca(2+) entry is required for ERK1/2 activation by AAs but is dispensable for AA activation of mTORC1. Pretreatment with UBO-QIC, a selective G(q) inhibitor, reduced the activation of ERK1/2 but had little effect on the activation of mTORC1 by AAs, suggesting a differential requirement for G(q). Inhibition of G(12/13) by the overexpression of the regulator of G protein signaling domain of p115 ρ-guanine nucleotide exchange factor had no effect on mTORC1 activation by AAs, suggesting that these G proteins are also not involved. We conclude that AAs regulate ERK1/2 and mTORC1 through distinct signaling pathways.

  8. Differential Regulation of ERK1/2 and mTORC1 Through T1R1/T1R3 in MIN6 Cells

    PubMed Central

    Wauson, Eric M.; Guerra, Marcy L.; Dyachok, Julia; McGlynn, Kathleen; Giles, Jennifer; Ross, Elliott M.

    2015-01-01

    The MAPKs ERK1/2 respond to nutrients and other insulin secretagogues in pancreatic β-cells and mediate nutrient-dependent insulin gene transcription. Nutrients also stimulate the mechanistic target of rapamycin complex 1 (mTORC1) to regulate protein synthesis. We showed previously that activation of both ERK1/2 and mTORC1 in the MIN6 pancreatic β-cell-derived line by extracellular amino acids (AAs) is at least in part mediated by the heterodimeric T1R1/T1R3, a G protein-coupled receptor. We show here that AAs differentially activate these two signaling pathways in MIN6 cells. Pretreatment with pertussis toxin did not prevent the activation of either ERK1/2 or mTORC1 by AAs, indicating that Gi is not central to either pathway. Although glucagon-like peptide 1, an agonist for a Gs-coupled receptor, activated ERK1/2 well and mTORC1 to a small extent, AAs had no effect on cytosolic cAMP accumulation. Ca2+ entry is required for ERK1/2 activation by AAs but is dispensable for AA activation of mTORC1. Pretreatment with UBO-QIC, a selective Gq inhibitor, reduced the activation of ERK1/2 but had little effect on the activation of mTORC1 by AAs, suggesting a differential requirement for Gq. Inhibition of G12/13 by the overexpression of the regulator of G protein signaling domain of p115 ρ-guanine nucleotide exchange factor had no effect on mTORC1 activation by AAs, suggesting that these G proteins are also not involved. We conclude that AAs regulate ERK1/2 and mTORC1 through distinct signaling pathways. PMID:26168033

  9. Data-Science Analysis of the Macro-scale Features Governing the Corrosion to Crack Transition in AA7050-T7451

    NASA Astrophysics Data System (ADS)

    Co, Noelle Easter C.; Brown, Donald E.; Burns, James T.

    2018-05-01

    This study applies data science approaches (random forest and logistic regression) to determine the extent to which macro-scale corrosion damage features govern the crack formation behavior in AA7050-T7451. Each corrosion morphology has a set of corresponding predictor variables (pit depth, volume, area, diameter, pit density, total fissure length, surface roughness metrics, etc.) describing the shape of the corrosion damage. The values of the predictor variables are obtained from white light interferometry, x-ray tomography, and scanning electron microscope imaging of the corrosion damage. A permutation test is employed to assess the significance of the logistic and random forest model predictions. Results indicate minimal relationship between the macro-scale corrosion feature predictor variables and fatigue crack initiation. These findings suggest that the macro-scale corrosion features and their interactions do not solely govern the crack formation behavior. While these results do not imply that the macro-features have no impact, they do suggest that additional parameters must be considered to rigorously inform the crack formation location.

  10. High-Speed Friction Stir Welding of AA7075-T6 Sheet: Microstructure, Mechanical Properties, Micro-texture, and Thermal History

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Jingyi; Upadhyay, Piyush; Hovanski, Yuri

    Friction-stir-welding (FSW) is a cost-effective and high quality joining process for aluminum alloys (especially heat-treatable allo ys) that has been applied successfully in the aerospace industry. However, the full potential of FSW on more cost-sensitive applications is still limited by the production rate, namely the welding speed of the process. The majority of literature evaluating FSW of aluminum alloys is based on welds made in the range of welding speeds around hundreds of millimeters per minute, and only a handful are at a moderate speed of 1 m/min. In this study we present a microstructural analysis of friction stir weldedmore » AA7075-T6 blanks with welding speeds up to 3 m/min. Textures, microstructures, mechanical properties, and weld quality are analyzed using TEM, EBSD, metallographic imaging, and Vickers hardness. Results are coupled with welding parameters to aid in the understanding of the complex material flow and texture gradients within the welds in an effort to optimize welding parameters for high speed processing.« less

  11. F-35 Joint Strike Fighter: Development of New Capabilities Requires Continued Oversight

    DTIC Science & Technology

    2016-04-26

    Expected at 10:00 a.m. ET Tuesday, April 26, 2016 GAO-16-634T United States Government Accountability Office Letter Page 1 GAO-16-634T F-35...difficult for Congress to hold it accountable for achieving its cost, schedule, and performance requirements. Given that congressional oversight... Accountability Office, the audit, evaluation, and investigative arm of Congress, exists to support Congress in meeting its constitutional

  12. F-35 Joint Strike Fighter Aircraft (F-35)

    DTIC Science & Technology

    2013-12-01

    Critical Design Review; announcing the decision to terminate development of an alternate Helmet Mounted Display System (HMDS); completing the 2nd F-35B...the 100th aircraft from the production facility at Fort Worth, Texas; and resolving lingering technical design shortfalls to include the F-35C...emphasis on: regular design reviews, systems engineering discipline, software development planning with baseline review boards, and focused metrics

  13. Thermomechanical Fatigue Durability of T650-35/PMR-15 Sheet-Molding Compound Evaluated

    NASA Technical Reports Server (NTRS)

    Castelli, Michael G.

    1999-01-01

    High-performance polymer matrix composites (PMC's) continue to be the focus of a number of research efforts aimed at developing cost-effective, lightweight material alternatives for advanced aerospace and aeropropulsion applications. These materials not only offer significant advantages in specific stiffness and strength over their current metal counterparts, but they can be designed and manufactured to eliminate joints and fasteners by combining individual components into integral subassemblies, thus making them extremely attractive for commercial applications. With much emphasis on the low-cost manufacturing aspects of advanced composite structures, there is heightened interest in high-performance sheet-molding compounds (SMC's). Researchers at the NASA Lewis Research Center, in cooperation with the Allison Advanced Development Company, completed an investigation examining the use of T650-35/PMR-15 SMC for a midstage inner-vane endwall application within a gas turbine engine compressor. This component resides in the engine flow path and is subjected not only to high airflow rates, but also to elevated temperatures and pressures. This application is unique in that it represents a very aggressive use of high-performance SMC's, raising obvious concerns related to durability and property retention in the presence of microstructural damage. Therefore, it was necessary to evaluate the fatigue behavior and damage tolerance of this material subjected to a representative thermomechanical fatigue (TMF) mission-cycle loading spectrum.

  14. Antibacterial and cytotoxic activity of isoprenylated coumarin mammea A/AA isolated from Mammea africana.

    PubMed

    Canning, Corene; Sun, Shi; Ji, Xiangming; Gupta, Smiti; Zhou, Kequan

    2013-05-02

    The stem bark of Mammea africana is widely distributed in tropical Africa and commonly used in traditional medicine. This study aims to identify the active compound in Mammea africana and to evaluate its antimicrobial and antiproliferative activity. Methanol extract from the bark of the Mammea africana was separated by liquid-liquid extraction, followed by open column chromatography. A principal antimicrobial compound was purified by high performance liquid chromatography (HPLC) and its structure was elucidated by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). The antibacterial activity of the purified compound was determined using the broth microdilution method against 7 common pathogenic bacteria. The compound was also evaluated for cytotoxicity by cell proliferation assay (MTS) using the mouse embryonic fibroblast cell line NIH 3T3 and the non-small cell lung cancer cell line A549. The purified active compound was determined to be mammea A/AA and was found to be highly active against Campylobacter jejuni (MIC=0.5 μg/ml), Streptococcus pneumoniae (MIC=0.25 μg/ml), and Clostridium difficile (MIC=0.25 μg/ml). The compound exhibited significant antiproliferative activities against both NIH 3T3 and A549 cell lines. Mammea A/AA isolated from Mammea africana exerts specific inhibitory activity against Campylobacter jejuni, Streptococcus pneumoniae, and Campylobacter difficile. Mammea A/AA was also found to exhibit significant cytotoxicity against both cancer and normal cell lines. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  15. tRNAGlu increases the affinity of glutamyl-tRNA synthetase for its inhibitor glutamyl-sulfamoyl-adenosine, an analogue of the aminoacylation reaction intermediate glutamyl-AMP: mechanistic and evolutionary implications.

    PubMed

    Blais, Sébastien P; Kornblatt, Jack A; Barbeau, Xavier; Bonnaure, Guillaume; Lagüe, Patrick; Chênevert, Robert; Lapointe, Jacques

    2015-01-01

    For tRNA-dependent protein biosynthesis, amino acids are first activated by aminoacyl-tRNA synthetases (aaRSs) yielding the reaction intermediates aminoacyl-AMP (aa-AMP). Stable analogues of aa-AMP, such as aminoacyl-sulfamoyl-adenosines, inhibit their cognate aaRSs. Glutamyl-sulfamoyl-adenosine (Glu-AMS) is the best known inhibitor of Escherichia coli glutamyl-tRNA synthetase (GluRS). Thermodynamic parameters of the interactions between Glu-AMS and E. coli GluRS were measured in the presence and in the absence of tRNA by isothermal titration microcalorimetry. A significant entropic contribution for the interactions between Glu-AMS and GluRS in the absence of tRNA or in the presence of the cognate tRNAGlu or of the non-cognate tRNAPhe is indicated by the negative values of -TΔSb, and by the negative value of ΔCp. On the other hand, the large negative enthalpy is the dominant contribution to ΔGb in the absence of tRNA. The affinity of GluRS for Glu-AMS is not altered in the presence of the non-cognate tRNAPhe, but the dissociation constant Kd is decreased 50-fold in the presence of tRNAGlu; this result is consistent with molecular dynamics results indicating the presence of an H-bond between Glu-AMS and the 3'-OH oxygen of the 3'-terminal ribose of tRNAGlu in the Glu-AMS•GluRS•tRNAGlu complex. Glu-AMS being a very close structural analogue of Glu-AMP, its weak binding to free GluRS suggests that the unstable Glu-AMP reaction intermediate binds weakly to GluRS; these results could explain why all the known GluRSs evolved to activate glutamate only in the presence of tRNAGlu, the coupling of glutamate activation to its transfer to tRNA preventing unproductive cleavage of ATP.

  16. tRNAGlu Increases the Affinity of Glutamyl-tRNA Synthetase for Its Inhibitor Glutamyl-Sulfamoyl-Adenosine, an Analogue of the Aminoacylation Reaction Intermediate Glutamyl-AMP: Mechanistic and Evolutionary Implications

    PubMed Central

    Blais, Sébastien P.; Kornblatt, Jack A.; Barbeau, Xavier; Bonnaure, Guillaume; Lagüe, Patrick; Chênevert, Robert; Lapointe, Jacques

    2015-01-01

    For tRNA-dependent protein biosynthesis, amino acids are first activated by aminoacyl-tRNA synthetases (aaRSs) yielding the reaction intermediates aminoacyl-AMP (aa-AMP). Stable analogues of aa-AMP, such as aminoacyl-sulfamoyl-adenosines, inhibit their cognate aaRSs. Glutamyl-sulfamoyl-adenosine (Glu-AMS) is the best known inhibitor of Escherichia coli glutamyl-tRNA synthetase (GluRS). Thermodynamic parameters of the interactions between Glu-AMS and E. coli GluRS were measured in the presence and in the absence of tRNA by isothermal titration microcalorimetry. A significant entropic contribution for the interactions between Glu-AMS and GluRS in the absence of tRNA or in the presence of the cognate tRNAGlu or of the non-cognate tRNAPhe is indicated by the negative values of –TΔSb, and by the negative value of ΔCp. On the other hand, the large negative enthalpy is the dominant contribution to ΔGb in the absence of tRNA. The affinity of GluRS for Glu-AMS is not altered in the presence of the non-cognate tRNAPhe, but the dissociation constant K d is decreased 50-fold in the presence of tRNAGlu; this result is consistent with molecular dynamics results indicating the presence of an H-bond between Glu-AMS and the 3’-OH oxygen of the 3’-terminal ribose of tRNAGlu in the Glu-AMS•GluRS•tRNAGlu complex. Glu-AMS being a very close structural analogue of Glu-AMP, its weak binding to free GluRS suggests that the unstable Glu-AMP reaction intermediate binds weakly to GluRS; these results could explain why all the known GluRSs evolved to activate glutamate only in the presence of tRNAGlu, the coupling of glutamate activation to its transfer to tRNA preventing unproductive cleavage of ATP. PMID:25860020

  17. Corrosion behaviour of laser-cleaned AA7024 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Zhang, F. D.; Liu, H.; Suebka, C.; Liu, Y. X.; Liu, Z.; Guo, W.; Cheng, Y. M.; Zhang, S. L.; Li, L.

    2018-03-01

    Laser cleaning has been considered as a promising technique for the preparation of aluminium alloy surfaces prior to joining and welding and has been practically used in the automotive industry. The process is based on laser ablation to remove surface contaminations and aluminium oxides. However the change of surface chemistry and oxide status may affect corrosion behaviour of aluminium alloys. Until now, no work has been reported on the corrosion characteristics of laser cleaned metallic surfaces. In this study, we investigated the corrosion behaviour of laser-cleaned AA7024-T4 aluminium alloy using potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). The results showed that the laser-cleaned surface exhibited higher corrosion resistance in 3.5 wt.% NaCl solution than as-received hot-rolled alloy, with significant increase in impedance and decrease in capacitance, while SVET revealed that the active anodic points appeared on the as-received surface were not presented on the laser-cleaned surfaces. Such corrosion behaviours were correlated to the change of surface oxide status measured by glow discharge optical emission spectrometry (GDOES) and X-ray photoelectron spectroscopy (XPS). It was suggested that the removal of the original less protective oxide layer consisting of MgO and MgAl2O4 on the as-received surfaces and the newly formed more protective oxide layer containing mainly Al2O3 and MgO by laser cleaning were responsible for the improvement of the corrosion performance.

  18. NGC 2024: Multi-wavelength Infrared and Radio Observations

    NASA Technical Reports Server (NTRS)

    Smith, H. A.; Fischer, J.; Geballe, T. R.; Thronson, H. A., Jr.; Johnston, K. J.; Schwartz, P. R.; Wilson, T. L.; Crutcher, R. M.; Henkel, C.; Bieging, J.

    1984-01-01

    A series of far-infrared maps obtained on the KAO find the total IR luminosity of NGC 2024 is to the 4th power L, and show a peak in flux density and optical depth about 1' south of IRS 2. High resolution spectra of IRS 2 in Brackett alfa and Pfund gamma indicate the presence of an optically thick wind with M approx. 7 x 10 to the minus 7 power M sub yr to minus 1 power, from which we infer that IRS 2 is unable to supply the luminosity observed. A six centimeter continuum map peaks near the location of the far-infrared peak and confirms it as a likely site for a source to provide this luminosity. Maps in HCN, CS, and H2CO show the gas is dense in the direction of the far IR peak. Velocity analysis shows the H2 region created by the far IR source and IRS 2 forms an expanding bubble in front of which the H2CO is seen in absorption, and which is bounded in the south and behind by dense material.

  19. States' Flexibility Waiver Plans for Alternate Assessments Based on Alternate Achievement Standards (AA-AAS). Synthesis Report 96

    ERIC Educational Resources Information Center

    Lazarus, Sheryl S.; Edwards, Lynn M.; Thurlow, Martha L.; Hodgson, Jennifer R.

    2014-01-01

    All states have alternate assessments based on alternate achievement standards (AA-AAS) for students with the most significant cognitive disabilities. For accountability purposes, the Elementary and Secondary Education Act (ESEA) allows up to 1% of students to be counted as proficient with this assessment option. In 2011 the U.S. Department of…

  20. A GTPase reaction accompanying the rejection of Leu-tRNA2 by UUU-programmed ribosomes. Proofreading of the codon-anticodon interaction by ribosomes.

    PubMed

    Thompson, R C; Dix, D B; Gerson, R B; Karim, A M

    1981-01-10

    The characteristics of a GTPase reaction between poly(U)-programmed ribosomes, EFTu . GTP, and the near-cognate aminoacyl (aa)-tRNA, Leu-tRNA Leu 2, have been studied to assess the role of this reaction in proofreading of the codon-anticodon interaction. The reaction resembles the GTPase reaction with cognate aa-tRNAs and EFTu . GTP in its substrate requirements, in its involving EFTu . GTP . aa-tRNA ternary complexes, and in its requiring a free ribosomal A-site. The noncognate reaction differs from the cognate one in that aa-tRNA becomes stably bound to the ribosomes only 5% of the time; it therefore seems best characterized as an abortive enzymatic binding reaction. The rate of reaction is a significant fraction (4%) of that of the cognate aa-tRNA, indicating that recognition of ternary complexes by ribosomes involves a level of error greater than that of translation as a whole. The rejection of the noncognate aa-tRNA following GTP hydrolysis is therefore a vital step in the translation process and fulfills the criteria set for a proofreading reaction. Leu-tRNA Leu 2 which escapes rejection through proofreading, forms a stable complex with the ribosomal A-site, so it appears that the Leu-tRNA2 which was rejected never reached the A-site and that proofreading precedes full A-site binding.

  1. Quick Reaction Evaluation of Materials for Systems Applications.

    DTIC Science & Technology

    1980-04-01

    The six slack-quenched aluminum alloy plates used in this program were: (1) 2024 -T851; 2.75 inches (60 mm) thick, (2) 2024 - T351 ; 2.00 inches (51 mm...compact (CT) specimen machined from aluminum alloys 7075-T6 and 2024 - T351 , titanium 6A1-4V, and 4340 steel. Deviation between the two curves is small...1.6 Complete Fatigue Crack Growth Rate Curves for Aluminum Alloy 2124-T851 Including Crack Growth Modeling 44 1.7 Crack Length Determination for the

  2. Effects of plastic deformation on microstructure and superplasticity of the in situ Al3Ti/2024Al composites

    NASA Astrophysics Data System (ADS)

    Jiao, Lei; Yang, Yonggang; Li, Hui; Zhao, Yutao; Wang, Xiaolu

    2018-05-01

    In this study, the in situ Al3Ti/2024Al composites were successfully fabricated by direct melt reaction method and subjected to forging and friction stir processing (FSP) to achieve superplasticity. Then, the microstructure and superplastic tensile behavior of the composites were investigated. The results show that the reinforcement particles are broken and grains are fine after plastic processing. Particularly, the size of reinforcement particles ranges from 0.2 μm to 5 μm and the average size of fine equiaxed grains is 5 μm after FSP processing. And the superplasticity of the composites was improved apparently. The maximum elongation of 642% was obtained at 0.15 s‑1 and 510 °C for the FSP specimen, with a strain rate sensitive parameter (m) of 0.58, indicating the FSP specimen has obtained excellent high strain rate superplasticity. The strain rate sensitivity parameter, m, ranges from 0.23 to 0.58, and the activation energy was calculated to be 135.24 kJ mol‑1. All results indicated that the main superplastic deformation mechanism was grain boundary sliding (GBS) for the FSP Al3Ti/2024Al composites.

  3. Effect of Thread and Rotating Speed on Material Flow Behavior and Mechanical Properties of Friction Stir Lap Welding Joints

    NASA Astrophysics Data System (ADS)

    Ji, Shude; Li, Zhengwei; Zhou, Zhenlu; Wu, Baosheng

    2017-10-01

    This study focused on the effects of thread on hook and cold lap formation, lap shear property and impact toughness of alclad 2024-T4 friction stir lap welding (FSLW) joints. Except the traditional threaded pin tool (TR-tool), three new tools with different thread locations and orientations were designed. Results showed that thread significantly affected hook, cold lap morphologies and lap shear properties. The tool with tip-threaded pin (T-tool) fabricated joint with flat hook and cold lap, which resulted in shear fracture mode. The tools with bottom-threaded pin (B-tool) eliminated the hook. The tool with reverse-threaded pin (R-tool) widened the stir zone width. When using configuration A, the joints fabricated by the three new tools showed higher failure loads than the joint fabricated by the TR-tool. The joint using the T-tool owned the optimum impact toughness. This study demonstrated the significance of thread during FSLW and provided a reference to optimize tool geometry.

  4. The Pasadena Recommendations: Five Years After AAS Endorsement

    NASA Astrophysics Data System (ADS)

    Knezek, Patricia; Frattare, L.; Ulvestad, J.

    2010-01-01

    It has been five years since the AAS Council unanimously endorsed the document, known as "Equity Now: The Pasadena Recommendations for Gender Equality in Astronomy," in January 2005. This document was the main product of the conference entitled "Women in Astronomy II: Ten Years After” (WIA II), held in June 2003 in Pasadena, CA. Participants of that 2003 meeting assessed the progress for women in science, offering insights into causes of the slower advancement of women, and discussed strategies to accelerate the achievement of equality. These insights and strategies were then incorporated into the "Pasadena Recommendations" by the CSWA. It was subsequently released to the entire AAS community for review and comments prior to its endorsement by the AAS. We will discuss the Recommendations and their impact since the endorsement by the AAS, including the process that is in place for organizations and departments to formally endorse the Pasadena Recommendations, thus making an organizational commitment to their implementation (see http://www.aas.org/cswa/pasadena_endorse.html).

  5. National Dam Inspection Program. Number 5 Dam (NDI ID Number PA-00375 DER ID Number 35-22), Susquehanna River Basin, Stafford Meadow Brook, Lackawanna County, Pennsylvania. Phase I Inspection Report,

    DTIC Science & Technology

    1979-04-01

    T- 8. A ~~3.1 _CS4 1;93. /7 (.., CIg*. ’~~~ 1 /18.3 4 3~o ~1,61 ),S V. rorr 3-L~’w 5^ Fb6L 0~’cr Qva )m4 - C 4 P7-7~c/ ~4 Sol$ SUSJCT P~~~ILE NO...GANNETT FLEMING CORDDRY AND CARPENTER, INc D 0 C Consulting Engineers C) Hanisburg, Pennsylvania 17105 LUFor - 1 ’ UL -3U lU W. DEPARTMENT OF THE ARMY A...LACKAWANNA COUNTY PENNSYLVANIA t\\)~Avv 2’oe 5 DAM (NDI IDA A-M𔄁 - DR LD Mw35-22)_. $Jac~wvn" cC Rsve-Aj s ; 1 4 C~cIM cAa PHASE I INSPEC TIONBEPORT NATIONAL

  6. Mechanical Properties of T650-35/AFR-PE-4 at Elevated Temperatures for Lightweight Aeroshell Designs

    NASA Technical Reports Server (NTRS)

    Whitley, Karen S.; Collins, TImothy J.

    2006-01-01

    Considerable efforts have been underway to develop multidisciplinary technologies for aeroshell structures that will significantly increase the allowable working temperature for the aeroshell components, and enable the system to operate at higher temperatures while sustaining performance and durability. As part of these efforts, high temperature polymer matrix composites and fabrication technologies are being developed for the primary load bearing structure (heat shield) of the spacecraft. New high-temperature resins and composite material manufacturing techniques are available that have the potential to significantly improve current aeroshell design. In order to qualify a polymer matrix composite (PMC) material as a candidate aeroshell structural material, its performance must be evaluated under realistic environments. Thus, verification testing of lightweight PMC's at aeroshell entry temperatures is needed to ensure that they will perform successfully in high-temperature environments. Towards this end, a test program was developed to characterize the mechanical properties of two candidate material systems, T650-35/AFR-PE-4 and T650-35/RP46. The two candidate high-temperature polyimide resins, AFR-PE-4 and RP46, were developed at the Air Force Research Laboratory and NASA Langley Research Center, respectively. This paper presents experimental methods, strength, and stiffness data of the T650-35/AFR-PE-4 material as a function of elevated temperatures. The properties determined during the research test program herein, included tensile strength, tensile stiffness, Poisson s ratio, compressive strength, compressive stiffness, shear modulus, and shear strength. Unidirectional laminates, a cross-ply laminate and two eight-harness satin (8HS)-weave laminates (4-ply and 10-ply) were tested according to ASTM standard methods at room and elevated temperatures (23, 316, and 343 C). All of the relevant test methods and data reduction schemes are outlined along with

  7. Effect of pin tool design on the material flow of dissimilar AA7075-AA6061 friction stir welds

    NASA Astrophysics Data System (ADS)

    Hasan, Mohammed M.; Ishak, M.; Rejab, M. R. M.

    2017-10-01

    Tool design is the most influential aspect in the friction stir welding (FSW) technology. Influence of pin tool geometry on material flow pattern are studied in this work during the FSW of dissimilar AA7075 and AA6061 aluminium alloys. Three truncated pin tool profiles (threaded, threaded with single flat, and unthreaded with single flat) were used to prepare the weldments. The workpieces were joined using a custom-made clamping system under 1100 rpm of spindle speed, 300 mm/min of traverse rate and 3° of tilt angle. The metallographic analysis showed that defect-free welds can be produced using the three pin tools with significant changes in the mixing stir zone structure. The results declared that the introducing of the flat on the cone of the probe deviates the pattern of the onion rings without changing the chemical composition of the created layers. This in turn improves the hardness distribution and tensile strength of the welded joint. It was also noted that both heat affected zone (HAZ) and thermal-mechanical affected zone (TMAZ) are similar in composition to their corresponding base materials (BM).

  8. Mechanical characterization of Al-2024 reinforced with fly ash and E-glass by stir casting method

    NASA Astrophysics Data System (ADS)

    Ramesh, B. T.; Swamy, R. P.; Vinayak, Koppad

    2018-04-01

    The properties of MMCs enhance their handling in automotive and various applications for the reason that of encouraging properties of high stiffness and high strength, low density, high electrical and thermal conductivity, corrosion resistance, improved wear resistance etc. Metal Matrix Composites are a vital family of materials designed at achieving an improved combination of properties. Our paper deals through to fabricate Hybrid Composite by heating Al 2024 in furnace at a temperature of around 4000 C. E-Glass fiber & Fly ash will be added to the molten metal with changing weight fractions and stirred strongly. Then the ensuing composition will poured into the mould to obtain hybrid composite casting. Aluminium alloy (2024) is the matrix metal used in the present investigation. Fly ash and e-glass are used as the reinforced materials to produce the composite by stir casting. Fly ash is selected because of it is less expensive and low density reinforcement available in great quantities as solid disposal from thermal power plants. The Test specimen is prepared as per ASTM standards size by machining operations to conduct Tensile, Compression, Hardness, and wear test. The test specimens are furnished for tensile, compression strength and wear as per ASTM standard E8, E9 and G99 respectively using Universal Testing Machine and pin on disk machine. It is seen that the fabricated MMC obtained has got enhanced mechanical strength.

  9. Corrosion-Prevention Capabilities of a Water-Borne, Silicone-Based, Primerless Coating

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; MacDowell, Louis G.; Vinje, Rubie D.

    2005-01-01

    Comparative tests have been performed to evaluate the corrosion-prevention capabilities of an experimental paint of the type described in Water-Borne, Silicone-Based, Primerless Paints, NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 30. To recapitulate: these paints contain relatively small amounts of volatile organic solvents and were developed as substitutes for traditional anticorrosion paints that contain large amounts of such solvents. An additional desirable feature of these paints is that they can be applied without need for prior application of primers to ensure adhesion. The test specimens included panels of cold-rolled steel, stainless steel 316, and aluminum 2024-T3. Some panels of each of these alloys were left bare and some were coated with the experimental water-borne, silicone-based, primerless paint. In addition, some panels of aluminum 2024-T3 and some panels of a fourth alloy (stainless steel 304) were coated with a commercial solvent-borne paint containing aluminum and zinc flakes in a nitrile rubber matrix. In the tests, the specimens were immersed in an aerated 3.5-weight-percent aqueous solution of NaCl for 168 hours. At intervals of 24 hours, the specimens were characterized by electrochemical impedance spectroscopy (EIS) and measurements of corrosion potentials. The specimens were also observed visually. As indicated by photographs of specimens taken after the 168-hour immersion (see figure), the experimental primerless silicone paint was effective in preventing corrosion of stainless steel 316, but failed to protect aluminum 2024-T3 and cold-rolled steel. The degree of failure was greater in the case of the cold-rolled steel. On the basis of visual observations, EIS, and corrosion- potential measurements, it was concluded that the commercial aluminum and zinc-filled nitrile rubber coating affords superior corrosion protection to aluminum 2024-T3 and is somewhat less effective in protecting stainless steel 304.

  10. Genetic Validation of Aminoacyl-tRNA Synthetases as Drug Targets in Trypanosoma brucei

    PubMed Central

    Kalidas, Savitha; Cestari, Igor; Monnerat, Severine; Li, Qiong; Regmi, Sandesh; Hasle, Nicholas; Labaied, Mehdi; Parsons, Marilyn; Stuart, Kenneth

    2014-01-01

    Human African trypanosomiasis (HAT) is an important public health threat in sub-Saharan Africa. Current drugs are unsatisfactory, and new drugs are being sought. Few validated enzyme targets are available to support drug discovery efforts, so our goal was to obtain essentiality data on genes with proven utility as drug targets. Aminoacyl-tRNA synthetases (aaRSs) are known drug targets for bacterial and fungal pathogens and are required for protein synthesis. Here we survey the essentiality of eight Trypanosoma brucei aaRSs by RNA interference (RNAi) gene expression knockdown, covering an enzyme from each major aaRS class: valyl-tRNA synthetase (ValRS) (class Ia), tryptophanyl-tRNA synthetase (TrpRS-1) (class Ib), arginyl-tRNA synthetase (ArgRS) (class Ic), glutamyl-tRNA synthetase (GluRS) (class 1c), threonyl-tRNA synthetase (ThrRS) (class IIa), asparaginyl-tRNA synthetase (AsnRS) (class IIb), and phenylalanyl-tRNA synthetase (α and β) (PheRS) (class IIc). Knockdown of mRNA encoding these enzymes in T. brucei mammalian stage parasites showed that all were essential for parasite growth and survival in vitro. The reduced expression resulted in growth, morphological, cell cycle, and DNA content abnormalities. ThrRS was characterized in greater detail, showing that the purified recombinant enzyme displayed ThrRS activity and that the protein localized to both the cytosol and mitochondrion. Borrelidin, a known inhibitor of ThrRS, was an inhibitor of T. brucei ThrRS and showed antitrypanosomal activity. The data show that aaRSs are essential for T. brucei survival and are likely to be excellent targets for drug discovery efforts. PMID:24562907

  11. Genotoxicity of 2,6- and 3,5-Dimethylaniline in Cultured Mammalian Cells: The Role of Reactive Oxygen Species

    PubMed Central

    Chao, Ming-Wei; Kim, Min Young; Wogan, Gerald N.

    2012-01-01

    Several alkylanilines with structures more complex than toluidines have been associated epidemiologically with human cancer. Their mechanism of action remains largely undetermined, and there is no reported evidence that it replicates that of multicyclic aromatic amines even though the principal metabolic pathways of P450-mediated hydroxylation and phase II conjugation are very similar. As a means to elucidate their mechanisms of action, lethality and mutagenicity in the adenine phosphoribosyltransferase (aprt +/−) gene induced in several Chinese hamster ovary cell types by 2,6- and 3,5-dimethylaniline (2,6-DMA, 3,5-DMA) and their N- and ring-hydroxyl derivatives (N-OH-2,6-DMA, N-OH-3,5-DMA, 2,6-DMAP, 3,5-DMAP) were assessed. Dose-response relationships were determined in the parental AA8 cell line, its repair-deficient UV5 subclone and other repair-deficient 5P3NAT2 or -proficient 5P3NAT2R9 subclones engineered to express mouse cytochrome P4501A2 (CYP1A2) and human N-acetyltransferase (NAT2), and also in AS52 cells harboring the bacterial guanine-hypoxanthine phosphoribosyltransferase (gpt) gene. Mutations in the gpt gene of AS52 cells were characterized and found to be dominated by G:C to A:T and A:T to G:C transitions. Separately, treatment of AS52 cells with N-OH-2,6-DMA, N-OH-3,5-DMA, 2,6-DMAP, 3,5-DMAP, and 3,5-DMAP led to intracellular production of reactive oxygen species (ROS) for at least 24h after removal of the mutagens in every case. Using the comet assay, DNA strand breaks were observed in a dose-dependent manner in AS52 cells when treated with each of the four N-OH-2,6-DMA, N-OH-3,5-DMA, 2,6-DMAP, and 3,5-DMAP derivatives. Comparative evaluation of the results indicates that the principal mechanism of mutagenic action is likely to be through redox cycling of intracellularly bound aminophenol/quinone imine structures to generate ROS rather than through formation of covalent DNA adducts. PMID:22831970

  12. 46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2012-10-01 2012-10-01 false Flashing the rays of a searchlight or other blinding...

  13. 46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2010-10-01 2010-10-01 false Flashing the rays of a searchlight or other blinding...

  14. 46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2014-10-01 2014-10-01 false Flashing the rays of a searchlight or other blinding...

  15. 46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2013-10-01 2013-10-01 false Flashing the rays of a searchlight or other blinding...

  16. 46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2011-10-01 2011-10-01 false Flashing the rays of a searchlight or other blinding...

  17. A genomically modified Escherichia coli strain carrying an orthogonal E. coli histidyl-tRNA synthetase•tRNAHis pair.

    PubMed

    Englert, Markus; Vargas-Rodriguez, Oscar; Reynolds, Noah M; Wang, Yane-Shih; Söll, Dieter; Umehara, Takuya

    2017-11-01

    Development of new aminoacyl-tRNA synthetase (aaRS)•tRNA pairs is central for incorporation of novel non-canonical amino acids (ncAAs) into proteins via genetic code expansion (GCE). The Escherichia coli and Caulobacter crescentus histidyl-tRNA synthetases (HisRS) evolved divergent mechanisms of tRNA His recognition that prevent their cross-reactivity. Although the E. coli HisRS•tRNA His pair is a good candidate for GCE, its use in C. crescentus is limited by the lack of established genetic selection methods and by the low transformation efficiency of C. crescentus. E. coli was genetically engineered to use a C. crescentus HisRS•tRNA His pair. Super-folder green fluorescent protein (sfGFP) and chloramphenicol acetyltransferase (CAT) were used as reporters for read-through assays. A library of 313 ncAAs coupled with the sfGFP reporter system was employed to investigate the specificity of E. coli HisRS in vivo. A genomically modified E. coli strain (named MEOV1) was created. MEVO1 requires an active C. crescentus HisRS•tRNA His pair for growth, and displays a similar doubling time as the parental E. coli strain. sfGFP- and CAT-based assays showed that the E. coli HisRS•tRNA His pair is orthogonal in MEOV1 cells. A mutation in the anticodon loop of E. coli tRNA His CUA elevated its suppression efficiency by 2-fold. The C. crescentus HisRS•tRNA His pair functionally complements an E. coli ΔhisS strain. The E. coli HisRS•tRNA His is orthogonal in MEOV1 cells. E. coli tRNA His CUA is an efficient amber suppressor in MEOV1. We developed a platform that allows protein engineering of E. coli HisRS that should facilitate GCE in E. coli. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Elevated expression of CX3C chemokine receptor 1 mediates recruitment of T cells into bone marrow of patients with acquired aplastic anaemia.

    PubMed

    Ren, J; Hou, X Y; Ma, S H; Zhang, F K; Zhen, J H; Sun, L; Sun, Y X; Hao, Y L; Cheng, Y F; Hou, M; Xu, C G; Zhang, M H; Peng, J

    2014-11-01

    Acquired aplastic anaemia (AA) is a T-cell-mediated, organ-specific autoimmune disease characterized by haematopoietic stem cell destruction in the bone marrow. The exact molecular mechanism of T-cell trafficking into the bone marrow is unclear in AA. Very late activation antigen-4 (VLA-4) and CX3C chemokine receptor 1 (CX3CR1) play active roles in many autoimmune diseases. Therefore, we investigated whether VLA-4 and CX3CR1 also contribute to T-cell migration into the bone marrow in acquired AA. Expression levels of CX3CR1 and VLA-4 and their ligands [fractalkine (CX3CL1) and vascular cell adhesion molecule-1 (VCAM-1)] were examined in 63 patients with AA and 21 healthy control subjects. T-cell chemotaxis and adhesion were analysed in 17 patients with severe AA. We also prospectively evaluated the expression pattern of CX3CR1 during treatment with antithymocyte globulin plus cyclosporine in 11 patients with severe AA. The proportion of peripheral and bone marrow CD4(+) and CD8(+) T cells expressing CX3CR1 and the level of CX3CL1 was increased in patients with AA. However, there was no significant difference in VLA-4 expression or VCAM-1 levels. Functional studies demonstrated that chemotaxis towards autologous bone marrow plasma or soluble CX3CL1 was significantly higher in T cells from AA patients and could be blocked by CX3CR1 inhibitors. CX3CR1-mediated T-cell adhesion was also upregulated in these patients. The expression of CX3CR1 was associated with the efficacy of immunosuppressive therapy. The present findings demonstrate that CX3CR1 plays a pivotal role in recruitment of T cells into the bone marrow in acquired AA and is a potential therapeutic target for treatment of this disorder. © 2014 The Association for the Publication of the Journal of Internal Medicine.

  19. Arachidonic acid-and docosahexaenoic acid-enriched formulas modulate antigen-specific T cell responses to influenza virus in neonatal piglets.

    PubMed

    Bassaganya-Riera, Josep; Guri, Amir J; Noble, Alexis M; Reynolds, Kathryn A; King, Jennifer; Wood, Cynthia M; Ashby, Michael; Rai, Deshanie; Hontecillas, Raquel

    2007-03-01

    Whereas the immunomodulatory effects of feeding either arachidonic acid (AA) or docosahexaenoic acid (DHA) separately have been previously investigated, little is known about the immunomodulatory efficacy of AA or DHA when they are fed in combination as infant formula ingredients. The objective of this study was to investigate the ability of AA- and DHA(AA/DHA)-enriched infant formula to modulate immune responses in the neonate in response to an inactivated influenza virus vaccine. Neonatal piglets (n = 48) were weaned on day 2 of age and distributed into 16 blocks of 3 littermate piglets each. Within each block, piglets were randomly assigned to a control formula, AA/DHA-enriched formula (0.63% AA and 0.34% DHA), or sow milk for 30 d. On day 9, 8 blocks of piglets were immunized with an inactivated influenza virus vaccine. On days 0, 9, 16, 23, and 30 after weaning, we measured influenza virus-specific T cell proliferation and phenotype of T subsets in peripheral blood. A delayed-type hypersensitivity reaction test was administered on day 28. Cytokine messenger RNA expression was determined by quantitative real time reverse transcriptase-polymerase chain reaction on day 30. The influenza virus-specific CD4(+) and CD8(+) T cell ex vivo lymphoproliferative responses were significantly lower on day 23 after immunization in piglets receiving dietary AA/DHA supplementation and sow milk than in those receiving the unsupplemented control formula. The immunomodulatory effects of AA/DHA-enriched formulas were consistent with up-regulation of interleukin 10 in peripheral blood mononuclear cells. Overall, it appears that the AA/DHA-enriched formula modulated antigen-specific T cell responses in part through an interleukin 10-dependent mechanism.

  20. Exploring the evolutionary diversity and assembly modes of multi-aminoacyl-tRNA synthetase complexes: lessons from unicellular organisms.

    PubMed

    Laporte, Daphné; Huot, Jonathan L; Bader, Gaétan; Enkler, Ludovic; Senger, Bruno; Becker, Hubert Dominique

    2014-11-28

    Aminoacyl-tRNA synthetases (aaRSs) are ubiquitous and ancient enzymes, mostly known for their essential role in generating aminoacylated tRNAs. During the last two decades, many aaRSs have been found to perform additional and equally crucial tasks outside translation. In metazoans, aaRSs have been shown to assemble, together with non-enzymatic assembly proteins called aaRSs-interacting multifunctional proteins (AIMPs), into so-called multi-synthetase complexes (MSCs). Metazoan MSCs are dynamic particles able to specifically release some of their constituents in response to a given stimulus. Upon their release from MSCs, aaRSs can reach other subcellular compartments, where they often participate to cellular processes that do not exploit their primary function of synthesizing aminoacyl-tRNAs. The dynamics of MSCs and the expansion of the aaRSs functional repertoire are features that are so far thought to be restricted to higher and multicellular eukaryotes. However, much can be learnt about how MSCs are assembled and function from apparently 'simple' organisms. Here we provide an overview on the diversity of these MSCs, their composition, mode of assembly and the functions that their constituents, namely aaRSs and AIMPs, exert in unicellular organisms. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  1. The Association Between MCT1 T1470A Polymorphism and Power-Oriented Athletic Performance.

    PubMed

    Kikuchi, N; Fuku, N; Matsumoto, R; Matsumoto, S; Murakami, H; Miyachi, M; Nakazato, K

    2017-01-01

    The purpose of this study was to investigate the effects of the MCT1 T1470A polymorphism (rs1049434) on power-oriented performance and lactate concentration during or after cycling sprints in Japanese wrestlers. Participants (199 wrestlers and 649 controls) were genotyped for the MCT1 T1470A genotype (rs1049434) using the TaqMan ® Assay. All wrestlers were international (n=77) or national (n=122) level athletes. Among them, 46 wrestlers performed 2 anaerobic performance tests, a 30-s Wingate Anaerobic test (WAnT) and a series of 10 maximal effort 10-s sprints on a cycle ergometer. Blood lactate levels were measured before, during, and after the tests. In the A-allele recessive model (AA vs. TA+TT), the frequency of the AA genotype was significantly higher in all wrestlers than in controls (p=0.037). Wrestlers with AA genotype had lower blood lactate concentrations than those with TA+TT genotype at 10 min after the WAnT and following the 5 th and the final set of repeated cycling sprints (p<0.05). The AA genotype of the MCT1 T1470A polymorphism is over-represented in wrestlers compared with controls and is associated with lower blood lactate concentrations after 30-s WAnT and during intermittent sprint tests in Japanese wrestlers. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Damage Tolerant Design Handbook. A Compilation of Fracture and Crack- Growth Data for High-Strength Alloys. Volume 3

    DTIC Science & Technology

    1983-12-01

    Effects on the Fatigue Crack Growth Rate of Aluminum Alloy 2024 - T351 ", University of Dayton Research Institute, Dayton, OH, Contract No. F33615-80-C-5011...ASSOCIATED WITH FIGURE 7.5.3.9 INDICATING EFFECT OF STRESS RATIO MATERIAL: ALUMINUM 2024 CONDITION: T351 ENVIRONMENT: R.T. LAB AIR DELTA K .DA/DN (10...OF STRESS INTENSITY FACTOR DATA ASSOCIATED WITH FIGURE 7.5.3.10 INDICATING EFFECT OF STRESS RATIO MATERIAL: ALUMINUM 2024

  3. Characteristics of AA amyloidosis patients in San Francisco.

    PubMed

    Lejmi, Hiba; Jen, Kuang-Yu; Olson, Jean L; James, Sam H; Sam, Ramin

    2016-04-01

    AA amyloidosis due to subcutaneous injection of drugs of abuse has been described in the USA, but all the existing literature is from more than 20 years ago. There is more recent literature from Europe. We have observed a high incidence of AA amyloidosis in the county hospital in San Francisco. Here, we describe 24 patients who had kidney biopsy-proven AA amyloidosis from our hospital from 1998 to 2013. All the patients were thought to have AA amyloidosis from skin popping of illicit drugs after having exhausted the intravenous route. These patients with biopsy-proven AA amyloidosis were analysed further. All patients were found to have hepatitis C infection, hypertension was not common, most had advanced kidney failure, and acidosis was common as was tubulointerstitial involvement on the kidney biopsy. Other organ involvement included hepatomegaly and splenomegaly in a number of patients; direct myocardial involvement was not seen, but pulmonary hypertension, history of deep vein thrombosis and pulmonary embolism were common. The prognosis of these patients was poor. The mortality rate approached 50% 1 year after biopsy, and most of the patient needed dialysis shortly after diagnosis. Cessation of drug use seemed beneficial but rarely achievable. AA amyloidosis from skin popping is common in San Francisco. Most patients with renal involvement end up on dialysis, and mortality rates are exceedingly high. © 2015 Asian Pacific Society of Nephrology.

  4. MDCT evaluation of acute aortic syndrome (AAS)

    PubMed Central

    Rossi, Giovanni; Lassandro, Francesco; Rea, Gaetano; Marino, Maurizio; Muto, Maurizio; Molino, Antonio; Scaglione, Mariano

    2016-01-01

    Non-traumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. There is a common pathway for the various manifestations of AAS that eventually leads to a breakdown of the aortic intima and media. Improvements in biology and health policy and diffusion of technology into the community resulted in an associated decrease in mortality and morbidity related to aortic therapeutic interventions. Hybrid procedures, branched and fenestrated endografts, and percutaneous aortic valves have emerged as potent and viable alternatives to traditional surgeries. In this context, current state-of-the art multidetector CT (MDCT) is actually the gold standard in the emergency setting because of its intrinsic diagnostic value. Management of acute aortic disease has changed with the increasing realization that endovascular therapies may offer distinct advantages in these situations. This article provides a summary of AAS, focusing especially on the MDCT technique, typical and atypical findings and common pitfalls of AAS, as well as recent concepts regarding the subtypes of AAS, consisting of aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer and unstable aortic aneurysm or contained aortic rupture. MDCT findings will be related to pathophysiology, timing and management options to achieve a definite and timely diagnostic and therapeutic definition. In the present article, we review the aetiology, pathophysiology, clinical presentation, outcomes and therapeutic approaches to acute aortic syndromes. PMID:27033344

  5. AAS 227: Day 2

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    tests of GR, and performing predictive GRMHD simulations hydrodynamics simulations that include magnetic fields and full GR treatment. Ozel pointed out that one of the recent theoretical advancements in GRMHD simulations is harnessing the power of GPUs to render images in simulations; check out the tweet below for the awesome video she showed us!Watch C. Chan manipulate black hole simulation with hand motions https://t.co/O5BgaltYAu (more on the code: https://t.co/9GC46ReMGs) #aas227 Sarah Scoles (@ScolesSarah) January 6, 2016Deployment of the full EHT array is planned for early 2017, and theyve already got 10 targets selected black holes that are near enough and large enough that the EHT should be able to image their shadows. I, for one, cant wait to see the first results!Grad School and Postdocs as a Means to a Job (by Meredith Rawls)This morning session was presented by Karen Kelsky of The Professor Is In. She presented a very practical overview of the advice in her book (which this job-searching Astrobiter highly recommends). Her target audience is postdocs and graduate students who are finishing their PhDs and applying for tenure-track jobs. Karens background is in the social sciences, but she has worked with many scientists and her expertise easily transferred. Much of her writing advice also applies for undergraduates who are writing research statements and proposals to apply to graduate school. For example:What not to do, with @ProfessorIsIn #aas227 pic.twitter.com/afGAsSuPwN Meredith Rawls (@merrdiff) January 6, 2016One of Karens main takeaways is that academia is not automatically good preparation for a job search. Writing documents like cover letters, resumes, and research statements will be harder and take more time than you think, and it is important to make them top-notch. Karen was also surprised that the majority of professional astronomers at the AAS meeting carry backpacks, because she typically advises against bringing a backpack to a job interview or

  6. Comparison of calculated and experimentally determined SID of CP and AA in complex diets differing in AA contents for grower finisher pigs.

    PubMed

    Büsing, K; Berk, A; Müller, S; Kieckhäven, S; Krüger, K; Zeyner, A

    2017-10-01

    In practice, the content of standardized ileal digestible AA in complex feeds for pigs is calculated on the basis of tabulated values for individual feedstuffs. It comes into question, however, whether this truly reflects an accurate content based upon the estimate made for the individual feedstuffs. The objective of this study was to compare standardized ileal digestibility (SID) of crude protein (CP) and selected AA in complex feeds for grower and finisher pigs either calculated or experimentally determined. Six diets with increasing AA levels were prepared for grower (BW from 30 to 70 kg) and finisher (BW from 70 to 120 kg) feed. Crystalline L-lys, DL-met and L-thr were added to both diets, L-trp and L-val only to the grower feed. SID of both CP and AA was calculated from feed tables and experimentally determined in six adult minipigs (MINILEWE) with ileorectal anastomosis. With increasing AA levels, experimentally determined SID of supplemented AA increased (p < 0.05), but SID of CP (p ≥ 0.05) was not affected. In both grower and finisher feed, calculated and experimentally determined SID of CP, Met, Cys, Trp, Ile and Tyr differed by more than 2% units, but those of Lys and His only in the finisher feed. Yet this effect was not directly consistent. The margin of error following estimation of SID of AA via tabulated values for individual feedstuffs, however, seems to be acceptable for practical use. Journal of Animal Physiology and Animal Nutrition © 2017 Blackwell Verlag GmbH.

  7. Analysing the strength of friction stir welded dissimilar aluminium alloys using Sugeno Fuzzy model

    NASA Astrophysics Data System (ADS)

    Barath, V. R.; Vaira Vignesh, R.; Padmanaban, R.

    2018-02-01

    Friction stir welding (FSW) is a promising solid state joining technique for aluminium alloys. In this study, FSW trials were conducted on two dissimilar plates of aluminium alloy AA2024 and AA7075 by varying the tool rotation speed (TRS) and welding speed (WS). Tensile strength (TS) of the joints were measured and a Sugeno - Fuzzy model was developed to interconnect the FSW process parameters with the tensile strength. From the developed model, it was observed that the optimum heat generation at WS of 15 mm.min-1 and TRS of 1050 rpm resulted in dynamic recovery and dynamic recrystallization of the material. This refined the grains in the FSW zone and resulted in peak tensile strength among the tested specimens. Crest parabolic trend was observed in tensile strength with variation of TRS from 900 rpm to 1200 rpm and TTS from 10 mm.min-1 to 20 mm.min-1.

  8. Joint Force Quarterly. Issue 35

    DTIC Science & Technology

    2004-10-01

    From the Field and Fleet: Letters to the Editor J F Q F O R U M 9 Clausewitz and War 10 Center of Gravity: Recommendations for Joint Doctrine by...D I T S JFQ 129 Trends in Future Warfare by Christopher J. Bowie, Robert P. Haffa, Jr., and Robert E. Mullins 134 The Other Gulf War : British...Book Review by Larry M. Wortzel 146 Wars and Rumors of Wars : A Book Review by James Jay Carafano 108 Revisiting the Korean Tree-Trimming Incident

  9. Effect of Thermomechanical Treatment on the Environmentally Induced Cracking Behavior of AA7075 Alloy

    NASA Astrophysics Data System (ADS)

    Ghosh, Rahul; Venugopal, A.; Sankaravelayudham, P.; Panda, Rajiv; Sharma, S. C.; George, Koshy M.; Raja, V. S.

    2015-02-01

    The influence of thermomechanical treatment on the stress corrosion cracking behavior of AA7075 aluminum alloy forgings was examined in 3.5% NaCl solution by varying the extent of thermomechanical working imparted to each of the conditions. The results show that inadequate working during billet processing resulted in inferior corrosion and mechanical properties. However, more working with intermediate pre-heating stages also led to precipitation of coarse particles resulting in lowering of mechanical properties marginally and a significant reduction in the general/pitting corrosion resistance. The results obtained in the present study indicate that optimum working with controlled pre-heating levels is needed during forging to achieve the desired properties. It is also demonstrated that AA7075 in the over aged condition does not show any environmental cracking susceptibility in spite of the microstructural variations in terms of size and volume fraction of the precipitates. However, the above microstructural variations definitely affected the pitting corrosion and mechanical properties significantly and hence a strict control over the working and pre-heating stages during billet processing is suggested.

  10. 12-Step Therapy and Women with and without Social Phobia: A Study of the Effectiveness of 12-Step Therapy to Facilitate AA Engagement

    PubMed Central

    Tonigan, J. Scott; Book, Sarah W.; Pagano, Maria E.; Randall, Patrick K.; Smith, Joshua P.; Randall, Carrie L.

    2011-01-01

    Alcoholism treatment often encourages involvement in Alcoholics Anonymous (AA). Little provision is made for women with social phobia (SP), who have been reported to have worse outcomes in twelve-step-facilitation (TSF) relative to cognitive behavioral therapy. This study examined whether SP moderated the effects of gender for these women in TSF. 133 SP alcoholics assigned to TSF (35 females and 98 males) in Project MATCH were compared to a non-SP control group. SP women drank earlier and more intensely than non-SP women and all males, had equivalent AA attendance and completion of Step 5, and were less likely to acquire a sponsor during TSF. PMID:21423569

  11. Displaying Now-Understanding: The Finnish Change-of-State Token "aa"

    ERIC Educational Resources Information Center

    Koivisto, Aino

    2015-01-01

    This article discusses the use of the Finnish change-of-state token "aa" that has previously not been identified. The central claim is that even though "aa" indicates a cognitive shift experienced by the speaker, it does not function as a receipt of new information. Instead, the token "aa" indicates that the speaker…

  12. The 9aaTAD Transactivation Domains: From Gal4 to p53.

    PubMed

    Piskacek, Martin; Havelka, Marek; Rezacova, Martina; Knight, Andrea

    2016-01-01

    The family of the Nine amino acid Transactivation Domain, 9aaTAD family, comprises currently over 40 members. The 9aaTAD domains are universally recognized by the transcriptional machinery from yeast to man. We had identified the 9aaTAD domains in the p53, Msn2, Pdr1 and B42 activators by our prediction algorithm. In this study, their competence to activate transcription as small peptides was proven. Not surprisingly, we elicited immense 9aaTAD divergence in hundreds of identified orthologs and numerous examples of the 9aaTAD species' convergence. We found unforeseen similarity of the mammalian p53 with yeast Gal4 9aaTAD domains. Furthermore, we identified artificial 9aaTAD domains generated accidentally by others. From an evolutionary perspective, the observed easiness to generate 9aaTAD transactivation domains indicates the natural advantage for spontaneous generation of transcription factors from DNA binding precursors.

  13. Degradation kinetics of the antioxidant additive ascorbic acid in packed table olives during storage at different temperatures.

    PubMed

    Montaño, A; Casado, F J; Rejano, L; Sanchez, A H; de Castro, A

    2006-03-22

    The kinetics of ascorbic acid (AA) loss during storage of packed table olives with two different levels of added AA was investigated. Three selected storage temperatures were assayed: 10 degrees C, ambient (20-24 degrees C), and 40 degrees C. The study was carried out in both pasteurized and unpasteurized product. The effect of pasteurization treatment alone on added AA was not significant. In the pasteurized product, in general AA degraded following a first-order kinetics. The activation energy calculated by using the Arrhenius model averaged 9 kcal/mol. For each storage temperature, the increase in initial AA concentration significantly decreased the AA degradation rate. In the unpasteurized product, AA was not detected after 20 days in samples stored at room temperature and AA degradation followed zero-order kinetics at 10 degrees C, whereas at 40 degrees C a second-order reaction showed the best fit. In both pasteurized and unpasteurized product, the low level of initial dehydroascorbic acid disappeared during storage. Furfural appeared to be formed during storage, mainly at 40 degrees C, following zero-order kinetics.

  14. Dislocation density evolution of AA 7020-T6 investigated by in-situ synchrotron diffraction under tensile load

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhong, Z.Y., E-mail: zhengye.zhong@hzg.de; Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, D-21502 Geesthacht; Brokmeier, H.-G.

    2015-10-15

    The dislocation density evolution along the loading axis of a textured AA 7020-T6 aluminum alloy during uniaxial tension was investigated by in-situ synchrotron diffraction. The highly parallel synchrotron beam at the High Energy Materials Science beamline P07 in PETRA III, DESY, offers excellent conditions to separate different influences for line broadening from which micro-strains are obtained using the modified Williamson–Hall method which is also for defect density investigations. During tensile loading the dislocation density evolution was documented from the as-received material (initial micro-strain state) to the relaxation of the strains during elastic deformation. After yield, the increasing rate of dislocationmore » density growth was relatively fast till half-way between yield and UTS. After that, the rate started to decrease and the dislocation density fluctuated as the elongation increased due to the generation and annihilation of dislocations. When dislocation generation is dominant, the correlation between the flow stress and dislocation density satisfies the Taylor equation. Besides, a method to correct the thickness effect on peak broadening is developed in the present study. - Highlights: • In-situ synchrotron diffraction was applied to characterize peak broadening. • Dislocation evolution along the loading axis during uniaxial tension was investigated. • A method to correct the sample thickness effect on peak broadening was developed. • Dislocation density and flow stress satisfy the Taylor equation at a certain range. • The texture before load and after sample fracture was analyzed.« less

  15. Spontaneous, Experimentally Induced, and Transmissible AA Amyloidosis in Japanese Quail ( Coturnix japonica).

    PubMed

    Nakayama, Yumi; Kamiie, Junichi; Watanabe, Gen; Suzuki, Kazuhiko; Murakami, Tomoaki

    2017-11-01

    The authors describe a spontaneous case of amyloid A (AA) amyloidosis in an adult female Japanese quail ( Coturnix japonica). The bird developed AA amyloidosis secondary to chronic peritonitis caused by a Gram-negative bacillus infection. Mild amyloid deposition was also identified in the intestinal tract of apparently healthy adult individuals, suggesting that quail may develop intestinal amyloidosis with age. Based on these observations, it was hypothesized that quail can develop AA amyloidosis following inflammatory stimulation with lipopolysaccharide (LPS). Therefore, adult quail were repeatedly injected with LPS and the development of AA amyloidosis was confirmed. The amyloid deposition in this model increased when quail amyloid was intravenously injected as an amyloid-enhancing factor. The experiments were repeated with young quail, but amyloid deposits were not observed following LPS injections. However, AA amyloidosis did develop when quail amyloid was injected in addition to LPS. These results indicated that adult quail develop AA amyloidosis after inflammatory stimulation with LPS. Furthermore, quail AA amyloidosis was shown to have transmissibility regardless of age. Interestingly, the authors found that administration of chicken amyloid fibrils also induced AA amyloidosis in young quail. This is the first report of cross-species transmission of avian AA amyloidosis.

  16. Redirecting T-Cell Specificity to EGFR Using mRNA to Self-limit Expression of Chimeric Antigen Receptor.

    PubMed

    Caruso, Hillary G; Torikai, Hiroki; Zhang, Ling; Maiti, Sourindra; Dai, Jianliang; Do, Kim-Anh; Singh, Harjeet; Huls, Helen; Lee, Dean A; Champlin, Richard E; Heimberger, Amy B; Cooper, Laurence J N

    2016-06-01

    Potential for on-target, but off-tissue toxicity limits therapeutic application of genetically modified T cells constitutively expressing chimeric antigen receptors (CARs) from tumor-associated antigens expressed in normal tissue, such as epidermal growth factor receptor (EGFR). Curtailing expression of CAR through modification of T cells by in vitro-transcribed mRNA species is one strategy to mitigate such toxicity. We evaluated expression of an EGFR-specific CAR coded from introduced mRNA in human T cells numerically expanded ex vivo to clinically significant numbers through coculture with activating and propagating cells (AaPC) derived from K562 preloaded with anti-CD3 antibody. The density of AaPC could be adjusted to affect phenotype of T cells such that reduced ratio of AaPC resulted in higher proportion of CD8 and central memory T cells that were more conducive to electrotransfer of mRNA than T cells expanded with high ratios of AaPC. RNA-modified CAR T cells produced less cytokine, but demonstrated similar cytolytic capacity as DNA-modified CAR T cells in response to EGFR-expressing glioblastoma cells. Expression of CAR by mRNA transfer was transient and accelerated by stimulation with cytokine and antigen. Loss of CAR abrogated T-cell function in response to tumor and normal cells expressing EGFR. We describe a clinically applicable method to propagate and modify T cells to transiently express EGFR-specific CAR to target EGFR-expressing tumor cells that may be used to limit on-target, off-tissue toxicity to normal tissue.

  17. Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo

    PubMed Central

    Xiao, Qi; Zhou, Yachun; Wei, Yingjie; Gong, Zhunan

    2018-01-01

    Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear. Methods In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined. Results We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling

  18. Antiangiogenic effects of AA-PMe on HUVECs in vitro and zebrafish in vivo.

    PubMed

    Jing, Yue; Wang, Gang; Xiao, Qi; Zhou, Yachun; Wei, Yingjie; Gong, Zhunan

    2018-01-01

    Angiogenesis plays a vital role in many physiological and pathological processes and several diseases are connected with its dysregulation. Asiatic acid (AA) has demonstrated anticancer properties and we suspect this might be attributable to an effect on angio-genesis. A modified derivative of AA, N-(2α,3β,23-acetoxyurs-12-en-28-oyl)-L-proline methyl ester (AA-PMe), has improved efficacy over its parent compound, but its effect on blood vessel development remains unclear. In this study, we investigated the antiangiogenic activity of AA and AA-PMe in zebrafish embryos and human umbilical vein endothelial cells (HUVECs). First of all, we treated HUVECs with increasing concentrations of AA-PMe or AA, with or without vascular endothelial growth factor (VEGF) present, and assessed cell viability, tube formation, and cell migration and invasion. Quantitative real-time polymerase chain reaction and Western blot analysis were later used to determine the role of vascular endothelial growth factor receptor 2 (VEGFR2)-mediated signaling in AA-PMe inhibition of angiogenesis. We extended these studies to follow angiogenesis using Tg(fli:EGFP) transgenic zebrafish embryos. For these experiments, embryos were treated with varying concentrations of AA-PMe or AA from 24 to 72 hours postfertilization prior to morphological observation, angiogenesis assessment, and endogenous alkaline phosphatase assay. VEGFR2 expression in whole embryos following AA-PMe treatment was also determined. We found AA-PMe decreased cell viability and inhibited migration and tube formation in a dose-dependent manner in HUVECs. Similarly, AA-PMe disrupted the formation of intersegmental vessels, the dorsal aorta, and the posterior cardinal vein in zebrafish embryos. Both in vitro and in vivo AA-PMe surpassed AA in its ability to block angiogenesis by suppressing VEGF-induced phosphorylation of VEGFR2 and disrupting downstream extracellular regulated protein kinase and AKT signaling. For the first time

  19. Fundamental Investigation of Fatigue Crack Growth Retardation in Aluminum Alloys

    DTIC Science & Technology

    1976-09-01

    Fatigue Crack Propagation in 2024 -T3 Aluminum Alloy , " ASTM STP 536, p. 115, 1973. 9. J. Schijve, " Effect of Load Sequences...Hertzberg, " Effect of Multiple Over- loads on Fatigue Crack Propagation in 2024 -T3 Aluminum Alloy , " ASTM STP-536, p. 115, 1973. 9. J. Schijve... Effect of Thickness on Retardation Behavior of 7075 and 2024 Aluminum Alloys .......... 185 vi LIST OF ILLUSTRATIONS FIGURE PAGE 1 SEN

  20. Controlled release of bioactive PDGF-AA from a hydrogel/nanoparticle composite.

    PubMed

    Elliott Donaghue, Irja; Shoichet, Molly S

    2015-10-01

    Polymer excipients, such as low molar mass poly(ethylene glycol) (PEG), have shown contradictory effects on protein stability when co-encapsulated in polymeric nanoparticles. To gain further insight into these effects, platelet-derived growth factor (PDGF-AA) was encapsulated in polymeric nanoparticles with vs. without PEG. PDGF-AA is a particularly compelling protein, as it has been demonstrated to promote cell survival and induce the oligodendrocyte differentiation of neural stem/progenitor cells (NSPCs) both in vitro and in vivo. Here we show, for the first time, the controlled release of bioactive PDGF-AA from an injectable nanoparticle/hydrogel drug delivery system (DDS). PDGF-AA was encapsulated, with high efficiency, in poly(lactide-co-glycolide) nanoparticles, and its release from the drug delivery system was followed over 21 d. Interestingly, the co-encapsulation of low molecular weight poly(ethylene glycol) increased the PDGF-AA loading but, unexpectedly, accelerated the aggregation of PDGF-AA, resulting in reduced activity and detection by enzyme-linked immunosorbent assay (ELISA). In the absence of PEG, released PDGF-AA remained bioactive as demonstrated with NSPC oligodendrocyte differentiation, similar to positive controls, and significantly different from untreated controls. This work presents a novel delivery method for differentiation factors, such as PDGF-AA, and provides insights into the contradictory effects reported in the literature of excipients, such as PEG, on the loading and release of proteins from polymeric nanoparticles. Previously, the polymer poly(ethylene glycol) (PEG) has been used in many biomaterials applications, from surface coatings to the encapsulation of proteins. In this work, we demonstrate that, unexpectedly, low molecular weight PEG has a deleterious effect on the release of the encapsulated protein platelet-derived growth factor AA (PDGF-AA). We also demonstrate release of bioactive PDGF-AA (in the absence of PEG

  1. Study of mechanical joint strength of aluminum alloy 7075-T6 and dual phase steel 980 welded by friction bit joining and weld-bonding under corrosion medium

    DOE PAGES

    Lim, Yong Chae; Squires, Lile; Pan, Tsung-Yu; ...

    2014-12-30

    We have employed a unique solid-sate joining process, called friction bit joining (FBJ), to spot weld aluminum alloy (AA) 7075-T6 and dual phase (DP) 980 steel. Static joint strength was studied in the lap shear tension configuration. In addition, weld-bonding (adhesive + FBJ) joints were studied in order to evaluate the ability of adhesive to mitigate the impact of corrosion on joint properties. Accelerated laboratory cyclic corrosion tests were carried out for both FBJ only and weld-bonding joints. Furthermore, the FBJ only joints that emerged from corrosion testing had lap shear failure loads that were significantly lower than freshly preparedmore » joints. However, weld-bonding specimens retained more than 80% of the lap shear failure load of the freshly prepared weld-bonding specimens. Moreover, examination of joint cross sections confirmed that the presence of adhesive in the weld-bonding joints mitigated the effect of the corrosion environment, compared to FBJ only joints.« less

  2. 35t Prototype Detector for Experiment at Long Base Line Neutrino Facility (ELBNF) Far Detector

    NASA Astrophysics Data System (ADS)

    Santucci, Gabriel; Elbnf Collaboration

    2015-04-01

    The 35ton prototype detector is a Liquid Argon Time Projection Chamber (LAr TPC) utilizing a membrane cryostat. It serves as a prototype for testing technology proposed for the ELBNF far detector. The construction of the prototype is an essential part of the ELBNF project due to the large amount of new technologies introduced for the far detector. In early 2014, it was shown that the membrane cryostat technology was able to reach and maintain the required LAr purity and an electron lifetime of 2.5 ms was achieved. The goals for the next phase include the installation of a fully functional TPC using the novel designs for the ELBNF far detector as much as possible. This includes the installation of the cold electronics, scintillation photon detectors and multiple Anode Plane Arrays with wrapped wires. In this talk I will review the status of the 35t prototype detector and describe what has been accomplished during 2014 and early 2015, including the commissioning phase and the early stages of data taking from cosmic-rays.

  3. Antagonistic trait of Staphylococcus succinus strain AAS2 against uropathogens and assessment of its in vitro probiotic characteristics.

    PubMed

    Khusro, Ameer; Aarti, Chirom; Salem, Abdelfattah Z M; Buendía Rodríguez, German; Rivas-Cáceres, Raymundo Rene

    2018-03-14

    The desideratum aim of the present context was to isolate a promising antagonist probiotic bacterium from fermented food item as biocontrol agent against uropathogens. Among diversified isolates evaluated for antagonistic trait, Staphylococcus succinus strain AAS2 was found to be an auspicious candidate against urinary tract infection (UTI) causing bacterial pathogens, being the most active against Staphylococcus aureus with substantial activity of 352.5 ± 5.4 AU/mL. Further, the in vitro probiotic attributes of strain AAS2 were assessed using systematic methodology. The isolate exhibited tolerance to acidic condition (up to pH 3.0) and simulated gastric juice (at pH 3.0) with fairly high survival logarithmic cell counts of 5.3 ± 0.15 and 5.23 ± 0.02 log cfu/mL, respectively. Additionally, strain AAS2 showed capability to resist 0.5% w/v bile salt too. It also revealed significant values of auto-aggregation (32.5 ± 1.3-56.5 ± 1.4%) and cell surface hydrophobicity (38.35 ± 1.4%) properties. The isolate showed resistivity towards phenol (6.8 ± 0.08 log cfu/mL) and lysozyme (58.6 ± 1.6%). Further, the susceptibility trait of strain AAS2 to conventional antibiotics made this isolate a promising probiotic bacterium. Most importantly, the isolate depicted DPPH (2,2-Diphenyl-1-picrylhydrazyl) and hydroxyl radical scavenging activities in a concentration dependent manner, thereby exhibiting its propitious antioxidative properties. In a nutshell, the outcomes of this investigation divulge the plausible use of S. succinus strain AAS2 as biocontrol agent against uropathogens, and recommended further applications in pharmaceutics due to its pronounced probiotic traits. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. SU-E-T-209: Comparison of Plan Quality Between Arm Avoidance (AA) Vs. Non Arm Avoidance VMAT Planning Techniques for Breast Cancer Patients with Bilateral Implant Reconstructions Receiving Postmastectomy Radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kuo, L; Ballangrud, A; Ho, A

    Purpose: Breast cancer patients with bilateral implant reconstructions who require postmastectomy radiotherapy can pose unique treatment planning challenges. The use of VMAT may provide advantages over conventional tangent or multi-beam IMRT techniques. Moreover, daily setup uncertainly of the arm position, however, could have significant impact on accurate dose delivery. This study compares the plan qualities between non-AA and AA VMAT techniques. Methods: Three breast cancer patients receiving left chest wall and regional nodal irradiation with bilateral implant reconstructions were studied. PTV included chest wall and IMNs (PTV-CW), and supraclavicular and axillary lymph nodes (PTV-SCV). For each patient, one non-AA VMATmore » plan (VMAT-S) with 4 partial arcs encompassing the ipsilateral arm and three AA VMAT plans where no arcs were entering or existing through the ipsilateral arm were generated. VMAT-AA1 uses 2 arcs for PTV-CW and 2 arcs for PTV-SCV. VMAT-AA2 used two static fields for PTV-SCV with 2 arcs for PTV-CW. VMAT-AA3 used 2 narrow arcs for PTV-CW and 2 long arcs for all PTVs. Prescription dose (PD) was 50 Gy (25 fractions). All plans were normalized to have 95% of PD to 95 % of PTV. PTV dose inhomogeneity and dose to the heart, left lung, right thyroid dose and left humerus were evaluated. Results: For VMAT-S, VMAT-AA1, VMAT-AA2 and VMAT-AA3, respectively, the average and standard deviation (in Gy unless specified otherwise) of PTV D05 are 54.7±0.9, 55.9±0.4, 56.7±0.7 and 55.7±0.4; mean Heart dose: 7.1±0.7, 7.2±0.8, 7.3±0.9 and 6.9±1.0; left lung V20Gy (in %): 28.1±1.0, 28.8+2.2, 32.2±4.1 and 27.8±2.0; mean right thyroid dose: 8.1±0.6, 5.1±2.1, 2.1±0.4 and 5.0±2.0; mean left humerus dose: 20.0±4.4,15.6±4.4, 15.2±8.2 and 15.3±4.6. Conclusion: AA VMAT can produce acceptable clinical plans while eliminating dosimetric impact related to arm setup uncertainty. These data require validation in larger planning studies prior to routine

  5. Comparison of ``AA`` nickel metal hydride cells with ``AA`` Ni-Cd cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alminauskas, V.; Johnson, W.

    1996-12-31

    This paper compares ``AA`` size nickel metal hydride (Ni-HM) cells with comparable ``AA;; nickel cadmium (Ni-Cd) cells both of which were obtained in 1993. The Ni-MH cells were found to be a suitable substitute for conventional Ni-Cd cells. Both these cell types have similar voltages and discharge characteristics. The Ni-MH cells, though had nearly twice the capacity as comparable Ni-Cd cells. There was no significant difference in self discharge between the two types of cells. The Ni-MH cells also performed as well as Ni-Cd cells at rates lower than 5 amperes and at temperatures higher than 0 C (32 F).more » The most interesting finding is that the Ni-MH cells showed an irreversible decay of the discharge voltage with each cycle which was more noticeable during pulses. Eventually the Ni-MH packs fail, not because of loss of capacity, but because of low voltage during the pulse.« less

  6. Inhibitory effect of propolis on the development of AA amyloidosis.

    PubMed

    Harata, Daichi; Tsuchiya, Yuya; Miyoshi, Tomoyuki; Yanai, Tokuma; Suzuki, Kazuhiko; Murakami, Tomoaki

    2018-04-01

    In the several types of amyloidoses, participation of oxidative stresses in the pathogenesis and the effect of antioxidants on amyloidosis have been reported. Meanwhile, the relationship between oxidative stresses and pathogenesis of amyloid A (AA) amyloidosis is still unclear. In this study, we used an antioxidant, Brazilian propolis, to investigate the inhibitory effects on AA amyloidosis. The results showed that AA deposition was inhibited by administration of propolis. Increased expression of antioxidant markers was detected in molecular biological examinations of mice treated with propolis. Although serum amyloid A (SAA) levels were strongly correlated with the immunoreactive area of AA deposits in the control group, the correlation was weaker in the propolis-treated groups. In addition, there were no changes in SAA levels between the control group and the propolis-treated groups. The results indicate that propolis, an antioxidant, may induce inhibitory effects against AA amyloidosis.

  7. Phage display antibodies against ectromelia virus that neutralize variola virus: Selection and implementation for p35 neutralizing epitope mapping.

    PubMed

    Khlusevich, Yana; Matveev, Andrey; Baykov, Ivan; Bulychev, Leonid; Bormotov, Nikolai; Ilyichev, Ivan; Shevelev, Georgiy; Morozova, Vera; Pyshnyi, Dmitrii; Tikunova, Nina

    2018-04-01

    In this study, five phage display antibodies (pdAbs) against ectromelia virus (ECTV) were selected from vaccinia virus (VACV)-immune phage-display library of human single chain variable fragments (scFv). ELISA demonstrated that selected pdAbs could recognize ECTV, VACV, and cowpox virus (CPXV). Atomic force microscopy visualized binding of the pdAbs to VACV. Three of the selected pdAbs neutralized variola virus (VARV) in the plaque reduction neutralization test. Western blot analysis of ECTV, VARV, VACV, and CPXV proteins indicated that neutralizing pdAbs bound orthopoxvirus 35 kDa proteins, which are encoded by the open reading frames orthologous to the ORF H3L in VACV. The fully human antibody fh1A was constructed on the base of the VH and VL domains of pdAb, which demonstrated a dose-dependent inhibition of plaque formation after infection with VARV, VACV, and CPXV. To determine the p35 region responsible for binding to neutralizing pdAbs, a panel of truncated p35 proteins was designed and expressed in Escherichia coli cells, and a minimal p35 fragment recognized by selected neutralizing pdAbs was identified. In addition, peptide phage-display combinatorial libraries were applied to localize the epitope. The obtained data indicated that the epitope responsible for recognition by the neutralizing pdAbs is discontinuous and amino acid residues located within two p35 regions, 15-19 aa and 232-237 aa, are involved in binding with neutralizing anti-p35 antibodies. Copyright © 2018. Published by Elsevier B.V.

  8. Exposure to Melan-A/MART-126-35 tumor epitope specific CD8+T cells reveals immune escape by affecting the ubiquitin-proteasome system (UPS)

    PubMed Central

    Ebstein, Frédéric; Keller, Martin; Paschen, Annette; Walden, Peter; Seeger, Michael; Bürger, Elke; Krüger, Elke; Schadendorf, Dirk; Kloetzel, Peter-M.; Seifert, Ulrike

    2016-01-01

    Efficient processing of target antigens by the ubiquitin-proteasome-system (UPS) is essential for treatment of cancers by T cell therapies. However, immune escape due to altered expression of IFN-γ-inducible components of the antigen presentation machinery and consequent inefficient processing of HLA-dependent tumor epitopes can be one important reason for failure of such therapies. Here, we show that short-term co-culture of Melan-A/MART-1 tumor antigen-expressing melanoma cells with Melan-A/MART-126-35-specific cytotoxic T lymphocytes (CTL) led to resistance against CTL-induced lysis because of impaired Melan-A/MART-126-35 epitope processing. Interestingly, deregulation of p97/VCP expression, which is an IFN-γ-independent component of the UPS and part of the ER-dependent protein degradation pathway (ERAD), was found to be essentially involved in the observed immune escape. In support, our data demonstrate that re-expression of p97/VCP in Melan-A/MART-126-35 CTL-resistant melanoma cells completely restored immune recognition by Melan-A/MART-126-35 CTL. In conclusion, our experiments show that impaired expression of IFN-γ-independent components of the UPS can exert rapid immune evasion of tumor cells and suggest that tumor antigens processed by distinct UPS degradation pathways should be simultaneously targeted in T cell therapies to restrict the likelihood of immune evasion due to impaired antigen processing. PMID:27143649

  9. Effect of SMAT on microstructural and mechanical properties of AA2024

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tadge, Prashant, E-mail: prashant-tadge@rediffmail.com; Sasikumar, C., E-mail: csasimv@gmail.com

    In recent days surface mechanical attrition treatment (SMAT) had attracted the attention of researchers as it produces a nano-crystalline surface with improved mechanical properties. In the present study Al-4%Cu alloy used in automobile and aerospace application is subjected to surface mechanical attrition treatment using steel shots. The microstructural changes introduced on the surface of the Al alloy was investigated using Scanning Electron Microscopy (SEM). The secondary phases formed during the SMAT process is been investigated using EDX and XRD analysis. The effects of SMAT on the mechanical properties were analyzed using a tensile testing. The SMA treatment had resulted inmore » severe plastic deformation of the surface, thereby yielded a nanocrystalline surface with a grain size of 30 to 50 nm. Further, it is also found that the SMAT produced ultra nanocrystalline particles of Cu{sub 2}Al dispersed uniformly into α-Al matrix. These microstructural changes had resulted in considerable change in the mechanical properties of these alloys. The tensile strength of these alloys had increased from ∼212 MPa to 303 MPa while the fracture toughness increased up to 28% in 10 minutes of SMAT.« less

  10. Effect of SMAT on microstructural and mechanical properties of AA2024

    NASA Astrophysics Data System (ADS)

    Tadge, Prashant; Sasikumar, C.

    2016-05-01

    In recent days surface mechanical attrition treatment (SMAT) had attracted the attention of researchers as it produces a nano-crystalline surface with improved mechanical properties. In the present study Al-4%Cu alloy used in automobile and aerospace application is subjected to surface mechanical attrition treatment using steel shots. The microstructural changes introduced on the surface of the Al alloy was investigated using Scanning Electron Microscopy (SEM). The secondary phases formed during the SMAT process is been investigated using EDX and XRD analysis. The effects of SMAT on the mechanical properties were analyzed using a tensile testing. The SMA treatment had resulted in severe plastic deformation of the surface, thereby yielded a nanocrystalline surface with a grain size of 30 to 50 nm. Further, it is also found that the SMAT produced ultra nanocrystalline particles of Cu2Al dispersed uniformly into α-Al matrix. These microstructural changes had resulted in considerable change in the mechanical properties of these alloys. The tensile strength of these alloys had increased from ˜212 MPa to 303 MPa while the fracture toughness increased up to 28% in 10 minutes of SMAT.

  11. Duplication of Drosophila melanogaster mitochondrial EF-Tu: pre-adaptation to T-arm truncation and exclusion of bulky aminoacyl residues.

    PubMed

    Sato, Aya; Suematsu, Takuma; Aihara, Koh-Ki; Kita, Kiyoshi; Suzuki, Tsutomu; Watanabe, Kimitsuna; Ohtsuki, Takashi; Watanabe, Yoh-Ichi

    2017-03-07

    Translation elongation factor Tu (EF-Tu) delivers aminoacyl-tRNA (aa-tRNA) to ribosomes in protein synthesis. EF-Tu generally recognizes aminoacyl moieties and acceptor- and T-stems of aa-tRNAs. However, nematode mitochondrial (mt) tRNAs frequently lack all or part of the T-arm that is recognized by canonical EF-Tu. We previously reported that two distinct EF-Tu species, EF-Tu1 and EF-Tu2, respectively, recognize mt tRNAs lacking T-arms and D-arms in the mitochondria of the chromadorean nematode Caenorhabditis elegans C. elegans EF-Tu2 specifically recognizes the seryl moiety of serylated D-armless tRNAs. Mitochondria of the enoplean nematode Trichinella possess three structural types of tRNAs: T-armless tRNAs, D-armless tRNAs, and cloverleaf tRNAs with a short T-arm. Trichinella mt EF-Tu1 binds to all three types and EF-Tu2 binds only to D-armless Ser-tRNAs, showing an evolutionary intermediate state from canonical EF-Tu to chromadorean nematode (e.g. C. elegans ) EF-Tu species. We report here that two EF-Tu species also participate in Drosophila melanogaster mitochondria. Both D. melanogaster EF-Tu1 and EF-Tu2 bound to cloverleaf and D-armless tRNAs. D. melanogaster EF-Tu1 has the ability to recognize T-armless tRNAs that do not evidently exist in D. melanogaster mitochondria, but do exist in related arthropod species. In addition, D. melanogaster EF-Tu2 preferentially bound to aa-tRNAs carrying small amino acids, but not to aa-tRNAs carrying bulky amino acids. These results suggest that the Drosophila mt translation system could be another intermediate state between the canonical and nematode mitochondria-type translation systems. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  12. Good outcome rate of 35% in IV-tPA-treated patients with computed tomography angiography confirmed severe anterior circulation occlusive stroke.

    PubMed

    González, R Gilberto; Furie, Karen L; Goldmacher, Gregory V; Smith, Wade S; Kamalian, Shervin; Payabvash, Seyedmehdi; Harris, Gordon J; Halpern, Elkan F; Koroshetz, Walter J; Camargo, Erica C S; Dillon, William P; Lev, Michael H

    2013-11-01

    To determine the effect of intravenous tissue plasminogen activator (IV-tPA) on outcomes in patients with severe major anterior circulation ischemic stroke. Prospectively, 649 patients with acute stroke had admission National Institutes of Health stroke scale (NIHSS) scores, noncontrast computed tomography (CT), CT angiography (CTA), and 6-month outcome assessed using modified Rankin scale. IV-tPA treatment decisions were made before CTA, at the time of noncontrast CT scanning, as per routine clinical protocol. Severe symptoms were defined as NIHSS>10. Poor outcome was defined as modified Rankin scale >2. Major occlusions were identified on CTA. Univariate and multivariate stepwise-forward logistic regression analyses of the full cohort were performed. Of 649 patients, 188 (29%) patients presented with NIHSS>10, and 64 out of 188 (34%) patients received IV-tPA. Admission NIHSS, large artery occlusion, and IV-tPA all independently predicted good outcomes; however, a significant interaction existed between IV-tPA and occlusion (P<0.001). Of the patients who presented with NIHSS>10 with anterior circulation occlusion, twice the percentage had good outcomes if they received IV-tPA (17 out of 49 patients, 35%) than if they did not (13 out of 77 patients, 17%; P=0.031). The number needed to treat was 7 (95% confidence interval, 3-60). IV-tPA treatment resulted in significantly better outcomes in patients with severely symptomatic stroke with major anterior circulation occlusions. The 35% good outcome rate was similar to rates found in endovascular therapy trials. Vascular imaging may help in patient selection and stratification for trials of IV-thrombolytic and endovascular therapies.

  13. Introducing the AAS Astronomy Ambassadors Program

    NASA Astrophysics Data System (ADS)

    Gurton, S.; Fienberg, R. T.; Fraknoi, A.; Prather, E. E.

    2013-04-01

    Newly established by the American Astronomical Society (AAS), the Astronomy Ambassadors program is designed to support early-career AAS members with training in resources and techniques for effective outreach to students and/or the public. A pilot Astronomy Ambassadors workshop will be held at the January 2013 AAS meeting. Workshop participants will learn to communicate effectively with public and school audiences; find outreach opportunities and establish ongoing partnerships with local schools, science centers, museums, parks, and/or community centers; reach audiences with personal stories, hands-on activities, and jargon-free language; identify strategies and techniques to improve their presentation skills; gain access to a menu of outreach resources that work in a variety of settings; and become part of an active community of astronomers who do outreach. Applications are welcome from advanced undergraduates (those doing research and committed to continuing in astronomy), graduate students, and postdocs and new faculty in their first two years after receipt of the PhD. We especially encourage applications from members of groups that are presently underrepresented in science.

  14. Detection of t(3;5) and NPM1/MLF1 rearrangement in an elderly patient with acute myeloid leukemia: clinical and laboratory study with review of the literature.

    PubMed

    Lim, Gayoung; Choi, Jong Rak; Kim, Min Jin; Kim, So Young; Lee, Hee Joo; Suh, Jin-Tae; Yoon, Hwi-Joong; Lee, Juhie; Lee, Sanggyu; Lee, Woo-In; Park, Tae Sung

    2010-06-01

    We present a novel case of acute myeloid leukemia with an NPM1/MLF1 rearrangement in a 78-year-old Korean woman. The bone marrow chromosome study showed a complex karyotype: 46,XX,t(2;13) (q13;q32),der(3)t(3;5)(q25.1;q34),der(5)del(5)(?q31q34)t(3;5),inv(9)(p11q13)c,del(20)(q11.2)[13]/49,idem,+5,+8,+der(13)t(2;13)[7]. Multiplex gene rearrangement testing, cloning, and sequencing analyses revealed an NPM1/MLF1 fusion rearrangement between exon 6 of NPM1 (ENSG00000181163) and exon 2 of MLF1 (ENSG00000178053). Although t(3;5)(q25.1;q34) or the NPM1/MLF1 rearrangement has been reported mostly as a sole karyotypic abnormality in younger patients, it should also be considered in elderly patients with complex chromosomal abnormalities in acute myeloid leukemia or myelodysplastic syndrome. Copyright 2010 Elsevier Inc. All rights reserved.

  15. Bacillus thuringiensis Cry3Aa protoxin intoxication of Tenebrio molitor induces widespread changes in the expression of serine peptidase transcripts.

    PubMed

    Oppert, Brenda; Martynov, Alexander G; Elpidina, Elena N

    2012-09-01

    The yellow mealworm, Tenebrio molitor, is a pest of stored grain products and is sensitive to the Bacillus thuringiensis (Bt) Cry3Aa toxin. As digestive peptidases are a determining factor in Cry toxicity and resistance, we evaluated the expression of peptidase transcripts in the midgut of T. molitor larvae fed either a control or Cry3Aa protoxin diet for 24 h (RNA-Seq), or in larvae exposed to the protoxin for 6, 12, or 24 h (microarrays). Cysteine peptidase transcripts (9) were similar to cathepsins B, L, and K, and their expression did not vary more than 2.5-fold in control and Cry3Aa-treated larvae. Serine peptidase transcripts (48) included trypsin, chymotrypsin and chymotrypsin-like, elastase 1-like, and unclassified serine peptidases, as well as homologs lacking functional amino acids. Highly expressed trypsin and chymotrypsin transcripts were severely repressed, and most serine peptidase transcripts were expressed 2- to 15-fold lower in Cry3Aa-treated larvae. Many serine peptidase and homolog transcripts were found only in control larvae. However, expression of a few serine peptidase transcripts was increased or found only in Cry3Aa-treated larvae. Therefore, Bt intoxication significantly impacted the expression of serine peptidases, potentially important in protoxin processing, while the insect maintained the production of critical digestive cysteine peptidases. Published by Elsevier Inc.

  16. Outcomes From AAS Hack Day at the 227th AAS Meeting

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Editors Note:This is a final post from the 227th AAS Meeting in Kissimmee, FL. This special summary of AAS Hack Day, a meeting of AAS members to collaboratively work on various small projects, was written by Meredith Rawls (@Merrdiff) and was originally posted on astrobites.com.As the 227thAmerican Astronomical Society meeting drew to a close (see highlights from Day 1, Day 2, Day 3, and Day 4), a group of at least 50 attendees spent Day 4working on small projects fondly called hacks. Thanks to sponsorship from LSST and Northrup Grumman, the industrious hackers werewell-caffeinated and fed so we could devote time and energy toworking in groups on one-day projects.TheHack Day beganat 10am with pitches. Anybody with a project idea was welcome to briefly speak and try to convince others to work with them. Only someideas panned out, but the enthusiasm was palpable. Its not every day you get a full room of astronomers and affiliates eager to spend hours working on fun and useful projects to benefit the community.#hackAAS is getting underway! #aas227 pic.twitter.com/yX7jlOnSCK James R A Davenport (@jradavenport) January 8, 2016Here is a rundown of what we accomplished. Pretty impressive for a single day! Many thanks to fellow astrobiter Erika Nesvold (now at Carnegie DTM; @erikanesvold) whose hack was live-documenting all the other hacks. Her tweets as @astrobites appeared with the #hackaas hashtag, and her notes made this recap post infinitely easier to write.Interested in joining the fun? Sign up for Hack Day at the 2017 JanuaryAAS meeting (its free with meeting registration), and consider applying for the .Astronomy conference this summer.Towards Optimal Session Scheduling:Adrian Price-Whelan (Columbia), David Hogg (NYU), and Scott Idem (AAS) began writing a program to take all submitted abstracts to a conference like AAS and sort them using keywords to avoid scheduling similar talks in parallel sessions. Its impossible to make everyone happy, but minimizing conflicts

  17. 26 CFR 35.3405-1T - Questions and answers relating to withholding on pensions, annuities, and certain other deferred...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... payment for the year? A. No. Periodic payments can vary during a calendar year because of make-up of past... 26 Internal Revenue 15 2010-04-01 2010-04-01 false Questions and answers relating to withholding... REGULATIONS UNDER THE TAX EQUITY AND FISCAL RESPONSIBILITY ACT OF 1982 § 35.3405-1T Questions and answers...

  18. Early acute myeloblastic leukemia treatment for childhood myelodysplastic syndrome with t(3;5) (NPM/MLF1).

    PubMed

    Sevilla, Julián; Fernández-Plaza, Sandra; Lassaletta, Alvaro; González-Vicent, Marta; Contra, Trinidad; Madero, Luis

    2007-12-01

    Myelodysplastic syndromes (MDS) in childhood are rare hematologic diseases. MDS with t(3;5) (NPM/MLF1) is an unusual subtype without a well-defined clinical and prognostic pattern. A poor outcome has been reported, suggesting that hematopoietic transplantation is the only treatment option. Here in we described a 2-year-old child diagnosed with the disease, without a suitable hematopoietic donor, treated early in the disease with chemotherapy. He is alive and well 4 years after the end of treatment. This unusual MDS needs further studies to better understand the disease.

  19. The Fourth Joint Meeting of the AAS and ASP, Victoria, June 1952

    NASA Astrophysics Data System (ADS)

    Garstang, R. H.

    1999-05-01

    This meeting was my most memorable because (1) it was the first AAS meeting to be held in Western Canada, (2) it was my first visit to Canada, (3) it was the occasion of the dedication of the Dominion Astrophysical Observatory 72-inch telescope to the memory of J. S. Plaskett, in the presence of Mrs. Plaskett, (4) there was a special symposium on emission line stars, which included a lecture by Paul Merrill to celebrate his retirement, and C. S. Beals and J. A. Rottenberg as the other main speakers, (5) Robert McMath gave the first Aitken lecture in memory of the famous double star astronomer, (6) I was elected a member of the AAS by the Council at this meeting, (7) I was already a member of the ASP, and this was my first opportunity to present a paper at an ASP meeting, and I could choose to put my abstract in the P.A.S.P., (8) I met many astronomers there who have been friends ever since, (9) along with many attendees I visited Butchart's Gardens, and (10) there was an excellent banquet at the Empress Hotel.

  20. DEVELOPMENTAL AND WITHDRAWAL EFFECTS OF ADOLESCENT AAS EXPOSURE ON THE GLUTAMATERGIC SYSTEM IN HAMSTERS

    PubMed Central

    Carrillo, Maria; Ricci, Lesley A.; Melloni, Richard H.

    2011-01-01

    In the Syrian hamster (Mesocricetus auratus) glutamate activity has been implicated in the modulation of adolescent anabolic-androgenic steroid (AAS)-induced aggression. The current study investigated the time course of adolescent AAS-induced neurodevelopmental and withdrawal effects on the glutamatergic system and examined whether these changes paralleled those of adolescent AAS-induced aggression. Glutamate activity in brain areas comprising the aggression circuit in hamsters and aggression were examined following 1, 2, 3 and 4 weeks of AAS treatment or 1, 2, 3 and 4 weeks following the cessation of AAS exposure. In these studies glutamate activity was examined using vesicular glutamate transporter 2 (VGLUT2). The onset of aggression was observed following 2 weeks exposure to AAS and continued to increase showing maximal aggression levels after 4 weeks of AAS treatment. This aggressive phenotype was detected after 2 weeks of withdrawal from AAS. The time-course of AAS-induced changes in latero anterior hypothalamus (LAH)-VGLUT2 closely paralleled increases in aggression. Increases in LAH-VGLUT2 were first detected in animals exposed to AAS for 2 weeks and were maintained up to 3 weeks following the cessation of AAS treatment. AAS treatment also produced developmental and long-term alterations in VGLUT2 expression within other aggression areas. However, AAS-induced changes in glutamate activity within these regions did not coincide with changes in aggression. Together, these data indicate that adolescent AAS treatment leads to alterations in the glutamatergic system in brain areas implicated in aggression control, yet only alterations in LAH-glutamate parallel the time course of AAS-induced changes in the aggressive phenotype. PMID:21500881

  1. Cloning and characterization of microbial activated Aedes aegypti MEK4 (AaMEK4): influences of noncatalytic domains on enzymatic activity.

    PubMed

    Wu, R C-C; Cho, W-L

    2014-10-01

    Protein kinases are known to be involved in a number of signal transduction cascades. Both the stress-activated Jun N-terminal kinase (JNK) and mitogen-activated protein kinase (MAPK) p38 pathways have been shown to correlate with the insect immune response to microbial infection. MAP kinase kinase 4 (MEK4) is an upstream kinase of JNK and p38 kinase. The cDNA of AaMEK4 was cloned and characterized. AaMEK4 was activated by microbial lysates of Gram-positive, Gram-negative bacteria and yeast. The conserved lysine (K112 ) and the putative phosphorylation sites (S238 and T242 ) were shown to be important for kinase activity by site-directed mutagenesis. A common MAPK docking site (MAPK_dsA) was found and in addition, a new nearby docking site, MAPK_dsB, was identified in the N-terminal noncatalytic domain of AaMEK4. MAPK_dsB was shown to be a unique element in the MEK4 family. In this study, both MAPK_dsA and _dsB were demonstrated to be important to AaMEK4 enzymatic activity for the downstream protein kinase, Aap38. © 2014 The Royal Entomological Society.

  2. Mechanical Characteristics of Welded Joints of Aluminum Alloy 6061 T6 Formed by Arc and Friction Stir Welding

    NASA Astrophysics Data System (ADS)

    Astarita, A.; Squillace, A.; Nele, L.

    2016-01-01

    Butt welds formed by arc welding in inert gas with nonconsumable electrode (tungsten inert gas (TIG) welding) and by friction stir welding (FSW) from aluminum alloy AA6061 T6 are studied. Comparative analysis of the structures and mechanical properties of the welded joints is performed using the results of optical and electron microscopy, tensile tests, tests for residual bending ductility, and measurements of microhardness. The changes in the microstructure in different zones and the degrees of degradation of the mechanical properties after the welding are determined. It is shown that the size of the tool for the friction stir welding affects the properties of the welds. Quantitative results showing the relation between the microscopic behavior of the alloy and the welding-induced changes in the microstructure are obtained. Friction stir welding is shown to provide higher properties of the welds.

  3. Characterization of hepatitis B virus surface antigen variability and impact on HBs antigen clearance under nucleos(t)ide analogue therapy.

    PubMed

    Velay, A; Jeulin, H; Eschlimann, M; Malvé, B; Goehringer, F; Bensenane, M; Frippiat, J-P; Abraham, P; Ismail, A M; Murray, J M; Combet, C; Zoulim, F; Bronowicki, J-P; Schvoerer, E

    2016-05-01

    For hepatitis B virus (HBV)-related chronic infection under treatment by nucleos(t)ide analogues (NUCs), HBsAg clearance is the ultimate therapeutic goal but very infrequent. We investigated how HBV envelope protein variability could lead to differential HBsAg clearance on NUCs. For 12 HBV genotype D patients receiving NUCs, six resolvers (HBsAg clearance) were compared to six matched nonresolvers (HBsAg persistence). PreS/S amino acid (aa) sequences were analysed with bioinformatics to predict HBV envelope antigenicity and aa covariance. To enrich our analyses on very rare resolvers, these were compared with other HBV genotype D strains in three characterized clinical cohorts including common chronically infected patients. The sT125M+sP127T combination was observed in four nonresolvers of six, corroborated by aa covariance analysis, associated with a lower predicted antigenicity than sT125T+sP127P. Concordant features within this HBV key functional domain, at positions 125 and 127, were reported from two of the three comparative cohorts. In our hands, a lower ELISA reactivity of HBV-vaccinated mice sera was observed against the sT125M mutant. In the S gene, 56 aa changes in minor variants were detected in non-resolvers, mainly in the major hydrophilic region, vs 28 aa changes in resolvers. Molecular features in patients showing HBsAg persistence on NUCs argue in favour of a different aa pattern in the HBV S gene compared to those showing HBsAg clearance. In nonresolvers, a decrease in HBs 'a' determinant antigenicity and more frequent mutations in the S gene suggest a role for the HBV envelope characteristics in HBsAg persistence. © 2016 John Wiley & Sons Ltd.

  4. Chemically activated nanodiamonds for aluminum alloy corrosion protection and monitoring

    NASA Astrophysics Data System (ADS)

    Hannstein, Inga; Adler, Anne-Katrin; Lapina, Victoria; Osipov, Vladimir; Opitz, Jörg; Schreiber, Jürgen; Meyendorf, Norbert

    2009-03-01

    In the present study, a smart coating for light metal alloys was developed and investigated. Chemically activated nanodiamonds (CANDiT) were electrophoretically deposited onto anodized aluminum alloy AA2024 substrates in order to increase corrosion resistance, enhance bonding properties and establish a means of corrosion monitoring based on the fluorescence behavior of the particles. In order to create stable aqueous CANDiT dispersions suitable for electrophoretic deposition, mechanical milling had to be implemented under specific chemical conditions. The influence of the CANDiT volume fraction and pH of the dispersion on the electrochemical properties of the coated samples was investigated. Linear voltammetry measurements reveal that the chemical characteristics of the CANDiT dispersion have a distinct influence on the quality of the coating. The fluorescence spectra as well as fluorescence excitation spectra of the samples show that corrosion can be easily detected by optical means. Furthermore, an optimization on the basis of "smart" - algorithms for the data processing of a surface analysis by the laser-speckle-method is presented.

  5. Comet Kohoutek, The Arab Oil Embargo, and the Jan 1974 AAS Meeting

    NASA Astrophysics Data System (ADS)

    Duncan, D. K.

    1999-05-01

    An unlikely combination of factors, including Comet Kohoutek and the Arab Oil embargo, combined to make my first AAS Meeting my most memorable. Three young graduate students confronted lack of gas, lack of money, and lack of planning to attend the Jan 1974 meeting in Tucson, AZ. One, Steve Hawley, displayed skills which would later be valuable when he became the astronaut who launched HST. Although we became stranded in the desert, two of the three of us made it to the meeting, and only one didn't....

  6. IL-35-producing B cells in gastric cancer patients.

    PubMed

    Wang, Ke; Liu, Jianming; Li, Jiansheng

    2018-05-01

    A significant characteristic of advanced gastric cancer (GC) is immune suppression, which can promote the progression of GC. Interleukin 35 (IL-35) is an immune-suppressing cytokine, and it is generally recognized that this cytokine is secreted by regulatory T (Treg) cells. Recently, studies have found that IL-35 can also be produced by B cells in mice. However, scientific studies reporting that IL-35 is secreted by B cells in humans, specifically in cancer patients, are very rare.Blood samples were collected from 30 healthy controls (HCs) and 50 untreated GC patients, and IL-35-producing B cells in the peripheral blood were investigated. Moreover, Treg cells (CD4CD25CD127), myeloid-derived suppressor cells (MDSCs) (CD14HLA-DR) and other lymphocyte subsets (CD3, CD4, CD8 T cells, activated and memory CD4 T cells, activated CD8 T cells, CD14 monocytes, and IL-10-producing B cells) were also examined.IL-35-producing B cells were significantly upregulated in patients with advanced GC. Furthermore, the frequency of IL-35-producing B cells was positively correlated with the frequencies of Treg cells (CD4CD25CD127), MDSCs (CD14HLA-DR), IL-10-producing B cells, and CD14 monocytes in these GC patients.In summary, the frequency of IL-35-producing B cells is significantly elevated in advanced GC; this outcome implies that this group of B cells may participate in GC progression.

  7. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

  8. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

  9. 40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

  10. A biomarker-responsive T2ex MRI contrast agent.

    PubMed

    Daryaei, Iman; Randtke, Edward A; Pagel, Mark D

    2017-04-01

    This study investigated a fundamentally new type of responsive MRI contrast agent for molecular imaging that alters T 2 exchange (T 2ex ) properties after interacting with a molecular biomarker. The contrast agent Tm-DO3A-oAA was treated with nitric oxide (NO) and O 2 . The R 1 and R 2 relaxation rates of the reactant and product were measured with respect to concentration, temperature, and pH. Chemical exchange saturation transfer (CEST) spectra of the reactant and product were acquired using a 7 Tesla (T) MRI scanner and analyzed to estimate the chemical exchange rates and r 2ex relaxivities. The reaction of Tm-DO3A-oAA with NO and O 2 caused a 6.4-fold increase in the r 2 relaxivity of the agent, whereas r 1 relaxivity remained unchanged, which demonstrated that Tm-DO3A-oAA is a responsive T 2ex agent. The effects of pH and temperature on the r 2 relaxivities of the reactant and product supported the conclusion that the product's benzimidazole ligand caused the agent to have a fast chemical exchange rate relative to the slow exchange rate of the reactant's ortho-aminoanilide ligand. T 2ex MRI contrast agents are a new type of responsive agent that have good detection sensitivity and specificity for detecting a biomarker, which can serve as a new tool for molecular imaging. Magn Reson Med 77:1665-1670, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  11. AA amyloidosis: Mount Sinai experience, 1997-2012.

    PubMed

    Bunker, Daniel; Gorevic, Peter

    2012-01-01

    AA amyloidosis is a systemic disease characterized by the extracellular deposition of amyloid fibrils derived from the acute-phase reactant serum amyloid A protein. It is typically a consequence of chronic inflammatory conditions like rheumatoid arthritis or Crohn's disease, although more patients are being identified who have more unusual causes or no known inflammatory stimulus. We performed a retrospective chart review of all patients with AA amyloidosis seen at Mount Sinai during the period of 1997-2012. Particular attention was paid to the patients' underlying diseases, extent of organ involvement, levels of inflammatory markers and proinflammatory cytokines, presence of pyrin gene mutations, and outcomes. Forty-three patients were seen at Mount Sinai with AA amyloidosis during this period. The most common underlying diseases were rheumatoid arthritis (21%) and Crohn's disease (16%), though 21% of patients were considered to have idiopathic AA amyloid after an extensive search found no underlying inflammatory disease. Almost all patients (95%) had renal involvement based on biopsy or clinical criteria, with 19 patients (44%) eventually requiring dialysis and 5 (12%) undergoing renal transplantation. Inflammatory markers were elevated in most patients; however, interleukin-6 was the only consistently elevated cytokine. Three patients (of 9 tested) were found to be positive for the E148Q pyrin gene mutation. Our study confirms the increasing number of patients being seen with idiopathic AA amyloidosis. More research is needed to determine if these patients have an underlying genetic susceptibility encoded in pyrin or other genes. Our study also confirms the dominance of renal disease in this population. The elevated levels of interleukin-6, in comparison with other cytokines, could represent a therapeutic target. © 2012 Mount Sinai School of Medicine.

  12. AAS 228: Day 3 afternoon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    ?).Peebles: expect surprises and think outside the box yes! #aas228 Kevin Schawinski (@kevinschawinski) June 15, 2016His comparison of local vs. high-redshift cosmology in terms of scales of problems was outstanding, and he encouraged the audience and the community to keep an open mind. After all, in Sean Carrolls words, we do live in a preposterous universe, and the time is almost right to explain it all.This The Limits of Scientific Cosmology series at #aas228 has been absolutely fantastic. @AAS_Office please put videos on youtube! Kevin Schawinski (@kevinschawinski) June 15, 2016Press Conference Black Holes and Gamma-Ray Bursts (by Susanna Kohler)The final press conference of the meeting covered three topics from the categories of black holes and gamma-ray bursts.Fred Rasio (CIERA/Northwestern University) opened the conference with a discussion of how the systems that LIGO detected might have formed. There are two primary models for how these black-hole binaries are created. In the first, they start out as binary systems of two massive stars. If the binary survives the process of both stars collapsing into black holes, then a binary black hole system results.Rasio focused on the second theory, in which that black holes are formed in dense stellar clusters. These black holes then sink (via dynamical friction) to the centers of the clusters like dust particles settling on the floor of a room, where they form binaries in a black hole mosh pit eventually getting kicked out of the cluster by dynamical interactions. You can read more about their research in the press release here.Rasio presents a pretty awesome animation of this black hole mosh pit. https://t.co/AkewctI7uK#aas228 astrobites (@astrobites) June 15, 2016The effects of a spinning black hole on the spacetime around it. [J.P. Eekels J.M. Overduin]Next up was Richard Henry (Johns Hopkins University), who spoke about the internal structure of spinning black holes (known as Kerr black holes). Because no light can escape from

  13. The effect of heat treatment on microstructure evolution in artificially aged carbon nanotube/Al2024 composites synthesized by mechanical alloying

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pérez-Bustamante, R.

    Although carbon nanotubes/aluminum (CNT/Al) composites are promising materials in the production of structural components, their mechanical behavior under overaging conditions has not been considered. In this paper the effect of CNTs on the microstructural and mechanical behavior of a 2024 aluminum alloy (Al2024) synthesized by mechanical alloying (MA) and powder metallurgy routes is discussed, as well as the effect of aging heat treatments at different temperatures and aging times. The mechanical behavior of composites was screened by hardness measurements as function of aging time. After 96 h of aging time, composites showed mechanical stability in their hardness performance. Images frommore » transmission electron microscopy showed that the mechanical stability of composites was due to a homogeneous dispersion of CNTs in the aluminum matrix and a subsequent alteration in the kinetics of precipitation is due to their presence in the aluminum matrix. Even though strengthening precipitation took place during aging, this was not the main strengthening mechanism observed in composites. - Highlights: • Dispersion of carbon nanotubes during mechanical alloying • Microstructural evolution observed by HRTEM. • Mechanical performance evaluated through micro-hardness test. • Increased mechanical performance at high working temperatures • Acceleration of kinetics of precipitation due to CNTs, and milling conditions.« less

  14. Metabolomic Profiling of Amino Acids and β-Cell Function Relative to Insulin Sensitivity in Youth

    PubMed Central

    Michaliszyn, Sara F.; Sjaarda, Lindsey A.; Mihalik, Stephanie J.; Lee, SoJung; Bacha, Fida; Chace, Donald H.; De Jesus, Victor R.; Vockley, Jerry

    2012-01-01

    Context: In longitudinal studies of adults, elevated amino acid (AA) concentrations predicted future type 2 diabetes mellitus (T2DM). Objective: The aim of the present investigation was to examine whether increased plasma AA concentrations are associated with impaired β-cell function relative to insulin sensitivity [i.e. disposition index (DI)], a predictor of T2DM development. Design, Setting, and Participants: Metabolomic analysis for fasting plasma AAs was performed by tandem mass spectrometry in 139 normal-weight and obese adolescents with and without dysglycemia. First-phase insulin secretion was evaluated by a hyperglycemic (∼225 mg/dl) clamp and insulin sensitivity by a hyperinsulinemic-euglycemic clamp. DI was calculated as the product of first-phase insulin and insulin sensitivity. Results: DI was positively associated with branched-chain AAs (leucine/isoleucine and valine; r = 0.27 and 0.29, P = 0.001), neutrally transported AAs (phenylalanine and methionine; r = 0.30 and 0.35, P < 0.001), basic AAs (histidine and arginine; r = 0.28 and 0.23, P ≤ 0.007), serine (r = 0.35, P < 0.001), glycine (r = 0.26, P = 0.002), and branched-chain AAs-derived intermediates C3, C4, and C5 acylcarnitine (range r = 0.18–0.19, P ≤ 0.04). Conclusion: In youth, increased plasma AA concentrations are not associated with a heightened metabolic risk profile for T2DM; rather, they are positively associated with β-cell function relative to insulin sensitivity. These contrasting observations between adults and youth may be a reflection of developmental differences along the lifespan dependent on the combined impact of the aging process together with the impact of progressive obesity. PMID:22977272

  15. Role and mechanism of AT1-AA in the pathogenesis of HELLP syndrome.

    PubMed

    Bu, Shurui; Wang, Yuxian; Sun, Shuqing; Zheng, Yanqian; Jin, Zhu; Zhi, Jianming

    2018-01-10

    HELLP syndrome remains a leading cause of maternal and neonatal mortality and morbidity worldwide, which symptoms include hemolysis, elevated liver enzymes and low platelet count. The objective of this study was to determine whether HELLP is associated with AT1-AA. The positive rate and titer of AT1-AA in plasma from pregnant women were determined, and the correlation of AT1-AA titer with the grade of HELLP was analyzed. A HELLP rat model established by intravenous injection of AT1-AA. Our experimental results show the AT1-AA titer and positive rate were significantly higher in HELLP group, and AT1-AA titer were positively correlated with the level of TNF-α and ET-1 in plasma and the grade of HELLP syndrome. The results of animal experiments showed that the typical features of HELLP in the pregnant rats after AT1-AA injection. The levels of TNF-α and ET-1 in plasma and liver tissue were significantly increased in AT1-AA-treated rats compared with control rats. The HELLP syndrome induced by AT1-AA was attenuated markedly after administration of losartan. These data support the hypothesis that one the potential pathway that AT1-AA induce damage to capillary endothelial cells and liver during pregnancy is through activation of TNF-α and ET-1.

  16. Mars 2024/2026 Pathfinder Mission: Mars Architectures, Systems, and Technologies for Exploration and Resources Project

    NASA Technical Reports Server (NTRS)

    Zeitlin, Nancy; Mueller, Robert; Muscatello, Anthony

    2015-01-01

    Integrate In Situ Resource Utilization (ISRU) sub-systems and examine advanced capabilities and technologies to verify Mars 2024 Forward architecture precursor pathfinder options: Integrated spacecraft/surface infrastructure fluid architecture: propulsion, power, life support center dot Power system feed and propellant scavenging from propulsion system center dot High quality oxygen for life support and EVA Fluid/cryogenic zero-loss transfer and long-term storage center dot Rapid depot-to-rover/spacecraft center dot Slow ISRU plant-to-ascent vehicle Integration of ISRU consumable production center dot Oxygen only from Mars atmosphere carbon dioxide center dot Oxygen, fuel, water, from extraterrestrial soil/regolith Test bed to evaluate long duration life, operations, maintenance on hardware, sensors, and autonomy

  17. Double mimicry evades tRNA synthetase editing by toxic vegetable-sourced non-proteinogenic amino acid.

    PubMed

    Song, Youngzee; Zhou, Huihao; Vo, My-Nuong; Shi, Yi; Nawaz, Mir Hussain; Vargas-Rodriguez, Oscar; Diedrich, Jolene K; Yates, John R; Kishi, Shuji; Musier-Forsyth, Karin; Schimmel, Paul

    2017-12-22

    Hundreds of non-proteinogenic (np) amino acids (AA) are found in plants and can in principle enter human protein synthesis through foods. While aminoacyl-tRNA synthetase (AARS) editing potentially provides a mechanism to reject np AAs, some have pathological associations. Co-crystal structures show that vegetable-sourced azetidine-2-carboxylic acid (Aze), a dual mimic of proline and alanine, is activated by both human prolyl- and alanyl-tRNA synthetases. However, it inserts into proteins as proline, with toxic consequences in vivo. Thus, dual mimicry increases odds for mistranslation through evasion of one but not both tRNA synthetase editing systems.

  18. Influence of Reinforcement Parameters and Ageing Time on Mechanical Behavior of Novel Al2024/SiC/Red Mud Composites Using Response Surface Methodology

    NASA Astrophysics Data System (ADS)

    Singh, Jaswinder; Chauhan, Amit

    2017-12-01

    This study investigates the mechanical behavior of aluminum 2024 matrix composites reinforced with silicon carbide and red mud particles. The hybrid reinforcements were successfully incorporated into the alloy matrix using the stir casting process. An orthogonal array based on Taguchi's technique was used to acquire experimental data for mechanical properties (hardness and impact energy) of the composites. The analysis of variance (ANOVA) and response surface methodology (RSM) techniques were used to evaluate the influence of test parameters (reinforcement ratio, particle size and ageing time). The morphological analysis of the surfaces (fractured during impact tests) was conducted to identify the failure mechanism. Finally, a confirmation experiment was performed to check the adequacy of the developed model. The results indicate that the ageing time is the most effective parameter as far as the hardness of the hybrid composites is concerned. It has also been revealed that red mud wt.% has maximum influence on the impact energy characteristics of the hybrid composites. The study concludes that Al2024/SiC/red mud hybrid composites possess superior mechanical performance in comparison to pure alloy under optimized conditions.

  19. An Existential Approach: An Alternative to the AA Model of Recovery

    ERIC Educational Resources Information Center

    Rogers, Maria A.; Cobia, Debra

    2008-01-01

    Alcoholics Anonymous (AA) is the most widely used organization for the treatment of alcoholism. AA's philosophy has changed how many people view themselves and their substance use. The majority of substance abuse programs in the United States use the 12 steps, either by making them the basis of their treatment program, or by introducing AA to…

  20. Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease

    PubMed Central

    Zhang, Beiru; Une, Yumi; Fu, Xiaoying; Yan, Jingmin; Ge, FengXia; Yao, Junjie; Sawashita, Jinko; Mori, Masayuki; Tomozawa, Hiroshi; Kametani, Fuyuki; Higuchi, Keiichi

    2008-01-01

    AA amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction, but little is known about the underlying mechanisms. Given the transmissible characteristics of AA amyloidosis, transmission between captive cheetahs may be a possible mechanism involved in the high incidence of AA amyloidosis. In this study of animals with AA amyloidosis, we found that cheetah feces contained AA amyloid fibrils that were different from those of the liver with regard to molecular weight and shape and had greater transmissibility. The infectious activity of fecal AA amyloid fibrils was reduced or abolished by the protein denaturants 6 M guanidine·HCl and formic acid or by AA immunodepletion. Thus, we propose that feces are a vehicle of transmission that may accelerate AA amyloidosis in captive cheetah populations. These results provide a pathogenesis for AA amyloidosis and suggest possible measures for rescuing cheetahs from extinction. PMID:18474855

  1. Evaluation of Effect CAT -262C/T, SOD + 35A/C, GPx1 Pro197Leu Polymorphisms in Patients with IBD in the Polish Population.

    PubMed

    Mrowicki, Jerzy; Mrowicka, Małgorzata; Majsterek, Ireneusz; Mik, Michał; Dziki, Adam; Dziki, Łukasz

    2016-12-01

    Inflammatory bowel disease (IBD) are a heterogeneous group of disorders in the course dominated by chronic, recurrent gastrointestinal inflammation. It is believed that the activation of IBD occurs in patients with a genetic predisposition to their development. Chronic inflammation develops as a result of an excessive reaction of the immune system principally under the influence of environmental risk factors. Among them, it has been shown that the mechanism of oxidative stress is associated with the pathophysiology of inflammatory bowel disease, responsible for the commencement and progress of these diseases. The aim of the study was the relationship between single nucleotide polymorphisms (SNPs) of individual antioxidant enzymes, and the prevalence of inflammatory bowel disease that may be associated with increased levels of oxidative stress. A total of 111 IBD patients, including 65 patients with ulcerative colitis (UC) and 46 with Crohn's disease (CD) and 125 healthy controls recruited from the Polish population, were genotyped for CAT -262C / T (rs1001179), SOD + 35A / C (rs2234694), GPx Pro 197 Leu polymorphisms. Genotyping of CAT, SOD, GPx gene polymorphism was performed by a RFLP-PCR. The performed analysis of genetic polymorphisms of antioxidant enzymes showed that polymorphic variant of the CAT -262 C / T may have protective effects in patients with ulcerative colitis in the range of genotype C / T; OR = 0.49 (0.25-0.99), p = 0.044. Trend protective, but statistically unrelated, it was also observed for genotype T / T and T allele of the same polymorphism and genotypes and alleles + 35A / C SOD1 in UC as well as polymorphic variants CAT -262 C / T, Pro197Leu of GPx1, + 35A / C SOD1 in CD. The results were compared with a control group of potentially healthy individuals without such diseases. It has been shown that the polymorphism of antioxidant enzymes CAT gene -262 C / T may have protective effects in patients who are carriers of a genotype C / T at the

  2. Core-halo age gradients and star formation in the Orion Nebula and NGS 2024 young stellar clusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Getman, Konstantin V.; Feigelson, Eric D.; Kuhn, Michael A.

    2014-06-01

    We analyze age distributions of two nearby rich stellar clusters, the NGC 2024 (Flame Nebula) and Orion Nebula cluster (ONC) in the Orion molecular cloud complex. Our analysis is based on samples from the MYStIX survey and a new estimator of pre-main sequence (PMS) stellar ages, Age{sub JX} , derived from X-ray and near-infrared photometric data. To overcome the problem of uncertain individual ages and large spreads of age distributions for entire clusters, we compute median ages and their confidence intervals of stellar samples within annular subregions of the clusters. We find core-halo age gradients in both the NGC 2024more » cluster and ONC: PMS stars in cluster cores appear younger and thus were formed later than PMS stars in cluster peripheries. These findings are further supported by the spatial gradients in the disk fraction and K-band excess frequency. Our age analysis is based on Age{sub JX} estimates for PMS stars and is independent of any consideration of OB stars. The result has important implications for the formation of young stellar clusters. One basic implication is that clusters form slowly and the apparent age spreads in young stellar clusters, which are often controversial, are (at least in part) real. The result further implies that simple models where clusters form inside-out are incorrect and more complex models are needed. We provide several star formation scenarios that alone or in combination may lead to the observed core-halo age gradients.« less

  3. WATER AND METHANOL MASER ACTIVITIES IN THE NGC 2024 FIR 6 REGION

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Choi, Minho; Kang, Miju; Byun, Do-Young

    The NGC 2024 FIR 6 region was observed in the water maser line at 22 GHz and the methanol class I maser lines at 44, 95, and 133 GHz. The water maser spectra displayed several velocity components and month-scale time variabilities. Most of the velocity components may be associated with FIR 6n, while one component was associated with FIR 4. A typical lifetime of the water maser velocity components is about eight months. The components showed velocity fluctuations with a typical drift rate of about 0.01 km s{sup -1} day{sup -1}. The methanol class I masers were detected toward FIRmore » 6. The methanol emission is confined within a narrow range around the systemic velocity of the FIR 6 cloud core. The methanol masers suggest the existence of shocks driven by either the expanding H II region of FIR 6c or the outflow of FIR 6n.« less

  4. Hepatic extraction and renal production of 3,3'-diiodothyronine and 3',5'-diiodothyronine in man.

    PubMed Central

    Faber, J; Faber, O K; Lund, B; Kirkegaard, C; Wahren, J

    1980-01-01

    The sequential deiodination of thyroxine (T4) gives rise to several iodothyronine analogs including 3,3'-diiodothyronine (3,3'-T2) and 3',5'-diiodothyronine (3',5'-T2). In vitro animal studies suggest that the liver and the kidneys are the main sites of both formation and degradation of 3,3'-T2 and 3',5'-T2. To determine the metabolism of 3,3'-T2 and 3',5'-T2 in human liver and kidneys plasma samples were obtained from (a) a brachial artery and a hepatic vein in 20 normal subjects, and from (b) a femoral artery and a renal vein in 11 normal subjects. Further, the hepatic plasma flow (a) and the renal plasma flow (b) were determined. Both plasma 3,3'-T2 and 3',5'-T2 levels were reduced in the hepatic venous blood as compared to arterial values (1.09 +/- 0.40 vs. 1.75 +/- 0.74 ng/dl (P < 0.02)) (mean +/- 1 SD). This resulted in a hepatic extraction of both, 3,3'-T2 and 3',5'-T2, which averaged 8.2 and 5.2 microgram/d, respectively. Plasma 3,3'-T2 as well as 3'5'-T2 levels were higher in the renal vein as compared to arterial values, 1.49 +/- 0.42 vs. 1.39 +/- 0.45 ng/dl (P < 0.05) and 2.35 +/- 0.83 vs. 2.09 +/- 0.81 ng/dl (P < 0.05), respectively. This positive venoarterial difference implies a net production of 3,3'-T2 and 3',5'-T2 in the kidneys of 1.2 and 3.0 microgram/d, respectively. It is concluded that the liver is an important site of 3,3'-T2 and 3',5'-T2 extraction in normal man. In contrast, the renal production of 3,3'-T2 as well as 3'5'-T2 exceeds the degradation and urinary excretion. PMID:6776146

  5. Through-thickness recrystallization characteristics of a laminated AA3xxx–AA6xxx aluminum alloy system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liao, L.H., E-mail: l2liao@uwaterloo.ca; Jin, H.; Gallerneault, M.

    2015-03-15

    The through-thickness annealing behavior of a laminated AA3xxx–AA6xxx alloy system at 300 °C has been studied by scanning electron microscopy, electron backscatter diffraction analysis, electron probe micro-analysis, differential scanning calorimetry, and hardness measurement. Results show that the recrystallization process starts at the interface region between the AA3xxx (clad) and AA6xxx (core) layers. Subsequently, the recrystallization process front progresses into the core layer, while the clad layer is the last region to recrystallize. It is also found that precipitation precedes recrystallization in the entire laminate at the investigated temperature. The preferential onset of recrystallization at the interface region is attributed tomore » the net driving pressure being the highest in this region. The factors that lead to such enhanced net driving pressure are (a) deformation incompatibility between the two alloy layers, (b) lower solute content of the interface, which also leads to lower volume fraction of precipitates, and (c) an accelerated rate of precipitate coarsening due to the presence of a higher density of dislocations. The gradual progress of recrystallization from the interface towards the core layer is dictated by precipitate coarsening and the dependence of its rate on the density of deformation-induced dislocations. The lower driving pressure due to lower work hardening capacity, high solute drag pressure due to Mn, and additional Zener drag from precipitates that form due to solute redistribution during annealing explain the late initiation of recrystallization in the clad layer. - Highlights: • The through-thickness recrystallization of a laminated system is investigated. • The early onset of recrystallization at the interface is discussed. • The effects of precipitation and coarsening on recrystallization are analyzed.« less

  6. Characterization of spatial distortion in a 0.35 T MRI-guided radiotherapy system

    NASA Astrophysics Data System (ADS)

    Ginn, John S.; Agazaryan, Nzhde; Cao, Minsong; Baharom, Umar; Low, Daniel A.; Yang, Yingli; Gao, Yu; Hu, Peng; Lee, Percy; Lamb, James M.

    2017-06-01

    Spatial distortion results in image deformation that can degrade accurate targeting and dose calculations in MRI-guided adaptive radiotherapy. The authors present a comprehensive assessment of a 0.35 T MRI-guided radiotherapy system’s spatial distortion using two commercially-available phantoms with regularly spaced markers. Images of the spatial integrity phantoms were acquired using five clinical protocols on the MRI-guided radiotherapy machine with the radiotherapy gantry positioned at various angles. Software was developed to identify and localize all phantom markers using a template matching approach. Rotational and translational corrections were implemented to account for imperfect phantom alignment. Measurements were made to assess uncertainties arising from susceptibility artifacts, image noise, and phantom construction accuracy. For a clinical 3D imaging protocol with a 1.5 mm reconstructed slice thickness, 100% of spheres within a 50 mm radius of isocenter had a 3D deviation of 1 mm or less. Of the spheres within 100 mm of isocenter, 99.9% had a 3D deviation less than 1 mm. 94.8% and 100% of the spheres within 175 mm were found to be within 1 mm and 2 mm of the expected positions in 3D respectively. Maximum 3D distortions within 50 mm, 100 mm and 175 mm of isocenter were 0.76 mm, 1.15 mm and 1.88 mm respectively. Distortions present in images acquired using the real-time imaging sequence were less than 1 mm for 98.1% and 95.0% of the cylinders within 50 mm and 100 mm of isocenter. The corresponding maximum distortion in these regions was 1.10 mm and 1.67 mm. These results may be used to inform appropriate planning target volume (PTV) margins for 0.35 T MRI-guided radiotherapy. Observed levels of spatial distortion should be explicitly considered when using PTV margins of 3 mm or less or in the case of targets displaced from isocenter by more than 50 mm.

  7. Environmental modulation of autoimmune arthritis involves the spontaneous microbial induction of T cell responses to regulatory determinants within heat shock protein 65.

    PubMed

    Moudgil, K D; Kim, E; Yun, O J; Chi, H H; Brahn, E; Sercarz, E E

    2001-03-15

    Both genetic and environmental factors are believed to be involved in the induction of autoimmune diseases. Adjuvant arthritis (AA) is inducible in susceptible rat strains by injection of Mycobacterium tuberculosis, and arthritic rats raise T cell responses to the 65-kDa mycobacterial heat-shock protein (Bhsp65). We observed that Fischer 344 (F344) rats raised in a barrier facility (BF-F344) are susceptible to AA, whereas F344 rats maintained in a conventional facility (CV-F344) show significantly reduced incidence and severity of AA, despite responding well to the arthritogenic determinant within Bhsp65. The acquisition of protection from AA can be circumvented if rats are maintained on neomycin/acidified water. Strikingly, naive unimmunized CV-F344 rats but not BF-F344 rats raised T cell responses to Bhsp65 C-terminal determinants (BCTD) (we have previously shown that BCTD are involved in regulation of acute AA in the Lewis rat); however, T cells of naive CV-F344 and BF-F344 gave a comparable level of proliferative response to a mitogen, but no response at all to an irrelevant Ag. Furthermore, adoptive transfer into naive BF-F344 rats of splenic cells of naive CV-F344 rats (restimulated with BCTD in vitro) before induction of AA resulted in a considerably reduced severity of AA. These results suggest that spontaneous (inadvertent) priming of BCTD-reactive T cells, owing to determinant mimicry between Bhsp65 and its homologues in microbial agents in the conventional environment, is involved in modulating the severity of AA in CV-F344 rats. These results have important implications in broadening understanding of the host-microbe interaction in human autoimmune diseases.

  8. COACTIVATOR ACTIVATOR (CoAA) PREVENTS THE TRANSCRIPTIONAL ACTIVITY OF RUNT DOMAIN TRANSCRIPTION FACTORS

    PubMed Central

    Li, Xiaodong; Hoeppner, Luke H.; Jensen, Eric D.; Gopalakrishnan, Rajaram; Westendorf, Jennifer J.

    2013-01-01

    Runx proteins are essential for a number of developmental processes and are aberrantly expressed in many human cancers. Runx factors bind DNA and co-factors to activate or repress genes crucial for bone formation, hematopoiesis, and neuronal development. Co-activator activator (CoAA) is a nuclear protein that regulates gene expression, RNA splicing and is overexpressed in many human tumors. In this study, we identified CoAA as a Runx2 binding protein. CoAA repressed Runx factor-dependent activation of reporter genes in a histone deacetylase-independent manner. CoAA also blocked Runx2-mediated repression of the Axin2 promoter, a novel Runx target gene. The carboxy-terminus of CoAA is essential for binding the Runt domains of Runx1 and Runx2. In electophoretic mobility shift assays, CoAA inhibited Runx2 interactions with DNA. These data indicate that CoAA is an inhibitor of Runx factors and can negate Runx factor regulation of gene expression. CoAA is expressed at high levels in human fetal osteoblasts and osteosarcoma cell lines. Suppression of CoAA expression by RNA interference reduced osteosarcoma cell viability in vitro, suggesting that it contributes to the proliferation and/or survival of osteoblast lineage cells. PMID:19585539

  9. Interleukin-35 induces regulatory B cells that suppress autoimmune disease.

    PubMed

    Wang, Ren-Xi; Yu, Cheng-Rong; Dambuza, Ivy M; Mahdi, Rashid M; Dolinska, Monika B; Sergeev, Yuri V; Wingfield, Paul T; Kim, Sung-Hye; Egwuagu, Charles E

    2014-06-01

    Interleukin-10 (IL-10)-producing regulatory B (Breg) cells suppress autoimmune disease, and increased numbers of Breg cells prevent host defense to infection and promote tumor growth and metastasis by converting resting CD4(+) T cells to regulatory T (Treg) cells. The mechanisms mediating the induction and development of Breg cells remain unclear. Here we show that IL-35 induces Breg cells and promotes their conversion to a Breg subset that produces IL-35 as well as IL-10. Treatment of mice with IL-35 conferred protection from experimental autoimmune uveitis (EAU), and mice lacking IL-35 (p35 knockout (KO) mice) or defective in IL-35 signaling (IL-12Rβ2 KO mice) produced less Breg cells endogenously or after treatment with IL-35 and developed severe uveitis. Adoptive transfer of Breg cells induced by recombinant IL-35 suppressed EAU when transferred to mice with established disease, inhibiting pathogenic T helper type 17 (TH17) and TH1 cells while promoting Treg cell expansion. In B cells, IL-35 activates STAT1 and STAT3 through the IL-35 receptor comprising the IL-12Rβ2 and IL-27Rα subunits. As IL-35 also induced the conversion of human B cells into Breg cells, these findings suggest that IL-35 may be used to induce autologous Breg and IL-35(+) Breg cells and treat autoimmune and inflammatory disease.

  10. Ribosomal incorporation of backbone modified amino acids via an editing-deficient aminoacyl-tRNA synthetase.

    PubMed

    Iqbal, Emil S; Dods, Kara K; Hartman, Matthew C T

    2018-02-14

    The ability to incorporate non-canonical amino acids (ncAA) using translation offers researchers the ability to extend the functionality of proteins and peptides for many applications including synthetic biology, biophysical and structural studies, and discovery of novel ligands. Here we describe the high promiscuity of an editing-deficient valine-tRNA synthetase (ValRS T222P). Using this enzyme, we demonstrate ribosomal translation of 11 ncAAs including those with novel side chains, α,α-disubstitutions, and cyclic β-amino acids.

  11. AaCAT1 of the Yellow Fever Mosquito, Aedes aegypti

    PubMed Central

    Hansen, Immo A.; Boudko, Dmitri Y.; Shiao, Shin-Hong; Voronov, Dmitri A.; Meleshkevitch, Ella A.; Drake, Lisa L.; Aguirre, Sarah E.; Fox, Jeffrey M.; Attardo, Geoffrey M.; Raikhel, Alexander S.

    2011-01-01

    Insect yolk protein precursor gene expression is regulated by nutritional and endocrine signals. A surge of amino acids in the hemolymph of blood-fed female mosquitoes activates a nutrient signaling system in the fat bodies, which subsequently derepresses yolk protein precursor genes and makes them responsive to activation by steroid hormones. Orphan transporters of the SLC7 family were identified as essential upstream components of the nutrient signaling system in the fat body of fruit flies and the yellow fever mosquito, Aedes aegypti. However, the transport function of these proteins was unknown. We report expression and functional characterization of AaCAT1, cloned from the fat body of A. aegypti. Expression of AaCAT1 transcript and protein undergoes dynamic changes during postembryonic development of the mosquito. Transcript expression was especially high in the third and fourth larval stages; however, the AaCAT1 protein was detected only in pupa and adult stages. Functional expression and analysis of AaCAT1 in Xenopus oocytes revealed that it acts as a sodium-independent cationic amino acid transporter, with unique selectivity to l-histidine at neutral pH (K0.5l-His = 0.34 ± 0.07 mm, pH 7.2). Acidification to pH 6.2 dramatically increases AaCAT1-specific His+-induced current. RNAi-mediated silencing of AaCAT1 reduces egg yield of subsequent ovipositions. Our data show that AaCAT1 has notable differences in its transport mechanism when compared with related mammalian cationic amino acid transporters. It may execute histidine-specific transport and signaling in mosquito tissues. PMID:21262963

  12. Astronauts Koichi Wakata (left) and Daniel T. Barry check the settings on a 35mm camera during an

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-72 TRAINING VIEW --- Astronauts Koichi Wakata (left) and Daniel T. Barry check the settings on a 35mm camera during an STS-72 training session. Wakata is a mission specialist, representing Japan's National Space Development Agency (NASDA) and Barry is a United States astronaut assigned as mission specialist for the same mission. The two are on the aft flight deck of the fixed base Shuttle Mission Simulator (SMS) at the Johnson Space Center (JSC).

  13. Enhanced nematicidal potential of the chitinase pachi from Pseudomonas aeruginosa in association with Cry21Aa

    PubMed Central

    Chen, Lin; Jiang, Huang; Cheng, Qipeng; Chen, Junpeng; Wu, Gaobing; Kumar, Ashok; Sun, Ming; Liu, Ziduo

    2015-01-01

    Nematodes are known to be harmful to various crops, vegetables, plants and insects. The present study reports that, chitin upregulates the activity of chitinase (20%) and nematicidal potential (15%) of Pseudomonas aeruginosa. The chitinase gene (pachi) from P. aeruginosa was cloned, and its nematicidal activity of pachi protein against Caenorhabditis elegans was studied. The mortality rate induced by pachi increased by 6.3-fold when in association with Cry21Aa from Bacillus thuringiensis. Pachi efficiently killed C. elegans in its native state (LC50 = 387.3 ± 31.7 μg/ml), as well as in association with Cry21Aa (LC50 = 30.9 ± 4.1 μg/ml), by degrading the cuticle, egg shell and intestine in a relatively short time period of 24 h. To explore the nematidal potential of chitinase, six fusion proteins were constructed using gene engineering techniques. The CHACry showed higher activity against C. elegans than others owing to its high solubility. Notably, the CHACry showed a synergistic factor of 4.1 versus 3.5 a mixture [1:1] of pachi and Cry21Aa. The present study has identified eco-friendly biological routes (e.g., mixed proteins, fusion proteins) with potent nematicidal activity, which not only can help to prevent major crop losses but also strengthen the agro-economy and increase gross crop yield. PMID:26400097

  14. AA amyloidosis complicating the hereditary periodic fever syndromes.

    PubMed

    Lane, Thirusha; Loeffler, Jutta M; Rowczenio, Dorota M; Gilbertson, Janet A; Bybee, Alison; Russell, Tonia L; Gillmore, Julian D; Wechalekar, Ashutosh D; Hawkins, Philip N; Lachmann, Helen J

    2013-04-01

    AA amyloidosis is a life-threatening complication of the hereditary periodic fever syndromes (HPFS), which are otherwise often compatible with normal life expectancy. This study was undertaken to determine the characteristics, presentation, natural history, and response to treatment in 46 patients who had been referred for evaluation at the UK National Amyloidosis Centre. Disease activity was monitored by serial measurement of serum amyloid A. Renal function was assessed by measurement of serum creatinine and albumin levels, the estimated glomerular filtration rate, and proteinuria from 24-hour urine collections. The amyloid load was measured by serum amyloid P scintigraphy. Twenty-four patients had familial Mediterranean fever, 12 patients had tumor necrosis factor receptor-associated periodic syndrome, 6 patients had cryopyrin-associated periodic syndromes, and 4 patients had mevalonate kinase deficiency. The median age at onset of HPFS was 5 years; median age at presentation with AA amyloidosis was 38 years. Diagnosis of an HPFS had not been considered prior to presentation with AA amyloidosis in 23 patients (50%). Eleven patients (24%) had end-stage renal failure (ESRF) at presentation; of these, 3 had received transplants prior to referral. A further 13 patients developed ESRF over the followup period, with 10 undergoing renal transplantation. The median time to progression to ESRF from onset of AA amyloidosis was 3.3 years (interquartile range [IQR] 2-8), with a median time to transplant of 4 years (IQR 3-6). Eleven patients (24%) died. The median survival in the entire cohort was 19 years from diagnosis of AA amyloidosis. Of the 37 patients who were treated successfully, or in whom at least partial suppression of the underlying HPFS was achieved, 17 (46%) showed amyloid regression, 14 (38%) showed a stable amyloid load, and 2 (5%) showed increased amyloid deposition over the followup period. AA amyloidosis remains a challenging and serious late complication

  15. Donor CTLA-4 genotype influences clinical outcome after T cell-depleted allogeneic hematopoietic stem cell transplantation from HLA-identical sibling donors.

    PubMed

    Bosch-Vizcaya, Anna; Pérez-García, Arianne; Brunet, Salut; Solano, Carlos; Buño, Ismael; Guillem, Vicent; Martínez-Laperche, Carolina; Sanz, Guillermo; Barrenetxea, Cristina; Martínez, Carmen; Tuset, Esperanza; Lloveras, Natàlia; Coll, Rosa; Guardia, Ramon; González, Yolanda; Roncero, Josep M; Bustins, Anna; Gardella, Santiago; Fernández, Cristalina; Buch, Joan; Gallardo, David

    2012-01-01

    CTLA-4 (cytotoxic T-lymphocyte antigen-4) plays a pivotal role in inhibiting T cell activation through competitive interaction with B7 molecules and interruption of costimulatory signals mediated by CD28. Polymorphisms on the CTLA-4 gene have been previously associated with autoimmune diseases, predisposition to leukemic relapse, and with graft-versus-host disease (GVHD) or relapse after allogeneic transplant. As CTLA-4 is expressed on T-lymphocytes, the aim of this study was to determine whether the donor CTLA-4 CT60 genotype also influences clinical outcome even after T cell depletion with CD34-positive selection. We studied 136 patient-donor pairs. Overall survival (OS) was worse for those patients who received grafts from a donor with the CT60 AA genotype rather than from a donor with the AG or GG genotype (35.6% vs 49.4%; P = .043). This association was confirmed through multivariate analysis, which identified the donor CT60 genotype as an independent risk factor for OS (P = .008; hazard ratio [HR]: 2.24, 95% confidence interval [CI]: 1.23-4.08). The donor CT60 AA genotype was also associated with lower disease-free survival, this being related to an increased risk of relapse (P = .001; HR: 3.41, 95% CI: 1.67-6.96) and a trend toward higher transplant-related mortality. These associations were stronger when considering only patients in the early stage of disease. Our results suggest that graft-versus-leukemia (GVL) activity after T cell depletion is conditioned by the donor CTLA-4 genotype. Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

  16. Computational Insights into the High-Fidelity Catalysis of Aminoacyl-tRNA Synthetases

    NASA Astrophysics Data System (ADS)

    Aboelnga, Mohamed M.

    Obtaining insights into the catalytic function of enzymes is an important area of research due to their widespread applications in the biotechnology and pharmaceutical industries. Among these enzymes, the aminoacyl-tRNA synthetases (aaRSs) are known for their remarkable fidelity in catalyzing the aminoacylation reactions of tRNA in protein biosynthesis. Despite the exceptional execution of this critical function, mechanistic details of the reactions catalyzed by aminoacyl-tRNA synthetases remain elusive demonstrating the obvious need to explore their remarkable chemistry. During the PhD studies reported in this thesis the mechanism of aminoacylation, pre?transfer editing and post?transfer editing catalyzed by different aaRS have been established using multi-scale computational enzymology. In the first two chapters a detailed information about aaRS and the addressed questions was given in addition to an overview of the used computational methodology currently used to investigate the enzymatic mechanisms. The aminoacylation mechanism of threonine by Threonyl-tRNA synthetases, glutamine by Glutaminyl-tRNA synthetases and glutamate by Glutamyl-tRNA synthetases have been clearly unveiled in chapter 3 and 4. Also, valuable information regarding the role of cofactors and active site residues has been obtained. While investigating the post-transfer editing mechanisms, which proceed in a remote and distinct active site, two different scenarios were experimentally suggested for two types of threonyl-tRNA synthetase species to correct the misacylation of the structurally related serine. We explored these two mechanisms as in chapters 5 and 6. Moreover, the synthetic site in which the aminoacylation reaction is catalyzed, is also responsible for a second type of proofreading reaction called pre-transfer editing mechanism. In chapter 7, this latter mechanism has been elucidated for both Seryl-tRNA synthetases and Isoleucyl-tRNA synthetases against their non-cognate substrates

  17. Improvement in Fatigue Performance of Aluminium Alloy Welded Joints by Laser Shock Peening in a Dynamic Strain Aging Temperature Regime.

    PubMed

    Su, Chun; Zhou, Jianzhong; Meng, Xiankai; Huang, Shu

    2016-09-26

    As a new treatment process after welding, the process parameters of laser shock peening (LSP) in dynamic strain aging (DSA) temperature regimes can be precisely controlled, and the process is a non-contact one. The effects of LSP at elevated temperatures on the distribution of the surface residual stress of AA6061-T6 welded joints were investigated by using X-ray diffraction technology with the sin² ϕ method and Abaqus software. The fatigue life of the welded joints was estimated by performing tensile fatigue tests. The microstructural evolution in surface and fatigue fractures of the welded joints was presented by means of surface integrity and fracture surface testing. In the DSA temperature regime of AA6061-T6 welded joints, the residual compressive stress was distributed more stably than that of LSP at room temperature. The thermal corrosion resistance and fatigue properties of the welded joints were also improved. The experimental results and numerical analysis were in mutual agreement.

  18. Improvement in Fatigue Performance of Aluminium Alloy Welded Joints by Laser Shock Peening in a Dynamic Strain Aging Temperature Regime

    PubMed Central

    Su, Chun; Zhou, Jianzhong; Meng, Xiankai; Huang, Shu

    2016-01-01

    As a new treatment process after welding, the process parameters of laser shock peening (LSP) in dynamic strain aging (DSA) temperature regimes can be precisely controlled, and the process is a non-contact one. The effects of LSP at elevated temperatures on the distribution of the surface residual stress of AA6061-T6 welded joints were investigated by using X-ray diffraction technology with the sin2ϕ method and Abaqus software. The fatigue life of the welded joints was estimated by performing tensile fatigue tests. The microstructural evolution in surface and fatigue fractures of the welded joints was presented by means of surface integrity and fracture surface testing. In the DSA temperature regime of AA6061-T6 welded joints, the residual compressive stress was distributed more stably than that of LSP at room temperature. The thermal corrosion resistance and fatigue properties of the welded joints were also improved. The experimental results and numerical analysis were in mutual agreement. PMID:28773920

  19. Minutes of the Conference on the International Committee on Aeronautical Fatigue (10th) Held in Melbourne, Australia on May 1967

    DTIC Science & Technology

    1968-02-01

    Effects A room temperature, axial-loading low-cycle fatigue investigation on 2024 -T4 and 7075--T6 aluminum alloys ...Hudson, C. Michael: Investigation of the Effect of Stress Ratio on Fatigue Crack Growth in 7075-T6 Aluminum Alloy . To be presented at Symposium on...Stress Ratio on Fatigue Crack Growth and Mode of Fracture in 2024 -T4 and 7075-T6 Aluminum Alloys in the Low-Cycle Range. Air Force Materials Laboratory

  20. Through-process modelling of texture and anisotropy in AA5182

    NASA Astrophysics Data System (ADS)

    Crumbach, M.; Neumann, L.; Goerdeler, M.; Aretz, H.; Gottstein, G.; Kopp, R.

    2006-07-01

    A through-process texture and anisotropy prediction for AA5182 sheet production from hot rolling through cold rolling and annealing is reported. Thermo-mechanical process data predicted by the finite element method (FEM) package T-Pack based on the software LARSTRAN were fed into a combination of physics based microstructure models for deformation texture (GIA), work hardening (3IVM), nucleation texture (ReNuc), and recrystallization texture (StaRT). The final simulated sheet texture was fed into a FEM simulation of cup drawing employing a new concept of interactively updated texture based yield locus predictions. The modelling results of texture development and anisotropy were compared to experimental data. The applicability to other alloys and processes is discussed.