Modulation of Plasma Membrane Ca2+-ATPase by Neutral Phospholipids

PubMed Central

Pignataro, María Florencia; Dodes-Traian, Martín M.; González-Flecha, F. Luis; Sica, Mauricio; Mangialavori, Irene C.; Rossi, Juan Pablo F. C.

2015-01-01

The effects of lipids on membrane proteins are likely to be complex and unique for each membrane protein. Here we studied different detergent/phosphatidylcholine reconstitution media and tested their effects on plasma membrane Ca2+ pump (PMCA). We found that Ca2+-ATPase activity shows a biphasic behavior with respect to the detergent/phosphatidylcholine ratio. Moreover, the maximal Ca2+-ATPase activity largely depends on the length and the unsaturation degree of the hydrocarbon chain. Using static light scattering and fluorescence correlation spectroscopy, we monitored the changes in hydrodynamic radius of detergent/phosphatidylcholine particles during the micelle-vesicle transition. We found that, when PMCA is reconstituted in mixed micelles, neutral phospholipids increase the enzyme turnover. The biophysical changes associated with the transition from mixed micelles to bicelles increase the time of residence of the phosphorylated intermediate (EP), decreasing the enzyme turnover. Molecular dynamics simulations analysis of the interactions between PMCA and the phospholipid bilayer in which it is embedded show that in the 1,2-dioleoyl-sn-glycero-3-phosphocholine bilayer, charged residues of the protein are trapped in the hydrophobic core. Conversely, in the 1,2-dimyristoyl-sn-glycero-3-phosphocholine bilayer, the overall hydrophobic-hydrophilic requirements of the protein surface are fulfilled the best, reducing the thermodynamic cost of exposing charged residues to the hydrophobic core. The apparent mismatch produced by a 1,2-dioleoyl-sn-glycero-3-phosphocholine thicker bilayer could be a structural foundation to explain its functional effect on PMCA. PMID:25605721

Validation of a serum neutralization test for detection of antibodies specific to cyprinid herpesvirus 3 in infected common and koi carp (Cyprinus carpio).

PubMed

Cabon, J; Louboutin, L; Castric, J; Bergmann, S; Bovo, G; Matras, M; Haenen, O; Olesen, N J; Morin, T

2017-05-01

Cyprinid herpesvirus 3 (CyHV-3) is the aetiological agent of a serious infective, notifiable disease affecting common carp and varieties. In survivors, infection is generally characterized by a subclinical latency phase with restricted viral replication. The CyHV-3 genome is difficult to detect in such carrier fish that represent a potential source of dissemination if viral reactivation occurs. In this study, the analytical and diagnostic performance of an alternative serum neutralization (SN) method based on the detection of CyHV-3-specific antibodies was assessed using 151 serum or plasma samples from healthy and naturally or experimentally CyHV-3-infected carp. French CyHV-3 isolate 07/108b was neutralized efficiently by sera from carp infected with European, American and Taiwanese CyHV-3 isolates, but no neutralization was observed using sera specific to other aquatic herpesviruses. Diagnostic sensitivity, diagnostic specificity and repeatability of 95.9%, 99.0% and 99.3%, respectively, were obtained, as well as a compliance rate of 89.9% in reproducibility testing. Neutralizing antibodies were steadily detected in infected carp subjected to restrictive or permissive temperature variations over more than 25 months post-infection. The results suggest that this non-lethal diagnostic test could be used in the future to improve the epidemiological surveillance and control of CyHV-3 disease. © 2016 John Wiley & Sons Ltd.

Evidence that Surface Proteins Sn14 and Sn16 of Sarcocystis neurona Merozoites Are Involved in Infection and Immunity†

PubMed Central

Liang, Fang Ting; Granstrom, David E.; Zhao, Xiao Min; Timoney, John F.

1998-01-01

Sarcocystis neurona is the etiologic agent of equine protozoal myeloencephalitis (EPM). Based on an analysis of 25,000 equine serum and cerebrospinal fluid (CSF) samples, including samples from horses with neurologic signs typical of EPM or with histologically or parasitologically confirmed EPM, four major immunoblot band patterns have been identified. Twenty-three serum and CSF samples representing each of the four immunoblot patterns were selected from 220 samples from horses with neurologic signs resembling EPM and examined for inhibitory effects on the infectivity of S. neurona by an in vitro neutralization assay. A high correlation between immunoblot band pattern and neutralizing activity was detected. Two proteins, Sn14 and Sn16 (14 and 16 kDa, respectively), appeared to be important for in vitro infection. A combination of the results of surface protein labeling, immunoprecipitation, Western blotting, and trypsin digestion suggests that these molecules are surface proteins and may be useful components of a vaccine against S. neurona infection. Although S. neurona is an obligate intracellular parasite, it is potentially a target for specific antibodies which may lyse merozoites via complement or inhibit their attachment and penetration to host cells. PMID:9573058

New μ-SnTe{sub 4} and μ-Sn{sub 2}Te{sub 6} ligands to transition metal: Solvothermal syntheses and characterizations of zinc tellurostannates containing polyamine ligands

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

Lu, Jialin; Wang, Fang; Shen, Yali

2014-08-15

Zinc tellurostannates [(Zn(teta)){sub 2}(μ-1κ:2κ-SnTe{sub 4})] (1), [(Zn(teta)){sub 3}(μ{sub 3}-1κ:2κ:3κ-SnTe{sub 4})]I{sub 2} (2), [(Zn(tren)){sub 2}(μ-1κ:2κ-Sn{sub 2}Te{sub 6})] (3), and [Zn(dien){sub 2}]{sub 4}(Sn{sub 2}Te{sub 6}){sub 1.75}(Sn{sub 2}Te{sub 8}){sub 0.25}·dien (4) were prepared by the reactions of Zn, Sn, and Te with iodine ion assistant in teta and dien. The tetrahedral [SnTe{sub 4}]{sup 4−} anion coordinates to two [Zn(teta)]{sup 2+} units as a bidentate μ-1κ:2κ-SnTe{sub 4} ligand to form the neutral complex 1. It coordinates to three [Zn(teta)]{sup 2+} units with a tridentate μ{sub 3}-1κ:2κ:3κ coordination modes, generating a complex cation [(Zn(teta)){sub 3}(μ{sub 3}-1κ:2κ:3κ- SnTe{sub 4})]{sup 2+} in 2. In 3, the [Sn{submore » 2}Te{sub 6}]{sup 4−} anion joins two [Zn(tren)]{sup 2+}cations with the trans terminal Te atoms, forming neutral complex 3. The μ-1κ:2κ-SnTe{sub 4}, μ{sub 3}-1κ:2κ:3κ-SnTe{sub 4}, and μ-1κ:2κ-Sn{sub 2}Te{sub 6} ligands to TM centers in 1–3 have not been observed before. Compound 4 contains a normal [Sn{sub 2}Te{sub 6}]{sup 4−} and an abnormal [(Sn{sub 2}Te{sub 6}){sub 0.75}(Sn{sub 2}Te{sub 8}){sub 0.25}]{sup 4−} anions. Compounds 1–4 exhibit narrow band gaps in the range of 1.47–1.98 eV, and a distinct red-shift of the band gaps is observed from 4 to 1−3. - Graphical abstract: Zinc tellurostannates were prepared with iodine ion assistant in polyamines, and first μ-1κ:2κ-SnTe{sub 4}, μ{sub 3}-1κ:2κ:3κ-SnTe{sub 4}, and μ-1κ:2κ-Sn{sub 2}Te{sub 6} ligands TM centers were obtained. - Highlights: • Zinc-tellurostannates were first prepared with iodine ion assistant. • Novel μ-1κ:2κ-SnTe{sub 4}, μ{sub 3}-1κ:2κ:3κ-SnTe{sub 4}, and μ-1κ:2κ-Sn{sub 2}Te{sub 6} ligands were obtained. • The Zinc tellurostannates exhibit optical bandgaps between 1.47 and 1.98 eV.« less

Study of the interaction mechanisms between absorbed NO{sub 2} and por-Si/SnO{sub x} nanocomposite layers

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

Bolotov, V. V.; Kan, V. E., E-mail: kan@obisp.oscsbras.ru; Makushenko, R. K.

2013-10-15

The interaction mechanisms between NO{sub 2} molecules and the surface of por-Si/SnO{sub x} nanocomposites obtained by magnetron deposition and chemical vapor deposition (CVD) are studied by infrared absorption spectroscopy and electron paramagnetic resonance methods. The observed increase in the free carrier concentration in the por-Si/SnO{sub x} nanocomposite layers is explained by a change in the charge state of P{sub b} centers due to the formation of neutral 'surface defect-adsorbed NO{sub 2} molecule' complexes with free carrier generation in the crystallite bulk. In the nanocomposite layers grown by the CVD method, the increase in the free hole concentration during NO{sub 2}more » adsorption is much less pronounced in comparison with the composite grown by magnetron deposition, which is caused by the competing interaction channel of NO{sub 2} molecules with electrically neutral P{sub b} centers.« less

Neutral Hydrogen Radio Propperties of ASAS-SN Supernovae Hosts

NASA Astrophysics Data System (ADS)

Ross, Timothy W.; Salter, Chris; Ghosh, Tapasi; Minchin, Robert; Jones, Kristen; All-Sky Automated Survey for Supernovae (ASAS-SN)

2018-01-01

We compiled properties of the galaxies containing recent supernovae. The galaxies were observed in the Hydrogen 21-cm region using the Arecibo 305-m Radio Telescope, and the supernovae were found by the All-Sky Automated Survey for Supernovae (ASAS-SN) project. We were able to detect the neutral hydrogen hyperfine transition in 50 new galaxies to date, and retrieved information on 52 host galaxies with previous detections. Including archival detections, the detection rates of Type CC SNe was 96.9%, that of Type Ia was 76.3%, while no Tidal Disruption Events (TDEs) had detections. In all we calculated the integrated HI flux of 102 host galaxies in the Arecibo sky. With the integrated HI flux we calculated mass values. The median HI mass, log [MHI/(h‑2C M⊙)], with h =.73, for all SN host galaxies was 9.47±0.02, with the median for Type Ia hosts being 9.55±0.02 and the median for Type CC being 9.30±0.02.

High-Q plasmas in the TFTR tokamak

NASA Astrophysics Data System (ADS)

Jassby, D. L.; Barnes, C. W.; Bell, M. G.; Bitter, M.; Boivin, R.; Bretz, N. L.; Budny, R. V.; Bush, C. E.; Dylla, H. F.; Efthimion, P. C.; Fredrickson, E. D.; Hawryluk, R. J.; Hill, K. W.; Hosea, J.; Hsuan, H.; Janos, A. C.; Jobes, F. C.; Johnson, D. W.; Johnson, L. C.; Kamperschroer, J.; Kieras-Phillips, C.; Kilpatrick, S. J.; LaMarche, P. H.; LeBlanc, B.; Mansfield, D. K.; Marmar, E. S.; McCune, D. C.; McGuire, K. M.; Meade, D. M.; Medley, S. S.; Mikkelsen, D. R.; Mueller, D.; Owens, D. K.; Park, H. K.; Paul, S. F.; Pitcher, S.; Ramsey, A. T.; Redi, M. H.; Sabbagh, S. A.; Scott, S. D.; Snipes, J.; Stevens, J.; Strachan, J. D.; Stratton, B. C.; Synakowski, E. J.; Taylor, G.; Terry, J. L.; Timberlake, J. R.; Towner, H. H.; Ulrickson, M.; von Goeler, S.; Wieland, R. M.; Williams, M.; Wilson, J. R.; Wong, K.-L.; Young, K. M.; Zarnstorff, M. C.; Zweben, S. J.

1991-08-01

In the Tokamak Fusion Test Reactor (TFTR) [Plasma Phys. Controlled Fusion 26, 11 (1984)], the highest neutron source strength Sn and D-D fusion power gain QDD are realized in the neutral-beam-fueled and heated ``supershot'' regime that occurs after extensive wall conditioning to minimize recycling. For the best supershots, Sn increases approximately as P1.8b. The highest-Q shots are characterized by high Te (up to 12 keV), Ti (up to 34 keV), and stored energy (up to 4.7 MJ), highly peaked density profiles, broad Te profiles, and lower Zeff. Replacement of critical areas of the graphite limiter tiles with carbon-fiber composite tiles and improved alignment with the plasma have mitigated the ``carbon bloom.'' Wall conditioning by lithium pellet injection prior to the beam pulse reduces carbon influx and particle recycling. Empirically, QDD increases with decreasing pre-injection carbon radiation, and increases strongly with density peakedness [ne(0)/] during the beam pulse. To date, the best fusion results are Sn=5×1016 n/sec, QDD=1.85×10-3, and neutron yield=4.0×1016 n/pulse, obtained at Ip=1.6-1.9 MA and beam energy Eb=95-103 keV, with nearly balanced co- and counter-injected beam power. Computer simulations of supershot plasmas show that typically 50%-60% of Sn arises from beam-target reactions, with the remainder divided between beam-beam and thermonuclear reactions, the thermonuclear fraction increasing with Pb. The simulations predict that QDT=0.3-0.4 would be obtained for the best present plasma conditions, if half the deuterium neutral beams were to be replaced by tritium beams. Somewhat higher values are calculated if D beams are injected into a predominantly tritium target plasma. The projected central beta of fusion alphas is 0.4%-0.6%, a level sufficient for the study of alpha-induced collective effects.

Luminescence of defects in the structural transformation of layered tin dichalcogenides

NASA Astrophysics Data System (ADS)

Sutter, P.; Komsa, H.-P.; Krasheninnikov, A. V.; Huang, Y.; Sutter, E.

2017-12-01

Layered tin sulfide semiconductors are both of fundamental interest and attractive for energy conversion applications. Sn sulfides crystallize in several stable bulk phases with different Sn:S ratios (SnS2, Sn2S3, and SnS), which can transform into phases with a lower sulfur concentration by introduction of sulfur vacancies (VS). How this complex behavior affects the optoelectronic properties remains largely unknown but is of key importance for understanding light-matter interactions in this family of layered materials. Here, we use the capability to induce VS and drive a transformation between few-layer SnS2 and SnS by electron beam irradiation, combined with in-situ cathodoluminescence spectroscopy and ab-initio calculations to probe the role of defects in the luminescence of these materials. In addition to the characteristic band-edge emission of the endpoint structures, our results show emerging luminescence features accompanying the SnS2 to SnS transformation. Comparison with calculations indicates that the most prominent emission in SnS2 with sulfur vacancies is not due to luminescence from a defect level but involves recombination of excitons bound to neutral VS in SnS2. These findings provide insight into the intrinsic and defect-related optoelectronic properties of Sn chalcogenide semiconductors.

Charge states and lattice sites of dilute implanted Sn in ZnO

NASA Astrophysics Data System (ADS)

Mølholt, T. E.; Gunnlaugsson, H. P.; Johnston, K.; Mantovan, R.; Röder, J.; Adoons, V.; Mokhles Gerami, A.; Masenda, H.; Matveyev, Y. A.; Ncube, M.; Unzueta, I.; Bharuth-Ram, K.; Gislason, H. P.; Krastev, P.; Langouche, G.; Naidoo, D.; Ólafsson, S.; Zenkevich, A.; ISOLDE Collaboration

2017-04-01

The common charge states of Sn are 2+  and 4+. While charge neutrality considerations favour 2+  to be the natural charge state of Sn in ZnO, there are several reports suggesting the 4+  state instead. In order to investigate the charge states, lattice sites, and the effect of the ion implantation process of dilute Sn atoms in ZnO, we have performed 119Sn emission Mössbauer spectroscopy on ZnO single crystal samples following ion implantation of radioactive 119In (T ½  =  2.4 min) at temperatures between 96 K and 762 K. Complementary perturbed angular correlation measurements on 111mCd implanted ZnO were also conducted. Our results show that the 2+  state is the natural charge state for Sn in defect free ZnO and that the 4+  charge state is stabilized by acceptor defects created in the implantation process.

Neutral gas and diffuse interstellar bands in the LMC

NASA Technical Reports Server (NTRS)

Danks, Anthony C.; Penprase, Brian

1994-01-01

Tracing the dynamics of the neutral gas and observing diffuse interstellar bands in the LMC (Large Magellanic Cloud) was the focus of this study. The S/N values, a Quartz lamp exposure, a T horium Argon Comparision lamp exposure, and spectral plots for each star observed were taken. The stars observed were selected to sample the 30 Dor vicinty. NaI absorption profiles are included.

The immunizing effect and reactogenicity of two live attenuated mumps virus vaccines in Swedish schoolchildren.

PubMed

Christenson, B; Heller, L; Böttiger, M

1983-10-01

An evaluation of the seroconversion and booster effects after vaccination with two different mumps vaccines, the Urabe Am 9 strain and the Jeryl Lynn strain, was carried out in schoolchildren. Four hundred and fifty-four schoolchildren aged 11 to 12 years with no previous history of mumps or mumps vaccination were enrolled for the study. The antibody responses were measured by serum neutralization (SN) and haemolysis-in-gel (HIG) tests. Of the 454 subjects, 130 were found to be initially seronegative. Two lots of different strengths of each vaccine were used to evaluate the relationships. The Urabe Am 9 vaccine lots had infectivity titres of 100 000 and 19 000 TCID50 per dose and the Jeryl Lynn vaccine titres of 59 000 and 28 000 TCID50 per dose. Only slight differences in seroconversion rates were seen between the lots. The overall seroconversion rate, measured by SN, was 94% for the Urabe Am 9 vaccine and 91% for the Jeryl Lynn vaccine, whereas the geometric mean titre for virus-neutralizing antibody in seroconverting children was 7.4 with the Urabe Am 9 vaccine and 10.7 with the Jeryl Lynn vaccine. In children who were seropositive prior to vaccination, a marked rise in antibody titre was found 8 weeks after vaccine injection indicating a booster effect. The miscellaneous post-vaccination side-effects were mild and inconsequential.

LiGe(SiMe₃)₃: A New Substituent for the Synthesis of Metalloid Tin Clusters from Metastable Sn(I) Halide Solutions.

PubMed

Binder, Mareike; Schrenk, Claudio; Block, Theresa; Pöttgen, Rainer; Schnepf, Andreas

2018-04-26

The most fruitful synthetic route to metalloid tin clusters applies the disproportionation reaction of metastable Sn(I) halide solutions, whereby Si(SiMe₃)₃ is mostly used as the stabilizing substituent. Here, we describe the synthesis and application of the slightly modified substituent Ge(SiMe₃)₃, which can be used for the synthesis of metalloid tin clusters to give the neutral cluster Sn 10 [Ge(SiMe₃)₃]₆ as well as the charged clusters {Sn 10 [Ge(SiMe₃)₃]₅} − and {Sn 10 [Ge(SiMe₃)₃]₄} 2− . The obtained metalloid clusters are structurally similar to their Si(SiMe₃)₃ derivatives. However, differences with respect to the stability in solution are observed. Additionally, a different electronic situation for the tin atoms is realized as shown by 119m Sn Mössbauer spectroscopy, giving further insight into the different kinds of tin atoms within the metalloid cluster {Sn 10 [Ge(SiMe₃)₃]₄} 2− . The synthesis of diverse derivatives gives the opportunity to check the influence of the substituent for further investigations of metalloid tin cluster compounds.

An Asymmetric Hypernova (SN 2003jd) Viewed Off-Axis, and a Link to Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Maeda, K.; et al.

2006-02-01

Authors: Keiichi Maeda, Ken Nomoto, Nozomu Tominaga (Tokyo), Paolo Mazzali, Elena Pian (Trieste), Jinsong Deng (Beijing) Type Ic supernovae, the explosions following the core collapse ofmassive stars that have previously lost their hydrogen and heliumenvelopes, are particularly interesting because of the link withlong-duration gamma-ray bursts. Although indications exist that theseexplosions are aspherical, direct evidence has still been missing.Late-time observations of SN 2003jd, a luminous hypernova, providesuch evidence. Recent Subaru and Keck spectra reveal double-peakedprofiles in the nebular lines of neutral oxygen and magnesium. Theseprofiles are different from those of known Type Ic supernovae, with orwithout a gamma-ray burst, and they can be understood if SN 2003jd wasan aspherical, axisymmetric explosion viewed from near the equatorialplane. If SN 2003jd was associated with a gamma-ray burst, we missedthe burst as it was pointing away from us.

Tuneable reactivity with PPh3 and SnX2 of four- and five-coordinate Pd(II) and Pt(II) complexes containing polyphosphines.

PubMed

Fernández-Anca, Damián; García-Seijo, M Inés; García-Fernández, M Esther

2013-07-28

The reactivity of the unusual d(8) trigonal-bipyramidal systems [MX(PP3)]X (X = Cl: M = Pd(1a), Pt(2a); X = Br: M = Pd(3a), Pt(4a); X = I: M = Pd(5a), Pt(6a); PP3 = tris[2-(diphenylphosphino)ethyl]phosphine) in CHCl3-CH3OH, the square-pyramidal compounds [MCl(NP3)]Cl (M = Pd(7a); Pt(8a); NP3 = tris[2-(diphenylphosphino)ethyl]amine) in CD3OD-DMF and the distorted square-planar mononuclear [MX(PNP)]X (M = Pd: X = Cl(10a); M = Pt: X = I(10b); PNP = bis[2-(diphenylphosphino)ethyl]amine) and the heteronuclear [PdAu2X4(PP3)] [X = I(9a), Cl(14a), Br(15a)] and [MAuX2(PP3)]X [M = Pd: X = Cl(16a); M = Pt: X = Cl(17a), Br(18a)] species in CDCl3 with PPh3 + SnX2 has been explored to establish the factors that influence the nature of the products. With the mononuclear precursors the course of the reaction is strongly dependent on the tripodal or linear arrangement of the polydentate ligand and in the former case on the halogen. Thus, while for chlorides (1a-2a, 7a-8a) and bromides (3a-4a) the reaction led to the trigonal-bipyramidal compounds [M(SnCl3)(AP3)][SnCl3] [A = P: M = Pd(1), Pt(2); A = N: M = Pd(7), Pt(8)], [MBr(PP3)][SnBr3] [M = Pd(4), Pt(6)] containing M-Sn and M-Br bonds, respectively, for iodides (5a-6a) resulted in the unknown neutral square-planar compounds [MI2(PP(PO)2)(SnI2)2] [M = Pd(9) and Pt(10)] bearing two dangling P=O-SnI2 units and P2MI2 environments. However, complexes of the type [PtCl(PP2PO)X]X' [X = SnCl2, X' = [SnCl3](-)(11)] and [M(PP(PO)2)2X4]X'2 [X = SnCl2, X' = [SnCl3](-): M = Pd(12), Pt(13)] showing P=O-SnCl2 arms were obtained by direct reaction of [PtCl(PP2PO)]Cl (11a) and [M(PP(PO)2)2]Cl2 [M = Pd(12a), Pt(13a)] with SnCl2 in CH3OH. Although complex 9 was also prepared by interaction of the heteronuclear iodide 9a with PPh3 + SnI2 in CDCl3, the use of the neutral and ionic heteronuclear chlorides and bromides (14a-18a) as starting materials afforded the distorted square-planar ionic systems [MAuX'(PP3)(PPh3)][SnX3]2 [M = Pd: X = Cl, X' = SnCl3(-)(14); X = Br, X' = SnBr3(-)(15); M = Pt: X = Cl, X' = SnCl3(-)(17); X = Br, X' = SnBr3(-)(18)] containing M-SnX3 and P-Au-PPh3 functionalities. It was found that these reactions where the heteronuclear species are the precursors proceed via the trigonal-bipyramidal halides not only with X = Cl and Br(1a-4a) but also I(5a). When the precursors were 10a and 10b the reaction occurred with formation of [Pd(PNP)(PPh3)][SnCl3]2 (23) and [Pt(PNP)(PPh3)][SnCl2I]2 (24) showing M-PPh3 units and trihalostannato counter anions.

Self-assembled SnO2 micro- and nanosphere-based gas sensor thick films from an alkoxide-derived high purity aqueous colloid precursor

NASA Astrophysics Data System (ADS)

Kelp, G.; Tätte, T.; Pikker, S.; Mändar, H.; Rozhin, A. G.; Rauwel, P.; Vanetsev, A. S.; Gerst, A.; Merisalu, M.; Mäeorg, U.; Natali, M.; Persson, I.; Kessler, V. G.

2016-03-01

Tin oxide is considered to be one of the most promising semiconductor oxide materials for use as a gas sensor. However, a simple route for the controllable build-up of nanostructured, sufficiently pure and hierarchical SnO2 structures for gas sensor applications is still a challenge. In the current work, an aqueous SnO2 nanoparticulate precursor sol, which is free of organic contaminants and sorbed ions and is fully stable over time, was prepared in a highly reproducible manner from an alkoxide Sn(OR)4 just by mixing it with a large excess of pure neutral water. The precursor is formed as a separate liquid phase. The structure and purity of the precursor is revealed using XRD, SAXS, EXAFS, HRTEM imaging, FTIR, and XRF analysis. An unconventional approach for the estimation of the particle size based on the quantification of the Sn-Sn contacts in the structure was developed using EXAFS spectroscopy and verified using HRTEM. To construct sensors with a hierarchical 3D structure, we employed an unusual emulsification technique not involving any additives or surfactants, using simply the extraction of the liquid phase, water, with the help of dry butanol under ambient conditions. The originally generated crystalline but yet highly reactive nanoparticles form relatively uniform spheres through self-assembly and solidify instantly. The spheres floating in butanol were left to deposit on the surface of quartz plates bearing sputtered gold electrodes, producing ready-for-use gas sensors in the form of ca. 50 μm thick sphere-based-films. The films were dried for 24 h and calcined at 300 °C in air before use. The gas sensitivity of the structures was tested in the temperature range of 150-400 °C. The materials showed a very quickly emerging and reversible (20-30 times) increase in electrical conductivity as a response to exposure to air containing 100 ppm of H2 or CO and short (10 s) recovery times when the gas flow was stopped.Tin oxide is considered to be one of the most promising semiconductor oxide materials for use as a gas sensor. However, a simple route for the controllable build-up of nanostructured, sufficiently pure and hierarchical SnO2 structures for gas sensor applications is still a challenge. In the current work, an aqueous SnO2 nanoparticulate precursor sol, which is free of organic contaminants and sorbed ions and is fully stable over time, was prepared in a highly reproducible manner from an alkoxide Sn(OR)4 just by mixing it with a large excess of pure neutral water. The precursor is formed as a separate liquid phase. The structure and purity of the precursor is revealed using XRD, SAXS, EXAFS, HRTEM imaging, FTIR, and XRF analysis. An unconventional approach for the estimation of the particle size based on the quantification of the Sn-Sn contacts in the structure was developed using EXAFS spectroscopy and verified using HRTEM. To construct sensors with a hierarchical 3D structure, we employed an unusual emulsification technique not involving any additives or surfactants, using simply the extraction of the liquid phase, water, with the help of dry butanol under ambient conditions. The originally generated crystalline but yet highly reactive nanoparticles form relatively uniform spheres through self-assembly and solidify instantly. The spheres floating in butanol were left to deposit on the surface of quartz plates bearing sputtered gold electrodes, producing ready-for-use gas sensors in the form of ca. 50 μm thick sphere-based-films. The films were dried for 24 h and calcined at 300 °C in air before use. The gas sensitivity of the structures was tested in the temperature range of 150-400 °C. The materials showed a very quickly emerging and reversible (20-30 times) increase in electrical conductivity as a response to exposure to air containing 100 ppm of H2 or CO and short (10 s) recovery times when the gas flow was stopped. Electronic supplementary information (ESI) available: IR spectrum of additives found in the residual butanol layer formed during precursor preparation. See DOI: 10.1039/c5nr07942j

A mechanistic investigation of ethylene oxide hydrolysis to ethanediol.

PubMed

Lundin, Angelica; Panas, Itai; Ahlberg, Elisabet

2007-09-20

The B3LYP/6-311+G(d,p) description is employed to study the heterolytic ring opening mechanisms under microsolvation conditions for ethylene oxide in acidic, neutral, and alkaline environments. In acid and alkaline media, a concerted trans S(N)2 reaction is strongly favored as compared to the corresponding cis reaction. The importance of the nucleophile, water in acidic media and hydroxide ion in alkaline media, for lowering the activation enthalpy is emphasized and activation energies of approximately 80 and approximately 60 kJ mol(-1) are obtained under acid and alkaline conditions, respectively. Under neutral conditions, the trans S(N)2 mechanism becomes inaccessible because it invokes the formation of a transient H+ and OH- pair across the 1,2-ethanediol molecule. Rather, epoxide ring opening is achieved by hydrolysis of a single water molecule. The latter mechanism displays significantly greater activation enthalpy (205 kJ mol(-1)) than those in acid and alkaline environments. This is in agreement with experiment. Product distributions of simple olefins in neutral aqueous media, as well as the detrimental impact of acid/base conditions for the selectivity of epoxidation catalysts in aqueous media, are discussed.

Functionalized graphene oxides for drug loading, release and delivery of poorly water soluble anticancer drug: A comparative study.

PubMed

Karki, Neha; Tiwari, Himani; Pal, Mintu; Chaurasia, Alok; Bal, Rajaram; Joshi, Penny; Sahoo, Nanda Gopal

2018-05-18

In this work, the modification of graphene oxides (GOs) have been done with hydrophilic and biodegradable polymer, polyvinylpyrrolidone (PVP) and other excipient β -cyclodextrin (β-CD) through covalent functionalization for efficient loading and compatible release of sparingly water soluble aromatic anticancer drug SN-38 (7-ethyl-10-hydroxy camptothecin). The drug was loaded onto both GO-PVP and GO-β-CD through the π-π interactions.The release of drug from both the nanocarriers were analyzed in different pH medium of pH 7 (water, neutral medium), pH 5 (acidic buffer) and pH 12 (basic buffer). The loading capacity and the cell killing activity of SN-38 loaded on functionalized GO were investigated comprehensively in human breast cancer cells MCF-7.Our findings shown that the cytotoxicity of SN-38 loaded to the polymer modified GO was comparatively higher than free SN-38. In particular, SN-38 loaded GO-PVP nanocarrier has more cytotoxic effect than GO-β-CD nanocarrier against MCF-7 cells, indicating that SN-38 loaded GO-PVP nanocarrier can be used as promising material for drug delivery and biological applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Bonding Properties of a Novel Inorganometallic Complex, Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) (iPr-DAB = N,N'-Diisopropyl-1,4-diaza-1,3-butadiene), and its Stable Radical-Anion, Studied by UV-Vis, IR, and EPR Spectroscopy, (Spectro-) Electrochemistry, and Density Functional Calculations.

PubMed

Aarnts, Maxim P.; Wilms, Maikel P.; Peelen, Karin; Fraanje, Jan; Goubitz, Kees; Hartl, Frantisek; Stufkens, Derk J.; Baerends, Evert Jan; Vlcek, Antonín

1996-09-11

Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) was synthesized and characterized by UV-vis, IR, (1)H NMR, (13)C NMR, (119)Sn NMR, and mass (FAB(+)) spectroscopies and by single-crystal X-ray diffraction, which proved the presence of a nearly linear Sn-Ru-Sn unit. Crystals of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB).3.5C(6)H(6) form in the triclinic space group P&onemacr; in a unit cell of dimensions a = 11.662(6) Å, b = 13.902(3) Å, c = 19.643(2) Å, alpha = 71.24(2) degrees, beta = 86.91(4) degrees, gamma = 77.89(3) degrees, and V = 2946(3) Å(3). One-electron reduction of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) produces the stable radical-anion [Ru(SnPh(3))(2)(CO)(2)(iPr-DAB)](*-) that was characterized by IR, and UV-vis spectroelectrochemistry. Its EPR spectrum shows a signal at g = 1.9960 with well resolved Sn, Ru, and iPr-DAB (H, N) hyperfine couplings. DFT-MO calculations on the model compound Ru(SnH(3))(2)(CO)(2)(H-DAB) reveal that the HOMO is mainly of sigma(Sn-Ru-Sn) character mixed strongly with the lowest pi orbital of the H-DAB ligand. The LUMO (SOMO in the reduced complex) should be viewed as predominantly pi(H-DAB) with an admixture of the sigma(Sn-Ru-Sn) orbital. Accordingly, the lowest-energy absorption band of the neutral species will mainly belong to the sigma(Sn-Ru-Sn)-->pi(iPr-DAB) charge transfer transition. The intrinsic strength of the Ru-Sn bond and the delocalized character of the three-center four-electron Sn-Ru-Sn sigma-bond account for the inherent stability of the radical anion.

A novel sol-gel-derived calcium silicate cement with short setting time for application in endodontic repair of perforations

PubMed Central

Lee, Bor-Shiunn; Lin, Hong-Ping; Chan, Jerry Chun-Chung; Wang, Wei-Chuan; Hung, Ping-Hsuan; Tsai, Yu-Hsin; Lee, Yuan-Ling

2018-01-01

Mineral trioxide aggregate (MTA) is the most frequently used repair material in endodontics, but the long setting time and reduced mechanical strength in acidic environments are major shortcomings. In this study, a novel sol-gel-derived calcium silicate cement (sCSC) was developed using an initial Ca/Si molar ratio of 3, with the most effective mixing orders of reactants and optimal HNO3 catalyst volumes. A Fourier transform infrared spectrometer, scanning electron microscope with energy-dispersive X-ray spectroscopy, and X-ray powder diffractometer were used for material characterization. The setting time, compressive strength, and microhardness of sCSC after hydration in neutral and pH 5 environments were compared with that of MTA. Results showed that sCSC demonstrated porous microstructures with a setting time of ~30 min, and the major components of sCSC were tricalcium silicate, dicalcium silicate, and calcium oxide. The optimal formula of sCSC was sn200, which exhibited significantly higher compressive strength and microhardness than MTA, irrespective of neutral or pH 5 environments. In addition, both sn200 and MTA demonstrated good biocompatibility because cell viability was similar to that of the control. These findings suggest that sn200 merits further clinical study for potential application in endodontic repair of perforations. PMID:29386894

A novel sol-gel-derived calcium silicate cement with short setting time for application in endodontic repair of perforations.

PubMed

Lee, Bor-Shiunn; Lin, Hong-Ping; Chan, Jerry Chun-Chung; Wang, Wei-Chuan; Hung, Ping-Hsuan; Tsai, Yu-Hsin; Lee, Yuan-Ling

2018-01-01

Mineral trioxide aggregate (MTA) is the most frequently used repair material in endodontics, but the long setting time and reduced mechanical strength in acidic environments are major shortcomings. In this study, a novel sol-gel-derived calcium silicate cement (sCSC) was developed using an initial Ca/Si molar ratio of 3, with the most effective mixing orders of reactants and optimal HNO 3 catalyst volumes. A Fourier transform infrared spectrometer, scanning electron microscope with energy-dispersive X-ray spectroscopy, and X-ray powder diffractometer were used for material characterization. The setting time, compressive strength, and microhardness of sCSC after hydration in neutral and pH 5 environments were compared with that of MTA. Results showed that sCSC demonstrated porous microstructures with a setting time of ~30 min, and the major components of sCSC were tricalcium silicate, dicalcium silicate, and calcium oxide. The optimal formula of sCSC was sn200, which exhibited significantly higher compressive strength and microhardness than MTA, irrespective of neutral or pH 5 environments. In addition, both sn200 and MTA demonstrated good biocompatibility because cell viability was similar to that of the control. These findings suggest that sn200 merits further clinical study for potential application in endodontic repair of perforations.

Correlations of charge neutrality level with electronic structure and p-d hybridization

PubMed Central

Das, Arkaprava; Gautam, Subodh K.; Shukla, D. K.; Singh, Fouran

2017-01-01

The formation of charge neutrality level (CNL) in highly conducting Cadmium oxide (CdO) thin films is demonstarted by the observed variation in the band gap upon annealing and doping. It may be explained by the observation that Tin (Sn) doping breaks the perfect periodicity of CdO cubic crystal structure and creates virtual gap states (ViGS). The level of local CNL resides at the branch point of ViGS, making the energy at which native defect’s character changes from predominantly donor-like below CNL to predominantly acceptor-like above the CNL and a schematic band diagram is developed to substantiate the same. Further investigations using soft x-ray absorption spectroscopy (SXAS) at Oxygen and Cadmium edges show the reduction of Sn4+ to Sn2+. The analysis of the spectral features has revealed an evidence of p-d interaction between O 2p and Cd 4d orbitals that pushes the valence band minima at higher energies which is symmetry forbidden at г point and causing a positive valance band dispersion away from the zone centre in the г ~ L, K direction. Thus, origin of the CNL is attributed to the high density of the Oxygen vacancies as confirmed by the change in the local electronic structure and p-d hybridization of orbitals. PMID:28102312

Correlations of charge neutrality level with electronic structure and p-d hybridization

NASA Astrophysics Data System (ADS)

Das, Arkaprava; Gautam, Subodh K.; Shukla, D. K.; Singh, Fouran

2017-01-01

The formation of charge neutrality level (CNL) in highly conducting Cadmium oxide (CdO) thin films is demonstarted by the observed variation in the band gap upon annealing and doping. It may be explained by the observation that Tin (Sn) doping breaks the perfect periodicity of CdO cubic crystal structure and creates virtual gap states (ViGS). The level of local CNL resides at the branch point of ViGS, making the energy at which native defect’s character changes from predominantly donor-like below CNL to predominantly acceptor-like above the CNL and a schematic band diagram is developed to substantiate the same. Further investigations using soft x-ray absorption spectroscopy (SXAS) at Oxygen and Cadmium edges show the reduction of Sn4+ to Sn2+. The analysis of the spectral features has revealed an evidence of p-d interaction between O 2p and Cd 4d orbitals that pushes the valence band minima at higher energies which is symmetry forbidden at г point and causing a positive valance band dispersion away from the zone centre in the г ~ L, K direction. Thus, origin of the CNL is attributed to the high density of the Oxygen vacancies as confirmed by the change in the local electronic structure and p-d hybridization of orbitals.

Non-LTE spectral analysis and model constraints on SN 1993J

NASA Technical Reports Server (NTRS)

Baron, E.; Hauschildt, P. H.; Branch, D.; Austin, S.; Garnavich, P.; Ann, Hong Bae; Wagner, R. M.; Filippenko, A. V.; Matheson, T.; Liebert, James

1995-01-01

We present non-Local Thermodynamic Equilibrium (LTE) synthetic spectra for a time series of observations of SN 1993J obtained on 1993 March 30-31, April 7, April 13-15, and June 13 UT. The spectra are dominated by hydrogen Balmer lines; neutral helium lines, which have been nonthermally excited; and Fe II features. The density profile evolves from an extremely steep 'brick wall' structure with an equivalent power-law index of about 50 on March 30 to a more typical SN II profile with a power law index of about 10. The early spectra are well fitted by a solar composition of metals, although an enhanced abundance of helium is required in order to fit the neutral helium lines. By June 13, the photosphere has receded deep into the helium layer, although there appears to be a layer of hydrogen at higher velocity. The distance is estimated for each epoch. While consistent results are found for spectra obtained in the month of April, the spread in distances from March to June is quite large. Our value for April is mu = 28.0 +/- 0.3 mag, consistent with the recent Cepheid distance to the host galaxy M81. We also compare our results to other implementations of the expanding photosphere method.

Atomic structure considerations for the low-temperature opacity of Sn

DOE PAGES

Colgan, J.; Kilcrease, D. P.; Abdallah, J.; ...

2017-03-31

Here, we have begun a preliminary investigation into the opacity of Sn at low temperatures (< 50 eV). The emissivity and opacity of Sn is a crucial factor in determining the utility of Sn in EUV lithography, with numerous industrial implications. To this end, we have been exploring the accuracy of some approximations used in opacity models for the relevant ion stages of Sn (neutral through ~ 18 times ionized). We also find that the use of intermediate-coupling, as compared to full configuration-interaction, is not adequate to obtain accurate line positions of the important bound-bound transitions in Sn. One requiresmore » full configuration-interaction to properly describe the strong mixing between the various n=4 sub-shells that give rise to the Δn= 0 transitions that dominate the opacity spectrum at low temperatures. Furthermore, since calculations that include full configuration-interaction for large numbers of configurations quickly become computationally prohibitive, we have explored hybrid calculations, in which full configuration-interaction is retained for the most important transitions, while intermediate-coupling is employed for all other transitions. After extensive exploration of the atomic structure properties, local-thermodynamic-equilibrium (LTE) opacities are generated using the ATOMIC code at selected temperatures and densities and compared to experiment.« less

Atomic structure considerations for the low-temperature opacity of Sn

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

Colgan, J.; Kilcrease, D. P.; Abdallah, J.

Here, we have begun a preliminary investigation into the opacity of Sn at low temperatures (< 50 eV). The emissivity and opacity of Sn is a crucial factor in determining the utility of Sn in EUV lithography, with numerous industrial implications. To this end, we have been exploring the accuracy of some approximations used in opacity models for the relevant ion stages of Sn (neutral through ~ 18 times ionized). We also find that the use of intermediate-coupling, as compared to full configuration-interaction, is not adequate to obtain accurate line positions of the important bound-bound transitions in Sn. One requiresmore » full configuration-interaction to properly describe the strong mixing between the various n=4 sub-shells that give rise to the Δn= 0 transitions that dominate the opacity spectrum at low temperatures. Furthermore, since calculations that include full configuration-interaction for large numbers of configurations quickly become computationally prohibitive, we have explored hybrid calculations, in which full configuration-interaction is retained for the most important transitions, while intermediate-coupling is employed for all other transitions. After extensive exploration of the atomic structure properties, local-thermodynamic-equilibrium (LTE) opacities are generated using the ATOMIC code at selected temperatures and densities and compared to experiment.« less

Spin-orbit coupling and surface magnetism coexisting in spin-dependent low-energy He+-ion surface scattering

NASA Astrophysics Data System (ADS)

Suzuki, T. T.; Sakai, O.

2017-04-01

Surface magnetism is analyzed by spin-dependent He+-ion neutralization (the Auger neutralization) in the vicinity of a surface using an electron spin-polarized low-energy He+-ion beam [spin-polarized ion scattering spectroscopy (SP-ISS)]. Recently, spin-orbit coupling (SOC) has been found to act as another mechanism of spin-dependent low-energy He+-ion scattering. Thus, it is crucial for surface magnetism analyses by SP-ISS to separate those two mechanisms. In the present study, we investigated the spin-induced asymmetry in scattering of low-energy He+ ions on ultrathin Au and Sn films as well as the oxygen adsorbate on a magnetized-Fe(100) surface where these two mechanisms may coexist. We found that the Fe surface magnetism immediately disappeared with the growth of those overlayers. On the other hand, we observed no induced spin polarization in the Au and Sn thin films even in the very initial stage of the growth. We also observed that the spin asymmetry of the O adsorbate was induced by the magnetism of the underlying Fe substrate. The present study demonstrates that the two mechanisms of the spin-asymmetric He+-ion scattering (the ion neutralization and SOC) can be separated by an azimuthal-angle-resolved SP-ISS measurement.

Microstructure, Tensile Properties, and Corrosion Behavior of Die-Cast Mg-7Al-1Ca- xSn Alloys

NASA Astrophysics Data System (ADS)

Wang, Feng; Dong, Haikuo; Sun, Shijie; Wang, Zhi; Mao, Pingli; Liu, Zheng

2018-02-01

The microstructure, tensile properties, and corrosion behavior of die-cast Mg-7Al-1Ca- xSn ( x = 0, 0.5, 1.0, and 2.0 wt.%) alloys were studied using OM, SEM/EDS, tensile test, weight loss test, and electrochemical test. The experimental results showed that Sn addition effectively refined grains and intermetallic phases and increased the amount of intermetallic phases. Meanwhile, Sn addition to the alloys suppressed the formation of the (Mg,Al)2Ca phase and resulted in the formation of the ternary CaMgSn phase and the binary Mg2Sn phase. The Mg-7Al-1Ca-0.5Sn alloy exhibited best tensile properties at room temperature, while Mg-7Al-1Ca-1.0Sn alloy exhibited best tensile properties at elevated temperature. The corrosion resistance of studied alloys was improved by the Sn addition, and the Mg-7Al-1Ca-0.5Sn alloy presented the best corrosion resistance.

Reionization and CMB non-Gaussianity

NASA Astrophysics Data System (ADS)

Munshi, D.; Corasaniti, P. S.; Coles, P.; Heavens, A.; Pandolfi, S.

2014-08-01

We show how cross-correlating a high-redshift external tracer field, such as the 21-cm neutral hydrogen distribution and product maps involving cosmic microwave background (CMB) temperature and polarization fields, that probe mixed bispectrum involving these fields, can help to determine the reionization history of the Universe, beyond what can be achieved from cross-spectrum analysis. Taking clues from recent studies for the detection of primordial non-Gaussianity, we develop a set of estimators that can study reionization using a power spectrum associated with the bispectrum (or skew-spectrum). We use the matched filtering inherent in this method to investigate different reionization histories. We check to what extent they can be used to rule out various models of reionization and study cross-contamination from different sources such as the lensing of the CMB. The estimators can be fine-tuned to optimize study of a specific reionization history. We consider three different types of tracers in our study, namely: proto-galaxies; 21-cm maps of neutral hydrogen; and quasars. We also consider four alternative models of reionization. We find that the cumulative signal-to-noise ratio (S/N) for detection at ℓmax = 2000 can reach O(70) for cosmic variance limited all-sky experiments. Combining 100 GHz, 143 GHz and 217 GHz channels of the Planck experiment, we find that the S/N lies in the range O(5)-O(35). The S/N depends on the specific choice of a tracer field, and multiple tracers can be effectively used to map out the entire reionization history with reasonable S/N. Contamination from weak lensing is investigated and found to be negligible, and the effects of Thomson scattering from patchy reionization are also considered.

Physicochemical characterization of point defects in fluorine doped tin oxide films

NASA Astrophysics Data System (ADS)

Akkad, Fikry El; Joseph, Sudeep

2012-07-01

The physical and chemical properties of spray deposited FTO films are studied using FESEM, x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), electrical and optical measurements. The results of XRD measurements showed that the films are polycrystalline (grain size 20-50 nm) with Rutile structure and mixed preferred orientation along the (200) and (110) planes. An angular shift of the XRD peaks after F-doping is observed and interpreted as being due to the formation of substitutional fluorine defects (FO) in presence of high concentration of oxygen vacancies (VO) that are electrically neutral. The electrical neutrality of oxygen vacancies is supported by the observation that the electron concentration n is two orders of magnitude lower than the VO concentration calculated from chemical analyses using XPS measurements. It is shown that an agreement between XPS, XRD, and Hall effect results is possible provided that the degree of deviation from stoichiometry is calculated with the assumption that the major part of the bulk carbon content is involved in O-C bonds. High temperature thermal annealing is found to cause an increase in the FO concentration and a decrease in both n and VO concentrations with the increase of the annealing temperature. These results could be interpreted in terms of a high temperature chemical exchange reaction between the SnO2 matrix and a precipitated fluoride phase. In this reaction, fluorine is released to the matrix and Sn is trapped by the fluoride phase, thus creating substitutional fluorine FO and tin vacancy VSn defects. The enthalpy of this reaction is determined to be approximately 2.4 eV while the energy of formation of a VSn through the migration of SnSn host atom to the fluoride phase is approximately 0.45 eV.

Abundances of Neutral and Ionized PAH Along The Lines-of-Sight of Diffuse and Translucent Interstellar Clouds

NASA Technical Reports Server (NTRS)

Salama, Farid; Galazutdinov, Gazinur; Krewloski, Jacek; Biennier, Ludovic; Beletsky, Yuri; Song, In-Ok

2013-01-01

The spectra of neutral and ionized PAHs isolated in the gas phase at low temperature have been measured in the laboratory under conditions that mimic interstellar conditions and are compared with a set of astronomical spectra of reddened, early type stars. The comparisons of astronomical and laboratory data provide upper limits for the abundances of neutral PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations. We present the characteristics of the laboratory facility (COSmIC) that was developed for this study and discuss the findings resulting from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. COSmIC combines a supersonic jet expansion with discharge plasma and cavity ringdown spectroscopy and provides experimental conditions that closely mimic the interstellar conditions. The column densities of the individual PAH molecules and ions probed in these surveys are derived from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. The comparisons of astronomical and laboratory data lead to clear conclusions regarding the expected abundances for PAHs in the interstellar environments probed in the surveys. Band profile comparisons between laboratory and astronomical spectra lead to information regarding the molecular structures and characteristics associated with the DIB carriers in the corresponding lines-of-sight. These quantitative surveys of neutral and ionized PAHs in the optical range open the way for quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments.

An asymmetric energetic type Ic supernova viewed off-axis, and a link to gamma ray bursts.

PubMed

Mazzali, Paolo A; Kawabata, Koji S; Maeda, Keiichi; Nomoto, Ken'ichi; Filippenko, Alexei V; Ramirez-Ruiz, Enrico; Benetti, Stefano; Pian, Elena; Deng, Jinsong; Tominaga, Nozomu; Ohyama, Youichi; Iye, Masanori; Foley, Ryan J; Matheson, Thomas; Wang, Lifan; Gal-Yam, Avishay

2005-05-27

Type Ic supernovae, the explosions after the core collapse of massive stars that have previously lost their hydrogen and helium envelopes, are particularly interesting because of their link with long-duration gamma ray bursts. Although indications exist that these explosions are aspherical, direct evidence has been missing. Late-time observations of supernova SN 2003jd, a luminous type Ic supernova, provide such evidence. Recent Subaru and Keck spectra reveal double-peaked profiles in the nebular lines of neutral oxygen and magnesium. These profiles are different from those of known type Ic supernovae, with or without a gamma ray burst, and they can be understood if SN 2003jd was an aspherical axisymmetric explosion viewed from near the equatorial plane. If SN 2003jd was associated with a gamma ray burst, we missed the burst because it was pointing away from us.

White dwarf stars exceeding the Chandrasekhar mass limit

NASA Astrophysics Data System (ADS)

Tomaschitz, Roman

2018-01-01

The effect of nonlinear ultra-relativistic electron dispersion on the mass-radius relation of high-mass white dwarfs is studied. The dispersion is described by a permeability tensor in the Dirac equation, generated by the ionized high-density stellar matter, which constitutes the neutralizing background of the nearly degenerate electron plasma. The electron dispersion results in a stable mass-radius relation for high-mass white dwarfs, in contrast to a mass limit in the case of vacuum permeabilities. In the ultra-relativistic regime, the dispersion relation is a power law whose amplitude and scaling exponent is inferred from mass and radius estimates of two high-mass white dwarfs, Sirius B and LHS 4033. Evidence for the existence of super-Chandrasekhar mass white dwarfs is provided by several Type Ia supernovae (e.g., SN 2013cv, SN 2003fg, SN 2007if and SN 2009dc), whose mass ejecta exceed the Chandrasekhar limit by up to a factor of two. The dispersive mass-radius relation is used to estimate the radii, central densities, Fermi temperatures, bulk and compression moduli and sound velocities of their white dwarf progenitors.

Experimental and DFT study of cyclodehydration and acetylation of ferrocenyl diols

NASA Astrophysics Data System (ADS)

Lapić, Jasmina; Višnjevac, Aleksandar; Cetina, Mario; Djaković, Senka; Vrček, Valerije; Rapić, Vladimir

2012-07-01

Racemic ferrocenyl diols, i.e. ferrocenyl(2-hydroxymethylphenyl)methanol (2), ferrocenyl-2-(2-hydroxymethylphenyl)ethanol (7), and ferrocenyl(2-(2-hydroxyethyl)phenyl)methanol (9) have been prepared by reduction of corresponding ketoesters using NaBH4 in a mixture EtOH and Et2O. In the course of these reactions new cyclic ethers 1-ferrocenyl-2-oxaindane (3), 3-ferrocenylisochromane (8), and 1-ferrocenylisochromane (10) have been isolated as side-products. Intramolecular cyclizations of ferrocenyl diols occur in both acidic and neutral medium. Density functional theory (BP86) calculations were used to explain the mechanism of these cyclodehydrations. Acid catalyzed reaction follows the classical SN1 mechanism, whereas the cyclodehydration in neutral medium is described as an SN2 reaction. X-ray diffraction analysis of new cyclic ether products has been performed. Monoacetates 11, 13 and 15 have been obtained in the reaction of ferrocenyl diols 2, 7, and 9, respectively, and acetic anhydride. Stereoselective acylation of racemic diols by vinyl acetate have been catalyzed by various lipases, and the best stereoselectivity has been observed for the diol 2 in the presence of Penicillium camembertii lipase.

X-ray Emission from Supernovae in Dense Circumstellar Matter Environments: a Search for Collisionless Shocks

NASA Technical Reports Server (NTRS)

Ofek, E. O.; Fox, D.; Cenko, Stephen B.; Sullivan, M; Gnat, O.; Frail, D. A.; Horesh, A.; Corsi, A.; Quimby, R. M.; Gehrels, N.;

Effect of the Silver Content of SnAgCu Solder on the Interfacial Reaction and on the Reliability of Angle Joints Fabricated by Laser-Jet Soldering

NASA Astrophysics Data System (ADS)

Ji, Hongjun; Ma, Yuyou; Li, Mingyu; Wang, Chunqing

2015-02-01

The silver content of lead-free solders affects their microstructure, the interfacial reaction, and the performance of the joints in reliability tests. In this study, Sn3.0Ag0.5Cu (wt.%, SAC305) and Sn1.0Ag0.5Cu (wt.%, SAC105) solder balls of diameter 55 μm were reflowed on gold surface pads by laser-jet soldering. It was found that four types of layered intermetallic compound (IMC) were formed at the interfaces; these were Au5Sn/AuSn, AuSn, AuSn2, and AuSn4 from the pad side to the solder matrix. The Au5Sn/AuSn eutectic region, thickness 400 nm, formed because of the high cooling rate induced by the laser-jet soldering. During high-temperature storage tests, the silver became segregated at the interfaces between the Au-Sn IMC and the solder matrix, resulting in inhibition of IMC growth in SAC305 joints, the shear strengths of which were higher than those of SAC105 joints. In mechanical drop tests, however, percentage failure of the SAC305 joints was twice that of the SAC105 joints.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A): Engineering Test Report: METSAT A2 Signal Processor (P/N 1331120-2, S/N F03) S/N 107

NASA Technical Reports Server (NTRS)

1998-01-01

This report presents a description of the tests performed, and the test data, for the A2 METSAT Signal Processor Assembly PN: 1331120-2, S/N F03. The assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure."

Integrated Advanced Microwave Sounding Unit-A (AMSU-A): Engineering Test Report, METSAT A2 Signal Processor (P/N 1331120-2, S/N F04) S/N 108

NASA Technical Reports Server (NTRS)

1998-01-01

This report presents a description of the tests performed, and the test data, for the A2 METSAT Signal Processor Assembly PN: 1331120-2, S/N F04. The assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure."

N-HO and N-HCl supported 1D chains of heterobimetallic CuII/NiII-SnIV cocrystals.

PubMed

Hazra, Susanta; Meyrelles, Ricardo; Charmier, Adilia Januário; Rijo, Patrícia; Guedes da Silva, M Fátima C; Pombeiro, Armando J L

2016-11-28

The Schiff base H 2 L 1 [N,N'-ethylenebis(3-methoxysalicylaldimine)] or H 2 L 2 [N,N'-ethylenebis(3-ethoxysalicylaldimine)] was reacted with MCl 2 ·xH 2 O and SnCl 4 ·5H 2 O to afford the supramolecular heterobimetallic systems (H 2 ED) 2+ ·2[ML]·[SnCl 6 ] 2- [M = Cu, L = L 1 (1), L = L 2 (2); M = Ni, L = L 1 (3), L = L 2 (4); ED = 1,2-ethylenediamine], whose structures were established by single crystal X-ray analyses. Each structure includes different entities, viz. a mononuclear [CuL]/[NiL] neutral complex (coformer), a hexachlorostannate dianion [SnCl 6 ] 2- , a 1,2-ethylenediammonium dication (H 2 ED 2+ ) and, only in 2 and 4, a methanol molecule. Based on the work of Grothe et al. (Cryst. Growth Des., 2016, 16, 3237-3243), compounds 1 and 3 are cocrystal salts, 2 and 4 are cocrystal salt solvates. The ionic pairs (H 2 ED) 2+ ·[SnCl 6 ] 2- in 1-4 are encapsulated by the Cu- or Ni-complexes, and stabilized by N-HO and one N-HCl bond interactions leading to infinite 1D chains. The antimicrobial studies of 1-4 against yeasts (C. albicans and S. cerevisiae) and Gram-positive (S. aureus and E. faecalis) and -negative bacteria (P. aeruginosa and E. coli) indicate that the Ni 2 Sn systems (3 and 4) are more active than the analogous Cu 2 Sn ones (1 and 2).

X-Ray Emission from Supernovae in Dense Circumstellar Matter Environments: A Search for Collisionless Shock

NASA Technical Reports Server (NTRS)

Ofek, E.O; Fox, D.; Cenko, B.; Sullivan, M.; Gnat, O.; Frail A.; Horesh, A.; Corsi, A; Quimby, R. M.; Gehrels, N.;

Lipidomic profile in three species of dinoflagellates (Amphidinium carterae, Cystodinium sp., and Peridinium aciculiferum) containing very long chain polyunsaturated fatty acids.

PubMed

Řezanka, Tomáš; Lukavský, Jaromír; Nedbalová, Linda; Sigler, Karel

2017-07-01

This study describes the identification of very long chain polyunsaturated fatty acids (VLCPUFAs) in three strains of dinoflagellates (Amphidinium carterae, Cystodinium sp., and Peridinium aciculiferum). The strains were cultivated and their lipidomic profiles were obtained by high resolution mass spectrometry with the aid of positive and negative electrospray ionization (ESI) mode by Orbitrap apparatus. Hydrophilic interaction liquid chromatography (HILIC/ESI) was used to separate major lipid classes of the three genera of dinoflagellates by neutral loss scan showing the ion [M + H-28:8] + , where 28:8 was octacosaoctaenoic acid, and by precursor ion scanning of ions at m/z 407, which was an ion corresponding to the structure of acyl of 28:8 acid (C 27 H 39 COO - ). Based on these analyzes, it was found that out of more than a dozen lipid classes present in the total lipids, only two classes of neutral lipids, i.e. major triacylglycerols and minor diacylglycerols contain VLCPUFAs. In polar lipids, VLCPUFAs were identified only in phosphatidic acid (PA) and phosphatidyl choline (PC) or in their lyso-forms (LPA and LPC). Further analysis of individual lipid classes by reversed-phase high-performance liquid chromatography (RP-HPLC) showed the presence of triacylglycerols (TAGs) containing VLCPUFAs, i.e. molecular species of the sn-28:7/28:8/28:8, sn-26:7/28:7/28:8, or sn-26:7/28:8/28:8 types. These TAGs are the longest and most unsaturated TAGs isolated from a natural source that have yet been synthesized. In the case of PA and PC, tandem MS identified sn-28:8/16:0-PA and sn-28:8/16:0-PC and the corresponding lyso-forms (28:8-LPC and 28:8-LPA). All these results indicate that TAGs containing VLCPUFAs are biosynthesized in dinoflagellates in the same manner as in higher eukaryotic organisms, which means that the PA, after conversion to DAG, serves as a precursor in the biosynthesis of other phospholipids, e.g. PC, and, after further acylation, also of TAG. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of the bacillus of Calmette-Guérin, Propionibacter acnes and avridine as immunomodulators in antirabies vaccination of mice using the Fuenzalida-Palacios mouse brain vaccine.

PubMed

Megid, J; Peraçolli, M T; Curi, P R; Zanetti, C R; Cabrera, W H; Vassao, R; Ito, F H

1999-05-14

Using the laboratory mice, Fuenzalida-Palacios mouse brain human rabies vaccine was administered in groups of animals previously inoculated with rabies virus and then submitted to treatments with the immunomodulators onco-BCG, avridine and Propionibacterium acnes. Humoral and cellular immune responses were evaluated through the macrophage inhibition factor (MIF), intra-pad inoculation (IPI) and serum neutralization (SN) tests and by the detection of gamma-interferon (IFN-gamma). The IPI test was not effective in detecting the response of delayed-type hypersensitivity, contrary to MIF, which showed the immune cellular response. Higher levels of IFN-gamma were observed in the groups of mice vaccinated and treated with avridine and P. acnes. Although immunomodulating activities have been detected, the use of adjuvants with the Fuenzalida-Palacios type vaccine in mice did not reveal any encouraging results.

Scanning tunneling microscope observation of the phosphatidylserine domains in the phosphatidylcholine monolayer.

PubMed

Matsunaga, Soichiro; Yamada, Taro; Kobayashi, Toshihide; Kawai, Maki

2015-05-19

A mixed monolayer of 1,2-dihexanoyl-sn-glycero-3-phospho-l-serine (DHPS) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) on an 1-octanethiol-modified gold substrate was visualized on the nanometer scale using in situ scanning tunneling microscopy (STM) in aqueous solution. DHPS clusters were evident as spotty domains. STM enabled us to distinguish DHPS molecules from DHPC molecules depending on their electronic structures. The signal of the DHPS domains was abolished by neutralization with Ca(2+). The addition of the PS + Ca(2+)-binding protein of annexin V to the Ca(2+)-treated monolayer gave a number of spots corresponding to a single annexin V molecule.

Recent Progress in DIB Research: Survey of PAHS and DIBS

NASA Technical Reports Server (NTRS)

Salama, Farid; Galazutdinov, G.; Krelowski, J.; Biennier, L.; Beletsky, Y.; Song, I.

2013-01-01

The spectra of several neutral and ionized PAHs isolated in the gas phase at low temperature have been measured in the laboratory under experimental conditions that mimic interstellar conditions and are compared with an extensive set of astronomical spectra of reddened, early type stars [1, 2]. The comparisons of astronomical and laboratory data provide upper limits for the abundances of specific neutral PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations alone. We present the characteristics of the laboratory facility (COSmIC) that was developed for this study and discuss the findings resulting from the comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations. COSmIC combines a supersonic free jet expansion with discharge plasma and high-sensitivity cavity ringdown spectroscopy and provides experimental conditions that closely mimic the interstellar conditions. The column densities of the individual neutral PAH molecules and ions probed in these surveys are derived from the comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations. The comparisons of astronomical and laboratory data lead to clear and unambiguous conclusions regarding the expected abundances for PAHs of various sizes and charge states in the interstellar environments probed in the surveys. Band profile comparisons between laboratory and astronomical spectra lead to information regarding the molecular structures and characteristics associated with the DIB carriers in the corresponding lines-of-sight. These quantitative surveys of neutral and ionized PAHs in the optical range open the way for unambiguous quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments.

Mechanical Reliability of the Epoxy Sn-58wt.%Bi Solder Joints with Different Surface Finishes Under Thermal Shock

NASA Astrophysics Data System (ADS)

Sung, Yong-Gue; Myung, Woo-Ram; Jeong, Haksan; Ko, Min-Kwan; Moon, Jeonghoon; Jung, Seung-Boo

2018-04-01

The effect of thermal shock on the mechanical reliability of epoxy Sn-58wt.%Bi composite (epoxy Sn-58wt.%Bi) solder joints was investigated with different surface-finished substrates. Sn-58wt.%Bi-based solder has been considered as a promising candidate for low-temperature solder among various lead-free solders. However, Sn-58wt.%Bi solder joints can be easily broken under impact conditions such as mechanical shock, drop tests, and bending tests because of their poor ductility. Therefore, previous researchers have tried to improve the mechanical property of Sn-58wt.%Bi solder by additional elements and mixtures of metal powder and epoxy resin. Epoxy Sn-58wt.%Bi solder paste was fabricated by mixing epoxy resin and Sn-58wt.%Bi solder powder to enhance the mechanical reliability of Sn-58wt.%Bi solder joints. The epoxy Sn-58wt.%Bi solder paste was screen-printed onto various printed circuit board surfaces finished with organic solder preservatives (OSP), electroless nickel immersion gold (ENIG), and electroless nickel electroless palladium immersion gold (ENEPIG). The test components were prepared by a reflow process at a peak temperature of 190°C. The thermal shock test was carried out under the temperature range of - 40 to 125°C to evaluate the reliability of Sn-58wt.%Bi and epoxy Sn-58wt.%Bi solder joints. The OSP-finished sample showed a relatively higher mechanical property than those of ENIG and ENEPIG after thermal shock. The average number of cycles for epoxy Sn-58wt.%Bi solder with the OSP surface finish were 6 times higher than that for Sn-58wt.%Bi solder with the same finish. The microstructures of the solder joints were investigated by scanning electron microscopy, and the composition of the intermetallic compound (IMC) layer was analyzed by using energy dispersive spectrometry. Cu6Sn5 IMC was formed by the reaction between Sn-58wt.%Bi solder and a OSP surface-finished Cu after the reflow process. Ni3Sn4 IMC and (Ni, Pd)3Sn4 IMC were formed at the solder joints between the ENIG and solder, and between ENEPIG surface finish and solders, respectively.

Mechanical Reliability of the Epoxy Sn-58wt.%Bi Solder Joints with Different Surface Finishes Under Thermal Shock

NASA Astrophysics Data System (ADS)

Sung, Yong-Gue; Myung, Woo-Ram; Jeong, Haksan; Ko, Min-Kwan; Moon, Jeonghoon; Jung, Seung-Boo

2018-07-01

The effect of thermal shock on the mechanical reliability of epoxy Sn-58wt.%Bi composite (epoxy Sn-58wt.%Bi) solder joints was investigated with different surface-finished substrates. Sn-58wt.%Bi-based solder has been considered as a promising candidate for low-temperature solder among various lead-free solders. However, Sn-58wt.%Bi solder joints can be easily broken under impact conditions such as mechanical shock, drop tests, and bending tests because of their poor ductility. Therefore, previous researchers have tried to improve the mechanical property of Sn-58wt.%Bi solder by additional elements and mixtures of metal powder and epoxy resin. Epoxy Sn-58wt.%Bi solder paste was fabricated by mixing epoxy resin and Sn-58wt.%Bi solder powder to enhance the mechanical reliability of Sn-58wt.%Bi solder joints. The epoxy Sn-58wt.%Bi solder paste was screen-printed onto various printed circuit board surfaces finished with organic solder preservatives (OSP), electroless nickel immersion gold (ENIG), and electroless nickel electroless palladium immersion gold (ENEPIG). The test components were prepared by a reflow process at a peak temperature of 190°C. The thermal shock test was carried out under the temperature range of - 40 to 125°C to evaluate the reliability of Sn-58wt.%Bi and epoxy Sn-58wt.%Bi solder joints. The OSP-finished sample showed a relatively higher mechanical property than those of ENIG and ENEPIG after thermal shock. The average number of cycles for epoxy Sn-58wt.%Bi solder with the OSP surface finish were 6 times higher than that for Sn-58wt.%Bi solder with the same finish. The microstructures of the solder joints were investigated by scanning electron microscopy, and the composition of the intermetallic compound (IMC) layer was analyzed by using energy dispersive spectrometry. Cu6Sn5 IMC was formed by the reaction between Sn-58wt.%Bi solder and a OSP surface-finished Cu after the reflow process. Ni3Sn4 IMC and (Ni, Pd)3Sn4 IMC were formed at the solder joints between the ENIG and solder, and between ENEPIG surface finish and solders, respectively.

Effects of Sn Addition on the Microstructures and Mechanical Properties of Mg-6Zn-3Cu- xSn Magnesium Alloys

NASA Astrophysics Data System (ADS)

Zhang, Tao; Shen, Jun; Sang, Jia-Xin; Li, Yang; He, Pei-Pei

2015-08-01

In this paper, Mg-6Zn-3Cu- xSn (ZC63- xSn) magnesium alloys with different Sn contents (0, 1, 2, 4 wt pct) were fabricated and subjected to different heat treatments. The microstructures and mechanical properties of the obtained ZC63- xSn samples were investigated by optical microscopy, X-ray diffraction, scanning electron microscopy, Vickers hardness testing, and tensile testing. It was found that the As-cast Mg-6Zn-3Cu (ZC63) magnesium alloy mainly contained α-Mg grains and Mg(Zn,Cu) particles. Sn dissolved in α-Mg grains when Sn content was below 2 wt pct while Mg2Sn phase forms in the case of Sn content was above 4 wt pct. Addition of Sn refined both α-Mg grains and Mg(Zn,Cu) particles, and increased the volume fraction of Mg(Zn,Cu) particles. Compared with the Sn-free alloy, the microhardness of Sn-containing alloys increased greatly and that of As-extrude ZC63-4Sn sample achieved the highest value. The strength of ZC63 magnesium alloy was significantly enhanced because of Sn addition, which was attributed to grain refinement strengthening, solid solution strengthening, and precipitation strengthening. Furthermore, the ultimate yield stress, yield strength, and elongation of ZC63- xSn magnesium alloys were increased owing to the deceasing grain size induced by extrusion process.

Electron exchange between tin impurity U{sup –} centers in PbS{sub z}Se{sub 1–z} alloys

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

Marchenko, A. V.; Terukov, E. I.; Seregin, P. P., E-mail: ppseregin@mail.ru

2016-07-15

Using emission {sup 119mm}Sn({sup 119m}Sn) and {sup 119}Sb({sup 119m}Sn) Mössbauer spectroscopy, it is shown that impurity tin atoms in PbS{sub z}Se{sub 1–z} alloys substitute lead atoms and are two-electron donors with negative correlation energy (U{sup –} centers). It is found that the energy levels related to impurity tin atoms are in the lower half of the band gap at z ≥ 0.5 against the background of allowed valence-band states at z ≤ 0.4. The electron exchange between neutral and doubly ionized tin U{sup –} centers in partially compensated Pb{sub 0.99}Sn{sub 0.005}Na{sub 0.005}S{sub z}Se{sub 1–z} alloys is studied. The activation energymore » of this process decreases from 0.111(5) eV for a composition with z = 1 to 0.049(5) eV for compositions with c ≤ 0. For all z, the exchange is implemented via the simultaneous transfer of two electrons using delocalized valence-band states.« less

Serologic response of pups to the low-passage, modified-live canine parvovirus-2 component in a combination vaccine.

PubMed

O'Brien, S E

1994-04-15

Thirty pups from a general pet population were vaccinated for canine parvovirus-2 (CPV-2), using a low-passage, modified-live CPV-2 in a combination vaccine, every 3 weeks until the pups were between 11 and 18 weeks old. Canine parvovirus-2 antibody titers were measured by means of serum neutralization (SN) immediately before each vaccination and > or = 2 weeks after final vaccination. Thirteen pups that were initially seronegative (SN titer < 2 for CPV-2) developed protective titers (SN titer > or = 16) after 1 to 3 doses of the vaccine, administered when the pups were between 8 and 17 weeks old; 11 of the 13 developed protective titers after the first dose. Seventeen pups were initially seropositive for CPV-2 (SN titer > or = 2). Of these, 8 initially had titers < 16 and 3 others had titers that fell to < 16 during the study. Nine (82%) of these 11 pups developed protective titers. Results indicated that pups at high risk for CPV-2 disease should be vaccinated until 18 to 20 weeks old, even when the low-passage vaccine is used. Pups at lower risk of CPV-2 disease should be vaccinated periodically until 16 weeks old.

Microstructural Modification of Sn-0.7Cu Solder Alloys by Fe/Bi-Addition for Achieving High Mechanical Performance

NASA Astrophysics Data System (ADS)

Ali, Bakhtiar; Sabri, Mohd Faizul Mohd; Said, Suhana Mohd; Mahdavifard, Mohammad Hossein; Sukiman, Nazatul Liana; Jauhari, Iswadi

2017-08-01

In this work, we studied the Fe/Bi-bearing tin-copper (Sn-0.7Cu) solders for their microstructural and mechanical properties. The microstructure was studied using field emission scanning electron microscopy (FESEM) with a backscattered electron (BSE) detector, x-ray diffraction (XRD) analysis, and energy-dispersive x-ray spectroscopy (EDX). The microstructure study showed that Fe forms very few FeSn2 intermetallic compounds (IMCs) and does not significantly alter the microstructure of Sn-0.7Cu, whereas Bi controls the size of inter-dendritic regions containing Cu6Sn5 and Ag3Sn IMCs of the alloy, as well as significantly refines its primary β-Sn dendrites. Moreover, Bi atoms dissolve in β-Sn matrix, which in turn strengthen the solder by the Bi solid solution strengthening mechanism. Such microstructural modification leads to significant improvements in various mechanical properties of the alloy, including shear strength, impact toughness, and hardness values. Shear tests were performed with a 0.25 mm/min shear speed. The results showed that shear strength improves from 16.57 MPa to 38.36 MPa with the addition of Fe/Bi to Sn-0.7Cu, raising by about 130%. The energy absorbed during impact tests was measured for samples with the help of a Charpy impact testing machine with a 5.4 m/s impact speed. The results revealed that the addition of Fe/Bi to Sn-0.7Cu improves its impact absorbed energy by over 35%, increasing it from 7.5 J to 10.3 J. Vickers hardness tests were carried out for the test samples with a 245.2 mN applied load and 10 s dwell time. The results showed that the hardness number improves from 9.89 to 24.13 with Fe/Bi to Sn-0.7Cu, increasing by about 140%.

The relationship between clinical and standardized tests for hand-arm vibration syndrome.

PubMed

Poole, C J M; Mason, H; Harding, A-H

2016-06-01

Standardized laboratory tests are undertaken to assist the diagnosis and staging of hand-arm vibration syndrome (HAVS), but the strength of the relationship between the tests and clinical stages of HAVS is unknown. To assess the relationship between the results of thermal aesthesiometry (TA), vibrotactile (VT) thresholds and cold provocation (CP) tests with the modified Stockholm scales for HAVS and to determine whether the relationship is affected by finger skin temperature. Consecutive records of workers referred to a Tier 5 HAVS assessment centre from 2006 to 2015 were identified. The diagnosis and staging of cases was undertaken from the clinical information contained in the records. Cases with alternative or mixed diagnoses were excluded and staging performed according to the modified Stockholm scale without knowledge of the results of the standardized laboratory tests. A total of 279 cases of HAVS were analysed. Although there was a significant trend for sensorineural (SN) and vascular scores to increase with clinical stage (P < 0.01), there was no significant difference in scores between 2SN early and 2SN late or between 2SN late and 3SN. There was moderate correlation between the TA and VT scores and the clinical SN stages (r = 0.6). This correlation did not change when subjects were divided into those with a finger skin temperature <30 and >30°C. CP scores distributed bimodally and correlated poorly with clinical staging (r = 0.2). Standardized SN tests distinguish between the lower Stockholm stages, but not above 2SN early. This has implications for health surveillance and UK policy. © Crown copyright 2016.

The coelomic fluid of the sea urchin Tripneustes depressus shows antiviral activity against Suid herpesvirus type 1 (SHV-1) and rabies virus (RV).

PubMed

Salas-Rojas, M; Galvez-Romero, G; Anton-Palma, B; Acevedo, R; Blanco-Favela, F; Aguilar-Setién, A

2014-01-01

Several studies have reported that molecules extracted from invertebrates have activity against different viruses, even against those that do not infect these organisms in their environment. One of the main mechanisms against pathogens in these organisms is the production of antimicrobial peptides. The objective of this study was to determine whether the coelomic fluid (CF) of the sea urchin Tripneustes depressus has activity against Suid herpesvirus type 1 (SHV-1) and/or rabies virus (RV). We tested the antiviral activity of CF in neutralizing assays and observed 50% inhibition against SHV-1 lytic plaque formation using 33 μg of CF, whereas 21 μg CF was sufficient to obtain more than 90% inhibition for RV. Cytotoxicity to MDBK and BHK-21 cells was found with whole CF yet was eliminated by heating at 56 or 72 °C (even when using 50 μg of heat-inactivated CF supernatant [SN or thermostable fraction]), and SN retained the antiviral effect. In both cases, the antiviral effect was direct and thermostable (SN 56 and 72 °C), and the best inhibition was observed when CF + virus was incubated prior to the addition of the cells. Therefore, the coelomic fluid of T. depressus has antiviral activity against SHV-1 and RV that is direct and stable at 72 °C. We suggest that further assays should be performed using more accurate methods to characterize new molecules with antiviral activity that may result in new drugs. Copyright © 2013 Elsevier Ltd. All rights reserved.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: METSAT (S/N 108) AMSU-A1 Receiver Assemblies, P/N 1356429-1 S/N F05 and P/N 1356409-1 S/N F05

NASA Technical Reports Server (NTRS)

Haigh, R.; Krimchansky, S. (Technical Monitor)

2000-01-01

This is the Performance Verification Report, METSAT (S/N 108) AMSU-A1 Receiver Assemblies P/N 1356429-1 S/N F05 and P/N 1356409-1 S/N F05, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The ATP for the AMSU-A Receiver Subsystem, AE-26002/6A, is prepared to describe in detail the configuration of the test setups and the procedures of the tests to verify that the receiver subsystem meets the specifications as required either in the AMSU-A Instrument Performance and Operation Specifications, S-480-80, or in AMSU-A Receiver Subsystem Specifications, AE-26608, derived by the Aerojet System Engineering. Test results that verify the conformance to the specifications demonstrate the acceptability of that particular receiver subsystem.

The Reliability of Microalloyed Sn-Ag-Cu Solder Interconnections Under Cyclic Thermal and Mechanical Shock Loading

NASA Astrophysics Data System (ADS)

Mattila, Toni T.; Hokka, Jussi; Paulasto-Kröckel, Mervi

2014-11-01

In this study, the performance of three microalloyed Sn-Ag-Cu solder interconnection compositions (Sn-3.1Ag-0.52Cu, Sn-3.0Ag-0.52Cu-0.24Bi, and Sn-1.1Ag-0.52Cu-0.1Ni) was compared under mechanical shock loading (JESD22-B111 standard) and cyclic thermal loading (40 ± 125°C, 42 min cycle) conditions. In the drop tests, the component boards with the low-silver nickel-containing composition (Sn-Ag-Cu-Ni) showed the highest average number of drops-to-failure, while those with the bismuth-containing alloy (Sn-Ag-Cu-Bi) showed the lowest. Results of the thermal cycling tests showed that boards with Sn-Ag-Cu-Bi interconnections performed the best, while those with Sn-Ag-Cu-Ni performed the worst. Sn-Ag-Cu was placed in the middle in both tests. In this paper, we demonstrate that solder strength is an essential reliability factor and that higher strength can be beneficial for thermal cycling reliability but detrimental to drop reliability. We discuss these findings from the perspective of the microstructures and mechanical properties of the three solder interconnection compositions and, based on a comprehensive literature review, investigate how the differences in the solder compositions influence the mechanical properties of the interconnections and discuss how the differences are reflected in the failure mechanisms under both loading conditions.

Improved durability of proton exchange membrane fuel cells by introducing Sn (IV) oxide into electrodes using an ion exchange method

NASA Astrophysics Data System (ADS)

Poulsen, M. G.; Larsen, M. J.; Andersen, S. M.

2017-03-01

Electrodes of Proton Exchange Membrane Fuel Cells (PEMFCs), consisting of catalyst-coated gas diffusion layers, were subjected to an optimized ion exchange procedure, in which tin (IV) oxide (SnO2) nanoparticles were introduced into them. Both methanol and sulfuric acid were tested as ion exchange solvents. SnO2 has previously been shown to exhibit radical scavenging abilities towards radicals inside the electrocatalyst layers. Its presence inside the electrodes was confirmed using X-ray photoelectron spectroscopy and X-ray fluorescence. After exposure to an accelerated stress test in a three-electrode setup, the electrodes containing SnO2 were found to have retained approximately 73.0% of their original Pt, while only 53.2% was retained in electrodes treated identically, but without Sn. Similarly, the SnO2-treated electrodes also experienced a smaller loss in electrochemical surface area in comparison to before the accelerated stress test. A membrane electrode assembly (MEA) constructed with a SnO2-containing anode was evaluated over 500 h. The results showed remarkably reduced OCV decay rate and end of test hydrogen crossover compared to the control MEA, indicating that SnO2 aids in impeding membrane thinning and pinhole formation. The results point toward a positive effect of SnO2 on fuel cell durability, by reducing the degradation of the membrane as well as of the ionomer in the electrocatalyst layer.

Wafer-Level Hermetic Package by Low-Temperature Cu/Sn TLP Bonding with Optimized Sn Thickness

NASA Astrophysics Data System (ADS)

Wu, Zijian; Cai, Jian; Wang, Qian; Wang, Junqiang; Wang, Dejun

2017-10-01

In this paper, a wafer-level package with hermetic sealing by low-temperature Cu/Sn transient liquid phase (TLP) bonding for a micro-electromechanical system was introduced. A Cu bump with a Sn cap and sealing ring were fabricated simultaneously by electroplating. The model of Cu/Sn TLP bonding was established and the thicknesses of Cu and Sn were optimized after a series of bonding experiments. Cu/Sn wafer-level bonding was undertaken at 260°C for 30 min under a vacuum condition. An average shear strength of 50.36 MPa and a fine leak rate of 1.9 × 10-8 atm cc/s were achieved. Scanning electron microscope photos of the Cu/Sn/Cu interlayers were presented, and energy dispersive x-ray analysis was conducted simultaneously. The results showed that the Sn was completely consumed to form the stable intermetallic compound Cu3Sn. An aging test of 200 h at 200°C was conducted to test the performance of the hermetic sealing, while the results of shear strength, fine leak rate and bonding interface were also set out.

The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MegaSaura). I. The Sample and the Spectra

NASA Astrophysics Data System (ADS)

Rigby, J. R.; Bayliss, M. B.; Sharon, K.; Gladders, M. D.; Chisholm, J.; Dahle, H.; Johnson, T.; Paterno-Mahler, R.; Wuyts, E.; Kelson, D. D.

2018-03-01

We introduce Project MEGaSaURA: the Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas. MEGaSaURA comprises medium-resolution, rest-frame ultraviolet spectroscopy of N = 15 bright gravitationally lensed galaxies at redshifts of 1.68 < z < 3.6, obtained with the MagE spectrograph on the Magellan telescopes. The spectra cover the observed-frame wavelength range 3200 < λ o < 8280 Å the average spectral resolving power is R = 3300. The median spectrum has a signal-to-noise ratio (S/N) = 21 per resolution element at 5000 Å. As such, the MEGaSaURA spectra have superior S/N and wavelength coverage compared to what COS/HST provides for starburst galaxies in the local universe. This paper describes the sample, the observations, and the data reduction. We compare the measured redshifts for the stars, the ionized gas as traced by nebular lines, and the neutral gas as traced by absorption lines; we find the expected bulk outflow of the neutral gas, and no systemic offset between the redshifts measured from nebular lines and the redshifts measured from the stellar continuum. We provide the MEGaSaURA spectra to the astronomical community through a data release.

Editor's Highlight: Effects of Intraperitoneal Injection of SnS2 Flowers on Mouse Testicle.

PubMed

Bai, Disi; Li, Qingzhao; Xiong, Yanjie; Zhao, Junjian; Bai, Liyuan; Shen, Peijun; Yuan, Lu; Wu, Ping

2018-02-01

SnS2 nanoflowers (SnS2 NFs) have been widely used in photoelectric and catalytic applications. However, its explosure and reproductive toxicity is unknown. The aim of this study was to investigate the effect of exposure to 3 different sized-SnS2 flowers (dose: 38 mg/kg; size: 50, 80, and 200 nm) in testes of mice for 4 weeks by intraperitoneal injection. Though the body weight of mice treated or not with SnS2 NFs was not different, and SnS2 NFs were distributed to the organs including liver, kidney, spleen, heart, brain, and testis, more distribution SnS2 NFs (50 and 80 nm) were found in testicle tissues compared with SnS2 flowers (200 nm) in those tissues. The results of sperm count and survival analysis, histopathological evaluation, and qRT-PCR detection showed that there was moderate reproductive toxicity induced by the small-sized SnS2 NFs in testicle tissues. Furthermore, elevated malondialdehyde level and decreased superoxide dismutase activity were also observed in the SnS2 NFs (dose: 38 mg/kg; size: 50 and 80 nm) treated groups. Likewise, the qRT-PCR data indicated that SnS2 NFs can induce apoptosis and inflammation responses. Although the pro-inflammation marker of TNF-α, IL-1β, iNOS, and COX-2 at the mRNA levels were higher expression in 50 and 80 nm groups than that in control and 200 nm group, no statistical significance existed between 50 and 80 nm groups. Accordingly, the repeated-dose toxicity of SnS2 NFs in testicle tissues was also observed in a dose-dependent manner by intraperitoneal injection of SnS2 NFs (size: 50 nm; 0.38, 3.8, and 38 mg/kg) for 4 weeks, when determined by sperm count, survival rate, and qRT-PCR analysis. In addition, transmission electron microscopy showed that the ultrastructural abnormalities formed by the small-sized SnS2 NFs in testes were more severe than those formed by the large-sized SnS2 in testes. Taken together, these findings implied that the SnS2 NFs activated inflammation responses that signified apoptosis in murine testes. This study provided useful information for risk analysis and regulation of SnS2 NFs by administration agencies. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Electrochemical properties of free-standing Sn/SnO2/multi-walled carbon nano tube anode papers for Li-ion batteries

NASA Astrophysics Data System (ADS)

Alaf, M.; Gultekin, D.; Akbulut, H.

2013-06-01

Free-standing multiwalled carbon nano tube papers (buckypapers) were prepared by vacuum filtration from functionalized multi walled carbon nano tubes (MWCNTs) with controlling porosity. Double phase matrix Sn/SnO2/MWCNT nanocomposites were obtained in two steps, including thermal evaporation of metallic tin (Sn) on the MWCNT papers and RF plasma oxidation. The ratio between metallic tin (Sn) and tin oxide (SnO2) was controlled with plasma oxidation time. It was determined that the evaporated pure tin nano crystals were mechanically penetrated into pores of buckypapers to form functionally gradient nanocomposites. Sn/SnO2 coated on MWCNT buckypapers were used as working electrodes in assembled as coin-type (CR2016) test cells. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine the structure and morphology of the obtained nanocomposites. In addition, the discharge/charge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out to characterize the electrochemical properties of these composites as anode materials for Li-ion batteries.

Electric double layer at metal oxide surfaces:static properties of the cassiterite-water interface.

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

Vlcek, L.; Zhang, Z.; Machesky, M .L.

2007-03-24

The structure of water at the (110) surface of cassiterite ({alpha}-SnO{sub 2}) at ambient conditions was studied by means of molecular dynamics simulations and X-ray crystal truncation rod experiments and interpreted with the help of the revised MUSIC model of surface protonation. The interactions of the metal oxide in the simulations were described by a recently developed classical force field based on the SPC/E model of water. Two extreme cases of completely hydroxylated and nonhydroxylated surfaces were considered along with a mixed surface with 50% dissociation. To study the dependence of the surface properties on pH, neutral and negatively chargedmore » variants of the surfaces were constructed. Axial and lateral density distributions of water for different types of surfaces were compared to each other and to experimental axial density distributions found by X-ray experiments. Although significant differences were found between the structures of the studied interfaces, the axial distances between Sn and O atoms are very similar and therefore could not be clearly distinguished by the diffraction technique. The explanation of structures observed in the density distributions was provided by a detailed analysis of hydrogen bonding in the interfacial region. It revealed qualitatively different hydrating patterns formed at neutral hydroxylated and nonhydroxylated surfaces and suggested a preference for the dissociative adsorption of water. At negatively charged surfaces, however, the situation can be reversed by the electric field stabilizing a hydrogen bond network similar to that found at the neutral nonhydroxylated surface. Comparison with previously studied rutile ({alpha}-TiO{sub 2}) surfaces provided insight into the differences between the hydration of these two metal oxides, and an important role was ascribed to their different lattice parameters. A link to macroscopic properties was provided by the revised MUSIC surface protonation model. Explicit use of the Sn-O bond lengths based on ab initio calculations and H-bond configurations as inputs led to the prediction of a pH of zero net-proton induced surface charge (pH{sub pzc}) that agrees very well with those determined experimentally (about 4.4 at 298 K).« less

Electric double layer at metal oxide surfaces: Static properties of the cassiterite - Water Interface

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

Vlcek, Lukas; Zhang, Zhan; Machesky, Michael L.

2007-01-01

The structure of water at the (110) surface of cassiterite ({alpha}-SnO{sub 2}) at ambient conditions was studied by means of molecular dynamics simulations and X-ray crystal truncation rod experiments and interpreted with the help of the revised MUSIC model of surface protonation. The interactions of the metal oxide in the simulations were described by a recently developed classical force field based on the SPC/E model of water. Two extreme cases of completely hydroxylated and nonhydroxylated surfaces were considered along with a mixed surface with 50% dissociation. To study the dependence of the surface properties on pH, neutral and negatively chargedmore » variants of the surfaces were constructed. Axial and lateral density distributions of water for different types of surfaces were compared to each other and to experimental axial density distributions found by X-ray experiments. Although significant differences were found between the structures of the studied interfaces, the axial distances between Sn and O atoms are very similar and therefore could not be clearly distinguished by the diffraction technique. The explanation of structures observed in the density distributions was provided by a detailed analysis of hydrogen bonding in the interfacial region. It revealed qualitatively different hydrating patterns formed at neutral hydroxylated and nonhydroxylated surfaces and suggested a preference for the dissociative adsorption of water. At negatively charged surfaces, however, the situation can be reversed by the electric field stabilizing a hydrogen bond network similar to that found at the neutral nonhydroxylated surface. Comparison with previously studied rutile ({alpha}-TiO{sub 2}) surfaces provided insight into the differences between the hydration of these two metal oxides, and an important role was ascribed to their different lattice parameters. A link to macroscopic properties was provided by the revised MUSIC surface protonation model. Explicit use of the Sn-O bond lengths based on ab initio calculations and H-bond configurations as inputs led to the prediction of a pH of zero net-proton induced surface charge (pH{sub pzc}) that agrees very well with those determined experimentally (about 4.4 at 298 K).« less

Stabilization of Fermi level via electronic excitation in Sn doped CdO thin films

NASA Astrophysics Data System (ADS)

Das, Arkaprava; Singh, Fouran

2018-04-01

Pure and Sn doped CdO sol-gel derived thin films were deposited on corning glass substrate and further irradiated by swift heavy ion (SHI) (Ag and O) with fluence upto 3×1013 ions/cm2. The observed tensile stress from X-ray diffraction pattern at higher fluence for Ag ions can be corroborated to the imbrications of cylindrical tracks due to multiple impacts. The anomalous band gap enhancement after irradiation may be attributed to the consolidated effect of Burstein-Moss shift (BMS) and impurity induced virtual gap states (ViGs). At higher excitation density as Fermi stabilization level (EFS) tends to coincide with charge neutrality level (CNL), band gap enhancement saturates as further creation of additional defects inside the lattice becomes unsustainable. Raman spectroscopy divulges an intensity enhancement of 478 cm-1 LO phonon mode with Sn doping and irradiation induces further asymmetric peak broadening due to damage and disordering inside the lattice. However for 3% Sn doped thin film irradiated with Ag ions having 3×1013 fluence shows a drastic change in structural properties and reduction in band gap which might be attributed to the generation of localized energy levels between conduction and valance band due to high density of defects.

A solar-thermal energy harvesting scheme: enhanced heat capacity of molten HITEC salt mixed with Sn/SiOx core-shell nanoparticles

NASA Astrophysics Data System (ADS)

Lai, Chih-Chung; Chang, Wen-Chih; Hu, Wen-Liang; Wang, Zhiming M.; Lu, Ming-Chang; Chueh, Yu-Lun

2014-04-01

We demonstrated enhanced solar-thermal storage by releasing the latent heat of Sn/SiOx core-shell nanoparticles (NPs) embedded in a eutectic salt. The microstructures and chemical compositions of Sn/SiOx core-shell NPs were characterized. In situ heating XRD provides dynamic crystalline information about the Sn/SiOx core-shell NPs during cyclic heating processes. The latent heat of ~29 J g-1 for Sn/SiOx core-shell NPs was measured, and 30% enhanced heat capacity was achieved from 1.57 to 2.03 J g-1 K-1 for the HITEC solar salt without and with, respectively, a mixture of 5% Sn/SiOx core-shell NPs. In addition, an endurance cycle test was performed to prove a stable operation in practical applications. The approach provides a method to enhance energy storage in solar-thermal power plants.We demonstrated enhanced solar-thermal storage by releasing the latent heat of Sn/SiOx core-shell nanoparticles (NPs) embedded in a eutectic salt. The microstructures and chemical compositions of Sn/SiOx core-shell NPs were characterized. In situ heating XRD provides dynamic crystalline information about the Sn/SiOx core-shell NPs during cyclic heating processes. The latent heat of ~29 J g-1 for Sn/SiOx core-shell NPs was measured, and 30% enhanced heat capacity was achieved from 1.57 to 2.03 J g-1 K-1 for the HITEC solar salt without and with, respectively, a mixture of 5% Sn/SiOx core-shell NPs. In addition, an endurance cycle test was performed to prove a stable operation in practical applications. The approach provides a method to enhance energy storage in solar-thermal power plants. Electronic supplementary information (ESI) available: Detailed experimental results are included for the following: SEM images of the HITEC molten salt with and without a mixture of Sn/SiOx core-shell NPs; statistical diameter distribution of pure Sn and Sn/SiOx core-shell NPs; the HAADF image and EDS linescan profile of a Sn/SiOx core-shell NP; XRD analysis for Sn NPs annealing at different heating temperatures; the XRD spectra of Sn/SiOx core-shell NPs before and after RTA for the shell protection test. See DOI: 10.1039/c3nr06810b

A new trivalent SnSAG surface antigen chimera for efficient detection of antibodies against Sarcocystis neurona and diagnosis of equine protozoal myeloencephalitis.

PubMed

Yeargan, Michelle; de Assis Rocha, Izabela; Morrow, Jennifer; Graves, Amy; Reed, Stephen M; Howe, Daniel K

2015-05-01

Enzyme-linked immunosorbent assays (ELISAs) based on the SnSAG surface antigens of Sarcocystis neurona provide reliable detection of infection by the parasite. Moreover, accurate serodiagnosis of equine protozoal myeloencephalitis (EPM) is achieved with the SnSAG ELISAs by measuring antibodies in serum and cerebrospinal fluid (CSF) to reveal active infection in the central nervous system. Two independent ELISAs based on recombinant (r)SnSAG2 or a chimeric fusion of SnSAG3 and SnSAG4 (rSnSAG4/3) are currently used together for EPM serodiagnosis to overcome varied antibody responses in different horses. To achieve reliable antibody detection with a single ELISA instead of 2 separate ELISAs, rSnSAG2 was fused with rSnSAG4/3 into a single trivalent protein, designated rSnSAG2/4/3. Paired serum and CSF from 163 horses were tested with all 3 ELISAs. When the consensus antibody titers obtained with the rSnSAG2 and rSnSAG4/3 ELISAs were compared to the single SAG2/4/3 ELISA titers, Spearman rank correlation coefficients of ρ = 0.74 and ρ = 0.90 were obtained for serum and CSF, respectively, indicating strong agreement between the tests. When the rSnSAG2 and rSnSAG4/3 consensus serum-to-CSF titer ratio was compared to the rSnSAG2/4/3 serum-to-CSF titer ratio, the Spearman correlation coefficient was ρ = 0.87, again signifying strong agreement. Importantly, comparing the diagnostic interpretation of the serum-to-CSF titer ratios yielded a Cohen kappa value of 0.77. These findings suggest that the single ELISA based on the trivalent rSnSAG2/4/3 will provide serologic and diagnostic results that are highly comparable to the consensus of the 2 independent ELISAs based on rSnSAG2 and rSnSAG4/3. © 2015 The Author(s).

Structure, mechanical property and corrosion behaviors of (HA+β-TCP)/Mg-5Sn composite with interpenetrating networks.

PubMed

Wang, X; Li, J T; Xie, M Y; Qu, L J; Zhang, P; Li, X L

2015-11-01

In this paper, a novel (Hydroxyapatite+β-tricalcium phosphate)/Mg-5Sn ((HA+β-TCP)/Mg-5Sn) composite with interpenetrating networks was fabricated by infiltrating Mg-5Sn alloy into porous HA+β-TCP using suction casting technique. The structure, mechanical property and corrosion behaviors of the composite have been evaluated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical testing, electrochemical and immersion test. It is shown that the molten Mg-5Sn alloy has infiltrated not only into the pores but also into the struts of the HA+β-TCP scaffold to forming a compact composite. The microstructure observation also shows that the Mg alloy contacts to the HA+β-TCP closely, and no reaction layer can be found between Mg-5Sn alloy and scaffold. The ultimate compressive strength of the composite is as high as 176MPa, which is about four fifths of the strength of the Mg-5Sn bulk alloy. The electrochemical and immersion tests indicate that the corrosion resistance of the composite is better than that of the Mg-5Sn bulk alloy. The corrosion products on the composite surface are mainly Mg(OH)2, Ca3(PO4)2 and HA. Appropriate mechanical and corrosion properties of the (HA+β-TCP)/Mg-5Sn composite indicate its possibility for new bone tissue implant materials. Copyright © 2015 Elsevier B.V. All rights reserved.

Thiourea derivatives as chelating agents for bioconjugation of rhenium and technetium.

PubMed

Gomez, J D Castillo; Hagenbach, A; Gerling-Driessen, U I M; Koksch, B; Beindorff, N; Brenner, W; Abram, U

2017-10-31

Potential tetradentate thiocarbamoylbenzamidine derivatives H 4 L have been synthesized from the corresponding benzimidoyl chlorides and triglycine. They are suitable chelating agents for the oxidotechnetium(v) and oxidorhenium(v) cores and form stable, neutral [MO(HL)] complexes with an equatorial SN 3 coordination sphere and an additional, uncoordinated carboxylic group, which can be used for bioconjugation. Representatives of the rhenium and 99 Tc products have been isolated and analyzed with spectroscopic methods and X-ray diffraction. Bioconjugates of these complexes with angiotensin-II have been synthesized and structurally characterized. Analogous 99m Tc complexes have been produced and tested in vitro and in vivo. The experiments confirm a considerable stability for the [ 99m Tc(HL)] product as well as for its bioconjugate and recommend this class of compounds for further bioconjugation studies towards clinical applications.

Synthesis and Electrochemical Properties of Amorphous Carbon Coated Sn Anode Material for Lithium Ion Batteries and Sodium Ion Batteries.

PubMed

Choi, Ji-Seub; Lee, Hoi-Jin; Ha, Jong-Keun; Cho, Kwon-Koo

2018-09-01

Sn is one of the promising anode material for lithium-ion and sodium-ion batteries because of Sn has many advantages such as a high theoretical capacity of 994 mAh/g, inexpensive, abundant and nontoxic. However, Sn-based anodes have a critical problem from pulverization of the particles due to large volume change (>300% in lithium-ion battery and 420% in the sodium-ion battery) during alloying/dealloying reaction. To overcome this problem, we fabricate Sn/C particle of core/shell structure. Sn powder was produced by pulsed wire explosion in liquid media, and amorphous carbon coating process was prepared by hydrothermal synthesis. The charge capacity of Sn electrode and amorphous carbon coated Sn electrode was 413 mAh/g and 452 mAh/g after 40 cycles in lithium half-cell test. The charge capacity of Sn electrode and amorphous carbon coated Sn electrode was 240 mAh/g and 487 mAh/g after 40 cycles in sodium half-cell test. Amorphous carbon coating contributed to the improvement of capacity in lithium and sodium battery systems. And the effect of amorphous carbon coating in sodium battery system was superior to that in lithium battery system.

Abundances of Neutral and Ionized PAH Along The Lines-of-Sight of Diffuse and Translucent Interstellar Clouds

NASA Astrophysics Data System (ADS)

Salama, Farid; Galazutdinov, G.; Krelowski, J.; Biennier, L.; Beletsky, Y.; Song, I.

2013-06-01

The spectra of neutral and ionized PAHs isolated in the gas phase at low temperature have been measured in the laboratory under conditions that mimic interstellar conditions and are compared with a set of astronomical spectra of reddened, early type stars. The comparisons of astronomical and laboratory data provide upper limits for the abundances of neutral PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations. We present the characteristics of the laboratory facility (COSmIC) that was developed for this study and discuss the findings resulting from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. COSmIC combines a supersonic jet expansion with discharge plasma and cavity ringdown spectroscopy and provides experimental conditions that closely mimic the interstellar conditions. The column densities of the individual PAH molecules and ions probed in these surveys are derived from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. The comparisons of astronomical and laboratory data lead to clear conclusions regarding the expected abundances for PAHs in the interstellar environments probed in the surveys. Band profile comparisons between laboratory and astronomical spectra lead to information regarding the molecular structures and characteristics associated with the DIB carriers in the corresponding lines-of-sight. These quantitative surveys of neutral and ionized PAHs in the optical range open the way for quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments. Acknowledgements: F.S. acknowledges the support of the Astrophysics Research and Analysis Program of the NASA Space Mission Directorate and the technical support provided by R. Walker at NASA ARC. J.K. acknowledges the financial support of the Polish State. The authors are deeply grateful to the ESO archive as well as to the ESO staff members for their active support.

ROTARY FUEL INJECTION PUMP WEAR TESTING USING A 30 %/ 70% ATJ/F-24 FUEL BLEND

DTIC Science & Technology

2017-09-30

30/70 ATJ/F-24 with 24-ppm CI/LI Fuel at 77 ºC ............................................... 49 Figure 28. Pump SN:17200043 Transfer Pump Blade ...Pump SN:17200043 Transfer Pump Blade Edges with 1000-Hours Testing with 30/70 ATJ/F-24 with 24-ppm CI/LI Fuel at 77 ºC...50 Figure 30. Pump SN:17200043 Transfer Pump Blade Sides before Testing with 30/70 ATJ/F-24 with 24-ppm CI/LI Fuel at 77 ºC

Aspects of nonviral gene therapy: correlation of molecular parameters with lipoplex structure and transfection efficacy in pyridinium-based cationic lipids.

PubMed

Parvizi, Paria; Jubeli, Emile; Raju, Liji; Khalique, Nada Abdul; Almeer, Ahmed; Allam, Hebatalla; Manaa, Maryem Al; Larsen, Helge; Nicholson, David; Pungente, Michael D; Fyles, Thomas M

2014-01-30

This study seeks correlations between the molecular structures of cationic and neutral lipids, the lipid phase behavior of the mixed-lipid lipoplexes they form with plasmid DNA, and the transfection efficacy of the lipoplexes. Synthetic cationic pyridinium lipids were co-formulated (1:1) with the cationic lipid 1,2-dimyristoyl-sn-glycero-3-ethylphosphocholine (EPC), and these lipids were co-formulated (3:2) with the neutral lipids 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) or cholesterol. All lipoplex formulations exhibited plasmid DNA binding and a level of protection from DNase I degradation. Composition-dependent transfection (beta-galactosidase and GFP) and cytotoxicity was observed in Chinese hamster ovarian-K1 cells. The most active formulations containing the pyridinium lipids were less cytotoxic but of comparable activity to a Lipofectamine 2000™ control. Molecular structure parameters and partition coefficients were calculated for all lipids using fragment additive methods. The derived shape parameter values correctly correlated with observed hexagonal lipid phase behavior of lipoplexes as derived from small-angle X-ray scattering experiments. A transfection index applicable to hexagonal phase lipoplexes derived from calculated parameters of the lipid mixture (partition coefficient, shape parameter, lipoplex packing) produced a direct correlation with transfection efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.

Tribal love: the neural correlates of passionate engagement in football fans.

PubMed

Duarte, Isabel C; Afonso, Sónia; Jorge, Helena; Cayolla, Ricardo; Ferreira, Carlos; Castelo-Branco, Miguel

2017-05-01

The tribal character of the affective link between football fans and their teams is a well-recognized phenomenon. Other forms of love such as romantic or maternal attachment have previously been studied from a neuroimaging point of view. Here we aimed to investigate the neural basis of this tribal form of love, which implies both the feeling of belongingness and rivalry against opposing teams. A pool of 56 participants was submitted to an fMRI experimental design involving the presentation of winning and losing football moments of their loved, rival or neutral teams. We found recruitment of amygdala and reward regions, including the ventral tegmental area (VTA) and substantia nigra (SN), as well as other limbic regions involved in emotional cognition, for 'positive vs neutral' and 'positive vs negative' conditions. The latter contrast was correlated with neuropsychological scores of fanaticism in the amygdala and regions within the reward system, as the VTA and SN. The observation of increased response patterns in critical components of the reward system, in particular for positive content related to the loved team, suggests that this kind of non-romantic love reflects a specific arousal and motivational state, which is biased for emotional learning of positive outcomes. © The Author (2017). Published by Oxford University Press.

Metabolic incorporation of unsaturated fatty acids into boar spermatozoa lipids and de novo formation of diacylglycerols.

PubMed

Svetlichnyy, Valentin; Müller, Peter; Pomorski, Thomas G; Schulze, Martin; Schiller, Jürgen; Müller, Karin

2014-01-01

Lipids play an important role in the maturation, viability and function of sperm cells. In this study, we examined the neutral and polar lipid composition of boar spermatozoa by thin-layer chromatography/mass spectrometry. Main representatives of the neutral lipid classes were diacylglycerols containing saturated (myristoyl, palmitoyl and stearoyl) fatty acyl residues. Glycerophosphatidylcholine and glycerophosphatidylethanolamine with alk(en)yl ether residues in the sn-1 position and unsaturated long chained fatty acyl residues in sn-2 position were identified as the most prominent polar lipids. The only glycoglycerolipid was sulfogalactosylglycerolipid carrying 16:0-alkyl- and 16:0-acyl chains. Using stable isotope-labelling, the metabolic incorporation of exogenously supplied fatty acids was analysed. Boar spermatozoa incorporated hexadecenoic (16:1), octadecenoic (18:1), octadecadienoic (18:2) and octadecatrienoic (18:3) acids primarily in the diacylglycerols and glycerophosphatidylcholines. In contrast, incorporation of eicosapentaenoic acid (20:5) was not detected. The analysis of molecular species composition subsequent to the incorporation of exogenous [(14)C]-octadecadienoic acid suggests two pathways for incorporation of exogenous fatty acids into glycerophosphatidylcholine: (1) de novo synthesis of glycerophosphatidylcholine via the CDP-choline pathway and (2) reacylation of lysophosphatidylcholine via an acyltransferase. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Differentiation of urinary calculi with dual energy CT: effect of spectral shaping by high energy tin filtration.

PubMed

Thomas, Christoph; Krauss, Bernhard; Ketelsen, Dominik; Tsiflikas, Ilias; Reimann, Anja; Werner, Matthias; Schilling, David; Hennenlotter, Jörg; Claussen, Claus D; Schlemmer, Heinz-Peter; Heuschmid, Martin

2010-07-01

In dual energy (DE) computed tomography (CT), spectral shaping by additional filtration of the high energy spectrum can theoretically improve dual energy contrast. The aim of this in vitro study was to examine the influence of an additional tin filter for the differentiation of human urinary calculi by dual energy CT. A total of 36 pure human urinary calculi (uric acid, cystine, calciumoxalate monohydrate, calciumoxalate dihydrate, carbonatapatite, brushite, average diameter 10.5 mm) were placed in a phantom and imaged with 2 dual source CT scanners. One scanner was equipped with an additional tin (Sn) filter. Different combinations of tube voltages (140/80 kV, 140/100 kV, Sn140/100 kV, Sn140/80 kV, with Sn140 referring to 140 kV with the tin filter) were applied. Tube currents were adapted to yield comparable dose indices. Low- and high energy images were reconstructed. The calculi were segmented semiautomatically in the datasets and DE ratios (attenuation@low_kV/attenuation@high_kV) and were calculated for each calculus. DE contrasts (DE-ratio_material1/DE-ratio_material2) were computed for uric acid, cystine and calcified calculi and compared between the combinations of tube voltages. Using exclusively DE ratios, all uric acid, cystine and calcified calculi (as a group) could be differentiated in all protocols; the calcified calculi could not be differentiated among each other in any examination protocol. The highest DE ratios and DE contrasts were measured for the Sn140/80 protocol (53%-62% higher DE contrast than in the 140/80 kV protocol without additional filtration). The DE ratios and DE contrasts of the 80/140 kV and 100/Sn140 kV protocols were comparable. Uric acid, cystine and calcified calculi could be reliably differentiated by any of the protocols. A dose-neutral gain of DE contrast was found in the Sn-filter protocols, which might improve the differentiation of smaller calculi (Sn140/80 kV) and improve image quality and calculi differentiation in larger patients (Sn140/100 kV). However, even with the improved spectral separation of the Sn-filter protocols, the DE ratios of calcified calculi are not sufficiently distinct to allow a differentiation within this group.

Limits of visual communication: the effect of signal-to-noise ratio on the intelligibility of American Sign Language.

PubMed

Pavel, M; Sperling, G; Riedl, T; Vanderbeek, A

1987-12-01

To determine the limits of human observers' ability to identify visually presented American Sign Language (ASL), the contrast s and the amount of additive noise n in dynamic ASL images were varied independently. Contrast was tested over a 4:1 range; the rms signal-to-noise ratios (s/n) investigated were s/n = 1/4, 1/2, 1, and infinity (which is used to designate the original, uncontaminated images). Fourteen deaf subjects were tested with an intelligibility test composed of 85 isolated ASL signs, each 2-3 sec in length. For these ASL signs (64 x 96 pixels, 30 frames/sec), subjects' performance asymptotes between s/n = 0.5 and 1.0; further increases in s/n do not improve intelligibility. Intelligibility was found to depend only on s/n and not on contrast. A formulation in terms of logistic functions was proposed to derive intelligibility of ASL signs from s/n, sign familiarity, and sign difficulty. Familiarity (ignorance) is represented by additive signal-correlated noise; it represents the likelihood of a subject's knowing a particular ASL sign, and it adds to s/n. Difficulty is represented by a multiplicative difficulty coefficient; it represents the perceptual vulnerability of an ASL sign to noise and it adds to log(s/n).

Improved detection of equine antibodies against Sarcocystis neurona using polyvalent ELISAs based on the parasite SnSAG surface antigens.

PubMed

Yeargan, Michelle R; Howe, Daniel K

2011-02-28

Equine protozoal myeloencephalitis (EPM) is a common neurologic disease of horses that is caused by the apicomplexan pathogen Sarcocystis neurona. To help improve serologic diagnosis of S. neurona infection, we have modified existing enzyme-linked immunosorbent assays (ELISAs) based on the immunogenic parasite surface antigens SnSAG2, SnSAG3, and SnSAG4 to make the assays polyvalent, thereby circumventing difficulties associated with parasite antigenic variants and diversity in equine immune responses. Two approaches were utilized to achieve polyvalence: (1) mixtures of the individual recombinant SnSAGs (rSnSAGs) were included in single ELISAs; (2) a collection of unique SnSAG chimeras that fused protein domains from different SnSAG surface antigens into a single recombinant protein were generated for use in the ELISAs. These new assays were assessed using a defined sample set of equine sera and cerebrospinal fluids (CSFs) that had been characterized by Western blot and/or were from confirmed EPM horses. While all of the polyvalent ELISAs performed relatively well, the highest sensitivity and specificity (100%/100%) were achieved with assays containing the rSnSAG4/2 chimera (Domain 1 of SnSAG4 fused to SnSAG2) or using a mixture of rSnSAG3 and rSnSAG4. The rSnSAG4 antigen alone and the rSnSAG4/3 chimera (Domain 1 of SnSAG4 fused to Domain 2 of SnSAG3) exhibited the next best accuracy at 95.2% sensitivity and 100% specificity. Binding ratios and percent positivity (PP) ratios, determined by comparing the mean values for positive versus negative samples, showed that the most advantageous signal to noise ratios were provided by rSnSAG4 and the rSnSAG4/3 chimera. Collectively, our results imply that a polyvalent ELISA based on SnSAG4 and SnSAG3, whether as a cocktail of two proteins or as a single chimeric protein, can give optimal results in serologic testing of serum or CSF for the presence of antibodies against S. neurona. The use of polyvalent SnSAG ELISAs will enhance the reliability of serologic testing for S. neurona infection, which should lead to improved diagnosis of EPM. Copyright © 2010 Elsevier B.V. All rights reserved.

Silver colloidal nanoparticles: effect on matrix composition and structure of Candida albicans and Candida glabrata biofilms.

PubMed

Monteiro, D R; Silva, S; Negri, M; Gorup, L F; de Camargo, E R; Oliveira, R; Barbosa, D B; Henriques, M

2013-04-01

The aim of this study was to assess the effect of different silver nanoparticles (SN) concentrations on the matrix composition and structure of Candida albicans and Candida glabrata biofilms. Candida biofilms were developed in 6-well microtiter plates during 48 h. After, these biofilms were exposed to 13.5 or 54 μg SN ml(-1) for 24 h. Then, extracellular matrices were extracted from biofilms and analysed chemically in terms of proteins, carbohydrates and DNA. To investigate the biofilm structure, scanning electron microscopy (SEM) and epifluorescence microscopy were used. SN interfered with the matrix composition of Candida biofilms tested in terms of protein, carbohydrate and DNA, except for the protein content of C. albicans biofilm. By SEM, Candida biofilms treated with SN revealed structural differences, when compared with the control groups. Further, SN showed a trend of agglomeration within the biofilms. Epifluorescence microscopy images suggest that SN induced damage on cell walls of the Candida isolates tested. In general, irrespective of concentration, SN affected the matrix composition and structure of Candida biofilms and these findings may be related to the mechanisms of biocide action of SN. This study reveals new insights about the behaviour of SN when in contact with Candida biofilms. SN may contribute to the development of therapies to prevent or control Candida infections. © 2012 The Society for Applied Microbiology.

Cu6Sn5 Whiskers Precipitated in Sn3.0Ag0.5Cu/Cu Interconnection in Concentrator Silicon Solar Cells Solder Layer

PubMed Central

Zhang, Liang; Liu, Zhi-quan; Yang, Fan; Zhong, Su-juan

2017-01-01

Cu6Sn5 whiskers precipitated in Sn3.0Ag0.5Cu/Cu interconnection in concentrator silicon solar cells solder layer were found and investigated after reflow soldering and during aging. Ag3Sn fibers can be observed around Cu6Sn5 whiskers in the matrix microstructure, which can play an active effect on the reliability of interconnection. Different morphologies of Cu6Sn5 whiskers can be observed, and hexagonal rod structure is the main morphology of Cu6Sn5 whiskers. A hollow structure can be observed in hexagonal Cu6Sn5 whiskers, and a screw dislocation mechanism was used to represent the Cu6Sn5 growth. Based on mechanical property testing and finite element simulation, Cu6Sn5 whiskers were regarded as having a negative effect on the durability of Sn3.0Ag0.5Cu/Cu interconnection in concentrator silicon solar cells solder layer. PMID:28772686

Hot-dipped tin-zinc on U-0. 75 w/o Ti

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

Weirick, L.J.

1979-09-01

Conventional Zn galvanizing of U-0.75 Ti results in nonuniform coatings and reduced elongation because of thermal aging of the surface of the U-Ti. A lower melting material which would give sacrificial galvanic protection to the U-Ti was found in the Sn-Zn alloy system. The present work describes: (1) the metallography of the Sn-Zn system, (2) the electrochemistry of the Sn-Zn system with respect to U-Ti, (3) the mechanics of applying a Sn-Zn coating to U-Ti, (4) salt spray corrosion test results of various Sn-Zn alloys applied to U-Ti coupons, and (5) mechanical property tests of coated U-Ti tensile bars. Anmore » 80 Sn-20 Zn alloy (MP-280/sup 0/C) was chosen for the galvanizing study because of its lower melting point. The results showed that all alloys of the Sn-Zn system galvanically protected the U-Ti in salt fog environments. The lack of a suitable low temperature flux prevented the operation of the Sn-Zn bath at its optimum temperature and low elongations were obtained with this coating system.« less

Surface characterization of tin-based inorganic EUV resists

NASA Astrophysics Data System (ADS)

Frederick, Ryan T.; Diulus, J. Trey; Lyubinetsky, Igor; Hutchison, Danielle C.; Olsen, Morgan R.; Nyman, May; Herman, Gregory S.

2018-03-01

Metal oxide nanomaterials have shown promise for use as EUV resists. Recently, significant efforts have focused on tinoxo clusters that have high absorption coefficient Sn centers and radiation sensitive organic ligands. In our studies, we have investigated a β-Keggin butyl-Sn cluster (β-NaSn13), which is charge-neutral and allows studying radiation induced chemistries without interference from counterions. We have used ambient pressure X-ray photoelectron spectroscopy (APXPS) to investigate the contrast properties of the β-NaSn13 in ultrahigh vacuum (UHV) and in the presence of ambient oxygen. These contrast studies indicate that ambient oxygen reduces the dose requirements for the solubility transition of the β-NaSn13 photoresists. APXPS spectra collected before and after the solubility transition shows that ambient oxygen causes a greater loss of butyl ligands from the samples and the formation of more tin oxide for larger doses, suggesting the presence of reactive oxygen species. APXPS was also used to study processes during the post exposure bake, where we compared the differences in film chemistries in ambient oxygen or in UHV. There were only very small differences in the APXPS spectra before exposure and after exposure and the post exposure bake. However, ambient oxygen resulted in some changes for unexposed regions during the post exposure bake; there was a greater ratio of tin oxide to other oxygen species (alkoxy ligands, hydroxyls) for samples annealed in oxygen. These results have significance for EUV and e-beam lithography processing parameters, as well as implications for cluster design and ligand chemistries.

Does a network structure exist in molecular liquid SnI4 and GeI4?

NASA Astrophysics Data System (ADS)

Sakagami, Takahiro; Fuchizaki, Kazuhiro

2017-04-01

The existence of a network structure consisting of electrically neutral tetrahedral molecules in liquid SnI4 and GeI4 at ambient pressure was examined. The liquid structures employed for the examination were obtained from a reverse Monte Carlo analysis. The structures were physically interpreted by introducing an appropriate intermolecular interaction. A ‘bond’ was then defined as an intermolecular connection that minimizes the energy of intermolecular interaction. However, their ‘bond’ energy is too weak for the ‘bond’ and the resulting network structure to be defined statically. The vertex-to-edge orientation between the nearest molecules is so ubiquitous that almost all of the molecules in the system can take part in the network, which is reflected in the appearance of a prepeak in the structure factor.

Report on the Acceptance Test of the CRI Y-MP 8128, 10 February - 12 March 1990

NASA Technical Reports Server (NTRS)

Carter, Russell; Kutler, Paul (Technical Monitor)

1998-01-01

The NAS Numerical Aerodynamic Simulation Facility's HSP 2 computer system, a CRI Y-MP 832 SN #1002, underwent a major hardware upgrade in February of 1990. The 32 MWord, 6.3 ns mainframe component of the system was replaced with a 128 MWord, 6.0 ns CRI Y-MP 8128 mainframe, SN #1030. A 30 day Acceptance Test of the computer system was performed by the NAS RND HSP group from 08:00 February 10, 1990 to 08:00 March 12, 1990. Overall responsibility for the RND HSP Acceptance Test was assumed by Duane Carbon. The terms of the contract required that the SN #1030 achieve an effectiveness level of greater than or equal to ninety (90) percent for 30 consecutive days within a 60 day time frame. After the first thirty days, the effectiveness level of SN #1030 was 94.4 percent, hence the acceptance test was passed.

Strains of Sarcocystis neurona exhibit differences in their surface antigens, including the absence of the major surface antigen SnSAG1.

PubMed

Howe, Daniel K; Gaji, Rajshekhar Y; Marsh, Antoinette E; Patil, Bhagyashree A; Saville, William J; Lindsay, David S; Dubey, J P; Granstrom, David E

2008-05-01

A gene family of surface antigens is expressed by merozoites of Sarcocystis neurona, the primary cause of equine protozoal myeloencephalitis (EPM). These surface proteins, designated SnSAGs, are immunodominant and therefore excellent candidates for development of EPM diagnostics or vaccines. Prior work had identified an EPM isolate lacking the major surface antigen SnSAG1, thus suggesting there may be some diversity in the SnSAGs expressed by different S. neurona isolates. Therefore, a bioinformatic, molecular and immunological study was conducted to assess conservation of the SnSAGs. Examination of an expressed sequence tag (EST) database revealed several notable SnSAG polymorphisms. In particular, the EST information implied that the EPM strain SN4 lacked the major surface antigen SnSAG1. The absence of this surface antigen from the SN4 strain was confirmed by both Western blot and Southern blot. To evaluate SnSAG polymorphisms in the S. neurona population, 14 strains were examined by Western blots using monospecific polyclonal antibodies against the four described SnSAGs. The results of these analyses demonstrated that SnSAG2, SnSAG3, and SnSAG4 are present in all 14 S. neurona strains tested, although some variance in SnSAG4 was observed. Importantly, SnSAG1 was not detected in seven of the strains, which included isolates from four cases of EPM and a case of fatal meningoencephalitis in a sea otter. Genetic analyses by PCR using gene-specific primers confirmed the absence of the SnSAG1 locus in six of these seven strains. Collectively, the data indicated that there is heterogeneity in the surface antigen composition of different S. neurona isolates, which is an important consideration for development of serological tests and prospective vaccines for EPM. Furthermore, the diversity reported herein likely extends to other phenotypes, such as strain virulence, and may have implications for the phylogeny of the various Sarcocystis spp. that undergo sexual stages of their life cycle in opossums.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: AMSU-A1 METSAT Instrument (S/N 105) Qualification, Level Vibration Tests of December 1998 (S/O 605445, OC-419)

NASA Technical Reports Server (NTRS)

Heffner, R. J.

1998-01-01

This is the Engineering Test Report, AMSU-AL METSAT Instrument (S/N 105) Qualification Level Vibration Tests of December 1998 (S/0 605445, OC-419), for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109

NASA Technical Reports Server (NTRS)

Valdez, A.

2000-01-01

This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

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

Tang, Chunying; Lu, Jialin; Han, Jingyu

Polymeric lanthanide complexes with thiostannate and polyamine mixed ligands, [Ln(peha)(μ–SnS{sub 4}H)]{sub n} [Ln=La (1a), Nd (1b)] and [(Ln(tepa)(μ–OH)){sub 2}(μ–Sn{sub 2}S{sub 6})]{sub n}nH{sub 2}O [Ln=Nd (2a), Sm (2b), Gd (2c), Dy (2d)] (peha=pentaethylenehexamine, tepa=tetraethylenepentamine) were respectively prepared in peha and tepa coordinative solvents by the solvothermal methods. In 1a and 1b, the Ln{sup 3+} ions are coordinated by a hexadentate peha ligand forming [Ln(peha)]{sup 3+} units. The [SnS{sub 4}H]{sup 3−} anion chelates a [Ln(peha)]{sup 3+} unit via two S atoms and coordinates to another [Ln(peha)]{sup 3+} unit via the third S atom. As a result, the [Ln(peha)]{sup 3+} units are connectedmore » into coordination polymers [Ln(peha)(μ–SnS{sub 4}H)]{sub n} by an unprecedented tridentate μ–η{sup 1},η{sup 2}–SnS{sub 4}H bridging ligands. In 2a–2d, the Ln{sup 3+} ions are coordinated by a pentadentate tepa ligand, and two [Ln(tepa)]{sup 3+} units are joined by two μ–OH bridges to form a binuclear [(Ln(tepa)(μ–OH)){sub 2}]{sup 4+} unit. Behaving as a bidentate μ–η{sup 1}, η{sup 1}–Sn{sub 2}S{sub 6} bridging ligand, the Sn{sub 2}S{sub 6} unit connects [(Ln(tepa)(μ–OH)){sub 2}]{sup 4+} units into a neutral coordination polymer [(Ln(tepa)(μ–OH)){sub 2}(μ–Sn{sub 2}S{sub 6})]{sub n} via the trans S atoms. The Ln{sup 3+} ions are in distorted monocapped square antiprismatic and bicapped trigonal prismatic environments in [(Ln(peha)(μ–SnS{sub 4}H)]{sub n} and [(Ln(tepa)(μ–OH)){sub 2}(μ–Sn{sub 2}S{sub 6})]{sub n}, respectively. The denticities of ethylene polyamine play an important role on the formation and complexation of the thiostannate in the presence of lanthanide ions. Compounds 1a–2d show well-defined absorption edges with band gaps between 2.81 and 3.15 eV. - Graphical abstract: Lanthanide coordination polymers concerning thiostannate ligands were prepared by the solvothermal methods, and μ{sub 3}–SnS{sub 4}H and μ–Sn{sub 2}S{sub 6} ligands to Ln(III) centers were obtained. - Highlights: • Lanthanide coordination polymers were prepared in polyamines with higher denticity. • The μ–η{sup 1},η{sup 2}–SnS{sub 4}H and μ–η{sup 1},η{sup 1}–Sn{sub 2}S{sub 6} ligands to Ln(III) centers were obtained. • Effect of amine on the complexation of Ln(III) with thiostannate is observed.« less

Measuring the Properties of Dark Energy with Photometrically Classified Pan-STARRS Supernovae. I. Systematic Uncertainty from Core-collapse Supernova Contamination

NASA Astrophysics Data System (ADS)

Jones, D. O.; Scolnic, D. M.; Riess, A. G.; Kessler, R.; Rest, A.; Kirshner, R. P.; Berger, E.; Ortega, C. A.; Foley, R. J.; Chornock, R.; Challis, P. J.; Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Huber, M. E.; Kaiser, N.; Kudritzki, R.-P.; Metcalfe, N.; Wainscoat, R. J.; Waters, C.

2017-07-01

The Pan-STARRS (PS1) Medium Deep Survey discovered over 5000 likely supernovae (SNe) but obtained spectral classifications for just 10% of its SN candidates. We measured spectroscopic host galaxy redshifts for 3147 of these likely SNe and estimate that ˜1000 are Type Ia SNe (SNe Ia) with light-curve quality sufficient for a cosmological analysis. We use these data with simulations to determine the impact of core-collapse SN (CC SN) contamination on measurements of the dark energy equation of state parameter, w. Using the method of Bayesian Estimation Applied to Multiple Species (BEAMS), distances to SNe Ia and the contaminating CC SN distribution are simultaneously determined. We test light-curve-based SN classification priors for BEAMS as well as a new classification method that relies upon host galaxy spectra and the association of SN type with host type. By testing several SN classification methods and CC SN parameterizations on large SN simulations, we estimate that CC SN contamination gives a systematic error on w ({σ }w{CC}) of 0.014, 29% of the statistical uncertainty. Our best method gives {σ }w{CC}=0.004, just 8% of the statistical uncertainty, but could be affected by incomplete knowledge of the CC SN distribution. This method determines the SALT2 color and shape coefficients, α and β, with ˜3% bias. However, we find that some variants require α and β to be fixed to known values for BEAMS to yield accurate measurements of w. Finally, the inferred abundance of bright CC SNe in our sample is greater than expected based on measured CC SN rates and luminosity functions.

Characterization of heat-induced interaction of neutral liposome with lipid membrane of Streptomyces griseus cell.

PubMed

Ngo, Kien Xuan; Umakoshi, Hiroshi; Shimanouchi, Toshinori; Kuboi, Ryoichi

2009-10-15

The interaction between the neutral 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) liposomes and cell membrane of Streptomyces griseus induced by the heat treatment at specific temperature was investigated, focusing on the internalization of the neutral POPC liposomes with S. griseus cells. In an attempt to clarify the modes of liposome internalization, various kinds of inhibitors of endocytotic pathways were used to treat S. griseus cells. The efficiency of the heat treatment on liposome-cell membrane interactions was finally characterized based on the hydrophobic, electrostatic interactions and hydration effect. In fact, the internalization of the neutral liposomes into these cells was found to show higher rate and greater amount at higher temperatures. The kinetic study showed that the maximum amount of the internalized liposomes was, respectively, 469 x 10(5) and 643 x 10(5) liposomes/cell at 37 and 41 degrees C. The internalization of the neutral liposomes induced by the heat treatment was characterized, implying that the endocytosis occurred. The interactions involving the internalization, adsorption, and fusion of these liposomes with S. griseus cells were mainly contributed by the hydrophobic interaction and the unstable hydrogen bonds caused by the loss of water of surface hydration of cell membrane rather than the electrostatic interaction under the specific heat condition.

Substantia nigra hyperechogenicity is related to decline in verbal memory in healthy elderly adults.

PubMed

Yilmaz, R; Behnke, S; Liepelt-Scarfone, I; Roeben, B; Pausch, C; Runkel, A; Heinzel, S; Niebler, R; Suenkel, U; Eschweiler, G W; Maetzler, W; Berg, D

2016-05-01

Deficits in cognition have been reported in Parkinson's disease (PD) already in the early and even in the pre-motor stages. Whilst substantia nigra hyperechogenicity measured by transcranial B-mode sonography (TCS) represents a strong PD marker and is associated with an increased risk for PD in still healthy individuals, its association with cognitive performance in prodromal PD stages is not well established. Two different cohorts of healthy elderly individuals were assessed by TCS and two different neuropsychological test batteries covering executive functions, verbal memory, language, visuo-constructional function and attention. Cognitive performance was compared between individuals with hyperechogenicity (SN+) and without hyperechogenicity (SN-). In both cohorts, SN+ individuals performed significantly worse than the SN- group in tests assessing verbal memory (word list delayed recall P = 0.05, logical memory II P < 0.017). Significant differences in Mini-Mental State Examination score (cohort 1, P = 0.02) and executive function tests (cohort 2, Stroop Color-Word Reading, P = 0.004) could only be shown in one of the two cohorts. No between-group effects were found in other cognitive tests and domains. These results indicate that individuals with the PD risk marker SN+ perform worse in verbal memory compared to SN- independent of the assessment battery. Memory performance should be assessed in detail in individuals at risk for PD. © 2016 EAN.

Creep properties of Pb-free solder joints

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

Song, H.G.; Morris Jr., J.W.; Hua, F.

2002-04-01

Describes the creep behavior of three Sn-rich solders that have become candidates for use in Pb-free solder joints: Sn-3.5Ag, Sn-3Ag-0.5Cu and Sn-0.7Cu. The three solders show the same general behavior when tested in thin joints between Cu and Ni/Au metallized pads at temperatures between 60 and 130 C. Their steady-state creep rates are separated into two regimes with different stress exponents(n). The low-stress exponents range from {approx}3-6, while the high-stress exponents are anomalously high (7-12). Strikingly, the high-stress exponent has a strong temperature dependence near room temperature, increasing significantly as the temperature drops from 95 to 60 C. The anomalousmore » creep behavior of the solders appears to be due to the dominant Sn constituent. Joints of pure Sn have stress exponents, n, that change with stress and temperature almost exactly like those of the Sn-rich solder joints. Research on creep in bulk samples of pure Sn suggests that the anomalous temperature dependence of the stress exponent may show a change in the dominant mechanism of creep. Whatever its source, it has the consequence that conventional constitutive relations for steady-state creep must be used with caution in treating Sn-rich solder joints, and qualification tests that are intended to verify performance should be carefully designed.« less

Tin-Platinum catalysts interactions on titania and silica

NASA Astrophysics Data System (ADS)

Nava, N.; Del Angel, P.; Salmones, J.; Baggio-Saitovitch, E.; Santiago, P.

2007-09-01

Pt-Sn was supported on titania and silica, and the resulting interactions between the components in prepared samples and the resulting interactions between the components before and after treatment with hydrogen were characterized by Mössbauer spectroscopy, X-ray diffraction, Rietveld refinement, high-resolution transmission electron microscopy (HRTEM) and catalytic tests data. Results show the presence of Pt and SnO 2 after calcinations, and Pt 3Sn, PtSn and PtSn 3 after reduction. Rietveld analysis shows that some Ti 4+ are replaced by Sn 4+ atoms in the titania structure. Finally, HRTEM and the practically absence of activity observed confirms that metallic platinum is encapsulated.

Quench performance and field quality of FNAL twin-aperture 11 T Nb 3Sn dipole model for LHC upgrades

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

Stoynev, Stoyan; Andreev, Nikolai; Apollinari, Giorgio

A 2 m long single-aperture dipole demonstrator and two 1 m long single-aperture models based on Nb 3Sn superconductor have been built and tested at FNAL. The two 1 m long collared coils were then assembled in a twin-aperture Nb 3Sn dipole demonstrator compatible with the LHC main dipole and tested in two thermal cycles. This paper summarizes the quench performance of the FNAL twin-aperture Nb 3Sn 11 T dipole in the temperature range of 1.9-4.5 K. The results of magnetic measurements for one of the two apertures are also presented. Test results are compared to the performance of coilsmore » in a single-aperture configuration. Lastly, a summary of quench propagation studies in both apertures is given.« less

Quench performance and field quality of FNAL twin-aperture 11 T Nb 3Sn dipole model for LHC upgrades

DOE PAGES

Stoynev, Stoyan; Andreev, Nikolai; Apollinari, Giorgio; ...

2016-12-07

A 2 m long single-aperture dipole demonstrator and two 1 m long single-aperture models based on Nb 3Sn superconductor have been built and tested at FNAL. The two 1 m long collared coils were then assembled in a twin-aperture Nb 3Sn dipole demonstrator compatible with the LHC main dipole and tested in two thermal cycles. This paper summarizes the quench performance of the FNAL twin-aperture Nb 3Sn 11 T dipole in the temperature range of 1.9-4.5 K. The results of magnetic measurements for one of the two apertures are also presented. Test results are compared to the performance of coilsmore » in a single-aperture configuration. Lastly, a summary of quench propagation studies in both apertures is given.« less

Microstructural evolution and mechanical properties of SnAgCu alloys

NASA Astrophysics Data System (ADS)

Fouassier, O.; Heintz, J.-M.; Chazelas, J.; Geffroy, P.-M.; Silvain, J.-F.

2006-08-01

Lead containing solder paste is now considered as an environmental threat. In order to eliminate this undesirable environmental impact associated to their production, a family of lead-free solder joint, Sn-3.8Ag-0.7Cu, is proposed. Microstructural and mechanical data of this solder joint have been acquired and compared with the most common used SnPb solder paste. The evolution of the microstructure as well as the failure mode and the mechanical properties of SnAgCu solder joint are discussed as a function of strain rate, annealing treatments, and testing temperature. Tensile tests have been performed, at temperatures ranging from -50to+150°C, on bulk samples. Changes of the mechanical properties of bulk tested samples are actually correlated with microstructural changes, as shown by transmission electronic microscopy investigations.

ATM CMG bearing failure analysis

NASA Technical Reports Server (NTRS)

1975-01-01

The cause or causes for the failure of ATM CMG S/N 5 (Skylab 1) and the anomalies associated with ATM CMG S/N 6 (Skylab 2) were investigated. Skylab telemetry data were reviewed and presented in the form of parameter distributions. The theory that the problems were caused by marginal bearing lubrication was studied along with the effects of orbital conditions on lubricants. Bearing tests were performed to investigate the effect of lubricant or lack of lubricant in the ATM CMG bearings and the dispersion and migration of the lubricant. The vacuum and weightless conditions of space were simulated in the bearing tests. Analysis of the results of the tests conducted points to inadequate lubrication as the predominant factor causing the failure of ATM CMG S/N 5 (Skylab 1) and the anomalies associated with ATM CMG S/N 6 (Skylab 2).

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: AMSU-A2 METSAT Instrument (S/N 108) Acceptance Level Vibration Tests of Dec 1999/Jan 2000 (S/O 784077, OC-454)

NASA Technical Reports Server (NTRS)

Heffner, R.

2000-01-01

This is the Engineering Test Report, AMSU-A2 METSAT Instrument (S/N 108) Acceptance Level Vibration Test of Dec 1999/Jan 2000 (S/O 784077, OC-454), for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, 08

NASA Technical Reports Server (NTRS)

Valdez, A.

2000-01-01

This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

Serum antibody responses to vaccinal antigens in lean and obese geriatric dogs.

PubMed

Ellis, John; Gow, Sheryl; Rhodes, Carrie; Lacoste, Stacey; Kong, Lyndsay; Musil, Kristyna; Snead, Elisabeth

2016-05-01

The immune responses in control dogs [1 to 4 years of age, body condition score (BCS): 4 to 5 out of 9] were compared to those of aging dogs (based on breed and body size) either categorized as lean (BCS: 4 to 5 out of 9) or obese (BCS: 8 to 9 out of 9). Of interest were the serum titers to the following common agents found in vaccines, canine parainfluenza virus (CPIV), canine parvovirus (CPV), canine distemper virus (CDV), canine respiratory coronavirus (CRCoV), and Bordetella bronchiseptica. There were no statistical differences in the antibodies to CPIV, B. bronchispetica, and CRCoV, among the age/weight categories, nor among the age/weight categories and the time, in days, between the date of sample collection and the date of the last recorded vaccination for CPIV, B. bronchiseptica, CPV, and CDV. For CPV, the control dogs had significantly (P < 0.002) higher serum neutralization (SN) titers than the lean geriatric dogs and the obese geriatric dogs. For CDV SN titers, the only statistically significant (P = 0.01) difference was that the control dogs had higher SN titers than the lean geriatric dogs.

Rapid ionization of the environment of SN 1987A

NASA Technical Reports Server (NTRS)

Raga, A. C.

1987-01-01

It has been suggested by some authors that IUE observations of the supernova SN 1987A show the presence of a strong component of the interstellar C IV 1550 and Si IV 1393 absorption lines at a velocity that approximately corresponds to the velocity of the LMC. It is possible that this component might come from originally neutral (or at least not very highly ionized) gas which has been photoionized by the initially very strong ionizing radiation field of the supernova. Theoretical considerations of this scenario lead to the study of fast (with velocities of about c) ionization fronts. It is shown that for reasonable model parameters it is possible to obtain considerably large C IV column densities, in agreement with the IUE observations. On the other hand, the models do not so easily predict the large Si IV column densities that are also obtained from the IUE observations. It is found that only models in which the interstellar medium surrounding SN 1987A is initially composed of already ionized hydrogen and helium predict substantial Si IV column densities. This result provides an interesting prediction of the ionization state of the environment of the presupernova star.

Serum antibody responses to vaccinal antigens in lean and obese geriatric dogs

PubMed Central

Ellis, John; Gow, Sheryl; Rhodes, Carrie; Lacoste, Stacey; Kong, Lyndsay; Musil, Kristyna; Snead, Elisabeth

2016-01-01

The immune responses in control dogs [1 to 4 years of age, body condition score (BCS): 4 to 5 out of 9] were compared to those of aging dogs (based on breed and body size) either categorized as lean (BCS: 4 to 5 out of 9) or obese (BCS: 8 to 9 out of 9). Of interest were the serum titers to the following common agents found in vaccines, canine parainfluenza virus (CPIV), canine parvovirus (CPV), canine distemper virus (CDV), canine respiratory coronavirus (CRCoV), and Bordetella bronchiseptica. There were no statistical differences in the antibodies to CPIV, B. bronchispetica, and CRCoV, among the age/weight categories, nor among the age/weight categories and the time, in days, between the date of sample collection and the date of the last recorded vaccination for CPIV, B. bronchiseptica, CPV, and CDV. For CPV, the control dogs had significantly (P < 0.002) higher serum neutralization (SN) titers than the lean geriatric dogs and the obese geriatric dogs. For CDV SN titers, the only statistically significant (P = 0.01) difference was that the control dogs had higher SN titers than the lean geriatric dogs. PMID:27152043

GLAST/EAAT1-induced glutamine release via SNAT3 in Bergmann glial cells: evidence of a functional and physical coupling.

PubMed

Martínez-Lozada, Zila; Guillem, Alain M; Flores-Méndez, Marco; Hernández-Kelly, Luisa C; Vela, Carmelita; Meza, Enrique; Zepeda, Rossana C; Caba, Mario; Rodríguez, Angelina; Ortega, Arturo

2013-05-01

Glutamate, the major excitatory transmitter in the vertebrate brain, is removed from the synaptic cleft by a family of sodium-dependent glutamate transporters profusely expressed in glial cells. Once internalized, it is metabolized by glutamine synthetase to glutamine and released to the synaptic space through sodium-dependent neutral amino acid carriers of the N System (SNAT3/slc38a3/SN1, SNAT5/slc38a5/SN2). Glutamine is then taken up by neurons completing the so-called glutamate/glutamine shuttle. Despite of the fact that this coupling was described decades ago, it is only recently that the biochemical framework of this shuttle has begun to be elucidated. Using the established model of cultured cerebellar Bergmann glia cells, we sought to characterize the functional and physical coupling of glutamate uptake and glutamine release. A time-dependent Na⁺-dependent glutamate/aspartate transporter/EAAT1-induced System N-mediated glutamine release could be demonstrated. Furthermore, D-aspartate, a specific glutamate transporter ligand, was capable of enhancing the co-immunoprecipitation of Na⁺-dependent glutamate/aspartate transporter and Na⁺-dependent neutral amino acid transporter 3, whereas glutamine tended to reduce this association. Our results suggest that glial cells surrounding glutamatergic synapses may act as sensors of neuron-derived glutamate through their contribution to the neurotransmitter turnover. © 2013 International Society for Neurochemistry.

Effects of Surface Finishes and Current Stressing on Interfacial Reaction Characteristics of Sn-3.0Ag-0.5Cu Solder Bumps

NASA Astrophysics Data System (ADS)

Kim, Jae-Myeong; Jeong, Myeong-Hyeok; Yoo, Sehoon; Park, Young-Bae

2012-04-01

The effects of surface finishes on the in situ interfacial reaction characteristics of ball grid array (BGA) Sn-3.0Ag-0.5Cu lead-free solder bumps were investigated under annealing and electromigration (EM) test conditions of 130°C to 175°C with 5.0 × 103 A/cm2. During reflow and annealing, (Cu,Ni)6Sn5 intermetallic compound (IMC) formed at the interface of electroless nickel immersion gold (ENIG) finish. In the case of both immersion Sn and organic solderability preservative (OSP) finishes, Cu6Sn5 and Cu3Sn IMCs formed. Overall, the IMC growth velocity of ENIG was much lower than that of the other finishes. The activation energies of total IMCs were found to be 0.52 eV for ENIG, 0.78 eV for immersion Sn, and 0.72 eV for OSP. The ENIG finish appeared to present an effective diffusion barrier between the Cu substrate and the solder, which leads to better EM reliability in comparison with Cu-based pad systems. The failure mechanisms were explored in detail via in situ EM tests.

Thermomechanical behavior of tin-rich (lead-free) solders

NASA Astrophysics Data System (ADS)

Sidhu, Rajen Singh

In order to adequately characterize the behavior of ball-grid-array (BGA) Pb-free solder spheres in electronic devices, the microstructure and thermomechanical behavior need to be studied. Microstructure characterization of pure Sn, Sn-0.7Cu, Sn-3.5Ag, and Sn-3.9Ag-0.7Cu alloys was conducted using optical microscopy, scanning electron microscopy, transmission electron microscopy, image analysis, and a novel serial sectioning 3D reconstruction process. Microstructure-based finite-element method (FEM) modeling of deformation in Sn-3.5Ag alloy was conducted, and it will be shown that this technique is more accurate when compared to traditional unit cell models for simulating and understanding material behavior. The effect of cooling rate on microstructure and creep behavior of bulk Sn-rich solders was studied. The creep behavior was evaluated at 25, 95, and 120°C. Faster cooling rates were found to increase the creep strength of the solders due to refinement of the solder microstructure. The creep behavior of Sn-rich single solder spheres reflowed on Cu substrates was studied at 25, 60, 95, and 130°C. Testing was conducted using a microforce testing system, with lap-shear geometry samples. The solder joints displayed two distinct creep behaviors: (a) precipitation-strengthening (Sn-3.5Ag and Sn-3.9Ag-0.7Cu) and (b) power law creep accommodated by grain boundary sliding (GBS) (Sn and Sn-0.7Cu). The relationship between microstructural features (i.e. intermetallic particle size and spacing), stress exponents, threshold stress, and activation energies are discussed. The relationship between small-length scale creep behavior and bulk behavior is also addressed. To better understand the damage evolution in Sn-rich solder joints during thermal fatigue, the local damage will be correlated to the cyclic hysteresis behavior and crystal orientations present in the Sn phase of solder joints. FEM modeling will also be utilized to better understand the macroscopic and local strain response of the lap shear geometry.

Influence of Toothbrushing on the Antierosive Effect of Film-Forming Agents.

PubMed

Scaramucci, Taís; João-Souza, Samira Helena; Lippert, Frank; Eckert, George J; Aoki, Idalina V; Hara, Anderson T

2016-01-01

This study evaluated the influence of toothbrushing on the antierosive effect of solutions containing sodium fluoride (225 ppm/F), stannous chloride (800 ppm/Sn), sodium linear polyphosphate (2%/LPP), and their combinations, and deionized water as negative control (C). Solutions were tested in a 5-day erosion-remineralization-abrasion cycling model, using enamel and dentin specimens (n = 8). Erosion was performed 6 times/day for 5 min, exposure to the test solutions 3 times/day for 2min, and toothbrushing (or not) with toothpaste slurry 2 times/day for 2 min (45 strokes). Surface loss (SL) was determined by noncontact profilometry. Data were analyzed using three-way ANOVA (α = 0.05). Brushing caused more SL than no brushing for enamel (mean ± SD, in micrometers: 52.7 ± 6.6 and 33.0 ± 4.5, respectively), but not for dentin (28.2 ± 1.9 and 26.6 ± 1.8, respectively). For enamel without brushing, F+LPP+Sn showed the lowest SL (23.8 ± 3.4), followed by F+Sn (30.6 ± 4.9) and F+LPP (31.7 ± 1.7), which did not differ from each other. No differences were found between the other groups and C (37.8 ± 2.1). When brushing, F+LPP+Sn exhibited the lowest SL (36.7 ± 2.4), not differing from F+LPP (39.1 ± 1.8). F, F+Sn and LPP+Sn were similar (46.7 ± 2.9, 42.1 ± 2.8 and 45.3 ± 4.6, respectively) and better than C (52.7 ± 4.3). Sn (55.0 ± 2.4) and LPP (51.0 ± 4.3) did not differ from C. For dentin, neither groups differed from C, regardless of brushing. In conclusion, toothbrushing did not affect the antierosive effect of F+Sn, F+LPP and F+LPP+Sn on enamel, although overall it led to more erosion than nonbrushing. F and LPP+Sn showed a protective effect only under brushing conditions, whereas Sn and LPP did not exhibit any protection. For dentin, neither toothbrushing nor the test solutions influenced the development of erosion. © 2016 S. Karger AG, Basel.

Effect of a chitosan additive to a Sn2+-containing toothpaste on its anti-erosive/anti-abrasive efficacy--a controlled randomised in situ trial.

PubMed

Schlueter, N; Klimek, J; Ganss, C

2014-01-01

It is well known that Sn(2+) is a notable anti-erosive agent. There are indications that biopolymers such as chitosan can enhance the effect of Sn(2+), at least in vitro. However, little information exists about their anti-erosive/anti-abrasive in situ effects. In the present in situ study, the efficacy of Sn(2+)-containing toothpastes in the presence or absence of chitosan was tested. Ten subjects participated in the randomised crossover study, wearing mandibular appliances with human enamel specimens. Specimens were extraorally demineralised (7 days, 0.5% citric acid, pH 2.6; 6 × 2 min/day) and intraorally exposed to toothpaste suspensions (2 × 2 min/day). Within the suspension immersion time, one half of the specimens were additionally brushed intraorally with a powered toothbrush (5 s, 2.5 N). Tested preparations were a placebo toothpaste (negative control), two experimental toothpastes (F/Sn = 1,400 ppm F(-), 3,500 ppm Sn(2+); F/Sn/chitosan = 1,400 ppm F(-), 3,500 ppm Sn(2+), 0.5 % chitosan) and an SnF2-containing gel (positive control, GelKam = 3,000 ppm Sn(2+), 1,000 ppm F(-)). Substance loss was quantified profilometrically (μm). In the placebo group, tissue loss was 11.2 ± 4.6 (immersion in suspension) and 17.7 ± 4.7 (immersion in suspension + brushing). Immersion in each Sn(2+)-containing suspension significantly reduced tissue loss (p ≤ 0.01); after immersion in suspension + brushing, only the treatments with GelKam (5.4 ± 5.5) and with F/Sn/chitosan (9.6 ± 5.6) significantly reduced loss [both p ≤ 0.05 compared to placebo; F/Sn 12.8 ± 6.4 (not significant)] Chitosan enhanced the efficacy of the Sn(2+)-containing toothpaste as an anti-erosive/anti-abrasive agent. The use of Sn(2+)- and chitosan-containing toothpaste is a good option for symptomatic therapy in patients with regular acid impacts.

Kilowatt Isotope Power System: component test report for the Ground Demonstration System Alternator Stator

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

Brainard, E.L.

1978-04-25

Results are presented of acceptance tests conducted on the Alternator Stator, S/N 002, for the Kilowatt Isotope Power System. These results show that the Alternator Stator, S/N 002 for the Kilowatt Isotope Power System has satisfactorily completed the testing set forth within Sundstrand Test Specification 2538. Test requirements of TS 2538 were extracted from the Kilowatt Isotope Power System, and Phase I Test Plan.

Metallurgical characterization of experimental Ag-based soldering alloys.

PubMed

Ntasi, Argyro; Al Jabbari, Youssef S; Silikas, Nick; Al Taweel, Sara M; Zinelis, Spiros

2014-10-01

To characterize microstructure, hardness and thermal properties of experimental Ag-based soldering alloys for dental applications. Ag12Ga (AgGa) and Ag10Ga5Sn (AgGaSn) were fabricated by induction melting. Six samples were prepared for each alloy and microstructure, hardness and their melting range were determined by, scanning electron microscopy, energy dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD), Vickers hardness testing and differential scanning calorimetry (DSC). Both alloys demonstrated a gross dendritic microstructure while according to XRD results both materials consisted predominately of a Ag-rich face centered cubic phase The hardness of AgGa (61 ± 2) was statistically lower than that of AgGaSn (84 ± 2) while the alloys tested showed similar melting range of 627-762 °C for AgGa and 631-756 °C for AgGaSn. The experimental alloys tested demonstrated similar microstructures and melting ranges. Ga and Sn might be used as alternative to Cu and Zn to modify the selected properties of Ag based soldering alloys.

Metallurgical characterization of experimental Ag-based soldering alloys

PubMed Central

Ntasi, Argyro; Al Jabbari, Youssef S.; Silikas, Nick; Al Taweel, Sara M.; Zinelis, Spiros

2014-01-01

Aim To characterize microstructure, hardness and thermal properties of experimental Ag-based soldering alloys for dental applications. Materials and methods Ag12Ga (AgGa) and Ag10Ga5Sn (AgGaSn) were fabricated by induction melting. Six samples were prepared for each alloy and microstructure, hardness and their melting range were determined by, scanning electron microscopy, energy dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD), Vickers hardness testing and differential scanning calorimetry (DSC). Results Both alloys demonstrated a gross dendritic microstructure while according to XRD results both materials consisted predominately of a Ag-rich face centered cubic phase The hardness of AgGa (61 ± 2) was statistically lower than that of AgGaSn (84 ± 2) while the alloys tested showed similar melting range of 627–762 °C for AgGa and 631–756 °C for AgGaSn. Conclusion The experimental alloys tested demonstrated similar microstructures and melting ranges. Ga and Sn might be used as alternative to Cu and Zn to modify the selected properties of Ag based soldering alloys. PMID:25382945

Sensitivity of Nb$$_3$$Sn Rutherford-Type Cables to Transverse Pressure

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

Barzi, E.; Wokas, T.; Zlobin, A. V.

Fermilab is developing high field superconducting magnets for future accelerators based on Nb/sub 3/Sn strands. Testing the critical current of superconducting cables under compression is a means to appraise the performance of the produced magnet. However, these cable tests are expensive and labor-intensive. A fixture to assess the superconducting performance of a Nb/sub 3/Sn strand within a reacted and impregnated cable under pressure was designed and built at Fermilab. Several Rutherford-type cables were fabricated at Fermilab and at LBNL using multifilamentary Nb/sub 3/Sn strands. The sensitivity of Nb/sub 3/Sn to transverse pressure was measured for a number of Nb/sub 3/Snmore » technologies (Modified Jelly Roll, Powder-in-Tube, Internal Tin, and Restack Rod Process). Results on the effect of a stainless steel core in the cable are also shown.« less

Tetrylones: An Intriguing Class of Monoatomic Zero-valent Group 14 Compounds.

PubMed

Majhi, Paresh Kumar; Sasamori, Takahiro

2018-02-13

Tetrylones (ylidones) represent a class of zero-valent group 14 compounds with the general formula EL 2 (E=C, Si, Ge, Sn, or Pb; L=neutral σ-donating ligand), wherein the tetrel atom, E(0), possess its four valence electrons in the form of two electron lone pairs, and is moreover coordinated by two ligands (L) via donor-acceptor interactions (L→E←L). This review focuses on the synthesis, structure, reactivity, and computational examination of the isolable heavier tetrylones (Si, Ge, Sn) that have been discovered recently. A comprehensive review on carbone chemistry is beyond the scope of this review. It should also be noted that tetrylones contain two different types of lone pairs, that is, one that exhibits p-type and one that exhibits s-type characteristics. Different behavior should thus be expected when these lone pairs react with Lewis acids. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biomolecular Interactions of Tannin Isolated from Oenothera gigas with Liposomes.

PubMed

Sekowski, Szymon; Ionov, Maksim; Dubis, Alina; Mavlyanov, Saidmukhtar; Bryszewska, Maria; Zamaraeva, Maria

2016-04-01

We have examined the interaction between hydrolysable tannin 1-O-galloyl-4,6-hexahydroxydiphenoyl-β-D-glucose (OGβDG) with neutral liposomes as a model of cell membranes composed of three lipids: lecithin, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) at different mass ratios. OGβDG in the concentration range 0.5-15 µg/ml (0.4-12 µM) strongly interacts with liposomal membranes by changing their structure, surface charge and fluidity. Used OGβDG molecules decrease and increase the rigidity of hydrophilic surface and hydrophobic parts of liposomes, respectively. At higher concentrations of tannin (>15 µM), liposomes are aggregated. Fourier Transform Infra-Red (FTIR) analysis showed that mainly -OH groups from OGβDG and also PO(2-) groups from phospholipids are responsible for the interaction. Obtained data indicate the importance of membrane lipid composition in interactions between tannins and cells.

SN-38 loaded polymeric micelles to enhance cancer therapy

NASA Astrophysics Data System (ADS)

Gu, Quanrong; Xing, James Z.; Huang, Min; He, Chuan; Chen, Jie

2012-05-01

7-Ethyl-10-hydroxycamptothecin (SN-38) loaded poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (Pluronic F-108) and poly(ethylene glycol)-block-poly(ɛ-caprolactone) (PEG-b-PCL) nanoparticles were successfully prepared by a modified film hydration method and characterized by scanning electric microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and dynamic light scattering (DLS). Satisfactory drug loading of 20.73 ± 0.66% and a high encapsulation efficiency of 83.83 ± 1.32% were achieved. The SN-38 nanoparticles (SN-38 NPs) can completely disperse into a phosphate buffered saline (PBS) medium to produce a clear aqueous suspension that remains stable for up to three days. Total drug releases were 67.91% and 91.09% after 24 h in a PBS or fetal bovine serum (FBS) medium. Half maximal inhibitory concentration (IC50) tests of SN-38 and SN-38 NPs on A549 lung cells produced results of 200.0 ± 14.9 ng ml-1 and 80.0 ± 4.6 ng ml-1, respectively. Similarly, IC50 tests of SN-38 and SN-38 NPs on MCF-7 breast cells yielded results of 16.0 ± 0.7 ng ml-1 and 8.0 ± 0.5 ng ml-1, respectively. These in vitro IC50 studies show significant (p < 0.01) enhancement of the SN-38 NP drug efficiency in killing cancer cells in comparison to the free drug SN-38 control. All the materials used for this nanoformulation are approved by the US FDA, with the virtue of extremely low toxicity to normal cells.

Expression of the System N transporter (SNAT5/SN2) during development indicates its plausible role in glutamatergic neurotransmission.

PubMed

Rodríguez, Angelina; Ortega, Arturo; Berumen, Laura C; García-Alcocer, María G; Giménez, Cecilio; Zafra, Francisco

2014-07-01

Solute neutral amino acid transporter 5 (SNAT5/SN2) is a member of the System N family, expressed in glial cells in the adult brain, able to transport glutamine, histidine or glycine among other substrates. Its tight association with synapses and its electroneutral mode of operation that allows the bidirectional movement of substrates, supports the idea that this transporter participates in the function of the glutamine-glutamate cycle between neurons and glia. Moreover, SNAT5/SN2 might contribute to the regulation of glycine concentration in glutamatergic synapses and, therefore, to the functioning of the N-methyl-d-aspartate (NMDA) subtype of glutamate receptors. Ontogenic maturation of these synapses occurs postnatally through the coordinate expression of a large number of receptors, transporters, structural and regulatory proteins that ensure the correct operation of the excitatory pathways in the central nervous system. Since the temporal pattern of expression of SNAT5/SN2 is unknown, we analyzed it by immunoblot and immunohistochemical techniques. Results indicate that the expression of SNAT5/SN2 is triggered between the second and third postnatal week in the cerebral cortex, in parallel to the expression of the vesicular glutamate transporter vGLUT1 and the glial glutamate transporter GLT1/EAAT2. In the cerebellum, this process occurs about one week later than in the cerebral cortex. Immunohistochemical staining of cortical sections shows that from postnatal day 14 to adulthood the transporter was expressed exclusively in glial cells. Our results are consistent with the idea that SNAT5/SN2 expression is coordinated with that of other proteins necessary for the operation of glutamatergic synapses and reinforce the existence of a regulatory cross-talk between neurons and glia that orchestrates the building up of these synapses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Resampling-Based Empirical Bayes Multiple Testing Procedures for Controlling Generalized Tail Probability and Expected Value Error Rates: Focus on the False Discovery Rate and Simulation Study

PubMed Central

Dudoit, Sandrine; Gilbert, Houston N.; van der Laan, Mark J.

2014-01-01

Summary This article proposes resampling-based empirical Bayes multiple testing procedures for controlling a broad class of Type I error rates, defined as generalized tail probability (gTP) error rates, gTP(q, g) = Pr(g(Vn, Sn) > q), and generalized expected value (gEV) error rates, gEV(g) = E[g(Vn, Sn)], for arbitrary functions g(Vn, Sn) of the numbers of false positives Vn and true positives Sn. Of particular interest are error rates based on the proportion g(Vn, Sn) = Vn/(Vn + Sn) of Type I errors among the rejected hypotheses, such as the false discovery rate (FDR), FDR = E[Vn/(Vn + Sn)]. The proposed procedures offer several advantages over existing methods. They provide Type I error control for general data generating distributions, with arbitrary dependence structures among variables. Gains in power are achieved by deriving rejection regions based on guessed sets of true null hypotheses and null test statistics randomly sampled from joint distributions that account for the dependence structure of the data. The Type I error and power properties of an FDR-controlling version of the resampling-based empirical Bayes approach are investigated and compared to those of widely-used FDR-controlling linear step-up procedures in a simulation study. The Type I error and power trade-off achieved by the empirical Bayes procedures under a variety of testing scenarios allows this approach to be competitive with or outperform the Storey and Tibshirani (2003) linear step-up procedure, as an alternative to the classical Benjamini and Hochberg (1995) procedure. PMID:18932138

Factors Affecting Selectivity of Brilliant Green-Phenol Red Agar for Salmonellae

PubMed Central

Moats, W. A.; Kinner, J. A.

1974-01-01

Commercial brilliant green (BG)-sulfa agar was found to be nonselective toward a test series of Enterobacteriaceae. Various formulations of BG were prepared by using Trypticase soy agar (BBL) as a base. Results were more reproducible when BG dye was added after sterilization than before. Sulfonamides improved selectivity as compared with brilliant green alone. Sulfanilamide (SN) was slightly more selective for salmonellae than other sulfonamides tested. Bile salts and sodium dodecyl sulfate markedly reduced the toxicity of BG to all the test bacteria. Enterobacter strains were most difficult to inhibit. A combination of 5 mg of BG and 1 g of SN/liter prevented growth of Proteus mirabilis and Escherichia coli and retarded growth of Enterobacter strains. The BG-SN agars were superior in selectivity to a series of commercial agars tested, and numbers of salmonellae recovered on BG-SN agar and Trypticase soy agar (BBL) were the same. Brilliant green agars with various degrees of selectivity are described. PMID:4589120

Predicting the Drop Performance of Solder Joints by Evaluating the Elastic Strain Energy from High-Speed Ball Pull Tests

NASA Astrophysics Data System (ADS)

You, Taehoon; Kim, Yunsung; Kim, Jina; Lee, Jaehong; Jung, Byungwook; Moon, Jungtak; Choe, Heeman

2009-03-01

Despite being expensive and time consuming, board-level drop testing has been widely used to assess the drop or impact resistance of the solder joints in handheld microelectronic devices, such as cellphones and personal digital assistants (PDAs). In this study, a new test method, which is much simpler and quicker, is proposed. The method involves evaluating the elastic strain energy and relating it to the impact resistance of the solder joint by considering the Young’s modulus of the bulk solder and the fracture stress of the solder joint during a ball pull test at high strain rates. The results show that solder joints can be ranked in order of descending elastic strain energy as follows: Sn-37Pb, Sn-1Ag-0.5Cu, Sn-3Ag-0.5Cu, and Sn-4Ag-0.5Cu. This order is consistent with the actual drop performances of the samples.

Performance of the first short model 150 mm aperture Nb$$_3$$Sn Quadrupole MQXFS for the High- Luminosity LHC upgrade

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

Chlachidze, G.; et al.

2016-08-30

The US LHC Accelerator Research Program (LARP) and CERN combined their efforts in developing Nb3Sn magnets for the High-Luminosity LHC upgrade. The ultimate goal of this collaboration is to fabricate large aperture Nb3Sn quadrupoles for the LHC interaction regions (IR). These magnets will replace the present 70 mm aperture NbTi quadrupole triplets for expected increase of the LHC peak luminosity by a factor of 5. Over the past decade LARP successfully fabricated and tested short and long models of 90 mm and 120 mm aperture Nb3Sn quadrupoles. Recently the first short model of 150 mm diameter quadrupole MQXFS was builtmore » with coils fabricated both by the LARP and CERN. The magnet performance was tested at Fermilab’s vertical magnet test facility. This paper reports the test results, including the quench training at 1.9 K, ramp rate and temperature dependence studies.« less

Photocatalytic degradation of methylene blue on Sn-doped titania nanoparticles synthesized by solution combustion route

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

Bhange, P.D., E-mail: pallavi.ncl@gmail.com; Awate, S.V.; Gholap, R.S.

2016-04-15

Highlights: • Series of Sn-doped titania nanoparticles were prepared by solution combustion synthesis method. • Sn-doped titania nanoparticles were tested for degradation of MB under UV light irradiation. • The maximum Sn doping in the TiO{sub 2} lattice is found to be less than 10%. • The crystallite size decreases with increase in the Sn content. • The doping of Sn into TiO{sub 2} lattice hinders the recombination of electrons and holes thus enhance the photocatalytic activity. - Abstract: Series of tin-doped titania nanoparticles with varying tin content in the range 0–20 mol% have been prepared by solution combustion synthesismore » route using urea as a fuel. The structure, surface morphology and optical activity of Sn-doped TiO{sub 2} nanoparticles were investigated by various analytical techniques such as powder XRD, SEM, TEM, UV–vis and N{sub 2} adsorption study. The crystalline structures of the various phases were studied by rietveld refinement of the XRD data. The photocatalytic performance of Sn-doped titania nanoparticles were tested for degradation of MB under UV and visible light irradiation. The results reveal that the photocatalytic activity increases with increase in tin content which may be due to decrease in crystallite size with increase in surface area. The doping of Sn into TiO{sub 2} lattice hinders the recombination of electrons and holes thus enhance the quantum efficiency of photocatalytic reaction.« less

Wafer-level Cu-Sn micro-joints with high mechanical strength and low Sn overflow

NASA Astrophysics Data System (ADS)

Duan, Ani; Luu, Thi-Thuy; Wang, Kaiying; Aasmundtveit, Knut; Hoivik, Nils

2015-09-01

In this paper, we report wafer-level bonding using solid-liquid inter-diffusion (SLID) processes for fabricating micro-joints Cu-Sn at low temperature (270 °C). The evolution of multilayer Cu/Sn to micro-joint alloys has been characterized by optical microscopy and mechanical die-shear testing. The Cu-Sn joints with line width from 80 to 200 μm prove to be reliable packaging materials for bonding vacuum micro-cavities with controllable Sn overflow, as well as high mechanical strength (>70 MPa). A thermodynamic model has been performed to further understand the formation of Cu-Sn intermetallic alloys. There are two important findings for this work: 1) Using a two-step temperature profile may significantly reduce the amount of Sn overflow; 2) for packaging, a bond frame width greater than 80 μm will result in high yield.

Effects of PCB Pad Metal Finishes on the Cu-Pillar/Sn-Ag Micro Bump Joint Reliability of Chip-on-Board (COB) Assembly

NASA Astrophysics Data System (ADS)

Kim, Youngsoon; Lee, Seyong; Shin, Ji-won; Paik, Kyung-Wook

2016-06-01

While solder bumps have been used as the bump structure to form the interconnection during the last few decades, the continuing scaling down of devices has led to a change in the bump structure to Cu-pillar/Sn-Ag micro-bumps. Cu-pillar/Sn-Ag micro-bump interconnections differ from conventional solder bump interconnections in terms of their assembly processing and reliability. A thermo-compression bonding method with pre-applied b-stage non-conductive films has been adopted to form solder joints between Cu pillar/Sn-Ag micro bumps and printed circuit board vehicles, using various pad metal finishes. As a result, various interfacial inter-metallic compounds (IMCs) reactions and stress concentrations occur at the Cu pillar/Sn-Ag micro bumps joints. Therefore, it is necessary to investigate the influence of pad metal finishes on the structural reliability of fine pitch Cu pillar/Sn-Ag micro bumps flip chip packaging. In this study, four different pad surface finishes (Thin Ni ENEPIG, OSP, ENEPIG, ENIG) were evaluated in terms of their interconnection reliability by thermal cycle (T/C) test up to 2000 cycles at temperatures ranging from -55°C to 125°C and high-temperature storage test up to 1000 h at 150°C. The contact resistances of the Cu pillar/Sn-Ag micro bump showed significant differences after the T/C reliability test in the following order: thin Ni ENEPIG > OSP > ENEPIG where the thin Ni ENEPIG pad metal finish provided the best Cu pillar/Sn-Ag micro bump interconnection in terms of bump joint reliability. Various IMCs formed between the bump joint areas can account for the main failure mechanism.

Evolution of the Deformation Behavior of Sn-Rich Solders during Cyclic Fatigue

NASA Astrophysics Data System (ADS)

Wentlent, Luke Arthur

Continuous developments in the electronics industry have provided a critical need for a quantitative, fundamental understanding of the behavior of SnAgCu (SAC) solders in both isothermal and thermal fatigue conditions. This study examines the damage behavior of Sn-based solders in a constant amplitude and variable amplitude environment. In addition, damage properties are correlated with crystal orientation and slip behavior. Select solder joints were continuously characterized and tested repeatedly in order to eliminate the joint to joint variation due to the anisotropy of beta-Sn. Characterization was partitioned into three different categories: effective properties and slip behavior, creep mechanisms and crystal morphology development, and atomic behavior and evolution. Active slip systems were correlated with measured properties. Characterization of the mechanical behavior was performed by the calculation and extrapolation of the elastic modulus, work, effective stiffness, Schmid factors, and time-dependent plasticity (creep). Electron microscopy based characterization methods included Scanning Electron Microscopy (SEM), Electron Backscattering Diffraction (EBSD), and Transmission Electron Microscopy (TEM). Testing showed a clear evolution of the steady-state creep mechanism when the cycling amplitudes were varied, from dislocation controlled to diffusion controlled creep. Dislocation behavior was examined and shown to evolve differently in single amplitude vs. variable amplitude testing. Finally, the mechanism of the recrystallization behavior of the beta-Sn was observed. This work fills a gap in the literature, providing a systematic study which identifies how the damage behavior in Sn-alloys depends upon the previous damage. A link is made between the observed creep behavior and the dislocation observations, providing a unified picture. Information developed in this work lays a stepping stone to future fundamental analyses as well as clarifying aspects of the mechanistic behavior of Sn and Sn-based alloys.

Microstructural effects on constitutive and fatigue fracture behavior of TinSilverCopper solder

NASA Astrophysics Data System (ADS)

Tucker, Jonathon P.

As microelectronic package construction becomes more diverse and complex, the need for accurate, geometry-independent material constitutive and failure models increases. Evaluations of packages based on accelerated environmental tests (such as accelerated thermal cycling or power cycling) only provide package-dependent reliability information. In addition, extrapolations of such test data to life predictions under field conditions are often empirical. Besides geometry, accelerated environmental test data must account for microstructural factors such as alloy composition or isothermal aging condition, resulting in expensive experimental variation. In this work, displacement-controlled, creep, and fatigue lap shear tests are conducted on specially designed SnAgCu test specimens with microstructures representative to those found in commercial microelectronic packages. The data are used to develop constitutive and fatigue fracture material models capable of describing deformation and fracture behavior for the relevant temperature and strain rate ranges. Furthermore, insight is provided into the microstructural variation of solder joints and the subsequent effect on material behavior. These models are appropriate for application to packages of any geometrical construction. The first focus of the thesis is on Pb-mixed SnAgCu solder alloys. During the transition from Pb-containing solders to Pb-free solders, joints composed of a mixture of SnPb and SnAgCu often result from either mixed assemblies or rework. Three alloys of 1, 5 and 20 weight percent Pb were selected so as to represent reasonable ranges of Pb contamination expected from different 63Sn37Pb components mixed with Sn3.0Ag0.5Cu. Displacement-controlled (constant strain rate) and creep tests were performed at temperatures of 25°C, 75°C, and 125°C using a double lap shear test setup that ensures a nearly homogeneous state of plastic strain at the joint interface. Rate-dependent constitutive models for Pb-contaminated SnAgCu solder alloys ranging from the traditional time-hardening creep model to the viscoplastic Anand model are described. The second focus of the thesis is on fatigue damage accumulation in SnAgCu solder alloys. While, typical fatigue fracture models are empirical, recently a non-empirical model termed Maximum Entropy Fracture Model (MEFM) was proposed. MEFM is a thermodynamically consistent and information theory inspired damage accumulation theory for ductile solids. This model has been validated recently for Sn3.8Ag0.7Cu solder alloy, and uses a single damage accumulation parameter to relate the probability of fracture to accumulated entropic dissipation. Isothermal cycling fatigue tests on Sn3.0Ag0.5Cu and mixed SnPb/Sn3.0Ag0.5Cu solder alloys at varying strain rates and temperatures are conducted using a custom-built microscale mechanical tester capable of submicron displacement resolution. MEFM is applied here in conjunction with the Anand viscoplasticity model to predict the softening occurring over successive cycles as a result of damage accumulation. The damage accumulation parameters for Sn3.0Ag0.5Cu in different aged states are related to a microstructural parameter which quantitatively describes the state of coarsening. In addition, damage accumulation parameters for the three mixed solder alloys are reported. This approach allows for a non-empirical prediction of both constitutive and fracture behavior of packages of different geometries and different microstructural states under thermo-mechanical fatigue. Approaches to solder joint reliability predictions from materials science and mechanics perspectives differ dramatically. Materials science methods identify key failure mechanisms, but most models cannot predict failure. In contrast, mechanics approaches often provide estimates of joint lifetime, but fail to provide insight into microstructural influences. This work attempts to connect the two fields by relating constitutive behavior and fatigue fracture models for different alloys and aging conditions to one or more microstructural parameters.

Solid cryogen: a cooling system for future MgB2 MRI magnet.

PubMed

Patel, Dipak; Hossain, Md Shahriar Al; Qiu, Wenbin; Jie, Hyunseock; Yamauchi, Yusuke; Maeda, Minoru; Tomsic, Mike; Choi, Seyong; Kim, Jung Ho

2017-03-02

An efficient cooling system and the superconducting magnet are essential components of magnetic resonance imaging (MRI) technology. Herein, we report a solid nitrogen (SN 2 ) cooling system as a valuable cryogenic feature, which is targeted for easy usability and stable operation under unreliable power source conditions, in conjunction with a magnesium diboride (MgB 2 ) superconducting magnet. The rationally designed MgB 2 /SN 2 cooling system was first considered by conducting a finite element analysis simulation, and then a demonstrator coil was empirically tested under the same conditions. In the SN 2 cooling system design, a wide temperature distribution on the SN 2 chamber was observed due to the low thermal conductivity of the stainless steel components. To overcome this temperature distribution, a copper flange was introduced to enhance the temperature uniformity of the SN 2 chamber. In the coil testing, an operating current as high as 200 A was applied at 28 K (below the critical current) without any operating or thermal issues. This work was performed to further the development of SN 2 cooled MgB 2 superconducting coils for MRI applications.

Solid cryogen: a cooling system for future MgB2 MRI magnet

NASA Astrophysics Data System (ADS)

Patel, Dipak; Hossain, Md Shahriar Al; Qiu, Wenbin; Jie, Hyunseock; Yamauchi, Yusuke; Maeda, Minoru; Tomsic, Mike; Choi, Seyong; Kim, Jung Ho

2017-03-01

An efficient cooling system and the superconducting magnet are essential components of magnetic resonance imaging (MRI) technology. Herein, we report a solid nitrogen (SN2) cooling system as a valuable cryogenic feature, which is targeted for easy usability and stable operation under unreliable power source conditions, in conjunction with a magnesium diboride (MgB2) superconducting magnet. The rationally designed MgB2/SN2 cooling system was first considered by conducting a finite element analysis simulation, and then a demonstrator coil was empirically tested under the same conditions. In the SN2 cooling system design, a wide temperature distribution on the SN2 chamber was observed due to the low thermal conductivity of the stainless steel components. To overcome this temperature distribution, a copper flange was introduced to enhance the temperature uniformity of the SN2 chamber. In the coil testing, an operating current as high as 200 A was applied at 28 K (below the critical current) without any operating or thermal issues. This work was performed to further the development of SN2 cooled MgB2 superconducting coils for MRI applications.

The function of Sn(II)-apatite as a Tc immobilizing agent

NASA Astrophysics Data System (ADS)

Asmussen, R. Matthew; Neeway, James J.; Lawter, Amanda R.; Levitskaia, Tatiana G.; Lukens, Wayne W.; Qafoku, Nikolla P.

2016-11-01

At the U.S. Department of Energy Hanford Site, Tc-99 is a component of low-activity waste (LAW) fractions of the nuclear tank waste and removal of Tc from LAW streams would greatly benefit the site remediation process. In this study, we investigated the removal of Tc(VII), as pertechnetate, from deionized water (DIW) and a LAW simulant through batch sorption testing and solid phase characterization using tin (II) apatite (Sn-A) and SnCl2. Sn-A showed higher levels of Tc removal from both DIW and LAW simulant. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/XEDS) and X-ray absorption spectroscopy (XAS) of reacted Sn-A in DIW showed that TcO4- is reduced to Tc(IV) on the Sn-A surface. The performance of Sn-A in the LAW simulant was lowered due to a combined effect of the high alkalinity, which lead to an increased dissolution of Sn from the Sn-A, and a preference for the reduction of Cr(VI).

Balmer Filaments in Tycho’s Supernova Remnant: An Interplay between Cosmic-ray and Broad-neutral Precursors

NASA Astrophysics Data System (ADS)

Knežević, Sladjana; Läsker, Ronald; van de Ven, Glenn; Font, Joan; Raymond, John C.; Bailer-Jones, Coryn A. L.; Beckman, John; Morlino, Giovanni; Ghavamian, Parviz; Hughes, John P.; Heng, Kevin

2017-09-01

We present Hα spectroscopic observations and detailed modeling of the Balmer filaments in the supernova remnant (SNR) Tycho (SN 1572). We used GH α FaS (Galaxy Hα Fabry-Pérot Spectrometer) on the William Herschel Telescope with a 3.‧4 × 3.‧4 field of view, 0.″2 pixel scale, and {σ }{instr}=8.1 km s-1 resolution at 1″ seeing for ˜10 hr, resulting in 82 spatial-spectral bins that resolve the narrow Hα line in the entire SN 1572 northeastern rim. For the first time, we can therefore mitigate artificial line broadening from unresolved differential motion and probe Hα emission parameters in varying shock and ambient medium conditions. Broad Hα line remains unresolved within spectral coverage of 392 km s-1. We employed Bayesian inference to obtain reliable parameter confidence intervals and to quantify the evidence for models with multiple line components. The median Hα narrow-line (NL) FWHM of all bins and models is {W}{NL}=(54.8+/- 1.8) km s-1 at the 95% confidence level, varying within [35, 72] km s-1 between bins and clearly broadened compared to the intrinsic (thermal) ≈20 km s-1. Possible line splits are accounted for, significant in ≈ 18 % of the filament, and presumably due to remaining projection effects. We also find widespread evidence for intermediate-line emission of a broad-neutral precursor, with a median {W}{IL}=(180+/- 14) km s-1 (95% confidence). Finally, we present a measurement of the remnant’s systemic velocity, {V}{LSR}=-34 km s-1, and map differential line-of-sight motions. Our results confirm the existence and interplay of shock precursors in Tycho’s remnant. In particular, we show that suprathermal NL emission is near-universal in SN 1572, and that, in the absence of an alternative explanation, collisionless SNR shocks constitute a viable acceleration source for Galactic TeV cosmic-ray protons.

Synthesis, structure, and thermal properties of soluble hydrazinium germanium(IV) and tin(IV) selenide salts.

PubMed

Mitzi, David B

2005-05-16

The crystal structures of two hydrazinium-based germanium(IV) and tin(IV) selenide salts are determined. (N(2)H(5))(4)Ge(2)Se(6) (1) [I4(1)cd, a = 12.708(1) Angstroms, c = 21.955(2) Angstroms, Z = 8] and (N(2)H(4))(3)(N(2)H(5))(4)Sn(2)Se(6) (2) [P, a = 6.6475(6) Angstroms, b = 9.5474(9) Angstroms, c = 9.8830(10) Angstroms, alpha = 94.110(2) degrees, beta = 99.429(2) degrees, gamma = 104.141(2) degrees, Z = 1] each consist of anionic dimers of edge-sharing metal selenide tetrahedra, M(2)Se(6)(4-) (M = Ge or Sn), separated by hydrazinium cations and, for 2, additional neutral hydrazine molecules. Substantial hydrogen bonding exists among the hydrazine/hydrazinium molecules as well as between the hydrazinium cations and the selenide anions. Whereas the previously reported tin(IV) sulfide system, (N(2)H(5))(4)Sn(2)S(6), decomposes cleanly to microcrystalline SnS(2) when heated to 200 degrees C in an inert atmosphere, higher temperatures (>300 degrees C) are required to dissociate selenium from 1 and 2 for the analogous preparations of single-phase metal selenides. The metal chalcogenide salts are highly soluble in hydrazine, as well as in a variety of amines and DMSO, highlighting the potential usefulness of these compounds as precursors for the solution deposition of the corresponding metal chalcogenide films.

Defect physics in intermediate-band materials: Insights from an optimized hybrid functional

NASA Astrophysics Data System (ADS)

Han, Miaomiao; Zeng, Zhi; Frauenheim, Thomas; Deák, Peter

2017-10-01

Despite the efforts to implement the idea of a deep level impurity intermediate band (IB) into bulk solar cell materials, a breakthrough in efficiency increase has not yet been achieved. Taking Sn-doped CuGaS2 as an example, we investigate the problem here from the perspective of defect physics, considering all possible charge states of the dopant and its interaction with native defects. Using an optimized hybrid functional, we find that SnGa has not only a donor-type (+/0), but also an acceptor-type (0 /- ) charge transition level. We estimate the probability of the optical transition of an electron from/to the neutral defect to/from the conduction-band edge to be about equal, therefore, the lifetimes of the excited carriers are probably quite short, limiting the enhancement of the photocurrent. In addition, we find that doping with SnGa leads to the spontaneous formation of the intrinsic acceptor CuGa defects which passivate the donor SnGa and pin the Fermi level to a position (1.4 eV above the valence-band edge) where both defects are ionized. As a result, the possibility of absorption in the middle of the visible range gets lost. These two recombination and passivation mechanisms appear to be quite likely the case for other donors and other similar host materials as well, explaining some of the experimental bottlenecks with IB solar cells based on deep level impurities.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: METSAT A1 Signal Processor (P/N 1331670-2, S/N F03)

NASA Technical Reports Server (NTRS)

Lund, D.

1998-01-01

This report presents a description of tests performed, and the test data, for the A1 METSAT Signal Processor Assembly PN: 1331679-2, S/N F03. This assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure." The objective is to demonstrate functionality of the signal processor prior to instrument integration.

A Comparative Study on the Microstructure and Mechanical Properties of Cu6Sn5 and Cu3Sn Joints Formed by TLP Soldering With/Without the Assistance of Ultrasonic Waves

NASA Astrophysics Data System (ADS)

Zhao, H. Y.; Liu, J. H.; Li, Z. L.; Song, X. G.; Zhao, Y. X.; Niu, H. W.; Tian, H.; Dong, H. J.; Feng, J. C.

2018-07-01

In this study, the microstructure and mechanical properties of Cu6Sn5 and Cu3Sn intermetallic joints, formed by the transient liquid phase (TLP) soldering process with and without the assistance of ultrasonic waves (USWs), were compared. After the application of USWs in the TLP soldering process, Cu-Sn intermetallic compounds (IMCs) exhibited a novel noninterfacial growth pattern in the molten solder interlayer. The resulting Cu6Sn5 and Cu3Sn joints consisted of refined equiaxed IMC grains with average sizes of 3 and 2.3 µm, respectively. The Cu6Sn5 grains in the ultrasonically soldered intermetallic joints demonstrated uniform mechanical properties with elastic modulus and hardness values of 123.0 and 5.98 GPa, respectively, while those of Cu3Sn grains were 133.9 and 5.08 GPa, respectively. The shear strengths of ultrasonically soldered Cu6Sn5 and Cu3Sn joints were measured to be 60 and 65 MPa, respectively, higher than that for reflow-soldered intermetallic joints. Ultrasonically soldered Cu6Sn5 and Cu3Sn joints both exhibited a combination of transgranular and intergranular fractures during shear testing.

A Comparative Study on the Microstructure and Mechanical Properties of Cu6Sn5 and Cu3Sn Joints Formed by TLP Soldering With/Without the Assistance of Ultrasonic Waves

NASA Astrophysics Data System (ADS)

Zhao, H. Y.; Liu, J. H.; Li, Z. L.; Song, X. G.; Zhao, Y. X.; Niu, H. W.; Tian, H.; Dong, H. J.; Feng, J. C.

2018-05-01

In this study, the microstructure and mechanical properties of Cu6Sn5 and Cu3Sn intermetallic joints, formed by the transient liquid phase (TLP) soldering process with and without the assistance of ultrasonic waves (USWs), were compared. After the application of USWs in the TLP soldering process, Cu-Sn intermetallic compounds (IMCs) exhibited a novel noninterfacial growth pattern in the molten solder interlayer. The resulting Cu6Sn5 and Cu3Sn joints consisted of refined equiaxed IMC grains with average sizes of 3 and 2.3 µm, respectively. The Cu6Sn5 grains in the ultrasonically soldered intermetallic joints demonstrated uniform mechanical properties with elastic modulus and hardness values of 123.0 and 5.98 GPa, respectively, while those of Cu3Sn grains were 133.9 and 5.08 GPa, respectively. The shear strengths of ultrasonically soldered Cu6Sn5 and Cu3Sn joints were measured to be 60 and 65 MPa, respectively, higher than that for reflow-soldered intermetallic joints. Ultrasonically soldered Cu6Sn5 and Cu3Sn joints both exhibited a combination of transgranular and intergranular fractures during shear testing.

SnSAG5 is an alternative surface antigen of Sarcocystis neurona strains that is mutually exclusive to SnSAG1.

PubMed

Crowdus, Carolyn A; Marsh, Antoinette E; Saville, Willliam J; Lindsay, David S; Dubey, J P; Granstrom, David E; Howe, Daniel K

2008-11-25

Sarcocystis neurona is an obligate intracellular parasite that causes equine protozoal myeloencephalitis (EPM). Previous work has identified a gene family of paralogous surface antigens in S. neurona called SnSAGs. These surface proteins are immunogenic in their host animals, and are therefore candidate molecules for development of diagnostics and vaccines. However, SnSAG diversity exists in strains of S. neurona, including the absence of the major surface antigen gene SnSAG1. Instead, sequence for an alternative SnSAG has been revealed in two of the SnSAG1-deficient strains. Herein, we present data characterizing this new surface protein, which we have designated SnSAG5. The results indicated that the protein encoded by the SnSAG5 sequence is indeed a surface-associated molecule that has characteristics consistent with the other SAGs identified in S. neurona and related parasites. Importantly, Western blot analyses of a collection of S. neurona strains demonstrated that 6 of 13 parasite isolates express SnSAG5 as a dominant surface protein instead of SnSAG1. Conversely, SnSAG5 was not detected in SnSAG1-positive strains. One strain, which was isolated from the brain of a sea otter, did not express either SnSAG1 or SnSAG5. Genetic analysis with SnSAG5-specific primers confirmed the presence of the SnSAG5 gene in Western blot-positive strains, while also suggesting the presence of a novel SnSAG sequence in the SnSAG1-deficient, SnSAG5-deficient otter isolate. The findings provide further indication of S. neurona strain diversity, which has implications for diagnostic testing and development of vaccines against EPM as well as the population biology of Sarcocystis cycling in the opossum definitive host.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: AMSU-A1 Antenna Drive Subsystem, PN 1331720-2, S/N 106

NASA Technical Reports Server (NTRS)

Luu, D.

1999-01-01

This is the Performance Verification Report, AMSU-A1 Antenna Drive Subsystem, P/N 1331720-2, S/N 106, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The antenna drive subsystem of the METSAT AMSU-A1, S/N 106, P/N 1331720-2, completed acceptance testing per A-ES Test Procedure AE-26002/lD. The test included: Scan Motion and Jitter, Pulse Load Bus Peak Current and Rise Time, Resolver Reading and Position Error, Gain/ Phase Margin, and Operational Gain Margin. The drive motors and electronic circuitry were also tested at the component level. The drive motor test includes: Starting Torque Test, Motor Commutation Test, Resolver Operation/ No-Load Speed Test, and Random Vibration. The electronic circuitry was tested at the Circuit Card Assembly (CCA) level of production; each test exercised all circuit functions. The transistor assembly was tested during the W3 cable assembly (1356941-1) test.

Nano SnO 2-Al 2O 3 mixed oxide and SnO 2-Al 2O 3-carbon composite oxides as new and novel electrodes for supercapacitor applications

NASA Astrophysics Data System (ADS)

Jayalakshmi, M.; Venugopal, N.; Raja, K. Phani; Rao, M. Mohan

New nano-materials like SnO 2-Al 2O 3 and SnO 2-Al 2O 3-carbon were synthesized by a single step hydrothermal method in searching for novel mixed oxides with high electrochemical double layer capacitance. A SnO 2-Al 2O 3-carbon sample was calcined at 600 °C and tested for its performance. The source of carbon was tetrapropyl ammonium hydroxide. The capacitive behavior of SnO 2 was compared to the performance of SnO 2-Al 2O 3, SnO 2-Al 2O 3-carbon and calcined SnO 2-Al 2O 3-carbon using the techniques of cyclic voltammetry, double potential step, chronopotentiometry and E-log I polarization. In 0.1 M NaCl solutions, SnO 2-Al 2O 3 gave the best performance with a value of 119 Fg -1 and cycled 1000 times. The nano-material mixed oxides were characterized by TEM, XRD, ICP-AES and SEM-EDAX.

Interfacial Reaction and Mechanical Properties of Sn-Bi Solder joints

PubMed Central

Huang, Ying; Zhang, Zhijie

2017-01-01

Sn-Bi solder with different Bi content can realize a low-to-medium-to-high soldering process. To obtain the effect of Bi content in Sn-Bi solder on the microstructure of solder, interfacial behaviors in solder joints with Cu and the joints strength, five Sn-Bi solders including Sn-5Bi and Sn-15Bi solid solution, Sn-30Bi and Sn-45Bi hypoeutectic and Sn-58Bi eutectic were selected in this work. The microstructure, interfacial reaction under soldering and subsequent aging and the shear properties of Sn-Bi solder joints were studied. Bi content in Sn-Bi solder had an obvious effect on the microstructure and the distribution of Bi phases. Solid solution Sn-Bi solder was composed of the β-Sn phases embedded with fine Bi particles, while hypoeutectic Sn-Bi solder was composed of the primary β-Sn phases and Sn-Bi eutectic structure from networked Sn and Bi phases, and eutectic Sn-Bi solder was mainly composed of a eutectic structure from short striped Sn and Bi phases. During soldering with Cu, the increase on Bi content in Sn-Bi solder slightly increased the interfacial Cu6Sn5 intermetallic compound (IMC)thickness, gradually flattened the IMC morphology, and promoted the accumulation of more Bi atoms to interfacial Cu6Sn5 IMC. During the subsequent aging, the growth rate of the IMC layer at the interface of Sn-Bi solder/Cu rapidly increased from solid solution Sn-Bi solder to hypoeutectic Sn-Bi solder, and then slightly decreased for Sn-58Bi solder joints. The accumulation of Bi atoms at the interface promoted the rapid growth of interfacial Cu6Sn5 IMC layer in hypoeutectic or eutectic Sn-Bi solder through blocking the formation of Cu6Sn5 in solder matrix and the transition from Cu6Sn5 to Cu3Sn. Ball shear tests on Sn-Bi as-soldered joints showed that the increase of Bi content in Sn-Bi deteriorated the shear strength of solder joints. The addition of Bi into Sn solder was also inclined to produce brittle morphology with interfacial fracture, which suggests that the addition of Bi increased the shear resistance strength of Sn-Bi solder. PMID:28792440

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: METSAT AMSU-A2 Antenna Drive Subsystem, P/N 1331200-2, S/N 106

NASA Technical Reports Server (NTRS)

Higgins, T.

1998-01-01

An antenna drive subsystem test was performed on the METSAT AMSU-A2 S/N 106 instrument. The objective of the test was to demonstrate compliance with applicable paragraphs of AMSU-A specifications S480-80. Tests were conducted at both the subassembly and instrument level.

Tin-decorated ruthenium nanoparticles: a way to tune selectivity in hydrogenation reaction

NASA Astrophysics Data System (ADS)

Bonnefille, Eric; Novio, Fernando; Gutmann, Torsten; Poteau, Romuald; Lecante, Pierre; Jumas, Jean-Claude; Philippot, Karine; Chaudret, Bruno

2014-07-01

Two series of ruthenium nanoparticles stabilized either by a polymer (polyvinylpyrrolidone; Ru/PVP) or a ligand (bisdiphenylphosphinobutane; Ru/dppb) were reacted with tributyltin hydride [(n-C4H9)3SnH] leading to tin-decorated ruthenium nanoparticles, Ru/PVP/Sn and Ru/dppb/Sn. The Sn/Ru molar ratio was varied in order to study the influence of the surface tin content on the properties of these new nanoparticles, by comparison with Ru/PVP and Ru/dppb. Besides HRTEM and WAXS analyses, spectroscopic techniques (IR, NMR and Mössbauer) combined with theoretical calculations and a simple catalytic test (styrene hydrogenation) allowed us to evidence the formation of μ3-bridging ``SnR'' groups on the ruthenium surface as well as to rationalize their influence on surface chemistry and catalytic activity.Two series of ruthenium nanoparticles stabilized either by a polymer (polyvinylpyrrolidone; Ru/PVP) or a ligand (bisdiphenylphosphinobutane; Ru/dppb) were reacted with tributyltin hydride [(n-C4H9)3SnH] leading to tin-decorated ruthenium nanoparticles, Ru/PVP/Sn and Ru/dppb/Sn. The Sn/Ru molar ratio was varied in order to study the influence of the surface tin content on the properties of these new nanoparticles, by comparison with Ru/PVP and Ru/dppb. Besides HRTEM and WAXS analyses, spectroscopic techniques (IR, NMR and Mössbauer) combined with theoretical calculations and a simple catalytic test (styrene hydrogenation) allowed us to evidence the formation of μ3-bridging ``SnR'' groups on the ruthenium surface as well as to rationalize their influence on surface chemistry and catalytic activity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00791c

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

Wen, Zhigang, E-mail: xh168688@126.com; State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083; Department of Chemistry and Chemical Engineering, Qiannan Normal College for Nationalities, Duyun 558000

SnO{sub 2} nanorod bundles were synthesized by hydrothermal method. Field-emission scanning electron microscopy and transmission electron microscopy images showed that the as-prepared flowerlike SnO{sub 2} nanorod bundles consist of tetragonal nanorods with size readily tunable. Their electrochemical properties and application as anode for lithium-ion battery were evaluated by galvanostatic discharge–charge testing and cycle voltammetry. SnO{sub 2} nanorod flowers possess improved discharge capacity of 694 mA h g{sup −1} up to 40th cycle at 0.1 C. - Highlights: ► The flowerlike SnO{sub 2} nanorod bundles were synthesized by hydrothermal method. ► SnO{sub 2} nanorod bundles with tunable size by controlling concentrationmore » of SnCl{sub 4}. ► A probable formation mechanism of SnO{sub 2} nanorod bundles has been proposed.« less

The North American Listening in Spatialized Noise-Sentences test (NA LiSN-S): normative data and test-retest reliability studies for adolescents and young adults.

PubMed

Brown, David K; Cameron, Sharon; Martin, Jeffrey S; Watson, Charlene; Dillon, Harvey

2010-01-01

The Listening in Spatialized Noise-Sentences test (LiSN-S; Cameron and Dillon, 2009) was originally developed to assess auditory stream segregation skills in children aged 6 to 11 yr with suspected central auditory processing disorder. The LiSN-S creates a three-dimensional auditory environment under headphones. A simple repetition-response protocol is used to assess a listener's speech reception threshold (SRT) for target sentences presented in competing speech maskers. Performance is measured as the improvement in SRT in dB gained when either pitch, spatial, or both pitch and spatial cues are incorporated in the maskers. A North American-accented version of the LiSN-S (NA LiSN-S) is available for use in the United States and Canada. To develop normative data for adolescents and adults on the NA LiSN-S, to compare these data with those of children aged 6 to 11 yr as documented in Cameron et al (2009), and to consolidate the child, adolescent, and adult normative and retest data to allow the software to be used with a wider population. In a descriptive design, normative data and test-retest reliability data were collected. One hundred and twenty normally hearing participants took part in the normative data study (67 adolescents aged 12 yr, 1 mo, to 17 yr, 10 mo, and 53 adults aged 19 yr, 10 mo, to 30 yr, 30 mo). Forty-nine participants returned between 1 and 4 mo after the initial assessment for retesting. Participants were recruited from sites in Cincinnati, Dallas, and Calgary. When combined with data collected from children aged 6 to 11 yr, a trend of improved performance as a function of increasing age was found across performance measures. ANOVA (analysis of variance) revealed a significant effect of age on performance. Planned contrasts revealed that there were no significant differences between adults and children aged 13 yr and older on the low-cue SRT; 14 yr and older on talker and spatial advantage; 15 yr and older on total advantage; and 16 yr and older on the high-cue SRT. Mean test-retest differences on the various NA LiSN-S performance measures for the combined child, adult, and adolescent data ranged from 0.05 to 0.5 dB. Paired comparisons revealed test-retest differences were not significant on any measure of the NA LiSN-S except low-cue SRT. Test-retest differences across measures did not differ as a function of age. Test and retest scores were significantly correlated for all NA LiSN-S measures. The ability to use either spatial or talker cues in isolation becomes adultlike by about 14 yr of age, whereas the ability to combine spatial and talker cues does not fully mature until closer to adulthood. By consolidating child, adolescent, and adult normative and retest data the NA LiSN-S can now been utilized to assess auditory processing skills in a wider population. American Academy of Audiology.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: METSAT A1 Signal Processor (P/N: 1331670-2, S/N: F04)

NASA Technical Reports Server (NTRS)

Lund, D.

1998-01-01

This report presents a description of the tests performed, and the test data, for the A1 METSAT Signal Processor Assembly PN: 1331679-2, S/N F04. The assembly was tested in accordance with AE-26754, "METSAT Signal Processor Scan Drive Test and Integration Procedure." The objective is to demonstrate functionality of the signal processor prior to instrument integration.

Photometric analysis of esthetically pleasant and unpleasant facial profile

PubMed Central

Fortes, Helena Nunes da Rocha; Guimarães, Thamirys Correia; Belo, Ivana Mara Lira; da Matta, Edgard Norões Rodrigues

2014-01-01

Objective To identify which linear, angular and proportionality measures could influence a profile to be considered esthetically pleasant or unpleasant, and to assess sexual dimorphism. Methods 150 standardized facial profile photographs of dental students of both sexes were obtained and printed on photographic paper. Ten plastic surgeons, ten orthodontists and ten layperson answered a questionnaire characterizing each profile as pleasant, acceptable or unpleasant. With the use of a score system, the 15 most pleasant and unpleasant profiles of each sex were selected. The photographs were scanned into AutoCAD computer software. Linear, angular and proportion measurements were obtained using the software tools. The average values between groups were compared by the Student's t-test and the Mann-Whitney test at 5%. Results The linear measures LL-S, LL-H, LL-E, LL-B and Pn-H showed statistically significant differences (p < 0.05). Statistical differences were also found in the angular measures G'.Pn.Pg', G'.Sn.Pg' and Sn.Me'.C and in the proportions G'-Sn:Sn-Me' and Sn-Gn':Gn'-C (p < 0.05). Differences between sexes were found for the linear measure Ala-Pn, angles G'-Pg'.N-Pn, Sn.Me'.C, and proportions Gn'-Sn:Sn-Me' and Ala-Pn:N'-Sn. (p < 0.05). Conclusion The anteroposterior position of the lower lip, the amount of nose that influences the profile, facial convexity, total vertical proportion and lip-chin proportion appear to influence pleasantness of facial profile. Sexual dimorphism was identified in nasal length, nasofacial and lower third of the face angles, total vertical and nasal height/length proportions. PMID:24945516

Photometric analysis of esthetically pleasant and unpleasant facial profile.

PubMed

Fortes, Helena Nunes da Rocha; Guimarães, Thamirys Correia; Belo, Ivana Mara Lira; da Matta, Edgard Norões Rodrigues

2014-01-01

To identify which linear, angular and proportionality measures could influence a profile to be considered esthetically pleasant or unpleasant, and to assess sexual dimorphism. 150 standardized facial profile photographs of dental students of both sexes were obtained and printed on photographic paper. Ten plastic surgeons, ten orthodontists and ten layperson answered a questionnaire characterizing each profile as pleasant, acceptable or unpleasant. With the use of a score system, the 15 most pleasant and unpleasant profiles of each sex were selected. The photographs were scanned into AutoCAD computer software. Linear, angular and proportion measurements were obtained using the software tools. The average values between groups were compared by the Student's t-test and the Mann-Whitney test at a significance level of 5%. The linear measures LL-S, LL-H, LL-E, LL-B and Pn-H showed statistically significant differences (p < 0.05). Statistical differences were also found in the angular measures G'.Pn.Pg', G'.Sn.Pg' and Sn.Me'.C and in the proportions G'-Sn:Sn-Me' and Sn-Gn':Gn'-C (p < 0.05). Differences between sexes were found for the linear measure Ala-Pn, angles G'-Pg'.N-Pn, Sn.Me'.C, and proportions Gn'-Sn:Sn-Me' and Ala-Pn:N'-Sn. (p < 0.05). The anteroposterior position of the lower lip, the amount of nose that influences the profile, facial convexity, total vertical proportion and lip-chin proportion appear to influence pleasantness of facial profile. Sexual dimorphism was identified in nasal length, nasofacial and lower third of the face angles, total vertical and nasal height/length proportions.

Host Galaxy Spectra of Stripped SN from the Palomar Transient Factory: SN Progenitor Diagnostics and the SN-GRB Connection

NASA Astrophysics Data System (ADS)

Modjaz, Maryam; Gal-Yam, Avishay; Arcavi, Iair

2011-02-01

Stripped core-collapse supernovae (Stripped SN) are powerful cosmic engines that energize and enrich the ISM and that sometimes accompany GRBs, but the exact mass and metallicity range of their massive progenitors is not known, nor the detailed physics of the explosion. With the harvest of 50 stripped SN from the innovative survey Palomar Transient Factory, we propose to conduct the first uniform and statistically significant study with SN from the same homogeneous and galaxy-unbiased survey in order to determine the environmental conditions that influence the various kinds of massive stellar deaths. By obtaining spectra of the immediate host environments of our sample of stripped SN, we will (1) measure local abundances in order to differentiate between the two progenitor scenarios for stripped SN and (2) derive stellar population ages, masses and star formation histories via detailed stellar population synthesis models. Moreover, we will test if natal chemical abundance has effects on basic SN characteristics, such as peak luminosity. Any observed trends will have ramifications on SN and GRB explosion models and imply important demographic SN considerations. Our dataset will provide a crucial complimentary set to host galaxy studies of long-duration GRBs and pave the way for host studies of transients and SN found via upcoming surveys such as LSST.

Electrical characteristics for Sn-Ag-Cu solder bump with Ti/Ni/Cu under-bump metallization after temperature cycling tests

NASA Astrophysics Data System (ADS)

Shih, T. I.; Lin, Y. C.; Duh, J. G.; Hsu, Tom

2006-10-01

Lead-free solder bumps have been widely used in current flip-chip technology (FCT) due to environmental issues. Solder joints after temperature cycling tests were employed to investigate the interfacial reaction between the Ti/Ni/Cu under-bump metallization and Sn-Ag-Cu solders. The interfacial morphology and quantitative analysis of the intermetallic compounds (IMCs) were obtained by electron probe microanalysis (EPMA) and field emission electron probe microanalysis (FE-EPMA). Various types of IMCs such as (Cu1-x,Agx)6Sn5, (Cu1-y,Agy)3Sn, and (Ag1-z,Cuz)3Sn were observed. In addition to conventional I-V measurements by a special sample preparation technique, a scanning electron microscope (SEM) internal probing system was introduced to evaluate the electrical characteristics in the IMCs after various test conditions. The electrical data would be correlated to microstructural evolution due to the interfacial reaction between the solder and under-bump metallurgy (UBM). This study demonstrated the successful employment of an internal nanoprobing approach, which would help further understanding of the electrical behavior within an IMC layer in the solder/UBM assembly.

Temperature relaxation in supernova remnants, revisited

NASA Technical Reports Server (NTRS)

Itoh, H.

1984-01-01

Some supernova remnants are expanding into a partially neutral medium. The neutral atoms which are engulfed by the fast blast shock are collisionally ionized to eject low-energy secondary electrons. Calculations are conducted of the temperature relaxation through Coulomb collisions among the secondary electrons, the shocked electrons, and the ions, assuming that the three species have Maxwellian velocity distributions. The results are applied to a self-similar blast wave. If the efficiency of collisionless electron heating at the shock front is high in young remnants such as Tycho, the secondary electrons may be much cooler than both the shocked electrons and the ions. In this case, the emergent X-ray continuum spectrum will have a two-temperature, or a power-law, appearance. This effect may have been observed in the bright rim of the remnant of SN 1006.

Safety and immunogenicity of a modified vaccinia Ankara vaccine using three immunization schedules and two modes of delivery: A randomized clinical non-inferiority trial.

PubMed

Jackson, Lisa A; Frey, Sharon E; El Sahly, Hana M; Mulligan, Mark J; Winokur, Patricia L; Kotloff, Karen L; Campbell, James D; Atmar, Robert L; Graham, Irene; Anderson, Evan J; Anderson, Edwin L; Patel, Shital M; Fields, Colin; Keitel, Wendy; Rouphael, Nadine; Hill, Heather; Goll, Johannes B

2017-03-23

To guide the use of modified vaccinia Ankara (MVA) vaccine in response to a release of smallpox virus, the immunogenicity and safety of shorter vaccination intervals, and administration by jet injector (JI), were compared to the standard schedule of administration on Days 1 and 29 by syringe and needle (S&N). Healthy adults 18-40years of age were randomly assigned to receive MVA vaccine subcutaneously by S&N on Days 1 and 29 (standard), Days 1 and 15, or Days 1 and 22, or to receive the vaccine subcutaneously by JI on Days 1 and 29. Blood was collected at four time points after the second vaccination for plaque reduction neutralization test (PRNT) (primary endpoint) and ELISA (secondary endpoint) antibody assays. For each subject, the peak PRNT (or ELISA) titer was defined by the highest PRNT (or ELISA) titer among all available measurements post second vaccination. Non-inferiority of a non-standard arm compared to the standard arm was met if the upper limit of the 98.33% confidence interval of the difference in the mean log 2 peak titers between the standard and non-standard arm was less than 1. Non-inferiority of the PRNT antibody response was not established for any of the three non-standard study arms. Non-inferiority of the ELISA antibody response was established for the Day 1 and 22 compressed schedule and for administration by JI. Solicited local reactions, such as redness and swelling, tended to be more commonly reported with JI administration. Four post-vaccination hypersensitivity reactions were observed. Evaluations of the primary endpoint of PRNT antibody responses do not support alternative strategies of administering MVA vaccine by S&N on compressed schedules or administration by JI on the standard schedule. clinicaltrials.gov Identifier: NCT01827371. Copyright © 2017. Published by Elsevier Ltd.

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

Bauer, R.; Ebersberger, B.; Kupfer, C.

SnAg solder bump is one bump type which is used to replace eutectic SnPb bumps. In this work tests have been done to characterize the reliability properties of this bump type. Electromigration (EM) tests, which were accelerated by high current and high temperature and high temperature storage (HTS) tests were performed. It was found that the reliability properties are sensitive to the material combinations in the interconnect stack. The interconnect stack includes substrate pad, pad finish, bump, underbump metallization (UBM) and the chip pad. Therefore separate test groups for SnAg bumps on Cu substrate pads with organic solderability preservative (OSP)more » finish and the identical bumps on pads with Ni/Au finish were used. In this paper the reliability test results and the corresponding failure analysis are presented. Some explanations about the differences in formation of intermetallic compounds (IMCs) are given.« less

Removal of Tin from Extreme Ultraviolet Collector Optics by an In-Situ Hydrogen Plasma

NASA Astrophysics Data System (ADS)

Elg, Daniel Tyler

Throughout the 1980s and 1990s, as the semiconductor industry upheld Moore's Law and continuously shrank device feature sizes, the wavelength of the lithography source remained at or below the resolution limit of the minimum feature size. Since 2001, however, the light source has been the 193nm ArF excimer laser. While the industry has managed to keep up with Moore's Law, shrinking feature sizes without shrinking the lithographic wavelength has required extra innovations and steps that increase fabrication time, cost, and error. These innovations include immersion lithography and double patterning. Currently, the industry is at the 14 nm technology node. Thus, the minimum feature size is an order of magnitude below the exposure wavelength. For the 10 nm node, triple and quadruple patterning have been proposed, causing potentially even more cost, fabrication time, and error. Such a trend cannot continue indefinitely in an economic fashion, and it is desirable to decrease the wavelength of the lithography sources. Thus, much research has been invested in extreme ultraviolet lithography (EUVL), which uses 13.5 nm light. While much progress has been made in recent years, some challenges must still be solved in order to yield a throughput high enough for EUVL to be commercially viable for high-volume manufacturing (HVM). One of these problems is collector contamination. Due to the 92 eV energy of a 13.5 nm photon, EUV light must be made by a plasma, rather than by a laser. Specifically, the industrially-favored EUV source topology is to irradiate a droplet of molten Sn with a laser, creating a dense, hot laser-produced plasma (LPP) and ionizing the Sn to (on average) the +10 state. Additionally, no materials are known to easily transmit EUV. All EUV light must be collected by a collector optic mirror, which cannot be guarded by a window. The plasmas used in EUV lithography sources expel Sn ions and neutrals, which degrade the quality of collector optics. The mitigation of this debris is one of the main problems facing potential manufacturers of EUV sources. which can damage the collector optic in three ways: sputtering, implantation, and deposition. The first two damage processes are irreversible and are caused by the high energies (1-10 keV) of the ion debris. Debris mitigation methods have largely managed to reduce this problem by using collisions with H2 buffer gas to slow down the energetic ions. However, deposition can take place at all ion and neutral energies, and no mitigation method can deterministically deflect all neutrals away from the collector. Thus, deposition still takes place, lowering the collector reflectivity and increasing the time needed to deliver enough EUV power to pattern a wafer. Additionally, even once EUV reaches HVM insertion, source power will need to be continually increased as feature sizes continue to shrink; this increase in source power may potentially come at a cost of increased debris. Thus, debris mitigation solutions that work for the initial generation of commercial EUVL systems may not be adequate for future generations. An in-situ technology to clean collector optics without source downtime is required. which will require an in-situ technology to clean collector optics. The novel cleaning solution described in this work is to create the radicals directly on the collector surface by using the collector itself to drive a capacitively-coupled hydrogen plasma. This allows for radical creation at the desired location without requiring any delivery system and without requiring any source downtime. Additionally, the plasma provides energetic radicals that aid in the etching process. This work will focus on two areas. First, it will focus on experimental collector cleaning and EUV reflectivity restoration. Second, it will focus on developing an understanding of the fundamental processes governing Sn removal. It will be shown that this plasma technique can clean an entire collector optic and restore EUV reflectivity to MLMs without damaging them. Additionally, it will be shown that, within the parameter space explored, the limiting factor in Sn etching is not hydrogen radical flux or SnH4 decomposition but ion energy flux. This will be backed up by experimental measurements, as well as a plasma chemistry model of the radical density and a 3D model of SnH4 transport and redeposition.

Tin Oxynitride Anodes by Atomic Layer Deposition for Solid-State Batteries

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

Stewart, David M.; Pearse, Alexander J.; Kim, Nam S.

Major advances in thin-film solid-state batteries (TFSSBs) may capitalize on 3D structuring using high-aspect-ratio substrates such as nanoscale pits, pores, trenches, flexible polymers, and textiles. This will require conformal processes such as atomic layer deposition (ALD) for every active functional component of the battery. In this paper, we explore the deposition and electrochemical properties of SnO 2, SnN y, and SnO xN y thin films as TFSSB anode materials, grown by ALD using tetrakisdimethylamido(tin), H 2O, and N 2 plasma as precursors. By controlling the dose ratio between H 2O and N 2, the N–O fraction can be tuned betweenmore » 0% N and 95% N. The electrochemical properties of these materials were tested across a composition range varying from pure SnO 2, to SnON intermediates, and pure SnNy. In TFSSBs, the SnNy anodes are found to be more stable during cycling than the SnO 2 or SnO xN y films, with an initial reversible capacity beyond that of Li–Sn alloying, retaining 75% of their capacity over 200 cycles compared to only 50% for SnO 2. Lastly, the performance of the SnO xN y anodes indicates that SnN y anodes should not be negatively impacted by small levels of O contamination.« less

Synthesis and characterization of Sn/zeolite and catalytic activity test in the esterification reaction of sludge oil

NASA Astrophysics Data System (ADS)

Alimuddin, Andi Hairil; Usman, Thamrin; Wahyuni, Nelly; Rudiyansyah, Prawatya, Yopa Eka; Astar, Ismail; Yustira, Yudi

2017-03-01

Synthesis of Sn-Zeolite has been made to use for esterification reaction of free fatty acids in sludge oil. Catalyst characterization was accomplished using X-Ray Diffraction (XRD), X-Ray Flourecence (XRF), and Fourier Transform Infra Red (FTIR). Catalyst Sn/zeolite was synthesized by impregnated Sn of SnCl2 into the zeolite. The amount of Sn impregnated base on the value of cation exchange capacity (CEC) of zeolites. Esterification reaction of fatty acids from sludge oil using Sn/Zeolite catalyst was did by variated the reaction time. XRD analysis results showed that the catalyst Sn/zeolite was dominated by modernit and quartz. XRF analysis results was increasing amount of Sn metal and the Si/Al ratio on Sn/zeolite catalyst along with addition of Sn metal. FTIR analysis results showed that the catalyst synthesized had Bronsted acid side (the spectrum 1639.4; 1656.7; 1654.8 cm-1) and the Lewis acid (spectrum 1400.2 and 1402.2 cm-1). The results showed that the optimum conditions of esterification reaction in 4 hours reaction time, 5% concentration of the catalyst, and molar ratio was about 1:10 with a conversion percentage of products reached 96.00%, which can be achieved with a ratio was about 4:1 between Sn and zeolite on Sn/zeolite catalyst.

Tin Oxynitride Anodes by Atomic Layer Deposition for Solid-State Batteries

DOE PAGES

Stewart, David M.; Pearse, Alexander J.; Kim, Nam S.; ...

2018-03-30

Major advances in thin-film solid-state batteries (TFSSBs) may capitalize on 3D structuring using high-aspect-ratio substrates such as nanoscale pits, pores, trenches, flexible polymers, and textiles. This will require conformal processes such as atomic layer deposition (ALD) for every active functional component of the battery. In this paper, we explore the deposition and electrochemical properties of SnO 2, SnN y, and SnO xN y thin films as TFSSB anode materials, grown by ALD using tetrakisdimethylamido(tin), H 2O, and N 2 plasma as precursors. By controlling the dose ratio between H 2O and N 2, the N–O fraction can be tuned betweenmore » 0% N and 95% N. The electrochemical properties of these materials were tested across a composition range varying from pure SnO 2, to SnON intermediates, and pure SnNy. In TFSSBs, the SnNy anodes are found to be more stable during cycling than the SnO 2 or SnO xN y films, with an initial reversible capacity beyond that of Li–Sn alloying, retaining 75% of their capacity over 200 cycles compared to only 50% for SnO 2. Lastly, the performance of the SnO xN y anodes indicates that SnN y anodes should not be negatively impacted by small levels of O contamination.« less

An ultraviolet spectrophotometric assay for the screening of sn-2-specific lipases using 1,3-O-dioleoyl-2-O-α-eleostearoyl-sn-glycerol as substrate

PubMed Central

Mendoza, Lilia D.; Rodriguez, Jorge A.; Leclaire, Julien; Buono, Gerard; Fotiadu, Frédéric; Carrière, Frédéric; Abousalham, Abdelkarim

2012-01-01

In the present study, we propose a continuous assay for the screening of sn-2 lipases by using triacylglycerols (TAGs) from Aleurites fordii seed (tung oil) and a synthetic TAG containing the α-eleostearic acid at the sn-2 position and the oleic acid (OA) at the sn-1 and sn-3 positions [1,3-O-dioleoyl-2-O-α-eleostearoyl-sn-glycerol (sn-OEO)]. Each TAG was coated into a microplate well, and the lipase activity was measured by optical density increase at 272 nm due to transition of α-eleostearic acid from the adsorbed to the soluble state. The sn-1,3-regioselective lipases human pancreatic lipase (HPL), LIP2 lipase from Yarrowia lipolytica (YLLIP2), and a known sn-2 lipase, Candida antarctica lipase A (CALA) were used to validate this method. TLC analysis of lipolysis products showed that the lipases tested were able to hydrolyze the sn-OEO and the tung oil TAGs, but only CALA hydrolyzed the sn-2 position. The ratio of initial velocities on sn-OEO and tung oil TAGs was used to estimate the sn-2 preference of lipases. CALA was the enzyme with the highest ratio (0.22 ± 0.015), whereas HPL and YLLIP2 showed much lower ratios (0.072 ± 0.026 and 0.038 ± 0.016, respectively). This continuous sn-2 lipase assay is compatible with a high sample throughput and thus can be applied to the screening of sn-2 lipases. PMID:22114038

Study of Diffusion Barrier for Solder/ n-Type Bi2Te3 and Bonding Strength for p- and n-Type Thermoelectric Modules

NASA Astrophysics Data System (ADS)

Lin, Wen-Chih; Li, Ying-Sih; Wu, Albert T.

2018-01-01

This paper investigates the interfacial reaction between Sn and Sn3Ag0.5Cu (SAC305) solder on n-type Bi2Te3 thermoelectric material. An electroless Ni-P layer successfully suppressed the formation of porous SnTe intermetallic compound at the interface. The formation of the layers between Bi2Te3 and Ni-P indicates that Te is the dominant diffusing species. Shear tests were conducted on both Sn and SAC305 solder on n- and p-type Bi2Te3 with and without a Ni-P barrier layer. Without a Ni-P layer, porous SnTe would result in a more brittle fracture. A comparison of joint strength for n- and p-type thermoelectric modules is evaluated by the shear test. Adding a diffusion barrier increases the mechanical strength by 19.4% in n-type and 74.0% in p-type thermoelectric modules.

Treatment response of airway clearance assessed by single-breath washout in children with cystic fibrosis.

PubMed

Abbas, Chiara; Singer, Florian; Yammine, Sophie; Casaulta, Carmen; Latzin, Philipp

2013-12-01

We studied the ability of 4 single-breath gas washout (SBW) tests to measure immediate effects of airway clearance in children with CF. 25 children aged 4-16 years with CF performed pulmonary function tests to assess short-term variability at baseline and response to routine airway clearance. Tidal helium and sulfur hexafluoride (double-tracer gas: DTG) SBW, tidal capnography, tidal and vital capacity nitrogen (N2) SBW and spirometry were applied. We analyzed the gasses' phase III slope (SnIII--normalized for tidal volume) and FEV1 from spirometry. SnIII from tidal DTG-SBW, SnIII from vital capacity N2-SBW, and FEV1 improved significantly after airway clearance. From these tests, individual change of SnIII from tidal DTG-SBW and FEV1 exceeded short-term variability in 10 and 6 children. With the tidal DTG-SBW, an easy and promising test for peripheral gas mixing efficiency, immediate pulmonary function response to airway clearance can be assessed in CF children. Copyright © 2013 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Tin Whisker Growth and Mitigation with a Nanocrysytalline Nickel Coating

NASA Astrophysics Data System (ADS)

Janiuk, Szymon

Tin whiskers are a problem in the electronics industry since the EU banned the use of lead in Pb-Sn solders as part of the Restriction of Hazardous Substances (RoHS). The biggest concern with Sn whiskers is their ability to short-circuit electronics. High reliability applications such as the aerospace, defense, healthcare, and automotive industries are at most risk. This project explores Sn whisker mitigation and prevention with the use of nanocrystalline nickel coating over Sn surfaces. Sn was plated onto a pure Cu substrate using electroplating. A high temperature and high humidity condition, at 85°C and 85% RH, was effective at growing whiskers. A nNi coating was plated over Sn/Cu coupons. After subjecting the nNi/ Sn/Cu samples through 85°C/85% RH testing conditions, no whiskers were observed penetrating the surface. These results make nNi a viable material to use as a coating to prevent the growth of Sn whiskers in electronic assemblies.

Impact of additional sulphur on structure, morphology and optical properties of SnS thin films by thermal evaporation

NASA Astrophysics Data System (ADS)

Banotra, Arun; Padha, Naresh; Kumar, Shiv; Kapoor, Ashok K.

2018-05-01

Thin films of SnS have been obtained from Sn and S powders which were mixed up using ball mill technique with and without evaporating additional sulphur prior to annealing at 523K. The obtained samples were taken for structural, optical, chemical and morphological studies. The X-ray diffraction reveals the formation of SnS phase on annealing in vacuum having S/Sn ratio of 0.67 obtained from EDAX. This deficit in `S' is removed by supplementing additional `S' of 200nm prior to annealing which results in the S/Sn ratio of 1.01. The optical transmission recorded from spectrophotometer used to study different optical parameters. Morphological results corroborate well with the XRD, EDAX and optical study. The obtained stoichiometric films were also tested for Ag/p-SnS Schottky diodes on In coated glass substrates using current voltage measurements.

In vitro stereoselective hydrolysis of diacylglycerols by hormone-sensitive lipase.

PubMed

Rodriguez, Jorge A; Ben Ali, Yassine; Abdelkafi, Slim; Mendoza, Lilia D; Leclaire, Julien; Fotiadu, Frédéric; Buono, Gerard; Carrière, Frédéric; Abousalham, Abdelkarim

2010-01-01

Hormone-sensitive lipase (HSL) contributes importantly to the mobilization of fatty acids in adipocytes and shows a substrate preference for the diacylglycerols (DAGs) originating from triacylglycerols. To determine whether HSL shows any stereopreference during the hydrolysis of diacylglycerols, racemic 1,2(2,3)-sn-diolein was used as a substrate and the enantiomeric excess (ee%) of residual 1,2-sn-diolein over 2,3-sn-diolein was measured as a function of DAG hydrolysis. Enantiomeric DAGs were separated by performing chiral-stationary-phase HPLC after direct derivatization from lipolysis product extracts. The fact that the ee% of 1,2-sn-diolein over 2,3-sn-diolein increased with the level of hydrolysis indicated that HSL has a preference for 2,3-sn-diolein as a substrate and therefore a stereopreference for the sn-3 position of dioleoylglycerol. The ee% of 1,2-sn-diolein reached a maximum value of 36% at 42% hydrolysis. Among the various mammalian lipases tested so far, HSL is the only lipolytic carboxylester hydrolase found to have a pronounced stereospecificity for the sn-3 position of dioleoylglycerol.

Platinum-tin catalysts supported on silica highly selective for n-hexane dehydrogenation

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

Llorca, J.; Homs, N.; Sales, J.

Silica-supported Pt-Sn catalysts were prepared by two-step impregnation from [PtCl{sub 2}(PPh{sub 3}){sub 2}] and SnCl{sub 2} solutions of appropriate concentrations to yield Pt/Sn atomic ratios ranging from 0.2 to 5.0. In these systems, the presence of true Pt-Sn alloys was confirmed by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray analysis and electron nanodiffraction. Pt and PtSn alloy phases were found on catalysts with Pt/Sn > 1, PtSn alloy alone on the catalyst with Pt/Sn = 1 and PtSn and PtSn{sub 2} alloys, together with Sn in the catalysts with Pt/Sn < 1. All these catalysts were tested in themore » skeletal reactions of n-hexane at 753 K and atmospheric pressure. The selectivity of Pt changed significantly when alloyed with tin. For Sn-rich compositions a segregation of tin toward the catalyst surface was shown by photoelectron spectroscopy, and high hydrogenolysis selectivity and fast deactivation were observed. In contrast, Pt-rich catalysts, in which a well defined PtSn alloy was observed, were much more stable and exhibited high selectivity to dehydrogenation reaction while maintaining low conversions to benzene and hydrogenolysis products. This selectivity pattern can be interpreted in terms of a change in adsorption properties due to differences in the number of adjacent Pt atoms required for the various reaction pathways. 24 refs., 11 figs., 3 tabs.« less

Solid cryogen: a cooling system for future MgB2 MRI magnet

PubMed Central

Patel, Dipak; Hossain, Md Shahriar Al; Qiu, Wenbin; Jie, Hyunseock; Yamauchi, Yusuke; Maeda, Minoru; Tomsic, Mike; Choi, Seyong; Kim, Jung Ho

2017-01-01

An efficient cooling system and the superconducting magnet are essential components of magnetic resonance imaging (MRI) technology. Herein, we report a solid nitrogen (SN2) cooling system as a valuable cryogenic feature, which is targeted for easy usability and stable operation under unreliable power source conditions, in conjunction with a magnesium diboride (MgB2) superconducting magnet. The rationally designed MgB2/SN2 cooling system was first considered by conducting a finite element analysis simulation, and then a demonstrator coil was empirically tested under the same conditions. In the SN2 cooling system design, a wide temperature distribution on the SN2 chamber was observed due to the low thermal conductivity of the stainless steel components. To overcome this temperature distribution, a copper flange was introduced to enhance the temperature uniformity of the SN2 chamber. In the coil testing, an operating current as high as 200 A was applied at 28 K (below the critical current) without any operating or thermal issues. This work was performed to further the development of SN2 cooled MgB2 superconducting coils for MRI applications. PMID:28251984

Evaluation of Die-Attach Bonding Using High-Frequency Ultrasonic Energy for High-Temperature Application

NASA Astrophysics Data System (ADS)

Lee, Jong-Bum; Aw, Jie-Li; Rhee, Min-Woo

2014-09-01

Room-temperature die-attach bonding using ultrasonic energy was evaluated on Cu/In and Cu/Sn-3Ag metal stacks. The In and Sn-3Ag layers have much lower melting temperatures than the base material (Cu) and can be melted through the heat generated during ultrasonic bonding, forming intermetallic compounds (IMCs). Samples were bonded using different ultrasonic powers, bonding times, and forces and subsequently aged at 300°C for 500 h. After aging, die shear testing was performed and the fracture surfaces were inspected by scanning electron microscopy. Results showed that the shear strength of Cu/In joints reached an upper plateau after 100 h of thermal aging and remained stable with aging time, whereas that of the Cu/Sn-3Ag joints decreased with increasing aging time. η-Cu7In4 and (Cu,Au)11In9 IMCs were observed at the Cu/In joint, while Cu3Sn and (Ag,Cu)3Sn IMCs were found at the Cu/Sn-3Ag joint after reliability testing. As Cu-based IMCs have high melting temperatures, they are highly suitable for use in high-temperature electronics, but can be formed at room temperature using an ultrasonic approach.

Corrosion and Discharge Behaviors of Al-Mg-Sn-Ga-In in Different Solutions

NASA Astrophysics Data System (ADS)

Xiong, Hanqing; Yin, Xiang; Yan, Yang; Dai, Yilong; Fan, Sufeng; Qiao, Xueyan; Yu, Kun

2016-08-01

Al-0.5 wt.%Mg-0.08 wt.%Sn-0.05 wt.%Ga-0.05 wt.%In and Al-0.5 wt.%Mg-0.08 wt.%Sn-0.05 wt.%Ga alloys were prepared by melting, casting and cold rolling. Corrosion and discharge behaviors of the two experimental alloys were investigated by electrochemical measurement, self-corrosion rate measurement, air battery testing, and scanning electron microscopy. The results showed that Al-Mg-Sn-Ga-In alloy exhibited higher electrochemical activity than Al-Mg-Sn-Ga alloy in 2 M NaCl solution, while it showed lower electrochemical activity than Al-Mg-Sn-Ga alloy in 4 M NaOH solution. By comparison with the air battery based on Al-Mg-Sn-Ga alloy, the battery with Al-Mg-Sn-Ga-In alloy cannot exhibit better discharge performance in 4 M NaOH electrolyte. However, the performance of the air battery based on Al-Mg-Sn-Ga-In alloy was greatly improved due to the In-rich inclusions and the uniform corroded morphology in 2 M NaCl electrolyte. Thus, Al-Mg-Sn-Ga-In alloy was a good anode material for Al-air battery in 2 M NaCl electrolyte.

A relativistic neutron fireball from a supernova explosion as a possible source of chiral influence.

PubMed

Gusev, G A; Saito, T; Tsarev, V A; Uryson, A V

2007-06-01

We elaborate on a previously proposed idea that polarized electrons produced from neutrons, released in a supernova (SN) explosion, can cause chiral dissymmetry of molecules in interstellar gas-dust clouds. A specific physical mechanism of a relativistic neutron fireball with Lorentz factor of the order of 100 is assumed for propelling a great number of free neutrons outside the dense SN shell. A relativistic chiral electron-proton plasma, produced from neutron decays, is slowed down owing to collective effects in the interstellar plasma. As collective effects do not involve the particle spin, the electrons can carry their helicities to the cloud. The estimates show high chiral efficiency of such electrons. In addition to this mechanism, production of circularly polarized ultraviolet photons through polarized-electron bremsstrahlung at an early stage of the fireball evolution is considered. It is shown that these photons can escape from the fireball plasma. However, for an average density of neutrals in the interstellar medium of the order of 0.2 cm(-3) and at distances of the order of 10 pc from the SN, these photons will be absorbed with a factor of about 10(-7) due to the photoeffect. In this case, their chiral efficiency will be about five orders of magnitude less than that for polarized electrons.

Photocatalytic performance of Ag doped SnO2 nanoparticles modified with curcumin

NASA Astrophysics Data System (ADS)

Vignesh, K.; Hariharan, R.; Rajarajan, M.; Suganthi, A.

2013-07-01

Visible light active Ag doped SnO2 nanoparticles modified with curcumin (Cur-Ag-SnO2) have been prepared by a combined precipitation and chemical impregnation route. The optical properties, phase structures and morphologies of the as-prepared nanoparticles were characterized using UV-visible diffuse reflectance spectra (UV-vis-DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The surface area was measured by Brunauer. Emmett. Teller (B.E.T) analysis. Compared to bare SnO2, the surface modified photocatalysts (Ag-SnO2 and Cur-Ag-SnO2) showed a red shift in the visible region. The photocatalytic activity was monitored via the degradation of rose bengal (RB) dye and the results revealed that Cur-Ag-SnO2 shows better photocatalytic activity than that of Ag-SnO2 and SnO2. The superior photocatalytic activity of Cur-Ag-SnO2 could be attributed to the effective electron-hole separation by surface modification. The effect of photocatalyst concentration, initial dye concentration and electron scavenger on the photocatalytic activity was examined in detail. Furthermore, the antifungal activity of the photocatalysts and the reusability of Cur-Ag-SnO2 were tested.

Microstructure and Mechanical Properties of Stainless Steel/Brass Joints Brazed by Sn-Electroplated Ag Brazing Filler Metals

NASA Astrophysics Data System (ADS)

Wang, Xingxing; Peng, Jin; Cui, Datian

2018-05-01

To develop a high-Sn-content AgCuZnSn brazing filler metal, the BAg50CuZn was used as the base filler metal and a Sn layer was electroplated upon it. Then, the 304 stainless steel and the H62 brass were induction-brazed with the Sn-plated brazing filler metals. The microstructures of the joints were examined with an optical microscope, a scanning electron microscope and an x-ray diffractometer. The corresponding mechanical properties were obtained with a universal tensile testing machine. The results indicated that the induction brazed joints consisted of the Ag phase, the Cu phase and the CuZn phase. When the content of Sn in the Sn-plated Ag brazing filler metal was 6.0 or 7.2 wt.%, the Cu5Zn8, the Cu41Sn11 and the Ag3Sn phases appeared in the brazed joint. The tensile strength of the joints brazed with the Sn-plated filler metal was higher compared to the joints with the base filler metal. When the content of Sn was 6.0 wt.%, the highest tensile strength of the joint reached to 395 MPa. The joint fractures presented a brittle mode, mixed with a low amount of ductile fracture, when the content of Sn exceeded 6.0 wt.%.

Testing a linear time invariant model for skin conductance responses by intraneural recording and stimulation

PubMed Central

Gerster, Samuel; Namer, Barbara; Elam, Mikael

2017-01-01

Abstract Skin conductance responses (SCR) are increasingly analyzed with model‐based approaches that assume a linear and time‐invariant (LTI) mapping from sudomotor nerve (SN) activity to observed SCR. These LTI assumptions have previously been validated indirectly, by quantifying how much variance in SCR elicited by sensory stimulation is explained under an LTI model. This approach, however, collapses sources of variability in the nervous and effector organ systems. Here, we directly focus on the SN/SCR mapping by harnessing two invasive methods. In an intraneural recording experiment, we simultaneously track SN activity and SCR. This allows assessing the SN/SCR relationship but possibly suffers from interfering activity of non‐SN sympathetic fibers. In an intraneural stimulation experiment under regional anesthesia, such influences are removed. In this stimulation experiment, about 95% of SCR variance is explained under LTI assumptions when stimulation frequency is below 0.6 Hz. At higher frequencies, nonlinearities occur. In the intraneural recording experiment, explained SCR variance is lower, possibly indicating interference from non‐SN fibers, but higher than in our previous indirect tests. We conclude that LTI systems may not only be a useful approximation but in fact a rather accurate description of biophysical reality in the SN/SCR system, under conditions of low baseline activity and sporadic external stimuli. Intraneural stimulation under regional anesthesia is the most sensitive method to address this question. PMID:28862764

Evaluation of Pt Alloys as Electrocatalysts for Oxalic Acid Oxidation: A Combined Experimental and Computational Study

DOE PAGES

Perry, Albert; Babanova, Sofia; Matanovic, Ivana; ...

2016-07-14

Here in this study we combined experimental approaches and density functional theory to evaluate novel platinum-based materials as electrocatalysts for oxalic acid oxidation. Several Pt alloys, PtSn (1:1), PtSn (19:1), PtRu (1:4), PtRuSn (5:4:1), and PtRhSn (3:1:4), were synthetized using sacrificial support method and tested for oxidation of oxalic acid at pH 4. It was shown that PtSn (1:1) and PtRu (1:4) have higher mass activity relative to Pt. These two materials along with Pt and one of the least active alloys, PtSn (19:1), were further analyzed for the oxidation of oxalic acid at different pHs. The results show thatmore » all samples tested followed an identical trend of decreased onset potential with increased pH and increased catalytic activity with decreased pH. Density functional theory was further utilized to gain a fundamental knowledge about the mechanism of oxalic acid oxidation on Pt, PtSn (1:1), and PtRu (1:4). In conclusion, the results of the calculations along with the experimentally observed dependence of generated currents on the oxalic acid concentration indicate that the mechanism of oxalic acid oxidation on Pt proceeds without the participation of surface oxidizing species, while on Pt alloys it involves their participation.« less

Differential immunoglobulin class-mediated responses to components of the U1 small nuclear ribonucleoprotein particle in systemic lupus erythematosus and mixed connective tissue disease.

PubMed

Mesa, A; Somarelli, J A; Wu, W; Martinez, L; Blom, M B; Greidinger, E L; Herrera, R J

2013-11-01

The objective of this paper is to determine whether patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) possess differential IgM- and IgG-specific reactivity against peptides from the U1 small nuclear ribonucleoprotein particle (U1 snRNP). The IgM- and IgG-mediated responses against 15 peptides from subunits of the U1 snRNP were assessed by indirect enzyme linked immunosorbent assays (ELISAs) in sera from patients with SLE and MCTD and healthy individuals (n = 81, 41, and 31, respectively). Additionally, 42 laboratory tests and 40 clinical symptoms were evaluated to uncover potential differences. Binomial logistic regression analyses (BLR) were performed to construct models to support the independent nature of SLE and MCTD. Receiver operating characteristic (ROC) curves corroborated the classification power of the models. We analyzed IgM and IgG anti-U1 snRNP titers to classify SLE and MCTD patients. IgG anti-U1 snRNP reactivity segregates SLE and MCTD from nondisease controls with an accuracy of 94.1% while IgM-specific anti-U1 snRNP responses distinguish SLE from MCTD patients with an accuracy of 71.3%. Comparison of the IgG and IgM anti-U1 snRNP approach with clinical tests used for diagnosing SLE and MCTD revealed that our method is the best classification tool of those analyzed (p ≤ 0.0001). Our IgM anti-U1 snRNP system along with lab tests and symptoms provide additional molecular and clinical evidence to support the hypothesis that SLE and MCTD may be distinct syndromes.

Observations of the Lyman series forest towards the redshift 7.1 quasar ULAS J1120+0641

NASA Astrophysics Data System (ADS)

Barnett, R.; Warren, S. J.; Becker, G. D.; Mortlock, D. J.; Hewett, P. C.; McMahon, R. G.; Simpson, C.; Venemans, B. P.

2017-05-01

We present a 30 h integration Very Large Telescope X-shooter spectrum of the Lyman series forest towards the z = 7.084 quasar ULAS J1120+0641. The only detected transmission at S/N > 5 is confined to seven narrow spikes in the Lyα forest, over the redshift range 5.858 5.5. The data nevertheless provide only a weak limit on the volume-weighted intergalactic medium (IGM) hydrogen neutral fraction at z 6.5, xH I > 10-4, similar to limits at redshift z 6 from less distant quasars. The new observations cannot extend measurements of the neutral fraction of the IGM to higher values because absorption in the Lyα forest is already saturated near z 6. For higher neutral fractions, other methods such as measuring the red damping wing of the IGM will be required.

Formaldehyde and methanol formation from reaction of carbon monoxide and hydrogen on neutral Fe2S2 clusters in the gas phase.

PubMed

Yin, Shi; Wang, Zhechen; Bernstein, Elliot R

2013-04-07

Reaction of CO with H2 on neutral FemSn clusters in a fast flow reactor is investigated both experimentally and theoretically. Single photon ionization at 118 nm is used to detect neutral cluster distributions through time of flight mass spectrometry. FemSn clusters are generated through laser ablation of a mixed iron-sulfur target in the presence of a pure helium carrier gas. A strong size dependent reactivity of (FeS)m clusters toward CO is characterized. The reaction FeS + CO → Fe + OCS is found for the FeS cluster, and the association product Fe2S2CO is observed for the Fe2S2 cluster. Products Fe2S2(13)COH2 and Fe2S2(13)COH4 are identified for reactions of (13)CO and H2 on Fe2S2 clusters: this suggests that the Fe2S2 cluster has a high catalytic activity for hydrogenation reactions of CO to form formaldehyde and methanol. Density functional theory (DFT) calculations are performed to explore the potential energy surfaces for the two reactions: Fe2S2 + CO + 2H2 → Fe2S2 + CH3OH; and Fe2S2 + CO + H2 → Fe2S2 + CH2O. A barrierless, thermodynamically favorable pathway is obtained for both catalytic processes. Catalytic cycles for formaldehyde and methanol formation from CO and H2 on a Fe2S2 cluster are proposed based on our experimental and theoretical investigations. The various reaction mechanisms explored by DFT are in good agreement with the experimental results. Condensed phase iron sulfide, which contains exposed Fe2S2 units on its surface, is suggested to be a good catalyst for low temperature formaldehyde/methanol synthesis.

Nuclear isomerism in 100Sn neighbors

NASA Astrophysics Data System (ADS)

Ishii, M.; Ishii, T.; Makishima, A.; Ogawa, M.; Momoki, G.; Ogawa, K.

1995-01-01

Data on B(E2), B(M1) and B(E1) were obtained from lifetime measurements in 103, 105, 107In, 105-108Sn and 109Sb. These data helped us to assign the nuclear configurations to the involved states. The experimental B(E2) and B(M1) values in the Sn isotopes worked as litmus paper to test the wave functions calculated on the basis of the shell model. The present calculation gave a qualitative description of M1 transitions in the Sn isotopes but has not yet succeeded in quantitative estimation of B(M1). Calculated B(E2) values were far from the reality since 100Sn was assumed there to be inert against excitation.

A novel snowflake-like SnO2 hierarchical architecture with superior gas sensing properties

NASA Astrophysics Data System (ADS)

Li, Yanqiong

2018-02-01

Snowflake-like SnO2 hierarchical architecture has been synthesized via a facile hydrothermal method and followed by calcination. The SnO2 hierarchical structures are assembled with thin nanoflakes blocks, which look like snowflake shape. A possible mechanism for the formation of the SnO2 hierarchical structures is speculated. Moreover, gas sensing tests show that the sensor based on snowflake-like SnO2 architectures exhibited excellent gas sensing properties. The enhancement may be attributed to its unique structures, in which the porous feature on the snowflake surface could further increase the active surface area of the materials and provide facile pathways for the target gas.

Bluetongue virus surveillance in the Islamic Republic of Mauritania: Is serotype 26 circulating among cattle and dromedaries?

PubMed

Lorusso, Alessio; Baba, Doumbia; Spedicato, Massimo; Teodori, Liana; Bonfini, Barbara; Marcacci, Maurilia; Di Provvido, Andrea; Isselmou, Katia; Marini, Valeria; Carmine, Irene; Scacchia, Massimo; Di Sabatino, Daria; Petrini, Antonio; Bezeid, Beyatt Ahmed; Savini, Giovanni

2016-06-01

In March 2013, EDTA-blood and serum samples were collected from 119 cattle and 159 dromedaries at the slaughterhouse of Nouakchott, the capital city of the Islamic Republic of Mauritania. Serum samples were screened for the presence of Bluetongue (BT) antibodies by competitive ELISA (cELISA). Positive samples were then tested by serum-neutralization (SN) to determine BTV serotype. RNA from blood samples was first tested by a genus-specific quantitative RT-PCR assay which is able to detect all 27 existing BTV serotypes (RT-qPCR1-27). Positive samples were further screened by a RT-qPCR assay which, instead, is able to detect the classical 24 BTV serotypes only (RT-qPCR1-24). Of the 278 serum samples tested, 177 (mean=63.7%; 95% CI: 57.9%-69.1%) resulted positive by cELISA. Of these, 69 were from cattle (mean=58.0%; 95% CI: 49.0%-66.5%) and 108 from dromedaries (mean=67.9%; 95% CI: 60.3%-74.7%). BTV-26 neutralizing antibodies were by far the most frequently found as they were detected in 146 animals with titres ranging from 1:10 to 1:80. Out of 278 blood samples, 25 (mean=9.0%; 95% CI: 6.2%-12.9%) were found positive for BTV by RT-qPCR1-27, 20 (mean=16.8%; 95% CI: 11.2%-24.6%) were from cattle and 5 (mean=3.1%; 95% CI: 1.4%-7.1%) from dromedaries. When tested by RT-qPCR1-24 the 25 BTV positive samples were negative. Unfortunately, no genetic information by molecular typing or by next generation sequencing has been obtained as for the very low levels of RNA in the blood samples. Copyright © 2016 Elsevier B.V. All rights reserved.

LABORATORY OPTIMIZATION TESTS OF TECHNETIUM DECONTAMINATION OF HANFORD WASTE TREATMENT PLANT LOW ACTIVITY WASTE OFF-GAS CONDENSATE SIMULANT

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

Taylor-Pashow, K.; Nash, C.; McCabe, D.

2014-09-29

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrificationmore » mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also compatible with longterm tank storage and immobilization methods. For this new application, testing is needed to demonstrate acceptable treatment sorbents and precipitating agents and measure decontamination factors for additional radionuclides in this unique waste stream. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet and will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. One of the radionuclides that is volatile and expected to be in greatest abundance in this LAW Off-Gas Condensate stream is Technetium-99 ({sup 99}Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are low but are also expected to be in measurable concentration in the LAW Off-Gas Condensate are {sup 129}I, {sup 90}Sr, {sup 137}Cs, {sup 241}Pu, and {sup 241}Am. These are present due to their partial volatility and some entrainment in the off-gas system. This report discusses results of optimized {sup 99}Tc decontamination testing of the simulant. Testing examined use of inorganic reducing agents for {sup 99}Tc. Testing focused on minimizing the quantity of sorbents/reactants added, and minimizing mixing time to reach the decontamination targets in this simulant formulation. Stannous chloride and ferrous sulfate were tested as reducing agents to determine the minimum needed to convert soluble pertechnetate to the insoluble technetium dioxide. The reducing agents were tried with and without sorbents. The sorbents, hydroxyapatite and sodium oxalate, were expected to sorb the precipitated technetium dioxide and facilitate removal. The Phase 1 tests examined a broad range of conditions and used the initial baseline simulant. The Phase 2 tests narrowed the conditions based on Phase 1 results, and used a slightly modified simulant. Test results indicate that excellent removal of {sup 99}Tc was achieved using SnCl{sub 2} as a reductant, and was effective with or without sorption onto hydroxyapatite. This reaction worked even in the presence of air (which could oxidize the stannous ion) and at room temperature. This process was very effective at neutral pH, with a Decontamination Factor (DF) >199 in one hour with only 1 g/L of SnCl{sub 2}. Prior work had shown that it was much less effective at alkaline pH. The only deleterious effect observed was that the chromium co-precipitates with the {sup 99}c during the SnCl{sub 2} reduction. This effect was anticipated, and would have to be considered when managing disposition paths of this stream. Reduction using FeSO{sub 4} was not effective at removing {sup 99}Tc, but did remove the Cr. Chromium is present due to partial volatility and entrainment in the off-gas, and is highly oxidizing, so would be expected to react with reducing agents more quickly than pertechnetate. Testing showed that sufficient reducing agent must be added to completely reduce the chromium before the technetium is reduced and removed. Other radionuclides are also present in this off-gas condensate stream. To enable sending this stream to the Hanford ETF, and thereby divert it from the recycle where it impacts the LAW glass volume, several of these also need to be removed. Samples from optimized conditions were also measured for actinide removal in order to examine the effect of the Tc-removal process on the actinides. Plutonium was also removed by the SnCl{sub 2} precipitation process. Results of this separation testing indicate that sorption/precipitation is a viable concept and has the potential to decontaminate the {sup 99}Tc from the stream, allowing it to be diverted away from WTP and thus eliminating the impact of the recycled halides and sulfate on the LAW glass volume. Based on the results, a possible treatment scenario could involve the use of a reductive precipitation agent (SnCl{sub 2}) with or without sorbent at neutral pH to remove the Tc. Although hydroxyapatite was not necessary to effect the {sup 99}Tc removal, it may be beneficial in solid-liquid separations. Other testing will examine removal of the other radionuclides. This testing was the second phase of testing, which aimed at optimizing the process by examining the minimum amount of reductant needed and the minimum reaction time. Although results indicated that SnCl{sub 2} was effective, further work on a pH-adjusted Fe(SO{sub 4}) mixture are needed. Additional tasks are needed to examine removal of the other radionuclides, solid-liquid separation technologies, slurry rheology measurements, composition variability impacts, corrosion and erosion, and slurry storage and immobilization.« less

Influences of electric current on the wettability and interfacial microstructure in Sn/Fe system

NASA Astrophysics Data System (ADS)

Shen, Ping; Gu, Yan; Yang, Nan-Nan; Zheng, Rui-Peng; Ren, Li-Hua

2015-02-01

The wettability of oxidized and clean Fe substrates by liquid Sn was investigated using a dispensed sessile drop method with and without the application of a direct current (DC) and their interfacial microstructures were compared. The initial contact angles were 107 ± 3° at 623 K when the Fe substrate was covered by an oxide film, and they did not show an appreciable decrease during isothermal dwells in the absence of DC application but progressively decreased to 42 ± 3° when a 7.5 ampere current was applied. However, in the case of the oxide film being removed by a high-vacuum pre-annealing treatment at 1073 K, the current and its polarity had a negligible effect on the wetting behavior. Nevertheless, they had a noticeable influence on the interfacial microstructure. In the absence of DC, the interface was covered by a product layer consisting of a single FeSn2 phase for the samples tested at 623 K and the FeSn2/FeSn2 grain boundaries were incompletely wetted by the Sn melt; whereas, under DC, the reaction layer was much thicker and the Sn melt wet well the FeSn2/FeSn2 grain boundaries. Moreover, a FeSn phase also formed as a result of enhanced mass transfer. The amount of the FeSn phase was larger and the grain boundary wetting of FeSn2 by liquid Sn was better for the current flowing from the molten Sn drop to the Fe substrate due to an electromigration effect.

Comparative analysis of the internalization of the macrophage receptor sialoadhesin in human and mouse primary macrophages and cell lines.

PubMed

De Schryver, Marjorie; Leemans, Annelies; Pintelon, Isabel; Cappoen, Davie; Maes, Louis; Caljon, Guy; Cos, Paul; Delputte, Peter L

2017-06-01

Sialoadhesin (Sn) is a surface receptor expressed on resident macrophages with the ability to bind with sialic acids. During inflammation, an upregulation of Sn is observed. Upon binding of monoclonal antibodies to Sn, the receptor becomes internalized and this has been observed in multiple species. The latter characteristic, combined with the strong upregulation of Sn on inflammatory macrophages and the fact that Sn-positive macrophages contribute to certain inflammatory diseases, makes Sn an interesting entry portal for phenotype-modulating or cytotoxic drugs. Such drugs or toxins can be linked to Sn-specific antibodies which should enable their targeted uptake by macrophages. However, the activity of such drugs depends not only on their internalization but also on the intracellular trafficking and final fate in the endolysosomal system. Although information is available for porcine Sn, the detailed mechanisms of human and mouse Sn internalization and subsequent intracellular trafficking are currently unknown. To allow development of Sn-targeted therapies, differences across species and cellular background need to be characterized in more detail. In the current report, we show that internalization of human and mouse Sn is dynamin-dependent and clathrin-mediated, both in primary macrophages and CHO cell lines expressing a recombinant Sn. In primary macrophages, internalized Sn-specific F(ab') 2 fragments are located mostly in the early endosomes. With Fc containing Sn-specific antibodies, there is a slight shift towards lysosomal localization in mouse macrophages, possibly because of an interaction with Fc receptors. Surprisingly, in CHO cell lines expressing Sn, there is a predominant lysosomal localization. Our results show that the mechanism of Sn internalization and intracellular trafficking is concurrent in the tested species. The cellular background in which Sn is expressed and the type of antibody used can affect the intracellular fate, which in turn can impact the activity of antibody-based therapeutic interventions via Sn. Copyright © 2016 Elsevier GmbH. All rights reserved.

Uncovering the Putative B-Star Binary Companion of the SN 1993J Progenitor

NASA Technical Reports Server (NTRS)

Fox, Ori D.; Bostroem, K. Azalee; Van Dyk, Schuyler D.; Filippenko, Alexei V.; Fransson, Claes; Matheson, Thomas; Cenko, S. Bradley; Chandra, Poonam; Dwarkadas, Vikram; Li, Weidong;

Project W-314 specific test and evaluation plan for transfer line SN-633 (241-AX-B to 241-AY-02A)

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

Hays, W.H.

1998-03-20

The purpose of this Specific Test and Evaluation Plan (STEP) is to provide a detailed written plan for the systematic testing of modifications made by the addition of the SN-633 transfer line by the W-314 Project. The STEP develops the outline for test procedures that verify the system`s performance to the established Project design criteria. The STEP is a lower tier document based on the W-314 Test and Evaluation Plan (TEP). This STEP encompasses all testing activities required to demonstrate compliance to the project design criteria as it relates to the addition of transfer line SN-633. The Project Design Specificationsmore » (PDS) identify the specific testing activities required for the Project. Testing includes Validations and Verifications (e.g., Commercial Grade Item Dedication activities), Factory Acceptance Tests (FATs), installation tests and inspections, Construction Acceptance Tests (CATs), Acceptance Test Procedures (ATPs), Pre-Operational Test Procedures (POTPs), and Operational Test Procedures (OTPs). It should be noted that POTPs are not required for testing of the transfer line addition. The STEP will be utilized in conjunction with the TEP for verification and validation.« less

Highly Sensitive and Selective Hydrogen Gas Sensor Using the Mesoporous SnO₂ Modified Layers.

PubMed

Xue, Niuzi; Zhang, Qinyi; Zhang, Shunping; Zong, Pan; Yang, Feng

2017-10-14

It is important to improve the sensitivities and selectivities of metal oxide semiconductor (MOS) gas sensors when they are used to monitor the state of hydrogen in aerospace industry and electronic field. In this paper, the ordered mesoporous SnO₂ (m-SnO₂) powders were prepared by sol-gel method, and the morphology and structure were characterized by X-ray diffraction analysis (XRD), transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET). The gas sensors were fabricated using m-SnO₂ as the modified layers on the surface of commercial SnO₂ (c-SnO₂) by screen printing technology, and tested for gas sensing towards ethanol, benzene and hydrogen with operating temperatures ranging from 200 °C to 400 °C. Higher sensitivity was achieved by using the modified m-SnO₂ layers on the c-SnO₂ gas sensor, and it was found that the S(c/m2) sensor exhibited the highest response (Ra/Rg = 22.2) to 1000 ppm hydrogen at 400 °C. In this paper, the mechanism of the sensitivity and selectivity improvement of the gas sensors is also discussed.

Revealing Surface States in In-Doped SnTe Nanoplates with Low Bulk Mobility.

PubMed

Shen, Jie; Xie, Yujun; Cha, Judy J

2015-06-10

Indium (In) doping in topological crystalline insulator SnTe induces superconductivity, making In-doped SnTe a candidate for a topological superconductor. SnTe nanostructures offer well-defined nanoscale morphology and high surface-to-volume ratios to enhance surface effects. Here, we study In-doped SnTe nanoplates, In(x)Sn(1-x)Te, with x ranging from 0 to 0.1 and show they superconduct. More importantly, we show that In doping reduces the bulk mobility of In(x)Sn(1-x)Te such that the surface states are revealed in magnetotransport despite the high bulk carrier density. This is manifested by two-dimensional linear magnetoresistance in high magnetic fields, which is independent of temperature up to 10 K. Aging experiments show that the linear magnetoresistance is sensitive to ambient conditions, further confirming its surface origin. We also show that the weak antilocalization observed in In(x)Sn(1-x)Te nanoplates is a bulk effect. Thus, we show that nanostructures and reducing the bulk mobility are effective strategies to reveal the surface states and test for topological superconductors.

Identify and Quantify the Mechanistic Sources of Sensor Performance Variation Between Individual Sensors SN1 and SN2

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

Diaz, Aaron A.; Baldwin, David L.; Cinson, Anthony D.

2014-08-06

This Technical Letter Report satisfies the M3AR-14PN2301022 milestone, and is focused on identifying and quantifying the mechanistic sources of sensor performance variation between individual 22-element, linear phased-array sensor prototypes, SN1 and SN2. This effort constitutes an iterative evolution that supports the longer term goal of producing and demonstrating a pre-manufacturing prototype ultrasonic probe that possesses the fundamental performance characteristics necessary to enable the development of a high-temperature sodium-cooled fast reactor inspection system. The scope of the work for this portion of the PNNL effort conducted in FY14 includes performing a comparative evaluation and assessment of the performance characteristics of themore » SN1 and SN2 22 element PA-UT probes manufactured at PNNL. Key transducer performance parameters, such as sound field dimensions, resolution capabilities, frequency response, and bandwidth are used as a metric for the comparative evaluation and assessment of the SN1 and SN2 engineering test units.« less

The function of Sn(II)-apatite as a Tc immobilizing agent

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

Asmussen, R. Matthew; Neeway, James J.; Lawter, Amanda R.

2016-11-01

Technetium-99 is a radioactive contaminant of high concern at many nuclear waste storage sites. At the U.S. Department of Energy Hanford Site, 99Tc is a component of low-activity waste (LAW) fractions of the nuclear tank waste, which are highly caustic, high ionic strength and have high concentrations of chromate. Removal of 99Tc from LAW streams would greatly benefit the site remediation process. In this study, we investigated the removal of 99Tc(VII), as pertechnetate, from deionized water (DIW) and a LAW simulant using two solid sorbents, tin (II) apatite (Sn-A) and SnCl2 through batch sorption testing and solid phase characterization. Sn-Amore » showed higher levels of removal of Tc from both DIW and LAW simulant compared with the SnCl2. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/XEDS) and X-ray adsorption spectroscopy (XAS) of Sn-A following batch experiments in DIW showed that TcO4- is reduced to Tc(IV) on the Sn-A surface with no incorporation into the lattice structure of Sn-A. The performance of Sn-A in the LAW simulant was lowered due to a combined effect of the high alkalinity, which lead to an increased dissolution of Sn from the Sn-A, and a preference for the reduction of Cr(VI) over Tc(VII).« less

The Spatial and Temporal Variations in High Latitude Cosmic Noise Absorption and Their Relation to Luminous Aurora

DTIC Science & Technology

1963-05-01

extracted is essentially qual- itative in nature. Ideally one should supplement all-sky camera data with those obtained by means of photometers which...oscillating charges do not collide with each other and with neutral molecules, the energy extracted from the wave by ions and electrons is reradiated...collision frequency Sen & Wyller showed that the couplex index of refraction in the generalized theory is given by 2 20± VB2 sn02cS20 n - i c k A+B

Biomechanical Evaluation of Ti-Nb-Sn Alloy Implants with a Low Young’s Modulus

PubMed Central

Takahashi, Kenta; Shiraishi, Naru; Ishiko-Uzuka, Risa; Anada, Takahisa; Suzuki, Osamu; Masumoto, Hiroshi; Sasaki, Keiichi

2015-01-01

Dental implants are widely used and are a predictable treatment in various edentulous cases. Occlusal overload may be causally related to implant bone loss and a loss of integration. Stress concentrations may be diminished using a mechanobiologically integrated implant with bone tissue. The purpose of this study was to investigate the biomechanical behavior, biocompatibility and bioactivity of a Ti-Nb-Sn alloy as a dental implant material. It was compared with cpTi. Cell proliferation and alkaline phosphatase (ALP) activity were quantified. To assess the degree of osseointegration, a push-in test was carried out. Cell proliferation and ALP activity in the cells grown on prepared surfaces were similar for the Ti-Nb-Sn alloy and for cpTi in all the experiments. A comparison between the Ti-Nb-Sn alloy implant and the cpTi implant revealed that no significant difference was apparent for the push-in test values. These results suggest that implants fabricated using Ti-Nb-Sn have a similar biological potential as cpTi and are capable of excellent osseointegration. PMID:25775158

Interpretations of Antibody Responses to Salmonella enterica Serotype Enteritidis gm Flagellin in Poultry Flocks Are Enhanced by a Kinetics-Based Enzyme-Linked Immunosorbent Assay

PubMed Central

McDonough, Patrick L.; Jacobson, Richard H.; Timoney, John F.; Mutalib, Ahmed; Kradel, David C.; Chang, Yung-fu; Shin, Sang J.; Lein, Donald H.; Trock, Susan; Wheeler, Kaye

1998-01-01

Many regulatory and diagnostic programs for the detection of Salmonella enterica serotype Enteritidis infection in commercial poultry flocks have relied on rapid Pullorum agglutination tests to screen birds because of the shared antigens of S. enterica Enteritidis and S. enterica Pullorum and Gallinarum; however, the use of the enzyme-linked immunosorbent assay (ELISA) format affords better analytical sensitivity than crude agglutination tests. In this study, we adapted our earlier conventional indirect ELISA, using gm flagellin as the antigen, to a kinetics-based, computer-controlled ELISA (KELA). The KELA was used to screen for flagellin antibody from three commercial flocks: (i) a large flock involved in a U.S. Department of Agriculture trace back from a human S. enterica Enteritidis foodborne outbreak (n = 3,209), (ii) a flock infected with the endemic S. enterica Enteritidis serotype but which also had multiple other salmonella serotypes (n = 65), and (iii) an S. enterica Pullorum-infected flock (n = 12). The first flock (S. enterica Enteritidis prevalence of 2.45% based on culture) provided a field test of the KELA and allowed the calculation of diagnostic sensitivity (D-Sn) and diagnostic specificity (D-Sp). With a cutoff of 10 (used for screening flocks [i.e., high sensitivity]), the KELA has a D-Sn of 95.2% and a D-Sp of 18.5%; with a cutoff of 140 (used in confirmatory flock testing [i.e., high specificity]), the KELA has a D-Sn of 28.0% and a D-Sp of 99.1%. We found that with a cutoff of 60 (D-Sn = 63.1%; D-Sp = 91.6%), we could eliminate reactions in the KELA caused by other non-S. enterica Enteritidis salmonellae. The KELA was also compared to two commercial rapid Pullorum tests, the Solvay (D-Sn = 94.9%; D-Sp = 55.5%) and the Vineland (D-Sn = 62.0%; D-Sp = 75.3%). PMID:9665965

Interpretations of antibody responses to Salmonella enterica serotype enteritidis gm flagellin in poultry flocks are enhanced by a kinetics-based enzyme-linked immunosorbent assay.

PubMed

McDonough, P L; Jacobson, R H; Timoney, J F; Mutalib, A; Kradel, D C; Chang, Y F; Shin, S J; Lein, D H; Trock, S; Wheeler, K

1998-07-01

Many regulatory and diagnostic programs for the detection of Salmonella enterica serotype Enteritidis infection in commercial poultry flocks have relied on rapid Pullorum agglutination tests to screen birds because of the shared antigens of S. enterica Enteritidis and S. enterica Pullorum and Gallinarum; however, the use of the enzyme-linked immunosorbent assay (ELISA) format affords better analytical sensitivity than crude agglutination tests. In this study, we adapted our earlier conventional indirect ELISA, using gm flagellin as the antigen, to a kinetics-based, computer-controlled ELISA (KELA). The KELA was used to screen for flagellin antibody from three commercial flocks: (i) a large flock involved in a U.S. Department of Agriculture trace back from a human S. enterica Enteritidis foodborne outbreak (n = 3,209), (ii) a flock infected with the endemic S. enterica Enteritidis serotype but which also had multiple other Salmonella serotypes (n = 65), and (iii) an S. enterica Pullorum-infected flock (n = 12). The first flock (S. enterica Enteritidis prevalence of 2.45% based on culture) provided a field test of the KELA and allowed the calculation of diagnostic sensitivity (D-Sn) and diagnostic specificity (D-Sp). With a cutoff of 10 (used for screening flocks [i.e., high sensitivity]), the KELA has a D-Sn of 95.2% and a D-Sp of 18.5%; with a cutoff of 140 (used in confirmatory flock testing [i.e., high specificity]), the KELA has a D-Sn of 28.0% and a D-Sp of 99.1%. We found that with a cutoff of 60 (D-Sn = 63.1%; D-Sp = 91.6%), we could eliminate reactions in the KELA caused by other non-S. enterica Enteritidis salmonellae. The KELA was also compared to two commercial rapid Pullorum tests, the Solvay (D-Sn = 94.9%; D-Sp = 55.5%) and the Vineland (D-Sn = 62.0%; D-Sp = 75.3%).

Template-free fabrication of hierarchical macro/mesoporpous SnS2/TiO2 composite with enhanced photocatalytic degradation of Methyl Orange (MO)

NASA Astrophysics Data System (ADS)

Dai, Gaopeng; Qin, Haiquan; Zhou, Huan; Wang, Wanqiang; Luo, Tianxiong

2018-02-01

Ordered macro/mesoporous SnS2/TiO2 composite was successfully prepared via a template-free aqueous technique using tetrabutyl titanate as the titanium precursor and SnCl4•5H2O as the tin precursor. The photocatalytic activity of SnS2/TiO2 composite was tested by the degradation of Methyl Orange (MO) aqueous solution under irradiation of the simulated sunlight. It was found that SnS2/TiO2 composite displayed an enhanced photocatalytic activity with a 0.055 min-1 apparent rate constant (degradation efficiency of 90.9% within 50 min). The ordered macro/mesoporous structure and SnS2/TiO2 heterostructure were considered to play synergistic effects in its enhanced photocatalytic performance, because the ordered porous structure can improve mass transfer and light capture, and heterostructure between SnS2 and TiO2 can reduce the recombination rate of photogenerated electrons and holes.

Three-dimensional SnO2@TiO2 double-shell nanotubes on carbon cloth as a flexible anode for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zhang, Haifeng; Ren, Weina; Cheng, Chuanwei

2015-07-01

In this study, three-dimensional SnO2@TiO2 double-shell nanotubes on carbon cloth are synthesized by a combination of the hydrothermal method for ZnO nanorods and a subsequent SnO2 and TiO2 thin film coating with atomic layer deposition (ALD). The as-prepared SnO2@TiO2 double-shell nanotubes are further tested as a flexible anode for Li ion batteries. The SnO2@TiO2 double-shell nanotubes/carbon cloth electrode exhibited a high initial discharge capacity (e.g. 778.8 mA h g-1 at a high current density of 780 mA g-1) and good cycling performance, which could be attributed to the 3D double-layer nanotube structure. The interior space of the stable TiO2 hollow tube can accommodate the large internal stress caused by volume expansion of SnO2 and protect SnO2 from pulverization and exfoliation.

The design and testing of a cooling system using mixed solid cryogen for a portable superconducting magnetic energy storage system

NASA Astrophysics Data System (ADS)

Kim, K. L.; Song, J. B.; Choi, J. H.; Kim, S. H.; Y Koh, D.; Seong, K. C.; Chang, H. M.; Lee, H. G.

2010-12-01

A cooling system that uses solid nitrogen (SN2) as an effective heat capacity enhancer was recently introduced to enhance the thermal stability of the HTS SMES. Since SN2 has a large enthalpy with minimal weight, it enables a portable system by increasing the recooling to recooling time period (RRTP). However, contact between the SN2 and HTS SMES magnet can be broken by repeated thermal disturbances (thermal 'dry-out' phenomena). Therefore, it is essential to improve thermal contact to allow full use of the heat capacity of SN2. This study evaluated the effect of using a mixture containing SN2 and a small amount of a liquid cryogen as a cooling system in the HTS SMES system. The performance of the cooling system was evaluated using the mixed cryogen and compared with that of SN2 alone. In addition, the role of liquid neon (Ne) as a heat exchanger between SN2 and the HTS SMES magnet is discussed.

Design of WO3-SnO2 core-shell nanofibers and their enhanced gas sensing performance based on different work function

NASA Astrophysics Data System (ADS)

Li, Feng; Gao, Xing; Wang, Rui; Zhang, Tong

2018-06-01

In this work, core-shell WO3-SnO2 (CS-WS) nanofibers (NFs) have been successfully synthesized via a coaxial electrospinning approach. The structure and morphology characteristics of the resultant products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS). To investigate the sensing mechanism of the CS-WS NFs, sensors based on SnO2 NFs, WO3 NFs, and SnO2-WO3 composite NFs were fabricated respectively, and their gas sensing properties were investigated by using CO, ethanol, toluene, acetone, and ammonia as the test gas. The results indicated that the CS-WS NFs exhibited a good response to ethanol (5.09 at 10 ppm) and short response/recovery time (18.5 s and 282 s) compared with the other test gases. The enhanced ethanol sensing properties of CS-WS NFs compared with those of SnO2 NFs were closely associated with the CS structure and its derivative effect due to the different work function of SnO2 and WO3. The approach proposed in this study may contribute to the realization of more sensitive metal oxide semiconductor (MOS) core-shell heterostructure sensors.

Pt-Richcore/Sn-Richsubsurface/Ptskin Nanocubes As Highly Active and Stable Electrocatalysts for the Ethanol Oxidation Reaction.

PubMed

Rizo, Rubén; Arán-Ais, Rosa M; Padgett, Elliot; Muller, David A; Lázaro, Ma Jesús; Solla-Gullón, José; Feliu, Juan M; Pastor, Elena; Abruña, Héctor D

2018-03-14

Direct ethanol fuel cells are one of the most promising electrochemical energy conversion devices for portable, mobile and stationary power applications. However, more efficient and stable and less expensive electrocatalysts are still required. Interestingly, the electrochemical performance of the electrocatalysts toward the ethanol oxidation reaction can be remarkably enhanced by exploiting the benefits of structural and compositional sensitivity and control. Here, we describe the synthesis, characterization, and electrochemical behavior of cubic Pt-Sn nanoparticles. The electrochemical activity of the cubic Pt-Sn nanoparticles was found to be about three times higher than that obtained with unshaped Pt-Sn nanoparticles and six times higher than that of Pt nanocubes. In addition, stability tests indicated the electrocatalyst preserves its morphology and remains well-dispersed on the carbon support after 5000 potential cycles, while a cubic (pure) Pt catalyst exhibited severe agglomeration of the nanoparticles after a similar stability testing protocol. A detailed analysis of the elemental distribution in the nanoparticles by STEM-EELS indicated that Sn dissolves from the outer part of the shell after potential cycling, forming a ∼0.5 nm Pt skin. This particular atomic composition profile having a Pt-rich core, a Sn-rich subsurface layer, and a Pt-skin surface structure is responsible for the high activity and stability.

Packaging Reliability Effect of ENIG and ENEPIG Surface Finishes in Board Level Thermal Test under Long-Term Aging and Cycling

PubMed Central

Shen, Chaobo; Hai, Zhou; Zhao, Cong; Zhang, Jiawei; Evans, John L.; Bozack, Michael J.; Suhling, Jeffrey C.

2017-01-01

This study illustrates test results and comparative literature data on the influence of isothermal aging and thermal cycling associated with Sn-1.0Ag-0.5Cu (SAC105) and Sn-3.0Ag-0.5Cu (SAC305) ball grid array (BGA) solder joints finished with ENIG and ENEPIG on the board side and ENIG on the package side compared with ImAg plating on both sides. The resulting degradation data suggests that the main concern for 0.4 mm pitch 10 mm package size BGA is package side surface finish, not board side. That is, ENIG performs better than immersion Ag for applications involving long-term isothermal aging. SAC305, with a higher relative fraction of Ag3Sn IMC within the solder, performs better than SAC105. SEM and polarized light microscope analysis show cracks propagated from the corners to the center or even to solder bulk, which eventually causes fatigue failure. Three factors are discussed: IMC, grain structure, and Ag3Sn particle. The continuous growth of Cu-Sn intermetallic compounds (IMC) and grains increase the risk of failure, while Ag3Sn particles seem helpful in blocking the crack propagation. PMID:28772811

Secondary node analysis as an indicator for axillary lymphadenectomy in breast cancer patients.

PubMed

Cremades, Manel; Torres, Mireia; Solà, Montse; Navinés, Jordi; Pascual, Icíar; Mariscal, Antonio; Caballero, Albert; Castellà, Eva; Luna, Miguel Ángel; Julián, Joan Francesc

2017-11-01

Currently, there is no agreement regarding if it would be necessary to perform an axillary lymph node dissection (ALND) in patients who have macrometastases in the sentinel lymph node (SLN). We studied the utility of the secondary node analysis (SN), defined as the following node after the SLN in an anatomical and lymphatic pathway, as a sign of malignant axillary involvement. An observational, retrospective and multicentre study was designed to assess the utility of the SN as a sign of axillary involvement. Among 2273 patients with breast cancer, a valid sample of 283 was obtained representing those who had the SN studied. Main endpoints of our study were: the SLN, the SN and the ALND histological pattern. Sensitivity, specificity and precision of the test were also calculated. SN test, in cases with positive SLN, has a sensitivity of 61.1%, a specificity of 78.7%, a positive predictive value of 45.8% and a negative predictive value of 87.3% with a precision of 74.7%. The study of the SN together with the technique of the SLN allows a more precise staging of the axillary involvement, in patients with breast cancer, than just the SLN technique. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Results from the first single cell Nb 3Sn cavity coatings at JLab

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

Eremeev, Grigory

2015-09-01

Nb 3Sn is a promising superconducting material for SRF applications and has the potential to exceed the limitations of niobium. We have used the recently commissioned Nb 3Sn coating system to investigate Nb 3Sn coatings on several single cell cavities by applying the same coating procedure on several different single cells with different history and pre-coating surface preparation. We report on our findings with four 1.5 GHz CEBAF-shape single cell and one 1.3 GHz ILC-shape single cavities that were coated, inspected, and tested.

Control of Dielectric Constant and Anti-Bacterial Activity of PVA-PEG/x-SnO2 Nanofiber

NASA Astrophysics Data System (ADS)

Diantoro, M.; Sari, L. A.; Istirohah, T.; Kusumawati, A. D.; Nasikhudin; Sunaryono

2018-05-01

Research in the utilization of organic natural materials for electronic devices and for the biological application becoming extensively studied. We report a comprehensive review of the role of SnO2 nanoparticle and the effect of light intensity on toxicity properties, antibacterial activity, microstructure and electrical properties of PVA-PEG nanofiber films. The PVA-PEG/SnO2 nanofiber structure has been successfully fabricated on the ITO-glass substrate. Characterization was performed on samples using FTIR, XRD, SEM, toxicity and antibacterial tests, as well as LCR measurement. The presence of various light intensities has also measured the dielectric constant. The addition of SnO2 nanoparticle influenced the structure of the PVA-PEG/SnO2 nanofiber bonding functional group indicated by the appearance of Sn-O-Sn peaks at 648.08 cm-1 and 958 cm-1 wavenumbers. The addition of SnO2 nanoparticles affects the grain size of SnO2. Addition of SnO2 nanoparticles increases the detected toxicity voltage but is still below the threshold. It means the compound is not toxic, or safe to use in the body. The film lacks the antibacterial power of S. Aurelius. The addition of nanoparticles SnO2 increases the dielectric constant but decreases with increasing frequency of input voltage and the intensity of light employed to PVA-PEG/SnO2 nanofiber. The application of the light intensity reduces the dielectric constant of the PVA-PEG/SnO2 nanofiber in all nanoparticle doping ranges.

Antimicrobial activity and interactions of cationic peptides derived from Galleria mellonella cecropin D-like peptide with model membranes.

PubMed

Oñate-Garzón, José; Manrique-Moreno, Marcela; Trier, Steven; Leidy, Chad; Torres, Rodrigo; Patiño, Edwin

2017-03-01

Antimicrobial peptides are effector molecules of the innate immune system against invading pathogens. The cationic charge in their structures has a strong correlation with antimicrobial activity, being responsible for the initial electrostatic interaction between peptides and the anionic microbial surface. This paper contains evidence that charge modification in the neutral peptide Gm cecropin D-like (WT) improved the antimicrobial activity of the modified peptides. Two cationic peptides derived from WT sequence named as ΔM1 and ΔM2, with net charge of +5 and +9, respectively, showed at least an eightfold increase in their antimicrobial activity in comparison to WT. The mechanism of action of these peptides was investigated using small unilamellar vesicles (SUVs) as model membranes. To study permeabilization effects of the peptides on cell membranes, entrapped calcein liposomes were used and the results showed that all peptides induced calcein release from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) SUVs, whereas in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), POPC/POPG and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE)/POPG SUVs, only ΔM1 and ΔM2 induced a notable permeabilization. In addition, interactions of these peptides with phospholipids at the level of the glycerol backbone and hydrophobic domain were studied through observed changes in generalized polarization and fluorescence anisotropy using probes such as Laurdan and DPH, respectively. The results suggest that peptides slightly ordered the bilayer structure at the level of glycerol backbone and on the hydrophobic core in 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) SUVs, whereas in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/DMPG SUVs, only ΔM1 and ΔM2 peptides increased the order of bilayers. Thus, peptides would be inducing clustering of phospholipids creating phospholipid domains with a higher phase transition temperature.

Silver colloidal nanoparticles: antifungal effect against adhered cells and biofilms of Candida albicans and Candida glabrata.

PubMed

Monteiro, D R; Gorup, L F; Silva, S; Negri, M; de Camargo, E R; Oliveira, R; Barbosa, D B; Henriques, M

2011-08-01

The aim of this study was to evaluate the effect of silver nanoparticles (SN) against Candida albicans and Candida glabrata adhered cells and biofilms. SN (average diameter 5 nm) were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. Minimal inhibitory concentration (MIC) tests were performed for C. albicans (n = 2) and C. glabrata (n = 2) grown in suspension following the Clinical Laboratory Standards Institute microbroth dilution method. SN were applied to adhered cells (2 h) or biofilms (48 h) and after 24 h of contact their effect was assessed by enumeration of colony forming units (CFUs) and quantification of total biomass (by crystal violet staining). The MIC results showed that SN were fungicidal against all strains tested at very low concentrations (0.4-3.3 μg ml(-1)). Furthermore, SN were more effective in reducing biofilm biomass when applied to adhered cells (2 h) than to pre-formed biofilms (48 h), with the exception of C. glabrata ATCC, which in both cases showed a reduction ∼90%. Regarding cell viability, SN were highly effective on adhered C. glabrata and respective biofilms. On C. albicans the effect was not so evident but there was also a reduction in the number of viable biofilm cells. In summary, SN may have the potential to be an effective alternative to conventional antifungal agents for future therapies in Candida-associated denture stomatitis.

A novel strategy for discriminating marine oils by using the positional distribution (sn-1, sn-2, sn-3) of omega-3 polyunsaturated fatty acids in triacylglycerols.

PubMed

Araujo, Pedro; Tilahun, Ephrem; Zeng, Yingxu

2018-05-15

A novel strategy for discriminating genuine and adulterated marine oils is proposed. The strategy consists of i) determining the stereospecific distribution (sn-1, sn-2 and sn-3) of omega 3 polyunsaturated fatty acids (ω-3 PUFA) on the backbone of triacylglycerols by using liquid chromatography tandem mass spectrometry; ii) transforming the qualitative stereospecific information into quantitative data by means of a novel strategy; iii) analyzing the transformed data by principal component analysis. The proposed strategy was tested on pure oils (seal, salmon, cod liver, sandeel, blue whiting, herring), a mixture of blue whiting, herring, sandeel and Norway pout and some intentionally adulterated oils. In addition, some published krill oil data were analyzed to confirm the reliability of the new approach. Copyright © 2018 Elsevier B.V. All rights reserved.

Fluxless eutectic bonding of GaAs-on-Si by using Ag/Sn solder

NASA Astrophysics Data System (ADS)

Eo, Sung-Hwa; Kim, Dae-Seon; Jeong, Ho-Jung; Jang, Jae-Hyung

2013-11-01

Fluxless GaAs-on-Si wafer bonding using Ag/Sn solder was investigated to realize uniform and void-free heterogeneous material integration. The effects of the diffusion barrier, Ag/Sn thickness, and Ar plasma treatment were studied to achieve the optimal fluxless bonding process. Pt on a GaAs wafer and Mo on a Si wafer act as diffusion barriers by preventing the flow of Ag/Sn solder into both the wafers. The bonding strength is closely related to the Ag/Sn thickness and Ar plasma treatment. A shear strength test was carried out to investigate the bonding strength. Under identical bonding conditions, the Ag/Sn thickness was optimized to achieve higher bonding strength and to avoid the formation of voids due to thermal stress. An Ar plasma pretreatment process improved the bonding strength because the Ar plasma removed carbon contaminants and metal-oxide bonds from the metal surface.

Effects of tin on microstructure and mechanical behavior of Inconel 718

NASA Technical Reports Server (NTRS)

Dreshfield, R. L.; Johnson, W. A.; Maurer, G. A.

1984-01-01

Columbium, for which the United States is 100 percent import reliant, is of strategic importance to the U.S. aerospace industry. A major amount of the Cb is used in Inconel 718. Should Cb sources be disrupted, it may be desired to use a grade of Cb melting stock having greater Sn content then the preferred vacuum rade. Additions of Sn to Inconel 718 were varied from none added to 1 wt %. The Sn additions below 800 ppm had no detrimental effects on 650 C stress rupture behavior; however, 1-wt % Sn severely degraded both life and ductility. Additions of Sn in excess of 200 ppm were slightly detrimental to the 425 C tensile yield strength and ductility. The Sn additions had no effect on the microstructure of Inconel 718 even after stress rupture testing for over 6000 hr at 650 C.

Cyclic performance tests of Sn/MWCNT composite lithium ion battery anodes at different temperatures

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

Tocoglu, U., E-mail: utocoglu@sakarya.edu.tr; Cevher, O.; Akbulut, H.

In this study tin-multi walled carbon nanotube (Sn-MWCNT) lithium ion battery anodes were produced and their electrochemical galvanostatic charge/discharge tests were conducted at various (25 °C, 35 °C, 50 °C) temperatures to determine the cyclic behaviors of anode at different temperatures. Anodes were produced via vacuum filtration and DC magnetron sputtering technique. Tin was sputtered onto buckypapers to form composite structure of anodes. SEM analysis was conducted to determine morphology of buckypapers and Sn-MWCNT composite anodes. Structural and phase analyses were conducted via X-ray diffraction and Raman Spectroscopy technique. CR2016 coin cells were assembled for electrochemical tests. Cyclic voltammetry testmore » were carried out to determine the reversibility of reactions between anodes and reference electrode between 0.01-2.0 V potential window. Galvanostatic charge/discharge tests were performed to determine cycle performance of anodes at different temperatures.« less

Degradation of pesticides with RSDL® (reactive skin decontamination lotion kit) lotion: LC-MS investigation.

PubMed

Fentabil, Messele; Gebremedhin, Mulu; Purdon, J Garfield; Cochrane, Laura; Goldman, Virginia Streusand

2018-09-01

This study examined the degradation of organophosphate (OP) and carbamate pesticides using RSDL ® (Reactive Skin Decontamination Lotion Kit) lotion. Degradation occurs from a nucleophilic substitution (SN) reaction between an ingredient in the RSDL lotion, potassium 2,3-butanedione monoximate (KBDO), with susceptible sites in the pesticides. Evaluation at several molar ratios of KBDO:test articles using liquid chromatography-mass spectrometry (LC-MS) techniques was performed. The OP test articles, parathion, paraoxon, parathion-methyl, paraoxon-methyl and chlorpyrifos were effectively degraded at molar ratios of four and above in less than 6min contact time. Malathion and malaoxon were similarly converted to inactive by-products at molar ratios as low as two in less than 4min. A minimum molar ratio of nine was found to be effective against the carbamate pesticide carbofuran. In the case of aldicarb, complete destruction was achieved at a molar ratio of fifteen and a reaction time of one hour. It is important to note that these studies are based on a direct liquid phase RSDL lotion reaction with the toxic chemicals without the added physical removal decontamination efficacy component provided by the sponge component of the RSDL kit. The RSDL kit is intended to be used to remove or neutralize chemical warfare agents (CWA) and T-2 toxin from the skin. In actual use, the majority of the CWA decontamination occurs through the combined action of the sponge in both removing the chemical from the skin, and in rapidly mixing the chemicals at a high molar ratio of KBDO:CWA within the pores of the sponge to enhance rapid neutralization of the chemical. Copyright © 2017 Elsevier B.V. All rights reserved.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: AMSU-A1 EOS Instrument, (S/N 202) Qualification Level Vibration Tests of August/September 1998, (S/O 565632, OC-417) Plus Addendum A

NASA Technical Reports Server (NTRS)

Heffer, R.

1998-01-01

The purpose of this report is to present a qualification level vibration testing performed on the S/N 202, EOS AMSU-A1 Instrument was vibration tested to qualification levels per the Ref. 1 shop order. The instrument withstood the 8 g sine sweep test, the 7.5 Grms random vibration test, and the 18.75 g sine burst test in each of the three orthogonal axes. Some loss of transmissibility, however, is seen in the lower reflector after Z-axis random vibration. The test sequence was not without incidence. Failure of Channel 7 in the Limited Performance Test (LPT) performed after completion of the 1 st (X-axis) axis vibration sequence, required replacement of the DRO and subsequent re-testing of the instrument. The post-vibration comprehensive performance test (CPT) was successfully run after completion of the three axes of vibration with the replacement component installed in the instrument. Passing the CPT signified the successful completion of the S/N 202 A1 qualification vibration testing.

Nano-structured Platinum-based Catalysts for the Complete Oxidation of Ethylene Glycol and Glycerol

NASA Astrophysics Data System (ADS)

Falase, Akinbayowa

Direct alcohol fuel cells are a viable alternative to the traditional hydrogen PEM fuel cell. Fuel versatility, integration with existing distribution networks, and increased safety when handling these fuels increases their appeal for portable power applications. In order to maximize their utility, the liquid fuel must be fully oxidized to CO2 so as to harvest the full amount of energy. Methanol and ethanol are widely researched as potential fuels to power these devices, but methanol is a toxic substance, and ethanol has a much lower energy density than other liquids such as gasoline or glucose. Oxidation of complex fuels is difficult to realize, due to difficulty in breaking carbon-carbon bonding and poisoning of the catalysts by oxidative byproducts. In order to achieve the highest efficiency, an anode needs to be engineered in such a way as to maximize activity while minimizing poisoning effects of reaction byproducts. We have engineered an anode that uses platinum-based catalysts that is capable of completely oxidizing ethylene glycol and glycerol in neutral and alkaline media with little evidence of CO poisoning. We have constructed a hybrid anode consisting of a nano-structured PtRu electrocatayst with an NAD-dependent alcohol dehydrogenase for improved oxidation of complex molecules. A nano-structured PtRu catalyst was used to oxidize ethylene glycol and glycerol in neutral media. In situ infrared spectroscopy was used to verify complete oxidation via CO2 generation. There was no evidence of poisoning by CO species. A pH study was performed to determine the effect of pH on oxidative current. The peak currents did not trend at 60 mV/pH unit as would be expected from the Nernst equation, suggesting that adsorption of fuel to the surface of the electrode is not an electron-transfer step. We synthesized nano-structured PtRu, PtSn, and PtRuSn catalysts for oxidation of ethylene glycol and glycerol in alkaline media. The PtRu electrocatalyst the highest oxidative currents and highest stability compared to a nano-structured platinum, PtSn, and PtRuSn catalyst. In situ infrared spectroscopy showed complete oxidation of each fuel occurred by the presence of CO 2, with very little poisoning CO species present. In order to increase oxidative performance in neutral media, a hybrid anode based on nano-structured PtRu and a NAD-dependent alcohol dehydrogenase for the oxidation of ethanol and ethylene glycol was developed. Steady state polarization showed that the hybrid anode had higher current densities than the enzyme or the PtRu electrocatalyst alone. The hybrid anode had higher current densities at concentrations up to 3 M while oxidizing ethanol and ethylene glycol. The catalyst synthesis, characterization, and experimental results demonstrate the feasibility of fuel cells that can oxidize higher order fuels that platinum based catalysts or enzymes cannot oxidize alone. The cooperative mechanism from co-catalysis using inorganic and organic catalysts will allow for deep oxidation and improved power generation.

Synthesis of scaly Sn3O4/TiO2 nanobelt heterostructures for enhanced UV-visible light photocatalytic activity

NASA Astrophysics Data System (ADS)

Chen, Guohui; Ji, Shaozheng; Sang, Yuanhua; Chang, Sujie; Wang, Yana; Hao, Pin; Claverie, Jerome; Liu, Hong; Yu, Guangwei

2015-02-01

A novel scaly Sn3O4/TiO2 nanobelt heterostructured photocatalyst was fabricated via a facile hydrothermal route. The scaly Sn3O4 nanoflakes can be synthesized in situ and assembled on surface coarsened TiO2 nanobelts through a hydrothermal process. The morphology and distribution of Sn3O4 nanoflakes can be well-controlled by simply tuning the Sn/Ti molar ratio of the reactants. Compared with single phase nanostructures of Sn3O4 and TiO2, the scaly hybrid nanobelts exhibited markedly enhanced photoelectrochemical (PEC) response, which caused higher photocatalytic hydrogen evolution even without the assistance of Pt as a co-catalyst, and enhanced the degradation ability of organic pollutants under both UV and visible light irradiation. In addition to the increased exposure of active facets and broad light absorption, the outstanding performance is ascribed to the matching energy band structure between Sn3O4 and TiO2 at the two sides of the heterostructure, which efficiently reduces the recombination of photo-excited electron-hole pairs and prolongs the lifetime of charge carriers. Both photocatalytic assessment and PEC tests revealed that Sn3O4/TiO2 heterostructures with a molar ratio of Sn/Ti of 2/1 exhibited the highest photocatalytic activity. This study provides a facile and low-cost method for the large scale production of Sn3O4 based materials in various applications.A novel scaly Sn3O4/TiO2 nanobelt heterostructured photocatalyst was fabricated via a facile hydrothermal route. The scaly Sn3O4 nanoflakes can be synthesized in situ and assembled on surface coarsened TiO2 nanobelts through a hydrothermal process. The morphology and distribution of Sn3O4 nanoflakes can be well-controlled by simply tuning the Sn/Ti molar ratio of the reactants. Compared with single phase nanostructures of Sn3O4 and TiO2, the scaly hybrid nanobelts exhibited markedly enhanced photoelectrochemical (PEC) response, which caused higher photocatalytic hydrogen evolution even without the assistance of Pt as a co-catalyst, and enhanced the degradation ability of organic pollutants under both UV and visible light irradiation. In addition to the increased exposure of active facets and broad light absorption, the outstanding performance is ascribed to the matching energy band structure between Sn3O4 and TiO2 at the two sides of the heterostructure, which efficiently reduces the recombination of photo-excited electron-hole pairs and prolongs the lifetime of charge carriers. Both photocatalytic assessment and PEC tests revealed that Sn3O4/TiO2 heterostructures with a molar ratio of Sn/Ti of 2/1 exhibited the highest photocatalytic activity. This study provides a facile and low-cost method for the large scale production of Sn3O4 based materials in various applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05749j

Constitutive Behavior of Mixed Sn-Pb/Sn-3.0Ag-0.5Cu Solder Alloys

NASA Astrophysics Data System (ADS)

Tucker, J. P.; Chan, D. K.; Subbarayan, G.; Handwerker, C. A.

2012-03-01

During the transition from Pb-containing solders to Pb-free solders, joints composed of a mixture of Sn-Pb and Sn-Ag-Cu often result from either mixed assemblies or rework. Comprehensive characterization of the mechanical behavior of these mixed solder alloys resulting in a deformationally complete constitutive description is necessary to predict failure of mixed alloy solder joints. Three alloys with 1 wt.%, 5 wt.%, and 20 wt.% Pb were selected so as to represent reasonable ranges of Pb contamination expected from different 63Sn-37Pb components mixed with Sn-3.0Ag-0.5Cu. Creep and displacement-controlled tests were performed on specially designed assemblies at temperatures of 25°C, 75°C, and 125°C using a double lap shear test setup that ensures a nearly homogeneous state of plastic strain at the joint interface. The observed changes in creep and tensile behavior with Pb additions were related to phase equilibria and microstructure differences observed through differential scanning calorimetric and scanning electron microscopic cross-sectional analysis. As Pb content increased, the steady-state creep strain rates increased, and primary creep decreased. Even 1 wt.% Pb addition was sufficient to induce substantially large creep strains relative to the Sn-3.0Ag-0.5Cu alloy. We describe rate-dependent constitutive models for Pb-contaminated Sn-Ag-Cu solder alloys, ranging from the traditional time-hardening creep model to the viscoplastic Anand model. We illustrate the utility of these constitutive models by examining the inelastic response of a chip-scale package (CSP) under thermomechanical loading through finite-element analysis. The models predict that, as Pb content increases, total inelastic dissipation decreases.

The Effect of a Low Fluoride Delivery System on Bacterial Metabolism.

DTIC Science & Technology

1980-09-01

Fluorides, an4 -Ique mechanisms, slow release delivery, temporary restora- tions, bacterial attachment, Streptococcus mutans , bacterial metabo’ilsm...concentrations of NaF, SnF 4 , Na2SnF6 , TiF 4 , and SnCI2 on altering plaque formation by Streptococcus mutans NCTC 10449. Specific tests were...preparation. Microorganisms, Growth Media, and Growth A streptomycin resistant mutant of Streptococcus mutans NCTC 10449 (Bratthall serotype c) has been

Construction and component testing of TAMU3, a 14 Tesla stress-managed Nb3Sn model dipole

NASA Astrophysics Data System (ADS)

Holik, Eddie Frank, III; Benson, Chris; Blackburn, Raymond; Diaczenko, Nick; Elliott, Timothy; Jaisle, Andrew; McInturff, A.; McIntyre, P.; Sattarov, Akhdiyor

2012-06-01

We report the construction and testing of components of TAMU3, a 14 Tesla Nb3Sn block-coil dipole. A primary goal in developing this model dipole is to test a method of stress management in which Lorentz stress is intercepted within the coil assembly and bypassed so that it cannot accumulate to a level that would cause strain degradation in the superconducting windings. Details of the fabrication, tooling, and results of construction and magnet component testing will be presented.

One-step solvothermal synthesis of carnation flower-like SnS2 as superior electrodes for supercapacitor applications

NASA Astrophysics Data System (ADS)

Mishra, Rajneesh Kumar; Baek, Geun Woo; Kim, Kyuwon; Kwon, Hyuck-In; Jin, Sung Hun

2017-12-01

We report the synthesis of carnation flower-like SnS2 (CF-SnS2) via a one-step solvothermal method for potential application as supercapacitor electrodes in energy storage devices. The structural and morphological properties of CF-SnS2 were characterized by X-ray diffraction, Raman analysis, and field-emission scanning and transmission electron microscopies. X-ray photoelectron spectroscopy and scanning tunneling electron microscopy with color mapping verified the distribution of Sn and S, and depicted the successful formation of SnS2. Electrochemical studies were performed to explore the supercapacitive nature of CF-SnS2. Supercapacitors with CF-SnS2 electrodes delivered excellent cyclic voltammetry performances, superior gravimetric specific capacitances, and high power densities. The evaluated specific capacitance and power density reached ∼524.5 F/g and 12.3 W/kg, respectively, at a current density of 0.08 A/g, and ∼215.9 F/g and 61.4 W/kg, respectively, at a current density of 0.38 A/g. These values are at least two times higher than those previously reported. The long-term cyclic stability was also tested to demonstrate the endurance of the CF-SnS2-based supercapacitor, with a 66% rate retention and galvanostatic charge/discharge reversibility. These electrochemical findings indicate that CF-SnS2 is a promising candidate for electrode materials in supercapacitor applications.

Sol–gel synthesis of SnO{sub 2}–MgO nanoparticles and their photocatalytic activity towards methylene blue degradation

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

Bayal, Nisha; Jeevanandam, P., E-mail: jeevafcy@iitr.ernet.in

2013-10-15

Graphical abstract: - Highlights: • A simple sol–gel method for the synthesis of SnO{sub 2}–MgO nanoparticles is reported. • Band gap of SnO{sub 2} can be tuned by varying the magnesium content in SnO{sub 2}–MgO. • SnO{sub 2}–MgO shows good photocatalytic activity towards degradation of methylene blue. - Abstract: SnO{sub 2}–MgO mixed metal oxide nanoparticles were prepared by a simple sol–gel method. The nanoparticles were characterized by power X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The XRD results indicate the formation of mixed metal oxide nanoparticles and alsomore » a decrease of SnO{sub 2} crystallite size in the mixed metal oxide nanoparticles with increasing magnesium oxide content. The reflectance spectroscopy results show a blue shift of the band gap of SnO{sub 2} in the mixed metal oxide nanoparticles. The photocatalytic activity of the SnO{sub 2}–MgO nanoparticles was tested using the photodegradation of aqueous methylene blue in the presence of sunlight. The results indicate that the mixed metal oxide nanoparticles possess higher efficiency for the photodegradation of methylene blue compared to pure SnO{sub 2} nanoparticles.« less

Common and distinct changes of default mode and salience network in schizophrenia and major depression.

PubMed

Shao, Junming; Meng, Chun; Tahmasian, Masoud; Brandl, Felix; Yang, Qinli; Luo, Guangchun; Luo, Cheng; Yao, Dezhong; Gao, Lianli; Riedl, Valentin; Wohlschläger, Afra; Sorg, Christian

2018-02-19

Brain imaging reveals schizophrenia as a disorder of macroscopic brain networks. In particular, default mode and salience network (DMN, SN) show highly consistent alterations in both interacting brain activity and underlying brain structure. However, the same networks are also altered in major depression. This overlap in network alterations induces the question whether DMN and SN changes are different across both disorders, potentially indicating distinct underlying pathophysiological mechanisms. To address this question, we acquired T1-weighted, diffusion-weighted, and resting-state functional MRI in patients with schizophrenia, patients with major depression, and healthy controls. We measured regional gray matter volume, inter-regional structural and intrinsic functional connectivity of DMN and SN, and compared these measures across groups by generalized Wilcoxon rank tests, while controlling for symptoms and medication. When comparing patients with controls, we found in each patient group SN volume loss, impaired DMN structural connectivity, and aberrant DMN and SN functional connectivity. When comparing patient groups, SN gray matter volume loss and DMN structural connectivity reduction did not differ between groups, but in schizophrenic patients, functional hyperconnectivity between DMN and SN was less in comparison to depressed patients. Results provide evidence for distinct functional hyperconnectivity between DMN and SN in schizophrenia and major depression, while structural changes in DMN and SN were similar. Distinct hyperconnectivity suggests different pathophysiological mechanism underlying aberrant DMN-SN interactions in schizophrenia and depression.

Enhanced Activity and Durability of Nanosized Pt-SnO2/IrO2/CNTs Catalyst for Methanol Electrooxidation.

PubMed

Wang, Hongjuan; Wang, Xiaohui; Zheng, Jiadao; Peng, Feng; Yu, Hao

2015-05-01

Pt-SnO2/IrO2/CNTs anode catalyst for direct methanol fuel cell was designed and prepared with IrO2/CNTs as support for the subsequent immobilization of Pt and SnO2 at the same time. The structure of the catalysts and their catalytic performance in methanol electrooxidation were investigated and the roles of IrO2 and SnO2 in methanol electrooxidation were discussed as well. Results show that Pt-SnO2/IrO2/CNTs catalyst exhibits the best activity and durability for methanol electrooxidation when compared with Pt/CNTs, Pt/IrO2/CNTs and Pt-SnO2/CNTs. According to the results of electrochemical tests and physicochemical characterizations, the enhancements of Pt-SnO2/IrO2/CNTs were attributed to the special properties of IrO2 and SnO2, in which IrO2 mainly increases the methanol oxidation activity and SnO2 mainly improves the CO oxidation ability and durability. Therefore, Pt-SnO2/IrO2/CNTs exhibits excellent performance for methanol oxidation with higher electrocatalytic activity (I(f) of 1054 A g(Pt(-1)) and powerful anti-poisoning ability (the onset potential for CO oxidation of 0.3 V) and outstanding durability (the sustained time t in CP of 617 s), revealing a suitable anode catalyst for DMFCs.

New diorganotin(IV) derivatives of 7-hydroxycoumarin (umbelliferone) and their adducts with 1,10-phenanthroline

NASA Astrophysics Data System (ADS)

Nath, Mala; Jairath, Ruchi; Eng, George; Song, Xueqing; Kumar, Ashok

2005-10-01

New diorganotin(IV) derivatives of the general formula R 2Sn(Umb) 2 (where R = n-Bu, n-Oct and Ph; Umb = umbelliferone anion) have been synthesized either by the reaction of R 2SnO with umbelliferone under azeotropic removel of water or by the reaction of R 2SnCl 2 with sodium salt of umbelliferone. Further, the adducts of the general formula R 2Sn(Umb) 2·phen (where R = n-Bu and n-Oct; phen = 1,10-phenanthroline) have also been synthesized by the interaction of R 2Sn(Umb) 2 with 1,10-phenanthroline. The bonding and coordination behavior in these derivatives are discussed on the basis of IR and 119Sn Mössbauer spectroscopic studies in solid state. Their coordination behavior in solution is discussed by the multinuclear ( 1H, 13C and 119Sn) NMR spectral studies. The Mössbauer and IR studies indicate that umbelliferone acts as a monoanionic bidentate ligand in R 2Sn(Umb) 2 coordinating through O(7) and O(1). A distorted octahedral geometry around tin has been proposed for R 2Sn(Umb) 2 as well as for R 2Sn(Umb) 2·phen in solid state. The newly synthesized derivatives have been tested for their anti-inflammatory and cardiovascular activities. The average LD 50 value >1000 mg kg -1 of these compounds indicates their safety margin.

The nucleation and growth mechanism of Ni-Sn eutectic in a single crystal superalloy

NASA Astrophysics Data System (ADS)

Jiang, Weiguo; Wang, Li; Li, Xiangwei; Lou, Langhong

2017-12-01

The microstructure of single crystal superalloy with and without tin layer on the surface of as-cast and heat-treatment state was investigated by optical microscope (OM) and scanning electron microscopy (SEM). The composition of different regions on the surface was tested by energy dispersive X-ray (EDS). The reaction intermetallic compound (IMC) formed in the heat treatment process was confirmed by X-ray diffraction (XRD). The orientations of different microstructure in samples as heat treatment state were determined by electron back-scattering diffraction (EBSD) method. The porosity location in the interdendritic region was observed by X-ray computed tomography (XCT). The experiment results showed that the remained Sn on the surface of the superalloy reacted with Ni, and then formed Ni3Sn4 in the as-cast state. Sn enriched by diffusion along the porosity located in the interdendritic region and γ + γ‧ (contain a little of Sn) eutectic and Ni3Sn2 formed in single crystal superalloy during heat treatment, and the recalescence behaviors were found. Ni3Sn2 nucleated independently in the cooled liquid at the front of (γ + γ‧) (Sn) eutectic. The nucleation and growth mechanism of the eutectic and Ni3Sn2 IMC during heat treatment was discussed in the present paper.

Host Galaxy Spectra of Stripped SN from the Palomar Transient Factory: SN Progenitor Diagnostics and the SN-GRB Connection

NASA Astrophysics Data System (ADS)

Modjaz, Maryam; Gal-Yam, Avishay; Arcavi, Iair

2012-02-01

Stripped core-collapse supernovae (Stripped SNe) are powerful cosmic engines that energize and enrich the ISM and that sometimes accompany GRBs, but the exact mass and metallicity range of their massive progenitors is not known, nor the detailed physics of the explosion. We propose to continue conducting the first uniform and statistically significant study of host galaxies of 60 stripped SNe from the same innovative, homogeneous and galaxy-unbiased survey Palomar Transient Factory in order to determine the environmental conditions that influence the various kinds of massive stellar deaths. By obtaining spectra of the immediate host environments of our sample of stripped SN, we will (1) measure local abundances in order to differentiate between the two progenitor scenarios for stripped SN and (2) derive stellar population ages, masses and star formation histories via detailed stellar population synthesis models. Moreover, we will test if natal chemical abundance has effects on basic SN characteristics, such as peak luminosity. Any observed trends will have ramifications on SN and GRB explosion models and imply important demographic SN considerations. Our dataset will provide a crucial complimentary set to host galaxy studies of long-duration GRBs and pave the way for host studies of transients and SN found via upcoming surveys such as LSST.

Band offset and electron affinity of MBE-grown SnSe2

NASA Astrophysics Data System (ADS)

Zhang, Qin; Li, Mingda Oscar; Lochocki, Edward B.; Vishwanath, Suresh; Liu, Xinyu; Yan, Rusen; Lien, Huai-Hsun; Dobrowolska, Malgorzata; Furdyna, Jacek; Shen, Kyle M.; Cheng, Guangjun; Hight Walker, Angela R.; Gundlach, David J.; Xing, Huili G.; Nguyen, N. V.

2018-01-01

SnSe2 is currently considered a potential two-dimensional material that can form a near-broken gap heterojunction in a tunnel field-effect transistor due to its large electron affinity which is experimentally confirmed in this letter. With the results from internal photoemission and angle-resolved photoemission spectroscopy performed on Al/Al2O3/SnSe2/GaAs and SnSe2/GaAs test structures where SnSe2 is grown on GaAs by molecular beam epitaxy, we ascertain a (5.2 ± 0.1) eV electron affinity of SnSe2. The band offset from the SnSe2 Fermi level to the Al2O3 conduction band minimum is found to be (3.3 ± 0.05) eV and SnSe2 is seen to have a high level of intrinsic electron (n-type) doping with the Fermi level positioned at about 0.2 eV above its conduction band minimum. It is concluded that the electron affinity of SnSe2 is larger than that of most semiconductors and can be combined with other appropriate semiconductors to form near broken-gap heterojunctions for the tunnel field-effect transistor that can potentially achieve high on-currents.

[Evaluation of green indocyanine interest compared to Technetium in sentinel lymph node detection in breast cancer].

PubMed

Guenane, Y; Gorj, M; Nguyen, V; Revol, M; Mazouz-Dorval, S

2016-12-01

Axillary sentinel lymph node (SN) biopsy by using indocyanine green (ICG) fluorescence for breast cancer is a recent technique. However, compared to Technetium-99m (Tc), which is the reference technique, its efficiency has received little testing. Between December 2013 and January 2014, 40 patients with node-negative breast cancer underwent SN biopsy by injecting sub areolar Tc in preoperative stage and injecting sub areolar ICG in intraoperative stage. SN were previously identified and resected by using ICG coupled with infrared camera. After resection of fluorescent SN, we check its radioactivity with a gamma probe (isotopic method). In case of residual radioactive labeling in the axillary crease, we remove the remaining SN. We have retrospectively analyzed the SN detection concordance rates of these two methods. In total we resected 53 SN, among which 48 (90.6%) were indocyanine green positive and 53 (100%) Tc positive. The remaining 5 SN were all ICG negative and Tc positive. Using ICG has not caused any side effect. SN detection for breast cancer by using ICG fluorescence is a promising, reliable technique which nonetheless requires a degree of expertise before reaching similar results as the Tc technique. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Effects of CuZnAl Particles on Properties and Microstructure of Sn-58Bi Solder

PubMed Central

Yang, Fan; Zhang, Liang; Liu, Zhi-quan; Zhong, Su Juan; Ma, Jia; Bao, Li

2017-01-01

With the purpose of improving the properties of the Sn-58Bi lead-free solder, micro-CuZnAl particles ranging from 0 to 0.4 wt % were added into the low temperature eutectic Sn-58Bi lead-free solder. After the experimental testing of micro-CuZnAl particles on the properties and microstructure of the Sn-58Bi solders, it was found that the wettability of the Sn-58Bi solders was obviously improved with addition of CuZnAl particles. When the addition of CuZnAl particles was 0.2 wt %, the wettability of the Sn-58Bi solder performed best. At the same time, excessive addition of CuZnAl particles led to poor wettability. However, the results showed that CuZnAl particles changed the melting point of the Sn-58Bi solder slightly. The microstructure of the Sn-58Bi solder was refined by adding CuZnAl particles. When the content of CuZnAl addition was between 0.1 and 0.2 wt %, the refinement was great. In addition, the interfacial IMC layer between new composite solder and Cu substrate was thinner than that between the Sn-58Bi solder and Cu substrate. PMID:28772917

Wear Behavior and Microstructure of Mg-Sn Alloy Processed by Equal Channel Angular Extrusion

PubMed Central

Chen, Jung-Hsuan; Shen, Yen-Chen; Chao, Chuen-Guang; Liu, Tzeng-Feng

2017-01-01

Mg-5wt.% Sn alloy is often used in portable electronic devices and automobiles. In this study, mechanical properties of Mg-5wt.% Sn alloy processed by Equal Channel Angular Extrusion (ECAE) were characterized. More precisely, its hardness and wear behavior were measured using Vickers hardness test and a pin-on-disc wear test. The microstructures of ECAE-processed Mg-Sn alloys were investigated by scanning electron microscope and X-ray diffraction. ECAE process refined the grain sizes of the Mg-Sn alloy from 117.6 μm (as-cast) to 88.0 μm (one pass), 49.5 μm (two passes) and 24.4 μm (four passes), respectively. Meanwhile, the hardness of the alloy improved significantly. The maximum wear resistance achieved in the present work was around 73.77 m/mm3, which was obtained from the Mg-Sn alloy treated with a one-pass ECAE process with a grain size of 88.0 μm. The wear resistance improvement was caused by the grain size refinement and the precipitate of the second phase, Mg2Sn against the oxidation of the processed alloy. The as-cast Mg-Sn alloy with the larger grain size, i.e., 117.6 μm, underwent wear mechanisms, mainly adhesive wear and abrasive wear. In ECAE-processed Mg-Sn alloy, high internal energy occurred due to the high dislocation density and the stress field produced by the plastic deformation, which led to an increased oxidation rate of the processed alloy during sliding. Therefore, the oxidative wear and a three-body abrasive wear in which the oxide debris acted as the three-body abrasive components became the dominant factors in the wear behavior, and as a result, reduced the wear resistance in the multi-pass ECAE-processed alloy. PMID:29144414

Dark Matter Ignition of Type Ia Supernovae.

PubMed

Bramante, Joseph

2015-10-02

Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of dark matter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting dark matter also resolve the missing pulsar problem by forming black holes in ≳10  Myr old pulsars at the center of the Milky Way.

Development of ultrafine Ti-Fe-Sn in-situ composite with enhanced plasticity

NASA Astrophysics Data System (ADS)

Mondal, B.; Samal, S.; Biswas, K.; Govind

2012-01-01

The present investigation is aimed at developing ultrafine eutectic/dendrite Ti-Fe-Sn in-situ composite with balanced combination of strength and plasticity. It also studies the microstructure evolution in the series of hypereutectic Ti-Fe-Sn ternary alloys. Sn concentration of these alloys has been varied from 0 - 10 atom% in the binary alloy (Ti71Fe29) keeping the Ti concentration fixed. These alloys have been prepared by arc melting under an Ar atmosphere on a water-cooled Cu hearth, which are subsequently suction cast in a split Cu-mold under an Ar atmosphere. Detailed X-ray diffraction (XRD) study shows the presence of TiFe, β-Ti, and Ti3Sn phases. The SEM micrographs reveal that the microstructures consist of fine scale eutectic matrix (β-Ti and TiFe) with primary dendrite phases (TiFe and/or Ti3Sn) depending on concentration of Sn. α -Ti forms as a eutectoid reaction product of β-Ti. The room temperature uniaxial compressive test reveals simultaneous improvement in the strength (1942 MPa) and plasticity (13.1 %) for Ti71Fe26Sn3 ternary alloy. The fracture surface indicates a ductile mode of fracture for the alloy.

Highly Sensitive and Selective Hydrogen Gas Sensor Using the Mesoporous SnO2 Modified Layers

PubMed Central

Xue, Niuzi; Zhang, Qinyi; Zhang, Shunping; Zong, Pan; Yang, Feng

2017-01-01

It is important to improve the sensitivities and selectivities of metal oxide semiconductor (MOS) gas sensors when they are used to monitor the state of hydrogen in aerospace industry and electronic field. In this paper, the ordered mesoporous SnO2 (m-SnO2) powders were prepared by sol-gel method, and the morphology and structure were characterized by X-ray diffraction analysis (XRD), transmission electron microscope (TEM) and Brunauer–Emmett–Teller (BET). The gas sensors were fabricated using m-SnO2 as the modified layers on the surface of commercial SnO2 (c-SnO2) by screen printing technology, and tested for gas sensing towards ethanol, benzene and hydrogen with operating temperatures ranging from 200 °C to 400 °C. Higher sensitivity was achieved by using the modified m-SnO2 layers on the c-SnO2 gas sensor, and it was found that the S(c/m2) sensor exhibited the highest response (Ra/Rg = 22.2) to 1000 ppm hydrogen at 400 °C. In this paper, the mechanism of the sensitivity and selectivity improvement of the gas sensors is also discussed. PMID:29036898

Performance of Al-0.5 Mg-0.02 Ga-0.1 Sn-0.5 Mn as anode for Al-air battery in NaCl solutions

NASA Astrophysics Data System (ADS)

Ma, Jingling; Wen, Jiuba; Gao, Junwei; Li, Quanan

2014-05-01

In this research, metal-air battery based on Al, Zn, Al-0.5 Mg-0.02 Ga-0.1 Sn and Al-0.5 Mg-0.02 Ga-0.1 Sn-0.5 Mn (wt%) is prepared and the battery performance is investigated by constant current discharge test in 2 mol L-1 NaCl solutions. The characteristics of the anodes after discharge are investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM). The corrosion behavior of the anodes is studied by self-corrosion rate measurement and potentiodynamic polarization measurement. The results show that Al-Mg-Ga-Sn-Mn is more active than Al, Zn and Al-Mg-Ga-Sn anodes. The self-corrosion rate is found to be in the order: Al < Al-Mg-Ga-Sn-Mn < Al-Mg-Ga-Sn < Zn. It has been observed that the Al-air battery based on Al-Mg-Ga-Sn-Mn offers higher operating voltage and anodic utilization than those with others. SEM and EIS results of the alloy are in good agreement with corrosion characteristics.

Laser induced forward transfer of SnO2 for sensing applications using different precursors systems

NASA Astrophysics Data System (ADS)

Mattle, Thomas; Hintennach, Andreas; Lippert, Thomas; Wokaun, Alexander

2013-02-01

This paper presents the transfer of SnO2 by laser induced forward transfer (LIFT) for gas sensor applications. Different donor substrates of SnO2 with and without triazene polymer (TP) as a dynamic release layer were prepared. Transferring these films under different conditions were evaluated by optical microscopy and functionality. Transfers of sputtered SnO2 films do not lead to satisfactory results and transfers of SnO2 nanoparticles are difficult. Transfers of SnO2 nanoparticles can only be achieved when applying a second laser pulse to the already transferred material, which improves the adhesion resulting in a complete pixel. A new approach of decomposing the transfer material during LIFT transfer was developed. Donor films based on UV absorbing metal complex precursors namely, SnCl2(acac)2 were prepared and transferred using the LIFT technique. Transfer conditions were optimized for the different systems, which were deposited onto sensor-like microstructures. The conductivity of the transferred material at temperatures of about 400 ∘C are in a range usable for SnO2 gas sensors. First sensing tests were carried out and the transferred material proved to change conductivity when exposed to ethanol, acetone, and methane.

Silage fermentation and ruminal degradation of stylo prepared with lactic acid bacteria and cellulase.

PubMed

Li, Mao; Zhou, Hanlin; Zi, Xuejuan; Cai, Yimin

2017-10-01

In order to improve the silage fermentation of stylo (Stylosanthes guianensis) in tropical areas, stylo silages were prepared with commercial additives Lactobacillus plantarum Chikuso-1 (CH1), L. rhamnasus Snow Lact L (SN), Acremonium cellulase (CE) and their combination as SN+CE or CH1 + CE, and the fermentation quality, chemical composition and ruminal degradation of these silages were studied. Stylo silages treated with lactic acid bacteria (LAB) or cellulase, the pH value and NH 3 -N ⁄ total-N were significantly (P < 0.05) decreased while the ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (aNDFom) and acid detergent fiber (ADFom) were significantly (P < 0.05) increased compared to control. Compared to LAB or cellulase-treated silages, the DM, CP contents and relative feed value (RFV), and the ruminal degradability in LAB plus cellulase-treated silages were significantly (P < 0.05) higher, but the aNDFom content was significantly (P < 0.05) lower. CH1 + CE treatment was more effective in silage fermentation and ruminal degradation than SN+CE treatment. The results confirmed that LAB or LAB plus cellulase treatment could improve the fermentation quality, chemical composition and ruminal degradation of stylo silage. Moreover, the combined treatment with LAB and cellulase may have beneficial synergistic effects on ruminal degradation. © 2017 Japanese Society of Animal Science.

Diagnostic accuracy of clinical tests for assessment of hamstring injury: a systematic review.

PubMed

Reiman, Michael P; Loudon, Janice K; Goode, Adam P

2013-04-01

Systematic literature review. The diagnosis of a hamstring injury has traditionally relied on various clinical measures (eg, palpation, swelling, manual resistance), as well as the use of diagnostic imaging. But a few studies have suggested the use of specific clinical tests that may be helpful for the diagnostic process. To summarize the current literature on the diagnostic accuracy of orthopaedic special tests for hamstring injuries and to determine their clinical utility. A computer-assisted literature search of the MEDLINE, CINAHL, and Embase databases (along with a manual search of grey literature) was conducted using key words related to diagnostic accuracy of hamstring injuries. To be considered for inclusion in the review, the study required (1) patients with hamstring or posterior thigh pain; (2) a cohort, case-control, or cross-sectional design; (3) inclusion of at least 1 clinical examination test used to evaluate hamstring pathology; (4) comparison against an acceptable reference standard; (5) reporting of diagnostic accuracy of the measures (sensitivity [SN], specificity [SP], or likelihood ratios); and (6) publication in English. SN, SP, and positive and negative likelihood ratios were calculated for each diagnostic test. The search strategy identified 602 potential articles, of which only 3 articles met the inclusion criteria, with only 1 of these 3 articles being of high quality. Two of the studies investigated a single special test, whereas the third article examined a composite clinical assessment employing various special tests. The SN values ranged from 0.55 (95% confidence interval [CI]: 0.46, 0.69) for the active range-of-motion test to 1.00 (95% CI: 0.97, 1.00) for the taking-off-the-shoe test. The SP values ranged from 0.03 (95% CI: 0.00, 0.22) for the composite clinical assessment to 1.00 (95% CI: 0.97, 1.00) for the taking-off-the-shoe test, active range-of-motion test, passive range-of-motion test, and resisted range-of-motion test. The use of a single special test demonstrated stronger SP than SN properties, whereas the composite clinical assessment demonstrated stronger SN than SP properties. Very few studies have investigated the utilization of clinical special tests for the diagnosis of hamstring injuries. Further studies of higher quality design are suggested prior to advocating independent clinical utilization of these special tests. Diagnosis, level 3b.

Measurements of Dynamic Effects in FNAL 11 T Nb 3Sn Dipole Models

DOE PAGES

Velev, Gueorgui; Strauss, Thomas; Barzi, Emanuela; ...

2018-01-17

Fermilab, in collaboration with CERN, has developed a twin-aperture 11 T Nb 3Sn dipole suitable for the high-luminosity LHC upgrade. During 2012-2014, a 2-m long single-aperture dipole demonstrator and three 1-m long single-aperture dipole models were fabricated by FNAL and tested at its Vertical Magnet Test Facility. Collared coils from two of the 1-m long models were then used to assemble the first twin-aperture dipole demonstrator. This magnet had extensive testing in 2015-2016, including quench performance, quench protection, and field quality studies. Here, this paper reports the results of measurements of persistent current effects in the single-aperture and twin-aperture 11more » T Nb 3Sn dipoles and compares them with similar measurements in previous NbTi magnets« less

Measurements of Dynamic Effects in FNAL 11 T Nb 3Sn Dipole Models

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

Velev, Gueorgui; Strauss, Thomas; Barzi, Emanuela

Fermilab, in collaboration with CERN, has developed a twin-aperture 11 T Nb 3Sn dipole suitable for the high-luminosity LHC upgrade. During 2012-2014, a 2-m long single-aperture dipole demonstrator and three 1-m long single-aperture dipole models were fabricated by FNAL and tested at its Vertical Magnet Test Facility. Collared coils from two of the 1-m long models were then used to assemble the first twin-aperture dipole demonstrator. This magnet had extensive testing in 2015-2016, including quench performance, quench protection, and field quality studies. Here, this paper reports the results of measurements of persistent current effects in the single-aperture and twin-aperture 11more » T Nb 3Sn dipoles and compares them with similar measurements in previous NbTi magnets« less

Time Resolved Studies of Interfacial Reactions of Ozone with Pulmonary Phospholipid Surfactants Using Field Induced Droplet Ionization Mass Spectrometry

PubMed Central

Kim, Hugh I.; Kim, Hyungjun; Shin, Young Shik; Beegle, Luther W.; Goddard, William A.; Heath, James R.; Kanik, Isik; Beauchamp, J. L.

2013-01-01

Field induced droplet ionization mass spectrometry (FIDI-MS) comprises a soft ionization method to sample ions from the surface of microliter droplets. A pulsed electric field stretches neutral droplets until they develop dual Taylor cones, emitting streams of positively and negatively charged submicrometer droplets in opposite directions, with the desired polarity being directed into a mass spectrometer for analysis. This methodology is employed to study the heterogeneous ozonolysis of 1-palmitoyl-2-oleoyl-sn-phosphatidylglycerol (POPG) at the air–liquid interface in negative ion mode using FIDI mass spectrometry. Our results demonstrate unique characteristics of the heterogeneous reactions at the air–liquid interface. We observe the hydroxyhydroperoxide and the secondary ozonide as major products of POPG ozonolysis in the FIDI-MS spectra. These products are metastable and difficult to observe in the bulk phase, using standard electrospray ionization (ESI) for mass spectrometric analysis. We also present studies of the heterogeneous ozonolysis of a mixture of saturated and unsaturated phospholipids at the air–liquid interface. A mixture of the saturated phospholipid 1,2-dipalmitoyl-sn-phosphatidylglycerol (DPPG) and unsaturated POPG is investigated in negative ion mode using FIDI-MS while a mixture of 1,2-dipalmitoyl-sn-phosphatidylcholine (DPPC) and 1-stearoyl-2-oleoyl-sn-phosphatidylcholine (SOPC) surfactant is studied in positive ion mode. In both cases FIDI-MS shows the saturated and unsaturated pulmonary surfactants form a mixed interfacial layer. Only the unsaturated phospholipid reacts with ozone, forming products that are more hydrophilic than the saturated phospholipid. With extensive ozonolysis only the saturated phospholipid remains at the droplet surface. Combining these experimental observations with the results of computational analysis provides an improved understanding of the interfacial structure and chemistry of a surfactant layer system when subject to oxidative stress. PMID:20608690

Defining the Enterovirus Diversity Landscape of a Fecal Sample: A Methodological Challenge?

PubMed

Faleye, Temitope Oluwasegun Cephas; Adewumi, Moses Olubusuyi; Adeniji, Johnson Adekunle

2016-01-12

Enteroviruses are a group of over 250 naked icosahedral virus serotypes that have been associated with clinical conditions that range from intrauterine enterovirus transmission withfataloutcome through encephalitis and meningitis, to paralysis. Classically, enterovirus detection was done by assaying for the development of the classic enterovirus-specific cytopathic effect in cell culture. Subsequently, the isolates were historically identified by a neutralization assay. More recently, identification has been done by reverse transcriptase-polymerase chain reaction (RT-PCR). However, in recent times, there is a move towards direct detection and identification of enteroviruses from clinical samples using the cell culture-independent RT semi-nested PCR (RT-snPCR) assay. This RT-snPCR procedure amplifies the VP1 gene, which is then sequenced and used for identification. However, while cell culture-based strategies tend to show a preponderance of certain enterovirus species depending on the cell lines included in the isolation protocol, the RT-snPCR strategies tilt in a different direction. Consequently, it is becoming apparent that the diversity observed in certain enterovirus species, e.g., enterovirus species B(EV-B), might not be because they are the most evolutionarily successful. Rather, it might stem from cell line-specific bias accumulated over several years of use of the cell culture-dependent isolation protocols. Furthermore, it might also be a reflection of the impact of the relative genome concentration on the result of pan-enterovirus VP1 RT-snPCR screens used during the identification of cell culture isolates. This review highlights the impact of these two processes on the current diversity landscape of enteroviruses and the need to re-assess enterovirus detection and identification algorithms in a bid to better balance our understanding of the enterovirus diversity landscape.

Defining the Enterovirus Diversity Landscape of a Fecal Sample: A Methodological Challenge?

PubMed Central

Faleye, Temitope Oluwasegun Cephas; Adewumi, Moses Olubusuyi; Adeniji, Johnson Adekunle

2016-01-01

Enteroviruses are a group of over 250 naked icosahedral virus serotypes that have been associated with clinical conditions that range from intrauterine enterovirus transmission withfataloutcome through encephalitis and meningitis, to paralysis. Classically, enterovirus detection was done by assaying for the development of the classic enterovirus-specific cytopathic effect in cell culture. Subsequently, the isolates were historically identified by a neutralization assay. More recently, identification has been done by reverse transcriptase-polymerase chain reaction (RT-PCR). However, in recent times, there is a move towards direct detection and identification of enteroviruses from clinical samples using the cell culture-independent RT semi-nested PCR (RT-snPCR) assay. This RT-snPCR procedure amplifies the VP1 gene, which is then sequenced and used for identification. However, while cell culture-based strategies tend to show a preponderance of certain enterovirus species depending on the cell lines included in the isolation protocol, the RT-snPCR strategies tilt in a different direction. Consequently, it is becoming apparent that the diversity observed in certain enterovirus species, e.g., enterovirus species B(EV-B), might not be because they are the most evolutionarily successful. Rather, it might stem from cell line-specific bias accumulated over several years of use of the cell culture-dependent isolation protocols. Furthermore, it might also be a reflection of the impact of the relative genome concentration on the result of pan-enterovirus VP1 RT-snPCR screens used during the identification of cell culture isolates. This review highlights the impact of these two processes on the current diversity landscape of enteroviruses and the need to re-assess enterovirus detection and identification algorithms in a bid to better balance our understanding of the enterovirus diversity landscape. PMID:26771630

Biophysical implications of sphingosine accumulation in membrane properties at neutral and acidic pH.

PubMed

Zupancic, Eva; Carreira, Ana C; de Almeida, Rodrigo F M; Silva, Liana C

2014-05-08

Sphingosine (Sph) is a simple lipid involved in the regulation of several biological processes. When accumulated in the late endosomal/lysosomal compartments, Sph causes changes in ion signaling and membrane trafficking, leading to the development of Niemann-Pick disease type C. Little is known about Sph interaction with other lipids in biological membranes; however, understanding the effect of Sph in the physical state of membranes might provide insights into its mode of action. Using complementary established fluorescence approaches, we show that Sph accumulation leads to the formation of Sph-enriched gel domains in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and POPC/sphingomyelin (SM)/cholesterol (Chol) model membranes. These domains are more easily formed in membrane models mimicking the neutral pH plasma membrane environment (PM) as compared to the acidic lysosomal membrane environment (LM), where higher Sph concentrations (or lower temperatures) are required. Electrophoretic light scattering measurements further revealed that in PM-raft models (POPC/SM/Chol), Sph is mainly neutral, whereas in LM models, the positive charge of Sph leads to electrostatic repulsion, reducing the Sph ability to form gel domains. Thus, formation of Sph-enriched domains in cellular membranes might be strongly regulated by Sph charge.

Mechanical Deformation Behavior of Sn-Ag-Cu Solders with Minor Addition of 0.05 wt.% Ni

NASA Astrophysics Data System (ADS)

Hammad, A. E.; El-Taher, A. M.

2014-11-01

The aim of the present work is to develop a comparative evaluation of the microstructural and mechanical deformation behavior of Sn-Ag-Cu (SAC) solders with the minor addition of 0.05 wt.% Ni. Test results showed that, by adding 0.05Ni element into SAC solders, generated mainly small rod-shaped (Cu,Ni)6Sn5 intermetallic compounds (IMCs) inside the β-Sn phase. Moreover, increasing the Ag content and adding Ni could result in the change of the shape and size of the IMC precipitate. Hence, a significant improvement is observed in the mechanical properties of SAC solders with increasing Ag content and Ni addition. On the other hand, the tensile results of Ni-doped SAC solders showed that both the yield stress and ultimate tensile strengths decrease with increasing temperature and with decreasing strain rate. This behavior was attributed to the competing effects of work hardening and dynamic recovery processes. The Sn-2.0Ag-0.5Cu-0.05Ni solder displayed the highest mechanical properties due to the formation of hard (Cu,Ni)6Sn5 IMCs. Based on the obtained stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SAC (205)-, SAC (0505)- and SAC (0505)-0.05Ni solders is pipe diffusion, and lattice self-diffusion in SAC (205)-0.05Ni solder. In view of these results, the Sn-2.0Ag-0.5Cu-0.05Ni alloy is a more reliable solder alloy with improved properties compared with other solder alloys tested in the present work.

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

Vardon, Derek R.; Settle, Amy E.; Vorotnikov, Vassili

Succinic acid is a biomass-derived platform chemical that can be catalytically converted in the aqueous phase to 1,4-butanediol (BDO), a prevalent building block used in the polymer and chemical industries. Despite significant interest, limited work has been reported regarding sustained catalyst performance and stability under continuous aqueous-phase process conditions. As such, this work examines Ru-Sn on activated carbon (AC) for the aqueous-phase conversion of succinic acid to BDO under batch and flow reactor conditions. Initially, powder Ru-Sn catalysts were screened to determine the most effective bimetallic ratio and provide a comparison to other monometallic (Pd, Pt, Ru) and bimetallic (Pt-Sn,more » Pd-Re) catalysts. Batch reactor tests determined that a ~1:1 metal weight ratio of Ru to Sn was effective for producing BDO in high yields, with complete conversion resulting in 82% molar yield. Characterization of the fresh Ru-Sn catalyst suggests that the sequential loading method results in Ru sites that are colocated and surface-enriched with Sn. Postbatch reaction characterization confirmed stable Ru-Sn material properties; however, upon a transition to continuous conditions, significant Ru-Sn/AC deactivation occurred due to stainless steel leaching of Ni that resulted in Ru-Sn metal crystallite restructuring to form discrete Ni-Sn sites. Computational modeling confirmed favorable energetics for Ru-Sn segregation and Ni-Sn formation at submonolayer Sn incorporation. To address stainless steel leaching, reactor walls were treated with an inert silica coating by chemical vapor deposition. With leaching reduced, stable Ru-Sn/AC performance was observed that resulted in a molar yield of 71% BDO and 15% tetrahydrofuran for 96 h of time on stream. Postreaction catalyst characterization confirmed low levels of Ni and Cr deposition, although early-stage islanding of Ni-Sn will likely be problematic for industrially relevant time scales (i.e., thousands of hours). Overall, these results (i) demonstrate the performance of Ru-Sn/AC for aqueous phase succinic acid reduction, (ii) provide insight into the Ru-Sn bimetallic structure and deactivation in the presence of leached Ni, and (iii) underscore the importance of compatible reactor metallurgy and durable catalysts.« less

Novel Covariance-Based Neutrality Test of Time-Series Data Reveals Asymmetries in Ecological and Economic Systems

PubMed Central

Burby, Joshua W.; Lacker, Daniel

2016-01-01

Systems as diverse as the interacting species in a community, alleles at a genetic locus, and companies in a market are characterized by competition (over resources, space, capital, etc) and adaptation. Neutral theory, built around the hypothesis that individual performance is independent of group membership, has found utility across the disciplines of ecology, population genetics, and economics, both because of the success of the neutral hypothesis in predicting system properties and because deviations from these predictions provide information about the underlying dynamics. However, most tests of neutrality are weak, based on static system properties such as species-abundance distributions or the number of singletons in a sample. Time-series data provide a window onto a system’s dynamics, and should furnish tests of the neutral hypothesis that are more powerful to detect deviations from neutrality and more informative about to the type of competitive asymmetry that drives the deviation. Here, we present a neutrality test for time-series data. We apply this test to several microbial time-series and financial time-series and find that most of these systems are not neutral. Our test isolates the covariance structure of neutral competition, thus facilitating further exploration of the nature of asymmetry in the covariance structure of competitive systems. Much like neutrality tests from population genetics that use relative abundance distributions have enabled researchers to scan entire genomes for genes under selection, we anticipate our time-series test will be useful for quick significance tests of neutrality across a range of ecological, economic, and sociological systems for which time-series data are available. Future work can use our test to categorize and compare the dynamic fingerprints of particular competitive asymmetries (frequency dependence, volatility smiles, etc) to improve forecasting and management of complex adaptive systems. PMID:27689714

Hepatitis C seropositivity is not a risk factor for sensory neuropathy among patients with HIV

PubMed Central

Cherry, C.L.; Affandi, J.S.; Brew, B.J.; Creighton, J.; Djauzi, S.; Hooker, D.J.; Imran, D.; Kamarulzaman, A.; Kamerman, P.; McArthur, J.C.; Moore, R.D.; Price, P.; Smyth, K.; Tan, I.L.; Vanar, S.; Wadley, A.; Wesselingh, S.L.; Yunihastuti, E.

2010-01-01

Background: Sensory neuropathy (SN) is common in patients with HIV. Hepatitis C (HCV) coinfection is often cited as an HIV-SN risk factor, but data to support this are lacking. This collaboration aimed to examine the association between HCV serostatus and SN risk among ambulatory HIV-positive patients. Methods: Patients with HIV were assessed in cross-sectional studies in Baltimore, Jakarta, Johannesburg, Kuala Lumpur, Melbourne, and Sydney for SN (defined by both supportive symptoms and signs). HCV seropositivity was assessed as an SN risk using a χ2 test, followed by logistic regression modeling to correct for treatment exposures and demographics. Results: A total of 837 patients of African, Asian, and Caucasian descent were studied. HCV seroprevalence varied by site (Baltimore n = 104, 61% HCV+; Jakarta 96, 51%; Johannesburg 300, 1%; Kuala Lumpur 97, 10%; Melbourne 206, 16%; Sydney 34, 18%). HCV seropositivity was not associated with increased SN risk at any site, but was associated with reduced SN risk in Melbourne (p = 0.003). On multivariate analyses, the independent associations with SN were increasing age, height, and stavudine exposure. HCV seropositivity was not independently associated with an increased SN risk at any site, but associated independently with reduced SN risk in Baltimore (p = 0.04) and Melbourne (p = 0.06). Conclusions: Hepatitis C (HCV) seropositivity was not associated with increased sensory neuropathy risk among HIV-positive patients at any site. While we were unable to assess HCV RNA or liver damage, the data suggest that HCV coinfection is not a major contributor to HIV-SN. GLOSSARY HCV = hepatitis C; SN = sensory neuropathy. PMID:20458071

Type Ia supernovae: Pulsating delayed detonation models, IR light curves, and the formation of molecules

NASA Technical Reports Server (NTRS)

Hoflich, Peter; Khokhlov, A.; Wheeler, C.

1995-01-01

We computed optical and infrared light curves of the pulsating class of delayed detonation models for Type Ia supernovae (SNe Ia). It is demonstrated that observations of the IR light curves can be used to identify subluminous SNe Ia by testing whether secondary maxima occur in the IR. Our pulsating delayed detonation models are in agreement with current observations both for subluminous and normal bright SN Ia, namely SN1991bg, SN1992bo, and SN1992bc. Observations of molecular bands provide a test to distinguish whether strongly subluminous supernovae are a consequence of the pulsating mechanism occurring in a high-mass white dwarf (WD) or, alternatively, are formed by the helium detonation in a low-mass WD as was suggested by Woosley. In the latter case, no carbon is left after the explosion of low-mass WDs whereas a log of C/O-rich material is present in pulsating delayed detonation models.

Correlation between the oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys

NASA Astrophysics Data System (ADS)

Park, Sang-Yoon; Lee, Myung-Ho; Jeong, Yong-Hwan; Jung, Youn-Ho

2004-12-01

The correlation between the oxide impedance and corrosion behavior of two series of Zr-Nb-Sn-Fe-Cu alloys was evaluated. Corrosion tests were performed in a 70 ppm LiOH aqueous solution at 360°C for 300 days. The results of the corrosion tests revealed that the corrosion behavior of the alloys depended on the Nb and Sn content. The impedance characteristics for the pre- and post-transition oxide layers formed on the surface of the alloys were investigated in sulfuric acid at room temperature. From the results, a pertinent equivalent circuit model was preferably established, explaining the properties of double oxide layers. The impedance of the oxide layers correlated with the corrosion behavior; better corrosion resistance always showed higher electric resistance for the inner layers. It is thus concluded that a pertinent equivalent circuit model would be useful for evaluating the long-term corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys.

The Influence of Processing on Strengthening Mechanisms in Pb-Free Solder Joints

NASA Astrophysics Data System (ADS)

Mutuku, Francis; Arfaei, Babak; Cotts, Eric J.

2017-04-01

The number, and the spacing, of Ag3Sn precipitates in Sn-Ag-Cu/Cu solder joints were related to separate processing parameters. The mechanical properties of an individual solder joint were directly related to the resulting distribution of different dispersoids in the joint. As the number of Ag3Sn precipitates increased, so did solder joint strength and shear fatigue lifetime. The room-temperature shear fatigue lifetime was inversely correlated with the separation between Ag3Sn precipitates. Bi and Sb solid solution strengthening was found to result in significantly larger values of shear strength and shear fatigue lifetime for one Pb-free solder. Room-temperature shear fatigue lifetime tests were identified as a relatively straightforward, yet sensitive means to gain insight into the reliability of Sn-Ag-Cu (SAC) solder joints.

Wet Chemical Synthesis of SnS/Graphene Nanocomposites for High Performance Supercapacitor Electrodes

NASA Astrophysics Data System (ADS)

Ravuri, Syamsai; Pandey, Chandan Abhishek; Ramchandran, R.; Jeon, Soon Kwan; Grace, Andrews Nirmala

A series of SnS/Graphene (SnS/G) nanocomposites at various concentrations of graphene were synthesized by a wet chemical route and the prepared composites were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HRTEM) for its structural and morphological investigation. Results show that the prepared SnS nanoparticles in the composite are ˜30nm sized and uniformly dispersed on graphene sheets. To test the supercapacitance behavior, electrochemical measurements were carried out in 6M KOH electrolyte. A maximum specific capacitance of 984F/g was observed for SnS/G-c at 5mVs-1 scan rate. Galvanostatic charge/discharge curves showed an excellent cyclic stability with higher charge/discharge duration, and hence could be used for high performance supercapacitor applications.

LED Die-Bonded on the Ag/Cu Substrate by a Sn-BiZn-Sn Bonding System

NASA Astrophysics Data System (ADS)

Tang, Y. K.; Hsu, Y. C.; Lin, E. J.; Hu, Y. J.; Liu, C. Y.

2016-12-01

In this study, light emitting diode (LED) chips were die-bonded on a Ag/Cu substrate by a Sn-BixZn-Sn bonding system. A high die-bonding strength is successfully achieved by using a Sn-BixZn-Sn ternary system. At the bonding interface, there is observed a Bi-segregation phenomenon. This Bi-segregation phenomenon solves the problems of the brittle layer-type Bi at the joint interface. Our shear test results show that the bonding interface with Bi-segregation enhances the shear strength of the LED die-bonding joints. The Bi-0.3Zn and Bi-0.5Zn die-bonding cases have the best shear strength among all die-bonding systems. In addition, we investigate the atomic depth profile of the deposited Bi-xZn layer by evaporating Bi-xZn E-gun alloy sources. The initial Zn content of the deposited Bi-Zn alloy layers are much higher than the average Zn content in the deposited Bi-Zn layers.

A Fast Humidity Sensor Based on Li+-Doped SnO2 One-Dimensional Porous Nanofibers

PubMed Central

Yin, Min; Yang, Fang; Wang, Zhaojie; Zhu, Miao; Liu, Ming; Xu, Xiuru; Li, Zhenyu

2017-01-01

One-dimensional SnO2- and Li+-doped SnO2 porous nanofibers were easily fabricated via electrospinning and a subsequent calcination procedure for ultrafast humidity sensing. Different Li dopant concentrations were introduced to investigate the dopant’s role in sensing performance. The response properties were studied under different relative humidity levels by both statistic and dynamic tests. The best response was obtained with respect to the optimal doping of Li+ into SnO2 porous nanofibers with a maximum 15 times higher response than that of pristine SnO2 porous nanofibers, at a relative humidity level of 85%. Most importantly, the ultrafast response and recovery time within 1 s was also obtained with the 1.0 wt % doping of Li+ into SnO2 porous nanofibers at 5 V and at room temperature, benefiting from the co-contributions of Li-doping and the one-dimensional porous structure. This work provides an effective method of developing ultrafast sensors for practical applications—especially fast breathing sensors. PMID:28772895

A solar-thermal energy harvesting scheme: enhanced heat capacity of molten HITEC salt mixed with Sn/SiO(x) core-shell nanoparticles.

PubMed

Lai, Chih-Chung; Chang, Wen-Chih; Hu, Wen-Liang; Wang, Zhiming M; Lu, Ming-Chang; Chueh, Yu-Lun

2014-05-07

We demonstrated enhanced solar-thermal storage by releasing the latent heat of Sn/SiO(x) core-shell nanoparticles (NPs) embedded in a eutectic salt. The microstructures and chemical compositions of Sn/SiO(x) core-shell NPs were characterized. In situ heating XRD provides dynamic crystalline information about the Sn/SiO(x) core-shell NPs during cyclic heating processes. The latent heat of ∼29 J g(-1) for Sn/SiO(x) core-shell NPs was measured, and 30% enhanced heat capacity was achieved from 1.57 to 2.03 J g(-1) K(-1) for the HITEC solar salt without and with, respectively, a mixture of 5% Sn/SiO(x) core-shell NPs. In addition, an endurance cycle test was performed to prove a stable operation in practical applications. The approach provides a method to enhance energy storage in solar-thermal power plants.

The Effect of Zeolite Composition and Grain Size on Gas Sensing Properties of SnO₂/Zeolite Sensor.

PubMed

Sun, Yanhui; Wang, Jing; Li, Xiaogan; Du, Haiying; Huang, Qingpan; Wang, Xiaofeng

2018-01-29

In order to improve the sensing properties of tin dioxide gas sensor, four kinds of different SiO₂/Al₂O₃ ratio, different particle size of MFI type zeolites (ZSM-5) were coated on the SnO₂ to prepared zeolite modified gas sensors, and the gas sensing properties were tested. The measurement results showed that the response values of ZSM-5 zeolite (SiO₂/Al₂O₃ = 70, grain size 300 nm) coated SnO₂ gas sensors to formaldehyde vapor were increased, and the response to acetone decreased compared with that of SnO₂ gas sensor, indicating an improved selectivity property. The other three ZSM-5 zeolites with SiO₂/Al₂O₃ 70, 150 and 470, respectively, and grain sizes all around 1 μm coated SnO₂ sensors did not show much difference with SnO₂ sensor for the response properties to both formaldehyde and acetone. The sensing mechanism of ZSM-5 modified sensors was briefly analyzed.

Synthesis, characterization and biocidal activity of new organotin complexes of 2-(3-oxocyclohex-1-enyl)benzoic acid.

PubMed

Vieira, Flaviana T; de Lima, Geraldo M; Maia, José R da S; Speziali, Nivaldo L; Ardisson, José D; Rodrigues, Leonardo; Correa, Ary; Romero, Oscar B

2010-03-01

The reaction of 1,3-cyclohexadione with 2-aminobenzoic acid has produced the 2-(3-oxocyclohex-1-enyl)benzoic acid (HOBz). Subsequent reactions of the ligand with organotin chlorides led to [Me(2)Sn(OBz)O](2) (1), [Bu(2)Sn(OBz)O](2) (2), [Ph(2)Sn(OBz)O](2) (3), [Me(3)Sn(OBz)] (4), [Bu(3)Sn(OBz)] (5) and [Ph(3)Sn(OBz)] (6). All complexes have been fully characterized. In addition the structure of complexes (2) and (4) have been authenticated by X-ray crystallography. The biological activity of all derivatives has been screened against Cryptococcus neoformans and Candida albicans. In addition we have performed toxicological testes employing human kidney cell. The complexes (3), (5) and (6) displayed the best values of inhibition of the fungus growing, superior to ketoconazole. Compound (5) presented promising results in view of the antifungal and cytotoxicity assays. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

Do supernovae of type 1 paly a role in cosmic-ray production?

NASA Technical Reports Server (NTRS)

Shapiro, M. M.

1985-01-01

A model of cosmic-ray origin is suggested which aims to account for some salient features of the composition. Relative to solar abundances, the Galactic cosmic rays (GCR) are deficient in hydrogen and helim (H and He) by an order of magnitude when the two compositions are normalized at iron. Our conjectural model implicates supernovae of Type I (SN-I) as sources of some of the GCR. SN-I occur approximately as often as SN-II, through their genesis is thought to be different. Recent studies of nucleosynthesis in SN-I based on accreting white dwarfs, find that the elements from Si to Fe are produced copiously. On the other hand, SN-I are virtually devoid of hydrogen, and upper limits deduced for He are low. If SN-I contribute significantly to the pool of GCR by injecting energetic particles into the interstellar medium (ISM), then this could explain why the resulting GCR is relatively deficient in H and He. A test of the model is proposed, and difficulties are discussed.

A TYPE Ia SUPERNOVA AT REDSHIFT 1.55 IN HUBBLE SPACE TELESCOPE INFRARED OBSERVATIONS FROM CANDELS

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

Rodney, Steven A.; Riess, Adam G.; Jones, David O.

2012-02-10

We report the discovery of a Type Ia supernova (SN Ia) at redshift z = 1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search components from those two HST multi-cycle treasury programs. This is the highest redshift SN Ia with direct spectroscopic evidence for classification. It is also the first SN Ia at z > 1 found and followed in the infrared, providing amore » full light curve in rest-frame optical bands. The classification and redshift are securely defined from a combination of multi-band and multi-epoch photometry of the SN, ground-based spectroscopy of the host galaxy, and WFC3-IR grism spectroscopy of both the SN and host. This object is the first of a projected sample at z > 1.5 that will be discovered by the CANDELS and CLASH programs. The full CANDELS+CLASH SN Ia sample will enable unique tests for evolutionary effects that could arise due to differences in SN Ia progenitor systems as a function of redshift. This high-z sample will also allow measurement of the SN Ia rate out to z Almost-Equal-To 2, providing a complementary constraint on SN Ia progenitor models.« less

Expression, purification and characterization of the recombinant cysteine-rich antimicrobial peptide snakin-1 in Pichia pastoris.

PubMed

Kuddus, Md Ruhul; Rumi, Farhana; Tsutsumi, Motosuke; Takahashi, Rika; Yamano, Megumi; Kamiya, Masakatsu; Kikukawa, Takashi; Demura, Makoto; Aizawa, Tomoyasu

2016-06-01

Snakin-1 (SN-1) is a small cysteine-rich plant antimicrobial peptide with broad spectrum antimicrobial activity which was isolated from potato (Solanum tuberosum). Here, we carried out the expression of a recombinant SN-1 in the methylotrophic yeast Pichia pastoris, along with its purification and characterization. A DNA fragment encoding the mature SN-1 was cloned into pPIC9 vector and introduced into P. pastoris. A large amount of pure recombinant SN-1 (approximately 40 mg/1L culture) was obtained from a fed-batch fermentation culture after purification with a cation exchange column followed by RP-HPLC. The identity of the recombinant SN-1 was verified by MALDI-TOF MS, CD and (1)H NMR experiments. All these data strongly indicated that the recombinant SN-1 peptide had a folding with six disulfide bonds that was identical to the native SN-1. Our findings showed that SN-1 exhibited strong antimicrobial activity against test microorganisms and produced very weak hemolysis of mammalian erythrocytes. The mechanism of its antimicrobial action against Escherichia coli was investigated by both outer membrane permeability assay and cytoplasmic membrane depolarization assay. These assays demonstrated that SN-1 is a membrane-active antimicrobial peptide which can disrupt both outer and cytoplasmic membrane integrity. This is the first report on the recombinant expression and purification of a fully active SN-1 in P. pastoris. Copyright © 2016 Elsevier Inc. All rights reserved.

Selective Improvement of NO2 Gas Sensing Behavior in SnO2 Nanowires by Ion-Beam Irradiation.

PubMed

Kwon, Yong Jung; Kang, Sung Yong; Wu, Ping; Peng, Yuan; Kim, Sang Sub; Kim, Hyoun Woo

2016-06-01

We irradiated SnO2 nanowires with He ions (45 MeV) with different ion fluences. Structure and morphology of the SnO2 nanowires did not undergo noticeable changes upon ion-beam irradiation. Chemical equilibrium in SnO2/gas systems was calculated from thermodynamic principles, which were used to study the sensing selectivity of the tested gases, demonstrating the selective sensitivity of the SnO2 surface to NO2 gas. Being different from other gases, including H2, ethanol, acetone, SO2, and NH3, the sensor response to NO2 gas significantly increases as the ion fluence increases, showing a maximum under an ion fluence of 1 × 10(16) ions/cm(2). Photoluminescence analysis shows that the relative intensity of the peak at 2.1 eV to the peak at 2.5 eV increases upon ion-beam irradiation, suggesting that structural defects and/or tin interstitials have been generated. X-ray photoelectron spectroscopy indicated that the ionic ratio of Sn(2+/)Sn(4+) increases by the ion-beam irradiation, supporting the formation of surface Sn interstitials. Using thermodynamic calculations, we explained the observed selective sensing behavior. A molecular level model was also established for the adsorption of NO2 on ion-irradiated SnO2 (110) surfaces. We propose that the adsorption of NO2-related species is considerably enhanced by the generation of surface defects that are comprised of Sn interstitials.

Tailoring Morphology and Size of Microstructure and Tensile Properties of Sn-5.5 wt.%Sb-1 wt.%(Cu,Ag) Solder Alloys

NASA Astrophysics Data System (ADS)

Dias, Marcelino; Costa, Thiago A.; Soares, Thiago; Silva, Bismarck L.; Cheung, Noé; Spinelli, José E.; Garcia, Amauri

2018-02-01

Transient directional solidification experiments, and further optical and scanning electron microscopy analyses and tensile tests, allowed the dependence of tensile properties on the micromorphology and length scale of the dendritic/cellular matrix of ternary Sn-5.5Sb-1Ag and Sn-5.5Sb-1Cu alloys to be determined. Extensive ranges of cooling rates were obtained, which permitted specific values of cooling rate for each sample examined along the length of the casting to be attributed. Very broad microstructural length scales were revealed as well as the presence of either cells or dendrites for the Ag-containing alloy. Hereafter, microstructural spacing values such as the cellular spacing, λ c, and the primary dendritic spacing, λ 1, may be correlated with thermal solidification parameters, that is, the cooling rate and the growth rate. While, for the Cu-containing Sn-Sb alloy, the β-Sn matrix is characterized only by the presence of dendritic arrangements, the Ag-containing Sn-Sb alloy is shown to have high-velocity β-Sn cells associated with high cooling rate regions, i.e., positions closer to the bottom of the alloy casting, with the remaining positions being characterized by a complex growth of β-Sn dendrites. Minor additions of Cu and Ag increase both the yield and ultimate tensile strengths when compared with the corresponding values of the binary Sn-5.5Sb alloy, with a small reduction in ductility. This has been attributed to the homogeneous distribution of the Ag3Sn and Cu6Sn5 intermetallic particles related to smaller λ 1 characterizing the dendritic zones of the ternary Sn-Sb-(Cu,Ag) alloys. In addition, the Ag-modified Sn-Sb alloy exhibited an initial wetting angle consistent with that characterizing the binary Sn-5.5Sb alloy.

Development, Validation, and Field-Testing of an Instrument for Clinical Assessment of HIV-Associated Neuropathy and Neuropathic Pain in Resource-Restricted and Large Population Study Settings

PubMed Central

Kamerman, Peter R.; Veliotes, Demetri G. A.; Phillips, Tudor J.; Asboe, David; Boffito, Marta; Rice, Andrew S. C.

2016-01-01

HIV-associated sensory peripheral neuropathy (HIV-SN) afflicts approximately 50% of patients on antiretroviral therapy, and is associated with significant neuropathic pain. Simple accurate diagnostic instruments are required for clinical research and daily practice in both high- and low-resource setting. A 4-item clinical tool (CHANT: Clinical HIV-associated Neuropathy Tool) assessing symptoms (pain and numbness) and signs (ankle reflexes and vibration sense) was developed by selecting and combining the most accurate measurands from a deep phenotyping study of HIV positive people (Pain In Neuropathy Study–HIV-PINS). CHANT was alpha-tested in silico against the HIV-PINS dataset and then clinically validated and field-tested in HIV-positive cohorts in London, UK and Johannesburg, South Africa. The Utah Early Neuropathy Score (UENS) was used as the reference standard in both settings. In a second step, neuropathic pain in the presence of HIV-SN was assessed using the Douleur Neuropathique en 4 Questions (DN4)-interview and a body map. CHANT achieved high accuracy on alpha-testing with sensitivity and specificity of 82% and 90%, respectively. In 30 patients in London, CHANT diagnosed 43.3% (13/30) HIV-SN (66.7% with neuropathic pain); sensitivity = 100%, specificity = 85%, and likelihood ratio = 6.7 versus UENS, internal consistency = 0.88 (Cronbach alpha), average item-total correlation = 0.73 (Spearman’s Rho), and inter-tester concordance > 0.93 (Spearman’s Rho). In 50 patients in Johannesburg, CHANT diagnosed 66% (33/50) HIV-SN (78.8% neuropathic pain); sensitivity = 74.4%, specificity = 85.7%, and likelihood ratio = 5.29 versus UENS. A positive CHANT score markedly increased of pre- to post-test clinical certainty of HIV-SN from 43% to 83% in London, and from 66% to 92% in Johannesburg. In conclusion, a combination of four easily and quickly assessed clinical items can be used to accurately diagnose HIV-SN. DN4-interview used in the context of bilateral feet pain can be used to identify those with neuropathic pain. PMID:27764177

Electromigration Mechanism of Failure in Flip-Chip Solder Joints Based on Discrete Void Formation.

PubMed

Chang, Yuan-Wei; Cheng, Yin; Helfen, Lukas; Xu, Feng; Tian, Tian; Scheel, Mario; Di Michiel, Marco; Chen, Chih; Tu, King-Ning; Baumbach, Tilo

2017-12-20

In this investigation, SnAgCu and SN100C solders were electromigration (EM) tested, and the 3D laminography imaging technique was employed for in-situ observation of the microstructure evolution during testing. We found that discrete voids nucleate, grow and coalesce along the intermetallic compound/solder interface during EM testing. A systematic analysis yields quantitative information on the number, volume, and growth rate of voids, and the EM parameter of DZ*. We observe that fast intrinsic diffusion in SnAgCu solder causes void growth and coalescence, while in the SN100C solder this coalescence was not significant. To deduce the current density distribution, finite-element models were constructed on the basis of the laminography images. The discrete voids do not change the global current density distribution, but they induce the local current crowding around the voids: this local current crowding enhances the lateral void growth and coalescence. The correlation between the current density and the probability of void formation indicates that a threshold current density exists for the activation of void formation. There is a significant increase in the probability of void formation when the current density exceeds half of the maximum value.

Round Robin Test of Residual Resistance Ratio of Nb$$_3$$Sn Composite Superconductors

DOE PAGES

Matsushita, Teruo; Otabe, Edmund Soji; Kim, Dong Ho; ...

2017-12-07

A round robin test of residual resistance ratio (RRR) was performed for Nb 3Sn composite superconductors prepared by internal tin method by six institutes with the international standard test method described in IEC 61788-4. It was found that uncertainty mainly resulted from determination of the cryogenic resistance from the intersection of two straight lines drawn to fit the voltage vs. temperature curve around the resistive transition. As a result, the measurement clarified that RRR can be measured with expanded uncertainty not larger than 5% with the coverage factor 2 by using this test method.

Round Robin Test of Residual Resistance Ratio of Nb$$_3$$Sn Composite Superconductors

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

Matsushita, Teruo; Otabe, Edmund Soji; Kim, Dong Ho

A round robin test of residual resistance ratio (RRR) was performed for Nb 3Sn composite superconductors prepared by internal tin method by six institutes with the international standard test method described in IEC 61788-4. It was found that uncertainty mainly resulted from determination of the cryogenic resistance from the intersection of two straight lines drawn to fit the voltage vs. temperature curve around the resistive transition. As a result, the measurement clarified that RRR can be measured with expanded uncertainty not larger than 5% with the coverage factor 2 by using this test method.

Synthesis and Enhanced Ethanol Gas Sensing Properties of the g-C3N4 Nanosheets-Decorated Tin Oxide Flower-Like Nanorods Composite

PubMed Central

Qin, Cong; Zhang, Bo; Sun, Guang; Zhang, Zhanying

2017-01-01

Flower-like SnO2/g-C3N4 nanocomposites were synthesized via a facile hydrothermal method by using SnCl4·5H2O and urea as the precursor. The structure and morphology of the as-synthesized samples were characterized by using the X-ray powder diffraction (XRD), electron microscopy (FESEM and TEM), and Fourier transform infrared spectrometer (FT-IR) techniques. SnO2 displays the unique 3D flower-like microstructure assembled with many uniform nanorods with the lengths and diameters of about 400–600 nm and 50–100 nm, respectively. For the SnO2/g-C3N4 composites, SnO2 flower-like nanorods were coupled by a lamellar structure 2D g-C3N4. Gas sensing performance test results indicated that the response of the sensor based on 7 wt. % 2D g-C3N4-decorated SnO2 composite to 500 ppm ethanol vapor was 150 at 340 °C, which was 3.5 times higher than that of the pure flower-like SnO2 nanorods-based sensor. The gas sensing mechanism of the g-C3N4nanosheets-decorated SnO2 flower-like nanorods was discussed in relation to the heterojunction structure between g-C3N4 and SnO2. PMID:28937649

SIG Galileo final converter technical summary report

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

Hinderman, J.D.

1979-05-01

The report is primarily concerned with the work performed for DOE on converter development and fabrication for the NASA Galileo Jupiter mission as a DOE prime contractor with interface primarily with Teledyne Energy Systems. The activities reported on were directed toward design, analysis and testing of modules and converters SN-1 thru SN-7 and attendant Quality Control and Reliability effort. Although assembly and testing of SN-1 was not accomplished due to the stop work order, the design was virtually completed and a significant amount of subcontracting and manufacturing of both module and converter components was underway. These subcontracting and manufacturing activitiesmore » were selectively closed down depending upon degree of completion and material or hardware potential usage in the Technology Program.« less

Economic manufacturing of bulk metallic glass compositions by microalloying

DOEpatents

Liu, Chain T.

2003-05-13

A method of making a bulk metallic glass composition includes the steps of:a. providing a starting material suitable for making a bulk metallic glass composition, for example, BAM-11; b. adding at least one impurity-mitigating dopant, for example, Pb, Si, B, Sn, P, to the starting material to form a doped starting material; and c. converting the doped starting material to a bulk metallic glass composition so that the impurity-mitigating dopant reacts with impurities in the starting material to neutralize deleterious effects of the impurities on the formation of the bulk metallic glass composition.

Field emission from in situ-grown vertically aligned SnO2 nanowire arrays

PubMed Central

2012-01-01

Vertically aligned SnO2 nanowire arrays have been in situ fabricated on a silicon substrate via thermal evaporation method in the presence of a Pt catalyst. The field emission properties of the SnO2 nanowire arrays have been investigated. Low turn-on fields of 1.6 to 2.8 V/μm were obtained at anode-cathode separations of 100 to 200 μm. The current density fluctuation was lower than 5% during a 120-min stability test measured at a fixed applied electric field of 5 V/μm. The favorable field-emission performance indicates that the fabricated SnO2 nanowire arrays are promising candidates as field emitters. PMID:22330800

Ru-Sn/AC for the Aqueous-Phase Reduction of Succinic Acid to 1,4-Butanediol under Continuous Process Conditions

DOE PAGES

Vardon, Derek R.; Settle, Amy E.; Vorotnikov, Vassili; ...

2017-08-18

Succinic acid is a biomass-derived platform chemical that can be catalytically converted in the aqueous phase to 1,4-butanediol (BDO), a prevalent building block used in the polymer and chemical industries. Despite significant interest, limited work has been reported regarding sustained catalyst performance and stability under continuous aqueous-phase process conditions. As such, this work examines Ru-Sn on activated carbon (AC) for the aqueous-phase conversion of succinic acid to BDO under batch and flow reactor conditions. Initially, powder Ru-Sn catalysts were screened to determine the most effective bimetallic ratio and provide a comparison to other monometallic (Pd, Pt, Ru) and bimetallic (Pt-Sn,more » Pd-Re) catalysts. Batch reactor tests determined that a ~1:1 metal weight ratio of Ru to Sn was effective for producing BDO in high yields, with complete conversion resulting in 82% molar yield. Characterization of the fresh Ru-Sn catalyst suggests that the sequential loading method results in Ru sites that are colocated and surface-enriched with Sn. Postbatch reaction characterization confirmed stable Ru-Sn material properties; however, upon a transition to continuous conditions, significant Ru-Sn/AC deactivation occurred due to stainless steel leaching of Ni that resulted in Ru-Sn metal crystallite restructuring to form discrete Ni-Sn sites. Computational modeling confirmed favorable energetics for Ru-Sn segregation and Ni-Sn formation at submonolayer Sn incorporation. To address stainless steel leaching, reactor walls were treated with an inert silica coating by chemical vapor deposition. With leaching reduced, stable Ru-Sn/AC performance was observed that resulted in a molar yield of 71% BDO and 15% tetrahydrofuran for 96 h of time on stream. Postreaction catalyst characterization confirmed low levels of Ni and Cr deposition, although early-stage islanding of Ni-Sn will likely be problematic for industrially relevant time scales (i.e., thousands of hours). Overall, these results (i) demonstrate the performance of Ru-Sn/AC for aqueous phase succinic acid reduction, (ii) provide insight into the Ru-Sn bimetallic structure and deactivation in the presence of leached Ni, and (iii) underscore the importance of compatible reactor metallurgy and durable catalysts.« less

Cloning of the cDNA for U1 small nuclear ribonucleoprotein particle 70K protein from Arabidopsis thaliana

NASA Technical Reports Server (NTRS)

Reddy, A. S.; Czernik, A. J.; An, G.; Poovaiah, B. W.

1992-01-01

We cloned and sequenced a plant cDNA that encodes U1 small nuclear ribonucleoprotein (snRNP) 70K protein. The plant U1 snRNP 70K protein cDNA is not full length and lacks the coding region for 68 amino acids in the amino-terminal region as compared to human U1 snRNP 70K protein. Comparison of the deduced amino acid sequence of the plant U1 snRNP 70K protein with the amino acid sequence of animal and yeast U1 snRNP 70K protein showed a high degree of homology. The plant U1 snRNP 70K protein is more closely related to the human counter part than to the yeast 70K protein. The carboxy-terminal half is less well conserved but, like the vertebrate 70K proteins, is rich in charged amino acids. Northern analysis with the RNA isolated from different parts of the plant indicates that the snRNP 70K gene is expressed in all of the parts tested. Southern blotting of genomic DNA using the cDNA indicates that the U1 snRNP 70K protein is coded by a single gene.

Effects of Sn addition on the microstructure and tensile properties of AX55 alloys

NASA Astrophysics Data System (ADS)

Qiu, K. Q.; Huang, P.

2018-04-01

The microstructures and tensile properties at both room and elevated temperatures for both the as-cast and as-aged Mg-5Al-5Ca (AX55) alloy with 0–2 wt% Sn addition were studied. The results indicate that the α-Mg dendrite is gradually refined and the interdendritic Al2Ca and Mg2Ca intermetallics become more connected with Sn addition. The as-cast AX55-1Sn alloy shows optimal ultimate tensile strength (UTS) at testing temperature from 25 to 225 °C. After T61 and T62 heat treatment, the eutectic-lamellar microstructure of the as-cast alloys tends to be spheroidized and distributed uniformly along the grain boundaries. While the alloys with higher Sn content show higher density of granulated and needle-shaped Al2Ca phases precipitated into α-Mg matrix, which results in the increase of UTS, yield strength (YS), elongation and microhardness with Sn addition. The morphology of CaMgSn phase can be improved by T62 treatment, which makes as-aged AX55-2.0Sn alloy exhibit a smaller decrease rate of the UTS at temperature up to 225 °C. The heat resistance of different heat-resistant magnesium alloys were compared and discussed by using the decrease rate of the UTS.

Nanocomposite SAC Solders: The Effect of Adding Ni and Ni-Sn Nanoparticles on Morphology and Mechanical Properties of Sn-3.0Ag-0.5Cu Solders

NASA Astrophysics Data System (ADS)

Yakymovych, A.; Švec, P.; Orovcik, L.; Bajana, O.; Ipser, H.

2018-01-01

This study investigates the effect of minor additions of Ni, Ni3Sn or Ni3Sn2 nanoparticles on the microstructure and mechanical properties of Cu/solder/Cu joints. The nanocomposite Sn-3.0Ag-0.5Cu (SAC305) solders with 0.5, 1.0 and 2.0 wt.% metallic nanoparticles were prepared through a paste mixing method. The employed Ni and Ni-Sn nanoparticles were produced via a chemical reduction method. The microstructure of as-solidified Cu/solder/Cu joints was studied by x-ray diffraction and scanning electron microscopy. The results showed that additions of Ni and Ni-Sn nanoparticles to the SAC305 solder paste lead initially to a decrease in the average thickness of the intermetallic compound layer in the interface between solder and substrate, while further additions up to 2.0 wt.% did not induce any significant changes. In addition, shear strength and microhardness tests were performed to investigate the relationship between microstructure and mechanical properties of the investigated solder joints. The results indicated an increase in both of these properties which was most significant for the solder joints using SAC305 with 0.5 wt.% Ni or Ni-Sn nanoparticles.

Magnetic Measurements of the First Nb 3Sn Model Quadrupole (MQXFS) for the High-Luminosity LHC

DOE PAGES

DiMarco, J.; Ambrosio, G.; Chlachidze, G.; ...

2016-12-12

The US LHC Accelerator Research Program (LARP) and CERN are developing high-gradient Nb 3Sn magnets for the High Luminosity LHC interaction regions. Magnetic measurements of the first 1.5 m long, 150 mm aperture model quadrupole, MQXFS1, were performed during magnet assembly at LBNL, as well as during cryogenic testing at Fermilab’s Vertical Magnet Test Facility. This paper reports on the results of these magnetic characterization measurements, as well as on the performance of new probes developed for the tests.

Pitfalls in efficacy testing--how important is the validation of neutralization of chlorhexidine digluconate?

PubMed

Reichel, Mirja; Heisig, Peter; Kampf, Günter

2008-12-02

Effective neutralization of active agents is essential to obtain valid efficacy results, especially when non-volatile active agents like chlorhexidine digluconate (CHG) are tested. The aim of this study was to determine an effective and non-toxic neutralizing mixture for a propan-1-ol solution containing 2% CHG. Experiments were carried out according to ASTM E 1054-02. The neutralization capacity was tested separately with five challenge microorganisms in suspension, and with a rayon swab carrier. Either 0.5 mL of the antiseptic solution (suspension test) or a saturated swab with the antiseptic solution (carrier test) was added to tryptic soy broth containing neutralizing agents. After the samples were mixed, aliquots were spread immediately and after 3 h of storage at 2 - 8 degrees C onto tryptic soy agar containing a neutralizing mixture. The neutralizer was, however, not consistently effective in the suspension test. Immediate spread yielded a valid neutralization with Staphylococcus aureus, Staphylococcus epidermidis and Corynebacterium jeikeium but not with Micrococcus luteus (p < 0.001) and Candida albicans (p < 0.001). A 3-h storage period of the neutralized active agents in suspension resulted in significant carry-over activity of CHG in addition against Staphylococcus epidermidis (p < 0.001) and Corynebacterium jeikeium (p = 0.044). In the carrier test, the neutralizing mixture was found to be effective and non toxic to all challenge microorganisms when spread immediately. However, after 3 h storage of the neutralized active agents significant carry-over activity of CHG against Micrococcus luteus (p = 0.004; Tukey HSD) was observed. Without effective neutralization in the sampling fluid, non-volatile active ingredients will continue to reduce the number of surviving microorganisms after antiseptic treatment even if the sampling fluid is kept cold straight after testing. This can result in false-positive antiseptic efficacy data. Attention should be paid during the neutralization validation process to the amount of antiseptic solution, the storage time and to the choice of appropriate and sensitive microorganisms.

Corrosion management of PbCaSn alloys in lead-acid batteries: Effect of composition, metallographic state and voltage conditions

NASA Astrophysics Data System (ADS)

Rocca, E.; Bourguignon, G.; Steinmetz, J.

Since several years, lead calcium-based alloys have supplanted lead antimony alloys as structural materials for positive grids of lead-acid batteries in many applications, especially for VRLA batteries. Nevertheless, the positive grid corrosion probably remains one of the causes of rapid and premature failure of lead-acid batteries. The objective of the present study is to present a comprehensive study of the PbCaSn alloy corrosion in function of their composition, metallographic state and voltage conditions (discharge, overcharge, floating and cycling conditions). For that, four alloys PbCaSn x wt.% (x = 0, 0.6, 1.2, 2) were synthesized in two extreme metallurgical conditions and tested by four electrochemical lab-tests. Weight loss measurements and analyses by SEM, EPMA and XRD allowed to monitor the oxidation tests and to characterize the corrosion layers after the oxidation tests. The results show that the tin level in PbCaSn alloys should be adapted on the calcium concentration and the rate of overageing process, to maintain the beneficial effect of tin in service during the battery lifetime. According to our results, a Sn/Ca ratio of 2.5 gives good corrosion resistance in all potential conditions. Nevertheless, when tin level is too high, the corrosion layers can peel off from the metal, which involves a lack of cohesion between the collector and the paste, in cycling conditions. The anodic potential undergone by the metal is a second main factor determining the corrosion, especially the floating conditions and the frequency of deep discharge and overcharge. Thus the adjustment of the charge controller parameters of a battery system is a necessity to increase the lifetime of the grids and maintain a good rechargeability.

The Effect of Sn Orientation on Intermetallic Compound Growth in Idealized Sn-Cu-Ag Interconnects

NASA Astrophysics Data System (ADS)

Kinney, Chris; Linares, Xioranny; Lee, Kyu-Oh; Morris, J. W.

2013-04-01

The work reported here explores the influence of crystal orientation on the growth of the interfacial intermetallic layer during electromigration in Cu||Sn||Cu solder joints. The samples were thin, planar Sn-Ag-Cu (SAC) solder layers between Cu bars subject to a uniaxial current. Electron backscatter diffraction (EBSD) was used to characterize the microstructure before and after testing. The most useful representation of the EBSD data identifies the Sn grain orientation by the angle between the Sn c-axis and the current direction. The tested samples included single-crystal joints with c-axis nearly parallel to the current ("green" samples) and with c-axis perpendicular to the current ("red" samples). At current density of 104 A/cm2 (steady-state temperature of ~150°C), an intermetallic layer grew at an observable rate in the "green" samples, but not in the "red" ones. A current density of 1.15 × 104 A/cm2 (temperature ~160°C) led to measurable intermetallic growth in both samples. The growth fronts were nearly planar and the growth rates constant (after an initial incubation period); the growth rates in the "green" samples were about 10× those in the "red" samples. The Cu concentrations were constant within the joints, showing that the intermetallic growth is dominated by the electromigration flux. The measured growth rates and literature values for the diffusion of Cu in Sn were used to extract values for the effective charge, z *, that governs the electromigration of Cu. The calculated value of z * is significantly larger for current perpendicular to the c-axis than along it.

Exposure to Sarcocystis spp. in horses from Spain determined by Western blot analysis using Sarcocystis neurona merozoites as heterologous antigen.

PubMed

Arias, M; Yeargan, M; Francisco, I; Dangoudoubiyam, S; Becerra, P; Francisco, R; Sánchez-Andrade, R; Paz-Silva, A; Howe, D K

2012-04-30

Horses serve as an intermediate host for several species of Sarcocystis, all of which utilize canids as the definitive host. Sarcocystis spp. infection and formation of latent sarcocysts in horses often appears to be subclinical, but morbidity can occur, especially when the parasite burden is large. A serological survey was conducted to determine the presence of antibodies against Sarcocystis spp. in seemingly healthy horses from the Galicia region of Spain. Western blot analyses using Sarcocystis neurona merozoites as heterologous antigen suggested greater than 80% seroprevalance of Sarcocystis spp. in a sample set of 138 horses. The serum samples were further tested with enzyme-linked immunosorbent assays (ELISAs) based on recombinant S. neurona-specific surface antigens (rSnSAGs). As expected for horses from the Eastern Hemisphere, less than 4% of the serum samples were positive when analyzed with either the rSnSAG2 or the rSnSAG4/3 ELISAs. An additional 246 horses were tested using the rSnSAG2 ELISA, which revealed that less than 3% of the 384 samples were seropositive. Collectively, the results of this serologic study suggested that a large proportion of horses from this region of Spain are exposed to Sarcocystis spp. Furthermore, the anti-Sarcocystis seroreactivity in these European horses could be clearly distinguished from anti-S. neurona antibodies using the rSnSAG2 and rSnSAG4/3 ELISAs. Copyright © 2011 Elsevier B.V. All rights reserved.

Palladium and palladium-tin supported on multi wall carbon nanotubes or carbon for alkaline direct ethanol fuel cell

NASA Astrophysics Data System (ADS)

Geraldes, Adriana Napoleão; Furtunato da Silva, Dionisio; Martins da Silva, Júlio César; Antonio de Sá, Osvaldo; Spinacé, Estevam Vitório; Neto, Almir Oliveira; Coelho dos Santos, Mauro

2015-02-01

Pd and PdSn (Pd:Sn atomic ratios of 90:10), supported on Multi Wall Carbon Nanotubes (MWCNT) or Carbon (C), are prepared by an electron beam irradiation reduction method. The obtained materials are characterized by X-Ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), Transmission electron Microscopy (TEM) and Cyclic Voltammetry (CV). The activity for ethanol electro-oxidation is tested in alkaline medium, at room temperature, using Cyclic Voltammetry and Chronoamperometry (CA) and in a single alkaline direct ethanol fuel cell (ADEFC), in the temperature range of 60-90 °C. CV analysis finds that Pd/MWCNT and PdSn/MWCNT presents onset potentials changing to negative values and high current values, compared to Pd/C and PdSn/C electrocatalysts. ATR-FTIR analysis, performed during the CV, identifies acetate and acetaldehyde as principal products formed during the ethanol electro-oxidation, with low conversion to CO2. In single fuel cell tests, at 85 °C, using 2.0 mol L-1 ethanol in 2.0 mol L-1 KOH solutions, the electrocatalysts supported on MWCNT, also, show higher power densities, compared to the materials supported on carbon: PdSn/MWCNT, presents the best result (36 mW cm-2). The results show that the use of MWCNT, instead of carbon, as support, plus the addition of small amounts of Sn to Pd, improves the electrocatalytic activity for Ethanol Oxidation Reaction (EOR).

Potential risk assessment in stream sediments, soils and waters after remediation in an abandoned W>Sn mine (NE Portugal).

PubMed

Antunes, I M H R; Gomes, M E P; Neiva, A M R; Carvalho, P C S; Santos, A C T

2016-11-01

The mining complex of Murçós belongs to the Terras de Cavaleiros Geopark, located in Trás-os-Montes region, northeast Portugal. A stockwork of NW-SE-trending W>Sn quartz veins intruded Silurian metamorphic rocks and a Variscan biotite granite. The mineralized veins contain mainly quartz, cassiterite, wolframite, scheelite, arsenopyrite, pyrite, sphalerite, chalcopyrite, galena, rare pyrrhotite, stannite, native bismuth and also later bismuthinite, matildite, joseite, roosveltite, anglesite, scorodite, zavaritskite and covellite. The exploitation produced 335t of a concentrate with 70% of W and 150t of another concentrate with 70% of Sn between 1948 and 1976. The exploitation took place mainly in four open pit mines as well as underground. Three lakes were left in the area. Remediation processes of confination and control of tailings and rejected materials and phytoremediation with macrophytes from three lakes were carried out between 2005 and 2007. Stream sediments, soils and water samples were collected in 2008 and 2009, after the remediation process. Most stream sediments showed deficiency or minimum enrichment for metals. The sequential enrichment factor in stream sediments W>Bi>As>U>Cd>Sn=Ag>Cu>Sb>Pb>Be>Zn is mainly associated with the W>Sn mineralizations. Stream sediments receiving drainage of a mine dump were found to be significantly to extremely enriched with W, while stream sediments and soils were found to be contaminated with As. Two soil samples collected around mine dumps and an open pit lake were also found to be contaminated with U. The waters from the Murçós W>Sn mine area were acidic to neutral. After the remediation, the surface waters were contaminated with F(-), Al, As, Mn and Ni and must not be used for human consumption, while open pit lake waters must also not be used for agriculture because of contamination with F(-), Al, Mn and Ni. In most waters, the As occurred as As (III), which is toxic and is easily mobilized in the drainage system. The remediation promoted a decrease in metals and As concentrations of soils and waters, however the applied processes were not enough to rehabilitate the area. Copyright © 2016 Elsevier Inc. All rights reserved.

The nuclear cap-binding complex interacts with the U4/U6·U5 tri-snRNP and promotes spliceosome assembly in mammalian cells

PubMed Central

Pabis, Marta; Neufeld, Noa; Steiner, Michaela C.; Bojic, Teodora; Shav-Tal, Yaron; Neugebauer, Karla M.

2013-01-01

The nuclear cap-binding complex (CBC) binds to the 7-methyl guanosine cap present on every RNA polymerase II transcript. CBC has been implicated in many aspects of RNA biogenesis; in addition to roles in miRNA biogenesis, nonsense-mediated decay, 3′-end formation, and snRNA export from the nucleus, CBC promotes pre-mRNA splicing. An unresolved question is how CBC participates in splicing. To investigate CBC’s role in splicing, we used mass spectrometry to identify proteins that copurify with mammalian CBC. Numerous components of spliceosomal snRNPs were specifically detected. Among these, three U4/U6·U5 snRNP proteins (hBrr2, hPrp4, and hPrp31) copurified with CBC in an RNA-independent fashion, suggesting that a significant fraction of CBC forms a complex with the U4/U6·U5 snRNP and that the activity of CBC might be associated with snRNP recruitment to pre-mRNA. To test this possibility, CBC was depleted from HeLa cells by RNAi. Chromatin immunoprecipitation and live-cell imaging assays revealed decreased cotranscriptional accumulation of U4/U6·U5 snRNPs on active transcription units, consistent with a requirement for CBC in cotranscriptional spliceosome assembly. Surprisingly, recruitment of U1 and U2 snRNPs was also affected, indicating that RNA-mediated interactions between CBC and snRNPs contribute to splicing. On the other hand, CBC depletion did not impair snRNP biogenesis, ruling out the possibility that decreased snRNP recruitment was due to changes in nuclear snRNP concentration. Taken together, the data support a model whereby CBC promotes pre-mRNA splicing through a network of interactions with and among spliceosomal snRNPs during cotranscriptional spliceosome assembly. PMID:23793891

Two Years and Five Images of Supernova Refsdal

NASA Astrophysics Data System (ADS)

Kelly, Patrick

2017-01-01

In 1964, Sjur Refsdal hypothesized that a supernova (SN) whose light takes multiple paths to reach us around a strong gravitational lens could be used as a highly powerful probe. For such a system, the time delays between the images of the SN should depend sensitively on the cosmic expansion rate and the distribution of matter within the lens. I will present observations of the first strongly lensed SN resolved into multiple images, which was found in near-infrared imaging taken in early November 2014 with the Hubble Space Telescope (HST). SN `Refsdal' appeared in an Einstein cross configuration around an early-type galaxy in the MACS J1149.6+2223 cluster (z=0.54), and its light curve and spectrum are broadly similar to those of the peculiar and well-studied SN 1987A. Models of the cluster potential predicted that the SN would reappear within two years in a different image of its spiral host galaxy (z=1.49) closer to the cluster's center. In early December 2015, we detected the new image of the SN with the HST, and we anticipate being able to measure its relative time delay with a 1-2% precision, providing a rare test of blind model predictions.

Analysis of Nb 3Sn surface layers for superconducting radio frequency cavity applications

DOE PAGES

Becker, Chaoyue; Posen, Sam; Groll, Nickolas; ...

2015-02-23

Here, we present an analysis of Nb 3Sn surface layers grown on a bulk Nb coupon prepared at the same time and by the same vapor diffusion process used to make Nb 3Sn coatings on 1.3 GHz Nb cavities. Tunneling spectroscopy reveal a well developed, homogeneous superconducting density of states at the surface with a gap value distribution centered around 2.7 ± 0.4 meV and superconducting critical temperature's (T c) up to 16.3K. Transmission electron microscopy (TEM) performed on cross sections of the sample's surface shows a ~ 2 microns thick Nb 3Sn surface layer. The elemental composition map exhibitsmore » a Nb:Sn ratio of 3:1 with buried substoichiometric regions with a ratio of 5:1. Synchrotron diffraction experiments indicate a polycrystalline Nb 3Sn film and confirm the presence of Nb rich regions that occupies about a third of the coating volume. These low T c regions could play an important role in the dissipation mechanisms occurring during RF tests of Nb 3Sn -coated Nb cavities and open the way for further improving a very promising alternative to pure Nb cavities for particle accelerators.« less

The Effects of Antimony Addition on the Microstructural, Mechanical, and Thermal Properties of Sn-3.0Ag-0.5Cu Solder Alloy

NASA Astrophysics Data System (ADS)

Sungkhaphaitoon, Phairote; Plookphol, Thawatchai

2018-02-01

In this study, we investigated the effects produced by the addition of antimony (Sb) to Sn-3.0Ag-0.5Cu-based solder alloys. Our focus was the alloys' microstructural, mechanical, and thermal properties. We evaluated the effects by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), and a universal testing machine (UTM). The results showed that a part of the Sb was dissolved in the Sn matrix phase, and the remaining one participated in the formation of intermetallic compounds (IMCs) of Ag3(Sn,Sb) and Cu6(Sn,Sb)5. In the alloy containing the highest wt pct Sb, the added component resulted in the formation of SnSb compound and small particle pinning of Ag3(Sn,Sb) along the grain boundary of the IMCs. Our tests of the Sn-3.0Ag-0.5Cu solder alloys' mechanical properties showed that the effects produced by the addition of Sb varied as a function of the wt pct Sb content. The ultimate tensile strength (UTS) increased from 29.21 to a maximum value of 40.44 MPa, but the pct elongation (pct EL) decreased from 48.0 to a minimum 25.43 pct. Principally, the alloys containing Sb had higher UTS and lower pct EL than Sb-free solder alloys due to the strengthening effects of solid solution and second-phase dispersion. Thermal analysis showed that the alloys containing Sb had a slightly higher melting point and that the addition amount ranging from 0.5 to 3.0 wt pct Sb did not significantly change the solidus and liquidus temperatures compared with the Sb-free solder alloys. Thus, the optimal concentration of Sb in the alloys was 3.0 wt pct because the microstructure and the ultimate tensile strength of the SAC305 solder alloys were improved.

Light Echoes and the Progenitor of SN 2016adj in Cen A

NASA Astrophysics Data System (ADS)

Sugerman, Ben; Lawrence, Stephen

2016-02-01

The Type Ib/IIb supernova (SN) 2016adj is the fifth closest SN to be discovered during the lifetime of HST. This event offers us a rich variety of rare and unique opportunities, including: (1) identifying the progenitor; (2) mapping the three-dimensional structure and chemical composition of the progenitor's circumstellar and the host galaxy's interstellar environments; and (3) testing models of stellar mass loss and high-mass stellar evolution. The progenitor field of the SN has been observed from the near-UV to the mid-IR with HST and Spitzer, which will immediately allow us to accomplish the first science goal by identifying the progenitor (or establishing its upper limits) once new image with the SN present are taken with both observatories. Preliminary analyses of early-time spectra of SN 2016adj indicate its light is being extinguished by at least A(V)=2-4 magnitudes, meaning it is buried deep within the dust lane of Cen A. Echoes of the SN light off of this dust will allow us to produce high-resolution, three-dimensional maps of the structure and composition of the dust in and around the line-of-sight to the SN, which we will use to accomplish science goals (2)-(3) listed above. In particular, we will directly test the hypothesis that Type Ib/IIb SNe come not from very-high mass stars but from only moderately-massive stars that lost their envelopes to close binary companions. Please note that since echoes pass through a given point in space only once, data are permanently lost for each epoch that is not observed. While we will propose for continued observations in the Cycle 13 call for proposals, most of the science we propose cannot be achieved if the observations in this proposal are not taken before Cycle 13 begins.

[The application of subjective visual gravity in assessment of vestibular compensation: a pilot study].

PubMed

Zhao, Yuan; Chen, Taisheng; Wang, Wei; Xu, Kaixu; Wen, Chao; Liu, Qiang; Han, Xi; Li, Shanshan; Li, Xiaojie; Lin, Peng

2016-05-01

To discuss the characteristics of subjective visual gravity (subjective visual vertical/horizontal, SVV/SVH) and assess its clinical application for peripheral unilateral vestibular compensation. 69 cases of acute peripheral unilateral vestibular dysfunction patients (case group) accepted SVV/SVH, spontaneous nystagmus (SN), caloric test (CT) and other vestibular function tests. 49 healthy people (control group) accepted SVV/SVH only. SVV/SVH, SN and unilateral weakness (UW) were selected as for the observation indicators. The correlations between SVV/SVH, SN, UW and courses were investigated respectively, as well as the characteristic of SVV/SVH, SN in period of vestibular compensation. Among case group SVV, SVH positive in 42 patients(60.9%) and 44 patients(63.8%), the absolute values of the skew angle were in the range between 2.1°-20.0°, 2.1°-22.2°. Skew angles of SVV/SVH in control were in the range between -1.5°-2.0° and -2.0°-1.6°, and had no statistical significance with case group(t=5.336 and 5.864, P<0.05). SN-positive 28 cases (40.6%), the range of intensities at 2.4°-17.1°; UW-positive 50 cases (72.5%). In case group, positive correlation between SVV and SVH(r=0.948, P=0.00), negatively correlated between SVV/SVH and SN respectively(r values were -0.720, -0.733, P values were 0.00), no correlation between the skew angle of SVV/SVH, strength of SN and UW value(r values were 0.191, 0.189, and 0.179, P>0.05), there was no correlation between the absolute value of SVV, SVH, SN, UW with the duration (rs values were -0.075, -0.065, -0.212, and 0.126, P>0.05). Subjective visual gravity can be used not only to assess the range of unilateral peripheral vestibular dysfunction, but also help assess the static compensatory of otolithic, guidance and assessment of vestibular rehabilitation.

Electrochemical lithiation/delithiation of SnP₂O₇ observed by in situ XRD and ex situ⁷Li/³¹P NMR, and ¹¹⁹Sn Mössbauer spectroscopy.

PubMed

Bezza, Ilham; Kaus, Maximilian; Riekehr, Lars; Pfaffmann, Lukas; Doyle, Stephen; Indris, Sylvio; Ehrenberg, Helmut; Solhy, Abderrahim; Saadoune, Ismael

2016-04-21

SnP2O7 was prepared by a sol-gel route. The structural changes of tin pyrophosphate during the electrochemical lithiation were followed by using in situ XRD measurements that reveal the existence of a crystalline phase at the beginning of the discharge process. Nevertheless, it becomes amorphous after the full discharge as a result of a conversion reaction leading to the formation of LixSny alloys. The electrochemical tests show a high capacity with high retention upon cycling. To better understand the reaction mechanism of SnP2O7 with Li, several techniques were applied, such as ex situ(119)Sn Mössbauer and ex situ(7)Li and (31)P NMR spectroscopies with which we can follow the changes in the local environment of each element during cycling.

Two potential uses for silver nanoparticles coated with Solanum nigrum unripe fruit extract: Biofilm inhibition and photodegradation of dye effluent.

PubMed

Malaikozhundan, Balasubramanian; Vijayakumar, Sekar; Vaseeharan, Baskaralingam; Jenifer, Anthonisamy Anthoni; Chitra, Ponnaiah; Prabhu, Narayanan Marimuthu; Kannapiran, Ethiraj

2017-10-01

Silver nanoparticle was green synthesized involving the unripe fruit extracts of Solanum nigrum (Sn-AgNPs). The synthesized Sn-AgNPs was bio-physically characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). UV-Vis recorded the absorbance spectra at 443 nm. XRD analysis clearly demonstrated the crystalline nature of Sn-AgNPs with Bragg's reflection peaks at 111, 200, 220 and 311 lattice planes. The FTIR spectrum of Sn-AgNPs showed strong bands at 3432, 1555, 1455, 862 and 406 cm -1 which corresponds at O-H, C-H, C-C, C-OH and C-N groups respectively. TEM exhibited the spherical shape of Sn-AgNPs with particle size between 20 and 30 nm. The antibacterial effects of Sn-AgNPs were tested on clinically important biofilm forming Gram positive (Bacillus pumulis and Enterococcus faecalis) and Gram negative (Proteus vulgaris and Vibrio parahaemolyticus) bacteria. The greater inhibition of B. pumulis and E. faecalis was observed at 100 μg mL -1 of Sn-AgNPs compared to P. vulgaris and V. parahaemolyticus. The biofilm inhibition potential of Sn-AgNPs was greater against Gram positive bacteria than that of Gram negative bacteria. Furthermore, Sn-AgNPs effectively degraded the industrial effluent methyl orange dye by photocatalysis. It is concluded that Sn-AgNPs could be used as an effective therapeutics against the biofilm of clinically important bacteria. The green synthesized Sn-AgNPs can be employed to degrade dye effluents and prevent environmental pollution as well. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tin Sulfide Phase Exploration: Dependence of Optoelectronic Properties on Microstructural Growth and Chemical Variations in Thin Film Material

NASA Astrophysics Data System (ADS)

Banai, Rona Elinor

Herzenbergite tin (II) monosulfide (alpha-SnS) is of growing interest as a photovoltaic material because of its interesting optoelectronic properties and Earth abundance. It has several stable phases due to the dual valency of tin. As a layered material, alpha-SnS has the ability to form varying microstructure with differing properties. For this dissertation, films were RF sputtered from a SnS and SnS2 target to produce films with varying microstructure. Growth of high energy phases includin beta-SnS and amorphous SnS2 were possible through sputtering. Films of mixed or strained phase resulted from both targets. Pure phase alpha-SnS was made by annealing amorphous SnS2 films. Microstructure was measured using grazing incidence XRD and field emission SEM. The impact of microstructure was seen for both optical and electronic properties. Films were evaluated using spectroscopic ellipsometry as well as unpolarized UV-Vis transmission and reflection measurements. Optical modeling of the films is sufficient for developing models corresponding to specific microstructure, enabling it to be an inexpensive tool for studying the material. Absorption coefficient and band gap were also derived for these films. Films deposited with the SnS target had resistivity values up to 20,000 O-cm. Annealing of amorphous films deposited from the SnS2 target resulted in alpha-SnS films with much lower resistivity (<50 O-cm) values. This method for producing alpha-SnS offered better control of the phase, microstructure and therefore optoelectronic properties. While SnS films made from either target were typically p-type, sputtering of the SnS2 target with substrate heating resulted in n-type SnSx of a potentially new phase similar to SnS2 but with a 2:3 tin-to-sulfur ratio. Resistivity of those films typically ranged from 1 to 40 O-cm. Both p- and n-type films made from the SnS2 target had high carrier concentration of 10 17 to 1020 cm-3, but films had low Hall mobility such that conductivity type was not determined. Titanium, molybdenum, and aluminum contacts were tested for Ohmic and Schottky behavior using transmission line measurements. The complexity of its microstructure and flexibility in formation of varying phase and altered phase presents challenges to its use as a PV absorber.

Novel covariance-based neutrality test of time-series data reveals asymmetries in ecological and economic systems

DOE PAGES

Washburne, Alex D.; Burby, Joshua W.; Lacker, Daniel; ...

2016-09-30

Systems as diverse as the interacting species in a community, alleles at a genetic locus, and companies in a market are characterized by competition (over resources, space, capital, etc) and adaptation. Neutral theory, built around the hypothesis that individual performance is independent of group membership, has found utility across the disciplines of ecology, population genetics, and economics, both because of the success of the neutral hypothesis in predicting system properties and because deviations from these predictions provide information about the underlying dynamics. However, most tests of neutrality are weak, based on static system properties such as species-abundance distributions or themore » number of singletons in a sample. Time-series data provide a window onto a system’s dynamics, and should furnish tests of the neutral hypothesis that are more powerful to detect deviations from neutrality and more informative about to the type of competitive asymmetry that drives the deviation. Here, we present a neutrality test for time-series data. We apply this test to several microbial time-series and financial time-series and find that most of these systems are not neutral. Our test isolates the covariance structure of neutral competition, thus facilitating further exploration of the nature of asymmetry in the covariance structure of competitive systems. Much like neutrality tests from population genetics that use relative abundance distributions have enabled researchers to scan entire genomes for genes under selection, we anticipate our time-series test will be useful for quick significance tests of neutrality across a range of ecological, economic, and sociological systems for which time-series data are available. Here, future work can use our test to categorize and compare the dynamic fingerprints of particular competitive asymmetries (frequency dependence, volatility smiles, etc) to improve forecasting and management of complex adaptive systems.« less

Novel covariance-based neutrality test of time-series data reveals asymmetries in ecological and economic systems

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

Washburne, Alex D.; Burby, Joshua W.; Lacker, Daniel

Systems as diverse as the interacting species in a community, alleles at a genetic locus, and companies in a market are characterized by competition (over resources, space, capital, etc) and adaptation. Neutral theory, built around the hypothesis that individual performance is independent of group membership, has found utility across the disciplines of ecology, population genetics, and economics, both because of the success of the neutral hypothesis in predicting system properties and because deviations from these predictions provide information about the underlying dynamics. However, most tests of neutrality are weak, based on static system properties such as species-abundance distributions or themore » number of singletons in a sample. Time-series data provide a window onto a system’s dynamics, and should furnish tests of the neutral hypothesis that are more powerful to detect deviations from neutrality and more informative about to the type of competitive asymmetry that drives the deviation. Here, we present a neutrality test for time-series data. We apply this test to several microbial time-series and financial time-series and find that most of these systems are not neutral. Our test isolates the covariance structure of neutral competition, thus facilitating further exploration of the nature of asymmetry in the covariance structure of competitive systems. Much like neutrality tests from population genetics that use relative abundance distributions have enabled researchers to scan entire genomes for genes under selection, we anticipate our time-series test will be useful for quick significance tests of neutrality across a range of ecological, economic, and sociological systems for which time-series data are available. Here, future work can use our test to categorize and compare the dynamic fingerprints of particular competitive asymmetries (frequency dependence, volatility smiles, etc) to improve forecasting and management of complex adaptive systems.« less

Cadmium Alternatives: Zinc-Nickel Electroplating & Repair of Aluminum Coatings

DTIC Science & Technology

2008-02-27

Brighteners and Other Additives to Create Low Embrittling Plating Process • Based on Successful Test Results an LHE Alkaline Zn-Ni Formula was Selected for...Corrosion Testing (Salt Spray and Galvanic) – Fluid Immersion (ASTM F 483) Lubricity (Fasteners)– – Strippability • Ammonium Nitrate (pH 10...Considered – LDC 5030 Sn-Zn and SIFCO 4018 Zn-Ni • LDC 5030 Sn-Zn Selected Because of No-Bake Hydrogen Embrittlement Performance • Aluminum Surface

Microstructure and hot compression deformation of the as-cast Mg-5.0Sn-1.5Y-0.1Zr alloy

NASA Astrophysics Data System (ADS)

Luo, Xiaoping; Kang, Li; Li, Qiushu; Chai, Yuesheng

2015-08-01

The hot compression deformation behavior and microstructure of as-cast Mg-5.0Sn-1.5Y-0.1Zr alloy were investigated by performing isothermal hot compression tests. The tests were conducted using a thermal mechanical simulator at 250-450 °C and strain rates ranging from 0.002 to 2 s-1, with a maximum deformation strain of 50 %. The effects of the deformation parameters on the microstructure evolution of the Mg-5.0Sn-1.5Y-0.1Zr alloy were discussed. The study revealed the flow behavior and the deformation mechanism of the Mg-5.0Sn-1.5Y-0.1Zr alloy. The dependence of flow stress on temperature and strain rate was described by a hyperbolic sine constitutive equation. Through regression analysis, the activation energy of 223.26 kJ mol-1 for plastic deformation was determined by considering flow stress at a strain rate of 0.2. Microstructure observation showed that dynamic recrystallization occurred extensively along grain boundaries at temperatures higher than 300 °C and strain rates lower than 0.02 s-1. This observation provides a theoretical basis for the manufacture and application of the Mg-5.0Sn-1.5Y-0.1Zr alloy.

Differential expression of poplar sucrose nonfermenting1-related protein kinase 2 genes in response to abiotic stress and abscisic acid.

PubMed

Yu, Xiang; Takebayashi, Arika; Demura, Taku; Ohtani, Misato

2017-09-01

Knowledge on the responses of woody plants to abiotic stress can inform strategies to breed improved tree varieties and to manage tree species for environmental conservation and the production of lignocellulosic biomass. In this study, we examined the expression patterns of poplar (Populus trichocarpa) genes encoding members of the sucrose nonfermenting1-related protein kinase 2 (SnRK2) family, which are core components of the abiotic stress response. The P. trichocarpa genome contains twelve SnRK2 genes (PtSnRK2.1- PtSnRK2.12) that can be divided into three subclasses (I-III) based on the structures of their encoded kinase domains. We found that PtSnRK2s are differentially expressed in various organs. In MS medium-grown plants, all of the PtSnRK2 genes were significantly upregulated in response to abscisic acid (ABA) treatment, whereas osmotic and salt stress treatments induced only some (four and seven, respectively) of the PtSnRK2 genes. By contrast, soil-grown plants showed increased expression of most PtSnRK2 genes under drought and salt treatments, but not under ABA treatment. In soil-grown plants, drought stress induced SnRK2 subclass II genes in all tested organs (leaves, stems, and roots), whereas subclass III genes tended to be upregulated in leaves only. These results suggest that the PtSnRK2 genes are involved in abiotic stress responses, are at least partially activated by ABA, and show organ-specific responses.

Expression of a potato antimicrobial peptide SN1 increases resistance to take-all pathogen Gaeumannomyces graminis var. tritici in transgenic wheat.

PubMed

Rong, Wei; Qi, Lin; Wang, Jingfen; Du, Lipu; Xu, Huijun; Wang, Aiyun; Zhang, Zengyan

2013-08-01

Take-all, caused by soil-borne fungus Gaeumannomyces graminis var. tritici (Ggt), is a devastating root disease of wheat (Triticum aestivum) worldwide. Breeding resistant wheat cultivars is the most promising and reliable approach to protect wheat from take-all. Currently, no resistant wheat germplasm is available to breed cultivars using traditional methods. In this study, gene transformation was carried out using Snakin-1 (SN1) gene isolated from potato (Solanum tuberosum) because the peptide shows broad-spectrum antimicrobial activity in vitro. Purified SN1 peptide also inhibits in vitro the growth of Ggt mycelia. By bombardment-mediated method, the gene SN1 was transformed into Chinese wheat cultivar Yangmai 18 to generate SN1 transgenic wheat lines, which were used to assess the effectiveness of the SN1 peptide in protecting wheat from Ggt. Genomic PCR and Southern blot analyses indicated that the alien gene SN1 was integrated into the genomes of five transgenic wheat lines and heritable from T₀ to T₄ progeny. Reverse transcription-PCR and Western blot analyses showed that the introduced SN1 gene was transcribed and highly expressed in the five transgenic wheat lines. Following challenging with Ggt, disease test results showed that compared to segregants lacking the transgene and untransformed wheat plants, these five transgenic wheat lines expressing SN1 displayed significantly enhanced resistance to take-all. These results suggest that SN1 may be a potentially transgenic tool for improving the take-all resistance of wheat.

Improved electrochemical performances of LiSn2(PO4)3 anode material for lithium-ion battery prepared by solid-state method

NASA Astrophysics Data System (ADS)

Naren; Tian, Jianhua; Wang, Dongdong; Shan, Zhongqiang

2017-09-01

The rhombohedral LiSn2(PO4)3 was prepared by solid-state method for the anode material of lithium-ion battery. The effect of pH value of hydrothermal reaction system on the morphology of SnO2 as the precursor of LiSn2(PO4)3 and the influence of heat-treatment procedure and conditions, such as the sintering temperature and time, on the property of LiSn2(PO4)3 were investigated. The purity, morphology, structure and size distribution of prepared LiSn2(PO4)3 were characterized respectively by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) methods. The results demonstrate that the as-prepared LiSn2(PO4)3 particles exhibit rhombohedral single-crystal structure with an average particle size of 200 nm. The electrochemical measurement results reveal that the as-prepared LiSn2(PO4)3/C electrode exhibits the improved cycling stability and reversibility with a reversible discharge capacity of 448.6 mA h g-1 at 100 mA g-1 and better rate capability of 332.6 mA h g-1 at 500 mA g-1. The charge-discharge mechanism of LiSn2(PO4)3/C electrode was also investigated. According to the test results of cyclic voltammetry, the electrode process includes not only the intercalation and deintercalation of lithium ions in the LiSn2(PO4)3 particles, but also the surface pseudo-capacitive effect.

Enhanced photo-, sono- and sonophotocatalysis of methylene blue via SnO2 nanoparticle supported on nanographene platelets (NGP)

NASA Astrophysics Data System (ADS)

Paramarta, V.; Taufik, A.; Saleh, R.

2017-07-01

In our previous study, we have reported the catalytic (photo- and sono-) performance of SnO2 nanoparticles in methylene blue (MB) removal from aqueous solution. In this study, SnO2/nanographene platelets (NGP) composites were fabricated by depositing SnO2 nanoparticle onto nanographene platelets surface to develop photo-, sono-, and sonophotocatalysts, SnO2 nanoparticle, and SnO2/NGP composites were successfully synthesized using the sol-gel and coprecipitation method, respectively. The nanographene platelets (NGP) content was varied from 5, 10, and 15 weight percentages (wt.%). The optical properties and thermal stability of the samples were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and Thermal Gravimetric Analysis (TGA). The catalytic ability of the samples was investigated using photo-, sono-, and sonophoto degradation of MB which was observed when nanographene platelets (NGP) were added into SnO2 nanocomposite. The photo-, sono- and sonophotocatalytic activities of SnO2/NGP composites on dyes were analyzed by measuring the change in absorbance of dyes under UV-spectrophotometer. The degradation of the organic dyes has been calculated by monitoring the degradation in concentration of the dyes before and after irradiation of UV light, ultrasound, and both of them respectively. The influence of other parameters such as catalyst dosage, pH, and scavenger have also been investigated. The results showed that SnO2/NGP composite with 10 weight percent (wt.%) has better catalytic performance than pure SnO2 nanoparticle. The reusability tests have also been done to ensure the stability of the used catalysts.

Cross-cultural adaptation and validation of the Sinus and Nasal Quality of Life Survey (SN-5) into Brazilian Portuguese.

PubMed

Uchoa, Priscila Regina Candido Espinola; Bezerra, Thiago Freire Pinto; Lima, Élcio Duarte; Fornazieri, Marco Aurélio; Pinna, Fabio de Rezende; Sperandio, Fabiana de Araújo; Voegels, Richard Louis

The concept of quality of life is subjective and variable definition, which depends on the individual's perception of their state of health. Quality of life questionnaires are instruments designed to measure quality of life, but most are developed in a language other than Portuguese. Questionnaires can identify the most important symptoms, focus on consultation, and assist in defining the goals of treatment. Some of these have been validated for the Portuguese language, but none in children. To validate the translation with cross-cultural adaptation and validation of the Sinus and Nasal Quality of Life Survey (SN-5) into Portuguese. Prospective study of children aged 2-12 years with sinonasal symptoms of over 30 days. The study comprised two stages: (I) translation and cross-cultural adaptation of the SN-5 into Portuguese (SN-5p); and (II) validation of the SN5-p. Statistical analysis was performed to assess internal consistency, test-retest reliability, and sensitivity, as well as construct and discriminant validity and standardization. The SN-5 was translated and adapted into Portuguese (SN-5p) and the author of the original version approved the process. Validation was carried out by administration of the SN-5p to 51 pediatric patients with sinonasal complaints (mean age, 5.8±2.5 years; range, 2-12 years). The questionnaire exhibited adequate construct validity (0.62, p<0.01), internal consistency (Cronbach's alpha=0.73), and discriminant validity (p<0.01), as well as good test-retest reproducibility (Goodman-Kruskal gamma=0.957, p<0.001), good correlation with a visual analog scale (r=0.62, p<0.01), and sensitivity to change. This study reports the successful translation and cross-cultural adaptation of the SN-5 instrument into Brazilian Portuguese. The translated version exhibited adequate psychometric properties for assessment of disease-specific quality of life in pediatric patients with sinonasal complaints. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

SnO2 quantum dots decorated on RGO: a superior sensitive, selective and reproducible performance for a H2 and LPG sensor

NASA Astrophysics Data System (ADS)

Mishra, R. K.; Upadhyay, S. B.; Kushwaha, Ajay; Kim, Tae-Hyung; Murali, G.; Verma, Ranjana; Srivastava, Manish; Singh, Jay; Sahay, P. P.; Hee Lee, Seung

2015-07-01

We report the H2 and LPG gas sensing behavior of RGO/SnO2 QDs synthesized by a surfactant assisted hydrothermal method. The RGO/SnO2 QD based sensor shows a high response of ~89.3% to H2 and ~92.4% to LPG for 500 ppm test gas concentration at operating temperatures of 200 °C and 250 °C, respectively. Further, the RGO/SnO2 QD based sensor shows good selectivity for H2 and LPG in the presence of other interfering gases such as ammonia, chloroform, toluene, benzene, acetone, n-butylacetate, acetic acid and formic acid. We observed that the gas response to H2 is 29.8 times higher than that to acetic acid whereas the gas response to LPG is 17.8 times higher than that to formic acid. Long-term analyses have also been performed to demonstrate the reproducible nature of the RGO/SnO2 QD based sensor over passing time which shows excellent reproducibility.We report the H2 and LPG gas sensing behavior of RGO/SnO2 QDs synthesized by a surfactant assisted hydrothermal method. The RGO/SnO2 QD based sensor shows a high response of ~89.3% to H2 and ~92.4% to LPG for 500 ppm test gas concentration at operating temperatures of 200 °C and 250 °C, respectively. Further, the RGO/SnO2 QD based sensor shows good selectivity for H2 and LPG in the presence of other interfering gases such as ammonia, chloroform, toluene, benzene, acetone, n-butylacetate, acetic acid and formic acid. We observed that the gas response to H2 is 29.8 times higher than that to acetic acid whereas the gas response to LPG is 17.8 times higher than that to formic acid. Long-term analyses have also been performed to demonstrate the reproducible nature of the RGO/SnO2 QD based sensor over passing time which shows excellent reproducibility. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02837j

Irinotecan metabolite SN38 results in germ cell loss in the testis but not in the ovary of prepubertal mice.

PubMed

Lopes, Federica; Smith, Rowena; Nash, Sophie; Mitchell, Rod T; Spears, Norah

2016-11-01

Does the Irinotecan metabolite 7-ethyl-10-hydroxycamptothecan (SN38) damage the gonads of male and female prepubertal mice? The Irinotecan metabolite SN38 reduces germ cell numbers within the seminiferous tubules of mouse testes at concentrations that are relevant to cancer patients, while in contrast it has little if any effect on the female germ cell population. Little is known about the role of the chemotherapeutic agent Irinotecan on female fertility, with only one article to date reporting menopausal symptoms in perimenopausal women treated with Irinotecan, while no data are available either on adult male fertility or on the impact of Irinotecan on the subsequent fertility of prepubertal cancer patients, female or male. Male and female gonads were obtained from postnatal day 5 C57BL/6 mice and exposed in vitro to a range of concentrations of the Irinotecan metabolite SN38: 0.002, 0.01, 0.05, 0.1 or 1 µg ml -1 for the testis and 0.1, 1, 2.5 or 5 µg ml -1 for the ovary, with treated gonads compared to control gonads not exposed to SN38. SN38 was dissolved in 0.5% dimethyl sulfoxide, with controls exposed to the same concentration of diluent. The number of testis fragments used for each analysis ranged between 3 and 9 per treatment group, while the number of ovaries used for each analysis ranged between 4 and 12 per treatment group. Neonatal mouse gonads were developed in vitro, with tissue analysed at the end of the 4-6 day culture period, following immunofluorescence or hematoxylin and eosin staining. Statistical analyses were performed using one-way ANOVA followed by Bonferroni post-hoc test for normally distributed data and Kruskal-Wallis test followed by Dunns post-test for non-parametric data. Abnormal testis morphology was observed when tissues were exposed to SN38, with a smaller seminiferous tubule diameter at the highest concentration of SN38 (1 µg ml -1 , p < 0.001 versus control) and increased number of Sertoli cell-only tubules at the two highest concentrations of SN38 (0.1 µg ml -1 , p < 0.001; 1 µg ml -1 , p < 0.0001, both versus control). Within seminiferous tubules, a dose response decrease was observed in both germ cell number (mouse vasa homologue (MVH)-positive cells) and in proliferating cell number (bromodeoxyuridine (BrdU)-positive cells), with significance reached at the two highest concentrations of SN38 (0.1 µg ml -1 , p < 0.01 for both; 1 µg ml -1 , p < 0.001-MVH, p < 0.01-BrdU; all versus control). No change was seen in protein expression of the apoptotic marker cleaved caspase 3. Double immunofluorescence showed that occasional proliferating germ cells were present in treated testes, even after exposure to the highest drug concentration. When prepubertal ovaries were treated with SN38, no effect was seen on germ cell number, apoptosis or cell proliferation, even after exposure to the highest drug concentrations. As with any study using in vitro experiments with an experimental animal model, caution is required when extrapolating the present findings to humans. Differences between human and mouse spermatogonial development also need to be considered when assessing the effect of chemotherapeutic exposure. However, the prepubertal testes and ovaries used in the present studies contain germ cell populations that are representative of those found in prepubertal patients, and experimental tissues were exposed to drug concentrations within the range found in patient plasma. Our findings demonstrate that the prepubertal mouse ovary is relatively insensitive to exposure to the Irinotecan metabolite SN38, while it induces a marked dose-dependent sensitivity in the testicular germ cell population. The study identifies the importance of further investigation to identify the risk of infertility in young male cancer patients treated with Irinotecan. None. Work supported by Medical Research Grant (MRC) grant G1002118 and Children with Cancer UK grant 15-198. The authors declare that there is no conflict of interest that could prejudice the impartiality of the present research. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology.

Free-standing anode of N-doped carbon nanofibers containing SnO{sub x} for high-performance lithium batteries

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

Zou, Mingzhong; Li, Jiaxin, E-mail: ljx3012982@yahoo.com; Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002

2014-12-15

Highlights: • Self-standing SnO{sub x} N-CNF electrodes were synthesized by electrospinning. • The SnO{sub x} N-CNFs anode exhibits high capacity, good cyclic stability, and excellent rate performance for lithium ion batteries. • The enhanced performance is ascribed to the synergetic effects between N-CNFs and SnO{sub x} nanoparticles. - Abstract: Free-standing paper of N-doped carbon nanofibers (NCNFs) containing SnO{sub x} was prepared by electrospinning. The structure and morphology of the sample were analyzed by XRD, XPS, SEM, and TEM. The results show that nitrogen atoms were successfully doped into CNFs. The SnO{sub x} were homogenously embedded in the N-doped CNFs viamore » annealing treatment. Subsequently, the SnO{sub x} NCNF paper was cut into disks and used as anodes for lithium ion batteries (LIBs). The anodes of SnO{sub x} NCNFs exhibit excellent cycling stability and show high capacity of 520 mA h g{sup −1} tested at a 200 mA g{sup −1} after 100 cycles. More importantly, at a high current density of 500 mA g{sup −1}, a large reversible capacity of 430 mA h g{sup −1} after 100 cycles can still be obtained. The good electrochemical performance should be attributed to the good electronic conductivity from the NCNFs and the synergistic effects from NCNFs and SnO{sub x} materials.« less

Bentonite modification with pillarization method using metal stannum

NASA Astrophysics Data System (ADS)

Widjaya, Robert R.; Juwono, Ariadne L.; Rinaldi, Nino

2017-11-01

Clay minerals have received considerable attention in the last years because of their environmental compatibility, low cost, high selectivity, and operational simplicity. Although clays are very useful for many application in the field of catalysis, they have main disadvantage: their lack of pore volume and spesific surface area. Porosity and stability of these materials are improved by pillaring the clay layers with SnCl4, which leads to materials known as pillared clays (PILC). This research aims were to characterize the Bentonite and Sn-Bentonite as catalysts for cracking and oligomerization. The Sn-Bentonite was prepared by pillarization method with a variation in metal ratio of 5 mmol dan 10 mmol.gr-1 of bentonit. The catalyst characterized by X-ray Diffraction, X-ray Fluorescence, Fourier Transform Infra Red, Brunauer Emmett Teller, Thermogravimetric Analysis. The results showed that the Sn-Bentonite catalyst had large basal spacing and good porous structure, and the specific surface areas increased. XRF detected the Sn in the Bentonite and TGA results showed the ability Sn-Bentonite in receiving heat. FTIR test showed two type of acidity, broansted and lewis acid. The characterized results indicated that Sn-Bentonite with metal ratio 5 mmol.gr-1 better than Sn-Bentonite with metal ratio 10 mmol.gr-1, in which there was a significant increase the basal spacings, specific surface area, and pore volume. The TGA results for Sn-Bentonite appeared to be more thermally stable than Bentonite.

The effect of weld porosity on the cryogenic fatigue strength of ELI grade Ti-5Al-2.5Sn

NASA Technical Reports Server (NTRS)

Rogers, P. R.; Lambdin, R. C.; Fox, D. E.

1992-01-01

The effect of weld porosity on the fatigue strength of ELI grade Ti-5Al-2.5Sn at cryogenic temperature was determined. A series of high cycle fatigue (HCF) and tensile tests were performed at -320 F on specimens made from welded sheets of the material. All specimens were tested with weld beads intact and some amount of weld offset. Specimens containing porosity and control specimens containing no porosity were tested. Results indicate that for the weld configuration tested, the fatigue life of the material is not affected by the presence of spherical embedded pores.

High-performance tin oxide-nitrogen doped graphene aerogel hybrids as anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Tan, Chunhui; Cao, Jing; Khattak, Abdul Muqsit; Cai, Feipeng; Jiang, Bo; Yang, Gai; Hu, Suqin

2014-12-01

Tin dioxide nanoparticles on nitrogen doped graphene aerogel (SnO2-NGA) hybrid are synthesized by one-step hydrothermal method and successfully applied in lithium-ion batteries as a free-standing anode. The electrochemical performance of SnO2-NGA hybrid is investigated by galvanostatic charge-discharge cycling, rate capability test, cyclic voltammetry and electrochemical impedance spectroscopy. It is found that the SnO2-NGA hybrid with freestanding spongy-like structure exhibit remarkable lithium storage capacity (1100 mAh g-1 after 100 cycles), good cycling stability and high rate capability. The outstanding performance is attributed to the uniform SnO2 nanoparticles, unique spongy-like structure and N doping defect for Li+ diffusion.

Birth of a Pulsar Wind Nebula in SN 1970G

NASA Astrophysics Data System (ADS)

Milisavljevic, Dan

2016-09-01

Chandra observations of the Type IIL supernova SN1970G obtained in 2011 showed a dramatic re-brightening in its X-ray luminosity. This sudden change contrasted starkly with radio emissions that have declined in strength throughout the supernova's lifetime. We request a modest investment of Chandra time to test our hypothesis that this combination of emission properties is associated with a newly formed pulsar wind nebula. We also request three hours of VLA time to look for possible late-time SN-CSM interaction and to fully characterize the nature of the emission.

Extreme Doppler Shifting of Io's Neutral Jets

NASA Astrophysics Data System (ADS)

Schmidt, Carl

2017-08-01

The dynamics and the extension of Jupiter's magnetosphere are determined by the massive internal plasma sources combined with the fast rotation. The vast majority of the plasma originates from the atmosphere of the moon Io, the most volcanically active body in our solar system. Here we propose to characterize the density and velocity of energetic neutral atoms escaping from Io's atmosphere. Exploiting the high resolution and sensitivity of the COS G130M spectral mode, we will measure the Doppler velocities of atomic O, S and Cl streams, which are energized through charge exchange and dissociative recombination of molecular ions. Prior COS observations of Io revealed a large number of emission lines from several ion and neutral species with excellent S/N, obtained over a single HST orbit. Those spectra were obtained surrounding eclipse geometry, where Doppler shifts are minimized and were restricted to Io itself rather than the stream region. Here we will target the extended clouds with only two orbits total when the moon is at eastern and western elongation for maximum Doppler shifts. The observations will provide new constraints on the diffuse large-scale cloud structures in the Jovian system and significantly improve our understanding of the transport of mass and energy within the Io-torus interaction. The absolute brightness, in combination with plasma parameters from line ratios/collision strengths, will allow us to quantify the outflow of energetic neutral atoms from Io's main sulfur-oxygen atmosphere for the first time.

Innovative approach for the valorization of useful metals from waste electric and electronic equipment (WEEE)

NASA Astrophysics Data System (ADS)

Soare, V.; Burada, M.; Dumitrescu, D. V.; Constantin, I.; Soare, V.; Popescu, A.-M. J.; Carcea, I.

2016-08-01

Waste electric and electronic equipment are an important secondary source of rare and precious metals and their processing through ecological technologies constitutes a major concern in the European Union and significantly contributes to the reduction of environmental pollution and to the preservation of valuable resources of nonferrous metals. The paper presents an innovative approach for the complex valorization of useful metals contained in WEEE. The method consists in the melting of WEEE in a furnace in a microwave field at temperatures of 1000 ÷1200°C, for the complete separation of the metallic fraction from the organic components. The gases resulting from the melting process were also treated/neutralized in a microwave environment and the obtained metallic bulk (multi-component alloy) was processed through combined hydrometallurgical and electrochemical methods. The major elements in the metallic bulk (Cu, Sn, Zn, Pb) were separated/recovered by anodic dissolution, respectively by leaching in nitric acid followed by cementation using various agents, or by electrodeposition. Depending on the electrochemical parameters, cathodic deposits consisting of Cu, with a purity higher than 99.9%, or of Cu-Sn and Cu-Sn-Zn alloys were obtained. Silver was valorized by leaching/precipitation with NaCl and the gold concentrated in the anodic slime will be recovered by thiourea extraction. The experiments performed demonstrate the possibility of ecological and efficient processing of WEEE in a microwave field and the recovery of nonferrous and precious metals through combined hydrometallurgical and electrochemical methods.

Optical and UV Spectra of the Remnant of SN 1885 (S And) in M31

NASA Astrophysics Data System (ADS)

Fesen, Robert A.; Weil, Kathryn E.; Hamilton, Andrew J. S.; Höflich, Peter A.

2017-10-01

We present multi-slit, 1D and 2D optical and UV spectra of the remnant of supernova 1885 (SN 1885; S And) taken using the Hubble Space Telescope’s Imaging Spectrograph (HST/STIS). These spectra of this probable subluminous Type Ia remnant, seen in silhouette against the central bulge of the Andromeda galaxy (M31), show strong and broad absorptions from neutral and singly ionized species of calcium, magnesium, and iron but with strikingly different distributions. Calcium H and K absorption indicates spherically distributed Ca-rich ejecta, densest in a lumpy shell expanding at 2000-6000 km s-1. Equally broad but weaker Ca I 4227 Å absorption is seen to extend out to velocities of ˜13,000 km s-1. Magnesium-rich ejecta in the remnant are detected for the first time through Mg I 2852 Å and Mg II 2796, 2803 Å absorptions concentrated in a shell with expansion velocities from ≃ 7000 {km} {{{s}}}-1 to at least 10,000 km s-1. Fe I 3720 Å absorption is detected as two discrete blueshifted and redshifted absorptions suggestive of an Fe I shell with expansion velocities of ±2000-8000 km s-1. Weak Fe II resonance absorptions in the wavelength region 2300-2700 Å are consistent with prior HST UV images showing Fe II-rich ejecta confined to a small number of optically thick plumes. The presence of such iron plumes extending out from the remnant’s core plus layered shells of calcium and magnesium point to a delayed-detonation explosion. The spectra also suggest a roughly spherical explosion, contrary to that expected by a merger or collision of two white dwarfs. We conclude that SN 1885 likely was an off-center, delayed-detonation explosion leading to a subluminous SN Ia similar to SN 1986G. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract No. NAS5-26555.

Nanosized thin SnO₂ layers doped with Te and TeO₂ as room temperature humidity sensors.

PubMed

Georgieva, Biliana; Podolesheva, Irena; Spasov, Georgy; Pirov, Jordan

2014-05-21

In this paper the humidity sensing properties of layers prepared by a new method for obtaining doped tin oxide are studied. Different techniques-SEM, EDS in SEM, TEM, SAED, AES and electrical measurements-are used for detailed characterization of the thin layers. The as-deposited layers are amorphous with great specific area and low density. They are built up of a fine grained matrix, consisting of Sn- and Te-oxides, and a nanosized dispersed phase of Te, Sn and/or SnTe. The chemical composition of both the matrix and the nanosized particles depends on the ratio R(Sn/Te) and the evaporation conditions. It is shown that as-deposited layers with R(Sn/Te) ranging from 0.4 to 0.9 exhibit excellent characteristics as humidity sensors operating at room temperature-very high sensitivity, good selectivity, fast response and short recovery period. Ageing tests have shown that the layers possess good long-term stability. Results obtained regarding the type of the water adsorption on the layers' surface help better understand the relation between preparation conditions, structure, composition and humidity sensing properties.

Application of Taguchi approach to optimize the sol-gel process of the quaternary Cu2ZnSnS4 with good optical properties

NASA Astrophysics Data System (ADS)

Nkuissi Tchognia, Joël Hervé; Hartiti, Bouchaib; Ridah, Abderraouf; Ndjaka, Jean-Marie; Thevenin, Philippe

2016-07-01

Present research deals with the optimal deposition parameters configuration for the synthesis of Cu2ZnSnS4 (CZTS) thin films using the sol-gel method associated to spin coating on ordinary glass substrates without sulfurization. The Taguchi design with a L9 (34) orthogonal array, a signal-to-noise (S/N) ratio and an analysis of variance (ANOVA) are used to optimize the performance characteristic (optical band gap) of CZTS thin films. Four deposition parameters called factors namely the annealing temperature, the annealing time, the ratios Cu/(Zn + Sn) and Zn/Sn were chosen. To conduct the tests using the Taguchi method, three levels were chosen for each factor. The effects of the deposition parameters on structural and optical properties are studied. The determination of the most significant factors of the deposition process on optical properties of as-prepared films is also done. The results showed that the significant parameters are Zn/Sn ratio and the annealing temperature by applying the Taguchi method.

Mode of action and membrane specificity of the antimicrobial peptide snakin-2

PubMed Central

Herbel, Vera

2016-01-01

Antimicrobial peptides (AMPs) are a diverse group of short, cationic peptides which are naturally occurring molecules in the first-line defense of most living organisms. They represent promising candidates for the treatment of pathogenic microorganisms. Snakin-2 (SN2) from tomato (Solanum lycopersicum) is stabilized through six intramolecular disulphide bridges; it shows broad-spectrum antimicrobial activity against bacteria and fungi, and it agglomerates single cells prior to killing. In this study, we further characterized SN2 by providing time-kill curves and corresponding growth inhibition analysis of model organisms, such as E. coli or B. subtilis. SN2 was produced recombinantly in E. coli with thioredoxin as fusion protein, which was removed after affinity purification by proteolytic digestion. Furthermore, the target specificity of SN2 was investigated by means of hemolysis and hemagglutination assays; its effect on plant cell membranes of isolated protoplasts was investigated by microscopy. SN2 shows a non-specific pore-forming effect in all tested membranes. We suggest that SN2 could be useful as a preservative agent to protect food, pharmaceuticals, or cosmetics from decomposition by microbes. PMID:27190708

Effects of Sn and Sb on the corrosion resistance of AH 32 steel in a cargo oil tank environment

NASA Astrophysics Data System (ADS)

Ahn, SooHoon; Park, Kyung Jin; Oh, KkochNim; Hwang, SungDoo; Park, ByungJoon; Kwon, HyukSang; Shon, MinYoung

2015-09-01

Effects of the alloying elements, Sn and Sb, on the corrosion resistance of modified AH 32 steel for the cargo oil tanks (COT) were examined using an electrochemical test and weight loss measurement. All experiments were carried out in acidic chloride solution (0.14 M HCl and 10 wt% NaCl, pH 0.85) at 30 °C, simulating the inner bottom plate of COT. It was clearly found that the small amount addition of Sn and Sb improved the corrosion resistance of modified AH 32 steel, which is confirmed by the higher polarization resistance of AH 32 steel modified with Sn and Sb addition compared with that of the base steel. X-ray photoelectron spectroscopy analysis of the corroded surface after immersion of 72 h presented that the AH 32 steel modified with Sn and Sb addition created the protective corrosion products including SnO2 and Sb2O5. These oxides act as high corrosion inhibitor to anodic corrosion reaction, and hence leading to the improvement in the corrosion resistance of the modified AH 32 steels.

Forced Ion Migration for Chalcogenide Phase Change Memory Device

NASA Technical Reports Server (NTRS)

Campbell, Kristy A (Inventor)

2013-01-01

Non-volatile memory devices with two stacked layers of chalcogenide materials comprising the active memory device have been investigated for their potential as phase-change memories. The devices tested included GeTe/SnTe, Ge2Se3/SnTe, and Ge2Se3/SnSe stacks. All devices exhibited resistance switching behavior. The polarity of the applied voltage with respect to the SnTe or SnSe layer was critical to the memory switching properties, due to the electric field induced movement of either Sn or Te into the Ge-chalcogenide layer. One embodiment of the invention is a device comprising a stack of chalcogenide-containing layers which exhibit phase-change switching only after a reverse polarity voltage potential is applied across the stack causing ion movement into an adjacent layer and thus "activating" the device to act as a phase-change random access memory device or a reconfigurable electronics device when the applied voltage potential is returned to the normal polarity. Another embodiment of the invention is a device that is capable of exhibiting more than two data states.

Forced ion migration for chalcogenide phase change memory device

NASA Technical Reports Server (NTRS)

Campbell, Kristy A. (Inventor)

2011-01-01

Non-volatile memory devices with two stacked layers of chalcogenide materials comprising the active memory device have been investigated for their potential as phase change memories. The devices tested included GeTe/SnTe, Ge.sub.2Se.sub.3/SnTe, and Ge.sub.2Se.sub.3/SnSe stacks. All devices exhibited resistance switching behavior. The polarity of the applied voltage with respect to the SnTe or SnSe layer was critical to the memory switching properties, due to the electric field induced movement of either Sn or Te into the Ge-chalcogenide layer. One embodiment of the invention is a device comprising a stack of chalcogenide-containing layers which exhibit phase change switching only after a reverse polarity voltage potential is applied across the stack causing ion movement into an adjacent layer and thus "activating" the device to act as a phase change random access memory device or a reconfigurable electronics device when the applied voltage potential is returned to the normal polarity. Another embodiment of the invention is a device that is capable of exhibiting more that two data states.

Forced ion migration for chalcogenide phase change memory device

NASA Technical Reports Server (NTRS)

Campbell, Kristy A. (Inventor)

2012-01-01

Non-volatile memory devices with two stacked layers of chalcogenide materials comprising the active memory device have been investigated for their potential as phase-change memories. The devices tested included GeTe/SnTe, Ge.sub.2Se.sub.3/SnTe, and Ge.sub.2Se.sub.3/SnSe stacks. All devices exhibited resistance switching behavior. The polarity of the applied voltage with respect to the SnTe or SnSe layer was critical to the memory switching properties, due to the electric field induced movement of either Sn or Te into the Ge-chalcogenide layer. One embodiment of the invention is a device comprising a stack of chalcogenide-containing layers which exhibit phase-change switching only after a reverse polarity voltage potential is applied across the stack causing ion movement into an adjacent layer and thus "activating" the device to act as a phase-change random access memory device or a reconfigurable electronics device when the applied voltage potential is returned to the normal polarity. Another embodiment of the invention is a device that is capable of exhibiting more than two data states.

Eddy Current COPV Overwrap and Liner Thickness Measurement System and Data Analysis for 40-Inch Kevlar COPVs SN002 and SN027

NASA Technical Reports Server (NTRS)

Wincheski, Russell A.

2008-01-01

As part of the health assessment of flight spare 40in diameter Kevlar composite overwrapped pressure vessels (COPVs) SN002 and SN027 an eddy current characterization of the composite and liner thickness change during pressurization was requested under WSTF-TP-1085-07.A, "Space Shuttle Orbiter Main Propulsion System P/N MC282-0082-0101 S/N 002 and Orbital Maneuvering System P/N MC282-0082-001 S/N 027 COPV Health Assessment." The through the thickness strains have been determined to be an important parameter in the analysis of the reliability and likelihood of stress rupture failure. Eddy current techniques provide a means to measure these thicknesses changes based upon the change in impedance of an eddy current sensor mounted on the exterior of the vessel. Careful probe and technique design have resulted in the capability to independently measure the liner and overwrap thickness changes to better than +/- 0.0005 in. at each sensor location. Descriptions of the inspection system and test results are discussed.

SnO2/CNT nanocomposite supercapacitors fabricated using scanning atmospheric-pressure plasma jets

NASA Astrophysics Data System (ADS)

Xu, Chang-Han; Chiu, Yi-Fan; Yeh, Po-Wei; Chen, Jian-Zhang

2016-08-01

SnO2/CNT electrodes for supercapacitors are fabricated by first screen-printing pastes containing SnO2 nanoparticles and CNTs on carbon cloth, following which nitrogen atmospheric pressure plasma jet (APPJ) sintering is performed at various APPJ scan rates. The APPJ scan rates change the time intervals for which the reactive plasma species and the heat of the nitrogen APPJs influence the designated sintering spot on the carbon cloth, resulting in APPJ-sintered SnO2/CNT nanocomposites with different properties. The water contact angle decreases with the APPJ scan rate. The improved wettability can facilitate the penetration of the electrolyte into the nanopores of the SnO2/CNT nanocomposites, thereby improving the charge storage and specific capacitance of the supercapacitors. Among the three tested APPJ scan rates, 1.5, 3, and 6 mm s-1, the SnO2/CNT supercapacitor sintered by APPJ under the lowest APPJ scan rate of 1.5 mm s-1 shows the best specific capacitance of ˜90 F g-1 as evaluated by cyclic voltammetry under a potential scan rate of 2 mV s-1. A high APPJ scan rate may result in low degree of materials activation and sintering, leading to poorer performance of SnO2/CNT supercapacitors. The results suggest the feasibility of an APPJ roll-to-roll process for the fabrication of SnO2/CNT nanocomposite supercapacitors.

Calcination Method Synthesis of SnO2/g-C3N4 Composites for a High-Performance Ethanol Gas Sensing Application

PubMed Central

Cao, Jianliang; Qin, Cong; Wang, Yan; Zhang, Bo; Gong, Yuxiao; Zhang, Huoli; Sun, Guang; Bala, Hari; Zhang, Zhanying

2017-01-01

The SnO2/g-C3N4 composites were synthesized via a facile calcination method by using SnCl4·5H2O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction (XRD), the field-emission scanning electron microscopy and transmission electron microscopy (SEM and TEM), energy dispersive spectrometry (EDS), thermal gravity and differential thermal analysis (TG-DTA), and N2-sorption. The analysis results indicated that the as-synthesized samples possess the two dimensional structure. Additionally, the SnO2 nanoparticles were highly dispersed on the surface of the g-C3N4nanosheets. The gas-sensing performance of the as-synthesized composites for different gases was tested. Moreover, the composite with 7 wt % g-C3N4 content (SnO2/g-C3N4-7) SnO2/g-C3N4-7 exhibits an admirable gas-sensing property to ethanol, which possesses a higher response and better selectivity than that of the pure SnO2-based sensor. The high surface area of the SnO2/g-C3N4 composite and the good electronic characteristics of the two dimensional graphitic carbon nitride are in favor of the elevated gas-sensing property. PMID:28468245

Comparison of Photocatalytic Performance of Different Types of Graphene in Fe3O4/SnO2 Composites

NASA Astrophysics Data System (ADS)

Paramarta, Valentinus; Taufik, Ardiansyah; Saleh, Rosari

2017-03-01

We have reported the role of annealing temperature Fe3O4/SnO2 nanocomposites as a photocatalyst for remove methylene blue (MB) dye from aqueous solution. However, how to enhanced the degradation performance of Fe3O4/SnO2 nanocomposites is important to its photocatalytic application. Therefore, in this work Fe3O4/SnO2 nanocomposites was combined with two different types of graphene materials (NGP and grahene) to improve the photocatalytic performance for remove methylene blue (MB) dye. Fe3O4/SnO2/NGP and Fe3O4/SnO2/graphene have been successfully synthesized by co-precipitation method. The influence of two types graphene on Fe3O4/SnO2 nanocomposites properties were systematically investigated by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Thermal gravimetric analysis (TGA). Degradation of methylene Blue (MB) in aqueous solution was studied in detail under photocatalytic process. Effect of catalyst dosage (0.1-0.4 g/L) and scavengers on dye degradation were carried out to check the efficiency of photocatalyst. The results indicated Fe3O4/SnO2/graphene displayed higher photocatalytic activity than other catalyst. The reusability tests have also been done to ensure the stability of the used photocatalyst.

Bouquet-Like Mn2SnO4 Nanocomposite Engineered with Graphene Sheets as an Advanced Lithium-Ion Battery Anode.

PubMed

Rehman, Wasif Ur; Xu, Youlong; Sun, Xiaofei; Ullah, Inam; Zhang, Yuan; Li, Long

2018-05-30

Volume expansion is a major challenge associated with tin oxide (SnO x ), which causes poor cyclability in lithium-ion battery anode. Bare tin dioxide (SnO 2 ), tin dioxide with graphene sheets (SnO 2 @GS), and bouquet-like nanocomposite structure (Mn 2 SnO 4 @GS) are prepared via hydrothermal method followed by annealing. The obtained composite material presents a bouquet structure containing manganese and tin oxide nanoparticle network with graphene sheets. Benefiting from this porous nanostructure, in which graphene sheets provide high electronic pathways to enhance the electronic conductivity, uniformly distributed particles offer accelerated kinetic reaction with lithium ion and reduced volume deviation in the tin dioxide (SnO 2 ) particle during charge-discharge testing. As a consequence, ternary composite Mn 2 SnO 4 @GS showed a high rate performance and outstanding cyclability of anode material for lithium-ion batteries. The electrode achieved a specific capacity of about 1070 mA h g -1 at a current density of 400 mA g -1 after 200 cycles; meanwhile, the electrode still delivered a specific capacity of about 455 mA h g -1 at a high current density of 2500 mA g -1 . Ternary Mn 2 SnO 4 @GS material could facilitate fabrication of unique structure and conductive network as advanced lithium-ion battery.

Effects of High-Temperature Treatment on the Reaction Between Sn-3%Ag-0.5%Cu Solder and Sputtered Ni-V Film on Ferrite Substrate

NASA Astrophysics Data System (ADS)

Shen, Xiaohu; Jin, Hao; Dong, Shurong; Wong, Hei; Zhou, Jian; Guo, Zhaodi; Wang, Demiao

2012-11-01

We have demonstrated a novel sputtering method for lead-free thin metal films on ferrite substrates for surface-mount inductor applications. In a surface-mounting process, the cladding of enameled wire needs to be burnt off at high temperature, which requires the devices to withstand a high-temperature reliability test at 420°C for 10 s. There are no reports that a sputtered film of thickness less than 6 μm can withstand this test. In this work, we used Ag/Ni-7 wt.%V double metal layers for the metallization. The dissolution of Ni-7 wt.%V in Sn-3%Ag-0.5%Cu lead-free solder at various temperatures was studied in detail. Scanning electron microscopy with energy-dispersive x-ray spectroscopy was used to investigate the interfacial reaction between the sputtered films and the solder. The intermetallic compounds are mainly (Cu,Ni)6Sn5 at 250°C; however, (Ni,Cu)3Sn4 becomes the predominant composition at 420°C. In addition, although outdiffusion of V atoms from the Ni-V layer was observed, its effect on the intermetallic compound (IMC) was insignificant. We further confirmed that the proposed metallization is able to pass the aforementioned high-temperature reliability test.

Accelerated fatigue durability of a high performance composite

NASA Technical Reports Server (NTRS)

Rotem, A.

1982-01-01

The fatigue behavior of multidirectional graphite-epoxy laminates was analyzed theoretically and experimentally in an effort to establish an accelerated testing methodology. Analysis of the failure mechanism in fatigue of the laminates led to the determination of the failure mode governing fracture. The nonlinear, cyclic-dependent shear modulus was used to calculate the changing stress field in the laminate during the fatigue loading. Fatigue tests were performed at three different temperatures: 25 C, 74 C, and 114 C. The prediction of the S-N curves was made based on the artificial static strength artificial static strength at a reference temperature and the fatigue functions associated with them. The prediction of an S-N curve at other temperatures was performed using shifting factors determined for the specific failure mode. For multidirectional laminates, different S-N curves at different temperatures could be predicted using these shifting factors. Different S-N curves at different temperatures occur only when the fatigue failure mode is matrix dominated. It was found that whenever the fatigue failure mode is fiber dominated, temperature, over the range investigated, had no influence on the fatigue life. These results permit the prediction of long-time, low temperature fatigue behavior from data obtained in short time, high temperature testing, for laminates governed by a matrix failure mode.

Type-Ia Supernova Rates to Redshift 2.4 from Clash: The Cluster Lensing and Supernova Survey with Hubble

NASA Technical Reports Server (NTRS)

Graur, O.; Rodney, S. A.; Maoz, D.; Riess, A. G.; Jha, S. W.; Postman, M.; Dahlen, T.; Holoien, T. W.-S.; McCully, C.; Patel, B.;

The protective effect of SnF2 containing toothpastes and solution on enamel surfaces subjected to erosion and abrasion in situ.

PubMed

Hove, L H; Stenhagen, K R; Holme, B; Tveit, A B

2014-08-01

Stannous fluoride solutions have shown promising protective effect against erosion/abrasion, but the effect of SnF2 toothpastes is uncertain. The aim of the study was to test the inhibiting effect of two SnF2 toothpastes and a SnF2 solution against erosive/abrasive wear in a single-blind, randomised in situ study, using a white light interferometer. Sixteen human molars were each divided into four specimens, mounted on mouth appliances and worn by 8 volunteers for 9 days. Specimens were brushed with toothpaste twice each day for 30 s either with fluoride-free toothpaste or toothpastes including SnF2. Toothpaste was left on the surface for 90 additional seconds. Group 1, fluoride-free toothpaste; Group 2, toothpaste A (0.4% SnF2, Solidox); Group 3, toothpaste B (0.454 % SnF2, Oral-B(®)); Group 4, brushed with fluoride-free toothpaste (30 s) and treated for 2 min with a 0.4 % SnF2 solution (1,000 ppm F). To mimic gastric reflux/vomit, specimens were etched for 2 min twice a day (0.01 M HCl). Procedures were performed extra-orally. The mean enamel wear (in μm) for the control specimens was: -29.2 ± SD 10.5; for group 2 -14.5 SD ± 9.3; for group 3 -33.3 SD ± 7.4, and for group 4 +0.4 SD ± 1.3. The specimens treated with SnF2 solution and toothpaste A showed significantly lower enamel wear than the control group. Toothpaste B gave no significant reduction in enamel wear. The SnF2 solution fully protected the enamel surface against erosive and abrasive challenges. The SnF2 toothpaste A (Solidox) showed less, but significant protection of the enamel, while no statistically significant protection was demonstrated by SnF2 toothpaste B (Oral-B(®) Pro-Expert).

Type-Ia supernova rates to redshift 2.4 from clash: The cluster lensing and supernova survey with Hubble

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

Graur, O.; Rodney, S. A.; Riess, A. G.

2014-03-01

We present the supernova (SN) sample and Type-Ia SN (SN Ia) rates from the Cluster Lensing And Supernova survey with Hubble (CLASH). Using the Advanced Camera for Surveys and the Wide Field Camera 3 on the Hubble Space Telescope (HST), we have imaged 25 galaxy-cluster fields and parallel fields of non-cluster galaxies. We report a sample of 27 SNe discovered in the parallel fields. Of these SNe, ∼13 are classified as SN Ia candidates, including four SN Ia candidates at redshifts z > 1.2. We measure volumetric SN Ia rates to redshift 1.8 and add the first upper limit onmore » the SN Ia rate in the range 1.8 < z < 2.4. The results are consistent with the rates measured by the HST/GOODS and Subaru Deep Field SN surveys. We model these results together with previous measurements at z < 1 from the literature. The best-fitting SN Ia delay-time distribution (DTD; the distribution of times that elapse between a short burst of star formation and subsequent SN Ia explosions) is a power law with an index of −1.00{sub −0.06(0.10)}{sup +0.06(0.09)} (statistical){sub −0.08}{sup +0.12} (systematic), where the statistical uncertainty is a result of the 68% and 95% (in parentheses) statistical uncertainties reported for the various SN Ia rates (from this work and from the literature), and the systematic uncertainty reflects the range of possible cosmic star-formation histories. We also test DTD models produced by an assortment of published binary population synthesis (BPS) simulations. The shapes of all BPS double-degenerate DTDs are consistent with the volumetric SN Ia measurements, when the DTD models are scaled up by factors of 3-9. In contrast, all BPS single-degenerate DTDs are ruled out by the measurements at >99% significance level.« less

Three gravitationally lensed supernovae behind clash galaxy clusters

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

Patel, Brandon; McCully, Curtis; Jha, Saurabh W.

2014-05-01

We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z = 0.345), and A383 (z = 0.187), respectively. Each SN was detected in Hubble Space Telescope optical and infrared images. Based on photometric classification, we find that SNe CLO12Car and CLN12Did are likely to be Type Ia supernovae (SNe Ia), while the classification of SN CLA11Tib is inconclusive.more » Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, we infer that SN CLO12Car was ∼1.0 ± 0.2 mag brighter than field SNe Ia at a similar redshift and ascribe this to gravitational lens magnification. Similarly, SN CLN12Did is ∼0.2 ± 0.2 mag brighter than field SNe Ia. We derive independent estimates of the predicted magnification from CLASH strong+weak-lensing maps of the clusters (in magnitude units, 2.5 log{sub 10}μ): 0.83 ± 0.16 mag for SN CLO12Car, 0.28 ± 0.08 mag for SN CLN12Did, and 0.43 ± 0.11 mag for SN CLA11Tib. The two SNe Ia provide a new test of the cluster lens model predictions: we find that the magnifications based on the SN Ia brightness and those predicted by the lens maps are consistent. Our results herald the promise of future observations of samples of cluster-lensed SNe Ia (from the ground or space) to help illuminate the dark-matter distribution in clusters of galaxies, through the direct determination of absolute magnifications.« less

Three Gravitationally Lensed Supernovae Behind Clash Galaxy Clusters

NASA Technical Reports Server (NTRS)

Patel, Brandon; McCully, Curtis; Jha, Saurbh W.; Rodney, Steven A.; Jones, David O.; Graur, Or; Merten, Julian; Zitrin, Adi; Riess, Adam G.; Matheson, Thomas;

Pitfalls in efficacy testing – how important is the validation of neutralization of chlorhexidine digluconate?

PubMed Central

Reichel, Mirja; Heisig, Peter; Kampf, Günter

2008-01-01

Background Effective neutralization of active agents is essential to obtain valid efficacy results, especially when non-volatile active agents like chlorhexidine digluconate (CHG) are tested. The aim of this study was to determine an effective and non-toxic neutralizing mixture for a propan-1-ol solution containing 2% CHG. Methods Experiments were carried out according to ASTM E 1054-02. The neutralization capacity was tested separately with five challenge microorganisms in suspension, and with a rayon swab carrier. Either 0.5 mL of the antiseptic solution (suspension test) or a saturated swab with the antiseptic solution (carrier test) was added to tryptic soy broth containing neutralizing agents. After the samples were mixed, aliquots were spread immediately and after 3 h of storage at 2 – 8°C onto tryptic soy agar containing a neutralizing mixture. Results The neutralizer was, however, not consistently effective in the suspension test. Immediate spread yielded a valid neutralization with Staphylococcus aureus, Staphylococcus epidermidis and Corynebacterium jeikeium but not with Micrococcus luteus (p < 0.001) and Candida albicans (p < 0.001). A 3-h storage period of the neutralized active agents in suspension resulted in significant carry-over activity of CHG in addition against Staphylococcus epidermidis (p < 0.001) and Corynebacterium jeikeium (p = 0.044). In the carrier test, the neutralizing mixture was found to be effective and non toxic to all challenge microorganisms when spread immediately. However, after 3 h storage of the neutralized active agents significant carry-over activity of CHG against Micrococcus luteus (p = 0.004; Tukey HSD) was observed. Conclusion Without effective neutralization in the sampling fluid, non-volatile active ingredients will continue to reduce the number of surviving microorganisms after antiseptic treatment even if the sampling fluid is kept cold straight after testing. This can result in false-positive antiseptic efficacy data. Attention should be paid during the neutralization validation process to the amount of antiseptic solution, the storage time and to the choice of appropriate and sensitive microorganisms. PMID:19046465

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: Initial Comprehensive Performance Test Report, P/N 1331200-2-IT, S/N 105/A2

NASA Technical Reports Server (NTRS)

Platt, R.

1999-01-01

This is the Performance Verification Report, Initial Comprehensive Performance Test Report, P/N 1331200-2-IT, S/N 105/A2, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The specification establishes the requirements for the Comprehensive Performance Test (CPT) and Limited Performance Test (LPT) of the Advanced Microwave Sounding, Unit-A2 (AMSU-A2), referred to herein as the unit. The unit is defined on Drawing 1331200. 1.2 Test procedure sequence. The sequence in which the several phases of this test procedure shall take place is shown in Figure 1, but the sequence can be in any order.

A hollow cathode neutralizer for a 30-cm diameter bombardment thruster

NASA Technical Reports Server (NTRS)

Bechtel, R. T.

1973-01-01

Recent improvements in overall thrustor performance have imposed new constraints on neutralizer performance. The use of compensated grid extraction system requires a re-evaluation of neutralizer position. In addition a suitable control logic for the neutralizer has proven difficult. A series of tests were conducted to determine what effect neutralizer cathode geometry has on performance. The parameters investigated included orifice diameter and length, and cathode diameter. Similar tests investigated open and enclosed keeper geometries. Neutralizer position tests with compensated grids suggest positions approximately 10 cm from the accelerator and radially out of the beam envelope should result in satisfactory performance and long life. Finally operation at keeper currents of 1.5 amp has resulted in lower total neutralizer power, the elimination of tip heater power, and suitable closed loop control of the neutralizer vaporizer.

The effects of glycogen synthase kinase-3beta in serotonin neurons.

PubMed

Zhou, Wenjun; Chen, Ligong; Paul, Jodi; Yang, Sufen; Li, Fuzeng; Sampson, Karen; Woodgett, Jim R; Beaulieu, Jean Martin; Gamble, Karen L; Li, Xiaohua

2012-01-01

Glycogen synthase kinase-3 (GSK3) is a constitutively active protein kinase in brain. Increasing evidence has shown that GSK3 acts as a modulator in the serotonin neurotransmission system, including direct interaction with serotonin 1B (5-HT1B) receptors in a highly selective manner and prominent modulating effect on 5-HT1B receptor activity. In this study, we utilized the serotonin neuron-selective GSK3β knockout (snGSK3β-KO) mice to test if GSK3β in serotonin neurons selectively modulates 5-HT1B autoreceptor activity and function. The snGSK3β-KO mice were generated by crossbreeding GSK3β-floxed mice and ePet1-Cre mice. These mice had normal growth and physiological characteristics, similar numbers of tryptophan hydroxylase-2 (TpH2)-expressing serotonin neurons, and the same brain serotonin content as in littermate wild type mice. However, the expression of GSK3β in snGSK3β-KO mice was diminished in TpH2-expressing serotonin neurons. Compared to littermate wild type mice, snGSK3β-KO mice had a reduced response to the 5-HT1B receptor agonist anpirtoline in the regulation of serotonergic neuron firing, cAMP production, and serotonin release, whereas these animals displayed a normal response to the 5-HT1A receptor agonist 8-OH-DPAT. The effect of anpirtoline on the horizontal, center, and vertical activities in the open field test was differentially affected by GSK3β depletion in serotonin neurons, wherein vertical activity, but not horizontal activity, was significantly altered in snGSK3β-KO mice. In addition, there was an enhanced anti-immobility response to anpirtoline in the tail suspension test in snGSK3β-KO mice. Therefore, results of this study demonstrated a serotonin neuron-targeting function of GSK3β by regulating 5-HT1B autoreceptors, which impacts serotonergic neuron firing, serotonin release, and serotonin-regulated behaviors.

Deja Vu All Over Again: The Reappearance of Supernova Refsdal

NASA Astrophysics Data System (ADS)

Kelly, P. L.; Rodney, S. A.; Treu, T.; Strolger, L.-G.; Foley, R. J.; Jha, S. W.; Selsing, J.; Brammer, G.; Bradač, M.; Cenko, S. B.; Graur, O.; Filippenko, A. V.; Hjorth, J.; McCully, C.; Molino, A.; Nonino, M.; Riess, A. G.; Schmidt, K. B.; Tucker, B.; von der Linden, A.; Weiner, B. J.; Zitrin, A.

2016-03-01

In Hubble Space Telescope (HST) imaging taken on 2014 November 10, four images of supernova (SN) “Refsdal” (redshift z = 1.49) appeared in an Einstein-cross-like configuration (images S1-S4) around an early-type galaxy in the cluster MACS J1149.5+2223 (z = 0.54). Almost all lens models of the cluster have predicted that the SN should reappear within a year in a second host-galaxy image created by the cluster’s potential. In HST observations taken on 2015 December 11, we find a new source at the predicted position of the new image of SN Refsdal approximately 8\\prime\\prime from the previous images S1-S4. This marks the first time the appearance of a SN at a particular time and location in the sky was successfully predicted in advance! We use these data and the light curve from the first four observed images of SN Refsdal to place constraints on the relative time delay and magnification of the new image (SX) compared to images S1-S4. This enables us, for the first time, to test “blind” lens model predictions of both magnifications and time delays for a lensed SN. We find that the timing and brightness of the new image are consistent with the blind predictions of a fraction of the models. The reappearance illustrates the discriminatory power of this blind test and its utility to uncover sources of systematic uncertainty. From planned HST photometry, we expect to reach a precision of 1%-2% on the time delay between S1-S4 and SX.

Deja Vu All Over Again: The Reappearance of Supernova Refsdal

NASA Technical Reports Server (NTRS)

Kelly, P.L.; Rodney, S.A.; Treu, T.; Strolger, L.-G.; Foley, R.J.; Jha, S.W.; Selsing, J.; Brammer, G.; Bradac, M.; Cenko, S. B.

2016-01-01

In Hubble Space Telescope (HST) imaging taken on 2014 November 10, four images of supernova (SN) Refsdal(redshift z1.49) appeared in an Einstein-cross-like configuration (images S1S4) around an early-type galaxy in the cluster MACS J1149.5+2223 (z0.54). Almost all lens models of the cluster have predicted that the SN should reappear within a year in a second host-galaxy image created by the clusters potential. In HST observations taken on 2015 December 11, we find a new source at the predicted position of the new image of SN Refsdal approximately 8 from the previous images S1S4. This marks the first time the appearance of a SN at a particular time and location in the sky was successfully predicted in advance! We use these data and the light curve from the first four observed images of SN Refsdal to place constraints on the relative time delay and magnification of the new image (SX) compared to images S1S4. This enables us, for the first time, to test blind lens model predictions of both magnifications and time delays for a lensed SN. We find that the timing and brightness of the new image are consistent with the blind predictions of a fraction of the models. The reappearance illustrates the discriminatory power of this blind test and its utility to uncover sources of systematic uncertainty. From planned HST photometry, we expect to reach a precision of 12 on the time delay between S1S4 and SX.

Summary of Test Results of MQXFS1 - The First Short Model 150 mm Aperture $$Nb_3Sn$$ Quadrupole for the High-Luminosity

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

Stoynev, S.; et al.

The development ofmore » $$Nb_3Sn$$ quadrupole magnets for the High-Luminosity LHC upgrade is a joint venture between the US LHC Accelerator Research Program (LARP)* and CERN with the goal of fabricating large aperture quadrupoles for the LHC in-teraction regions (IR). The inner triplet (low-β) NbTi quadrupoles in the IR will be replaced by the stronger Nb3Sn magnets boosting the LHC program of having 10-fold increase in integrated luminos-ity after the foreseen upgrades. Previously LARP conducted suc-cessful tests of short and long models with up to 120 mm aperture. The first short 150 mm aperture quadrupole model MQXFS1 was assembled with coils fabricated by both CERN and LARP. The magnet demonstrated strong performance at the Fermilab’s verti-cal magnet test facility reaching the LHC operating limits. This paper reports the latest results from MQXFS1 tests with changed pre-stress levels. The overall magnet performance, including quench training and memory, ramp rate and temperature depend-ence, is also summarized.« less

Neutralization efficiency of alcohol based products used for rapid hand disinfection

PubMed

Chojecka, Agnieszka; Tarka, Patryk; Kierzkowska, Anna; Nitsch-Osuch, Aneta; Kanecki, Krzysztof

Alcohols are the most commonly used active substances in preparations for quick hand disinfection. They should be bactericidal in very short contact time. PN-EN 13727 + A2: 2015-12 standard, for testing hygienic and surgical handrub disinfection preparations, provides mandatory test conditions of disinfectants in contact times with the range of 30 s to 60 s (hygienic handrub disinfection) and 60 s to 5 min (surgical handrub disinfection). A short contact times for hand hygiene products require a short time of neutralization process. For contact times less than or equal to 10 minutes, the estimated neutralization time is 10 s ± 1 s. Neutralization is a process that abolishes the action of disinfectants. Correct application of this process allows for proper use of disinfectants in practice and its biocidal effect. Objectives. Verification of the effectiveness of 10-second neutralization time of alcohol based preparations for hygienic handrub disinfection Neutralization of two products with different ethanol content (89% and 70%) for hygienic handrub disinfection according to PN-EN 13727 + A2: 2015-12 was investigated. The effectiveness of the neutralizer was assessed by determining toxicity of neutralizer, activity of residual effects of the tested products and their derivatives produced during neutralization (10 s) for test organisms (Staphylococcus aureus ATCC 6538; Pseudomonas aeruginosa ATCC 15442; Enterococcus hirae ATCC 10541; Escherichia coli K12 NCTC 10538) The 10-second neutralization time was sufficient to eliminate the residual activity of products for hygienic handrub disinfection with differentiated ethanol concentration. The neutralizer used did not show toxicity to bacteria and did not produce toxic products with tested preparations after neutralization Conclusions. The use of 10-second neutralization time allows in a precise way designate the contact times for hygienic handrub disinfection products

Structure and Mechanical Properties of As-Cast Ti-5Sn-xMo Alloys.

PubMed

Yu, Hsing-Ning; Hsu, Hsueh-Chuan; Wu, Shih-Ching; Hsu, Shih-Kuang; Ho, Wen-Fu

2017-04-27

Ti-5Sn- x Mo ( x = 0, 1, 3, 5, 7.5, 10, 12.5, 15, 17.5, and 20 wt %) alloys were designed and prepared for application as implant materials with superior mechanical properties. The results demonstrated that the crystal structure and mechanical properties of Ti-5Sn- x Mo alloys are highly affected by their Mo content. The as-cast microstructures of Ti-5Sn- x Mo alloys transformed in the sequence of phases α' → α″ → β, and the morphologies of the alloys changed from a lath structure to an equiaxed structure as the Mo content increased. The α″-phase Ti-5Sn-7.5Mo (80 GPa) and β-phase Ti-5Sn-10Mo (85 GPa) exhibited relatively low elastic moduli and had excellent elastic recovery angles of 27.4° and 37.8°, respectively. Furthermore, they exhibited high ductility and moderate strength, as evaluated using the three-point bending test. Search for a more suitable implant material by this study, Ti-5Sn- x Mo alloys with 7.5 and 10 wt % Mo appear to be promising candidates because they demonstrate the optimal combined properties of microhardness, ductility, elastic modulus, and elastic recovery capability.

Electrochemical corrosion and bioactivity of Ti-Nb-Sn-hydroxyapatite composites fabricated by pulse current activated sintering.

PubMed

Xiaopeng, Wang; Fantao, Kong; Biqing, Han; Yuyong, Chen

2017-11-01

Ti-Nb-Sn-hydroxyapatite (HA) composites were prepared by mechanical alloying for different times (unmilled, 4, 8 and 12h), followed by pulse current activated sintering. The effects of the milling time on the electrochemical corrosion resistance and bioactivity of the sintered Ti-35Nb-2.5Sn-15HA composites were investigated. Potentiodynamic polarization test results indicated that the sintered Ti-35Nb-2.5Sn-15HA composites exhibited higher corrosion resistance with increasing milling time. The corrosion potential and current of the Ti-35Nb-2.5Sn-15HA composite sintered by 12h milled powders were - 0.261V and 0.18μA/cm 2 , respectively, and this sintered composite showed a stable and wide passivation region. The hemolysis rate of the sintered Ti-35Nb-2.5Sn-15HA composites reduced with increasing milling time and the lowest hemolytic rate of the composites was 0.87%. In addition, the in vitro cell culture results indicated that the composite sintered by 12h milled powders had good biocompatibility. These results indicate the significant potential of Ti-35Nb-2.5Sn/xHA composites for biomedical implant applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Strain Rate on Joint Strength and Failure Mode of Lead-Free Solder Joints

NASA Astrophysics Data System (ADS)

Lin, Jian; Lei, Yongping; Fu, Hanguang; Guo, Fu

2018-03-01

In surface mount technology, the Sn-3.0Ag-0.5Cu solder joint has a shorter impact lifetime than a traditional lead-tin solder joint. In order to improve the impact property of SnAgCu lead-free solder joints and identify the effect of silver content on tensile strength and impact property, impact experiments were conducted at various strain rates on three selected SnAgCu based solder joints. It was found that joint failure mainly occurred in the solder material with large plastic deformation under low strain rate, while joint failure occurred at the brittle intermetallic compound layer without any plastic deformation at a high strain rate. Joint strength increased with the silver content in SnAgCu alloys in static tensile tests, while the impact property of the solder joint decreased with increasing silver content. When the strain rate was low, plastic deformation occurred with failure and the tensile strength of the Sn-3.0Ag-0.5Cu solder joint was higher than that of Sn-0.3Ag-0.7Cu; when the strain rate was high, joint failure mainly occurred at the brittle interface layer and the Sn-0.3Ag-0.7Cu solder joint had a better impact resistance with a thinner intermetallic compound layer.

Molecular Characterization of the Elaeis guineensis Medium-Chain Fatty Acid Diacylglycerol Acyltransferase DGAT1-1 by Heterologous Expression in Yarrowia lipolytica.

PubMed

Aymé, Laure; Jolivet, Pascale; Nicaud, Jean-Marc; Chardot, Thierry

2015-01-01

Diacylglycerol acyltransferases (DGAT) are involved in the acylation of sn-1,2-diacylglycerol. Palm kernel oil, extracted from Elaeis guineensis (oil palm) seeds, has a high content of medium-chain fatty acids mainly lauric acid (C12:0). A putative E. guineensis diacylglycerol acyltransferase gene (EgDGAT1-1) is expressed at the onset of lauric acid accumulation in the seed endosperm suggesting that it is a determinant of medium-chain triacylglycerol storage. To test this hypothesis, we thoroughly characterized EgDGAT1-1 activity through functional complementation of a Yarrowia lipolytica mutant strain devoid of neutral lipids. EgDGAT1-1 expression is sufficient to restore triacylglycerol accumulation in neosynthesized lipid droplets. A comparative functional study with Arabidopsis thaliana DGAT1 highlighted contrasting substrate specificities when the recombinant yeast was cultured in lauric acid supplemented medium. The EgDGAT1-1 expressing strain preferentially accumulated medium-chain triacylglycerols whereas AtDGAT1 expression induced long-chain triacylglycerol storage in Y. lipolytica. EgDGAT1-1 localized to the endoplasmic reticulum where TAG biosynthesis takes place. Reestablishing neutral lipid accumulation in the Y. lipolytica mutant strain did not induce major reorganization of the yeast microsomal proteome. Overall, our findings demonstrate that EgDGAT1-1 is an endoplasmic reticulum DGAT with preference for medium-chain fatty acid substrates, in line with its physiological role in palm kernel. The characterized EgDGAT1-1 could be used to promote medium-chain triacylglycerol accumulation in microbial-produced oil for industrial chemicals and cosmetics.

Molecular Characterization of the Elaeis guineensis Medium-Chain Fatty Acid Diacylglycerol Acyltransferase DGAT1-1 by Heterologous Expression in Yarrowia lipolytica

PubMed Central

Aymé, Laure; Jolivet, Pascale; Nicaud, Jean-Marc; Chardot, Thierry

2015-01-01

Diacylglycerol acyltransferases (DGAT) are involved in the acylation of sn-1,2-diacylglycerol. Palm kernel oil, extracted from Elaeis guineensis (oil palm) seeds, has a high content of medium-chain fatty acids mainly lauric acid (C12:0). A putative E. guineensis diacylglycerol acyltransferase gene (EgDGAT1-1) is expressed at the onset of lauric acid accumulation in the seed endosperm suggesting that it is a determinant of medium-chain triacylglycerol storage. To test this hypothesis, we thoroughly characterized EgDGAT1-1 activity through functional complementation of a Yarrowia lipolytica mutant strain devoid of neutral lipids. EgDGAT1-1 expression is sufficient to restore triacylglycerol accumulation in neosynthesized lipid droplets. A comparative functional study with Arabidopsis thaliana DGAT1 highlighted contrasting substrate specificities when the recombinant yeast was cultured in lauric acid supplemented medium. The EgDGAT1-1 expressing strain preferentially accumulated medium-chain triacylglycerols whereas AtDGAT1 expression induced long-chain triacylglycerol storage in Y. lipolytica. EgDGAT1-1 localized to the endoplasmic reticulum where TAG biosynthesis takes place. Reestablishing neutral lipid accumulation in the Y. lipolytica mutant strain did not induce major reorganization of the yeast microsomal proteome. Overall, our findings demonstrate that EgDGAT1-1 is an endoplasmic reticulum DGAT with preference for medium-chain fatty acid substrates, in line with its physiological role in palm kernel. The characterized EgDGAT1-1 could be used to promote medium-chain triacylglycerol accumulation in microbial-produced oil for industrial chemicals and cosmetics. PMID:26581109

Neutrality between Government and Religion.

ERIC Educational Resources Information Center

Mawdsley, Ralph D.

1996-01-01

The overall guiding principle of neutrality between government and religion masks a tension that exists between free exercise of religion and establishment of religion. Reviews the development and current status of "Lemon" as a test for neutrality; proposes a new test for neutrality, evenhandedness, that is common to both the Free…

Field Quality Study of a 1-m-Long Single-Aperture 11-T Nb$$_3$$Sn Dipole Model for LHC Upgrades

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

Chlachidze, G.; DiMarco, J.; Andreev, N.

2014-01-01

FNAL and CERN are carrying out a joint R&D program with the goal of building a 5.5-m-long twin-aperture 11-T Nb_3Sn dipole prototype that is suitable for installation in the LHC. An important part of the program is the development and test of a series of short single-aperture and twin-aperture dipole models with a nominal field of 11 T at the LHC operation current of 11.85 kA and 20% margin. This paper presents the results of magnetic measurements of a 1-m-long single-aperture Nb_3Sn dipole model fabricated and tested recently at FNAL, including geometrical field harmonics and effects of coil magnetization andmore » iron yoke saturation.« less

Optimization of dual-energy xenon-computed tomography for quantitative assessment of regional pulmonary ventilation.

PubMed

Fuld, Matthew K; Halaweish, Ahmed F; Newell, John D; Krauss, Bernhard; Hoffman, Eric A

2013-09-01

Dual-energy x-ray computed tomography (DECT) offers visualization of the airways and quantitation of regional pulmonary ventilation using a single breath of inhaled xenon gas. In this study, we sought to optimize scanning protocols for DECT xenon gas ventilation imaging of the airways and lung parenchyma and to characterize the quantitative nature of the developed protocols through a series of test-object and animal studies. The Institutional Animal Care and Use Committee approved all animal studies reported here. A range of xenon/oxygen gas mixtures (0%, 20%, 25%, 33%, 50%, 66%, 100%; balance oxygen) were scanned in syringes and balloon test-objects to optimize the delivered gas mixture for assessment of regional ventilation while allowing for the development of improved 3-material decomposition calibration parameters. In addition, to alleviate gravitational effects on xenon gas distribution, we replaced a portion of the oxygen in the xenon/oxygen gas mixture with helium and compared gas distributions in a rapid-prototyped human central-airway test-object. Additional syringe tests were performed to determine if the introduction of helium had any effect on xenon quantitation. Xenon gas mixtures were delivered to anesthetized swine to assess airway and lung parenchymal opacification while evaluating various DECT scan acquisition settings. Attenuation curves for xenon were obtained from the syringe test-objects and were used to develop improved 3-material decomposition parameters (Hounsfield unit enhancement per percentage xenon: within the chest phantom, 2.25 at 80 kVp, 1.7 at 100 kVp, and 0.76 at 140 kVp with tin filtration; in open air, 2.5 at 80 kVp, 1.95 at 100 kVp, and 0.81 at 140 kVp with tin filtration). The addition of helium improved the distribution of xenon gas to the gravitationally nondependent portion of the airway tree test-object, while not affecting the quantitation of xenon in the 3-material decomposition DECT. The mixture 40% Xe/40% He/20% O2 provided good signal-to-noise ratio (SNR), greater than the Rose criterion (SNR > 5), while avoiding gravitational effects of similar concentrations of xenon in a 60% O2 mixture. Compared with 100/140 Sn kVp, 80/140 Sn kVp (Sn = tin filtered) provided improved SNR in a swine with an equivalent thoracic transverse density to a human subject with a body mass index of 33 kg/m. Airways were brighter in the 80/140 Sn kVp scan (80/140 Sn, 31.6%; 100/140 Sn, 25.1%) with considerably lower noise (80/140 Sn, coefficient of variation of 0.140; 100/140 Sn, coefficient of variation of 0.216). To provide a truly quantitative measure of regional lung function with xenon-DECT, the basic protocols and parameter calibrations need to be better understood and quantified. It is critically important to understand the fundamentals of new techniques to allow for proper implementation and interpretation of their results before widespread usage. With the use of an in-house derived xenon calibration curve for 3-material decomposition rather than the scanner supplied calibration and a xenon/helium/oxygen mixture, we demonstrate highly accurate quantitation of xenon gas volumes and avoid gravitational effects on gas distribution. This study provides a foundation for other researchers to use and test these methods with the goal of clinical translation.

LOSS Revisited. II. The Relative Rates of Different Types of Supernovae Vary between Low- and High-mass Galaxies

NASA Astrophysics Data System (ADS)

Graur, Or; Bianco, Federica B.; Modjaz, Maryam; Shivvers, Isaac; Filippenko, Alexei V.; Li, Weidong; Smith, Nathan

2017-03-01

In Paper I of this series, we showed that the ratio between stripped-envelope (SE) supernova (SN) and Type II SN rates reveals a significant SE SN deficiency in galaxies with stellar masses ≲ {10}10 {M}⊙ . Here, we test this result by splitting the volume-limited subsample of the Lick Observatory Supernova Search (LOSS) SN sample into low- and high-mass galaxies and comparing the relative rates of various SN types found in them. The LOSS volume-limited sample contains 180 SNe and SN impostors and is complete for SNe Ia out to 80 Mpc and core-collapse SNe out to 60 Mpc. All of these transients were recently reclassified by us in Shivvers et al. We find that the relative rates of some types of SNe differ between low- and high-mass galaxies: SNe Ib and Ic are underrepresented by a factor of ˜3 in low-mass galaxies. These galaxies also contain the only examples of SN 1987A-like SNe in the sample and host about nine times as many SN impostors. Normal SNe Ia seem to be ˜30% more common in low-mass galaxies, making these galaxies better sources for homogeneous SN Ia cosmology samples. The relative rates of SNe IIb are consistent in both low- and high-mass galaxies. The same is true for broad-line SNe Ic, although our sample includes only two such objects. The results presented here are in tension with a similar analysis from the Palomar Transient Factory, especially as regards SNe IIb.

Comparative sensitivity of juvenile and adult Potamopyrgus antipodarum (Mollusca: Hydrobiidae) under chronic exposure to cadmium and tributyltin.

PubMed

Ruppert, Katharina; Geiß, Cornelia; Ostermann, Sina; Theis, Christina; Oehlmann, Jörg

2016-07-28

To investigate a potential extension of a partial life cycle test protocol to a full life cycle test design, a comparative sensitivity analysis with juvenile and adult Potamopyrgus antipodarum was performed. Neonates and adult snails were exposed to the metal cadmium (Cd) and the endocrine disruptor tributyltin (TBT) at nominal concentrations ranging from 1.56 to 50 μg Cd/L and from 25 to 1,000 ng TBT-Sn/L. The experiments were performed over 28 days at 16°C in a semi-static test design. Mortality was assessed for both life stages. Juvenile snails' specific growth rate and reproduction of adults were investigated as main endpoints. We determined effects on snails' survival, juvenile growth and embryo numbers in the brood pouch of adult snails under exposure to both chemicals. Juvenile control mortality was between 25% and 30% and significantly higher than in the control groups with adult snails. A higher sensitivity of juvenile snails compared to adults was observed for the endpoint mortality. Calculated LC50 in Cd exposed snails was 38.2 μg/L for adults and 15.0 μg/L for juvenile snails. Significant effects on mortality in TBT exposed adult snails occurred at the highest test concentration only with a LC50 of 535 ng Sn/L. Juvenile survival was significantly affected at 50.8 ng Sn/L and higher concentrations. Effect concentrations for the main endpoints reproduction and juvenile growth show comparable sensitivities. For Cd exposed groups, EC50 values were 11.3 μg/L for the endpoint reproduction in adult snails and 3.82 μg/L for juvenile growth with overlapping confidence intervals. TBT also significantly affected juvenile snails' growth (EC50: 178 ng Sn /L). EC50 for embryo numbers was 125 ng TBT-Sn/L. Results indicate the manageability of a FLC test starting with newly hatched snails. Precautions have to be taken to guarantee a sufficient number of surviving snails until adulthood so that reproduction can be assessed. For final decision for the practicability of a FLC, further tests are needed.

Larp Nb3Sn Quadrupole Magnets for the Lhc Luminosity Upgrade

NASA Astrophysics Data System (ADS)

Ferracin, P.

2010-04-01

The US LHC Accelerator Research Program (LARP) is a collaboration between four US laboratories (BNL, FNAL, LBNL, and SLAC) aimed at contributing to the commissioning and operation of the LHC and conducting R&D on its luminosity upgrade. Within LARP, the Magnet Program's main goal is to demonstrate that Nb3Sn superconducting magnets are a viable option for a future upgrade of the LHC Interaction Regions. Over the past four years, LARP has successfully fabricated and tested several R&D magnets: 1) the subscale quadrupole magnet SQ, to perform technology studies with 300 mm long racetrack coils, 2) the technology quadrupole TQ, to investigate support structure behavior with 1 m long cos 2θ coils, and 3) the long racetrack magnet LR, to test 3.6 m long racetrack coils. The next milestone consists in the fabrication and test of the 3.7 m long quadrupole magnet LQ, with the goal of demonstrating that Nb3Sn technology is mature for use in high energy accelerators. After an overview of design features and test result of the LARP magnets fabricated so far, this paper focuses on the status of the fabrication of LQ: we describe the production of the 3.4 m long cos 2θ coils, and the of the qualification support structure. Finally, the status of the development of the next 1 m long model HQ, conceived to explore stress and field limits of Nb3Sn superconducting, magnets, is presented.

Illuminating a Dark Lens : A Type Ia Supernova Magnified by the Frontier Fields Galaxy Cluster Abell 2744

NASA Astrophysics Data System (ADS)

Rodney, Steven A.; Patel, Brandon; Scolnic, Daniel; Foley, Ryan J.; Molino, Alberto; Brammer, Gabriel; Jauzac, Mathilde; Bradač, Maruša; Broadhurst, Tom; Coe, Dan; Diego, Jose M.; Graur, Or; Hjorth, Jens; Hoag, Austin; Jha, Saurabh W.; Johnson, Traci L.; Kelly, Patrick; Lam, Daniel; McCully, Curtis; Medezinski, Elinor; Meneghetti, Massimo; Merten, Julian; Richard, Johan; Riess, Adam; Sharon, Keren; Strolger, Louis-Gregory; Treu, Tommaso; Wang, Xin; Williams, Liliya L. R.; Zitrin, Adi

2015-09-01

SN HFF14Tom is a Type Ia SN discovered at z=1.3457+/- 0.0001 behind the galaxy cluster Abell 2744 (z = 0.308). In a cosmology-independent analysis, we find that HFF14Tom is 0.77 ± 0.15 mag brighter than unlensed Type Ia SNe at similar redshift, implying a lensing magnification of {μ }{obs}=2.03+/- 0.29. This observed magnification provides a rare opportunity for a direct empirical test of galaxy cluster lens models. Here we test 17 lens models, 13 of which were generated before the SN magnification was known, qualifying as pure “blind tests.” The models are collectively fairly accurate: 8 of the models deliver median magnifications that are consistent with the measured μ to within 1σ. However, there is a subtle systematic bias: the significant disagreements all involve models overpredicting the magnification. We evaluate possible causes for this mild bias, and find no single physical or methodological explanation to account for it. We do find that model accuracy can be improved to some extent with stringent quality cuts on multiply imaged systems, such as requiring that a large fraction have spectroscopic redshifts. In addition to testing model accuracies as we have done here, Type Ia SN magnifications could also be used as inputs for future lens models of Abell 2744 and other clusters, providing valuable constraints in regions where traditional strong- and weak-lensing information is unavailable.

Mechanical Strength and Failure Characterization of Sn-Ag-Cu Intermetallic Compound Joints at the Microscale

NASA Astrophysics Data System (ADS)

Ladani, Leila; Razmi, Jafar

2012-03-01

Continuous miniaturization of microelectronic devices has led the industry to develop interconnects on the order of a few microns for advanced superhigh-density and three-dimensional integrated circuits (3D ICs). At this scale, interconnects that conventionally consist of solder material will completely transform to intermetallic compounds (IMCs) such as Cu6Sn5. IMCs are brittle, unlike conventional solder materials that are ductile in nature; therefore, IMCs do not experience large amounts of plasticity or creep before failure. IMCs have not been fully characterized, and their mechanical and thermomechanical reliability is questioned. This study presents experimental efforts to characterize such material. Sn-based microbonds are fabricated in a controlled environment to assure complete transformation of the bonds to Cu6Sn5 IMC. Microstructural analysis including scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) is utilized to determine the IMC material composition and degree of copper diffusion into the bond area. Specimens are fabricated with different bond thicknesses and in different configurations for various tests. Normal strength of the bonds is measured utilizing double cantilever beam and peeling tests. Shear tests are conducted to quantify the shear strength of the material. Four-point bending tests are conducted to measure the fracture toughness and critical energy release rate. Bonds are fabricated in different sizes, and the size effect is investigated. The shear strength, normal strength, critical energy release rate, and effect of bond size on bond strength are reported.

Calculation of the visible-UV absorption spectra of hydrogen sulfide, bisulfide, polysulfides, and As and Sb sulfides, in aqueous solution

PubMed Central

Tossell, JA

2003-01-01

Recently we showed that visible-UV spectra in aqueous solution can be accurately calculated for arsenic (III) bisulfides, such as As(SH)3, As(SH)2S- and their oligomers. The calculated lowest energy transitions for these species were diagnostic of their protonation and oligomerization state. We here extend these studies to As and Sb oxidation state III and v sulfides and to polysulfides Sn2-, n = 2–6, the bisulfide anion, SH-, hydrogen sulfide, H2S and the sulfanes, SnH2, n = 2–5. Many of these calculations are more difficult than those performed for the As(iii) bisulfides, since the As and Sb(v) species are more acidic and therefore exist as highly charged anions in neutral and basic solutions. In general, small and/or highly charged anions are more difficult to describe computationally than larger, monovalent anions or neutral molecules. We have used both Hartree-Fock based (CI Singles and Time-Dependent HF) and density functional based (TD B3LYP) techniques for the calculations of absorption energy and intensity and have used both explicit water molecules and a polarizable continuum to describe the effects of hydration. We correctly reproduce the general trends observed experimentally, with absorption energies increasing from polysulfides to As, Sb sulfides to SH- to H2S. As and Sb(v) species, both monomers and dimers, also absorb at characteristically higher energies than do the analogous As and Sb(III)species. There is also a small reduction in absorption energy from monomeric to dimeric species, for both As and Sb III and v. The polysufides, on the other hand, show no simple systematic changes in UV spectra with chain length, n, or with protonation state. Our results indicate that for the As and Sb sulfides, the oxidation state, degree of protonation and degree of oligomerization can all be determined from the visible-UV absorption spectrum. We have also calculated the aqueous phase energetics for the reaction of S8 with SH- to produce the polysulfides, SnH-, n = 2–6. Our results are in excellent agreement with available experimental data, and support the existence of a S6 species.

Test results of a Nb 3Al/Nb 3Sn subscale magnet for accelerator application

DOE PAGES

Iio, Masami; Xu, Qingjin; Nakamoto, Tatsushi; ...

2015-01-28

The High Energy Accelerator Research Organization (KEK) has been developing a Nb 3Al and Nb 3Sn subscale magnet to establish the technology for a high-field accelerator magnet. The development goals are a feasibility demonstration for a Nb 3Al cable and the technology acquisition of magnet fabrication with Nb 3Al superconductors. KEK developed two double-pancake racetrack coils with Rutherford-type cables composed of 28 Nb 3Al wires processed by rapid heating, quenching, and transformation in collaboration with the National Institute for Materials Science and the Fermi National Accelerator Laboratory. The magnet was fabricated to efficiently generate a high magnetic field in amore » minimum-gap common-coil configuration with two Nb 3Al coils sandwiched between two Nb 3Sn coils produced by the Lawrence Berkeley National Laboratory. A shell-based structure and a “bladder and key” technique have been used for adjusting coil prestress during both the magnet assembly and the cool down. In the first excitation test of the magnet at 4.5 K performed in June 2014, the highest quench current of the Nb 3Sn coil, i.e., 9667 A, was reached at 40 A/s corresponding to 9.0 T in the Nb 3Sn coil and 8.2 T in the Nb 3Al coil. The quench characteristics of the magnet were studied.« less

A novel alcohol/iron (III) fuel cell

NASA Astrophysics Data System (ADS)

Yi, Qingfeng; Zou, Tao; Zhang, Yuanyuan; Liu, Xiaoping; Xu, Guorong; Nie, Huidong; Zhou, Xiulin

2016-07-01

A novel alcohol fuel cell is constructed by using Fe3+ as the oxidation agent instead of the conventional O2. Various alcohols as the fuels are tested, including methanol, ethanol, n-propanol and iso-propanol. In this fuel cell, the anode catalysts tested are PdSn/β-cd-CNT, PdSn/CNT, Pd/β-cd-CNT, Pd/CNT and Pd/β-cd-C, prepared by using multi-walled carbon nanotube (CNT) and carbon powder (C), as well as β-cyclodexdrin (β-cd) modified CNT (β-cd-CNT) and β-cd modified C (β-cd-C), as the substrates to immobilize PdSn and Pd nanoparticles in glycol solvent. The as-synthesized PdSn/β-cd-CNT catalyst presents significantly higher electroactivity for alcohol oxidation than the conventional Pd/C catalyst. Fe3+ reduction reaction is carried out on the cathode made of carbon powder. The anolyte (alcohols in 1 mol L-1 NaOH) and catholyte (Fe3+ in 0.5 mol L-1 NaCl) are separated with a Nafion 117 membrane. Open circuit voltage (OCV) of the cell with the anode PdSn/β-cd-CNT is 1.14-1.22 V, depending upon the used alcohol. The maximum power densities with methanol, ethanol, n-propanol and iso-propanol fuels are 15.2, 16.1, 19.9 and 12.2 mW cm-2, respectively.

Scheduling the future NASA Space Network: Experiences with a flexible scheduling prototype

NASA Technical Reports Server (NTRS)

Happell, Nadine; Moe, Karen L.; Minnix, Jay

1993-01-01

NASA's Space Network (SN) provides telecommunications and tracking services to low earth orbiting spacecraft. One proposal for improving resource allocation and automating conflict resolution for the SN is the concept of flexible scheduling. In this concept, each Payload Operations Control Center (POCC) will possess a Space Network User POCC Interface (SNUPI) to support the development and management of flexible requests. Flexible requests express the flexibility, constraints, and repetitious nature of the user's communications requirements. Flexible scheduling is expected to improve SN resource utilization and user satisfaction, as well as reduce the effort to produce and maintain a schedule. A prototype testbed has been developed to better understand flexible scheduling as it applies to the SN. This testbed consists of a SNUPI workstation, an SN scheduler, and a flexible request language that conveys information between the two systems. All three are being evaluated by operations personnel. Benchmark testing is being conducted on the scheduler to quantify the productivity improvements achieved with flexible requests.

Microstructure and mechanical behavior of low-melting point Bi-Sn-In solder joints

NASA Astrophysics Data System (ADS)

Nguyen, Van Luong; Kim, Sang Hoon; Jeong, Jae Won; Lim, Tae-Soo; Yang, Dong-Yeol; Kim, Ki Bong; Kim, Young Ja; Lee, Jun Hong; Kim, Yong-Jin; Yang, Sangsun

2017-09-01

Ternary Bi-31.5Sn-25.0In solder has been proposed and studied for application in temperature-sensitive electronic components. In a Bi-31.5Sn- 25.0In solder joint, In was detected in an intermetallic compound (IMC) layer formed at the solder/Cu substrate interface with a thickness of 4.8 μm. The microstructure of the bulk solder consisted of Sn-rich phases distributed in Bi-rich phases with dispersion of In in both phases. Meanwhile, the nanomechanical properties of the Bi-31.5Sn-25.0In solder showed great strain rate sensitivity. To be specific, hardness increased from 9.91 MPa to 56.84 MPa as the strain rate increased in the range of (0.0005-0.125) s-1. The strain-rate sensitivity exponent ( m) was found to be 0.28, indicating that the excellent ductility was shown for the solder tested under the present conditions. [Figure not available: see fulltext.

An explanation for why it is difficult to form slush nitrogen from liquid nitrogen used previously for this purpose.

PubMed

Baker, Michael J; Denton, Travis T; Herr, Charles

2013-02-01

Slush nitrogen (SN) is used to avoid the Leidenfrost effect, which is problematic when using liquid nitrogen (LN). Slush nitrogen's usefulness has been demonstrated by its requirement for the successful cryopreservation of insect embryos. To convert LN to SN, typically, the pressure above a Dewar of LN is reduced, using a vacuum pump in a sealed system until conversion occurs. It has been observed that LN from a fresh tank will readily produce SN; however, repeated use of the same LN results in the inability to form SN in subsequent trials. The current experiments were designed to identify the cause of this phenomenon. The hypothesis is that gaseous oxygen from the surrounding, ambient air condenses and mixes with the LN to form a mixture with a lower freezing point and; therefore, prevents the formation of SN. The hypothesis was tested and found to be true. Copyright © 2012. Published by Elsevier Inc.

Triphenyltin derivatives of sulfanylcarboxylic esters.

PubMed

Casas, José S; Couce, María D; Sánchez, Agustín; Seoane, Rafael; Sordo, José; Perez-Estévez, Antonio; Vázquez-López, Ezequiel

2018-03-01

The reaction of 3-(aryl)-2-sulfanylpropenoic acids [H 2 xspa; x: p=3-phenyl-, f=3-(2-furyl)-, t=3-(2-thienyl)-] with methanol or ethanol gave the corresponding methyl (Hxspme) or ethyl (Hxspee) esters. The reaction of these esters (HL) with triphenyltin(IV) hydroxide gave compounds of the type [SnPh 3 L], which were isolated and characterized as solids by elemental analysis, IR spectroscopy and mass spectrometry and in solution by multinuclear ( 1 H, 13 C and 119 Sn) NMR spectroscopy. The structures of [SnPh 3 (pspme)], [SnPh 3 (fspme)] and [SnPh 3 (fspee)] were determined by X-ray diffractometry and the antimicrobial activity against E. coli, S. aureus, B. subtilis, P. aeruginosa, Resistant P. aeruginosa (a strain resistant to 'carbapenem'), and C. albicans was tested and the in vitro cytotoxic activity against the HeLa-229, A2780 and A2780cis cell lines was determined for all compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

Surface-sediment and hermit-crab contamination by butyltins in southeastern Atlantic estuaries after ban of TBT-based antifouling paints.

PubMed

Sant'Anna, B S; Santos, D M; Marchi, M R R; Zara, F J; Turra, A

2014-05-01

Butyltin (BT) contamination was evaluated in hermit crabs from 25 estuaries and in sediments from 13 of these estuaries along about 2,000 km of the Brazilian coast. BT contamination in hermit crabs ranged from 2.22 to 1,746 ng Sn g(-1) of DBT and 1.32 to 318 ng Sn g(-1) of TBT. In sediment samples, the concentration also varied widely, from 25 to 1,304 ng Sn g(-1) of MBT, from 7 to 158 ng Sn g(-1) of DBT, and from 8 to 565 ng Sn g(-1) of TBT. BTs are still being found in surface sediments and biota of the estuaries after the international and Brazilian bans, showing heterogeneous distribution among and within estuaries. Although hermit crabs were previously tested as an indicator of recent BT contamination, the results indicate the presence of contamination, probably from resuspension of BTs from deeper water of the estuary.

Performance comparison of low-temperature direct alcohol fuel cells with different anode catalysts

NASA Astrophysics Data System (ADS)

Zhou, W. J.; Zhou, B.; Li, W. Z.; Zhou, Z. H.; Song, S. Q.; Sun, G. Q.; Xin, Q.; Douvartzides, S.; Goula, M.; Tsiakaras, P.

Low-temperature polymer electrolyte membrane fuel cells directly fed by methanol and ethanol were investigated employing carbon supported Pt, PtSn and PtRu as anode catalysts, respectively. Employing Pt/C as anode catalyst, both direct methanol fuel cell (DMFC) and direct ethanol fuel cell (DEFC) showed poor performances even in presence of high Pt loading on anode. It was found that the addition of Ru or Sn to the Pt dramatically enhances the electro-oxidation of both methanol and ethanol. It was also found that the single cell adopting PtRu/C as anode shows better DMFC performance, while PtSn/C catalyst shows better DEFC performance. The single fuel cell using PtSn/C as anode catalyst at 90 °C shows similar power densities whenever fueled by methanol or ethanol. The cyclic voltammetry (CV) and single fuel cell tests indicated that PtRu is more suitable for DMFC while PtSn is more suitable for DEFC.

Oleophobic optical coating deposited by magnetron PVD

NASA Astrophysics Data System (ADS)

Bernt, D.; Ponomarenko, V.; Pisarev, A.

2016-09-01

Thin oxinitride films of Zn-Sn-O-N and Si-Al-O-N were deposited on glass by reactive magnetron sputtering at various nitrogen-to-oxygen ratios. Nitrogen added to oxygen led to decrease of the surface roughness and increase of oleophobic properties studied by the oil-drop test. The best oleophobity was obtained for Zn-Sn-O-N oxinitride at Zn:Sn=1:1 and N:O=1:2. Improved oleophobic properties were also demonstrated if the oxinitride film was deposited on top of the multilayer coating as the final step in the industrial cycle of production of energy efficient glass.

Fracture resistance of Ti-5Al-2.5Sn extra-low interstitial castings

NASA Technical Reports Server (NTRS)

Fiftal, C. F.; Bolstad, D. A.; Misra, M. S.

1978-01-01

Fracture toughness and cyclic crack propagation data for Ti-5Al-2.5Sn extra-low interstitial (ELI) castings, 0.51 and 2.54 cm (0.20 and 1.00 in.) thick, at 394, 294, 77, and 20 K (250, 70, -320, and -423 F), are presented. Both surface flaw and compact tension geometries were tested. Comparison is made with other titanium alloys in both wrought and cast forms. Crack propagation resistance is comparable to wrought Ti-5Al-2.5Sn ELI, even with the extremely coarse as-cast grain size encountered.

Quench Protection Studies of 11T Nb$$_3$$Sn Dipole Models for LHC Upgrades

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

Zlobin, Alexander; Chlachidze, Guram; Nobrega, Alfred

CERN and FNAL are developing 11 T Nb3Sn dipole magnets for the LHC collimation system upgrade. Due to the large stored energy, protection of these magnets during a quench is a challenging problem. This paper reports the results of experimental studies of key quench protection parameters including longitudinal and radial quench propagation in the coil, coil heating due to a quench, and energy extraction and quench-back effect. The studies were performed using a 1 m long 11 T Nb3Sn dipole coil tested in a magnetic mirror configuration.

High-cycle fatigue characterization of titanium 5Al-2.5Sn alloy

NASA Technical Reports Server (NTRS)

Mahfuz, H.; Xin, Yu T.; Jeelani, S.

1993-01-01

High-cycle fatigue behavior of titanium 5Al 2.5Sn alloy at room temperature has been studied. S-N curve characterization is performed at different stress ratios ranging from 0 to 0.9 on a subsized fatigue specimen. Both two-stress and three-stress level tests are conducted at different stress ratios to study the cumulative fatigue damage. Life prediction techniques of linear damage rule, double linear damage rule and damage curve approaches are applied, and results are compared with the experimental data. The agreement between prediction and experiment is found to be excellent.

Electromigration in solder joints and solder lines

NASA Astrophysics Data System (ADS)

Gan, H.; Choi, W. J.; Xu, G.; Tu, K. N.

2002-06-01

Electromigration may affect the reliability of flip-chip solder joints. Eutectic solder is a two-phase alloy, so its electromigration behavior is different from that in aluminum or copper interconnects. In addition, a flipchip solder joint has a built-in currentcrowding configuration to enhance electromigration failure. To better understand electromigration in SnPb and lead-free solder alloys, the authors prepared solder lines in v-grooves etched on Si (001). This article discusses the results of those tests and compares the electromigration failure modes of eutectic SnPb and SnAgCu flip-chip solder joints along with the mean-timeto-failure.

Effective conversion of irinotecan to SN-38 after intratumoral drug delivery to an intracranial murine glioma model in vivo. Laboratory investigation.

PubMed

Wang, Weijun; Ghandi, Alex; Liebes, Leonard; Louie, Stan G; Hofman, Florence M; Schönthal, Axel H; Chen, Thomas C

2011-03-01

Irinotecan (CPT-11), a topoisomerase I inhibitor, is a cytotoxic agent with activity against malignant gliomas and other tumors. After systemic delivery, CPT-11 is converted to its active metabolite, SN-38, which displays significantly higher cytotoxic potency. However, the achievement of therapeutically effective plasma levels of CPT-11 and SN-38 is seriously complicated by variables that affect drug metabolism in the liver. Thus the capacity of CPT-11 to be converted to the active SN38 intratumorally in gliomas was addressed. For in vitro studies, 2 glioma cell lines, U87 and U251, were tested to determine the cytotoxic effects of CPT-11 and SN-38 in a dose-dependent manner. In vivo studies were performed by implanting U87 intracranially into athymic/nude mice. For a period of 2 weeks, SN-38, CPT-11, or vehicle was administered intratumorally by means of an osmotic minipump. One series of experiments measured the presence of SN-38 or CPT-11 in the tumor and surrounding brain tissues after 2 weeks' exposure to the drug. In a second series of experiments, after 2 weeks' exposure to the drug, the animals were maintained, in the absence of drug, until death. The survival curves were then calculated. The results show that the animals that had CPT-11 delivered intratumorally by the minipump expressed SN-38 in vivo. Furthermore, both CPT-11 and SN-38 accumulated at higher levels in tumor tissues compared with uninvolved brain. Intratumoral delivery of CPT-11 or SN-38 extended the average survival time of tumor-bearing animals from 22 days to 46 and 65 days, respectively. These results demonstrate that intratumorally administered CPT-11 can be effectively converted to SN-38 and this method of drug delivery is effective in extending the survival time of animals bearing malignant gliomas.

Enhanced photodegradation activity of methyl orange over Ag{sub 2}CrO{sub 4}/SnS{sub 2} composites under visible light irradiation

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

Luo, Jin, E-mail: lj328520504@126.com; Zhou, Xiaosong; Ma, Lin

Highlights: • Novel visible-light-driven Ag{sub 2}CrO{sub 4}/SnS{sub 2} composites are synthesized. • Ag{sub 2}CrO{sub 4}/SnS{sub 2} exhibits higher photocatalytic activity than pure Ag{sub 2}CrO{sub 4} and SnS{sub 2}. • Ag{sub 2}CrO{sub 4}/SnS{sub 2} exhibits excellent stability for the photodegradation of MO. • The possible photocatalytic mechanism was discussed in detail. - Abstract: Novel Ag{sub 2}CrO{sub 4}/SnS{sub 2} composites were prepared by a simple chemical precipitation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The visible light photocatalytic tests showed that the Ag{sub 2}CrO{sub 4}/SnS{sub 2} compositesmore » enhanced photocatalytic activities for the photodegradation of methyl orange (MO) under visible light irradiation (λ > 420 nm), and the optimum rate constant of Ag{sub 2}CrO{sub 4}/SnS{sub 2} at a weight content of 1.0% Ag{sub 2}CrO{sub 4} for the degradation of MO was 2.2 and 1.5 times larger than that of pure Ag{sub 2}CrO{sub 4} and SnS{sub 2}, respectively. The improved activity could be attributed to high separation efficiency of photogenerated electrons-hole pairs on the interface of Ag{sub 2}CrO{sub 4} and SnS{sub 2}, which arised from the synergistic effect between Ag{sub 2}CrO{sub 4} and SnS{sub 2}. Moreover, the possible photocatalytic mechanism with superoxide radical anions and holes species as the main reactive species in photocatalysis process was proposed on the basis of experimental results.« less

Investigation of microstructural and physical characteristics of nano composite tin oxide-doped Al3+ in Zn2+ based composite coating by DAECD technique

NASA Astrophysics Data System (ADS)

Anawe, P. A. L.; Fayomi, O. S. I.; Popoola, A. P. I.

In other to overcome the devastating deterioration of mild steel in service, Zn-based embedded Al/SnO2 composite coatings have been considered as reinforcing alternative replacements to the more traditional deposition for improved surface properties by using Dual Anode Electrolytic Co-deposition (DAECD) technique from chloride bath. The structural characterization of the starting materials and deposited coating are evaluated using scanning electron microscopy (SEM), equipped with energy dispersive X-ray spectroscopy (EDX) elemental analysis and atomic force microscope (AFM). The hardness behaviour, wear and intermetallic distribution was examined by diamond based microhardness tester, CETR reciprocating sliding test rig and X-ray diffractometer (XRD) respectively. The corrosion properties of the developed coating were examined in 3.5% NaCl. The microstructure of the deposited sample obtained at 7% SnO2, revealed fine-grains deposit of the Al/SnO2 on the mild steel surface. The results showed that the Al/SnO2 strengthening alloy plays a significant role in impelling the wear and corrosion behaviour of Zn-Al/SnO2 coatings in an aggressive saline environment. Interestingly Zn-30Al-7Sn-chloride showed the highest wear and improved corrosion resistance due to Al/SnO2 oxide passive film that forms during anodic polarization. This work established that co-deposition of mild steel with Al/SnO2 is auspicious in increasing the anti-wear and corrosion progression.

Statistical Analysis of the Processes Controlling Choline and Ethanolamine Glycerophospholipid Molecular Species Composition

PubMed Central

Kiebish, Michael A.; Yang, Kui; Han, Xianlin; Gross, Richard W.; Chuang, Jeffrey

2012-01-01

The regulation and maintenance of the cellular lipidome through biosynthetic, remodeling, and catabolic mechanisms are critical for biological homeostasis during development, health and disease. These complex mechanisms control the architectures of lipid molecular species, which have diverse yet highly regulated fatty acid chains at both the sn1 and sn2 positions. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) serve as the predominant biophysical scaffolds in membranes, acting as reservoirs for potent lipid signals and regulating numerous enzymatic processes. Here we report the first rigorous computational dissection of the mechanisms influencing PC and PE molecular architectures from high-throughput shotgun lipidomic data. Using novel statistical approaches, we have analyzed multidimensional mass spectrometry-based shotgun lipidomic data from developmental mouse heart and mature mouse heart, lung, brain, and liver tissues. We show that in PC and PE, sn1 and sn2 positions are largely independent, though for low abundance species regulatory processes may interact with both the sn1 and sn2 chain simultaneously, leading to cooperative effects. Chains with similar biochemical properties appear to be remodeled similarly. We also see that sn2 positions are more regulated than sn1, and that PC exhibits stronger cooperative effects than PE. A key aspect of our work is a novel statistically rigorous approach to determine cooperativity based on a modified Fisher's exact test using Markov Chain Monte Carlo sampling. This computational approach provides a novel tool for developing mechanistic insight into lipidomic regulation. PMID:22662143

Study of the protective effect of ascorbic acid against the toxicity of stannous chloride on oxidative damage, antioxidant enzymes and biochemical parameters in rabbits.

PubMed

Yousef, M I; Awad, T I; Elhag, F A; Khaled, F A

2007-06-25

Stannous chloride (SnCl2) is a reducing chemical agent used in several man-made products. SnCl2 can generate reactive oxygen species (ROS). Therefore, the present study has been carried out to investigate the antioxidant action of l-ascorbic acid (AA) in minimizing SnCl2 toxicity on lipid peroxidation, antioxidant enzyme, and biochemical parameters in male New Zealand white rabbits. Animals were assigned to one of four treatment groups: 0mg AA and 0mg SnCl2/kg BW (control); 40 mg AA/kg BW; 20mg SnCl2/kg BW; 20mg SnCl2 plus 40 mg AA/kg BW. Rabbits were orally administered the respective doses every other day for 12 weeks. Results obtained showed that SnCl2 significantly (P<0.05) induced thiobarbituric acid-reactive substances (TBARS; the marker of lipid peroxidation) in plasma, while the activities of glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT), and the level of sulfhydryl groups (SH-group) were decreased (P<0.05) in blood plasma. Aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (AlP), acid phosphatase (AcP) and lactate dehydrogenase (LDH) activities were decreased (P<0.05). Stannous chloride significantly (P<0.05) increased the levels of plasma total lipid (TL), cholesterol, triglyceride (TG), low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL), glucose, urea and total bilirubin. On the other hand, the level of plasma high-density lipoprotein (HDL), total protein (TP), albumin (A) and globulin (G) were significantly (P<0.05) decreased. Ascorbic acid alone significantly decreased the levels of TBARS, lipids and urea, and increased the activities of GST, SOD and CAT, and the levels of SH-group and proteins. While the rest of the tested parameters were not affected. Also, the presence of AA with SnCl2 alleviated its harmful effects on most of the tested parameters. Therefore, the present results revealed that treatment with AA could minimize the toxic effects of stannous chloride.

Apatite Formation and Biocompatibility of a Low Young’s Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water

PubMed Central

Tanaka, Hidetatsu; Mori, Yu; Noro, Atsushi; Kogure, Atsushi; Kamimura, Masayuki; Yamada, Norikazu; Hanada, Shuji; Masahashi, Naoya; Itoi, Eiji

2016-01-01

Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young’s modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young’s modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank’s solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion. PMID:26914329

Screen-printed SnO2/CNT quasi-solid-state gel-electrolyte supercapacitor

NASA Astrophysics Data System (ADS)

Kuok, Fei-Hong; Liao, Chen-Yu; Chen, Chieh-Wen; Hao, Yu-Chuan; Yu, Ing-Song; Chen, Jian-Zhang

2017-11-01

This study investigates a quasi-solid-state gel-electrolyte supercapacitor fabricated with nanoporous SnO2/CNT nanocomposite electrodes and a polyvinyl alcohol/sulfuric acid (PVA/H2SO4) gel electrolyte. First, pastes containing SnO2 nanoparticles, CNTs, ethyl cellulose, and terpineol are screen-printed onto carbon cloth. A tube furnace is then used for calcining the SnO2/CNT electrodes on carbon cloth. After furnace-calcination, the wettability of SnO2/CNT significantly improved; furthermore, the XPS analysis shows that number of C-O bond and oxygen content significantly decrease after furnace-calcination owing to the burnout of the ethyl cellulose by the furnace calcination processes. The furnace-calcined SnO2/CNT electrodes sandwich the PVA/H2SO4 gel electrolyte to form a supercapacitor. The fabricated supercapacitor exhibits an areal capacitance of 5.61 mF cm-2 when flat and 5.68 mF cm-2 under bending with a bending radius (R) of 1.0 cm. After a 1000 cycle stability test, the capacitance retention rates of the supercapacitor are 96% and 97% when flat and under bending (R  =  1.0 cm), respectively.

Microstructure and properties of thermally sprayed Al-Sn-based alloys for plain bearing applications

NASA Astrophysics Data System (ADS)

Marrocco, T.; Driver, L. C.; Harris, S. J.; McCartney, D. G.

2006-12-01

Al-Sn plain bearings for automotive applications traditionally comprise a multilayer structure. Conventionally, bearing manufacturing involves casting the Al-Sn alloy and roll-bonding to a steel backing strip. Recently, high-velocity oxyfuel (HVOF) thermal spraying has been used as a novel alternative manufacturing route. The present project extends previous work on ternary Al-Sn-Cu alloys to quaternary systems, which contain specific additions for potentially enhanced properties. Two alloys were studied in detail, namely, Al-20wt.%Sn-1wt.%Cu-2wt.%Ni and Al-20wt.%Sn-1wt.%Cu-7wt.%Si. This article will describe the microstructural evolution of these alloys following HVOF spraying onto steel substrates and subsequent heat treatment. The microstructures of powders and coatings were investigated by scanning electron microscopy, and the phases were identified by x-ray diffraction. Coating microhardnesses were determined under both as-sprayed and heat-treated conditions, and by the differences related to the microstructures that developed. Finally, the wear behavior of the sprayed and heat-treated coatings in hot engine oil was measured using an industry standard test and was compared with that of previous work on a ternary alloy.

The Shear Strength and Fracture Behavior of Sn-Ag- xSb Solder Joints with Au/Ni-P/Cu UBM

NASA Astrophysics Data System (ADS)

Lee, Hwa-Teng; Hu, Shuen-Yuan; Hong, Ting-Fu; Chen, Yin-Fa

2008-06-01

This study investigates the effects of Sb addition on the shear strength and fracture behavior of Sn-Ag-based solders with Au/Ni-P/Cu underbump metallization (UBM) substrates. Sn-3Ag- xSb ternary alloy solder joints were prepared by adding 0 wt.% to 10 wt.% Sb to a Sn-3.5Ag alloy and joining them with Au/Ni-P/Cu UBM substrates. The solder joints were isothermally stored at 150°C for up to 625 h to study their microstructure and interfacial reaction with the UBM. Single-lap shear tests were conducted to evaluate the mechanical properties, thermal resistance, and failure behavior. The results show that UBM effectively suppressed intermetallic compound (IMC) formation and growth during isothermal storage. The Sb addition helped to refine the Ag3Sn compounds, further improving the shear strength and thermal resistance of the solders. The fracture behavior evolved from solder mode toward the mixed mode and finally to the IMC mode with increasing added Sb and isothermal storage time. However, SnSb compounds were found in the solder with 10 wt.% Sb; they may cause mechanical degradation of the solder after long-term isothermal storage.

Enhanced photovoltaic properties in dye sensitized solar cells by surface treatment of SnO2 photoanodes

PubMed Central

Basu, Kaustubh; Benetti, Daniele; Zhao, Haiguang; Jin, Lei; Vetrone, Fiorenzo; Vomiero, Alberto; Rosei, Federico

2016-01-01

We report the fabrication and testing of dye sensitized solar cells (DSSC) based on tin oxide (SnO2) particles of average size ~20 nm. Fluorine-doped tin oxide (FTO) conducting glass substrates were treated with TiOx or TiCl4 precursor solutions to create a blocking layer before tape casting the SnO2 mesoporous anode. In addition, SnO2 photoelectrodes were treated with the same precursor solutions to deposit a TiO2 passivating layer covering the SnO2 particles. We found that the modification enhances the short circuit current, open-circuit voltage and fill factor, leading to nearly 2-fold increase in power conversion efficiency, from 1.48% without any treatment, to 2.85% achieved with TiCl4 treatment. The superior photovoltaic performance of the DSSCs assembled with modified photoanode is attributed to enhanced electron lifetime and suppression of electron recombination to the electrolyte, as confirmed by electrochemical impedance spectroscopy (EIS) carried out under dark condition. These results indicate that modification of the FTO and SnO2 anode by titania can play a major role in maximizing the photo conversion efficiency. PMID:26988622

Using Ag/Ag2O/SnO2 Nanocomposites to Remove Malachite Green by a Photocatalytic Process

NASA Astrophysics Data System (ADS)

Taufik, A.; Paramarta, V.; Prakoso, S. P.; Saleh, R.

2017-03-01

Silver/silver oxide/tin oxide nanocomposites of various weight ratios were synthesized using a microwave-assisted method. The Ag/Ag2O:SnO2 nanoparticle weight ratios used were 25:75, 50:50, and 75:25. All samples were characterized using X-ray diffraction, UV-Vis spectroscopy, Differential Scanning Calorimetry and Thermogravimetric Analysis (TGA). The Ag/Ag2O/SnO2 nanocomposites contained cubic structures provided by the Ag and Ag2O and tetragonal structures provided by the SnO2. The silver resulted in surface plasmon resonance (SPR) at a wavelength of about 435 nm. The silver oxide material was transformed into pure Ag at a temperature of about 370 °C The photocatalytic activity was tested on the degradation of malachite green (MG) from an aqueous solution. The results showed that Ag/Ag2O/SnO2 at a ratio of 50:50 exhibited the best photocatalytic performance for degrading MG under visible-light irradiation. The degradation of MG using Ag/Ag2O/SnO2 nanocomposites followed pseudo first-order kinetic reactions, and electron holes were found to be the main species acting on the degradation process.

Intermetallic Compounds Formed in Sn-20In-2.8Ag Solder BGA Packages with Ag/Cu Pads

NASA Astrophysics Data System (ADS)

Jain, C. C.; Wang, S. S.; Huang, K. W.; Chuang, T. H.

2009-03-01

The interfacial reactions in a Sn-20In-2.8Ag solder ball grid array (BGA) package with immersion Ag surface finish are investigated. After reflow, the Ag thin film dissolves quickly into the solder matrix, and scallop-shaped intermetallic layers, with compositions of (Cu0.98Ag0.02)6(In0.59Sn0.41)5, appear at the interfaces between Sn-20In-2.8Ag solder ball and Cu pad. No evident growth of the (Cu0.98Ag0.02)6(Sn0.59In0.41)5 intermetallic compounds was observed after prolonged aging at 100 °C. However, the growth accelerated at 150 °C, with more intermetallic scallops floating into the solder matrix. The intermetallic thickness versus the square root of reaction time ( t 1/2) shows a linear relation, indicating that the growth of intermetallic compounds is diffusion-controlled. Ball shear tests show that the strength of Sn-20In-2.8Ag solder joints after reflow is 4.4 N, which increases to 5.18 N and 5.14 N after aging at 100 and 150 °C, respectively.

Properties of ternary Sn-Ag-Bi solder alloys. Part 2: Wettability and mechanical properties analyses

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

Vianco, P.T.; Rejent, J.A.

1999-10-01

Bismuth additions of 1% to 10% were made to the 96.5Sn-3.5Ag (wt.%) alloy in a study to develop a Sn-Ag-Bi ternary composition. Thermal properties and microstructural analyses of selected alloy compositions were reported in Part 1. Wettability and mechanical properties are described in this paper. Contact angle measurements demonstrated that Bi additions improved wetting/spreading performance on Cu; a minimum contact angle of 31 {+-} 4{degree} was observed with 4.83 wt.% Bi addition. Increasing the Bi content of the ternary alloy raised the Cu/solder/Cu solder joint shear strength to 81 MPa as determined by the ring-and-plug tests. TEM analysis of themore » 91.84Sn-3.33Ag-4.83Bi composition presented in Part 1 indicated that the strength improvement was attributed to solid-solution and precipitation strengthening effects by the Bi addition residing in the Sn-rich phase. Microhardness measurements of the Sn-Ag-Bi alloy, as a function of Bi content, reached maximum values of 30 (Knoop, 50 g) and 110 (Knoop, 5g) for Bi contents greater than approximately 4--5 wt.%.« less

Potential secondary poisoning risks to non-targets from a sodium nitrite toxic bait for invasive wild pigs.

PubMed

Snow, Nathan P; Foster, Justin A; VanNatta, Eric H; Horak, Katherine E; Humphrys, Simon T; Staples, Linton D; Hewitt, David G; VerCauteren, Kurt C

2018-01-01

An acute and orally delivered toxic bait containing micro-encapsulated sodium nitrite (MESN), is under development to provide a novel and humane technology to help curtail damage caused by invasive wild pigs (Sus scrofa). We evaluated potential secondary risks for non-target species by: testing whether four different types of micro-encapsulation coatings could reduce vomiting by invasive wild pigs, testing the levels of residual sodium nitrite (SN) in tissues of invasive wild pigs, testing the environmental persistence of SN in vomitus, and conducting a risk assessment for scavengers. Micro-encapsulation coatings did not affect the frequency of vomiting. We identified no risk of secondary poisoning for non-target scavengers that consume muscle, eyes, and livers of invasive wild pig carcasses because residual SN from the toxic bait was not detected in those tissues. The risk of secondary poisoning from consuming vomitus appeared low because ∼90% of the SN was metabolized or broken down prior to vomiting, and continued to degrade after being exposed to the environment. Secondary poisoning could occur for common scavengers that consume approximately ≥15% of their daily dietary requirements of digestive tract tissues or undigested bait from carcasses of invasive wild pigs in a rapid, single-feeding event. The likelihood of this occurring in a natural setting is unknown. The digestive tracts of poisoned invasive wild pigs contained an average of ∼4.35 mg/g of residual SN. Data from this study suggest no risks of secondary poisoning for non-target species (including humans) that consume muscle, liver, or eyes of invasive wild pigs poisoned with a MESN toxic bait. More species-specific testing for scavengers that consume digestive tract tissues and undigested bait is needed to reduce uncertainty about these potential risks. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Multivariate Qst–Fst Comparisons: A Neutrality Test for the Evolution of the G Matrix in Structured Populations

PubMed Central

Martin, Guillaume; Chapuis, Elodie; Goudet, Jérôme

2008-01-01

Neutrality tests in quantitative genetics provide a statistical framework for the detection of selection on polygenic traits in wild populations. However, the existing method based on comparisons of divergence at neutral markers and quantitative traits (Qst–Fst) suffers from several limitations that hinder a clear interpretation of the results with typical empirical designs. In this article, we propose a multivariate extension of this neutrality test based on empirical estimates of the among-populations (D) and within-populations (G) covariance matrices by MANOVA. A simple pattern is expected under neutrality: D = 2Fst/(1 − Fst)G, so that neutrality implies both proportionality of the two matrices and a specific value of the proportionality coefficient. This pattern is tested using Flury's framework for matrix comparison [common principal-component (CPC) analysis], a well-known tool in G matrix evolution studies. We show the importance of using a Bartlett adjustment of the test for the small sample sizes typically found in empirical studies. We propose a dual test: (i) that the proportionality coefficient is not different from its neutral expectation [2Fst/(1 − Fst)] and (ii) that the MANOVA estimates of mean square matrices between and among populations are proportional. These two tests combined provide a more stringent test for neutrality than the classic Qst–Fst comparison and avoid several statistical problems. Extensive simulations of realistic empirical designs suggest that these tests correctly detect the expected pattern under neutrality and have enough power to efficiently detect mild to strong selection (homogeneous, heterogeneous, or mixed) when it is occurring on a set of traits. This method also provides a rigorous and quantitative framework for disentangling the effects of different selection regimes and of drift on the evolution of the G matrix. We discuss practical requirements for the proper application of our test in empirical studies and potential extensions. PMID:18245845

Observations of SN 2015F Suggest a Correlation between the Intrinsic Luminosity of Type Ia Supernovae and the Shape of Their Light Curves >900 Days after Explosion

NASA Astrophysics Data System (ADS)

Graur, Or; Zurek, David R.; Rest, Armin; Seitenzahl, Ivo R.; Shappee, Benjamin J.; Fisher, Robert; Guillochon, James; Shara, Michael M.; Riess, Adam G.

2018-06-01

The late-time light curves of Type Ia supernovae (SNe Ia), observed >900 days after explosion, present the possibility of a new diagnostic for SN Ia progenitor and explosion models. First, however, we must discover what physical process (or processes) leads to the slow-down of the light curve relative to a pure 56Co decay, as observed in SNe 2011fe, 2012cg, and 2014J. We present Hubble Space Telescope observations of SN 2015F, taken ≈600–1040 days past maximum light. Unlike those of the three other SNe Ia, the light curve of SN 2015F remains consistent with being powered solely by the radioactive decay of 56Co. We fit the light curves of these four SNe Ia in a consistent manner and measure possible correlations between the light-curve stretch—a proxy for the intrinsic luminosity of the SN—and the parameters of the physical model used in the fit. We propose a new, late-time Phillips-like correlation between the stretch of the SNe and the shape of their late-time light curves, which we parameterize as the difference between their pseudo-bolometric luminosities at 600 and 900 days: ΔL 900 = log(L 600/L 900). Our analysis is based on only four SNe, so a larger sample is required to test the validity of this correlation. If true, this model-independent correlation provides a new way to test which physical process lies behind the slow-down of SN Ia light curves >900 days after explosion, and, ultimately, fresh constraints on the various SN Ia progenitor and explosion models.

Nanoindentation on SnAgCu lead-free solder joints and analysis

NASA Astrophysics Data System (ADS)

Xu, Luhua; Pang, John H. L.

2006-12-01

The lead-free SnAgCu (SAC) solder joint on copper pad with organic solderability preservative (Cu-OSP) and electroless nickel and immersion gold (ENIG) subjected to thermal testing leads to intermetallic growth. It causes corresponding reliability concerns at the interface. Nanoindentation characterization on SnAgCu solder alloy, intermetallic compounds (IMCs), and the substrates subjected to thermal aging is reported. The modulus and hardness of thin IMC layers were measured by nanoindentation continuous stiffness measurement (CSM) from planar IMC surface. When SAC/Ni(Au) solder joints were subject to thermal aging, the Young’s modulus of the NiCuSn IMC at the SAC/ENIG specimen changed from 207 GPa to 146 GPa with different aging times up to 500 h. The hardness decreased from 10.0 GPa to 7.3 GPa. For the SAC/Cu-OSP reaction couple, the Young’s modulus of Cu6Sn5 stayed constant at 97.0 GPa and hardness about 5.7 GPa. Electron-probe microanalysis (EPMA) was used to thermal aging. The creep effect on the measured result was analyzed when measuring SnAgCu solder; it was found that the indentation penetration, and thus the hardness, is loading rate dependent. With the proposed constant P/P experiment, a constant indentation strain rate h/h and hardness could be achieved. The log-log plot of indentation strain rate versus hardness for the data from the constant P/P experiments yields a slope of 7.52. With the optimized test method and CSM Technique, the Modulus of SAC387 solder alloy and all the layers in a solder joint were investigated.

Mechanical Properties and Microstructure Investigation of Lead Free Solder

NASA Technical Reports Server (NTRS)

Wang, Qing; Gail, William F.; Johnson, R. Wayne; Strickland, Mark; Blanche, Jim

2005-01-01

While the electronics industry appears to be focusing on Sn-Ag-Cu as the alloy of choice for lead free electronics assembly, ,the exact composition varies by geographic region, supplier and user. Add to that dissolved copper and silver from the printed circuit board traces and surface finish, and there can be significant variation in the final solder joint composition. A systematic study of the mechanical and microstructural properties of Sn-Ag-Cu alloys with Ag varying from 2wt% to 4wt% and Cu varying from 0.5wt% to lSwt%, was undertaken in this research study. Different sample preparation techniques (water quenched, oil quenched and water quenched followed by reflow) were explored and the resulting microstructure compared to that of a typical reflowed lead free chip scale package (CSP) solder joint. Tensile properties (modulus, 0.2% yield strength and the ultimate tensile strength) and creep behavior of selected alloy compositions (Sn-4Ag-1 X u , Sn-4Ag-OSCu, Sn- 2Ag-1 X u , Sn-2Ag-OSCu, Sn-3.5Ag-O.SCu) were determined for three conditions: as- cast; aged for 100 hours at 125OC; and aged for 250 hours at 125OC. There was no significant difference in Young's Modulus as a function of alloy composition. After an initial decrease in modulus after 100 hours at 125"C, there was an insignificant change with further aging. The distribution of 0.2% strain yield stress and ultimate tensile strength as a function of alloy composition was more significant and decreased with aging time and temperature. The microstructures of these alloys were examined using light and scanning electron microscopy (LM and SEM) respectively and SEM based energy dispersive x-ray spectroscopy (EDS). Fracture surface and cross-section analysis were performed on the specimens after creep testing. The creep testing results and the effect of high temperature aging on mechanical properties is presented for the oil quenched samples. In general the microstructure of oil quenched specimen exhibited a eutectic region of Sn with moderately dispersed Ag3Sn intermetallic, surrounded by a dendritic Sn-rich phase. The SEM images of the fracture surface indicated the presence of a tough shear surface at the initial cavity break area and a break line in the middle of specimen along the failure direction. A hyperbolic-sine creep model was adopted and used to fit the creep experiment data. The effect on the mechanical properties by adding the quaternary element bismuth to the Sn-3.5Ag-0.8Cu alloy was measured and compared with the mechanical properties of the ternary alloys. The results of this research study provide necessary data for the modeling of solder joint reliability for a range of Sn-Ag-Cu compositions and a baseline for evaluating the effects of subsequent quaternary additions.

Effect of Sn addition on the corrosion behavior of Ti-7Cu-Sn cast alloys for biomedical applications.

PubMed

Tsao, L C

2015-01-01

The aim of this study was to investigate the effects of Sn content on the microstructure and corrosion resistance of Ti7CuXSn (x=0-5 wt.%) samples. The corrosion tests were carried out in 0.9 wt.% NaCl solution at 25 °C. The electrochemical corrosion behavior of the Ti7CuXSn alloy samples was evaluated using potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and equivalent circuit analysis. The resulting impedance parameters and polarization curves showed that adding Sn improved the electrochemical corrosion behavior of the Ti7CuXSn alloy. The Ti7CuXSn alloy samples were composed of a dual-layer oxide consisting of an inner barrier layer and an outer porous layer. Copyright © 2014 Elsevier B.V. All rights reserved.

Electrical and mechanical properties of Sn-5wt.%Sb alloy with annealing temperature

NASA Astrophysics Data System (ADS)

Said Gouda, El; Ahmed, E. M.; Saad Allah, F. A.

2009-01-01

A binary Sn-5wt.%Sb solder alloy was chosen as a potential alternative to Sn-Pb solder alloy to be subjected to many studies. It was casted from the liquid state, cold drawn into wires of 1 mm diameters. The study includes the structure, electrical resistivity, tensile strength, hardness and indentation creep behavior using XRD, four probes electrical circuit, conventional tensile testing machine, Vickers microhardness tester, respectively. These properties were carried out for the cold worked alloy and after annealing at 393 and 473 K for 60 min. It was found that annealed samples exhibit more precipitations of the intermetallic compounds SnSb, higher lattice parameters and higher crystallite size, while have lower lattice-strain induced due to the cold working process. These structural changes greatly affect the electrical resistivity and mechanical properties of this alloy.

SnRK1 activates autophagy via the TOR signaling pathway in Arabidopsis thaliana

DOE PAGES

Soto-Burgos, Junmarie; Bassham, Diane C.

2017-08-04

Autophagy is a degradation process in which cells break down and recycle their cytoplasmic contents when subjected to environmental stress or during cellular remodeling. The Arabidopsis thaliana SnRK1 complex is a protein kinase that senses changes in energy levels and triggers downstream responses to enable survival. Its mammalian ortholog, AMPK, and yeast ortholog, Snf-1, activate autophagy in response to low energy conditions. We therefore hypothesized that SnRK1 may play a role in the regulation of autophagy in response to nutrient or energy deficiency in Arabidopsis. To test this hypothesis, we determined the effect of overexpression or knockout of the SnRK1more » catalytic subunit KIN10 on autophagy activation by abiotic stresses, including nutrient deficiency, salt, osmotic, oxidative, and ER stress. While wild-type plants had low basal autophagy activity in control conditions, KIN10 overexpression lines had increased autophagy under these conditions, indicating activation of autophagy by SnRK1. A kin10 mutant had a basal level of autophagy under control conditions similar to wild-type plants, but activation of autophagy by most abiotic stresses was blocked, indicating that SnRK1 is required for autophagy induction by a wide variety of stress conditions. In mammals, TOR is a negative regulator of autophagy, and AMPK acts to activate autophagy both upstream of TOR, by inhibiting its activity, and in a parallel pathway. Inhibition of Arabidopsis TOR leads to activation of autophagy; inhibition of SnRK1 did not block this activation. Furthermore, an increase in SnRK1 activity was unable to induce autophagy when TOR was also activated. The results presented here demonstrate that SnRK1 acts upstream of TOR in the activation of autophagy in Arabidopsis.« less

SnRK1 activates autophagy via the TOR signaling pathway in Arabidopsis thaliana

PubMed Central

Soto-Burgos, Junmarie

2017-01-01

Autophagy is a degradation process in which cells break down and recycle their cytoplasmic contents when subjected to environmental stress or during cellular remodeling. The Arabidopsis thaliana SnRK1 complex is a protein kinase that senses changes in energy levels and triggers downstream responses to enable survival. Its mammalian ortholog, AMPK, and yeast ortholog, Snf-1, activate autophagy in response to low energy conditions. We therefore hypothesized that SnRK1 may play a role in the regulation of autophagy in response to nutrient or energy deficiency in Arabidopsis. To test this hypothesis, we determined the effect of overexpression or knockout of the SnRK1 catalytic subunit KIN10 on autophagy activation by abiotic stresses, including nutrient deficiency, salt, osmotic, oxidative, and ER stress. While wild-type plants had low basal autophagy activity in control conditions, KIN10 overexpression lines had increased autophagy under these conditions, indicating activation of autophagy by SnRK1. A kin10 mutant had a basal level of autophagy under control conditions similar to wild-type plants, but activation of autophagy by most abiotic stresses was blocked, indicating that SnRK1 is required for autophagy induction by a wide variety of stress conditions. In mammals, TOR is a negative regulator of autophagy, and AMPK acts to activate autophagy both upstream of TOR, by inhibiting its activity, and in a parallel pathway. Inhibition of Arabidopsis TOR leads to activation of autophagy; inhibition of SnRK1 did not block this activation. Furthermore, an increase in SnRK1 activity was unable to induce autophagy when TOR was also activated. These results demonstrate that SnRK1 acts upstream of TOR in the activation of autophagy in Arabidopsis. PMID:28783755

SnRK1 activates autophagy via the TOR signaling pathway in Arabidopsis thaliana

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

Soto-Burgos, Junmarie; Bassham, Diane C.

Autophagy is a degradation process in which cells break down and recycle their cytoplasmic contents when subjected to environmental stress or during cellular remodeling. The Arabidopsis thaliana SnRK1 complex is a protein kinase that senses changes in energy levels and triggers downstream responses to enable survival. Its mammalian ortholog, AMPK, and yeast ortholog, Snf-1, activate autophagy in response to low energy conditions. We therefore hypothesized that SnRK1 may play a role in the regulation of autophagy in response to nutrient or energy deficiency in Arabidopsis. To test this hypothesis, we determined the effect of overexpression or knockout of the SnRK1more » catalytic subunit KIN10 on autophagy activation by abiotic stresses, including nutrient deficiency, salt, osmotic, oxidative, and ER stress. While wild-type plants had low basal autophagy activity in control conditions, KIN10 overexpression lines had increased autophagy under these conditions, indicating activation of autophagy by SnRK1. A kin10 mutant had a basal level of autophagy under control conditions similar to wild-type plants, but activation of autophagy by most abiotic stresses was blocked, indicating that SnRK1 is required for autophagy induction by a wide variety of stress conditions. In mammals, TOR is a negative regulator of autophagy, and AMPK acts to activate autophagy both upstream of TOR, by inhibiting its activity, and in a parallel pathway. Inhibition of Arabidopsis TOR leads to activation of autophagy; inhibition of SnRK1 did not block this activation. Furthermore, an increase in SnRK1 activity was unable to induce autophagy when TOR was also activated. The results presented here demonstrate that SnRK1 acts upstream of TOR in the activation of autophagy in Arabidopsis.« less

Sm protein methylation is dispensable for snRNP assembly in Drosophila melanogaster.

PubMed

Gonsalvez, Graydon B; Praveen, Kavita; Hicks, Amanda J; Tian, Liping; Matera, A Gregory

2008-05-01

Sm proteins form stable ribonucleoprotein (RNP) complexes with small nuclear (sn)RNAs and are core components of the eukaryotic spliceosome. In vivo, the assembly of Sm proteins onto snRNAs requires the survival motor neurons (SMN) complex. Several reports have shown that SMN protein binds with high affinity to symmetric dimethylarginine (sDMA) residues present on the C-terminal tails of SmB, SmD1, and SmD3. This post-translational modification is thought to play a crucial role in snRNP assembly. In human cells, two distinct protein arginine methyltransferases (PRMT5 and PRMT7) are required for snRNP biogenesis. However, in Drosophila, loss of Dart5 (the fruit fly PRMT5 ortholog) has little effect on snRNP assembly, and homozygous mutants are completely viable. To resolve these apparent differences, we examined this topic in detail and found that Drosophila Sm proteins are also methylated by two methyltransferases, Dart5/PRMT5 and Dart7/PRMT7. Unlike dart5, we found that dart7 is an essential gene. However, the lethality associated with loss of Dart7 protein is apparently unrelated to defects in snRNP assembly. To conclusively test the requirement for sDMA modification of Sm proteins in Drosophila snRNP assembly, we constructed a fly strain that exclusively expresses an isoform of SmD1 that cannot be sDMA modified. Interestingly, these flies were viable, and snRNP assays revealed no defects in comparison to wild type. In contrast, dart5 mutants displayed a strong synthetic lethal phenotype in the presence of a hypomorphic Smn mutation. We therefore conclude that dart5 is required for viability when SMN is limiting.

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

Moraes, Paulo E.L., E-mail: pauloeduardo.leitedemoraes@gmail.com; Contieri, Rodrigo J., E-mail: contieri@fem.unicamp.br; Lopes, Eder S.N., E-mail: ederlopes@fem.unicamp.br

Ti and Ti alloys are widely used in restorative surgery because of their good biocompatibility, enhanced mechanical behavior and high corrosion resistance in physiological media. The corrosion resistance of Ti-based materials is due to the spontaneous formation of the TiO{sub 2} oxide film on their surface, which exhibits elevated stability in biological fluids. Ti–Nb alloys, depending on the composition and the processing routes to which the alloys are subjected, have high mechanical strength combined with low elastic modulus. The addition of Sn to Ti–Nb alloys allows the phase transformations to be controlled, particularly the precipitation of ω phase. The aimmore » of this study is to discuss the microstructure, mechanical properties and corrosion behavior of cast Ti–Nb alloys to which Sn has been added. Samples were centrifugally cast in a copper mold, and the microstructure was characterized using optical microscopy, scanning electron microscopy and X-ray diffractometry. Mechanical behavior evaluation was performed using Berkovich nanoindentation, Vickers hardness and compression tests. The corrosion behavior was evaluated in Ringer's solution at room temperature using electrochemical techniques. The results obtained suggested that the physical, mechanical and chemical behaviors of the Ti–Nb–Sn alloys are directly dependent on the Sn content. - Graphical abstract: Effects of Sn addition to the Ti–30Nb alloy on the elastic modulus. - Highlights: • Sn addition causes reduction of the ω phase precipitation. • Minimum Vickers hardness and elastic modulus occurred for 6 wt.% Sn content. • Addition of 6 wt.% Sn resulted in maximum ductility and minimum compression strength. • All Ti–30Nb–XSn (X = 0, 2, 4, 6, 8 and 10%) alloys are passive in Ringer's solution. • Highest corrosion resistance was observed for 6 wt.% Sn content.« less

Cellular monotectic model solidification

NASA Technical Reports Server (NTRS)

Kaukler, William F.

1987-01-01

Succinonitrile (sn) was purified to a superior level using a fractional recrystallization method. The melting point of the best twice recrystallized sn was not raised by following with double distillation. This was tested using differential scanning calorimetry. The peak shape on melting also proved that double distillation after double recrystallization did not improve the quality. Stability and phase diagrams for succinonitrile and glycerol are presented.

Buffer layer enhanced stability of sodium-ion storage

NASA Astrophysics Data System (ADS)

Wang, Xusheng; Yang, Zhanhai; Wang, Chao; Chen, Dong; Li, Rui; Zhang, Xinxiang; Chen, Jitao; Xue, Mianqi

2017-11-01

Se-Se buffer layers are introduced into tin sequences as SnSe2 single crystal to enhance the cycling stability for long-term sodium-ion storage by blazing a trail of self-defence strategy to structural pulverization especially at high current density. Specifically, under half-cell test, the SnSe2 electrodes could yield a high discharge capacity of 345 mAh g-1 after 300 cycles at 1 A g-1 and a high discharge capacity of 300 mAh g-1 after 2100 cycles at 5 A g-1 with stable coulombic efficiency and no capacity fading. Even with the ultrafast sodium-ion storage at 10 A g-1, the cycling stability still makes a positive response and a high discharge capacity of 221 mAh g-1 is demonstrated after 2700 cycles without capacity fading. The full-cell test for the SnSe2 electrodes also demonstrates the superior cycling stability. The flexible and tough Se-Se buffer layers are favourable to accommodate the sodium-ion intercalation process, and the autogenous Na2Se layers could confine the structural pulverization of further sodiated tin sequences by the slip along the Na2Se-NaxSn interfaces.

Laboratory Scoping Tests Of Decontamination Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

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

Taylor-Pashow, Kathryn M.; Nash, Charles A.; Crawford, Charles L.

2014-01-21

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrificationmore » mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task seeks to examine the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also compatible with longterm tank storage and immobilization methods. For this new application, testing is needed to demonstrate acceptable treatment sorbents and precipitating agents and measure decontamination factors for additional radionuclides in this unique waste stream. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet and will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. One of the radionuclides that is volatile and expected to be in high concentration in this LAW Off-Gas Condensate stream is Technetium-99 ( 99Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are also expected to be in appreciable concentration in the LAW Off-Gas Condensate are 129I, 90Sr, 137Cs, and {sup 241}Am. This report discusses results of preliminary radionuclide decontamination testing of the simulant. Testing examined use of Monosodium Titanate (MST) to remove 90Sr and actinides, inorganic reducing agents for 99Tc, and zeolites for 137Cs. Test results indicate that excellent removal of 99Tc was achieved using Sn(II)Cl 2 as a reductant, coupled with sorption onto hydroxyapatite, even in the presence of air and at room temperature. This process was very effective at neutral pH, with a Decontamination Factor (DF) >577 in two hours. It was less effective at alkaline pH. Conversely, removal of the cesium was more effective at alkaline pH, with a DF of 17.9. As anticipated, ammonium ion probably interfered with the Ionsiv®a IE-95 zeolite uptake of 137Cs. Although this DF of 137Cs was moderate, additional testing is expected to identify more effective conditions. Similarly, Monosodium Titanate (MST) was more effective at alkaline pH at removing Sr, Pu, and U, with a DF of 319, 11.6, and 10.5, respectively, within 24 hours. Actually, the Ionsiv® IE-95, which was targeting removal of Cs, was also moderately effective for Sr, and highly effective for Pu and U at alkaline pH. The only deleterious effect observed was that the chromium co-precipitates with the {sup 99}Tc during the SnCl 2 reduction. This effect was anticipated, and would have to be considered when managing disposition paths of this stream. Results of this separation testing indicate that sorption/precipitation was a viable concept and has the potential to decontaminate the stream. All radionuclides were at least partially removed by one or more of the materials tested. Based on the results, a possible treatment scenario could involve the use of a reductive precipitation agent (SnCl 2) and sorbent at neutral pH to remove the Tc, followed by pH adjustment and the addition of zeolite (Ionsiv® IE-95) to remove the Cs, Sr, and actinides. Addition of MST to remove Sr and actinides may not be needed. Since this was an initial phase of testing, additional tasks to improve separation methods were expected to be identified. Primarily, further testing is needed to identify the conditions for the decontamination process. Once these conditions are established, follow-on tasks likely include evaluation and testing of applicable solid-liquid separation technologies, slurry rheology measurements, composition variability testing and evaluations, corrosion and erosion testing, slurry storage and immobilization investigations, and decontaminated LAW Off-Gas Condensate evaporation and solidification.« less

Chemical vapor deposited carbon nanotubes for aqueous H2-Cl2 fuel cells.

PubMed

Suryavanshi, U B; Bhosale, C H

2010-06-01

Carbon nanotubes having large surface area is an interesting material to develop H2-Cl2 fuel cell electrodes. The attempts were made to deposit carbon nanotubes on porous substrates by chemical vapour deposition. Turpentine oil (C10H16) was used as a precursor, decomposed at 1100 degrees C reactor temperature. Nickel, platinum, tin, Ni-Pt, Ni-Sn, Pt-Sn, Ni-Pt-Sn catalysts were used to grow carbon nanotubes. Nickel was deposited with electrodeposition, platinum with sputter coater and tin with vacuum deposition technique. The developed electrodes were characterized by XRD, SEM, TEM, FTIR, and resistivity by van-der Pauw method. Carbon nanotubes have been formed for 0.25 N nickel deposited for 45 and 60 min; 0.5 N, 0.75 N and 1 N nickel deposited for 15 to 60 min, at the interval of 15. Ni-Pt, Ni-Sn, Pt-Sn and Ni-Pt-Sn activated carbon also shows the well grown CNTs. Aqueous H2-Cl2 fuel cell performance was tested with these grown carbon nanotubes. 40% KCl with 1067 mohm(-1) cm(-1) conductivity was used as electrolyte. Linear sweep voltametry shows reduction potential for hydrogen gas. Chronoamperometry results show better half cell performance for nickel, deposited with 1 N, 45 min deposition time period; and combination of Ni-Pt-Sn with 140, and 110-100 mA/cm2 stable current density respectively.

Toxicity of binary chemical munition destruction products: methylphosphonic acid, methylphosphinic acid, 2-diisopropylaminoethanol, DF neutralent, and QL neutralent.

PubMed

Watson, Rebecca E; Hafez, Ahmed M; Kremsky, Jonathan N; Bizzigotti, George O

2007-01-01

This paper reports the toxicity and environmental impact of neutralents produced from the hydrolysis of binary chemical agent precursor chemicals DF (methylphosphonic difluoride) and QL (2-[bis(1-methylethyl)amino]ethyl ethyl methylphosphonite). Following a literature review of the neutralent mixtures and constituents, basic toxicity tests were conducted to fill data gaps, including acute oral and dermal median lethal dose assays, the Ames mutagenicity test, and ecotoxicity tests. For methylphosphonic acid (MPA), a major constituent of DF neutralent, the acute oral LD(50) in the Sprague-Dawley rat was measured at 1888 mg/kg, and the Ames test using typical tester strains of Salmonella typhimurium and Escherichia coli was negative. The 48-h LC(50) values for pH-adjusted DF neutralent with Daphnia magna and Cyprinodon variegatus were > 2500 mg/L and 1593 mg/L, respectively. The acute oral LD(50) values in the rat for QL neutralent constituents methylphosphinic acid (MP) and 2-diisopropylaminoethanol (KB) were both determined to be 940 mg/kg, and the Ames test was negative for both. Good Laboratory Practice (GLP)-compliant ecotoxicity tests for MP and KB gave 48-h D. magna EC(50) values of 6.8 mg/L and 83 mg/L, respectively. GLP-compliant 96-h C. variegatus assays on MP and KB gave LC(50) values of 73 and 252 mg/L, respectively, and NOEC values of 22 and 108 mg/L. QL neutralent LD(50) values for acute oral and dermal toxicity tests were both > 5000 mg/kg, and the 48-h LD(50) values for D. magna and C. variegatus were 249 and 2500 mg/L, respectively. Using these data, the overall toxicity of the neutralents was assessed.

Effectiveness of a BHV-1/BEFV bivalent vaccine against bovine herpesvirus type 1 infection in cattle.

PubMed

Chung, Yao-Chi; Shen, Hsiu-Yen; Cheng, Li-Ting; Liu, Shyh-Shyan; Chu, Chun-Yen

2016-12-01

Bovine herpesvirus type 1 (BHV-1) causes acute febrile respiratory diseases (infectious bovine rhinotracheitis, IBR), decreased milk production, weight loss and abortion. Bovine ephemeral fever virus (BEFV) causes acute febrile respiratory disease, with pulmonary emphysema and pulmonary edema as the main signs. These viruses infect domesticated herds and lead to significant economic losses. In our previous study, an inactivated BHV-1 and BEFV bivalent vaccine was formulated with water-in-oil-in-water adjuvant, and vaccine efficacy was evaluated in guinea pigs. In this study, we evaluated the efficacy of the bivalent vaccine in cattle. Results showed that immunized cattle had a significantly higher level of total anti-BHV-1 antibody response (S/P ratio of 12.7) than the control group (S/P ratio of 0.07) 32weeks post-vaccination. The immunized group also showed higher neutralizing antibody levels against BHV-1 (SN=2 3.8 ) and BEFV (SN=2 4.6 ) than the control group (SN<2) 4 to 32weeks post-vaccination (p<0.05). In a BHV-1 challenge experiment, immunized cattle showed low virus shedding (10 1.2 TCID 50 /mL) and a significant reduction in pathological lesion scores (p<0.01). In conclusion, the BHV-1+BEFV+w/o/w vaccine not only improved long-term antibody immune response but also significantly reduced clinical signs in a BHV-1 challenge experiment. Our approach may be feasible for developing an effective vaccine against bovine herpesvirus type 1 and bovine ephemeral fever virus. Copyright © 2016 Elsevier Ltd. All rights reserved.

Designing lead-free and stable perovskite materials for photovoltaic applications

NASA Astrophysics Data System (ADS)

Sun, Yiyang; Zhang, Shengbai

A critical barrier for large-scale deployment of the current perovskite solar materials is the use of Pb to achieve high power conversion efficiency. While this appears to be a technical issue, there are more fundamental reasons behind. The current research has mainly focused on the replacement of Pb by other elements, in particular, Sn. However, in halide perovskites (i.e., I-II-VII3 composition), Sn is in its less stable 2 + state. The formation of more stable 4 + centers in the Sn(II)-based materials under ambient conditions makes the device efficiency very low. Worse, there might be no other elements across the Periodic Table that can replace Pb while maintaining the desirable properties, such as band gap. Out-of-the-box ideas are therefore called for to stimulate the research in this field. In this talk, two approaches are proposed based on state-of-the-art first-principles calculations. Through a screening of chalcogenide perovskite materials, CaTiS3, BaZrS3, CaZrSe3, and CaHfSe3 have been predicted to have suitable band gaps for making solar cells. Among these materials, BaZrS3 have been synthesized experimentally. Another proposed approach is to introduce dual anions (i.e., splitting the anion sites) that allow the composition to satisfy charge neutrality, while replacing Pb by more environmentally benign elements. One of the candidate materials is CH3NH3BiSI2, which is predicted to have band gap around 1.4 eV and high optical absorption.

Potential Fluctuations and Localization Effects in CZTS Single Crystals, as Revealed by Optical Spectroscopy

NASA Astrophysics Data System (ADS)

Bleuse, Joël; Ducroquet, Frédérique; Mariette, Henri

2018-03-01

Reports on Cu_2 ZnSn(S_x Se_{1-x} )_4 (CZTSSe) solar cell devices all show an open-circuit voltage lower than expected, especially when compared to CuIn_x Ga_{1-x} (S,Se)_2 devices, which reduces their power efficiency and delays their development. A high concentration of intrinsic defects in CZTSSe, and their stabilization through neutral complex formation, which induces some local fluctuations, are at the origin of local energy shifts in the conduction and valence band edges. The implied band tail in Cu_2 ZnSnS_4 is studied in this work by combining three types of optical spectroscopy data: emission spectra compared to photoluminescence excitation spectroscopy, emission spectra as a function of excitation power, and time-resolved photoluminescence spectra. All these data converge to show that both the bandgap and the band tail of localized states just below are dependent on the degree of order/disorder in the Cu/Zn cation sublattice of the quaternary structure: in the more ordered structures, the bandgap increases by about 50 meV, and the energy range of the band tail is decreased from about 110 to 70 meV.

Employing overlayers to improve the performance of Cu 2BaSnS 4 thin film based photoelectrochemical water reduction devices

DOE PAGES

Ge, Jie; Roland, Paul J.; Koirala, Prakash; ...

2017-01-19

Earth-abundant copper-barium-thiostannate Cu 2BaSnS 4 (CBTS)-based thin films have recently been reported to exhibit the optoelectronic and defect properties suitable as absorbers for photoelectrochemical (PEC) water splitting and the top cell of tandem photovoltaic solar cells. However, the photocurrents of CBTS-based PEC devices are still much lower than the theoretical value, partially due to ineffective charge collection at CBTS/water interface and instability of CBTS in electrolytes. Here, we report on overcoming these issues by employing overlayer engineering. We find that CdS/ZnO/TiO 2 overlayers can significant-ly improve the PEC performance, achieving saturated cathodic photocurrents up to 7.8 mA cm -2 atmore » the potential of -0.10 V versus reversible hydrogen electrode (RHE) in a neutral electrolyte solution, which is much higher than the best bare CBTS film attaining a photocurrent of 4.8 mA cm -2 at the potential of -0.2 V versus RHE. Finally, our results suggest a viable approach for improving the performance of CBTS-based PEC cells.« less

Resonance-mode electrochemical impedance measurements of silicon dioxide supported lipid bilayer formation and ion channel mediated charge transport.

PubMed

Lundgren, Anders; Hedlund, Julia; Andersson, Olof; Brändén, Magnus; Kunze, Angelika; Elwing, Hans; Höök, Fredrik

2011-10-15

A single-chip electrochemical method based on impedance measurements in resonance mode has been employed to study lipid monolayer and bilayer formation on hydrophobic alkanethiolate and SiO(2) substrates, respectively. The processes were monitored by temporally resolving changes in interfacial capacitance and resistance, revealing information about the rate of formation, coverage, and defect density (quality) of the layers at saturation. The resonance-based impedance measurements were shown to reveal significant differences in the layer formation process of bilayers made from (i) positively charged lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-ethylphosphocholine (POEPC), (ii) neutral lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) on SiO(2), and (iii) monolayers made from POEPC on hydrophobic alkanethiolate substrates. The observed responses were represented with an equivalent circuit, suggesting that the differences primarily originate from the presence of a conductive aqueous layer between the lipid bilayers and the SiO(2). In addition, by adding the ion channel gramicidin D to bilayers supported on SiO(2), channel-mediated charge transport could be measured with high sensitivity (resolution around 1 pA). © 2011 American Chemical Society

Clinical comparison of plaque inhibition effects of a novel stabilized stannous fluoride dentifrice and a chlorhexidine digluconate dentifrice using digital plaque imaging.

PubMed

Bellamy, P G; Boulding, A; Farmer, S; Day, T N; Mussett, A J; Barker, M L

2011-01-01

To compare the plaque inhibition efficacy of a novel 0.454% stannous fluoride (SnF2) test dentifrice with sodium hexametaphosphate and stannous chloride to a chlorhexidine digluconate (0.05%), aluminium lactate (0.8%), and aluminium fluoride marketed control dentifrice (Lacalut Aktiv or AlF3/Chx). This was a randomized, two-treatment, two-period, double-blind crossover study that compared the SnF2 test dentifrice to the AlF3/Chx control dentifrice. Each of the two treatment periods lasted for 17 consecutive days of product use, during which subjects were required to brush twice per day with their assigned dentifrice using a standard manual toothbrush (Oral-B P35 Indicator). The two periods of the crossover were separated by a four-day washout period. Plaque levels on the facial anterior tooth surfaces were evaluated and averaged among three assessment days at the end of each treatment period using digital plaque imaging analysis (DPIA). The evening prior to assessments, subjects only brushed lingual surfaces. Assessment time points were carried out in the morning following no morning brushing (A.M. pre-brush), following 40 seconds of brushing with the assigned dentifrice (A.M. post-brush), and in the afternoon (P.M.). The DPIA captured images were used to calculate and analyze visible plaque coverage. Twenty-eight subjects were randomized and completed the study. At each assessment time point, the SnF2 test dentifrice demonstrated a statistically significant lower plaque level compared to the AlF3/Chx dentifrice: A.M. mean pre-brush 15.9% lower, p < 0.05; A.M. mean post-brush 22.2% lower, p < 0.05; P.M. mean 24.3% lower, p < 0.005. Compared to the AlF3/Chx control dentifrice, the novel SnF2 test dentifrice significantly inhibited plaque regrowth overnight and during the day. Immediately after brushing there was also significantly less plaque coverage with the SnF2 test dentifrice.

Flip-chip assembly and reliability using gold/tin solder bumps

NASA Astrophysics Data System (ADS)

Oppermann, Hermann; Hutter, Matthias; Klein, Matthias; Reichl, Herbert

2004-09-01

Au/Sn solder bumps are commonly used for flip chip assembly of optoelectronic and RF devices. They allow a fluxless assembly which is required to avoid contamination at optical interfaces. Flip chip assembly experiments were carried out using as plated Au/Sn bumps without prior bump reflow. An RF and reliability test vehicles comprise a GaAs chip which was flip chip soldered on a silicon substrate. Temperature cycling tests with and without underfiller were performed and the results are presented. The different failure modes for underfilled and non-underfilled samples were discussed and compared. Additional reliability tests were performed with flip chip bonding by gold thermocompression for comparison. The test results and the failure modes are discussed in detail.

Thermoelectric generator testing and RTG degradation mechanisms evaluation. Progress report No. 33

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

Lockwood, A.; Stapfer, G.

1979-12-01

The n-type selenide legs after 10,600 hours continue to show agreement with the 3M Co. published data. In the ingradient testing after 11,378 hours the n-legs show comparable performance to the reported 3M data. The new design p-type legs were placed on test. The remaining MHW generator on test Q1-A has accumulated 19,567 hours and performance remains stable. Three 18 couple modules S/N-1, 2, and 3 previously tested at RCA were received for JPL test and evaluation. S/N-1 has 1700 hours testing at JPL with results indistinguishable from those at the end of RCA testing in 1977. The performances ofmore » LES 8/9 generators are following DEGRA predications after 31,824 hours. The performance of the Voyager 1 and 2 RTGs is reported after 19,577 hours and 20,122 hours of operation, respectively.« less

In vitro induction of micronuclei by monofunctional methanesulphonic acid esters: possible role of alkylation mechanisms.

PubMed

Eder, Erwin; Kütt, Wolfgang; Deininger, Christoph

2006-12-01

Six monofunctional alkylating methanesulphonates of widely varying structures were investigated in the in vitro micronucleus assay with Syrian hamster embryo fibroblast cells. The results were compared with the alkylating activities measured in the 4-(nitrobenzyl)pyridine test (NBP-test) and the N-methyl mercaptoimidazole (MMI-test) as measures for S(N)2 reactivity as well as in the triflouoroacetic acid (TFA) solvolysis and the hydrolysis reaction as measures for S(N)1 reactivity in order to provide insights into the role of alkylation mechanisms on induction of micronuclei. Moreover we compared the results of micronucleus assay with those of the Ames tests in strain TA 100 and TA1535 and with those of the SOS chromotest with the strains PQ37, PQ243, PM21 and GC 4798. The potency of methanesulphonates to induce micronuclei depended only to a certain degree, on the total alkylating activity (S(N)1 and S(N)2 reactivity). An inverse, significant correlation between the Ames test and the micronucleus assay was observed and an inverse correlation between the micronucleus assay and the SOS chromotest with the different strains. The results indicate that the primary mechanism leading to induction of micronuclei is not O-alkylation in DNA as it is the case in the Ames test with the hisG46 strains TA1535 and TA100 and not N-alkylation as with the SOS chromotest. There is evidence that protein alkylation, e.g. in the spindle apparatus in mitosis is decisive for induction of micronuclei by alkylating compounds. The structurally voluminous methanesulphonates 2-phenyl ethyl methanesulphonate and 1-phenyl-2-propyl methanesulphonate show a clear higher micronuclei inducing potency than the other tested though the bulky methanesulphonates possess a lower total alkylating activity than the others. This effect can be explained by a higher disturbance during mitosis after alkylation of the spindle apparatus with the structurally more bulky methanesulphonates.

Effect of ghrelin on the motor deficit caused by the ablation of nigrostriatal dopaminergic cells or the inhibition of striatal dopamine receptors.

PubMed

Suda, Yukari; Kuzumaki, Naoko; Narita, Michiko; Hamada, Yusuke; Shibasaki, Masahiro; Tanaka, Kenichi; Tamura, Hideki; Kawamura, Takashi; Kondo, Takashige; Yamanaka, Akihiro; Narita, Minoru

2018-02-19

Ghrelin plays roles in a wide range of central functions by activating the growth hormone secretagogue receptor (GHSR). This receptor has recently been found in the substantia nigra (SN) to control dopamine (DA)-related physiological functions. The dysregulation of DA neurons in the SN pars compacta (SNc) and the consequent depletion of striatal DA are known to underlie the motor deficits observed in Parkinson's disease (PD). In the present study, we further investigated the role of the SN-ghrelin system in motor function under the stereotaxic injection of AAV-CMV-FLEX-diphtheria toxin A (DTA) into the SN of dopamine transporter (DAT)-Cre (DAT SN ::DTA) mice to expunge DA neurons of the SNc. First, we confirmed the dominant expression of GHSR1a, which is a functional GHSR, in tyrosine hydroxylase (TH)-positive DA neurons in the SNc of control mice. In DAT SN ::DTA mice, we clearly observed motor dysfunction using several behavioral tests. An immunohistochemical study revealed a dramatic loss of TH-positive DA neurons in the SNc and DAT-labeled axon terminals in the striatum, and an absence of mRNAs for TH and DAT in the SN of DAT SN ::DTA mice. The mRNA level of GHSR1a was drastically decreased in the SN of these mice. In normal mice, we also found the mRNA expression of GHSR1a within GABAergic neurons in the SN pars reticulata (SNr). Under these conditions, a single injection of ghrelin into the SN failed to improve the motor deficits caused by ablation of the nigrostriatal DA network using DAT SN ::DTA mice, whereas intra-SN injection of ghrelin suppressed the motor dysfunction caused by the administration of haloperidol, which is associated with the transient inhibition of DA transmission. These findings suggest that phasic activation of the SNc-ghrelin system could improve the dysregulation of nigrostriatal DA transmission related to the initial stage of PD, but not the motor deficits under the depletion of nigrostriatal DA. Although GHSRs are found in non-DA cells of the SNr, GHSRs on DA neurons in the SNc may play a crucial role in motor function. Copyright © 2018. Published by Elsevier Inc.

The effect of Sn addition on phase stability and phase evolution during aging heat treatment in Ti–Mo alloys employed as biomaterials

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

Mello, Mariana G. de, E-mail: marianagm@fem.unicamp.br; Salvador, Camilo F., E-mail: csalvador@fem.unicamp.br; Cremasco, Alessandra, E-mail: alessandra@fem.unicamp.br

Increases in life expectancy and improvements in necessary healthcare attach great importance to the development of biomaterials. Ti alloys containing β stabilizing elements are often used as biomaterials due to their high specific strength, high corrosion resistance, unusual biocompatibility and low elastic moduli, which benefit bone tissues close to an implant. This study deals with phase stability in β Ti–Mo–Sn alloys processed under different conditions and was performed according to the following steps: a study of the effect of Sn content (a) on phase stability in Ti–Mo alloys, (b) on the suppression of α″ and ω phase precipitation; (c) onmore » α-phase precipitation during aging heat treatments and (d) on mechanical properties, including the elastic modulus, as measured using tensile tests and acoustic techniques. The alloys were prepared by arc melting under a controlled atmosphere followed by homogenization heat treatment and hot rolling. Optical microscopy, scanning and transmission electron microscopy, X-ray diffraction and differential scanning calorimetry were employed for characterization purposes. Samples were also submitted to solution treatment above the β transus temperature and aging heat treatments under a controlled atmosphere. The results suggest that Sn suppresses the formation of the ω and α″ phases in Ti–Mo system. - Highlights: • Sn addition to Ti alloys decreases elastic modulus by suppressing ω phase precipitation. • Sn addition decreases the temperature of martensite decomposition. • Sn addition decreases the temperature of α phase precipitation and β transus. • Mechanical strength decreases with increasing Sn content.« less

Steering Charge Kinetics of Tin Niobate Photocatalysts: Key Roles of Phase Structure and Electronic Structure

NASA Astrophysics Data System (ADS)

Huang, Shushu; Wang, Chunyan; Sun, Hao; Wang, Xiaojing; Su, Yiguo

2018-05-01

Tin niobate photocatalysts with the phase structures of froodite (SnNb2O6) and pyrochlore (Sn2Nb2O7) were obtained by a facile solvothermal method in order to explore the impact of phase structure and electronic structure on the charge kinetics and photocatalytic performance. By employing tin niobate as a model compound, the effects of phase structure over electronic structure, photocatalytic activity toward methyl orange solution and hydrogen evolution were systematically investigated. It is found that the variation of phase structure from SnNb2O6 to Sn2Nb2O7 accompanied with modulation of particle size and band edge potentials that has great consequences on photocatalytic performance. In combination with the electrochemical impedance spectroscopy (EIS), transient photocurrent responses, transient absorption spectroscopy (TAS), and the analysis of the charge-carrier dynamics suggested that variation of electronic structure has great impacts on the charge separation and transfer rate of tin niobate photocatalysts and the subsequent photocatalytic performance. Moreover, the results of the X-ray photoelectron spectroscopy (XPS) indicated that the existent of Sn4+ species in Sn2Nb2O7 could result in a decrease in photocatalytic activity. Photocatalytic test demonstrated that the SnNb2O6 (froodite) catalyst possesses a higher photocatalytic activity toward MO degradation and H2 evolution compared with the sample of Sn2Nb2O7 (pyrochlore). On the basis of spin resonance measurement and trapping experiment, it is expected that photogenerated holes, O2 -•, and OH• active species dominate the photodegradation of methyl orange.

Steering Charge Kinetics of Tin Niobate Photocatalysts: Key Roles of Phase Structure and Electronic Structure.

PubMed

Huang, Shushu; Wang, Chunyan; Sun, Hao; Wang, Xiaojing; Su, Yiguo

2018-05-23

Tin niobate photocatalysts with the phase structures of froodite (SnNb 2 O 6 ) and pyrochlore (Sn 2 Nb 2 O 7 ) were obtained by a facile solvothermal method in order to explore the impact of phase structure and electronic structure on the charge kinetics and photocatalytic performance. By employing tin niobate as a model compound, the effects of phase structure over electronic structure, photocatalytic activity toward methyl orange solution and hydrogen evolution were systematically investigated. It is found that the variation of phase structure from SnNb 2 O 6 to Sn 2 Nb 2 O 7 accompanied with modulation of particle size and band edge potentials that has great consequences on photocatalytic performance. In combination with the electrochemical impedance spectroscopy (EIS), transient photocurrent responses, transient absorption spectroscopy (TAS), and the analysis of the charge-carrier dynamics suggested that variation of electronic structure has great impacts on the charge separation and transfer rate of tin niobate photocatalysts and the subsequent photocatalytic performance. Moreover, the results of the X-ray photoelectron spectroscopy (XPS) indicated that the existent of Sn 4+ species in Sn 2 Nb 2 O 7 could result in a decrease in photocatalytic activity. Photocatalytic test demonstrated that the SnNb 2 O 6 (froodite) catalyst possesses a higher photocatalytic activity toward MO degradation and H 2 evolution compared with the sample of Sn 2 Nb 2 O 7 (pyrochlore). On the basis of spin resonance measurement and trapping experiment, it is expected that photogenerated holes, O 2 -• , and OH • active species dominate the photodegradation of methyl orange.

Adsorption and photocatalysis efficiency of magnetite quantum dots anchored tin dioxide nanofibers for removal of mutagenic compound: Toxicity evaluation and antibacterial activity.

PubMed

Fakhri, Ali; Naji, Mahsa; Nejad, Pedram Afshar

2017-08-01

The Magnetite Fe 3 O 4 quantum dots anchored SnO 2 nanofibers (Fe 3 O 4 QDs/SnO 2 NFs) have been synthesized using the facile one step hydrothermal method. The characteristic structure of synthesized Fe 3 O 4 QDs/SnO 2 NFs was analyzed using X-ray diffraction, Transmission electron Microscopy, Scanning electron microscopy, UV-vis diffuse reflectance, photoluminescence spectroscopy, and N 2 adsorption-desorption instrumental techniques. The crystallites size of Fe 3 O 4 QDs/SnO 2 NFs was 7.0nm. The average diameters of Fe 3 O 4 QDs/SnO 2 NFs were 7.25nm. BET surface area of Fe 3 O 4 QDs/SnO 2 NFs has been found 53.064m 2 /g. The activity of Fe 3 O 4 QDs/SnO 2 NFs samples were compared towards adsorption and degradation of mutagenic compound such as Ethyl methanesulfonate (EMS). The Fe 3 O 4 QDs/SnO 2 NFs demonstrates 93.85% and 56.85% photo degradation and adsorption activity towards 10ppm EMS solution in 30 and 40min, respectively. Fe 3 O 4 QDs/SnO 2 NFs shows maximum removal of EMS at pH5. Additionally, cytotoxicity test showed that the newly developed catalyst has low cytotoxic effects on three kinds of human cells. The antibacterial activity evaluation against two bacterials, including Staphylococcus aureus (ATCC 43300), and Pseudomonas aeruginosa (ATCC 27853) was considered. It was found that the MIC values for the antibacterial assay in the presence of Fe 3 O 4 QDs/SnO 2 NFs were around 0.38mM with 83.4, and 85.5% inhibition for the S. aureus, and P. aeruginosa bacterial strains, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Milatuzumab-SN-38 conjugates for the treatment of CD74+ cancers.

PubMed

Govindan, Serengulam V; Cardillo, Thomas M; Sharkey, Robert M; Tat, Fatma; Gold, David V; Goldenberg, David M

2013-06-01

CD74 is an attractive target for antibody-drug conjugates (ADC), because it internalizes and recycles after antibody binding. CD74 mostly is associated with hematologic tumors but is expressed also in solid cancers. Therefore, ADCs of the humanized anti-CD74 antibody, milatuzumab, were examined for the therapy of CD74-expressing solid tumors. Milatuzumab-doxorubicin and two milatuzumab-SN-38 conjugates with cleavable linkers, differing in their stability in serum and how they release SN-38 in the lysosome, were prepared. CD74 expression was determined by flow cytometry and immunohistology. In vitro cytotoxicity and in vivo therapeutic studies were conducted in the human cancer cell lines A-375 (melanoma), HuH-7 and Hep-G2 (hepatoma), Capan-1 (pancreatic), NCI-N87 (gastric), and Raji Burkitt lymphoma. The milatuzumab-SN-38 ADC was compared with SN-38 ADCs prepared with anti-Trop-2 and anti-CEACAM6 antibodies in xenografts expressing their target antigens. Milatuzumab-doxorubicin was most effective in the lymphoma model, whereas in A-375 and Capan-1 solid tumors, only milatuzumab-SN-38 showed a therapeutic benefit. Despite much lower surface expression of CD74 than Trop-2 or CEACAM6, milatuzumab-SN-38 had similar efficacy in Capan-1 as anti-Trop-2-SN-38, but in NCI-N87, anti-CEACAM6 and anti-Trop-2 conjugates were superior. Studies in two hepatoma lines at a single dose level showed significant benefit over saline controls but not against an irrelevant immunoglobulin G conjugate. CD74 is a suitable target for ADCs in some solid tumor xenografts, with efficacy largely influenced by uniformity of CD74 expression and with SN-38 conjugates providing the best therapeutic responses; SN-38 conjugates were preferable in solid cancers, whereas doxorubicin ADC was better in lymphoma tested. ©2013 AACR

Progress in the Long $${\\rm Nb}_{3}{\\rm Sn}$$ Quadrupole R&D by LARP

DOE PAGES

Ambrosio, G.; Andreev, N.; Anerella, M.; ...

2011-11-14

After the successful test of the first long Nb 3Sn quadrupole (LQS01) the US LHC Accelerator Research Program (LARP, a collaboration of BNL, FNAL, LBNL and SLAC) is assessing training memory, reproducibility, and other accelerator quality features of long Nb 3Sn quadrupole magnets. LQS01b (a reassembly of LQS01 with more uniform and higher pre-stress) was subjected to a full thermal cycle and reached the previous plateau of 222 T/m at 4.5 K in two quenches. A new set of four coils, made of the same type of conductor used in LQS01 (RRP 54/61 by Oxford Superconducting Technology), was assembled inmore » the LQS01 structure and tested at 4.5 K and lower temperatures. The new magnet (LQS02) reached the target gradient (200 T/m) only at 2.6 K and lower temperatures, at intermediate ramp rates. The preliminary test analysis, here reported, showed a higher instability in the limiting coil than in the other coils of LQS01 and LQS02.« less

Shear Recovery Accuracy in Weak-Lensing Analysis with the Elliptical Gauss-Laguerre Method

NASA Astrophysics Data System (ADS)

Nakajima, Reiko; Bernstein, Gary

2007-04-01

We implement the elliptical Gauss-Laguerre (EGL) galaxy-shape measurement method proposed by Bernstein & Jarvis and quantify the shear recovery accuracy in weak-lensing analysis. This method uses a deconvolution fitting scheme to remove the effects of the point-spread function (PSF). The test simulates >107 noisy galaxy images convolved with anisotropic PSFs and attempts to recover an input shear. The tests are designed to be immune to statistical (random) distributions of shapes, selection biases, and crowding, in order to test more rigorously the effects of detection significance (signal-to-noise ratio [S/N]), PSF, and galaxy resolution. The systematic error in shear recovery is divided into two classes, calibration (multiplicative) and additive, with the latter arising from PSF anisotropy. At S/N > 50, the deconvolution method measures the galaxy shape and input shear to ~1% multiplicative accuracy and suppresses >99% of the PSF anisotropy. These systematic errors increase to ~4% for the worst conditions, with poorly resolved galaxies at S/N simeq 20. The EGL weak-lensing analysis has the best demonstrated accuracy to date, sufficient for the next generation of weak-lensing surveys.

Transmissible gastroenteritis virus: plaques and a plaque neutralization test.

PubMed Central

Thomas, F C; Dulac, G C

1976-01-01

A plaquing system and plaque neutralization test in porcine thyroid cells were used to study different transmissible gastroenteritis isolates and hemagglutinating encephalomyelitis virus. Among transmissible gastroenteritis virus isolates, plaque size varied considerably and mixed size ranges sometimes occurred. The most recently isolated viruses produced smaller plaques than the laboratory viruses or hemagglutinating encephalomyelitis virus. All transmissible gastroenteritis virus isolates reacted in the plaque neutralization test with a transmissible gastroenteritis virus antiserum which showed no activity against hemagglutinating encephalomyelitis virus. Plaque neutralization results both from experimentally infected pigs and following a field outbreak demonstrated the reliability of this test and its greater sensitivity than the conventional tube test. Images Fig. 1. PMID:187296

Robust model comparison disfavors power law cosmology

NASA Astrophysics Data System (ADS)

Shafer, Daniel L.

2015-05-01

Late-time power law expansion has been proposed as an alternative to the standard cosmological model and shown to be consistent with some low-redshift data. We test power law expansion against the standard flat Λ CDM cosmology using goodness-of-fit and model comparison criteria. We consider type Ia supernova (SN Ia) data from two current compilations (JLA and Union2.1) along with a current set of baryon acoustic oscillation (BAO) measurements that includes the high-redshift Lyman-α forest measurements from BOSS quasars. We find that neither power law expansion nor Λ CDM is strongly preferred over the other when the SN Ia and BAO data are analyzed separately but that power law expansion is strongly disfavored by the combination. We treat the Rh=c t cosmology (a constant rate of expansion) separately and find that it is conclusively disfavored by all combinations of data that include SN Ia observations and a poor overall fit when systematic errors in the SN Ia measurements are ignored, despite a recent claim to the contrary. We discuss this claim and some concerns regarding hidden model dependence in the SN Ia data.

Nanostructured tin oxide films: Physical synthesis, characterization, and gas sensing properties.

PubMed

Ingole, S M; Navale, S T; Navale, Y H; Bandgar, D K; Stadler, F J; Mane, R S; Ramgir, N S; Gupta, S K; Aswal, D K; Patil, V B

2017-05-01

Nanostructured tin oxide (SnO 2 ) films are synthesized using physical method i.e. thermal evaporation and are further characterized with X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy measurement techniques for confirming its structure and morphology. The chemiresistive properties of SnO 2 films are studied towards different oxidizing and reducing gases where these films have demonstrated considerable selectivity towards oxidizing nitrogen dioxide (NO 2 ) gas with a maximum response of 403% to 100ppm @200°C, and fast response and recovery times of 4s and 210s, respectively, than other test gases. In addition, SnO 2 films are enabling to detect as low as 1ppm NO 2 gas concentration @200°C with 23% response enhancement. Chemiresistive performances of SnO 2 films are carried out in the range of 1-100ppm and reported. Finally, plausible adsorption and desorption reaction mechanism of NO 2 gas molecules with SnO 2 film surface has been thoroughly discussed by means of an impedance spectroscopy analysis. Copyright © 2017 Elsevier Inc. All rights reserved.

Alcohol Use and HIV Risk Within Social Networks of MSM Sex Workers in the Dominican Republic.

PubMed

Tan, Diane; Holloway, Ian W; Gildner, Jennifer; Jauregui, Juan C; Garcia Alvarez, Rafael; Guilamo-Ramos, Vincent

2017-11-01

To examine how alcohol-related HIV risk behaviors within MSM sex workers' social networks (SN) may be associated with individual risk behaviors, respondent-driven and venue-based sampling were used to collect demographic, behavioral and SN characteristics among MSM sex workers in Santo Domingo and Boca Chica (N = 220). The majority of participants reported problem drinking (71.0%) or alcohol use at their last sexual encounter (71.4%). Self-reported problem drinking was associated with SN characteristics (at least one member who recently got drunk aOR = 7.5, no religious/spiritual adviser aOR = 3.0, non-sexual network density aOR = 0.9), while self-reported alcohol use at last sex was associated with individual (drug use at last sex aOR = 4.4) and SN characteristics (at least one member with previous HIV/STI testing aOR = 4.7). Dominican MSM sex workers reported high alcohol use, which may increase their risk for HIV. A better understanding of SN factors associated with individual risk behaviors can help guide appropriate intervention development.

SnO2 quantum dots decorated on RGO: a superior sensitive, selective and reproducible performance for a H2 and LPG sensor.

PubMed

Mishra, R K; Upadhyay, S B; Kushwaha, Ajay; Kim, Tae-Hyung; Murali, G; Verma, Ranjana; Srivastava, Manish; Singh, Jay; Sahay, P P; Lee, Seung Hee

2015-07-28

We report the H2 and LPG gas sensing behavior of RGO/SnO2 QDs synthesized by a surfactant assisted hydrothermal method. The RGO/SnO2 QD based sensor shows a high response of ∼89.3% to H2 and ∼92.4% to LPG for 500 ppm test gas concentration at operating temperatures of 200 °C and 250 °C, respectively. Further, the RGO/SnO2 QD based sensor shows good selectivity for H2 and LPG in the presence of other interfering gases such as ammonia, chloroform, toluene, benzene, acetone, n-butylacetate, acetic acid and formic acid. We observed that the gas response to H2 is 29.8 times higher than that to acetic acid whereas the gas response to LPG is 17.8 times higher than that to formic acid. Long-term analyses have also been performed to demonstrate the reproducible nature of the RGO/SnO2 QD based sensor over passing time which shows excellent reproducibility.

Fluorescent light induces neurodegeneration in the rodent nigrostriatal system but near infrared LED light does not.

PubMed

Romeo, Stefania; Vitale, Flora; Viaggi, Cristina; di Marco, Stefano; Aloisi, Gabriella; Fasciani, Irene; Pardini, Carla; Pietrantoni, Ilaria; Di Paolo, Mattia; Riccitelli, Serena; Maccarone, Rita; Mattei, Claudia; Capannolo, Marta; Rossi, Mario; Capozzo, Annamaria; Corsini, Giovanni U; Scarnati, Eugenio; Lozzi, Luca; Vaglini, Francesca; Maggio, Roberto

2017-05-01

We investigated the effects of continuous artificial light exposure on the mouse substantia nigra (SN). A three month exposure of C57Bl/6J mice to white fluorescent light induced a 30% reduction in dopamine (DA) neurons in SN compared to controls, accompanied by a decrease of DA and its metabolites in the striatum. After six months of exposure, neurodegeneration progressed slightly, but the level of DA returned to the basal level, while the metabolites increased with respect to the control. Three month exposure to near infrared LED light (∼710nm) did not alter DA neurons in SN, nor did it decrease DA and its metabolites in the striatum. Furthermore mesencephalic cell viability, as tested by [ 3 H]DA uptake, did not change. Finally, we observed that 710nm LED light, locally conveyed in the rat SN, could modulate the firing activity of extracellular-recorded DA neurons. These data suggest that light can be detrimental or beneficial to DA neurons in SN, depending on the source and wavelength. Copyright © 2017 Elsevier B.V. All rights reserved.

Observation of Iron Specific Interaction with a Charge Neutral Phospholipid

NASA Astrophysics Data System (ADS)

Wang, Wenjie; Zhang, Honghu; Feng, Shuren; San Emeterio, Josue; Kuzmenko, Ivan; Nilsen-Hamilton, Marit; Mallapragada, Surya; Vaknin, David

2015-03-01

Using surface sensitive X-ray scattering and spectroscopic techniques we show that phosphatidyl choline (PC) head groups attract positively charged iron ions and complexes even at pH values that are lower than 3. DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) is a zwitterionic lipid typically used as a model system for cell membranes. Within a large pH range (3 -11), it carries a negative charge on the phosphate group and a positive charge on the quaternary ammonium cation, thus appears charge neutral. Further lowering the pH, i.e. adding a proton to the phosphate group, results in a positively charged headgroup. Surprisingly, we detect significant enrichment of iron at the interface of the DPPC monolayer and the aqueous subphase with the pH maintained at 3 or even lower. With a supposedly charge neutral or even positive surface, the observation of surface bound, charge positive iron ions or iron hydroxides is counter-intuitive and suggests iron-specific interaction with the phospholipid headgroup, which is not governed by electrostatic interaction. The effect of the integration of Mms6, a membrane protein that promotes the formation of magnetic nanocrystals, into the DPPC monolayer will also be discussed. Research supported by the U.S. Department of Energy under Contract No. DE-AC02-07CH11358 and DE-AC02-06CH11357.

Improved electron collisional line broadening for low-temperature ions and neutrals in plasma modeling

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

Johns, H. M.; Kilcrease, D. P.; Colgan, J.

In this study, electron collisional broadening of observed spectral lines depends on plasma electron temperature and density. Including this effect in models of measured spectra is necessary to determine plasma conditions; however, computational limits make accurate line broadening treatments difficult to implement in large-scale plasma modeling efforts. In this paper, we report on improvements to the treatment of electron collisional line broadening and illustrate this with calculations using the Los Alamos ATOMIC code. We implement the Dimitrijevic and Konjevic modified semi-empirical model Dimitrijevic and Konjevic (1986 Astron. and Astrophy. 163 297 and 1987 Astron. Astrophys. 172 345), which we amendmore » by employing oscillator strengths from Hartree–Fock calculations. This line broadening model applies to near-neutral plasmas with electron temperatures of Te ~ 1 eV and electron densities of N e ~10 17 cm -3. We evaluate the D.K.-inspired model against the previous hydrogenic approach in ATOMIC through comparison to NIST-rated measurements for selected neutral and singly-ionized Ca, O, Fe, and Sn lines using both fine-structure and configuration-averaged oscillator strengths. The new D.K.-inspired model is significantly more accurate than the previous hydrogenic model and we find the use of configuration-averaged oscillator strengths a good approximation for applications such as LIBS (laser induced breakdown spectroscopy), for which we demonstrate the use of the D.K.-inspired model.« less

Improved electron collisional line broadening for low-temperature ions and neutrals in plasma modeling

DOE PAGES

Johns, H. M.; Kilcrease, D. P.; Colgan, J.; ...

2015-09-29

In this study, electron collisional broadening of observed spectral lines depends on plasma electron temperature and density. Including this effect in models of measured spectra is necessary to determine plasma conditions; however, computational limits make accurate line broadening treatments difficult to implement in large-scale plasma modeling efforts. In this paper, we report on improvements to the treatment of electron collisional line broadening and illustrate this with calculations using the Los Alamos ATOMIC code. We implement the Dimitrijevic and Konjevic modified semi-empirical model Dimitrijevic and Konjevic (1986 Astron. and Astrophy. 163 297 and 1987 Astron. Astrophys. 172 345), which we amendmore » by employing oscillator strengths from Hartree–Fock calculations. This line broadening model applies to near-neutral plasmas with electron temperatures of Te ~ 1 eV and electron densities of N e ~10 17 cm -3. We evaluate the D.K.-inspired model against the previous hydrogenic approach in ATOMIC through comparison to NIST-rated measurements for selected neutral and singly-ionized Ca, O, Fe, and Sn lines using both fine-structure and configuration-averaged oscillator strengths. The new D.K.-inspired model is significantly more accurate than the previous hydrogenic model and we find the use of configuration-averaged oscillator strengths a good approximation for applications such as LIBS (laser induced breakdown spectroscopy), for which we demonstrate the use of the D.K.-inspired model.« less

Current Progress in Fabrication of a 14 Tesla Nb3Sn Dipole

NASA Astrophysics Data System (ADS)

Holik, Eddie, III; Benson, Christopher; Damborsky, Kyle; Diaczenko, Nick; Elliott, Tim; Garrison, Ray; Jaisle, Andrew; McInturff, Alfred; McIntyre, Peter; Sattarov, Dior

2012-03-01

The Accelerator Technology Laboratory at Texas A&M is fabricating a model dipole magnet, TAMU3, designed to operate at a 14 Tesla bore field. The dipole employs an advanced internal-tin Nb3Sn/Cu composite strand with enhanced current density. The coils must be processed through a heat treatment after winding, during which the Sn within the heterogeneous strands diffuse into the Cu/Nb matrix to form high-performance superconducting layers. Heat treatment of the first coil assembly revealed tin leakage from the Sn cores that was caused by omission of a pre-anneal step in the heat treatment. We are evaluating the electrical properties of the coil, the microstructure and short-sample superconducting performance of cut-off samples of current leads to determine the extent of damage to the performance of the windings. Results of those tests and plans for construction of TAMU3 will be presented.

Synergistic influence of Al, Ni, Bi and Sn addition to a zinc bath upon growth kinetics and the structure of coatings

NASA Astrophysics Data System (ADS)

Kania, H.; Liberski, P.

2012-05-01

In this article the authors have analysed the current knowledge about the influence of alloy additions used in galvanizing baths. The optimum concentration of Al, Ni, Bi and Sn addition has been established. Some tests have been conducted to determine the synergistic effect of the addition of AlNiBiSn to a zinc bath upon the structure and growth kinetics of coatings. The structure of the coatings obtained on steel with low silicon contents and on Sandelin steel as well as their chemical composition have been revealed. It has been established that the addition of AlNiBiSn helps to reduce excessive growth of coating on Sandelin steel. The chemical composition and the structure of the coating on Sandelin steel are similar to the chemical composition and structure obtained on steel with regular silicon contents.

Molten Salt Electrolytically Produced Carbon/Tin Nanomaterial as the Anode in a Lithium Ion Battery

NASA Astrophysics Data System (ADS)

Das Gupta, Rajshekar; Schwandt, Carsten; Fray, Derek J.

2017-03-01

A carbon/tin nanomaterial, consisting of predominantly Sn-filled carbon nanotubes and nanoparticles, is prepared by molten salt electrochemistry, using electrodes of graphite and an electrolyte of LiCl salt containing a small admixture of SnCl2. The C/Sn hybrid material generated is incorporated into the active anode material of a lithium ion battery and tested with regard to storage capacity and cycling behavior. The results demonstrate that the C/Sn material has favorable properties, in terms of energy density and in particular long-term stability, that exceed those of the individual components alone. The initial irreversible capacity of the material is somewhat larger than that of conventional battery graphite which is due to its unique nanostructure. Overall the results would indicate the suitability of this material for use in the anodes of lithium ion batteries with high rate capability.

Structure analysis for hole-nuclei close to 132Sn by a large-scale shell-model calculation

NASA Astrophysics Data System (ADS)

Wang, Han-Kui; Sun, Yang; Jin, Hua; Kaneko, Kazunari; Tazaki, Shigeru

2013-11-01

The structure of neutron-rich nuclei with a few holes in respect of the doubly magic nucleus 132Sn is investigated by means of large-scale shell-model calculations. For a considerably large model space, including orbitals allowing both neutron and proton core excitations, an effective interaction for the extended pairing-plus-quadrupole model with monopole corrections is tested through detailed comparison between the calculation and experimental data. By using the experimental energy of the core-excited 21/2+ level in 131In as a benchmark, monopole corrections are determined that describe the size of the neutron N=82 shell gap. The level spectra, up to 5 MeV of excitation in 131In, 131Sn, 130In, 130Cd, and 130Sn, are well described and clearly explained by couplings of single-hole orbitals and by core excitations.

Inorganic Photocatalytic Enhancement: Activated RhB Photodegradation by Surface Modification of SnO2 Nanocrystals with V2O5-like species

PubMed Central

Epifani, Mauro; Kaciulis, Saulius; Mezzi, Alessio; Altamura, Davide; Giannini, Cinzia; Díaz, Raül; Force, Carmen; Genç, Aziz; Arbiol, Jordi; Siciliano, Pietro; Comini, Elisabetta; Concina, Isabella

2017-01-01

SnO2 nanocrystals were prepared by precipitation in dodecylamine at 100 °C, then they were reacted with vanadium chloromethoxide in oleic acid at 250 °C. The resulting materials were heat-treated at various temperatures up to 650 °C for thermal stabilization, chemical purification and for studying the overall structural transformations. From the crossed use of various characterization techniques, it emerged that the as-prepared materials were constituted by cassiterite SnO2 nanocrystals with a surface modified by isolated V(IV) oxide species. After heat-treatment at 400 °C, the SnO2 nanocrystals were wrapped by layers composed of vanadium oxide (IV-V mixed oxidation state) and carbon residuals. After heating at 500 °C, only SnO2 cassiterite nanocrystals were obtained, with a mean size of 2.8 nm and wrapped by only V2O5-like species. The samples heat-treated at 500 °C were tested as RhB photodegradation catalysts. At 10−7 M concentration, all RhB was degraded within 1 h of reaction, at a much faster rate than all pure SnO2 materials reported until now. PMID:28300185

Electrodeposition of Sn-Ni Alloy Coatings for Water-Splitting Application from Alkaline Medium

NASA Astrophysics Data System (ADS)

Shetty, Sandhya; Hegde, A. Chitharanjan

2017-02-01

In this work, Sn-Ni alloy coatings were developed onto the surface of copper from a newly formulated electrolytic bath by a simple and cost-effective electrodeposition technique using gelatin as an additive. The electrocatalytic behavior of coatings deposited at different current densities (c.d.'s) for water-splitting applications, in terms of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), has been researched. The experimental results showed that the electrocatalytic activity of Sn-Ni coatings has a close relationship with its composition, surface morphology, and phase structure depending on the c.d. used, supported by scanning electron microscopy (SEM-EDX) and X-ray diffraction (XRD) analyses. Cyclic voltammetry and chronopotentiometry techniques have demonstrated that Sn-Ni alloy deposited at 4.0 A dm-2 (having 37.6 wt pct Ni) and 1.0 A dm-2 (having 19.6 wt pct Ni) exhibit, respectively, the highest electrocatalytic behavior for HER and OER in 1.0-M KOH solution. Sn-Ni alloy coatings were found to be stable under working conditions of electrolysis, confirmed by electrochemical corrosion tests. High electrocatalytic activity of Sn-Ni alloy coatings for both HER and OER is specific to their composition, surface morphology, and active surface area.

A study of Bi-Pb-Sn-Cd-Sb penta-alloys rapidly quenched from melt

NASA Astrophysics Data System (ADS)

Kamal, M.; El-Bediwi, A. B.

2004-11-01

Optical microscopy, X-ray diffractometry, the double bridge method, the Vickers microhardness testing and dynamic resonance techniques have been used to investigate structure, electrical resistivity, hardness, internal friction and elastic modulus of quenched Bi-Pb-Sn-Cd-Sb penta-alloys. The properties of these penta-alloys are greatly affected by rapid quenching. The intermetallic compound chi(Pb-Bi) or Bi3Pb7 is obtained after rapid quenching using the melt-spinning technique, and this is in agreement with reports by other authors [Marshall, T.J., Mott, G. T. and Grieverson, M. H. (1975). Br. J. Radiol., 48, 924, Kamal, M., El-Bediwi, A. B. and Karman, M. B. (1998). Structure, mechanical properties and electrical resistivity of rapidly solidified Pb-Sn-Cd and Pb-Bi-Sn-Cd alloys. J. Mater. Sci.: Mater. Electron., 9, 425, Borromee-Gautier, C., Giessen, B. C. and Grrant, N. J. (1968). J. Chem. Phys., 48,1905, Moon, K.-W., Boettinger, W. J., Kanner, U. R., Handwerker, C. A. and Lee, D.-J. (2001). The effect of Pb contamination on the solidification behavior of Sn-Bi solders. J. Electron. Mater, 30, 45.]. The quenched Bi43.5Pb44.5Cd5Sn2Sb5 alloy has important properties for safety devices in fire detection and extinguishing systems.

Developmental and genetic toxicity of stannous chloride in mouse dams and fetuses.

PubMed

El-Makawy, Aida I; Girgis, Shenouda M; Khalil, Wagdy K B

2008-12-08

Humans are exposed to stannous chloride (SnCl2) present in packaged food, soft drinks, biocides, dentifrices, etc. Health effects in children exposed to tin and tin compounds have not been investigated yet. Therefore, we evaluated the possible teratogenic and genotoxic effects of SnCl2 in pregnant female mice and their fetuses. Teratogenic effects including morphological malformation of the fetus and its skeleton were observed. Exposures to environmental stressors including toxic chemicals that have the potential of modulating the immune system can often be linked to ecologically relevant endpoints, such as reduced resistance to disease. Therefore, the semi-quantitative reverse-transcription PCR (RT-PCR) assay was used to evaluate the expression of immune-response genes in the liver of SnCl2-treated dams and their fetuses. Bone-marrow cells of dams and fetuses were investigated for the presence of aberrant chromosomes. Three oral doses of SnCl2 (2, 10 and 20 mg/kg bw) were tested. The results of the teratological study show that SnCl2 induced a significant decrease in the number of living fetuses and a significant increase in the number of post-implantation losses. The high dose of SnCl2 induced complete post-implantation loss. Furthermore, SnCl2 caused reduction in the ossification of the fetal skeleton. The RT-PCR assay showed that the immune-response genes GARP and SIMP were not expressed in the liver of dams and fetuses in the controls or in the group treated with SnCl2 at 2 mg/kg bw. However, the expression of these genes was up-regulated in the groups treated with the other doses of SnCl2. Regarding the chromosome analysis, SnCl2 induced a dose-dependent increase in the frequency of individual and total chromosomal aberrations (P

Scientific Research Institute of Aviation Materials (Selected Articles).

DTIC Science & Technology

1979-01-22

7.50/0 Al addit ionally alloyed vith Zo ’o Sn. As the tests shoved (Pig . 1). after heating alloy s which do not cont a in silicon f~ r an additiona l...10 k ;/a i’ 500—700 ° (Pig. 2). The resu lts of long—term tests shoved that alloy s with 3.So/o Sn (without silicon ) ha ve a high level of heat-resist...I~~ _ _ _ _ _ _ The addit ion of 0.8o/o Cu to the alloy does not a f fe :t its phase composition and microstruct ure , but further

What is Driving the H I Velocity Dispersion?

NASA Astrophysics Data System (ADS)

Tamburro, D.; Rix, H.-W.; Leroy, A. K.; Mac Low, M.-M.; Walter, F.; Kennicutt, R. C.; Brinks, E.; de Blok, W. J. G.

2009-05-01

We explore what dominant physical mechanism sets the kinetic energy contained in neutral, atomic (H I) gas. Both supernova (SN) explosions and magnetorotational instability (MRI) have been proposed to drive turbulence in gas disks and we compare the H I line widths predicted from turbulence driven by these mechanisms to direct observations in 11 disk galaxies. We use high-quality maps of the H I mass surface density and line width, obtained by The H I Nearby Galaxy Survey. We show that all sample galaxies exhibit a systematic radial decline in the H I line width, which appears to be a generic property of H I disks and also implies a radial decline in kinetic energy density of H I. At a galactocentric radius of r 25—often comparable to the extent of significant star formation—there is a characteristic value of the H I velocity dispersion of 10 ± 2 km s-1. Inside this radius, galaxies show H I line widths well above the thermal value (corresponding to ~8 km s-1) expected from a warm H I component, implying that turbulence drivers must be responsible for maintaining this line width. Therefore, we compare maps of H I kinetic energy to maps of the star formation rate (SFR)—a proxy for the SN rate—and to predictions for energy generated by MRI. We find a positive correlation between kinetic energy of H I and SFR; this correlation also holds at fixed Σ_{H I}, as expected if SNe were driving turbulence. For a given turbulence dissipation timescale, we can estimate the energy input required to maintain the observed kinetic energy. The SN rate implied by the observed recent SFR is sufficient to maintain the observed velocity dispersion, if the SN feedback efficiency is at least epsilonSN sime 0.1 × (107 yr/τ D ), assuming τ D sime 107 yr for the turbulence dissipation timescale. Beyond r 25, this efficiency would have to increase to unrealistic values, epsilon gsim 1, suggesting that mechanical energy input from young stellar populations does not supply most kinetic energy in outer disks. On the other hand, both thermal broadening and turbulence driven by MRI can plausibly produce the velocity dispersions and kinetic energies that we observe in this regime (gsimr 25).

High degree of correlation between Ebola virus BSL-4 neutralization assays and pseudotyped VSV BSL-2 fluorescence reduction neutralization test.

PubMed

Konduru, Krishnamurthy; Shurtleff, Amy C; Bavari, Sina; Kaplan, Gerardo

2018-04-01

Ebola virus (EBOV), classified as a category A agent by the CDC and NIH, requires BSL-4 containment and induces high morbidity and mortality in humans. The 2013-2015 epidemic in West Africa underscored the urgent need to develop vaccines and therapeutics to prevent and treat EBOV disease. Neutralization assays are needed to evaluate the efficacy of EBOV vaccines and antibody therapies. Pseudotyped viruses based on nonpathogenic or attenuated vectors reduce the risks involved in the evaluation of neutralizing antibodies against highly pathogenic viruses. Selectable markers, fluorescent proteins, and luciferase have been introduced into pseudotyped viruses for detection and quantitation purposes. The current study describes the development of a BSL-2 fluorescence reduction neutralization test (FRNT) using a recombinant vesicular stomatitis virus (VSV) in which the VSV-G envelope gene was replaced with the EBOV glycoprotein (GP) and green fluorescent protein (GFP) genes (rVSV-EBOVgp-GFP). Cells infected with rVSV-EBOVgp-GFP express GFP. Anti-GP neutralizing monoclonal and polyclonal antibodies blocked rVSV-EBOVgp-GFP infection preventing or reducing GFP fluorescence. The high degree of correlation between the EBOV BSL-2 FRNT and the BSL-4 plaque reduction neutralization test (PRNT), the accepted standard of EBOV neutralization tests, supports the use of the EBOV BSL-2 FRNT to evaluate neutralizing antibodies in clinical trials. Published by Elsevier B.V.

Changes in fatty acid composition in plant tissues expressing a mammalian delta9 desaturase.

PubMed

Moon, H; Hazebroek, J; Hildebrand, D F

2000-05-01

Plant tissues expressing a mammalian stearoyl-CoA delta9 desaturase were reported to accumulate delta9 hexadecenoic acid (16:1), normally very minor in most plant tissues. The transgenic plants were thoroughly analyzed for alterations of individual lipids in different subcellular sites. Western blot analysis indicated that the animal desaturase was targeted to the microsomes. The delta9 16:1 was incorporated into both the sn-1 and sn-2 positions of all the major membrane lipids tested, indicating that the endoplasmic reticulum acyltransferases do not exclude unsaturated C16 fatty acids from the sn-2 position. In addition to increases in monounsaturated and decreases in saturated fatty acids, accumulation of 16:1 was accompanied by a reduction in 18:3 in all the lipids tested except phosphatidylglycerol, and increases in 18:2 in phospholipids. Total C16 fatty acid content in the galactolipids of the transgenics was significantly higher than that in the control, but those in the phospholipids were unchanged. In transgenics, delta11 18:1 was detected in the sn-1 position of the lipids tested except phosphatidylinositol and phosphatidylserine. Introduction of the animal desaturase, controlled by a seed-specific phaseolin promoter, into soybean somatic embryo resulted in a significant reduction in saturated fatty acids. Such effects were greater in cotyledons than hypocotyl-radicles. This study demonstrated that the animal desaturase can be used to decrease the levels of saturated fatty acids in a crop plant.

Effect of Solder-Joint Geometry on the Low-Cycle Fatigue Behavior of Sn- xAg-0.7Cu

NASA Astrophysics Data System (ADS)

Lee, Hwa-Teng; Huang, Kuo-Chen

2016-12-01

Low-cycle fatigue tests of Sn-Ag-Cu (SAC) Pb-free solder joints under fixed displacement were performed to evaluate the influence of Ag content (0-3 wt.%) and solder-joint geometry (barrel and hourglass types) on solder-joint fatigue behavior and reliability. The solder joints were composed of fine particles of Ag3Sn and Cu6Sn5, which aggregated as an eutectic constituent at grain boundaries of the primary β-Sn phase and formed a dense network structure. A decrease in the Ag content resulted in coarsening of the β-Sn and eutectic phases, which, in turn, decreased the strength of the joint and caused earlier failure. Solder joints in the hourglass form exhibited better fatigue performance with longer life than barrel-type joints. The sharp contact angle formed between the solder and the Cu substrate by the barrel-type joints concentrated stress, which compromised fatigue reliability. The addition of Ag to the solder, however, enhanced fatigue performance because of strengthening caused by Ag3Sn formation. The cracks of the barrel-type SAC solder joints originated mostly at the contact corner and propagated along the interfacial layer between the interfacial intermetallic compound (IMC) and solder matrix. Hourglass-type solder joints, however, demonstrated both crack initiation and propagation in the solder matrix (solder mode). The addition of 1.5-2.0 wt.% Ag to SAC solder appears to enhance the fatigue performance of solder joints while maintaining sufficient strength.

Enzyme-linked immunosorbent assays for detection of equine antibodies specific to Sarcocystis neurona surface antigens.

PubMed

Hoane, Jessica S; Morrow, Jennifer K; Saville, William J; Dubey, J P; Granstrom, David E; Howe, Daniel K

2005-09-01

Sarcocystis neurona is the primary causative agent of equine protozoal myeloencephalitis (EPM), a common neurologic disease of horses in the Americas. We have developed a set of enzyme-linked immunosorbent assays (ELISAs) based on the four major surface antigens of S. neurona (SnSAGs) to analyze the equine antibody response to S. neurona. The SnSAG ELISAs were optimized and standardized with a sample set of 36 equine sera that had been characterized by Western blotting against total S. neurona parasite antigen, the current gold standard for S. neurona serology. The recombinant SnSAG2 (rSnSAG2) ELISA showed the highest sensitivity and specificity at 95.5% and 92.9%, respectively. In contrast, only 68.2% sensitivity and 71.4% specificity were achieved with the rSnSAG1 ELISA, indicating that this antigen may not be a reliable serological marker for analyzing antibodies against S. neurona in horses. Importantly, the ELISA antigens did not show cross-reactivity with antisera to Sarcocystis fayeri or Neospora hughesi, two other equine parasites. The accuracy and reliability exhibited by the SnSAG ELISAs suggest that these assays will be valuable tools for examining the equine immune response against S. neurona infection, which may help in understanding the pathobiology of this accidental parasite-host interaction. Moreover, with modification and further investigation, the SnSAG ELISAs have potential for use as immunodiagnostic tests to aid in the identification of horses affected by EPM.

Enzyme-Linked Immunosorbent Assays for Detection of Equine Antibodies Specific to Sarcocystis neurona Surface Antigens†

PubMed Central

Hoane, Jessica S.; Morrow, Jennifer K.; Saville, William J.; Dubey, J. P.; Granstrom, David E.; Howe, Daniel K.

2005-01-01

Sarcocystis neurona is the primary causative agent of equine protozoal myeloencephalitis (EPM), a common neurologic disease of horses in the Americas. We have developed a set of enzyme-linked immunosorbent assays (ELISAs) based on the four major surface antigens of S. neurona (SnSAGs) to analyze the equine antibody response to S. neurona. The SnSAG ELISAs were optimized and standardized with a sample set of 36 equine sera that had been characterized by Western blotting against total S. neurona parasite antigen, the current gold standard for S. neurona serology. The recombinant SnSAG2 (rSnSAG2) ELISA showed the highest sensitivity and specificity at 95.5% and 92.9%, respectively. In contrast, only 68.2% sensitivity and 71.4% specificity were achieved with the rSnSAG1 ELISA, indicating that this antigen may not be a reliable serological marker for analyzing antibodies against S. neurona in horses. Importantly, the ELISA antigens did not show cross-reactivity with antisera to Sarcocystis fayeri or Neospora hughesi, two other equine parasites. The accuracy and reliability exhibited by the SnSAG ELISAs suggest that these assays will be valuable tools for examining the equine immune response against S. neurona infection, which may help in understanding the pathobiology of this accidental parasite-host interaction. Moreover, with modification and further investigation, the SnSAG ELISAs have potential for use as immunodiagnostic tests to aid in the identification of horses affected by EPM. PMID:16148170

Solvent-Free Synthesis of Uniform MOF Shell-Derived Carbon Confined SnO2 /Co Nanocubes for Highly Reversible Lithium Storage.

PubMed

He, Qiu; Liu, Jinshuai; Li, Zhaohuai; Li, Qi; Xu, Lin; Zhang, Baoxuan; Meng, Jiashen; Wu, Yuzhu; Mai, Liqiang

2017-10-01

Tin dioxide (SnO 2 ) has attracted much attention in lithium-ion batteries (LIBs) due to its abundant source, low cost, and high theoretical capacity. However, the large volume variation, irreversible conversion reaction limit its further practical application in next-generation LIBs. Here, a novel solvent-free approach to construct uniform metal-organic framework (MOF) shell-derived carbon confined SnO 2 /Co (SnO 2 /Co@C) nanocubes via a two-step heat treatment is developed. In particular, MOF-coated CoSnO 3 hollow nanocubes are for the first time synthesized as the intermediate product by an extremely simple thermal solid-phase reaction, which is further developed as a general strategy to successfully obtain other uniform MOF-coated metal oxides. The as-synthesized SnO 2 /Co@C nanocubes, when tested as LIB anodes, exhibit a highly reversible discharge capacity of 800 mAh g -1 after 100 cycles at 200 mA g -1 and excellent cycling stability with a retained capacity of 400 mAh g -1 after 1800 cycles at 5 A g -1 . The experimental analyses demonstrate that these excellent performances are mainly ascribed to the delicate structure and a synergistic effect between Co and SnO 2 . This facile synthetic approach will greatly contribute to the development of functional metal oxide-based and MOF-assisted nanostructures in many frontier applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Yttrium Addition on Microstructure and Mechanical Properties of AZ80-2Sn Magnesium Alloys

NASA Astrophysics Data System (ADS)

Xue, Hansong; Yang, Gang; Li, Di; Xing, Zhihui; Pan, Fusheng

2015-12-01

The effects of Y on microstructure and mechanical properties of as-cast AZ80-2Sn magnesium alloys were investigated by optical microscopy, scanning electron microscopy and X-ray diffraction. Y addition not only changes the as-cast microstructure but also influences the mechanical properties of AZ80-2Sn alloy. Unmodified AZ80-2Sn alloys under casting state show that Mg17Al12 eutectic phase is semicontinuous and reticulated shape and distributes mainly at grain boundaries. Moreover, there are numerous Mg2Sn precipitate particles dispersing in Mg17Al12 eutectic phases. Y addition to as-cast AZ80-2Sn alloys has an important influence on the precipitation phase. But there has no obvious effect on grain refinement with Y addition. The results show that the AZ80-2Sn alloys with variable Y contents all contain Al2Y phase. By adding Y, the amount of Mg17Al12 is decreased and the dimension of that is reduced. Mg17Al12 eutectic phase turns to discontinuous, and the more disperse phases occur with the increase of Y content. The tensile tests indicate that a minor addition of Y can contribute to the formation of the dispersed small polygonal Al2Y particles and the improvement in the room-temperature strength. However, excessive Y addition leads to the coarsening of Al2Y phases, and thus results in the decline of strength and ductility.

Encouraging expressions affect the brain and alter visual attention.

PubMed

Martín-Loeches, Manuel; Sel, Alejandra; Casado, Pilar; Jiménez, Laura; Castellanos, Luis

2009-06-17

Very often, encouraging or discouraging expressions are used in competitive contexts, such as sports practice, aiming at provoking an emotional reaction on the listener and, consequently, an effect on subsequent cognition and/or performance. However, the actual efficiency of these expressions has not been tested scientifically. To fill this gap, we studied the effects of encouraging, discouraging, and neutral expressions on event-related brain electrical activity during a visual selective attention task in which targets were determined by location, shape, and color. Although the expressions preceded the attentional task, both encouraging and discouraging messages elicited a similar long-lasting brain emotional response present during the visuospatial task. In addition, encouraging expressions were able to alter the customary working pattern of the visual attention system for shape selection in the attended location, increasing the P1 and the SP modulations while simultaneously fading away the SN. This was interpreted as an enhancement of the attentional processes for shape in the attended location after an encouraging expression. It can be stated, therefore, that encouraging expressions, as those used in sport practice, as well as in many other contexts and situations, do seem to be efficient in exerting emotional reactions and measurable effects on cognition.

A effective DNA vaccine against diverse genotype J infectious hematopoietic necrosis virus strains prevalent in China

USGS Publications Warehouse

Xu, Liming; Zhao, Jingzhuang; Liu, Miao; Kurath, Gael; Ren, Guangming; LaPatra, Scott E.; Yin, Jiasheng; Liu, Hongbai; Feng, Jian; Lu, Tongyan

2017-01-01

Infectious hematopoietic necrosis virus (IHNV) is the most important pathogen threatening the aquaculture of salmonid fish in China. In this study, a DNA vaccine, designated pIHNch-G, was constructed with the glycoprotein (G) gene of a Chinese IHNV isolate SD-12 (also called Sn1203) of genotype J. The minimal dose of vaccine required, the expression of the Mx-1 gene in the muscle (vaccine delivery site) and anterior kidney, and the titers of the neutralizing antibodies produced were used to evaluate the vaccine efficacy. To assess the potential utility of the vaccine in controlling IHNV throughout China, the cross protective efficacy of the vaccine was determined by challenging fish with a broad range of IHNV strains from different geographic locations in China. A single 100 ng dose of the vaccine conferred almost full protection to rainbow trout fry (3 g) against waterborne or intraperitoneal injection challenge with IHNV strain SD-12 as early as 4 days post-vaccination (d.p.v.), and significant protection was still observed at 180 d.p.v. Intragenogroup challenges showed that the DNA vaccine provided similar protection to the fish against all the Chinese IHNV isolates tested, suggesting that the vaccine can be widely used in China. Mx-1 gene expression was significantly upregulated in the muscle tissue (vaccine delivery site) and anterior kidney in the vaccinated rainbow trout at both 4 and 7 d.p.v. Similar levels of neutralizing antibodies were determined with each of the Chinese IHNV strains at 60 and 180 d.p.v. This DNA vaccine should play an important role in the control of IHN in China.

When does Subliminal Affective Image Priming Influence the Ability of Schizophrenic Patients to Perceive Face Emotions?

PubMed Central

Vaina, Lucia M.; Rana, Kunjan D.; Cotos, Ionela; Li-Yang, Chen; Huang, Melissa A.; Podea, Delia

2014-01-01

Background Deficits in face emotion perception are among the most pervasive aspects of schizophrenia impairments which strongly affects interpersonal communication and social skills. Material/Methods Schizophrenic patients (PSZ) and healthy control subjects (HCS) performed 2 psychophysical tasks. One, the SAFFIMAP test, was designed to determine the impact of subliminally presented affective or neutral images on the accuracy of face-expression (angry or neutral) perception. In the second test, FEP, subjects saw pictures of face-expression and were asked to rate them as angry, happy, or neutral. The following clinical scales were used to determine the acute symptoms in PSZ: Positive and Negative Syndrome (PANSS), Young Mania Rating (YMRS), Hamilton Depression (HAM-D), and Hamilton Anxiety (HAM-A). Results On the SAFFIMAP test, different from the HCS group, the PSZ group tended to categorize the neutral expression of test faces as angry and their response to the test-face expression was not influenced by the affective content of the primes. In PSZ, the PANSS-positive score was significantly correlated with correct perception of angry faces for aggressive or pleasant primes. YMRS scores were strongly correlated with PSZ’s tendency to recognize angry face expressions when the prime was a pleasant or a neutral image. The HAM-D score was positively correlated with categorizing the test-faces as neutral, regardless of the affective content of the prime or of the test-face expression (angry or neutral). Conclusions Despite its exploratory nature, this study provides the first evidence that conscious perception and categorization of facial emotions (neutral or angry) in PSZ is directly affected by their positive or negative symptoms of the disease as defined by their individual scores on the clinical diagnostic scales. PMID:25537115

When does subliminal affective image priming influence the ability of schizophrenic patients to perceive face emotions?

PubMed

Vaina, Lucia Maria; Rana, Kunjan D; Cotos, Ionela; Li-Yang, Chen; Huang, Melissa A; Podea, Delia

2014-12-24

Deficits in face emotion perception are among the most pervasive aspects of schizophrenia impairments which strongly affects interpersonal communication and social skills. Schizophrenic patients (PSZ) and healthy control subjects (HCS) performed 2 psychophysical tasks. One, the SAFFIMAP test, was designed to determine the impact of subliminally presented affective or neutral images on the accuracy of face-expression (angry or neutral) perception. In the second test, FEP, subjects saw pictures of face-expression and were asked to rate them as angry, happy, or neutral. The following clinical scales were used to determine the acute symptoms in PSZ: Positive and Negative Syndrome (PANSS), Young Mania Rating (YMRS), Hamilton Depression (HAM-D), and Hamilton Anxiety (HAM-A). On the SAFFIMAP test, different from the HCS group, the PSZ group tended to categorize the neutral expression of test faces as angry and their response to the test-face expression was not influenced by the affective content of the primes. In PSZ, the PANSS-positive score was significantly correlated with correct perception of angry faces for aggressive or pleasant primes. YMRS scores were strongly correlated with PSZ's tendency to recognize angry face expressions when the prime was a pleasant or a neutral image. The HAM-D score was positively correlated with categorizing the test-faces as neutral, regardless of the affective content of the prime or of the test-face expression (angry or neutral). Despite its exploratory nature, this study provides the first evidence that conscious perception and categorization of facial emotions (neutral or angry) in PSZ is directly affected by their positive or negative symptoms of the disease as defined by their individual scores on the clinical diagnostic scales.

Neutral-red reaction is related to virulence and cell wall methyl-branched lipids in Mycobacterium tuberculosis.

PubMed

Cardona, P-J; Soto, C Y; Martín, C; Giquel, B; Agustí, G; Andreu, Núria; Guirado, E; Sirakova, T; Kolattukudy, P; Julián, E; Luquin, M

2006-01-01

Searching for virulence marking tests for Mycobacterium tuberculosis, Dubos and Middlebrook reported in 1948 that in an alkaline aqueous solution of neutral-red, the cells of the virulent H37Rv M. tuberculosis strain fixed the dye and became red in color, whereas the cells of the avirulent H37Ra M. tuberculosis strain remained unstained. In the 1950 and 1960s, fresh isolates of M. tuberculosis were tested for this neutral-red cytochemical reaction and it was reported that they were neutral-red positive, whereas other mycobacteria of diverse environmental origins that were non-pathogenic for guinea pigs were neutral-red negative. However, neutral-red has not really been proven to be a virulence marker. To test if virulence is in fact correlated to neutral-red, we studied a clinical isolate of M. tuberculosis that was originally neutral-red positive but, after more than 1 year passing through culture mediums, turned neutral-red negative. We found that, in comparison to the original neutral-red positive strain, this neutral-red negative variant was attenuated in two murine models of experimental tuberculosis. Lipid analysis showed that this neutral-red negative natural mutant lost the capacity to synthesize pthiocerol dimycocerosates, a cell wall methyl-branched lipid that has been related to virulence in M. tuberculosis. We also studied the neutral-red of different gene-targeted M. tuberculosis mutants unable to produce pthiocerol dimycocerosates or other cell wall methyl-branched lipids such as sulfolipids, and polyacyltrehaloses. We found a negative neutral-red reaction in mutants that were deficient in more than one type of methyl-branched lipids. We conclude that neutral-red is indeed a marker of virulence and it indicates important perturbations in the external surface of M. tuberculosis cells.

Effect of heterovalent substitutions in yttrium chromite on the hyperfine interactions of {sup 119}Sn{sup 4+} studied by Mössbauer spectroscopy

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

Fabritchnyi, Pavel B., E-mail: pf_1404@yahoo.fr; Afanasov, Mikhail I.; Mezhuev, Evgeny M.

2016-03-15

In order to develop the {sup 119}Sn Mössbauer spectroscopic probe technique to study magnetically ordered materials, three Ca-substituted yttrium chromites, i.e. Y{sub 0.9}Ca{sub 0.1}CrO{sub 3}, Y{sub 0.9}Ca{sub 0.1}Cr{sub 0.9}Ti{sub 0.1}O{sub 3} and Y{sub 0.8}Ca{sub 0.2}Cr{sub 0.8}Ti{sub 0.2}O{sub 3}, doped with 0.3 atom-% Sn{sup 4+}, were for the first time investigated. {sup 119}Sn Mössbauer spectra, recorded at 4.2 K, have allowed, through analysis of the magnetic hyperfine field values, probed by {sup 119}Sn nuclei, to gain insight into the local magnetically active surrounding of different Sn{sup 4+} ions. In all of these compounds, partial segregation of Sn{sup 4+} ions is revealed.more » In the case of Y{sub 0.9}Ca{sub 0.1}CrO{sub 3}, neither highly oxidized Cr{sup 4+} nor Cr{sup 6+} species, expected to compensate for the Ca{sup 2+} positive charge deficit, is found in the vicinity of the {sup 119}Sn{sup 4+} probe. In the case of both studied Ti-containing chromites, {sup 119}Sn Mössbauer spectra have provided the original indirect evidence for the statistical distribution of Cr{sup 3+} and Ti{sup 4+} ions over the octahedral sites and permitted characterization of the occurring associates of Sn{sup 4+}. - Graphical abstract: Two kinds of Sn{sup 4+} associates allowing {sup 119}Sn Mössbauer spectra of tin-doped Y{sub 0.9}Ca{sub 0.1}Cr{sub 0.9}Ti{sub 0.1}O{sub 3} and Y{sub 0.8}Ca{sub 0.2}Cr{sub 0.8}Ti{sub 0.2}O{sub 3} to be accounted for. - Highlights: • {sup 119}Sn probe is tested as a source of information on the B-sublattice of AF perovskites. • Neither Cr{sup 3+} nor Cr{sup 6+} is detected nearby {sup 119}Sn{sup 4+} ions in Y{sub 0.9}Ca{sub 0.1}CrO{sub 3}. • Cr{sup 3+} and Ti{sup 4+} are found to be randomly distributed in Y{sub 1−x}Ca{sub x}Cr{sub 1−x}Ti{sub x}O{sub 3} (x=0.1 or 0.2). • Sn{sup 4+} dopant segregations are revealed in all of the studied materials.« less

Advanced Gas Turbine (AGT) powertrain system development for automotive applications

NASA Technical Reports Server (NTRS)

1984-01-01

Rotor dynamic instability investigations were conducted. Forward ball bearing hydraulic mount configurations were tested with little effect. Trial assembly of S/N 002 ceramic engine was initiated. Impeller design activities were completed on the straight line element (SLE) blade definition to address near-net-shape powder metal die forging. Performance characteristics of the Baseline Test 2A impeller were closely preserved. The modified blading design has been released for tooling procurement. Developmental testing of the diffusion flame combustor (DFC) for initial use in the S/N 002 2100 F ceramic structures engine was completed. A natural gas slave preheater was designed and fabricated. Preliminary regenerator static seal rig testing showed a significant reduction in leakage and sensitivity to stack height. Ceramic screening tests were completed and two complete sets of ceramic static structures were qualified for engine testing. Efforts on rotor dynamics development to resolve subsynchronous motion were continued.

An Infrared Search for Extinguished Supernovae in Starburst Galaxies

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

Grossan, B.; Spillar, E.; Tripp, R.

1999-08-01

IR and radio-band observations of heavily extinguished regions in starburst galaxies suggest a high supernova (SN) rate associated with such regions. Optically measured SN rates may therefore underestimate the total SN rate by factors of up to 10, as a result of the very high extinction ({ital A}{sub {ital B}}thinsp{approximately}thinsp10{endash}20 mag) to core-collapse SNe in starburst regions. The IR/radio SN rates come from a variety of indirect means, however, which suffer from model dependence and other problems. We describe a direct measurement of the SN rate from a regular patrol of starburst galaxies done with {ital K}{prime}-band imaging to minimizemore » the effects of extinction. A collection of {ital K}{prime}-band measurements of core-collapse SNe near maximum light is presented. Such measurements (excluding 1987A) are not well reported in the literature. Results of a preliminary {ital K}{prime}-band search, using the MIRC camera at the Wyoming Infrared Observatory and an improved search strategy using the new ORCA optics, are described. A monthly patrol of a sample of {ital IRAS} bright (mostly starburst) galaxies within 25 Mpc should yield 1{endash}6 SNe yr{sup {minus}1}, corresponding to the range of estimated SN rates. Our initial MIRC search with low resolution (2&arcsec;2 pixels) failed to find extinguished SNe in the {ital IRAS} galaxies, limiting the SN rate outside the nucleus (at greater than 15{double_prime} radius) to less than 3.8 far-IR SN rate units (SNe per century per 10{sup 10} {ital L}{sub {circle_dot}} measured at 60 and 100 {mu}m, or FIRSRU) at 90{percent} confidence. The MIRC camera had insufficient resolution to search nuclear starburst regions, where starburst and SN activity is concentrated; therefore, we were unable to rigorously test the hypothesis of high SN rates in heavily obscured star-forming regions. We conclude that high-resolution nuclear SN searches in starburst galaxies with small fields are more productive than low-resolution, large-field searches, even for our sample of large (often several arcminutes) galaxies. With our ORCA high-resolution optics, we could limit the total SN rate to less than 1.3 FIRSRU at 90{percent} confidence in 3 years of observations, lower than most estimates. {copyright} {ital {copyright} 1999.} {ital The American Astronomical Society}« less

Emotional facial expressions differentially influence predictions and performance for face recognition.

PubMed

Nomi, Jason S; Rhodes, Matthew G; Cleary, Anne M

2013-01-01

This study examined how participants' predictions of future memory performance are influenced by emotional facial expressions. Participants made judgements of learning (JOLs) predicting the likelihood that they would correctly identify a face displaying a happy, angry, or neutral emotional expression in a future two-alternative forced-choice recognition test of identity (i.e., recognition that a person's face was seen before). JOLs were higher for studied faces with happy and angry emotional expressions than for neutral faces. However, neutral test faces with studied neutral expressions had significantly higher identity recognition rates than neutral test faces studied with happy or angry expressions. Thus, these data are the first to demonstrate that people believe happy and angry emotional expressions will lead to better identity recognition in the future relative to neutral expressions. This occurred despite the fact that neutral expressions elicited better identity recognition than happy and angry expressions. These findings contribute to the growing literature examining the interaction of cognition and emotion.

Evaluation of Electrochemical Migration on Printed Circuit Boards with Lead-Free and Tin-Lead Solder

NASA Astrophysics Data System (ADS)

He, Xiaofei; Azarian, Michael H.; Pecht, Michael G.

2011-09-01

To evaluate the current leakage and electrochemical migration behavior on printed circuit boards with eutectic tin-lead and lead-free solder, IPC B-24 comb structures were exposed to 65°C and 88% relative humidity conditions under direct-current (DC) bias for over 1500 h. These boards were processed with either Sn-3.0Ag-0.5Cu solder or Sn-37Pb solder. In addition to solder alloy, board finish (organic solderability preservative versus lead-free hot air solder leveling), spacing (25 mil versus 12.5 mil), and voltage (40 V versus 5 V bias) were also assessed by using in situ measurements of surface insulation resistance (SIR) and energy-dispersive spectroscopy after testing. It was shown that an initial increase of SIR was caused by consumption of electroactive species on the surface, intermittent drops of SIR were caused by dendritic growth, and a long-term SIR decline was caused by electrodeposition of a metallic layer. The prolonged SIR decline of Sn-3.0Ag-0.5Cu boards was simulated by three-dimensional (3D) progressive and instantaneous nucleation models, whose predictions were compared with experimental data. Sn-37Pb boards exhibited comigration of Sn, Pb, and Cu, while Sn-3.0Ag-0.5Cu boards incurred comigration of Sn, Ag, and Cu. Among the migrated species, Sn always dominated and was observed as either a layer or in polyhedral deposits, Pb was the most common element found in the dendrites, Cu was a minor constituent, and Ag migrated only occasionally. Compared with solder alloy, board finishes played a secondary role in affecting SIR due to their complexation with or dissolution into the solder. The competing effect between electric field and spacing was also investigated.

Sensory, psychological, and metabolic dysfunction in HIV-associated peripheral neuropathy: A cross-sectional deep profiling study

PubMed Central

Phillips, Tudor J.C.; Brown, Matthew; Ramirez, Juan D.; Perkins, James; Woldeamanuel, Yohannes W.; Williams, Amanda C. de C.; Orengo, Christine; Bennett, David L.H.; Bodi, Istvan; Cox, Sarah; Maier, Christoph; Krumova, Elena K.; Rice, Andrew S.C.

2014-01-01

HIV-associated sensory neuropathy (HIV-SN) is a frequent complication of HIV infection and a major source of morbidity. A cross-sectional deep profiling study examining HIV-SN was conducted in people living with HIV in a high resource setting using a battery of measures which included the following: parameters of pain and sensory symptoms (7 day pain diary, Neuropathic Pain Symptom Inventory [NPSI] and Brief Pain Inventory [BPI]), sensory innervation (structured neurological examination, quantitative sensory testing [QST] and intraepidermal nerve fibre density [IENFD]), psychological state (Pain Anxiety Symptoms Scale-20 [PASS-20], Depression Anxiety and Positive Outlook Scale [DAPOS], and Pain Catastrophizing Scale [PCS], insomnia (Insomnia Severity Index [ISI]), and quality of life (Short Form (36) Health Survey [SF-36]). The diagnostic utility of the Brief Peripheral Neuropathy Screen (BPNS), Utah Early Neuropathy Scale (UENS), and Toronto Clinical Scoring System (TCSS) were evaluated. Thirty-six healthy volunteers and 66 HIV infected participants were recruited. A novel triumvirate case definition for HIV-SN was used that required 2 out of 3 of the following: 2 or more abnormal QST findings, reduced IENFD, and signs of a peripheral neuropathy on a structured neurological examination. Of those with HIV, 42% fulfilled the case definition for HIV-SN (n = 28), of whom 75% (n = 21) reported pain. The most frequent QST abnormalities in HIV-SN were loss of function in mechanical and vibration detection. Structured clinical examination was superior to QST or IENFD in HIV-SN diagnosis. HIV-SN participants had higher plasma triglyceride, concentrations depression, anxiety and catastrophizing scores, and prevalence of insomnia than HIV participants without HIV-SN. PMID:24973717

Mixed valent stannide EuRuSn 3 - Structure, magnetic properties, and Mössbauer spectroscopic investigation

NASA Astrophysics Data System (ADS)

Harmening, Thomas; Hermes, Wilfried; Eul, Matthias; Pöttgen, Rainer

2010-02-01

The stannide EuRuSn 3 was synthesized by induction melting of the elements in a sealed tantalum tube in a water-cooled quartz glass sample chamber. The structure was refined on the basis of single crystal X-ray diffractometer data (LaRuSn 3 type, Pm3¯n, a = 976.0(1) pm, wR2 = 0.0399, 317 F2 values, and 13 variables). EuRuSn 3 shows modified Curie-Weiss behaviour in the temperature range 50-305 K with an experimental magnetic moment of 7.34(1) μB per formula unit. Thus, the europium atoms are not in a purely divalent state. Low field susceptibility measurement indicates a ferro- or ferrimagnetic ordering at TC = 11.2(2) K and magnetization measurements indicate EuRuSn 3 as a non-collinear ferro- or ferrimagnet. 151Eu Mössbauer spectroscopic measurements suggested one europium site to be static mixed valent with a Eu 2+/Eu 3+ ratio close to one and the other site purely divalent. This was supported by substituting the Eu 3+ atoms with Y 3+ in a sample with a composition of Eu 0.7Y 0.3RuSn 3 ( a = 971.24(8) pm, wR2 = 0.0485, 313 F2 values, 14 variables). The 119Sn Mössbauer spectra show a pronounced Gol'danskii-Karyagin effect in the paramagnetic range and a magnetic hyperfine field distribution at 4.2 K, due to the complex magnetic structure. The influence of the valence electron concentration on the europium valence was tested via Ru/Pd substitution. A EuRu 0.8Pd 0.2Sn 3 sample shows almost purely divalent europium.

Light Echoes and the Progenitor of SN 2016adj in Cen A

NASA Astrophysics Data System (ADS)

Sugerman, Ben

2015-10-01

Supernova (SN) 2016adj is the fifth closest SN to be discovered during the lifetime of HST. This event offers us a rich variety of rare and unique opportunities, including: (1) identifying the progenitor; (2) mapping the three-dimensional structure and chemical composition of the progenitor's circumstellar and the host galaxy's interstellar environments; (3) testing models of stellar mass loss and high-mass stellar evolution; and (4) measuring the distance to the host galaxy, Cen A. The progenitor field of the SN has been observed from the near-UV to the near-IR with WFC3, which will immediately allow us to accomplish the first science goal by identifying the progenitor (or establishing its upper limits) once a new image with the SN present is taken. Preliminary analyses of early-time spectra of SN 2016adj indicate its light is being extinguished by at least A(V)=2-4 magnitudes, meaning it is buried deep within the dust lane of Cen A. Echoes of the SN light off of this dust will allow us to produce high-resolution, three-dimensional maps of the structure and composition of the dust in and around the line-of-sight to the SN, which we will use (as explained in this proposal) to accomplish science goals (2)-(4) listed above. Please note that since echoes pass through a given point in space only once, data are permanently lost for each epoch that is not observed. While we will propose for continued observations in the Cycle 24 call for proposals, most of the science we propose cannot be achieved if the observations in this proposal are not taken before Cycle 24 begins.

Hierarchical Models for Type Ia Supernova Light Curves in the Optical and Near Infrared

NASA Astrophysics Data System (ADS)

Mandel, Kaisey; Narayan, G.; Kirshner, R. P.

2011-01-01

I have constructed a comprehensive statistical model for Type Ia supernova optical and near infrared light curves. Since the near infrared light curves are excellent standard candles and are less sensitive to dust extinction and reddening, the combination of near infrared and optical data better constrains the host galaxy extinction and improves the precision of distance predictions to SN Ia. A hierarchical probabilistic model coherently accounts for multiple random and uncertain effects, including photometric error, intrinsic supernova light curve variations and correlations across phase and wavelength, dust extinction and reddening, peculiar velocity dispersion and distances. An improved BayeSN MCMC code is implemented for computing probabilistic inferences for individual supernovae and the SN Ia and host galaxy dust populations. I use this hierarchical model to analyze nearby Type Ia supernovae with optical and near infared data from the PAIRITEL, CfA3, and CSP samples and the literature. Using cross-validation to test the robustness of the model predictions, I find that the rms Hubble diagram scatter of predicted distance moduli is 0.11 mag for SN with optical and near infrared data versus 0.15 mag for SN with only optical data. Accounting for the dispersion expected from random peculiar velocities, the rms intrinsic prediction error is 0.08-0.10 mag for SN with both optical and near infrared light curves. I discuss results for the inferred intrinsic correlation structures of the optical-NIR SN Ia light curves and the host galaxy dust distribution captured by the hierarchical model. The continued observation and analysis of Type Ia SN in the optical and near infrared is important for improving their utility as precise and accurate cosmological distance indicators.

Supernovae Discovery Efficiency

NASA Astrophysics Data System (ADS)

John, Colin

2018-01-01

Abstract:We present supernovae (SN) search efficiency measurements for recent Hubble Space Telescope (HST) surveys. Efficiency is a key component to any search, and is important parameter as a correction factor for SN rates. To achieve an accurate value for efficiency, many supernovae need to be discoverable in surveys. This cannot be achieved from real SN only, due to their scarcity, so fake SN are planted. These fake supernovae—with a goal of realism in mind—yield an understanding of efficiency based on position related to other celestial objects, and brightness. To improve realism, we built a more accurate model of supernovae using a point-spread function. The next improvement to realism is planting these objects close to galaxies and of various parameters of brightness, magnitude, local galactic brightness and redshift. Once these are planted, a very accurate SN is visible and discoverable by the searcher. It is very important to find factors that affect this discovery efficiency. Exploring the factors that effect detection yields a more accurate correction factor. Further inquires into efficiency give us a better understanding of image processing, searching techniques and survey strategies, and result in an overall higher likelihood to find these events in future surveys with Hubble, James Webb, and WFIRST telescopes. After efficiency is discovered and refined with many unique surveys, it factors into measurements of SN rates versus redshift. By comparing SN rates vs redshift against the star formation rate we can test models to determine how long star systems take from the point of inception to explosion (delay time distribution). This delay time distribution is compared to SN progenitors models to get an accurate idea of what these stars were like before their deaths.

Synthesis, spectral characterization and biological studies of some organotin(IV) complexes of L-proline, trans-hydroxy- L-proline and L-glutamine

NASA Astrophysics Data System (ADS)

Nath, Mala; Jairath, Ruchi; Eng, George; Song, Xueqing; Kumar, Ashok

2005-12-01

New organotin(IV) complexes of the general formula R 3Sn(L) (where R = Me, n-Bu and HL = L-proline; R = Me, Ph and HL = trans-hydroxy- L-proline and L-glutamine) and R 2Sn(L) 2 (where R = n-Bu, Ph and HL = L-proline; R = Ph, HL = trans-hydroxy- L-proline) have been synthesized by the reaction of R nSnCl 4- n (where n = 2 or 3) with sodium salt of the amino acid (HL). n-Bu 2Sn(Pro) 2 was synthesized by the reaction of n-Bu 2SnO with L-proline under azeotropic removal of water. The bonding and coordination behavior in these complexes have been discussed on the basis of IR and 119Sn Mössbauer spectroscopic studies in the solid-state. Their coordination behavior in solution has been discussed with the help of multinuclear ( 1H, 13C and 119Sn) NMR spectral studies. The 119Sn Mössbauer and IR studies indicate that L-proline and trans-hydroxy- L-proline show similar coordination behavior towards organotin(IV) compounds. Pentacoordinate trigonal-bipyramidal and hexacoordinate octahedral structures, respectively, have been proposed for the tri- and diorganotin(IV) complexes of L-proline and trans-hydroxy- L-proline, in which the carboxylate group acts as bidentate group. L-Glutamine shows different coordination behavior towards organotin(IV) compounds, it acts as monoanionic bidentate ligand coordinating through carboxylate and amino group. The triorganotin(IV) complexes of L-glutamine have been proposed to have trigonal-bipyramidal environment around tin. The newly synthesized complexes have been tested for their antiinflammatory and cardiovascular activities. Their LD 50 values are >1000 mg kg -1.

Aging Effects on Microstructure and Creep in Sn-3.8Ag-0.7Cu Solder

DTIC Science & Technology

2007-09-01

demonstrated that the primary creep data for ball joints can be fitted well to exponential law. Fit parameters for the tests accomplished at 250C...MICROSTRUCTURE AND CREEP IN Sn-3.8Ag-0.7Cu SOLDER by Orlando Cornejo September 2007 Thesis Advisor: Indranath Dutta THIS PAGE...collection of information, including suggestions for reducing this burden, to Washington headquarters Services , Directorate for Information

Micro-abrasion-corrosion behaviour of a biomedical Ti-25Nb-3Mo-3Zr-2Sn alloy in simulated physiological fluid.

PubMed

Wang, Zhenguo; Li, Yan; Huang, Weijiu; Chen, Xiaoli; He, Haoran

2016-10-01

The micro-abrasion-corrosion behaviour of the biomedical Ti-25Nb-3Mo-3Zr-2Sn alloy in Hank׳s solution with protein has been investigated using electrochemical measurements, tribological tests and scanning electron microscope (SEM) observations. The potentiodynamic polarization tests showed that the corrosion potential (Ecorr) exhibits the maximum value at the abrasive concentration of 0.05gcm(-3) despite of the load level. The tribological results indicated that the total material loss of the Ti-25Nb-3Mo-3Zr-2Sn alloy during micro-abrasion increased with the increasing abrasive concentration at a certain applied load. When the abrasive concentration is no more than 0.15gcm(-3), the total material loss increases with increasing load, while the total material loss exhibits the maximum value at a moderate load in case of higher abrasive concentration levels. This was ascribed to the three-body or two-body micro-abrasion-corrosion at different abrasive concentration levels. The wastage map, abrasion mode map and synergy map associated with the applied load and the abrasive concentration were constructed to evaluate the micro-abrasion-corrosion behaviour of the Ti-25Nb-3Mo-3Zr-2Sn alloy in potential biomedical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Using SN 1987A light echoes to determine mass loss from the progenitor

NASA Technical Reports Server (NTRS)

Crotts, Arlin P. S.; Kunkel, William E.

1991-01-01

The hypothesis that the blue progenitor of SN 1987A passed through a blue supergiant phase ending with the expulsion of the outer envelope is tested. The many light echoes seen near SN 1987A were used to search for a mass flow from the progenitor and for abrupt density changes at the limits of this smooth mass flow. The progenitor needed roughly a million yr to create these structures, assuming a constant mass loss at 15 km/s. The dust in the region is small-grained and isotropically scattering. Interaction between the progenitor blue supergiant and red supergiant winds is probably contained within a roughly spherical structure 1.5 pc in diameter.

Experiment requirements and implementation plan (Erip) for semiconductor materials growth in low-G environment

NASA Technical Reports Server (NTRS)

Crouch, R. K.; Fripp, A. L.; Debnam, W. J.; Clark, I. O.

1983-01-01

The MEA-2 A facility was used to test the effect of the low gravity environment on suppressing convective mixing in the growth of Pb(1-x)Sn(x)Te crystals. The need to eliminate convection, the furnace characteristics and operation that will be required for successful experimental implementation, and to the level that is presently known, the measured physical properties of the Pb(1-x)Sn(x)Te system were discussed. In addition, a brief background of the present and potential utilization of Pb(1-x)Sn(x)Te is given. Additional experiments are anticipated in future MEA-A, improved MEA and other dedicated materials processing in space flight apparatus.

Conduction band edge effective mass of La-doped BaSnO{sub 3}

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

James Allen, S., E-mail: allen@itst.ucsb.edu; Law, Ka-Ming; Raghavan, Santosh

2016-06-20

BaSnO{sub 3} has attracted attention as a promising material for applications requiring wide band gap, high electron mobility semiconductors, and moreover possesses the same perovskite crystal structure as many functional oxides. A key parameter for these applications and for the interpretation of its properties is the conduction band effective mass. We measure the plasma frequency of La-doped BaSnO{sub 3} thin films by glancing incidence, parallel-polarized resonant reflectivity. Using the known optical dielectric constant and measured electron density, the resonant frequency determines the band edge electron mass to be 0.19 ± 0.01. The results allow for testing band structure calculations and transport models.

Montreal Cognitive Assessment for screening mild cognitive impairment: variations in test performance and scores by education in Singapore.

PubMed

Ng, Tze Pin; Feng, Lei; Lim, Wee Shiong; Chong, Mei Sian; Lee, Tih Shih; Yap, Keng Bee; Tsoi, Tung; Liew, Tau Ming; Gao, Qi; Collinson, Simon; Kandiah, Nagaendran; Yap, Philip

2015-01-01

The Montreal Cognitive Assessment (MoCA) was developed as a screening instrument for mild cognitive impairment (MCI). We evaluated the MoCA's test performance by educational groups among older Singaporean Chinese adults. The MoCA and Mini-Mental State Examination (MMSE) were evaluated in two independent studies (clinic-based sample and community-based sample) of MCI and normal cognition (NC) controls, using receiver operating characteristic curve analyses: area under the curve (AUC), sensitivity (Sn), and specificity (Sp). The MoCA modestly discriminated MCI from NC in both study samples (AUC = 0.63 and 0.65): Sn = 0.64 and Sp = 0.36 at a cut-off of 28/29 in the clinic-based sample, and Sn = 0.65 and Sp = 0.55 at a cut-off of 22/23 in the community-based sample. The MoCA's test performance was least satisfactory in the highest (>6 years) education group: AUC = 0.50 (p = 0.98), Sn = 0.54, and Sp = 0.51 at a cut-off of 27/28. Overall, the MoCA's test performance was not better than that of the MMSE. In multivariate analyses controlling for age and gender, MCI diagnosis was associated with a <1-point decrement in MoCA score (η(2) = 0.010), but lower (1-6 years) and no education was associated with a 3- to 5-point decrement (η(2) = 0.115 and η(2) = 0.162, respectively). The MoCA's ability to discriminate MCI from NC was modest in this Chinese population, because it was far more sensitive to the effect of education than MCI diagnosis. © 2015 S. Karger AG, Basel.

[The significance of directional preponderance in the evaluation of vestibular function in patients with vertigo].

PubMed

Wang, J; Zhou, Y J; Yu, J; Gu, J

2017-03-07

Objective: To analyze the relationship between directional preponderance (DP), spontaneous nystagmus(SN) and vestibular disorders, and to investigate the significance of DP in directing peripheral vestibular function in patients with vertigo. Methods: This was a retrospective analysis of 394 cases diagnosed with peripheral vestibular disease accompanied by vertigo from March 2012 to June 2014 in the Outpatient Department of the Eye & ENT Hospital of Fudan University. Results of static and dynamic posture equilibrium tests, SN, unilateral weakness(UW), and DP in videonystagmography(VNG) were analyzed and compared. Results: The mean interval time between the last vertigo attack and examination in patients with SN or DP in caloric test were 4.4 d and 7.3 d respectively, and those without SN or DP were 18.3 d and 17.5 d respectively. The patients were divided into two groups according to DP results of caloric test. DP-normal group had 203 cases and DP-abnormal group had 191 cases. Spontaneous nystagmus was presented in 44 cases in the DP-normal group (21.67%) and four in the DP-abnormal group (2.09%). A significant difference was found between the two groups (χ 2 =35.27, P =0.000). Deficiency of vestibular function was noted in 165 cases in the DP-normal group (81.28%) and 123 (64.40%) in the DP-abnormal group in static and dynamic posture equilibrium tests. The difference between the two groups was statistically significant (χ 2 =14.26, P =0.000). Conclusion: Compared with DP-normal patients, DP-abnormal patients are more likely to have spontaneous nystagmus and balance disorders due to vestibular dysfunction.

Communal nesting exerts epigenetic influences on affective and social behaviors in rats selectively bred for an infantile trait.

PubMed

Martinez, Ashley Rae; Brunelli, Susan A; Zimmerberg, Betty

2015-02-01

Communal nesting (CN) is a mouse model of early social enrichment during pregnancy and lactation. In this study, a rat model of CN was developed to determine if CN exerts an epigenetic effect in rats selectively bred for an infantile affective trait (high and low rates of ultrasonic distress calls). High and Low offspring from CN groups were compared to standard reared (SN) offspring on five measures of social and affective behavior at three critical ages. A differential effect of the CN paradigm on High and Low lines was seen in measures of anxiety and arousal, but not in measures of depression or social behavior. Neonatal CN subjects emitted fewer distress calls than SN subjects when separated from their dams, and the High line subjects were more affected by the CN procedure. As juveniles, CN subjects showed increased social behaviors in tests of juvenile parenting and play compared to SN subjects. In adulthood, CN differentially increased the activity of Low line subjects. All CN subjects displayed less anxiety behavior in an open field compared to SN subjects; High line subjects were more anxious than Lows. CN reduced immobility and increased attempts to escape on the Porsolt forced swim task relative to SN subjects. These results extend the usefulness of this early enrichment paradigm from mice to rats, and found some rodent species differences in outcomes dependent on the behavioral test. They also emphasize the importance of social contact during pregnancy and lactation on offspring's optimal development across behaviors and ages. Copyright © 2014 Elsevier Inc. All rights reserved.

The Effect of Microgravity Direction on the Growth of PbSnTe

NASA Technical Reports Server (NTRS)

Fripp, A. L.; Debnam, W. J.; Rosch, W. R.; Narayanan, R.

1998-01-01

The Space Shuttle Columbia was launched as STS-75 at 2018 GMT (Greenwich Mean Time) on February 22, 1996. One of the two major experiment packages was the Third United States Microgravity Payload (USMP-3), and one of the principal instruments on the USMP was the Advanced Automated Directional Solidification Furnace (AADSF). The AADSF is a multizone directional solidification furnace, and at the time of the USMP-3 flight was capable of processing only one sample per Shuttle mission which, for that flight, was a lead tin telluride (PbSnTe) crystal growth experiment. In the one year since the flight experiment the sample has been retrieved from the spacecraft and analysis has begun. After presenting introductory material on why PbSnTe was chosen as a test material, why microgravity processing was expected to produce desired results, and what we expected to find in conducting these tests, this report discusses the results to date which are far from complete.

Massive stars dying alone: the extremely remote environment of SN 2009ip

NASA Astrophysics Data System (ADS)

Smith, Nathan; Andrews, Jennifer E.; Mauerhan, Jon C.

2016-12-01

We present late-time Hubble Space Telescope (HST) images of the site of supernova (SN) 2009ip taken almost 3 yr after its bright 2012 luminosity peak. SN 2009ip is now slightly fainter in broad filters than the progenitor candidate detected by HST in 1999. The current source continues to be dominated by ongoing late-time circumstellar material interaction that produces strong Hα emission and a weak pseudo-continuum, as found previously for 1-2 yr after explosion. The intent of these observations was to search for evidence of recent star formation in the local (˜1 kpc; 10 arcsec) environment around SN 2009ip, in the remote outskirts of its host spiral galaxy NGC 7259. We can rule out the presence of any massive star-forming complexes like 30 Dor or the Carina nebula at the SN site or within a few kpc. If the progenitor of SN 2009ip was really a 50-80 M⊙ star as archival HST images suggested, then it is strange that there is no sign of this type of massive star formation anywhere in the vicinity. A possible explanation is that the progenitor was the product of a merger or binary mass transfer, rejuvenated after a lifetime that was much longer than 4-5 Myr, allowing its natal H II region to have faded. A smaller region like the Orion nebula would be an unresolved but easily detected point source. This is ruled out within ˜1.5 kpc around SN 2009ip, but a small H II region could be hiding in the glare of SN 2009ip itself. Later images after a few more years have passed are needed to confirm that the progenitor candidate is truly gone and to test for the possibility of a small H II region or cluster at the SN position.

First report of vertically aligned (Sn,Ir)O2:F solid solution nanotubes: Highly efficient and robust oxygen evolution electrocatalysts for proton exchange membrane based water electrolysis

NASA Astrophysics Data System (ADS)

Ghadge, Shrinath Dattatray; Patel, Prasad P.; Datta, Moni K.; Velikokhatnyi, Oleg I.; Shanthi, Pavithra M.; Kumta, Prashant N.

2018-07-01

One dimensional (1D) vertically aligned nanotubes (VANTs) of (Sn0.8Ir0.2)O2:10F are synthesized for the first time by a sacrificial template assisted approach. The aim is to enhance the electrocatalytic activity of F doped (Sn,Ir)O2 solid solution electrocatalyst for oxygen evolution reaction (OER) in proton exchange membrane (PEM) based water electrolysis by generating (Sn0.8Ir0.2)O2:10F nanotubes (NTs). The 1D vertical channels and the high electrochemically active surface area (ECSA ∼38.46 m2g-1) provide for facile electron transport. This results in low surface charge transfer resistance (4.2 Ω cm2), low Tafel slope (58.8 mV dec-1) and excellent electrochemical OER performance with ∼2.3 and ∼2.6 fold higher electrocatalytic activity than 2D thin films of (Sn0.8Ir0.2)O2:10F and benchmark IrO2 electrocatalysts, respectively. Furthermore, (Sn0.8Ir0.2)O2:10F NTs exhibit excellent mass activity (21.67 A g-1), specific activity (0.0056 mAcm-2) and TOF (0.016 s-1), which is ∼2-2.6 fold higher than thin film electrocatalysts at an overpotential of 270 mV, with a total mass loading of 0.3 mg cm-2. In addition, (Sn0.8Ir0.2)O2:10F NTs demonstrate remarkable electrochemical durability - comparable to thin films of (Sn0.8Ir0.2)O2:10F and pure IrO2, operated under identical testing conditions in PEM water electrolysis. These results therefore indicate promise of (Sn0.8Ir0.2)O2:10F NTs as OER electrocatalysts for efficient and sustainable hydrogen production.

Al and Si Alloying Effect on Solder Joint Reliability in Sn-0.5Cu for Automotive Electronics

NASA Astrophysics Data System (ADS)

Hong, Won Sik; Oh, Chulmin; Kim, Mi-Song; Lee, Young Woo; Kim, Hui Joong; Hong, Sung Jae; Moon, Jeong Tak

2016-12-01

To suppress the bonding strength degradation of solder joints in automotive electronics, we proposed a mid-temperature quaternary Pb-free Sn-0.5Cu solder alloy with minor Pd, Al, Si and Ge alloying elements. We manufactured powders and solder pastes of Sn-0.5Cu-(0.01,0.03)Al-0.005Si-(0.006-0.007)Ge alloys ( T m = 230°C), and vehicle electronic control units used for a flame-retardant-4 printed circuit board with an organic solderability preservative finish were assembled by a reflow soldering process. To investigate the degradation properties of solder joints used in engine compartments, thermal cycling tests were conducted from -40°C to 125°C (10 min dwell) for 1500 cycles. We also measured the shear strength of the solder joints in various components and observed the microstructural evolution of the solder joints. Based on these results, intermetallic compound (IMC) growth at the solder joints was suppressed by minor Pd, Al and Si additions to the Sn-0.5Cu alloy. After 1500 thermal cycles, IMC layers thicknesses for 100 parts per million (ppm) and 300 ppm Al alloy additions were 6.7 μm and 10 μm, compared to the as-reflowed bonding thicknesses of 6 μm and 7 μm, respectively. Furthermore, shear strength degradation rates for 100 ppm and 300 ppm Al(Si) alloy additions were at least 19.5%-26.2%. The cause of the improvement in thermal cycling reliability was analyzed using the (Al,Cu)-Sn, Si-Sn and Al-Sn phases dispersed around the Cu6Sn5 intermetallic at the solder matrix and bonding interfaces. From these results, we propose the possibility of a mid-temperature Sn-0.5Cu(Pd)-Al(Si)-Ge Pb-free solder for automotive engine compartment electronics.

Impressive Suppression of Colon Cancer Growth by Triple Combination SN38/EF24/Melatonin: "Oncogenic" Versus "Onco-Suppressive" Reactive Oxygen Species.

PubMed

Bakalova, Rumiana; Zhelev, Zhivko; Shibata, Sayaka; Nikolova, Biliana; Aoki, Ichio; Higashi, Tatsuya

2017-10-01

The study aimed to investigate the effect of multi-targeted combinations (SN38/EF24; SN38/EF24/melatonin) on the growth of colon cancer in experimental animals and their impact on the ratio "oncogenic"/"onco-suppressive" reactive oxygen species (ROS) - a crucial factor for triggering carcinogenesis, as well as for development of effective therapeutic strategies. The experiments were conducted on colon cancer-grafted mice - non-treated, SN38/EF24-treated and SN38/EF24/melatonin-treated within 22 days. The balance between different types of ROS was measured in vivo by nitroxide-enhanced magnetic resonance imaging (MRI), as well as on isolated tissue specimens by conventional analytical tests. Both combinations significantly suppressed the tumor growth. Impressive anticancer effect was observed in SN38/EF24/melatonin-treated mice - almost complete destruction of the tumor. Both types of ROS (superoxide and hydroperoxides) were elevated in cancer, but the MRI data suggest that the ratio between them tends towards superoxide. SN38/EF24 decreased the level of superoxide, but did not affect the level of hydroperoxides in the cancerous tissue, while SN38/EF24/melatonin decreased the level of superoxide below the control and increased significantly the level of hydroperoxides. The most important observations are that: (i) colon cancer was characterized by a vicious cycle, that ensures a permanent domination of "oncogenic" ROS (as superoxide) over "onco-suppressive" ROS (as hydrogen peroxide); (ii) the anticancer effect of the triple combination EF24/SN38/melatonin was accompanied by decreasing "oncogenic" and increasing "onco-suppressive" ROS; (iii) the ratio between both types of ROS could be a new onco-target for combined therapy; and (iv) nitroxide-enhanced MRI is a valuable tool for analyzing of this ratio. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

[Reference values for the vestibulo-ocular reflex response to the head shaking and the bithermal caloric tests].

PubMed

Molina, M I; Zapata, C; Palma, M J; López-Escámez, J A

2006-01-01

To obtain reference values for the vestibulo-ocular reflex response to the head-shaking nystagmus and the bithermal caloric test in the spanish population. A descriptive study. SET UP: General hospital. One hundred and seven healthy sex and age stratified voluntiers were included. The final sample included 97 individuals over 18 years of age. Spontaneous nystagmus (SN), head-shaking nystagmus (HSN) and caloric induced nystagmus were explored. The eyes movement was recorded by a video-oculographic system. The SN or HSN was considered significant when at least 6 consecutive beats with a slow phase velocity of 2 degrees/sec were detected. The caloric test was performed with water flow at 250mL/20 s at 30 degrees C and 44 degrees C with an interval of 10 minutes between irrigations. The percentage of canal paresis (CP) and directional preponderance (DP) was calculated using maximum slow phase velocity and the Jongkees index formula. Presence of SN, horizontal and vertical SHN, percentage of CP and DP. SN was found in 10,3% individuals (6 women and 4 men). Horizontal HSN was also observed in 9 women and 10 men (19,5%), and vertical HSN in 8 women and 10 men (18,6%). The mean and 95 percentil for CP were 13,10 and 28,60 in women and 11,02 and 27,30 in men. For DP, the mean and 95 percentil were 11,76 and 35,80 in women and 11,58 and 28,65 in men. The 5 percentils for slow phase velocity of nystagmus after each irrigation were 6,30; 5,14; 5,96; 4,02 degrees/s (left ear 44 degrees, right ear 44 degrees, left ear 30 degrees, right ear 30 degrees, respectively) in the group of women; and 5,82; 6,99; 5,67; 4,55 degrees/s in men (with the same irrigation sequence). Results presented should be considered as a population-based norms and may be useful as references for water bithermal test for VOG studies. The SN or HSN could be observed in subjects without vestibular pathology.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report, METSAT (S/N:107) AMSU-A1 Receiver Assemblies: P/N 1356429-1, S/N:F04, P/N 1356409-1,S/N F04

NASA Technical Reports Server (NTRS)

Pines, D.

1999-01-01

This is the Performance Verification Report, METSAT (S/N: 107) AMSU-A1 Receiver Assemblies, P/N 1356429-1, SIN: F04, P/N 1356409- 1, S/N: F04, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The AMSU-A receiver subsystem comprises two separated receiver assemblies; AMSU-A1 and AMSU-A2 (P/N 1356441-1). The AMSU-A1 receiver contains 13 channels and the AMSU-A2 receiver 2 channels. The AMSU-A receiver assembly is further divided into two parts; AMSU-A I - I (P/N 13 5 6429- 1) and AMSU-A 1 -2 (P/N 1356409-1), which contain 9 and 4 channels, respectively. The AMSU-A receiver subsystem is located in between the antenna and signal processing subsystems of the AMSU-A instrument and comprises the RF and IF components from isolators to attenuators. It receives the RF signals from the antenna subsystem, down-converts the RF signals to IF signals, amplifies and defines the IF signals to proper power level and frequency bandwidth as specified for each channel, and inputs the IF signals to the signal processing subsystem. The test reports for the METSAT AMSU-A receiver subsystem are prepared separately for Al and A2 receivers so that each receiver stands alone during integration of instruments into the spacecraft. This test report presents the test data of the N4ETSAT AMSU-A1 Flight Model No. 4 (FM-4) receiver subsystem. The tests are performed per the Acceptance Test Procedure (ATP) for the AMSU-A Receiver Subsystem, AE-26002/6A. The functional performance tests are conducted either at the component or subsystem level. While the component-level tests are performed over the entire operating temperature range predicted by thermal analysis, most subsystem-level tests are conducted at ambient temperature only. Key performances (bandpass characteristics and noise figure) of the receiver subsystem are verified over the operating temperature.

Ceramic Technology Project data base: September 1992 summary report

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

Keyes, B.L.P.

Data presented in this report represent an intense effort to improve processing methods, testing methods, and general mechanical properties (rupture modulus, tensile, creep, stress-rupture, dynamic and cyclic fatigue, fracture toughness) of candidate ceramics for use in advanced heat engines. This work was performed by many facilities and represents only a small part of the data generated by the Ceramic Technology Project (CTP) since 1986. Materials discussed include GTE PY6, GN-10, NT-154, NT-164, SN-260, SN-251, SN-252, AY6, silicon nitride combined with rare-earth oxides, Y-TZP, ZTA, NC-433, NT-230, Hexoloy SA, MgO-PSZ-to-MgO-PSZ joints, MgO-PSZ-to-cast iron, and a few whisker/fiber-reinforced ceramics. Information in thismore » report was taken from the project`s semiannual and bimonthly progress reports and from final reports summarizing the results of individual studies. Test results are presented in tabular form and in graphs. All data, including test rig descriptions and material characterizations, are stored in the CTP data base and are available to all project participants on request. The objective of this report is to make available the test results from these studies but not to draw conclusions from those data.« less

SN-1 and NEMO: the Italian cabled observatories

NASA Astrophysics Data System (ADS)

Favali, P.; Beranzoli, L.; Calore, D.; D'Anna, G.; Gasparoni, F.; NEMO Collaboration Team

2003-04-01

A fruitful synergy between Geophysics, Environmental Sciences, Nuclear Physics and Marine Technology has started through ongoing projects within different Italian research frameworks. The Neutrino Mediterranean Observatory (NEMO) project, funded by INFN, aims at the realization of a deep-sea experiment for the detection of cosmic neutrinos using an array of towers equipped by photosensors. To test the technological solutions proposed for the realization of the project, the Laboratiori Nazionali del Sud have set up an underwater Test Site off-shore Catania. A 25 km long submarine electro-optical cable was deployed in September 2001, in order to supply power from land and receive data from the underwater site located at a depth of 2000 m. A shore station has also been realize inside the Catania port area. In October 2001, Submarine Network-1 (SN-1), the first Italian deep-sea multidisciplinary observatory for geophysical and environmental monitoring was deployed at a depth of 2105 m, in the area of the Ibleo-maltese escarpment, in proximity of the marine tail of the NEMO cable. SN-1, funded by the Italian Gruppo Nazionale di Difesa dai Terremoti and coordinated by INGV, is presently operating in local mode storing measurements on hard disks and is powered by lithium batteries with an autonomy of approximately 200 days. In the view of mutual assistance, the coordinator institutions of NEMO and SN-1 have agreed that part of the optic fibres and power lines of the NEMO-1 underwater cable be made available to power SN-1 from land and to transfer in real time the signals acquired by the geophysical and environmental sensor packages of SN-1. On this latter's side, time series of environmental parameters useful for the analysis and interpretation of NEMO-1 detections will be available. A description of the two projects and of the 'state of the art' will be given and the benefits of the development of a submarine Italian prone site will be pointed out.

Critical Synergistic Concentration of Lecithin Phospholipids Improves the Antimicrobial Activity of Eugenol against Escherichia coli

PubMed Central

Zhang, Haoshu; Dudley, Edward G.

2017-01-01

ABSTRACT In this study, the effect of individual lecithin phospholipids on the antimicrobial properties of eugenol against Escherichia coli C600 was investigated. We tested five major phospholipids common in soy or egg lecithin (1,2-dihexadecanoyl-sn-glycero-3-phosphocholine [DPPC], 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine [DSPC], 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine [DPPE], 1,2-dihexadecanoyl-sn-glycero-3-phosphate [sodium salt] [DPPA], and 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine [DPPS]) and one synthetic cationic phospholipid (1,2-dioctadecanoyl-sn-glycero-3-ethylphosphocholine [18:0 EPC]). Among the six phospholipids, DPPC, DSPC, DPPE, DPPA, and the cationic 18:0 EPC showed critical synergistic concentrations that significantly improved the inactivation effect of eugenol against E. coli after 30 min of exposure. At the critical synergistic concentration, an additional ca. 0.4 to 1.9 log reduction (ca. 0.66 to 2.17 log CFU/ml reduction) in the microbial population was observed compared to eugenol-only (control) treatments (ca. 0.25 log reduction). In all cases, increasing the phospholipid amount above the critical synergistic concentration (which was different for each phospholipid) resulted in antimicrobial properties similar to those seen with the eugenol-only (control) treatments. DPPS did not affect the antimicrobial properties of eugenol at the tested concentrations. The critical synergistic concentration of phospholipids was correlated with their critical micelle concentrations (CMC). IMPORTANCE Essential oils (EOs) are naturally occurring antimicrobials, with limited use in food due to their hydrophobicity and strong aroma. Lecithin is used as a natural emulsifier to stabilize EOs in aqueous systems. We previously demonstrated that, within a narrow critical-concentration window, lecithin can synergistically enhance the antimicrobial properties of eugenol. Since lecithin is a mixture of different phospholipids, we aimed to identify which phospholipids are crucial for the observed synergistic effect. This research studied the bioactivity of lecithin phospholipids, contributing to a rational design in using lecithin to effectively control foodborne pathogens in foods. PMID:28842540

Thermal equilibrium concentration of intrinsic point defects in heavily doped silicon crystals - Theoretical study of formation energy and formation entropy in area of influence of dopant atoms-

NASA Astrophysics Data System (ADS)

Kobayashi, K.; Yamaoka, S.; Sueoka, K.; Vanhellemont, J.

2017-09-01

It is well known that p-type, neutral and n-type dopants affect the intrinsic point defect (vacancy V and self-interstitial I) behavior in single crystal Si. By the interaction with V and/or I, (1) growing Si crystals become more V- or I-rich, (2) oxygen precipitation is enhanced or retarded, and (3) dopant diffusion is enhanced or retarded, depending on the type and concentration of dopant atoms. Since these interactions affect a wide range of Si properties ranging from as-grown crystal quality to LSI performance, numerical simulations are used to predict and to control the behavior of both dopant atoms and intrinsic point defects. In most cases, the thermal equilibrium concentrations of dopant-point defect pairs are evaluated using the mass action law by taking only the binding energy of closest pair to each other into account. The impacts of dopant atoms on the formation of V and I more distant than 1st neighbor and on the change of formation entropy are usually neglected. In this study, we have evaluated the thermal equilibrium concentrations of intrinsic point defects in heavily doped Si crystals. Density functional theory (DFT) calculations were performed to obtain the formation energy (Ef) of the uncharged V and I at all sites in a 64-atom supercell around a substitutional p-type (B, Ga, In, and Tl), neutral (C, Ge, and Sn) and n-type (P, As, and Sb) dopant atom. The formation (vibration) entropies (Sf) of free I, V and I, V at 1st neighboring site from B, C, Sn, P and As atoms were also calculated with the linear response method. The dependences of the thermal equilibrium concentrations of trapped and total intrinsic point defects (sum of free I or V and I or V trapped with dopant atoms) on the concentrations of B, C, Sn, P and As in Si were obtained. Furthermore, the present evaluations well explain the experimental results of the so-called ;Voronkov criterion; in B and C doped Si, and also the observed dopant dependent void sizes in P and As doped Si crystals. The expressions obtained in the present work are very useful for the numerical simulation of grown-in defect behavior, oxygen precipitation and dopant diffusion in heavily doped Si. DFT calculations also showed that Coulomb interaction reaches approximately 30 Å from p (n)-type dopant atoms to I (V) in Si.

Metabolic, Reproductive, and Neurologic Abnormalities in Agpat1-Null Mice.

PubMed

Agarwal, Anil K; Tunison, Katie; Dalal, Jasbir S; Nagamma, Sneha S; Hamra, F Kent; Sankella, Shireesha; Shao, Xinli; Auchus, Richard J; Garg, Abhimanyu

2017-11-01

Defects in the biosynthesis of phospholipids and neutral lipids are associated with cell membrane dysfunction, disrupted energy metabolism, and diseases including lipodystrophy. In these pathways, the 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT) enzymes transfer a fatty acid to the sn-2 carbon of sn-1-acylglycerol-3-phosphate (lysophosphatidic acid) to form sn-1, 2-acylglycerol-3-phosphate [phosphatidic acid (PA)]. PA is a precursor for key phospholipids and diacylglycerol. AGPAT1 and AGPAT2 are highly homologous isoenzymes that are both expressed in adipocytes. Genetic defects in AGPAT2 cause congenital generalized lipodystrophy, indicating that AGPAT1 cannot compensate for loss of AGPAT2 in adipocytes. To further explore the physiology of AGPAT1, we characterized a loss-of-function mouse model (Agpat1-/-). The majority of Agpat1-/- mice died before weaning and had low body weight and low plasma glucose levels, independent of plasma insulin and glucagon levels, with reduced percentage of body fat but not generalized lipodystrophy. These mice also had decreased hepatic messenger RNA expression of Igf-1 and Foxo1, suggesting a decrease in gluconeogenesis. In male mice, sperm development was impaired, with a late meiotic arrest near the onset of round spermatid production, and gonadotropins were elevated. Female mice showed oligoanovulation yet retained responsiveness to gonadotropins. Agpat1-/- mice also demonstrated abnormal hippocampal neuron development and developed audiogenic seizures. In summary, Agpat1-/- mice developed widespread disturbances of metabolism, sperm development, and neurologic function resulting from disrupted phospholipid homeostasis. AGPAT1 appears to serve important functions in the physiology of multiple organ systems. The Agpat1-deficient mouse provides an important model in which to study the contribution of phospholipid and triacylglycerol synthesis to physiology and diseases. Copyright © 2017 Endocrine Society.

Enhanced pneumonia and disease in pigs vaccinated with an inactivated human-like (δ-cluster) H1N2 vaccine and challenged with pandemic 2009 H1N1 influenza virus.

PubMed

Gauger, Phillip C; Vincent, Amy L; Loving, Crystal L; Lager, Kelly M; Janke, Bruce H; Kehrli, Marcus E; Roth, James A

2011-03-24

Influenza is an economically important respiratory disease affecting swine world-wide with potential zoonotic implications. Genetic reassortment and drift has resulted in genetically and antigenically distinct swine influenza viruses (SIVs). Consequently, prevention of SIV infection is challenging due to the increased rate of genetic change and a potential lack of cross-protection between vaccine strains and circulating novel isolates. This report describes a vaccine-heterologous challenge model in which pigs were administered an inactivated H1N2 vaccine with a human-like (δ-cluster) H1 six and three weeks before challenge with H1 homosubtypic, heterologous 2009 pandemic H1N1. At necropsy, macroscopic and microscopic pneumonia scores were significantly higher in the vaccinated and challenged (Vx/Ch) group compared to non-vaccinated and challenged (NVx/Ch) pigs. The Vx/Ch group also demonstrated enhanced clinical disease and a significantly elevated pro-inflammatory cytokine profile in bronchoalveolar lavage fluid compared to the NVx/Ch group. In contrast, viral shedding and replication were significantly higher in NVx/Ch pigs although all challenged pigs, including Vx/Ch pigs, were shedding virus in nasal secretions. Hemagglutination inhibition (HI) and serum neutralizing (SN) antibodies were detected to the priming antigen in the Vx/Ch pigs but no measurable cross-reacting HI or SN antibodies were detected to pandemic H1N1 (pH1N1). Overall, these results suggest that inactivated SIV vaccines may potentiate clinical signs, inflammation and pneumonia following challenge with divergent homosubtypic viruses that do not share cross-reacting HI or SN antibodies. Published by Elsevier Ltd.

Erosion-protecting effect of oral-care products available on the Swiss market. A pilot study

PubMed

Wasser, Gregor; João-Souza, Samira H; Lussi, Adrian; Carvalho, Thiago S

2018-03-28

The present study sought to test oral-care products available on the Swiss market, such as toothpastes and gels, with respect to the protection of enamel against erosive tooth wear. A total of 56 enamel specimens were divided into 7 groups (n = 8): F-TP = Migros Budget Anti-Caries Toothpaste (Negative Control); F+Sn3500-TP = Elmex Erosion Protection Toothpaste (Positive Control); F-TP + F+Oligopep-Gel = Migros Budget Anti-Caries Toothpaste + Emofluor Protect Gel Professional; F+Sn3120-Gel = Emofluor Gel Intensive Care; F+Oligopep-TP = Candida Protect Professional Toothpaste; F+Sn1260-TP = Emoform-F Protect Toothpaste; and F+Sn3440-TP = Sensodyne Repair & Protect Toothpaste. The specimens were incubated in artificial saliva for 30 min and then brushed in a toothbrushing machine (10 s brushing; total 2 min exposure to the product). After the toothbrush abrasion, the specimens were rinsed, dried and submitted to an erosive challenge (2 min; 1% citric acid; pH 3.6). This sequence was repeated 4 times, and the total enamel surface loss was calculated using indentation measurements before and after the brushing period. All groups presented progressive surface loss throughout the experiment; after 4 cycles, total surface loss values ranged from 0.11 µm (F+Sn3120-Gel) to 0.89 µm (F+Sn1260-TP). Regarding the total surface loss values (median; interquartile range), F-TP (0.54; 0.42–0.59) presented no significant differences compared to any of the other groups. F+Sn3500-TP (0.33; 0.30–0.40), F-TP + F+Oligopep-Gel (0.34; 0.29–0.42) and F+Sn3120-Gel (0.11; 0.09–0.15) presented lower surface loss than F+Oligopep-TP (0.75; 0.59–0.98), F+Sn1260-TP (0.89; 0.68–1.13) and F+Sn3440-TP (0.69; 0.66–0.78). Conclusion: Although some of the oral-care products containing stannous ions or oligopeptide-104 presented numerically lower SL values, they did not present significantly better protection than a regular fluoride toothpaste. The gels showed a general trend of better enamel protection against ETW.

Effects of salience-network-node neurofeedback training on affective biases in major depressive disorder.

PubMed

Hamilton, J Paul; Glover, Gary H; Bagarinao, Epifanio; Chang, Catie; Mackey, Sean; Sacchet, Matthew D; Gotlib, Ian H

2016-03-30

Neural models of major depressive disorder (MDD) posit that over-response of components of the brain's salience network (SN) to negative stimuli plays a crucial role in the pathophysiology of MDD. In the present proof-of-concept study, we tested this formulation directly by examining the affective consequences of training depressed persons to down-regulate response of SN nodes to negative material. Ten participants in the real neurofeedback group saw, and attempted to learn to down-regulate, activity from an empirically identified node of the SN. Ten other participants engaged in an equivalent procedure with the exception that they saw SN-node neurofeedback indices from participants in the real neurofeedback group. Before and after scanning, all participants completed tasks assessing emotional responses to negative scenes and to negative and positive self-descriptive adjectives. Compared to participants in the sham-neurofeedback group, from pre- to post-training, participants in the real-neurofeedback group showed a greater decrease in SN-node response to negative stimuli, a greater decrease in self-reported emotional response to negative scenes, and a greater decrease in self-reported emotional response to negative self-descriptive adjectives. Our findings provide support for a neural formulation in which the SN plays a primary role in contributing to negative cognitive biases in MDD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Genome-wide transcriptional responses of Alteromonas naphthalenivorans SN2 to contaminated seawater and marine tidal flat sediment.

PubMed

Jin, Hyun Mi; Jeong, Hye Im; Kim, Kyung Hyun; Hahn, Yoonsoo; Madsen, Eugene L; Jeon, Che Ok

2016-02-18

A genome-wide transcriptional analysis of Alteromonas naphthalenivorans SN2 was performed to investigate its ecophysiological behavior in contaminated tidal flats and seawater. The experimental design mimicked these habitats that either added naphthalene or pyruvate; tidal flat-naphthalene (TF-N), tidal flat-pyruvate (TF-P), seawater-naphthalene (SW-N), and seawater-pyruvate (SW-P). The transcriptional profiles clustered by habitat (TF-N/TF-P and SW-N/SW-P), rather than carbon source, suggesting that the former may exert a greater influence on genome-wide expression in strain SN2 than the latter. Metabolic mapping of cDNA reads from strain SN2 based on KEGG pathway showed that metabolic and regulatory genes associated with energy metabolism, translation, and cell motility were highly expressed in all four test conditions, probably highlighting the copiotrophic properties of strain SN2 as an opportunistic marine r-strategist. Differential gene expression analysis revealed that strain SN2 displayed specific cellular responses to environmental variables (tidal flat, seawater, naphthalene, and pyruvate) and exhibited certain ecological fitness traits -- its notable PAH degradation capability in seasonally cold tidal flat might be reflected in elevated expression of stress response and chaperone proteins, while fast growth in nitrogen-deficient and aerobic seawater probably correlated with high expression of glutamine synthetase, enzymes utilizing nitrite/nitrate, and those involved in the removal of reactive oxygen species.

Genome-wide transcriptional responses of Alteromonas naphthalenivorans SN2 to contaminated seawater and marine tidal flat sediment

PubMed Central

Jin, Hyun Mi; Jeong, Hye Im; Kim, Kyung Hyun; Hahn, Yoonsoo; Madsen, Eugene L.; Jeon, Che Ok

2016-01-01

A genome-wide transcriptional analysis of Alteromonas naphthalenivorans SN2 was performed to investigate its ecophysiological behavior in contaminated tidal flats and seawater. The experimental design mimicked these habitats that either added naphthalene or pyruvate; tidal flat-naphthalene (TF-N), tidal flat-pyruvate (TF-P), seawater-naphthalene (SW-N), and seawater-pyruvate (SW-P). The transcriptional profiles clustered by habitat (TF-N/TF-P and SW-N/SW-P), rather than carbon source, suggesting that the former may exert a greater influence on genome-wide expression in strain SN2 than the latter. Metabolic mapping of cDNA reads from strain SN2 based on KEGG pathway showed that metabolic and regulatory genes associated with energy metabolism, translation, and cell motility were highly expressed in all four test conditions, probably highlighting the copiotrophic properties of strain SN2 as an opportunistic marine r-strategist. Differential gene expression analysis revealed that strain SN2 displayed specific cellular responses to environmental variables (tidal flat, seawater, naphthalene, and pyruvate) and exhibited certain ecological fitness traits –– its notable PAH degradation capability in seasonally cold tidal flat might be reflected in elevated expression of stress response and chaperone proteins, while fast growth in nitrogen-deficient and aerobic seawater probably correlated with high expression of glutamine synthetase, enzymes utilizing nitrite/nitrate, and those involved in the removal of reactive oxygen species. PMID:26887987

Neutralizing Antibody Response in Dogs and Cats Inoculated with Commercial Inactivated Rabies Vaccines

PubMed Central

SHIRAISHI, Rikiya; NISHIMURA, Masaaki; NAKASHIMA, Ryuji; ENTA, Chiho; HIRAYAMA, Norio

2013-01-01

ABSTRACT In Japan, the import quarantine regulation against rabies has required from 2005 that dogs and cats should be inoculated with the rabies vaccine and that the neutralizing antibody titer should be confirmed to be at least 0.5 international units (IU)/ml. The fluorescent antibody virus neutralization (FAVN) test is used as an international standard method for serological testing for rabies. To achieve proper immunization of dogs and cats at the time of import and export, changes in the neutralizing antibody titer after inoculation of the rabies vaccine should be understood in detail. However, few reports have provided this information. In this study, we aimed to determine evaluated, such changes by using sera from experimental dogs and cats inoculated with the rabies vaccine, and we tested samples using the routine FAVN test. In both dogs and cats, proper, regular vaccination enabled the necessary titer of neutralizing antibodies to be maintained in the long term. However, inappropriate timing of blood sampling after vaccination could result in insufficient detected levels of neutralizing antibodies. PMID:24389741

Neutralizing antibody response in dogs and cats inoculated with commercial inactivated rabies vaccines.

PubMed

Shiraishi, Rikiya; Nishimura, Masaaki; Nakashima, Ryuji; Enta, Chiho; Hirayama, Norio

2014-04-01

In Japan, the import quarantine regulation against rabies has required from 2005 that dogs and cats should be inoculated with the rabies vaccine and that the neutralizing antibody titer should be confirmed to be at least 0.5 international units (IU)/ml. The fluorescent antibody virus neutralization (FAVN) test is used as an international standard method for serological testing for rabies. To achieve proper immunization of dogs and cats at the time of import and export, changes in the neutralizing antibody titer after inoculation of the rabies vaccine should be understood in detail. However, few reports have provided this information. In this study, we aimed to determine evaluated, such changes by using sera from experimental dogs and cats inoculated with the rabies vaccine, and we tested samples using the routine FAVN test. In both dogs and cats, proper, regular vaccination enabled the necessary titer of neutralizing antibodies to be maintained in the long term. However, inappropriate timing of blood sampling after vaccination could result in insufficient detected levels of neutralizing antibodies.

Exploring As-Cast PbCaSn-Mg Anodes for Improved Performance in Copper Electrowinning

NASA Astrophysics Data System (ADS)

Yuwono, Jodie A.; Clancy, Marie; Chen, Xiaobo; Birbilis, Nick

2018-06-01

Lead calcium tin (PbCaSn) alloys are the common anodes used in copper electrowinning (Cu EW). Given a large amount of energy consumed in Cu EW process, anodes with controlled oxygen evolution reaction (OER) kinetics and a lower OER overpotential are advantageous for reducing the energy consumption. To date, magnesium (Mg) has never been studied as an alloying element for EW anodes. As-cast PbCaSn anodes with the addition of Mg were examined herein, revealing an improved performance compared to that of the industrial standard PbCaSn anode. The alloy performances in the early stages of anode life and passivation were established from electrochemical studies which were designed to simulate industrial Cu EW process. The 24-hour polarization testing revealed that the Mg alloying depolarizes the anode potential up to 80 mV; thus, resulting in a higher Cu EW efficiency. In addition, scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the alteration of the alloy microstructure and the corresponding interfacial reactions contribute to the changes of the anode electrochemical performances. The present study reveals for the first time the potency of Mg alloying in reducing the overpotential of PbCaSn anode.

In-vitro antiviral activity of Solanum nigrum against Hepatitis C Virus

PubMed Central

2011-01-01

Background Hepatitis C is a major health problem causes liver cirrhosis, hepatocellular carcinoma and death. The current treatment of standard interferon in combination with ribavirin, has limited benefits due to emergence of resistant mutations during long-term treatment, adverse side effects and high cost. Hence, there is a need for the development of more effective, less toxic antiviral agents. Results The present study was designed to search anti-HCV plants from different areas of Pakistan. Ten medicinal plants were collected and tested for anti-HCV activity by infecting the liver cells with HCV 3a innoculum. Methanol and chloroform extracts of Solanum nigrum (SN) seeds exhibited 37% and more than 50% inhibition of HCV respectively at non toxic concentration. Moreover, antiviral effect of SN seeds extract was also analyzed against HCV NS3 protease by transfecting HCV NS3 protease plasmid into liver cells. The results demonstrated that chloroform extract of SN decreased the expression or function of HCV NS3 protease in a dose- dependent manner and GAPDH remained constant. Conclusion These results suggest that SN extract contains potential antiviral agents against HCV and combination of SN extract with interferon will be better option to treat chronic HCV. PMID:21247464

Fabrication and characterization of SnO2/ZnO gas sensors for detecting toluene gas.

PubMed

Min, Byung-Sam; Park, Young-Ho; Lee, Chang-Seop

2014-11-01

This study investigates the use of SnO2, ZnO, Ag, Au, Cu, In, Pd, Ru and carbon black to improve the sensitivity of a gas sensor for detecting toluene gas. Metal-SnO2/ZnO thick films were screen-printed onto Al2O3 substrates with platinum electrodes. The physico-chemical properties of the sensor materials were characterized using SEM/EDS, XRD, and BET analyses. Measuring the electrical resistance of each sensor as a function of the gas concentration determined the sensing characteristics. The sensors were tested using toluene, benzene, xylene, ethanol, methanol, ammonia and trimethylamine vapors with concentrations of 1-2000 ppm. The gas sensing properties of metal-SnO2/ZnO thick films depended on the content and variety of metals and the content of carbon black. The optimum condition of sensor material for toluene gas detection is operation temperature 300 degrees C and when metal catalyst Cu and carbon black were added. The best sensitivity and selectivity for toluene gas at 300 degrees C resulted from doping with 5 wt.% carbon black, 1 wt.% Cu and 20 wt.% ZnO to SnO2.

Evaluation on Dorsey Method in Surface Tension Measurement of Solder Liquids Containing Surfactants

NASA Astrophysics Data System (ADS)

Zhao, Xingke; Xie, Feiming; Fan, Jinsheng; Liu, Dayong; Huang, Jihua; Chen, Shuhai

2018-06-01

With the purpose of developing a feasible approach for measuring the surface tension of solders containing surfactants, the surface tension of Sn-3Ag-0.5Cu-xP solder alloys, with various drop sizes as well as different phosphorus (P) content, was evaluated using the Dorsey method based on the sessile drop test. The results show that the accuracy of the surface tension calculations depends on both of sessile drop size and the liquid metal composition. With a proper drop size, in the range of 4.5 mm to 5.3 mm in equivalent spherical diameters, the deviation of the surface tension calculation can be limited to 1.43 mN·m-1 and 6.30 mN·m-1 for SnAgCu and SnAgCu-P, respectively. The surface tension of SnAgCu-xP solder alloys decreases quickly to a minimum value when the P content reaches 0.5 wt% and subsequently increases slowly with the P content further increasing. The formation of a P-enriched surface layer and Sn4P3 intermetallic phases is regarded to be responsible for the decreasing and subsequent increasing of surface tension, respectively.

Computer simulation of solder joint failure

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

Burchett, S.N.; Frear, D.R.; Rashid, M.M.

The thermomechanical fatigue failure of solder joints is increasingly becoming an important reliability issue for electronic packages. The purpose of this Laboratory Directed Research and Development (LDRD) project was to develop computational tools for simulating the behavior of solder joints under strain and temperature cycling, taking into account the microstructural heterogeneities that exist in as-solidified near eutectic Sn-Pb joints, as well as subsequent microstructural evolution. The authors present two computational constitutive models, a two-phase model and a single-phase model, that were developed to predict the behavior of near eutectic Sn-Pb solder joints under fatigue conditions. Unique metallurgical tests provide themore » fundamental input for the constitutive relations. The two-phase model mathematically predicts the heterogeneous coarsening behavior of near eutectic Sn-Pb solder. The finite element simulations with this model agree qualitatively with experimental thermomechanical fatigue tests. The simulations show that the presence of an initial heterogeneity in the solder microstructure could significantly degrade the fatigue lifetime. The single-phase model was developed to predict solder joint behavior using materials data for constitutive relation constants that could be determined through straightforward metallurgical experiments. Special thermomechanical fatigue tests were developed to give fundamental materials input to the models, and an in situ SEM thermomechanical fatigue test system was developed to characterize microstructural evolution and the mechanical behavior of solder joints during the test. A shear/torsion test sample was developed to impose strain in two different orientations. Materials constants were derived from these tests. The simulation results from the two-phase model showed good fit to the experimental test results.« less

Value analysis of postoperative staging imaging for asymptomatic, early-stage breast cancer: implications of clinical variation on utility and cost.

PubMed

Pellet, Andrew C; Erten, Mujde Z; James, Ted A

2016-06-01

Routine staging imaging for early-stage breast cancer is not recommended. Despite this, there is clinical practice variation with imaging studies obtained for asymptomatic patients with a positive sentinel node (SN+). We characterize the utility, cost, and clinical implications of imaging studies obtained in asymptomatic SN+ patients. A retrospective review was performed of asymptomatic, clinically node-negative patients who were found to have a positive sentinel node after surgery. The type of imaging, subsequent tests/interventions, frequency of additional malignancy detected, and costs were recorded. From April 2009 to April 2013, a total of 50 of 113 (44%) asymptomatic patients underwent staging imaging for a positive sentinel node; 11 (22%) patients had at least 1 subsequent imaging study or diagnostic intervention. No instance of metastatic breast cancer was identified, with a total cost of imaging calculated at $116,905. Staging imaging for asymptomatic SN+ breast cancer demonstrates clinical variation. These tests were associated with low utility, increased costs, and frequent false positives leading to subsequent testing/intervention. Evidence-based standardization may help increase quality by decreasing unnecessary variation and cost. Copyright © 2015 Elsevier Inc. All rights reserved.

Toward a mechanistic understanding of the damage evolution of SnAgCu solder joints in accelerated thermal cycling test

NASA Astrophysics Data System (ADS)

Mahin Shirazi, Sam

Accelerated thermal cycling (ATC) tests are the most commonly used tests for the thermo-mechanical performance assessment of microelectronics assemblies. Currently used reliability models have failed to incorporate the microstructural dependency of lead free solder joint behavior and its microstructure evolution during cycling. Thus, it is essential to have a mechanistic understanding of the effect of cycling parameters on damage evolution and failure of lead free solder joints in ATC. Recrystallization has been identified as the damage rate controlling mechanism in ATC. Usually it takes 1/3 of life for completion of recrystallization regardless of cycling parameters. Thus, the life of the solder joints can be predicted by estimating global recrystallization. The objective of the first part of the study was to examine whether the damage scenario applies in service is the same as the harsh thermal cycling tests (i.e. 0/100 °C and -40/125 °C) commonly used in industry. Microstructure analysis results on a variety of lead free solder SnAgCu assemblies subjected to the both harsh (0/100 °C) and mild (20/80 °C) ATC confirmed similar failure mechanism under the both testing conditions. Sn grain morphology (interlaced versus beach ball) has a significant effect on the thermo-mechanical performance (and thus the model) of the lead free solder joints. The longer thermal cycling lifetime observed in the interlaced solder joints subjected to the ATC compared to the beach ball structure was correlated to the different initial microstructure and the microstructure evolution during cycling. For the modeling proposes, the present study was focused on Sn-Ag-Cu solder joints with either a single Sn grain or beach ball structure. Microstructural analysis results of the simulated thermal cycling experiment revealed that, the life can be approximated as determined by the accumulation of a certain amount of work during the high temperature dwells. Finally the effect of precipitates spacing on acceleration factor was investigated. Results indicated that a smaller initial precipitate spacing would tend to result in a longer life in mild thermal cycling/service (where there is lower stresses). Accordingly, it is essential to incorporate the dependence of damage rate (i.e. recrystallization) on precipitate coarsening in any predictions.

Epitope mapping of the U1 small nuclear ribonucleoprotein particle in patients with systemic lupus erythematosus and mixed connective tissue disease.

PubMed

Somarelli, J A; Mesa, A; Rodriguez, R; Avellan, R; Martinez, L; Zang, Y J; Greidinger, E L; Herrera, R J

2011-03-01

Systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) are autoimmune illnesses characterized by the presence of high titers of autoantibodies directed against a wide range of 'self ' antigens. Proteins of the U1 small nuclear ribonucleoprotein particle (U1 snRNP) are among the most immunogenic molecules in patients with SLE and MCTD. The recent release of a crystallized U1 snRNP provides a unique opportunity to evaluate the effects of tertiary and quaternary structures on autoantigenicity within the U1 snRNP. In the present study, an epitope map was created using the U1 snRNP crystal structure. A total of 15 peptides were tested in a cohort of 68 patients with SLE, 29 with MCTD and 26 healthy individuals and mapped onto the U1 snRNP structure. Antigenic sites were detected in a variety of structures and appear to include RNA binding domains, but mostly exclude regions necessary for protein-protein interactions. These data suggest that while some autoantibodies may target U1 snRNP proteins as monomers or apoptosis-induced, protease-digested fragments, others may recognize epitopes on assembled protein subcomplexes of the U1 snRNP. Although nearly all of the peptides are strong predictors of autoimmune illness, none were successful at distinguishing between SLE and MCTD. The antigenicity of some peptides significantly correlated with several clinical symptoms. This investigation implicitly highlights the complexities of autoimmune epitopes, and autoimmune illnesses in general, and demonstrates the variability of antigens in patient populations, all of which contribute to difficult clinical diagnoses.

Frontal facial proportions of 12-year-old southern Chinese: a photogrammetric study.

PubMed

Yeung, Charles Yat Cheong; McGrath, Colman Patrick; Wong, Ricky Wing Kit; Hägg, Erik Urban Oskar; Lo, John; Yang, Yanqi

2015-08-14

This study aimed to establish norm values for facial proportion indices among 12-year-old southern Chinese children, to determine lower facial proportion, and to identify gender differences in facial proportions.A random population sample of 514 children was recruited. Fifteen facial landmarks were plotted with ImageJ (V1.45) on standardized photos and 22 Facial proportion index values were obtained. Gender differences were analyzed by 2-sample t-test with 95% confidence interval. Repeated measurements were conducted on approximately 10% of the cases.The rate of adopted subjects was 52.5% (270/514). Intraclass correlation coefficient values (ICC) for intra- examiner reliability were >0.87. Population facial proportion index values were derived. Gender differences in 11 of the facial proportion indices were evident (P < 0.05).Upper face-face height (N- Sto/ N- Gn), vermilion height (Ls-Sto/Sto-Li), upper face height-biocular width (N-Sto/ExR-ExL) and nose -face height (N-Sn/N-Gn) indices were found to be larger among girls (P < 0.01). Males had larger lower face-face height (Sn -Gn/ N-Gn), mandibulo-face height (Sto-Gn/N-Gn), mandibulo-upper face height (Sto-Gn/N-Sto), nasal (AlR-AlL/N-Sn), upper lip height-mouth width (Sn-Sto/ChR-ChL), upper lip-upper face height (Sn-Sto/N-Sto) and upper lip-nose height (Sn-Sto/N-Sn) indices (P < 0.05).Population norm of facial proportion indices for 12-year-old Southern Chinese were derived and mean lower facial proportion were obtained. Sexual dimorphism is apparent.

Substantia nigra depigmentation and exposure to encephalitis lethargica.

PubMed

Hack, Nawaz; Jicha, Gregory A; Abell, Annalisa; Dean, Dawson; Vitek, Jerrold L; Berger, Joseph R

2012-12-01

Parkinsonism has occasionally been reported as a consequence of infectious diseases. The present study examines the clinical and pathological correlates of parkinsonism across birth cohorts in relation to critical exposure to the encephalitis lethargica epidemic in the early 1900s. The study population consisted of 678 participants in the Nun Study, of whom 432 died and came to autopsy. Qualitative indices of substantia nigra (SN) depigmentation were verified in a subset of 40 randomly selected subjects using quantitative stereological techniques. SN depigmentation, detected neuropathologically, was correlated with clinical parameters of Parkinson disease, age, and birth cohort. SN depigmentation was detected in 57 (13.2%) of the cohort. Although qualitative SN depigmentation correlated modestly with age (p = 0.02), it correlated best with birth cohort (p = 0.009) for women born in the years 1895-1899. Quantitative measures of SN depigmentation were increased in this birth cohort compared to age matched subjects from flanking birth cohorts 1890-1894 and 1900-1904 (p < 0.001). SN depigmentation correlated with speed of 6- and 50-foot walk (p < 0.0001), up and go test (p < 0.0001), and hand coordination (p < 0.0001). Subjects in the birth cohort 1895-1899 would have been in their late teens and 20s at the onset and during the peak of the encephalitis lethargica epidemic. These were precisely the age ranges of persons who were most often affected by the illness. These data suggest the possibility that the coexistence of parkinsonism and SN depigmentation in this birth cohort may have resulted from the yet undetermined infectious agent responsible for encephalitis lethargica. Copyright © 2012 American Neurological Association.

Development and evaluation of a Sarcocystis neurona-specific IgM capture enzyme-linked immunosorbent assay.

PubMed

Murphy, J E; Marsh, A E; Reed, S M; Meadows, C; Bolten, K; Saville, W J A

2006-01-01

Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses caused primarily by the protozoal parasite Sarcocystis neurona. Currently available antemortem diagnostic testing has low specificity. The hypothesis of this study was that serum and cerebrospinal fluid (CSF) of horses experimentally challenged with S neurona would have an increased S neurona-specific IgM (Sn-IgM) concentration after infection, as determined by an IgM capture enzyme linked immunoassay (ELISA). The ELISA was based on the S neurona low molecular weight protein SNUCD-1 antigen and the monoclonal antibody 2G5 labeled with horseradish peroxidase. The test was evaluated using serum and CSF from 12 horses experimentally infected with 1.5 million S neurona sporocysts and 16 horses experimentally infected with varying doses (100 to 100,000) of S neurona sporocysts, for which results of histopathologic examination of the central nervous system were available. For horses challenged with 1.5 million sporocysts, there was a significant increase in serum Sn-IgM concentrations compared with values before infection at weeks 2-6 after inoculation (P < .0001). For horses inoculated with lower doses of S neurona, there were significant increases in serum Sn-IgM concentration at various points in time after inoculation, depending on the challenge dose (P < .01). In addition, there was a significant increase between the CSF Sn-IgM concentrations before and after inoculation (P < .0001). These results support further evaluation of the assay as a diagnostic test during the acute phase of EPM.

Consequences of partial and severe dopaminergic lesion on basal ganglia oscillatory activity and akinesia.

PubMed

Tseng, Kuei Y; Kargieman, Lucila; Gacio, Sebastian; Riquelme, Luis A; Murer, M Gustavo

2005-11-01

Severe chronic dopamine (DA) depletion increases the proportion of neurons in the basal ganglia that fire rhythmic bursts of action potential (LFO units) synchronously with the cortical oscillations. Here we report on how different levels of mesencephalic DA denervation affect substantia nigra pars reticulata (SNpr) neuronal activity in the rat and its relationship to akinesia (stepping test). Chronic nigrostriatal lesion induced with 0 (control group), 4, 6 or 8 microg of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle resulted in a dose-dependent decrease of tyrosine hydroxylase positive (TH+) neurons in the SN and ventral tegmental area (VTA). Although 4 microg of 6-OHDA reduced the number of TH+ neurons in the SN by approximately 60%, both stepping test performance and SNpr neuronal activity remained indistinguishable from control animals. By contrast, animals that received 6 microg of 6-OHDA showed a marked reduction of TH+ cells in the SN ( approximately 75%) and VTA ( approximately 55%), a significant stepping test deficit and an increased proportion of LFO units. These changes were not dramatically enhanced with 8 microg 6-OHDA, a dose that induced an extensive DA lesion (> 95%) in the SN and approximately 70% reduction of DA neurons in the VTA. These results suggest a threshold level of DA denervation for both the appearance of motor deficits and LFO units. Thus, the presence of LFO activity in the SNpr is not related to a complete nigrostriatal DA neuron depletion (ultimate stage parkinsonism); instead, it may reflect a functional disruption of cortico-basal ganglia dynamics associated with clinically relevant stages of the disease.

Quantification of Lyssavirus-Neutralizing Antibodies Using Vesicular Stomatitis Virus Pseudotype Particles.

PubMed

Moeschler, Sarah; Locher, Samira; Conzelmann, Karl-Klaus; Krämer, Beate; Zimmer, Gert

2016-09-16

Rabies is a highly fatal zoonotic disease which is primarily caused by rabies virus (RABV) although other members of the genus Lyssavirus can cause rabies as well. As yet, 14 serologically and genetically diverse lyssaviruses have been identified, mostly in bats. To assess the quality of rabies vaccines and immunoglobulin preparations, virus neutralization tests with live RABV are performed in accordance with enhanced biosafety standards. In the present work, a novel neutralization test is presented which takes advantage of a modified vesicular stomatitis virus (VSV) from which the glycoprotein G gene has been deleted and replaced by reporter genes. This single-cycle virus was trans-complemented with RABV envelope glycoprotein. Neutralization of this pseudotype virus with RABV reference serum or immune sera from vaccinated mice showed a strong correlation with the rapid fluorescent focus inhibition test (RFFIT). Importantly, pseudotype viruses containing the envelope glycoproteins of other lyssaviruses were neutralized by reference serum to a significantly lesser extent or were not neutralized at all. Taken together, a pseudotype virus system has been successfully developed which allows the safe, fast, and sensitive detection of neutralizing antibodies directed against different lyssaviruses.

Frequency Spectrum Neutrality Tests: One for All and All for One

PubMed Central

Achaz, Guillaume

2009-01-01

Neutrality tests based on the frequency spectrum (e.g., Tajima's D or Fu and Li's F) are commonly used by population geneticists as routine tests to assess the goodness-of-fit of the standard neutral model on their data sets. Here, I show that these neutrality tests are specific instances of a general model that encompasses them all. I illustrate how this general framework can be taken advantage of to devise new more powerful tests that better detect deviations from the standard model. Finally, I exemplify the usefulness of the framework on SNP data by showing how it supports the selection hypothesis in the lactase human gene by overcoming the ascertainment bias. The framework presented here paves the way for constructing novel tests optimized for specific violations of the standard model that ultimately will help to unravel scenarios of evolution. PMID:19546320

Development of a High-Content Orthopoxvirus Infectivity and Neutralization Assays

PubMed Central

Gates, Irina; Olson, Victoria; Smith, Scott; Patel, Nishi; Damon, Inger; Karem, Kevin

2015-01-01

Currently, a number of assays measure Orthopoxvirus neutralization with serum from individuals, vaccinated against smallpox. In addition to the traditional plaque reduction neutralization test (PRNT), newer higher throughput assays are based on neutralization of recombinant vaccinia virus, expressing reporter genes such as β-galactosidase or green fluorescent protein. These methods could not be used to evaluate neutralization of variola virus, since genetic manipulations of this virus are prohibited by international agreements. Currently, PRNT is the assay of choice to measure neutralization of variola virus. However, PRNT assays are time consuming, labor intensive, and require considerable volume of serum sample for testing. Here, we describe the development of a high-throughput, cell-based imaging assay that can be used to measure neutralization, and characterize replication kinetics of various Orthopoxviruses, including variola, vaccinia, monkeypox, and cowpox. PMID:26426117

Evidence for Ni-56 yields Co-56 yields Fe-56 decay in type Ia supernovae

NASA Technical Reports Server (NTRS)

Kuchner, Marc J.; Kirshner, Robert P.; Pinto, Philip A.; Leibundgut, Bruno

1994-01-01

In the prevailing picture of Type Ia supernovae (SN Ia), their explosive burning produces Ni-56, and the radioactive decay chain Ni-56 yields Co-56 yields Fe-56 powers the subsequent emission. We test a central feature of this theory by measuring the relative strengths of a (Co III) emission feature near 5900 A and a (Fe III) emission feature near 4700 A. We measure 38 spectra from 13 SN Ia ranging from 48 to 310 days after maximum light. When we compare the observations with a simple multilevel calculation, we find that the observed Fe/Co flux ratio evolves as expected when the Fe-56/Co-56 abundance ratio follows from Ni-56 yields Co-56 yields Fe-56 decay. From this agreement, we conclude that the cobalt and iron atoms we observe through SN Ia emission lines are produced by the radioactive decay of Ni-56, just as predicted by a wide range of models for SN Ia explosions.