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Sample records for selection negativity sn

  1. Negative heat capacities in central Xe+Sn reactions

    International Nuclear Information System (INIS)

    Le Neindre, N.; Bougault, R.; Gulminelli, F.

    2000-02-01

    In this study the fluctuation method is applied to the 32-50 A.MeV Xe + Sn central collisions detected with the INDRA multidetector. This method based on kinetic energy fluctuations allows the authors to provide information on the liquid gas phase transition in nuclear multifragmentation. In the case of Xe + Sn central reactions a divergence in the total heat capacity is observed. This divergence corresponds to large fluctuations on the detected fragment partitions. A negative heat capacity branch is measured and so tends to confirm the observation of a first order phase transition in heavy-ion collisions. (A.C.)

  2. Unexpected, spontaneous and selective formation of colloidal Pt 3Sn nanoparticles using organometallic Pt and Sn complexes

    KAUST Repository

    Boualleg, Malika; Baudouin, David; Basset, Jean-Marie; Bayard, Franç ois; Candy, Jean Pierre; Jumas, Jean Claude; Veyre, Laurent; Thieuleux, Chloé

    2010-01-01

    The facile and selective synthesis of small crystalline Pt3Sn alloy nanoparticles was performed at room temperature under H2, using a colloidal approach without the use of extra-stabilizing ligands. The Pt 3Sn alloy was found to be obtained

  3. Unexpected, spontaneous and selective formation of colloidal Pt 3Sn nanoparticles using organometallic Pt and Sn complexes

    KAUST Repository

    Boualleg, Malika

    2010-01-01

    The facile and selective synthesis of small crystalline Pt3Sn alloy nanoparticles was performed at room temperature under H2, using a colloidal approach without the use of extra-stabilizing ligands. The Pt 3Sn alloy was found to be obtained spontaneously as the unique phase regardless of the number of tin equivalents introduced. © 2010 The Royal Society of Chemistry.

  4. Sn surface-enriched Pt-Sn bimetallic nanoparticles as a selective and stable catalyst for propane dehydrogenation

    KAUST Repository

    Zhu, Haibo

    2014-12-01

    A new one pot, surfactant-free, synthetic route based on the surface organometallic chemistry (SOMC) concept has been developed for the synthesis of Sn surface-enriched Pt-Sn nanoparticles. Bu3SnH selectively reacts with [Pt]-H formed in situ at the surface of Pt nanoparticles, Pt NPs, obtained by reduction of K2PtCl4 by LiB(C2H5)3H. Chemical analysis, 1H MAS and 13C CP/MAS solid-state NMR as well as two-dimensional double-quantum (DQ) and triple-quantum (TQ) experiments show that organo-tin moieties Sn(n-C4H9) are chemically linked to the surface of Pt NPs to produce, in fine, after removal of most of the n-butyl fragment, bimetallic Pt-Sn nanoparticles. The Sn(n-CH2CH2CH2CH3) groups remaining at the surface are believed to stabilize the as-synthesized Pt-Sn NPs, enabling the bimetallic NPs to be well dispersed in THF. Additionally, the Pt-Sn nanoparticles can be supported on MgAl2O4 during the synthesis of the nanoparticles. Some of the Pt-Sn/MgAl2O4 catalyst thus prepared exhibits high activity in PROX of CO and an extremely high selectivity and stability in propane dehydrogenation to propylene. The enhanced activity in propane dehydrogenation is associated with the high concentration of inactive Sn at the surface of Pt nanoparticles which ”isolates” the active Pt atoms. This conclusion is confirmed by XRD, NMR, TEM, and XPS analysis.

  5. Cu-Sn Bimetallic Catalyst for Selective Aqueous Electroreduction of CO2 to CO

    KAUST Repository

    Sarfraz, Saad

    2016-03-23

    We report a selective and stable electrocatalyst utilizing non-noble metals consisting of Cu and Sn for the efficient and selective reduction of CO2 to CO over a wide potential range. The bimetallic electrode was prepared through the electrodeposition of Sn species on the surface of oxide-derived copper (OD-Cu). The Cu surface, when decorated with an optimal amount of Sn, resulted in a Faradaic efficiency (FE) for CO greater than 90% and a current density of −1.0 mA cm−2 at −0.6 V vs. RHE, compared to the CO FE of 63% and −2.1 mA cm−2 for OD-Cu. Excess Sn on the surface caused H2 evolution with a decreased current density. X-ray diffraction (XRD) suggests the formation of Cu-Sn alloy. Auger electron spectroscopy of the sample surface exhibits zero-valent Cu and Sn after the electrodeposition step. Density functional theory (DFT) calculations show that replacing a single Cu atom with a Sn atom leaves the d-band orbitals mostly unperturbed, signifying no dramatic shifts in the bulk electronic structure. However, the Sn atom discomposes the multi-fold sites on pure Cu, disfavoring the adsorption of H and leaving the adsorption of CO relatively unperturbed. Our catalytic results along with DFT calculations indicate that the presence of Sn on reduced OD-Cu diminishes the hydrogenation capability—i.e., the selectivity towards H2 and HCOOH—while hardly affecting the CO productivity. While the pristine monometallic surfaces (both Cu and Sn) fail to selectively reduce CO2, the Cu-Sn bimetallic electrocatalyst generates a surface that inhibits adsorbed H*, resulting in improved CO FE. This study presents a strategy to provide a low-cost non-noble metals that can be utilized as a highly selective electrocatalyst for the efficient aqueous reduction of CO2.

  6. Pengaruh Negative Framing dan Adverse Selection terhadap Eskalasi Komitmen

    OpenAIRE

    Arimawan, Muhammad Sandi; Sukirno, Sukirno

    2014-01-01

    Penelitian ini dilakukan bertujuan untuk mengetahui: (1) Pengaruh negative framing terhadap eskalasi komitmen, (2) Pengaruh adverse selection terhadap eskalasi komitmen, (3) Pengaruh negative framing dan adverse selection secara bersama-sama terhadap eskalasi komitmen, (4) Pengaruh negative framing terhadap eskalasi komitmen dimoderasi locus of control, (5) Pengaruh adverse selection terhadap eskalasi komitmen dimoderasi locus of control, (6) Pengaruh negative framing dan adverse selection se...

  7. Decay Study for the very Neutron-Rich Sn Nuclides, $^{135-140}$Sn Separated by Selective Laser Ionization

    CERN Multimedia

    2002-01-01

    %IS378 %title\\\\ \\\\ In this investigation, we wish to take advantage of chemically selective laser ionization to separate the very-neutron-rich Sn nuclides and determine their half-lives and delayed-neutron branches (P$_{n}$) using the Mainz $^{3}$He-delayed neutron spectrometer and close-geometry $\\gamma$-ray spectroscopy system. The $\\beta$-decay rates are dependent on a number of nuclear structure factors that may not be well described by models of nuclear structure developed for nuclides near stability. Determination of these decay properties will provide direct experimental data for r-process calculations and test the large number of models of nuclear structure for very-neutron rich Sn nuclides now in print.

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

    Directory of Open Access Journals (Sweden)

    Niuzi Xue

    2017-10-01

    Full Text Available 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.

  9. Selectivity enhancement of indium-doped SnO2 gas sensors

    International Nuclear Information System (INIS)

    Salehi, A.

    2002-01-01

    Indium doping was used to enhance the selectivity of SnO 2 gas sensor. Both indium-doped and undoped SnO 2 gas sensors fabricated with different deposition techniques were investigated. The changes in the sensitivity of the sensors caused by selective gases (hydrogen and wood smoke) ranging from 500 to 3000 ppm were measured at different temperatures from 50 to 300 deg. C. The sensitivity peaks of the samples exhibit different values for selective gases with a response time of approximately 0.5 s. Thermally evaporated indium-doped SnO 2 gas sensor shows a considerable increase in the sensitivity peak of 27% in response to wood smoke, whereas it shows a sensitivity peak of 7% to hydrogen. This is in contrast to the sputter deposited indium-doped SnO 2 gas sensor, which exhibits a much lower sensitivity peak of approximately 2% to hydrogen and wood smoke compared to undoped SnO 2 gas sensors fabricated by chemical vapor deposition and spray pyrolysis. Scanning electron microscopy shows that different deposition techniques result in different porosity of the films. It is observed that the thermally evaporated indium-doped SnO 2 gas sensor shows high porosity, while the sputtered sample exhibits almost no porosity

  10. The selective catalytic reduction of NO with NH3 over a novel Ce-Sn-Ti mixed oxides catalyst: Promotional effect of SnO2

    Science.gov (United States)

    Yu, Ming'e.; Li, Caiting; Zeng, Guangming; Zhou, Yang; Zhang, Xunan; Xie, Yin'e.

    2015-07-01

    A series of novel catalysts (CexSny) for the selective catalytic reduction of NO by NH3 were prepared by the inverse co-precipitation method. The aim of this novel design was to improve the NO removal efficiency of CeTi by the introduction of SnO2. It was found that the Ce-Sn-Ti catalyst was much more active than Ce-Ti and the best Ce:Sn molar ratio was 2:1. Ce2Sn1 possessed a satisfied NO removal efficiency at low temperature (160-280 °C), while over 90% NO removal efficiency maintained in the temperature range of 280-400 °C at the gas hourly space velocity (GHSV) of 50,000 h-1. Besides, Ce2Sn1 kept a stable NO removal efficiency within a wide range of GHSV and a long period of reacting time. Meanwhile, Ce2Sn1 exhibited remarkable resistance to both respectively and simultaneously H2O and SO2 poisoning due to the introduction of SnO2. The promotional effect of SnO2 was studied by N2 adsorption-desorption, X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS) and H2 temperature programmed reduction (H2-TPR) for detail information. The characterization results revealed that the excellent catalytic performance of Ce2Sn1 was associated with the higher specific surface area, larger pore volume and poorer crystallization. Besides, the introduction of SnO2 could result in not only greater conversion of Ce4+ to Ce3+ but also the increase amount of chemisorbed oxygen, which are beneficial to improve the SCR activity. More importantly, a novel peak appearing at lower temperatures through the new redox equilibrium of 2Ce4+ + Sn2+ ↔ 2Ce3+ + Sn4+ and higher total H2 consumption can be obtained by the addition of SnO2. Finally, the possible reaction mechanism of the selective catalytic reduction over Ce2Sn1 was also proposed.

  11. Sn surface-enriched Pt-Sn bimetallic nanoparticles as a selective and stable catalyst for propane dehydrogenation

    KAUST Repository

    Zhu, Haibo; Anjum, Dalaver H.; Wang, Qingxiao; Abou-Hamad, Edy; Emsley, Lyndon; Dong, Hailin; Laveille, Paco; Li, Lidong; Samal, Akshaya Kumar; Basset, Jean-Marie

    2014-01-01

    Sn(n-C4H9) are chemically linked to the surface of Pt NPs to produce, in fine, after removal of most of the n-butyl fragment, bimetallic Pt-Sn nanoparticles. The Sn(n-CH2CH2CH2CH3) groups remaining at the surface are believed to stabilize the as

  12. Synthesis and properties of Li2SnO3/polyaniline nanocomposites as negative electrode material for lithium-ion batteries

    Science.gov (United States)

    Wang, Qiufen; Huang, Ying; Miao, Juan; Zhao, Yang; Wang, Yan

    2012-10-01

    The nanocomposites Li2SnO3/polyaniline (Li2SnO3/PANI) have been synthesized by a micro emulsion polymerization method. The structure, morphology and electrochemical properties of the as-prepared materials are characterized by XRD, FTIR, Raman, XPS, TGA, TEM and electrochemical measurements. Results show that Li2SnO3/PANI nanocomposites are composed of uniform and blocky nano-sized particles (40-50 nm) with clear lattice fringes. Electrochemical measurement suggests that Li2SnO3/PANI exhibits better cycling properties and lower initial irreversible capacities than Li2SnO3 as negative electrodes materials for lithium-ion batteries. At a current density of 60 mA g-1 in the voltage about 0.05-2.0 V, the initial irreversible capacity of Li2SnO3/PANI is 563 mAh g-1 while it is 687.5 mAh g-1 to Li2SnO3. The capacity retained of Li2SnO3/PANI (569.2 mAh g-1) is higher than that of Li2SnO3 (510.2 mAh g-1) after 50 cycles. The PANI in the Li2SnO3/PANI nanocomposites can buffer the released stress caused by the drastic volume variation during the alloying/de-alloying process of Li-Sn.

  13. Synthesis and properties of Li2SnO3/polyaniline nanocomposites as negative electrode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang Qiufen; Huang Ying; Miao Juan; Zhao Yang; Wang Yan

    2012-01-01

    Highlights: ► Li 2 SnO 3 /polyaniline nanocomposite (40–50 nm) was synthesized by micro emulsion polymerization. ► Li 2 SnO 3 /PANI exhibits lower initial irreversible capacities than Li 2 SnO 3 . ► Its capacity retains 569.2 mAh g −1 after 50 cycles. - Abstract: The nanocomposites Li 2 SnO 3 /polyaniline (Li 2 SnO 3 /PANI) have been synthesized by a micro emulsion polymerization method. The structure, morphology and electrochemical properties of the as-prepared materials are characterized by XRD, FTIR, Raman, XPS, TGA, TEM and electrochemical measurements. Results show that Li 2 SnO 3 /PANI nanocomposites are composed of uniform and blocky nano-sized particles (40–50 nm) with clear lattice fringes. Electrochemical measurement suggests that Li 2 SnO 3 /PANI exhibits better cycling properties and lower initial irreversible capacities than Li 2 SnO 3 as negative electrodes materials for lithium-ion batteries. At a current density of 60 mA g −1 in the voltage about 0.05–2.0 V, the initial irreversible capacity of Li 2 SnO 3 /PANI is 563 mAh g −1 while it is 687.5 mAh g −1 to Li 2 SnO 3 . The capacity retained of Li 2 SnO 3 /PANI (569.2 mAh g −1 ) is higher than that of Li 2 SnO 3 (510.2 mAh g −1 ) after 50 cycles. The PANI in the Li 2 SnO 3 /PANI nanocomposites can buffer the released stress caused by the drastic volume variation during the alloying/de-alloying process of Li–Sn.

  14. Densely Packed, Ultra Small SnO Nanoparticles for Enhanced Activity and Selectivity in Electrochemical CO2 Reduction.

    Science.gov (United States)

    Gu, Jun; Héroguel, Florent; Luterbacher, Jeremy; Hu, Xile

    2018-03-05

    Controlling the selectivity in electrochemical CO 2 reduction is an unsolved challenge. While tin (Sn) has emerged as a promising non-precious catalyst for CO 2 electroreduction, most Sn-based catalysts produce formate as the major product, which is less desirable than CO in terms of separation and further use. Tin monoxide (SnO) nanoparticles supported on carbon black were synthesized and assembled and their application in CO 2 reduction was studied. Remarkably high selectivity and partial current densities for CO formation were obtained using these SnO nanoparticles compared to other Sn catalysts. The high activity is attributed to the ultra-small size of the nanoparticles (2.6 nm), while the high selectivity is attributed to a local pH effect arising from the dense packing of nanoparticles in the conductive carbon black matrix. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Selective Hydrogenation of m-Dinitrobenzene to m-Nitroaniline over Ru-SnOx/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Haiyang Cheng

    2014-07-01

    Full Text Available Series catalysts of Ru-SnOx/Al2O3 with varying SnOx loading of 0–3 wt% were prepared, and their catalytic activity and selectivity have been discussed and compared for the selective hydrogenation of m-dinitrobenzene (m-DNB to m-nitroaniline (m-NAN. The Ru-SnOx/Al2O3 catalysts were characterized by X-ray powder diffraction (XRD, X-ray photoelectron spectroscopy (XPS, transmission electron microscopy (TEM and hydrogen temperature-programmed reduction (H2-TPR and desorption (H2-TPD. Under the modification of SnOx, the reaction activity increased obviously, and the best selectivity to m-NAN reached above 97% at the complete conversion of m-DNB. With the increasing of the SnOx loading, the amount of active hydrogen adsorption on the surface of the catalyst increased according to the H2-TPD analysis, and the electron transferred from Ru to SnOx species, as determined by XPS, inducing an electron-deficient Ru, which is a benefit for the absorption of the nitro group. Therefore, the reaction rate and product selectivity were greatly enhanced. Moreover, the Ru-SnOx/Al2O3 catalyst presented high stability: it could be recycled four times without any loss in activity and selectivity.

  16. Ni–Sn-Supported ZrO2 Catalysts Modified by Indium for Selective CO2 Hydrogenation to Methanol

    KAUST Repository

    Hengne, Amol Mahalingappa

    2018-04-02

    Ni and NiSn supported on zirconia (ZrO2) and on indium (In)-incorporated zirconia (InZrO2) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO2 to methanol in a fixed-bed isothermal flow reactor at 250 °C. The mono-metallic Ni (5%Ni/ZrO2) catalysts showed a very high selectivity for methane (99%) during CO2 hydrogenation. Introduction of Sn to this material with the following formulation 5Ni5Sn/ZrO2 (5% Ni-5% Sn/ZrO2) showed the rate of methanol formation to be 0.0417 μmol/(gcat·s) with 54% selectivity. Furthermore, the combination NiSn supported on InZrO2 (5Ni5Sn/10InZrO2) exhibited a rate of methanol formation 10 times higher than that on 5Ni/ZrO2 (0.1043 μmol/(gcat·s)) with 99% selectivity for methanol. All of these catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy, CO2-temperature-programmed desorption, and density functional theory (DFT) studies. Addition of Sn to Ni catalysts resulted in the formation of a NiSn alloy. The NiSn alloy particle size was kept in the range of 10–15 nm, which was evidenced by HRTEM study. DFT analysis was carried out to identify the surface composition as well as the structural location of each element on the surface in three compositions investigated, namely, Ni28Sn27, Ni18Sn37, and Ni37Sn18 bimetallic nanoclusters, and results were in agreement with the STEM and electron energy-loss spectroscopy results. Also, the introduction of “Sn” and “In” helped improve the reducibility of Ni oxide and the basic strength of catalysts. Considerable details of the catalytic and structural properties of the Ni, NiSn, and NiSnIn catalyst systems were elucidated. These observations were decisive for achieving a highly efficient formation rate of methanol via CO2 by the H2 reduction process with high methanol selectivity.

  17. Perceived social pressure not to experience negative emotion is linked to selective attention for negative information.

    Science.gov (United States)

    Bastian, Brock; Pe, Madeline Lee; Kuppens, Peter

    2017-02-01

    Social norms and values may be important predictors of how people engage with and regulate their negative emotional experiences. Previous research has shown that social expectancies (the perceived social pressure not to feel negative emotion (NE)) exacerbate feelings of sadness. In the current research, we examined whether social expectancies may be linked to how people process emotional information. Using a modified classical flanker task involving emotional rather than non-emotional stimuli, we found that, for those who experienced low levels of NE, social expectancies were linked to the selective avoidance of negative emotional information. Those who experienced high levels of NE did not show a selective avoidance of negative emotional information. The findings suggest that, for people who experience many NEs, social expectancies may lead to discrepancies between how they think they ought to feel and the kind of emotional information they pay attention to.

  18. Synthesis and properties of Li{sub 2}SnO{sub 3}/polyaniline nanocomposites as negative electrode material for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qiufen [School of Science, Northwestern Polytechnical University, Xi' an 710129 (China); School of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Huang Ying, E-mail: yingh@nwpu.edu.cn [School of Science, Northwestern Polytechnical University, Xi' an 710129 (China); Miao Juan [School of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Zhao Yang; Wang Yan [School of Science, Northwestern Polytechnical University, Xi' an 710129 (China)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Li{sub 2}SnO{sub 3}/polyaniline nanocomposite (40-50 nm) was synthesized by micro emulsion polymerization. Black-Right-Pointing-Pointer Li{sub 2}SnO{sub 3}/PANI exhibits lower initial irreversible capacities than Li{sub 2}SnO{sub 3}. Black-Right-Pointing-Pointer Its capacity retains 569.2 mAh g{sup -1} after 50 cycles. - Abstract: The nanocomposites Li{sub 2}SnO{sub 3}/polyaniline (Li{sub 2}SnO{sub 3}/PANI) have been synthesized by a micro emulsion polymerization method. The structure, morphology and electrochemical properties of the as-prepared materials are characterized by XRD, FTIR, Raman, XPS, TGA, TEM and electrochemical measurements. Results show that Li{sub 2}SnO{sub 3}/PANI nanocomposites are composed of uniform and blocky nano-sized particles (40-50 nm) with clear lattice fringes. Electrochemical measurement suggests that Li{sub 2}SnO{sub 3}/PANI exhibits better cycling properties and lower initial irreversible capacities than Li{sub 2}SnO{sub 3} as negative electrodes materials for lithium-ion batteries. At a current density of 60 mA g{sup -1} in the voltage about 0.05-2.0 V, the initial irreversible capacity of Li{sub 2}SnO{sub 3}/PANI is 563 mAh g{sup -1} while it is 687.5 mAh g{sup -1} to Li{sub 2}SnO{sub 3}. The capacity retained of Li{sub 2}SnO{sub 3}/PANI (569.2 mAh g{sup -1}) is higher than that of Li{sub 2}SnO{sub 3} (510.2 mAh g{sup -1}) after 50 cycles. The PANI in the Li{sub 2}SnO{sub 3}/PANI nanocomposites can buffer the released stress caused by the drastic volume variation during the alloying/de-alloying process of Li-Sn.

  19. Manufacturing Feasibility and Forming Properties of Cu-4Sn in Selective Laser Melting.

    Science.gov (United States)

    Mao, Zhongfa; Zhang, David Z; Wei, Peitang; Zhang, Kaifei

    2017-03-24

    Copper alloys, combined with selective laser melting (SLM) technology, have attracted increasing attention in aerospace engineering, automobile, and medical fields. However, there are some difficulties in SLM forming owing to low laser absorption and excellent thermal conductivity. It is, therefore, necessary to explore a copper alloy in SLM. In this research, manufacturing feasibility and forming properties of Cu-4Sn in SLM were investigated through a systematic experimental approach. Single-track experiments were used to narrow down processing parameter windows. A Greco-Latin square design with orthogonal parameter arrays was employed to control forming qualities of specimens. Analysis of variance was applied to establish statistical relationships, which described the effects of different processing parameters (i.e., laser power, scanning speed, and hatch space) on relative density (RD) and Vickers hardness of specimens. It was found that Cu-4Sn specimens were successfully manufactured by SLM for the first time and both its RD and Vickers hardness were mainly determined by the laser power. The maximum value of RD exceeded 93% theoretical density and the maximum value of Vickers hardness reached 118 HV 0.3/5. The best tensile strength of 316-320 MPa is inferior to that of pressure-processed Cu-4Sn and can be improved further by reducing defects.

  20. Pengaruh Adverse Selection dan Negative Framing pada Kecenderungan Eskalasi Komitmen

    OpenAIRE

    Gede Wira Kusuma; Ari Puspa Sari

    2017-01-01

    Eskalasi komitmen merupakan suatu pengambilan keputusan untuk meningkatkan atau memperluas komitmen terhadap suatu proyek atau investasi tertentu meskipun proyek atau investasi tersebut mengindikasikan kegagalan. Penelitian ini bertujuan untuk mendapatkan bukti empiris dari pengaruh adverse selection dan pengaruh negative framing pada kecenderungan eskalasi komitmen. Penelitian ini menggunakan desain eksperimen faktorial 2 x 2 dengan instrumen berupa kasus. Partisipan dalam penelitian ini ad...

  1. NegGOA: negative GO annotations selection using ontology structure.

    Science.gov (United States)

    Fu, Guangyuan; Wang, Jun; Yang, Bo; Yu, Guoxian

    2016-10-01

    Predicting the biological functions of proteins is one of the key challenges in the post-genomic era. Computational models have demonstrated the utility of applying machine learning methods to predict protein function. Most prediction methods explicitly require a set of negative examples-proteins that are known not carrying out a particular function. However, Gene Ontology (GO) almost always only provides the knowledge that proteins carry out a particular function, and functional annotations of proteins are incomplete. GO structurally organizes more than tens of thousands GO terms and a protein is annotated with several (or dozens) of these terms. For these reasons, the negative examples of a protein can greatly help distinguishing true positive examples of the protein from such a large candidate GO space. In this paper, we present a novel approach (called NegGOA) to select negative examples. Specifically, NegGOA takes advantage of the ontology structure, available annotations and potentiality of additional annotations of a protein to choose negative examples of the protein. We compare NegGOA with other negative examples selection algorithms and find that NegGOA produces much fewer false negatives than them. We incorporate the selected negative examples into an efficient function prediction model to predict the functions of proteins in Yeast, Human, Mouse and Fly. NegGOA also demonstrates improved accuracy than these comparing algorithms across various evaluation metrics. In addition, NegGOA is less suffered from incomplete annotations of proteins than these comparing methods. The Matlab and R codes are available at https://sites.google.com/site/guoxian85/neggoa gxyu@swu.edu.cn Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Napping and the Selective Consolidation of Negative Aspects of Scenes

    Science.gov (United States)

    Payne, Jessica D.; Kensinger, Elizabeth A.; Wamsley, Erin; Spreng, R. Nathan; Alger, Sara; Gibler, Kyle; Schacter, Daniel L.; Stickgold, Robert

    2018-01-01

    After information is encoded into memory, it undergoes an offline period of consolidation that occurs optimally during sleep. The consolidation process not only solidifies memories, but also selectively preserves aspects of experience that are emotionally salient and relevant for future use. Here, we provide evidence that an afternoon nap is sufficient to trigger preferential memory for emotional information contained in complex scenes. Selective memory for negative emotional information was enhanced after a nap compared to wakefulness in two control conditions designed to carefully address interference and time-of-day confounds. Although prior evidence has connected negative emotional memory formation to rapid eye movement (REM) sleep physiology, we found that non-REM delta activity and the amount of slow wave sleep (SWS) in the nap were robustly related to the selective consolidation of negative information. These findings suggest that the mechanisms underlying memory consolidation benefits associated with napping and nighttime sleep are not always the same. Finally, we provide preliminary evidence that the magnitude of the emotional memory benefit conferred by sleep is equivalent following a nap and a full night of sleep, suggesting that selective emotional remembering can be economically achieved by taking a nap. PMID:25706830

  3. Selective growth of Ge1- x Sn x epitaxial layer on patterned SiO2/Si substrate by metal-organic chemical vapor deposition

    Science.gov (United States)

    Takeuchi, Wakana; Washizu, Tomoya; Ike, Shinichi; Nakatsuka, Osamu; Zaima, Shigeaki

    2018-01-01

    We have investigated the selective growth of a Ge1- x Sn x epitaxial layer on a line/space-patterned SiO2/Si substrate by metal-organic chemical vapor deposition. We examined the behavior of a Sn precursor of tributyl(vinyl)tin (TBVSn) during the growth on Si and SiO2 substrates and investigated the effect of the Sn precursor on the selective growth. The selective growth of the Ge1- x Sn x epitaxial layer was performed under various total pressures and growth temperatures of 300 and 350 °C. The selective growth of the Ge1- x Sn x epitaxial layer on the patterned Si region is achieved at a low total pressure without Ge1- x Sn x growth on the SiO2 region. In addition, we found that the Sn content in the Ge1- x Sn x epitaxial layer increases with width of the SiO2 region for a fixed Si width even with low total pressure. To control the Sn content in the selective growth of the Ge1- x Sn x epitaxial layer, it is important to suppress the decomposition and migration of Sn and Ge precursors.

  4. Pengaruh Adverse Selection dan Negative Framing pada Kecenderungan Eskalasi Komitmen

    Directory of Open Access Journals (Sweden)

    Gede Wira Kusuma

    2017-02-01

    Full Text Available Escalation of commitment is a decision to increase or expand the commitment to a project or a particular investment even though the investment project or indicate failure. This research has the objective to obtain empirical evidence of the effect of adverse selection and negative framing effect on the escalation of commitment tendency. Experimental design used of this research is 2 x 2 factorial design with the instrument in the form of cases. Participants in this research were Magister ofAccounting and Magister of Management students, as a proxy manager chosen by purposive sampling technique as much as 196 participants. This research uses of two ways ANOVA analysis techniques. This research proves that adverse selection and negative framing have an influence on the propensity of escalation of commitment.

  5. Detecting negative selection on recurrent mutations using gene genealogy

    Science.gov (United States)

    2013-01-01

    Background Whether or not a mutant allele in a population is under selection is an important issue in population genetics, and various neutrality tests have been invented so far to detect selection. However, detection of negative selection has been notoriously difficult, partly because negatively selected alleles are usually rare in the population and have little impact on either population dynamics or the shape of the gene genealogy. Recently, through studies of genetic disorders and genome-wide analyses, many structural variations were shown to occur recurrently in the population. Such “recurrent mutations” might be revealed as deleterious by exploiting the signal of negative selection in the gene genealogy enhanced by their recurrence. Results Motivated by the above idea, we devised two new test statistics. One is the total number of mutants at a recurrently mutating locus among sampled sequences, which is tested conditionally on the number of forward mutations mapped on the sequence genealogy. The other is the size of the most common class of identical-by-descent mutants in the sample, again tested conditionally on the number of forward mutations mapped on the sequence genealogy. To examine the performance of these two tests, we simulated recurrently mutated loci each flanked by sites with neutral single nucleotide polymorphisms (SNPs), with no recombination. Using neutral recurrent mutations as null models, we attempted to detect deleterious recurrent mutations. Our analyses demonstrated high powers of our new tests under constant population size, as well as their moderate power to detect selection in expanding populations. We also devised a new maximum parsimony algorithm that, given the states of the sampled sequences at a recurrently mutating locus and an incompletely resolved genealogy, enumerates mutation histories with a minimum number of mutations while partially resolving genealogical relationships when necessary. Conclusions With their

  6. S2SA preconditioning for the Sn equations with strictly non negative spatial discretization

    International Nuclear Information System (INIS)

    Bruss, D. E.; Morel, J. E.; Ragusa, J. C.

    2013-01-01

    Preconditioners based upon sweeps and diffusion-synthetic acceleration have been constructed and applied to the zeroth and first spatial moments of the 1-D S n transport equation using a strictly non negative nonlinear spatial closure. Linear and nonlinear preconditioners have been analyzed. The effectiveness of various combinations of these preconditioners are compared. In one dimension, nonlinear sweep preconditioning is shown to be superior to linear sweep preconditioning, and DSA preconditioning using nonlinear sweeps in conjunction with a linear diffusion equation is found to be essentially equivalent to nonlinear sweeps in conjunction with a nonlinear diffusion equation. The ability to use a linear diffusion equation has important implications for preconditioning the S n equations with a strictly non negative spatial discretization in multiple dimensions. (authors)

  7. Shape Engineering Driven by Selective Growth of SnO2 on Doped Ga2O3 Nanowires.

    Science.gov (United States)

    Alonso-Orts, Manuel; Sánchez, Ana M; Hindmarsh, Steven A; López, Iñaki; Nogales, Emilio; Piqueras, Javier; Méndez, Bianchi

    2017-01-11

    Tailoring the shape of complex nanostructures requires control of the growth process. In this work, we report on the selective growth of nanostructured tin oxide on gallium oxide nanowires leading to the formation of SnO 2 /Ga 2 O 3 complex nanostructures. Ga 2 O 3 nanowires decorated with either crossing SnO 2 nanowires or SnO 2 particles have been obtained in a single step treatment by thermal evaporation. The reason for this dual behavior is related to the growth direction of trunk Ga 2 O 3 nanowires. Ga 2 O 3 nanowires grown along the [001] direction favor the formation of crossing SnO 2 nanowires. Alternatively, SnO 2 forms rhombohedral particles on [110] Ga 2 O 3 nanowires leading to skewer-like structures. These complex oxide structures were grown by a catalyst-free vapor-solid process. When pure Ga and tin oxide were used as source materials and compacted powders of Ga 2 O 3 acted as substrates, [110] Ga 2 O 3 nanowires grow preferentially. High-resolution transmission electron microscopy analysis reveals epitaxial relationship lattice matching between the Ga 2 O 3 axis and SnO 2 particles, forming skewer-like structures. The addition of chromium oxide to the source materials modifies the growth direction of the trunk Ga 2 O 3 nanowires, growing along the [001], with crossing SnO 2 wires. The SnO 2 /Ga 2 O 3 junctions does not meet the lattice matching condition, forming a grain boundary. The electronic and optical properties have been studied by XPS and CL with high spatial resolution, enabling us to get both local chemical and electronic information on the surface in both type of structures. The results will allow tuning optical and electronic properties of oxide complex nanostructures locally as a function of the orientation. In particular, we report a dependence of the visible CL emission of SnO 2 on its particular shape. Orange emission dominates in SnO 2 /Ga 2 O 3 crossing wires while green-blue emission is observed in SnO 2 particles attached to Ga 2

  8. Selection of a cryostabilized Nb3Sn conductor cooling system for the large coil program

    International Nuclear Information System (INIS)

    Chi, J.W.H.; Murphy, J.H.; Jones, C.K.

    1977-01-01

    The Large Coil Project (LCP) is a program to design, fabricate and test relatively large superconducting toroidal field coils for tokamak fusion reactor applications. Some basic requirements that affect the conductor design are cryostabilization, 8 tesla peak magnetic field, and a specified maximum refrigeration load. The engineering considerations that led to the selection of a forced flow supercritical helium-cooled cable conductor are described. Comparisons of forced flow supercritical helium cooled cable conductors with pool boiling cooled monolithic conductors were made with regard to a number of factors such as the thermal capacity of the coolant, the thermal design margins, propensity for conductor normalization, predictability of the thermal-flow performance, controllability of the cooling conditions, etc. It was concluded that, although there exists a number of design uncertainties and engineering problems, forced flow supercritical helium cooled conductors can provide a far more reliable coil design than the pool boiling monolithic concept. The design of a cryostabilized Nb 3 Sn hollow cabled conductor involved detailed considerations of the need for fully transposed conductor strands, the nonuniform void and helium flow distributions, heat transfer from the twisted conductor strands, and helium flow rate and pump work requirements. The uncertainties in the design are discussed and the specifications of a reference Nb 3 Sn conductor concept that meets the design requirements and constraints are presented

  9. Positive-negative-selection-mediated gene targeting in rice

    Directory of Open Access Journals (Sweden)

    Zenpei eShimatani

    2015-01-01

    Full Text Available Gene targeting (GT refers to the designed modification of genomic sequence(s through homologous recombination (HR. GT is a powerful tool both for the study of gene function and for molecular breeding. However, in transformation of higher plants, non-homologous end joining (NHEJ occurs overwhelmingly in somatic cells, masking HR-mediated GT. Positive-negative selection (PNS is an approach for finding HR-mediated GT events because it can eliminate NHEJ effectively by expression of a negative-selection marker gene. In rice—a major crop worldwide—reproducible PNS-mediated GT of endogenous genes has now been successfully achieved. The procedure is based on strong PNS using diphtheria toxin A-fragment as a negative marker, and has succeeded in the directed modification of several endogenous rice genes in various ways. In addition to gene knock-outs and knock-ins, a nucleotide substitution in a target gene was also achieved recently. This review presents a summary of the development of the rice PNS system, highlighting its advantages. Different types of gene modification and gene editing aimed at developing new plant breeding technology (NPBT based on PNS are discussed.

  10. Shape-selective synthesis of Sn(MoO4)2 nanomaterials for catalysis and supercapacitor applications.

    Science.gov (United States)

    Sakthikumar, K; Ede, Sivasankara Rao; Mishra, Soumyaranjan; Kundu, Subrata

    2016-06-07

    Size and shape-selective Sn(MoO4)2 nanomaterials have been synthesized for the first time using a simple hydrothermal route by the reaction of Sn(ii) chloride salt with sodium molybdate in CTAB micellar media under stirring at 60 °C temperature for about three hours. Needle-like and flake-like Sn(MoO4)2 nanomaterials were synthesized by optimizing the CTAB to metal salt molar ratio and by controlling other reaction parameters. The eventual diameter and length of the nanoneedles are ∼100 ± 10 nm and ∼850 ± 100 nm respectively. The average diameter of the flakes is ∼250 ± 50 nm. The synthesized Sn(MoO4)2 nanomaterials can be used in two potential applications, namely, catalytic reduction of nitroarenes and as an anodic material in electrochemical supercapacitors. From the catalysis study, it was observed that the Sn(MoO4)2 nanomaterials could act as a potential catalyst for the successful photochemical reduction of nitroarenes into their respective aminoarenes within a short reaction time. From the supercapacitor study, it was observed that the Sn(MoO4)2 nanomaterials of different shapes show different specific capacitance (Cs) values and the highest Cs value was observed for Sn(MoO4)2 nanomaterials having a flake-like morphology. The highest Cs value observed was 109 F g(-1) at a scan rate of 5 mV s(-1) for the flake-like Sn(MoO4)2 nanomaterials. The capacitor shows an excellent long cycle life along with 70% retention of the Cs value, even after 4000 consecutive cycles at a current density of 8 mA cm(-2). Other than the applications in catalysis and supercapacitors, the synthesized nanomaterials can find further applications in photoluminescence, sensor and other energy-related devices.

  11. Negative-Ion source for mass selective photodetachment photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Kaesmaier, R.; Baemann, C.; Drechsler, G.; Boesl, U.

    1995-01-01

    We have designed and constructed a negative ion source for mass spectrometry and mass selective photodetachement photoelectron spectroscopy. The characteristics of the source are high anion densities and a large variety of accessible systems. Thus, mass spectra and photoelectron spectra of large unvolatile moelcules (biomolecules), of metal-organic compounds and of molecule water clusters, especially mentioned in this article, have been measured. Combining mass spectrometry, photoelectron spectroscopy (PES) and high resolution ZEKE (zero kinetic energy)-PES (1) should make the apparatus to an ideal diagnostic tool for structural assignment

  12. Study on the Selective Laser Melting of CuSn10 Powder

    Directory of Open Access Journals (Sweden)

    Chengyang Deng

    2018-04-01

    Full Text Available The selective laser melting of tin bronze (CuSn10 powder was performed with a laser energy density intensity level at 210, 220, and 230 J/mm2. The composition was homogeneous with almost all tin dissolved into the matrix. The grain size of the obtained alpha copper phase was around 5 μm. The best properties were achieved at 220 J/mm2 laser energy density with a density of 8.82 g/cm3, hardness of 78.2 HRB (Rockwell Hardness measured on the B scale, yield strength of 399 MPa, tensile strength of 490 MPa, and an elongation that reached 19%. “Balling effect” appeared and resulted into a decrease of properties when the laser energy density increased to 230 J/mm2.

  13. Study on the Selective Laser Melting of CuSn10 Powder.

    Science.gov (United States)

    Deng, Chengyang; Kang, Jinwu; Feng, Tao; Feng, Yunlong; Wang, Xiang; Wu, Pengyue

    2018-04-17

    The selective laser melting of tin bronze (CuSn 10 ) powder was performed with a laser energy density intensity level at 210, 220, and 230 J/mm². The composition was homogeneous with almost all tin dissolved into the matrix. The grain size of the obtained alpha copper phase was around 5 μm. The best properties were achieved at 220 J/mm² laser energy density with a density of 8.82 g/cm³, hardness of 78.2 HRB (Rockwell Hardness measured on the B scale), yield strength of 399 MPa, tensile strength of 490 MPa, and an elongation that reached 19%. “Balling effect” appeared and resulted into a decrease of properties when the laser energy density increased to 230 J/mm².

  14. Selective Hydrogenation of Biomass-derived Furfural over Supported Ni3Sn2 Alloy: Role of Supports

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2016-03-01

    Full Text Available A highly active and selective hydrogenation of biomass-derived furfural into furfuryl alcohol was achieved using supported single phase Ni3Sn2 alloy catalysts. Various supports such as active carbon (AC, g-Al2O3, Al(OH3, ZnO, TiO2, ZrO2, MgO, Li-TN, and SiO2 have been employed in order to understand the role of the support on the formation of Ni3Sn2 alloy phase and its catalytic performance. Supported Ni3Sn2 alloy catalysts were synthesised via a simple hydrothermal treatment of the mixture of aqueous solution of nickel chloride hexahydrate and ethanol solution of tin(II chloride dihydrate in presence of ethylene glycol at 423 K for 24 h followed by H2 treatment at 673 K for 1.5 h, then characterised by using ICP-AES, XRD, H2- and N2-adsorption. XRD profiles of samples showed that the Ni3Sn2 alloy phases are readily formed during hydrothermal processes and become clearly observed at 2θ = 43-44o after H2 treatment. The presence of Ni3Sn2 alloy species that dispersed on the supports is believed to play a key role in highly active and selective hydrogenation of biomass-derived furfural towards furfuryl alcohol. Ni3Sn2 on TiO2 and ZnO supports exhibited much lower reaction temperature to achieved >99% yield of furfuryl alcohol product compared with other supports. The effects of loading amount of Ni-Sn, reaction conditions (temperature and time profile on the activity and selectivity towards the desired product are systematically discussed. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 31st December 2015; Accepted: 5th January 2016 How to Cite: Rodiansono, R., Astuti, M.D., Khairi, S., Shimazu, S. (2016. Selective Hydrogenation of Biomass-derived Furfural over Supported Ni3Sn2 Alloy: Role of Supports. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 1-9. (doi:10.9767/bcrec.11.1.393.1-9 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.393.1-9

  15. Scanning pattern angle effect on the resulting properties of selective laser sintered monolayers of Cu-Sn-Ni powder

    Science.gov (United States)

    Sabelle, Matías; Walczak, Magdalena; Ramos-Grez, Jorge

    2018-01-01

    Laser-based layer manufacturing of metals, also known as additive manufacturing, is a growing research field of academic and industrial interest. However, in the associated laser-driven processes (i.e. selective laser sintering (SLS) or melting (SLM)), optimization of some parameters has not been fully explored. This research aims at determining how the angle of laser scanning pattern (i.e. build orientation) in SLS affects the mechanical properties and structure of an individual Cu-Sn-Ni alloy metallic layer sintered in the process. Experiments consist in varying the angle of the scanning pattern (0°, 30°, 45° 60° and 90° relative to the transverse dimension of the piece), at constant scanning speed and laser beam power, producing specimens of different thicknesses. A noticeable effect of the scan angle on the mechanical strength and degree of densification of the sintered specimens is found. Thickness of the resulting monolayer correlates negatively with increasing scan angle, whereas relative density correlates positively. A minimum porosity and maximum UTS are found at the angle of 60°. It is concluded that angle of the scanning pattern angle plays a significant role in SLS of metallic monolayers.

  16. Identity negative priming: a phenomenon of perception, recognition or selection?

    Directory of Open Access Journals (Sweden)

    Hecke Schrobsdorff

    Full Text Available The present study addresses the problem whether negative priming (NP is due to information processing in perception, recognition or selection. We argue that most NP studies confound priming and perceptual similarity of prime-probe episodes and implement a color-switch paradigm in order to resolve the issue. In a series of three identity negative priming experiments with verbal naming response, we determined when NP and positive priming (PP occur during a trial. The first experiment assessed the impact of target color on priming effects. It consisted of two blocks, each with a different fixed target color. With respect to target color no differential priming effects were found. In Experiment 2 the target color was indicated by a cue for each trial. Here we resolved the confounding of perceptual similarity and priming condition. In trials with coinciding colors for prime and probe, we found priming effects similar to Experiment 1. However, trials with a target color switch showed such effects only in trials with role-reversal (distractor-to-target or target-to-distractor, whereas the positive priming (PP effect in the target-repetition trials disappeared. Finally, Experiment 3 split trial processing into two phases by presenting the trial-wise color cue only after the stimulus objects had been recognized. We found recognition in every priming condition to be faster than in control trials. We were hence led to the conclusion that PP is strongly affected by perception, in contrast to NP which emerges during selection, i.e., the two effects cannot be explained by a single mechanism.

  17. Selective increase of in vivo firing frequencies in DA SN neurons after proteasome inhibition in the ventral midbrain.

    Science.gov (United States)

    Subramaniam, Mahalakshmi; Kern, Beatrice; Vogel, Simone; Klose, Verena; Schneider, Gaby; Roeper, Jochen

    2014-09-01

    The impairment of protein degradation via the ubiquitin-proteasome system (UPS) is present in sporadic Parkinson's disease (PD), and might play a key role in selective degeneration of vulnerable dopamine (DA) neurons in the substantia nigra pars compacta (SN). Further evidence for a causal role of dysfunctional UPS in familial PD comes from mutations in parkin, which results in a loss of function of an E3-ubiquitin-ligase. In a mouse model, genetic inactivation of an essential component of the 26S proteasome lead to widespread neuronal degeneration including DA midbrain neurons and the formation of alpha-synuclein-positive inclusion bodies, another hallmark of PD. Studies using pharmacological UPS inhibition in vivo had more mixed results, varying from extensive degeneration to no loss of DA SN neurons. However, it is currently unknown whether UPS impairment will affect the neurophysiological functions of DA midbrain neurons. To answer this question, we infused a selective proteasome inhibitor into the ventral midbrain in vivo and recorded single DA midbrain neurons 2 weeks after the proteasome challenge. We found a selective increase in the mean in vivo firing frequencies of identified DA SN neurons in anesthetized mice, while those in the ventral tegmental area (VTA) were unaffected. Our results demonstrate that a single-hit UPS inhibition is sufficient to induce a stable and selective hyperexcitability phenotype in surviving DA SN neurons in vivo. This might imply that UPS dysfunction sensitizes DA SN neurons by enhancing 'stressful pacemaking'. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  18. Mechanism of selective recruitment of RNA polymerases II and III to snRNA gene promoters.

    Science.gov (United States)

    Dergai, Oleksandr; Cousin, Pascal; Gouge, Jerome; Satia, Karishma; Praz, Viviane; Kuhlman, Tracy; Lhôte, Philippe; Vannini, Alessandro; Hernandez, Nouria

    2018-05-01

    RNA polymerase II (Pol II) small nuclear RNA (snRNA) promoters and type 3 Pol III promoters have highly similar structures; both contain an interchangeable enhancer and "proximal sequence element" (PSE), which recruits the SNAP complex (SNAPc). The main distinguishing feature is the presence, in the type 3 promoters only, of a TATA box, which determines Pol III specificity. To understand the mechanism by which the absence or presence of a TATA box results in specific Pol recruitment, we examined how SNAPc and general transcription factors required for Pol II or Pol III transcription of SNAPc-dependent genes (i.e., TATA-box-binding protein [TBP], TFIIB, and TFIIA for Pol II transcription and TBP and BRF2 for Pol III transcription) assemble to ensure specific Pol recruitment. TFIIB and BRF2 could each, in a mutually exclusive fashion, be recruited to SNAPc. In contrast, TBP-TFIIB and TBP-BRF2 complexes were not recruited unless a TATA box was present, which allowed selective and efficient recruitment of the TBP-BRF2 complex. Thus, TBP both prevented BRF2 recruitment to Pol II promoters and enhanced BRF2 recruitment to Pol III promoters. On Pol II promoters, TBP recruitment was separate from TFIIB recruitment and enhanced by TFIIA. Our results provide a model for specific Pol recruitment at SNAPc-dependent promoters. © 2018 Dergai et al.; Published by Cold Spring Harbor Laboratory Press.

  19. Ir/Sn dual-reagent catalysis towards highly selective alkylation of ...

    Indian Academy of Sciences (India)

    Wintec

    Organometallic; bimetallic; catalysis; alkylation; benzyl alcohol; iridium, tin. 1. Introduction ... cording to our proposal, the oxidative addition of tin(IV) halides across a ..... 33. 4. Conclusion. In summary, we have demonstrated here an Ir/Sn.

  20. Role of ZrO2 incorporation in the suppression of negative bias illumination-induced instability in Zn-Sn-O thin film transistors

    International Nuclear Information System (INIS)

    Yang, Bong Seob; Oh, Seungha; Lee, Ung Soo; Kim, Yoon Jang; Oh, Myeong Sook; Hwang, Cheol Seong; Kim, Hyeong Joon; Huh, Myung Soo; Jeong, Jae Kyeong

    2011-01-01

    Thin film transistors (TFTs) with In and Ga-free multicomponent Zn-Sn-Zr-O (ZTZO) channel layers were fabricated using the cosputtering approach. The incorporation of ZrO 2 into the Zn-Sn-O (ZTO) films increased the contact resistance, which led to the degradation of the transport properties. In contrast, the threshold voltage shift under negative bias illumination stress (NBIS) was largely improved from -12.5 V (ZTO device) to -4.2 V (ZTZO device). This improvement was attributed to the reduction in the oxygen vacancy defects in the ZTZO film, suggesting that the photoinduced transition from V O to V O 2+ was responsible for the NBIS-induced instability.

  1. Negative Mood Increases Selective Attention to Negatively Valenced Body Parts in Female Adolescents with Anorexia Nervosa.

    Directory of Open Access Journals (Sweden)

    Jennifer Svaldi

    Full Text Available Previous research has yielded evidence of increased attentional processing of negatively valenced body parts in women with anorexia nervosa (AN, especially for those with high depressive symptomatology. The present study extended previous research by implementing an experimental mood manipulation.In a within-subjects design, female adolescents with AN (n = 12 and an age matched female control group (CG; n = 12 were given a negative and a positive mood induction at a one-week interval. After each mood induction, participants underwent a 3-min mirror exposure, while their eye movements were recorded.After the positive mood induction, both AN and CG participants displayed longer and more frequent gazes towards their self-defined most ugly relative to their self-defined most beautiful body part. However, after the negative mood induction, only females with AN were characterized by increased attention to their most ugly compared to their most beautiful body part, while CG participants' attention distribution was balanced. Furthermore, in the negative (but not in the positive mood induction condition gaze frequency and duration towards the most ugly body part was significantly stronger in the AN group relative to the CG.The results emphasize the role of negative mood in the maintenance of pathological information processing of the self-body. This increased body-related negativity-bias during negative mood may lead to the persistence and aggravation of AN patients' body image disturbance.

  2. Fission of Weakly Prolate 119Sn and Weakly Oblate 209Bi Nuclei Induced by 500 and 672 MeV Negative Pions

    International Nuclear Information System (INIS)

    Rana, Mukhtar Ahmed; Sher, Gul; Manzoor, Shahid; Shahzad, M. I.

    2011-01-01

    Fission cross-sections of 119 Sn and 209 Bi induced by negative pions of two energies 500 and 672 MeV were measured using a CR-39 nuclear track detector. Target-detector stacks were exposed to pion beams at the Brookhaven National Laboratory (USA). Measurement results are compared with the corresponding calculations using the computer code CEM95. Agreement between measurements and calculations is fairly good for the 209 Bi target nuclei whereas it is poor for 119 Sn at both investigated energies of 500 and 672 MeV. Fission cross-section results of 119 Sn and 209 Bi are explained using the equilibrium properties of these nuclides including nuclear electric quadrupole moments which determine the shapes of nuclei. A logarithmic dependence of fission cross-section on Z 2 /A is observed for the above-mentioned reactions and a critical limit of Z 2 /A is identified with the value of 30 which divides the curve of σ f versus Z 2 /A into two regimes, one with weak dependence and the other with strong dependence. (nuclear physics)

  3. Fission of Weakly Prolate 119Sn and Weakly Oblate 209Bi Nuclei Induced by 500 and 672 MeV Negative Pions

    Science.gov (United States)

    Mukhtar, Ahmed Rana; Gul, Sher; Shahid, Manzoor; I. Shahzad, M.

    2011-09-01

    Fission cross-sections of 119Sn and 209Bi induced by negative pions of two energies 500 and 672 MeV were measured using a CR-39 nuclear track detector. Target-detector stacks were exposed to pion beams at the Brookhaven National Laboratory (USA). Measurement results are compared with the corresponding calculations using the computer code CEM95. Agreement between measurements and calculations is fairly good for the 209Bi target nuclei whereas it is poor for 119Sn at both investigated energies of 500 and 672 MeV. Fission cross-section results of 119Sn and 209Bi are explained using the equilibrium properties of these nuclides including nuclear electric quadrupole moments which determine the shapes of nuclei. A logarithmic dependence of fission cross-section on Z2/A is observed for the above-mentioned reactions and a critical limit of Z2/A is identified with the value of 30 which divides the curve of σf versus Z2/A into two regimes, one with weak dependence and the other with strong dependence.

  4. Improving the stability and ethanol electro-oxidation activity of Pt catalysts by selectively anchoring Pt particles on carbon-nanotubes-supported-SnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.J.; Wang, J.S.; Zhao, J.H.; Song, C.Y.; Wang, L.C. [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou (China); Guo, X. [Department of Chemistry, Tsinghua University, Beijing (China)

    2012-10-15

    To improve the stability and activity of Pt catalysts for ethanol electro-oxidation, Pt nanoparticles were selectively deposited on carbon-nanotubes (CNTs)-supported-SnO{sub 2} to prepare Pt/SnO{sub 2}/CNTs and Pt/CNTs was prepared by impregnation method for reference study. X-ray diffraction (XRD) was used to confirm the crystalline structures of Pt/SnO{sub 2}/CNTs and Pt/CNTs. The stabilities of Pt/SnO{sub 2}/CNTs and Pt/CNTs were compared by analyzing the Pt size increase amplitude using transmission electron microscopy (TEM) images recorded before and after cyclic voltammetry (CV) sweeping. The results showed that the Pt size increase amplitude is evidently smaller for Pt/SnO{sub 2}/CNTs, indicating the higher stability of Pt/SnO{sub 2}/CNTs. Although both catalysts exhibit degradation of electrochemical active surface area (EAS) after CV sweeping, the EAS degradation for the former is lower, further confirming the higher stability of Pt/SnO{sub 2}/CNTs. CV and potentiostatic current-time curves were recorded for ethanol electro-oxidation on both catalysts before and after CV sweeping and the results showed that the mass specific activity of Pt/CNTs increases more than that of Pt/SnO{sub 2}/CNTs, indicating that Pt/CNTs experiences more severe evolution and is less stable. The calculated area specific activity of Pt/SnO{sub 2}/CNTs is larger than that of Pt/CNTs, indicating SnO{sub 2} can co-catalyze Pt due to plenty of interfaces between SnO{sub 2} and Pt. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Modelling the negative effects of landscape fragmentation on habitat selection

    NARCIS (Netherlands)

    Langevelde, van F.

    2015-01-01

    Landscape fragmentation constrains movement of animals between habitat patches. Fragmentation may, therefore, limit the possibilities to explore and select the best habitat patches, and some animals may have to cope with low-quality patches due to these movement constraints. If so, these individuals

  6. Determination of Cr, Cd, Sn, and Pb in Selected Herbal Products Available in Philippine Markets

    Directory of Open Access Journals (Sweden)

    Joan S. De Vera

    2017-12-01

    Full Text Available The growing popularity of herbal products in the Philippines makes it imperative to monitor and ensure safety of consumers from metal contaminants. In this study, trace concentrations of Cr, Cd, Sn, and Pb in herbal products were simultaneously measured using a microwaveassisted digestion as sample pre-treatment and inductively coupled plasma mass spectrometry (ICP-MS for elemental detection. Using the optimized method, recoveries of ERM CD281, the primary cer t i f ied reference material (CRM used, were found to be between 80-89%, and the method detection limits (MDL for Cr, Cd, Sn, and Pb were 0.15, 0.07, 0.3, and 0.14 μg/L, respectively. The linear ranges for Cr and other elements (Cd, Sn, and Pb were 0.01-500 and 0.01-50 μg/L, respectively. All correlation coeff icients were 0.9999 or better. Most of the products tested had measurable trace metal concentrations, which were below the suggested maximum limits in herbal products. However, one product derived from mangosteen exceeded the limit for Cd (0.42 mg/kg. Subsequent analysis of metal content in tea infusions showed that only a small fraction of metals may leach out, suggesting that consumption of tea infusions pose lesser risks. The order of abundance of metals found in herbal products was Cr>Pb>Cd>Sn. The variability of metal concentrations in herbal products underlines the fact that many plant ingredients are susceptible to contamination, and quality control during processing must be improved to minimize the possibility of contamination. The results of this study suggest that vigilant monitoring of herbal products is imperative to avoid exposure to trace metal contamination.

  7. Performance and selectivity of PtxSn/C electro-catalysts for ethanol oxidation prepared by reduction with different formic acid concentrations

    International Nuclear Information System (INIS)

    Zignani, Sabrina C.; Baglio, Vincenzo; Linares, José J.; Monforte, Giuseppe; Gonzalez, Ernesto R.; Aricò, Antonino S.

    2012-01-01

    Carbon supported Pt–Sn catalysts were prepared by reduction of Pt and Sn precursors with formic acid and characterized in terms of structure, morphology and surface properties. The electrocatalytic activity for ethanol oxidation was studied in a direct ethanol fuel cell (DEFC) at 70 °C and 90 °C. Electrochemical and physico-chemical data indicated that a proper balance of Pt and Sn species in the near surface region was necessary to maximize the reaction rate. The best atomic surface composition, in terms of electrochemical performance, was Pt:Sn 65:35 corresponding to a bulk composition 75:25 namely Pt 3 Sn 1 /C. The reaction products of ethanol electro-oxidation in single cell and their distribution as a function of the nature of catalyst were determined. Essentially, acetaldehyde and acetic acid were detected as the main reaction products; whereas, a lower content of CO 2 was formed. The selectivity toward acetic acid vs. acetaldehyde increased with the increase of the Sn content and decreased by decreasing the concentration of the reducing agent used in the catalyst preparation. According to the recent literature, these results have been interpreted on the basis of ethanol adsorption characteristics and ligand effects occurring for Sn-rich electrocatalysts.

  8. Children Do Show Negative Priming: Further Evidence for Early Development of an Intact Selective Control Mechanism

    Science.gov (United States)

    Frings, Christian; Feix, Silke; Rothig, Ulrike; Bruser, Charlotte; Junge, Miriam

    2007-01-01

    Reactions to stimuli that were shortly before presented as distractors are usually slowed down; this phenomenon is known as negative priming. Negative priming is an accepted index for tapping into selective control mechanisms. Although this effect is well established for adults, it has been claimed that children do not show negative priming.…

  9. Rare Earth Chalcogels NaLnSnS4 (Ln = Y, Gd, Tb) for Selective Adsorption of Volatile Hydrocarbons and Gases

    KAUST Repository

    Edhaim, Fatimah

    2017-06-28

    The synthesis and characterization of the rare earth chalcogenide aerogels NaYSnS4, NaGdSnS4, and NaTbSnS4 is reported. Rare earth metal ions like Y3+, Gd3+, and Tb3+ react with the chalcogenide clusters [SnS4]4– in aqueous formamide solution forming extended polymeric networks by gelation. Aerogels obtained after supercritical drying have BET surface areas of 649 m2·g–1 (NaYSnS4), 479 m2·g–1 (NaGdSnS4), and 354 m2·g–1 (NaTbSnS4). Electron microscopy and physisorption studies reveal that the new materials have pores in the macro (above 50 nm) and meso (2–50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO2 over CH4 or H2. The notable adsorption capacity for toluene (NaYSnS4: 1108 mg·g–1; NaGdSnS4: 921 mg·g–1; and NaTbSnS4: 645 mg·g–1) and high selectivity for gases (CO2/H2: 172 and CO2/CH4: 50 for NaYSnS4, CO2/H2: 155 and CO2/CH4: 37 for NaGdSnS4, and CO2/H2: 75 and CO2/CH4: 28 for NaTbSnS4) indicate potential future use of chalcogels in adsorption-based gas or hydrocarbon separation processes.

  10. Purine salvage in the apicomplexan Sarcocystis neurona, and generation of hypoxanthine-xanthine-guanine phosphoribosyltransferase-deficient clones for positive-negative selection of transgenic parasites.

    Science.gov (United States)

    Dangoudoubiyam, Sriveny; Zhang, Zijing; Howe, Daniel K

    2014-09-01

    Sarcocystis neurona is an apicomplexan parasite that causes severe neurological disease in horses and marine mammals. The Apicomplexa are all obligate intracellular parasites that lack purine biosynthesis pathways and rely on the host cell for their purine requirements. Hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) and adenosine kinase (AK) are key enzymes that function in two complementary purine salvage pathways in apicomplexans. Bioinformatic searches of the S. neurona genome revealed genes encoding HXGPRT, AK and all of the major purine salvage enzymes except purine nucleoside phosphorylase. Wild-type S. neurona were able to grow in the presence of mycophenolic acid (MPA) but were inhibited by 6-thioxanthine (6-TX), suggesting that the pathways involving either HXGPRT or AK are functional in this parasite. Prior work with Toxoplasma gondii demonstrated the utility of HXGPRT as a positive-negative selection marker. To enable the use of HXGPRT in S. neurona, the SnHXGPRT gene sequence was determined and a gene-targeting plasmid was transfected into S. neurona. SnHXGPRT-deficient mutants were selected with 6-TX, and single-cell clones were obtained. These Sn∆HXG parasites were susceptible to MPA and could be complemented using the heterologous T. gondii HXGPRT gene. In summary, S. neurona possesses both purine salvage pathways described in apicomplexans, thus allowing the use of HXGPRT as a positive-negative drug selection marker in this parasite.

  11. Systematic and controllable negative, zero, and positive thermal expansion in cubic Zr(1-x)Sn(x)Mo2O8.

    Science.gov (United States)

    Tallentire, Sarah E; Child, Felicity; Fall, Ian; Vella-Zarb, Liana; Evans, Ivana Radosavljević; Tucker, Matthew G; Keen, David A; Wilson, Claire; Evans, John S O

    2013-08-28

    We describe the synthesis and characterization of a family of materials, Zr1-xSnxMo2O8 (0 thermal expansion coefficient can be systematically varied from negative to zero to positive values. These materials allow tunable expansion in a single phase as opposed to using a composite system. Linear thermal expansion coefficients, αl, ranging from -7.9(2) × 10(-6) to +5.9(2) × 10(-6) K(-1) (12-500 K) can be achieved across the series; contraction and expansion limits are of the same order of magnitude as the expansion of typical ceramics. We also report the various structures and thermal expansion of "cubic" SnMo2O8, and we use time- and temperature-dependent diffraction studies to describe a series of phase transitions between different ordered and disordered states of this material.

  12. Method of generating intense nuclear polarized beams by selective photodetachment of negative ions

    International Nuclear Information System (INIS)

    Hershcovitch, A.

    1986-01-01

    A novel method for production of nuclear polarized negative hydrogen ions by selective neutralization with a laser of negative hydrogen ions in a magnetic field is described. This selectivity is possible since a final state of the neutralized atom, and hence the neutralization energy, depends on its nuclear polarization. The main advantages of this scheme are the availability of multi-ampere negative ion sources and the possibility of neutralizing negative ions with very high efficiency. An assessment of the required laser power indicates that this method is in principle feasible with today's technology

  13. Atomic Layer Deposition of Electron Selective SnOx and ZnO Films on Mixed Halide Perovskite: Compatibility and Performance.

    Science.gov (United States)

    Hultqvist, Adam; Aitola, Kerttu; Sveinbjörnsson, Kári; Saki, Zahra; Larsson, Fredrik; Törndahl, Tobias; Johansson, Erik; Boschloo, Gerrit; Edoff, Marika

    2017-09-06

    The compatibility of atomic layer deposition directly onto the mixed halide perovskite formamidinium lead iodide:methylammonium lead bromide (CH(NH 2 ) 2 , CH 3 NH 3 )Pb(I,Br) 3 (FAPbI 3 :MAPbBr 3 ) perovskite films is investigated by exposing the perovskite films to the full or partial atomic layer deposition processes for the electron selective layer candidates ZnO and SnO x . Exposing the samples to the heat, the vacuum, and even the counter reactant of H 2 O of the atomic layer deposition processes does not appear to alter the perovskite films in terms of crystallinity, but the choice of metal precursor is found to be critical. The Zn precursor Zn(C 2 H 5 ) 2 either by itself or in combination with H 2 O during the ZnO atomic layer deposition (ALD) process is found to enhance the decomposition of the bulk of the perovskite film into PbI 2 without even forming ZnO. In contrast, the Sn precursor Sn(N(CH 3 ) 2 ) 4 does not seem to degrade the bulk of the perovskite film, and conformal SnO x films can successfully be grown on top of it using atomic layer deposition. Using this SnO x film as the electron selective layer in inverted perovskite solar cells results in a lower power conversion efficiency of 3.4% than the 8.4% for the reference devices using phenyl-C 70 -butyric acid methyl ester. However, the devices with SnO x show strong hysteresis and can be pushed to an efficiency of 7.8% after biasing treatments. Still, these cells lacks both open circuit voltage and fill factor compared to the references, especially when thicker SnO x films are used. Upon further investigation, a possible cause of these losses could be that the perovskite/SnO x interface is not ideal and more specifically found to be rich in Sn, O, and halides, which is probably a result of the nucleation during the SnO x growth and which might introduce barriers or alter the band alignment for the transport of charge carriers.

  14. First Principles Investigation of the Mechanical, Thermodynamic and Electronic Properties of FeSn{sub 5} and CoSn{sub 5} Intermetallic Phases under Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wenming; Liu, Jing; Wang, Hong [China Building Materials Academy, Beijing (China); Zhang, Zhenwei [Linyi Academy of Technology Cooperation and Application, Linyi (China); Zhang, Liang [NeoTrident Technology Ltd., Shanghai (China); Bu, Yuxiang [Shandong University, Jinan (China)

    2017-02-15

    For guidance for developing Fe/Co-Sn-based anode materials for lithium-ion batteries, the mechanical, thermodynamic and electronic properties of FeSn{sub 5} and CoSn{sub 5} intermetallic phases under pressures ranging from 0 to 30 GPa have been investigated systematically using first-principles total-energy calculations within the framework of the generalized gradient approximation. The pressure was found to have significant effects on the mechanical, thermodynamic and electronic properties of these compounds. In the selected pressure range, CoSn{sub 5} has a more negative formation enthalpy than FeSn{sub 5}. Based on the calculated elastic constants, the bulk modulus, shear modulus, and Young's modulus were determined via the Viogt-Reuss-Hill averaging scheme. The variations of specific heats at constant volume for FeSn{sub 5} and CoSn{sub 5} in a wide pressure (0 - 30 GPa) and temperature (0 - 1000 K) range are also predicted from phonon density of states calculation. The calculated results suggested that both FeSn{sub 5} and CoSn{sub 5} are mechanically stable at pressure from 0 to 30 GPa. FeSn{sub 5} is dynamically stable at pressure up to, 30 GPa, at least, however, CoSn{sub 5} is dynamically stable no higher than 15 GPa.

  15. Generation of intense polarized beams by selective neutralization of negative ions

    International Nuclear Information System (INIS)

    Hershcovitch, A.I.; Hinds, E.A.

    1983-01-01

    A novel scheme is proposed. This method is based on selective neutralization by laser negative hydrogen ions in a magnetic field. This selectivity is based on the fact that the final state of the neutralized atom depends on nuclear polarization in the magnetic field. A two-scenario approach is to be followed: one in which the resulting neutral atom is in the ground state, and in the other the neutral atom is in the n = 2 level. Limiting factors are discussed. The main advantages of this scheme are the availability of multi-ampere negative ion sources and the possibility to neutralize negative ions with very high efficiency. 15 references, 2 figures

  16. The origin of high activity but low CO(2) selectivity on binary PtSn in the direct ethanol fuel cell.

    Science.gov (United States)

    Jin, Jia-Mei; Sheng, Tian; Lin, Xiao; Kavanagh, Richard; Hamer, Philip; Hu, Peijun; Hardacre, Christopher; Martinez-Bonastre, Alex; Sharman, Jonathan; Thompsett, David; Lin, Wen-Feng

    2014-05-28

    The most active binary PtSn catalyst for direct ethanol fuel cell applications has been studied at 20 °C and 60 °C, using variable temperature electrochemical in situ FTIR. In comparison with Pt, binary PtSn inhibits ethanol dissociation to CO(a), but promotes partial oxidation to acetaldehyde and acetic acid. Increasing the temperature from 20 °C to 60 °C facilitates both ethanol dissociation to CO(a) and then further oxidation to CO2, leading to an increased selectivity towards CO2; however, acetaldehyde and acetic acid are still the main products. Potential-dependent phase diagrams for surface oxidants of OH(a) formation on Pt(111), Pt(211) and Sn modified Pt(111) and Pt(211) surfaces have been determined using density functional theory (DFT) calculations. It is shown that Sn promotes the formation of OH(a) with a lower onset potential on the Pt(111) surface, whereas an increase in the onset potential is found upon modification of the (211) surface. In addition, Sn inhibits the Pt(211) step edge with respect to ethanol C-C bond breaking compared with that found on the pure Pt, which reduces the formation of CO(a). Sn was also found to facilitate ethanol dehydrogenation and partial oxidation to acetaldehyde and acetic acid which, combined with the more facile OH(a) formation on the Pt(111) surface, gives us a clear understanding of the experimentally determined results. This combined electrochemical in situ FTIR and DFT study provides, for the first time, an insight into the long-term puzzling features of the high activity but low CO2 production found on binary PtSn ethanol fuel cell catalysts.

  17. RBAP, a Rhodamine B-Based Derivative: Synthesis, Crystal Structure Analysis, Molecular Simulation, and Its Application as a Selective Fluorescent Chemical Sensor for Sn2+

    Directory of Open Access Journals (Sweden)

    Xiaofeng Bao

    2014-06-01

    Full Text Available A new fluorescent chemosensor based on a Rhodamine B and a benzyl 3-aminopropanoate conjugate (RBAP was designed, synthesized, and structurally characterized. Its single crystal structure was obtained and analyzed by X-ray analysis. In a MeOH/H2O (2:3, v/v, pH 5.95 solution RBAP exhibits a high selectivity and excellent sensitivity for Sn2+ ions in the presence of many other metal cations. The binding analysis using the Job’s plot suggested the RBAP formed a 1:1 complex with Sn2+.

  18. RBAP, a Rhodamine B-Based Derivative: Synthesis, Crystal Structure Analysis, Molecular Simulation, and Its Application as a Selective Fluorescent Chemical Sensor for Sn2+

    OpenAIRE

    Xiaofeng Bao; Xiaowei Cao; Xuemei Nie; Yanyan Jin; Baojing Zhou

    2014-01-01

    A new fluorescent chemosensor based on a Rhodamine B and a benzyl 3-aminopropanoate conjugate (RBAP) was designed, synthesized, and structurally characterized. Its single crystal structure was obtained and analyzed by X-ray analysis. In a MeOH/H2O (2:3, v/v, pH 5.95) solution RBAP exhibits a high selectivity and excellent sensitivity for Sn2+ ions in the presence of many other metal cations. The binding analysis using the Job’s plot suggested the RBAP formed a 1:1 complex with Sn2+.

  19. Selective Attention and Inhibitory Deficits in ADHD: Does Subtype or Comorbidity Modulate Negative Priming Effects?

    Science.gov (United States)

    Pritchard, Verena E.; Neumann, Ewald; Rucklidge, Julia J.

    2008-01-01

    Selective attention has durable consequences for behavior and neural activation. Negative priming (NP) effects are assumed to reflect a critical inhibitory component of selective attention. The performance of adolescents with Attention Deficit/Hyperactivity Disorder (ADHD) was assessed across two conceptually based NP tasks within a selective…

  20. Selective Negative Allosteric Modulation Of Metabotropic Glutamate Receptors - A Structural Perspective of Ligands and Mutants

    DEFF Research Database (Denmark)

    Harpsøe, Kasper; Isberg, Vignir; Tehan, Benjamin G

    2015-01-01

    modulators. In this analysis, we make the first comprehensive structural comparison of all metabotropic glutamate receptors, placing selective negative allosteric modulators and critical mutants into the detailed context of the receptor binding sites. A better understanding of how the different m......Glu allosteric modulator binding modes relates to selective pharmacological actions will be very valuable for rational design of safer drugs....

  1. Green and Selective Fluorescent Sensor for Detection of Sn (IV) and Mo (VI) Based on Boron and Nitrogen-Co-Doped Carbon Dots.

    Science.gov (United States)

    Tabaraki, Reza; Abdi, Omran; Yousefipour, Sedigheh

    2017-03-01

    A green and simple microwave-assisted method was used to synthesis water-soluble boron and nitrogen-co-doped carbon dots (B-N-CDs). These B-N-CDs were successfully used for the fluorescent determination of Sn 4+ and Mo 6+ ions. This probe had a fast response time at pH = 4 with high sensitivity and selectivity. Linear correlation between F 0 /F and the concentration was seen in the range of 0.2-18 μM and 0.2-25 μM for Sn 4+ and Mo 6+ , respectively. Under optimum condition, the limit of detection (LOD) for Sn 4+ and Mo 6+ were 150 nM and 132 nM, respectively. The performance of the sensor was evaluated by different real samples such as tap, river and mineral water, canned fish sample and tomato samples.

  2. Selective androgen receptor modulators (SARMs) negatively regulate triple-negative breast cancer growth and epithelial:mesenchymal stem cell signaling.

    Science.gov (United States)

    Narayanan, Ramesh; Ahn, Sunjoo; Cheney, Misty D; Yepuru, Muralimohan; Miller, Duane D; Steiner, Mitchell S; Dalton, James T

    2014-01-01

    The androgen receptor (AR) is the most highly expressed steroid receptor in breast cancer with 75-95% of estrogen receptor (ER)-positive and 40-70% of ER-negative breast cancers expressing AR. Though historically breast cancers were treated with steroidal androgens, their use fell from favor because of their virilizing side effects and the emergence of tamoxifen. Nonsteroidal, tissue selective androgen receptor modulators (SARMs) may provide a novel targeted approach to exploit the therapeutic benefits of androgen therapy in breast cancer. Since MDA-MB-453 triple-negative breast cancer cells express mutated AR, PTEN, and p53, MDA-MB-231 triple-negative breast cancer cells stably expressing wildtype AR (MDA-MB-231-AR) were used to evaluate the in vitro and in vivo anti-proliferative effects of SARMs. Microarray analysis and epithelial:mesenchymal stem cell (MSC) co-culture signaling studies were performed to understand the mechanisms of action. Dihydrotestosterone and SARMs, but not bicalutamide, inhibited the proliferation of MDA-MB-231-AR. The SARMs reduced the MDA-MB-231-AR tumor growth and tumor weight by greater than 90%, compared to vehicle-treated tumors. SARM treatment inhibited the intratumoral expression of genes and pathways that promote breast cancer development through its actions on the AR. SARM treatment also inhibited the metastasis-promoting paracrine factors, IL6 and MMP13, and subsequent migration and invasion of epithelial:MSC co-cultures. 1. AR stimulation inhibits paracrine factors that are important for MSC interactions and breast cancer invasion and metastasis. 2. SARMs may provide promise as novel targeted therapies to treat AR-positive triple-negative breast cancer.

  3. Selective androgen receptor modulators (SARMs negatively regulate triple-negative breast cancer growth and epithelial:mesenchymal stem cell signaling.

    Directory of Open Access Journals (Sweden)

    Ramesh Narayanan

    Full Text Available The androgen receptor (AR is the most highly expressed steroid receptor in breast cancer with 75-95% of estrogen receptor (ER-positive and 40-70% of ER-negative breast cancers expressing AR. Though historically breast cancers were treated with steroidal androgens, their use fell from favor because of their virilizing side effects and the emergence of tamoxifen. Nonsteroidal, tissue selective androgen receptor modulators (SARMs may provide a novel targeted approach to exploit the therapeutic benefits of androgen therapy in breast cancer.Since MDA-MB-453 triple-negative breast cancer cells express mutated AR, PTEN, and p53, MDA-MB-231 triple-negative breast cancer cells stably expressing wildtype AR (MDA-MB-231-AR were used to evaluate the in vitro and in vivo anti-proliferative effects of SARMs. Microarray analysis and epithelial:mesenchymal stem cell (MSC co-culture signaling studies were performed to understand the mechanisms of action.Dihydrotestosterone and SARMs, but not bicalutamide, inhibited the proliferation of MDA-MB-231-AR. The SARMs reduced the MDA-MB-231-AR tumor growth and tumor weight by greater than 90%, compared to vehicle-treated tumors. SARM treatment inhibited the intratumoral expression of genes and pathways that promote breast cancer development through its actions on the AR. SARM treatment also inhibited the metastasis-promoting paracrine factors, IL6 and MMP13, and subsequent migration and invasion of epithelial:MSC co-cultures.1. AR stimulation inhibits paracrine factors that are important for MSC interactions and breast cancer invasion and metastasis. 2. SARMs may provide promise as novel targeted therapies to treat AR-positive triple-negative breast cancer.

  4. Fabrication of highly sensitive and selective H{sub 2} gas sensor based on SnO{sub 2} thin film sensitized with microsized Pd islands

    Energy Technology Data Exchange (ETDEWEB)

    Van Toan, Nguyen; Viet Chien, Nguyen; Van Duy, Nguyen [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No. 1, Dai Co Viet Road, Hanoi (Viet Nam); Si Hong, Hoang [School of Electrical Engineering (SEE), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam); Nguyen, Hugo [Division of Microsystems Technology, Department of Engineering Sciences, Uppsala University, 75237 Uppsala (Sweden); Duc Hoa, Nguyen [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No. 1, Dai Co Viet Road, Hanoi (Viet Nam); Van Hieu, Nguyen, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No. 1, Dai Co Viet Road, Hanoi (Viet Nam)

    2016-01-15

    Highlights: • H{sub 2} gas sensors based on SnO{sub 2} thin film sensitized with Pd islands were fabricated. • The sensors could monitor hazardous H{sub 2}n gas at low concentrations of 25–250 ppm. • H{sub 2} response of Pd/SnO{sub 2} is higher than that of Pt/SnO{sub 2} and Au/SnO{sub 2} sensors. • Enhancement of sensor performance was discussed based on spillover and diffusion mechanisms. - Abstract: Ultrasensitive and selective hydrogen gas sensor is vital component in safe use of hydrogen that requires a detection and alarm of leakage. Herein, we fabricated a H{sub 2} sensing devices by adopting a simple design of planar-type structure sensor in which the heater, electrode, and sensing layer were patterned on the front side of a silicon wafer. The SnO{sub 2} thin film-based sensors that were sensitized with microsized Pd islands were fabricated at a wafer-scale by using a sputtering system combined with micro-electronic techniques. The thicknesses of SnO{sub 2} thin film and microsized Pd islands were optimized to maximize the sensing performance of the devices. The optimized sensor could be used for monitoring hydrogen gas at low concentrations of 25–250 ppm, with a linear dependence to H{sub 2} concentration and a fast response and recovery time. The sensor also showed excellent selectivity for monitoring H{sub 2} among other gases, such as CO, NH{sub 3}, and LPG, and satisfactory characteristics for ensuring safety in handling hydrogen. The hydrogen sensing characteristics of the sensors sensitized with Pt and Au islands were also studied to clarify the sensing mechanisms.

  5. Rare earth chalcogels NaLnSnS{sub 4} (Ln = Y, Gd, Tb) for selective adsorption of volatile hydrocarbons and gases

    Energy Technology Data Exchange (ETDEWEB)

    Edhaim, Fatimah; Rothenberger, Alexander [Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2017-08-16

    The synthesis and characterization of the rare earth chalcogenide aerogels NaYSnS{sub 4}, NaGdSnS{sub 4}, and NaTbSnS{sub 4} is reported. Rare earth metal ions like Y{sup 3+}, Gd{sup 3+}, and Tb{sup 3+} react with the chalcogenide clusters [SnS{sub 4}]{sup 4-} in aqueous formamide solution forming extended polymeric networks by gelation. Aerogels obtained after supercritical drying have BET surface areas of 649 m{sup 2}.g{sup -1} (NaYSnS{sub 4}), 479 m{sup 2}.g{sup -1} (NaGdSnS{sub 4}), and 354 m{sup 2}.g{sup -1} (NaTbSnS{sub 4}). Electron microscopy and physisorption studies reveal that the new materials have pores in the macro (above 50 nm) and meso (2-50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO{sub 2} over CH{sub 4} or H{sub 2}. The notable adsorption capacity for toluene (NaYSnS{sub 4}: 1108 mg.g{sup -1}; NaGdSnS{sub 4}: 921 mg.g{sup -1}; and NaTbSnS4: 645 mg.g{sup -1}) and high selectivity for gases (CO{sub 2}/H{sub 2}: 172 and CO{sub 2}/CH{sub 4}: 50 for NaYSnS{sub 4}, CO{sub 2}/H{sub 2}: 155 and CO{sub 2}/CH{sub 4}: 37 for NaGdSnS{sub 4}, and CO{sub 2}/H{sub 2}: 75 and CO{sub 2}/CH{sub 4}: 28 for NaTbSnS{sub 4}) indicate potential future use of chalcogels in adsorption-based gas or hydrocarbon separation processes. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Cu-Sn Bimetallic Catalyst for Selective Aqueous Electroreduction of CO2 to CO

    KAUST Repository

    Sarfraz, Saad; Garcia Esparza, Angel T.; Jedidi, Abdesslem; Cavallo, Luigi; Takanabe, Kazuhiro

    2016-01-01

    electrocatalyst generates a surface that inhibits adsorbed H*, resulting in improved CO FE. This study presents a strategy to provide a low-cost non-noble metals that can be utilized as a highly selective electrocatalyst for the efficient aqueous reduction of CO2.

  7. Sensors based on mesoporous SnO{sub 2}-CuWO{sub 4} with high selective sensitivity to H{sub 2}S at low operating temperature

    Energy Technology Data Exchange (ETDEWEB)

    Stanoiu, Adelina; Simion, Cristian E. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Calderon-Moreno, Jose Maria; Osiceanu, Petre [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania); Florea, Mihaela [University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, B-dul Regina Elisabeta 4-12, Bucharest (Romania); National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Teodorescu, Valentin S. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Somacescu, Simona, E-mail: somacescu.simona@gmail.com [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania)

    2017-06-05

    Highlights: • Mesoporous SnO{sub 2}-CuWO{sub 4} obtained by an inexpensive synthesis route. • Powders characterization performed by a variety of complementary techniques. • SnO{sub 2}-CuWO{sub 4} layers with high selective sensitivity to H{sub 2}S. • Low operating temperature and relative humidity influences. - Abstract: Development of new sensitive materials by different synthesis routes in order to emphasize the sensing properties for hazardous H{sub 2}S detection is one of a nowadays challenge in the field of gas sensors. In this study we obtained mesoporous SnO{sub 2}-CuWO{sub 4} with selective sensitivity to H{sub 2}S by an inexpensive synthesis route with low environmental pollution level, using tripropylamine (TPA) as template and polyvinylpyrrolidone (PVP) as dispersant/stabilizer. In order to bring insights about the intrinsic properties, the powders were characterized by means of a variety of complementary techniques such as: X-Ray Diffraction, XRD; Transmission Electron Microscopy, TEM; High Resolution TEM, HRTEM; Raman Spectroscopy, RS; Porosity Analysis by N{sub 2} adsorption/desorption, BET; Scanning Electron Microscopy, SEM and X-ray Photoelectron Spectroscopy, XPS. The sensors were fabricated by powders deposition via screen-printing technique onto planar commercial Al{sub 2}O{sub 3} substrates. The sensor signals towards H{sub 2}S exposure at low operating temperature (100 °C) reaches values from 10{sup 5} (for SnWCu600) to 10{sup 6} (for SnWCu800) over the full range of concentrations (5–30 ppm). The recovery processes were induced by a short temperature trigger of 500 °C. The selective sensitivity was underlined with respect to the H{sub 2}S, relative to other potential pollutants and relative humidity (10–70% RH).

  8. Mode Selection Rules for a Two-Delay System with Positive and Negative Feedback Loops

    Science.gov (United States)

    Takahashi, Kin'ya; Kobayashi, Taizo

    2018-04-01

    The mode selection rules for a two-delay system, which has negative feedback with a short delay time t1 and positive feedback with a long delay time t2, are studied numerically and theoretically. We find two types of mode selection rules depending on the strength of the negative feedback. When the strength of the negative feedback |α1| (α1 0), 2m + 1-th harmonic oscillation is well sustained in a neighborhood of t1/t2 = even/odd, i.e., relevant condition. In a neighborhood of the irrelevant condition given by t1/t2 = odd/even or t1/t2 = odd/odd, higher harmonic oscillations are observed. However, if |α1| is slightly less than α2, a different mode selection rule works, where the condition t1/t2 = odd/even is relevant and the conditions t1/t2 = odd/odd and t1/t2 = even/odd are irrelevant. These mode selection rules are different from the mode selection rule of the normal two-delay system with two positive feedback loops, where t1/t2 = odd/odd is relevant and the others are irrelevant. The two types of mode selection rules are induced by individually different mechanisms controlling the Hopf bifurcation, i.e., the Hopf bifurcation controlled by the "boosted bifurcation process" and by the "anomalous bifurcation process", which occur for |α1| below and above the threshold value αth, respectively.

  9. Negative frequency-dependent selection between Pasteuria penetrans and its host Meloidogyne arenaria

    Science.gov (United States)

    In negative frequency-dependant selection (NFDS), parasite genotypes capable of infecting the numerically dominant host genotype are favored, while host genotypes resistant to the dominant parasite genotype are favored, creating a cyclical pattern of resistant genotypes in the host population and, a...

  10. A simple negative selection method to identify adenovirus recombinants using colony PCR

    Directory of Open Access Journals (Sweden)

    Yongliang Zhao

    2014-01-01

    Conclusions: The negative selection method to identify AdEasy adenovirus recombinants by colony PCR can identify the recombined colony within a short time-period, and maximally avoid damage to the recombinant plasmid by limiting recombination time, resulting in improved adenovirus packaging.

  11. Installation of spectrally selective imaging system in RF negative ion source

    International Nuclear Information System (INIS)

    Ikeda, K.; Kisaki, M.; Nagaoka, K.; Nakano, H.; Osakabe, M.; Tsumori, K.; Kaneko, O.; Takeiri, Y.; Wünderlich, D.; Fantz, U.; Heinemann, B.; Geng, S.

    2016-01-01

    A spectrally selective imaging system has been installed in the RF negative ion source in the International Thermonuclear Experimental Reactor-relevant negative ion beam test facility ELISE (Extraction from a Large Ion Source Experiment) to investigate distribution of hydrogen Balmer-α emission (H α ) close to the production surface of hydrogen negative ion. We selected a GigE vision camera coupled with an optical band-path filter, which can be controlled remotely using high speed network connection. A distribution of H α emission near the bias plate has been clearly observed. The same time trend on H α intensities measured by the imaging diagnostic and the optical emission spectroscopy is confirmed

  12. Improved negative selection protocol for Plasmodium berghei in the rodent malarial model

    Directory of Open Access Journals (Sweden)

    Orr Rachael Y

    2012-03-01

    Full Text Available Abstract An improved methodology is presented here for transgenic Plasmodium berghei lines that express the negative selectable marker yFCU (a bifunctional protein that combines yeast cytosine deaminase and uridyl phosphoribosyl transferase (UPRT and substitutes delivery of selection drug 5-fluorocytosine (5FC by intraperitoneal injection for administration via the drinking water of the mice. The improved methodology is shown to be as effective, less labour-intensive, reduces animal handling and animal numbers required for successful selection thereby contributing to two of the "three Rs" of animal experimentation, namely refinement and reduction.

  13. SN Refsdal

    DEFF Research Database (Denmark)

    Kelly, P. L.; Brammer, G.; Selsing, J.

    2016-01-01

    (SNe), and we find strong evidence for a broad H-alpha P-Cygni profile in the HST grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn, powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show...... in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, SN Refsdal has a blue B-V color and a high luminosity for the assumed range of potential magnifications. If SN Refsdal can be modeled as a scaled version of SN...

  14. How does male–male competition generate negative frequency-dependent selection and disruptive selection during speciation?

    Science.gov (United States)

    Border, Shana E

    2018-01-01

    Abstract Natural selection has been shown to drive population differentiation and speciation. The role of sexual selection in this process is controversial; however, most of the work has centered on mate choice while the role of male–male competition in speciation is relatively understudied. Here, we outline how male–male competition can be a source of diversifying selection on male competitive phenotypes, and how this can contribute to the evolution of reproductive isolation. We highlight how negative frequency-dependent selection (advantage of rare phenotype arising from stronger male–male competition between similar male phenotypes compared with dissimilar male phenotypes) and disruptive selection (advantage of extreme phenotypes) drives the evolution of diversity in competitive traits such as weapon size, nuptial coloration, or aggressiveness. We underscore that male–male competition interacts with other life-history functions and that variable male competitive phenotypes may represent alternative adaptive options. In addition to competition for mates, aggressive interference competition for ecological resources can exert selection on competitor signals. We call for a better integration of male–male competition with ecological interference competition since both can influence the process of speciation via comparable but distinct mechanisms. Altogether, we present a more comprehensive framework for studying the role of male–male competition in speciation, and emphasize the need for better integration of insights gained from other fields studying the evolutionary, behavioral, and physiological consequences of agonistic interactions. PMID:29492042

  15. Secure relay selection based on learning with negative externality in wireless networks

    Science.gov (United States)

    Zhao, Caidan; Xiao, Liang; Kang, Shan; Chen, Guiquan; Li, Yunzhou; Huang, Lianfen

    2013-12-01

    In this paper, we formulate relay selection into a Chinese restaurant game. A secure relay selection strategy is proposed for a wireless network, where multiple source nodes send messages to their destination nodes via several relay nodes, which have different processing and transmission capabilities as well as security properties. The relay selection utilizes a learning-based algorithm for the source nodes to reach their best responses in the Chinese restaurant game. In particular, the relay selection takes into account the negative externality of relay sharing among the source nodes, which learn the capabilities and security properties of relay nodes according to the current signals and the signal history. Simulation results show that this strategy improves the user utility and the overall security performance in wireless networks. In addition, the relay strategy is robust against the signal errors and deviations of some user from the desired actions.

  16. The negative priming paradigm: An update and implications for selective attention.

    Science.gov (United States)

    Frings, Christian; Schneider, Katja Kerstin; Fox, Elaine

    2015-12-01

    Negative Priming (NP) is an influential paradigm in cognitive psychology that was originally developed to measure attentional selection. Yet, up to the mid-1990s, a large number of experimental reports questioned whether the NP effect is based on attentional inhibition and/or episodic retrieval processes. In this review, we summarize findings since the mid-1990s and discuss new and old theoretical approaches to Negative Priming. We conclude that more than one process contributes to NP and that future research should analyze the conditions under which a particular process contributes to NP. Moreover, we argue that the paradigm--although it does not measure a single cognitive process alone--is still a useful tool for understanding selection in cognition. In fact, it might be a virtue of the paradigm that several cognitive processes work here together as selection in nonexperimental contexts is surely a multidimensional process. From this perspective, research on NP is relevant for all research fields analyzing selection. We therefore close our review by discussing the implications of the new evidence on NP for theories of selective attention.

  17. Re-editing and Censoring of Detectors in Negative Selection Algorithm

    Directory of Open Access Journals (Sweden)

    X.Z. Gao

    2009-12-01

    Full Text Available The Negative Selection Algorithm (NSA is a kind of novelty detection method inspired by the biological self/nonself discrimination principles. In this paper, we propose two new schemes for the detectors re-editing and censoring in the NSA. The detectors that fail to pass the negative selection phase are re-edited and updated to become qualified using the Differential Evolution (DE method. In the detectors censoring, the qualification of all the detectors is evaluated, and only those appropriate ones are retained. Prior knowledge of the anomalous data is utilized to discriminate the detectors so that their anomaly detection performances can be improved. The effectiveness of our detectors re-editing and censoring approaches is examined with both artificial signals and a practical bearings fault detection problem.

  18. Using Negative Reinforcement to Increase Self-Feeding in a Child with Food Selectivity

    Science.gov (United States)

    Vaz, Petula C. M.; Volkert, Valerie M.; Piazza, Cathleen C.

    2011-01-01

    We examined the effects of a negative reinforcement-based treatment on the self-feeding of 1 child with food selectivity by type and texture. Self-feeding increased when the child could choose to either self-feed 1 bite of a target food or be fed 1 bite of the target food and 5 bites of another food. Possible mechanisms that underlie the…

  19. Elimination of self-reactive T cells in the thymus: a timeline for negative selection.

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    Ivan Lilyanov Dzhagalov

    Full Text Available The elimination of autoreactive T cells occurs via thymocyte apoptosis and removal by thymic phagocytes, but the sequence of events in vivo, and the relationship between thymocyte death and phagocytic clearance, are unknown. Here we address these questions by following a synchronized cohort of thymocytes undergoing negative selection within a three-dimensional thymic tissue environment, from the initial encounter with a negative selecting ligand to thymocyte death and clearance. Encounter with cognate peptide-MHC complexes results in rapid calcium flux and migratory arrest in auto-reactive thymocytes over a broad range of peptide concentrations, followed by a lag period in which gene expression changes occurred, but there was little sign of thymocyte death. Caspase 3 activation and thymocyte loss were first detectable at 2 and 3 hours, respectively, and entry of individual thymocytes into the death program occurred asynchronously over the next 10 hours. Two-photon time-lapse imaging revealed that thymocyte death and phagocytosis occurred simultaneously, often with thymocytes engulfed prior to changes in chromatin and membrane permeability. Our data provide a timeline for negative selection and reveal close coupling between cell death and clearance in the thymus.

  20. Ni–Sn-Supported ZrO2 Catalysts Modified by Indium for Selective CO2 Hydrogenation to Methanol

    KAUST Repository

    Hengne, Amol Mahalingappa; Samal, Akshaya Kumar; Enakonda, Linga Reddy; Harb, Moussab; Gevers, Lieven; Anjum, Dalaver H.; Hedhili, Mohamed N.; Saih, Youssef; Huang, Kuo-Wei; Basset, Jean-Marie

    2018-01-01

    Ni and NiSn supported on zirconia (ZrO2) and on indium (In)-incorporated zirconia (InZrO2) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO2 to methanol in a fixed-bed isothermal flow reactor at 250 °C

  1. Impact of catalyst reduction mode on selective hydrogenation of cinnamaldehyde over Ru-Sn sol-gel catalysts

    Czech Academy of Sciences Publication Activity Database

    Hájek, J.; Kumar, N.; Salmi, T.; Murzin, DY.; Karhu, H.; Väyrynen, J.; Červený, L.; Paseka, Ivo

    2003-01-01

    Roč. 42, č. 2 (2003), s. 295-305 ISSN 0888-5885 R&D Projects: GA ČR GA104/00/1009 Institutional research plan: CEZ:AV0Z4032918 Keywords : Supported ruthenium catalysts * Ru-Sn-Al2O3 catalysts * benzene Subject RIV: CA - Inorganic Chemistry Impact factor: 1.317, year: 2003

  2. Depression and selection of positive and negative social feedback: motivated preference or cognitive balance?

    Science.gov (United States)

    Alloy, L B; Lipman, A J

    1992-05-01

    In this commentary we examine Swann, Wenzlaff, Krull, and Pelham's (1992) findings with respect to each of 5 central propositions in self-verification theory. We conclude that although the data are consistent with self-verification theory, none of the 5 components of the theory have been demonstrated convincingly as yet. Specifically, we argue that depressed subjects' selection of social feedback appears to be balanced or evenhanded rather than biased toward negative feedback and that there is little evidence to indicate that depressives actively seek negative appraisals. Furthermore, we suggest that the studies are silent with respect to the motivational postulates of self-verification theory and that a variety of competing cognitive and motivational models can explain Swann et al.'s findings as well as self-verification theory.

  3. Selective detection of acetone and hydrogen sulfide for the diagnosis of diabetes and halitosis using SnO(2) nanofibers functionalized with reduced graphene oxide nanosheets.

    Science.gov (United States)

    Choi, Seon-Jin; Jang, Bong-Hoon; Lee, Seo-Jin; Min, Byoung Koun; Rothschild, Avner; Kim, Il-Doo

    2014-02-26

    Sensitive detection of acetone and hydrogen sulfide levels in exhaled human breath, serving as breath markers for some diseases such as diabetes and halitosis, may offer useful information for early diagnosis of these diseases. Exhaled breath analyzers using semiconductor metal oxide (SMO) gas sensors have attracted much attention because they offer low cost fabrication, miniaturization, and integration into portable devices for noninvasive medical diagnosis. However, SMO gas sensors often display cross sensitivity to interfering species. Therefore, selective real-time detection of specific disease markers is a major challenge that must be overcome to ensure reliable breath analysis. In this work, we report on highly sensitive and selective acetone and hydrogen sulfide detection achieved by sensitizing electrospun SnO2 nanofibers with reduced graphene oxide (RGO) nanosheets. SnO2 nanofibers mixed with a small amount (0.01 wt %) of RGO nanosheets exhibited sensitive response to hydrogen sulfide (Rair/Rgas = 34 at 5 ppm) at 200 °C, whereas sensitive acetone detection (Rair/Rgas = 10 at 5 ppm) was achieved by increasing the RGO loading to 5 wt % and raising the operation temperature to 350 °C. The detection limit of these sensors is predicted to be as low as 1 ppm for hydrogen sulfide and 100 ppb for acetone, respectively. These concentrations are much lower than in the exhaled breath of healthy people. This demonstrates that optimization of the RGO loading and the operation temperature of RGO-SnO2 nanocomposite gas sensors enables highly sensitive and selective detection of breath markers for the diagnosis of diabetes and halitosis.

  4. Preparation and characterization of electrically conducting polypyrrole Sn(IV phosphate cation-exchanger and its application as Mn(II ion selective membrane electrode

    Directory of Open Access Journals (Sweden)

    A.A. Khan

    2011-10-01

    Full Text Available Polypyrrole Sn(IV phosphate, an organic–inorganic composite cation-exchanger was synthesized via sol-gel mixing of an organic polymer, polypyrrole, into the matrices of the inorganic precipitate of Sn(IV phosphate. The physico-chemical properties of the material were determined using Atomic Absorption Spectrometry (AAS, CHN elemental analysis (inductively coupled plasma mass spectrometry, ICP-MS, UV–VIS spectrophotometry, FTIR (Fourier Transform Infra-Red, SEM (Scanning Electron Microscopy, TGA–DTA (Thermogravimetric Analysis–Differential Thermal Analysis, and XRD (X-ray diffraction. Ion-exchange behavior was observed to characterize the material. On the basis of distribution studies, the material was found to be highly selective for toxic heavy metal ion Mn2+. Due to its selective nature, the material was used as an electroactive component for the construction of an ion-selective membrane electrode. The proposed electrode shows fairly good discrimination of mercury ion over several other inorganic ions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations for Mn(II in water.

  5. A Negative Selection Immune System Inspired Methodology for Fault Diagnosis of Wind Turbines.

    Science.gov (United States)

    Alizadeh, Esmaeil; Meskin, Nader; Khorasani, Khashayar

    2017-11-01

    High operational and maintenance costs represent as major economic constraints in the wind turbine (WT) industry. These concerns have made investigation into fault diagnosis of WT systems an extremely important and active area of research. In this paper, an immune system (IS) inspired methodology for performing fault detection and isolation (FDI) of a WT system is proposed and developed. The proposed scheme is based on a self nonself discrimination paradigm of a biological IS. Specifically, the negative selection mechanism [negative selection algorithm (NSA)] of the human body is utilized. In this paper, a hierarchical bank of NSAs are designed to detect and isolate both individual as well as simultaneously occurring faults common to the WTs. A smoothing moving window filter is then utilized to further improve the reliability and performance of the FDI scheme. Moreover, the performance of our proposed scheme is compared with another state-of-the-art data-driven technique, namely the support vector machines (SVMs) to demonstrate and illustrate the superiority and advantages of our proposed NSA-based FDI scheme. Finally, a nonparametric statistical comparison test is implemented to evaluate our proposed methodology with that of the SVM under various fault severities.

  6. Human Commercial Models' Eye Colour Shows Negative Frequency-Dependent Selection.

    Directory of Open Access Journals (Sweden)

    Isabela Rodrigues Nogueira Forti

    Full Text Available In this study we investigated the eye colour of human commercial models registered in the UK (400 female and 400 male and Brazil (400 female and 400 male to test the hypothesis that model eye colour frequency was the result of negative frequency-dependent selection. The eye colours of the models were classified as: blue, brown or intermediate. Chi-square analyses of data for countries separated by sex showed that in the United Kingdom brown eyes and intermediate colours were significantly more frequent than expected in comparison to the general United Kingdom population (P<0.001. In Brazil, the most frequent eye colour brown was significantly less frequent than expected in comparison to the general Brazilian population. These results support the hypothesis that model eye colour is the result of negative frequency-dependent selection. This could be the result of people using eye colour as a marker of genetic diversity and finding rarer eye colours more attractive because of the potential advantage more genetically diverse offspring that could result from such a choice. Eye colour may be important because in comparison to many other physical traits (e.g., hair colour it is hard to modify, hide or disguise, and it is highly polymorphic.

  7. Topology of evolving, mutagenized viral populations: quasispecies expansion, compression, and operation of negative selection.

    Science.gov (United States)

    Ojosnegros, Samuel; Agudo, Rubén; Sierra, Macarena; Briones, Carlos; Sierra, Saleta; González-López, Claudia; Domingo, Esteban; Cristina, Juan

    2008-07-17

    The molecular events and evolutionary forces underlying lethal mutagenesis of virus (or virus extinction through an excess of mutations) are not well understood. Here we apply for the first time phylogenetic methods and Partition Analysis of Quasispecies (PAQ) to monitor genetic distances and intra-population structures of mutant spectra of foot-and-mouth disease virus (FMDV) quasispecies subjected to mutagenesis by base and nucleoside analogues. Phylogenetic and PAQ analyses have revealed a highly dynamic variation of intrapopulation diversity of FMDV quasispecies. The population diversity first suffers striking expansions in the presence of mutagens and then compressions either when the presence of the mutagenic analogue was discontinued or when a mutation that decreased sensitivity to a mutagen was selected. The pattern of mutations found in the populations was in agreement with the behavior of the corresponding nucleotide analogues with FMDV in vitro. Mutations accumulated at preferred genomic sites, and dn/ds ratios indicate the operation of negative (or purifying) selection in populations subjected to mutagenesis. No evidence of unusually elevated genetic distances has been obtained for FMDV populations approaching extinction. Phylogenetic and PAQ analysis provide adequate procedures to describe the evolution of viral sequences subjected to lethal mutagenesis. These methods define the changes of intra-population structure more precisely than mutation frequencies and Shannon entropies. PAQ is very sensitive to variations of intrapopulation genetic distances. Strong negative (or purifying) selection operates in FMDV populations subjected to enhanced mutagenesis. The quantifications provide evidence that extinction does not imply unusual increases of intrapopulation complexity, in support of the lethal defection model of virus extinction.

  8. Topology of evolving, mutagenized viral populations: quasispecies expansion, compression, and operation of negative selection

    Directory of Open Access Journals (Sweden)

    Sierra Saleta

    2008-07-01

    Full Text Available Abstract Background The molecular events and evolutionary forces underlying lethal mutagenesis of virus (or virus extinction through an excess of mutations are not well understood. Here we apply for the first time phylogenetic methods and Partition Analysis of Quasispecies (PAQ to monitor genetic distances and intra-population structures of mutant spectra of foot-and-mouth disease virus (FMDV quasispecies subjected to mutagenesis by base and nucleoside analogues. Results Phylogenetic and PAQ analyses have revealed a highly dynamic variation of intrapopulation diversity of FMDV quasispecies. The population diversity first suffers striking expansions in the presence of mutagens and then compressions either when the presence of the mutagenic analogue was discontinued or when a mutation that decreased sensitivity to a mutagen was selected. The pattern of mutations found in the populations was in agreement with the behavior of the corresponding nucleotide analogues with FMDV in vitro. Mutations accumulated at preferred genomic sites, and dn/ds ratios indicate the operation of negative (or purifying selection in populations subjected to mutagenesis. No evidence of unusually elevated genetic distances has been obtained for FMDV populations approaching extinction. Conclusion Phylogenetic and PAQ analysis provide adequate procedures to describe the evolution of viral sequences subjected to lethal mutagenesis. These methods define the changes of intra-population structure more precisely than mutation frequencies and Shannon entropies. PAQ is very sensitive to variations of intrapopulation genetic distances. Strong negative (or purifying selection operates in FMDV populations subjected to enhanced mutagenesis. The quantifications provide evidence that extinction does not imply unusual increases of intrapopulation complexity, in support of the lethal defection model of virus extinction.

  9. Models of Aire-dependent gene regulation for thymic negative selection

    Directory of Open Access Journals (Sweden)

    Dina eDanso-Abeam

    2011-05-01

    Full Text Available Mutations in the Autoimmune Regulator (AIRE gene lead to Autoimmune Polyendocrinopathy Syndrome type 1 (APS1, characterized by the development of multi-organ autoimmune damage. The mechanism by which defects in AIRE result in autoimmunity has been the subject of intense scrutiny. At the cellular level, the working model explains most of the clinical and immunological characteristics of APS1, with AIRE driving the expression of tissue restricted antigens (TRAs in the epithelial cells of the thymic medulla. This TRA expression results in effective negative selection of TRA-reactive thymocytes, preventing autoimmune disease. At the molecular level, the mechanism by which AIRE initiates TRA expression in the thymic medulla remains unclear. Multiple different models for the molecular mechanism have been proposed, ranging from classical transcriptional activity, to random induction of gene expression, to epigenetic tag recognition effect, to altered cell biology. In this review, we evaluate each of these models and discuss their relative strengths and weaknesses.

  10. Inhibition in the Dynamics of Selective Attention: An Integrative Model for Negative Priming

    Directory of Open Access Journals (Sweden)

    Hecke eSchrobsdorff

    2012-11-01

    Full Text Available We introduce a computational model of the negative priming (NP effect that includes perception, memory, attention, decision making, and action. The model is designed to provide a coherent picture across competing theories of NP and to relate psychological experiments to physiological measurements. The model is formulated in terms of an abstract dynamics of activations of features, their binding into object entities or their semantic categorization as well as related memories and implied reactions. The dynamical variables interact in a connectionist network which is shown to be adaptable to a variety of experimental paradigms. We find that selective attention can be modeled by means of inhibitory processes and by a threshold dynamics. Considering the implementation it becomes obvious that the specificity of the experimental paradigm must be taken into account when predicting the nature of the NP effect.

  11. A General Model of Negative Frequency Dependent Selection Explains Global Patterns of Human ABO Polymorphism.

    Directory of Open Access Journals (Sweden)

    Fernando A Villanea

    Full Text Available The ABO locus in humans is characterized by elevated heterozygosity and very similar allele frequencies among populations scattered across the globe. Using knowledge of ABO protein function, we generated a simple model of asymmetric negative frequency dependent selection and genetic drift to explain the maintenance of ABO polymorphism and its loss in human populations. In our models, regardless of the strength of selection, models with large effective population sizes result in ABO allele frequencies that closely match those observed in most continental populations. Populations must be moderately small to fall out of equilibrium and lose either the A or B allele (N(e ≤ 50 and much smaller (N(e ≤ 25 for the complete loss of diversity, which nearly always involved the fixation of the O allele. A pattern of low heterozygosity at the ABO locus where loss of polymorphism occurs in our model is consistent with small populations, such as Native American populations. This study provides a general evolutionary model to explain the observed global patterns of polymorphism at the ABO locus and the pattern of allele loss in small populations. Moreover, these results inform the range of population sizes associated with the recent human colonization of the Americas.

  12. A modified Janus cassette (Sweet Janus to improve allelic replacement efficiency by high-stringency negative selection in Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Yuan Li

    Full Text Available The Janus cassette permits marker-free allelic replacement or knockout in streptomycin-resistant Streptococcus pneumoniae (pneumococcus through sequential positive and negative selection. Spontaneous revertants of Janus can lead to high level of false-positives during negative selection, which necessitate a time-consuming post-selection screening process. We hypothesized that an additional counter-selectable marker in Janus would decrease the revertant frequency and reduce false-positives, since simultaneous reversion of both counter-selectable makers is much less likely. Here we report a modified cassette, Sweet Janus (SJ, in which the sacB gene from Bacillus subtilis conferring sucrose sensitivity is added to Janus. By using streptomycin and sucrose simultaneously as selective agents, the frequency of SJ double revertants was about 105-fold lower than the frequency of Janus revertants. Accordingly, the frequency of false-positives in the SJ-mediated negative selection was about 100-fold lower than what was seen for Janus. Thus, SJ enhances negative selection stringency and can accelerate allelic replacement in pneumococcus, especially when transformation frequency is low due to strain background or suboptimal transformation conditions. Results also suggested the sacB gene alone can function as a counter-selectable marker in the Gram-positive pneumococcus, which will have the advantage of not requiring a streptomycin-resistant strain for allelic replacement.

  13. Antibacterial properties of biosurfactants against selected Gram-positive and -negative bacteria.

    Science.gov (United States)

    Díaz De Rienzo, Mayri A; Stevenson, Paul; Marchant, Roger; Banat, Ibrahim M

    2016-01-01

    The antibacterial properties and ability to disrupt biofilms of biosurfactants (rhamnolipids, sophorolipids) and sodium dodecyl sulphate (SDS) in the presence and absence of selected organic acids were investigated. Pseudomonas aeruginosa PAO1 was inhibited by sophorolipids and SDS at concentrations >5% v/v, and the growth of Escherichia coli NCTC 10418 was also inhibited by sophorolipids and SDS at concentrations >5% and 0.1% v/v, respectively. Bacillus subtilis NCTC 10400 was inhibited by rhamnolipids, sophorolipids and SDS at concentrations >0.5% v/v of all three; the same effect was observed with Staphylococcus aureus ATCC 9144. The ability to attach to surfaces and biofilm formation of P. aeruginosa PAO1, E. coli NCTC 10418 and B. subtilis NCTC 10400 was inhibited by sophorolipids (1% v/v) in the presence of caprylic acid (0.8% v/v). In the case of S. aureus ATCC 9144, the best results were obtained using caprylic acid on its own. It was concluded that sophorolipids are promising compounds for the inhibition/disruption of biofilms formed by Gram-positive and Gram-negative microorganisms and this activity can be enhanced by the presence of booster compounds such as caprylic acid. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. A Quick Negative Selection Algorithm for One-Class Classification in Big Data Era

    Directory of Open Access Journals (Sweden)

    Fangdong Zhu

    2017-01-01

    Full Text Available Negative selection algorithm (NSA is an important kind of the one-class classification model, but it is limited in the big data era due to its low efficiency. In this paper, we propose a new NSA based on Voronoi diagrams: VorNSA. The scheme of the detector generation process is changed from the traditional “Random-Discard” model to the “Computing-Designated” model by VorNSA. Furthermore, we present an immune detection process of VorNSA under Map/Reduce framework (VorNSA/MR to further reduce the time consumption on massive data in the testing stage. Theoretical analyses show that the time complexity of VorNSA decreases from the exponential level to the logarithmic level. Experiments are performed to compare the proposed technique with other NSAs and one-class classifiers. The results show that the time cost of the VorNSA is averagely decreased by 87.5% compared with traditional NSAs in UCI skin dataset.

  15. Group IVA Element (Si, Ge, Sn)-Based Alloying/Dealloying Anodes as Negative Electrodes for Full-Cell Lithium-Ion Batteries.

    Science.gov (United States)

    Liu, Dequan; Liu, Zheng Jiao; Li, Xiuwan; Xie, Wenhe; Wang, Qi; Liu, Qiming; Fu, Yujun; He, Deyan

    2017-12-01

    To satisfy the increasing energy demands of portable electronics, electric vehicles, and miniaturized energy storage devices, improvements to lithium-ion batteries (LIBs) are required to provide higher energy/power densities and longer cycle lives. Group IVA element (Si, Ge, Sn)-based alloying/dealloying anodes are promising candidates for use as electrodes in next-generation LIBs owing to their extremely high gravimetric and volumetric capacities, low working voltages, and natural abundances. However, due to the violent volume changes that occur during lithium-ion insertion/extraction and the formation of an unstable solid electrolyte interface, the use of Group IVA element-based anodes in commercial LIBs is still a great challenge. Evaluating the electrochemical performance of an anode in a full-cell configuration is a key step in investigating the possible application of the active material in LIBs. In this regard, the recent progress and important approaches to overcoming and alleviating the drawbacks of Group IVA element-based anode materials are reviewed, such as the severe volume variations during cycling and the relatively brittle electrode/electrolyte interface in full-cell LIBs. Finally, perspectives and future challenges in achieving the practical application of Group IVA element-based anodes in high-energy and high-power-density LIB systems are proposed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Refinement of Triple-Negative Breast Cancer Molecular Subtypes: Implications for Neoadjuvant Chemotherapy Selection.

    Directory of Open Access Journals (Sweden)

    Brian D Lehmann

    Full Text Available Triple-negative breast cancer (TNBC is a heterogeneous disease that can be classified into distinct molecular subtypes by gene expression profiling. Considered a difficult-to-treat cancer, a fraction of TNBC patients benefit significantly from neoadjuvant chemotherapy and have far better overall survival. Outside of BRCA1/2 mutation status, biomarkers do not exist to identify patients most likely to respond to current chemotherapy; and, to date, no FDA-approved targeted therapies are available for TNBC patients. Previously, we developed an approach to identify six molecular subtypes TNBC (TNBCtype, with each subtype displaying unique ontologies and differential response to standard-of-care chemotherapy. Given the complexity of the varying histological landscape of tumor specimens, we used histopathological quantification and laser-capture microdissection to determine that transcripts in the previously described immunomodulatory (IM and mesenchymal stem-like (MSL subtypes were contributed from infiltrating lymphocytes and tumor-associated stromal cells, respectively. Therefore, we refined TNBC molecular subtypes from six (TNBCtype into four (TNBCtype-4 tumor-specific subtypes (BL1, BL2, M and LAR and demonstrate differences in diagnosis age, grade, local and distant disease progression and histopathology. Using five publicly available, neoadjuvant chemotherapy breast cancer gene expression datasets, we retrospectively evaluated chemotherapy response of over 300 TNBC patients from pretreatment biopsies subtyped using either the intrinsic (PAM50 or TNBCtype approaches. Combined analysis of TNBC patients demonstrated that TNBC subtypes significantly differ in response to similar neoadjuvant chemotherapy with 41% of BL1 patients achieving a pathological complete response compared to 18% for BL2 and 29% for LAR with 95% confidence intervals (CIs; [33, 51], [9, 28], [17, 41], respectively. Collectively, we provide pre-clinical data that could inform

  17. Effects of organic solvent, water activity, and salt hydrate pair on the sn-1,3 selectivity and activity of whole-cell lipase from Aspergillus niger GZUF36.

    Science.gov (United States)

    Li, Cuiqin; Zhang, Fuhao; Gao, Zexin; He, Laping; Zeng, Xuefeng; Zhu, Qiujin; Yu, Lijuan

    2018-01-01

    We previously screened a whole-cell lipase EC 3.1.1.3 from the novel strain Aspergillus niger GZUF36, which exhibited 1,3-selectivity in the synthesis of 1,3-diacylglycerol via glycerolysis. However, the mechanism of lipase selectively in catalyzing the sn-1,3 position remains ambiguous. This work was performed to investigate the 1,3-selective mechanism of lipase using glycerolysis to synthesize 1,3-diacylglycerol (1,3-DG) as a model reaction by changing solvent(s) and water activity (a w ), and addition of salt hydrate pair. The measured diacylglycerol yield was also used to examine lipase activity. Results indicated that not only organic solvent and a w have strong effect on the sn-1,3 selectivity, but also ions of salt hydrate pair also affected selectivity. Lipase conformation was altered by hydrophobic interactions of the solvent, a w , or ions of salt hydrate, resulting in distinct sn-1,3 selectivity of the lipase. The salt hydrate pair changed the lipase conformation and selectivity not only by a w but also by static interactions, which was rarely reported. These parameters also affected lipase activity. The lipase displayed the highest selectivity (about 88%) and activity in solvents of t-butanol and n-hexane (1:29, v/v) at a w 0.43. The results demonstrated that the sn-1,3 selectivity and activity of the lipase from A. niger GZUF36 may be improved by control of some crucial factors. This work laid a foundation for the application of lipase in the synthesis of 1,3-DG and other structural and functional lipids.

  18. Comparison of confirmed inactive and randomly selected compounds as negative training examples in support vector machine-based virtual screening.

    Science.gov (United States)

    Heikamp, Kathrin; Bajorath, Jürgen

    2013-07-22

    The choice of negative training data for machine learning is a little explored issue in chemoinformatics. In this study, the influence of alternative sets of negative training data and different background databases on support vector machine (SVM) modeling and virtual screening has been investigated. Target-directed SVM models have been derived on the basis of differently composed training sets containing confirmed inactive molecules or randomly selected database compounds as negative training instances. These models were then applied to search background databases consisting of biological screening data or randomly assembled compounds for available hits. Negative training data were found to systematically influence compound recall in virtual screening. In addition, different background databases had a strong influence on the search results. Our findings also indicated that typical benchmark settings lead to an overestimation of SVM-based virtual screening performance compared to search conditions that are more relevant for practical applications.

  19. Influence of negative affect on selective attention to smoking-related cues and urge to smoke in cigarette smokers.

    Science.gov (United States)

    Bradley, Brendan P; Garner, Matthew; Hudson, Laura; Mogg, Karin

    2007-07-01

    According to recent models of addiction, negative affect plays an important role in maintaining drug dependence. The study investigated the effect of negative mood on attentional biases for smoking-related cues and smoking urge in cigarette smokers. Eye movements to smoking-related and control pictures, and manual response times to probes, were recorded during a visual probe task. Smoking urges and mood were assessed by self-report measures. Negative affect was manipulated experimentally as a within-participants independent variable; that is, each participant received negative and neutral mood induction procedures, in counterbalanced order in separate sessions, before the attentional task. There were two groups of participants: smokers and nonsmokers. Smokers showed (i) a greater tendency to shift gaze initially towards smoking-related cues, and (ii) greater urge to smoke when they were in negative mood compared with neutral mood. Manual response time data suggested that smokers showed a greater tendency than nonsmokers to maintain attention on smoking-related cues, irrespective of mood. The results offer partial support for the view that negative mood increases selective attention to drug cues, and urge to smoke, in smokers. The findings are discussed in relation to an affective processing model of negative reinforcement in drug dependence.

  20. Effect of metal ions doping (M = Ti4+, Sn4+) on the catalytic performance of MnOx/CeO2 catalyst for low temperature selective catalytic reduction of NO with NH3

    Science.gov (United States)

    Xiong, Yan; Tang, Changjin; Dong, Lin

    2015-04-01

    Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China The abatement of nitrogen oxides (NOx) emission from exhaust gases of diesel and stationary sources is a significant challenge for economic and social development. Ceria-based solid solutions were synthesized and used as supports to prepare MnOx/Ce0.8Ti0.2O2 and MnOx/Ce0.8Sn0.2O2 catalysts (Mn/CeTi and Mn/CeSn) for low temperature selective catalytic reduction of NO by NH3 (NH3-SCR). The effects of Ti or Sn doping on the catalytic performance of MnOx/CeO2 catalyst were investigated. Experimental results show that doping of Ti or Sn increases the NO removal efficiency of MnOx/CeO2. The NO conversion of Mn/CeTi catalyst is more than 90 % at temperature window of 175 ~ 300 °C under a gas hour space velocity of 60,000 mL.g-1.h-1. Modified catalysts are also found to exhibit greatly improved resistance to sulfur-poisoning. NH3-TPD results suggest that NH3 desorption on the catalysts is observed over a wide temperature range, due to the variability of adsorbed NH3 species with different thermal stabilities. Doping of Ti and Sn into Mn/CeO2 greatly increased the NH3 adsorption ability of the composites which could promote the SCR reaction. Characterization results also indicate that doping of Ti or Sn brings about catalysts with higher BET surface area, enhanced oxygen storage capacity and increased surface acidity.

  1. Negative in vitro selection identifies the rRNA recognition motif for ErmE methyltransferase

    DEFF Research Database (Denmark)

    Nielsen, Allan K.; Douthwaite, Stephen; Vester, Birte

    1999-01-01

    -mer RNA. The RNAs were passed through a series of rounds of methylation with ErmE. After each round, RNAs were selected that had partially or completely lost their ability to be methylated. After several rounds of methylation/selection, 187 subclones were analyzed. Forty-three of the subclones...

  2. Who Benefits Most from College? Evidence for Negative Selection in Heterogeneous Economic Returns to Higher Education

    Science.gov (United States)

    Brand, Jennie E.; Yu Xie,

    2010-01-01

    In this article, we consider how the economic return to a college education varies across members of the U.S. population. Based on principles of comparative advantage, scholars commonly presume that positive selection is at work, that is, individuals who are most likely to select into college also benefit most from college. Net of observed…

  3. The role of the negative selection activities in securing the competence of an organization belonging to SEN units

    International Nuclear Information System (INIS)

    Boruga, Carmen

    2008-01-01

    The transformation and the accommodation of National Power System (SEN) units to a new management system, own to a decentralized economy and having financial support from both native capital and foreign capital, in uncertain proportion at the moment and being in a continuous adjustment determined by the reasons and the motivations first of all political, generated conceptual changes in the so-called modern management theory. The accommodation of this theory to the concrete situation from SEN units imposed the concept of negative selection. It is a concept which represents author's desire to be created as an original contribution to the contemporary management theory. Unlike the selection at the hiring (or positive selection), the negative selection is achieved on personal already employed, in the conditions of activities of a decreased number of personnel and also of a redistribution of personnel on the other side. The negative selection, much more than the positive selection activity in this period in the SEN units (recording a drastic decrease from 90.000 employees counted by the energetic system at the end of 9th decade of the past century, to a little over 30.000 who at the moment work in the societies became independent), determines the specialist in human resources to ensure a judicious training and high competence. It concerns the knowledge of the standard systems and is also related to the method of knowledge and valuation of behavior of the organizational employees. This subject was developed on basis of the documentation and the analyses of documents but also on the basis of a set of studies and researches that were made during 1996-2006 in the SEN units. The work methods and models of negative selection used in the SEN units were analysed. This work concerns four companies which constitute currently the SEN nucleus at present at which the nuclear units with a particular status were added. One finds out that these methods and models of negative selection

  4. Personnel selection and emotional stability certification: establishing a false negative error rate when clinical interviews

    International Nuclear Information System (INIS)

    Berghausen, P.E. Jr.

    1987-01-01

    The security plans of nuclear plants generally require that all personnel who are to have unescorted access to protected areas or vital islands be screened for emotional instability. Screening typically consists of first administering the MMPI and then conducting a clinical interview. Interviews-by-exception protocols provide for only those employees to be interviewed who have some indications of psychopathology in their MMPI results. A problem arises when the indications are not readily apparent: False negatives are likely to occur, resulting in employees being erroneously granted unescorted access. The present paper describes the development of a predictive equation which permits accurate identification, via analysis of MMPI results, of those employees who are most in need of being interviewed. The predictive equation also permits knowing probably maximum false negative error rates when a given percentage of employees is interviewed

  5. Antibiotic-mediated selection of quorum-sensing-negative Staphylococcus aureus

    DEFF Research Database (Denmark)

    Paulander, Wilhelm Erik Axel; Varming, Anders Nissen; Bæk, Kristoffer Torbjørn

    2012-01-01

    of glycopeptide resistance greater than those of other strains. We show here that agr-negative strains have a fitness advantage over agr-positive strains in the presence of sublethal concentrations of some antibiotics and that the fitness defect of agr-positive cells is caused by antibiotic-mediated expression...... expression. We demonstrate that the presence of the agr locus imposes a fitness cost on S. aureus that is mediated by the expression of RNAIII. Further, we show that exposure to sublethal levels of the antibiotics ciprofloxacin, mupirocin, and rifampin, each targeting separate cellular functions, markedly...... increases the agr-mediated fitness cost by inducing the expression of RNAIII. Thus, the extensive use of antibiotics in hospitals may explain why agr-negative variants are frequently isolated from hospital-acquired S. aureus infections but rarely found among community-acquired S. aureus strains. Importantly...

  6. Construction and applications of exon-trapping gene-targeting vectors with a novel strategy for negative selection.

    Science.gov (United States)

    Saito, Shinta; Ura, Kiyoe; Kodama, Miho; Adachi, Noritaka

    2015-06-30

    Targeted gene modification by homologous recombination provides a powerful tool for studying gene function in cells and animals. In higher eukaryotes, non-homologous integration of targeting vectors occurs several orders of magnitude more frequently than does targeted integration, making the gene-targeting technology highly inefficient. For this reason, negative-selection strategies have been employed to reduce the number of drug-resistant clones associated with non-homologous vector integration, particularly when artificial nucleases to introduce a DNA break at the target site are unavailable or undesirable. As such, an exon-trap strategy using a promoterless drug-resistance marker gene provides an effective way to counterselect non-homologous integrants. However, constructing exon-trapping targeting vectors has been a time-consuming and complicated process. By virtue of highly efficient att-mediated recombination, we successfully developed a simple and rapid method to construct plasmid-based vectors that allow for exon-trapping gene targeting. These exon-trap vectors were useful in obtaining correctly targeted clones in mouse embryonic stem cells and human HT1080 cells. Most importantly, with the use of a conditionally cytotoxic gene, we further developed a novel strategy for negative selection, thereby enhancing the efficiency of counterselection for non-homologous integration of exon-trap vectors. Our methods will greatly facilitate exon-trapping gene-targeting technologies in mammalian cells, particularly when combined with the novel negative selection strategy.

  7. A bacterial haloalkane dehalogenase gene as a negative selectable marker in Arabidopsis

    DEFF Research Database (Denmark)

    Næsted, Henrik; Fennema, M.; Hao, L.

    1999-01-01

    , including Arabidopsis, tobacco, oil seed rape and rice, do not express detectable haloalkane dehalogenase activities, and that wild-type Arabidopsis grows in the presence of DCE. In contrast, DCE applied as a volatile can be used to select on plates or in soil transgenic Arabidopsis which express dhl...

  8. Negative ion formation in dissociative electron attachment to selected halogen derivatives of propane

    Science.gov (United States)

    Barszczewska, W.; Kocísek, J.; Skalný, J.; Matejcík, V.; Matejcík, S.

    2008-11-01

    Dissociative electron attachment (DEA) to halogenated derivatives of propane: 1-bromo-3-chloropropane, 2-bromo-1-chloropropane, 3-bromo-1,1,1-trichloropropane and 1,3-dibromo-1,1-difluoropropane was studied in the gas phase at ambient temperature using a high resolution crossed electron/molecule beams technique. The negative ions formed via DEA reaction were identified using mass spectrometric technique and the anion yields were measured in the electron energy range from 0 to 10 eV. The absolute partial cross sections for DEA to the molecules were estimated using the relative flow technique.

  9. Selection of Novel Peptides Homing the 4T1 CELL Line: Exploring Alternative Targets for Triple Negative Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Vera L Silva

    Full Text Available The use of bacteriophages to select novel ligands has been widely explored for cancer therapy. Their application is most warranted in cancer subtypes lacking knowledge on how to target the cancer cells in question, such as the triple negative breast cancer, eventually leading to the development of alternative nanomedicines for cancer therapeutics. Therefore, the following study aimed to select and characterize novel peptides for a triple negative breast cancer murine mammary carcinoma cell line- 4T1. Using phage display, 7 and 12 amino acid random peptide libraries were screened against the 4T1 cell line. A total of four rounds, plus a counter-selection round using the 3T3 murine fibroblast cell line, was performed. The enriched selective peptides were characterized and their binding capacity towards 4T1 tissue samples was confirmed by immunofluorescence and flow cytometry analysis. The selected peptides (4T1pep1 -CPTASNTSC and 4T1pep2-EVQSSKFPAHVS were enriched over few rounds of selection and exhibited specific binding to the 4T1 cell line. Interestingly, affinity to the human MDA-MB-231 cell line was also observed for both peptides, promoting the translational application of these novel ligands between species. Additionally, bioinformatics analysis suggested that both peptides target human Mucin-16. This protein has been implicated in different types of cancer, as it is involved in many important cellular functions. This study strongly supports the need of finding alternative targeting systems for TNBC and the peptides herein selected exhibit promising future application as novel homing peptides for breast cancer therapy.

  10. Dominant negative selection of vaccinia virus using a thymidine kinase/thymidylate kinase fusion gene and the prodrug azidothymidine

    International Nuclear Information System (INIS)

    Holzer, Georg W.; Mayrhofer, Josef; Gritschenberger, Werner; Falkner, Falko G.

    2005-01-01

    The Escherichia coli thymidine kinase/thymidylate kinase (tk/tmk) fusion gene encodes an enzyme that efficiently converts the prodrug 3'-azido-2',3'-dideoxythymidine (AZT) into its toxic triphosphate derivative, a substance which stops DNA chain elongation. Integration of this marker gene into vaccinia virus that normally is not inhibited by AZT allowed the establishment of a powerful selection procedure for recombinant viruses. In contrast to the conventional vaccinia thymidine kinase (tk) selection that is performed in tk-negative cell lines, AZT selection can be performed in normal (tk-positive) cell lines. The technique is especially useful for the generation of replication-deficient vaccinia viruses and may also be used for gene knock-out studies of essential vaccinia genes

  11. The relationships of coping, negative thinking, life satisfaction, social support, and selected demographics with anxiety of young adult college students.

    Science.gov (United States)

    Mahmoud, Jihan S R; Staten, Ruth Topsy; Lennie, Terry A; Hall, Lynne A

    2015-05-01

    Understanding young adults' anxiety requires applying a multidimensional approach to assess the psychosocial, behavioral, and cognitive aspects of this phenomenon. A hypothesized model of the relationships among coping style, thinking style, life satisfaction, social support, and selected demographics and anxiety among college students was tested using path analysis. A total of 257 undergraduate students aged 18-24 years completed an online survey. The independent variables were measured using the Multidimensional Scale of Perceived Social Support, the Brief Students' Multidimensional Life Satisfaction Scale, the Brief COPE Inventory, the Positive Automatic Thoughts Questionnaire, and the Cognition Checklist-Anxiety. The outcome, anxiety, was measured using the Anxiety subscale of the 21-item Depression Anxiety and Stress Scale. Only negative thinking and maladaptive coping had a direct relationship with anxiety. Negative thinking was the strongest predictor of both maladaptive coping and anxiety. These findings suggest that helping undergraduates manage their anxiety by reducing their negative thinking is critical. Designing and testing interventions to decrease negative thinking in college students is recommended for future research. © 2015 Wiley Periodicals, Inc.

  12. The Structural Diversity of Carbohydrate Antigens of Selected Gram-Negative Marine Bacteria

    Directory of Open Access Journals (Sweden)

    Elena P. Ivanova

    2011-10-01

    Full Text Available Marine microorganisms have evolved for millions of years to survive in the environments characterized by one or more extreme physical or chemical parameters, e.g., high pressure, low temperature or high salinity. Marine bacteria have the ability to produce a range of biologically active molecules, such as antibiotics, toxins and antitoxins, antitumor and antimicrobial agents, and as a result, they have been a topic of research interest for many years. Among these biologically active molecules, the carbohydrate antigens, lipopolysaccharides (LPSs, O-antigens found in cell walls of Gram-negative marine bacteria, show great potential as candidates in the development of drugs to prevent septic shock due to their low virulence. The structural diversity of LPSs is thought to be a reflection of the ability for these bacteria to adapt to an array of habitats, protecting the cell from being compromised by exposure to harsh environmental stress factors. Over the last few years, the variety of structures of core oligosaccharides and O-specific polysaccharides from LPSs of marine microrganisms has been discovered. In this review, we discuss the most recently encountered structures that have been identified from bacteria belonging to the genera Aeromonas, Alteromonas, Idiomarina, Microbulbifer, Pseudoalteromonas, Plesiomonas and Shewanella of the Gammaproteobacteria phylum; Sulfitobacter and Loktanella of the Alphaproteobactera phylum and to the genera Arenibacter, Cellulophaga, Chryseobacterium, Flavobacterium, Flexibacter of the Cytophaga-Flavobacterium-Bacteroides phylum. Particular attention is paid to the particular chemical features of the LPSs, such as the monosaccharide type, non-sugar substituents and phosphate groups, together with some of the typifying traits of LPSs obtained from marine bacteria. A possible correlation is then made between such features and the environmental adaptations undertaken by marine bacteria.

  13. Negative ion formation in the scattering of state-selected NO+ on GaAs(110)

    International Nuclear Information System (INIS)

    Martin, J.S.; Greeley, J.N.; Morris, J.R.; Ferenchok, B.T.; Jacobs, D.C.

    1993-01-01

    A hyperthermal beam of state-selected NO + X 1 Σ + (v,j) impinges on a clean, well characterized GaAs(110) surface. The resulting two-electron transfer products NO-and O- are independently interrogated with a novel ion imaging technique as a function of NO + translational and vibrational energies. The products are shown to have different appearance thresholds, product translational energy distributions, and NO + vibrational energy dependencies. Most notably, vibrational energy is an order of magnitude more effective that translational energy in activating O- formation at a collision energy of 45 eV. The O- angular distribution exhibits a correlation with translational energy which is asymmetric about the surface normal. These results suggest that the probability of O- formation is dependent on the molecules point of impact with the GaAs (110) surface. The dynamical features of the NO + /GaAs(110) reaction will be discussed in terms of the three independent coordinates addressed in this experiment: the diatom internuclear separation, the molecule-surface distance, and the surface impact parameter

  14. Rare Earth Chalcogels NaLnSnS4 (Ln = Y, Gd, Tb) for Selective Adsorption of Volatile Hydrocarbons and Gases

    KAUST Repository

    Edhaim, Fatimah; Rothenberger, Alexander

    2017-01-01

    that the new materials have pores in the macro (above 50 nm) and meso (2–50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO2 over CH4 or H2. The notable adsorption capacity for toluene (NaYSnS4: 1108 mg·g–1; NaGdSn

  15. A Negative Selection Algorithm Based on Hierarchical Clustering of Self Set and its Application in Anomaly Detection

    Directory of Open Access Journals (Sweden)

    Wen Chen

    2011-08-01

    Full Text Available A negative selection algorithm based on the hierarchical clustering of self set HC-RNSA is introduced in this paper. Several strategies are applied to improve the algorithm performance. First, the self data set is replaced by the self cluster centers to compare with the detector candidates in each cluster level. As the number of self clusters is much less than the self set size, the detector generation efficiency is improved. Second, during the detector generation process, the detector candidates are restricted to the lower coverage space to reduce detector redundancy. In the article, the problem that the distances between antigens coverage to a constant value in the high dimensional space is analyzed, accordingly the Principle Component Analysis (PCA method is used to reduce the data dimension, and the fractional distance function is employed to enhance the distinctiveness between the self and non-self antigens. The detector generation procedure is terminated when the expected non-self coverage is reached. The theory analysis and experimental results demonstrate that the detection rate of HC-RNSA is higher than that of the traditional negative selection algorithms while the false alarm rate and time cost are reduced.

  16. Molecular evolution, characterization and expression analysis of SnRK2 gene family in Pak-choi (Brassica rapa ssp. chinensis

    Directory of Open Access Journals (Sweden)

    Zhinan eHuang

    2015-10-01

    Full Text Available Abstract: The sucrose non-fermenting 1-related protein kinase 2 (SnRK2 family members are plant-specific serine/threonine kinases that are involved in the plant response to abiotic stress and abscisic acid (ABA-dependent plant development. Further understanding of the evolutionary history and expression characteristics of these genes will help to elucidate the mechanisms of the stress tolerance in Pak-choi, an important green leafy vegetable in China. Thus, we investigated the evolutionary patterns, footprints and conservation of SnRK2 genes in selected plants and later cloned and analyzed SnRK2 genes in Pak-choi. We found that this gene family was preferentially retained in Brassicas after the Brassica-Arabidopsis thaliana split. Next, we cloned and sequenced 13 SnRK2 from both cDNA and DNA libraries of stress-induced Pak-choi, which were under conditions of ABA, salinity, cold, heat, and osmotic treatments. Most of the BcSnRK2s have eight exons and could be divided into three groups. The subcellular localization predictions suggested that the putative BcSnRK2 proteins were enriched in the nucleus. The results of an analysis of the expression patterns of the BcSnRK2 genes showed that BcSnRK2 group III genes were robustly induced by ABA treatments. Most of the BcSnRK2 genes were activated by low temperature, and the BcSnRK2.6 genes responded to both ABA and low temperature. In fact, most of the BcSnRK2 genes showed positive or negative regulation under ABA and low temperature treatments, suggesting that they may be global regulators that function at the intersection of multiple signaling pathways to play important roles in Pak-choi stress responses.

  17. A cytochrome P450 monooxygenase commonly used for negative selection in transgenic plants causes growth anomalies by disrupting brassinosteroid signaling

    Directory of Open Access Journals (Sweden)

    Manivasagam Sindhu

    2011-04-01

    Full Text Available Abstract Background Cytochrome P450 monooxygenases form a large superfamily of enzymes that catalyze diverse reactions. The P450SU1 gene from the soil bacteria Streptomyces griseolus encodes CYP105A1 which acts on various substrates including sulfonylurea herbicides, vitamin D, coumarins, and based on the work presented here, brassinosteroids. P450SU1 is used as a negative-selection marker in plants because CYP105A1 converts the relatively benign sulfonyl urea pro-herbicide R7402 into a highly phytotoxic product. Consistent with its use for negative selection, transgenic Arabidopsis plants were generated with P450SU1 situated between recognition sequences for FLP recombinase from yeast to select for recombinase-mediated excision. However, unexpected and prominent developmental aberrations resembling those described for mutants defective in brassinosteroid signaling were observed in many of the lines. Results The phenotypes of the most affected lines included severe stunting, leaf curling, darkened leaves characteristic of anthocyanin accumulation, delayed transition to flowering, low pollen and seed yields, and delayed senescence. Phenotype severity correlated with P450SU1 transcript abundance, but not with transcript abundance of other experimental genes, strongly implicating CYP105A1 as responsible for the defects. Germination and seedling growth of transgenic and control lines in the presence and absence of 24-epibrassinolide indicated that CYP105A1 disrupts brassinosteroid signaling, most likely by inactivating brassinosteroids. Conclusions Despite prior use of this gene as a genetic tool, deleterious growth in the absence of R7402 has not been elaborated. We show that this gene can cause aberrant growth by disrupting brassinosteroid signaling and affecting homeostasis.

  18. First-principles study of ZnSnAs2-based dilute magnetic semiconductors

    Science.gov (United States)

    Kizaki, Hidetoshi; Morikawa, Yoshitada

    2018-02-01

    The electronic structure and magnetic properties of chalcopyrite Zn(Sn,TM)As2 and (Zn,TM)SnAs2 have been investigated by the Korringa-Kohn-Rostoker method combined with the coherent potential approximation within the local spin density approximation, where TM denotes a 3d transition metal element. We find that the half-metallic and high-spin ferromagnetic state can be obtained in Zn(Sn,V)As2, Zn(Sn,Cr)As2, Zn(Sn,Mn)As2, (Zn,V)SnAs2, and (Zn,Cr)SnAs2. The calculated result of Zn(Sn,Mn)As2 is in good agreement with the experimentally observed room-temperature ferromagnetism if we can control selective Mn doping at Sn sites. In addition, (Zn,V)SnAs2 and (Zn,Cr)SnAs2 are predicted to exhibit high-Curie-temperature ferromagnetism.

  19. A cognitive-perceptual model of symptom perception in males and females: the roles of negative affect, selective attention, health anxiety and psychological job demands.

    Science.gov (United States)

    Goodwin, Laura; Fairclough, Stephen H; Poole, Helen M

    2013-06-01

    Kolk et al.'s model of symptom perception underlines the effects of trait negative affect, selective attention and external stressors. The current study tested this model in 263 males and 498 females from an occupational sample. Trait negative affect was associated with symptom reporting in females only, and selective attention and psychological job demands were associated with symptom reporting in both genders. Health anxiety was associated with symptom reporting in males only. Future studies might consider the inclusion of selective attention, which was more strongly associated with symptom reporting than negative affect. Psychological job demands appear to influence symptom reporting in both males and females.

  20. Characterization and process development for the selective removal of Sn, Sb, and As from anode slime obtained from electrolytic copper refining

    Directory of Open Access Journals (Sweden)

    Steinlechner S.

    2018-01-01

    Full Text Available The aim of this work was to develop a process for the removal of Sn, Sb and As from anode slime out of copper refinery to disburden a subsequent pyrometallurgical processing for precious metals refinement. For this reason, a detailed literature survey was conducted, followed by a characterization to find the present compounds/alloys and their morphology. A newly developed process concept for the separate extraction of the afore mentioned three target metals was developed and verified by leaching experiments, combined with thermodynamic calculations on their behavior under varying conditions. In this context, the influence of leaching temperature, alkalinity of leaching solution, and solid-liquid ration were evaluated on the extraction yields of Sn, As, and Sb, as well as how to exploit these findings to obtain separate streams enriched in the respective metals.

  1. Internal friction behavior of liquid Bi-Sn alloys

    International Nuclear Information System (INIS)

    Wu Aiqing; Guo Lijun; Liu Changsong; Jia Erguang; Zhu Zhengang

    2005-01-01

    Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480 - bar Cand another at about 830 - bar C. Only a single internal-friction peak at about 830 - bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids

  2. Internal friction behavior of liquid Bi-Sn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu Aiqing [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Guo Lijun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Liu Changsong [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Jia Erguang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Zhu Zhengang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China)]. E-mail: zgzhu@issp.ac.cn

    2005-12-01

    Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480{sup -}bar Cand another at about 830{sup -}bar C. Only a single internal-friction peak at about 830{sup -}bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids.

  3. BLACK AND HISPANIC IMMIGRANTS' RESILIENCE AGAINST NEGATIVE ABILITY RACIAL STEREOTYPES AT SELECTIVE COLLEGES AND UNIVERSITIES IN THE UNITED STATES*

    Science.gov (United States)

    Owens, Jayanti; Lynch, Scott M

    2012-10-01

    Stereotype threat is a widely supported theory for understanding the racial achievement gap in college grade performance. However, today's minority college students are increasingly of immigrant origins, and it is unclear whether two dispositional mechanisms that may increase susceptibility to stereotype threat are applicable to immigrants. We use survey data to examine whether and how negative ability stereotypes affect the grades of 1,865 first, second, and third generation or higher (domestic) minority students at 28 selective American colleges. Structural equation model results indicate that first generation immigrants are highly-resistant to both dispositional identity threat mechanisms we consider. Second generation immigrants experience only certain dispositional elements of identity threat. Drawing on research in social psychology, we suggest immigrants tend to resist stereotype threat in part due to the primacy of their immigrant identities and their connectedness to the opportunity structure of mainstream society.

  4. Reconstructed ancestral enzymes reveal that negative selection drove the evolution of substrate specificity in ADP-dependent kinases.

    Science.gov (United States)

    Castro-Fernandez, Víctor; Herrera-Morande, Alejandra; Zamora, Ricardo; Merino, Felipe; Gonzalez-Ordenes, Felipe; Padilla-Salinas, Felipe; Pereira, Humberto M; Brandão-Neto, Jose; Garratt, Richard C; Guixe, Victoria

    2017-09-22

    One central goal in molecular evolution is to pinpoint the mechanisms and evolutionary forces that cause an enzyme to change its substrate specificity; however, these processes remain largely unexplored. Using the glycolytic ADP-dependent kinases of archaea, including the orders Thermococcales , Methanosarcinales , and Methanococcales , as a model and employing an approach involving paleoenzymology, evolutionary statistics, and protein structural analysis, we could track changes in substrate specificity during ADP-dependent kinase evolution along with the structural determinants of these changes. To do so, we studied five key resurrected ancestral enzymes as well as their extant counterparts. We found that a major shift in function from a bifunctional ancestor that could phosphorylate either glucose or fructose 6-phosphate (fructose-6-P) as a substrate to a fructose 6-P-specific enzyme was started by a single amino acid substitution resulting in negative selection with a ground-state mode against glucose and a subsequent 1,600-fold change in specificity of the ancestral protein. This change rendered the residual phosphorylation of glucose a promiscuous and physiologically irrelevant activity, highlighting how promiscuity may be an evolutionary vestige of ancestral enzyme activities, which have been eliminated over time. We also could reconstruct the evolutionary history of substrate utilization by using an evolutionary model of discrete binary characters, indicating that substrate uses can be discretely lost or acquired during enzyme evolution. These findings exemplify how negative selection and subtle enzyme changes can lead to major evolutionary shifts in function, which can subsequently generate important adaptive advantages, for example, in improving glycolytic efficiency in Thermococcales . © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Single-Particle States in $^{133}$Sn

    CERN Multimedia

    Huck, A

    2002-01-01

    % IS338 \\\\ \\\\ It is suggested to investigate the $\\beta^- $-decay of $^{133}$In and $^{134}$In in order to determine the single-particle states in $^{133}$Sn, which are so far unknown and needed for the shell-model description of the region close to $^{132}$Sn. Large hyper-pure Ge-detectors will be used for the $\\gamma$-ray spectroscopy. In the experiments with $^{134}$In, delayed neutrons in coincidence with $\\gamma$-rays from excited states in $^{133}$Sn provide the opportunity for a very selective detection of the states in question.

  6. Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection.

    Science.gov (United States)

    Hegde, Shivanand; Hegde, Shrilakshmi; Zimmermann, Martina; Flöck, Martina; Spergser, Joachim; Rosengarten, Renate; Chopra-Dewasthaly, Rohini

    2015-07-01

    Mycoplasmas possess complex pathogenicity determinants that are largely unknown at the molecular level. Mycoplasma agalactiae serves as a useful model to study the molecular basis of mycoplasma pathogenicity. The generation and in vivo screening of a transposon mutant library of M. agalactiae were employed to unravel its host colonization factors. Tn4001mod mutants were sequenced using a novel sequencing method, and functionally heterogeneous pools containing 15 to 19 selected mutants were screened simultaneously through two successive cycles of sheep intramammary infections. A PCR-based negative selection method was employed to identify mutants that failed to colonize the udders and draining lymph nodes in the animals. A total of 14 different mutants found to be absent from ≥ 95% of samples were identified and subsequently verified via a second round of stringent confirmatory screening where 100% absence was considered attenuation. Using this criterion, seven mutants with insertions in genes MAG1050, MAG2540, MAG3390, uhpT, eutD, adhT, and MAG4460 were not recovered from any of the infected animals. Among the attenuated mutants, many contain disruptions in hypothetical genes, implying their previously unknown role in M. agalactiae pathogenicity. These data indicate the putative role of functionally different genes, including hypothetical ones, in the pathogenesis of M. agalactiae. Defining the precise functions of the identified genes is anticipated to increase our understanding of M. agalactiae infections and to develop successful intervention strategies against it. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. Identification of human triple-negative breast cancer subtypes and preclinical models for selection of targeted therapies

    Science.gov (United States)

    Lehmann, Brian D.; Bauer, Joshua A.; Chen, Xi; Sanders, Melinda E.; Chakravarthy, A. Bapsi; Shyr, Yu; Pietenpol, Jennifer A.

    2011-01-01

    Triple-negative breast cancer (TNBC) is a highly diverse group of cancers, and subtyping is necessary to better identify molecular-based therapies. In this study, we analyzed gene expression (GE) profiles from 21 breast cancer data sets and identified 587 TNBC cases. Cluster analysis identified 6 TNBC subtypes displaying unique GE and ontologies, including 2 basal-like (BL1 and BL2), an immunomodulatory (IM), a mesenchymal (M), a mesenchymal stem–like (MSL), and a luminal androgen receptor (LAR) subtype. Further, GE analysis allowed us to identify TNBC cell line models representative of these subtypes. Predicted “driver” signaling pathways were pharmacologically targeted in these cell line models as proof of concept that analysis of distinct GE signatures can inform therapy selection. BL1 and BL2 subtypes had higher expression of cell cycle and DNA damage response genes, and representative cell lines preferentially responded to cisplatin. M and MSL subtypes were enriched in GE for epithelial-mesenchymal transition, and growth factor pathways and cell models responded to NVP-BEZ235 (a PI3K/mTOR inhibitor) and dasatinib (an abl/src inhibitor). The LAR subtype includes patients with decreased relapse-free survival and was characterized by androgen receptor (AR) signaling. LAR cell lines were uniquely sensitive to bicalutamide (an AR antagonist). These data may be useful in biomarker selection, drug discovery, and clinical trial design that will enable alignment of TNBC patients to appropriate targeted therapies. PMID:21633166

  8. The NS3 proteins of global strains of bluetongue virus evolve into regional topotypes through negative (purifying) selection.

    Science.gov (United States)

    Balasuriya, U B R; Nadler, S A; Wilson, W C; Pritchard, L I; Smythe, A B; Savini, G; Monaco, F; De Santis, P; Zhang, N; Tabachnick, W J; Maclachlan, N J

    2008-01-01

    Comparison of the deduced amino acid sequences of the genes (S10) encoding the NS3 protein of 137 strains of bluetongue virus (BTV) from Africa, the Americas, Asia, Australia and the Mediterranean Basin showed limited variation. Common to all NS3 sequences were potential glycosylation sites at amino acid residues 63 and 150 and a cysteine at residue 137, whereas a cysteine at residue 181 was not conserved. The PPXY and PS/TAP late-domain motifs were conserved in all but three of the viruses. Phylogenetic analyses of these same sequences yielded two principal clades that grouped the viruses irrespective of their serotype or year of isolation (1900-2003). All viruses from Asia and Australia were grouped in one clade, whereas those from the other regions were present in both clades. Each clade segregated into distinct subclades that included viruses from single or multiple regions, and the S10 genes of some field viruses were identical to those of live-attenuated BTV vaccines. There was no evidence of positive selection on the S10 gene as assessed by reconstruction of ancestral codon states on the phylogeny, rather the functional constraints of the NS3 protein are expressed through substantial negative (purifying) selection.

  9. A high efficiency gene disruption strategy using a positive-negative split selection marker and electroporation for Fusarium oxysporum.

    Science.gov (United States)

    Liang, Liqin; Li, Jianqiang; Cheng, Lin; Ling, Jian; Luo, Zhongqin; Bai, Miao; Xie, Bingyan

    2014-11-01

    The Fusarium oxysporum species complex consists of fungal pathogens that cause serial vascular wilt disease on more than 100 cultivated species throughout the world. Gene function analysis is rapidly becoming more and more important as the whole-genome sequences of various F. oxysporum strains are being completed. Gene-disruption techniques are a common molecular tool for studying gene function, yet are often a limiting step in gene function identification. In this study we have developed a F. oxysporum high-efficiency gene-disruption strategy based on split-marker homologous recombination cassettes with dual selection and electroporation transformation. The method was efficiently used to delete three RNA-dependent RNA polymerase (RdRP) genes. The gene-disruption cassettes of three genes can be constructed simultaneously within a short time using this technique. The optimal condition for electroporation is 10μF capacitance, 300Ω resistance, 4kV/cm field strength, with 1μg of DNA (gene-disruption cassettes). Under these optimal conditions, we were able to obtain 95 transformants per μg DNA. And after positive-negative selection, the transformants were efficiently screened by PCR, screening efficiency averaged 85%: 90% (RdRP1), 85% (RdRP2) and 77% (RdRP3). This gene-disruption strategy should pave the way for high throughout genetic analysis in F. oxysporum. Copyright © 2014 Elsevier GmbH. All rights reserved.

  10. Determinação seletiva de tributilestanho na presença de Sn(IV em amostras ambientais usando HG-ICP OES e Saccharomyces cerevisiae como material sorvente Selective determination of tributyltin in the presence of Sn(IV in environmental samples using HG-ICP OES and Saccharomyces cerevisiae as sorbing material

    Directory of Open Access Journals (Sweden)

    Monizze Vannuci e Silva

    2010-01-01

    Full Text Available A method for selective determination of tributyltin in the presence of Sn(IV by combining hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP OES and solid phase extraction (SPE using baker's yeast is proposed. The procedure is based on selective retention of TBT by the yeast at pH = 6. Detection limit of 1.9 µg L-1 and quantification limit of 6.3 µg L-1 were obtained. TBT and San(IV were determined in the range of 0-25 µg L-1 and the proposed approach was applied to analyze river water, sea water and biological extracts, with recoveries of 114, 101 and 86%, respectively.

  11. An event-related brain potential study of visual selective attention to conjunctions of color and shape.

    Science.gov (United States)

    Smid, H G; Jakob, A; Heinze, H J

    1999-03-01

    What cognitive processes underlie event-related brain potential (ERP) effects related to visual multidimensional selective attention and how are these processes organized? We recorded ERPs when participants attended to one conjunction of color, global shape and local shape and ignored other conjunctions of these attributes in three discriminability conditions. Attending to color and shape produced three ERP effects: frontal selection positivity (FSP), central negativity (N2b), and posterior selection negativity (SN). The results suggested that the processes underlying SN and N2b perform independent within-dimension selections, whereas the process underlying the FSP performs hierarchical between-dimension selections. At posterior electrodes, manipulation of discriminability changed the ERPs to the relevant but not to the irrelevant stimuli, suggesting that the SN does not concern the selection process itself but rather a cognitive process initiated after selection is finished. Other findings suggested that selection of multiple visual attributes occurs in parallel.

  12. A bioinformatics approach for precision medicine off-label drug drug selection among triple negative breast cancer patients.

    Science.gov (United States)

    Cheng, Lijun; Schneider, Bryan P; Li, Lang

    2016-07-01

    Cancer has been extensively characterized on the basis of genomics. The integration of genetic information about cancers with data on how the cancers respond to target based therapy to help to optimum cancer treatment. The increasing usage of sequencing technology in cancer research and clinical practice has enormously advanced our understanding of cancer mechanisms. The cancer precision medicine is becoming a reality. Although off-label drug usage is a common practice in treating cancer, it suffers from the lack of knowledge base for proper cancer drug selections. This eminent need has become even more apparent considering the upcoming genomics data. In this paper, a personalized medicine knowledge base is constructed by integrating various cancer drugs, drug-target database, and knowledge sources for the proper cancer drugs and their target selections. Based on the knowledge base, a bioinformatics approach for cancer drugs selection in precision medicine is developed. It integrates personal molecular profile data, including copy number variation, mutation, and gene expression. By analyzing the 85 triple negative breast cancer (TNBC) patient data in the Cancer Genome Altar, we have shown that 71.7% of the TNBC patients have FDA approved drug targets, and 51.7% of the patients have more than one drug target. Sixty-five drug targets are identified as TNBC treatment targets and 85 candidate drugs are recommended. Many existing TNBC candidate targets, such as Poly (ADP-Ribose) Polymerase 1 (PARP1), Cell division protein kinase 6 (CDK6), epidermal growth factor receptor, etc., were identified. On the other hand, we found some additional targets that are not yet fully investigated in the TNBC, such as Gamma-Glutamyl Hydrolase (GGH), Thymidylate Synthetase (TYMS), Protein Tyrosine Kinase 6 (PTK6), Topoisomerase (DNA) I, Mitochondrial (TOP1MT), Smoothened, Frizzled Class Receptor (SMO), etc. Our additional analysis of target and drug selection strategy is also fully

  13. [Development and Evaluation of a New Selective Culture Medium, KBM Anaero RS-GNR, for Detection of Anaerobic Gram Negative Rods].

    Science.gov (United States)

    Narita, Taeko; Kato, Kyohei; Hanaiwa, Hiroki; Harada, Tetsuhiro; Funashima, Yumiko; Akiwa, Makoto; Sekiguchi, Jun-Ichiro; Nagasawa, Zenzo; Umemura, Tsukuru

    2017-03-22

    The laboratory culture methods for isolating drug-resistant pathogens has been the gold standard in medical microbiology, and play pivotal roles in the overall management of infectious diseases. Recently, several reports have emphasized the development of antibiotics-resistance among anaerobic gram-negative rods, especially Genus Bacteroides and Prevotella . Therefore, a selective culture method to detect these pathogens is needed. We developed here the new selective culture medium, termed "KBM Anaero RS-GNR," for detecting anaerobic Gram-negative rods. Growth capability and selectivity of the agar medium were assessed by using the pure culture suspensions of more than 100 bacterial strains as well as the 13 samples experimentally contaminated with these bacterial strains. This new medium, "KBM Anaero RS-GNR," successfully showed the selective isolation of anaerobic Gram-negative rods. Compared with commercially available medium, "PV Brucella HK Agar, " which is also designed to detect anaerobic Gram-negative rods, there was no significant difference of the overall detection efficiency between two media. However, "KBM Anaero RS-GNR" showed superior to selectivity for anaerobic Gram-negative rods, especially from the samples contaminated with Candida species. Thus, the culture method using KBM Anaero RS-GNR is relevant for isolation of anaerobic Gram-negative rods especially from clinical specimens.

  14. Pentaclethra macroloba tannins fractions active against methicillin-resistant staphylococcal and Gram-negative strains showing selective toxicity

    Directory of Open Access Journals (Sweden)

    Ivana Correa Ramos Leal

    2011-12-01

    Full Text Available The ethanol extract of the vegetal species Pentaclethra macroloba (Willd. Kuntze, Fabaceae, was fractioned and the antibacterial activity was determined. The active ethyl acetate (ea fraction showed activity against Gram-positive (Staphylococcus spp. and Enterococcus spp. and Gram-negative (Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella pneumoniae multiresistant bacteria. Gallic acid derivatives were identified as the main compounds in inactive subfractions from the ea fraction, while the active one afforded ellagic acid as the major constituent when submitted to acid hydrolysis reaction, which suggests the presence of hydrolysable tannins. The minimum bactericidal concentration analysis showed a bactericide mechanism of action for the tannin subfraction found. The antibacterial mechanism of action of the active tannin subfraction against S. aureus reference strains (ATCC 29213 e 33591 was proposed adopting an in vitro assay of protein synthesis inhibition. For this, bacterial cells were labeled with [35S] methionine in the presence of the subfraction. The protein synthesis inhibition was observed at 256 µg/mL of this subfraction. At this concentration it did not present cytotoxicity in eukaryotic cells by the neutral red technique, suggesting selective toxicity. The present study is the first in vitro investigation of the antibacterial properties of tannin fractions obtained from a polar extract of P. macroloba.

  15. Pentaclethra macroloba tannins fractions active against methicillin-resistant staphylococcal and Gram-negative strains showing selective toxicity

    Directory of Open Access Journals (Sweden)

    Ivana Correa Ramos Leal

    2011-08-01

    Full Text Available The ethanol extract of the vegetal species Pentaclethra macroloba (Willd. Kuntze, Fabaceae, was fractioned and the antibacterial activity was determined. The active ethyl acetate (ea fraction showed activity against Gram-positive (Staphylococcus spp. and Enterococcus spp. and Gram-negative (Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella pneumoniae multiresistant bacteria. Gallic acid derivatives were identified as the main compounds in inactive subfractions from the ea fraction, while the active one afforded ellagic acid as the major constituent when submitted to acid hydrolysis reaction, which suggests the presence of hydrolysable tannins. The minimum bactericidal concentration analysis showed a bactericide mechanism of action for the tannin subfraction found. The antibacterial mechanism of action of the active tannin subfraction against S. aureus reference strains (ATCC 29213 e 33591 was proposed adopting an in vitro assay of protein synthesis inhibition. For this, bacterial cells were labeled with [35S] methionine in the presence of the subfraction. The protein synthesis inhibition was observed at 256 µg/mL of this subfraction. At this concentration it did not present cytotoxicity in eukaryotic cells by the neutral red technique, suggesting selective toxicity. The present study is the first in vitro investigation of the antibacterial properties of tannin fractions obtained from a polar extract of P. macroloba.

  16. Thymic commitment of regulatory T cells is a pathway of TCR-dependent selection that isolates repertoires undergoing positive or negative selection.

    Science.gov (United States)

    Coutinho, A; Caramalho, I; Seixas, E; Demengeot, J

    2005-01-01

    The seminal work of Le Douarin and colleagues (Ohki et al. 1987; Ohki et al. 1988; Salaun et al. 1990; Coutinho et al. 1993) first demonstrated that peripheral tissue-specific tolerance is centrally established in the thymus, by epithelial stromal cells (TEC). Subsequent experiments have shown that TEC-tolerance is dominant and mediated by CD4 regulatory T cells (Treg) that are generated intrathymically by recognition of antigens expressed on TECs (Modigliani et al. 1995; Modigliani et al. 1996a). From these and other observations, in 1996 Modigliani and colleagues derived a general model for the establishment and maintenance of natural tolerance (MM96) (Modigliani et al. 1996b), with two central propositions: (1) T cell receptor (TCR)-dependent sorting of emergent repertoires generates TEC-specific Treg displaying the highest TCR self-affinities below deletion thresholds, thus isolating repertoires undergoing positive and negative selection; (2) Treg are intrathymically committed (and activated) for a unique differentiative pathway with regulatory effector functions. The model explained the embryonic/perinatal time window of natural tolerance acquisition, by developmental programs determining (1) TCR multireactivity, (2) the cellular composition in the thymic stroma (relative abundance of epithelial vs hemopoietic cells), and (3) the dynamics of peripheral lymphocyte pools, built by accumulation of recent thymic emigrants (RTE) that remain recruitable to regulatory functions. We discuss here the MM96 in the light of recent results demonstrating the promiscuous expression of tissue-specific antigens by medullary TECs (Derbinski et al. 2001; Anderson et al. 2002; Gotter et al. 2004) and indicating that Treg represent a unique differentiative pathway (Fontenot et al. 2003; Hori et al. 2003; Khattri et al. 2003), which is adopted by CD4 T cells with high avidity for TEC-antigens (Bensinger et al. 2001; Jordan et al. 2001; Apostolou et al. 2002). In the likelihood that

  17. Synthesis and characterization of poly-o-anisidine Sn(IV tungstate: A new and novel ‘organic–inorganic’ nano-composite material and its electro-analytical applications as Hg(II ion-selective membrane electrode

    Directory of Open Access Journals (Sweden)

    Asif A. Khan

    2012-07-01

    Full Text Available An organic–inorganic nano-composite poly-o-anisidine Sn(IV tungstate was chemically synthesized by sol–gel mixing of the incorporation of organic polymer o-anisidine into the matrices of inorganic ppt of Sn(IV tungstate in different mixing volume ratios. This composite material has been characterized using various analytical techniques like XRD (X-ray diffraction, FTIR (Fourier transform infrared, SEM (Scanning electron microscopy, TEM (Transmission electron microscopy and simultaneous TGA (Thermogravimetric analysis studies. On the basis of distribution studies, the material was found to be highly selective for Hg(II. Using this nano-composite cation exchanger as electro-active material, a new heterogeneous precipitate based on ion-sensitive membrane electrode was developed for the determination of Hg(II ions in solutions. The membrane electrode was mechanically stable, with a quick response time, and can be operated within a wide pH range. The electrode was also found to be satisfactory in electrometric titrations.

  18. Distinction of Gram-positive and -negative bacteria using a colorimetric microbial viability assay based on the reduction of water-soluble tetrazolium salts with a selection medium.

    Science.gov (United States)

    Tsukatani, Tadayuki; Suenaga, Hikaru; Higuchi, Tomoko; Shiga, Masanobu; Noguchi, Katsuya; Matsumoto, Kiyoshi

    2011-01-01

    Bacteria are fundamentally divided into two groups: Gram-positive and Gram-negative. Although the Gram stain and other techniques can be used to differentiate these groups, some issues exist with traditional approaches. In this study, we developed a method for differentiating Gram-positive and -negative bacteria using a colorimetric microbial viability assay based on the reduction of the tetrazolium salt {2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt} (WST-8) via 2-methyl-1,4-napthoquinone with a selection medium. We optimized the composition of the selection medium to allow the growth of Gram-negative bacteria while inhibiting the growth of Gram-positive bacteria. When the colorimetric viability assay was carried out in a selection medium containing 0.5µg/ml crystal violet, 5.0 µg/ml daptomycin, and 5.0µg/ml vancomycin, the reduction in WST-8 by Gram-positive bacteria was inhibited. On the other hand, Gram-negative bacteria produced WST-8-formazan in the selection medium. The proposed method was also applied to determine the Gram staining characteristics of bacteria isolated from various foodstuffs. There was good agreement between the results obtained using the present method and those obtained using a conventional staining method. These results suggest that the WST-8 colorimetric assay with selection medium is a useful technique for accurately differentiating Gram-positive and -negative bacteria.

  19. Study of rotational band in 111Sn

    International Nuclear Information System (INIS)

    Ganguly, S.; Banerjee, P.; Ray, I.; Kshetri, R.; Raut, R.; Goswami, A.; Saha Sarkar, M.; Bhattacharya, S.; Mukherjee, A.; Mukherjee, G.; Basu, S.K.; Mukhopadhyay, S.

    2006-01-01

    The motivation of the present work is to study the negative-parity rotational band in 111 Sn. Study of the lifetimes of the states of the rotational band is expected to provide information on their structures as well as the band termination phenomenon

  20. Improved methods in Agrobacterium-mediated transformation of almond using positive (mannose/pmi) or negative (kanamycin resistance) selection-based protocols.

    Science.gov (United States)

    Ramesh, Sunita A; Kaiser, Brent N; Franks, Tricia; Collins, Graham; Sedgley, Margaret

    2006-08-01

    A protocol for Agrobacterium-mediated transformation with either kanamycin or mannose selection was developed for leaf explants of the cultivar Prunus dulcis cv. Ne Plus Ultra. Regenerating shoots were selected on medium containing 15 muM kanamycin (negative selection), while in the positive selection strategy, shoots were selected on 2.5 g/l mannose supplemented with 15 g/l sucrose. Transformation efficiencies based on PCR analysis of individual putative transformed shoots from independent lines relative to the initial numbers of leaf explants tested were 5.6% for kanamycin/nptII and 6.8% for mannose/pmi selection, respectively. Southern blot analysis on six randomly chosen PCR-positive shoots confirmed the presence of the nptII transgene in each, and five randomly chosen lines identified to contain the pmi transgene by PCR showed positive hybridisation to a pmi DNA probe. The positive (mannose/pmi) and the negative (kanamycin) selection protocols used in this study have greatly improved transformation efficiency in almond, which were confirmed with PCR and Southern blot. This study also demonstrates that in almond the mannose/pmi selection protocol is appropriate and can result in higher transformation efficiencies over that of kanamycin/nptII selection protocols.

  1. Diethylstilbestrol alters positive and negative selection of T cells in the thymus and modulates T-cell repertoire in the periphery

    International Nuclear Information System (INIS)

    Brown, Nicole; Nagarkatti, Mitzi; Nagarkatti, Prakash S.

    2006-01-01

    Prenatal exposure to diethylstilbestrol (DES) is known to cause altered immune functions and increased susceptibility to autoimmune disease in humans. In the current study, we investigated the effects of DES on T-cell differentiation in the thymus using the HY-TCR transgenic (Tg) mouse model in which the female mice exhibit positive selection of T cells bearing the Tg TCR, while the male mice show negative selection of such T cells. In female HY-TCR-Tg mice, exposure to DES showed more pronounced decrease in thymic cellularity when compared to male mice. Additionally, female mice also showed a significant decrease in the proportion of double-positive (DP) T cells in the thymus and HY-TCR-specific CD8 + T cells in the periphery. Male mice exhibiting negative selection also showed decreased thymic cellularity following DES exposure. Moreover, the male mice showed increased proportion of double-negative (DN) T cells in the thymus and decreased proportion of CD8 + T cells. The density of expression of HY-TCR on CD8 + cells was increased following DES exposure in both females and males. Finally, the proliferative response of thymocytes to mitogens and peripheral lymph node T cells to male H-Y antigen was significantly altered in female and male mice following DES treatment. Taken together, these data suggest that DES alters T-cell differentiation in the thymus by interfering with positive and negative selection processes, which in turn modulates the T-cell repertoire in the periphery

  2. Microwave-Assisted Synthesis of Graphene-SnO2 Nanocomposites and Their Applications in Gas Sensors.

    Science.gov (United States)

    Kim, Hyoun Woo; Na, Han Gil; Kwon, Yong Jung; Kang, Sung Yong; Choi, Myung Sik; Bang, Jae Hoon; Wu, Ping; Kim, Sang Sub

    2017-09-20

    We obtained extremely high and selective sensitivity to NO 2 gas by fabricating graphene-SnO 2 nanocomposites using a commercial microwave oven. Structural characterization revealed that the products corresponded to agglomerated structures of graphene and SnO 2 particles, with small secondary SnO x (x ≤ 2) nanoparticles deposited on the surfaces. The overall oxygen atomic ratio was decreased with the appearance of an SnO x (x graphene-SnO 2 nanocomposites, with the graphene promoting efficient transport of the microwave energy, evaporation and redeposition of SnO x nanoparticles were facilitated. The graphene-SnO 2 nanocomposites exhibited a high sensor response of 24.7 for 1 ppm of NO 2 gas, at an optimized temperature of 150 °C. The graphene-SnO 2 nanocomposites were selectively sensitive to NO 2 gas, in comparison with SO 2 , NH 3 , and ethanol gases. We suggest that the generation of SnO x nanoparticles and the SnO x phase in the matrix results in the formation of SnO 2 /SnO 2 homojunctions, SnO 2 /SnO x (x graphene heterojunctions, which are responsible for the excellent sensitivity of the graphene-SnO 2 nanocomposites to NO 2 gas. In addition, the generation of surface Sn interstitial defects is also partly responsible for the excellent NO 2 sensing performance observed in this study.

  3. Electrochemical properties of Ti-Ni-Sn materials predicted by {sup 119}Sn Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ladam, A., E-mail: alix.ladam@univ-montp2.fr; Aldon, L.; Lippens, P.-E.; Olivier-Fourcade, J.; Jumas, J.-C. [Université de Montpellier, Institut Charles Gerhardt, UMR 5253 CNRS (France); Cenac-Morthe, C. [CNES, Service DCT/TV/El (France)

    2016-12-15

    The electrochemical activity of TiNiSn, TiNi {sub 2}Sn and Ti {sub 6}Sn {sub 5} compounds considered as negative electrode materials for Li-ion batteries has been predicted from the isomer shift- Hume-Rothery electronic density correlation diagram. The ternary compounds were obtained from solid-state reactions and Ti {sub 6}Sn {sub 5} by ball milling. The {sup 119}Sn Mössbauer parameters were experimentally determined and used to evaluate the Hume-Rothery electronic density [e {sub av}]. The values of [e {sub av}] are in the region of Li-rich Li-Sn alloys for Ti {sub 6}Sn {sub 5} and outside this region for the ternary compounds, suggesting that the former compound is electrochemically active but not the two latter ones. Electrochemical tests were performed for these different materials confirming this prediction. The close values of [e {sub av}] for Ti {sub 6}Sn {sub 5} and Li-rich Li-Sn alloys indicate that the observed good capacity retention could be related to small changes in the global structures during cycling.

  4. Selection of GP. Mur antigen-negative RBC for blood recipients with anti-'Mia ' records decreases transfusion reaction rates in Taiwan.

    Science.gov (United States)

    Yang, C-A; Lin, J-A; Chang, C-W; Wu, K-H; Yeh, S-P; Ho, C-M; Chang, J-G

    2016-10-01

    To evaluate the clinical significance of GP. Mur antigen-negative blood selection for transfusion in patients with anti-'Mi a ' records. The GP. Mur RBC phenotype is prevalent (7·3%) in Taiwan. Antibodies against GP. Mur (anti-'Mi a ') are identified in 1·24% of our population, and anti-'Mi a ' screening using GP. Mur RBC has been routine for Taiwan's blood banks. However, due to the lack of commercial antibodies, only cross-matching was used to prevent transfusion of GP. Mur-positive blood to patients with anti-'Mi a ' in most hospitals. There is still a risk of GP. Mur-positive RBC exposure and subsequent anti-'Mi a '-related transfusion reactions. Since February 2014, GP. Mur antigen-negative RBCs identified by reaction with anti-'Mi a '-positive serum were selected for blood recipients with anti-'Mi a ' records. The transfusion reactions between January 2013 and January 2014 were compared with those that occurred between February 2014 and July 2015. The transfusion reaction rate was significantly higher in anti-'Mi a '-positive blood recipients compared to total subjects receiving an RBC transfusion before GP. Mur-negative donor RBC selection. After antigen-negative RBC selection, the transfusion reaction frequency in subjects with anti-'Mi a ' became similar to total blood recipients. IgG form anti-'Mi a ' antibodies were present in all cases of probable anti-'Mi a '-related transfusion reactions. The time required for anti-'Mi a ' boosting after transfusion was around 4-21 days. Selection of GP. Mur-negative RBC for transfusion to patients with anti-'Mi a ' records could decrease the rate of transfusion reaction and antibody boosting. This procedure should be incorporated into blood bank routines in areas where anti-'Mi a ' is prevalent. © 2016 British Blood Transfusion Society.

  5. Whisker and Hillock formation on Sn, Sn-Cu and Sn-Pb electrodeposits

    International Nuclear Information System (INIS)

    Boettinger, W.J.; Johnson, C.E.; Bendersky, L.A.; Moon, K.-W.; Williams, M.E.; Stafford, G.R.

    2005-01-01

    High purity bright Sn, Sn-Cu and Sn-Pb layers, 3, 7 and 16 μm thick were electrodeposited on phosphor bronze cantilever beams in a rotating disk apparatus. Beam deflection measurements within 15 min of plating proved that all electrodeposits had in-plane compressive stress. In several days, the surfaces of the Sn-Cu deposits, which have the highest compressive stress, develop 50 μm contorted hillocks and 200 μm whiskers, pure Sn deposits develop 20 μm compact conical hillocks, and Sn-Pb deposits, which have the lowest compressive stress, remain unchanged. The differences between the initial compressive stresses for each alloy and pure Sn is due to the rapid precipitation of Cu 6 Sn 5 or Pb particles, respectively, within supersaturated Sn grains produced by electrodeposition. Over longer time, analysis of beam deflection measurements indicates that the compressive stress is augmented by the formation of Cu 6 Sn 5 on the bronze/Sn interface, while creep of the electrodeposit tends to decrease the compressive stress. Uniform creep occurs for Sn-Pb because it has an equi-axed grain structure. Localized creep in the form of hillocks and whiskers occurs for Sn and Sn-Cu because both have columnar structures. Compact hillocks form for the Sn deposits because the columnar grain boundaries are mobile. Contorted hillocks and whiskers form for the Sn-Cu deposits because the columnar grain boundary motion is impeded

  6. Dimensional stability of Ti--6Al--6V--2Sn

    International Nuclear Information System (INIS)

    Rack, H.J.

    1978-08-01

    The dimensional stability of Ti-6Al-6V-2Sn has been examined. It is shown that in the duplex annealed condition Ti-6Al-6V-2Sn is dimensionally stable at temperatures up to 448 0 K for 512 hrs. Solution treated Ti-6Al-6V-2Sn undergoes large dimensional changes during both initial aging between 673 and 973 0 K and subsequent exposure to low temperatures ( 0 K). These results indicate that if close dimensional tolerances must be maintained, duplex annealed Ti-6Al-6V-2Sn should be selected. Selection of treated and aged Ti-6Al-6V-2Sn should only be considered if accompanied by full scale environmental testing

  7. SNF1-related protein kinases 2 are negatively regulated by a plant-specific calcium sensor.

    Science.gov (United States)

    Bucholc, Maria; Ciesielski, Arkadiusz; Goch, Grażyna; Anielska-Mazur, Anna; Kulik, Anna; Krzywińska, Ewa; Dobrowolska, Grażyna

    2011-02-04

    SNF1-related protein kinases 2 (SnRK2s) are plant-specific enzymes involved in environmental stress signaling and abscisic acid-regulated plant development. Here, we report that SnRK2s interact with and are regulated by a plant-specific calcium-binding protein. We screened a Nicotiana plumbaginifolia Matchmaker cDNA library for proteins interacting with Nicotiana tabacum osmotic stress-activated protein kinase (NtOSAK), a member of the SnRK2 family. A putative EF-hand calcium-binding protein was identified as a molecular partner of NtOSAK. To determine whether the identified protein interacts only with NtOSAK or with other SnRK2s as well, we studied the interaction of an Arabidopsis thaliana orthologue of the calcium-binding protein with selected Arabidopsis SnRK2s using a two-hybrid system. All kinases studied interacted with the protein. The interactions were confirmed by bimolecular fluorescence complementation assay, indicating that the binding occurs in planta, exclusively in the cytoplasm. Calcium binding properties of the protein were analyzed by fluorescence spectroscopy using Tb(3+) as a spectroscopic probe. The calcium binding constant, determined by the protein fluorescence titration, was 2.5 ± 0.9 × 10(5) M(-1). The CD spectrum indicated that the secondary structure of the protein changes significantly in the presence of calcium, suggesting its possible function as a calcium sensor in plant cells. In vitro studies revealed that the activity of SnRK2 kinases analyzed is inhibited in a calcium-dependent manner by the identified calcium sensor, which we named SCS (SnRK2-interacting calcium sensor). Our results suggest that SCS is involved in response to abscisic acid during seed germination most probably by negative regulation of SnRK2s activity.

  8. The selective glycine uptake inhibitor org 25935 as an adjunctive treatment to atypical antipsychotics in predominant persistent negative symptoms of schizophrenia: results from the GIANT trial.

    Science.gov (United States)

    Schoemaker, Joep H; Jansen, Wim T; Schipper, Jacques; Szegedi, Armin

    2014-04-01

    Using a selective glycine uptake inhibitor as adjunctive to second-generation antipsychotic (SGA) was hypothesized to ameliorate negative and/or cognitive symptoms in subjects with schizophrenia. Subjects with predominant persistent negative symptoms (previously stabilized ≥3 months on an SGA) were enrolled in a randomized, placebo-controlled trial to investigate adjunctive treatment with Org 25935, a selective inhibitor of type 1 glycine transporter, over 12 weeks in a flexible dose design. Org 25935 was tested at 4 to 8 mg twice daily and 12 to 16 mg twice daily versus placebo. Primary efficacy outcome was mean change from baseline in Scale for Assessment of Negative Symptoms composite score. Secondary efficacy end points were Positive and Negative Syndrome Scale total and subscale scores, depressive symptoms (Calgary Depression Scale for Schizophrenia), global functioning (Global Assessment of Functioning scale), and cognitive measures using a computerized battery (Central Nervous System Vital Signs). Responder rates were assessed post hoc. A total of 215 subjects were randomized, of which 187 (87%) completed the trial. Both dose groups of Org 25935 did not differ significantly from placebo on Scale for Assessment of Negative Symptoms, Positive and Negative Syndrome Scale (total or subscale scores), Global Assessment of Functioning, or the majority of tested cognitive domains. Org 25935 was generally well tolerated within the tested dose range, with no meaningful effects on extrapyramidal symptoms and some reports of reversible visual adverse effects. Org 25935 did not differ significantly from placebo in reducing negative symptoms or improving cognitive functioning when administered as adjunctive treatment to SGA. In our study population, Org 25935 appeared to be well tolerated in the tested dose ranges.

  9. Cyberbullying as a negative result of cyber-culture of Slovak children and adolescents: selected research findings

    Directory of Open Access Journals (Sweden)

    Hollá Katarína

    2016-05-01

    Full Text Available Cyber-culture points out the life in cyberspace and goes beyond national cultures. It is particularly attractive for the young people who use Information and Communications Technologies (ICT to express their attitudes, values, beliefs and thinking. Those do not need to be necessarily in accordance with the standards of an individual society. Cyberculture becomes dangerous. Great risk lies in cyberbullying that represents negative impact of cyber-culture on human behavior. The aim of the study is to detect cyberbullying as a negative impact of cyber-culture among of Slovak children and adolescents. The research was carried out on a sample of 1619 11-18-year old respondents (average age was 14.51. Results of cyberbullying research carried out using Latent Class Analysis (LCA have proved the appropriateness of 3-latent-class module. Relative entropy of the module reached 0.915. It was demonstrated that 52.9% of respondents belonged to the group of uninvolved, 42.7% were victims and 4.4% were victims-aggressors. Being a negative consequence of cyber-culture, cyberbullying is a challenge that educators - including other assisting professions - face when educating children and adolescents to orientate in cyberspace, behave responsibly, express themselves in a way that would not interfere others’ integrity and identity (personal and virtual. The study was written under VEGA MŠVVaŠ SR a SAV č. 1/0244/15: “Detekcia a riešenie kyberšikany”.

  10. SN 2009E

    DEFF Research Database (Denmark)

    Pastorello...[], A.; Pumo, M.L.; Navasardyan, H.

    2012-01-01

    . In this paper we investigate the properties of SN 2009E, which exploded in a relatively nearby spiral galaxy (NGC 4141) and that is probably the faintest 1987A-like supernova discovered so far. We also attempt to characterize this subgroup of core-collapse supernovae with the help of the literature and present...... observations which started about 2 months after the supernova explosion, highlight significant differences between SN 2009E and the prototypical SN 1987A. Modelling the data of SN 2009E allows us to constrain the explosion parameters and the properties of the progenitor star, and compare the inferred estimates...... 2009E ejected about 0.04 M⊙ of 56Ni, which is the smallest 56Ni mass in our sample of 1987A-like events. Modelling the observations with a radiation hydrodynamics code, we infer for SN 2009E a kinetic plus thermal energy of about 0.6 foe, an initial radius of ~7 × 1012 cm and an ejected mass of ~19 M...

  11. Synthesis of Pt{sub 75}Sn{sub 25}/SnO{sub 2}/CNT nanoscaled electrode: Low onset potential of ethanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Tabet-Aoul, Amel [Institut National de la Recherche Scientifique (INRS)-Énergie, Matériaux et Télécommunications (EMT), 1650 Boulevard Lionel Boulet, Varennes, Québec, Canada J3X 1S2 (Canada); Mohamedi, Mohamed, E-mail: mohamedi@emt.inrs.ca [Institut National de la Recherche Scientifique (INRS)-Énergie, Matériaux et Télécommunications (EMT), 1650 Boulevard Lionel Boulet, Varennes, Québec, Canada J3X 1S2 (Canada)

    2013-03-15

    Highlights: ► A pulsed laser synthesis is used for the deposition of Pt, SnO{sub 2} and PtSn alloy thin films onto carbon nanotubes. ► These nanoscaled materials were characterized by FESEM, TEM, XRD and XPS. ► Enhanced electrocatalytic properties toward ethanol oxidation. -- Abstract: With the objective of lowering the potential oxidation of ethanol at PtSn nanocatalyst, we present the synthesis of free-standing catalyst layer comprising a current collector/carbon nanotubes (catalyst support)/SnO{sub 2}/Pt{sub 75}Sn{sub 25} (catalyst) nanostructured layers, each layer constructed upon the one below it. The CNTs are grown by chemical vapor deposition (CVD), whereas SnO{sub 2} and Pt{sub 75}Sn{sub 25} are synthesized by pulsed laser deposition and cross-beam laser deposition, respectively. FESEM revealed that Pt{sub 75}Sn{sub 25} nanoparticles assemble into cauliflower-like arrangement. TEM and HR-TEM showed that the Pt{sub 75}Sn{sub 25} layer thickness is of ca. 25 nm with a particle mean diameter of 4.3 nm. It was found that addition of SnO{sub 2} to Pt{sub 75}Sn{sub 25} promotes significantly the oxidation of ethanol at Pt{sub 75}Sn{sub 25} nanoparticles relative to a carbon nanotubes support. Indeed, the electrooxidation of ethanol at CNTs/SnO{sub 2}/Pt{sub 75}Sn{sub 25} electrode starts at about 100 mV negative with respect to that at CNT/Pt{sub 75}Sn{sub 25}. This decreased overpotential required to oxidize ethanol is very significant and has profound implications to developing high performing anodes for direct ethanol fuel cells technology.

  12. Diethylstilbestrol alters positive and negative selection of T cells in the thymus and modulates T-cell repertoire in the periphery

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Nicole [Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298 (United States); Nagarkatti, Mitzi [Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298 (United States); Nagarkatti, Prakash S [Department of Pharmacology and Toxicology, PO Box 980613, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0613 (United States)

    2006-04-15

    Prenatal exposure to diethylstilbestrol (DES) is known to cause altered immune functions and increased susceptibility to autoimmune disease in humans. In the current study, we investigated the effects of DES on T-cell differentiation in the thymus using the HY-TCR transgenic (Tg) mouse model in which the female mice exhibit positive selection of T cells bearing the Tg TCR, while the male mice show negative selection of such T cells. In female HY-TCR-Tg mice, exposure to DES showed more pronounced decrease in thymic cellularity when compared to male mice. Additionally, female mice also showed a significant decrease in the proportion of double-positive (DP) T cells in the thymus and HY-TCR-specific CD8{sup +} T cells in the periphery. Male mice exhibiting negative selection also showed decreased thymic cellularity following DES exposure. Moreover, the male mice showed increased proportion of double-negative (DN) T cells in the thymus and decreased proportion of CD8{sup +} T cells. The density of expression of HY-TCR on CD8{sup +} cells was increased following DES exposure in both females and males. Finally, the proliferative response of thymocytes to mitogens and peripheral lymph node T cells to male H-Y antigen was significantly altered in female and male mice following DES treatment. Taken together, these data suggest that DES alters T-cell differentiation in the thymus by interfering with positive and negative selection processes, which in turn modulates the T-cell repertoire in the periphery.

  13. Polarographic determination of Sn (II) and total Sn in PYRO and MDP radiopharmaceutical kits

    International Nuclear Information System (INIS)

    Sebastian, Maria V.A.; Lugon, Marcelo Di M.V.; Silva, Jose L. da; Fukumori, Neuza T.O.; Pereira, Nilda P.S. de; Silva, Constancia P.G. da; Matsuda, Margareth M.N.

    2007-01-01

    A sensitive, alternative method to atom absorption spectrometry, fluorimetry or potentiometry for the evaluation of tin(II) ions (0.1- 10 mg) and total tin in radiopharmaceutical kits was investigated. Differential pulse polarography was chosen. The supporting electrolyte was H 2 SO 4 3 mol L -1 and HCl 3 mol L -1 solution. The potential was swept from -250 to -800 mV vs Ag/AgCl/saturated KCl, using a dropping mercury electrode with 1 s drop time, 50 mV s -1 scan rate, -50 mV pulse amplitude, 40 ms pulse time and 10 mV step amplitude. Pure nitrogen was used to deaerate the polarographic cell solution for 5 min, before and after each sample introduction. Oxidation of Sn(II) was made in the same sample vial by adding H 2 O 2 (hydrogen peroxide) 10 mol L -1 , at 37 deg C, in order to quantify the total Sn. The calibration curve for Sn(II) and Sn(IV) was obtained in the concentration range of 0-10 ppm from a 1000 ppm standard solution. The detection limit of Sn(II) is 0.5 ppm and for Sn(IV) is 0.6 ppm. Differential pulse polarography was performed in the pyrophosphate (PYRO) and methylenediphosphonic acid (MDP) radiopharmaceutical kits, containing 2 mg and 1 mg of SnCl 2 .2H 2 O per vial, respectively. The described method for determination of stannous ion (Sn(II)), is selective, reproducible and adequate to be used in the quality control of lyophilized reagents and it shall be performed for other cold kits produced at IPEN. (author)

  14. Transport and NMR characteristics of the skutterudite-related compound Ca3Rh4Sn13

    Science.gov (United States)

    Tseng, C. W.; Kuo, C. N.; Li, B. S.; Wang, L. M.; Gippius, A. A.; Kuo, Y. K.; Lue, C. S.

    2018-02-01

    We report the electronic properties of the Yb3Rh4Sn13-type single crystalline Ca3Rh4Sn13 by means of the electrical resistivity, Hall coefficient, Seebeck coefficient, thermal conductivity, as well as 119Sn nuclear magnetic resonance (NMR) measurements. The negative sign of the Hall coefficient and Seebeck coefficient at low temperatures suggests that the n-type carriers dominate the electrical transport in Ca3Rh4Sn13, in contrast to the observations in Sr3Rh4Sn13 which has a p-type conduction. Such a finding indicates a significant difference in the electronic features between these two stannides. Furthermore, we analyzed the temperature-dependent 119Sn NMR spin-lattice relaxation rate for Ca3Rh4Sn13, (Sr0.7Ca0.3)3Rh4Sn13, and Sr3Rh4Sn13 to examine the change of the electronic Fermi-level density of states (DOS) in (Sr1-xCax)3Rh4Sn13. It indicates that the Sn 5s partial Fermi-level DOS enhances with increasing the Ca content, being consistent with the trend of the superconducting temperature. Since the total Fermi-level DOS usually obeys the same trend of the partial Fermi-level DOS, the NMR analysis provides microscopic evidence for the correlation between the electronic DOS and superconductivity of the (Sr1-xCax)3Rh4Sn13 system.

  15. α-Eleostearic acid-containing triglycerides for a continuous assay to determine lipase sn-1 and sn-3 regio-preference.

    Science.gov (United States)

    El Alaoui, Meddy; Soulère, Laurent; Noiriel, Alexandre; Queneau, Yves; Abousalham, Abdelkarim

    2017-08-01

    Lipases are essentially described as sn-1 and sn-3 regio-selective. Actually few methods are available to measure this lipase regio-selectivity, moreover they require chiral chromatography analysis or specific derivations which are discontinuous and time consuming. In this study we describe a new, convenient, sensitive and continuous spectrophotometric method to screen lipases regio-selectivity using synthetic triglycerides (TG) containing α-eleostearic acid (9Z, 11E, 13E-octadecatrienoic acid) either at the sn-1 position [1-α-eleostearoyl-2,3-octadecyl-sn-glycerol (sn-EOO)] or at the sn-3 position [1,2-octadecyl-3-α-eleostearoyl-sn-glycerol (sn-OOE)] and coated onto the wells of microtiter plates. A non-hydrolysable ether bond, with a non UV-absorbing alkyl chain, was introduced at the other sn positions to prevent acyl chain migration during TG synthesis or lipolysis. The synthesis of TG containing α-eleostearic acid was performed from S-glycidol in six steps to obtain sn-EOO and in five steps to sn-OOE. The α-eleostearic acid conjugated triene constitutes an intrinsic chromophore and, consequently, confers the strong UV absorption properties of this free fatty acid as well as of the TG harboring it. The lipase activity on coated sn-EOO or sn-OOE was measured by the increase in the absorbance at 272nm due to the transition of α-eleostearic acid from the adsorbed to the soluble state. Human and porcine pancreatic lipases, guinea pig pancreatic lipase related protein 2, Thermomyces lanuginosus lipase, Candida antarctica lipase A and Candida antarctica lipase B were all used to validate the assay. This continuous high-throughput screening method could determine directly without any processes after lipolysis the regio-selectivity of various lipases. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Factors in selecting serum samples for use in determining the positive/negative threshold (cut-off) in ELISA

    International Nuclear Information System (INIS)

    Jacobson, R.H.

    1998-01-01

    The threshold (cut-off) that defines whether a test result is seropositive or seronegative is calculated by testing serum samples from a subpopulation of animals that is assumed to represent the target population in all aspects. For this proposition to be true, it is essential to consider the variables in the target population that must be represented in the subpopulation. Without representation of the variables in the subpopulation, it is likely that the cut-off selected for the test will be errant and will misclassify animals as to their infection status. The purpose of this paper is to identify a few of the principal variables that need to be taken into account when selecting a subpopulation of animals for test validation. (author)

  17. Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection

    OpenAIRE

    Hegde, Shivanand; Hegde, Shrilakshmi; Zimmermann, Martina; Flöck, Martina; Spergser, Joachim; Rosengarten, Renate; Chopra-Dewasthaly, Rohini

    2015-01-01

    Mycoplasmas possess complex pathogenicity determinants that are largely unknown at the molecular level. Mycoplasma agalactiae serves as a useful model to study the molecular basis of mycoplasma pathogenicity. The generation and in vivo screening of a transposon mutant library of M. agalactiae were employed to unravel its host colonization factors. Tn4001mod mutants were sequenced using a novel sequencing method, and functionally heterogeneous pools containing 15 to 19 selected mutants were sc...

  18. Why Does Romania Have a Negative Selection in Parliamentary Elections? An Analysis of the Recruitment and Selection System During the Last Three Legislative Terms

    Directory of Open Access Journals (Sweden)

    Ioana MUNTEAN

    2016-06-01

    Full Text Available This paper considers theoretical perspectives on the recruitment and selection of political party candidates, in order to analyze the recruitment and selection process of Romanian MPs during the last three legislative terms. The Romanian proportional closed-list electoral system was replaced in 2008 by a majoritarian one, with single-member districts. In the wake of this change, party selectorates have loosened the admission criteria for candidates in parliamentary elections. Selectorates started considering candidates mostly because of their financial power and notoriety, while their education was overlooked. Our analysis shows that the quality of MPs’ diplomas has decreased significantly since 2008. Romanian MPs complete their education, most frequently technical, with MA or PhD degrees. Some get a second BA in fields complementary to their activity in Parliament – such as political, administrative or social sciences. These courses are usually taken later in life, at private universities, which are characterized by easy admission and graduation. Since there is no general rule for submitting their CVs, some MPs omit mentioning the information regarding the educational bodies that issued their diplomas. Romania continues to be characterized by a heterogeneous parliamentarian elite, as opposed to solid democracies, where the elite is formed in renowned universities. The latter also share a common background and are thus rather homogenous. We consider that a successful political reform in Romania should start within the party selectorates and their selection criteria of candidates for parliamentary elections.

  19. THE PRODUCTION RATE OF SN Ia EVENTS IN GLOBULAR CLUSTERS

    International Nuclear Information System (INIS)

    Washabaugh, Pearce C.; Bregman, Joel N.

    2013-01-01

    In globular clusters, dynamical evolution produces luminous X-ray emitting binaries at a rate about 200 times greater than in the field. If globular clusters also produce SN Ia at a high rate, it would account for many of the SN Ia production in early-type galaxies and provide insight into their formation. Here we use archival Hubble Space Telescope (HST) images of nearby galaxies that have hosted an SN Ia to examine the rate at which globular clusters produce these events. The location of the SN Ia is registered on an HST image obtained before the event or after the supernova (SN) faded. Of the 36 nearby galaxies examined, 21 had sufficiently good data to search for globular cluster hosts. None of the 21 SNe have a definite globular cluster counterpart, although there are some ambiguous cases. This places an upper limit to the enhancement rate of SN Ia production in globular clusters of about 42 at the 95% confidence level, which is an order of magnitude lower than the enhancement rate for luminous X-ray binaries. Even if all of the ambiguous cases are considered as having a globular cluster counterpart, the upper bound for the enhancement rate is 82 at the 95% confidence level, still a factor of several below that needed to account for half of the SN Ia events. Barring unforeseen selection effects, we conclude that globular clusters are not responsible for producing a significant fraction of the SN Ia events in early-type galaxies.

  20. Optimal classifier selection and negative bias in error rate estimation: an empirical study on high-dimensional prediction

    Directory of Open Access Journals (Sweden)

    Boulesteix Anne-Laure

    2009-12-01

    Full Text Available Abstract Background In biometric practice, researchers often apply a large number of different methods in a "trial-and-error" strategy to get as much as possible out of their data and, due to publication pressure or pressure from the consulting customer, present only the most favorable results. This strategy may induce a substantial optimistic bias in prediction error estimation, which is quantitatively assessed in the present manuscript. The focus of our work is on class prediction based on high-dimensional data (e.g. microarray data, since such analyses are particularly exposed to this kind of bias. Methods In our study we consider a total of 124 variants of classifiers (possibly including variable selection or tuning steps within a cross-validation evaluation scheme. The classifiers are applied to original and modified real microarray data sets, some of which are obtained by randomly permuting the class labels to mimic non-informative predictors while preserving their correlation structure. Results We assess the minimal misclassification rate over the different variants of classifiers in order to quantify the bias arising when the optimal classifier is selected a posteriori in a data-driven manner. The bias resulting from the parameter tuning (including gene selection parameters as a special case and the bias resulting from the choice of the classification method are examined both separately and jointly. Conclusions The median minimal error rate over the investigated classifiers was as low as 31% and 41% based on permuted uninformative predictors from studies on colon cancer and prostate cancer, respectively. We conclude that the strategy to present only the optimal result is not acceptable because it yields a substantial bias in error rate estimation, and suggest alternative approaches for properly reporting classification accuracy.

  1. SN 2012fr

    DEFF Research Database (Denmark)

    Contreras, Carlos; Phillips, M. M.; Burns, Christopher R.

    2018-01-01

    We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from -12 to +140 days with respect to the epo...

  2. Comparison of the electrochemical performance of mesoscopic Cu2Sb, SnSb and Sn/SnSb alloy powders

    International Nuclear Information System (INIS)

    Zhang Ge; Huang Kelong; Liu Suqin; Zhang Wei; Gong Benli

    2006-01-01

    Cu 2 Sb, SnSb and Sn/SnSb mesoscopic alloy powders were prepared by chemical reduction, respectively. The crystal structures and particle morphology of Cu 2 Sb, SnSb and Sn/SnSb were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The electrochemical performances of the Cu 2 Sb, SnSb and Sn/SnSb electrodes were investigated by galvanostatic charge and discharge cycling and electrochemical impedance spectroscopy (EIS). The results showed the first charge and discharge capacities of SnSb and Sn/SnSb were higher than Cu 2 Sb, but after 15 cycles, the charge capacity fading rates of Cu 2 Sb, Sn/SnSb and Sn/SnSb were 26.16%, 55.33% and 47.39%, respectively. Cu 2 Sb had a better cycle performance, and Sn/SnSb multiphase alloy was prior to pure SnSb due to the existence of excessive Sn in Sn/SnSb system

  3. Hierarchical ZnO Nanowires-loaded Sb-doped SnO2-ZnO Micrograting Pattern via Direct Imprinting-assisted Hydrothermal Growth and Its Selective Detection of Acetone Molecules

    Science.gov (United States)

    Choi, Hak-Jong; Choi, Seon-Jin; Choo, Soyoung; Kim, Il-Doo; Lee, Heon

    2016-01-01

    We propose a novel synthetic route by combining imprinting transfer of a Sb-doped SnO2 (ATO)-ZnO composite micrograting pattern (MP), i.e., microstrip lines, on a sensor substrate and subsequent hydrothermal growth of ZnO nanowires (NWs) for producing a hierarchical ZnO NW-loaded ATO-ZnO MP as an improved chemo-resistive sensing layer. Here, ATO-ZnO MP structure with 3-μm line width, 9-μm pitch, and 6-μm height was fabricated by direct transfer of mixed ATO and ZnO nanoparticle (NP)-dispersed resists, which are pre-patterned on a polydimethylsiloxane (PDMS) mold. ZnO NWs with an average diameter of less than 50 nm and a height of 250 nm were quasi-vertically grown on the ATO-ZnO MP, leading to markedly enhanced surface area and heterojunction composites between each ATO NP, ZnO NP, and ZnO NW. A ZnO NW-loaded MP sensor with a relative ratio of 1:9 between ATO and ZnO (1:9 ATO-ZnO), exhibited highly sensitive and selective acetone sensing performance with 2.84-fold higher response (Rair/Rgas = 12.8) compared to that (Rair/Rgas = 4.5) of pristine 1:9 ATO-ZnO MP sensor at 5 ppm. Our results demonstrate the processing advantages of direct imprinting-assisted hydrothermal growth for large-scale homogeneous coating of hierarchical oxide layers, particularly for applications in highly sensitive and selective chemical sensors.

  4. A methodology to design heuristics for model selection based on the characteristics of data: Application to investigate when the Negative Binomial Lindley (NB-L) is preferred over the Negative Binomial (NB).

    Science.gov (United States)

    Shirazi, Mohammadali; Dhavala, Soma Sekhar; Lord, Dominique; Geedipally, Srinivas Reddy

    2017-10-01

    Safety analysts usually use post-modeling methods, such as the Goodness-of-Fit statistics or the Likelihood Ratio Test, to decide between two or more competitive distributions or models. Such metrics require all competitive distributions to be fitted to the data before any comparisons can be accomplished. Given the continuous growth in introducing new statistical distributions, choosing the best one using such post-modeling methods is not a trivial task, in addition to all theoretical or numerical issues the analyst may face during the analysis. Furthermore, and most importantly, these measures or tests do not provide any intuitions into why a specific distribution (or model) is preferred over another (Goodness-of-Logic). This paper ponders into these issues by proposing a methodology to design heuristics for Model Selection based on the characteristics of data, in terms of descriptive summary statistics, before fitting the models. The proposed methodology employs two analytic tools: (1) Monte-Carlo Simulations and (2) Machine Learning Classifiers, to design easy heuristics to predict the label of the 'most-likely-true' distribution for analyzing data. The proposed methodology was applied to investigate when the recently introduced Negative Binomial Lindley (NB-L) distribution is preferred over the Negative Binomial (NB) distribution. Heuristics were designed to select the 'most-likely-true' distribution between these two distributions, given a set of prescribed summary statistics of data. The proposed heuristics were successfully compared against classical tests for several real or observed datasets. Not only they are easy to use and do not need any post-modeling inputs, but also, using these heuristics, the analyst can attain useful information about why the NB-L is preferred over the NB - or vice versa- when modeling data. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Reducing the negative human-health impacts of bioenergy crop emissions through region-specific crop selection

    International Nuclear Information System (INIS)

    Porter, William C; Rosenstiel, Todd N; Barsanti, Kelley; Guenther, Alex; Lamarque, Jean-Francois

    2015-01-01

    An expected global increase in bioenergy-crop cultivation as an alternative to fossil fuels will have consequences on both global climate and local air quality through changes in biogenic emissions of volatile organic compounds (VOCs). While greenhouse gas emissions may be reduced through the substitution of next-generation bioenergy crops such as eucalyptus, giant reed, and switchgrass for fossil fuels, the choice of species has important ramifications for human health, potentially reducing the benefits of conversion due to increases in ozone (O 3 ) and fine particulate matter (PM 2.5 ) levels as a result of large changes in biogenic emissions. Using the Community Earth System Model we simulate the conversion of marginal and underutilized croplands worldwide to bioenergy crops under varying future anthropogenic emissions scenarios. A conservative global replacement using high VOC-emitting crop profiles leads to modeled population-weighted O 3 increases of 5–27 ppb in India, 1–9 ppb in China, and 1–6 ppb in the United States, with peak PM 2.5 increases of up to 2 μg m −3 . We present a metric for the regional evaluation of candidate bioenergy crops, as well as results for the application of this metric to four representative emissions profiles using four replacement scales (10–100% maximum estimated available land). Finally, we assess the total health and climate impacts of biogenic emissions, finding that the negative consequences of using high-emitting crops could exceed 50% of the positive benefits of reduced fossil fuel emissions in value. (letter)

  6. Study of neutron-deficient Sn isotopes

    International Nuclear Information System (INIS)

    Auger, G.

    1982-05-01

    The formation of neutron deficient nuclei by heavy ion reactions is investigated. The experimental technique is presented, and the results obtained concerning Sn et In isotopes reported: first excited states of 106 Sn, high spin states in 107 Sn and 107 In; Yrast levels of 106 Sn, 107 Sn, 108 Sn; study of neutron deficient Sn and In isotopes formed by the desintegration of the compound nucleus 112 Xe. All these results are discussed [fr

  7. Selective attention and mismatch negativity in antipsychotic-naïve, first-episode schizophrenia patients before and after 6 months of antipsychotic monotherapy

    DEFF Research Database (Denmark)

    Oranje, B.; Aggernaes, B.; Rasmussen, H.

    2017-01-01

    -naïve patients with schizophrenia and an equal number of healthy controls were tested in a selective attention and a typical mismatch negativity (MMN) paradigm at baseline and after 6 months. The patients were treated with quetiapine according to their clinical needs during the period between baseline and follow......-up, whereas controls received no treatment. Results Patients showed lower MMN and P200 amplitude than healthy controls in the selective attention paradigm at baseline, while this was not the case for MMN of the typical MMN paradigm. Interestingly, after 6 months treatment, this MMN deficit was only......Background Attention deficits have been frequently reported in schizophrenia. It has been suggested that treatment with second-generation antipsychotics can ameliorate these deficits. In this study, the influence of 6 months treatment with quetiapine, a compound with less affinity for dopamine D2...

  8. Lithium alloy negative electrodes

    Science.gov (United States)

    Huggins, Robert A.

    The 1996 announcement by Fuji Photo Film of the development of lithium batteries containing convertible metal oxides has caused a great deal of renewed interest in lithium alloys as alternative materials for use in the negative electrode of rechargeable lithium cells. The earlier work on lithium alloys, both at elevated and ambient temperatures is briefly reviewed. Basic principles relating thermodynamics, phase diagrams and electrochemical properties under near-equilibrium conditions are discussed, with the Li-Sn system as an example. Second-phase nucleation, and its hindrance under dynamic conditions plays an important role in determining deviations from equilibrium behavior. Two general types of composite microstructure electrodes, those with a mixed-conducting matrix, and those with a solid electrolyte matrix, are discussed. The Li-Sn-Si system at elevated temperatures, and the Li-Sn-Cd at ambient temperatures are shown to be examples of mixed-conducting matrix microstructures. The convertible oxides are an example of the solid electrolyte matrix type. Although the reversible capacity can be very large in this case, the first cycle irreversible capacity required to convert the oxides to alloys may be a significant handicap.

  9. SN 1987A. Theory

    International Nuclear Information System (INIS)

    Schaeffer, R.

    1987-03-01

    SN 1987A was unique in many aspects. The most striking, undoubtedly, is its low luminosity, nearly two orders of magnitude below the expectations based on supernovae currently observed in external galaxies. The rise time of the optical emission, usually a few days, was for SN 1987A, of the order of a few hours. Also its surface temperature is surprisingly low, 5000K. The neutrino burst has been detected. It was observed twice, with a time difference of 5 hours, the second burst occurring within 3 hours of the onset of the optical signal. In this talk, I will discuss how these strange events fit with the theoretical models of supernova explosions, how they differ in some cases, and try to evaluate the degree of certainty -or uncertainty- of our present knowledge on how these extremely powerful star explosions occur

  10. Improving the selectivity and sensitivity for quantifying 8-α-hydroxy-mutilin in rabbit tissues by using basic mobile phases and negative ionization.

    Science.gov (United States)

    Tan, Aimin; Gu, Guifen; Gui, Xuan; Wu, Yanxin; Bolger, Gordon; Licollari, Albert; Fanaras, John C

    2018-01-01

    Previously reported LC-MS methods for quantifying 8-α-hydroxy-mutilin (a marker residue of tiamulin) in tissues all used a pseudo MRM transition (from protonated molecular ion to protonated molecular ion, m/z 337→337) due to difficulties in finding a product ion, leading to suboptimal selectivity and sensitivity for detection. By using electrospray negative ionization in a basic medium, we, for the first time, found a highly selective and sensitive true MRM transition for 8-α-hydroxy-mutilin, m/z 335→179. With this newly found MRM transition and the use of pleuromutilin as the internal standard, a very sensitive, selective, and robust LC-MS/MS method has been developed and validated for quantifying 8-α-hydroxy-mutilin in rabbit tissues (muscle, liver, kidney, and fat). In comparison with the previously published methods, the selectivity and sensitivity were significantly improved. For the concentration range validated (0.2-10ppm or 0.2-10μg/g), the within-run and between-run accuracies (% bias) ranged from -5.0 to 3.1 and -4.9 to 3.0, respectively. The% CV ranged from 2.2 to 6.6 and 4.7 to 8.3 for within-run and between-run precisions, respectively. The validated method was successfully used to support two GLP tissue residue depletion studies in rabbits. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Co-receptor choice by V alpha14i NKT cells is driven by Th-POK expression rather than avoidance of CD8-mediated negative selection.

    Science.gov (United States)

    Engel, Isaac; Hammond, Kirsten; Sullivan, Barbara A; He, Xi; Taniuchi, Ichiro; Kappes, Dietmar; Kronenberg, Mitchell

    2010-05-10

    Mouse natural killer T (NKT) cells with an invariant V alpha14-J alpha18 rearrangement (V alpha14 invariant [V alpha14i] NKT cells) are either CD4(+)CD8(-) or CD4(-)CD8(-). Because transgenic mice with forced CD8 expression in all T cells exhibited a profound NKT cell deficit, the absence of CD8 has been attributed to negative selection. We now present evidence that CD8 does not serve as a coreceptor for CD1d recognition and that the defect in development in CD8 transgene homozygous mice is the result of a reduction in secondary T cell receptor alpha rearrangements. Thymocytes from mice hemizygous for the CD8 transgene have a less severe rearrangement defect and have functional CD8(+) V alpha14i NKT cells. Furthermore, we demonstrate that the transcription factor Th, Poxviruses and Zinc finger, and Krüppel family (Th-POK) is expressed by V alpha14i NKT cells throughout their differentiation and is necessary both to silence CD8 expression and for the functional maturity of V alpha14i NKT cells. We therefore suggest that Th-POK expression is required for the normal development of V alpha14i NKT cells and that the absence of CD8 expression by these cells is a by-product of such expression, as opposed to the result of negative selection of CD8-expressing V alpha14i NKT cells.

  12. SN 2006oz

    DEFF Research Database (Denmark)

    Leloudas, Georgios; Chatzopoulos, E.; Dilday, B.

    2012-01-01

    to contribute to a better understanding of these objects by studying SN 2006oz, a newly-recognized member of this class. Methods. We present multi-color light curves of SN 2006oz from the SDSS-II SN Survey that cover its rise time, as well as an optical spectrum that shows that the explosion occurred at z ~ 0.......376. We fitted black-body functions to estimate the temperature and radius evolution of the photosphere and used the parametrized code SYNOW to model the spectrum. We constructed a bolometric light curve and compared it with explosion models. In addition, we conducted a deep search for the host galaxy...... to a recombination wave in a circumstellar medium (CSM) and discuss whether this is a common property of all similar explosions. The subsequent rise can be equally well described by input from a magnetar or by ejecta-CSM interaction, but the models are not well constrained owing to the lack of post...

  13. Discovery of N-(Naphtho[1,2-b]Furan-5-Yl Benzenesulfonamides as Novel Selective Inhibitors of Triple-Negative Breast Cancer (TNBC

    Directory of Open Access Journals (Sweden)

    Ya Chen

    2018-03-01

    Full Text Available Any type of breast cancer not expressing genes of the estrogen receptor (ER, progesterone receptor (PR, or human epidermal growth factor receptor 2 (HER2 is referred to as triple-negative breast cancer (TNBC. Accordingly, TNBCs do not respond to hormonal therapies or medicines targeting the ER, PR, or HER2. Systemic chemotherapy is therefore the only treatment option available today and prognoses remain poor. We report the discovery and characterization of N-(naphtho[1,2-b]furan-5-ylbenzenesulfonamides as selective inhibitors of TNBCs. These inhibitors were identified by virtual screening and inhibited different TNBC cell lines with IC50 values of 2–3 μM. The compounds did not inhibit normal (i.e. MCF-7 and MCF-10A cells in vitro, indicating their selectivity against TNBC cells. Considering the selectivity of these inhibitors for TNBC, these compounds and analogs can serve as a promising starting point for further research on effective TNBC inhibitors.

  14. Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

    Directory of Open Access Journals (Sweden)

    Liu Mei Lee

    2013-01-01

    Full Text Available This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also discussed. Sn-Ag-Cu lead-free solder alloys are the most promising candidate for the replacement of Sn-Pb solders in modern microelectronic technology. Sn-Ag-Cu solders could possibly be considered and adapted in miniaturization technologies. Therefore, this paper should be of great interest to a large selection of electronics interconnect materials, reliability, processes, and assembly community.

  15. Phase formation in Mg-Sn-Si and Mg-Sn-Si-Ca alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kozlov, A.; Groebner, J. [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany); Schmid-Fetzer, R., E-mail: schmid-fetzer@tu-clausthal.de [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany)

    2011-02-17

    Research highlights: > The solidification paths of ternary and quaternary alloys are analyzed in detail, using the tool of thermodynamic calculations. > The precipitation sequence of phases and their amounts compare well with the microstructure of alloys. > The most efficient comparison to the experimental thermal analysis data is done by calculation of the enthalpy variation with temperature. > The viability of a procedure for the selection of multicomponent key samples is demonstrated for the development of the Mg-Ca-Si-Sn phase diagram. - Abstract: Experimental work is done and combined with the Calphad method to generate a consistent thermodynamic description of the Mg-Ca-Si-Sn quaternary system, validated for Mg-rich alloys. The viability of a procedure for the selection of multicomponent key samples is demonstrated for this multicomponent system. Dedicated thermal analysis with DTA/DSC on sealed samples is performed and the microstructure of slowly solidified alloys is analyzed using SEM/EDX. The thermodynamic description and phase diagram of the ternary Mg-Si-Sn system, developed in detail also in this work, deviates significantly from a previous literature proposal. The phase formation in ternary and quaternary alloys is analyzed using the tool of thermodynamic equilibrium and Scheil calculations for the solidification paths and compared with present experimental data. The significant ternary/quaternary solid solubilities of pertinent intermetallic phases are quantitatively introduced in the quaternary Mg-Ca-Si-Sn phase diagram and validated by experimental data.

  16. Correlation between the resistivity and the atomic clusters in liquid Cu-Sn alloys

    Science.gov (United States)

    Jia, Peng; Zhang, Jinyang; Hu, Xun; Li, Cancan; Zhao, Degang; Teng, XinYing; Yang, Cheng

    2018-05-01

    The liquid structure of CuxSn100-x (x = 0, 10, 20, 33, 40, 50, 60, 75, 80 and 100) alloys with atom percentage were investigated with resistivity and viscosity methods. It can be found from the resistivity data that the liquid Cu75Sn25 and Cu80Sn20 alloys had a negative temperature coefficient of resistivity (TCR), and liquid Cu75Sn25 alloy had a minimum value of -9.24 μΩ cm K-1. While the rest of liquid Cu-Sn alloys had a positive TCR. The results indicated that the Cu75Sn25 atomic clusters existed in Cu-Sn alloys. In addition, the method of calculating the percentage of Cu75Sn25 atomic clusters was established on the basis of resistivity theory and the law of conservation of mass. The Cu75Sn25 alloy had a maximum volume of the atomic clusters and a highest activation energy. The results further proved the existence of Cu75Sn25 atomic clusters. Furthermore, the correlation between the liquid structure and the resistivity was established. These results provide a useful reference for the investigation of liquid structure via the sensitive physical properties to the liquid structure.

  17. The interleukin-15 system suppresses T cell-mediated autoimmunity by regulating negative selection and nT(H)17 cell homeostasis in the thymus.

    Science.gov (United States)

    Hou, Mau-Sheng; Huang, Shih-Ting; Tsai, Ming-Han; Yen, Ching-Cheng; Lai, Yein-Gei; Liou, Yae-Huei; Lin, Chih-Kung; Liao, Nan-Shih

    2015-01-01

    The interleukin-15 (IL-15) system is important for regulating both innate and adaptive immune responses, however, its role in autoimmune disease remained unclear. Here we found that Il15(-/-) and Il15ra(-/-) mice spontaneously developed late-onset autoimmune phenotypes. CD4(+) T cells of the knockout mice showed elevated autoreactivity as demonstrated by the induction of lymphocyte infiltration in the lacrimal and salivary glands when transferred into nude mice. The antigen-presenting cells in the thymic medullary regions expressed IL-15 and IL-15Rα, whose deficiency resulted in insufficient negative selection and elevated number of natural IL-17A-producing CD4(+) thymocytes. These findings reveal previously unknown functions of the IL-15 system in thymocyte development, and thus a new layer of regulation in T cell-mediated autoimmunity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. 51Cr diffusion in Zr-Sn alloys

    International Nuclear Information System (INIS)

    Nicolai, L.I.; Migoni, R.L.; Hojvat de Tendler, Ruth

    1982-01-01

    The 51 Cr volume diffusion in Zr-Sn alloys is measured in polycrystals with big grains by the thin-film method. The Sn content in the alloys ranges from 0.39% at to 6.66 % at. In the beta-phase the analysed temperature range is 982 deg C-1240 deg C. The Sn dehances the 51 Cr diffusion in beta-Zr, the effect being small but well defined. Assuming the formation of Sn-Cr dimers, the linear dehancement coefficient b and the parameters for the variation of b with temperature were calculated. The parameters Q and D o were calculated for the more diluted alloys and, upon application of the Zener theory for D o , a negative contribution to the activation entropy is found. Three experiments at different temperatures were performed in the alpha-phase. 51 Cr diffuses very fast in alpha-Zr-Sn. No definite correlation is found between the 51 Cr diffusivity and the increasing Sn concentration, probably due to the anisotropy of the alfa-phase. (M.E.L.) [es

  19. LARP Long Nb3Sn Quadrupole Design

    International Nuclear Information System (INIS)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Ferracin, P.; Ghosh, A.; Hafalia, R.; Hannaford, R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

    2008-01-01

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb 3 Sn conductor. The goal of these magnets is to be a proof of principle that Nb 3 Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure

  20. LARP Long Nb3Sn Quadrupole Design

    International Nuclear Information System (INIS)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Felice, H.; Ferracin, P.; Fermilab; Brookhaven; LBL, Berkeley; Texas A-M

    2007-01-01

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb3Sn conductor. The goal of these magnets is to be a proof of principle that Nb3Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure

  1. LARP Long Nb3Sn Quadrupole Design

    International Nuclear Information System (INIS)

    Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidize, G.; Dietderich, D.; Feher, S.; Felice, H.; Ferracin, P.; Ghosh, A.; Hafalia, A.R.; Hannaford, C.R.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Lietzke, A.; McInturff, A.; Muratore, J.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmalzle, J.; Tartaglia, M.; Turrioni, D.; Wanderer, P.; Whitson, G.; Zlobin, A.V.

    2007-01-01

    A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb 3 Sn conductor. The goal of these magnets is to be a proof of principle that Nb 3 Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure

  2. Selective attention and mismatch negativity in antipsychotic-naïve, first-episode schizophrenia patients before and after 6 months of antipsychotic monotherapy.

    Science.gov (United States)

    Oranje, B; Aggernaes, B; Rasmussen, H; Ebdrup, B H; Glenthøj, B Y

    2017-09-01

    Attention deficits have been frequently reported in schizophrenia. It has been suggested that treatment with second-generation antipsychotics can ameliorate these deficits. In this study, the influence of 6 months treatment with quetiapine, a compound with less affinity for dopamine D2 receptors than for serotonergic 5-HT2A receptors, on electrophysiological parameters of attention was investigated in a group of antipsychotic-naïve, first-episode schizophrenia patients compared with a group of age- and gender-matched healthy controls. A total of 34 first-episode, antipsychotic-naïve patients with schizophrenia and an equal number of healthy controls were tested in a selective attention and a typical mismatch negativity (MMN) paradigm at baseline and after 6 months. The patients were treated with quetiapine according to their clinical needs during the period between baseline and follow-up, whereas controls received no treatment. Patients showed lower MMN and P200 amplitude than healthy controls in the selective attention paradigm at baseline, while this was not the case for MMN of the typical MMN paradigm. Interestingly, after 6 months treatment, this MMN deficit was only ameliorated in patients treated with above median dosages of quetiapine. Patients had lower P3B amplitude, yet showed similar levels of processing negativity and N100 amplitude compared with healthy controls, both at baseline and follow-up. The results indicate that deficits in MMN, P200 and P3B amplitude are present at early stages of schizophrenia, although depending on the paradigm used. Furthermore, the results indicate that 6 months quetiapine treatment ameliorates MMN but not P3B deficits, and only in those subjects on higher dosages.

  3. Isomer shifts and chemical bonding in crystalline Sn(II) and Sn(IV) compounds

    International Nuclear Information System (INIS)

    Terra, J.; Guenzburger, D.

    1991-01-01

    First-principles self-consistent Local Density calculations of the electronic structure of clusters representing Sn(II) (SnO, SnF 2 , SnS, SnSe) and Sn(IV) (SnO 2 , SnF 4 ) crystalline compounds were performed. Values of the electron density at the Sn nucleus were obtained and related to measured values of the Moessbauer Isomer Shifts reported in the literature. The nuclear parameter of 119 Sn derived was ΔR/R=(1.58±0.14)x10 -4 . The chemical bonding in the solids was analysed and related to the electron densities obtained. (author)

  4. Interface between Sn-Sb-Cu solder and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sebo, P., E-mail: Pavel.Sebo@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Svec, P. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janickovic, D.; Illekova, E. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine)

    2011-07-15

    Highlights: {yields} New lead-free solder materials based on Sn-Sb-Cu were designed and prepared. {yields} Melting and solidification temperatures of the solders have been determined. {yields} Cu-substrate/solder interaction has been analyzed and quantified. {yields} Phases formed at the solder-substrate interface have been identified. {yields} Composition and soldering atmospheres were correlated with joint strength. - Abstract: Influence of antimony and copper in Sn-Sb-Cu solder on the melting and solidification temperatures and on the microstructure of the interface between the solder and copper substrate after wetting the substrate at 623 K for 1800 s were studied. Microstructure of the interface between the solder and copper substrates in Cu-solder-Cu joints prepared at the same temperature for 1800 s was observed and shear strength of the joints was measured. Influence of the atmosphere - air with the flux and deoxidising N{sub 2} + 10H{sub 2} gas - was taken into account. Thermal stability and microstructure were studied by differential scanning calorimetry (DSC), light microscopy, scanning electron microscopy (SEM) with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD). Melting and solidification temperatures of the solders were determined. An interfacial transition zone was formed by diffusion reaction between solid copper and liquid solder. At the interface Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} phases arise. Cu{sub 3}Sn is adjacent to the Cu substrate and its thickness decreases with increasing the amount of copper in solder. Scallop Cu{sub 6}Sn{sub 5} phase is formed also inside the solder drop. The solid solution Sn(Sb) and SbSn phase compose the interior of the solder drop. Shear strength of the joints measured by push-off method decreases with increasing Sb concentration. Copper in the solder shows even bigger negative effect on the strength.

  5. Preventive effects of etodolac, a selective cyclooxygenase-2 inhibitor, on cancer development in extensive metaplastic gastritis, a Helicobacter pylori-negative precancerous lesion.

    Science.gov (United States)

    Yanaoka, Kimihiko; Oka, Masashi; Yoshimura, Noriko; Deguchi, Hisanobu; Mukoubayashi, Chizu; Enomoto, Shotaro; Maekita, Takao; Inoue, Izumi; Ueda, Kazuki; Utsunomiya, Hirotoshi; Iguchi, Mikitaka; Tamai, Hideyuki; Fujishiro, Mitsuhiro; Nakamura, Yasushi; Tsukamoto, Tetsuya; Inada, Kenichi; Takeshita, Tatsuya; Ichinose, Masao

    2010-03-15

    The present study investigated the preventive effects of etodolac, a selective cyclo-oxygenase (COX)-2 inhibitor, on metachronous cancer development after endoscopic resection of early gastric cancer. Among 267 early gastric cancer patients who underwent endoscopic resection, 47 patients with extensive metaplastic gastritis were selected based on endoscopic findings and our previously described criteria of serum pepsinogen (PG) test-positive and Helicobacter pylori antibody-negative conditions. Nonrandomized etodolac treatment (300 mg/day) was administered to 26 patients (Group A), while the remaining 21 patients were untreated (Group B). No significant differences in age, sex distribution, lifestyle factors or extent of metaplastic gastritis at baseline were identified between groups. Patients were followed for metachronous cancer development with endoscopy every 6-12 months for up to 5 years. Mean (standard deviation) follow-up period was 4.2 (0.9) years. In Group B, 5 cancers developed (incidence rate = 6,266/100,000 person-years), significantly more than the 1 cancer in Group A (incidence rate = 898/100,000 person-years; p gastritis as revealed by endoscopic findings or by serum PG levels, but effectively reduced metachronous cancer development in patients with extensive metaplastic gastritis. These results strongly suggest that chemoprevention of cancer in the metaplastic stomach is possible by controlling COX-2 expression.

  6. Synthesis and Characterization of Sn2+- based and Bi3+- based metal oxides for photocatalytic applications

    KAUST Repository

    Noureldine, Dalal

    2016-01-01

    containing metals with s2d10 electronic configuration such as Sn2+ or Bi3+ which shifts the valence band position negatively. Efficient water splitting can, however, be only achieved by understanding the fundamental semiconductor properties of underlying

  7. Thioglycolic acid (TGA) assisted hydrothermal synthesis of SnS nanorods and nanosheets

    International Nuclear Information System (INIS)

    Biswas, Subhajit; Kar, Soumitra; Chaudhuri, Subhadra

    2007-01-01

    Nanorods and nanosheets of tin sulfide (SnS) were synthesized by a novel thioglycolic acid (TGA) assisted hydrothermal process. The as prepared nanostructures were characterized by X-ray diffraction (XRD) study, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD study reveals the formation of well-crystallized orthorhombic structure of SnS. Diameter of the SnS nanorods varied within 30-100 nm. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) patterns identify the single crystalline nature for the SnS nanocrystals. The mechanism for the TGA assisted growth for the nanosheets and nanorods have been discussed

  8. Enthalpy of mixing of liquid Co–Sn alloys

    International Nuclear Information System (INIS)

    Yakymovych, A.; Fürtauer, S.; Elmahfoudi, A.; Ipser, H.; Flandorfer, H.

    2014-01-01

    Highlights: • The enthalpies of mixing of liquid Co–Sn alloys between T = (673 and 1773) K. • The temperature dependence of the enthalpies of mixing was described. • Full report of measured values including polynomial coefficients. - Abstract: A literature overview of enthalpy of mixing data for liquid Co–Sn alloys shows large scattering but no clear temperature dependence. Therefore drop calorimetry was performed in the Co–Sn system at twelve different temperatures in 100 K steps in the temperature range (673 to 1773) K. The integral enthalpy of mixing was determined starting from 1173 K and fitted to a standard Redlich–Kister polynomial. In addition, the limiting partial molar enthalpy of Co in Sn was investigated by small additions of Co to liquid Sn at temperatures (673 to 1773) K. The integral and partial molar enthalpies of the Co–Sn system generally show an exothermic mixing behavior. Significant temperature dependence was detected for the enthalpies of mixing. The minimum integral enthalpy values vary with rising temperature from approx. −7820 J/mol at T = 1173 K to −1350 J/mol at T = 1773 K; the position of the minimum is between (59 and 61) at.% Co. The results are discussed and compared with literature data available for this system. X-ray studies and scanning electron microscopy of selected alloys obtained from the calorimetric measurements were carried out in order to check the completeness of the solution process

  9. In-beam γ-ray spectroscopy in the vicinity of 100Sn

    International Nuclear Information System (INIS)

    Seweryniak, D.

    1998-01-01

    In recent years, in-beam x-ray experiments supplied a vast amount of data on high-spin states in nuclei in the vicinity of 100 Sn. The present contribution reviews spectroscopic information obtained recently for N ≥ 50 nuclei around 100 Sn, with emphasis on isomer studies, and discusses selected results in the frame of the shell model

  10. Negative effects of climate warming on maize yield are reversed by the changing of sowing date and cultivar selection in Northeast China.

    Science.gov (United States)

    Liu, Zhijuan; Hubbard, Kenneth G; Lin, Xiaomao; Yang, Xiaoguang

    2013-11-01

    Northeast China (NEC) accounts for about 30% of the nation's maize production in China. In the past three decades, maize yields in NEC have increased under changes in climate, cultivar selection and crop management. It is important to investigate the contribution of these changing factors to the historical yield increases to improve our understanding of how we can ensure increased yields in the future. In this study, we use phenology observations at six sites from 1981 to 2007 to detect trends in sowing dates and length of maize growing period, and then combine these observations with in situ temperature data to determine the trends of thermal time in the maize growing period, as a measure of changes in maize cultivars. The area in the vicinity of these six sites accounts for 30% of NEC's total maize production. The agricultural production systems simulator, APSIM-Maize model, was used to separate the impacts of changes in climate, sowing dates and thermal time requirements on maize phenology and yields. In NEC, sowing dates trended earlier in four of six sites and maturity dates trended later by 4-21 days. Therefore, the period from sowing to maturity ranged from 2 to 38 days longer in 2007 than it was in 1981. Our results indicate that climate trends alone would have led to a negative impact on maize. However, results from the adaptation assessments indicate that earlier sowing dates increased yields by up to 4%, and adoption of longer season cultivars caused a substantial increase in yield ranging from 13% to 38% over the past 27 years. Therefore, earlier sowing dates and introduction of cultivars with higher thermal time requirements in NEC have overcome the negative effects of climate change and turned what would have otherwise been a loss into a significant increase in maize yield. © 2013 John Wiley & Sons Ltd.

  11. Reduced graphene oxide decorated with Fe doped SnO{sub 2} nanoparticles for humidity sensor

    Energy Technology Data Exchange (ETDEWEB)

    Toloman, D. [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Popa, A., E-mail: popa@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Stan, M.; Socaci, C.; Biris, A.R. [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Katona, G. [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, 400028 Cluj-Napoca (Romania); Tudorache, F. [Interdisciplinary Research Department – Field Science & RAMTECH, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania); Petrila, I. [Interdisciplinary Research Department – Field Science & RAMTECH, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania); Faculty of Automatic Control and Computer Engineering, Gheorghe Asachi Technical University, 27 Dimitrie Mangeron Street, 700050 Iasi (Romania); Iacomi, F. [Faculty of Physics, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania)

    2017-04-30

    Highlights: • Reduced graphene oxide decorated with Fe doped SnO{sub 2} nanoparticles were synthesized. • The decoration of rGO layers with SnO{sub 2}:Fe nanoparticles was highlited by TEM. • The reduction of graphene oxide was evidenced using XRD and FT-IR. • Sensitivity tests for relative humidity (RH) were carried out. • The composite sensor exhibited enhanced sensing response as compared with Fe:SnO{sub 2}. - Abstract: Reduced graphene oxide (rGO) decorated with Fe doped SnO{sub 2} nanoparticles were fabricated via the electrostatic interaction between positively charged modified Fe-doped SnO{sub 2} oxide and negatively charged graphene oxide (GO) in the presence of poly(allylamine) hydrochloride (PAH). The decoration of rGO layers with SnO{sub 2}:Fe nanoparticles was highlited by TEM microsopy. For composite sample the diffraction patterns coincide well with those of SnO{sub 2}:Fe nanoparticles. The reduction of graphene oxide was evidenced using XRD and FT-IR spectroscopy. The formation of SnO{sub 2}:Fe-PAH-graphene composites was confirmed by FT-IR, Raman and EPR spectroscopy. Sensitivity tests for relative humidity (RH) measurements were carried out at five different concentrations of humid air at room temperature. The prepared composite sensor exhibited a higher sensing response as compared with Fe:SnO{sub 2} nanoparticles.

  12. Determinations of enthalpy and partial molar enthalpy in the alloys Bi–Cd–Ga–In–Zn, Bi–Cd–Ga–Zn and Au–Cu–Sn

    International Nuclear Information System (INIS)

    Arslan, Hüseyin

    2015-01-01

    In the present study, the relations of thermodynamic associated with Chou's general solution model (GSM), the models of Muggianu and Toop have been used in order to calculate the mixing enthalpy and partial molar mixing enthalpy of mixing of Bi–Cd–Ga–In–Zn, Bi–Cd–Ga–Zn with equimolar section at a temperature of 730 K and Au–Cu–Sn with the section x Au /x Cu = 1/1 on the entire molar fraction range as a function of alloy composition at a temperature of 900 K. Some negativities are reported in the selected alloys mentioned above, particularly at high temperatures for the human health as well as difficulties in experimental measurement and high costs. Moreover, aim of us is to close the current article gap seen in the literature. In order to close the current gap seen in the literature, the article on the thermodynamic properties of the Bi–Cd–Ga–In–Zn alloys are presented in this study. - Highlights: • Thermodynamic properties of alloys in the study in given conditions were treated. • The activity of Bi seen in all models shows greatly positive deviation from ideality. • The enthalpy of Sn shows small negative values in x Au /x Cu = 1 at 900 K. • The activity of Sn shows negative deviation from ideality in the same conditions

  13. When negation is not negation

    OpenAIRE

    Milicevic, Nataša

    2008-01-01

    In this paper I will discuss the formation of different types of yes/no questions in Serbian (examples in (1)), focusing on the syntactically and semantically puzzling example (1d), which involves the negative auxiliary inversion. Although there is a negative marker on the fronted auxiliary, the construction does not involve sentential negation. This coincides with the fact that the negative quantifying NPIs cannot be licensed. The question formation and sentential negation have similar synta...

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

    Science.gov (United States)

    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

  15. Age-related decline in bottom-up processing and selective attention in the very old.

    Science.gov (United States)

    Zhuravleva, Tatyana Y; Alperin, Brittany R; Haring, Anna E; Rentz, Dorene M; Holcomb, Philip J; Daffner, Kirk R

    2014-06-01

    Previous research demonstrating age-related deficits in selective attention have not included old-old adults, an increasingly important group to study. The current investigation compared event-related potentials in 15 young-old (65-79 years old) and 23 old-old (80-99 years old) subjects during a color-selective attention task. Subjects responded to target letters in a specified color (Attend) while ignoring letters in a different color (Ignore) under both low and high loads. There were no group differences in visual acuity, accuracy, reaction time, or latency of early event-related potential components. The old-old group showed a disruption in bottom-up processing, indexed by a substantially diminished posterior N1 (smaller amplitude). They also demonstrated markedly decreased modulation of bottom-up processing based on selected visual features, indexed by the posterior selection negativity (SN), with similar attenuation under both loads. In contrast, there were no group differences in frontally mediated attentional selection, measured by the anterior selection positivity (SP). There was a robust inverse relationship between the size of the SN and SP (the smaller the SN, the larger the SP), which may represent an anteriorly supported compensatory mechanism. In the absence of a decline in top-down modulation indexed by the SP, the diminished SN may reflect age-related degradation of early bottom-up visual processing in old-old adults.

  16. SacB-SacR gene cassette as the negative selection marker to suppress Agrobacterium overgrowth in Agrobacterium-mediated plant transformation

    Directory of Open Access Journals (Sweden)

    Yiming Liu

    2016-10-01

    Full Text Available Agrobacterium overgrowth is a common problem in Agrobacterium-mediated plant transfor-mation. To suppress the Agrobacterium overgrowth, various antibiotics have been used during plant tissue culture steps. The antibiotics are expensive and may adversely affect plant cell differentiation and reduce plant transformation efficiency. The SacB-SacR proteins are toxic to most Agrobacterium tumefaciens strains when they are grown on culture medium sup¬plemented with sucrose. Therefore, SacB-SacR genes can be used as negative selection markers to suppress the overgrowth of Agrobacterium tumefaciens in the plant tissue culture process. We generated a mutant Agrobacterium tumefaciens strain GV2260 (recA-SacB/R that has the SacB-SacR cassette inserted into the bacterial genome at the recA gene locus. The mutant Agrobacterium strain is sensitive to sucrose but maintains its ability to transform plant cells in both transient and stable transformation assays. We demonstrated that the mutant strain GV2260 (recA-SacB/R can be inhibited by sucrose that reduces the overgrowth of Agrobacterium and therefore improves the plant transformation efficiency. We employed GV2260 (recA-SacB/R to generate stable transgenic N. benthamiana plants expressing a CRISPR-Cas9 for knocking out a WRKY transcrip¬tion factor.

  17. Pressure effects on topological crystalline insulator SnTe and derived superconductor Sn{sub 0.5}In{sub 0.5}Te

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, V. K.; Shruti,; Patnaik, S., E-mail: spatnaik@mail.jnu.ac.in [School of Physical Sciences, Jawaharlal Nehru University New Delhi (India); Jha, Rajveer; Awana, V. P. S. [National Physical Laboratory, New Delhi 110012 (India)

    2016-05-23

    We are reporting decrease in superconducting transition temperature accompanied by increased metallicity in indium doped SnTe superconductor. SnTe is a topological crystalline insulator and superconductivity is achieved by indium substitution in place of tin. With application of hydrostatic pressure we find negative dT{sub c}/dP of ~ -0.6K/GPa upto 2.5 GPa. The overall phenomenon is ascribed to unconventional superconductivity. Decrease in resistivity is also seen in single crystal SnTe with application of pressure but no evidence of superconductivity is observed.

  18. Negative hyper-selection of metastatic colorectal cancer patients for anti-EGFR monoclonal antibodies: the PRESSING case-control study.

    Science.gov (United States)

    Cremolini, C; Morano, F; Moretto, R; Berenato, R; Tamborini, E; Perrone, F; Rossini, D; Gloghini, A; Busico, A; Zucchelli, G; Baratelli, C; Tamburini, E; Tampellini, M; Sensi, E; Fucà, G; Volpi, C; Milione, M; Di Maio, M; Fontanini, G; De Braud, F; Falcone, A; Pietrantonio, F

    2017-12-01

    Refining the selection of metastatic colorectal cancer patients candidates for anti-epidermal growth factor receptor (EGFR) monoclonal antibodies beyond RAS and BRAF testing is a challenge of precision oncology. Several uncommon genomic mechanisms of primary resistance, leading to activation of tyrosine kinase receptors other than EGFR or downstream signalling pathways, have been suggested by preclinical and retrospective studies. We conducted this multicentre, prospective, case-control study to demonstrate the negative predictive impact of a panel of rare genomic alterations [PRESSING (PRimary rESiStance IN RAS and BRAF wild-type metastatic colorectal cancer patients treated with anti-eGfr monoclonal antibodies) panel], including HER2/MET amplifications, ALK/ROS1/NTRK1-3/RET fusions and PIK3CA mutations. Hypothesizing a prevalence of candidate alterations of 15% and 0% in resistant and sensitive RAS and BRAF wild-type patients, respectively, with two-sided α and β errors of 0.05 and 0.20, 47 patients per group were needed. Forty-seven patients per group were included. PRESSING panel alterations were significantly more frequent in resistant (24 out of 47, 51.1%) than in sensitive (1 out of 47, 2.1%) patients (P < 0.001) and in right- (12 out of 29, 41.4%) than left-sided (13 out of 65, 20.0%) tumours (P = 0.03). The predictive accuracy of PRESSING panel and sidedness was 75.3% and 70.2%, respectively. Among hyper-selected patients, right-sidedness was still associated with resistance (P = 0.002). The predictive accuracy of the combined evaluation of PRESSING panel and sidedness was 80.4%. As a secondary analysis, 8 (17.0%) resistant and 0 sensitive patients showed microsatellite instability (P < 0.001). The investigated panel of genomic alterations allows refining the selection of RAS and BRAF wild-type metastatic colorectal cancer patients candidates for anti-EGFRs, partially explaining and further corroborating the predictive ability of primary

  19. Epstein-Barr virus (EBV) recombinants: use of positive selection markers to rescue mutants in EBV-negative B-lymphoma cells.

    Science.gov (United States)

    Wang, F; Marchini, A; Kieff, E

    1991-04-01

    The objective of these experiments was to develop strategies for creation and identification of recombinant mutant Epstein-Barr viruses (EBV). EBV recombinant molecular genetics has been limited to mutations within a short DNA segment deleted from a nontransforming EBV and an underlying strategy which relies on growth transformation of primary B lymphocytes for identification of recombinants. Thus, mutations outside the deletion or mutations which affect transformation cannot be easily recovered. In these experiments we investigated whether a toxic drug resistance gene, guanine phosphoribosyltransferase or hygromycin phosphotransferase, driven by the simian virus 40 promoter can be recombined into the EBV genome and can function to identify B-lymphoma cells infected with recombinant virus. Two different strategies were used to recombine the drug resistance marker into the EBV genome. Both utilized transfection of partially permissive, EBV-infected B95-8 cells and positive selection for cells which had incorporated a functional drug resistance gene. In the first series of experiments, B95-8 clones were screened for transfected DNA that had recombined into the EBV genome. In the second series of experiments, the transfected drug resistance marker was linked to the plasmid and lytic EBV origins so that it was maintained as an episome and could recombine with the B95-8 EBV genome during virus replication. The recombinant EBV from either experiment could be recovered by infection and toxic drug selection of EBV-negative B-lymphoma cells. The EBV genome in these B-lymphoma cells is frequently an episome. Virus genes associated with latent infection of primary B lymphocytes are expressed. Expression of Epstein-Barr virus nuclear antigen 2 (EBNA-2) and the EBNA-3 genes is variable relative to that of EBNA-1, as is characteristic of some naturally infected Burkitt tumor cells. Moreover, the EBV-infected B-lymphoma cells are often partially permissive for early replicative

  20. Cluster-derived Ir-Sn/SiO2 catalysts for the catalytic dehydrogenation of propane: A spectroscopic study

    KAUST Repository

    Gallo, Alessandro

    2013-01-01

    Ir-Sn bimetallic silica-based materials have been prepared via deposition of the molecular organometallic clusters (NEt4)2[Ir 4(CO)10(SnCl3)2] and NEt 4[Ir6(CO)15(SnCl3)] or via deposition of Sn organometallic precursor Sn(n-C4H9) 4 onto pre-formed Ir metal particles. These solids possess promising properties, in terms of selectivity, as catalysts for propane dehydrogenation to propene. Detailed CO-adsorption DRIFTS, XANES and EXAFS characterization studies have been performed on these systems in order to compare the structural and electronic evolution of systems in relation to the nature of the Ir-Sn bonds present in the precursor compounds and to propose a structural model of the Ir-Sn species present at the silica surface of the final catalyst. © 2013 The Royal Society of Chemistry.

  1. An Influence Study of Hydrogen Evolution Characteristics on the Negative Strap Corrosion of Lead Acid Battery

    Directory of Open Access Journals (Sweden)

    Zhong Guobin

    2015-01-01

    Full Text Available Negative strap corrosion is an important reason for the failure of valve regulated lead acid battery. This paper selected the Pb-Sb alloy material and Pb-Sn alloy material, made an investigation on the negative corrosion resistance and hydrogen evolution of these two alloy materials by scanning electron microscope analysis, metallographic analysis, chemical study and linear sweep voltammetry, and discussed the influence of lead alloy hydrogen evolution on the negative strap corrosion. The results showed that the hydrogen evolution reaction rates of the alloys had an impact on the corrosion areas with the maximum thickness of the alloys and the depth of corrosion layers. Greater hydrogen evolution reaction rate can lead to shorter distance between the corrosion area with the maximum thickness and the liquid level; whereas the greater corrosion layer thickness can bring aggravated risk of negative strap corrosion failure.

  2. Low-temperature processed SnO{sub 2} compact layer for efficient mesostructure perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Jinxia; Xiong, Qiu; Feng, Bingjie; Xu, Yang; Zhang, Jun; Wang, Hao, E-mail: nanoguy@126.com

    2017-01-01

    Highlights: • Low-temperature processed 70 nm cl-SnO{sub 2} device exhibits maximum PCE. • Champion PSC after SnCl{sub 4} treatment acquires PCE of 15.07%. • Cl-SnO{sub 2} PSC via SnCl{sub 4} treatment exhibits superior stability to cl-TiO{sub 2} based PSC. - Abstract: SnO{sub 2} nanoparticle film has been synthesized via low- temperature (∼180 °C) solution-processing and proposed as compact layer in mesostructure perovskite-type solar cell (PSC). Low-temperature processed SnO{sub 2} compact layer (cl-SnO{sub 2}) brings perfect crystal-lattice and band-gap matching between electron selective layer and FTO substrate and close interface-contact between cl-SnO{sub 2} and mesoporous TiO{sub 2} layer (mp-TiO{sub 2}), which contributes to suppressing carrier recombination and optimizing device performance. In varied thickness cells, 70 nm cl-SnO{sub 2} device exhibits maximum power conversion efficiency (PCE). In order to further restrain photoelectron recombination and improve the photovoltaic performance, the surface modification of cl-SnO{sub 2} by SnCl{sub 4} aqueous solution has been carried out. The recombination behavior in the cell interior is greatly retarded via SnCl{sub 4} treatment and champion PSC after SnCl{sub 4} treatment has acquire PCE of 15.07%, which is higher than PCE of cl-TiO{sub 2} based PSC fabricated with same mp-TiO{sub 2} and perovskite procedures (13.3%). The stability of cl-SnO{sub 2} PSC via SnCl{sub 4} treatment has also been measured and its PCE reduces to 13.0% after 2 weeks in air.

  3. Preparation of highly dispersed Ru-Sn bimetallic supported catalysts from the single source precursors Cp(PPh32Ru-SnX3 (X = Cl or Br

    Directory of Open Access Journals (Sweden)

    Ana Cláudia Bernardes Silva

    2003-06-01

    Full Text Available In this work highly dispersed Ru-Sn bimetallic catalysts have been prepared from organobimetallic Cp(PPh32Ru-SnX3 (X = Cl or Br complexes. These single source precursors can be easily impregnated in high surface area supports, such as activated carbon and sol-gel SiO2, and upon controlled thermal treatment the ligands are released as volatile products resulting in the formation of the bimetallic system Ru-Sn. Catalytic reactions, such as hydrodechlorination of CCl4 and chlorobenzene and TPR (Temperature Programmed Reduction experiments carried out with these RuSn catalysts suggested a strong interaction between Ruthenium and Tin. Mössbauer measurements showed that these materials when exposed to air are immediately oxidized to form Sn (IV. It was shown that upon controlled reduction conditions with H2 it is possible to reduce selectively Sn to different oxidation states and different phases. The Sn oxidation state showed significant effect on the catalytic hydrogenation of 1,5-cyclooctadiene. The use of these single source precursors with a controlled decomposition/reduction procedure allows the preparation of unique catalysts with an intimate interaction between the components ruthenium and tin and the possibility of varying the Sn oxidation state around the Ru metal.

  4. Sentinel Lymph Node Dissection to Select Clinically Node-negative Prostate Cancer Patients for Pelvic Radiation Therapy: Effect on Biochemical Recurrence and Systemic Progression

    Energy Technology Data Exchange (ETDEWEB)

    Grivas, Nikolaos, E-mail: n.grivas@nki.nl [Department of Urology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Wit, Esther [Department of Urology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Pos, Floris [Department of Radiation Oncology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Jong, Jeroen de [Department of Pathology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Vegt, Erik [Department of Nuclear Medicine, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Bex, Axel; Hendricksen, Kees; Horenblas, Simon [Department of Urology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); KleinJan, Gijs [Department of Urology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden (Netherlands); Rhijn, Bas van; Poel, Henk van der [Department of Urology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

    2017-02-01

    Purpose: To assess the efficacy of robotic-assisted laparoscopic sentinel lymph node (SLN) dissection (SLND) to select those patients with prostate cancer (PCa) who would benefit from additional pelvic external beam radiation therapy and long-term androgen deprivation therapy (ADT). Methods and Materials: Radioisotope-guided SLND was performed in 224 clinically node-negative patients scheduled to undergo external beam radiation therapy. Patients with histologically positive SLNs (pN1) were also offered radiation therapy to the pelvic lymph nodes, combined with 3 years of ADT. Biochemical recurrence (BCR), overall survival, and metastasis-free (including pelvic and nonregional lymph nodes) survival (MFS) rates were retrospectively calculated. The Briganti and Kattan nomogram predictions were compared with the observed pN status and BCR. Results: The median prostate-specific antigen (PSA) value was 15.4 ng/mL (interquartile range [IQR] 8-29). A total number of 834 SLNs (median 3 per patient; IQR 2-5) were removed. Nodal metastases were diagnosed in 42% of the patients, with 150 SLNs affected (median 1; IQR 1-2). The 5-year BCR-free and MFS rates for pN0 patients were 67.9% and 87.8%, respectively. The corresponding values for pN1 patients were 43% and 66.6%. The PSA level and number of removed SLNs were independent predictors of BCR and MFS, and pN status was an additional independent predictor of BCR. The 5-year overall survival rate was 97.6% and correlated only with pN status. The predictive accuracy of the Briganti nomogram was 0.665. Patients in the higher quartiles of Kattan nomogram prediction of BCR had better than expected outcomes. The complication rate from SLND was 8.9%. Conclusions: For radioisotope-guided SLND, the high staging accuracy is accompanied by low morbidity. The better than expected outcomes observed in the lower quartiles of BCR prediction suggest a role for SLN biopsy as a potential selection tool for the addition of pelvic radiation

  5. Hierarchical ZnO Nanowires-loaded Sb-doped SnO2-ZnO Micrograting Pattern via Direct Imprinting-assisted Hydrothermal Growth and Its Selective Detection of Acetone Molecules

    OpenAIRE

    Choi, Hak-Jong; Choi, Seon-Jin; Choo, Soyoung; Kim, Il-Doo; Lee, Heon

    2016-01-01

    We propose a novel synthetic route by combining imprinting transfer of a Sb-doped SnO2 (ATO)-ZnO composite micrograting pattern (MP), i.e., microstrip lines, on a sensor substrate and subsequent hydrothermal growth of ZnO nanowires (NWs) for producing a hierarchical ZnO NW-loaded ATO-ZnO MP as an improved chemo-resistive sensing layer. Here, ATO-ZnO MP structure with 3-?m line width, 9-?m pitch, and 6-?m height was fabricated by direct transfer of mixed ATO and ZnO nanoparticle (NP)-dispersed...

  6. Growth of intermetallics between Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layered structures

    International Nuclear Information System (INIS)

    Horváth, Barbara; Illés, Balázs; Shinohara, Tadashi

    2014-01-01

    Intermetallic growth mechanisms and rates are investigated in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. An 8–10 μm thick Sn surface finish layer was electroplated onto a Cu substrate with a 1.5–2 μm thick Ni or Ag barrier layer. In order to induce intermetallic layer growth, the samples were aged in elevated temperatures: 50 °C and 125 °C. Intermetallic layer growth was checked by focused ion beam–scanning ion microscope. The microstructures and chemical compositions of the intermetallic layers were observed with a transmission electron microscope. It has been found that Ni barrier layers can effectively block the development of Cu 6 Sn 5 intermetallics. The intermetallic growth characteristics in the Sn/Cu and Sn/Ni/Cu systems are very similar. The intermetallic layer grows towards the Sn layer and forms a discrete layer. Differences were observed only in the growth gradients and surface roughness of the intermetallic layer which may explain the different tin whiskering properties. It was observed that the intermetallic layer growth mechanisms are completely different in the Ag barrier layers compared to the Ni layers. In the case of Sn/Ag/Cu systems, the Sn and Cu diffused through the Ag layer, formed Cu 6 Sn 5 intermetallics mainly at the Sn/Ag interface and consumed the Ag barrier layer. - Highlights: • Intermetallic growth was characterised in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. • Intermetallic growth rates and roughness are similar in the Sn/Cu and Sn/Ni/Cu systems. • Sn/Ni/Cu system contains the following intermetallic layer structure Sn–Ni3Sn4–Ni3Sn2–Ni3Sn–Ni. • In the case of Sn/Ag/Cu systems the Sn and Cu diffusion consumes the Ag barrier layer. • When Cu reaches the Sn/Ag interface a large amount of Cu 6 Sn 5 forms above the Ag layer

  7. Negative mass

    International Nuclear Information System (INIS)

    Hammond, Richard T

    2015-01-01

    Some physical aspects of negative mass are examined. Several unusual properties, such as the ability of negative mass to penetrate any armor, are analysed. Other surprising effects include the bizarre system of negative mass chasing positive mass, naked singularities and the violation of cosmic censorship, wormholes, and quantum mechanical results as well. In addition, a brief look into the implications for strings is given. (paper)

  8. Ethanol electrooxidation on novel carbon supported Pt/SnOx/C catalysts with varied Pt:Sn ratio

    International Nuclear Information System (INIS)

    Jiang, L.; Colmenares, L.; Jusys, Z.; Sun, G.Q.; Behm, R.J.

    2007-01-01

    Novel carbon supported Pt/SnO x /C catalysts with Pt:Sn atomic ratios of 5:5, 6:4, 7:3 and 8:2 were prepared by a modified polyol method and characterized with respect to their structural properties (X-ray diffraction (XRD) and transmission electron microscopy (TEM)), chemical composition (XPS), their electrochemical properties (base voltammetry, CO ad stripping) and their electrocatalytic activity and selectivity for ethanol oxidation (ethanol oxidation reaction (EOR)). The data show that the Pt/SnO x /C catalysts are composed of Pt and tin oxide nanoparticles with an average Pt particle diameter of about 2 nm. The steady-state activity of the Pt/SnO x /C catalysts towards the EOR decreases with tin content at room temperature, but increases at 80 deg. C. On all Pt/SnO x /C catalysts, acetic acid and acetaldehyde represent dominant products, CO 2 formation contributes 1-3% for both potentiostatic and potentiodynamic reaction conditions. With increasing potential, the acetaldehyde yield decreases and the acetic acid yield increases. The apparent activation energies of the EOR increase with tin content (19-29 kJ mol -1 ), but are lower than on Pt/C (32 kJ mol -1 ). The somewhat better performance of the Pt/SnO x /C catalysts compared to alloyed PtSn x /C catalysts is attributed to the presence of both sufficiently large Pt ensembles for ethanol dehydrogenation and C-C bond splitting and of tin oxide for OH generation. Fuel cell measurements performed for comparison largely confirm the results obtained in model studies

  9. Assay Validation For Quantitation of Sn 2+ In Radiopharmaceutical Kits

    International Nuclear Information System (INIS)

    Muthalib, A; Ramli, Martalena; Herlina; Sarmini, Endang; Suharmadi; Besari, Canti

    1998-01-01

    An assay validation for quantitation of Sn2+ in radiopharmaceutical kits based on indirect iodometric titration is described. The method is based on the oxidation of sn2+ using a known excess of iodine and the excess unreacted iodine titrated with thiosulphate. Typical analytical parameters considered in this assay validation are precision, accuracy, selectivity or specificity, range, and linearity. The precision of the analytical method is quit good represented by coefficient of variance in range of 1.0% to 6.9 %, for 10 runs of analysis except one analysis shows the coefficient of 10.2 %. The method has an accuracy of 95.6 % - 99 % as percent recoveries at theoretical Sn2+ amounts of 463 μg to 2318μg

  10. Diffusion and chemical activity of Zr-Sn and Zr-Ti systems

    International Nuclear Information System (INIS)

    Zee, R.H.; Watters, J.F.; Davidson, R.D.

    1986-01-01

    A modified evaporation method was used to determine the diffusion coefficients and the emission rates of Sn and Ti in Zr-Sn and Zr-Ti, respectively, at temperatures between 1605 and 1970 K. Results show that both Sn and Ti diffuse in their respective alloys via a vacancy mechanism. Comparison with data in the literature reveals that the activation energy for diffusion of Sn in Zr-Sn, with Sn content between 3 and 5 at.X is relatively constant from 1200 to 1970 K. From the measured emission rates, values of 103 and 98 kcal/mol were obtained for the enthalpies of sublimation for Sn and Ti in their alloys. With a comparison of the solute vapor pressures with those of the pure elements, partial molar free energies, entropies, and enthalpies for the two systems were determined in the temperature range investigated. The Zr-Sn system shows a very large negative heat of formation (-33 kcal/mol) whereas the Zr-Ti system behaves quite ideally, in agreement with phase-diagram predictions

  11. Negative Leadership

    Science.gov (United States)

    2013-03-01

    Negative Leadership by Colonel David M. Oberlander United States Army United States Army War...SUBTITLE Negative Leadership 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Colonel David M...Dr. Richard C. Bullis Department of Command Leadership , and Management 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING

  12. Negative liability

    NARCIS (Netherlands)

    Dari-Mattiacci, G.

    2009-01-01

    Negative and positive externalities pose symmetrical problems to social welfare. The law internalizes negative externalities by providing general tort liability rules. According to such rules, those who cause harm to others should pay compensation. In theory, in the presence of positive

  13. Negative ... concord?

    NARCIS (Netherlands)

    Giannakidou, A

    The main claim of this paper is that a general theory of negative concord (NC) should allow for the possibility of NC involving scoping of a universal quantifier above negation. I propose that Greek NC instantiates this option. Greek n-words will be analyzed as polarity sensitive universal

  14. PROTEUS-SN User Manual

    Energy Technology Data Exchange (ETDEWEB)

    Shemon, Emily R. [Argonne National Lab. (ANL), Argonne, IL (United States); Smith, Micheal A. [Argonne National Lab. (ANL), Argonne, IL (United States); Lee, Changho [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-02-16

    PROTEUS-SN is a three-dimensional, highly scalable, high-fidelity neutron transport code developed at Argonne National Laboratory. The code is applicable to all spectrum reactor transport calculations, particularly those in which a high degree of fidelity is needed either to represent spatial detail or to resolve solution gradients. PROTEUS-SN solves the second order formulation of the transport equation using the continuous Galerkin finite element method in space, the discrete ordinates approximation in angle, and the multigroup approximation in energy. PROTEUS-SN’s parallel methodology permits the efficient decomposition of the problem by both space and angle, permitting large problems to run efficiently on hundreds of thousands of cores. PROTEUS-SN can also be used in serial or on smaller compute clusters (10’s to 100’s of cores) for smaller homogenized problems, although it is generally more computationally expensive than traditional homogenized methodology codes. PROTEUS-SN has been used to model partially homogenized systems, where regions of interest are represented explicitly and other regions are homogenized to reduce the problem size and required computational resources. PROTEUS-SN solves forward and adjoint eigenvalue problems and permits both neutron upscattering and downscattering. An adiabatic kinetics option has recently been included for performing simple time-dependent calculations in addition to standard steady state calculations. PROTEUS-SN handles void and reflective boundary conditions. Multigroup cross sections can be generated externally using the MC2-3 fast reactor multigroup cross section generation code or internally using the cross section application programming interface (API) which can treat the subgroup or resonance table libraries. PROTEUS-SN is written in Fortran 90 and also includes C preprocessor definitions. The code links against the PETSc, METIS, HDF5, and MPICH libraries. It optionally links against the MOAB library and

  15. Study of GeSn Alloy for Low Cost Monolithic Mid Infrared Quantum Well Sensor

    Directory of Open Access Journals (Sweden)

    Prakash PAREEK

    2017-02-01

    Full Text Available This paper focuses on theoretical study of Tin incorporated group IV alloys particularly GeSn and design of quantum well sensor for mid infrared sensing applications. Initially, the physics behind the selection of material for midinfrared sensor is explained. The importance of controlling strain in GeSn alloy is also explained. The physical background and motivation for incorporation of Tin(Sn in Germanium is briefly narrated. Eigen energy states for different Sn concentrations are obtained for strain compensated quantum well in G valley conduction band (GCB, heavy hole (HH band and light hole (LH band by solving coupled Schrödinger and Poisson equations simultaneously. Sn concentration dependent absorption spectra for HH- GCB transition reveals that significant absorption observed in mid infrared range (3-5 µm. So, Ge1-x Snx quantum well can be used for mid infrared sensing applications.

  16. Sn whiskers removed by energy photo flashing

    International Nuclear Information System (INIS)

    Jiang, N.; Yang, M.; Novak, J.; Igor, P.; Osterman, M.

    2012-01-01

    Highlights: ► Sn whiskers were sintered by intense light flashing (Photosintering). ► Photosintering can effectively eliminate Sn whiskers. ► Photosintering would not damage electronic devices. ► Photosintering is a very promising approach to improve Sn-based electronic surface termination. - Abstract: Sn whiskers have been known to be the major issue resulting in electronic circuit shorts. In this study, we present a novel energy photo flashing approach (photosintering) to shorten and eliminate Sn whiskers. It has been found that photosintering is very effective to modify and remove Sn whiskers; only a sub-millisecond duration photosintering can amazingly get rid of over 90 vol.% of Sn whiskers. Moreover, this photosintering approach has also been proved to cause no damages to electronic devices, suggesting it is a potentially promising way to improve Sn-based electronic surface termination.

  17. La5Zn2Sn

    Directory of Open Access Journals (Sweden)

    Igor Oshchapovsky

    2011-11-01

    Full Text Available A single crystal of pentalanthanum dizinc stannide, La5Zn2Sn, was obtained from the elements in a resistance furnace. It belongs to the Mo5SiB2 structure type, which is a ternary ordered variant of the Cr5B3 structure type. The space is filled by bicapped tetragonal antiprisms from lanthanum atoms around tin atoms sharing their vertices. Zinc atoms fill voids between these bicapped tetragonal antiprisms. All four atoms in the asymmetric unit reside on special positions with the following site symmetries: La1 (..m; La2 (4/m..; Zn (m.2m; Sn (422.

  18. Ordered CoSn-type ternary phases in Co3Sn3-xGex

    DEFF Research Database (Denmark)

    Allred, Jared M.; Jia, Shuang; Bremholm, Martin

    2012-01-01

    . By taking advantage of the chemical differences between the two crystallographically inequivalent Sn sites in the structure, we observe ordered ternary phases, nominally Co3SnGe2 and Co3Sn2Ge. The electron count and unit cell configuration remain unchanged from CoSn; these observations thus help to clarify...

  19. Fabrication of textured SnO2 transparent conductive films using self-assembled Sn nanospheres

    Science.gov (United States)

    Fukumoto, Michitaka; Nakao, Shoichiro; Hirose, Yasushi; Hasegawa, Tetsuya

    2018-06-01

    We present a novel method to fabricate textured surfaces on transparent conductive SnO2 films by processing substrates through a bottom-up technique with potential for industrially scalable production. The substrate processing consists of three steps: deposition of precursor Sn films on glass substrates, formation of a self-assembled Sn nanosphere layer with reductive annealing, and conversion of Sn to SnO2 by oxidative annealing. Ta-doped SnO2 films conformally deposited on the self-assembled nanospherical SnO2 templates exhibited attractive optical and electrical properties, namely, enhanced haze values and low sheet resistances, for applications as transparent electrodes in photovoltaics.

  20. Nanocrystalline SnO2 thin films: Structural, morphological, electrical transport and optical studies

    International Nuclear Information System (INIS)

    Sakhare, R.D.; Khuspe, G.D.; Navale, S.T.; Mulik, R.N.; Chougule, M.A.; Pawar, R.C.; Lee, C.S.; Sen, Shashwati; Patil, V.B.

    2013-01-01

    Highlights: ► Novel chemical route of synthesis of SnO 2 films. ► Physical properties SnO 2 are influenced by process temperature. ► The room temperature electrical conductivity of SnO 2 is of 10 −7 –10 −5 (Ω cm) −1 . ► SnO 2 exhibit high absorption coefficient (10 4 cm −1 ). -- Abstract: Sol–gel spin coating method has been successfully employed for preparation of nanocrystalline tin oxide (SnO 2 ) thin films. The effect of processing temperature on the structure, morphology, electrical conductivity, thermoelectric power and band gap was studied using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction pattern, atomic force microscopy, two probe technique and UV–visible spectroscopy. X-ray diffraction (XRD) analysis showed that SnO 2 films are crystallized in the tetragonal phase and present a random orientation. Field emission scanning electron microscopy (FESEM) analysis revealed that surface morphology of the tin oxide film consists nanocrystalline grains with uniform coverage of the substrate surface. Transmission electron microscopy (TEM) of SnO 2 film showed nanocrystals having diameter ranging from 5 to 10 nm. Selected area electron diffraction (SAED) pattern confirms tetragonal phase evolution of SnO 2 . Atomic force microscopy (AFM) analysis showed surface morphology of SnO 2 film is smooth. The dc electrical conductivity showed the semiconducting nature with room temperature electrical conductivity increased from 10 −7 to 10 −5 (Ω cm) −1 as processing temperature increased from 400 to 700 °C. Thermo power measurement confirms n-type conduction. The band gap energy of SnO 2 film decreased from 3.88 to 3.60 eV as processing temperature increased from 400 to 700 °C

  1. Thermodynamic modelling of Li–Sn liquid alloy based on Knudsen effusion mass spectrometric measurements

    International Nuclear Information System (INIS)

    Bencze, L.; Henriques, D.; Motalov, V.; Markus, T.

    2014-01-01

    Highlights: • The experimental KEMS data fit well with the Redlich–Kister sub-regular solution model applied to Li–Sn melt. • The Redlich–Kister binary interaction L-parameters of the Li–Sn melt were provided in this work. • The experimental KEMS data fit well with the ideally associated mixture model, too. • The quantitative associate composition of the Li–Sn melt was given. • The thermodynamic properties of the associate-forming reactions were also provided. - Abstract: The mixing thermodynamic properties of liquid Li–Sn system, determined previously by Knudsen effusion mass spectrometry (KEMS), were successfully fitted to both Redlich–Kister (RK) sub-regular mixture and ideally associated mixture (IAMT) models. The RK binary interaction L parameters, as a function of temperature in the CALPHAD-type functional form, were obtained as follows: L (0) =-(108580±0.00171)+(16.4±1.6·10 -5 )·T+(1.96496·10 -9 ±2.03133·10 -6 ) ·T·ln(T) L (1) =-(96600±4700)+(3.3±43.0)·T+(4.4±5.6)·T·ln(T) L (2) =-(64670±190)-(44.4±1.7)·T+(8.44±0.22)·T·ln(T) L (3) =-(20900±1500)-(29±14)·T+(4.3±1.8)·T·ln(T) The former literature data provided only qualitative information on possible liquid associates but no quantitative associate composition was given as a function of the sample composition and temperature. The experimental KEMS data in the composition range X Li = 0 to ∼0.7 fit well with the Li(l) + Sn(l) + LiSn(l) + LiSn 2 (l) + Li 2 Sn(l) associate model. At X Li > 0.7 no associate variations – including further associate variants such as Li 4 Sn(l) etc. – could be fitted to the KEMS data. Nevertheless, in this work the Li(l) + Sn(l) + LiSn(l) + LiSn 2 (l) + Li 2 Sn(l) + Li 4 Sn(l) + Li 9 Sn(l) associate model was successfully fitted to the thermodynamic data of a selected literature study over the complete composition range. The thermodynamic data of the associate-forming reactions were also given in this paper

  2. Shape-selective Valorization of Biomass-derived Glycolaldehyde using Tin-containing Zeolites

    DEFF Research Database (Denmark)

    Tolborg, Søren; Meier, Sebastian; Shunmugavel, Saravanamurugan

    2016-01-01

    sugars while hindering consecutive aldol reactions leading to hexose sugars. High yields of tetrose sugars (74 %) with minor amounts of vinyl glycolic acid (VGA), an α-hydroxyacid, are obtained using Sn-MFI with selectivities towards C4 products reaching 97 %. Tin catalysts having large pores or no pore...... structure (Sn-Beta, Sn-MCM-41, Sn-SBA-15, tin chloride) led to lower selectivities for C4 sugars due to formation of hexose sugars. In the case of Sn-Beta, VGA is the main product (30 %), illustrating differences in selectivity of the Sn sites in the different frameworks. Under optimized conditions, GA can...

  3. Magnetic behaviour of cerium in Ce2 Sn5 and Ce3 Sn7, surstructures of Ce Sn3

    International Nuclear Information System (INIS)

    Stunault, A.

    1988-07-01

    The compound studied, Ce 2 Sn 5 and Ce 3 Sn 7 are both orthorhombic, surstructure of cubic Ce Sn 3 . Magnetic susceptibility measurements show in both compounds an antiferromagnetic order at low temperature and magnetization shows a high anisotropy. Magnetization densities are determined by polarized neutron diffraction. The cerium site which has two Ce atoms as nearest neighbourgs carries all the magnetism in both structures. For Ce 2 Sn 5 moments are directed as the high magnetization axis and structure is modulated. Ce 3 Sn 7 presents a simple antiferromagnetic order but moment are directed as low magnetization axis. Various transitions towards a ferromagnetic order are presented. Results are interpreted by measuring the difference between energy levels of crystalline field. A model of crystalline field and isotrope exchange agrees well with Ce 3 Sn 7 , but for Ce 2 Sn 7 it is necessary to reduce the magnetic moment which is typical of the Kondo effect [fr

  4. Surface reaction of SnII on goethite (α-FeOOH): surface complexation, redox reaction, reductive dissolution, and phase transformation.

    Science.gov (United States)

    Dulnee, Siriwan; Scheinost, Andreas C

    2014-08-19

    To elucidate the potential risk of (126)Sn migration from nuclear waste repositories, we investigated the surface reactions of Sn(II) on goethite as a function of pH and Sn(II) loading under anoxic condition with O2 level redox state and surface structure were investigated by Sn K edge X-ray absorption spectroscopy (XAS), goethite phase transformations were investigated by high-resolution transmission electron microscopy and selected area electron diffraction. The results demonstrate the rapid and complete oxidation of Sn(II) by goethite and formation of Sn(IV) (1)E and (2)C surface complexes. The contribution of (2)C complexes increases with Sn loading. The Sn(II) oxidation leads to a quantitative release of Fe(II) from goethite at low pH, and to the precipitation of magnetite at higher pH. To predict Sn sorption, we applied surface complexation modeling using the charge distribution multisite complexation approach and the XAS-derived surface complexes. Log K values of 15.5 ± 1.4 for the (1)E complex and 19.2 ± 0.6 for the (2)C complex consistently predict Sn sorption across pH 2-12 and for two different Sn loadings and confirm the strong retention of Sn(II) even under anoxic conditions.

  5. Clinical results of sentinel lymph node (SN) biopsy for oral cancer. Relationship between SN localization and metastasis in tongue cancer

    International Nuclear Information System (INIS)

    Shintani, Satoru; Nakashiro, Koh-ichi; Hino, Satoshi; Terakado, Nagaaki; Hamakawa, Hiroyuki

    2005-01-01

    Attempts were made to detect micrometastasis in N0 neck of oral cancer patients using sentinel lymph node (SN) biopsy (SNB). We previously described our approach to identify SN using a radioisotope ( 99m Tc-Tin colloid)-guided and dye-guided method. Micrometastases were detected by means of serial sections and real-time polymerase chain reaction (PCR) based on squamous cell carcinoma (SCC) antigen mRNA. In this study, we evaluated the radiolocalization of SN and identification of metastatic lymph node in N0 oral cancer patients. The positive rate of metastatic lymph node in N0 oral cancer was 35% and the diagnostic sensitivity of SNB was 95%. The SNB detected subclinical metastases in 4 of 10 N0 patients with tongue cancer. Moreover, in 3 of these 4 cases, all metastatic lymph nodes consisted with SNs. Postoperative cervical metastasis was observed in a patient whose SNB was negative. While more experience is needed, we believe the SN concept for tongue cancer is established, and practical application in clinical settings is anticipated. (author)

  6. Negative CO

    NARCIS (Netherlands)

    Meysman, F.J.R.; Montserrat, F.

    2017-01-01

    Negative emission technologies (NETs) target the removal of carbon dioxide (CO2) from the atmosphere, and are being actively investigated as a strategy to limit global warming to within the 1.5–2°C targets of the 2015 UN climate agreement. Enhanced silicate weathering (ESW) proposes to

  7. Negative Certainty

    Science.gov (United States)

    Ariso, José María

    2017-01-01

    The definitions of "negative knowledge" and the studies in this regard published to date have not considered the categorial distinction Wittgenstein established between knowledge and certainty. Hence, the important role that certainty, despite its omission, should have in these definitions and studies has not yet been shown. In this…

  8. Improvement of aging kinetics and precipitate size refinement in Mg–Sn alloys by hafnium additions

    Energy Technology Data Exchange (ETDEWEB)

    Behdad, S. [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Zhou, L. [Department of Materials Science and Engineering and Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816 (United States); Henderson, H.B.; Manuel, M.V. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Sohn, Y. [Department of Materials Science and Engineering and Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816 (United States); Agarwal, A. [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Boesl, B., E-mail: bboesl@fiu.edu [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States)

    2016-01-10

    Two Mg–Sn alloys were microalloyed by addition of Hafnium and their age-hardening response was studied at 200 °C. Time to reach peak hardness was significantly reduced and improved by Hf addition. TEM study showed Hf clusters in the close vicinity and at the surface of Mg{sub 2}Sn precipitates, which confirms that Hf clusters act as additional nucleation centers for Mg{sub 2}Sn precipitate formation. Our results support the validity of thermokinetic criterion proposed by Mendis for selection of microalloying elements in order to refine precipitate size, accelerate aging kinetics and enhance peak hardness.

  9. CHROMagar COL-APSE: a selective bacterial culture medium for the isolation and differentiation of colistin-resistant Gram-negative pathogens

    DEFF Research Database (Denmark)

    Abdul Momin, Muhd Haziq F; Bean, David C; Hendriksen, Rene S.

    2017-01-01

    Purpose. A selective chromogenic culture medium for the laboratory isolation and differentiation of colistin resistant Acinetobacter, Pseudomonas, Stenotrophomonas and Enterobacteriaceae spp. (CHROMagar COL-APSE) was developed, evaluated and compared to an existing selective bacterial culture......-resistant non-fermentative bacteria (Acinetobacter, Pseudomonas and Stenotrophomonas). CHROMagar COL-APSE was also more sensitive in supporting the growth of Enterobacteriaceae with COL resistance associated with the carriage of mcr-1. Conclusion. CHROMagar COL-APSE is a sensitive and specific medium...

  10. Chemotherapeutic agents attenuate CXCL12-mediated migration of colon cancer cells by selecting for CXCR4-negative cells and increasing peptidase CD26

    International Nuclear Information System (INIS)

    Cutler, Murray J.; Lowthers, Erica L.; Richard, Cynthia L.; Hajducek, Dagmar M.; Spagnuolo, Paul A.; Blay, Jonathan

    2015-01-01

    Recurrence of colorectal cancer (CRC) may arise due to the persistence of drug-resistant and cancer-initiating cells that survive exposure to chemotherapy. Proteins responsible for this recurrence include the chemokine receptor CXCR4, which is known to enable CRC metastasis, as well as the cancer-initiating cell marker and peptidase CD26, which terminates activity of its chemokine CXCL12. We evaluated the expression and function of CXCR4 and CD26 in colon cancer cell lines and xenografts following treatment with common chemotherapies using radioligand binding, flow cytometry, immunofluorescence, and enzymatic assays. 5-Fluorouracil, oxaliplatin and SN-38 (the active metabolite of irinotecan), as well as cisplatin, methotrexate and vinblastine, each caused decreases in cell-surface CXCR4 and concomitant increases in CD26 on HT-29, T84, HRT-18, SW480 and SW620 CRC cell lines. Flow cytometry indicated that the decline in CXCR4 was associated with a significant loss of CXCR4+/CD26- cells. Elevations in CD26 were paralleled by increases in both the intrinsic dipeptidyl peptidase activity of CD26 as well as its capacity to bind extracellular adenosine deaminase. Orthotopic HT-29 xenografts treated with standard CRC chemotherapeutics 5-fluorouracil, irinotecan, or oxaliplatin showed dramatic increases in CD26 compared to untreated tumors. Consistent with the loss of CXCR4 and gain in CD26, migratory responses to exogenous CXCL12 were eliminated in cells pretreated with cytotoxic agents, although cells retained basal motility. Analysis of cancer-initiating cell CD44 and CD133 subsets revealed drug-dependent responses of CD26/CD44/CD133 populations, suggesting that the benefits of combining standard chemotherapies 5-fluoruracil and oxaliplatin may be derived from their complementary elimination of cell populations. Our results indicate that conventional anticancer agents may act to inhibit chemokine-mediated migration through eradication of CXCR4+ cells and attenuation of

  11. Decolorization of Methylene Blue by Ag/SrSnO3 Composites under Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    Patcharanan Junploy

    2014-01-01

    Full Text Available SrSn(OH6 precursors synthesized by a cyclic microwave radiation (CMR process were calcined at 900°C for 3 h to form rod-like SrSnO3. Further, the rod-like SrSnO3 and AgNO3 in ethylene glycol (EG were ultrasonically vibrated to form rod-like Ag/SrSnO3 composites, characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, electron microscopy (EM, Fourier transform infrared (FTIR spectroscopy, and UV-visible analysis. The photocatalyses of rod-like SrSnO3, 1 wt%, 5 wt%, and 10 wt% Ag/SrSnO3 composites were studied for degradation of methylene blue (MB, C16H18N3SCl dye under ultraviolet (UV radiation. In this research, the 5 wt% Ag/SrSnO3 composites showed the highest activity, enhanced by the electron-hole separation process. The photoactivity became lower by the excessive Ag nanoparticles due to the negative effect caused by reduction in the absorption of UV radiation.

  12. Sup(99m)Tc-Sn-pyrophosphate complex. A stable, lyophilized radiopharmaceutical for skeletal scanning

    Energy Technology Data Exchange (ETDEWEB)

    Cvoric, J; Jovanovic, V; Bzenic, J [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia); Stefanovic, Lj; Selir, Z [Institute for Tuberculosis and Pectoral Diseases, Radioisotope Applications, Sremska Kamenica (Yugoslavia)

    1978-01-01

    After a systematic investigation of the different phosphate polymers, viz. hexametaphosphate, tripolyphosphate, meta- and diphosphonate, pyrophosphate (Na/sub 4/P/sub 2/O/sub 7/) was selected for sceletal scintigraphy. A procedure has been developed for obtaining a sup(99m)Tc-labelled Sn(II): PyP complex by addition of a sterile, apyrogenic pertechnetate solution from a sup(99m)Tc-generator to a lyophilized solution of Sn(II)-tetrasodium phosphate. ''Kit'' composition was determined on the basis of biodynamic data obtained when the Sn/pyrophosphate ratio, pH and other parameters were varied. In vivo distribution of different sup(99m)Tc-Sn-pyrophosphate complexes permitted the selection of the most suitable complex for sceletal scanning. The investigated complex is being successfully applied in human scintigraphy of bones in the Laboratory for Radioisotope Applications of the Institute for Tubercolosis and Pectoral Diseases in Sremska Kamenica.

  13. Multicenter Evaluation of a New Shortened Peptide Nucleic Acid Fluorescence In Situ Hybridization Procedure for Species Identification of Select Gram-Negative Bacilli from Blood Cultures▿

    Science.gov (United States)

    Morgan, Margie; Marlowe, Elizabeth; Della-Latta, Phyllis; Salimnia, Hossein; Novak-Weekley, Susan; Wu, Fann; Crystal, Benjamin S.

    2010-01-01

    A shortened protocol for two peptide nucleic acid fluorescence in situ hybridization (PNA FISH) assays for the detection of Gram-negative bacilli from positive blood cultures was evaluated in a multicenter trial. There was 100% concordance between the two protocols for each assay (368 of 368 and 370 of 370 results) and 99.7% (367 of 368 and 369 of 370 results) agreement with routine laboratory techniques. PMID:20357212

  14. The Impact of Efflux Pump Inhibitors on the Activity of Selected Non-Antibiotic Medicinal Products against Gram-Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Agnieszka E. Laudy

    2017-01-01

    Full Text Available The potential role of non-antibiotic medicinal products in the treatment of multidrug-resistant Gram-negative bacteria has recently been investigated. It is highly likely that the presence of efflux pumps may be one of the reasons for the weak activity of non-antibiotics, as in the case of some non-steroidal anti-inflammatory drugs (NSAIDs, against Gram-negative rods. The activity of eight drugs of potential non-antibiotic activity, active substance standards, and relevant medicinal products were analysed with and without of efflux pump inhibitors against 180 strains of five Gram-negative rod species by minimum inhibitory concentration (MIC value determination in the presence of 1 mM MgSO4. Furthermore, the influence of non-antibiotics on the susceptibility of clinical strains to quinolones with or without PAβN (Phe-Arg-β-naphthylamide was investigated. The impacts of PAβN on the susceptibility of bacteria to non-antibiotics suggests that amitriptyline, alendronate, nicergoline, and ticlopidine are substrates of efflux pumps in Gram-negative rods. Amitriptyline/Amitriptylinum showed the highest direct antibacterial activity, with MICs ranging 100–800 mg/L against all studied species. Significant decreases in the MIC values of other active substances (acyclovir, atorvastatin, and famotidine tested with pump inhibitors were not observed. The investigated non-antibiotic medicinal products did not alter the MICs of quinolones in the absence and in the presence of PAβN to the studied clinical strains of five groups of species.

  15. Electronic structure and isomer shifts of Sn halides

    International Nuclear Information System (INIS)

    Terra, J.; Guenzburger, D.

    1988-01-01

    The all-electron first-principles Discrete Variational method was employed to study the electronic structure of SnF 4 , SnCl 4 , SnBr 4 and SnI 4 . Values of the electronic density at the Sn nucleus were derived and related to 119 Sn Isomer Shifts to obtain the nuclear constant Δ 2 >. Differences in values of ρ(o) area discussed in terms of the chemical bonding between Sn and halogen atoms. (author) [pt

  16. The transgenerational effects of heat stress in the nematode Caenorhabditis remanei are negative and rapidly eliminated under direct selection for increased stress resistance in larvae.

    Science.gov (United States)

    Sikkink, Kristin L; Ituarte, Catherine M; Reynolds, Rose M; Cresko, William A; Phillips, Patrick C

    2014-12-01

    Parents encountering stress environments can influence the phenotype of their offspring in a form of transgenerational phenotypic plasticity that has the potential to be adaptive if offspring are thereby better able to deal with future stressors. Here, we test for the existence of anticipatory parental effects in the heat stress response in the highly polymorphic nematode Caenorhabditis remanei. Rather providing an anticipatory response, parents subject to a prior heat stress actually produce offspring that are less able to survive a severe heat shock. Selection on heat shock resistance within the larvae via experimental evolution leads to a loss of sensitivity (robustness) to environmental variation during both the parental and larval periods. Whole genome transcriptional analysis of both ancestor and selected lines shows that there is weak correspondence between genetic pathways induced via temperature shifts during parental and larval periods. Parental effects can evolve very rapidly via selection acting directly on offspring. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Pseudomorphic GeSiSn, SiSn and Ge layers in strained heterostructures

    Science.gov (United States)

    Timofeev, V. A.; Nikiforov, A. I.; Tuktamyshev, A. R.; Mashanov, V. I.; Loshkarev, I. D.; Bloshkin, A. A.; Gutakovskii, A. K.

    2018-04-01

    The GeSiSn, SiSn layer growth mechanisms on Si(100) were investigated and the kinetic diagrams of the morphological GeSiSn, SiSn film states in the temperature range of 150 °C-450 °C at the tin content from 0% to 35% were built. The phase diagram of the superstructural change on the surface of Sn grown on Si(100) in the annealing temperature range of 0 °C-850 °C was established. The specular beam oscillations were first obtained during the SiSn film growth from 150 °C to 300 °C at the Sn content up to 35%. The transmission electron microscopy and x-ray diffractometry data confirm the crystal perfection and the pseudomorphic GeSiSn, SiSn film state, and also the presence of smooth heterointerfaces between GeSiSn or SiSn and Si. The photoluminescence for the multilayer periodic GeSiSn/Si structures in the range of 0.6-0.8 eV was detected. The blue shift with the excitation power increase is observed suggesting the presence of a type II heterostructure. The creation of tensile strained Ge films, which are pseudomorphic to the underlying GeSn layer, is confirmed by the results of the formation and analysis of the reciprocal space map in the x-ray diffractometry. The tensile strain in the Ge films reached the value in the range of 0.86%-1.5%. The GeSn buffer layer growth in the Sn content range from 8% to 12% was studied. The band structure of heterosystems based on pseudomorphic GeSiSn, SiSn and Ge layers was calculated and the valence and conduction band subband position dependences on the Sn content were built. Based on the calculation, the Sn content range in the GeSiSn, SiSn, and GeSn layers, which corresponds to the direct bandgap GeSiSn, SiSn, and Ge material, was obtained.

  18. Effects of interlayer Sn-Sn lone pair interaction on the band gap of bulk and nanosheet SnO

    Science.gov (United States)

    Umezawa, Naoto; Zhou, Wei

    2015-03-01

    Effects of interlayer lone-pair interactions on the electronic structure of SnO are firstly explored by the density-functional theory. Our comprehensive study reveals that the band gap of SnO opens as increase in the interlayer Sn-Sn distance. The effect is rationalized by the character of band edges which consists of bonding and anti-bonding states from interlayer lone pair interactions. The band edges for several nanosheets and strained double-layer SnO are estimated. We conclude that the double-layer SnO is a promising material for visible-light driven photocatalyst for hydrogen evolution. This work is supported by the Japan Science and Technology Agency (JST) Precursory Research for Embryonic Science and Technology (PRESTO) program.

  19. Efficient and selective heavy metal sequestration from water by using layered sulfide K 2x Sn 4-x S 8-x (x = 0.65–1; KTS-3)

    Energy Technology Data Exchange (ETDEWEB)

    Sarma, Debajit; Islam, Saiful M.; Subrahmanyam, K. S.; Kanatzidis, Mercouri G.

    2016-09-16

    Heavy metal ions (Cd2+, Hg2+, As3+ and Pb2+) are an important contributor to the contamination of groundwater and other water bodies in and around industrial areas. Herein, we demonstrate the rapid and efficient capacity of a layered metal sulfide material, K2xSn4-xS8-x (x = 0.65-1, KTS-3) for heavy metal ion removal from water. The effect of concentration, pH, kinetics, and competitive ions such as Na+/Ca2+ on the heavy metal ion removal capacity of KTS-3 was systematically investigated. X-ray photoelectron spectroscopy (XPS), elemental analyses, and powder X-ray diffraction studies revealed that the heavy metal ion-exchange of KTS-3 is complete (quantitative replacement of all potassium ions) and topotactic. The heavy metal ion-exchange by using KTS-3 follows the Langmuir-Freundlich model with high exchange capacities, q(m) 205(17) mg g-1 for Cd2+, 372(21) mg g-1 for Hg2+ and 391(89) mg g-1 for Pb2+. KTS-3 retains excellent heavy metal ion-exchange capacity even in very high concentration (1 M) of competing ions (Na+/Ca2+) and also over a broad pH range (2-12). KTS-3 also exhibits very good ion-exchange capacity for precious Ag+ and toxic As3+ ions. The kinetics of heavy metal ion adsorption by KTS-3 are rapid (absorbs all ions within a few minutes). These properties and the environmentally friendly character of KTS-3 make it a promising candidate for sequestration of heavy metal ions from water.

  20. Controlling the antibacterial activity of CuSn thin films by varying the contents of Sn

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yujin; Park, Juyun; Kim, Dong-Woo; Kim, Hakjun; Kang, Yong-Cheol, E-mail: yckang@pknu.ac.kr

    2016-12-15

    Highlights: • We deposit CuSn thin films on a Si substrate with various Cu/Sn ratio. • Antibacterial activities of CuSn thin films increased as the ratio of Cu and the contact time increased. • XPS was utilized to assign the chemical environment of CuSn thin films before and after antibacterial test. - Abstract: We investigated antibacterial activity of CuSn thin films against Gram positive Staphylococcus aureus (S. aureus). CuSn thin films with different Cu to Sn ratios were deposited on Si(100) by radio frequency (RF) magnetron sputtering method using Cu and Sn metal anodes. The film thickness was fixed at 200 nm by varying the sputtering time and RF power on the metal targets. The antibacterial test was conducted in various conditions such as different contact times and Cu to Sn ratios in the CuSn films. The antibacterial activities of CuSn thin films increased as the ratio of Cu and the contact time between the film and bacteria suspension increased execpt in the case of CuSn-83. The oxidation states of Cu and Sn and the chemical composition of CuSn thin films before and after the antibacterial test were investigated by X-ray photoelectron spectroscopy (XPS). When the contact time was fixed, the Cu species was further oxidized as the RF power on Cu target increased. The intensity of Sn 3d decreased with increasing Cu ratio. When the sample was fixed, the peak intensity of Sn 3d decreased as the contact time increased due to the permeation of Sn into the cell.

  1. Combinatorial investigation of Pt-Ru-Sn alloys as an anode electrocatalysts for direct alcohol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Young Hwan [Department of New Energy.Resource Engineering, College of Science and Engineering, Sangji University, 124, Sangjidae-gil, Wonju-si, Gangwon-Do 220-702 (Korea); Shul, Yong Gun [Department of Chemical and Biomolecular Engineering, Yonsei University, 134, Shinchon-Dong, Seodaemun-Gu, Seoul 120-749 (Korea)

    2010-10-15

    Low-temperature direct alcohol fuel cells fed with different kinds of alcohol (methanol, ethanol and 2-propanol) have been investigated by employing ternary electrocatalysts (Pt-Ru-Sn) as anode catalysts. Combinatorial chemistry has been applied to screen the 66-PtRuSn-anode arrays at the same time to reduce cost, time, and effort when we select the optimum composition of electrocatalysts for DAFCs (Direct Alcohol Fuel Cells). PtRuSn (80:20:0) showed the lowest onset potential for methanol electro-oxidation, PtRuSn (50:0:50) for ethanol, and PtRuSn (20:70:10) for 2-propanol in CV results respectively, and single cell performance test indicated that Ru is more suitable for direct methanol fuel cell system, Sn for direct ethanol fuel cell system, and 2-propanol could be applied as fuel with low platinum composition anode electrocatalyst. The single cell performance results and electrochemical results (CV) were well matched with the combinatorial electrochemical results. As a result, we could verify the availability of combinatorial chemistry by comparing the results of each extreme electrocatalysts compositions as follows: PtRuSn (80:20:0) for methanol, PtRuSn (50:0:50) for ethanol and PtRuSn (20:70:10) for 2-propanol. (author)

  2. Preparation of SnO{sub 2}-CNTs supported Pt catalysts and their electrocatalytic properties for ethanol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Pang, H.L.; Lu, J.P. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Chen, J.H. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)], E-mail: chenjinhua@hnu.cn; Huang, C.T.; Liu, B.; Zhang, X.H. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2009-03-30

    SnO{sub 2}-carbon nanotubes (CNTs) composites were prepared by sol-gel method, and characterized by scanning electron microscopy and X-ray diffraction. Due to high stability in diluted acidic solution, SnO{sub 2}-CNTs composites were selected as the catalyst support and second catalyst for ethanol electrooxidation. The electrocatalytic properties of the SnO{sub 2}-CNTs supported platinum (Pt) catalyst (Pt/SnO{sub 2}-CNTs) for ethanol oxidation have been investigated by typical electrochemical methods. Under the same mass loading of Pt, the Pt/SnO{sub 2}-CNTs catalyst shows higher electrocatalytic activity and better long-term cycle stability than Pt/SnO{sub 2} catalyst. Additionally, the effect of the mass ratio of CNTs to SnO{sub 2} on the electrocatalytic activity of the electrode for ethanol oxidation was investigated, and the optimum mass ratio of CNTs to SnO{sub 2} in the Pt/SnO{sub 2}-CNTs catalyst is 1/6.3.

  3. Spatially selective depleting tumor-associated negative regulatory T-(Treg) cells with near infrared photoimmunotherapy (NIR-PIT): A new cancer immunotherapy (Conference Presentation)

    Science.gov (United States)

    Kobayashi, Hisataka

    2017-02-01

    Near infrared photoimmunotherapy (NIR-PIT) is a new type of molecularly-targeted photo-therapy based on conjugating a near infrared silica-phthalocyanine dye, IR700, to a monoclonal antibody (MAb) targeting target-specific cell-surface molecules. When exposed to NIR light, the conjugate rapidly induces a highly-selective cell death only in receptor-positive, MAb-IR700-bound cells. Current immunotherapies for cancer seek to modulate the balance among different immune cell populations, thereby promoting anti-tumor immune responses. However, because these are systemic therapies, they often cause treatment-limiting autoimmune adverse effects. It would be ideal to manipulate the balance between suppressor and effector cells within the tumor without disturbing homeostasis elsewhere in the body. CD4+CD25+Foxp3+ regulatory T cells (Tregs) are well-known immune-suppressor cells that play a key role in tumor immuno-evasion and have been the target of systemic immunotherapies. We used CD25-targeted NIR-PIT to selectively deplete Tregs, thus activating CD8+ T and NK cells and restoring local anti-tumor immunity. This not only resulted in regression of the treated tumor but also induced responses in separate untreated tumors of the same cell-line derivation. We conclude that CD25-targeted NIR-PIT causes spatially selective depletion of Tregs, thereby providing an alternative approach to cancer immunotherapy that can treat not only local tumors but also distant metastatic tumors.

  4. SN1987A's Twentieth Anniversary

    Science.gov (United States)

    2007-02-01

    Looking back at 20 Years of Observations of this Supernova with ESO telescopes The unique supernova SN 1987A has been a bonanza for astrophysicists. It provided several observational 'firsts,' like the detection of neutrinos from an exploding star, the observation of the progenitor star on archival photographic plates, the signatures of a non-spherical explosion, the direct observation of the radioactive elements produced during the blast, observation of the formation of dust in the supernova, as well as the detection of circumstellar and interstellar material. ESO PR Photo 08a/07 ESO PR Photo 08a/07 SN1987A in the Large Magellanic Cloud Today, it is exactly twenty years since the explosion of Supernova 1987A in the Large Magellanic Cloud was first observed, at a distance of 163,000 light-years. It was the first naked-eye supernova to be seen for 383 years. Few events in modern astronomy have met with such an enthusiastic response by the scientists and now, after 20 years, it continues to be an extremely exciting object that is further studied by astronomers around the world, in particular using ESO's telescopes. When the first signs of Supernova 1987A, the first supernova of the year 1987, were noticed early on 24 February of that year, it was clear that this would be an unusual event. It was discovered by naked-eye and on a panoramic photographic plate taken with a 10-inch astrograph on Las Campanas in Chile by Oscar Duhalde and Ian Shelton, respectively. A few hours earlier, still on 23 February, two large underground detectors - in Japan and the USA - had registered the passage of high-energy neutrinos. Since SN 1987A exploded in the Large Magellanic Cloud (LMC), it was only accessible to telescopes in the Southern Hemisphere, more particularly in Australia, South Africa, and South America. In Chile, ESO's observatory at La Silla with its armada of telescopes with sizes between 0.5 and 3.6-m, played an important role. ESO PR Photo 08c/07 ESO PR Photo 08c/07 The

  5. STRESS a SN survey at ESO

    Science.gov (United States)

    Botticella, M. T.

    We performed the Southern inTermediate Redshift ESO Supernova Search (STRESS), a survey specifically designed to measure the rate of both SNe Ia and CC SNe, in order to obtain a direct comparison of the high redshift and local rates and to investigate the dependence of the rates on specific galaxy properties, most notably their colour. We found that the type Ia SN rate, at mean redshift z = 0.3, is 0.22+0.10+0.16-0.08-0.14 h270 SNu, while the CC SN rate, at z = 0.21, is 0.82+0.31+0.300.24-0.26 h270 SNu. The quoted errors are the statistical and systematic uncertainties. With respect to the local value, the CC SN rate at z = 0.2 is higher by a factor of ˜ 2, whereas the type Ia SN rate remains almost constant. We also measured the SN rates in the red and blue galaxies and found that the SN Ia rate seems to be constant in galaxies of different colour, whereas the CC SN rate seems to peak in blue galaxies, as in the local Universe. Finally we exploited the link between SFH and SN rates to predict the evolutionary behaviour of the SN rates and compare it with the path indicated by observations.

  6. Analyses of the Sn IX-Sn XII spectra in the EUV region

    International Nuclear Information System (INIS)

    Churilov, S S; Ryabtsev, A N

    2006-01-01

    The Sn IX-Sn XII spectra excited in a vacuum spark have been analysed in the 130-160 A wavelength region. The analysis was based on the energy parameter extrapolation in the isonuclear Sn VI-VIII and Sn XIII-XIV sequence. 266 spectral lines belonging to the 4d m -(4d m-1 4f+4p 5 4d m+1 ) (m=6-3) transition arrays were classified in the Sn IX-Sn XII spectra for the first time. All 18 level energies of the 4d 3 configuration and 39 level energies of the strongly interacting 4d 2 4f and 4p 5 4d 4 configurations were established in the Sn XII spectrum. The energy differences between the majority of the 4d m levels and about 40 levels of the 4d m-1 4f+4p 5 4d m+1 configurations were determined in each of the Sn IX, Sn X and Sn XI spectra (m=6-4). As a result, all intense lines were classified in the 130-140 A region relevant to the extreme ultraviolet (EUV) lithography. It was shown that the most of the intense lines in the 2% bandwidth at 135 A belong to the transitions in the Sn XI-Sn XIII spectra

  7. Synthesis of Monodisperse Walnut-Like SnO2 Spheres and Their Photocatalytic Performances

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2015-01-01

    Full Text Available Novel walnut-like SnO2 spheres have been synthesized using a one-step hydrothermal reaction with SnCl2·2H2O and KOH as raw materials. The morphology, microstructure, and optical properties of the products were characterized by X-ray powder diffraction (XRD, Raman spectrum, scanning electron microscopy (SEM, transmission electron microscopy (TEM, selected area electron diffraction (SAED, and ultraviolet-visible (UV-Vis absorption spectroscopy. The detailed studies revealed that these synthesized spheres are highly monodisperse and have a uniform size of approximately 250 nm. Photocatalytic activity of the prepared SnO2 spheres was evaluated by the degradation of methylene orange. The synthesized SnO2 spheres exhibited excellent photocatalytic degradation. In addition, a possible formation mechanism of the walnut-like nanostructures was proposed based on reaction time-dependent experiments.

  8. Detection of Sn(II) ions via quenching of the fluorescence of carbon nanodots

    International Nuclear Information System (INIS)

    Mohd Yazid, S.N.A.; Chin, S.F.; Pang, S.C.; Ng, S.M.

    2013-01-01

    We report that fluorescent carbon nanodots (C-dots) can act as an optical probe for quantifying Sn(II) ions in aqueous solution. C-dots are synthesized by carbonization and surface oxidation of preformed sago starch nanoparticles. Their fluorescence is significantly quenched by Sn(II) ions, and the effect can be used to determine Sn(II) ions. The highest fluorescence intensity is obtained at a concentration of 1.75 mM of C-dots in aqueous solution. The probe is highly selective and hardly interfered by other ions. The quenching mechanism appears to be predominantly of the static (rather than dynamic) type. Under optimum conditions, there is a linear relationship between fluorescence intensity and Sn(II) ions concentration up to 4 mM, and with a detection limit of 0.36 μM. (author)

  9. SnO2 quantum dots with rapid butane detection at lower ppm-level

    Science.gov (United States)

    Cai, Pan; Dong, Chengjun; Jiang, Ming; Shen, Yuanyuan; Tao, You; Wang, Yude

    2018-04-01

    SnO2 quantum dots (QDs) were successfully synthesized by a facile approach employing benzyl alcohol and ammonium hydroxide at lower temperature of 130 °C. It is revealed that the SnO2 QDs is about 3 nm in size to form clusters. The gas sensor based on SnO2 QDs shows a high potential for detecting low-ppm-level butane at 400 °C, exhibiting a high sensitivity, short response and rapid recovery time, and effective selectivity. The sensing mechanism is understood in terms of adsorbed oxygen species. Significantly, the excellent sensing performance is attributed to the smaller size of SnO2 and larger surface area (204.85 m2/g).

  10. Pharmacological characterization and modeling of the binding sites of novel 1,3-bis(pyridinylethynyl)benzenes as metabotropic glutamate receptor 5-selective negative allosteric modulators

    DEFF Research Database (Denmark)

    Mølck, Christina; Harpsøe, Kasper; Gloriam, David E

    2012-01-01

    )pyridine (MPEP)-derived negative allosteric modulators, 2-, 3-, and 4-BisPEB, have been characterized. 2-, 3-, and 4-BisPEB are 1,3-bis(pyridinylethynyl)-benzenes and differ only by the position of the nitrogen atoms in the pyridine rings. Despite their high structural similarity, 2-BisPEB [1,3-bis(pyridin-2......-ylethynyl)-benzene, nitrogen atoms in ortho positions], with an IC(50) value in the nanomolar range, is significantly more potent than the 3- and 4-pyridyl analogs. Mutational analysis, directed by a previously published mGluR5 homology model, was used to determine key residues for the ligand...... that the higher potency of 2-BisPEB is due to hydrogen bonding to Ser809 because the S809A mutation made 2-BisPEB equipotent to 3- and 4-BisPEB (IC(50), 1-2.5 µM). The potency of MPEP was also greatly affected by S809A (52-fold), suggesting that a Ser809-mediated hydrogen bond is also a key interaction between...

  11. Structural and magnetic properties of Mn{sub 50}Fe{sub 50−x}Sn{sub x} (x=10, 15 and 20) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Tanmoy [LCMP, S.N. Bose National Centre for Basic Sciences, Kolkata 700106 (India); Agarwal, Sandeep [Haldia Institute of Technology, Haldia 721657 (India); Mukhopadhyay, P.K., E-mail: pkm@bose.res.in [LCMP, S.N. Bose National Centre for Basic Sciences, Kolkata 700106 (India)

    2016-11-15

    In this work we report measurements and comparisons of the structural, magnetic and transport properties of a series of Mn{sub 50}Fe{sub 50−x}Sn{sub x} alloys (x=10, 15 and 20). We found that while the lower Sn composition sample stabilized in β-Mn-type crystallographic phase, the higher Sn composition alloys contained both β-Mn-type as well as Mn{sub 3}Sn-type hexagonal DO{sub 19} phases. Through d.c. and a.c. magnetic property measurements we have established the existence of a ferromagnetic transition near room temperature followed by a spin reorientation at lower temperature in the Mn{sub 3}Sn-type crystallographic phase of the alloys. Our resistivity study also revealed an interesting behavior with negative temperature coefficient (TCR) in these alloys. - Highlights: • Mn{sub 50}Fe{sub 50-x}Sn{sub x} alloys were studied over a limited concentration range. • Lower Sn alloys behaved similar to ß-Mn alloys both structurally and magnetically. • Higher Sn alloys showed magnetic transitions similar to Mn{sub 3}Sn and Fe{sub 3}Sn. • Resistivity showed bad metallic behavior with negetive temperature coefficient.

  12. Some physico-chemical properties of liquid Ag-Sn-Zn

    International Nuclear Information System (INIS)

    Terzieff, P.

    2010-01-01

    The mean square concentration fluctuations in the long wavelength limit, the surface tension, the segregation behavior and the viscosity of the liquid system Ag-Sn-Zn are calculated in a semi-empirical manner based on experimental thermodynamic data. The increased intensity of fluctuations in the concentration of Sn extending over an wide range of composition is the dominant feature of the system. In a likewise manner, the tendency of segregation into the surface layer is observed to be most noticeable for Sn-atoms. As a consequence, even at massive additions of Ag or Zn up to 60 at% the surface tension is expected not to exceed the value of pure Sn by more than 15%. The viscosities are indicated to increase markedly but in a non-linear manner with the content of Ag. The excess viscosity is found to be negative throughout the system being more pronounced on the Ag-Sn side than on the Ag-Zn or the Sn-Zn side of the system.

  13. Mice with subtle reduction of NMDA NR1 receptor subunit expression have a selective decrease in mismatch negativity: Implications for schizophrenia prodromal population.

    Science.gov (United States)

    Featherstone, Robert E; Shin, Rick; Kogan, Jeffrey H; Liang, Yuling; Matsumoto, Mitsuyuki; Siegel, Steven J

    2015-01-01

    Reductions in glutamate function are regarded as an important contributory factor in schizophrenia. However, there is a paucity of animal models characterized by developmental and sustained reductions in glutamate function. Pharmacological models using NMDA antagonists have been widely used but these typically produce only transient changes in behavior and brain function. Likewise, mice with homozygous constitutive reductions in glutamate receptor expression show stable brain and behavioral changes, but many of these phenotypes are more severe than the human disease. The current study examines a variety of schizophrenia-related EEG measures in mice with a heterozygous alteration of the NMDA receptor NR1 subunit gene (NR1) that is known to result in reduced NR1 receptor expression in the homozygous mouse (NR1-/-). (NR1+/-) mice showed a 30% reduction in NR1 receptor expression and were reared after weaning in either group or isolated conditions. Outcome measures include the response to paired white noise stimuli, escalating inter-stimulus intervals (ISIs) and deviance-related mismatch negativity (MMN). In contrast to what has been reported in (NR1-/-) mice and mice treated with NMDA antagonists, (NR1+/-) mice showed no change on obligatory Event Related Potential (ERP) measures including the murine P50 and N100 equivalents (P20 and N40), or measures of baseline or evoked gamma power. Alternatively, (NR1+/-) mice showed a marked reduction in response to a deviant auditory tone during MMN task. Data suggest that EEG response to deviant, rather than static, stimuli may be more sensitive for detecting subtle changes in glutamate function. Deficits in these heterozygous NR1 knockdown mice are consistent with data demonstrating MMN deficits among family members of schizophrenia patients and among prodromal patients. Therefore, the current study suggests that (NR1+/-) mice may be among the most sensitive models for increased vulnerability to schizophrenia. Copyright

  14. States in 118Sn from 117Sn(d,p) 118Sn at 12 MeV

    International Nuclear Information System (INIS)

    Frota-Pessoa, E.

    1983-01-01

    118 Sn energy levels up to = 5.2 MeV excitation energy are studied in the reaction 117 Sn (d,p) 118 Sn. Deuterons had a bombarding energy of 12 MeV. The protons were analized by a magnetic spectrograph. The detector was nuclear emulsion and the resolution in energy about 10 KeV. The distorted-wave analysis was used to determine l values and spectroscopic strengths. Centers of gravity and the sums of reduced spectroscopic factors are presented for the levels when it was possible to determine the S' value. 66 levels of excitation energy were found which did not appear in previous 117 Sn (d,p) reactions. 40 levels were not found previously in any reaction giving 118 Sn. The results are compared with the known ones. (Author) [pt

  15. Semiconducting ZnSnN{sub 2} thin films for Si/ZnSnN{sub 2} p-n junctions

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Ruifeng [Hebei Engineering Laboratory of Photoelectronic Functional Crystals, Hebei University of Technology (HEBUT), Tianjin 300401 (China); Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, and Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, Ningbo 315201 (China); Cao, Hongtao; Liang, Lingyan, E-mail: lly@nimte.ac.cn, E-mail: swz@hebut.edu.cn; Xie, Yufang; Zhuge, Fei; Zhang, Hongliang; Gao, Junhua; Javaid, Kashif [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, and Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, Ningbo 315201 (China); Liu, Caichi; Sun, Weizhong, E-mail: lly@nimte.ac.cn, E-mail: swz@hebut.edu.cn [Hebei Engineering Laboratory of Photoelectronic Functional Crystals, Hebei University of Technology (HEBUT), Tianjin 300401 (China)

    2016-04-04

    ZnSnN{sub 2} is regarded as a promising photovoltaic absorber candidate due to earth-abundance, non-toxicity, and high absorption coefficient. However, it is still a great challenge to synthesize ZnSnN{sub 2} films with a low electron concentration, in order to promote the applications of ZnSnN{sub 2} as the core active layer in optoelectronic devices. In this work, polycrystalline and high resistance ZnSnN{sub 2} films were fabricated by magnetron sputtering technique, then semiconducting films were achieved after post-annealing, and finally Si/ZnSnN{sub 2} p-n junctions were constructed. The electron concentration and Hall mobility were enhanced from 2.77 × 10{sup 17} to 6.78 × 10{sup 17 }cm{sup −3} and from 0.37 to 2.07 cm{sup 2} V{sup −1} s{sup −1}, corresponding to the annealing temperature from 200 to 350 °C. After annealing at 300 °C, the p-n junction exhibited the optimum rectifying characteristics, with a forward-to-reverse ratio over 10{sup 3}. The achievement of this ZnSnN{sub 2}-based p-n junction makes an opening step forward to realize the practical application of the ZnSnN{sub 2} material. In addition, the nonideal behaviors of the p-n junctions under both positive and negative voltages are discussed, in hope of suggesting some ideas to further improve the rectifying characteristics.

  16. A simple route to Cu{sub x}Sn{sub (100−x)} intermetallic nanoparticle catalyst for ultra-phenol hydroxylation

    Energy Technology Data Exchange (ETDEWEB)

    Pithakratanayothin, Sakollapath [The Petroleum and Petrochemical College and Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok 10330 (Thailand); Tongsri, Ruangdaj [Powder Metallurgy Research and Development Unit - PM-RDU, National Metal and Materials Technology Center, Pathum Thani 12120 (Thailand); Chaisuwan, Thanyalak [The Petroleum and Petrochemical College and Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok 10330 (Thailand); Wongkasemjit, Sujitra, E-mail: dsujitra@chula.ac.th [The Petroleum and Petrochemical College and Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok 10330 (Thailand)

    2016-09-15

    A practical methodology and novel, economical materials were proposed to successfully prepare nanoparticle catalysts for phenol hydroxylation. The preparation was carried out via mechanical alloying (MA) of Cu{sub x}Sn{sub (100−x)} powder mixtures (where x = 30, 50, 70, and 100%wt). The mechanical alloyed nanoparticles were characterized using various techniques. X-ray diffraction patterns indicated that η-Cu{sub 6}Sn{sub 5}, ε-Cu{sub 3}Sn, and CuSn phases could be formed in the mechanical alloyed Cu{sub x}Sn{sub (100−x)} materials. Transmission electron micrographs and selected area electron diffraction patterns confirmed the presence of η-Cu{sub 6}Sn{sub 5}, ε-Cu{sub 3}Sn, and CuSn phases. Activity of the catalysts, using the optimal conditions of 70 °C reaction temperature for 1 h, 50 mg of Cu{sub 0.5}Sn{sub 0.5}, and 1:3 phenol:H{sub 2}O{sub 2} ratio, provided more than 98% conversion with 70% catechol (CAT) and 29% hydroquinone (HQ). Experimental results suggested that the presence of the ε-Cu{sub 3}Sn phase gave higher activity while Sn reduced benzoquinone (BQ) to HQ. The catalyst maintained its stability with no structural collapse for more than 24 h. - Highlights: • Cu{sub x}Sn{sub y} intermetallic as a catalyst was successfully synthesized via mechanical alloying. • Cu{sub x}Sn{sub y} intermetallics promoted impressive phenol hydroxylation. • 98% conversion was achieved with high selectivity of catechol.

  17. SnRK1 activates autophagy via the TOR signaling pathway in Arabidopsis thaliana.

    Science.gov (United States)

    Soto-Burgos, Junmarie; Bassham, Diane C

    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.

  18. Rod-like hierarchical Sn/SnOx@C nanostructures with enhanced lithium storage properties

    Science.gov (United States)

    Yang, Juan; Chen, Sanmei; Tang, Jingjing; Tian, Hangyu; Bai, Tao; Zhou, Xiangyang

    2018-03-01

    Rod-like hierarchical Sn/SnOx@C nanostructures have been designed and synthesized via calcining resorcinol-formaldehyde (RF) resin coated Sn-based metal-organic frameworks. The rod-like hierarchical Sn/SnOx@C nanostructures are made of a great number of carbon-wrapped primary Sn/SnOx nanospheres of 100-200 nm in diameter. The as-prepared hierarchical Sn/SnOx@C nanocomposite manifests a high initial reversible capacity of 1177 mAh g-1 and remains 1001 mAh g-1 after 240 cycles at a current density of 200 mA g-1. It delivers outstanding high-rate performance with a reversible capacity of 823 mAh g-1 even at a high current density of 1000 mA g-1. The enhanced electrochemical performances of the Sn/SnOx@C electrode are mainly attributed to the synergistic effect of the unique hierarchical micro/nanostructures and the protective carbon layer.

  19. Studying superconducting Nb3Sn wire

    CERN Multimedia

    AUTHOR|(CDS)2099575

    2015-01-01

    Studying superconducting Nb3Sn wire. From the current experience from LHC and HL-LHC we know that the performance requirements for Nb3Sn conductor for future circular collider are challenging and should exceed that of present state-of-the-art materials.

  20. Anomalous temperature behavior of Sn impurities

    International Nuclear Information System (INIS)

    Haskel, D.; Shechter, H.; Stern, E.A.; Newville, M.; Yacoby, Y.

    1993-01-01

    Sn impurities in Pb and Ag hosts have been investigated by Moessbauer effect and in Pb by x-ray-absorption fine-structure (XAFS) studies. The Sn atoms are dissolved up to at least 2 at. % in Pb and up to at least 8 at. % in Ag for the temperature ranges investigated. The concentration limit for Sn-Sn interactions is 1 at. % for Pb and 2 at. % for Ag as determined experimentally by lowering the Sn concentration until no appreciable change occurs in the Moessbauer effect. XAFS measurements verify that the Sn impurities in Pb are dissolved and predominantly at substitutional sites. For both hosts the temperature dependence of the spectral intensities of isolated Sn impurities below a temperature T 0 is as expected for vibrating about a lattice site. Above T 0 the Moessbauer spectral intensity exhibits a greatly increased rate of drop-off with temperature without appreciable broadening. This drop-off is too steep to be explained by ordinary anharmonic effects and can be explained by a liquidlike rapid hopping of the Sn, localized about a lattice site. Higher-entropy-density regions of radii somewhat more than an atomic spacing surround such impurities, and can act as nucleation sites for three-dimensional melting

  1. Studying superconducting Nb$_{3}$Sn wire

    CERN Multimedia

    AUTHOR|(CDS)2099575

    2015-01-01

    Studying superconducting Nb$_{3}$Sn wire. From the current experience from LHC and HL-LHC we know that the performance requirements for Nb$_{3}$Sn conductor for future circular collider are challenging and should exceed that of present state-of-the-art materials.

  2. Neutrino properties and supernova SN1987a

    International Nuclear Information System (INIS)

    Nussinov, S.

    1989-01-01

    The use of SN1987a to indicate how limits on neutrino properties can be deduced from the observed neutrino signals is shown. Bounds on possible deviations from relativity are briefly considered. The possible evidence for a half-millisecond pulsar in the SN remnant and on speculative attempts at finding the same periodicity in the neutrino signal are commented on. 37 refs

  3. Central {sup 112}Sn + {sup 58}Ni, {sup 124}Sn + {sup 64}Ni collisions in the Reverse Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Geraci, E.; Bruno, M.; D' Agostino, M.; Vannini, G. [Bologna Univ., Dipartimento di Fisica (Italy); Anzalone, A.; Baran, V.; Bonasera, A.; Cavallaro, S.; Colonna, M.; Di Toro, M.; Giustolisi, F.; Iacono-Manno, M.; La Guidara, E.; Lanzalone, G.; Porto, F.; Russotto, P.; Maiolino, C.; Sperduto, M.I. [Catania Univ., INFN-LNS and Dipartimento di Fisica e Astronomia (Italy); Alderighi, M.; Bartolucci, M.; Sechi, G. [INFN and Istituto di Fisica Cosmica, CNR, Milano (Italy); Auditore, L.; Trifiro, A.; Rimarchi, M. [Messina Univ., INFN and Dipartimento di Fisica (Italy); Berceanu, I.; Petrovici, M.; Simion, S. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Guazzoni, P.; Russo, S.; Manfredi, G.; Zetta, L. [Milano Univ., INFN and Dipartimento di Fisica (Italy); Blicharska, J.; Grzeszczuk, A.; Kowalski, S.; Paduszynski, T.; Zipper, W. [Silesia Univ., Institute of Physics, Katowice (Poland); Borderie, B.; Le Neindre, N.; Rivet, M.F. [Institut de Physique nucleaire, IN2P3-CNRS, 91 - Orsay (France); Bougault, B.R.; Steckmeyer, J.C. [Caen Univ., LPC, ENSI, 14 (France); Brzychczyk, J.; Majka, Z. [Jagellonian Univ., M.Smoluchowski Institute of Physics, Cracow (Poland); Cardella, G.; Filippo, E. de; Lanzano, G.; Li, S.; Lo Nigro, S.; Pagano, A.; Papa, M.; Pirrone, S.; Politi, G. [Catania Univ., INFN and Dipartimento di Fisica e Astronomia (Italy); Chbihi, A.; Wieleczko, J.P. [GANIL, CEA, IN2P3-CNRS, 14 - Caen (France); Cibor, J. [H. Niewodniczanski Institute of Nuclear Physics, Cracov (Poland); Guinet, D. [Institut de Physique nucleaire, IN2P3-CNRS, 69 - Lyon (France); Wu, H.; Xiao, Z. [Institute of Modern Physics Lanzhou (China); Piasecki, E. [Warsaw Univ., Institute of Experimental Physics (Poland); Rosato, E.; Vigilante, M. [Napoli Univ., INFN and Dipartimento di Fisica (Italy); Wilczynski, J. [Institute for Nuclear Studies, Otwock-Swierk (Poland)

    2003-07-01

    {sup 112}Sn + {sup 58}Ni and {sup 124}Sn + {sup 64}Ni reactions at 35 AMeV incident energy were studied using the 688 Si-CsI(Tl) telescopes of the forward part (1 {<=} {theta} {<=} 30 degrees) of CHIMERA multi-detector. The most central part of the total measured cross section was selected by means of a multidimensional analysis of the experimental observables. The characteristics of the source formed in the central collisions, as size, temperature and volume, were inspected. The detected isotopes of light fragments (3 {<=} Z {<=} 8) provided information on breakup temperatures of the emitting sources. The space-time structure of these sources was deduced from the two-fragment velocity correlation functions. Isotope yield ratios were used to extract the freeze-out unbound relative neutron and proton densities and the neutron to proton density of both studied reactions, indicating for a possible isospin distillation mechanism. (authors)

  4. Electrodeposition of nanostructured Sn-Zn coatings

    Science.gov (United States)

    Salhi, Y.; Cherrouf, S.; Cherkaoui, M.; Abdelouahdi, K.

    2016-03-01

    The electrodeposition of Sn-Zn coating at ambient temperature was investigated. The bath consists of metal salts SnCl2·2H2O and ZnSO4·7H2O and sodium citrate (NaC6H5Na3O7·2H2O) as complexing agent. To prevent precipitation, the pH is fixed at 5. Reducing tin and zinc through Sncit2- and ZnHcit- complex respectively is confirmed by the presence of two cathodic peaks on the voltammogram. The kinetic of tin (II) reduction process is limited by the SnCit2- dissociation. The SEM and TEM observations have showed that the coating consists of a uniform Sn-Zn layer composed of fine grains on which tin aggregates grow up. XRD revealed peaks corresponding to the hexagonal Zn phase and the tetragonal β-Sn phase.

  5. Laser spectroscopy of neutron deficient Sn isotopes

    CERN Multimedia

    We propose to study the ground state properties of neutron-deficient Sn isotopes towards the doubly-magic nucleus $^{100}$Sn. Nuclear spins, changes in the rms charge radii and electromagnetic moments of $^{101-121}$Sn will be measured by laser spectroscopy using the CRIS experimental beam line. These ground-state properties will help to clarify the evolution of nuclear structure properties approaching the $\\textit{N = Z =}$ 50 shell closures. The Sn isotopic chain is currently the frontier for the application of state-of-the-art ab-initio calculations. Our knowledge of the nuclear structure of the Sn isotopes will set a benchmark for the advances of many-body methods, and will provide an important test for modern descriptions of the nuclear force.

  6. Synthesis of Ce-doped SnO{sub 2} nanoparticles and their acetone gas sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Xiaoxue, E-mail: lianxiaoxues@163.com; Li, Yan; Tong, Xiaoqiang; Zou, Yunling; Liu, Xiulin; An, Dongmin; Wang, Qiong

    2017-06-15

    Highlights: • The Ce-doped SnO{sub 2} nanoparticles were fabricated via a simple hydrothermal method. • Ce ions were successfully doped into the SnO{sub 2} lattice, and 5 wt% SnO{sub 2}:Ce had a higher specific surface area. • The Ce-doped SnO{sub 2} nanoparticles exhibited the highest response values and a well selectivity to acetone. - Abstract: Hydrothermal method was generally used to synthesis nanoparticles, which was used to fabricate pure and Ce-doped (3 wt%, 5 wt%, 7 wt%) SnO{sub 2} nanoparticles in this experiment. The as-prepared products were characterized by X-ray diffraction (XRD), energy dispersive spectrum (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET). The results clearly indicated that the nanoparticles were composed of SnO{sub 2} nanoparticles and Ce ions were successfully doped into the SnO{sub 2} lattice, and 5 wt% SnO{sub 2}:Ce has a higher specific surface area (173.53 m{sup 2}/g). Importantly, SnO{sub 2}:Ce sensor had obviously improved performance compared to pure SnO{sub 2} and exhibited the highest response values (50.5 for 50 ppm) and a well selectivity to acetone at 270 °C. It could detect acetone gas in a wide concentration range with very high response, good long-term stability and repeatability of response. The possible sensing mechanism was discussed in this paper.

  7. Reduction of secondary phases in Cu{sub 2}SnSe{sub 3} absorbers for solar cell application

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zeguo, E-mail: tangzg@fc.ritsumei.ac.jp [Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Shiga (Japan); Nukui, Yuki; Kosaka, Kiichi; Ashida, Naoki; Uegaki, Hikaru; Minemoto, Takashi [College of Science and Engineering, Ritsumeikan University, Shiga (Japan)

    2014-09-01

    Highlights: • Cu{sub 2}SnSe{sub 3} thin films for absorber of solar cell are fabricated by selenization of Cu–Sn precursors. • Secondary phase of Cu{sub 2–x}Se can be suppressed via using Se and SnSe mixture powders as Se source. • Selective etching of secondary phase of Cu{sub 2–x}Se is realized by potassium cyanide solution. • Cu{sub 2–x}Se rather than SnSe makes major contribution to the high carrier concentration of CTSe films. - Abstract: The creation of secondary phases, such as Cu{sub 2−x}Se and SnSe, and their influence on electrical properties of Cu{sub 2}SnSe{sub 3} (CTSe) thin films fabricated by selenization of Cu–Sn metal precursors are investigated. The Cu{sub 2−x}Se content in CTSe films is estimated via deconvolution of grazing incidence X-ray diffraction (GIXRD) patterns, and the results suggest that the Cu{sub 2−x}Se content increases with the increasing Cu/Sn ratio in metal precursors. We also found that using Se and SnSe mixture powders as Se source is an effective approach to suppress the creation of Cu{sub 2−x}Se secondary phase. Meanwhile, selective etching of Cu{sub 2−x}Se is realized by potassium cyanide (KCN) solution. Hall measurement results reveal that the secondary phase of Cu{sub 2−x}Se rather than SnSe makes major contribution to the high carrier concentration (larger than 10{sup 18} cm{sup −3}) of CTSe films. The approach to further decrease the carrier concentration in CTSe films is discussed.

  8. HET0016, a selective inhibitor of 20-HETE synthesis, decreases pro-angiogenic factors and inhibits growth of triple negative breast cancer in mice.

    Directory of Open Access Journals (Sweden)

    Thaiz Ferraz Borin

    Full Text Available A selective inhibitor of 20-HETE synthesis, HET0016, has been reported to inhibit angiogenesis. 20-HETE has been known as a second mitogenic messenger of angiogenesis inducing growth factors. HET0016 effects were analyzed on MDA-MB-231 derived breast cancer in mouse and in vitro cell line. MDA-MB-231 tumor cells were implanted in animals' right flank and randomly assigned to early (1 and 2, starting treatments on day 0, or delayed groups (3 and 4 on day 8 after implantation of tumor. Animals received HET0016 (10 mg/kg treatment via intraperitoneal injection for 5 days/week for either 3 or 4 weeks. Control group received vehicle treatment. Tumor sizes were measured on days 7, 14, 21, and 28 and the animals were euthanized on day 22 and 29. Proteins were extracted from the whole tumor and from cells treated with 10 µM HET0016 for 4 and 24 hrs. Protein array kits of 20 different cytokines/factors were used. ELISA was performed to observe the HIF-1α and MMP-2 protein expression. Other markers were confirmed by IHC. HET0016 significantly inhibited tumor growth in all treatment groups at all-time points compared to control (p<0.05. Tumor growth was completely inhibited on three of ten animals on early treatment group. Treatment groups showed significantly lower expression of pro-angiogenic factors compared to control at 21 days; however, there was no significant difference in HIF-1α expression after treatments. Similar results were found in vitro at 24 hrs of HET0016 treatment. After 28 days, significant increase of angiogenin, angiopoietin-1/2, EGF-R and IGF-1 pro-angiogenic factors were found (p<0.05 compared to control, as well as an higher intensity of all factors were found when compared to that of 21 day's data, suggesting a treatment resistance. HET0016 inhibited tumor growth by reducing expression of different set of pro-angiogenic factors; however, a resistance to treatment seemed to happen after 21 days.

  9. Do tumor size or patient age influence the accuracy of sentinel lymph node (Sn) detection in breast cancer?

    International Nuclear Information System (INIS)

    Cortes, M.; Fernandez, A.; Benito, E.; Azpeitia, D.; Ricart, Y.; Escobedo, A.; Martin-Comin, J.

    2002-01-01

    Full text: The aim was to analyze the influence of the age of the patient and tumor size on the accuracy to identify SN in patients with breast cancer. The whole population are 250 patients with breast cancer. In 236 data on size and age were available. Mean age was 53.6 years, range 28-87 years. Patients were classified 1) depending an age: 40 60 years: 73 p and 2) depending on tumor size (mm): 30: 46 p. Examination protocol: All patients received a peritumoral injection of 111 MBq (3mCi) of 99mTc-HSA-nanocolloid in 1 - 3 ml. 2 h later 300 seconds anterior and lateral thoracic scans were obtained. A 57-Co flood phantom was positioned back to the patient to outline the anatomical contour and help to localize SN. SN was marked on the skin with permanent ink. Intraoperative SN localization was performed using a gamma probe. Histopathologic analysis of SN was done with haematoxylin/eosin, immunohistochemistry and PCR. Histopathology of the SN was compared to the histopathology of all the other lymph nodes drawn out by the surgeon. SN were identified by lymphoscintigraphy in 227 cases of 250 (91 %). 221 of them (97 %) were localized in axyla. In 210 of 221 SN could be localized and drawn out at surgery. The no detection and false negative rate were much higher in patients aged > 60 (29 and 33 %) and in tumors > 30 mm (32 and 19 %) than in patients 60 y and tumors > 30 mm (46 %) and the highest false negative rate appears in patients >60 and tumors > 30 mm (33 %) 1) No FN were found in patients with tumor size <10 mm. 2) No FN were found in patients aged under 40 years. 3) FN rate seems to be higher in older patients. 4) The age of patients and the size of tumor seem to influence an the SN detection rates. (author)

  10. The improvement of gas-sensing properties of SnO2/zeolite-assembled composite

    Science.gov (United States)

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

    2018-05-01

    SnO2-impregnated zeolite composites were used as gas-sensing materials to improve the sensitivity and selectivity of the metal oxide-based resistive-type gas sensors. Nanocrystalline MFI type zeolite (ZSM-5) was prepared by hydrothermal synthesis. Highly dispersive SnO2 nanoparticles were then successfully assembled on the surface of the ZSM-5 nanoparticles by using the impregnation methods. The SnO2 nanoparticles are nearly spherical with the particle size of 10 nm. An enhanced formaldehyde sensing of as-synthesized SnO2-ZSM-5-based sensor was observed whereas a suppression on the sensor response to other volatile organic vapors (VOCs) such as acetone, ethanol, and methanol was noticed. The possible reasons for this contrary observation were proposed to be related to the amount of the produced water vapor during the sensing reactions assisted by the ZSM-5 nanoparticles. This provides a possible new strategy to improve the selectivity of the gas sensors. The effect of the humidity on the sensor response to formaldehyde was investigated and it was found the higher humidity would decrease the sensor response. A coating layer of the ZSM-5 nanoparticles on top of the SnO2-ZSM-5-sensing film was thus applied to further improve the sensitivity and selectivity of the sensor through the strong adsorption ability to polar gases and the "filtering effect" by the pores of ZSM-5.

  11. Highly sensitive SnO2 sensor via reactive laser-induced transfer

    Science.gov (United States)

    Palla Papavlu, Alexandra; Mattle, Thomas; Temmel, Sandra; Lehmann, Ulrike; Hintennach, Andreas; Grisel, Alain; Wokaun, Alexander; Lippert, Thomas

    2016-04-01

    Gas sensors based on tin oxide (SnO2) and palladium doped SnO2 (Pd:SnO2) active materials are fabricated by a laser printing method, i.e. reactive laser-induced forward transfer (rLIFT). Thin films from tin based metal-complex precursors are prepared by spin coating and then laser transferred with high resolution onto sensor structures. The devices fabricated by rLIFT exhibit low ppm sensitivity towards ethanol and methane as well as good stability with respect to air, moisture, and time. Promising results are obtained by applying rLIFT to transfer metal-complex precursors onto uncoated commercial gas sensors. We could show that rLIFT onto commercial sensors is possible if the sensor structures are reinforced prior to printing. The rLIFT fabricated sensors show up to 4 times higher sensitivities then the commercial sensors (with inkjet printed SnO2). In addition, the selectivity towards CH4 of the Pd:SnO2 sensors is significantly enhanced compared to the pure SnO2 sensors. Our results indicate that the reactive laser transfer technique applied here represents an important technical step for the realization of improved gas detection systems with wide-ranging applications in environmental and health monitoring control.

  12. V-groove SnO2 nanowire sensors: fabrication and Pt-nanoparticle decoration

    International Nuclear Information System (INIS)

    Sun, Gun-Joo; Choi, Sun-Woo; Jung, Sung-Hyun; Katoch, Akash; Kim, Sang Sub

    2013-01-01

    Networked SnO 2 nanowire sensors were achieved using the selective growth of SnO 2 nanowires and their tangling ability, particularly on on-chip V-groove structures, in an effort to overcome the disadvantages imposed on the conventional trench-structured SnO 2 nanowire sensors. The sensing performance of the V-groove-structured SnO 2 nanowire sensors was highly dependent on the geometrical dimension of the groove, being superior to those of their conventional trench-structured counterparts. Pt nanoparticles were decorated on the surface of the networked SnO 2 nanowires via γ-ray radiolysis to enhance the sensing performances of the V-groove sensors whose V-groove widths had been optimized. The V-groove-structured Pt-nanoparticle-decorated SnO 2 nanowire sensors exhibited outstanding and reliable sensing capabilities towards toluene and nitrogen dioxide gases, indicating their potential for use as a platform for chemical gas sensors. (paper)

  13. Solidification of Al-Sn-Cu Based Immiscible Alloys under Intense Shearing

    Science.gov (United States)

    Kotadia, H. R.; Doernberg, E.; Patel, J. B.; Fan, Z.; Schmid-Fetzer, R.

    2009-09-01

    The growing importance of Al-Sn based alloys as materials for engineering applications necessitates the development of uniform microstructures with improved performance. Guided by the recently thermodynamically assessed Al-Sn-Cu system, two model immiscible alloys, Al-45Sn-10Cu and Al-20Sn-10Cu, were selected to investigate the effects of intensive melt shearing provided by the novel melt conditioning by advanced shear technology (MCAST) unit on the uniform dispersion of the soft Sn phase in a hard Al matrix. Our experimental results have confirmed that intensive melt shearing is an effective way to achieve fine and uniform dispersion of the soft phase without macro-demixing, and that such dispersed microstructure can be further refined in alloys with precipitation of the primary Al phase prior to the demixing reaction. In addition, it was found that melt shearing at 200 rpm and 60 seconds will be adequate to produce fine and uniform dispersion of the Sn phase, and that higher shearing speed and prolonged shearing time can only achieve minor further refinement.

  14. Ethanol electrooxidation on novel carbon supported Pt/SnO{sub x}/C catalysts with varied Pt:Sn ratio

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, L. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian (China); Colmenares, L.; Jusys, Z. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany); Sun, G.Q. [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian (China)], E-mail: gqsun@dicp.ac.cn; Behm, R.J. [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany)], E-mail: juergen.behm@uni-ulm.de

    2007-12-01

    Novel carbon supported Pt/SnO{sub x}/C catalysts with Pt:Sn atomic ratios of 5:5, 6:4, 7:3 and 8:2 were prepared by a modified polyol method and characterized with respect to their structural properties (X-ray diffraction (XRD) and transmission electron microscopy (TEM)), chemical composition (XPS), their electrochemical properties (base voltammetry, CO{sub ad} stripping) and their electrocatalytic activity and selectivity for ethanol oxidation (ethanol oxidation reaction (EOR)). The data show that the Pt/SnO{sub x}/C catalysts are composed of Pt and tin oxide nanoparticles with an average Pt particle diameter of about 2 nm. The steady-state activity of the Pt/SnO{sub x}/C catalysts towards the EOR decreases with tin content at room temperature, but increases at 80 deg. C. On all Pt/SnO{sub x}/C catalysts, acetic acid and acetaldehyde represent dominant products, CO{sub 2} formation contributes 1-3% for both potentiostatic and potentiodynamic reaction conditions. With increasing potential, the acetaldehyde yield decreases and the acetic acid yield increases. The apparent activation energies of the EOR increase with tin content (19-29 kJ mol{sup -1}), but are lower than on Pt/C (32 kJ mol{sup -1}). The somewhat better performance of the Pt/SnO{sub x}/C catalysts compared to alloyed PtSn{sub x}/C catalysts is attributed to the presence of both sufficiently large Pt ensembles for ethanol dehydrogenation and C-C bond splitting and of tin oxide for OH generation. Fuel cell measurements performed for comparison largely confirm the results obtained in model studies.

  15. Isotope correlations as a probe for freeze-out characterization: central {sup 124}Sn+{sup 64}Ni, {sup 112}Sn+{sup 58}Ni collisions

    Energy Technology Data Exchange (ETDEWEB)

    Geraci, E.; Alderighi, M.; Anzalone, A.; Auditore, L.; Baran, V.; Bartolucci, M.; Berceanu, I.; Blicharska, J.; Bonasera, A.; Borderie, B.; Bougault, R.; Bruno, M.; Brzychczyk, J.; Cardella, G.; Cavallaro, S.; Chbihi, A.; Cibor, J.; Colonna, M.; D' Agostino, M.; De Filippo, E.; Di Toro, M.; Giustolisi, F.; Grzeszczuk, A.; Guazzoni, P.; Guinet, D.; Iacono-Manno, M.; Kowalski, S.; La Guidara, E.; Lanzalone, G.; Lanzano, G.; Le Neindre, N.; Li, S.; Lo Nigro, S.; Maiolino, C.; Majka, Z.; Manfredi, G.; Paduszynski, T.; Pagano, A.; Papa, M.; Petrovici, M.; Piasecki, E.; Pirrone, S.; Politi, G.; Pop, A.; Porto, F.; Rivet, M.F.; Rosato, E.; Russo, S.; Russotto, P.; Sechi, G.; Simion, V.; Sperduto, M.L.; Steckmeyer, J.C.; Trifiro, A.; Trimarchi, M.; Vannini, G.; Vigilante, M.; Wieleczko, J.P.; Wilczynski, J.; Wu, H.; Xiao, Z.; Zetta, L.; Zipper, W

    2004-04-05

    {sup 124}Sn+{sup 64}Ni and {sup 112}Sn+{sup 58}Ni reactions at 35 AMeV incident energy were studied with the forward part of CHIMERA multi-detector. The most central collisions were selected by means of a multidimensional analysis. The characteristics of the source formed in the central collisions, as size, temperature and volume, were inspected. The measured isotopes of light fragments (3 {<=} Z {<=} 8) were used to examine isotope yield ratios that provide information on the free neutron to proton densities.

  16. Controlled Synthesis of Heterostructured SnO2-CuO Composite Hollow Microspheres as Efficient Cu-Based Catalysts for the Rochow Reaction

    Directory of Open Access Journals (Sweden)

    Hezhi Liu

    2018-04-01

    Full Text Available In this work, we report the design and synthesis of a series of heterostructured SnO2-CuO hollow microspherical catalysts (H-SnO2(x-CuO, x is the weight ratio of Sn/Cu for the Rochow reaction. The microspherical catalysts with nanosheets and nanoparticles as building blocks were prepared by a facile one-pot hydrothermal method coupled with calcination. When tested for the Rochow reaction, the prepared H-SnO2(0.2-CuO composite exhibited higher dimethyldichlorosilane selectivity (88.2% and Si conversion (36.7% than the solid CuO, hollow CuO and other H-SnO2(x-CuO microspherical samples, because in the former there is a stronger synergistic interaction between CuO and SnO2.

  17. Three NiAs-Ni 2In Type Structures in the Mn-Sn System

    Science.gov (United States)

    Elding-Pontén, Margareta; Stenberg, Lars; Larsson, Ann-Kristin; Lidin, Sven; Ståhl, Kenny

    1997-03-01

    TheB8-type structure field of the Mn-Sn system has been investigated. Two high temperature phases (HTP1 and HTP2) and one low temperature phase (Mn3Sn2) were found. They all crystallize with the NiAs structure type with part of the trigonal bipyramidal interstices filled by manganese atoms in an ordered manner. The ordering as well as the manganese content is different for the three phases, giving rise to three different orthorhombic superstructures. Mn3Sn2seems to have the lowest manganese content, since the corresponding basal unit cell is smaller than for HTP1-2. Structural models of the phases are based on selected area electron diffraction, X-ray powder diffraction, and preliminary single crystal X-ray measurements. The ideal cell parameters found are (a=7ahex,b=3ahex,c=chex), (a=5ahex,b=3ahex,c=chex), and (a=2ahex,b=3ahex,c=chex) for HTP1, HTP2, and Mn3Sn2, respectively. The crystal structure of Mn3Sn2has been refined by means of the Rietveld method from X-ray powder diffraction data. Mn3Sn2is orthorhombic,Pnma,a=7.5547(2),b=5.4994(2),c=8.5842(2) Å,Z=4. (Pbnmin the setting above.) The compound is isostructural with Ni3Sn2andγ‧-Co3Sn2(H. Fjellvåg and A. Kjekshus,Acta Chem. Scand.A40, 23-30 (1986)). FinalRp=8.97%,Rwp=11.44%, GOF=2.86, andRBragg=4.11% using 43 parameters and 5701 observations and 330 Bragg reflections.

  18. Spinal Muscular Atrophy: From Defective Chaperoning of snRNP Assembly to Neuromuscular Dysfunction

    Directory of Open Access Journals (Sweden)

    Maia Lanfranco

    2017-06-01

    Full Text Available Spinal Muscular Atrophy (SMA is a neuromuscular disorder that results from decreased levels of the survival motor neuron (SMN protein. SMN is part of a multiprotein complex that also includes Gemins 2–8 and Unrip. The SMN-Gemins complex cooperates with the protein arginine methyltransferase 5 (PRMT5 complex, whose constituents include WD45, PRMT5 and pICln. Both complexes function as molecular chaperones, interacting with and assisting in the assembly of an Sm protein core onto small nuclear RNAs (snRNAs to generate small nuclear ribonucleoproteins (snRNPs, which are the operating components of the spliceosome. Molecular and structural studies have refined our knowledge of the key events taking place within the crowded environment of cells and the numerous precautions undertaken to ensure the faithful assembly of snRNPs. Nonetheless, it remains unclear whether a loss of chaperoning in snRNP assembly, considered as a “housekeeping” activity, is responsible for the selective neuromuscular phenotype in SMA. This review thus shines light on in vivo studies that point toward disturbances in snRNP assembly and the consequential transcriptome abnormalities as the primary drivers of the progressive neuromuscular degeneration underpinning the disease. Disruption of U1 snRNP or snRNP assembly factors other than SMN induces phenotypes that mirror aspects of SMN deficiency, and splicing defects, described in numerous SMA models, can lead to a DNA damage and stress response that compromises the survival of the motor system. Restoring the correct chaperoning of snRNP assembly is therefore predicted to enhance the benefit of SMA therapeutic modalities based on augmenting SMN expression.

  19. Spectral and ion emission features of laser-produced Sn and SnO2 plasmas

    Science.gov (United States)

    Hui, Lan; Xin-Bing, Wang; Du-Luo, Zuo

    2016-03-01

    We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and SnO2 plasmas under identical experimental conditions. Planar slabs of pure metal Sn and ceramic SnO2 are irradiated with 1.06 μm, 8 ns Nd:YAG laser pulses. Fast photography employing an intensified charge coupled device (ICCD), optical emission spectroscopy (OES), and optical time of flight emission spectroscopy are used as diagnostic tools. Our results show that the Sn plasma provides a higher extreme ultraviolet (EUV) conversion efficiency (CE) than the SnO2 plasma. However, the kinetic energies of Sn ions are relatively low compared with those of SnO2. OES studies show that the Sn plasma parameters (electron temperature and density) are lower compared to those of the SnO2 plasma. Furthermore, we also give the effects of the vacuum degree and the laser pulse energy on the plasma parameters. Project supported by the National Natural Science Foundation of China (Grant No. 11304235) and the Director Fund of WNLO, China.

  20. Sn-In-Ag phase equilibria and Sn-In-(Ag)/Ag interfacial reactions

    International Nuclear Information System (INIS)

    Chen Sinnwen; Lee Wanyu; Hsu Chiaming; Yang Chingfeng; Hsu Hsinyun; Wu Hsinjay

    2011-01-01

    Research highlights: → Thermodynamic models of Sn-In and Sn-In-Ag are developed using the CALPHAD approach. → Reaction layer in the Sn-In-(Ag)/Ag couples at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. → Reactions in the Sn-20 wt%In-2.8 wt%Ag/Ag couples are faster than those in the Sn-20 wt%In/Ag couples. - Abstract: Experimental verifications of the Sn-In and Sn-In-Ag phase equilibria have been conducted. The experimental measurements of phase equilibria and thermodynamic properties are used for thermodynamic modeling by the CALPHAD approach. The calculated results are in good agreement with experimental results. Interfacial reactions in the Sn-In-(Ag)/Ag couples have been examined. Both Ag 2 In and AgIn 2 phases are formed in the Sn-51.0 wt%In/Ag couples reacted at 100 and 150 deg. C, and only the Ag 2 In phase is formed when reacted at 25, 50 and 75 deg. C. Due to the different growth rates of different reaction phases, the reaction layer at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. In the Sn-20.0 wt%In/Ag couples, the ζ phase is formed at 250 deg. C and ζ/AgIn 2 phases are formed at 125 deg. C. Compared with the Sn-20 wt%In/Ag couples, faster interfacial reactions are observed in the Sn-20.0 wt%In-2.8 wt%Ag/Ag couples, and minor Ag addition to Sn-20 wt%In solder increases the growth rates of the reaction phases.

  1. Growth of highly textured SnS on mica using an SnSe buffer layer

    International Nuclear Information System (INIS)

    Wang, S.F.; Fong, W.K.; Wang, W.; Surya, C.

    2014-01-01

    We report the growth of SnS thin films on mica substrates by molecular beam epitaxy. Excellent 2D layered structure and strong (001) texture were observed with a record low rocking curve full width at half maximum of ∼ 0.101° for the SnS(004) diffraction. An interface model is used to investigate the nucleation of SnS on mica which indicates the co-existence of six pairs of lateral growth orientations and is in excellent agreement with the experimental Φ-scan measurements indicating 12 peaks separated by 30° from each other. To control the lateral growth of the SnS epilayers we investigate the utilization of a thin SnSe buffer layer deposited on the mica substrate prior to the growth of the SnS thin film. The excellent lattice match between SnSe and mica enhances the alignment of the nucleation of SnS and suppresses the minor lateral orientations along the mica[110] direction and its orthogonal axis. Detailed low-frequency noise measurement was performed to characterize the trap density in the films and our results clearly demonstrate substantial reduction in the density of the localized states in the SnS epilayer with the use of an SnSe buffer layer. - Highlights: • A record low rocking curve FWHM for deposited SnS on mica • Investigation of the nucleation of SnS on mica using the interface model • Investigation of nucleation mechanism by phi-scan measurement • Grain boundary formation from crystallites of various nucleation orientations • Suppression of nucleation orientations using an SnSe buffer layer

  2. Realization of ppm-level CO detection with exceptionally high sensitivity using reduced graphene oxide-loaded SnO2 nanofibers with simultaneous Au functionalization.

    Science.gov (United States)

    Kim, Jae-Hun; Katoch, Akash; Kim, Hyoun Woo; Kim, Sang Sub

    2016-03-07

    We have realized the highly sensitive, selective ppm-level carbon monoxide (CO) detection based on graphene oxide (RGO) nanosheets-loaded SnO2 nanofibers with simultaneous Au functionalization. The interplay between RGO/Au and SnO2 in terms of transfer of charge carriers and modulation of potential barriers is responsible for the exceptionally high CO detectability.

  3. Nuclear-spectroscopic studies in the 132Sn region

    International Nuclear Information System (INIS)

    Arndt, Oliver

    2007-10-01

    In this work investigations on r-process nuclides around the N = 82 shell closure are done. The so far unknown half-lives and P n -values of 137-139 Sb and 139 Te and their impact to r-process theory are given. Further the results of Shergur et. al. of neutron rich tin ( 137,138 Sn) are verified and in some points improved. New data on γ-decay spectroscopy for 136 Sn from single spectra is published. To improve beam quality and solve long known problems on ISOL-facilities with isobaric contamination, new techniques are discussed. A special focus is on molecular sidebands, which is first time adapted to a target/ion source unit in a mass separation facility. It was possible to create a strong SnS + sideband and in this way to reduce isobaric background with good beam intensities. On the other hand, a target with temperature controlled transfer line was build and its characteristics are discussed. To improve selectivity of a given experiment on neutron rich nuclei a new detector system for nγ-coincidences was developed. Due to a special electronically setup of the new system it was possible to downsize the coincidence window compared to earlier attempts. (orig.)

  4. RCI Simulation for EUV spectra from Sn ions

    International Nuclear Information System (INIS)

    Kagawa, T; Tanuma, H; Ohashi, H; Nishihara, K

    2007-01-01

    Using the relativistic-configuration-interaction atomic structure code, RCI simulations for EUV spectra from Sn 10+ , Sn 11+ and Sn 12+ ions are carried out, where it is assumed that each ion is embedded in a LTE plasma with the electron temperature of 30 eV. To make clear assignment of the measured spectra, the value of the excitation energy limit, which is introduced to limit the number of excited states in the simulation, is changed to see the excitation-energy-limit dependence of the spectral shape. The simulated spectra are obtained as a superposition of line intensities due to all possible transitions between two states whose excitation energy from the ground state is lower than the excitation energy limit assumed. The RCI simulated spectra are compared to the spectra measured with the chargeexchange- collision experiment in which a rare gas such as Xe or He as a target is bombarded by a charge-selected tin ion. Applicability of the LTE model to a decay model in the charge exchange collision experiment is also discussed

  5. Ethanol sensing properties and dominant sensing mechanism of NiO-decorated SnO2 nanorod sensors

    Science.gov (United States)

    Sun, Gun-Joo; Lee, Jae Kyung; Lee, Wan In; Dwivedi, Ram Prakash; Lee, Chongmu; Ko, Taegyung

    2017-05-01

    NiO-decorated SnO2 nanorods were synthesized by the thermal evaporation of Sn powders followed by the solvothermal deposition of NiO. A multi-networked p- n heterostructured nanorod sensor was fabricated by dropping the p-NiO-decorated n-SnO2 nanorods onto the interdigited electrode pattern and then annealing. The multi-networked p- n heterostructured nanorod sensor exhibited enhanced response to ethanol compared with the pristine SnO2 nanorod and NiO nanoparticle sensors. The former also exhibited a shorter sensing time for ethanol. Both sensors exhibited selectivity for ethanol over other volatile organic compounds (VOCs) such as HCHO, methanol, benzene and toluene and the decorated sensor exhibited superior selectivity to the other two sensors. In addition, the dominant sensing mechanism is discussed in detail by comparing the sensing properties and current-voltage characteristics of a p-NiO/ n-SnO2 heterostructured nanorod sensor with those of a pristine SnO2 nanorod sensor and a pristine NiO nanoparticle sensor. Of the two competing electronic mechanisms: a potential barrier-controlled carrier transport mechanism at a NiO-SnO2 p- n junction and a surface-depletio n-controlled carrier transport mechanism, the former has some contribution to the enhanced gas sensing performance of the p- n heterostructured nanorod sensor, however, its contribution is not as significant as that of the latter. [Figure not available: see fulltext.

  6. Sensitivity of PbSnTe:In films to the radiation of free electron laser

    Science.gov (United States)

    Akimov, A. N.; Epov, V. S.; Klimov, A. E.; Kubarev, V. V.; Paschin, N. S.

    2018-01-01

    The analysis of experimental data on the observation of photoresponse in narrow gap semiconductor Pb1-x Sn x Te:In films grown by the method of molecular beam epitaxy, exposing samples to the powerful radiation of the Novosibirsk free electron laser (wavelength range of about 70-240 μm) under different measurement conditions, is presented in the paper. Both the positive and negative photoconductivities were detected. In a magnetic field, the resonance-type photoconductivity was observed. The results are discussed within the framework of the model taking into account the existence of different capture levels in PbSnTe.

  7. Sensitization of Perovskite Strontium Stannate SrSnO3 towards Visible-Light Absorption by Doping

    Directory of Open Access Journals (Sweden)

    Hungru Chen

    2014-01-01

    Full Text Available Perovskite strontium stannate SrSnO3 is a promising photocatalyst. However, its band gap is too large for efficient solar energy conversion. In order to sensitize SrSnO3 toward visible-light activities, the effects of doping with various selected cations and anions are investigated by using hybrid density functional calculations. Results show that doping can result in dopant level to conduction band transitions which lie lower in energy compared to the original band gap transition. Therefore, it is expected that doping SrSnO3 can induce visible-light absorption.

  8. Nuclear-spectroscopic studies in the {sup 132}Sn region; Kernspektroskopische Untersuchungen in der {sup 132}Sn-Region

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, Oliver

    2007-10-15

    In this work investigations on r-process nuclides around the N = 82 shell closure are done. The so far unknown half-lives and P{sub n}-values of {sup 137-139}Sb and {sup 139}Te and their impact to r-process theory are given. Further the results of Shergur et. al. of neutron rich tin ({sup 137,138}Sn) are verified and in some points improved. New data on {gamma}-decay spectroscopy for {sup 136}Sn from single spectra is published. To improve beam quality and solve long known problems on ISOL-facilities with isobaric contamination, new techniques are discussed. A special focus is on molecular sidebands, which is first time adapted to a target/ion source unit in a mass separation facility. It was possible to create a strong SnS{sup +} sideband and in this way to reduce isobaric background with good beam intensities. On the other hand, a target with temperature controlled transfer line was build and its characteristics are discussed. To improve selectivity of a given experiment on neutron rich nuclei a new detector system for n{gamma}-coincidences was developed. Due to a special electronically setup of the new system it was possible to downsize the coincidence window compared to earlier attempts. (orig.)

  9. Ethanol electrooxidation on Pt-Sn and Pt-Sn-W bulk alloys

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, D.M. dos; Hahn, F.; Leger, J.M.; Kokoh, K.B. [Universite de Poitiers, Poitiers Cedex (France). Centre National de la Recherche Scientifique (CNRS). Equipe Electrocatalyse; Tremiliosi-Filho, G. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica

    2008-07-01

    Ethanol oxidation has been studied on Pt-Sn and Pt-Sn-W electrodes prepared in an arc-melting furnace. Different electrochemical techniques like cyclic voltammetry and chronoamperometry were used to evaluate the catalytic activity of these materials. The electro-oxidation process was also investigated by in situ infrared reflectance spectroscopy in order to determine adsorbed intermediates and reaction products. Experimental results indicated that Pt-Sn and Pt-Sn-W alloys are able to oxidize ethanol mainly to acetaldehyde and acetic acid. Adsorbed CO was also detected, demonstrating the viability of splitting the C-C bond in the ethanol molecule during the oxidation process. The adsorbed CO was further oxidized to CO{sub 2}.This reaction product was clearly detected by SNIFTIRS. Pt-Sn-W catalyst showed a better electrochemical performance than Pt-Sn that, in it turn, is better than Pt-alone. (author)

  10. Electrical and optical properties of SnEuTe and SnSrTe films

    Science.gov (United States)

    Ishida, Akihiro; Tsuchiya, Takuro; Yamada, Tomohiro; Cao, Daoshe; Takaoka, Sadao; Rahim, Mohamed; Felder, Ferdinand; Zogg, Hans

    2010-06-01

    The SnTe, Sn1-xEuxTe and Sn1-xSrxTe (x<0.06) films were prepared by hot wall epitaxy. The ternary alloy films prepared in cation rich condition had hole concentration around 1×1019 cm-3 with high mobility exceeding 2000 cm2/V s at room temperature. Optical transmission spectra were also measured in the temperature range from 100 to 400 K and compared with theoretical calculations. Optical transmission spectra of the SnTe were simulated successfully assuming bumped band edge structures. A band inversion model was proposed for the Sn1-xEuxTe and Sn1-xSrxTe systems, and the optical transmission spectra were also simulated successfully assuming the band inversion model.

  11. Different underlying mechanisms for face emotion and gender processing during feature-selective attention: Evidence from event-related potential studies.

    Science.gov (United States)

    Wang, Hailing; Ip, Chengteng; Fu, Shimin; Sun, Pei

    2017-05-01

    Face recognition theories suggest that our brains process invariant (e.g., gender) and changeable (e.g., emotion) facial dimensions separately. To investigate whether these two dimensions are processed in different time courses, we analyzed the selection negativity (SN, an event-related potential component reflecting attentional modulation) elicited by face gender and emotion during a feature selective attention task. Participants were instructed to attend to a combination of face emotion and gender attributes in Experiment 1 (bi-dimensional task) and to either face emotion or gender in Experiment 2 (uni-dimensional task). The results revealed that face emotion did not elicit a substantial SN, whereas face gender consistently generated a substantial SN in both experiments. These results suggest that face gender is more sensitive to feature-selective attention and that face emotion is encoded relatively automatically on SN, implying the existence of different underlying processing mechanisms for invariant and changeable facial dimensions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Insights from event-related potentials into the temporal and hierarchical organization of the ventral and dorsal streams of the visual system in selective attention.

    Science.gov (United States)

    Martín-Loeches, M; Hinojosa, J A; Rubia, F J

    1999-11-01

    The temporal and hierarchical relationships between the dorsal and the ventral streams in selective attention are known only in relation to the use of spatial location as the attentional cue mediated by the dorsal stream. To improve this state of affairs, event-related brain potentials were recorded while subjects attended simultaneously to motion direction (mediated by the dorsal stream) and to a property mediated by the ventral stream (color or shape). At about the same time, a selection positivity (SP) started for attention mediated by both streams. However, the SP for color and shape peaked about 60 ms later than motion SP. Subsequently, a selection negativity (SN) followed by a late positive component (LPC) were found simultaneously for attention mediated by both streams. A hierarchical relationship between the two streams was not observed, but neither SN nor LPC for one property was completely insensitive to the values of the other property.

  13. Lithium insertion mechanism in SnS2

    International Nuclear Information System (INIS)

    Lefebvre-Devos, I.; Olivier-Fourcade, J.; Jumas, J.C.; Lavela, P.

    2000-01-01

    We study lithium insertion in SnS 2 by means of 119 Sn Moessbauer spectroscopy, x-ray absorption spectroscopy at Sn L I,III , and S K edges, and theoretical electronic structures (calculated in the density-functional theory framework). An insertion mechanism is derived according to the Li amount. It shows the influence of the SnS 2 -layered structure on the Sn reduction, particularly the possibility of an intermediate oxidation state between Sn IV and Sn II , which is not observed during Li insertion in three-dimensional sulfides

  14. Vertically aligned nitrogen doped (Sn,Nb)O_2 nanotubes – Robust photoanodes for hydrogen generation by photoelectrochemical water splitting

    International Nuclear Information System (INIS)

    Patel, Prasad Prakash; Hanumantha, Prashanth Jampani; Velikokhatnyi, Oleg I.; Datta, Moni Kanchan; Gattu, Bharat; Poston, James A.; Manivannan, Ayyakkannu; Kumta, Prashant N.

    2016-01-01

    Graphical abstract: - Highlights: • Nb and N co-doping provides excellent optoelectronic properties for SnO_2 NTs. • The optoelectronic properties of doped SnO_2 are studied by first principles study. • (Sn_0_._9_5Nb_0_._0_5)O_2:N-600 NTs exhibits superior ABPE (4.1%) to date. • Excellent photoelectrochemical stability of (Sn_0_._9_5Nb_0_._0_5)O_2:N-600 NTs. - Abstract: Hydrogen generation from photoelectrochemical (PEC) water splitting is on the forefront of clean energy generation landscape. The efficiency of PEC system is dependent on the engineering of semiconductors with tailored narrow band gap coupled with superior photoelectrochemical activity and desired stability vital for the commercialization of PEC water splitting cells. We report herein the study of vertically aligned Nb and N doped SnO_2 nanotubes (NTs), i.e., (Sn_0_._9_5Nb_0_._0_5)O_2:N NTs for PEC water splitting. (Sn_0_._9_5Nb_0_._0_5)O_2 NTs was selected for co-doping with nitrogen by systematic analysis of applied bias photon-to-current efficiency of various Nb doped SnO_2 (x = 0–0.1) compositions. Consequently, excellent photoelectrochemical stability and the highest efficiency of 4.1% is obtained for (Sn_0_._9_5Nb_0_._0_5)O_2:N-600 NTs never observed for other known TiO_2, ZnO, and Fe_2O_3 systems to date. Additionally, theoretical first principles study provides understanding of Nb and N co-doping on the electronic structure and band gap of SnO_2 semiconductor, further corroborating results of the experimental study.

  15. 195Pt and 119Sn Knight shifts of U3Pt3Sn4

    International Nuclear Information System (INIS)

    Kojima, K.; Takabatake, T.; Harada, A.; Hihara, T.

    1995-01-01

    The 195 Pt and 119 Sn Knight shifts in U 3 Pt 3 Sn 4 have been measured in the temperature range 4.2-298K. They exhibit Curie-Weiss like behaviors above about 50K and remain constant below about 10K. This suggests that the deviation of χ(T) from the modified Curie-Weiss law is an intrinsic property of U 3 Pt 3 Sn 4 . ((orig.))

  16. Theoretical study of electronic structures and spectroscopic properties of Ga 3Sn, GaSn 3, and their ions

    Science.gov (United States)

    Zhu, Xiaolei

    2007-01-01

    Ground and excited states of mixed gallium stannide tetramers (Ga 3Sn, Ga 3Sn +, Ga 3Sn -, GaSn 3, GaSn 3+, and GaSn 3-) are investigated employing the complete active space self-consistent-field (CASSCF), density function theory (DFT), and the coupled-cluster single and double substitution (including triple excitations) (CCSD(T)) methods. The ground states of Ga 3Sn, Ga 3Sn +, and Ga 3Sn - are found to be the 2A 1, 3B 1, and 1A 1 states in C2v symmetry with a planar quadrilateral geometry, respectively. The ground states of GaSn 3 and GaSn 3- is predicted to be the 2A 1 and 1A 1 states in C2v point group with a planar quadrilateral structure, respectively, while the ground state of GaSn 3+ is the 1A 1 state with ideal triangular pyramid C3v geometry. Equilibrium geometries, vibrational frequencies, binding energies, electron affinities, ionization energies, and other properties of Ga 3Sn and GaSn 3 are computed and discussed. The anion photoelectron spectra of Ga 3Sn - and GaSn 3- are also predicted. It is interesting to find that the amount of charge transfer between Ga and Sn 2 atoms in the 1A 1 state of GaSn 3+ greatly increases upon electron ionization from the 2A 1 state of GaSn 3, which may be caused by large geometry change. On the other hand, the results of the low-lying states of Ga 3Sn and GaSn 3 are compared with those of Ga 3Si and GaSi 3.

  17. Effect of Sn addition on the microstructure and superelasticity in Ti-Nb-Mo-Sn alloys.

    Science.gov (United States)

    Zhang, D C; Yang, S; Wei, M; Mao, Y F; Tan, C G; Lin, J G

    2012-09-01

    Ti-7.5Nb-4Mo-xSn (x=0-4at%) alloys were developed as the biomedical materials. The effect of the Sn content on the microstructure and superelasticity of the alloys was investigated. It is found that Sn is a strong stabilizer of the β phase, which is effective in suppressing the formation of α″ and ω phases in the alloys. Moreover, the Sn addition has a significant impact on the mechanical properties of the alloys. With the increase of Sn addition, the yield stress of the alloys increase, but their elastic modulus, the fracture strength and the ductility decrease, and the deformation mode of the alloys changes from (322) twining to α″ transformation and then to slip. The Ti-7.5Nb-4Mo-1Sn and Ti-7.5Nb-4Mo-3Sn alloys exhibit a good superelasticity with a high σ(SIM) due to the relatively high athermal ω phases containing or the solution hardening at room temperature. Under the maximum strain of 5%, Ti-7.5Nb-4Mo-3Sn (at%) alloy exhibits higher super elastic stability than that of Ti-7.5Nb-4Mo-1Sn alloy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Fluid sensitive nanoscale switching with quantum levitation controlled by $\\alpha$-Sn/$\\beta$-Sn phase transition

    OpenAIRE

    Boström, Mathias; Dou, Maofeng; Malyi, Oleksandr I.; Parashar, Prachi; Parsons, Drew F.; Brevik, Iver; Persson, Clas

    2018-01-01

    We analyze the Lifshitz pressure between silica and tin separated by a liquid mixture of bromobenzene and chlorobenzene. We show that the phase transition from semimetallic α−Sn to metallic β−Sn can switch Lifshitz forces from repulsive to attractive. This effect is caused by the difference in dielectric functions of α−Sn and β−Sn, giving both attractive and repulsive contributions to the total Lifshitz pressure in different frequency regions controlled by the composition of the intervening l...

  19. Oxidation of Pb-Sn and Pb-Sn-In alloys

    International Nuclear Information System (INIS)

    Sluzewski, D.A.; Chang, Y.A.; Marcotte, V.C.

    1990-01-01

    Air oxidized Pb-Sn and Pb-Sn-In single phase alloys have been studied with scanning Auger microscopy. Line scans across grain boundaries combined with argon ion sputter etching revealed grain boundary oxidation. In the Pb-Sn samples, tin is preferentially oxidized with the grain boundary regions having a much higher percentage of tin oxide than the bulk surface oxide. In the Pb-Sn-In alloys, both tin and indium are preferentially oxidized with the grain boundary regions being enriched with tin and indium oxides

  20. Studies of CoSn grains in the carbon matrix structure of nanostructured tin–cobalt–carbon

    International Nuclear Information System (INIS)

    Ferguson, P.P.; Fleischauer, M.D.; LaForge, J.M.; Todd, A.D.W.; Li, P.; Dahn, J.R.

    2012-01-01

    Highlights: ► Sn–Co–C alloys as negative electrode for Li-ion batteries. ► Sn–Co–C alloys prepared by mechanical alloying and by sputtering. ► CoSn grains embedded in carbon matrix structure was observed from SANS and TEM. ► SANS quickly characterized Sn–Co–C alloys equivalently to TEM. - Abstract: Small angle neutron scattering (SANS) and transmission electron microscopy (TEM) have been used to qualitatively analyze the structure of Sn 30 Co 30 C 40 alloys produced by vertical axis mechanical attriting to those produced by magnetron sputter deposition. From SANS and TEM, CoSn grains embedded in a carbon matrix structure were observed for all samples. The size of CoSn grains in the attrited samples was approximately 10 ± 3 nm by both TEM and SANS, while that of the sputtered samples was about 7 times smaller.

  1. The crystallographic growth directions of Sn whiskers

    International Nuclear Information System (INIS)

    Stein, J.; Welzel, U.; Leineweber, A.; Huegel, W.; Mittemeijer, E.J.

    2015-01-01

    The growth directions of 55 Sn whiskers, i.e. the crystallographic orientation parallel to the whisker-growth axes, were determined using (i) a focused ion beam microscope for the determination of the physical growth angles of the whiskers with respect to a specimen (reference) coordinate system and (ii) an electron backscatter detector in a scanning electron microscope for the determination of the crystallographic orientation of the whiskers. The Sn whiskers were found to grow preferentially along low-index directions of the β-Sn crystal structure. The experimental findings of this study (and most of the results presented in the literature as well) were explained by applying, in a modified way, the Hartman–Perdok concept of periodic bond chains, i.e. chains of strong bonds running uninterruptedly through the structure, to the Sn whisker-growth phenomenon

  2. Discovery of 11 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Cacella, P.; Stone, G.; Fernandez, J. M.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Nicholls, B.; Post, R. S.

    2018-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from 14-cm telescopes in Hawaii, Texas, South Africa, and Chile, we discovered several new transient sources.

  3. Nb3Sn for Radio Frequency Cavities

    International Nuclear Information System (INIS)

    Godeke, A.

    2006-01-01

    In this article, the suitability of Nb3Sn to improve the performance of superconducting Radio-Frequency (RF) cavities is discussed. The use of Nb3Sn in RF cavities is recognized as an enabling technology to retain a very high cavity quality factor (Q0) at 4.2 K and to significantly improve the cavity accelerating efficiency per unit length (Eacc). This potential arises through the fundamental properties of Nb3Sn. The properties that are extensively characterized in the literature are, however, mainly related to improvements in current carrying capacity (Jc) in the vortex state. Much less is available for the Meissner state, which is of key importance to cavities. Relevant data, available for the Meissner state is summarized, and it is shown how this already validates the use of Nb3Sn. In addition, missing knowledge is highlighted and suggestions are given for further Meissner state specific research

  4. Beta-decay studies near 100Sn

    International Nuclear Information System (INIS)

    Rykaczewski, Krzysztof Piotr; Karny, M.; Batist, L.; Banu, A.; Becker, F.; Blazhev, A.; Burkard, K.; Bruchle, W.; Doring, J.; Faestermann, T.; Gorska, M.; Grawe, H.; Janas, Z.; Jungclaus, A.; Kavatsyuk, M.; Kavatsyuk, O.; Kirchner, R.; La Commara, M.; Mandal, S.; Mazzocchi, C.; Miernik, K.; Mukha, I.; Muralithar, S.; Plettner, C.; Plochocki, A.; Roeckl, E.; Romoli, M.; Schadel, M.; Schmidt, K.; Schwengner, R.; Zylicz, J.

    2005-01-01

    The β-decay of 102 Sn was studied by using high-resolution germanium detectors as well as a Total Absorption Spectrometer (TAS). A decay scheme has been constructed based on the γ-γ coincidence data. The total experimental Gamow-Teller strength B GT exp of 102 Sn was deduced from the TAS data to be 4.2(9). A search for β-delayed γ-rays of 100 Sn decay remained unsuccessful. However, a Gamow-Teller hindrance factor h = 2.2(3), and a cross-section of about 3nb for the production of 100 Sn in fusion-evaporation reaction between 58 Ni beam and 50 Cr target have been estimated from the data on heavier tin isotopes. The estimated hindrance factor is similar to the values derived for lower shell nuclei

  5. Coulomb excitation of {sup 107}Sn

    Energy Technology Data Exchange (ETDEWEB)

    DiJulio, D.D.; Cederkall, J.; Fahlander, C. [Lund University, Physics Department, 118, Lund (Sweden); Ekstroem, A. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Hjorth-Jensen, M. [University of Oslo, Department of Physics and Center of Mathematics for Applications, Oslo (Norway); Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, East Lansing, MI (United States); Albers, M.; Blazhev, A.; Fransen, C.; Geibel, K.; Hess, H.; Reiter, P.; Seidlitz, M.; Taprogge, J.; Warr, N. [University of Cologne, Institute of Nuclear Physics, Cologne (Germany); Bildstein, V.; Gernhaeuser, R.; Wimmer, K. [Technische Universitaet Muenchen, Physik Department E12, Garching (Germany); Darby, I.; Witte, H. de [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Davinson, T. [University of Edinburgh, Department of Physics and Astronomy, Edinburgh (United Kingdom); Diriken, J. [Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Studiecentrum voor Kernenergie/Centre d' Etude de l' energie Nucleaire (SCK CEN), Mol (Belgium); Goergen, A.; Siem, S.; Tveten, G.M. [University of Oslo, Department of Physics, Oslo (Norway); Iwanicki, J. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Lutter, R. [Ludwig-Maximilians-Universitaet Muenchen, Fakultaet fuer Physik, Garching (Germany); Scheck, M. [University of Liverpool, Oliver Lodge Laboratory, Liverpool (United Kingdom); Walle, J.V. de [PH Department, Geneva 23 (Switzerland); Voulot, D.; Wenander, F. [AB Department, Geneva 23 (Switzerland)

    2012-07-15

    The radioactive isotope {sup 107}Sn was studied using Coulomb excitation at the REX-ISOLDE facility at CERN. This is the lightest odd-Sn nucleus examined using this technique. The reduced transition probability of the lowest-lying 3/2{sup +} state was measured and is compared to shell-model predictions based on several sets of single-neutron energies relative to {sup 100}Sn. Similar to the transition probabilities for the 2{sup +} states in the neutron-deficient even-even Sn nuclei, the measured value is underestimated by shell-model calculations. Part of the strength may be recovered by considering the ordering of the d{sub 5/2} and g{sub 7/2} single-neutron states. (orig.)

  6. Synthesis, characterization and photocatalytic performance of SnS nanofibers and SnSe nanofibers derived from the electrospinning-made SnO{sub 2} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Li; Li, Dan; Dong, Xiangting; Ma, Qianli; Yu, Wensheng; Wang, Xinlu; Yu, Hui; Wang, Jinxian; Liu, Guixia, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)

    2017-11-15

    SnO{sub 2} nanofibers were fabricated by calcination of the electrospun PVP/SnCl{sub 4} composite nanofibers. For the first time, SnS nanofibers and SnSe nanofibers were successfully synthesized by double crucible sulfurization and selenidation methods via inheriting the morphology of SnO{sub 2} nanofibers used as precursors, respectively. X-ray diffraction (XRD) analysis shows SnS nanofibers and SnSe nanofibers are respectively pure orthorhombic phase with space group of Pbnm and Cmcm. Scanning electron microscope (SEM) observation indicates that the diameters of SnS nanofibers and SnSe nanofibers are respectively 140.54±12.80 nm and 96.52±14.17 nm under the 95 % confidence level. The photocatalytic activities of samples were studied by using rhodamine B (Rh B) as degradation agent. When SnS or SnSe nanofibers are employed as the photocatalysts, the respective degradation rates of Rh B solution under the ultraviolet light irradiation after 200 min irradiation are 92.55 % and 92.86 %. The photocatalytic mechanism and formation process of SnS and SnSe nanofibers are also provided. More importantly, this preparation technique is of universal significance to prepare other metal chalcogenides nanofibers. (author)

  7. The system SnTe-InSe

    International Nuclear Information System (INIS)

    Gurshumov, A.P.; Alidzhanov, M.A.; Aliev, A.S.; Gadzhiev, T.G.; Mamedov, N.A.

    1986-01-01

    This paper discusses the nature of the interaction and physicochemical properties of the alloys of the system SnTe-InSe. The DTA was performed on an NTR-74 pyrometer, XPA on a Dron-2.0 diffractometer and MSA on an MIM-7 metallographic microscope. The microhardness of the samples was determined on a PMT-3 microhardness tester. The congruently melting compound SnInTeSe and solid solutions based on the starting components are formed in the system

  8. Advances in Nb3Sn Performance

    International Nuclear Information System (INIS)

    Godeke, Arno

    2008-01-01

    Nb 3 Sn wires with non-Cu critical current densities (J c ) that surpass 3 kAmm -2 at 12 T and 4.2 K are commercially available in piece lengths longer than 10 km. Accelerator-type magnets that utilize these conductors have achieved record magnetic fields. This article summarizes key developments in the last decade that have led to these significant improvements in the performance of Nb 3 Sn wires.

  9. SnO2 Nanostructure as Pollutant Gas Sensors: Synthesis, Sensing Performances, and Mechanism

    Directory of Open Access Journals (Sweden)

    Brian Yuliarto

    2015-01-01

    Full Text Available A significant amount of pollutants is produced from factories and motor vehicles in the form of gas. Their negative impact on the environment is well known; therefore detection with effective gas sensors is important as part of pollution prevention efforts. Gas sensors use a metal oxide semiconductor, specifically SnO2 nanostructures. This semiconductor is interesting and worthy of further investigation because of its many uses, for example, as lithium battery electrode, energy storage, catalyst, and transistor, and has potential as a gas sensor. In addition, there has to be a discussion of the use of SnO2 as a pollutant gas sensor especially for waste products such as CO, CO2, SO2, and NOx. In this paper, the development of the fabrication of SnO2 nanostructures synthesis will be described as it relates to the performances as pollutant gas sensors. In addition, the functionalization of SnO2 as a gas sensor is extensively discussed with respect to the theory of gas adsorption, the surface features of SnO2, the band gap theory, and electron transfer.

  10. In situ 119Sn Moessbauer spectroscopy used to study lithium insertion in c-Mg2Sn

    International Nuclear Information System (INIS)

    Aldon, L.; Ionica, C. M.; Lippens, P. E.; Larcher, D.; Tarascon, J.-M.; Olivier-Fourcade, J.; Jumas, J.-C.

    2006-01-01

    The electrochemical reactions of Li with c-Mg 2 Sn have been investigated by in situ Moessbauer spectroscopy of 119 Sn and X-ray diffraction. The lithiation transforms initially c-Mg 2 Sn part into Li x Mg 2 Sn alloy (x 2 MgSn ternary alloy. In situ Moessbauer spectroscopy provides valuable information on local environment of tin and swelling behavior and cracking of the particles during discharge and charge processes.

  11. Temperature dependent growth and optical properties of SnO2 ...

    Indian Academy of Sciences (India)

    Administrator

    SEM micrographs of SnO2 nanowires and a single nanowire of diameter 50–60 .... the size of the nanoparti- cles may control the thickness and morphology of resul- ... from the analysis of peak shapes and the selection rules. XRD and electron ...

  12. Enhancing performances of a resistivity-type hydrogen sensor based on Pd/SnO2/RGO nanocomposites.

    Science.gov (United States)

    Peng, Yitian; Zheng, Lulu; Zou, Kun; Li, Cong

    2017-05-26

    Palladium/tin oxide/reduced graphene oxide (Pd/SnO 2 /RGO) nanocomposites with Pd and SnO 2 crystalline nanoparticles of high density and uniformity coated on RGO have been synthesized by a two-step reduction process. A novel hydrogen (H 2 ) sensor based on Pd/SnO 2 /RGO nanocomposites was fabricated by placing Pd/SnO 2 /RGO nanocomposites onto a pair of gold electrodes. The Pd/SnO 2 /RGO nanocomposite-based sensor exhibited higher responses than Pd/RGO to H 2 because the introduction of SnO 2 nanoparticles enhances H 2 adsorption and forms a P-N junction with RGO. The sensor shows a high response of 55% to 10 000 ppm H 2 , and a low detection limit, fast response, good selectivity and repeatability due to a combination effect of the Pd and SnO 2 nanoparticles. The studies provide a novel strategy for great potential applications of graphene-based gas sensors.

  13. Carbon-doped SnS2 nanostructure as a high-efficiency solar fuel catalyst under visible light.

    Science.gov (United States)

    Shown, Indrajit; Samireddi, Satyanarayana; Chang, Yu-Chung; Putikam, Raghunath; Chang, Po-Han; Sabbah, Amr; Fu, Fang-Yu; Chen, Wei-Fu; Wu, Chih-I; Yu, Tsyr-Yan; Chung, Po-Wen; Lin, M C; Chen, Li-Chyong; Chen, Kuei-Hsien

    2018-01-12

    Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS 2 (SnS 2 -C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO 2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS 2 lattice, resulting in different photophysical properties as compared with undoped SnS 2 . This SnS 2 -C photocatalyst significantly enhances the CO 2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS 2 -C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO 2 reduction under visible light, where the in situ carbon-doped SnS 2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.

  14. Fabrication of folic acid sensor based on the Cu doped SnO2 nanoparticles modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Lavanya, N; Radhakrishnan, S; Sudhan, N; Sekar, C; Leonardi, S G; Neri, G; Cannilla, C

    2014-01-01

    A novel folic acid biosensor has been fabricated using Cu doped SnO 2 nanoparticles (NPs) synthesized by a simple microwave irradiation method. Powder XRD and TEM studies confirmed that both the pure and Cu doped SnO 2 (Cu: 0, 10, 20wt%) crystallized in tetragonal rutile-type structure with spherical morphology. The average crystallite size of pure SnO 2 was estimated to be around 16 nm. Upon doping, the crystallite sizes decreased to 9 nm and 5 nm for 10 and 20wt% Cu doped SnO 2 respectively. XPS studies confirmed the electronic state of Sn and Cu to be 4+ and 2+ respectively. Cu (20wt%) doped SnO 2 NPs are proved to be a good sensing element for the determination of folic acid (FA). Cu-SnO 2 NPs (20wt%) modified glassy carbon electrode (GCE) exhibited the lowest detection limit of 0.024 nM over a wide folic acid concentration range of 1.0 × 10 −10 to 6.7 × 10 −5 M at physiological pH of 7.0. The fabricated sensor is highly selective towards the determination of FA even in the presence of a 100 fold excess of common interferent ascorbic acid. The sensor proved to be useful for the estimation of FA content in pharmaceutical sample with satisfactory recovery. (paper)

  15. The influence of executive capacity on selective attention and subsequent processing

    Directory of Open Access Journals (Sweden)

    Kirk R. Daffner

    2012-06-01

    Full Text Available Recent investigations that suggest selective attention is dependent on top-down control mechanisms lead to the expectation that individuals with high executive capacity would exhibit more robust neural indices of selective attention. This prediction was tested by using event-related potentials (ERPs to examine differences in markers of information processing across 25 subjects divided into 2 groups based on high vs. average executive capacity, as defined by neuropsychological test scores. Subjects performed an experimental task requiring selective attention to a specified color. In contrast to expectation, individuals with high and average executive capacity did not differ in the size of ERP indices of selective attention: the anterior Selection Positivity (SP and posterior Selection Negativity (SN. However, there were substantial differences between groups in markers of subsequent processing, including the anterior N2 (a measure of attentional control and the P3a (an index of the orienting of attention. Executive capacity predicted speed of processing at both early and late attentional stages. Individuals with lower executive capacity exhibited prolonged SN, P3a, and P3b latencies. However, the delays in carrying out selective attention operations did not account for subsequent delays in decision making, or explain excessive orienting and reduced attentional control mechanisms in response to stimuli that should have been ignored. SN latency, P3 latency, and the size of the anterior N2 made independent contributions to the variance of executive capacity. In summary, our findings suggest that current views regarding the relationship between top-down control mechanisms and selective attention may need refinement.

  16. Band Alignments, Valence Bands, and Core Levels in the Tin Sulfides SnS, SnS2, and Sn2S3: Experiment and Theory

    OpenAIRE

    Whittles, TJ; Burton, LA; Skelton, JM; Walsh, A; Veal, TD; Dhanak, VR

    2016-01-01

    Tin sulfide solar cells show relatively poor efficiencies despite attractive photovoltaic properties, and there is difficulty in identifying separate phases, which are also known to form during Cu2ZnSnS4 depositions. We present X-ray photoemission spectroscopy (XPS) and inverse photoemission spectroscopy measurements of single crystal SnS, SnS2, and Sn2S3, with electronic-structure calculations from density functional theory (DFT). Differences in the XPS spectra of the three phases, including...

  17. NMR Insights into the Unexpected Interaction of SnCl4 with D-Glucosamine and Its Effect on 5-HMF Preparation in ZnCl2 Molten Salt Hydrate Medium

    DEFF Research Database (Denmark)

    Chen, Chunyan; Ge, Wenzhi; Jia, Lingyu

    2016-01-01

    SnCl4, a versatile Lewis acid catalyst in the biomass conversion, plays a positive role for the cellulose biomass conversion but negative for chitin biomass conversion as realized in our previous research. In this report, the unexpected effects of SnCl4 on the conversion of d-glucosamine (GlcNH2)...

  18. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2015-07-01

    Full Text Available A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, and 0.75. The formation of Ni-Sn alloy species was mainly depended on the composition and temperature of H2 treatment. Intermetallics Ni-Sn that contain Ni3Sn, Ni3Sn2, and Ni3Sn4 alloy phases are known to be effective heterogeneous catalysts for levulinic acid hydrogenation giving very excellence g-valerolactone yield of >99% at 433 K, initial H2 pressure of 4.0 MPa within 6 h. The effective hydrogenation was obtained in H2O without the formation of by-product. Intermetallic Ni-Sn(1.5 that contains Ni3Sn2 alloy species demonstrated very stable and reusable catalyst without any significant loss of its selectivity. © 2015 BCREC UNDIP. All rights reserved. Received: 26th February 2015; Revised: 16th April 2015; Accepted: 22nd April 2015  How to Cite: Rodiansono, R., Astuti, M.D., Ghofur, A., Sembiring, K.C. (2015. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 192-200. (doi:10.9767/bcrec.10.2.8284.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8284.192-200  

  19. Preparation, deformation, and failure of functional Al-Sn and Al-Sn-Pb nanocrystalline alloys

    Science.gov (United States)

    Noskova, N. I.; Vil'Danova, N. F.; Filippov, Yu. I.; Churbaev, R. V.; Pereturina, I. A.; Korshunov, L. G.; Korznikov, A. V.

    2006-12-01

    Changes in the structure, hardness, mechanical properties, and friction coefficient of Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb (wt %) alloys subjected to severe plastic deformation by equal-channel angular pressing (with a force of 40 tonne) and by shear at a pressure of 5 GPa have been studied. The transition into the nanocrystalline state was shown to occur at different degrees of plastic deformation. The hardness exhibits nonmonotonic variations, namely, first it increases and subsequently decreases. The friction coefficient of the Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys quenched from the melt was found to be 0.33; the friction coefficients of these alloys in the submicrocrystalline state (after equal-channel angular pressing) equal 0.24, 0.32, and 0.35, respectively. The effect of disintegration into nano-sized powders was found to occur in the Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys after severe plastic deformation to ɛ = 6.4 and subsequent short-time holding.

  20. Pion-induced fission of 209Bi and 119Sn: measurements, calculations, analyses and comparison

    International Nuclear Information System (INIS)

    Rana, M.A.; Sher, G.; Manzoor, S.; Shehzad, M.I.

    2011-01-01

    Cross-sections for the π - -induced fission of 209 Bi and 119 Sn have been measured using the most sensitive CR-39 solid-state nuclear track detector. In experiments, target–detector stacks were exposed to negative pions of energy 500, 672, 1068, and 1665 MeV at the Brookhaven National Laboratory, USA. An important aspect of the present paper is the comparison of pion-induced fission fragment spectra of above mentioned nuclei with the spontaneous fission fragment spectra of 252 Cf. This comparison is made in terms of fission fragment track lengths in the CR-39 detectors. Measurement results are compared with calculations of Monte Carlo and statistical weight functions methods using the computer code CEM95. Agreement between measurements and calculations is fairly good for 209 Bi target nuclei whereas it is indigent for the case of 119 Sn. The possibilities of the trustworthy calculations, using the computer code CEM95, comparable with measurements of pion-induced fission in intermediate and heavy nuclei are explored by employing various systematics available in the code. Energy dependence of pion-induced fission in 119 Sn and 209 Bi is analyzed employing a newly defined parameter geometric-size-normalized fission cross-section (χ f g ). It is found that the collective nuclear excitations, which may lead to fission, become more probable for both 209 Bi and 119 Sn nuclei with increasing energy of negative pions from 500 to 1665 MeV. (author)

  1. Electronic and magnetic properties of rare earth-Sn3 compounds for 119Sn Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Sanchez, J.P.; Friedt, J.M.; Shenoy, G.K.; Percheron, A.; Achard, J.C.

    1975-01-01

    The electronic and magnetic properties of RESn 3 compounds (RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Yb) have been investigated using the 23.8keV Moessbauer resonance of 119 Sn. The isomer shifts and quadrupole interactions are nearly the same in all compounds. The transferred magnetic fields and their orientation with respect to the principal electric field gradient axis at various Sn sites in the magnetically ordered state of RESn 3 (RE=Pr, Nd, Sm, Eu, Gd) have been utilized to get information about the magnetic structure. An evaluation of the transferred fields in PrSn 3 and NdSn 3 shows that the spin density at the Sn nucleus is nearly the same in both compounds [fr

  2. Liquidus Projection and Isothermal Section of the Sb-Se-Sn System

    Science.gov (United States)

    Chang, Jui-shen; Chen, Sinn-wen

    2017-12-01

    Sb-Se-Sn ternary alloys are promising chalcogenide materials. The liquidus projection and 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system are determined. Numerous Sb-Se-Sn alloys are prepared, and their primary solidification phases are examined. In addition to the three terminal phases, (Sb), (Se) and (Sn), there are Sb2Sn3, SbSn, SnSe, SnSe2, Sb2Se3, Sn2Sb9Se9, and SnSb2Se4 phases. In addition, there are two miscibility gaps along the Sb-Se and Se-Sn and sides. There are ten invariant reactions in the Sb-Se-Sn ternary system, and seven of them are experimentally determined in this study. The lowest reaction temperature of determined invariant reaction is L + SbSn = (Sn) + SnSe at 515.4 K ± 5 K (242.2 °C ± 5 °C). There are nine tie-triangles, which are Liquid + SbSn + SnSe, SbSn + SnSe + (Sb), SnSe + (Sb) + Sn2Sb9Se9, (Sb) + Sb2Se3 + Sn2Sb9Se9, SnSe + Sn2Sb9Se9 + SnSb2Se4, Sb2Se3 + Sn2Sb9Se9 + SnSb2Se4, SnSe + SnSe2 + SnSb2Se4, SnSe2 + SnSb2Se4 + Sb2Se3, and SnSe2 + Sb2Se3 + Liquid in the 673.2 K (400 °C) isothermal section of the Sb-Se-Sn ternary system.

  3. Deposition and characterization of single magnetron deposited Fe:SnO{sub x} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Kormunda, Martin, E-mail: martin.kormunda@ujep.cz [J.E. Purkinje University, Faculty of Science, Department of Physics, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic); Fischer, Daniel; Hertwig, Andreas; Beck, Uwe [BAM Federal Institute for Materials Research and Testing, Division 6 4 Surface Technologies, Unter den Eichen 44-46, 12203 Berlin (Germany); Sebik, Matej; Pavlik, Jaroslav [J.E. Purkinje University, Faculty of Science, Department of Physics, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic); Esser, Norbert [Leibniz-Institut für Analytische Wissenschaften — ISAS e.V., Department Berlin, Schwarzschildstr. 12, 12489 Berlin (Germany)

    2015-11-30

    Coatings deposited by magnetron co-sputtering from a single RF magnetron with a ceramic SnO{sub 2} target with iron inset in argon plasma were studied. The mass spectra of the process identified Sn{sup +} and SnO{sup +} species as the dominant species sputtered from the target, but no SnO{sub 2}{sup +} species were detected. The dominant positive ions in argon plasma are Ar{sup +} species. The only detected negative ions were O{sup −}. Sputtered neutral tin related species were not detected. Iron related species were also not detected because their concentration is below the detection limit. The concentration of iron dopant in the tin oxide coatings was controlled by the RF bias applied on the substrate holder while the discharge pressure also has some influence. The iron concentration was in the range from 0.9 at.% up to 19 at.% increasing with the substrate bias while the sheet resistivity decreases. The stoichiometry ratio of O/(Sn + Fe) in the coatings increased from 1.7 up to 2 in dependence on the substrate bias from floating bias (− 5 V) up to − 120 V of RF self-bias, respectively. The tin in the coatings was mainly bonded in Sn{sup 4+} state and iron was mainly in Fe{sup 2+} state when other tin bonding states were detected only in a small amounts. Iron bonding states in contrary to elemental compositions of the coatings were not influenced by the RF bias applied on the substrate. The coatings showed high transparency in the visible spectral range. However, an increased metallic behavior could be detected by using a higher RF bias for the deposition. The X-ray diffraction patterns and electron microscopy pictures made on the coatings confirmed the presence of an amorphous phase. - Highlights: • RF magnetron sputtering of SnO{sub 2} target with Fe inset in argon investigated by mass spectrometry • Optical properties of Fe doped SnO{sub x} coatings characterized • Analyses of overlapped XPS peaks at a spectrum from Fe doped SnO{sub x} coatings

  4. Preparation of SnO 2 /Carbon Composite Hollow Spheres and Their Lithium Storage Properties

    KAUST Repository

    Lou, Xiong Wen; Deng, Da; Lee, Jim Yang; Archer, Lynden A.

    2008-01-01

    In this work, we present a novel concept of structural design for preparing functional composite hollow spheres and derived double-shelled hollow spheres. The approach involves two main steps: preparation of porous hollow spheres of one component and deposition of the other component onto both the interior and exterior surfaces of the shell as well as in the pores. We demonstrate the concept by preparing SnO2/carbon composite hollow spheres and evaluate them as potential anode materials for lithium-ion batteries. These SnO2/carbon hollow spheres are able to deliver a reversible Li storage capacity of 473 mA h g-1 after 50 cycles. Unusual double-shelled carbon hollow spheres are obtained by selective removal of the sandwiched porous SnO2 shells. © 2008 American Chemical Society.

  5. Decay spectroscopy with EURICA in the region of {sup 100}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Faestermann, Thomas; Gernhaeuser, Roman; Lubos, Daniel; Steiger, Konrad [Technische Universitaet Muenchen (Germany); Collaboration: EURICA RIBF09-Collaboration

    2015-07-01

    The most recent experiment on properties of nuclei in the region of {sup 100}Sn has been performed at the radioisotope beam factory (RIBF) at the RIKEN Nishina Center. For the decay spectroscopy, we used the detector arrays EURICA and WASABI which consist of Ge- and LaBr- as well as Si-detectors, respectively. The experiment has revealed new nuclei along the N=Z-2 line and an increase of statistics by a factor of ∝10 for N=Z-1 nuclei and {sup 100}Sn compared to previous experiments. The presentation gives an overview on the dedicated high efficiency setup and the experimental program. A status of the on-going analysis with regard to {sup 100}Sn and selected results for several nuclei and isomers in this region will be discussed.

  6. Preparation of SnO 2 /Carbon Composite Hollow Spheres and Their Lithium Storage Properties

    KAUST Repository

    Lou, Xiong Wen

    2008-10-28

    In this work, we present a novel concept of structural design for preparing functional composite hollow spheres and derived double-shelled hollow spheres. The approach involves two main steps: preparation of porous hollow spheres of one component and deposition of the other component onto both the interior and exterior surfaces of the shell as well as in the pores. We demonstrate the concept by preparing SnO2/carbon composite hollow spheres and evaluate them as potential anode materials for lithium-ion batteries. These SnO2/carbon hollow spheres are able to deliver a reversible Li storage capacity of 473 mA h g-1 after 50 cycles. Unusual double-shelled carbon hollow spheres are obtained by selective removal of the sandwiched porous SnO2 shells. © 2008 American Chemical Society.

  7. A rapid hydrothermal synthesis of rutile SnO2 nanowires

    International Nuclear Information System (INIS)

    Lupan, O.; Chow, L.; Chai, G.; Schulte, A.; Park, S.; Heinrich, H.

    2009-01-01

    Tin oxide (SnO 2 ) nanowires with rutile structure have been synthesized by a facile hydrothermal method at 98 deg. C. The morphologies and structural properties of the as-grown nanowires/nanoneedles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction, X-ray diffraction and Raman spectroscopy. The SEM images reveal tetragonal nanowires of about 10-100 μm in length and 50-100 nm in radius. The Raman scattering peaks indicate a typical rutile phase of the SnO 2 . The effects of molar ratio of SnCl 4 to NH 4 OH on the growth mechanism are discussed

  8. Ultra Fast Timing Measurements at $^{78}$Ni and $^{132}$Sn

    CERN Multimedia

    2002-01-01

    We propose to measure level lifetimes in the exotic nuclei of $^{81}$Ga and $^{80}$Ga in the vicinity of $^{78}$Ni and of $^{135}$Sb and $^{134}$Sb above $^{132}$Sn by the time-delayed technique. These are relatively simple nuclear systems with a few particles and/or holes outside of the doubly-magic core thus can be treated rather precisely within the shell model. The anticipated new structure information on these nuclei, and in particular the lifetime results will put constraints on the model parameters and will serve to verify their predictions. The selected nuclei are some of the most exotic ones just above $^{78}$Ni or $^{132}$Sn, where the transition rates can be studied at present. Of the strongest interest is the nucleus of $^{81}$Ga, which has only 3 valence protons outside of $^{78}$Ni with the lowest proton orbits being $p_{3/2}$ and $f_{5/2}$. The Ml transition between these states, although allowed by the selection rules, should be $\\textit{l}$-forbidden thus very slow. This should give rise to a...

  9. H2S Sensing by Hybrids Based on Nanocrystalline SnO2 Functionalized with Cu(II Organometallic Complexes: The Role of the Ligand Platform

    Directory of Open Access Journals (Sweden)

    Marina Rumyantseva

    2017-11-01

    Full Text Available This paper deals with the functionalization of nanocrystalline SnO2 with Cu(II complexes with organic ligands, aimed at the improvement of sensor selectivity towards gas molecules. For the synthesis of metalorganic/SnO2 hybrid material complexes of Cu(II with phthalocyanine, porphyrinines, bipyridine and azadithiacrown etherwere used. The analysis of gas sensor properties showed the possibility of increasing the sensitivity and selectivity of hybrid materials in H2S detection due to the electron transfer from SnO2 to an adsorbed organic molecule, which changes during the interaction between H2S and Cu(II ions.

  10. Nanocrystalline CdSnO3 Based Room Temperature Methanol Sensor

    Directory of Open Access Journals (Sweden)

    Shanabhau BAGUL

    2017-04-01

    Full Text Available Synthesis of nanocrystalline CdSnO3 powder by ultrasonic atomizer assisted wet chemical method is reported in this paper. Synthesized CdSnO3 powder was characterized by X-Ray Diffraction (XRD, Field Emission Scanning Electron Microscopy (FESEM and Transmission Electron Microscopy (TEM to examine phase and microstructure. FESEM and TEM analysis reveals that the CdSnO3 powder prepared here is porous monodisperse nanocrystalline in nature, with average particle size of approximately 17 nm or smaller. The material is also characterized by UV-Visible and Photoluminescence (PL spectroscopy. Thick films of synthesized CdSnO3 powder fired at 850 0C are made by using screen printing method. The films surface is modified by using dipping method. CuCl2 (0.005 M dipped (for 2 min thick film shows high response (R= 477 to 100 ppm methanol at room temperature (35 0C. The sensor shows good selectivity and fast response recovery time to methanol. The excellent methanol sensing performance, particularly high response values is observed to be mainly due to porous CdSnO3 surface.

  11. CO oxidation catalyzed by ag nanoparticles supported on SnO/CeO2

    KAUST Repository

    Khan, Inayatali

    2015-01-01

    Ag-Sn/CeO2 catalysts were synthesized by the co-precipitation method with different Ag-Sn wt.% loadings and were tested for the oxidation of CO. The catalysts were characterized by powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), and selected area electron diffraction (SAED) techniques. UV-Vis measurements were carried out to elucidate the ionic states of the silver particles, and the temperature-programmed reduction (TPR) technique was employed to check the reduction temperature of the catalyst supported on CeO2. There are peaks for silver crystallites in the X-ray diffraction patterns and the presence of SnO was not well evidenced by the XRD technique due to sintering inside the 3D array channels of CeO2 during the calcination process. The Ag-Sn/CeO2 (4%) catalyst was the most efficient and exhibited 100% CO oxidation at 100 °C due to small particle size and strong electronic interaction with the SnO/CeO2 support. © 2015 Sociedade Brasileira de Química.

  12. SnO2 Nanoparticle-Based Passive Capacitive Sensor for Ethylene Detection

    Directory of Open Access Journals (Sweden)

    Mangilal Agarwal

    2012-01-01

    Full Text Available A passive capacitor-based ethylene sensor using SnO2 nanoparticles is presented for the detection of ethylene gas. The nanoscale particle size (10 nm to 15 nm and film thickness (1300 nm of the sensing dielectric layer in the capacitor model aid in sensing ethylene at room temperature and eliminate the need for microhotplates used in existing bulk SnO2-resistive sensors. The SnO2-sensing layer is deposited using room temperature dip coating process on flexible polyimide substrates with copper as the top and bottom plates of the capacitor. The capacitive sensor fabricated with SnO2 nanoparticles as the dielectric showed a total decrease in capacitance of 5 pF when ethylene gas concentration was increased from 0 to 100 ppm. A 7 pF decrease in capacitance was achieved by introducing a 10 nm layer of platinum (Pt and palladium (Pd alloy deposited on the SnO2 layer. This also improved the response time by 40%, recovery time by 28%, and selectivity of the sensor to ethylene mixed in a CO2 gas environment by 66%.

  13. THE RISE OF SN 2014J IN THE NEARBY GALAXY M82

    International Nuclear Information System (INIS)

    Goobar, A.; Johansson, J.; Amanullah, R.; Ferretti, R.; Cao, Y.; Perley, D. A.; Tendulkar, S. P.; Kasliwal, M. M.; Nugent, P. E.; Harris, C.; Gal-Yam, A.; Ofek, E. O.; Dennefeld, M.; Valenti, S.; Arcavi, I.; Banerjee, D. P. K.; Venkataraman, V.; Joshi, V.; Ashok, N. M.; Cenko, S. B.

    2014-01-01

    We report on the discovery of SN 2014J in the nearby galaxy M82. Given its proximity, it offers the best opportunity to date to study a thermonuclear supernova (SN) over a wide range of the electromagnetic spectrum. Optical, near-IR, and mid-IR observations on the rising light curve, orchestrated by the intermediate Palomar Transient Factory, show that SN 2014J is a spectroscopically normal Type Ia supernova (SN Ia), albeit exhibiting high-velocity features in its spectrum and heavily reddened by dust in the host galaxy. Our earliest detections start just hours after the fitted time of explosion. We use high-resolution optical spectroscopy to analyze the dense intervening material and do not detect any evolution in the resolved absorption features during the light curve rise. Similar to other highly reddened SNe Ia, a low value of total-to-selective extinction, R V ≲ 2, provides the best match to our observations. We also study pre-explosion optical and near-IR images from Hubble Space Telescope with special emphasis on the sources nearest to the SN location

  14. Hydrothermal Synthesis of Pt-, Fe-, and Zn-doped SnO2 Nanospheres and Carbon Monoxide Sensing Properties

    Directory of Open Access Journals (Sweden)

    Weigen Chen

    2013-01-01

    Full Text Available Pure and M-doped (M = Pt, Fe, and Zn SnO2 nanospheres were successfully synthesized via a simple and facile hydrothermal method and characterized by X-ray powder diffraction, field-emission scanning electron microscopy, and energy dispersive spectroscopy. Chemical gas sensors were fabricated based on the as-synthesized nanostructures, and carbon monoxide sensing properties were systematically measured. Compared to pure, Fe-, and Zn-doped SnO2 nanospheres, the Pt-doped SnO2 nanospheres sensor exhibits higher sensitivity, lower operating temperature, more rapid response and recovery, better stability, and excellent selectivity. In addition, a theoretical study based on the first principles calculation was conducted. All results demonstrate the potential of Pt dopant for improving the gas sensing properties of SnO2-based sensors to carbon monoxide.

  15. Predictive value and clinical utility of centrally assessed ER, PgR, and Ki-67 to select adjuvant endocrine therapy for premenopausal women with hormone receptor-positive, HER2-negative early breast cancer: TEXT and SOFT trials.

    Science.gov (United States)

    Regan, Meredith M; Pagani, Olivia; Francis, Prudence A; Fleming, Gini F; Walley, Barbara A; Kammler, Roswitha; Dell'Orto, Patrizia; Russo, Leila; Szőke, János; Doimi, Franco; Villani, Laura; Pizzolitto, Stefano; Öhlschlegel, Christian; Sessa, Fausto; Peg Cámara, Vicente; Rodríguez Peralto, José Luis; MacGrogan, Gaëtan; Colleoni, Marco; Goldhirsch, Aron; Price, Karen N; Coates, Alan S; Gelber, Richard D; Viale, Giuseppe

    2015-11-01

    The SOFT and TEXT randomized phase III trials investigated adjuvant endocrine therapies for premenopausal women with hormone receptor-positive (HR+) early breast cancer. We investigated the prognostic and predictive value of centrally assessed levels of estrogen receptor (ER), progesterone receptor (PgR), and Ki-67 expression in women with HER2-negative disease. Of 5707 women enrolled, 4115 with HER2-negative (HR+/HER2-) disease had ER, PgR, and Ki-67 centrally assessed by immunohistochemistry. Breast cancer-free interval (BCFI) was defined from randomization to first invasive local, regional, or distant recurrence or contralateral breast cancer. The prognostic and predictive values of ER, PgR and Ki-67 expression levels were assessed using Cox modeling and STEPP methodology. In this HR+/HER2- population, the median ER, PgR, and Ki-67 expressions were 95, 90, and 18 % immunostained cells. As most patients had strongly ER-positive tumors, the predictive value of ER levels could not be investigated. Lower PgR and higher Ki-67 expression were associated with reduced BCFI. There was no consistent evidence of heterogeneity of the relative treatment effects according to PgR or Ki-67 expression levels, though there was a greater 5-year absolute benefit of exemestane + ovarian function suppression (OFS) versus tamoxifen with or without OFS at lower levels of PgR and higher levels of Ki-67. Women with poor prognostic features of low PgR and/or high Ki-67 have greater absolute benefit from exemestane + OFS versus tamoxifen + OFS or tamoxifen alone, but individually PgR and Ki-67 are of limited predictive value for selecting adjuvant endocrine therapy for premenopausal women with HR+/HER2- early breast cancer.

  16. Noncollinear antiferromagnetic Mn3Sn films

    Science.gov (United States)

    Markou, A.; Taylor, J. M.; Kalache, A.; Werner, P.; Parkin, S. S. P.; Felser, C.

    2018-05-01

    Noncollinear hexagonal antiferromagnets with almost zero net magnetization were recently shown to demonstrate giant anomalous Hall effect. Here, we present the structural and magnetic properties of noncollinear antiferromagnetic Mn3Sn thin films heteroepitaxially grown on Y:ZrO2 (111) substrates with a Ru underlayer. The Mn3Sn films were crystallized in the hexagonal D 019 structure with c -axis preferred (0001) crystal orientation. The Mn3Sn films are discontinuous, forming large islands of approximately 400 nm in width, but are chemical homogeneous and characterized by near perfect heteroepitaxy. Furthermore, the thin films show weak ferromagnetism with an in-plane uncompensated magnetization of M =34 kA/m and coercivity of μ0Hc=4.0 mT at room temperature. Additionally, the exchange bias effect was studied in Mn3Sn /Py bilayers. Exchange bias fields up to μ0HEB=12.6 mT can be achieved at 5 K. These results show Mn3Sn films to be an attractive material for applications in antiferromagnetic spintronics.

  17. Zr-Sn-Nb alloys. Preliminary studies

    International Nuclear Information System (INIS)

    Danon, C.A.; Arias, D.E.

    1993-01-01

    Studies of the Zr-Sn-Nb diagram have been started, focussing on the Zr-rich corner, near the composition of Zirlo commercial alloy, Zr-1Sn-1Nb, and with Fe and O contents usual in nuclear grade materials. Three alloys were melted, namely Zr-4Sn-2.4Nb (A), Zr-1Sn-3Nb (B) and Zr-2.1Sn-1Nb (C). α/β transformation temperatures were measured through the variation of electrical resistivity(p) vs temperature (T). Values of 560 deg C, 670 deg C and 750 deg C were measured for the α→α+β reaction and 980 deg C, 910 deg C and 1000 deg C for the α+β→β reaction, for the A, B and C alloys, respectively in that order. Some samples were submitted to heat treatments (62 and 216 hours at 825 deg C, 120 hours at 875 deg C). Optical and scanning electronic microscopy of those samples confirmed our resistivity results. (Author)

  18. Fatigue and thermal fatigue of Pb-Sn solder joints

    International Nuclear Information System (INIS)

    Frear, D.; Grivas, D.; McCormack, M.; Tribula, D.; Morris, J.W. Jr.

    1987-01-01

    This paper presents a fundamental investigation of the fatigue and thermal fatigue characteristics, with an emphasis on the microstructural development during fatigue, of Sn-Pb solder joints. Fatigue tests were performed in simple shear on both 60Sn-40Pb and 5Sn-95Pb solder joints. Isothermal fatigue tests show increasing fatigue life of 60Sn-40Pb solder joints with decreasing strain and temperature. In contrast, such behavior was not observed in the isothermal fatigue of 5Sn-95Pb solder joints. Thermal fatigue results on 60Sn-40Pb solder cycled between -55 0 C and 125 0 C show that a coarsened region develops in the center of the joint. Both Pb-rich and Sn-rich phases coarsen, and cracks form within these coarsened regions. The failure mode 60Sn-40Pb solder joints in thermal and isothermal fatigue is similar: cracks form intergranularly through the Sn-rich phase or along Sn/Pb interphase boundaries. Extensive cracking is found throughout the 5Sn-95Pb joint for both thermal and isothermal fatigue. In thermal fatigue the 5Sn-95Pb solder joints failed after fewer cycles than 60Sn-40Pb

  19. LPG and NH3 Sensing Properties of SnO2 Thick Film Resistors Prepared by Screen Printing Technique

    Directory of Open Access Journals (Sweden)

    A. S. GARDE

    2010-11-01

    Full Text Available The gas sensing behavior of SnO2 thick film resistors deposited on alumina substrates has been investigated for LPG and NH3 gas. The standard screen printing technology was used to prepare the thick films. The films were fired at optimized temperature of 780 0C for 30 minutes. The material characterization was performed by XRD, SEM, FTIR, UV and EDAX for elemental analysis. IR spectroscopy analysis at 2949.26 cm-1 showed the peak assigned to the –Sn-H vibration due to the effect of hybridization i.e. sp3 and the sharp peak at 3734.31 cm-1 assigned to –Sn-OH stretching vibration due to hydrogen bonding. The variation of D.C electrical resistance of SnO2 film samples was measured in air as well as in LPG and NH3 gas atmosphere as a function of temperature. The SnO2 film samples show negative temperature coefficient of résistance. The SnO2 film samples showed the highest sensitivity to 600 ppm of LPG at 230 0C and NH3 at 370 0C. The effect of microstructure on sensitivity, response time and recovery time of the sensor in the presence of LPG and NH3 gases were studied and discussed.

  20. Ultraviolet emission from low resistance Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires

    Directory of Open Access Journals (Sweden)

    E. Karageorgou

    2014-11-01

    Full Text Available SnO2 and Sn:In2O3 nanowires were grown on Si(001, and p-n junctions were fabricated in contact with p-type Cu2S which exhibited rectifying current–voltage characteristics. Core-shell Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires were obtained by depositing copper and post-growth processing under H2S between 100 and 500 °C. These consist mainly of tetragonal rutile SnO2 and cubic bixbyite In2O3. We observe photoluminescence at 3.65 eV corresponding to band edge emission from SnO2 quantum dots in the Cu2SnS3/SnO2 nanowires due to electrostatic confinement. The Cu2SnS3/SnO2 nanowires assemblies had resistances of 100 Ω similar to CuInS2/In2O3 nanowires which exhibited photoluminescence at 3.0 eV.

  1. Microwave sinthesys and characterization of Pt and Pt-Rh-Sn electrocatalysts for ethanol oxidation

    Directory of Open Access Journals (Sweden)

    Jovanović Vladislava M.

    2011-01-01

    Full Text Available Carbon supported Pt and Pt-Rh-Sn catalysts were synthesized by microwave-polyol method in ethylene glycol solution and investigated for the ethanol electro-oxidation reaction. The catalysts were characterized in terms of structure, morphology and composition by employing XRD, STM and EDX techniques. STM analysis indicated rather uniform particles and particle size of below 2 nm for both catalysts. XRD analysis of the Pt/C catalyst revealed two phases, one with the main characteristic peaks of face centered cubic crystal structure (fcc of platinum and another related to graphite like structure of carbon support Vulcan XC-72R. However, in XRD pattern of the Pt-Rh-Sn/C catalyst diffraction peaks for Pt, Rh or Sn cannot be resolved, indicating an extremely low crystallinity. The small particle sizes and homogeneous size distributions of both catalysts should be attributed to the advantages of microwave assisted modified polyol process in ethylene glycol solution. Pt-Rh- Sn/C catalyst is highly active for the ethanol oxidation with the onset potential shifted for more than 150 mV to negative values and with currents nearly 5 times higher in comparison to Pt/C catalyst. The stability tests of the catalysts, as studied by the chronoamperometric experiments, reveal that the Pt-Rh-Sn/C catalyst is evidently less poisoned then Pt/C catalyst. The increased activity of Pt-Rh-Sn/C in comparison to Pt/C catalyst is most probably promoted by bifunctional mechanism and the electronic effect of alloyed metals.

  2. Phase diagram of SnTe-CdSe cross-section of SnTe+CdSe reversible SnSe+CdTe ternary reciprocal system

    International Nuclear Information System (INIS)

    Dubrovin, I.V.; Budennaya, L.D.; Mizetskaya, I.B.; Sharkina, Eh.V.

    1986-01-01

    Phase equilibrium diagram of SnTe-CdSe cross-section of Sn, Cd long Te, Se ternary reciprocal system is investigated using the methods of differential thermal, X-ray phase, and microstructural analyses. Maximum length of solid solutions on the base of SnTe corresponds to approximately 14 mol.% at 1050 K and approximately 3 mol.% of CdSe at 670 K. Region of solid solutions on the base of CdSe corresponds to less than 1 mol.% of SnTe at room temperature. SnTe-CdSe cross-section is not a quasibinar one. Equilibrium is shifted to the left in the SnTe+CdSe reversible SnSe+CdTe reciprocal system

  3. The Hubble Constant from SN Refsdal

    Science.gov (United States)

    Vega-Ferrero, J.; Diego, J. M.; Miranda, V.; Bernstein, G. M.

    2018-02-01

    Hubble Space Telescope observations from 2015 December 11 detected the expected fifth counter-image of supernova (SN) Refsdal at z = 1.49. In this Letter, we compare the time-delay predictions from numerous models with the measured value derived by Kelly et al. from very early data in the light curve of the SN Refsdal and find a best value for {H}0={64}-11+9 {km} {{{s}}}-1 {{Mpc}}-1 (68% CL), in excellent agreement with predictions from cosmic microwave background and recent weak lensing data + baryon acoustic oscillations + Big Bang nucleosynthesis (from the DES Collaboration). This is the first constraint on H 0 derived from time delays between multiple-lensed SN images, and the first with a galaxy cluster lens, subject to systematic effects different from other time-delay H 0 estimates. Additional time-delay measurements from new multiply imaged SNe will allow derivation of competitive constraints on H 0.

  4. Metal-support interaction: The key factor governing activity of Pd/SnO2 catalyst for denitration of ground water

    Directory of Open Access Journals (Sweden)

    Bošković Goran C.

    2008-01-01

    Full Text Available Two mesoporous nanocristalline Pd/SnO2 catalysts were prepared by modified solgel technique differing in the pH conditions (pH = 2 and 9.5 of the synthesis of their supports. Samples achieved different activity and selectivity in water denitration reaction using hydrogen. XPS results of reduced samples indicate a strong interaction between the Pd and the Sn possibly as a result of electron shift from Sn to Pd. The solid solution of Pd2+ and SnO2 is formed by taking O from the surface of the support. In such a way some SnO2-X species may stay onto the surface and be responsible for its pronounced activity.

  5. Subgrain Rotation Behavior in Sn3.0Ag0.5Cu-Sn37Pb Solder Joints During Thermal Shock

    Science.gov (United States)

    Han, Jing; Tan, Shihai; Guo, Fu

    2018-01-01

    Ball grid array (BGA) samples were soldered on a printed circuit board with Sn37Pb solder paste to investigate the recrystallization induced by subgrain rotation during thermal shock. The composition of the solder balls was Sn3.0Ag0.5Cu-Sn37Pb, which comprised mixed solder joints. The BGA component was cross-sectioned before thermal shock. The microstructure and grain orientations were obtained by a scanning electron microscope equipped with an electron back-scattered diffraction system. Two mixed solder joints at corners of the BGA component were selected as the subjects. The results showed that recrystallization occurred at the corner of the solder joints after 200 thermal shock cycles. The recrystallized subgrains had various new grain orientations. The newly generated grain orientations were closely related to the initial grain orientations, which indicated that different subgrain rotation behaviors could occur in one mixed solder joint with the same initial grain orientation. When the misorientation angles were very small, the rotation axes were about Sn [100], [010] and [001], as shown by analyzing the misorientation angles and subgrain rotation axes, while the subgrain rotation behavior with large misorientation angles in the solder joints was much more complicated. As Pb was contained in the solder joints and the stress was concentrated on the corner of the mixed solder joints, concaves and cracks were formed. When the adjacent recrystallized subgrains were separated, and the process of the continuous recrystallization was limited.

  6. SN REFSDAL: CLASSIFICATION AS A LUMINOUS AND BLUE SN 1987A-LIKE TYPE II SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, P. L.; Filippenko, A. V.; Graham, M. L. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Brammer, G.; Strolger, L.-G.; Riess, A. G. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Selsing, J.; Hjorth, J.; Christensen, L. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Foley, R. J. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, IL 61801 (United States); Rodney, S. A. [Department of Physics and Astronomy, University of South Carolina, 712 Main St., Columbia, SC 29208 (United States); Treu, T. [University of California, Los Angeles, CA 90095 (United States); Steidel, C. C.; Strom, A.; Zitrin, A. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Schmidt, K. B.; McCully, C. [Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States); Bradač, M. [University of California, Davis, 1 Shields Avenue, Davis, CA 95616 (United States); Jha, S. W. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Graur, O., E-mail: pkelly@astro.berkeley.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States); and others

    2016-11-10

    We have acquired Hubble Space Telescope (HST) and Very Large Telescope near-infrared spectra and images of supernova (SN) Refsdal after its discovery as an Einstein cross in fall 2014. The HST light curve of SN Refsdal has a shape consistent with the distinctive, slowly rising light curves of SN 1987A-like SNe, and we find strong evidence for a broad H α P-Cygni profile and Na I D absorption in the HST grism spectrum at the redshift ( z = 1.49) of the spiral host galaxy. SNe IIn, largely powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show broad and strong H α and Na I D absorption. From the grism spectrum, we measure an H α expansion velocity consistent with those of SN 1987A-like SNe at a similar phase. The luminosity, evolution, and Gaussian profile of the H α emission of the WFC3 and X-shooter spectra, separated by ∼2.5 months in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, photometry of SN Refsdal favors bluer B - V and V - R colors and one of the largest luminosities for the assumed range of potential magnifications. The evolution of the light curve at late times will provide additional evidence about the potential existence of any substantial circumstellar material. Using MOSFIRE and X-shooter spectra, we estimate a subsolar host-galaxy metallicity (8.3 ± 0.1 dex and <8.4 dex, respectively) near the explosion site.

  7. Rational design of Sn/SnO{sub 2}/porous carbon nanocomposites as anode materials for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaojia [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Li, Xifei, E-mail: xfli2011@hotmail.com [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Center for Advanced Energy Materials and Devices, Xi’an University of Technology, Xi’an 710048 (China); Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin 300071 (China); Fan, Linlin; Yu, Zhuxin; Yan, Bo; Xiong, Dongbin; Song, Xiaosheng; Li, Shiyu [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Adair, Keegan R. [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Li, Dejun, E-mail: dejunli@mail.tjnu.edu.cn [Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Sun, Xueliang, E-mail: xsun9@uwo.ca [Nanomaterials and Energy Lab., Department of Mechanical and Materials Engineering, Western University, London, Ontario N6A 5B9 (Canada); Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China)

    2017-08-01

    Highlights: • Sn/SnO{sub 2}/porous carbon nanocomposites are rationally designed via a facile strategy. • The porous carbon mitigates the volume change and poor conductivity of Sn/SnO{sub 2}. • The nanocomposites exhibit the enhanced sodium storage performance. - Abstract: Sodium-ion batteries (SIBs) have successfully attracted considerable attention for application in energy storage, and have been proposed as an alternative to lithium ion batteries (LIBs) due to the abundance of sodium resources and low price. Sn has been deemed as a promising anode material in SIBs which holds high theoretical specific capacity of 845 mAh g{sup −1}. In this work we design nanocomposite materials consisting of porous carbon (PC) with SnO{sub 2} and Sn (Sn/SnO{sub 2}/PC) via a facile reflux method. Served as an anode material for SIBs, the Sn/SnO{sub 2}/PC nanocomposite delivers the primary discharge and charge capacities of 1148.1 and 303.0 mAh g{sup −1}, respectively. Meanwhile, it can preserve the discharge capacity approximately of 265.4 mAh g{sup −1} after 50 cycles, which is much higher than those of SnO{sub 2}/PC (138.5 mAh g{sup −1}) and PC (92.2 mAh g{sup −1}). Furthermore, the Sn/SnO{sub 2}/PC nanocomposite possesses better cycling stability with 77.8% capacity retention compared to that of SnO{sub 2}/PC (61.88%) over 50 cycles. Obviously, the Sn/SnO{sub 2}/PC composite with excellent electrochemical performance shows the great possibility of application in SIBs.

  8. Lattice doped Zn–SnO{sub 2} nanospheres: A systematic exploration of dopant ion effects on structural, optical, and enhanced gas sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Baraneedharan, P. [Nanoscience and Technology, Anna University – BIT Campus, Tiruchirappalli 620024 (India); Alternative Energy and Nanotechnology Laboratory, Indian Institute of Technology Madras, Chennai 600036 (India); Imran Hussain, S. [Nanoscience and Technology, Anna University – BIT Campus, Tiruchirappalli 620024 (India); Department of Applied Science and Technology, Anna University, Chennai 600 025 (India); Dinesh, V.P. [Nanosensor Laboratory, PSG Institute of Advanced Studies, Coimbatore 641004 (India); Siva, C. [Nanoscience and Technology, Anna University – BIT Campus, Tiruchirappalli 620024 (India); Department of Physics and Nanotechnology, SRM University, Kattankulathur 603 203 (India); Biji, P. [Nanosensor Laboratory, PSG Institute of Advanced Studies, Coimbatore 641004 (India); Sivakumar, M., E-mail: muthusiva@gmail.com [Nanoscience and Technology, Anna University – BIT Campus, Tiruchirappalli 620024 (India)

    2015-12-01

    Graphical abstract: - Highlights: • A simple, novel and surfactant free hydrothermal route to prepare SnO{sub 2} nanospheres. • A systematic investigation of growth mechanism with the assist of time dependent HR-TEM images. • Incorporation of Zn ions into SnO{sub 2} lattices clearly elucidated with XRD and XPS spectrums. • Three fold time increased response in Zn–SnO{sub 2} nanospheres when compared to undoped SnO{sub 2}. - Abstract: A surfactant-free one step hydrothermal method is reported to synthesize zinc (Zn{sup 2+}) doped SnO{sub 2} nanospheres. The structural analysis of X-ray diffraction confirms the tetragonal crystal system of the material with superior crystalline nature. The shift in diffraction peak, variation in lattice constant and disparity in particle size confirm the incorporation of Zn{sup 2+} ions to the Sn host lattices. The lattice doped structure, the disparity in morphology, size and shape by the addition of Zn{sup 2+} ions are evident from X-ray photoelectron spectroscopic and electron microscopic analysis. Significant changes in the absorption edge and the band gap with increased doping concentration were observed in UV–vis absorption spectral analysis. The formation of acceptor energy levels with the incorporation of Zn{sup 2+} ions has a significant effect on the electrical conductivity of SnO{sub 2} nanospheres. Comparative tests for gas sensors based on Zn doped SnO{sub 2} nanospheres and SnO{sub 2} nanospheres clearly show that the former exhibited excellent NO{sub 2} sensing performance. The responses of Zn{sup 2+} ions incorporated SnO{sub 2} nanospheres sensor were increased 3 fold at trace level NO{sub 2} gas concentrations ranging from 1 to 5 ppm. The excellent sensitivity, selectivity and fast response make the Zn{sup 2+} doped SnO{sub 2} nanospheres ideal for NO{sub 2} sensing.

  9. Phase diagram and structural evolution of tin/indium (Sn/In) nanosolder particles: from a non-equilibrium state to an equilibrium state.

    Science.gov (United States)

    Shu, Yang; Ando, Teiichi; Yin, Qiyue; Zhou, Guangwen; Gu, Zhiyong

    2017-08-31

    A binary system of tin/indium (Sn/In) in the form of nanoparticles was investigated for phase transitions and structural evolution at different temperatures and compositions. The Sn/In nanosolder particles in the composition range of 24-72 wt% In were synthesized by a surfactant-assisted chemical reduction method under ambient conditions. The morphology and microstructure of the as-synthesized nanoparticles were analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD). HRTEM and SAED identified InSn 4 and In, with some Sn being detected by XRD, but no In 3 Sn was observed. The differential scanning calorimetry (DSC) thermographs of the as-synthesized nanoparticles exhibited an endothermic peak at around 116 °C, which is indicative of the metastable eutectic melting of InSn 4 and In. When the nanosolders were subjected to heat treatment at 50-225 °C, the equilibrium phase In 3 Sn appeared while Sn disappeared. The equilibrium state was effectively attained at 225 °C. A Tammann plot of the DSC data of the as-synthesized nanoparticles indicated that the metastable eutectic composition is about 62% In, while that of the DSC data of the 225 °C heat-treated nanoparticles yielded a eutectic composition of 54% In, which confirmed the attainment of the equilibrium state at 225 °C. The phase boundaries estimated from the DSC data of heat-treated Sn/In nanosolder particles matched well with those in the established Sn-In equilibrium phase diagram. The phase transition behavior of Sn/In nanosolders leads to a new understanding of binary alloy particles at the nanoscale, and provides important information for their low temperature soldering processing and applications.

  10. Physical properties of some Sn-based melts

    Directory of Open Access Journals (Sweden)

    Ilinykh N.

    2011-05-01

    Full Text Available The physical properties (viscosity, density, electroresistivity and magnetic susceptibility of pure tin, copper, silver, some binary (Sn - Ag, Sn - Cu, Sn - Bi, Sn - Zn and ternary (Sn-Ag-Cu, Sn-BiAg, Sn-Bi-Zn alloys with near eutectic compositions are investigated in wide temperature ranges. The irreversible decrease of viscosity in pure tin melt is discovered at 820 °С during heating. The similar anomaly with the following hysteresis of dynamic viscosity was fixed for binary and ternary alloys but at higher temperatures – 900 °С and 950 °С respectively. For all the systems it was shown that the alloys with eutectic compositions differ significantly in their electric and magnetic properties from hypo- and hypereutectic ones. Qualitative and quantitative metallographic analysis for Sn-3.8wt.%Ag-0.7wt.%Cu samples, heated low and above characteristic temperatures, showed the influence of melt overheating on crystallization kinetics.

  11. The 7SK snRNP associates with the little elongation complex to promote snRNA gene expression.

    Science.gov (United States)

    Egloff, Sylvain; Vitali, Patrice; Tellier, Michael; Raffel, Raoul; Murphy, Shona; Kiss, Tamás

    2017-04-03

    The 7SK small nuclear RNP (snRNP), composed of the 7SK small nuclear RNA (snRNA), MePCE, and Larp7, regulates the mRNA elongation capacity of RNA polymerase II (RNAPII) through controlling the nuclear activity of positive transcription elongation factor b (P-TEFb). Here, we demonstrate that the human 7SK snRNP also functions as a canonical transcription factor that, in collaboration with the little elongation complex (LEC) comprising ELL, Ice1, Ice2, and ZC3H8, promotes transcription of RNAPII-specific spliceosomal snRNA and small nucleolar RNA (snoRNA) genes. The 7SK snRNA specifically associates with a fraction of RNAPII hyperphosphorylated at Ser5 and Ser7, which is a hallmark of RNAPII engaged in snRNA synthesis. Chromatin immunoprecipitation (ChIP) and chromatin isolation by RNA purification (ChIRP) experiments revealed enrichments for all components of the 7SK snRNP on RNAPII-specific sn/snoRNA genes. Depletion of 7SK snRNA or Larp7 disrupts LEC integrity, inhibits RNAPII recruitment to RNAPII-specific sn/snoRNA genes, and reduces nascent snRNA and snoRNA synthesis. Thus, through controlling both mRNA elongation and sn/snoRNA synthesis, the 7SK snRNP is a key regulator of nuclear RNA production by RNAPII. © 2017 The Authors.

  12. Synthesis of trans-4,5-epoxy-(E)-2-decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization.

    Science.gov (United States)

    Lin, J; Fay, L B; Welti, D H; Blank, I

    1999-10-01

    The volatile compound trans-4,5-epoxy-(E)-2-decenal (1) was synthesized in two steps with good overall yields. The newly developed method is based on trans-epoxidation of (E)-2-octenal with alkaline hydrogen peroxide followed by a Wittig-type chain elongation with the ylide formylmethylene triphenylphosphorane. For the synthesis of [4,5-2H2]-trans-4,5-epoxy-(E)-2-decenal (d-1), [2,3-2H2]-(E)-2-octenal was prepared by reduction of 2-octyn-1-ol with lithium aluminum deuteride and subsequent oxidation of [2,3-2H2]-(E)-2-octen-1-ol with manganese oxide. Compound d1 was used as internal standard for the quantification of 1 by isotope dilution assay. Among various mass spectrometry (MS) ionization techniques tested, negative chemical ionization with ammonia as reagent gas gave best results with respect to both sensitivity and selectivity. The detection limit was found to be at about 1 pg of the analyte introduced into the gas chromatography-MS system.

  13. Neutron rich nuclei around 132Sn

    International Nuclear Information System (INIS)

    Bhattacharya, Sarmishtha

    2016-01-01

    The neutron rich nuclei with few particles or holes in 132 Sn have various experimental and theoretical interest to understand the evolution of nuclear structure around the doubly magic shell closure Z=50 and N=82. Some of the exotic neutron rich nuclei in this mass region are situated near waiting points in the r-process path and are of special astrophysical interest. Neutron rich nuclei near 132 Sn have been studied using fission fragment spectroscopy. The lifetime of low lying isomeric states have been precisely measured and the beta decay from the ground and isomeric states have been characterized using gamma-ray spectroscopy

  14. Study of superconducting Nb3Sn coils

    International Nuclear Information System (INIS)

    Vivet, B.

    1963-01-01

    Composite superconducting Nb 3 Sn wires with a diameter of 0.5 mm and a length of about 100 m were made, and Hc-Ic diagrams were plotted up to fields of 80 kgauss for short lengths. Two solenoids producing fields of about 20 kgauss were studied. Nb 3 Sn solenoids, as opposed to those of Nb-Zr or Nb-Ti, appear to have a predictable behavior. Solenoids with less insulation produced stronger fields than heavily insulated solenoids. (author) [fr

  15. Aluminium stabilized Nb$-3$/Sn superconductors

    International Nuclear Information System (INIS)

    Thoener, M.; Krauth, H.; Rudolph, J.; Szulczyk, A.

    1988-01-01

    Composite superconductors made of reacted Nb 3 Sn stabilized with high purity Al were produced. Two methods were tested. The first involved soft soldering a Cu clad aluminum tape to the Nb 3 Sn conductor. In the second method the conductor, cable or monolith, was coextruded with the aluminum. Results obtained from using both methods indicated that mechanically reinforcing materials can be easily introduced into superconductors. Tests were conducted to determine magnetoresistance, electric contact resistance, yield strength, Young modulus, critical current, and other properties of the composites. Strengthening with Duratherm during coextrusion was also evaluated

  16. PbSnTe injection lasers

    International Nuclear Information System (INIS)

    Oron, M.

    1982-03-01

    Carrier confined homostructure PbSnTe lasers were developed and investigated. In this laser structure good electrical and optical confinement can be achieved by a suitable carrier concentration profile. The advantage of these lasers over PbSnTe heterostructure lasers is the perfect lattice matching between the various layers of the structure. The desired carrier concentration profile was achieved by the growth of several epitaxial layers by the LPE method on a suitable substrate. The performance of these lasers was compared with that of previous homostructure and double heterostructure lasers. (H.K.)

  17. Electronic structure and electric fields gradients of crystalline Sn(II) and Sn(IV) compounds

    International Nuclear Information System (INIS)

    Terra, J.; Guenzburger, D.

    1991-01-01

    The electronic structures of clusters representing crystalline compounds of Sn(II) and Sn(IV) were investigated, employing the first-principles Discrete Variational method and Local Density theory. Densities of states and related parameters were obtained and compared with experimental measurements and with results from band structure calculations. Effects of cluster size and of cluster truncated bonds are discussed. Electric field gradients at the Sn nucleus were calculated; results are analysed in terms of charge distribution and chemical bonding in the crystals. (author)

  18. Effect of Sn doping on the room temperature magnetodielectric properties of yttrium iron garnet

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhizhi; Chen, Fu; Li, Junnan; Feng, Zekun; Nie, Yan, E-mail: nieyan@hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan (China)

    2015-10-21

    The structures, magnetic properties, permittivity spectra, and magnetodielectric (MD) effects of polycrystalline Y{sub 3}Fe{sub 5−x}Sn{sub x}O{sub 12} compounds prepared by solid state reactions were systematically investigated. The substitution of Sn{sup 4+} leads to lattice expansion and the donation of excess electrons in ceramics, which affects the concentration of Fe{sup 2+}, space charge, and electric dipole. As a result, as the amount of Sn dopant increases, so does saturation magnetization and permittivity in the low frequency band. The MD coefficient ([ε{sub r}(H) − ε{sub r}(0)]/ε{sub r}(0)) of lightly doped samples (x ≤ 0.05) is negative in the entire frequency band, reaching −2.3% at 350 MHz and 0.6 T for Y{sub 3}Fe{sub 4.95}Sn{sub 0.05}O{sub 12} ceramics. The MD coefficient of heavily doped samples (x > 0.05) is positive in the low frequency band, reaching 0.83% at 10 MHz and 0.6 T for Y{sub 3}Fe{sub 4.925}Sn{sub 0.075}O{sub 12} ceramics, and then decreasing with the increasing frequency, gradually becoming negative in the high frequency band. A detailed explanation is provided based on the origin of permittivity. This study provides a new methodology according to which the MD materials may be designed in order to satisfy the requirements of engineering applications.

  19. Tin (Sn) for enhancing performance in silicon CMOS

    KAUST Repository

    Hussain, Aftab M.; Fahad, Hossain M.; Singh, Nirpendra; Sevilla, Galo T.; Schwingenschlö gl, Udo; Hussain, Muhammad Mustafa

    2013-01-01

    We study a group IV element: tin (Sn) by integrating it into silicon lattice, to enhance the performance of silicon CMOS. We have evaluated the electrical properties of the SiSn lattice by performing simulations using First-principle studies, followed by experimental device fabrication and characterization. We fabricated high-κ/metal gate based Metal-Oxide-Semiconductor capacitors (MOSCAPs) using SiSn as channel material to study the impact of Sn integration into silicon. © 2013 IEEE.

  20. Tin (Sn) for enhancing performance in silicon CMOS

    KAUST Repository

    Hussain, Aftab M.

    2013-10-01

    We study a group IV element: tin (Sn) by integrating it into silicon lattice, to enhance the performance of silicon CMOS. We have evaluated the electrical properties of the SiSn lattice by performing simulations using First-principle studies, followed by experimental device fabrication and characterization. We fabricated high-κ/metal gate based Metal-Oxide-Semiconductor capacitors (MOSCAPs) using SiSn as channel material to study the impact of Sn integration into silicon. © 2013 IEEE.

  1. Gas sensing properties of zinc stannate (Zn{sub 2}SnO{sub 4}) nanowires prepared by carbon assisted thermal evaporation process

    Energy Technology Data Exchange (ETDEWEB)

    Tharsika, T., E-mail: tharsika@siswa.um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Akbar, S.A., E-mail: akbar.1@osu.edu [Center for Industrial Sensors and Measurements (CISM), Department of Materials Science and Engineering, Ohio State University, 2041 College Road, Columbus, OH 43210 (United States); Sabri, M.F.M., E-mail: faizul@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Wong, Y.H., E-mail: yhwong@um.edu.my [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-01-05

    Highlights: • Zn{sub 2}SnO{sub 4} nanowires are grown on Au/alumina substrate by a carbon assisted thermal evaporation process. • Optimum growth conditions for Zn{sub 2}SnO{sub 4} nanowires are determined. • Ethanol gas is selectively sensed with high sensitivity. - Abstract: Zn{sub 2}SnO{sub 4} nanowires are successfully synthesized by a carbon assisted thermal evaporation process with the help of a gold catalyst under ambient pressure. The as-synthesized nanowires are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) equipped with an energy dispersive X-ray spectroscopy (EDS). The XRD patterns and elemental mapping via TEM–EDS clearly indicate that the nanowires are Zn{sub 2}SnO{sub 4} with face centered spinel structure. HRTEM image confirms that Zn{sub 2}SnO{sub 4} nanowires are single crystalline with an interplanar spacing of 0.26 nm, which is ascribed to the d-spacing of (3 1 1) planes of Zn{sub 2}SnO{sub 4}. The optimum processing condition and a possible formation mechanism of these Zn{sub 2}SnO{sub 4} nanowires are discussed. Additionally, sensor performance of Zn{sub 2}SnO{sub 4} nanowires based sensor is studied for various test gases such as ethanol, methane and hydrogen. The results reveal that Zn{sub 2}SnO{sub 4} nanowires exhibit excellent sensitivity and selectivity toward ethanol with quick response and recovery times. The response of the Zn{sub 2}SnO{sub 4} nanowires based sensors to 50 ppm ethanol at an optimum operating temperature of 500 °C is about 21.6 with response and recovery times of about 116 s and 182 s, respectively.

  2. SiSn diodes: Theoretical analysis and experimental verification

    KAUST Repository

    Hussain, Aftab M.; Wehbe, Nimer; Hussain, Muhammad Mustafa

    2015-01-01

    We report a theoretical analysis and experimental verification of change in band gap of silicon lattice due to the incorporation of tin (Sn). We formed SiSn ultra-thin film on the top surface of a 4 in. silicon wafer using thermal diffusion of Sn

  3. Summary of George Mason University SN1987A workshop

    International Nuclear Information System (INIS)

    van den Bergh, S.

    1990-01-01

    The author summaries studies of SN 1987A. This discussion focuses on how theories of core collapse in supernovae have been confirmed by observations of neutrinos produced by SN1987A and observations of the exponential tail of the light curve of SN1987A give strong support to the prediction that this phase of supernova light curves is powered by 56 Co decay

  4. The cysteine rich necrotrophic effector SnTox1 produced by Stagonospora nodorum triggers susceptibility of wheat lines harboring Snn1.

    Directory of Open Access Journals (Sweden)

    Zhaohui Liu

    2012-01-01

    Full Text Available The wheat pathogen Stagonospora nodorum produces multiple necrotrophic effectors (also called host-selective toxins that promote disease by interacting with corresponding host sensitivity gene products. SnTox1 was the first necrotrophic effector identified in S. nodorum, and was shown to induce necrosis on wheat lines carrying Snn1. Here, we report the molecular cloning and validation of SnTox1 as well as the preliminary characterization of the mechanism underlying the SnTox1-Snn1 interaction which leads to susceptibility. SnTox1 was identified using bioinformatics tools and verified by heterologous expression in Pichia pastoris. SnTox1 encodes a 117 amino acid protein with the first 17 amino acids predicted as a signal peptide, and strikingly, the mature protein contains 16 cysteine residues, a common feature for some avirulence effectors. The transformation of SnTox1 into an avirulent S. nodorum isolate was sufficient to make the strain pathogenic. Additionally, the deletion of SnTox1 in virulent isolates rendered the SnTox1 mutated strains avirulent on the Snn1 differential wheat line. SnTox1 was present in 85% of a global collection of S. nodorum isolates. We identified a total of 11 protein isoforms and found evidence for strong diversifying selection operating on SnTox1. The SnTox1-Snn1 interaction results in an oxidative burst, DNA laddering, and pathogenesis related (PR gene expression, all hallmarks of a defense response. In the absence of light, the development of SnTox1-induced necrosis and disease symptoms were completely blocked. By comparing the infection processes of a GFP-tagged avirulent isolate and the same isolate transformed with SnTox1, we conclude that SnTox1 may play a critical role during fungal penetration. This research further demonstrates that necrotrophic fungal pathogens utilize small effector proteins to exploit plant resistance pathways for their colonization, which provides important insights into the molecular

  5. CONSTRUÇÕES BINOMINAIS DO TIPO SN1 DE SN2

    Directory of Open Access Journals (Sweden)

    Karen Sampaio Braga Alonso

    2017-04-01

    Full Text Available Este artigo tem por objetivo investigar a flutuação de sentido quantidade-qualidade licenciada pelo uso de construtos binominais do tipo SN1 de SN2, como xícara de chá, no Português do Brasil.A pesquisa é baseada na perspectiva teórica da Linguística Funcional Centrada no Uso (BYBEE, 2010; BARLOW E KEMMER, 2000; TOMASELLO, 2003, TRAUGOTT, 2008 e busca descrever as propriedades morfossintáticas, semântico-pragmáticas e cognitivas dos usos das construções que favorecem uma leitura ora qualitativa ora quantitativa, no que se refere à relação entre SN1 e SN2.

  6. Properties of second phase (BaSnO3, Sn) added-YBCO thick films

    International Nuclear Information System (INIS)

    Ban, E.; Matsuoka, Y.

    1997-01-01

    The improvement of the critical current density J c of YBCO thick films has been attempted by adding BaSnO 3 powder and ultrafine Sn particles, whose diameter is about 2 μm and 7 x 10 -2 μm, respectively. It was found that the addition of a small amount of these particles was effective for the enhancement of J c of thick films prepared by a liquid-phase processing method. The 1 wt.% BaSnO 3 films fired at T s =1040-1060 C and the 3 wt.% Sn films (T s =1030-1060 C) showed J c values (77 K, 0 T) of about 2.1-2.4 x 10 3 Acm -2 and 3.1-3.5 x 10 3 Acm -2 , respectively, as compared to 2.0 x 10 3 Acm -2 for the undoped films. (orig.)

  7. The electrocatalytic reduction of nitrate in water on Pd/Sn-modified activated carbon fiber electrode.

    Science.gov (United States)

    Wang, Ying; Qu, Jiuhui; Wu, Rongcheng; Lei, Pengju

    2006-03-01

    The Pd/Sn-modified activated carbon fiber (ACF) electrodes were successfully prepared by the impregnation of Pd2+ and Sn2+ ions onto ACF, and their electrocatalytic reduction capacity for nitrate ions in water was evaluated in a batch experiment. The electrode was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and temperature programmed reduction (TPR). The capacity for nitrate reduction depending on Sn content on the electrode and the pH of electrolyte was discussed at length. The results showed that at an applied current density of 1.11 mA cm(-2), nitrate ions in water (solution volume: 400 mL) were reduced from 110 to 3.4 mg L(-1) after 240 min with consecutive change of intermediate nitrite. Ammonium ions and nitrogen were formed as the main final products. The amount of other possible gaseous products (including NO and N2O) was trace. With the increase of Sn content on the Pd/Sn-modified ACF electrode, the activity for nitrate reduction went up to reach a maximum (at Pd/Sn = 4) and then decreased, while the selectivity to N2 was depressed. Higher pH value of electrolyte exhibited more suppression effect on the reduction of nitrite than that of nitrate. However, no significant influence on the final ammonia formation was observed. Additionally, Cu ion in water was found to cover the active sites of the electrode to make the electrode deactivated.

  8. Fabrication of novel SnO2 nanofibers bundle and their optical properties

    International Nuclear Information System (INIS)

    Butt, Faheem K.; Cao, Chuanbao; Khan, Waheed S.; Ali, Zulfiqar; Mahmood, Tariq; Ahmed, R.; Hussain, Sajad; Nabi, Ghulam

    2012-01-01

    Here we report on the synthesis of novel SnO 2 nanofibers bundle (NFB) by using ball milled Fe powders via chemical vapor deposition (CVD). The reaction was carried out in a horizontal tube furnace (HTF) at 1100 °C under Ar flow. The as prepared product was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy and selected area electron diffraction (SAED). The microscopy analysis reveals the existence of tubular structure that might be formed by the accumulation of nanofibers. The Raman spectrum reveals that the product is rutile SnO 2 with additional peaks ascribed to defects or oxygen vacancies. Room temperature Photoluminescence (PL) spectrum exhibits three emission bands at 369, 450 and 466.6 nm. Using optical absorbance data, a direct optical bandgap of 3.68 eV was calculated. -- Graphical abstract: Novel SnO 2 nanofibers bundle (NFB) fabricated via CVD method. Field emission scanning electron microscopy image of novel SnO 2 NFB and their room temperature PL emission. Highlights: ► Synthesis of novel SnO 2 nanofibers bundle at 1100 °C under partial flow of Ar gas. ► A VLS mechanism is proposed for the formation of SnO 2 nanofibers. ► The PL spectrum exhibits three emission bands at 369, 450 and 466.6 nm. ► A direct optical bandgap of 3.68 eV was calculated.

  9. Metal organic frameworks-derived sensing material of SnO2/NiO composites for detection of triethylamine

    Science.gov (United States)

    Bai, Shouli; Liu, Chengyao; Luo, Ruixian; Chen, Aifan

    2018-04-01

    The SnO2/NiO composites were synthesized by hydrothermal followed by calcination using metal-organic framework (MOF) consisting of the ligand of p-benzene-dicarboxylic acid (PTA) and the Sn and Ni center ions as sacrificial templates. The structure and morphology of Sn/Ni-based MOF and SnO2/NiO composites were characterized by XRD, SEM, TEM, FT-IR, TG, XPS and Brunauer-Emmett-Teller analysis. Sensing experiments reveal that the SnO2/NiO composite with the molar ratio of 9:1 not only exhibits the highest response of 14.03 that is 3 times higher than pristine SnO2 to triethylamine at 70 °C, but also shows good selectivity. Such excellent performance is attributed to the MOF-driven strategy and the formation of p-n heterojunctions, because the metal ions can be highly dispersed and separated in the MOFs and can prevent the metal ions aggregation during the MOF decomposition process. The work is a novel route for synthesis of gas sensing material.

  10. Preparation and characterization of Ti/SnO2-Sb electrode with copper nanorods for AR 73 removal

    International Nuclear Information System (INIS)

    Xu, Li; Li, Ming; Xu, Wei

    2015-01-01

    Novel Ti/Cu-NRs/SnO 2 -Sb electrode modified by copper (Cu) nanorods was fabricated through anodic aluminum oxide (AAO) template assisted electrochemical deposition (ECD) for wastewater treatment. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and electrochemical methods such as linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the surface morphology, crystal structure and electrochemical performance of the electrodes. Acid dye AR 73 was selected as target pollutants to investigate the electro-catalyst behavior, and UV/vis spectroscopy was used to monitor the concentration changes with time. The results indicated that the presence of Cu nanorods on the Ti substrate promoted the electrodes' property obviously. Ti/Cu-NRs/SnO 2 -Sb anode possessed smaller charge transfer resistance and longer service life than Ti/SnO 2 -Sb anode. The oxygen evolution potential (OEP) of Ti/Cu-NRs/SnO 2 -Sb electrodes reach 2.17 V (vs. Ag/AgCl). Removal of pollutants and reaction rate were all promoted due to the introduction of Cu nanorods in the process of AR 73 decomposing with Ti/Cu-NRs/SnO 2 -Sb electrodes. And specific energy consumption also reduced remarkably. Our study has shown that the fabricated Ti/Cu-NRs/SnO 2 -Sb electrodes are very promising for the electrochemical treatment of wastewater

  11. Phase behaviour, thermal expansion and compressibility of SnMo 2 O 8

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Luiza R.; Gallington, Leighanne C.; Wilkinson, Angus P.; Evans, John S.O. (Durham); (GIT)

    2018-02-01

    The phase behaviour and thermoelastic properties of SnMo2O8, derived from variable temperature and pressure synchrotron powder diffraction data, are reported. SnMo2O8 is a member of the AM2O8 family of negative thermal expansion (NTE) materials, but unexpectedly, has positive thermal expansion. Over the P-T space explored (298–513 K, ambient to 310 MPa) four different forms of SnMo2O8 are observed: α, β, γ and γ'. The γ to β transition is temperature-, pressure-, and time-dependent. SnMo2O8 is a much softer material (α and γ form have BT = 29 and 26 GPa at 298 K) than other members of the AM2O8 family. Counter-intuitively, its high temperature β phase becomes stiffer with increasing temperature (BT ~36 GPa at 490 K). The pressure dependence of the thermal expansion for each phase is reported.

  12. Primordial black holes survive SN lensing constraints

    Science.gov (United States)

    García-Bellido, Juan; Clesse, Sébastien; Fleury, Pierre

    2018-06-01

    It has been claimed in [arxiv:1712.02240] that massive primordial black holes (PBH) cannot constitute all of the dark matter (DM), because their gravitational-lensing imprint on the Hubble diagram of type Ia supernovae (SN) would be incompatible with present observations. In this note, we critically review those constraints and find several caveats on the analysis. First of all, the constraints on the fraction α of PBH in matter seem to be driven by a very restrictive choice of priors on the cosmological parameters. In particular, the degeneracy between Ωm and α was ignored and thus, by fixing Ωm, transferred the constraining power of SN magnitudes to α. Furthermore, by considering more realistic physical sizes for the type-Ia supernovae, we find an effect on the SN lensing magnification distribution that leads to significantly looser constraints. Moreover, considering a wide mass spectrum of PBH, such as a lognormal distribution, further softens the constraints from SN lensing. Finally, we find that the fraction of PBH that could constitute DM today is bounded by fPBH < 1 . 09(1 . 38) , for JLA (Union 2.1) catalogs, and thus it is perfectly compatible with an all-PBH dark matter scenario in the LIGO band.

  13. Multiepoch Spectropolarimetry of SN 2011fe

    Energy Technology Data Exchange (ETDEWEB)

    Milne, Peter A.; Williams, G. Grant; Smith, Paul S.; Smith, Nathan; Jannuzi, Buell T.; Green, E. M. [University of Arizona, Steward Observatory, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Porter, Amber; Leising, Mark D. [118 Kinard Laboratory, Clemson University, Clemson, SC 29634 (United States)

    2017-01-20

    We present multiple spectropolarimetric observations of the nearby Type Ia supernova (SN) 2011fe in M101, obtained before, during, and after the time of maximum apparent visual brightness. The excellent time coverage of our spectropolarimetry has allowed better monitoring of the evolution of polarization features than is typical, which has allowed us new insight into the nature of normal SNe Ia. SN 2011fe exhibits time-dependent polarization in both the continuum and strong absorption lines. At early epochs, red wavelengths exhibit a degree of continuum polarization of up to 0.4%, likely indicative of a mild asymmetry in the electron-scattering photosphere. This behavior is more common in subluminous SNe Ia than in normal events, such as SN 2011fe. The degree of polarization across a collection of absorption lines varies dramatically from epoch to epoch. During the earliest epoch, a λ 4600–5000 Å complex of absorption lines shows enhanced polarization at a different position angle than the continuum. We explore the origin of these features, presenting a few possible interpretations, without arriving at a single favored ion. During two epochs near maximum, the dominant polarization feature is associated with the Si ii λ 6355 Å absorption line. This is common for SNe Ia, but for SN 2011fe the polarization of this feature increases after maximum light, whereas for other SNe Ia, that polarization feature was strongest before maximum light.

  14. Production and application of Sn-117m

    International Nuclear Information System (INIS)

    Vucina, J.; Nikolic, N.; Orlic, M.

    2005-01-01

    For targeted therapy in nuclear medicine, besides the usually used, like 32 P, 89 Sr, 131 I, 186,188 Re, new radioisotopes are intensively investigated. Particular interest is devoted to 117m Sn. It decays by isomeric transition with the emission of low energy conversion electrons and short range. Their potent lethality, due to high LET, particularly when the emitter is located inside the cell, on or near nucleus, is well known. The accompanying gamma rays (Eγ = 159 keV) are also suitable for detection. At present, the specific activity which can be achieved in nuclear reactors is is sufficient for the production of agents for bone palliation. The best results so far were achieved with 117m Sn(IV)-DTPA. It is expected that the use of this radioisotope will increase when a method of its production in the no-carrier form will be developed. In the paper the production of 117m Sn and 117m Sn radiopharmaceuticals is briefly reviewed. (author) [sr

  15. Multiepoch Spectropolarimetry of SN 2011fe

    International Nuclear Information System (INIS)

    Milne, Peter A.; Williams, G. Grant; Smith, Paul S.; Smith, Nathan; Jannuzi, Buell T.; Green, E. M.; Porter, Amber; Leising, Mark D.

    2017-01-01

    We present multiple spectropolarimetric observations of the nearby Type Ia supernova (SN) 2011fe in M101, obtained before, during, and after the time of maximum apparent visual brightness. The excellent time coverage of our spectropolarimetry has allowed better monitoring of the evolution of polarization features than is typical, which has allowed us new insight into the nature of normal SNe Ia. SN 2011fe exhibits time-dependent polarization in both the continuum and strong absorption lines. At early epochs, red wavelengths exhibit a degree of continuum polarization of up to 0.4%, likely indicative of a mild asymmetry in the electron-scattering photosphere. This behavior is more common in subluminous SNe Ia than in normal events, such as SN 2011fe. The degree of polarization across a collection of absorption lines varies dramatically from epoch to epoch. During the earliest epoch, a λ 4600–5000 Å complex of absorption lines shows enhanced polarization at a different position angle than the continuum. We explore the origin of these features, presenting a few possible interpretations, without arriving at a single favored ion. During two epochs near maximum, the dominant polarization feature is associated with the Si ii λ 6355 Å absorption line. This is common for SNe Ia, but for SN 2011fe the polarization of this feature increases after maximum light, whereas for other SNe Ia, that polarization feature was strongest before maximum light.

  16. Discovery of Ten ASAS-SN Supernovae

    Science.gov (United States)

    Nicholls, B.; Brimacombe, J.; Kiyota, S.; Stone, G.; Cruz, I.; Trappett, D.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.

    2018-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the "Leavitt" telescope in Fort Davis, Texas, the "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  17. Discovery of 11 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Fernandez, J. M.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Nicholls, B.

    2018-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the "Leavitt" telescope in Fort Davis, Texas, the "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  18. Study of Sn100-xMnx amorphous system by 119Sn Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Drago, V.

    1986-01-01

    Thin films of Sn 100-x Mn x amorphous alloys with large range of concentrations were procedure by vapor condensation technique on substrates at temperatures near to liquid helium. The magnetic and paramagnetic hyperfine spectra, and the ordering temperatures were measured by 119 Sn Moessbauer effect. The electrical resistivity was used for characterizing the amorphous state. All the measurements were done 'in situ'. A magnetic phase diagram is proposed. (M.C.K.) [pt

  19. Massive stars dying alone: Extremely remote environments of SN2009ip and SN2010jp

    Science.gov (United States)

    Smith, Nathan

    2014-10-01

    We propose an imaging study of the astonishingly remote environments of two recent supernovae (SNe): SN2009ip and SN2010jp. Both were unusual Type IIn explosions that crashed into dense circumstellar material (CSM) ejected by the star shortly before explosion. The favored progenitors of these SNe are very massive luminous blue variable (LBV) stars. In fact, SN2009ip presents an extraordinay case where the LBV-like progenitor was actually detected directly in archival HST data, and where we obtained spectra and photometry for numerous pre-SN eruptions. No other SN has this treasure trove of detailed information about the progenitor (not even SN1987A). SN2010jp represents a possible collapsar-powered event, since it showed evidence of a fast bipolar jet in spectra and a low 56Ni mass; this would be an analog of the black-hole forming explosions that cause gamma ray bursts, but where the relativistic jet is damped by a residual H envelope on the star. In both cases, the only viable models for these SNe involve extremely massive (initial masses of 40-100 Msun) progenitor stars. This seems at odds with their extremely remote environments in the far outskirts of their host galaxies, with no detected evidence for an underlying massive star population in ground-based data (nor in the single shallow WFPC2/F606W image of SN2009ip). Here we propose deep UV HST images to search for any mid/late O-type stars nearby, deep red images to detect any red supergiants, and an H-alpha image to search for any evidence of ongoing star formation in the vicinity. These observations will place important and demanding constraints on the initial masses and ages of these progenitors.

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

    Science.gov (United States)

    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

  1. 70 °C synthesis of high-Sn content (25%) GeSn on insulator by Sn-induced crystallization of amorphous Ge

    Energy Technology Data Exchange (ETDEWEB)

    Toko, K., E-mail: toko@bk.tsukuba.ac.jp; Oya, N.; Suemasu, T. [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Saitoh, N.; Yoshizawa, N. [Electron Microscope Facility, TIA, AIST, 16-1 Onogawa, Tsukuba 305-8569 (Japan)

    2015-02-23

    Polycrystalline GeSn thin films are fabricated on insulating substrates at low temperatures by using Sn-induced crystallization of amorphous Ge (a-Ge). The Sn layer stacked on the a-Ge layer (100-nm thickness each) had two roles: lowering the crystallization temperature of a-Ge and composing GeSn. Slow annealing at an extremely low temperature of 70 °C allowed for a large-grained (350 nm) GeSn layer with a lattice constant of 0.590 nm, corresponding to a Sn composition exceeding 25%. The present investigation paves the way for advanced electronic optical devices integrated on a flexible plastic substrate as well as on a Si platform.

  2. SN 2013fs and SN 2013fr: exploring the circumstellar-material diversity in Type II supernovae

    Science.gov (United States)

    Bullivant, Christopher; Smith, Nathan; Williams, G. Grant; Mauerhan, Jon C.; Andrews, Jennifer E.; Fong, Wen-Fai; Bilinski, Christopher; Kilpatrick, Charles D.; Milne, Peter A.; Fox, Ori D.; Cenko, S. Bradley; Filippenko, Alexei V.; Zheng, WeiKang; Kelly, Patrick L.; Clubb, Kelsey I.

    2018-05-01

    We present photometry and spectroscopy of SN 2013fs and SN 2013fr in the first ˜100 d post-explosion. Both objects showed transient, relatively narrow H α emission lines characteristic of SNe IIn, but later resembled normal SNe II-P or SNe II-L, indicative of fleeting interaction with circumstellar material (CSM). SN 2013fs was discovered within 8 h of explosion; one of the earliest SNe discovered thus far. Its light curve exhibits a plateau, with spectra revealing strong CSM interaction at early times. It is a less luminous version of the transitional SN IIn PTF11iqb, further demonstrating a continuum of CSM interaction intensity between SNe II-P and SNe IIn. It requires dense CSM within 6.5 × 1014 cm of the progenitor, from a phase of advanced pre-SN mass loss beginning shortly before explosion. Spectropolarimetry of SN 2013fs shows little continuum polarization (˜0.5 per cent, consistent with zero), but noticeable line polarization during the plateau phase. SN 2013fr morphed from an SN IIn at early times to an SN II-L. After the first epoch, its narrow lines probably arose from host-galaxy emission, but the bright, narrow H α emission at early times may be intrinsic to the SN. As for SN 2013fs, this would point to a short-lived phase of strong CSM interaction if proven to be intrinsic, suggesting a continuum between SNe IIn and SNe II-L. It is a low-velocity SN II-L like SN 2009kr, but more luminous. SN 2013fr also developed an infrared excess at later times, due to warm CSM dust that requires a more sustained phase of strong pre-SN mass loss.

  3. Diffusion couple studies of the Ni-Bi-Sn system

    Directory of Open Access Journals (Sweden)

    Vassilev G.

    2012-01-01

    Full Text Available Investigations of Ni-Bi-Sn system were performed in order to inquire the phase diagram and to assess some diffusion kinetic parameters. For this purpose diffusion couples consisting of solid nickel (preliminary electroplated with tin and liquid Bi-Sn phase were annealed at 370 °C. Three compositions (0.8, 0.6 and 0.4 mole fractions Sn of the Bi-Sn melts were chosen. Annealing times from 24 to 216 h were applied. The phase and chemical compositions of the contact zone were determined by means of electron scanning microscope. It was confirmed that the diffusion layers consist mainly of Ni3Sn4 but other intermetallic phases grow as well. For the first time metastable Ni-Sn phases as NiSn and NiSn8 (NiSn9 were observed in metallurgical alloys (i.e. not in electroplated samples. The existence of a ternary compound previously reported in the literature was confirmed. More than one ternary Ni-Bi-Sn compounds might possibly be admitted. A growth coefficient of (2.29 ± 0.02 x 10-15 m2 s-1 was obtained. It was found that the apparent activation energy for diffusion layers growth (18 ± 8 kJ mol-1 is inferior to that one assessed at growth from solid state Bi-Sn mixtures (88 ± 12 kJ mol-1.

  4. Local atomic structure inheritance in Ag50Sn50 melt

    International Nuclear Information System (INIS)

    Bai, Yanwen; Bian, Xiufang; Qin, Jingyu; Hu, Lina; Yang, Jianfei; Zhang, Kai; Zhao, Xiaolin; Yang, Chuncheng; Zhang, Shuo; Huang, Yuying

    2014-01-01

    Local structure inheritance signatures were observed during the alloying process of the Ag 50 Sn 50 melt, using high-temperature X-ray diffraction and ab initio molecular dynamics simulations. The coordination number N m around Ag atom is similar in the alloy and in pure Ag melts (N m  ∼ 10), while, during the alloying process, the local structure around Sn atoms rearranges. Sn-Sn covalent bonds were substituted by Ag-Sn chemical bonds, and the total coordination number around Sn increases by about 70% as compared with those in the pure Sn melt. Changes in the electronic structure of the alloy have been studied by Ag and Sn K-edge X-ray absorption spectroscopy, as well as by calculations of the partial density of states. We propose that a leading mechanism for local structure inheritance in Ag 50 Sn 50 is due to s-p dehybridization of Sn and to the interplay between Sn-s and Ag-d electrons

  5. Effects of annealing on evaporated SnS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sakrani, Samsudi; Ismail, Bakar [Universiti Teknologi Malaysia, Skudai, Johor Bahru (Malaysia). Dept. of Physics

    1994-12-31

    The effects of annealing of evaporated tin sulphide thin films (SnS) are described. The films were initially deposited onto glass substrate, followed by annealing in an encapsulated carbon block under the running argon gas at 310 degree Celsius. Short time annealing of the films results in a slight change of the compositions to a mix SnS/SnS sub 2 compound, and the tendency of increasing SnS sub 2 formation was observed on the films annealed for longer periods up to 20 hours. X-ray results showed the transformation of SnS peaks (040) and (080) to predominantly SnS sub 2 peaks - (001), (100), (101), and (110). The associated absorption coefficients measured on the films were found to be greater than 10 sup 5 cm sup -1, with indication of higher photon energy leading to the formation of SnS sub 2 compound.

  6. Effects of annealing on evaporated SnS thin films

    International Nuclear Information System (INIS)

    Samsudi Sakrani; Bakar Ismail

    1994-01-01

    The effects of annealing of evaporated tin sulphide thin films (SnS) are described. The films were initially deposited onto glass substrate, followed by annealing in an encapsulated carbon block under the running argon gas at 310 degree Celsius. Short time annealing of the films results in a slight change of the compositions to a mix SnS/SnS sub 2 compound, and the tendency of increasing SnS sub 2 formation was observed on the films annealed for longer periods up to 20 hours. X-ray results showed the transformation of SnS peaks (040) and (080) to predominantly SnS sub 2 peaks - (001), (100), (101), and (110). The associated absorption coefficients measured on the films were found to be greater than 10 sup 5 cm sup -1, with indication of higher photon energy leading to the formation of SnS sub 2 compound

  7. Polymer-SnO2 composite membranes

    DEFF Research Database (Denmark)

    Nørgaard, Casper Frydendal; Skou, Eivind Morten

    . This work utilizes the latter approach and makes use of particles of tin dioxide (SnO2). Polymer-SnO2 composite membranes were successfully prepared using an ion-exchange method. SnO2 was incorporated into membranes by ion-exchange in solutions of SnCl2 ∙ 2 H2O in methanol, followed by oxidation to SnO2...... in air. The content of SnO2 proved controllable by adjusting the concentration of the ion-exchange solution. The prepared nanocomposite membranes were characterized by powder XRD, 119Sn MAS NMR, electrochemical impedance spectroscopy, water uptake and tensile stress-strain measurements. For Nafion 117...

  8. Hydrolysis of bis(dimethylamido)tin to tin (II) oxyhydroxide and its selective transformation into tin (II) or tin (IV) oxide

    KAUST Repository

    Khanderi, Jayaprakash

    2015-03-01

    Sn6O4(OH)4, a hydrolysis product of Sn(NMe2)2, is transformed to tin (II) or tin (IV) oxide by solid and solution phase processing. Tin (II) oxide is formed by heating Sn6O4(OH)4 at ≤200 °C in air or under inert atmosphere. Tin (IV) oxide nanoparticles are formed in the presence of a carboxylic acid and base in air at room temperature. IR spectroscopy, Raman spectroscopy, thermogravimetry (coupled with infrared spectroscopy), powder X-ray diffraction, high temperature X-ray diffraction, scanning electron and transmission electron microscopy are used for the characterization of Sn6O4(OH)4 and the investigation of its selective decomposition into SnO or SnO2. Spectroscopic and X-ray diffraction results indicate that SnO is formed by the removal of water from crystalline Sn6O4(OH)4. SEM shows octahedral morphology of the Sn6O4(OH)4, SnO and SnO2 with particle size from 400 nm-2 μm during solid state conversion. Solution phase transformation of Sn6O4(OH)4 to SnO2 occurs in the presence of potassium glutarate and oxygen. SnO2 particles are 15-20 nm in size.

  9. Combinatorial development of Cu2SnS3 as an earth abundant photovoltaic absorber

    Science.gov (United States)

    Baranowski, Lauryn L.

    The development of high efficiency, earth abundant photovoltaic absorbers is critical if photovoltaics are to be implemented on the TW scale. Although traditional thin films absorbers such as Cu(In,Ga)Se2 and CdTe have achieved over 20% device efficiencies, the ultimately scalability of these devices may be limited by elemental scarcity and toxicity issues. To date, the most successful earth abundant thin film absorber is Cu2ZnSn(S,Se) 4, which has achieved 12.6% efficiency as of 2014. However, chemical complexity and disorder issues with this material have made the path to higher efficiency CZTSSe devices unclear. As a result, many researchers are now exploring alternative earth abundant absorber materials. In this thesis, we apply our "rapid development" methodology to the exploration of alternative photovoltaic absorbers. The rapid development (RD) methodology, consisting of exploration, research, and development stages, uses complementary theory and experiment to assess candidate materials and down-select in each stage. The overall result is that, in the time span of ~2-3 years, we are able to rapidly go from tens of possible absorber materials to 1-2 working PV device prototypes. Here, we demonstrate the RD approach as applied to the Cu-Sn-S system. We begin our investigation of the Cu-Sn-S system by evaluating the thermodynamic stability, electrical transport, electronic structure, and optical and defect properties of candidate materials using complementary theory and experiment. We find that Cu2SnS3 is the most promising absorber candidate because of its strong optical absorption, tunable doping, and wide stability range. Our other candidate compounds suffer from serious flaws that preclude them from being successful photovoltaic absorbers, including too high experimental conductivity (Cu4SnS4), or poor hole transport and low absorption coefficient (Cu4Sn7S16). Next, we investigate the doping and defect physics of Cu2SnS 3. We identify the origins of the

  10. Multiform structures of SnO2 nanobelts

    International Nuclear Information System (INIS)

    Duan Junhong; Gong Jiangfeng; Huang Hongbo; Zhao Xiaoning; Cheng Guangxu; Yu Zhongzhen; Yang Shaoguang

    2007-01-01

    Multiform SnO 2 microstructures were synthesized by a facile thermal evaporation of tin grains. The product was characterized with a variety of techniques to obtain the structural and optical information. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed a large percentage of acute angle zigzag nanobelts with perfectly periodic morphology. High resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) patterns revealed that the zigzag nanobelts were single crystalline and their zone axis was along the [010] crystal direction. The growth mechanism of zigzag nanobelts was proposed based on TEM characterization and thermodynamic analysis. The zigzag nanobelts were deduced to be formed by changing the growth direction from [101-bar] to [101] or vice versa. The photoluminescence (PL) spectroscopy of the nanobelts showed a broad and strong luminescence emission centred at 550 nm

  11. The tin-rich copper lithium stannides: Li3Cu6Sn4 and Li2CuSn2

    International Nuclear Information System (INIS)

    Fuertauer, Siegfried; Flandorfer, Hans; Effenberger, Herta S.

    2015-01-01

    The Sn rich ternary intermetallic compounds Li 3 Cu 6 Sn 4 (CSD-427097) and Li 2 CuSn 2 (CSD-427098) were synthesized from the pure elements by induction melting and annealing at 400 C. Structural investigations were performed by powder- and single-crystal XRD. Li 3 Cu 6 Sn 4 crystallizes in space group P6/mmm; it is structurally related to but not isotypic with MgFe 6 Ge 6 (a = 5.095(2) Aa, c = 9.524(3) Aa; wR 2 = 0.059; 239 unique F 2 -values, 17 free variables). Li 3 Cu 6 Sn 4 is characterized by two sites with a mixed Cu:Sn occupation. In contrast to all other Cu-Li-Sn compounds known so far, any mixed occupation was found for Cu-Li pairs only. In addition, one Li site is only half occupied. The second Sn rich phase is Li 2 CuSn 2 (space group I4 1 /amd, a = 4.4281(15) Aa, c = 19.416(4) Aa; wR 2 = 0.033; 213 unique F 2 -values, 12 atom free variables); it is the only phase in the Cu-Li-Sn system which is noted for full ordering. Both crystal structures exhibit 3D-networks which host Li atoms in channels. They are important for understanding the lithiation mechanism in Cu-Sn electrodes for Li-ion batteries.

  12. Effect of Sn Composition in Ge1- x Sn x Layers Grown by Using Rapid Thermal Chemical Vapor Deposition

    Science.gov (United States)

    Kil, Yeon-Ho; Kang, Sukill; Jeong, Tae Soo; Shim, Kyu-Hwan; Kim, Dae-Jung; Choi, Yong-Dae; Kim, Mi Joung; Kim, Taek Sung

    2018-05-01

    The Ge1- x Sn x layers were grown by using rapid thermal chemical-vapor deposition (RTCVD) on boron-doped p-type Si (100) substrates with Sn compositions up to x = 0.83%. In order to obtain effect of the Sn composition on the structural and the optical characteristics, we utilized highresolution X-ray diffraction (HR-XRD), etch pit density (EPD), atomic force microscopy (AFM), Raman spectroscopy, and photocurrent (PC) spectra. The Sn compositions in the Ge1- x Sn x layers were found to be of x = 0.00%, 0.51%, 0.65%, and 0.83%. The root-mean-square (RMS) of the surface roughness of the Ge1- x Sn x layer increased from 2.02 nm to 3.40 nm as the Sn composition was increased from 0.51% to 0.83%, and EPD was on the order of 108 cm-2. The Raman spectra consist of only one strong peak near 300 cm-1, which is assigned to the Ge-Ge LO peaks and the Raman peaks shift to the wave number with increasing Sn composition. Photocurrent spectra show near energy band gap peaks and their peak energies decrease with increasing Sn composition due to band-gap bowing in the Ge1- x Sn x layer. An increase in the band gap bowing parameter was observed with increasing Sn composition.

  13. Isoscaling in central {sup 124}Sn+{sup 64}Ni, {sup 112}Sn+{sup 58}Ni collisions at 35 A MeV

    Energy Technology Data Exchange (ETDEWEB)

    Geraci, E.; Bruno, M.; D' Agostino, M. E-mail: dagostino@bo.infn.it; De Filippo, E.; Pagano, A.; Vannini, G.; Alderighi, M.; Anzalone, A.; Auditore, L.; Baran, V.; Barna, R.; Bartolucci, M.; Berceanu, I.; Blicharska, J.; Bonasera, A.; Borderie, B.; Bougault, R.; Brzychczyk, J.; Cardella, G.; Cavallaro, S.; Chbihi, A.; Cibor, J.; Colonna, M.; De Pasquale, D.; Di Toro, M.; Giustolisi, F.; Grzeszczuk, A.; Guazzoni, P.; Guinet, D.; Iacono-Manno, M.; Italiano, A.; Kowalski, S.; La Guidara, E.; Lanzalone, G.; Lanzano, G.; Le Neindre, N.; Li, S.; Lo Nigro, S.; Maiolino, C.; Majka, Z.; Manfredi, G.; Paduszynski, T.; Papa, M.; Petrovici, M.; Piasecki, E.; Pirrone, S.; Politi, G.; Pop, A.; Porto, F.; Rivet, M.F.; Rosato, E.; Russo, S.; Russotto, P.; Sechi, G.; Simion, V.; Sperduto, M.L.; Steckmeyer, J.C.; Trifiro, A.; Trimarchi, M.; Vigilante, M.; Wieleczko, J.P.; Wilczynski, J.; Wu, H.; Xiao, Z.; Zetta, L.; Zipper, W

    2004-02-23

    {sup 124}Sn+{sup 64}Ni and {sup 112}Sn+{sup 58}Ni reactions at 35 A MeV incident energy were studied by using the 688 Si-CsI telescopes of the forward part (1 deg. {<=}{theta}{sub lab}{<=}30 deg.) of CHIMERA multi-detector. The most central part, 1% of the total measured cross section was selected by means of a multidimensional analysis of the experimental observables. The detected isotopes of light fragments (3{<=}Z{<=}8) provided information on breakup temperatures of the emitting sources. The space-time structure of these sources was deduced from fragment correlations. An odd-even effect in the fragment production, enhanced by the isospin of the entrance channel, was observed. Freeze-out unbound neutron-to-proton relative densities for both studied reactions have been deduced, indicating for a possible isospin distillation mechanism related to a phenomenon of the liquid-gas phase transition in asymmetric systems.

  14. Microstructure control of Zr-Nb-Sn alloy with Mo addition for HWR pressure tube application

    International Nuclear Information System (INIS)

    Hwang, S. K.; Kim, M. H.; Kim, J. H.; Kwon, S. I.; Kim, Y. S.

    1997-01-01

    As a basic research to develop the material for heavy water reactor pressure tube application the effect of Mo addition to Zr-Nb-Sn alloy was studied for the purpose of minimizing the amount of cold working while maintaining a high strength. To select the target alloy system we first designed various alloy compositions and chose Zr-Nb-Sn and Zr-Nb-Mo through multi-regression analysis of the relationship between the basic properties and the compositions. Plasma arc melting was used to produce the alloys and the microstructure change introduced by the processing steps including hot forging, beta-heat treatment, hot rolling, cold rolling and recrystallization heat treatment was investigated. Recrystallization of Zr-Nb-Sn was retarded by adding Mo and this resulted in a fine grain structure in Zr-Nb-Sn-Mo alloy. Beside the retarding effect recrystallization, Mo increased the amount of residual beta phase and showed an indication of precipitation hardening, which added up to the possibility of applying the alloy for the desired usage. (author)

  15. Remarkably Enhanced Room-Temperature Hydrogen Sensing of SnO₂ Nanoflowers via Vacuum Annealing Treatment.

    Science.gov (United States)

    Liu, Gao; Wang, Zhao; Chen, Zihui; Yang, Shulin; Fu, Xingxing; Huang, Rui; Li, Xiaokang; Xiong, Juan; Hu, Yongming; Gu, Haoshuang

    2018-03-23

    In this work, SnO₂ nanoflowers synthesized by a hydrothermal method were employed as hydrogen sensing materials. The as-synthesized SnO₂ nanoflowers consisted of cuboid-like SnO₂ nanorods with tetragonal structures. A great increase in the relative content of surface-adsorbed oxygen was observed after the vacuum annealing treatment, and this increase could have been due to the increase in surface oxygen vacancies serving as preferential adsorption sites for oxygen species. Annealing treatment resulted in an 8% increase in the specific surface area of the samples. Moreover, the conductivity of the sensors decreased after the annealing treatment, which should be attributed to the increase in electron scattering around the defects and the compensated donor behavior of the oxygen vacancies due to the surface oxygen adsorption. The hydrogen sensors of the annealed samples, compared to those of the unannealed samples, exhibited a much higher sensitivity and faster response rate. The sensor response factor and response rate increased from 27.1% to 80.2% and 0.34%/s to 1.15%/s, respectively. This remarkable enhancement in sensing performance induced by the annealing treatment could be attributed to the larger specific surface areas and higher amount of surface-adsorbed oxygen, which provides a greater reaction space for hydrogen. Moreover, the sensors with annealed SnO₂ nanoflowers also exhibited high selectivity towards hydrogen against CH₄, CO, and ethanol.

  16. Analysis of Methanol Sensitivity on SnO2-ZnO Nanocomposite

    Science.gov (United States)

    Bassey, Enobong E.; Sallis, Philip; Prasad, Krishnamachar

    This research reports on the sensing behavior of a nanocomposite of tin dioxide (SnO2) and zinc oxide (ZnO). SnO2-ZnO nanocomposites were fabricated into sensor devices by the radio frequency sputtering method, and used for the characterization of the sensitivity behavior of methanol vapor. The sensor devices were subjected to methanol concentration of 200 ppm at operating temperatures of 150, 250 and 350 °C. A fractional difference model was used to normalize the sensor response, and determine the sensitivity of methanol on the sensor. Response analysis of the SnO2-ZnO sensors to the methanol was most sensitive at 350 °C, followed by 250 and 150 °C. Supported by the morphology (FE-SEM, AFM) analyses of the thin films, the sensitivity behavior confirmed that the nanoparticles of coupled SnO2 and ZnO nanocomposites can promote the charge transportation, and be used to fine-tune the sensitivity of methanol and sensor selectivity to a desired target gas.

  17. Compositional effects in Ag_2ZnSnSe_4 thin films and photovoltaic devices

    International Nuclear Information System (INIS)

    Gershon, Talia; Sardashti, Kasra; Lee, Yun Seog; Gunawan, Oki; Singh, Saurabh; Bishop, Douglas; Kummel, Andrew C.; Haight, Richard

    2017-01-01

    Ag_2ZnSnSe_4 (AZTSe) is a relatively new n-type photovoltaic (PV) absorber material which has recently demonstrated a conversion efficiency of ∼5% in a Schottky device architecture. To date, little is known about how the influence of composition on AZTSe material properties and the resulting PV performance. In this study, the Ag/Sn ratio is shown to be critical in the controlling grain growth, non-radiative recombination, and the bulk defect structure of the absorber. Insufficient Ag (relative to Zn and Sn) results in small grains, low photoluminescence intensities, and band gap narrowing, possibly due to an increase in the bulk defect density. Additionally, etching the AZTSe films in KCN prior to junction formation is found to be important for achieving reproducible efficiencies. Surface analysis using Auger Nanoprobe Microscopy analysis reveals that a KCN etch can selectively remove potentially harmful Ag-rich secondary phases, therefore improving the MoO_3/AZTSe junction quality. Moreover, grain boundaries in AZTSe are found to be enriched in Sn and O following KCN; the role this oxide plays in surface passivation and junction formation has yet to be determined.

  18. Preparation and structural characterization of SnO2 and GeO2 methanol steam reforming thin film model catalysts by (HR)TEM

    International Nuclear Information System (INIS)

    Lorenz, Harald; Zhao Qian; Turner, Stuart; Lebedev, Oleg I.; Van Tendeloo, Gustaaf; Kloetzer, Bernhard; Rameshan, Christoph; Penner, Simon

    2010-01-01

    Structure, morphology and composition of different tin oxide and germanium oxide thin film catalysts for the methanol steam reforming (MSR) reaction have been studied by a combination of (high-resolution) transmission electron microscopy, selected area electron diffraction, dark-field imaging and electron energy-loss spectroscopy. Deposition of the thin films on NaCl(0 0 1) cleavage faces has been carried out by thermal evaporation of the respective SnO 2 and GeO 2 powders in varying oxygen partial pressures and at different substrate temperatures. Preparation of tin oxide films in high oxygen pressures (10 -1 Pa) exclusively resulted in SnO phases, at and above 473 K substrate temperature epitaxial growth of SnO on NaCl(0 0 1) leads to well-ordered films. For lower oxygen partial pressures (10 -3 to 10 -2 Pa), mixtures of SnO and β-Sn are obtained. Well-ordered SnO 2 films, as verified by electron diffraction patterns and energy-loss spectra, are only obtained after post-oxidation of SnO films at temperatures T ≥ 673 K in 10 5 Pa O 2 . Preparation of GeO x films inevitably results in amorphous films with a composition close to GeO 2 , which cannot be crystallized by annealing treatments in oxygen or hydrogen at temperatures comparable to SnO/SnO 2 . Similarities and differences to neighbouring oxides relevant for selective MSR in the third group of the periodic system (In 2 O 3 and Ga 2 O 3 ) are also discussed with the aim of cross-correlation in formation of nanomaterials, and ultimately, also catalytic properties.

  19. SnO and SnO·CoO nanocomposite as high capacity anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Das, B., E-mail: bijoy822000@gmail.com; Reddy, M.V.; Chowdari, B.V.R, E-mail: phychowd@nus.edu.sg

    2016-02-15

    Highlights: • The preparation methods are simple, low cost and can be scaled up for large production. • SnO is cheap, non-toxic and eco-friendly. • SnO shows high reversible capacity (Theoretical reversible capacity: 875 mA h g{sup −1}). • We showed high reversible capacity and columbic efficiency for SnO and SnO based composites. • We addressed the capacity degradation by introducing secondary phase (CoO and CNT etc.) - Abstract: We prepared SnO nanoparticles (SnO–S) and SnO·CoO nanocomposites (SnO·CoO–B) as anodes for lithium ion batteries (LIBs) by chemical and ball-milling approaches, respectively. They are characterized by X-ray diffraction and TEM techniques. The Li- storage performance are evaluated by galvanostatic cycling and cyclic voltammetry. The SnO–S and SnO·CoO–B showed improved cycling performance due to their finite particle size (i.e. nano-size) and presence of secondary phase (CoO). Better cycling stability is noticed for SnO·CoO–B with the expense of their reversible capacity. Also, addition of carbon nanotubes (CNT) to SnO–S further improved the cycling performance of SnO–S. When cycled at 60 mA g{sup −1}, the first-cycle reversible capacities of 635, 590 and 460 (±10) mA h g{sup −1} are noticed for SnO–S, SnO@CNT and SnO·CoO–B, respectively. The capacity fading observed are 3.7 and 1.8 mA h g{sup −1} per cycle for SnO–S and SnO@CNT, respectively; whereas 1–1.2 mA h g{sup −1} per cycle for SnO·CoO–B. All the samples show high coulombic efficiency, 96–98% in the range of 5–50 cycles.

  20. In Situ High-Resolution Transmission Electron Microscopy (TEM) Observation of Sn Nanoparticles on SnO2 Nanotubes Under Lithiation.

    Science.gov (United States)

    Cheong, Jun Young; Chang, Joon Ha; Kim, Sung Joo; Kim, Chanhoon; Seo, Hyeon Kook; Shin, Jae Won; Yuk, Jong Min; Lee, Jeong Yong; Kim, Il-Doo

    2017-12-01

    We trace Sn nanoparticles (NPs) produced from SnO2 nanotubes (NTs) during lithiation initialized by high energy e-beam irradiation. The growth dynamics of Sn NPs is visualized in liquid electrolytes by graphene liquid cell transmission electron microscopy. The observation reveals that Sn NPs grow on the surface of SnO2 NTs via coalescence and the final shape of agglomerated NPs is governed by surface energy of the Sn NPs and the interfacial energy between Sn NPs and SnO2 NTs. Our result will likely benefit more rational material design of the ideal interface for facile ion insertion.

  1. Atomic-Layer-Deposited SnO2 as Gate Electrode for Indium-Free Transparent Electronics

    KAUST Repository

    Alshammari, Fwzah Hamud

    2017-08-04

    Atomic-layer-deposited SnO2 is used as a gate electrode to replace indium tin oxide (ITO) in thin-film transistors and circuits for the first time. The SnO2 films deposited at 200 °C show low electrical resistivity of ≈3.1 × 10−3 Ω cm with ≈93% transparency in most of the visible range of the electromagnetic spectrum. Thin-film transistors fabricated with SnO2 gates show excellent transistor properties including saturation mobility of 15.3 cm2 V−1 s−1, a low subthreshold swing of ≈130 mV dec−1, a high on/off ratio of ≈109, and an excellent electrical stability under constant-voltage stressing conditions to the gate terminal. Moreover, the SnO2-gated thin-film transistors show excellent electrical characteristics when used in electronic circuits such as negative channel metal oxide semiconductor (NMOS) inverters and ring oscillators. The NMOS inverters exhibit a low propagation stage delay of ≈150 ns with high DC voltage gain of ≈382. A high oscillation frequency of ≈303 kHz is obtained from the output sinusoidal signal of the 11-stage NMOS inverter-based ring oscillators. These results show that SnO2 can effectively replace ITO in transparent electronics and sensor applications.

  2. Cryogenic in situ microcompression testing of Sn

    International Nuclear Information System (INIS)

    Lupinacci, A.; Kacher, J.; Eilenberg, A.; Shapiro, A.A.; Hosemann, P.; Minor, A.M.

    2014-01-01

    Characterizing plasticity mechanisms below the ductile-to-brittle transition temperature is traditionally difficult to accomplish in a systematic fashion. Here, we use a new experimental setup to perform in situ cryogenic mechanical testing of pure Sn micropillars at room temperature and at −142 °C. Subsequent electron microscopy characterization of the micropillars shows a clear difference in the deformation mechanisms at room temperature and at cryogenic temperatures. At room temperature, the Sn micropillars deformed through dislocation plasticity, while at −142 °C they exhibited both higher strength and deformation twinning. Two different orientations were tested, a symmetric (1 0 0) orientation and a non-symmetric (4 5 ¯ 1) orientation. The deformation mechanisms were found to be the same for both orientations

  3. The dipole response of {sup 132}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Schrock, Philipp; Aumann, Thomas; Johansen, Jacob; Schindler, Fabia [IKP, TU Darmstadt (Germany); Boretzky, Konstanze [GSI Helmholtzzentrum (Germany); Rossi, Dominic [Michigan State University (United States); Collaboration: R3B-Collaboration

    2015-07-01

    The Isovector Giant Dipole Resonance (IVGDR) is a well-known collective excitation in which all protons oscillate against all neutrons of a nucleus. In neutron-rich nuclei an additional low-lying dipole excitation occurs, often denoted as Pygmy Dipole Resonance (PDR). To study the PDR in exotic Sn-isotopes, an experiment has been successfully performed with the upgraded R{sup 3}B-LAND setup at GSI. The complete-kinematics measurement of all reaction participants allows for the reconstuction of the excitation energy and, hence, the extraction of the dipole strength. Presented are the main features of the experiment, the analysis concept and the current status of the analysis of the dipole response of the doubly-magic isotope {sup 132}Sn.

  4. Magnetic disaccommodation in Sn substituted magnetite

    International Nuclear Information System (INIS)

    Hernandez-Gomez, P.; Bendimya, K.; Francisco, C. de; Munoz, J.M.; Alejos, O.; Torres, C.

    2001-01-01

    The relaxation of the initial magnetic permeability has been measured in polycrystalline Sn-doped magnetite with nominal composition Sn x Fe 3-x O 4 with x ranging from x=0 to 0.6. In the temperature range between 80 and 500 K, the time decay of the initial permeability after sample demagnetization has been represented by means of isochronal disaccommodation curves, which show the presence of different relaxation processes at 250 K (IV' peak), 275 K (IV), 300 K (III), 400 K (II) and 440 K (I). This behavior is explained on the basis of the disaccommodation of vacancy-doped magnetite and another similar tetravalent substitution, as the previously analyzed Ti-doped magnetite

  5. A review and prospects for Nb3Sn superconductor development

    Science.gov (United States)

    Xu, Xingchen

    2017-09-01

    Nb3Sn superconductors have significant applications in constructing high-field (>10 T) magnets. This article briefly reviews development of Nb3Sn superconductor and proposes prospects for further improvement. It is shown that significant improvement of critical current density (J c) is needed for future accelerator magnets. After a brief review of the development of Nb3Sn superconductors, the factors controlling J c are summarized and correlated with their microstructure and chemistry. The non-matrix J c of Nb3Sn conductors is mainly determined by three factors: the fraction of current-carrying Nb3Sn phase in the non-matrix area, the upper critical field B c2, and the flux line pinning capacity. Then prospects to improve the three factors are discussed respectively. An analytic model was developed to show how the ratios of precursors determine the phase fractions after heat treatment, based on which it is predicted that the limit of current-carrying Nb3Sn fraction in subelements is ∼65%. Then, since B c2 is largely determined by the Nb3Sn stoichiometry, a thermodynamic/kinetic theory is presented to show what essentially determines the Sn content of Nb3Sn conductors. This theory explains the influences of Sn sources and Ti addition on stoichiometry and growth rate of Nb3Sn layers. Next, to improve flux pinning, previous efforts in this community to introduce additional pinning centers to Nb3Sn wires are reviewed, and an internal oxidation technique is described. Finally, prospects for further improvement of non-matrix J c of Nb3Sn conductors are discussed, and it is seen that the only opportunity for further significantly improving J c lies in improving flux pinning.

  6. Negative-ion states

    International Nuclear Information System (INIS)

    Compton, R.N.

    1982-01-01

    In this brief review, we discuss some of the properties of atomic and molecular negative ions and their excited states. Experiments involving photon reactions with negative ions and polar dissociation are summarized. 116 references, 14 figures

  7. Negative ion detachment processes

    International Nuclear Information System (INIS)

    Champion, R.L.; Doverspike, L.D.

    1990-10-01

    This paper discusses the following topics: H - and D - collisions with atomic hydrogen; collisional decomposition of SF 6 - ; two-electron loss processes in negative ion collisions; associative electron detachment; and negative ion desorption from surfaces

  8. Comparison of recent SnIa datasets

    International Nuclear Information System (INIS)

    Sanchez, J.C. Bueno; Perivolaropoulos, L.; Nesseris, S.

    2009-01-01

    We rank the six latest Type Ia supernova (SnIa) datasets (Constitution (C), Union (U), ESSENCE (Davis) (E), Gold06 (G), SNLS 1yr (S) and SDSS-II (D)) in the context of the Chevalier-Polarski-Linder (CPL) parametrization w(a) = w 0 +w 1 (1−a), according to their Figure of Merit (FoM), their consistency with the cosmological constant (ΛCDM), their consistency with standard rulers (Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO)) and their mutual consistency. We find a significant improvement of the FoM (defined as the inverse area of the 95.4% parameter contour) with the number of SnIa of these datasets ((C) highest FoM, (U), (G), (D), (E), (S) lowest FoM). Standard rulers (CMB+BAO) have a better FoM by about a factor of 3, compared to the highest FoM SnIa dataset (C). We also find that the ranking sequence based on consistency with ΛCDM is identical with the corresponding ranking based on consistency with standard rulers ((S) most consistent, (D), (C), (E), (U), (G) least consistent). The ranking sequence of the datasets however changes when we consider the consistency with an expansion history corresponding to evolving dark energy (w 0 ,w 1 ) = (−1.4,2) crossing the phantom divide line w = −1 (it is practically reversed to (G), (U), (E), (S), (D), (C)). The SALT2 and MLCS2k2 fitters are also compared and some peculiar features of the SDSS-II dataset when standardized with the MLCS2k2 fitter are pointed out. Finally, we construct a statistic to estimate the internal consistency of a collection of SnIa datasets. We find that even though there is good consistency among most samples taken from the above datasets, this consistency decreases significantly when the Gold06 (G) dataset is included in the sample

  9. Discovery of 7 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Castro, N.; Clocchiatti, A.; Stone, G.; Nicholls, B.; Fernandez, J. M.; Cacella, P.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.

    2018-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  10. Discovery of 9 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Castro, N.; Clocchiatti, A.; Cacella, P.; Wiethoff, W.; Krannich, G.; Stone, G.; Kiyota, S.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.

    2018-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  11. Discovery of 8 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Kiyota, S.; Wiethoff, W.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.

    2018-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  12. Discovery of Six ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Stone, G.; Kiyota, S.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.; Cornect, R.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  13. Discovery of 8 ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Tomasella, Lina; Krannich, G.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Nicholls, B.; Cacella, P.; Kiyota, S.

    2018-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  14. Discovery of Eight ASAS-SN Supernovae

    Science.gov (United States)

    Stone, G.; Brimacombe, J.; Cacella, P.; Farfan, R. G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Trappett, D.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  15. Discovery of Four ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Kiyota, S.; Cruz, I.; Stone, G.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  16. Discovery of Nine ASAS-SN Supernovae

    Science.gov (United States)

    Cacella, P.; Brimacombe, J.; Fernandez, J. M.; Kiyota, S.; Krannich, G.; Koff, R. A.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Aslan, L.; Bock, G.; Stone, G.

    2018-01-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  17. Discovery of Five ASAS-SN Supernovae

    Science.gov (United States)

    Brimacombe, J.; Stone, G.; Kiyota, S.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.

    2018-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we discovered several new transient sources.

  18. Calorimetric investigation on the Pb-Sm and Sn-Sm alloys

    International Nuclear Information System (INIS)

    Berrada, A.-E.-A.; Claire, Y.; Chafik el Idrissi, M.; Castanet, R.

    1997-01-01

    The integral enthalpy of formation of the Sm-Pb and Sm-Sn melts at 1203 K, h f , was determined by direct reaction calorimetry (drop method) in the Pb and Sn rich sides with the help of a high-temperature Tian-Calvet calorimeter. The results can be fitted respectively with reference to the mole fraction of samarium, x, as follows: f /kJmol -1 =x(1-x)(-109.8 -372.0.7x) with 0 Sm f /kJmol -1 =x(1- x)(-277.0+105.4x) with 0 Sm -1 respectively. Such negative values suggest the existence of a strong short-range order in the liquid state. The stoichiometry and the thermal stability of these associations needs additional thermodynamic determinations concerning mainly the free enthalpy of formation. It will be determined by Knudsen-effusion combined with mass spetrometry in a further work. (orig.)

  19. Scanning Tunneling Microscopy study and unusual transport properties of the topological semimetal a-Sn

    Science.gov (United States)

    Ruan, Jiawei

    Weyl semimetals are new states of quantum matter with topological Weyl nodes near Fermi level in the bulk and Fermi arcs at the surface, which are paid a lot attention in recently years. Here#¬we report another topological semimetal a-Sn., which is double Weyl semimetal in the magnetic field and Dirac semimetal in an appropriate in-plane strain. By combing Landau level spectroscopy and quasiparticle interference, we obtain the linear dispersion near the Dirac point within strain while quadratic band dispersion near Γpoint without strain. We also observe the negative longitudinal magnetoresistance (LMR) in both two system, which is caused by chiral anomaly. However ,the LMR profiles of strained a-Sn have a little rise and then descend while the unstrained one drop directly, which is due to the different type of Weyl semimetal and further confirm our prediction.

  20. Thermoelectric properties of SnSe compound

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Xinhong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Lu, Pengfei, E-mail: photon@bupt.edu.cn [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Wu, Liyuan; Han, Lihong [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Liu, Gang [School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Song, Yuxin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Shumin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden)

    2015-09-15

    Highlights: • The electronic and thermoelectric properties of SnSe bulk material are studied. • The ZT can reach as high as 1.87 along yy and 1.6 along zz direction at 800k. • SnSe is an indirect-band material, and SOC has little effect on the band structure. • The high ZT can be attributed to the intrinsically ultralow thermal conductivity. - Abstract: A first-principles study and Boltzmann transport theory have been performed to evaluate the electronic structure and thermoelectric properties of SnSe compound. The energy band structure and density of states are studied in detail. The electronic transport coefficients are then calculated as a function of chemical potential or temperature within the assumption of the constant relaxation time. The figure of merit ZT is obtained with the use of calculated thermoelectric properties and can reach as high as 1.87 along yy and 1.6 along zz direction at 800 K. Our theoretical result agrees well with previous experimental data.

  1. Thermoelectric properties of SnSe compound

    International Nuclear Information System (INIS)

    Guan, Xinhong; Lu, Pengfei; Wu, Liyuan; Han, Lihong; Liu, Gang; Song, Yuxin; Wang, Shumin

    2015-01-01

    Highlights: • The electronic and thermoelectric properties of SnSe bulk material are studied. • The ZT can reach as high as 1.87 along yy and 1.6 along zz direction at 800k. • SnSe is an indirect-band material, and SOC has little effect on the band structure. • The high ZT can be attributed to the intrinsically ultralow thermal conductivity. - Abstract: A first-principles study and Boltzmann transport theory have been performed to evaluate the electronic structure and thermoelectric properties of SnSe compound. The energy band structure and density of states are studied in detail. The electronic transport coefficients are then calculated as a function of chemical potential or temperature within the assumption of the constant relaxation time. The figure of merit ZT is obtained with the use of calculated thermoelectric properties and can reach as high as 1.87 along yy and 1.6 along zz direction at 800 K. Our theoretical result agrees well with previous experimental data

  2. New nuclear structure data beyond 136Sn

    Directory of Open Access Journals (Sweden)

    Lozeva Radomira

    2018-01-01

    Full Text Available Exotic nuclei beyond the 132Sn double shell-closure are influenced by both the Sn superfluity and the evolving collectivity only few nucleons away. Toward even more neutron-rich nuclei, especially at intermediate mass number, the interplay between single-particle and collective particle-hole excitations competes. In some cases with the extreme addition of neutrons also other effects as the formation of neutron skin, stabilization as sub-shell gaps or orbital crossings may be expected. The knowledge of nuclear ingredients is especially interesting beyond 132Sn and little is known on how the excitation modes develop with the addition of both protons and neutrons and for example systematic prompt and decay studies can be such very sensitive probe. Recently, we have approached this region of nuclei in several experimental measurements following 238U projectile fission on 9Be and n-induced fission on 241Pu and 235U. Consistent data analysis allows to access various spins and excitation energies and provide new input to theory. Examples from these studies on several nuclei in the A~140 region were presented during the conference together with the possible interpretation of the new data. Here, we will illustrate one example on 136I using two complementary data sets.

  3. New nuclear structure data beyond 136Sn

    Science.gov (United States)

    Lozeva, Radomira

    2018-05-01

    Exotic nuclei beyond the 132Sn double shell-closure are influenced by both the Sn superfluity and the evolving collectivity only few nucleons away. Toward even more neutron-rich nuclei, especially at intermediate mass number, the interplay between single-particle and collective particle-hole excitations competes. In some cases with the extreme addition of neutrons also other effects as the formation of neutron skin, stabilization as sub-shell gaps or orbital crossings may be expected. The knowledge of nuclear ingredients is especially interesting beyond 132Sn and little is known on how the excitation modes develop with the addition of both protons and neutrons and for example systematic prompt and decay studies can be such very sensitive probe. Recently, we have approached this region of nuclei in several experimental measurements following 238U projectile fission on 9Be and n-induced fission on 241Pu and 235U. Consistent data analysis allows to access various spins and excitation energies and provide new input to theory. Examples from these studies on several nuclei in the A 140 region were presented during the conference together with the possible interpretation of the new data. Here, we will illustrate one example on 136I using two complementary data sets.

  4. VERY LATE PHOTOMETRY OF SN 2011fe

    International Nuclear Information System (INIS)

    Kerzendorf, W. E.; Taubenberger, S.; Seitenzahl, I. R.; Ruiter, A. J.

    2014-01-01

    The Type Ia supernova SN 2011fe is one of the closest supernovae of the past decades. Due to its proximity and low dust extinction, this object provides a very rare opportunity to study the extremely late time evolution (>900 days) of thermonuclear supernovae. In this Letter, we present our photometric data of SN 2011fe taken at an unprecedented late epoch of ≈930 days with GMOS-N mounted on the Gemini North telescope (g = 23.43 ± 0.28, r = 24.14 ± 0.14, i = 23.91 ± 0.18, and z = 23.90 ± 0.17) to study the energy production and retention in the ejecta of SN 2011fe. Together with previous measurements by other groups, our result suggests that the optical supernova light curve can still be explained by the full thermalization of the decay positrons of 56 Co. This is in spite of theoretical predicted effects (e.g., infrared catastrophe, positron escape, and dust) that advocate a substantial energy redistribution and/or loss via various processes that result in a more rapid dimming at these very late epochs

  5. Sentential Negation in English

    Science.gov (United States)

    Mowarin, Macaulay

    2009-01-01

    This paper undertakes a detailed analysis of sentential negation in the English language with Chomsky's Government-Binding theory of Transformational Grammar as theoretical model. It distinguishes between constituent and sentential negation in English. The essay identifies the exact position of Negation phrase in an English clause structure. It…

  6. A facile inexpensive route for SnS thin film solar cells with SnS{sub 2} buffer

    Energy Technology Data Exchange (ETDEWEB)

    Gedi, Sreedevi [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Minna Reddy, Vasudeva Reddy, E-mail: drmvasudr9@gmail.com [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Pejjai, Babu [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Jeon, Chan-Wook [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Park, Chinho, E-mail: chpark@ynu.ac.kr [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Ramakrishna Reddy, K.T., E-mail: ktrkreddy@gmail.com [Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India)

    2016-05-30

    Graphical abstract: PYS spectra of SnS/SnS{sub 2} interface and the related band diagram. - Highlights: • A low cost SnS solar cell is developed using chemical bath deposition. • We found E{sub I} & χ of SnS (5.3 eV & 4.0 eV) and SnS{sub 2} (6.9 eV & 4.1 eV) films from PYS. • Band offsets of 0.1 eV (E{sub c}) and 1.6 eV (E{sub v}) are estimated for SnS/SnS{sub 2} junction. • SnS based solar cell showed a conversion efficiency of 0.51%. - Abstract: Environment-friendly SnS based thin film solar cells with SnS{sub 2} as buffer layer were successfully fabricated from a facile inexpensive route, chemical bath deposition (CBD). Layer studies revealed that as-grown SnS and SnS{sub 2} films were polycrystalline; (1 1 1)/(0 0 1) peaks as the preferred orientation; 1.3 eV/2.8 eV as optical band gaps; and showed homogeneous microstructure with densely packed grains respectively. Ionization energy and electron affinity values were found by applying photoemission yield spectroscopy (PYS) to the CBD deposited SnS and SnS{sub 2} films for the first time. These values obtained as 5.3 eV and 4.0 eV for SnS films; 6.9 eV and 4.1 eV for SnS{sub 2} films. The band alignment of SnS/SnS{sub 2} junction showed TYPE-II heterostructure. The estimated conduction and valance band offsets were 0.1 eV and 1.6 eV respectively. The current density–voltage (J–V) measurements of the cell showed open circuit voltage (V{sub oc}) of 0.12 V, short circuit current density (J{sub sc}) of 10.87 mA cm{sup −2}, fill factor (FF) of 39% and conversion efficiency of 0.51%.

  7. Anchoring ultrafine Pd nanoparticles and SnO2 nanoparticles on reduced graphene oxide for high-performance room temperature NO2 sensing.

    Science.gov (United States)

    Wang, Ziying; Zhang, Tong; Zhao, Chen; Han, Tianyi; Fei, Teng; Liu, Sen; Lu, Geyu

    2018-03-15

    In this paper, we demonstrate room-temperature NO 2 gas sensors using Pd nanoparticles (NPs) and SnO 2 NPs decorated reduced graphene oxide (Pd-SnO 2 -RGO) hybrids as sensing materials. It is found that ultrafine Pd NPs and SnO 2 NPs with particle sizes of 3-5 nm are attached to RGO nanosheets. Compared to SnO 2 -RGO hybrids, the sensor based on Pd-SnO 2 -RGO hybrids exhibited higher sensitivity at room temperature, where the response to 1 ppm NO 2 was 3.92 with the response time and recovery time being 13 s and 105 s. Moreover, such sensor exhibited excellent selectivity, and low detection limit (50 ppb). In addition to high transport capability of RGO as well as excellent NO 2 adsorption ability derived from ultrafine SnO 2 NPs and Pd NPs, the superior sensing performances of the hybrids were attributed to the synergetic effect of Pd NPs, SnO 2 NPs and RGO. Particularly, the excellent sensing performances were related to high conductivity and catalytic activity of Pd NPs. Finally, the sensing mechanism for NO 2 sensing and the reason for enhanced sensing performances by introduction of Pd NPs are also discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Treatment of nanowaste via fast crystal growth: with recycling of nano-SnO2 from electroplating sludge as a study case.

    Science.gov (United States)

    Zhuang, Zanyong; Xu, Xinjiang; Wang, Yongjing; Wang, Yandi; Huang, Feng; Lin, Zhang

    2012-04-15

    The treatment of industrial sludge containing amorphous/nanophase metal oxides or hydroxides is one of the vital issues in hazardous waste disposal. In this work, we developed a strategy to recycle nano-SnO(2) from tinplate electroplating sludge. It revealed that the major components of this sludge were acid soluble Sn and Fe amorphous phases. By introducing NaOH as a mineralizer, a fast growth of amorphous Sn compound into acid-insoluble SnO(2) nanowires was achieved selectively. Thus, the as-formed nano-SnO(2) could be recycled via dissolving other solid compositions in the sludge by using acid. The role of NaOH on accelerating both the Oriented Attachment (OA) and Ostwald Ripening (OR) growth of SnO(2) was discussed, which was regarded as a critical factor for treating the sludge. A pilot-scale experiment was conducted to treat 2.3 kg original sludge and the recycling of about 90 g nano-SnO(2) was achieved. We anticipate this work can provide a good example for the recycling of valuable metals from industrial sludge containing fine metal oxides or hydroxides. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Negative ion sources

    International Nuclear Information System (INIS)

    Ishikawa, Junzo; Takagi, Toshinori

    1983-01-01

    Negative ion sources have been originally developed at the request of tandem electrostatic accelerators, and hundreds of nA to several μA negative ion current has been obtained so far for various elements. Recently, the development of large current hydrogen negative ion sources has been demanded from the standpoint of the heating by neutral particle beam injection in nuclear fusion reactors. On the other hand, the physical properties of negative ions are interesting in the thin film formation using ions. Anyway, it is the present status that the mechanism of negative ion action has not been so fully investigated as positive ions because the history of negative ion sources is short. In this report, the many mechanisms about the generation of negative ions proposed so far are described about negative ion generating mechanism, negative ion source plasma, and negative ion generation on metal surfaces. As a result, negative ion sources are roughly divided into two schemes, plasma extraction and secondary ion extraction, and the former is further classified into the PIG ion source and its variation and Duoplasmatron and its variation; while the latter into reflecting and sputtering types. In the second half of the report, the practical negative ion sources of each scheme are described. If the mechanism of negative ion generation will be investigated more in detail and the development will be continued under the unified know-how as negative ion sources in future, the development of negative ion sources with which large current can be obtained for any element is expected. (Wakatsuki, Y.)

  10. Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes

    Science.gov (United States)

    Takahashi, Junichi; Nakahara, Sumio; Hisada, Shigeyoshi; Fujita, Takeyoshi

    2004-10-01

    It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry, typical alloys have narrowed down to Sn-Ag-Cu and Sn-Zn lead-free solder. In this study, solderability of Pb-free solder that are Sn-Ag-Cu and Sn-Zn-Bi alloy was studied on soldering using YAG (yttrium aluminum garnet) laser and diode laser. Experiments were peformed in order to determine the range of soldering parameters for obtaining an appropriate wettability based on a visual inspection. Joining strength of surface mounting chip components soldered on PCB (printed circuit board) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics of eutectic Sn-Pb alloy and under different power density were examined. As a result, solderability of Sn-Ag-Cu (Pb-free) solder paste are equivalent to that of coventional Sn-Pb solder paste, and are superior to that of Sn-Zn-Bi solder paste in the laser soldering method.

  11. Hierarchical Graphene-Encapsulated Hollow SnO2@SnS2 Nanostructures with Enhanced Lithium Storage Capability.

    Science.gov (United States)

    Xu, Wangwang; Xie, Zhiqiang; Cui, Xiaodan; Zhao, Kangning; Zhang, Lei; Dietrich, Grant; Dooley, Kerry M; Wang, Ying

    2015-10-14

    Complex hierarchical structures have received tremendous attention due to their superior properties over their constitute components. In this study, hierarchical graphene-encapsulated hollow SnO2@SnS2 nanostructures are successfully prepared by in situ sulfuration on the backbones of hollow SnO2 spheres via a simple hydrothermal method followed by a solvothermal surface modification. The as-prepared hierarchical SnO2@SnS2@rGO nanocomposite can be used as anode material in lithium ion batteries, exhibiting excellent cyclability with a capacity of 583 mAh/g after 100 electrochemical cycles at a specific current of 200 mA/g. This material shows a very low capacity fading of only 0.273% per cycle from the second to the 100th cycle, lower than the capacity degradation of bare SnO2 hollow spheres (0.830%) and single SnS2 nanosheets (0.393%). Even after being cycled at a range of specific currents varied from 100 mA/g to 2000 mA/g, hierarchical SnO2@SnS2@rGO nanocomposites maintain a reversible capacity of 664 mAh/g, which is much higher than single SnS2 nanosheets (374 mAh/g) and bare SnO2 hollow spheres (177 mAh/g). Such significantly improved electrochemical performance can be attributed to the unique hierarchical hollow structure, which not only effectively alleviates the stress resulting from the lithiation/delithiation process and maintaining structural stability during cycling but also reduces aggregation and facilitates ion transport. This work thus demonstrates the great potential of hierarchical SnO2@SnS2@rGO nanocomposites for applications as a high-performance anode material in next-generation lithium ion battery technology.

  12. Changes of electronic structure of SnTe due to high concentration of Sn vacancies

    International Nuclear Information System (INIS)

    Masek, J.; Nuzhnyj, D.N.

    1997-01-01

    Non-stoichiometric Sn 1-y Te is a strongly degenerated n-type semiconductor. This is important for understanding unusual features of magnetic behaviour of Sn 1-x Gd x Te where the relative positions of the Fermi energy and the atomic d-level of Gd govern the exchange coupling.The influence of the Sn vacancies on the band structure cannot be neglect if their concentration reaches a few atomic percent. We address this problem by using a tight-binding coherent potential approach and show that although the character of the bands remains unchanged, they are modified so that ε d can come out above the heavy-hole band. (author)

  13. 0(gs)+ -->2(1)+ transition strengths in 106Sn and 108Sn.

    Science.gov (United States)

    Ekström, A; Cederkäll, J; Fahlander, C; Hjorth-Jensen, M; Ames, F; Butler, P A; Davinson, T; Eberth, J; Fincke, F; Görgen, A; Górska, M; Habs, D; Hurst, A M; Huyse, M; Ivanov, O; Iwanicki, J; Kester, O; Köster, U; Marsh, B A; Mierzejewski, J; Reiter, P; Scheit, H; Schwalm, D; Siem, S; Sletten, G; Stefanescu, I; Tveten, G M; Van de Walle, J; Van Duppen, P; Voulot, D; Warr, N; Weisshaar, D; Wenander, F; Zielińska, M

    2008-07-04

    The reduced transition probabilities, B(E2; 0(gs)+ -->2(1)+), have been measured in the radioactive isotopes (108,106)Sn using subbarrier Coulomb excitation at the REX-ISOLDE facility at CERN. Deexcitation gamma rays were detected by the highly segmented MINIBALL Ge-detector array. The results, B(E2;0(gs)+ -->2(1)+)=0.222(19)e2b2 for 108Sn and B(E2; 0(gs)+-->2(1)+)=0.195(39)e2b2 for 106Sn were determined relative to a stable 58Ni target. The resulting B(E2) values are approximately 30% larger than shell-model predictions and deviate from the generalized seniority model. This experimental result may point towards a weakening of the N=Z=50 shell closure.

  14. The strategic significance of negative externalities.

    Science.gov (United States)

    2012-12-01

    Negative externalities have competitive relevance in a market when they have selective impacts as, for : example, when a product in use imposes greater costs on consumers of rival products than on other people. : Because managers have discretion ...

  15. XRF 100316D/SN 2010bh and the nature of gamma-ray burst supernovae

    NARCIS (Netherlands)

    Cano, Z.; Bersier, D.; Guidorzi, C.; Kobayashi, S.; Levan, A.J.; Tanvir, N.R.; Wiersema, K.; D'Avanzo, P.; Fruchter, A.S.; Garnavich, P.; Gomboc, A.; Gorosabel, J.; Kasen, D.; Kopač, D.; Margutti, R.; Mazzali, P.A.; Melandri, A.; Mundell, C.G.; Nugent, P.E.; Pian, E.; Smith, R.J.; Steele, I.; Wijers, R.A.M.J.; Woosley, S.E.

    2011-01-01

    We present ground-based and Hubble Space Telescope optical and infrared observations of Swift XRF 100316D/SN 2010bh. It is seen that the optical light curves of SN 2010bh evolve at a faster rate than the archetype gamma-ray burst supernova (GRB-SN) 1998bw, but at a similar rate to SN 2006aj, an SN

  16. Sensing mechanism of SnO2/ZnO nanofibers for CH3OH sensors: heterojunction effects

    Science.gov (United States)

    Tang, Wei

    2017-11-01

    SnO2/ZnO composite nanofibers were synthesized by a simple electrospinning method. The prepared SnO2/ZnO gas sensors exhibited good linear and high response to methanol. The enhanced sensing behavior of SnO2/ZnO might be associated with the homotypic heterojunction effects formed in n-SnO2/n-ZnO nanograins boundaries. In addition, the possible sensing mechanisms of methanol on SnO2/ZnO surface were investigated by density functional theory in order to make the methanol adsorption and desorption process clear. Zn doped SnO2 model was adopted to approximate the SnO2/ZnO structure because of the calculation power limitations. Calculation results showed that when exposed to methanol, the methanol would react with bridge oxygen O2c , planar O3c and pre adsorbed oxygen vacancy on the lattice surface. The -CH3 and -OH of methanol molecule would both lose one H atom. The lost H atoms bonded with oxygen at the adsorption sites. The final products were HCHO and H2O. Electrons were transferred from methanol to the lattice surface to reduce the resistance of semiconductor gas sensitive materials, which is in agreement with the experimental phenomena. More adsorption models of other interfering gases, such as ethanol, formaldehyde and acetone will be built and calculated to explain the selectivity issue from the perspective of adsorption energy, transferred charge and density of states in the future work.

  17. Sensing mechanism of SnO2/ZnO nanofibers for CH3OH sensors: heterojunction effects

    International Nuclear Information System (INIS)

    Tang, Wei

    2017-01-01

    SnO 2 /ZnO composite nanofibers were synthesized by a simple electrospinning method. The prepared SnO 2 /ZnO gas sensors exhibited good linear and high response to methanol. The enhanced sensing behavior of SnO 2 /ZnO might be associated with the homotypic heterojunction effects formed in n -SnO 2 / n -ZnO nanograins boundaries. In addition, the possible sensing mechanisms of methanol on SnO 2 /ZnO surface were investigated by density functional theory in order to make the methanol adsorption and desorption process clear. Zn doped SnO 2 model was adopted to approximate the SnO 2 /ZnO structure because of the calculation power limitations. Calculation results showed that when exposed to methanol, the methanol would react with bridge oxygen O 2c , planar O 3c and pre adsorbed oxygen vacancy on the lattice surface. The –CH 3 and –OH of methanol molecule would both lose one H atom. The lost H atoms bonded with oxygen at the adsorption sites. The final products were HCHO and H 2 O. Electrons were transferred from methanol to the lattice surface to reduce the resistance of semiconductor gas sensitive materials, which is in agreement with the experimental phenomena. More adsorption models of other interfering gases, such as ethanol, formaldehyde and acetone will be built and calculated to explain the selectivity issue from the perspective of adsorption energy, transferred charge and density of states in the future work. (paper)

  18. Superconductivity optimization and phase formation kinetics study of internal-Sn Nb3Sn superconducting wires

    International Nuclear Information System (INIS)

    Zhang, Chaowu

    2007-07-01

    Superconductors Nb 3 Sn wires are one of the most applicable cryogenic superconducting materials and the best choice for high-field magnets exceeding 10 T. One of the most significant utilization is the ITER project which is regarded as the hope of future energy source. The high-Cu composite designs with smaller number of sub-element and non-reactive diffusion barrier, and the RRP (Restacked Rod Process) internal-Sn technology are usually applied for the wire manufacturing. Such designed and processed wires were supplied by MSA/Alstom and WST/NIN in this research. The systematic investigation on internal-Sn superconducting wires includes the optimization of heat treatment (HT) conditions, phase formation and its relation with superconductivity, microstructure analysis, and the phase formation kinetics. Because of the anfractuosity of the configuration design and metallurgical processing, the MF wires are not sufficient for studying a sole factor effect on superconductivity. Therefore, four sets of mono-element (ME) wires with different Sn ratios and different third-element addition were designed and fabricated in order to explore the relationship between phase formation and superconducting performances, particularly the A15 layer growth kinetics. Different characterization technic have been used (magnetization measurements, neutron diffraction and SEM/TEM/EDX analysis). The A15 layer thicknesses of various ME samples were measured and carried out linear and non-linear fits by means of two model equations. The results have clearly demonstrated that the phase formation kinetics of Nb 3 Sn solid-state reaction is in accordance with an n power relation and the n value is increased with the increase of HT temperature and the Sn ratio in the wire composite. (author)

  19. Premaximum observations of the type Ia SN 1990N

    International Nuclear Information System (INIS)

    Leibundgut, B.; Kirshner, R.P.; Filippenko, A.V.; Shields, J.C.; Foltz, C.B.; Phillips, M.M.; Sonneborn, G.

    1991-01-01

    Spectroscopic and photometric observations of SN 1990N were obtained at ultraviolet and optical wavelengths, beginning 14 days before maximum light. The early observations reveal important differences from spectra of SN Ia's around maximum light. Photometry and spectroscopy obtained after maximum show that SN 1990N is a typical SN Ia and that most of the observed differences are due to the early epoch of the observations. The most significant characteristics are (1) the high velocities of Ca and Si up to 22,000 km/s; (2) the presence of Co and Fe 2 weeks before maximum; and (3) the more rapid increase in the UV flux compared to the optical. The most popular models for white dwarf deflagration that have provided the standard interpretation for SN Ia's at maximum light do not reproduce the high velocities of Ca II and Si II lines observed in SN 1990N. 37 refs

  20. Development of a 117mSn preparation method

    International Nuclear Information System (INIS)

    Moraes, Vanessa; Osso Junior, Joao Alberto

    2000-01-01

    117m Sn is a radioisotope with suitable characteristics to be used in nuclear medicine as radiotherapy, when labeled with DTPA. The aim of this work is the preparation of 117m Sn from irradiation of the natural tin with proton beam at the cyclotron CV-28 of IPEN-CNEN/SP via the nuclear reaction nat Sn (p, xn) 117 Sb to 117m Sn. Due to the formation of the Sb precursor it is necessary to perform a chemical separation for Sb-Sn. The separation method used was the ion exchange, due to its utilization facilities for radioactive material. Chemical, radiochemical and radionuclidic methods were also developed for the quality control of the final product, the 117m Sn. (author)

  1. Tunneling spectroscopy on superconducting Nb3Sn with artioficial barriers

    International Nuclear Information System (INIS)

    Schneider, U.

    1984-03-01

    Tunneling diodes on Nb 3 Sn were prepared by magnetron sputtering. The superconducting transition temperatures of the Nb 3 Sn films were in the range of 5 to 18 K. An energetically low-lying structure in the tunneling density of states has been localized by detailed studies of the second derivative of the current-voltage characteristics of the diodes. This structure was found near 5.5 meV for stoichiometric Nb 3 Sn (Tsub(c) approx.= 18 K) and at 6.7 meV for understoichiometric Nb 3 Sn (Tsub(c) approx.= 5 K). The minimum in the conductance at zero energy found in the normal state could be identified to be mainly due to inelastic phonon processes of barrier phonons and Nb 3 Sn phonons. Deformations were found in the tunneling density of states of stoichiometric Nb 3 Sn diodes which lead to contradiction when explained by proximity effects. (orig./GSCH)

  2. Polemic and Descriptive Negations

    DEFF Research Database (Denmark)

    Horslund, Camilla Søballe

    2011-01-01

    to semantics and pragmatics, negations can be used in three different ways, which gives rise to a typology of three different types of negations: 1) the descriptive negation, 2) the polemic negation, and 3) the meta-linguistic negation (Nølke 1999, 4). This typology illuminates the fact that the negation...... common in certain social context or genres, while polemic negations are more likely to come up in other genres and social settings. Previous studies have shown a relation between articulatory prominence and register, which may further inform the analysis. Hence, the paper investigates how articulatory...... prominence and register may either work in concert or oppose each other with respect to the cues they provide for the interpretation....

  3. Evolution of ANB and SN-GoGn angles during craniofacial growth: A retrospective longitudinal study

    Directory of Open Access Journals (Sweden)

    Rodrigo Oyonarte

    2016-01-01

    Full Text Available Objective: The aim of this study is to describe the evolution of the ANB and SN-GoGn angles throughout development, in a longitudinal sample of Caucasian patients. Materials and Methods: Historical cephalometric records from North American individuals available at the American Association of Orthodontists Foundation Craniofacial Legacy Growth Collection website were used to carry out an exploratory longitudinal study. Lateral cephalometric radiographs of orthodontically untreated males and females were included. Individuals with three or more longitudinal cephalometric records at pre- and post-pubertal stages, with at least one postpubertal radiograph available in vertebral cervical maturation stage (cervical vertebral maturation 5 or 6, were selected. Seventy-one individuals met the inclusion criteria. ANB, SNA, SNB, and SN-GoGn angles were measured. Individuals were classified according to the latest postpubertal ANB angle available and grouped by CVM. Descriptive statistics were obtained for the cephalometric variables, and differences between genders were analyzed. Results: Forty-five individuals were classified as skeletal Class I at the end of growth, 17 as Class II, and 9 as Class III. ANB values decrease as growth occurs in every group (average ANB decrease between the stages CVM 1 and 6: Class I - 1.5°, Class II - 0.7°, and Class III - 3.1°. For SN-GoGn angle, a constant reduction was observed as skeletal maturation increased (Average SN-GoGn decrease between the stages CVM 1 and 6: Class I - 4°, Class II - 2.5°, and Class III - 4.9°. Conclusions: ANB and SN-GoGn angles decrease during growth. The magnitude varies depending on individual sagittal characteristics, Class III individuals displaying the greatest reduction, and Class II individuals the least.

  4. Surface alloying in Sn/Au(111) at elevated temperature

    Science.gov (United States)

    Sadhukhan, Pampa; Singh, Vipin Kumar; Rai, Abhishek; Bhattacharya, Kuntala; Barman, Sudipta Roy

    2018-04-01

    On the basis of x-ray photoelectron spectroscopy, we show that when Sn is deposited on Au(111) single crystal surface at a substrate temperature TS=373 K, surface alloying occurs with the formation of AuSn phase. The evolution of the surface structure and the surface morphology has been studied by low energy electron diffraction and scanning tunneling microscopy, respectively as a function of Sn coverage and substrate temperatures.

  5. Structural properties and hyperfine characterization of Sn-substituted goethites

    Energy Technology Data Exchange (ETDEWEB)

    Larralde, A.L. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Ramos, C.P. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Arcondo, B. [Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Av. Paseo Colon 850 (C1063ACV), Bs. As. (Argentina); Tufo, A.E. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Saragovi, C. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Sileo, E.E., E-mail: sileo@qi.fcen.uba.ar [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer Pure and tin-doped goethites were synthesized from Sn(II) solutions at ambient pressure and 70 Degree-Sign C. Black-Right-Pointing-Pointer The Rietveld refinement of PXRD data indicated that Sn partially substituted the Fe(III) ions. Black-Right-Pointing-Pointer The substitution provoked unit cell expansion, and a distortion of the coordination polyhedron. Black-Right-Pointing-Pointer {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV). Black-Right-Pointing-Pointer {sup 57}Fe Moessbauer spectroscopy showed a lower magnetic coupling as tin concentration increased. - Abstract: Tin-doped goethites obtained by a simple method at ambient pressure and 70 Degree-Sign C were characterized by inductively coupled plasma atomic emission spectrometry, scanning electron microscopy, Rietveld refinement of powder X-ray diffraction data, and {sup 57}Fe and {sup 119}Sn Moessbauer spectroscopy. The particles size and the length to width ratios decreased with tin-doping. Sn partially substituted the Fe(III) ions provoking unit cell expansion and increasing the crystallinity of the particles with enlarged domains that grow in the perpendicular and parallel directions to the anisotropic broadening (1 1 1) axis. Intermetallic E, E Prime and DC distances also change although the variations are not monotonous, indicating different variations in the coordination polyhedron. In general, the Sn-substituted samples present larger intermetallic distances than pure goethite, and the greatest change is shown in the E Prime distance which coincides with the c-parameter. {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV) in the samples. On the other hand, Fe(II) presence was not detected by {sup 57}Fe Moessbauer spectroscopy, suggesting the existence of vacancies in the Sn-doped samples. A lower magnetic coupling is also evidenced from the average magnetic hyperfine field values obtained as tin

  6. Fabrication of high crystalline SnS and SnS2 thin films, and their switching device characteristics

    Science.gov (United States)

    Choi, Hyeongsu; Lee, Jeongsu; Shin, Seokyoon; Lee, Juhyun; Lee, Seungjin; Park, Hyunwoo; Kwon, Sejin; Lee, Namgue; Bang, Minwook; Lee, Seung-Beck; Jeon, Hyeongtag

    2018-05-01

    Representative tin sulfide compounds, tin monosulfide (SnS) and tin disulfide (SnS2) are strong candidates for future nanoelectronic devices, based on non-toxicity, low cost, unique structures and optoelectronic properties. However, it is insufficient for synthesizing of tin sulfide thin films using vapor phase deposition method which is capable of fabricating reproducible device and securing high quality films, and their device characteristics. In this study, we obtained highly crystalline SnS thin films by atomic layer deposition and obtained highly crystalline SnS2 thin films by phase transition of the SnS thin films. The SnS thin film was transformed into SnS2 thin film by annealing at 450 °C for 1 h in H2S atmosphere. This phase transition was confirmed by x-ray diffractometer and x-ray photoelectron spectroscopy, and we studied the cause of the phase transition. We then compared the film characteristics of these two tin sulfide thin films and their switching device characteristics. SnS and SnS2 thin films had optical bandgaps of 1.35 and 2.70 eV, and absorption coefficients of about 105 and 104 cm‑1 in the visible region, respectively. In addition, SnS and SnS2 thin films exhibited p-type and n-type semiconductor characteristics. In the images of high resolution-transmission electron microscopy, SnS and SnS2 directly showed a highly crystalline orthorhombic and hexagonal layered structure. The field effect transistors of SnS and SnS2 thin films exhibited on–off drain current ratios of 8.8 and 2.1 × 103 and mobilities of 0.21 and 0.014 cm2 V‑1 s‑1, respectively. This difference in switching device characteristics mainly depends on the carrier concentration because it contributes to off-state conductance and mobility. The major carrier concentrations of the SnS and SnS2 thin films were 6.0 × 1016 and 8.7 × 1013 cm‑3, respectively, in this experiment.

  7. Phase Equilibria of Sn-Co-Cu Ternary System

    Science.gov (United States)

    Chen, Yu-Kai; Hsu, Chia-Ming; Chen, Sinn-Wen; Chen, Chih-Ming; Huang, Yu-Chih

    2012-10-01

    Sn-Co-Cu ternary alloys are promising lead-free solders, and isothermal sections of Sn-Co-Cu phase equilibria are fundamentally important for the alloys' development and applications. Sn-Co-Cu ternary alloys were prepared and equilibrated at 523 K, 1073 K, and 1273 K (250 °C, 800 °C, and 1000 °C), and the equilibrium phases were experimentally determined. In addition to the terminal solid solutions and binary intermetallic compounds, a new ternary compound, Sn3Co2Cu8, was found. The solubilities of Cu in the α-CoSn3 and CoSn2 phases at 523 K (250 °C) are 4.2 and 1.6 at. pct, respectively, while the Cu solubility in the α-Co3Sn2 phase is as high as 20.0 at. pct. The Cu solubility increases with temperature and is around 30.0 at. pct in the β-Co3Sn2 at 1073 K (800 °C). The Co solubility in the η-Cu6Sn5 phase is also significant and is 15.5 at. pct at 523 K (250 °C).

  8. The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

    Energy Technology Data Exchange (ETDEWEB)

    Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

    2008-02-15

    The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

  9. The 20th anniversary of SN1987A

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, A [KEK, High Energy Accelerator Research Organization, Oho 1-1, Tsukuba, Ibaragi, 305-0801 (Japan)], E-mail: atsuto.suzuki@kek.jp

    2008-07-15

    Observation of a neutrino burst from the supernova, SN1987A opened a new window of observational astronomy by neutrinos. And the history showed that the SN1987A neutrino burst observation was the vanguard of successive discoveries of neutrino properties by Super-Kamiokande, SNO, K2K, KamLAND and so on. On the occasion of the SN1987A 20th anniversary, the backstage story up to the discovery of the SN1987A neutrino bursts is summarized, tracing the Kamiokande log-note and including the IMB, LSD and Baksan data.

  10. Phase diagram of the ternary Zr-Ti-Sn system

    International Nuclear Information System (INIS)

    Arias, D.; Gonzalez Camus, M.

    1987-01-01

    It is well known that Ti stabilizes the high temperature cubic phase of Zr and that Sn stabilizes the low temperature hexagonal phase of Zr. The effect of Sn on the Zr-Ti diagram has been studied in the present paper. Using high purity metals, nine different alloys have been prepared, with 4-32 at % Ti, 0.7-2.2 at % Sn and Zr till 100%. Resistivity and optical and SEM metallography techniques have been employed. Effect of some impurities have been analyzed. The results are discussed and different isothermic sections of the ternary Zr-Ti-Sn diagram are presented. (Author) [es

  11. Effect of Pt:Sn atomic ratio on the preparation of PtSn/C electrocatalysts using electron beam irradiation

    International Nuclear Information System (INIS)

    Silva, Dionisio F.; Oliveira Neto, Almir; Pino, Eddy S.; Linardi, Marcelo; Spinace, Estevam V.

    2009-01-01

    PtSn/C electrocatalysts were prepared with Pt:Sn atomic ratios of 3:1, 1:1 and 1:3 in water/2-propanol using electron beam irradiation. The obtained materials were characterized by EDX, XRD and cyclic voltammetry. The ethanol electro-oxidation was studied by chronoamperometry. The XRD diffractograms of the PtSn/C electrocatalysts showed typical face-centered cubic (fcc) structure of platinum and the presence of a SnO 2 phase (cassiterite). The mean crystallite sizes of Pt fcc phase was in the range of 3.0-3.5 nm. The PtSn/C electrocatalysts were active for ethanol electro-oxidation at room temperature and the material prepared with Pt:Sn atomic ratio of 1:1 showed the best activity. (author)

  12. Effect of Pt:Sn atomic ratio on the preparation of PtSn/C electrocatalysts using electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Dionisio F.; Oliveira Neto, Almir; Pino, Eddy S.; Linardi, Marcelo; Spinace, Estevam V., E-mail: dfsilva@ipen.b, E-mail: espinace@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    PtSn/C electrocatalysts were prepared with Pt:Sn atomic ratios of 3:1, 1:1 and 1:3 in water/2-propanol using electron beam irradiation. The obtained materials were characterized by EDX, XRD and cyclic voltammetry. The ethanol electro-oxidation was studied by chronoamperometry. The XRD diffractograms of the PtSn/C electrocatalysts showed typical face-centered cubic (fcc) structure of platinum and the presence of a SnO{sub 2} phase (cassiterite). The mean crystallite sizes of Pt fcc phase was in the range of 3.0-3.5 nm. The PtSn/C electrocatalysts were active for ethanol electro-oxidation at room temperature and the material prepared with Pt:Sn atomic ratio of 1:1 showed the best activity. (author)

  13. Production of superconducting Nb3Sn wire using Nb or Nb(Ti) and Sn(Ga) solid solution powders

    International Nuclear Information System (INIS)

    Thieme, C.L.H.; Foner, S.

    1991-01-01

    This paper reports on superconducting Nb 3 Sn wire produced by the powder metallurgy method using Nb or Nb-2.9 at% Ti powder in combination with Sn-x at% Ga powders (x = 3, 4.2, 6.2 and 9.0). Ga additions to the Sn caused considerable solid solution hardening which improved its workability. It made the Nb-Sn(Ga) powder combinations convenient for swaging and extensive wire drawing. Anneals at 950 degrees C produced wires with an overall J c of 10 4 A/cm 2 at 21.9 T for wires with both Ti in the Nb and 6.2 at% Ga in the Sn. Comparison of this wire with the best Nb(Ti)-Cu-internal Sn(Ti) shows a higher J c per A15 areas, especially in fields of 22T and above

  14. Synthesis of Nanocrystalline SnO2 Modified TiO2:a Material for Carbon Monoxide Gas Sensor

    Directory of Open Access Journals (Sweden)

    A. B. BODADE

    2008-11-01

    Full Text Available Nanocrystalline SnO2 doped TiO2 having average crystallite size of 45-50 nm were synthesized by the sol-gel method and studied for gas sensing behavior to reducing gases like CO, liquefied petroleum gas (LPG, NH3 and H2. The material characterization was done by using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR and scanning electron microscope (SEM. The sensitivity measurements were carried out as a function of different operating temperature in SnO2 doped TiO2. The 15 wt.% SnO2 doped TiO2 based CO sensor shows better sensitivity at an operating temperature 240°C Incorporation of 0.5 wt% Pd improved the sensitivity, selectivity, response time and reduced the operating temperature from 240°C to 200°C for CO sensor.

  15. Study of Pd-Sn/Al{sub 2}O{sub 3} catalysts prepared by an oxide colloidal route; Etude de catalyseurs Pd-Sn/Al{sub 2}O{sub 3} prepares par voie colloidale oxyde

    Energy Technology Data Exchange (ETDEWEB)

    Verdier, St.

    2001-09-01

    The oxide colloidal route, developed in the laboratory for mono-metallic catalysts, consists in preparing a metallic oxide hydro-sol which leads to the supported catalyst after deposition onto a support and an activation stage. In this work, this method has been adapted to the preparation of alumina supported bimetallic Pd-Sn catalysts to determine its interest for the control of the properties of the bimetallic phase (size, composition and structure). In the preliminary study concerning tin oxide sols, SnO{sub 2} (size=2,3 nm) and Sn{sub 6}O{sub 4}(OH){sub 4} (size = 25 nm) nano-particles were synthesized by neutralization respectively for tin(IV) and tin(H). The control through the pH of the aggregation of the PdO and SnO{sub 2} particles revealed that increasing oxide solubility promotes integral re-dispersion of the oxide particles. To synthesize oxide bimetallic sols, three strategies were defined. Copolymerization (formation of a mixed oxide nano-sol by cross condensation of both metals) does not lead to a mixed oxide Pd-Sn phase. Surface precipitation (neutralization of the second metal in the presence of the first oxide sol) yields nano-particles of both oxides in close interaction. Adsorption (adsorption of the second metal onto the first oxide sol) significantly occurs when contacting tin with a basic PdO sol (hydrolytic adsorption). The characterization and the assessment of the catalytic properties (selective hydrogenation of buta-1,3-diene) of the catalysts prepared by deposition of oxide bimetallic sols showed that the oxide colloidal route allows the control of the properties of the supported bimetallic phase. Moreover, our results display that both Pd-Sn alloy formation and,aggregation of the metallic particles contribute to increase the selectivity for this reaction. (author)

  16. Transcriptome analysis of genes related to resistance against powdery mildew in wheat-Thinopyrum alien addition disomic line germplasm SN6306.

    Science.gov (United States)

    Li, Quanquan; Niu, Zubiao; Bao, Yinguang; Tian, Qiuju; Wang, Honggang; Kong, Lingrang; Feng, Deshun

    2016-09-15

    Wheat powdery mildew, which is mainly caused by Blumeria graminis f. sp. tritici (Bgt), seriously damages wheat production. The wheat-Thinopyrum intermedium alien addition disomic line germplasm SN6306, being one of the important sources of genes for wheat resistance, is highly resistant to Bgt E09 and to many other powdery mildew physiological races. However, knowledge on the resistance mechanism of SN6306 remains limited. Our study employed high-throughput RNA sequencing based on next-generation sequencing technology (Illumina) to obtain an overview of the transcriptome characteristics of SN6306 and its parent wheat Yannong 15 (YN15) during Bgt infection. The sequencing generated 104,773 unigenes, 9909 of which showed varied expression levels. Among the 9909 unigenes, 1678 unigenes showed 0 reads in YN15. The expression levels in Bgt-inoculated SN6306 and YN15 of exactly 39 unigenes that showed 0 or considerably low reads in YN15 were validated to identify the genes involved in Bgt resistance. Among the 39 unigenes, 12 unigenes were upregulated in SN6306 by 3-45 times. These unigenes mainly encoded kinase, synthase, proteases, and signal transduction proteins, which may play an important role in the resistance against Bgt. To confirm whether the unigenes that showed 0 reads in YN15 are really unique to SN6306, 8 unigenes were cloned and sequenced. Results showed that the selected unigenes are more similar to SN6306 and Th. intermedium than to the wheat cultivar YN15. The sequencing results further confirmed that the unigenes showing 0 reads in YN15 are unique to SN6306 and are most likely derived from Th. intermedium (Host) Nevski. Thus, the genes from Th. intermedium most probably conferred the resistance of SN6306 to Bgt. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Yanhui Sun

    2018-01-01

    Full Text Available 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.

  18. Effect of Bronsted Acids and Bases, and Lewis Acid (Sn(2+)) on the Regiochemistry of the Reaction of Amines with Trifluoromethyl-β-diketones: Reaction of 3-Aminopyrrole to Selectively Produce Regioisomeric 1H-Pyrrolo[3,2-b]pyridines.

    Science.gov (United States)

    De Rosa, Michael; Arnold, David; Hartline, Douglas; Truong, Linda; Verner, Roman; Wang, Tianwei; Westin, Christian

    2015-12-18

    Reaction of 3-aminopyrrole (as its salt) with trifluoromethyl-β-diketones gave γ-1H-pyrrolo[3,2-b]pyridines via reaction at the less reactive carbonyl group. The trifluoromethyl group increased the electrophilicity of the adjacent carbonyl group and decreased the basicity of the hydroxyl group of the CF3 amino alcohol formed. This amino alcohol was formed faster, but its subsequent dehydration to the β-enaminone was slow resulting in the preferential formation of the γ-regioisomer. Reaction of 4,4,4-trifluoro-1-phenyl-1,3-butadione with 3-aminopyrrole was carried out using a series of 6 amine buffers. Yields of the α-1H-pyrrolo[3,2-b]pyridine increased as the pKa of the amine buffer decreased. Surprisingly the yield went down at higher pKas. There was a change in mechanism as the reaction mixture became more basic. With strong amines trifluoromethyl-β-diketones were present mainly or completely as the enolate. Under reductive conditions (3-nitropyrrole/Sn/AcOH/trifluoromethyl-β-diketone) the α-1H-pyrrolo[3,2-b]pyridine was the major product as a result of Lewis acid catalysis by Sn(2+). Similar α-regiochemistry was observed when the reaction of the 3-aminopyrrole salt with trifluoromethyl-β-diketones was carried out in the presence of base and tin(II) acetate.

  19. Negative Ion Density Fronts

    International Nuclear Information System (INIS)

    Igor Kaganovich

    2000-01-01

    Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

  20. Temperature varying photoconductivity of GeSn alloys grown by chemical vapor deposition with Sn concentrations from 4% to 11%

    Science.gov (United States)

    Hart, John; Adam, Thomas; Kim, Yihwan; Huang, Yi-Chiau; Reznicek, Alexander; Hazbun, Ramsey; Gupta, Jay; Kolodzey, James

    2016-03-01

    Pseudomorphic GeSn layers with Sn atomic percentages between 4.5% and 11.3% were grown by chemical vapor deposition using digermane and SnCl4 precursors on Ge virtual substrates grown on Si. The layers were characterized by x-ray diffraction rocking curves and reciprocal space maps. Photoconductive devices were fabricated, and the dark current was found to increase with Sn concentration. The responsivity of the photoconductors was measured at a wavelength of 1.55 μm using calibrated laser illumination at room temperature and a maximum value of 2.7 mA/W was measured for a 4.5% Sn device. Moreover, the responsivity for higher Sn concentration was found to increase with decreasing temperature. Spectral photoconductivity was measured using Fourier transform infrared spectroscopy. The photoconductive absorption edge continually increased in wavelength with increasing tin percentage, out to approximately 2.4 μm for an 11.3% Sn device. The direct band gap was extracted using Tauc plots and was fit to a bandgap model accounting for layer strain and Sn concentration. This direct bandgap was attributed to absorption from the heavy-hole band to the conduction band. Higher energy absorption was also observed, which was thought to be likely from absorption in the light-hole band. The band gaps for these alloys were plotted as a function of temperature. These experiments show the promise of GeSn alloys for CMOS compatible short wave infrared detectors.

  1. Microstructural investigation and SnO nanodefects in spray-pyrolyzed SnO2 thin films

    DEFF Research Database (Denmark)

    Thanachayanont, Chanchana; Yordsri, Visittapong; Boothroyd, Chris

    2011-01-01

    Spray pyrolysis is one of the most cost-effective methods to prepare SnO2 films due to its ability to deposit large uniform area, low fabrication cost, simplicity and low deposition temperature. Conventionally, scanning electron microscopy (SEM) and X-Ray Diffraction (XRD) are routinely used...... diffraction (CBED). It was found that large grain-size vertically-aligned columnar SnO2 grains were formed after a few layers of small grain-size randomly oriented SnO2 grains. Moreover, CBED showed the presence of SnO nanodefects that had not been reported before and could not be detected by SEM or XRD....

  2. Fluid-sensitive nanoscale switching with quantum levitation controlled by α -Sn/β -Sn phase transition

    Science.gov (United States)

    Boström, Mathias; Dou, Maofeng; Malyi, Oleksandr I.; Parashar, Prachi; Parsons, Drew F.; Brevik, Iver; Persson, Clas

    2018-03-01

    We analyze the Lifshitz pressure between silica and tin separated by a liquid mixture of bromobenzene and chlorobenzene. We show that the phase transition from semimetallic α -Sn to metallic β -Sn can switch Lifshitz forces from repulsive to attractive. This effect is caused by the difference in dielectric functions of α -Sn and β -Sn , giving both attractive and repulsive contributions to the total Lifshitz pressure in different frequency regions controlled by the composition of the intervening liquid mixture. In this way, one may be able to produce phase-transition-controlled quantum levitation in a liquid medium.

  3. Interfacial Bonding Energy on the Interface between ZChSnSb/Sn Alloy Layer and Steel Body at Microscale

    Directory of Open Access Journals (Sweden)

    Jianmei Wang

    2017-09-01

    Full Text Available To investigate the performance of bonding on the interface between ZChSnSb/Sn and steel body, the interfacial bonding energy on the interface of a ZChSnSb/Sn alloy layer and the steel body with or without Sn as an intermediate layer was calculated under the same loadcase using the molecular dynamics simulation software Materials Studio by ACCELRYS, and the interfacial bonding energy under different Babbitt thicknesses was compared. The results show that the bonding energy of the interface with Sn as an intermediate layer is 10% larger than that of the interface without a Sn layer. The interfacial bonding performances of Babbitt and the steel body with Sn as an intermediate layer are better than those of an interface without a Sn layer. When the thickness of the Babbitt layer of bushing is 17.143 Å, the interfacial bonding energy reaches the maximum, and the interfacial bonding performance is optimum. These findings illustrate the bonding mechanism of the interfacial structure from the molecular level so as to ensure the good bonding properties of the interface, which provides a reference for the improvement of the bush manufacturing process from the microscopic point of view.

  4. Interfacial Bonding Energy on the Interface between ZChSnSb/Sn Alloy Layer and Steel Body at Microscale.

    Science.gov (United States)

    Wang, Jianmei; Xia, Quanzhi; Ma, Yang; Meng, Fanning; Liang, Yinan; Li, Zhixiong

    2017-09-25

    To investigate the performance of bonding on the interface between ZChSnSb/Sn and steel body, the interfacial bonding energy on the interface of a ZChSnSb/Sn alloy layer and the steel body with or without Sn as an intermediate layer was calculated under the same loadcase using the molecular dynamics simulation software Materials Studio by ACCELRYS, and the interfacial bonding energy under different Babbitt thicknesses was compared. The results show that the bonding energy of the interface with Sn as an intermediate layer is 10% larger than that of the interface without a Sn layer. The interfacial bonding performances of Babbitt and the steel body with Sn as an intermediate layer are better than those of an interface without a Sn layer. When the thickness of the Babbitt layer of bushing is 17.143 Å, the interfacial bonding energy reaches the maximum, and the interfacial bonding performance is optimum. These findings illustrate the bonding mechanism of the interfacial structure from the molecular level so as to ensure the good bonding properties of the interface, which provides a reference for the improvement of the bush manufacturing process from the microscopic point of view.

  5. Validation of a model for predicting smear-positive active pulmonary tuberculosis in patients with initial acid-fast bacilli smear-negative sputum

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Jun-Jun [Department of Chest Medicine, Section of Thoracic Imaging, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City (China); Chia Nan University of Pharmacy and Science, Tainan (China); Meiho University, Pingtung (China); Pingtung Christian Hospital, Pingtung (China); Heng Chun Christian Hospital, Pingtung (China)

    2018-01-15

    The objective of this study was to develop a predictive model for final smear-positive (SP) active pulmonary tuberculosis (aPTB) in patients with initial negative acid fast bacilli (AFB) sputum smears (iSN-SP-aPTB) based on high-resolution computed tomography (HRCT). Eighty (126, 21) patients of iSN-SP-aPTB and 402 (459, 876) patients of non-initial positive acid fast bacilli (non-iSP) pulmonary disease without iSN-SP-aPTB were included in a derivation (validation, prospective) cohort. HRCT characteristics were analysed, and multivariable regression and receiver operating characteristic (ROC) curve analysis was performed to develop a score predictive of iSN-SP-aPTB. The derivation cohort showed clusters of nodules/mass of the right upper lobe or left upper lobe were independent predictors of iSN-SP-aPTB, while bronchiectasis in the right middle lobe or left lingual lobe were negatively associated with iSN-SP-aPTB. A predictive score for iSN-SP-aPTB based on these findings was tested in the validation and prospective cohorts. With an ideal cut-off score = 1, the sensitivity, specificity, positive predictive value, and negative predictive value of the prediction model were 87.5% (90%, 90.5%), 99% (97.1%, 98.4%), 94.6% (81.3%, 57.5%), and 97.6% (97%, 99.8%) in the derivation (validation, prospective) cohorts, respectively. The model may help identify iSN-SP-aPTB among patients with non-iSP pulmonary diseases. circle Smear-positive active pulmonary tuberculosis that is initial smear-negative (iSN-SP-aPTB) is infectious. (orig.)

  6. Structural, Optical and Ethanol Sensing Properties of Dy-Doped SnO2 Nanoparticles

    Science.gov (United States)

    Shaikh, F. I.; Chikhale, L. P.; Nadargi, D. Y.; Mulla, I. S.; Suryavanshi, S. S.

    2018-04-01

    We report a facile co-precipitation synthesis of dysprosium (Dy3+) doped tin oxide (SnO2) thick films and their use as gas sensors. The doping percentage (Dy3+) was varied from 1 mol.% to 4 mol.% with the step of 1 mol.%. As-produced material with varying doping levels were sintered in air; and by using a screen printing technique, their thick films were developed. Prior to sensing performance investigations, the films were examined for structural, morphological and compositional properties using x-ray diffraction, a field emission scanning electron microscope, a transmission electron microscope, selected area electron diffraction, energy dispersive analysis by x-rays, Fourier transform infrared spectroscopy and Raman spectroscopic techniques. The structural analyses revealed formation of single phase nanocrystalline material with tetragonal rutile structure of SnO2. The morphological analyses confirmed the nanocrystalline porous morphology of as-developed material. Elemental analysis defined the composition of material in accordance with the doping concentration. The produced sensor material exhibited good response towards different reducing gases (acetone, ethanol, LPG, and ammonia) at different operating temperatures. The present study confirms that the Dy3+ doping in SnO2 enhances the response towards ethanol with reduction in operating temperature. Particularly, 3 mol.% Dy3+ doped sensor exhibited the highest response (˜ 92%) at an operating temperature of 300°C with better selectivity, fast response (˜ 13 s) and recovery (˜ 22 s) towards ethanol.

  7. Determination of Sn{sup 2+} in lyophilized radiopharmaceuticals by voltammetry, using hydrochloric acid as electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Dadda, Adilio S.; Teixeira, Ariane C.; Feltes, Paula K.; Campos, Maria M.; Moriguchi-Jeckel, Cristina M., E-mail: adiliosd@yahoo.com.br [Pontifícia Universidade Católica do Rio Grande do Sul (PUC-RS), Porto Alegre-RS (Brazil); Leite, Carlos E. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre-RS (Brazil)

    2014-07-01

    This work aimed to develop and validate a routine method for the specific determination of Sn{sup 2+} 2-methoxy isobutyl isonitrile (MIBI) radiopharmaceutical kits. A voltammetric electrochemical technique was used for the analysis. Screening experiments revealed that 1 mol L{sup -1} HCl electrolyte showed the best results, among all the tested solutions. Stability experiments showed a gradual decline in the current of MIBI, and 23 days after the preparation of the solution, the current corresponding to stannous ion disappeared. To confirm the selectivity of the technique using HCl, we have induced oxidation of SnCl{sub 2} that resulted in a proportional decline of the current in the voltammogram. The reliability of the method was observed with the values of precision and accuracy intra- and inter-assay, and also its robustness. We provide novel evidence on the selective detection of Sn{sup 2+} in the presence of its oxidized form in radiopharmaceutical kits, by using 1 mol L{sup -1} HCl as electrolyte. (author)

  8. Phase Equilibria in the Sn-Rich Corner of the Ni-Sb-Sn System

    Czech Academy of Sciences Publication Activity Database

    Mishra, R.; Kroupa, Aleš; Zemanová, Adéla; Ipser, H.

    2013-01-01

    Roč. 42, č. 4 (2013), s. 646-653 ISSN 0361-5235 Institutional support: RVO:68081723 Keywords : lead-free solder * high-temperature solder * Ni-Sb-Sn system Subject RIV: BJ - Thermodynamics Impact factor: 1.675, year: 2013

  9. `Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31

    Directory of Open Access Journals (Sweden)

    Wilhelm Klein

    2015-07-01

    Full Text Available The crystal structure of the title compound was previously reported with composition `Pd20Sn13' [Sarah et al. (1981. Z. Metallkd, 72, 517–520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6 were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtained via a solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3:0.62 (3. One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b.

  10. Cloning and expression profiling of the PacSnRK2 and PacPP2C gene families during fruit development, ABA treatment, and dehydration stress in sweet cherry.

    Science.gov (United States)

    Shen, Xinjie; Guo, Xiao; Zhao, Di; Zhang, Qiang; Jiang, Yuzhuang; Wang, Yantao; Peng, Xiang; Wei, Yan; Zhai, Zefeng; Zhao, Wei; Li, Tianhong

    2017-10-01

    Plant SNF1-related protein kinase 2 (SnRK2) and protein phosphatase 2C (PP2C) family members are core components of the ABA signal transduction pathway. SnRK2 and PP2C proteins have been suggested to play crucial roles in fruit ripening and improving plant tolerance to drought stress, but supporting genetic information has been lacking in sweet cherry (Prunus avium L.). Here, we cloned six full-length SnRK2 genes and three full-length PP2C genes from sweet cherry cv. Hong Deng. Quantitative PCR analysis revealed that PacSnRK2.2, PacSnRK2.3, PacSnRK2.6, and PacPP2C1-3 were negatively regulated in fruits in response to exogenous ABA treatment, PacSnRK2.4 and PacSnRK2.5 were upregulated, and PacSnRK2.1 expression was not affected. The ABA treatment also significantly promoted the accumulation of anthocyanins in sweet cherry fruit. The expression of all PacSnRK2 and PacPP2C genes was induced by dehydration stress, which also promoted the accumulation of drought stress signaling molecules in the sweet cherry fruits, including ABA, soluble sugars, and anthocyanin. Furthermore, a yeast two-hybrid analysis demonstrated that PacPP2C1 interacts with all six PacSnRK2s, while PacPP2C3 does not interact with PacSnRK2.5. PacPP2C2 does not interact with PacSnRK2.1 or PacSnRK2.4. These results indicate that PacSnRK2s and PacPP2Cs may play a variety of roles in the sweet cherry ABA signaling pathway and the fruit response to drought stress. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Tin phosphide-based anodes for sodium-ion batteries: synthesis via solvothermal transformation of Sn metal and phase-dependent Na storage performance

    Science.gov (United States)

    Shin, Hyun-Seop; Jung, Kyu-Nam; Jo, Yong Nam; Park, Min-Sik; Kim, Hansung; Lee, Jong-Won

    2016-01-01

    There is a great deal of current interest in the development of rechargeable sodium (Na)-ion batteries (SIBs) for low-cost, large-scale stationary energy storage systems. For the commercial success of this technology, significant progress should be made in developing robust anode (negative electrode) materials with high capacity and long cycle life. Sn-P compounds are considered promising anode materials that have considerable potential to meet the required performance of SIBs, and they have been typically prepared by high-energy mechanical milling. Here, we report Sn-P-based anodes synthesised through solvothermal transformation of Sn metal and their electrochemical Na storage properties. The temperature and time period used for solvothermal treatment play a crucial role in determining the phase, microstructure, and composition of the Sn-P compound and thus its electrochemical performance. The Sn-P compound prepared under an optimised solvothermal condition shows excellent electrochemical performance as an SIB anode, as evidenced by a high reversible capacity of ~560 mAh g−1 at a current density of 100 mA g−1 and cycling stability for 100 cycles. The solvothermal route provides an effective approach to synthesising Sn-P anodes with controlled phases and compositions, thus tailoring their Na storage behaviour. PMID:27189834

  12. The converged Sn algorithm for nuclear criticality

    International Nuclear Information System (INIS)

    Ganapol, B. D.; Hadad, K.

    2009-01-01

    A new discrete ordinates algorithm to determine the multiplication factor of a 1D nuclear reactor, based on Bengt Carlson's S n method, is presented. The algorithm applies the Romberg and Wynn-epsilon accelerators to accelerate a 1D, one-group S n solution to its asymptotic limit. We demonstrate the feasibility of the Converged Sn (CSn) solution on several one-group criticality benchmark compilations. The new formulation is especially convenient since it enables highly accurate critical fluxes and eigenvalues using the most fundamental transport algorithm. (authors)

  13. Asymmetry of the SN 1987A envelope

    International Nuclear Information System (INIS)

    Chugaj, N.N.

    1991-01-01

    The origin of the peculiar structure in the profiles of the emission lines observed in the spectrum of SN 1987A, namely, (1) redshift of maxima, and (2) fine structure of hydrogen lines, is considered. Among the three proposed hypothesis for the redshift, at least two (electron scattering in the spherically-symmetric envelope, and geometrical effects in the fragmented envelope) have serious drawbacks. More favorable is the third hypothesis which invokes asymmetric distribution of 56 Ni and of the iron-peak elements

  14. Recent results on SN 1987A

    International Nuclear Information System (INIS)

    Woosley, S.E.; Pinto, P.A.; Weaver, T.A.

    1988-01-01

    Several critical issues recently raised by observations of SN 1987A are addressed. These include: the evolution of the pre-supernova star, why it was blue, what its composition and core structure were; the detailed isotopic composition of the ejecta; why and to what extent the supernova composition was mixed in velocity space; the interpretation of recently observed infrared lines, especially their profiles and the existence of red-shifted 'wings'; and what has become of the neutron star. 64 refs., 14 figs., 1 tab

  15. The NASA SN1987A program

    International Nuclear Information System (INIS)

    Teegarden, B.J.

    1988-01-01

    The existing and planned experiments for making gamma-ray observations of SN1987A are reviewed. The main emphasis is on the NASA program which consists primarily of balloon-borne instruments. Some 11--13 experiments are or will be available. Four have already flown from Alice Springs, Australia with null results. Campaigns are planned on nominal six month centers with more possible if gamma-rays are detected. In addition long duration flights from Australia to South America are planned for January 88 and 89

  16. Dilute Magnetic Semiconductor Cu2FeSnS4 Nanocrystals with a Novel Zincblende Structure

    Directory of Open Access Journals (Sweden)

    Xiaolu Liang

    2012-01-01

    Full Text Available Diluted magnetic semiconductor Cu2FeSnS4 nanocrystals with a novel zincblende structure have been successfully synthesized by a hot-injection approach. Cu+, Fe2+, and Sn4+ ions occupy the same position in the zincblende unit cell, and their occupancy possibilities are 1/2, 1/4, and 1/4, respectively. The nanocrystals were characterized by means of X-ray diffraction (XRD, transmission electron microscopy (TEM, selected area electron diffraction (SAED, energy-dispersive spectroscopy (EDS, and UV-vis-NIR absorption spectroscopy. The nanocrystals have an average size of 7.5 nm and a band gap of 1.1 eV and show a weak ferromagnetic behavior at low temperature.

  17. Modelling the aqueous and nonaqueous interfaces for CO2 electro-reduction over Sn catalysts

    Science.gov (United States)

    Sheng, Tian; Sun, Shi-Gang

    2018-01-01

    In CO2 electroreduction, Sn catalysts with a high overpotential for hydrogen evolution reaction and a high selectivity towards formic acid formation are very attractive. Many efforts have been made for improving the catalytic performance and for understanding the mechanisms. In electrochemistry, the role of solvents for surface reactions was deserved to be investigated, in particular for some nonaqueous solvents. Here, we have modeled the aqueous (water) and nonaqueous (acetonitrile and dichloromethane) for investigation of CO2 electroreduction on Sn surface, by constrained ab initio molecular dynamics simulations and thermodynamic integrations, including a number of explicit solvent molecules in computational models. It was found that CO2 reduction is initiated from formate formation and solvents, in particular, water can effectively facilitate the reaction.

  18. Thermal properties and phase transition in the fluoride, (NH4)3SnF7

    International Nuclear Information System (INIS)

    Kartashev, A.V.; Gorev, M.V.; Bogdanov, E.V.; Flerov, I.N.; Laptash, N.M.

    2016-01-01

    Calorimetric, dilatometric and differential thermal analysis studies were performed on (NH 4 ) 3 SnF 7 for a wide range of temperatures and pressures. Large entropy (δS 0 =22 J/mol K) and elastic deformation (δ(ΔV/V) 0 =0.89%) jumps have proven that the Pa-3↔Pm-3m phase transition is a strong first order structural transformation. A total entropy change of ΔS 0 =32.5 J/mol K is characteristic for the order–disorder phase transition, and is equal to the sum of entropy changes in the related material, (NH 4 ) 3 TiF 7 , undergoing transformation between the two cubic phases through the intermediate phases. Hydrostatic pressure decreases the stability of the high temperature Pm-3m phase in (NH 4 ) 3 SnF 7 , contrary to (NH 4 ) 3 TiF 7 , characterised by a negative baric coefficient. The effect of experimental conditions on the chemical stability of (NH 4 ) 3 SnF 7 was observed. - Graphical abstract: Strong first order structural transformation Pa-3↔Pm-3m in (NH 4 ) 3 SnF 7 is associated with very large total entropy change of ΔS 0 =32.5 J/mol K characteristic for the ordering processes and equal to the sum of entropy changes in the related (NH 4 ) 3 TiF 7 undergoing transformation between the same two cubic phases through the intermediate phases. - Highlights: • (NH 4 ) 3 SnF 7 undergoes strong first order Pa-3↔Pm-3m phase transition. • Anomalous behaviour of ΔC p and ΔV/V exists far below phase transition temperature. • Structural distortions are accompanied by huge total entropy change ΔS≈Rln50. • High pressure strongly increases the stability of Pa-3 phase in (NH 4 ) 3 SnF 7 . • Entropy of the Pa-3↔Pm-3m phase transition does not depend on pressure.

  19. Oxidation and reduction kinetics of eutectic SnPb, InSn, and AuSn: a knowledge base for fluxless solder bonding applications

    DEFF Research Database (Denmark)

    Kuhmann, Jochen Friedrich; Preuss, A.; Adolphi, B.

    1998-01-01

    : (1) SnPb; (2) InSn; (3) AuSn. The studies of the oxidation kinetics show that the growth of the native oxide, which covers the solder surfaces from the start of all soldering operations is self-limiting. The rate of oxidation on the molten, metallic solder surfaces is significantly reduced...... and reduction kinetics, are applied to flip-chip (FC) bonding experiments in vacuum with and without the injection of H2. Wetting in vacuum is excellent but the self-alignment during flip-chip soldering is restricted. The desired, perfectly self-aligned FC-bonds have been only achieved, using evaporated...

  20. A Modality Called 'Negation'

    NARCIS (Netherlands)

    Berto, F.

    2015-01-01

    I propose a comprehensive account of negation as a modal operator, vindicating a moderate logical pluralism. Negation is taken as a quantifier on worlds, restricted by an accessibility relation encoding the basic concept of compatibility. This latter captures the core meaning of the operator. While

  1. Tuning antiferromagnetic exchange interaction for spontaneous exchange bias in MnNiSnSi system

    Science.gov (United States)

    Jia, Liyun; Shen, Jianlei; Li, Mengmeng; Wang, Xi; Ma, Li; Zhen, Congmian; Hou, Denglu; Liu, Enke; Wang, Wenhong; Wu, Guangheng

    2017-12-01

    Based on almost all the data from the literature on spontaneous exchange bias (SEB), it is expected that the system will show SEB if it meets two conditions simultaneously: (i) there are the coexistence and competition of antiferromagnetic (AFM) and ferromagnetic (FM) interactions and (ii) AFM interaction should dominate but not be too strong in this competition. In order to verify this view, a systematic study on SEB has been performed in this work. Mn50Ni40Sn10 with strong FM interaction and without SEB is chosen as the mother composition, and the negative chemical pressure is introduced by the substitution of Sn by Si to enhance AFM interaction. It is found that a long-range FM ordering window is closed, and a long-range AFM ordering window is opened. As a result, SEB is triggered and a continuous tuning of the spontaneous exchange bias field (HSEB) from 0 Oe to 1300 Oe has been realized in a Mn50Ni40Sn10-xSix system by the enhanced AFM interaction.

  2. Electrolytically exfoliated graphene-loaded flame-made Ni-doped SnO2 composite film for acetone sensing.

    Science.gov (United States)

    Singkammo, Suparat; Wisitsoraat, Anurat; Sriprachuabwong, Chakrit; Tuantranont, Adisorn; Phanichphant, Sukon; Liewhiran, Chaikarn

    2015-02-11

    In this work, flame-spray-made SnO2 nanoparticles are systematically studied by doping with 0.1-2 wt % nickel (Ni) and loading with 0.1-5 wt % electrolytically exfoliated graphene for acetone-sensing applications. The sensing films (∼12-18 μm in thickness) were prepared by a spin-coating technique on Au/Al2O3 substrates and evaluated for acetone-sensing performances at operating temperatures ranging from 150 to 350 °C in dry air. Characterizations by X-ray diffraction, transmission/scanning electron microscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy and Raman spectroscopy demonstrated that Ni-doped SnO2 nanostructures had a spheriodal morphology with a polycrystalline tetragonal SnO2 phase, and Ni was confirmed to form a solid solution with SnO2 lattice while graphene in the sensing film after annealing and testing still retained its high-quality nonoxidized form. Gas-sensing results showed that SnO2 sensing film with 0.1 wt % Ni-doping concentration exhibited an optimal response of 54.2 and a short response time of ∼13 s toward 200 ppm acetone at an optimal operating temperature of 350 °C. The additional loading of graphene at 5 wt % into 0.1 wt % Ni-doped SnO2 led to a drastic response enhancement to 169.7 with a very short response time of ∼5.4 s at 200 ppm acetone and 350 °C. The superior gas sensing performances of Ni-doped SnO2 nanoparticles loaded with graphene may be attributed to the large specific surface area of the composite structure, specifically the high interaction rate between acetone vapor and graphene-Ni-doped SnO2 nanoparticles interfaces and high electronic conductivity of graphene. Therefore, the 5 wt % graphene loaded 0.1 wt % Ni-doped SnO2 sensor is a promising candidate for fast, sensitive and selective detection of acetone.

  3. Negative thermal expansion materials

    International Nuclear Information System (INIS)

    Evans, J.S.O.

    1997-01-01

    The recent discovery of negative thermal expansion over an unprecedented temperature range in ZrW 2 O 8 (which contracts continuously on warming from below 2 K to above 1000 K) has stimulated considerable interest in this unusual phenomenon. Negative and low thermal expansion materials have a number of important potential uses in ceramic, optical and electronic applications. We have now found negative thermal expansion in a large new family of materials with the general formula A 2 (MO 4 ) 3 . Chemical substitution dramatically influences the thermal expansion properties of these materials allowing the production of ceramics with negative, positive or zero coefficients of thermal expansion, with the potential to control other important materials properties such as refractive index and dielectric constant. The mechanism of negative thermal expansion and the phase transitions exhibited by this important new class of low-expansion materials will be discussed. (orig.)

  4. Phase Equilibria of the Ternary Sn-Pb-Co System at 250°C and Interfacial Reactions of Co with Sn-Pb Alloys

    Science.gov (United States)

    Wang, Chao-hong; Kuo, Chun-yi; Yang, Nian-cih

    2015-11-01

    The isothermal section of the ternary Sn-Pb-Co system at 250°C was experimentally determined through a series of the equilibrated Sn-Pb-Co alloys of various compositions. The equilibrium phases were identified on the basis of compositional analysis. For the Sn-Co intermetallic compounds (IMCs), CoSn3, CoSn2, CoSn and Co3Sn2, the Pb solubility was very limited. There exist five tie-triangle regions. The Co-Pb system involves one monotectic reaction, so the phase separation of liquid alloys near the Co-Pb side occurred prior to solidification. The immiscibility field was also determined. Additionally, interfacial reactions between Co and Sn-Pb alloys were conducted. The reaction phase for the Sn-48 at.%Pb and Sn-58 at.%Pb at 250°C was CoSn3 and CoSn2, respectively. Both of them were simultaneously formed in the Sn-53 at.%Pb/Co. The formed IMCs were closely associated to the phase equilibria relationship of the liquid-CoSn3-CoSn2 tie-triangle. Furthermore, with increasing temperatures, the phase formed in equilibrium with Sn-37 wt.%Pb was found to transit from CoSn3 to CoSn2 at 275°C. We propose a simple method of examining the phase transition temperature in the interfacial reactions to determine the boundaries of the liquid-CoSn3-CoSn2 tie-triangles at different temperatures.

  5. Pseudo single crystal, direct-band-gap Ge{sub 0.89}Sn{sub 0.11} on amorphous dielectric layers towards monolithic 3D photonic integration

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haofeng; Brouillet, Jeremy; Wang, Xiaoxin; Liu, Jifeng, E-mail: Jifeng.Liu@dartmouth.edu [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States)

    2014-11-17

    We demonstrate pseudo single crystal, direct-band-gap Ge{sub 0.89}Sn{sub 0.11} crystallized on amorphous layers at <450 °C towards 3D Si photonic integration. We developed two approaches to seed the lateral single crystal growth: (1) utilize the Gibbs-Thomson eutectic temperature depression at the tip of an amorphous GeSn nanotaper for selective nucleation; (2) laser-induced nucleation at one end of a GeSn strip. Either way, the crystallized Ge{sub 0.89}Sn{sub 0.11} is dominated by a single grain >18 μm long that forms optoelectronically benign twin boundaries with others grains. These pseudo single crystal, direct-band-gap Ge{sub 0.89}Sn{sub 0.11} patterns are suitable for monolithic 3D integration of active photonic devices on Si.

  6. SN38 conjugated hyaluronic acid gold nanoparticles as a novel system against metastatic colon cancer cells.

    Science.gov (United States)

    Hosseinzadeh, Hosniyeh; Atyabi, Fatemeh; Varnamkhasti, Behrang Shiri; Hosseinzadeh, Reza; Ostad, Seyed Nasser; Ghahremani, Mohammad Hossein; Dinarvand, Rassoul

    2017-06-30

    Combination of chemotherapy and photothermal therapy has been proposed for better treatment of metastatic colon cancer. In this study SN38, a highly potent cytotoxic agent, was conjugated to negatively charged hyaluronic acid (HA), which was deposited on the surface of the positively charged gold nanoparticles via electrostatic interaction. The drug conjugation and its interaction with gold nanoparticles were verified by 1 H NMR and UV-vis spectroscopies, respectively. The prepared SN38-HA gold NPs are negatively charged spherical nanoparticles with an average size of 75±10nm. In vitro release study revealed that drug release in acidic conditions (pH 5.2) was faster than that in physiological pH. Red light emitting diode (LED, 630nm, 30mW) was used as a light source for photothermal experiments. The drug release in acidic conditions was increased up to 30% using red LED illumination (6min) in comparison with experiment carried out indark. The cytotoxicity study on MUC1 positive HT29, SW480 colon cancer cells and MUC1 negative CHO cells, showed higher toxicity of the nanoparticles on HT29 and SW480 cell lines compared to CHO cells. Confocal microscopy images along with flow cytometry analysis confirm the cytotoxicity results. The incubation time for reaching IC50 decreases from 48h to 24h by LED illumination after nanoparticle treatment. Migratory potential of the HT29 and SW480 cell lines was reduced by co-application of SN38-HA gold NPs and LED radiation. Also anti-proliferative study indicates that LED radiation has increased the cytotoxicity of the nanoparticles and this effect is remained up to 8days. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Phase analysis of superconducting Nb-Sn materials by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Sitek, J.; Tomasich, M.; Cirak, J.; Prejsa, M.; Kruzliak, J.

    1978-01-01

    Moessbauer spectroscopy is used for the optimalization of superconducting Nb-Sn samples preparation in the form of foils. Pure phases of Nb 3 Sn, Nb 6 Sn 5 , and NbSn 2 are determined. Two series of samples are studied at 750 and 900 0 C tinning temperature respectively, and at 750, 860, 900, and 960 0 C heating temperatures. In the samples the phases Nb 3 Sn, Nb 6 Sn 5 , NbSn 2 , and the solid solution Nb-Sn phase are observed. The results from the phase analysis lead to the assumption that the percentage amount of the phases is preferentially dependent on the tinning temperature. (author)

  8. Neutron emission spectra of excited 126–140Sn nuclei

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Rajasekaran, M.

    2004-01-01

    We investigate one-neutron and two-neutron emission from 132 Sn and its neighboring isotopes due to thermal excitation. The rotational states of 132 Sn at different temperatures are investigated. The effects of separation energy and thermal excitation energy on neutron emission probability are studied. (author)

  9. Distinction between SnO2 nanoparticles synthesized using co ...

    Indian Academy of Sciences (India)

    Administrator

    pared with that of a co-precipitation-modified SnO2 nanoparticles. Keywords. SnO2 nanoparticle ... Dye-sensitized solar cells (DSSCs), which convert light to electricity by means of ... nature, additives and aging time. Nanosized particles pre-.

  10. Moderation of the 119mSn isomer radioactive decay

    International Nuclear Information System (INIS)

    Godovikov, S.K.

    1999-01-01

    The evaluation of the constant of the braked 119m Sn nuclei decay in the Moessbauer source, being for a long time in contact with a resonance shield, is carried out. The high stability of these nuclei relative to decay is established. The 119m Sn subjected to prolonged impact of the standing electromagnetic wave field become resistant to radioactive decay [ru

  11. The ASAS-SN bright supernova catalogue - III. 2016

    DEFF Research Database (Denmark)

    Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.

    2017-01-01

    This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d......This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d...

  12. Advantage and Challenges of $Nb_3Sn$ Superconducting Undulators

    Energy Technology Data Exchange (ETDEWEB)

    Zlobin, A. V. [Fermilab; Barzi, E. [Fermilab; Turrinoni, D. [Fermilab; Ivanyushenkov, Yu. [Argonne; Kesgin, I. [Argonne

    2018-04-01

    Utilization of Nb3Sn superconducting wires offers the possibility to increase undulators’ nominal operation field and temperature margin, but requires overcoming chal-lenges that are described in this paper. The achievable field levels for a Nb3Sn version of superconducting undulators being developed at APS-ANL and the conductor choice are also presented and discussed.

  13. Muon spin rotation measurements on LaNiSn

    International Nuclear Information System (INIS)

    Drew, A.J.; Lee, S.L.; Ogrin, F.Y.; Charalambous, D.; Bancroft, N.; Paul, D. McK.; Takabatake, T.; Baines, C.

    2006-01-01

    The first microscopic investigation of superconductivity in LaNiSn is reported using muon spin rotation. LaNiSn is found to be mainly a type I superconductor in an intermediate state with some evidence for type II behaviour at low temperatures, possibly due to a temperature dependent Ginzburg Landau parameter κ

  14. Reference Data for the Density, Viscosity, and Surface Tension of Liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn Eutectic Alloys

    Science.gov (United States)

    Dobosz, Alexandra; Gancarz, Tomasz

    2018-03-01

    The data for the physicochemical properties viscosity, density, and surface tension obtained by different experimental techniques have been analyzed for liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn eutectic alloys. All experimental data sets have been categorized and described by the year of publication, the technique used to obtain the data, the purity of the samples and their compositions, the quoted uncertainty, the number of data in the data set, the form of data, and the temperature range. The proposed standard deviations of liquid eutectic Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn alloys are 0.8%, 0.1%, 0.5%, 0.2%, and 0.1% for the density, 8.7%, 4.1%, 3.6%, 5.1%, and 4.0% for viscosity, and 1.0%, 0.5%, 0.3%, N/A, and 0.4% for surface tension, respectively, at a confidence level of 95%.

  15. Nonlocal Cooper pair splitting in a pSn-junction

    NARCIS (Netherlands)

    Veldhorst, M.; Brinkman, Alexander

    2010-01-01

    Perfect Cooper pair splitting is proposed, based on crossed Andreev reflection (CAR) in a p-type semiconductor-superconductor-n-type semiconductor (pSn) junction. The ideal splitting is caused by the energy filtering that is enforced by the band structure of the electrodes. The pSn junction is

  16. Josephson effects in Nb3Sn microbridges

    International Nuclear Information System (INIS)

    Lee, T.W.; Falco, C.M.

    1981-01-01

    Josephson effects in long narrow Nb/sub 3/Sn microbridges at temperatures up to 17 K were studied. These microbridges are formed by photolithographic techniques and subsequently subjected to controlled electrical discharges to modifY the intrinsic T/sub c/ of the bridge region. The bridges exhibit 10 GHz microwave steps in their I-V characteristics whose amplitudes are in agreement with the Resistively Shunted Junction (RSJ) model. I-V characteristics can be fit assuming an effective temperature approximately 15 K above the bath temperature. Structures in the I-V characteristics in the absence of microwaves were also investigated. It was demonstrated that phase-slip centers are induced at weak superconducting positions along the bridge when the S-N boundarY of an expanding hot spot reaches within a thermal healing distance. The critical current of the phase-slip center thus formed exhibits a temperature dependence (1-T/T/sub c/)/one-half/ insteady of the usual mean field result (1-T/T/sub c/)/sup 3/2/. 12 refs

  17. A Nb3Sn high field dipole

    International Nuclear Information System (INIS)

    McClusky, R.; Robins, K.E.; Sampson, W.B.

    1990-01-01

    A dipole magnet approximately 1 meter long with an 8 cm bore has been fabricated from cable made from Nb 3 Sn multifilamentary strands. The coil consists of four layers of conductor wound in pairs to eliminate internal joints. Each set of layers is separately constrained with Kevlar-epoxy bands and the complete assembly clamped in a split laminated iron yoke. The inner coil pairs were wound before heat treating while the outer coils were formed from pre-reacted cable using conventional insulation. A NbTi version of the magnet was fabricated using SSC version of the magnet was fabricated using SSC conductor to test the construction techniques. This magnet reached a maximum central field of 7.6 Tesla, at 4.4K which is very close to the limit estimated from conductor measurements. The Nb 3 Sn magnet, however, only reached a maximum field at 8.1T considerably short of the field expected from measurements on the inner cable. 7 refs., 5 figs

  18. New Pn and Sn tomographic images of the uppermost mantle beneath the Mediterranean region

    Science.gov (United States)

    Gil, A.; Díaz, J.; Gallart, J.

    2012-04-01

    We present here new images of the seismic velocity and anisotropy variations in the uppermost mantle beneath the Mediterranean region, compiled from inversion of Pn and Sn phases. The method of Hearn (1996) has been applied to Pn and Sn lectures from the catalogs of the International Seismological Center and the Spanish Instituto Geografico Nacional. A total of 1,172,293 Pn arrivals coming from 16,527 earthquakes recorded at 1,657 stations with epicentral distances between 220 km and 1400 km have been retained (331,567 arrivals from 15,487events at 961 stations for Sn). Our results, grossly consistent with available 3D tomography images, show significant features well correlated with surface geology. The Pn velocities are high (>8.2 km/s) beneath major sedimentary basins (western Alboran Sea, Valencia Trough, Adriatic Sea, Aquitaine, Guadalquivir, Rharb, Aquitaine and Po basins), and low (Islands, probably related to a thermal anomaly associated to the westward displacement of the Alboran block along the Emile Baudot escarpment 16 Ma ago. The Pn anisotropic image shows consistent orientations sub-parallel to major orogenic structures, such as Betics, Apennines, Calabrian Arc and Alps. The station delays beneath Betic and Rif ranges are strongly negative, suggesting the presence of crustal thickening all along the Gibraltar Arc. However, only the Betics have a very strong low-velocity anomaly and a pronounced anisotropy pattern. The Sn tomographic image correlates well with the Pn image, even if some relevant differences can be observed beneath particular regions.

  19. Synthesis and lithium storage properties of Zn, Co and Mg doped SnO2 Nano materials

    CSIR Research Space (South Africa)

    Palaniyandy, Nithyadharseni

    2017-09-01

    Full Text Available In this paper, we show that magnesium and cobalt doped SnO2 (Mg-SnO2 and Co-SnO2) nanostructures have profound influence on the discharge capacity and coulombic efficiency of lithium ion batteries (LIBs) employing pure SnO2 and zinc doped SnO2 (Zn-Sn...

  20. Hydrodynamical models of supernova SN 1987 A in the LMC

    International Nuclear Information System (INIS)

    Grassberg, E.K.; Imshennik, V.S.; Nadezhin, D.K.; Utrobin, V.P.

    1987-01-01

    It is shown that the properties of SN 1987A in LMC can be described well by hydrodynamical models of explosions of compact massive stars. In accordance with these models, the mass of the expelled envelope the presupernova radius and the total energy of explosion are evaluated for SN 1987A to be ∼ 16M Sun , ∼ 30R Sun , and ∼ 3.10 51 erg, respectively. The progenitor of supernova remnant Cas A may be considered as the prototype to the SN 1987A in our own Galaxy. In other galaxies, this subtype of supernovae can be represented by SN 1948B in NGC6946. If energy of explosion transfers from collapsed core of the star to the envelope within timescale less than 1 hour, then delay Δt ∼ 3 hours between the neutrino pulse and the steep rise of optical luminosity of SN 1987A does not contradict with scenario of explosions of compact massive stars