583 research outputs found

    Observation of asymmetric spectrum broadening induced by silver nanoparticles in a heavy-metal oxide glass

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    We demonstrate experimentally and support by a theoretical analysis an effect of asymmetric spectrum broadening, which results from doping of silver nanoparticles into a heavy-glass matrix, 90(0.5WO3-0.3SbPO4-0.2PbO)-10AgCl. The strong dispersion of the effective nonlinear coefficient of the composite significantly influences the spectral broadening via the self-phase modulation, and leads to a blue upshift of the spectrum. Further extension of the spectrum towards shorter wavelengths is suppressed by a growing loss caused by the plasmon resonance in the silver particles. The red-edge spectral broadening is dominated by the stimulated Raman Scattering.Comment: Accepted for publishing epl13477; EPL Journal 201

    A Technology Pathway for Airbreathing, Combined-Cycle, Horizontal Space Launch Through SR-71 Based Trajectory Modeling

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    Access to space is in the early stages of commercialization. Private enterprises, mainly under direct or indirect subsidy by the government, have been making headway into the LEO launch systems infrastructure, of small-weight-class payloads of approximately 1000 lbs. These moderate gains have emboldened the launch industry and they are poised to move into the middle-weight class (roughly 5000 lbs). These commercially successful systems are based on relatively straightforward LOX-RP, two-stage, bi-propellant rocket technology developed by the government 40 years ago, accompanied by many technology improvements. In this paper we examine a known generic LOX-RP system with the focus on the booster stage (1st stage). The booster stage is then compared to modeled Rocket-Based and Turbine-Based Combined Cycle booster stages. The air-breathing propulsion stages are based on/or extrapolated from known performance parameters of ground tested RBCC (the Marquardt Ejector Ramjet) and TBCC (the SR-71/J-58 engine) data. Validated engine models using GECAT and SCCREAM are coupled with trajectory optimization and analysis in POST-II to explore viable launch scenarios using hypothetical aerospaceplane platform obeying the aerodynamic model of the SR-71. Finally, and assessment is made of the requisite research technology advances necessary for successful commercial and government adoption of combined-cycle engine systems for space access

    Resíduos sólidos de uva e compostos com capacidade oxi-redox favorável.

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    O objetivo deste estudo foi determinar a diferença existente entre os resíduos dos cultivares Isabel, Niágara, Chardonnay, Pinot Noir e uma mistura de cultivares em relação à concentração dos agentes oxi-redoxf para exploração industrial e comercial.Resumo

    Lens connexins α3Cx46 and α8Cx50 interact with zonula occludens protein-1 (ZO-1)

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    Connexin α1Cx43 has previously been shown to bind to the PDZ domain–containing protein ZO-1. The similarity of the carboxyl termini of this connexin and the lens fiber connexins α3Cx46 and α8Cx50 suggested that these connexins may also interact with ZO-1. ZO-1 was shown to be highly expressed in mouse lenses. Colocalization of ZO-1 with α3Cx46 and α8Cx50 connexins in fiber cells was demonstrated by immunofluorescence and by fracture-labeling electron microscopy but showed regional variations throughout the lens. ZO-1 was found to coimmunoprecipitate with α3Cx46 and α8Cx50, and pull-down experiments showed that the second PDZ domain of ZO-1 was involved in this interaction. Transiently expressed α3Cx46 and α8Cx50 connexins lacking the COOH-terminal residues did not bind to the second PDZ domain but still formed structures resembling gap junctions by immunofluorescence. These results indicate that ZO-1 interacts with lens fiber connexins α3Cx46 and α8Cx50 in a manner similar to that previously described for α1Cx43. The spatial variation in the interaction of ZO-1 with lens gap junctions is intriguing and is suggestive of multiple dynamic roles for this association

    Structural and vibrational study of cubic Sb2O3 under high pressure

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    We report an experimental and theoretical study of antimony oxide (Sb 2O 3) in its cubic phase (senarmontite) under high pressure. X-ray diffraction and Raman scattering measurements up to 18 and 25 GPa, respectively, have been complemented with ab initio total-energy and lattice-dynamics calculations. X-ray diffraction measurements do not provide evidence of a space-group symmetry change in senarmontite up to 18 GPa. However, Raman scattering measurements evidence changes in the pressure coefficients of the Raman mode frequencies at 3.5 and 10 GPa, respectively. The behavior of the Raman modes with increasing pressure up to 25 GPa is fully reproduced by the lattice-dynamics calculations in cubic Sb 2O 3. Therefore, the combined analysis of both experiments and lattice-dynamics calculations suggest the occurrence of two isostructural phase transformations at 3.5 and 10 GPa, respectively. Total-energy calculations show that the isostructural phase transformations occur through local atomic displacements in which senarmontite loses its molecular character to become a three-dimensional solid. In addition, our calculations provide evidence that cubic senarmontite cannot undergo a phase transition to orthorhombic valentinite at high pressure, and that a phase transition to a ß-Bi 2O 3-type structure is possible above 25 GPa. © 2012 American Physical Society.Financial support from the Spanish Consolider Ingenio 2010 Program (Project No. CDS2007-00045) is acknowledged. The work was also supported by Spanish MICCIN under Projects No. CTQ2009-14596-C02-01 and No. MAT2010-21270-C04-01/04 as well as from Comunidad de Madrid and European Social Fund, S2009/PPQ-1551 4161893 (QUIMAPRES) and from Vicerrectorado de Investigacion de la Universitat Politecnica de Valencia under projects UPV2011-0914 PAID-05-11 and UPV2011-0966 PAID-06-11. Spanish Fundacio Bancaixa Project No. P1-1A2009-08 and Brazilian Capes/Fundacion Carolina (BEX 3939/10-3) are also acknowledged.Pereira, ALJ.; Gracia, L.; Santamaría-Pérez, D.; Vilaplana Cerda, RI.; Manjón Herrera, FJ.; Errandonea, D.; Nalin, M.... (2012). Structural and vibrational study of cubic Sb2O3 under high pressure. Physical Review B. 85(17):174108-1-174108-11. https://doi.org/10.1103/PhysRevB.85.174108S174108-1174108-118517Youk, J. H., Kambour, R. P., & MacKnight, W. J. (2000). Polymerization of Ethylene Terephthalate Cyclic Oligomers with Antimony Trioxide†. Macromolecules, 33(10), 3594-3599. doi:10.1021/ma991838dZabinski, J. S., Donley, M. S., & McDevitt, N. T. (1993). Mechanistic study of the synergism between Sb2O3 and MoS2 lubricant systems using Raman spectroscopy. Wear, 165(1), 103-108. doi:10.1016/0043-1648(93)90378-yGhosh, A., & Chakravorty, D. (1991). Transport properties of semiconducting CuO-Sb2O3-P2O5glasses. Journal of Physics: Condensed Matter, 3(19), 3335-3342. doi:10.1088/0953-8984/3/19/012Gopalakrishnan, P. S., & Manohar, H. (1975). Kinetics and mechanism of the transformation in antimony trioxide from orthorhombic valentinite to cubic senarmontite. Journal of Solid State Chemistry, 15(1), 61-67. doi:10.1016/0022-4596(75)90271-6Zachariasen, W. H. (1932). THE ATOMIC ARRANGEMENT IN GLASS. Journal of the American Chemical Society, 54(10), 3841-3851. doi:10.1021/ja01349a006Matsumoto, A., Koyama, Y., Togo, A., Choi, M., & Tanaka, I. (2011). Electronic structures of dynamically stable As2O3, Sb2O3, and Bi2O3crystal polymorphs. Physical Review B, 83(21). doi:10.1103/physrevb.83.214110Miller, P. J., & Cody, C. A. (1982). Infrared and Raman investigation of vitreous antimony trioxide. Spectrochimica Acta Part A: Molecular Spectroscopy, 38(5), 555-559. doi:10.1016/0584-8539(82)80146-3Svensson, C. (1975). Refinement of the crystal structure of cubic antimony trioxide, Sb2O3. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 31(8), 2016-2018. doi:10.1107/s0567740875006759Wood, C., van Pelt, B., & Dwight, A. (1972). The Optical Properties of Amorphous and Crystalline Sb2O3. Physica Status Solidi (b), 54(2), 701-706. doi:10.1002/pssb.2220540234Nalin, M., Messaddeq, Y., Ribeiro, S. J. L., Poulain, M., Briois, V., Brunklaus, G., … Eckert, H. (2004). Structural organization and thermal properties of the Sb2O3–SbPO4glass system. J. Mater. Chem., 14(23), 3398-3405. doi:10.1039/b406075jOrosel, D., Dinnebier, R. E., Blatov, V. A., & Jansen, M. (2012). Structure of a new high-pressure–high-temperature modification of antimony(III) oxide, γ-Sb2O3, from high-resolution synchrotron powder diffraction data. Acta Crystallographica Section B Structural Science, 68(1), 1-7. doi:10.1107/s0108768111046751Grzechnik, A. (1999). Compressibility and Vibrational Modes in Solid As4O6. Journal of Solid State Chemistry, 144(2), 416-422. doi:10.1006/jssc.1999.8189Soignard, E., Amin, S. A., Mei, Q., Benmore, C. J., & Yarger, J. L. (2008). High-pressure behavior ofAs2O3: Amorphous-amorphous and crystalline-amorphous transitions. Physical Review B, 77(14). doi:10.1103/physrevb.77.144113Chouinard, C., & Desgreniers, S. (1999). Bi2O3 under hydrostatic pressure: observation of a pressure-induced amorphization. Solid State Communications, 113(3), 125-129. doi:10.1016/s0038-1098(99)00463-9Geng, A., Cao, L., Wan, C., & Ma, Y. (2011). High-pressure Raman investigation of the semiconductor antimony oxide. physica status solidi (c), 8(5), 1708-1711. doi:10.1002/pssc.201000786Manjón, F. J., & Errandonea, D. (2009). Pressure-induced structural phase transitions in materials and earth sciences. physica status solidi (b), 246(1), 9-31. doi:10.1002/pssb.200844238Mao, H. K., Xu, J., & Bell, P. M. (1986). Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions. Journal of Geophysical Research, 91(B5), 4673. doi:10.1029/jb091ib05p04673Rodríguez-Carvajal, J. (1993). Recent advances in magnetic structure determination by neutron powder diffraction. Physica B: Condensed Matter, 192(1-2), 55-69. doi:10.1016/0921-4526(93)90108-iErrandonea, D., Santamaria-Perez, D., Bondarenko, T., & Khyzhun, O. (2010). New high-pressure phase of HfTiO4 and ZrTiO4 ceramics. Materials Research Bulletin, 45(11), 1732-1735. doi:10.1016/j.materresbull.2010.06.061Errandonea, D., Santamaria-Perez, D., Achary, S. N., Tyagi, A. K., Gall, P., & Gougeon, P. (2011). High-pressure x-ray diffraction study of CdMoO4 and EuMoO4. Journal of Applied Physics, 109(4), 043510-043510-5. doi:10.1063/1.3553850Stroppa, D. G., Montoro, L. A., Beltrán, A., Conti, T. G., da Silva, R. O., Andrés, J., … Ramirez, A. J. (2009). Unveiling the Chemical and Morphological Features of Sb−SnO2Nanocrystals by the Combined Use of High-Resolution Transmission Electron Microscopy and ab Initio Surface Energy Calculations. Journal of the American Chemical Society, 131(40), 14544-14548. doi:10.1021/ja905896uBecke, A. D. (1993). Density‐functional thermochemistry. III. The role of exact exchange. The Journal of Chemical Physics, 98(7), 5648-5652. doi:10.1063/1.464913Lee, C., Yang, W., & Parr, R. G. (1988). Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Physical Review B, 37(2), 785-789. doi:10.1103/physrevb.37.785Beltrán, A., Gracia, L., & Andrés, J. (2006). Density Functional Theory Study of the Brookite Surfaces and Phase Transitions between Natural Titania Polymorphs. The Journal of Physical Chemistry B, 110(46), 23417-23423. doi:10.1021/jp0643000Grimme, S. (2006). Semiempirical GGA-type density functional constructed with a long-range dispersion correction. Journal of Computational Chemistry, 27(15), 1787-1799. doi:10.1002/jcc.20495Bučko, T., Hafner, J., Lebègue, S., & Ángyán, J. G. (2010). Improved Description of the Structure of Molecular and Layered Crystals: Ab Initio DFT Calculations with van der Waals Corrections. The Journal of Physical Chemistry A, 114(43), 11814-11824. doi:10.1021/jp106469xBirch, F. (1952). Elasticity and constitution of the Earth’s interior. Journal of Geophysical Research, 57(2), 227-286. doi:10.1029/jz057i002p00227Whitten, A. E., Dittrich, B., Spackman, M. A., Turner, P., & Brown, T. C. (2004). Charge density analysis of two polymorphs of antimony(iii) oxide. Dalton Transactions, (1), 23. doi:10.1039/b312550eKroumova, E., Aroyo, M. I., Perez-Mato, J. M., Kirov, A., Capillas, C., Ivantchev, S., & Wondratschek, H. (2003). Bilbao Crystallographic Server : Useful Databases and Tools for Phase-Transition Studies. Phase Transitions, 76(1-2), 155-170. doi:10.1080/0141159031000076110Cody, C. A., DiCarlo, L., & Darlington, R. K. (1979). Vibrational and thermal study of antimony oxides. Inorganic Chemistry, 18(6), 1572-1576. doi:10.1021/ic50196a036Gilliam, S. J., Jensen, J. O., Banerjee, A., Zeroka, D., Kirkby, S. J., & Merrow, C. N. (2004). A theoretical and experimental study of Sb4O6: vibrational analysis, infrared, and Raman spectra. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 60(1-2), 425-434. doi:10.1016/s1386-1425(03)00245-2Mestl, G., Ruiz, P., Delmon, B., & Knozinger, H. (1994). Sb2O3/Sb2O4 in reducing/oxidizing environments: an in situ Raman spectroscopy study. The Journal of Physical Chemistry, 98(44), 11276-11282. doi:10.1021/j100095a008Blower, S. K., & Greaves, C. (1988). The structure of β-Bi2O3 from powder neutron diffraction data. Acta Crystallographica Section C Crystal Structure Communications, 44(4), 587-589. doi:10.1107/s0108270187011661Johansson, B., & Li, S. (2009). Itinerantf-electron elements. Philosophical Magazine, 89(22-24), 1793-1799. doi:10.1080/14786430902917632Akahama, Y., Kobayashi, M., & Kawamura, H. (1991). High-Pressure X-Ray Diffraction Study on Electronics-dTransition in Zirconium. Journal of the Physical Society of Japan, 60(10), 3211-3214. doi:10.1143/jpsj.60.3211Occelli, F., Farber, D. L., Badro, J., Aracne, C. M., Teter, D. M., Hanfland, M., … Couzinet, B. (2004). Experimental Evidence for a High-Pressure Isostructural Phase Transition in Osmium. Physical Review Letters, 93(9). doi:10.1103/physrevlett.93.095502Zarechnaya, E., Dubrovinskaia, N., Caracas, R., Merlini, M., Hanfland, M., Filinchuk, Y., … Dubrovinsky, L. (2010). Pressure-induced isostructural phase transformation inγ-B28. Physical Review B, 82(18). doi:10.1103/physrevb.82.184111Chatterjee, A., Singh, A. K., & Jayaraman, A. (1972). Pressure-Induced Electronic Collapse and Structural Changes in Rare-Earth Monochalcogenides. Physical Review B, 6(6), 2285-2291. doi:10.1103/physrevb.6.2285Chefki, M., Abd-Elmeguid, M. M., Micklitz, H., Huhnt, C., Schlabitz, W., Reehuis, M., & Jeitschko, W. (1998). Pressure-induced Transition of the Sublattice Magnetization inEuCo2P2: Change from Local MomentEu(4f)to ItinerantCo(3d)Magnetism. Physical Review Letters, 80(4), 802-805. doi:10.1103/physrevlett.80.802Caracas, R., & Gonze, X. (2004). Structural, electronic, and dynamical properties of calaveriteAuTe2under pressure. Physical Review B, 69(14). doi:10.1103/physrevb.69.144114Svane, A., Strange, P., Temmerman, W. M., Szotek, Z., Winter, H., & Petit, L. (2001). Pressure-Induced Valence Transitions in Rare Earth Chalcogenides and Pnictides. physica status solidi (b), 223(1), 105-116. doi:10.1002/1521-3951(200101)223:13.0.co;2-iYoo, C. S., Maddox, B., Klepeis, J.-H. P., Iota, V., Evans, W., McMahan, A., … Pickett, W. E. (2005). First-Order Isostructural Mott Transition in Highly Compressed MnO. Physical Review Letters, 94(11). doi:10.1103/physrevlett.94.115502Rosner, H., Koudela, D., Schwarz, U., Handstein, A., Hanfland, M., Opahle, I., … Richter, M. (2006). Magneto-elastic lattice collapse in YCo5. Nature Physics, 2(7), 469-472. doi:10.1038/nphys341Polian, A., Gauthier, M., Souza, S. M., Trichês, D. M., Cardoso de Lima, J., & Grandi, T. A. (2011). Two-dimensional pressure-induced electronic topological transition in Bi2Te3. Physical Review B, 83(11). doi:10.1103/physrevb.83.113106Vilaplana, R., Gomis, O., Manjón, F. J., Segura, A., Pérez-González, E., Rodríguez-Hernández, P., … Kucek, V. (2011). High-pressure vibrational and optical study of Bi2Te3. Physical Review B, 84(10). doi:10.1103/physrevb.84.104112Vilaplana, R., Santamaría-Pérez, D., Gomis, O., Manjón, F. J., González, J., Segura, A., … Kucek, V. (2011). Structural and vibrational study of Bi2Se3under high pressure. Physical Review B, 84(18). doi:10.1103/physrevb.84.184110Sakai, N., Kajiwara, T., Takemura, K., Minomura, S., & Fujii, Y. (1981). Pressure-induced phase transition in Sb2Te3. Solid State Communications, 40(12), 1045-1047. doi:10.1016/0038-1098(81)90248-9Souza, S. M., Trichês, D. M., Poffo, C. M., de Lima, J. C., Grandi, T. A., & de Biasi, R. S. (2011). Structural, thermal, optical, and photoacoustic study of nanocrystalline Bi2Te3 produced by mechanical alloying. Journal of Applied Physics, 109(1), 013512. doi:10.1063/1.3520658Åberg, D., Erhart, P., Crowhurst, J., Zaug, J. M., Goncharov, A. F., & Sadigh, B. (2010). Pressure-induced phase transition in the electronic structure of palladium nitride. Physical Review B, 82(10). doi:10.1103/physrevb.82.10411

    Altered two-dimensional strain measures of the right ventricle in patients with Brugada syndrome and arrhythmogenic right ventricular dysplasia/cardiomyopathy

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    Aims: Brugada syndrome (BrS) is an inherited channelopathy that can be characterized by mild right ventricular (RV) abnormalities that are not detectable with conventional echocardiography. The aim of this study was to evaluate the presence of RV abnormalities in BrS patients when compared with controls and a group of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) using two-dimensional (2D) strain analysis. Methods and results: We enrolled 25 BrS, 15 ARVD/C patients, and 25 controls. Right and left ventricular dimension and systo-diastolic function were evaluated by conventional echocardiography. Longitudinal systolic strain (sS) peak, systolic and early diastolic strain rate of lateral RV segments were evaluated by 2D speckle tracking analysis. Left ventricle global and segmental strain measures were also evaluated. A reduced basal or mid-RV lateral sS were the parameters mostly associated with both BrS and ARVD/C. In BrS patients the minimum sS observed in these segments was significantly lower than that of controls (-28.9±3.2% vs. -32.3±3.2%, P: 0.002) but significantly greater than that evaluated in ARVD/C patients (-24.6 ±6.7%, P < 0.001 both vs. BrS and controls). No differences were found between the BrS and the control group when left ventricular strain measures were analysed. Conclusion: By 2D strain technique it is possible to observe mild abnormalities in RV systolic and diastolic function of BrS patients that are less pronounced than those observed in ARVD/C patients. These results help to better define the phenotypic characteristics of BrS patients and represent the basis for future studies aimed at testing their clinical usefulness in BrS patients

    Genetic diversity of Mycobacterium tuberculosis in Peru and exploration of phylogenetic associations with drug resistance.

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    BACKGROUND: There is limited available data on the strain diversity of M tuberculosis in Peru, though there may be interesting lessons to learn from a setting where multidrug resistant TB has emerged as a major problem despite an apparently well-functioning DOTS control programme. METHODS: Spoligotyping was undertaken on 794 strains of M tuberculosis collected between 1999 and 2005 from 553 community-based patients and 241 hospital-based HIV co-infected patients with pulmonary tuberculosis in Lima, Peru. Phylogenetic and epidemiologic analyses permitted identification of clusters and exploration of spoligotype associations with drug resistance. RESULTS: Mean patient age was 31.9 years, 63% were male and 30.4% were known to be HIV+. Rifampicin mono-resistance, isoniazid mono-resistance and multidrug resistance (MDR) were identified in 4.7%, 8.7% and 17.3% of strains respectively. Of 794 strains from 794 patients there were 149 different spoligotypes. Of these there were 27 strains (3.4%) with novel, unique orphan spoligotypes. 498 strains (62.7%) were clustered in the nine most common spoligotypes: 16.4% SIT 50 (clade H3), 12.3% SIT 53 (clade T1), 8.3% SIT 33 (LAM3), 7.4% SIT 42 (LAM9), 5.5% SIT 1 (Beijing), 3.9% SIT 47 (H1), 3.0% SIT 222 (clade unknown), 3.0% SIT1355 (LAM), and 2.8% SIT 92 (X3). Amongst HIV-negative community-based TB patients no associations were seen between drug resistance and specific spoligotypes; in contrast HIV-associated MDRTB, but not isoniazid or rifampicin mono-resistance, was associated with SIT42 and SIT53 strains. CONCLUSION: Two spoligotypes were associated with MDR particularly amongst patients with HIV. The MDR-HIV association was significantly reduced after controlling for SIT42 and SIT53 status; residual confounding may explain the remaining apparent association. These data are suggestive of a prolonged, clonal, hospital-based outbreak of MDR disease amongst HIV patients but do not support a hypothesis of strain-specific propensity for the acquisition of resistance-conferring mutations
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