Control of the degradation of silica sol-gel hybrid coatings for metal implants prepared by the triple combination of alkoxysilanes

Hybrid materials obtained by sol-gel process are able to degrade and release Si compounds that are useful in regenerative medicine due to their osteoinductive properties. The present work studies the behavior of new organic-inorganic sol-gel coatings based on triple mixtures of alkoxysilanes in different molar ratios. The precursors employed are methyl-trimethoxysilane (MTMOS), 3-glycidoxypropyl-trimethoxysilane (GPTMS) and tetraethyl-orthosilicate (TEOS). After optimization of the synthesis conditions, the coatings were characterized using 29Si nuclear magnetic resonance (29Si-MNR), Fourier transform infrared spectrometry (FT-IR), contact angle measurements, hydrolytic degradation assays, electrochemical impedance spectroscopy (EIS) and mechanical profilometry. The degradation and EIS results show that by controlling the amount of TEOS precursor in the coating it is possible to tune its degradation by hydrolysis, while keeping properties such as wettability at their optimum values for biomaterials application. The corrosion properties of the new coatings were also evaluated when applied to stainless steel substrate. The coatings showed an improvement of the anticorrosive properties of the steel which is important to protect the metal implants at the early stages of the regeneration process.The financial support of MAT2014-51918-C2-2-R, P11B2014-19 and Plan de Promoción de la Investigación from the Universitat Jaume I (Predoc/2014/25) is gratefully acknowledged. J. García-Cañadas acknowledge financial support from Ramón y Cajal programme (RYC-2013-13970). The experimental support of Raquel Oliver Valls and José Ortega Herreros is also acknowledged

Tailoring The Interface Using Thiophene Small Molecules In Tio 2/p3ht Hybrid Solar Cells

In this paper we focus on the effect of carboxylated thiophene small molecules as interface modifiers in TiO 2/P3HT hybrid solar cells. Our results show that small differences in the chemical structure of these molecules, for example, the presence of the -CH 2- group in the 2-thiopheneacetic acid (TAA), can greatly increase the TiO 2 surface wettability, improving the TiO 2/polymer contact. This effect is important to enhance exciton splitting and charge separation. This journal is © 2012 the Owner Societies.14341199011993Huang, Y.-C., Hsu, J.-H., Liao, Y.-C., Yen, W.-C., Li, S.-S., Lin, S.-T., Chen, C.-W., Su, W.-F., (2011) J. Mater. Chem., 21, p. 4450Bouclé, J., Ravirajan, P., Nelson, J., (2007) J. Mater. Chem., 17, p. 3141Bhongale, C.J., Thelakkat, M., (2010) Sol. Energy Mater. Sol. Cells, 94, p. 817Bolognesi, M., Sánchez-Díaz, A., Ajuria, J., Pacios, R., Palomares, E., (2011) Phys. Chem. Chem. Phys., 13, p. 6105Arici, E., Meissner, D., Schaffler, F., Sariciftci, N.S., (2003) Int. J. Photoenergy, 5, p. 199Arici, E., Sariciftci, N.S., Meissner, D., (2003) Adv. Funct. Mater., 13, p. 165De Freitas, J.N., Grova, I.R., Akcelrud, L.C., Arici, E., Sariciftcic, N.S., Nogueira, A.F., (2010) J. Mater. Chem., 20, p. 4845Yella, A., Lee, H.-W., Tsao, H.N., Yi, C., Chandiran, A.K., Nazeeruddin, M.K., Diau, E.W.-G., Grätzel, M., (2011) Science, 334, p. 629Yu, Q., Wang, Y., Yi, Z., Zu, N., Zhang, J., Zhang, M., Wang, P., (2010) ACS Nano, 4, p. 6032Lin, Y.-Y., Chu, T.-H., Li, S.-S., Chuang, C.-H., Chang, C.-H., Su, W.-F., Chang, C.-P., Chen, C.-W., (2009) J. Am. Chem. Soc., 131, p. 3644Sun, Z., Li, J., Liu, C., Yang, S., Yan, F., (2011) Adv. Mater., 23, p. 3648Coakley, K.M., Srinvasan, B.S., Ziebarth, J.M., Goh, C., Liu, Y.X., McGehee, M.D., (2005) Adv. Funct. Mater., 15, p. 1927Huang, Y.-C., Yen, W.-C., Liao, Y.-C., Yu, Y.-C., Hsu, C.-C., Ho, M.-L., Chou, P.-T., Su, W.-F., (2010) Appl. Phys. Lett., 96, p. 123501Zhang, W., Zhu, R., Li, F., Wang, Q., Liu, B., (2011) J. Phys. Chem. C, 115, p. 7038Johansson, E.M.J., Scholin, R., Siegbahn, H., Hagfeldt, A., Rensmo, H., (2011) Chem. Phys. Lett., 515, p. 146Ravirajan, P., Peiró, A.M., Nazeeruddin, M.K., Grätzel, M., Bradley, D.D.C., Durrant, J.R., Nelson, J., (2006) J. Phys. Chem. B, 110, p. 7635Weickert, J., Dunbar, R.B., Hesse, H.C., Wiedemann, W., Mende, L.S., (2011) Adv. Mater., 23, p. 1810Chang, J.A., Rhee, J.H., Im, S.H., Lee, Y.H., Kim, H.-J., Seok, S.I., Nazeeruddin, M.K., Gratzel, M., (2010) Nano Lett., 10, p. 2609Jiang, X., Karlsson, K.M., Gabrielsson, E., Johansson, E.M.J., Quintana, M., Karlsson, M., Sun, L., Hagfeldt, A., (2011) Adv. Funct. Mater., 21, p. 2944Snaith, H.J., Moule, A.J., Klein, C., Meerholz, K., Friend, R.H., Grätzel, M., (2007) Nano Lett., 7, p. 3372Weickert, J., Auras, F., Bein, T., Mende, L.S., (2011) J. Phys. Chem. C, 115, p. 15081Liu, Y., Scully, S.R., McGehee, M.D., Liu, J., Luscombe, C.K., Frechet, J.M.J., Shaheen, S.E., Ginley, D.S., (2006) J. Phys. Chem. B, 110, p. 3257Chang, Y.-M., Su, W.-F., Wang, L., (2008) Macromol. Rapid Commun., 29, p. 1303Cantu, M.L., Chafiq, A., Faissat, J., Valls, I.G., Yu, Y., (2011) Sol. Energy Mater. Sol. Cells, 95, p. 1362Jiang, K.-J., Manseki, K., Yu, Y.-H., Masaki, N., Suzuki, K., Suzuki, Y.-L., Yanagida, S., (2009) Adv. Funct. Mater., 19, p. 2481Goh, C., Scully, S.R., McGehee, M.D., (2007) J. Appl. Phys., 101, p. 114503Krüger, J., Bach, U., Grätzel, M., (2000) Adv. Mater., 12, p. 447Montanari, I., Nogueira, A.F., Nelson, J., Durrant, J.R., Winder, C., Loi, M.A., Sariciftci, N.S., Brabec, C., (2002) Appl. Phys. Lett., 81, p. 3001Nogueira, A.F., Montanari, I., Nelson, J., Brabec, C., Sariciftci, N.S., Durrant, J.R., (2003) J. Phys. Chem., 107, p. 1567Haque, S.A., Palomares, E., Cho, B.M., Green, A.N.M., Hirata, N., Klug, D.R., Durrant, J.R., (2005) J. Am. Chem. Soc., 127, p. 3456Clifford, J.N., Palomares, E., Nazeeruddin, M.K., Grätzel, M., Nelson, J., Li, X., Long, J., Durrant, J.R., (2004) J. Am. Chem. Soc., 126, p. 5225Bouclé, J., Chyla, S., Shaffer, M.S.P., Durrant, J.R., Bradley, D.D.C., Nelson, J., (2008) Adv. Funct. Mater., 18, p. 62

Superconducting gap node spectroscopy using nonlinear electrodynamics

We present a method to determine the nodal structure of the energy gap of unconventional superconductors such as high $T_c$ materials. We show how nonlinear electrodynamics phenomena in the Meissner regime, arising from the presence of lines on the Fermi surface where the superconducting energy gap is very small or zero, can be used to perform ``node spectroscopy'', that is, as a sensitive bulk probe to locate the angular position of those lines. In calculating the nonlinear supercurrent response, we include the effects of orthorhombic distortion and $a-b$ plane anisotropy. Analytic results presented demonstrate a systematic way to experimentally distinguish order parameters of different symmetries, including cases with mixed symmetry (for example, $d+s$ and $s+id$). We consider, as suggested by various experiments, order parameters with predominantly $d$-wave character, and describe how to determine the possible presence of other symmetries. The nonlinear magnetic moment displays a distinct behavior if nodes in the gap are absent but regions with small, finite, values of the energy gap exist.Comment: 18 pages, Revtex, 9 postscript figures. Submitted to Phys. Rev

Large Scale Morphological Segregation in Optically Selected Galaxy Redshift Catalogs

We present the results of an exhaustive analysis of the morphological segregation of galaxies in the CfA and SSRS catalogs through the scaling formalism. Morphological segregation between ellipticals and spirals has been detected at scales up to 15-20 h$^{-1}$ Mpc in the CfA catalog, and up to 20-30 h$^{-1}$ Mpc in the SSRS catalog. Moreover, it is present not only in the densest areas of the galaxy distribution, but also in zones of moderate density.Comment: 9 pages, (1 figure included), uuencode compressed Postscript, (accepted for publication in ApJ Letters), FTUAM-93-2

Pere Vieta (1779–1856), promoter of free public teaching of physics in Catalonia

Free public teaching of physics in Catalonia started in the early 19th century, even if the interest in experimental physics goes back to the 18th century, where this discipline was discussed at various learned societies. The first chair of Physics in Barcelona was not a university chair but that of the Junta de Comerç de Barcelona (Trade Board of Barcelona), which had several scientific-technical Schools. In fact, at that time, Barcelona had no university, because it had been supressed by King Felipe V after the War of the Spanish Succession (ended in 1714). The promoter of free public teaching of experimental physics was Pere (Pedro) Vieta i Gibert (17791856), who was the first professor of that subject both at the School of the Trade Board and at the University of Barcelona, once it was restored in 1842. Vieta, who was a surgeon in the Army, combined his two professions and his interest in meteorology, he having recorded meteorological observations in Barcelona for many years. Many of his students were influential people in the scientific, intellectual, political and economic history of the 19th century in Catalonia and Spain. [Contrib Sci 11:237-247 (2015)]Postprint (published version

Flux Lattice Melting and Lowest Landau Level Fluctuations

We discuss the influence of lowest Landau level (LLL) fluctuations near H_{c2}(T) on flux lattice melting in YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO). We show that the specific heat step of the flux lattice melting transition in YBCO single crystals can be attributed largely to the degrees of freedom associated with LLL fluctuations. These degrees of freedom have already been shown to account for most of the latent heat. We also show that these results are a consequence of the correspondence between flux lattice melting and the onset of LLL fluctuations.Comment: 4 pages, 2 embedded figure

Formes i modelats glacials i periglacials al Pirineu Oriental

This is a geomorphological study of the river Segre's upper section, including the mountains of Calmquerdos, Tossa Plana de Lles and Port Negre, situated between the valleys of the rivers Valira and Querol (Eastern Pyrenees). The morphogenetic dynamics of quaternary glaciarism have been noted, clearly distinguishing two glacial episodes: one main impulse corresponding with the moraines farther away from the cirques'heads, and a minimal extension reflected by the rock glaciers fixed in the glacial basins. The past action of the periglacial morphoclimatic system has also been discussed, marking the importance that it had in the remodelation of the glacial forms and the slopes below. The paper closes with the study of the actual geomorphological dynamics operating in the supraforestal levels of the mountains in the upper part of the river Segre's Valley. A special attention has been taken in emphasizing the periglacial action on the spatial distribution of the various modellings that give form to those levels