150 research outputs found

    A transparent TMPyP/TiO2 composite thin film as an HCl sensitive optochemical gas sensor

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    Tetracationic porphyrin (TMPyP) molecules were incorporated into an optically transparent TiO2 thin film, prepared by Glancing Angle Physical Vapour Deposition (GAPVD), by simple infiltration (at pH 6.4). The preparation of optically transparent TMPyP/TiO2 composite thin films provides a method for the integration of the porphyrin molecules into photonic devices for direct monitoring of gases. Previously, UV-visible and fluorescence spectral techniques have been used to study the reversible protonation of TMPyP in aqueous solution. The optical spectrum of TMPyP shows an intense Soret band at 423 nm with a 22 nm red shift upon protonation by HCl. The experimental conditions for monitoring the concentration of HCl gas by absorption spectroscopy have been optimized. The maximum absorbance change was observed at the Soret band wavelength. A selected temperature of 80 °C and a 300 s recovery period were found to be the optimum operating parameters (response time t50 = 16.8 ± 0.7 s). The composite with smaller surface concentration of TMPyP (¿ = 0.3 × 10-9 mol cm -2) presented the best detection limit (0.1 ppm). The response of the composite sensor was highly stable for several months.Ministerio de Educación y Ciencia PET2007 0363 01/ 02, TEC201021830C0201, CSD20070000

    Differences in n-type doping efficiency between Al- and Ga-ZnO films

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    A careful and wide comparison between Al and Ga as substitutional dopants in the ZnO wurtzite structure is presented. Both cations behave as n-type dopants and their inclusion improves the optical and electrical properties of the ZnO matrix, making it more transparent in the visible range and rising up its electrical conductivity. However, the same dopant/Zn ratio leads to a very different doping efficiency when comparing Al and Ga, being the Ga cation a more effective dopant of the ZnO film. The measured differences between Al- and Ga-doped films are explained with the hypothesis that different quantities of these dopant cations are able to enter substitutionally in the ZnO matrix. Ga cations seem to behave as perfect substitutional dopants, while Al cation might occupy either substitutional or interstitial sites. Moreover, the subsequent charge balance after doping appear to be related with the formation of different intrinsic defects that depends on the dopant cation. The knowledge of the doped-ZnO films microstructure is a crucial step to optimize the deposition of transparent conducting electrodes for solar cells, displays, and other photoelectronic devices.Ministerio de Ciencia e Innovación TEC2007-60996, MAT2008-06858-C02-02, MAT2008- 06330, TEC2010-16700FUNCOAT CSD2008-00023- CONSOLIDER INGENIOSonderforschungsbereich SFB 76

    Optical gas sensing of ammonia and amines based on protonated porphyrin/TiO2 composite thin films

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    Open porous and transparent microcolumnar structures of TiO2 prepared by physical vapour deposition in glancing angle configuration (GLAD-PVD) have been used as host matrices for two different fluorescent cationic porphyrins, 5-(N-methyl 4-pyridyl)-10,15,20-triphenyl porphine chloride (MMPyP) and meso-tetra (N-methyl 4-pyridyl) porphine tetrachloride (TMPyP). The porphyrins have been anchored by electrostatic interactions to the microcolumns by self-assembly through the dip-coating method. These porphyrin/TiO2 composites have been used as gas sensors for ammonia and amines through previous protonation of the porphyrin with HCl followed by subsequent exposure to the basic analyte. UV–vis absorption, emission, and time-resolved spectroscopies have been used to confirm the protonation–deprotonation of the two porphyrins and to follow their spectral changes in the presence of the analytes. The monocationic porphyrin has been found to be more sensible (up to 10 times) than its tetracationic counterpart. This result has been attributed to the different anchoring arrangements of the two porphyrins to the TiO2 surface and their different states of aggregation within the film. Finally, there was an observed decrease of the emission fluorescence intensity in consecutive cycles of exposure and recovery due to the formation of ammonium chloride inside the film.Junta de Andalucía FQM-2310EU-FEDERMinisterio de Economía y Competitividad MAT2013-42900-P MAT2014-57652-C2-2-R MAT2015-69035-REDC MINECO-CSIC 201560E055 PCIN-2015-169-C02-0

    Evaluation of endothelial function and subclinical atherosclerosis in patients with HIV infection

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    The aim of this study was to analyse the association between human immunodefciency virus (HIV) related clinical and analytical parameters and the presence of subclinical atherosclerosis as well as endothelial dysfunction. This was a prospective cohort study of HIV-positive patients who underwent intima media thickness (IMT) determination and coronary artery calcium scoring to determine subclinical atherosclerosis. To detect endothelial dysfunction, the breath holding index, fow-mediated dilation and the concentration of endothelial progenitor cells (EPCs) were measured. Patients with an IMT? 0.9 mm had an average of 559.3 ± 283.34 CD4/?l, and those with an IMT< 0.9 mm had an average of 715.4 ± 389.92 CD4/?l (p= 0.04). Patients with a low calcium score had a signifcantly higher average CD4 cell value and lower zenith viral load (VL) than those with a higher score (707.7 ± 377.5 CD4/?l vs 477.23 ± 235.7 CD4/?l (p= 0.01) and 7 ×?¬104 ± 5 ×?¬104 copies/ml vs 23.4 × 104 ± 19 × 104 copies/ml (p= 0.02)). The number of early EPCs in patients with a CD4 nadir< 350/ µl was lower than that in those with a CD4 nadir? 350 (p= 0.03). In HIV-positive patients, low CD4 cell levels and high VL were associated with risk of developing subclinical atherosclerosis. HIV patients with CD4 cell nadir < 350/µl may have fewer early EPCs

    Characterization of the Cerdanya Neogene Basin by combining geophysical methods: passive seismic, magnetotelluric and gravimetry.

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    Congreso realizado en Toledo del 28 de noviembre al 1 de diciembre de 2022.[EN] The Cerdanya Neogene basin, located in the eastern sector of the Central Pyrenees, has been studied to characterize its structure in depth. The thickness of the Neogene filling of the basin (detrital materials with some levels of lignite) has been inferred by combining different geophysical exploration methods in a NW-SE trending profile that crosses, perpendicularly, the basin in its central part: passive seismic (H/V spectral ratio method and array technique), electromagnetic methods (MT and AMT) and gravimetry. Applying the array technique, the shear wave velocity (Vs) of the basin materials has been calculated, both for the Neogene deposits and the bedrock. These data combined with the results obtained from the H/V spectral ratio method allow deriving the bedrock geometry. The electromagnetic method provides the 2D electrical resistivity model, characterizing the geoelectric properties of the basin and depicting the presence of the d'Alp-la Tet fault, an important structural element of the basin. The electrical model inversion uses as an initial model the bedrock depth obtained from the passive seismic. In the residual Bouguer anomaly modelling, a satisfactory gravimetric model is obtained when the thickness of the Neogene deposits varies between 0 and 650 meters and assigned density of 2.2 g/cm3 , supported by the low Vs obtained. The thickness of the Neogene filling presents variations that are related to the presence of normal fault with small vertical offset. The application of this methodology, based on the combination of different geophysical exploration methods, has reduced the different uncertainties inherent in each geophysical method, and aim to characterize the Cerdanya Neogene basin geometry.Este trabajo se ha financiado con el proyecto PID2020-114273GB-C22 financiado por MCIN/AEI/10.13039/501100011033 del Ministerio de Ciencia e Innovación de España.Peer reviewe

    Subsurface Geophysics and Geology (GEOFSU

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    [EN] The geophysics line at the IGME began in 1927 as a Geophysics Sectiondedicated to subsurface exploration. During all this time, it has been developed in order to support and give expert service in all IGME’s activities both as a geological service and public research institution, as well as a research and development work itself. On the other hand, in recent years the IGME has promoted a line of research aimed at the characterization and 3D modeling of geological structures and formations, the development of dedicated software and the evolution and sophistication of computer equipment. The new scenario of incorporation of the IGME to the CSIC as a national reference center in the field of Earth Sciences has allowed the establishment of the GEOFSUB Research Group (Subsurface Geophysics and Geology). It is constituted by 21 members who had been collaborating regularly of the IGME former scientific-technic areas Geophysics and remote sensing (Área de Geofísica y Teledetección) and Subsurface geology and 3D geological modelling (Área de Geología del Subsuelo y Modelización Geológica 3D). Our main differentiating element is our extensive knowledge of geophysical and geological techniques, which allows us to characterize the subsoil in an optimal waPeer reviewe

    El aprendizaje del derecho a través de la realización de debates

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    Memoria ID-170. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2010-2011.El objetivo principal de este proyecto era conseguir que el estudiante adquiriera una serie de conocimientos a través de la preparación de un debate en el que los diferentes grupos de las diferentes asignaturas defenderían posturas contrapuestas para intentar convencer al resto de sus compañeros o al profesor de que su planteamiento es el más idóneo, no solo por la calidad de los argumentos utilizados sino también por la forma en que los mismos se han expuesto, ya que se habría formado previamente al estudiante en técnicas de expresión oral y de lenguaje verbal y no verbal

    pilotSTRATEGY project 2021-2026: “CO2 Geological Pilots in Strategic Territories”

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    [EN] The pilotSTRATEGY (2021-2026) is investigating geological CO2 storage sites in industrial regions to support development of large-scale carbon capture and storage (CCS). It is focused on deep saline aquifers–porous rock formations filled with brine several kilometres below ground – which promise a large capacity for storing captured CO2. The goal of the characterisation is to assess the site’s containment, injectivity, capacity, integrity, hydrodynamics, and monitorability in order to ensure safe and permanent storage of CO2. PilotSTRATEGY covers the initial stages of project development up to the pre-final investment decision (pre-FID), regulatory approval and permitting of storage, and applied on selected structures of Paris Basin in France, the Lusitanian Basin in Portugal and the Ebro Basin in Spain, and in lower detail, in West Macedonia in Greece and Upper Silesia in Poland.The project has received funding from the European Union’s Horizon 2020 programme (10.1 million Euros, No. 101022664).Peer reviewe
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