Anatase photocatalyst with supported low crystalline TiO2: The influence of amorphous phase on the activity

2018

Abstract In a previous study on commercial TiO2 nanoparticles (J. Soria et al.) we had shown that the superficial disordered layers influence their textural and reactivity features. In the present work we used well crystallized anatase particles (commercial TiO2, BDH) as support of different amounts of titania powders, prepared by TiCl4 hydrolysis and constituted by nanocrystals diluted into an amorphous matrix. The reactivity of these photocatalysts has been tested for the selective oxidation of 4-methoxybenzyl alcohol to aldehyde in aqueous suspension. The catalyst characteristics have been studied using adsorption-desorption isotherms, TEM, HRTEM, TGA, PL, DRIFT-IR, and 1H MAS-NMR spectr…

Stabilization of the rhombohedral phase in LiZr2(PO4)3 by thermal quenching

1993

Abstract Two LiZr2(PO4)3 samples, which show rhombohedral and monoclinic symmetries, have been studied by powder XRD and MAS-NMR (31P and 7Li) techniques. In the monoclinic sample phosphorus occupies three crystallographic sites and lithium is preferentially placed in M2 environment. When the samples are subjected to successive heating-quenching treatments, the rhombohedral phase is not appreciably modified while the monoclinic phase is transformed into the rhombohedral one. In the quenched samples only one site for phosphorus has been detected and occupancy of lithium in the more symmetric M1 site is favoured. After the thermal treatments, when the samples are stored at room temperature fo…

The effect of the surface disordered layer on the photoreactivity of titania nanoparticles

2017

It is well known that the surface of metal oxide catalysts presents, usually, non-crystalline species containing impurities and low coordinated cations, which are observed in HRTEM images as a disordered layer of amorphous phase. Despite of being these species more accessible and less stable than the crystalline catalysts components, they have been rarely considered when analysing the catalyst activity. In this work, we have studied the effect of a treatment with HCl solution at pH = 0 on the characteristics of the disordered layer in two commercial anatase TiO2 samples, using techniques such as TGA, 1H MAS-NMR and HRTEM, and by determining these sample photocatalytic activity for the 4-nit…

Anatase nanoparticles boundaries resulting from titanium tetrachloride hydrolysis

2017

An important factor that governs solar energy transformation into electrical or chemical energy, when using nanoparticles-based devices, is the spatial location of traps limiting electron transport. Evidences have been presented indicating that the electron diffusion is strongly influenced by nanoparticle boundaries, whose characteristics depend on the particles preparation. In the present work we have studied the role of hydrated excess proton structures in the formation of anatase nanoparticles boundaries in samples prepared by TiCl4 hydrolysis at low temperature and strong acidic conditions. The samples, constituted by anatase nanocrystals but, mainly, by amorphous titania, are studied b…

Censura, y pareceres de Dotores teologos, Canonistas, y Legistas, sobre la pretensa descomunion nulliter, promulgada, y denunciada contra don Iosef S…

En p. 80 "El Dotor Hypolito Nuñez de Auendaño" Censura, y pareceres de Dotores teologos, Canonistas, y Legistas, sobre la pretensa descomunion nulliter, promulgada, y denunciada contra don Iosef Sanz ... en confirmacion de lo que docta, y desapasionadamente se resuelue en esta alegacion, p. 81-114 Caplletra ornada Sign.: A-Ff2 Reclams

Dental stem cell signaling pathway activation in response to hydraulic calcium silicate-based endodontic cements: A systematic review of in vitro stu…

2020

Abstract Objective To present a qualitative synthesis of in vitro studies which analyzed human dental stem cell (DSC) molecular signaling pathway activation in response to hydraulic calcium silicate-based cements (HCSCs). Methods A systematic electronic search was performed in Medline, Scopus, Embase, Web of Science and SciELO databases on January 20 and last updated on March 20, 2020. In vitro studies assessing the implication of signaling pathways in activity related marker (gene/protein) expression and mineralization induced by HCSCs in contact with human DSCs were included. Results The search identified 277 preliminary results. After discarding duplicates, and screening of titles, abstr…

Acoustic, myoelectric, and aerodynamic parameters of euphonic and dysphonic voices: a systematic review of clinical studies

2021

Background: At present, there is no clinical consensus on the concept of normal and dysphonic voices. For many years, the establishment of a consensus on the terminology related to normal and pathological voices has been studied, in order to facilitate the communication between professionals in the field of the voice. Aim: systematically review the literature to compare and learn more precisely the measurable and objective characteristics of the acoustic, aerodynamic and surface electromyographic parameters of the normal and dysphonic voices. Methods: The PRISMA 2020 methodology was used as a review protocol together with the PICO procedure to answer the research question through six databa…

Por el Dotor Don Ioseph Puiasons canonigo de la Santa Iglesia de Valencia, y Vicario General Sede vacante. Con el Canonigo, y Arcediano Don Ioseph Sa…

A continuació de l'al·legació, varies opinions favorables a l'informe, amb les corresponents signatures Signada l'al·legació: "El Doct. y Pauordre Victoriano de Balda Catedratico de Prima de Canones de la presente Ciudad" Sign. : [ ]1, A-G2, H1 Reclams Port. amb grav. xil Caplletra ornada