Formation of ZnO nanowires by anodization under hydrodynamic conditions for photoelectrochemical water splitting

The present work studies the influence of hydrodynamic conditions (from 0 to 5000 rpm) during Zn anodization process on the morphology, structure and photoelectrocatalytic behavior of ZnO nanostructures. For this purpose, analysis with Confocal Laser-Raman Spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and photoelectrochemical water splitting tests were performed. This investigation reveals that hydrodynamic conditions during anodization promoted the formation of ordered ZnO nanowires along the surface that greatly enhance its stability and increases the photocurrent density response for water splitting in a 159% at the 5000 rpm electrode rotation speed

Indirect charge transfer of holes via surface states in ZnO nanowires for photoelectrocatalytic applications

[EN] In this work, ZnO nanowires with high aspect ratio were obtained by fast and simple electrochemical anodization. Morphological, structural and photoelectrochemical characteristics of the synthesized ZnO nanowires were evaluated by using different techniques: field emission scanning electron microscopy, atomic force microscopy, high resolution transmission electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-VIS spectroscopy, Mott-Schottky analysis and photoelectrochemical impedance spectroscopy. The synthesized ZnO nanowires presented high roughness and high crystallinity. Besides, surface defects were identified in the sample. The value of the donor density (ND) was in the order of 1019 cm-3 in the dark and 1020 cm-3 under illumination. In addition, the ZnO nanowires presented good photosensibility, with a photocurrent density response 85 times higher than a ZnO compact layer, and lower resistance to charge transfer. The charge transfer processes taking place at the ZnO/electrolyte interface were studied, since these processes strongly influence the photoelectrocatalytic efficiency of the material. According to the results, the charge transfer of holes in the synthesized ZnO nanowires occurs indirectly via surface states. In this regard, surface states may be an important feature for photoelectrocatalytic applications since they could provide lower onset voltages and higher anodic current densities.Authors would like to express their gratitude to the Generalitat Valenciana and to the European Social Fund for their financial support within the subvention GJIDI/2018/A/067. Authors also thank to project co-funded by FEDER operational programme 2014-2020 of Comunitat Valenciana (IDIFEDER/18/044). Finally, authors thank to Ministerio de Ciencia e Innovacion-Agencia Estatal de Investigacion (PID2019-105844RB-I00/AEI/10.13039/501100011033) and MINECO for its help in the Laser Raman Microscope acquisition (UPOV08-3E-012) co -financed by the European Social Fund. Authors would also like to ex-press their gratitude for the financial support to the Generalitat Valenciana (GV/2021/011). Authors also thanks MINECO for MAT2017-84118-C2-1-R MCIN/AEI/10.13039/501100011033/project and FEDER Una manera de hacer Europa.Batista-Grau, P.; Fernández Domene, RM.; Sánchez-Tovar, R.; Blasco-Tamarit, E.; Solsona, B.; Garcia-Anton, J. (2022). Indirect charge transfer of holes via surface states in ZnO nanowires for photoelectrocatalytic applications. Ceramics International. 48(15):21856-21867. https://doi.org/10.1016/j.ceramint.2022.04.1702185621867481

Associação entre doença periodontal e aterosclerose subclínica: uma revisão sistemática Association betwenn periodontal disease and subclinic atherosclerosis: a sistematic review

A associação entre doença periodontal e o desenvolvimento de aterosclerose tem sido pesquisada. Esta revisão sistemática da literatura se propõe a verificar a associação entre a doença periodontal e a aterosclerose subclínica. A pesquisa utilizou as bases de dados: PubMed, Scopus, LILACS, BBO, Biblioteca Cochrane e Scielo com os termos: "doença periodontal", "periodontite", "carótida" e "aterosclerose". Foram excluídos artigos: que apresentaram resumos escritos em idiomas diferentes do português, inglês e espanhol; com abordagem laboratorial em modelos experimentais; sem descrição ou referência a estimadores de associação entre doença periodontal e aterosclerose subclínica; pesquisas que realizaram a medida da doença periodontal por parâmetros diferentes de exames clínicos; pesquisas que não analisaram a espessura da íntima média da artéria carótida através de exame de ultrassom; e que abordassem grupos específicos. Foram comparados os desenhos de estudo, protocolos de medida e os dados relatados. De um total de 63 referências, apenas 10 artigos contemplavam todos os critérios de inclusão, distribuídos em: 1 estudo longitudinal, 6 transversais e 3 casos controles. Observou-se uma heterogeneidade entre os estudos em relação ao método de mensuração da doença periodontal e os desfechos da aterosclerose. Concluiu-se que infecções periodontais são fortemente associadas ao desenvolvimento da aterosclerose subclínica, entretanto os mecanismos envolvidos no processo patogênico ainda permanecem desconhecidos.<br>The association between periodontal disease and the development of atherosclerosis has been studied. The systematic review of literature aims to evaluate the association between periodontal disease and subclinical atherosclerosis. A literature search of the PubMed, Scopus, LILACS, BBO, Cochrane Library and Scielo bibliographic databases was conducted using the following descriptors: "periodontal disease", "periodontitis", "carotid", and "therosclerosis". Articles were excluded if they: presented abstracts written in languages other than Portuguese, English and Spanish; experimental studies; did not contain data testing the degree of association between periodontal disease and subclinical atherosclerosis; did measure the extent of periodontal disease by parameters other than the clinical examination; did not measure the carotid artery intima-media wall thickness by ultrasonography; and covered specific population groups. The studies design, measurement protocols and reported data were compared. A total of 63 papers identified only 10 studies that met the inclusion criteria: 1 longitudinal study, 6 cross-sectional, and 3 case control studies. There was a wide heterogeneity between the studies regarding the methods of measuring periodontal disease and atherosclerosis outcomes. The conclusion is that periodontal infections are strongly associated with the development of subclinical atherosclerosis, however the mechanisms involved on the pathogenic process remain unknown