93 research outputs found

    Chemical pressure effect on the optical conductivity of the nodal-line semimetals ZrSiYY (YY=S, Se, Te) and ZrGeYY (YY=S, Te)

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    ZrSiS is a nodal-line semimetal, whose electronic band structure contains a diamond-shaped line of Dirac nodes. We carried out a comparative study on the optical conductivity of ZrSiS and related compounds ZrSiSe, ZrSiTe, ZrGeS, and ZrGeTe by reflectivity measurements over a broad frequency range combined with density functional theory calculations. The optical conductivity exhibits a distinct U shape, ending at a sharp peak at around 10000~cm−1^{-1} for all studied compounds, except for ZrSiTe. The U shape of the optical conductivity is due to transitions between the linearly dispersing bands crossing each other along the nodal line. The sharp high-energy peak is related to transitions between almost parallel bands, and its energy position depends on the interlayer bonding correlated with the cc/aa ratio, which can be tuned by either chemical or external pressure. For ZrSiTe, another pair of crossing bands appears in the vicinity of the Fermi level, corrugating the nodal-line electronic structure and leading to the observed difference in optical conductivity. The findings suggest that the Dirac physics in ZrXYXY compounds with XX=Si, Ge and YY=S, Se, Te is closely connected to the interlayer bonding.Comment: 9 pages, 6 figure

    Remote activation of enzyme nanohybrids for cancer prodrug therapy controlled by magnetic heating

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    Herein, we have developed nanohybrids (nHs) to remotely activate a therapeutic enzyme for its use in Directed Enzyme Prodrug Therapy (DEPT). The coencapsulation of magnetic nanoparticles (MNPs) with horseradish peroxidase (HRP) using biomimetic silica as an entrapment matrix was optimized to obtain nanosized hybrids (∌150 nm) for remote activation of the therapeutic enzyme. HRP converts indole-3-acetic acid (3IAA) into peroxylated radicals, whereas MNPs respond to alternating magnetic fields (AMFs) becoming local hotspots. The AMF application triggered an increase in the bioconversion rate of HRP matching the activity displayed at the optimal temperature of the nHs (Topt = 50 °C) without altering the temperature of the reaction media. This showed that enzyme nanoactuation is possible with MNPs even if they are not covalently bound. After an extensive physicochemical/magnetic characterization, the spatial location of each component of the nH was deciphered, and an insulating role of the silica matrix was suggested as critical for introducing remote control over HRP. In vitro assays, using a human pancreatic cancer cell line (MIA PaCa-2), showed that only upon exposure to AMF and in the presence of the prodrug, the enzyme-loaded nHs triggered cell death. Moreover, in vivo experiments showed higher reductions in the tumor volume growth in those animals treated with nHs in the presence of 3IAA when exposed to AMF. Thus, this work demonstrates the feasibility of developing a spatiotemporally controlled DEPT strategy to overcome unwanted off-target effects

    Iron–Gold Nanoflowers: A Promising Tool for Multimodal Imaging and Hyperthermia Therapy

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    The development of nanoplatforms prepared to perform both multimodal imaging and combined therapies in a single entity is a fast-growing field. These systems are able to improve diagnostic accuracy and therapy success. Multicomponent Nanoparticles (MCNPs), composed of iron oxide and gold, offer new opportunities for Magnetic Resonance Imaging (MRI) and Computed To-mography (CT) diagnosis, as well as combined therapies based on Magnetic Hyperthermia (MH) and Photothermal Therapy (PT). In this work, we describe a new seed-assisted method for the synthesis of Au@Fe Nanoparticles (NPs) with a flower-like structure. For biomedical purposes, Au@Fe NPs were functionalized with a PEGylated ligand, leading to high colloidal stability. Moreover, the as-obtained Au@Fe-PEG NPs exhibited excellent features as both MRI and CT Contrast Agents (CAs), with high r2 relaxivity (60.5 mM-1·s-1 ) and X-ray attenuation properties (8.8 HU mM-1·HU). In addition, these nanoflowers presented considerable energy-to-heat conversion under both Alternating Magnetic Fields (AMFs) (ÂżT ˜ 2.5ÂżC) and Near-Infrared (NIR) light (ÂżT ˜ 17ÂżC). Finally, Au@Fe-PEG NPs exhibited very low cytotoxicity, confirming their potential for theranostics applications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

    Shiga Toxin 1 Induces on Lipopolysaccharide-Treated Astrocytes the Release of Tumor Necrosis Factor-alpha that Alter Brain-Like Endothelium Integrity

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    The hemolytic uremic syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia and renal dysfunction. The typical form of HUS is generally associated with infections by Gram-negative Shiga toxin (Stx)-producing Escherichia coli (STEC). Endothelial dysfunction induced by Stx is central, but bacterial lipopolysaccharide (LPS) and neutrophils (PMN) contribute to the pathophysiology. Although renal failure is characteristic of this syndrome, neurological complications occur in severe cases and is usually associated with death. Impaired blood-brain barrier (BBB) is associated with damage to cerebral endothelial cells (ECs) that comprise the BBB. Astrocytes (ASTs) are inflammatory cells in the brain and determine the BBB function. ASTs are in close proximity to ECs, hence the study of the effects of Stx1 and LPS on ASTs, and the influence of their response on ECs is essential. We have previously demonstrated that Stx1 and LPS induced activation of rat ASTs and the release of inflammatory factors such as TNF-α, nitric oxide and chemokines. Here, we demonstrate that rat ASTs-derived factors alter permeability of ECs with brain properties (HUVECd); suggesting that functional properties of BBB could also be affected. Additionally, these factors activate HUVECd and render them into a proagregant state promoting PMN and platelets adhesion. Moreover, these effects were dependent on ASTs secreted-TNF-α. Stx1 and LPS-induced ASTs response could influence brain ECs integrity and BBB function once Stx and factors associated to the STEC infection reach the brain parenchyma and therefore contribute to the development of the neuropathology observed in HUS

    El conflicto entre cristianos y musulmanes en las relaciones de sucesos : la liberaciĂłn de Buda

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    Este trabajo propone el anĂĄlisis de una selecciĂłn de textos escritos en romance sobre la derrota turca y la toma de la ciudad de Buda en 1686, que denuncian la exultante acogida popular de la noticia de las gestas cristianas en Centroeuropa, la percepciĂłn del eterno conflicto entre Oriente y Occidente y la proyecciĂłn del imaginario colectivo del siglo xvii acerca de la lucha contra los infieles.This paper offers the analysis of a selection of texts, written in Romance languages, about the Turkish defeat and the conquest of the city of Buda in 1686, which provide evidence of the popular exultation at the news of the Christian achievements in Central Europe, the perception of the eternal conflict between East and West, and the projection of the seventeenth-century collective imagination regarding the struggle against the infidel

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

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    [This corrects the article DOI: 10.1186/s13054-016-1208-6.]

    Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

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    This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

    Actas de las V Jornadas ScienCity 2022. Fomento de la Cultura CientĂ­fica, TecnolĂłgica y de InnovaciĂłn en Ciudades Inteligentes

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    ScienCity es una actividad que viene siendo continuada desde 2018 con el objetivo de dar a conocer los conocimientos y tecnologĂ­as emergentes siendo investigados en las universidades, informar de experiencias, servicios e iniciativas puestas ya en marcha por instituciones y empresas, llegar hasta decisores polĂ­ticos que podrĂ­an crear sinergias, incentivar la creaciĂłn de ideas y posibilidades de desarrollo conjuntas, implicar y provocar la participaciĂłn ciudadana, asĂ­ como gestar una red internacional multidisciplinar de investigadores que garantice la continuaciĂłn de futuras ediciones. En 2022 se recibieron un total de 48 trabajos repartidos en 25 ponencias y 24 pĂłsteres pertenecientes a 98 autores de 14 instituciones distintas de España, Portugal, Polonia y PaĂ­ses Bajos.FundaciĂłn Española para la Ciencia y la TecnologĂ­a-Ministerio de Ciencia, InnovaciĂłn y Universidades; ConsejerĂ­a de la Presidencia, AdministraciĂłn PĂșblica e Interior de la Junta de AndalucĂ­a; Estrategia de PolĂ­tica de InvestigaciĂłn y Transferencia de la Universidad de Huelva; CĂĄtedra de InnovaciĂłn Social de Aguas de Huelva; CĂĄtedra de la Provincia; Grupo de investigaciĂłn TEP-192 de Control y RobĂłtica; Centro de InvestigaciĂłn en TecnologĂ­a, EnergĂ­a y Sostenibilidad (CITES
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