From embedded nanoislands to thin films: Topographic and optical properties of europium oxide on MgO(001) films

Combining scanning tunnelingmicroscopy and cathodoluminescence spectroscopy, we have explored different routes to produce luminescentMgOEu films on aMo(001) support. Codeposition of Eu and Mg in an O₂ ambience turned out to be unsuitable to prepare crystalline mixed oxides with distinct emission properties because of the large mismatch between the Eu and the Mg ion radius. In contrast, highly luminescent samples were obtained after annealing MgO-supported Eu particles in oxygen. The optically active species were identified as nanosized Eu₂O₃ islands embedded in the first MgO layer, while single Eu ions inside the host lattice are of minor importance. The MgOEu adsorption system exhibits a rich photon spectrum that comprises five emission bands in the wavelength region between 565 and 725 nm. They are assigned to electron transitions from the ⁵D0 excited to the ⁷FJ ground states of Eu³⁺, with the J quantum number running from 0 to 4. From the relative intensities of certain J transitions, we conclude that the respective Eu³⁺ ions occupy sites without inversion symmetry, a condition that is best fulfilled by Eu species at the perimeter of the Eu₂O₃ nanoislands.With increasing exposure, a europium-oxide film develops on top of the MgO surface, whose weak spectral signature is compatible with Eu³⁺ ions in more centrosymmetric surroundings. Our work demonstrates that relevant properties of Eu-based phosphors, being typically prepared in the form of powder samples, can be generated in thin-film systems as well, the latter being accessible to a range of surface-science techniques due to their finite conductivity

Autocatalytic growth of ZnO nanorods from flat Au(111)-supported ZnO films

Physical vapour deposition of ZnO on an Au(111) support has been investigated as a function of the oxygen chemical potential by means of scanning tunnelling microscopy and luminescence spectroscopy. Whereas a layer-by-layer growth of ZnO is revealed in oxygen excess, formation of oxide nanorods with large height-to-diameter ratio prevails at lower oxygen chemical potentials. We ascribe the formation of 3D nanostructures in the latter case to traces of Au atoms on the surface that promote trapping and dissociation of the incoming oxygen molecules. The Au residuals, acting as catalyst for the oxide formation, are indeed found on top of the ZnO nanorods

Higher resources decrease fluctuating selection during host-parasite coevolution

This is the final version of the article. Available from the publisher via the DOI in this record.We still know very little about how the environment influences coevolutionary dynamics. Here, we investigated both theoretically and empirically how nutrient availability affects the relative extent of escalation of resistance and infectivity (arms race dynamic; ARD) and fluctuating selection (fluctuating selection dynamic; FSD) in experimentally coevolving populations of bacteria and viruses. By comparing interactions between clones of bacteria and viruses both within- and between-time points, we show that increasing nutrient availability resulted in coevolution shifting from FSD, with fluctuations in average infectivity and resistance ranges over time, to ARD. Our model shows that range fluctuations with lower nutrient availability can be explained both by elevated costs of resistance (a direct effect of nutrient availability), and reduced benefits of resistance when population sizes of hosts and parasites are lower (an indirect effect). Nutrient availability can therefore predictably and generally affect qualitative coevolutionary dynamics by both direct and indirect (mediated through ecological feedbacks) effects on costs of resistance.This work was funded by NERC (UK). ABu was supported by the Royal Society and ABe by a the Leverhulme Trust Early Career Fellowship

Seismic effects in archaeological sites: Archaeoseismological cataloguing and quantification

The analysis of the damage caused by seismic events in archaeological sites provides significant information about ancient and historic earthquakes that can improve seismic hazard analysis. In this paper a methodological analysis to quantify the deformation of structural damage recorded in archaeological sites is proposed. This methodology focuses on the establishment of the seismic/non-seismic origin of the observed damage and consists of three phases: (a) identification and inventory of damage; (b) quantification of deformation; and (c) incorporation of the results to seismic catalogues. The first phase is the inventory and mapping of the damage according with the classification of archaeological effects of earthquakes (EAEs). The second phase is to quantify the deformation of damage by setting different parameters such as the direction of maximum horizontal strain (ey). This analysis is performed at different levels: for each of the recorded EAEs, for all the records of a particular category of EAEs, and finally for the complete archaeological site including all the categories of EAEs. The homogeneity of the results (damage orientation) allows us to establish the seismic origin of deformations. This methodology has been developed in the Roman site of Baelo Claudia (Cádiz, Spain) and has been applied to different historical earthquakes in the Iberian Peninsula. To calibrate the method, analyses on oriented damage were carried out immediately after the recent instrumental earthquakes of Lorca 2011 (5.1 Mw, Spain) and Emilia Romagna 2012 (5.9 Mw; Italy).The analysis of the damage caused by seismic events in archaeological sites provides significant information about ancient and historic earthquakes that can improve seismic hazard analysis. In this paper a methodological analysis to quantify the deformation of structural damage recorded in archaeological sites is proposed. This methodology focuses on the establishment of the seismic / non-seismic origin of the observed damage and consists of three phases: (a) identification and inventory of damage; (b) quantification of deformation; and (c) incorporation of the results to seismic catalogues. The first phase is the inventory and mapping of the damage according with the classification of archaeological effects of earthquakes (EAEs). The second phase is to quantify the deformation of damage by setting different parameters such as the direction of maximum horizontal strain (ey). This analysis is performed at different levels: for each of the recorded EAEs, for all the records of a particular category of EAEs, and finally for the complete archaeological site including all the categories of EAEs. The homogeneity of the results (damage orientation) allows us to establish the seismic origin of deformations. This methodology has been developed in the Roman site of Baelo Claudia (Cádiz, Spain) and has been applied to different historical earthquakes in the Iberian Peninsula. To calibrate the method, analyses on oriented damage were carried out immediately after the recent instrumental earthquakes of Lorca 2011 (5.1 Mw, Spain) and Emilia Romagna 2012 (5.9 Mw; Italy).Este trabajo ha sido financiado por los proyectos CGL2015-67169-P (QTECTSPAIN, USAL) y CATESI-07 (IGME). Es una contribución al INQUA TERPRO Project 1299 y a los grupos de trabajo QTECT-AEQUA y GQMAEQU

Evolution of the electronic structure of CaO thin films following Mo interdiffusion at high temperature

The electronic structure of CaO films of 10–60 monolayer thickness grown on Mo(001) has been investigated with synchrotron-mediated x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). Upon annealing or reducing the thickness of the film, a rigid shift of the CaO bands to lower energy is revealed. This evolution is explained with a temperature-induced diffusion of Mo ions from the metal substrate to the oxide and their accumulation in the interface region of the film. The Mo substitutes divalent Ca species in the rocksalt lattice and is able to release electrons to the system. The subsequent changes in the Mo oxidation state have been followed with high-resolution XPS measurements. While near-interface Mo transfers extra electrons back to the substrate, generating an interface dipole that gives rise to the observed band shift, near-surface species are able to exchange electrons with adsorbates bound to the oxide surface. For example, exposure of O2 results in the formation of superoxo species on the oxide surface, as revealed from STM measurements. Mo interdiffusion is therefore responsible for the pronounced donor character of the initially inert oxide, and largely modifies its adsorption and reactivity behavior

Osteomielitis y tumor de Ewing: aspectos clínicos y radiográficos comunes

La osteomielitis aguda y el tumor de Ewing, dos entidades de naturaleza bien distinta, pueden mostrar semejanzas clínicas y radiográficas. Presentamos un caso de tumor de Ewing clásico y dos de osteomielitis que plantearon sendas dudas diagnósticas. Concluimos insistiendo en la importancia de un diagnóstico diferencial definitivo precoz mediante biopsia y cultivo en estas circunstancias.Acute osteomyelitis and Ewing's sarcoma are diseases of quite different natur e which may show similar clinical and radiographic characteristics. The author s present a case of classic Ewing's sarcoma ant two case s of osteomyelitis that suposed diagnosti c doubts in each case . They conclude emphasizing on the importanc e of an early, definitive differential diagnosis in thes e circunstance s by means of a biopsy and bacteriologic culture

Facies control on seismites in an alluvial–aeolian system: the Pliocene dunefield of the Teruel half-graben basin (eastern Spain)

The recognition of seismically induced soft-sediment deformation structures (SSDS) in sedimentary successions characterized by different facies, and hence by different rheology, is challenging. This is the case for high porosity and high permeability aeolian facies interbedded with muddy wet interdune deposits and alluvial conglomerates and sandstones. Several types of SSDS have been studied in two exposures of the Upper Pliocene (2.9–2.6 Ma) sediments of a fault-bounded intracontinental aeolian dune field in the Teruel Basin (Iberian Chain, eastern Spain). Among SSDS, load and fluid-escape structures, apart from several animal tracks, have been recognized. Those structures show an irregular distribution through the studied stratigraphic sections, being scarce in homogenous aeolian sands and frequent in water-related facies. A detailed study of the distribution and geometry of SSDS and their relationships with respect to the stratigraphic architecture and facies has allowed a critical discrimination of trigger mechanisms, i.e. biological or physical overloading vs. earthquakes. The seismically induced structures are concentrated into seven deformed beds, showing an uneven lateral distribution and geometry closely controlled by the hosting sedimentary facies and their rheology. These seismites resulted from liquefaction during moderate earthquakes (estimated magnitude from 5.0 to 6.8). The most probable seismogenic source was the Sierra del Pobo normal fault zone, located 2 km to the East. Results show how an appropriate recognition of sedimentary facies is crucial to understand the lateral variability of seismites in sedimentary environments characterized by sharp facies changes

La toma de muestras intraoperatorias con hisopo para el diagnóstico precoz de una infección de prótesis total de cadera es una práctica ineficaz

El diagnóstico de infección articular periprotésica es motivo de reuniones y consensos internacionales. Sin embargo, no hay consenso sobre cuál es la prueba más adecuada para identificar de manera profiláctica el o los microorganismos responsables. En este trabajo se realiza un estudio retrospectivo de 1.022 pacientes a los que se les implantaron 1.045 prótesis totales de cadera entre los años 2009-2013, ambos inclusive. Se analizan los resultados del cultivo de muestras tomadas intraoperatoriamente identificándose los microorganismos aislados y su correlación con la clínica de infección. Se calcularon la sensibilidad, especificidad, valores predictivos positivos y negativos de la prueba. Se identificaron los pacientes con complicaciones infecciosas, la clasificación de los mismos según criterios de Tsukayama y el tratamiento realizado. Concluimos que la toma rutinaria de muestras intraoperatorias en la artroplastia primaria de cadera para intentar adelantar el diagnóstico de una infección periprotésica es una práctica ineficaz e ineficiente y, por ello, hay que abandonarla.There are many international meetings and consensus about the diagnosis of periprosthetic joint infection. However, there aren´t consensus about the most appropriate test to identify the prophylactically microorganisms responsible of infection. This paper is a retrospective study of 1.022 patients with 1.045 total hip replacements between 2009-2013. We analyzed the results of intraoperative culture samples, identified the microorganisms and the patients with clinical infection. We calculated the sensitivity, specificity, positive and negative predictive values of the test. The patients with infectious were identified and classified according to criteria Tsukayama and treatment performed. We conclude that intraoperative culture samples in primary hip arthroplasty to try to advance the diagnosis of periprosthetic infection are an ineffective and inefficient practice and we have to stop doing it

La prótesis Bicontact resultados a 11 años de seguimiento

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