Synthesis of 3D porous ceramic scaffolds obtained by the sol-gel method with surface morphology modified by hollow spheres for bone tissue engineering applications

In the present work, we modified the surface morphology of 3D porous ceramic scaffolds by incorporating strontium phosphate (SrP) hollow nano-/microspheres with potential application as delivery system for the local release of therapeutic substances. SrP hollow spheres were synthesized by a template-free hydrothermal method. The influence of the reaction temperature, time and concentration of reactants on precipitates' morphology and size were investigated. To obtain a larger number of open hollow spheres, a new methodology was developed consisting of applying a second hydrothermal treatment to spheres by heating them at 120 °C for 24 h. The X-ray diffraction (XRD) analysis indicated that spheres consisted of a main magnesium-substituted strontium phosphate phase ((Sr3(PO4)2). The scanning electron microscopy (SEM) micrographs confirmed that spheres had hollow interiors (∼350 nm size) and an average diameter of 850 nm. Spheres had a specific surface area of 30.5 m2/g, a mesoporous shell with an average pore size of 3.8 nm, and a pore volume of 0.14 cm/g. These characteristics make them promising candidates for drug, cell and protein delivery. For the attachment of spheres to scaffolds’ surface, ceramic structures were immersed in an ethanol solution containing 0.1 g of hollow spheres and kept at 37 °C for 4 h. The scaffolds with incorporated spheres were bioactive after being immersed in simulated body fluid (SBF) for 7 days and spheres were still adhered to their surface after 14 daysThis work is part of the project PID2020-116693RB-C21 funded by MCIN/AEI/10.13039/501100011033 Spain. Grant CIAICO/2021/157 funded by Generalitat Valenciana Spain

Decay of Complex-time Determinantal and Pfaffian\ Correlation Functionals in Lattices

We supplement the determinantal and Pfaffian bounds of Sims and Warzel (Commun Math Phys 347:903--931, 2016) for many-body localization of quasi-free fermions, by considering the high dimensional case and complex-time correlations. Our proof uses the analyticity of correlation functions via the Hadamard three-line theorem. We show that the dynamical localization for the one-particle system yields the dynamical localization for the many-point fermionic correlation functions, with respect to the Hausdorff distance in the determinantal case. In Sims and Warzel (2016), a stronger notion of decay for many-particle configurations was used but only at dimension one and for real times. Considering determinantal and Pfaffian correlation functionals for complex times is important in the study of weakly interacting fermions.FAPESP, the CNPq, the Basque Government through the grant IT641-1

Contribución al conocimiento de los depósitos caoliníferos de Pontevedra

[Resumo] Encétase o traballo cunha escolma dos depósitos caoliníferos que poidan ter interés dende o punto de vista económico ou polas características peculiares da súa xénesis. Destes depósitos elixidos fíxose, en base a unha labor de campo, o seu estudo xeolóxico e a recolleita de mostras que foron identificadas mineralóxicamente coas técnicas instrumentais usuais, describindo seguidamente os resultados. Os materiais que ofreceron un maior interés, estudáronse con vistas a súa aplicación na industria dos refractarios, feito que ven xustificado por existir naquela comarca algunhas fábricas en actividade, unha delas xa centenaria. No derradeiro capítulo, fáise unha valoración dos resultados obtidos e conclúese que os depósitos caoliníferos da provincia de Pontevedra, veñen da meteorización de rochas graníticas ou metamórficas de carácter ácedo, ou son sedimentarios o que vai influír nas súas propiedades técnicas. Dende o punto de vista mineralóxico, tanto uns como outros, compóñense de caolinita, halloisita, seixo, micas e feldespato potásico, presentando pequenas diferencias na súa cristalinidade e no contido de minerais minoritarios. Polo que respecta ao aspecto técnico, encontráronse depósitos aproveitables, uns para a produción de caolín lavado e outros como arxilas refractarias tipo "fire-clay", ou plásticas, tipo "ball-clay", axeitadas para a fabricación de materiais refractarios aluminosos, chamotas e gres, aínda que é necesario profundar máis o aspecto técnico, o que ata hoxe non se fixo

Biomechanical effects of a new macrogeometry design of dental implants: an in vitro experimental analysis

The purpose of the present study was to measure and compare the insertion torque, removal torque, and the implant stability quotient by resonance frequency analysis in different polyurethane block densities of two implant macrogeometries. Four different polyurethane synthetic bone blocks were used with three cortical thickness: Bone 1 with a cortical thickness of 1 mm, Bone 2 with a cortical thickness of 2 mm, Bone 3 with a cortical thickness of 3 mm, and Bone 4, which was totally cortical. Four groups were created in accordance with the implant macrogeometry (n = 10 per group) and surface treatment: G1—regular implant design without surface treatment; G2—regular implant design with surface treatment; G3—new implant design without surface treatment; G4—new implant design with surface treatment. All implants used were 4 mm in diameter and 10 mm in length and manufactured in commercially pure titanium (grade IV) by Implacil De Bortoli (São Paulo, Brazil). The implants were installed using a computed torque machine, and following installation of the implant, the stability quotient (implant stability quotient, ISQ) values were measured in two directions using Osstell devices. The data were analyzed by considering the 5% level of significance. All implant groups showed similar mean ISQ values without statistical differences (p > 0.05), for the same synthetic bone block: for Bone 1, the value was 57.7 ± 3.0; for Bone 2, it was 58.6 ± 2.2; for Bone 3, it was 60.6 ± 2.3; and for Bone 4, it was 68.5 ± 2.8. However, the insertion torque showed similar higher values for the regular macrogeometry (G1 and G2 groups) in comparison with the new implant macrogeometry (G3 and G4 groups). The analysis of the results found that primary stability does not simply depend on the insertion torque but also on the bone quality. In comparison with the regular implant macrogeometry, the new implant macrogeometry decreased the insertion torque without affecting the implant stability quotient values

Intervención educativa a través de las habilidades circenses en el ámbito extraescolar

Las actividades circenses se pueden llevar a cabo dentro del ámbito escolar como actividad extraescolar, siendo muy enriquecedoras para el alumnado del tercer ciclo de primaria, concibiéndolas como un arte en el que los alumnos pueden demostrar individualmente su creatividad. En la adquisición de un aprendizaje, sobre todo de habilidades y destrezas circenses, los temas emocionales, motivacionales, relaciones, motrices y artísticos tienen una gran importancia.Grado en Educación Primari

Quaternary phase equilibrium diagrams. Representation and interpretation methods

[ES] Se describen los métodos de representación utilizados en el estudio de los diagramas de equilibrio de fases cuaternarios así como su interpretación. Se exponen los inconvenientes del método tradicional, o de intersección, para la interpretación y utilización de dichos diagramas. Se describe detalladamente un método alternativo, denominado método de proyección, utilizado por los autores para el estudio experimental de los diagramas de equilibrio cuaternarios, indicando simultáneamente las ventajas de dicho método sobre el de intersección. Finalmente, se presentan los resultados obtenidos, al aplicar el método de proyección, al estudio de los sistemas: MgO-CaO-SiO2-ZrO2, y Al2O3-SiO2-TiO2-Fe2O3.[EN] Se describen los métodos de representación utilizados en el estudio de los diagramas de equilibrio de fases cuaternarios así como su interpretación. Se exponen los inconvenientes del método tradicional, o de intersección, para la interpretación y utilización de dichos diagramas. Se describe detalladamente un método alternativo, denominado método de proyección, utilizado por los autores para el estudio experimental de los diagramas de equilibrio cuaternarios, indicando simultáneamente las ventajas de dicho método sobre el de intersección. Finalmente, se presentan los resultados obtenidos, al aplicar el método de proyección, al estudio de los sistemas: MgO-CaO-SiO2-ZrO2, y Al2O3-SiO2-TiO2-Fe2O3.Los autores desean agradecer el soporte financiero de CICYT España bajo el proyecto MAT-2003-08331-C02-01 y a la Comunidad Autónoma de Madrid CAM-07N/0038/2001MAT- 2000-0941. B. Vázquez desea agradecer a la Universidad Autónoma de Nuevo León-México la concesión de la beca PROMEP.Peer reviewe

Carbon in heartwood, sapwood and bark along stem profile in three Mediterranean Pinus species

Context Understanding biological processes in forests is necessary to orientate ecosystem management towards potential C sequestration. To achieve this, information is required about changes in forest biomass C pools, including the stem components (bark, sapwood and heartwood). Aims This study aimed to determine whether there are differences in C concentration in axial and radial directions within stem biomass in Pinus nigra, Pinus pinaster and Pinus sylvestris. Methods Wood samples from a permanent plantation in northern Spain were examined for C concentration and wood bulk density. Results The results showed that C concentration was higher in heartwood than in sapwood in the three species. Pinus spp. sapwood C concentration increased along the stem, while the C concentration in heartwood tissue showed the opposite behavior. In bark, Pinus pinaster showed a decreasing trend, in contrast to Pinus nigra and Pinus sylvestris, where higher values were found at the base and top of the stem. Finally, wood bulk density decreased in heartwood, sapwood and bark areas when stem height increased. Estimating C content taking into account different anatomical parts and heights is important in considering the specificity of the different parts because of their potential commercial or ecological use in forest ecosystems.Instituto Universitario de Gestión Forestal Sostenibl

Accuracy of Classical Conductivity Theory at Atomic Scales for Free Fermions in Disordered Media

The growing need for smaller electronic components has recently sparked the interest in the breakdown of the classical conductivity theory near the atomic scale, at which quantum effects should dominate. In 2012, experimental measurements of electric resistance of nanowires in Si doped with phosphorus atoms demonstrate that quantum effects on charge transport almost disappear for nanowires of lengths larger than a few nanometers, even at very low temperature (4.2K). We mathematically prove, for non-interacting lattice fermions with disorder, that quantum uncertainty of microscopic electric current density around their (classical) macroscopic values is suppressed, exponentially fast with respect to the volume of the region of the lattice where an external electric field is applied. This is in accordance with the above experimental observation. Disorder is modeled by a random external potential along with random, complex-valued, hopping amplitudes. The celebrated tight-binding Anderson model is one particular example of the general case considered here. Our mathematical analysis is based on Combes-Thomas estimates, the Akcoglu-Krengel ergodic theorem, and the large deviation formalism, in particular the Gärtner-Ellis theorem.This research is supported by CNPq (308337/2017-4), FAPESP (2016/02503-8, 2017/22340-9), as well as by the Basque Government through the grant IT641-13 and the BERC 2018-2022 program, and by the Spanish Ministry of Economy and Competitiveness MINECO: BCAM Severo Ochoa accreditation SEV-2017-0718, MTM2017-82160-C2-2-P

Bioeutectic® ceramics for biomedical application obtained by laser floating zone method. In vivo evaluation

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license.In this study, the Bioeutectic® blocks were inserted into the critical size defects of eight rabbits, using both tibiae, and the physical and chemical nature of the remodeled interface between the Bioeutectic® implants and the surrounding bone were performed at four and 15 months. The results showed a new fully mineralized bone growing in direct contact with the implants. The ionic exchange, taking place at the implant interface with the body fluids was essential in the process of the implant integration through a dissolution-precipitation-transformation mechanism. The study found the interface biologically and chemically active over the 15 months implantation period. The osteoblastic cells migrated towards the interface and colonized the surface at the contact areas with the bone. The new developed apatite structure of porous morphology mimics natural bone. © 2014 by the authors.The authors wish to acknowledge funding from the European Community at the 7th Framework Program EU No. 314630-UV Marking and Generalitat Valenciana (GVA) within the Project ACOMP/2009/173.Peer Reviewe

Potential climatic influence on maximum stand carrying capacity for 15 Mediterranean coniferous and broadleaf species

Climate change projections for the Mediterranean basin predict a continuous increase in extreme drought and heat episodes, which will affect forest dynamics, structure and composition. Understanding how climate influences the maximum size-density relationship (MSDR) is therefore critical to designing adaptive silvicultural guidelines based on the potential stand carrying capacity of tree species. With this aim, data from the Third Spanish National Forest Inventory (3NFI) and WorldClim databases were used to analyze climate-related variations of the maximum stand carrying capacity for 15 species from the Pinus, Fagus and Quercus genera. First, basic MSDR were fitted using linear quantile regression and observed size-density data from monospecific 3NFI plots. Reference values for maximum stocking, expressed in terms of the Maximum Stand Density Index (SDImax), were estimated by species. Then, climate-dependent MSDR models including 35 annual and seasonal climatic variables were fitted. The best climate-dependent models, based on the Akaike Information Criteria (AIC) index, were used to determine the climatic drivers affecting MSDR, to analyze general and species-specific patterns and to quantify the impact of climate on maximum stand carrying capacity. The results showed that all the selected climate-dependent models improved the goodness of fit over the basic models. Among the climatic variables, spring and summer maximum temperatures were found to be key drivers affecting MSDR for the species studied. A common trend was also found across species, linking warmer and drier conditions to smaller SDImax values. Based on projected climate scenarios, this suggests potential reductions in maximum stocking for these species. In this study, a new index was proposed, the Q index, for evaluating the impact of climate on maximum stand carrying capacity. Our findings highlight the importance of using specific climatic variables to better characterize how they affect MSDR. The models presented in this study will allow us to better explain interactions between climate and MSDR while also providing more precise estimates concerning maximum stocking for different Mediterranean coniferous and broadleaf tree species.Industrial PhD project [grant DI-15-07722]Torres Quevedo programme [grant PTQ-12-05409