Synthesis, characterization, bioactivity and biocompatibility of nanostructured materials based on the wollastonite-poly(ethylmethacrylate-co-vinylpyrrolidone) system

Composite materials are very promising biomaterials for hard tissue augmentation. The approach assayed in this work involves the manufacturing of a composite made of a bioactive ceramic, natural wollastonite (W) and a nanostructured copolymer of ethylmethacrylate (EMA) and vinylpyrrolidone (VP) to yield a bioresorbable and biocompatible VP–EMA copolymer. A bulk polymerization was induced thermally at 508C, using 1 wt % azobis(isobutyronitrile) (AIBN) as free-radical initiator. Structural characterization, compressive strength, flexural strength (FS), degradation, bioactivity, and biocompatibility were evaluated in specimens with a 60/40 VP/EMA ratio and ceramic content in the range 0–60%. A good integration between phases was achieved. Greater compression and FS, in comparison with the pure copolymer specimens was obtained only when the ceramic load got up to 60% of the total weight. The soaking in NaCl solution resulted in the initial swelling of the specimens tested. The maximum swelling was reached after 2–3 h of immersion and it was significantly greater for lower ceramic loads. This result makes the polymer component the main responsible for the interactions with the media. After soaking in SBF, microdomains segregation can be observed in the polymer component that can be related with a dramatic difference in the reactivity of both monomers in free radical polymerization, whereas the formation of an apatite-like layer on the W surfaces can be observed. Biocompatibility in vitro studies showed the absence of cytotoxicity of all formulations. The cells were able to adhere on the polystyrene negative control and on specimens containing 60 wt % wollastonite forming a monolayer and showing a normal morphology. However, a low cellular growth was observed. 2008 Wiley Periodicals, Inc. J Biomed Mater Res 88A: 53–64, 2009Peer reviewe

Spreading fronts of wetting liquid droplets: microscopic simulations and universal fluctuations

We have used kinetic Monte Carlo (kMC) simulations of a lattice gas to study front fluctuations in the spreading of a non-volatile liquid droplet onto a solid substrate. Our results are consistent with a diffusive growth law for the radius of the precursor layer, $R \sim t^{\delta}$, with $\delta \approx 1/2$ in all the conditions considered for temperature and substrate wettability, in good agreement with previous studies. The fluctuations of the front exhibit kinetic roughening properties with exponent values which depend on temperature $T$, but become $T$-independent for sufficiently high $T$. Moreover, strong evidences of intrinsic anomalous scaling have been found, characterized by different values of the roughness exponent at short and large length scales. Although such a behavior differs from the scaling properties of the one-dimensional Kardar-Parisi-Zhang (KPZ) universality class, the front covariance and the probability distribution function of front fluctuations found in our kMC simulations do display KPZ behavior, agreeing with simulations of a continuum height equation proposed in this context. However, this equation does not feature intrinsic anomalous scaling, at variance with the discrete model.Comment: 15 pages and 14 figures. To be published in PR

Temporalidad, eficiencia técnica y productividad: El sector hotelero en Canarias

This research focuses on analyzing the effect of high employment temporality on technical efficiency and productivity. Previous literature points out a set of benefits and drawbacks related to fixed-term contracts. To ascertain the influence of temporality on efficiency, the critical case of the hotel sector in the Canary Islands is studied where the temporary employment rate (40%). So this paper explores the effect of temporary employment on technical efficiency in the hotel sector of the Canary Islands (a Spanish region). The magnitude of this case study can be clearly checked, given that the Canary Islands is the most popular region in the European Union visited by residents. A production stochastic frontier is estimated by distinguishing between two types of employment: permanent and temporary. Results suggest that high levels of temporality tend to reduce technical efficiency and productivity. A high conversion rate from temporary to permanent jobs seems to increase efficiency. The contribution of this paper is threefold: (i) filling the gap in the literature on the influence of temporary employment on technical efficiency, evaluating its effect for a case study where job temporality is dramatically high, (ii) partial factor productivities for permanent and fixed-term workers are estimated, and (iii) exploring the influence of less studied variables like the level of conversion from fixed-term to permanent employment on efficiency. The findings can be relevant for human resources management for firms where temporary rates are high. Human resource management should consider the type of labor contracts used, as well as the perspectives of conversion into permanent ones for their temporary workers, given their potential influence in technical efficiency, labour productivity, and firm performance.Esta investigación se centra en analizar el efecto de la alta temporalidad del empleo sobre la eficiencia técnica y la productividad. La literatura previa señala un conjunto de beneficios e inconvenientes relacionados con los contratos temporales. Para conocer la influencia de la temporalidad sobre la eficiencia, se estudia el caso crítico del sector hotelero en Canarias donde la tasa de temporalidad es del 40%. Así, este trabajo explora el efecto de la temporalidad sobre la eficiencia técnica en el sector hotelero de Canarias (región española). La magnitud de este caso de estudio puede comprobarse claramente, dado que las Islas Canarias es la región de la Unión Europea más visitada por los residentes. Se estima una frontera estocástica de producción distinguiendo entre dos tipos de empleo: permanente y temporal. Los resultados sugieren que altos niveles de temporalidad tienden a reducir la eficiencia técnica y la productividad. Una alta tasa de conversión de empleos temporales a permanentes parece aumentar la eficiencia. La contribución de este trabajo es triple: (i) llenar el vacío en la literatura sobre la influencia del empleo temporal en la eficiencia técnica, evaluando su efecto para un caso de estudio en el que la temporalidad del empleo es dramáticamente alta, (ii) se estiman las productividades parciales de los factores para los trabajadores permanentes y de duración determinada, y (iii) se explora la influencia de variables menos estudiadas como el nivel de conversión de empleo de duración determinada a permanente en la eficiencia. Las conclusiones pueden ser relevantes para la gestión de los recursos humanos de las empresas en las que las tasas de temporalidad son elevadas. La gestión de recursos humanos debería considerar el tipo de contratos laborales utilizados, así como las perspectivas de conversión en indefinidos de sus trabajadores temporales, dada su potencial influencia en la eficiencia técnica, la productividad laboral y el rendimiento de la empresa

Optical Trapping of Single Nanostructures in a Weakly Focused Beam. Application to Magnetic Nanoparticles

"This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see [insert ACS Articles on Request author-directed link to Published Work, see https://pubs.acs.org/doi/10.1021/acs.jpcc.8b04676."[EN] Optical trapping of individual particles is believed to be only effective under highly focused beams because these conditions strengthen the gradient forces. This is especially critical in the beam propagating direction, where the scattering and absorption forces must be counterbalanced. Here, we demonstrate that optical trapping of nanostructures is also possible in a weakly focused beam. We study the theoretical conditions for effective three-dimensional optical confinement and verify them experimentally on iron-oxide-based nanoparticles with and without a silica coating, for which scattering, absorption, and gradient forces exist. This chemical approach to their all-optical control is, in turn, convenient for making magnetic nanostructures biocompatible. Weakly focused beams reduce the irradiance in the focal region and therefore the photon damage to the samples, which is further important to delay quantum dot quenching in the trap or to prevent artifacts in the study of biomolecular motor dynamics.We are grateful to Dr. Maria Acebron and Dr. Beatriz H. Juarez for their support in the silica encapsulation of the nano particles. This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Grant MAT2015-71806-R). IMDEA Nanociencia acknowledges support from the "Severo Ochoa" Programme for Centers of Excellence in R&D (MINECO, Grant SEV-2016-0686). H.R.-R. is supported by an FPI-UAM fellowship.Rodríguez-Rodríguez, H.; De Lorenzo, S.; De La Cueva, L.; Salas, G.; Arias-Gonzalez, JR. (2018). Optical Trapping of Single Nanostructures in a Weakly Focused Beam. Application to Magnetic Nanoparticles. The Journal of Physical Chemistry C. 122(31):18094-18101. https://doi.org/10.1021/acs.jpcc.8b04676S18094181011223

Spreading fronts of wetting liquid droplets: microscopic simulations and universal fluctuations

We have used kinetic Monte Carlo (kMC) simulations of a lattice gas to study front fluctuations in the spreading of a nonvolatile liquid droplet onto a solid substrate. Our results are consistent with a diffusive growth law for the radius of the precursor layer, R ∼ t δ , with δ ≈ 1 / 2 in all the conditions considered for temperature and substrate wettability, in good agreement with previous studies. The fluctuations of the front exhibit kinetic roughening properties with exponent values which depend on temperature T , but become T independent for sufficiently high T . Moreover, strong evidence of intrinsic anomalous scaling has been found, characterized by different values of the roughness exponent at short and large length scales. Although such a behavior differs from the scaling properties of the one-dimensional Kardar-Parisi-Zhang (KPZ) universality class, the front covariance and the probability distribution function of front fluctuations found in our kMC simulations do display KPZ behavior, agreeing with simulations of a continuum height equation proposed in this context. However, this equation does not feature intrinsic anomalous scaling, at variance with the discrete model.This work was partially supported by Ministerio de Economía, Industria y Competitividad (MINECO, Spain), Agencia Estatal de Investigación (AEI, Spain), and Fondo Europeo de Desarrollo Regional (FEDER, EU) through Grants No. PID2020-112936GB-I00 and No. PGC2018-094763-BI00, by the Junta de Extremadura (Spain) and Fondo Europeo de Desarrollo Regional (FEDER, EU) through Grants No. GRU18079 and No. IB20079, and by Comunidad de Madrid (Spain) under the Multiannual Agreement with UC3M in the line of Excellence of University Professors (EPUC3M23), in the context of the 5th Regional Programme of Research and Technological Innovation (PRICIT). J.M.M. was supported by Programa Propio de Investigación a la Investigación de la Universidad de Extremadura through Scolarship No. 1362. P.R.-L. was supported by "AYUDA PUENTE 2021, URJC." Our kMC simulations have been performed in the computing facilities of the Instituto de Computación Científica Avanzada de Extremadura (ICCAEx)

Intra-varietal diversity for agronomic traits in 'Garnacha Blanca'

'Garnacha Blanca' is a somatic variant derived from 'Garnacha Tinta', an old variety with large genetic and phenotypic variability. In this work we have studied for two years the phenotypic variation existing in 'Garnacha Blanca' for yield and quality related traits in accessions from 14 sampling locations of ancient vineyards in the Ebro Valley, Spain. The results showed high variability among the accessions in many of the traits studied in 'Garnacha Blanca'. Different accessions could be distinguished both years using several traits, including two important traits in terms of quality and yield: bunch compactness and yield per plant. A large environment effect, intrinsic to the 'Garnacha' group, enhances phenotypic variation among years, what requires increasing the number of bunches and years for clonal characterization in this variety. The dimensions of the berry showed the least variability, while traits related to bunch architecture like bunch length were discriminant and also stable

Estudio de la biocompatibilidad in vitro de formulaciones acrílicas autocurables portadoras de bisfosfonatos de nueva síntesis

En este trabajo se presenta el estudio de la biocompatibilidad in vitro, empleando cultivos celulares de fibroblastos embrionarios humanos, de tres sistemas acrílicos de liberación controlada de bisfosfonatos (BFs). Estos sistemas, basados en metacrilato de metilo (MMA), metacrilato de vitamina E (MVE) y trietilenglicol dimetacrilato (TEGDMA), han sido diseñados para su aplicación en el tratamiento de enfermedades caracterizadas por una elevada resorción osteoclástica. En su preparación se ha empleado un BP comercializado (alendronato; ALN) y dos de nueva síntesis, pertenecientes a la segunda y tercera generaciones, el ácido 1-hidroxi-2-[4-aminofenil]etano-1,1-difosfónico (APBP) y el ácido 1-hidroxi-2-[3-indolil]etano-1,1-difosfónico (IBP), respectivamente. La citotoxicidad de MVE ha sido notablemente inferior a la medida para TEGDMA. La citotoxicidad de APBP e IBP se ha comparado con la de ALN, obteniéndose unos valores para la concentración IC50, de15,56, 9,86 y 6,25 mmol/l para APBP, ALN e IBP, respectivamente. Los niveles de citotoxicidad liberada han sido superiores para la formulación portadora de ALN, situándose a continuación los cementos cargados con IBP y APBP. Cuando los cultivos se han establecido sobre la superficie de las formulaciones, se han detectado unos niveles de proliferación celular y adhesión superiores para los sistemas de liberación de IBP y APBP, siendo además inferior en estos casos la mortalidad celular.This paper reports the in vitro biocompatibility study, using human embryonic fibroblast cultures, of three acrylic systems for controlled release of bisphosphonates (BFs). These systems, that are based on methyl methacrylate (MMA), vitamin E methacrylate (MVE) and triethyleneglycol dimethacrylate (TEGDMA), have been designed for its application in the treatment of pathologies characterized by a high osteoclastic resorption. A commercial BP (alendronate; ALN) and two novel BPs, belonging to the second and third generations, 1-hydroxy-2-[4-aminophenyl]ethane-1,1-diphosphonic acid (APBP) and 1-hydroxy-2-[3-indolyl]ethane-1,1-diphosphonic acid (IBP), respectively, have been used in their preparation. The cytotoxicity of MVE has been notably lower than that measured for TEGDMA. Cytotoxicity of APBP and IBP was evaluated along with that of ALN, and the following values of the IC50, concentration were obtained for APBP, ALN and IBP respectively: 15.56, 9.86 and 6.25 mmol/l. The cytotoxicity levels obtained from the extracts of the cured systems were higher for the formulation containing ALN, followed by the cements loaded with IBP and APBP. When the cultures were seeded directly on the formulations surface, higher levels of cellular proliferation and adhesion were obtained for the systems containing IBP and APBP, the cellular mortality being also inferior in these cases

Identification and evaluation of fungal strains with fucoidan degradation potential

Ten fungal strains isolated of Mexican semi-desert were screened for ability to hydrolyze fucoidan in order to search microorganism capable to produce sulfated fucans-degrading enzymes. Plate assay and liquid fermentation experiments were carried out using Laminaria japonica fucoidan as only carbon source, testing three nitrogen sources. Growth was observed only in Aspergillus niger PSH, Mucor sp., and Penicillum purpurogenum GH2 in fucoidan-urea medium. The activity of fucoidanases was determined by reduced sugars. Aspergillus niger PSH showed the highest activity titles. This research indicate that filamentous fungi, using specific medium, are sources enable to induce active metabolism that act toward this class of polysaccharide

Individual Differences in Music Reward Experiences

Music is one of the most pleasant human experiences, even though it has no direct biological advantage. However little is known about individual differences in how people experience reward in music-related activities. The goal of the present study was to describe the main facets of music experience that could explain the variance observed in how people experience reward associated with music. To this end we developed the Barcelona Music Reward Questionnaire (BMRQ), which was administrated to three large samples. Our results showed that the musical reward experience can be decomposed into five reliable factors: Musical Seeking, Emotion Evocation, Mood Regulation, Social Reward, and Sensory-Motor. These factors were correlated with socio-demographic factors and measures of general sensitivity to reward and hedonic experience. We propose that the five-factor structure of musical reward experience might be very relevant in the study of psychological and neural bases of emotion and pleasure associated to music

Search of Potential Vaccine Candidates against Trueperella pyogenes Infections through Proteomic and Bioinformatic Analysis

Trueperella pyogenes is an opportunistic pathogen, responsible for important infections in pigs and significant economic losses in swine production. To date, there are no available commercial vaccines to control diseases caused by this bacterium. In this work, we performed a comparative proteomic analysis of 15 T. pyogenes clinical isolates, by “shaving” live cells, followed by LC-MS/MS, aiming at the identification of the whole set of surface proteins (i.e., the “pan-surfome”) as a source of antigens to be tested in further studies as putative vaccine candidates, or used in diagnostic tools. A total of 140 surface proteins were detected, comprising 25 cell wall proteins, 10 secreted proteins, 23 lipoproteins and 82 membrane proteins. After describing the “pan-surfome”, the identified proteins were ranked in three different groups based on the following criteria: to be (i) surface-exposed, (ii) highly conserved and (iii) widely distributed among different isolates. Two cell wall proteins, three lipoproteins, four secreted and seven membrane proteins were identified in more than 70% of the studied strains, were highly expressed and highly conserved. These proteins are potential candidates, alone or in combination, to obtain effective vaccines against T. pyogenes or to be used in the diagnosis of this pathogen