Structure of Portland Cement Pastes Blended with Sonicated Silica Fume

[EN] Application of power ultrasound to enhance dispersion of commercial densified silica fume leads to increased compressive strengths and refinement of the pore structure in mortars, compared with those that are untreated. This was attributed to the enhanced pozzolanic reactivity achieved by particle dispersion through sonication, leading to higher consumption of portlandite during curing, and formation of a calcium silicate hydrate gel with a higher degree of cross-linking than is identified in specimens with densified silica fume. This suggests that with the use of sonicated silica fume, it is possible to reduce the required quantity of admixture in blended cements to achieve specified performance, with the additional advantage of the formation of a highly densified structure and refined pore network, contributing to potential improvements in durability.This study was sponsored by the Ministerio de Ciencia e Innovacion of Spain (Project SILISONIC BIA-2007-63252 and research scholarships BES-2008-002440 and EEBB-2011-43847), the European regional development fund (FEDER), and the Universitat Politecnica de Valencia (Spain). Participation of SAB and JLP was funded by the Australian Research Council (ARC), including partial funding through the Particulate Fluids Processing Centre, a Special Research Centre of the ARC. The authors thank Dr. John Gehman for support in conducting the NMR experiments at the Bio21 Institute, University of Melbourne, Australia.Rodriguez Martinez, ED.; Bernal, SA.; Provis, JL.; Paya Bernabeu, JJ.; Monzó Balbuena, JM.; Borrachero Rosado, MV. (2012). Structure of Portland Cement Pastes Blended with Sonicated Silica Fume. Journal of Materials in Civil Engineering. 24:1295-1304. https://doi.org/10.1061/(ASCE)MT.1943-5533.0000502S129513042

Physical mechanisms and parameters for models of microstructure evolution under irradiation in Fe alloys – Part I: Pure Fe

This paper is the first of three that overview the main mechanisms that drive the microstructure evolution in Fe alloys under irradiation. It focuses on pure α-Fe and compiles the parameters that describe quantitatively the mobility and stability of point-defects and especially their clusters, including possible reactions and criteria to decide when they should react. These parameters are the result of several years of calculations and application in microstructure evolution models. They are mainly collected from the literature and the parameter choice tries to reconcile different sets of values that, while being in general qualitatively similar, are often quantitatively not coincident. A few calculation results are presented here for the first time to support specific approximations concerning defect properties or features. Since calculations cannot cover all possible defect configurations, the definition of these parameters often requires educated guesses to fill knowledge gaps. These guesses are here listed and discussed whenever relevant. This is therefore a “hands-on” paper that: (i) collects in a single report most microstructure evolution parameters that are found in the literature for irradiated α-Fe, including a discussion of the most important mechanisms at play based on current knowledge; (ii) selects a ready-to-use set that can be employed in microstructure evolution models, such as those based on object kinetic Monte Carlo (OKMC) methods. This work also identifies parameters that are needed, but not known, hopefully prompting corresponding calculations in the future.This work has received funding from the Euratom research and training programme 2014-2018 under grant agreement No. 755039 (M4F project). This research also contributes to the Joint Programme on Nuclear Materials of the European Energy Research Alliance (EERA-JPNM)

An approach to a new supplementary cementing material: Arundo donax straw ash material

[EN] Arundo donax is a plant native to Asia and is considered an invader species in the Mediterranean region and many tropical zones in the world. These invader plants can be collected to produce a biomass, which can be converted to ash by combustion. The scope of the study is to assess the use of these ashes (Arundo donax straw ash [ADSA]) as supplementary cementing material due to their relatively high silica content. Electron microscopy studies on dried and calcined samples of different plant parts (cane, sheath leaf and leaf) were carried out. Some different cellular structures were identified in the spodogram (remaining skeleton after calcination). Major silica content was found in leaves and sheath leaves. The main element in all the ashes studied, together with oxygen, was potassium (22 to 46% depending on the part of the plant). Chloride content was also high (5¿13%), which limits their use to non-steel reinforced concrete. The pozzolanic reactivity of ADSA was assessed in pastes by thermogravimetric analysis and in mortars with ordinary Portland cement based on compressive strength development. Excellent results were found in terms of reactivity.Paya Bernabeu, JJ.; Rosello Caselles, J.; Monzó Balbuena, JM.; Escalera, A.; Santamarina Siurana, MP.; Borrachero Rosado, MV.; Soriano Martinez, L. (2018). An approach to a new supplementary cementing material: Arundo donax straw ash material. Sustainability. 10(11):1-16. https://doi.org/10.3390/su10114273S116101

Prevention of infections related to health care in primary care. Lessons from the pandemic

El sistema sanitario fall? a la hora de garantizar la seguridad tanto de los profesionales como de las personas que acudieron a los centros al inicio de la pandemia. La falta de materiales y directrices para la prevenci?n de infecciones provoc? en Espa?a la peor cat?strofe de la historia de la seguridad del paciente y de la salud laboral en el ?mbito sanitario. Sucedi? tambi?n en otros pa?ses, pero Espa?a tuvo las mayores tasas de sanitarios infectados del mundo. Fue una cat?strofe, en buena parte, evitable. Revisamos qu? medidas se han tomado para la prevenci?n de infecciones en los centros de atenci?n primaria, como la higiene de manos, las mascarillas y el material de protecci?n personal o el mantenimiento de la distancia interpersonal, entre otras. Actualizamos las recomendaciones y planteamos las perspectivas en una situaci?n que exige flexibilidad y capacidad de adaptaci?n para mantener una atenci?n de calidad y segura.The health system failed to guarantee the safety of both professionals and citizens who came to the centers at the beginning of the pandemic. The lack of materials and guidelines for the prevention of infections caused in Spain the worst catastrophe in the history of patient safety and occupational health in healthcare. It also happened in other countries but Spain had the highest rates of infected health workers in the world. It was a largely avoidable event. We review what measures have been taken to prevent infections in primary care centers, such as hand hygiene, masks and personal protection material or the maintenance of social distance, among others. We update the recommendations and raise the perspectives in a situation that requires flexibility and adaptability to maintain quality and safe care

Presencia de zearalenona en pasturas del este de Chaco

Se estudió la presencia de zearalenona en pasturas y alimentos que son utilizados para la producción de bovinos de carne de la zona este de la provincia del Chaco. Asimismo, se realizó el aislamiento e identificación de diversas especies de Fusarium y se determinó su capacidad de producir zearalenona en condiciones de laboratorio. La determinación química de la toxina se realizó mediante las metodologías HPLC y ensayo inmunoenzimático (ELISA). Se analizaron 29 muestras y en 17 de ellas se confirmó la ocurrencia natural de zearalenona en cantidades variables. Se identificaron 63 aislamientos que correspondieron a Fusarium cf. acuminatum, F. chlamydosporum, F. equiseti, F. oxysporum y F. semitectum, confirmándose además la producción in vitro de zearalenona en 34 de éstos aislamientos.Natural occurrence of zearalenone in grassland, improved pastures and feeds for cattle in eastern Chaco province (Argentina) was surveyed. Besides, isolation, identification and toxicogenic capacity of several Fusarium species were carried out. HPLC and ELISA techniques were used for detection of the toxin. In 17 of 29 samples zearalenone presence was confirmed. Sixty- three Fusarium isolates corresponding to Fusarium cf. acuminatum F. chlamydosporum, F. equiseti, F. oxysporum and F. semitectum were identified. On the other hand, in vitro production of zearalenone was verified in 34 of these isolates.Fil: Salvat, Adriana Elisabeth. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Balbuena, Osvaldo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Chaco-Formosa. Estación Experimental Agropecuaria Colonia Benítez; ArgentinaFil: Ricca, A.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Comerio, Ricardo Mario. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Rosello Brajovich, J. E.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Chaco-Formosa. Estación Experimental Agropecuaria Colonia Benítez; ArgentinaFil: Rojas, D.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Berretta, Marcelo Facundo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Delssin, E.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Chaco-Formosa. Estación Experimental Agropecuaria Colonia Benítez; ArgentinaFil: Bedascarrasbure, Enrique Luciano. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Salerno, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentin

Presencia de zearalenona en pasturas del este de Chaco

Se estudió la presencia de zearalenona en pasturas y alimentos que son utilizados para la producción de bovinos de carne de la zona este de la provincia del Chaco. Asimismo, se realizó el aislamiento e identificación de diversas especies de Fusarium y se determinó su capacidad de producir zearalenona en condiciones de laboratorio. La determinación química de la toxina se realizó mediante las metodologías HPLC y ensayo inmunoenzimático (ELISA). Se analizaron 29 muestras y en 17 de ellas se confirmó la ocurrencia natural de zearalenona en cantidades variables. Se identificaron 63 aislamientos que correspondieron a Fusarium cf. acuminatum, F. chlamydosporum, F. equiseti, F. oxysporum y F. semitectum, confirmándose además la producción in vitro de zearalenona en 34 de éstos aislamientos.Natural occurrence of zearalenone in grassland, improved pastures and feeds for cattle in eastern Chaco province (Argentina) was surveyed. Besides, isolation, identification and toxicogenic capacity of several Fusarium species were carried out. HPLC and ELISA techniques were used for detection of the toxin. In 17 of 29 samples zearalenone presence was confirmed. Sixty- three Fusarium isolates corresponding to Fusarium cf. acuminatum F. chlamydosporum, F. equiseti, F. oxysporum and F. semitectum were identified. On the other hand, in vitro production of zearalenone was verified in 34 of these isolates.Fil: Salvat, Adriana Elisabeth. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Balbuena, Osvaldo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Chaco-Formosa. Estación Experimental Agropecuaria Colonia Benítez; ArgentinaFil: Ricca, A.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Comerio, Ricardo Mario. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Rosello Brajovich, J. E.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Chaco-Formosa. Estación Experimental Agropecuaria Colonia Benítez; ArgentinaFil: Rojas, D.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Berretta, Marcelo Facundo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Delssin, E.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Chaco-Formosa. Estación Experimental Agropecuaria Colonia Benítez; ArgentinaFil: Bedascarrasbure, Enrique Luciano. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Salerno, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentin

Chlorhexidine Substantivity on Salivary Flora and Plaque-Like Biofilm: An In Situ Model

This work was supported by project FIS PI11/01383 from Carlos III Institute of Health (Ministry of Economy and Competitiveness, Madrid, Spain

The origin and speciation of orchids

SummaryOrchids constitute one of the most spectacular radiations of flowering plants. However, their origin, spread across the globe, and hotspots of speciation remain uncertain due to the lack of an up-to-date phylogeographic analysis.We present a new Orchidaceae phylogeny based on combined high-throughput and Sanger sequencing data, covering all five subfamilies, 17/22 tribes, 40/49 subtribes, 285/736 genera, and c. 7% (1921) of the 29 524 accepted species, and use it to infer geographic range evolution, diversity, and speciation patterns by adding curated geographical distributions from the World Checklist of Vascular Plants.The orchids' most recent common ancestor is inferred to have lived in Late Cretaceous Laurasia. The modern range of Apostasioideae, which comprises two genera with 16 species from India to northern Australia, is interpreted as relictual, similar to that of numerous other groups that went extinct at higher latitudes following the global climate cooling during the Oligocene. Despite their ancient origin, modern orchid species diversity mainly originated over the last 5 Ma, with the highest speciation rates in Panama and Costa Rica.These results alter our understanding of the geographic origin of orchids, previously proposed as Australian, and pinpoint Central America as a region of recent, explosive speciation