61 research outputs found

    Effect of alkanolamines in kaolinitic calcined clays pozzolanic reactivity.

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    Five kaolinitic clays with different amounts of kaolinite, ranging between ~70 wt% and ~30 wt%, have been studied to unravel the possible activation effect of alkanolamines on the aluminate fraction of calcined clays. This is of interest for enhancing the reactivity of LC3 binders. These clays were calcinated at 860ºC for 4 h and ground to particle sizes of DV,50 ~10 μm. Three alkanolamines were selected: triisopropanolamine (TIPA), triethanolamine (TEA) and methyldiethanolamine (MDEOA), added in two dosages, 0.025 and 0.050 wt% (by weight of calcined clay, bwcc). The role of alkanolamines as activators in calcined clays was assessed following the ASTM c1897 standard bases on R3-tests. Concretely, first by measuring the heat evolved due to the pozzolanic reaction of the calcined clay and Ca(OH)2 (i.e. R3 mixture) by isothermal calorimetry at 40ºC during 7 days, and second, the bounded water by measuring the weight loss of R3 mixture after heating them at 350ºC.This study concludes that there is no significant activation of the pozzolanic activity of kaolinitic calcined clays just by adding alkanolamines. However, a mild activation was observed, i.e., higher heat evolved up to 7 days, by adding 0.05 wt% bwcc of TIPA, TEA and MDEOA to a high kaolinite content disordered metakaolin with high specific surface area calcined clay.PID2020-114650RB-I00 CTS cement corporation Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Pozzolanic materials to reduce CO2 emissions: local solutions for a global issue.

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    Abstract de una keynote invitada.In recent decades, the cement sector has been looking for solutions to reduce the carbon footprint, being one of the most promising strategies, the replacement of clinker with supplementary cementitious materials, SCMs. However, the main limitation of this approach is the availability of suitable SCMs. This work presents the study of three families of pozzolanic materials, Spanish calcined clays (CC), Natural Pozzolans (NP) and fly ashes (FA). The characterization of each family will be presented, with emphasis on the kaolinite content of the original clays and the amorphous contents of the natural pozzolans and fly ashes. The results of the pozzolanic prediction tests will be compared: strength activity index, SAI, and R3 test according to ASTM C1897-20. The SAI test has two important limitations: i) it gives false positives at 28 days, as does the addition of quartz (Qz) and ii) a minimum of 28 days is required to obtain the pozzolanic activity results. In addition, the R3 test has proved to be useful in ruling out inert additions, such as quartz. Moreover, it presents a very good correlation between the heat emitted and the combined water at 7 days and the amount of kaolinite in clays or amorphous in ashes. However, the absolute values of heat and combined water cannot be compared between different families. That is, in the calcined clay family, it can be inferred that if the kaolinite content is higher than 50 wt%, the heat released should be between 500-700 J/g, whereas a fly ash with an amorphous content of around 70 wt% will release between 200-250 J/g.PID2020-114650RB-I00 grant from Spanish government, Master Builders Solutions Deutschland GmbH (Germany) and Buzzi Unicem SpA (Italy) are thanked for the funding. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Plan de contingencia para los servicios de medicina intensiva frente a la pandemia COVID-19

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    In January 2020, the Chinese authorities identified a new virus of the Coronaviridae family as the cause of several cases of pneumonia of unknown aetiology. The outbreak was initially confined to Wuhan City, but then spread outside Chinese borders. On 31 January 2020, the first case was declared in Spain. On 11 March 2020, The World Health Organization (WHO) declared the coronavirus outbreak a pandemic. On 16 March 2020, there were 139 countries affected. In this situation, the Scientific Societies SEMICYUC and SEEIUC, have decided to draw up this Contingency Plan to guide the response of the Intensive Care Services. The objectives of this plan are to estimate the magnitude of the problem and identify the necessary human and material resources. This is to provide the Spanish Intensive Medicine Services with a tool to programme optimal response strategies

    Extinction risk of Mesoamerican crop wild relatives

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    Ensuring food security is one of the world's most critical issues as agricultural systems are already being impacted by global change. Crop wild relatives (CWR)—wild plants related to crops—possess genetic variability that can help adapt agriculture to a changing environment and sustainably increase crop yields to meet the food security challenge. Here we report the results of an extinction risk assessment of 224 wild relatives of some of the world's most important crops (i.e. chilli pepper, maize, common bean, avocado, cotton, potato, squash, vanilla and husk tomato) in Mesoamerica—an area of global significance as a centre of crop origin, domestication and of high CWR diversity. We show that 35% of the selected CWR taxa are threatened with extinction according to The International Union for Conservation of Nature (IUCN) Red List demonstrates that these valuable genetic resources are under high anthropogenic threat. The dominant threat processes are land use change for agriculture and farming, invasive and other problematic species (e.g. pests, genetically modified organisms) and use of biological resources, including overcollection and logging. The most significant drivers of extinction relate to smallholder agriculture—given its high incidence and ongoing shifts from traditional agriculture to modern practices (e.g. use of herbicides)—smallholder ranching and housing and urban development and introduced genetic material. There is an urgent need to increase knowledge and research around different aspects of CWR. Policies that support in situ and ex situ conservation of CWR and promote sustainable agriculture are pivotal to secure these resources for the benefit of current and future generations

    VIII Encuentro de Docentes e Investigadores en Historia del Diseño, la Arquitectura y la Ciudad

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    Acta de congresoLa conmemoración de los cien años de la Reforma Universitaria de 1918 se presentó como una ocasión propicia para debatir el rol de la historia, la teoría y la crítica en la formación y en la práctica profesional de diseñadores, arquitectos y urbanistas. En ese marco el VIII Encuentro de Docentes e Investigadores en Historia del Diseño, la Arquitectura y la Ciudad constituyó un espacio de intercambio y reflexión cuya realización ha sido posible gracias a la colaboración entre Facultades de Arquitectura, Urbanismo y Diseño de la Universidad Nacional y la Facultad de Arquitectura de la Universidad Católica de Córdoba, contando además con la activa participación de mayoría de las Facultades, Centros e Institutos de Historia de la Arquitectura del país y la región. Orientado en su convocatoria tanto a docentes como a estudiantes de Arquitectura y Diseño Industrial de todos los niveles de la FAUD-UNC promovió el debate de ideas a partir de experiencias concretas en instancias tales como mesas temáticas de carácter interdisciplinario, que adoptaron la modalidad de presentación de ponencias, entre otras actividades. En el ámbito de VIII Encuentro, desarrollado en la sede Ciudad Universitaria de Córdoba, se desplegaron numerosas posiciones sobre la enseñanza, la investigación y la formación en historia, teoría y crítica del diseño, la arquitectura y la ciudad; sumándose el aporte realizado a través de sus respectivas conferencias de Ana Clarisa Agüero, Bibiana Cicutti, Fernando Aliata y Alberto Petrina. El conjunto de ponencias que se publican en este Repositorio de la UNC son el resultado de dos intensas jornadas de exposiciones, cuyos contenidos han posibilitado actualizar viejos dilemas y promover nuevos debates. El evento recibió el apoyo de las autoridades de la FAUD-UNC, en especial de la Secretaría de Investigación y de la Biblioteca de nuestra casa, como así también de la Facultad de Arquitectura de la UCC; va para todos ellos un especial agradecimiento

    Gestión del conocimiento: perspectiva multidisciplinaria. Volumen 12

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    El libro “Gestión del Conocimiento. Perspectiva Multidisciplinaria”, Volumen 12, de la Colección Unión Global, es resultado de investigaciones. Los capítulos del libro, son resultados de investigaciones desarrolladas por sus autores. El libro cuenta con el apoyo de los grupos de investigación: Universidad Sur del Lago “Jesús María Semprúm” (UNESUR), Zulia – Venezuela; Universidad Politécnica Territorial de Falcón Alonso Gamero (UPTAG), Falcón – Venezuela; Universidad Politécnica Territorial de Mérida Kleber Ramírez (UPTM), Mérida – Venezuela; Universidad Guanajuato (UG) - Campus Celaya - Salvatierra - Cuerpo Académico de Biodesarrollo y Bioeconomía en las Organizaciones y Políticas Públicas (C.A.B.B.O.P.P), Guanajuato – México; Centro de Altos Estudios de Venezuela (CEALEVE), Zulia – Venezuela, Centro Integral de Formación Educativa Especializada del Sur (CIFE - SUR) - Zulia - Venezuela, Centro de Investigaciones Internacionales SAS (CIN), Antioquia - Colombia.y diferentes grupos de investigación del ámbito nacional e internacional que hoy se unen para estrechar vínculos investigativos, para que sus aportes científicos formen parte de los libros que se publiquen en formatos digital e impreso

    Heterochromatin Protein 1 controls gene expression and longevity upon prohibitin depletion

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    Trabajo presentado en el VIII Spanish Worm Meeting, celebrado en Logroño (España) del 21 al 22 de octubre de 2022.Prohibitins (PHB) form a multimeric structure at the mitochondrial inner membrane. PHB deficiency shortens the lifespan of wild type Caenorhabditis elegans nematodes, but dramatically extends that of insulin signalling receptor (daf-2) mutants. This phenotype is accompanied by a differential induction of the mitochondrial Unfolded Protein Response (UPRmt) that is attenuated in daf-2 mutants. In a genome wide RNAi screen, we identified Heterochromatin Protein Like 1 (HPL-1) as a new regulator of the UPRmt. Under normal conditions, hpl-1 null mutants live longer than wild type worms and show a mild induction of the UPRmt, which depends on canonical UPRmt transcription factors. We observed mitochondrial fragmentation and reduced respiration in hpl-1 mutants, which together with a marked sensitivity to mitochondrial translation inhibition suggests a mitochondrial dysfunction. Remarkably, under mitochondrial stress by PHB depletion, hpl-1 null mutants showed an increased lifespan compared to wild type animals and a reduced UPRmt. Moreover, the reduced respiration of PHB depleted animals was fully recovered in hpl-1 null mutants. Interestingly, HPL-1 was required for the increased lifespan and the attenuated UPRmt of daf-2 PHB-depleted worms. Upon PHB depletion, HPL-1 protein levels increase in hypodermal tissue, supporting the relevance of HPL-1 in mounting the stress response. Additionally, in the absence of stress HPL-1 levels increase as animals age, suggesting a role in longevity regulation. In order to study genes targeted by HPL-1, we examined its binding profile in hypodermal tissue by DamID under non-stress and mitochondrial stress conditions in wild type and daf-2 mutants. HPL-1 associates to coding and upstream regions with and without stress. We uncovered ~40% and 70% of HPL-1-unique bound genes upon mitochondrial stress in wild type and insulin signalling mutants, respectively. Among them, a significant group of genes are commonly regulated by HPL-1 and key stress transcription factors and epigenetic regulators under the different conditions. Our data shows for the first time a role for HP1 proteins in controlling gene expression in response to mitochondrial dysfunction to modulate lifespan

    Heterochromatin protein 1 regulates longevity and the mitochondrial unfolded protein response

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    Trabajo presentado en Cell Symposia: Multifaceted Mitochondria, celebrado en Sevilla (España) del 06 al 08 de noviembre de 2022.Prohibitins (PHB) form a multimeric structure at the mitochondrial inner membrane. PHB deficiency shortens the lifespan of wild type Caenorhabditis elegans nematodes, but dramatically extends that of insulin signalling receptor (daf-2) mutants. This phenotype is accompanied by a differential induction of the mitochondrial Unfolded Protein Response (UPRmt) that is attenuated in daf-2 mutants. We identified Heterochromatin Protein Like 1 (HPL-1) as a new regulator of the UPRmt and mediator of the opposing longevity phenotype caused by PHB depletion. We report functional and structural impairments of mitochondria when HP1 is depleted from worm and human cells, showing a conservation of function. We uncovered ~70% of differently bound genes by HPL-1 upon mitochondrial stress and determined HPL-1-dependent tissue-specific alterations in gene expression in hypodermal cells. Our data shows for the first time a role for HP1 proteins in controlling gene expression in response to mitochondrial dysfunction to modulate lifespan

    Influence of Polysaccharides’ Molecular Structure on the Antibacterial Activity and Cytotoxicity of Green Synthesized Composites Based on Silver Nanoparticles and Carboxymethyl-Cellulose

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    In this paper we report on the influence of polysaccharides’ molecular structure on the antibacterial activity and cytotoxicity of composites based on silver nanoparticles (AgNPs) immobilized into carboxymethyl-cellulose (CMC). These composites were green synthesized from the reduction of silver ions into aqueous solutions of the polysaccharide, using CMC with different degree of substitution (DS) and molecular weight (Mw). The composites were characterized by transmission electron microscopy (TEM), as well as infrared (ATR-FTIR), ultraviolet (UV-Vis), Raman, and X-ray photo-electron (XPS) spectroscopic techniques. The antibacterial activity was evaluated with minimum inhibitory concentration against Enterococcus faecalis. The cytotoxicity of composites was assessed against human gingival fibroblast. Experimental evidence suggests that particle size distribution and morphology of AgNPs change according to the quantity of silver precursor added to the reaction, as well as the DS and Mw of CMC used for composites preparation. This is related to the dispersion of silver precursor into aqueous solutions of the polysaccharide and the formation of Ag-O coordination bonds among AgNPs and COO− moieties of CMC. Moreover, these coordination bonds modify the ability of nanoparticles to produce and release Ag+ into aqueous dispersion, adjusting their antibacterial activity and the induction of cytotoxicity into the tested biological environments
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