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Tridentate acylhydrazone copper(II) complexes with heterocyclic bases as coligands. Synthesis, spectroscopic studies, crystal structure and cytotoxicity assays
No full textTwo new penta-coordinated copper(II) hydrazone coordination compounds with 2,2́ bipyridine (I) or 1,10 phenanthroline (II) as coligands are synthesized and characterized in the solid state and in solution by spectroscopic methods (FTIR, Raman, UV–vis, EPR). Single crystal X-ray studies show that they have closely related molecular structures with the copper center in a distorted square pyramidal O2N3 environment. The N-acylhydrazone, 4-hydroxy-NŃ-(E)2-hydroxy-3-methoxybenzylidene]benzohydrazide, H2L, coordinates tridentate through its ONO donor atoms as monoanion (HL-) in the cationic complex (I), [Cu(HL)(bipy)](NO3). During the period that takes the synthesis reaction of compound (II), [Cu(L)(o-phen)] to complete, keto-amine to enol-imine tautomerization of H2L occurs and the hydrazone coordinates tridentate as dianionic ligand (L2-). The fivefold coordination sphere of the complexes is completed with the nitrogen atoms of the respective coligands. Cytotoxicity studies against bone (MG-63, IC50(I) = 5.6 ± 1.0 , IC50(II) = 3.5 ± 0.3), breast (MCF7, IC50(I) = 10.8 ± 1.9, IC50(II) = 4.0 ± 1.3), (MDA-MB-231, IC50(I) = 11.4 ± 0.6, IC50(II) = 5.3 ± 0.2) and lung cancer cells (A549, IC50(I) = 7.7 ± 0.7, IC50(II) = 7.0 ± 0.4) reveals increased effectiveness of both complexes compared with the free ligand, the copper nitrate salt and the reference metallodrug cisplatin (CDDP).This work was supported by CONICET-CCT-La Plata (PIP: 0340, 0651), UNLP (Grant: 11/X673, 11/041, 11/857), ANPCyT (PICT 2016–1574), Argentina, and by Junta de Castilla y León and FEDER BU291P18 and BU049P20, Ministerio de Economía y Competitividad CTQ2016-75023-C2-1-P, Fundación Bancaria Caixa D. Etalvis I Pensions de Barcelona La Caixa-UBU001 and European Union H2020-LC-SC3-2020-NZE-RES-CC Nefertiti Project, of Spain
Modificación de la retracción y las propiedades mecánicas en hormigones mediante la adición de escorias de horno de cuchara
No full textTrabajo presentado en: VIII Jornadas de Doctorandos de la Universidad de Burgos, realizado en los días 25 y 26 de abril de 2022, organizado por la Universidad de Burgos (España)La disminución de la humedad en un elemento de hormigón debido
a una diferencia de humedad relativa entre el medio ambiente y el elemento
en sí provoca una deformación volumétrica de contracción (disminución de
volumen). Este fenómeno, denominado retracción por secado, puede provocar
la aparición de grietas en el hormigón, lo que a su vez puede conducir a una
disminución de la resistencia y de la durabilidad del elemento estructural. Una
estrategia para disminuir la retracción es la adición durante el hormigonado de
escorias de horno de cuchara al presentar este tipo de escoria características
expansivas. La escoria de horno de cuchara (Ladle Furnace Slag -LFS) es un
subproducto de la industria acerera, por lo que su utilización para la mejora
de hormigones tiene también un efecto beneficioso en el medio ambiente al
eliminar residuos de la cadena de producción. Debido a que la adición de
escorias conlleva una variación de las propiedades mecánicas del hormigón
además de una disminución de la retracción, es conveniente evaluar de forma
precisa esa modificación de las propiedades al añadir diferentes proporciones
de estas escorias, de manera que se pueda establecer la cantidad óptima de
LFS que puede ser añadida manteniendo las propiedades del hormigón por
encima de los límites exigibles. Por ello, esta investigación evalúa la modificación de la retracción y la variación de dos propiedades mecánicas: resistencia a compresión simple y resistencia a flexión, a edades tempranas de curado,
7 y 28 días, cuando se añade una proporción de LFS del 5% y del 20%. Los
resultados muestran una disminución de la retracción pero también una modificación de la resistencia a compresión simple y la resistencia a flexión según
la edad contemplada y la proporción de escoria empleada.This research work was supported by the Spanish Ministry of Universities, MICINN, AEI, EU, ERDF and NextGenerationEU [grant numbers PID2020-113837RB-I00; 10.13039/501100011033; TED2021-129715B-I00]; the Junta de Castilla y León (Regional Government) and ERDF [grant number UIC-231]; and the University of Burgos [grant number SUCONS, Y135.GI]
Mean body size estimation in large mammals and the computation of biomass in past ecosystems: An application to the Pleistocene sites of Orce and Sierra de Atapuerca (Spain)
No full textEstimates of adult body mass are usually considered as equivalent of mean population body size in most studies of ancient mammals. However, given that any population is composed in part of subadult individuals, this approach overestimates the mean population body mass and biomass. For this reason, more realistic estimates of mean population body mass should be used. In this paper, we: 1) test five different proxies of population mean mass; and 2) estimate the total prey biomass in the paleoecosystems from the Orce and Atapuerca sites as an approach for estimating their carrying capacity. Our results for past ecosystems support the use of survival profiles derived from the Weibull model (SPW), as they show values in better agreement with those of extant populations. They also estimate higher carrying capacities for the faunal assemblages of Orce than for those of Atapuerca. We suggest that the environmental conditions of Orce could have played an important role in the first peopling of Europe.Estimation de la taille moyenne des grands mammifères et calcul de la biomasse dans les écosystèmes du passé : une application aux sites pléistocènes de l’Orce et de la Sierra de Atapuerca (Espagne).
Les estimations de la masse corporelle des adultes sont généralement considérées comme équivalentes
à la masse corporelle moyenne de la population dans la plupart des études paléoécologiques des mammifères anciens. Cependant, étant donné que toute population est composée en partie d’individus
subadultes, cette approche surestime la masse corporelle et la biomasse moyennes de la population.
C’est pourquoi il convient d’utiliser des estimations plus réalistes de la masse corporelle moyenne de la
population. Dans cet article, nous : 1) testons cinq différentes approximations de la masse corporelle
moyenne de la population; et 2) estimons la biomasse totale des proies dans les paléoécosystèmes
des sites d’Orce et d’Atapuerca comme approche pour estimer leur capacité de charge. Nos résultats
pour les écosystèmes passés soutiennent l’utilisation des profils de survie dérivés du modèle de Weibull (SPW), car ils montrent des valeurs en meilleur accord avec celles des populations existantes. Ils
estiment également des capacités de charge plus élevées pour les assemblages fauniques de l’Orce que
pour ceux de l’Atapuerca. Nous suggérons que les conditions environnementales de l’Orce pourraient
avoir joué un rôle important dans le premier peuplement de l’Europe.This research was financed by the Ministry of Economy and Competitiveness (MINECO) of the Spanish Government (grants CGL2016-78577-P, CGL2016-80975-P, and PGC2018-093925-B-C31), the Generalitat de Catalunya (grant GENCAT 2017SGR 859), and by the program IdEx Bordeaux “Investments for the future”, financed by Agence nationale de la Recherche of France (ref. ANR No.-10- IDEX-03-02). G. Rodríguez-Gómez is supported by a “Juan de la Cierva-formación” postdoctoral contract (FJCI-2016- 28652) from the Ministry of Economy and Competitiveness (MINECO) of the Spanish Government and by an ‘‘Atracción de Talento’’ postdoctoral contract (2019-T2/HUM-13370) from “Comunidad de Madrid/Universidad Complutense” for developing the project ‘‘Estudios paleoecológicos en los yacimientos de Orce y de la sierra de Atapuerca’’
The Redox‐Mediated Nickel–Metal Hydride Flow Battery
Get PDFEach battery technology possesses intrinsic advantages and disadvantages, e.g., nickel–metal hydride (MH) batteries offer relatively high specific energy and power as well as safety, making them the power of choice for hybrid electric vehicles, whereas aqueous organic flow batteries (AORFBs) offer sustainability, simple replacement of their active materials and independent scalability of energy and power, making them very attractive for stationary energy storage. Herein, a new battery technology that merges the above mentioned battery technologies through the use of redox-mediated reactions is proposed that intrinsically possesses the main features of each separate technology, e.g., high energy density of the solid active materials, easy recyclability, and independent scalability of energy and power. To achieve this, Ni(OH)2 and MHs are confined in the positive and negative reservoirs of an AORFB that employs alkaline solutions of potassium ferrocyanide and a mixture of 2,6-dihydroxyanthraquinone and 7,8-dihydroxyphenazine-2-sulfonic acid as catholyte and anolyte, respectively. An energy density of 128 Wh L–1 is achieved based on the capacity of the reservoirs leaving ample room for improvement up to the theoretical limit of 378 Wh L–1. This new battery technology opens up new market opportunities never before envisaged, for redox flow batteries, e.g., domestic energy storage and heavy-duty vehicle transportation.Spanish Government through the Research Challenges Programme (Grant No. RTI2018-099228-A-I00). E.V. thanks the MINECO for the financial support (RYC2018-026086-I)
Mechanical performance and autogenous and drying shrinkage of MgO-based recycled aggregate high-performance concrete
Get PDFThe high strength and durability of high-performance concrete (HPC) may be significantly reduced by shrinkage cracking. The use of reactive magnesium oxide (MgO) can reduce shrinkage of cement-based materials due to its expansive properties. This study intends to analyse the validity of MgO as shrinkage-reducing agent in recycled aggregate HPC. To do so, ten HPC mixes with 0%, 25%, and 100% of both early-age (7-days air curing) and matured (6-month air curing) RA were produced. In half of the mixes, 10% ordinary Portland cement was replaced with MgO. The use of MgO slightly worsened the mechanical behaviour of HPC, especially when combined with large amounts of RA. On the other hand, the expansion of MgO fully offset the autogenous shrinkage of HPC and reduced total shrinkage by around 20–40%. Water storage of RA, and its deferred release over time, produced a more efficient hydration of MgO, which in turn led to a further reduction of autogenous shrinkage. However, the increase of drying shrinkage caused by RA was greater than this decrease of autogenous shrinkage due to MgO, so the higher the RA content of HPC the lower the total shrinkage reduction when adding MgO. Thus, the decrease of total shrinkage caused by MgO was compensated by the shrinkage increase because of RA when adding amounts above 35% early-age RA and 42% matured RA. Therefore, despite the suitability of MgO as shrinkage-reducing agent in recycled aggregate HPC, its effectiveness was reduced with increasing amounts of RA.Spanish Ministry of Universities, MICINN, AEI and ERDF [grant numbers FPU17/03374; EST19/00263; PID2020-113837RB-I00; 10.13039/501100011033]. The authors also acknowledge the support of the Foundation for Science and Technology, CERIS Research Centre and Instituto Superior Técnico, the Junta de Castilla y León [grant number UIC231], and the University of Burgos [grant number Y135.GI]
Tuning the properties of ionic liquids by mixing with organic solvents: The case of 1-butyl-3-methylimidazolium glutamate with alkanols
Get PDFBinary liquid mixtures of 1-butyl-3-methylimidazolium glutamate acid ([bmim][glu]) with alkanols (1-propanol, isobutanol and 1,2-propanediol) are studied in the full composition range as a function of temperature using a combined experimental and computational chemistry approach. Experimental thermophysical information as well as derived excess and mixing properties allowed to characterize these complex liquid mixtures in terms of deviation from ideality as well their relationships with the developed intermolecular forces and changes with the type of considered alkanols. Theoretical studies using quantum chemistry and classical molecular dynamics simulations provided nanoscopic characterization on the studied fluids, with particular attention to the extension and nature of hydrogen bonding and its effects on molecular arrangements and mixed fluids’ properties. The reported study provides a micro and macroscopic characterization of the considered aminoacid-based ionic liquid mixtures, thus contributing to the knowledge of sustainable ionic liquid systems mixed with organic solvents for fine tuning properties and developing task specific applications.Shiraz University of Technology and Ministerio de Ciencia, Innovación y Universidades (Spain, project RTI2018-101987-B-I00)
Comparative study of classification algorithms for quality assessment of resistance spot welding joints from preand post-welding inputs
Get PDFResistance spot welding (RSW) is a widespread manufacturing process in the automotive industry. There are different approaches for assessing the quality level of RSW joints. Multi-input-single-output methods, which take as inputs either the intrinsic parameters of the welding process or ultrasonic nondestructive testing variables, are commonly used. This work demonstrates that the combined use of both types of inputs can significantly improve the already competitive approach based exclusively on ultrasonic analyses. The use of stacking of tree ensemble models as classifiers dominates the classification results in terms of accuracy, F-measure and area under the receiver operating characteristic curve metrics. Through variable importance analyses, the results show that although the welding process parameters are less relevant than the ultrasonic testing variables, some of the former provide marginal information not fully captured by the latter.This work was supported in part by the Spanish Ministry of Science, Innovation and Universities (Excellence Networks) under Grant HAR2017-90883-REDC and Grant RED2018-102518-T, and in part by the Junta de Castilla y León Consejería de Educación under Grant BDNS 425389. The work of Virginia Ahedo was supported by the European Social Fund