Structure-property relationships in metal-organic frameworks for hydrogen storage

Experimental hydrogen isotherms on several metal-organic frameworks (IRMOF-1, IRMOF-3, IRMOF-9, ZIF-7, ZIF-8, ZIF-9, ZIF-11, ZIF-12, ZIF-CoNIm, MIL-101 (Cr), NH2-MIL-101 (Cr), NH2-MIL-101 (Al), UiO-66, UiO-67 and HKUST-1) synthesized in-house and measured at 77 K and pressures up to 18 MPa are presented, along with N2 adsorption characterization. The experimental isotherms together with literature high pressure hydrogen data were analyzed in order to search for relationships between structural properties of the materials and their hydrogen uptakes. The total hydrogen capacity of the materials was calculated from the excess adsorption assuming a constant density for the adsorbed hydrogen. The surface area, pore volumes and pore sizes of the materials were related to their maximum hydrogen excess and total hydrogen capacities. Results also show that ZIF-7 and ZIF-9 (SOD topology) have unusual hydrogen isotherm shapes at relatively low pressures, which is indicative of "breathing", a phase transition in which the pore space increases due to adsorption. This work presents novel correlations using the modelled total hydrogen capacities of several MOFs. These capacities are more practically relevant for energy storage applications than the measured excess hydrogen capacities. Thus, these structural correlations will be advantageous for the prediction of the properties a MOF will need in order to meet the US Department of Energy targets for the mass and volume capacities of on-board storage systems. Such design tools will allow hydrogen to be used as an energy vector for sustainable mobile applications such as transport, or for providing supplementary power to the grid in times of high demand.</p

Isosteric enthalpies for hydrogen adsorbed on nanoporous materials at high pressures

A sound understanding of any sorption system requires an accurate determination of the enthalpy of adsorption. This is a fundamental thermodynamic quantity that can be determined from experimental sorption data and its correct calculation is extremely important for heat management in adsorptive gas storage applications. It is especially relevant for hydrogen storage, where porous adsorptive storage is regarded as a competing alternative to more mature storage methods such as liquid hydrogen and compressed gas. Among the most common methods to calculate isosteric enthalpies in the literature are the virial equation and the Clausius-Clapeyron equation. Both methods have drawbacks, for example, the arbitrary number of terms in the virial equation and the assumption of ideal gas behaviour in the Clausius-Clapeyron equation. Although some researchers have calculated isosteric enthalpies of adsorption using excess amounts adsorbed, it is arguably more relevant to applications and may also be more thermodynamically consistent to use absolute amounts adsorbed, since the Gibbs excess is a partition, not a thermodynamic phase. In this paper the isosteric enthalpies of adsorption are calculated using the virial, Clausius-Clapeyron and Clapeyron equations from hydrogen sorption data for two materials-activated carbon AX-21 and metal-organic framework MIL-101. It is shown for these two example materials that the Clausius-Clapeyron equation can only be used at low coverage, since hydrogen's behaviour deviates from ideal at high pressures. The use of the virial equation for isosteric enthalpies is shown to require care, since it is highly dependent on selecting an appropriate number of parameters. A systematic study on the use of different parameters for the virial was performed and it was shown that, for the AX-21 case, the Clausius-Clapeyron seems to give better approximations to the exact isosteric enthalpies calculated using the Clapeyron equation than the virial equation with 10 variable parameters

Flexible ZIFs - probing guest-induced flexibility with CO2 , N2 and Ar adsorption

Background The effect of framework topology on the guest‐induced flexibility of several crystalline zeolitic imidazolate frameworks (ZIF‐7, ZIF‐9, ZIF‐11 and ZIF‐12) was investigated via analysis of experimental N2, CO2 and Ar isotherms at 77 K (N2 and Ar) and 273 K (CO2) for gas pressures up to 0.13 MPa. Results The experimental isotherms were analysed in order to investigate structural flexibility of these materials using gases with kinetic diameters equal to or larger than the diameters of their static pore apertures. The results of gas sorption measurements indicate guest‐induced phase changes for ZIF‐7 and ZIF‐9 (SOD topologies). ZIF‐12 (RHO topology) also shows uptake for gases, despite its pore limiting diameter being smaller than the kinetic diameters of the adsorbed molecules. Conclusions This work highlights the ability of ZIFs with different framework topologies to change their structure and increase their pore aperture upon interaction with certain gases. These findings are key in the development of more selective ZIF‐based materials for important industrial applications including low‐energy gas separations, catalytic nanoreactors and sensor technology

Estudio de caso sobre la aplicación de un programa de aprendizaje con tecnología 3D en las aulas de educación infantil

The school world has had to face many challenges, such as new learning models, new procedures and teaching strategies.A study is presented on the implementation of a learning program with the use of emerging 3D technologies in the classrooms of Early Childhood Education.The methodology used is mixed, that is to say, with a quantitative methodology the evaluation of the results of the implemented learning program is carried out, as well as knowing, through a qualitative analysis, the perception of the teaching staff in the implementation of the teaching program-learning and its training about new technologies.The program has been carried out in a classroom of the third year of Early Childhood Education (nº = 20) with students between 5 and 6 years of age.The following conclusions were obtained: most of the items analyzed are above the average, finding the differentiation between 2D and 3D as the lowest item, and highlighting how very viable the use of these at early ages, where most of them They developed without major problems.Regarding the information collected on the perception of the teaching staff, we observed how most of them would be interested in knowing how to use this emerging technology, and highlighted the need for more training in this field.El mundo escolar ha tenido que hacer frente a numerosos desafíos como, por ejemplo, nuevos modelos de aprendizajes, nuevos procedimientos y estrategias didácticas.Se presenta un estudio sobre la implementación de un programa de aprendizaje con el uso de las tecnologías emergentes 3D en las aulas de Educación Infantil.La metodología utilizada tiene carácter mixto, es decir, con una metodología cuantitativa se procede a la evaluación de los resultados del programa de aprendizaje implementado, además de conocer, a través de un análisis cualitativo, la percepción del profesorado en la implementación del programa de enseñanza-aprendizaje y su formación acerca de las nuevas tecnologías.El programa se ha llevado a cabo en un aula de tercer curso de Educación Infantil (nº=20) con alumnado de entre 5 y 6 años de edad.Se obtuvo las siguientes conclusiones: la mayoría de los ítems analizados están por encima de la media, encontrando la diferenciación entre 2D al 3D como el ítem más bajo, y destacar como muy viable el uso de estas en edades tempranas, donde la mayoría de ellos se desenvolvieron sin mayores problemas. En cuanto a la información recabada sobre la percepción del profesorado, observamos como la mayoría de ellos estarían interesados en saber utilizar esta tecnología emergente, y destacaban que la necesidad de más formación en este ámbito

Lecciones básicas de Derecho e instituciones de la Unión Europea

Los materiales docentes que aquí se presentan pretenden ser un texto de ayuda y consulta para aquellos que se acercan al Derecho de la Unión Europea; en ellos no sólo se contienen los conceptos básicos de la materia, sino que se han añadido a éstos, una serie de actividades didácticas y formativas específicamente orientadas al estudiante, y que le han de servir como instrumento para poder asentar sus conocimientos mediante la realización de prácticas y autoevaluaciones.The teaching materials presented here are intended as a help text and consultation for those who come to the European Union law; they not only contain the basic concepts of matter, but that have been added to these, a series of educational activities and training specifically geared toward the student, and that you have to serve as the instrument to be able to hone their knowledge through practical work and self-evaluations

Neonatal overfeeding during lactation rapidly and permanently misaligns the hepatic circadian rhythm and programmes adult NAFLD

Childhood obesity is a strong risk factor for adult obesity, type 2 diabetes, and cardiovascular disease. The mechanisms that link early adiposity with late-onset chronic diseases are poorly characterised. We developed a mouse model of early adiposity through litter size reduction. Mice reared in small litters (SLs) developed obesity, insulin resistance, and hepatic steatosis during adulthood. The liver played a major role in the development of the disease. Objective: To gain insight into the molecular mechanisms that link early development and childhood obesity with adult hepatic steatosis and insulin resistance. Methods: We analysed the hepatic transcriptome (Affymetrix) of control and SL mice to uncover potential pathways involved in the long-term programming of disease in our model. Results: The circadian rhythm was the most significantly deregulated Gene Ontology term in the liver of adult SL mice. Several core clock genes, such as period 1e3 and cryptochrome 1e2, were altered in two-week-old SL mice and remained altered throughout their life course until they reached 4e6 months of age. Defective circadian rhythm was restricted to the periphery since the expression of clock genes in the hypothalamus, the central pacemaker, was normal. The period-cryptochrome genes were primarily entrained by dietary signals. Hence, restricting food availability during the light cycle only uncoupled the central rhythm from the peripheral and completely normalised hepatic triglyceride content in adult SL mice. This effect was accompanied by better re-alignment of the hepatic period genes, suggesting that they might have played a causal role in mediating hepatic steatosis in the adult SL mice. Functional downregulation of Per2 in hepatocytes in vitro confirmed that the period genes regulated lipid-related genes in part through peroxisome proliferator-activated receptor alpha (Ppara). Conclusions: The hepatic circadian rhythm matures during early development, from birth to postnatal day 30. Hence, nutritional challenges during early life may misalign the hepatic circadian rhythm and secondarily lead to metabolic derangements. Specific time-restricted feeding interventions improve metabolic health in the context of childhood obesity by partially re-aligning the peripheral circadian rhythm

The status of cryptococcosis in Latin America

Cryptococcosis is a life-threatening fungal infection caused by the encapsulated yeasts Cryptococcus neoformans and C. gattii, acquired from the environment. In Latin America, as occurring worldwide, C. neoformans causes more than 90% of the cases of cryptococcosis, affecting predominantly patients with HIV, while C. gattii generally affects otherwise healthy individuals. In this region, cryptococcal meningitis is the most common presentation, with amphotericin B and fluconazole being the antifungal drugs of choice. Avian droppings are the predominant environmental reservoir of C. neoformans, while C. gattii is associated with several arboreal species. Importantly, C. gattii has a high prevalence in Latin America and has been proposed to be the likely origin of some C. gattii populations in North America. Thus, in the recent years, significant progress has been made with the study of the basic biology and laboratory identification of cryptococcal strains, in understanding their ecology, population genetics, host-pathogen interactions, and the clinical epidemiology of this important mycosis in Latin America.Fil: Firacative, Carolina. University of Sydney; AustraliaFil: Lizarazo, Jairo. Universidad de Pamplona; EspañaFil: Illnait Zaragozí, María Teresa. Tropical Medicine Institute Pedro Kourí; CubaFil: Castañeda, Maria Elizabeth. Instituto Nacional de Salud; Colombia. Latin American Cryptococcal Study Group; BrasilFil: Arechavala, Alicia. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Córdoba, Susana Beatríz. Latin American Cryptococcal Study Group; Brasil. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Mazza, Mariana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Taverna, Constanza Giselle. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Isla, Guillermina. Latin American Cryptococcal Study Group; Brasil. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Chiapello, Laura Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Vergara, Mario León Silva. Universidade Federal do Triangulo Mineiro; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Melhem, Marcia S. C.. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Szeszs, Maria Walderez. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Martins, Marilena dos Anjos. Latin American Cryptococcal Study Group; Brasil. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; BrasilFil: Bonfietti, Lucas Xavier. Latin American Cryptococcal Study Group; Brasil. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; BrasilFil: Oliveira, Rogério Antonio de. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Oliveira, Lidiane de. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Santos, Dayane Christine Silva. Latin American Cryptococcal Study Group; Brasil. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; BrasilFil: Lazera, Marcia S.. Latin American Cryptococcal Study Group; Brasil. Fundación Oswaldo Cruz; BrasilFil: Wanke, Bodo. Fundación Oswaldo Cruz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Díaz, María Cristina. Latin American Cryptococcal Study Group; Brasil. Universidad de Chile; ChileFil: Escandón, Patricia. Instituto Nacional de Salud; Colombia. Latin American Cryptococcal Study Group; BrasilFil: Noguera, María Clara. Latin American Cryptococcal Study Group; Brasil. Universidad Metropolitana; ColombiaFil: Andreu, Carlos Manuel Fernández. Latin American Cryptococcal Study Group; BrasilFil: Castril­Lón, Laura. Universidad Nacional Autónoma de México; México. Latin American Cryptococcal Study Group; BrasilFil: Bustamante, Beatriz. Hospital Cayetano Heredia. Instituto de Medicina Tropical Alexander von Humboldt; Perú. Hospital Cayetano Heredia; Perú. Latin American Cryptococcal Study Group; BrasilFil: Dolande, Maribel. Universidad Central de Venezuela; Venezuela. Latin American Cryptococcal Study Group; BrasilFil: Ferrara, Giussepe. Universidad Central de Venezuela; Venezuela. Latin American Cryptococcal Study Group; Brasi