Espectroscopia infrarroja

Los métodos espectroscópicos de análisis tienen un amplio uso en el estudio de obras de valor patrimonial, tanto en materiales orgánicos como inorgánicos. En el caso particular de la espectroscopia infrarroja, una de las mayores dificultades en el proceso de identificación de compuestos de carácter orgánico se encuentra asociada al envejecimiento de los materiales originales. Este proceso comprende una alteración de la estructura química y, consecuentemente, la modificación de los espectros infrarrojos. La mayoría de las técnicas espectroscópicas empleadas para la identificación y cuantificación de materiales se basan en la comparación contra espectros de referencia, que generalmente, pertenecen a materiales nuevos, lo cual dificulta el análisis de muestras reales envejecidas. Este trabajo muestra, a partir de un banco de datos de materiales envejecidos artificialmente, que los espectros de éstos pueden modificarse drásticamente en el tiempo y que estas modificaciones dependen de la naturaleza del material analizado. Asimismo, se exponen ejemplos de muestras reales cuyos espectros se ajustan adecuadamente a los de las muestras envejecidas artificialmente y en donde una comparación contra patrones nuevos impediría su identificación e inclusive podría llevar a falsas conclusiones.Tópico 4: Materiales. Evaluación de propiedades, caracterización tecnológica y patologías. Mamposterías (de ladrillos o piedras) y Morteros (materiales cálcicos y cementícios)

Modeling Molecular Interactions in Water: From Pairwise to Many-Body Potential Energy Functions.

Almost 50 years have passed from the first computer simulations of water, and a large number of molecular models have been proposed since then to elucidate the unique behavior of water across different phases. In this article, we review the recent progress in the development of analytical potential energy functions that aim at correctly representing many-body effects. Starting from the many-body expansion of the interaction energy, specific focus is on different classes of potential energy functions built upon a hierarchy of approximations and on their ability to accurately reproduce reference data obtained from state-of-the-art electronic structure calculations and experimental measurements. We show that most recent potential energy functions, which include explicit short-range representations of two-body and three-body effects along with a physically correct description of many-body effects at all distances, predict the properties of water from the gas to the condensed phase with unprecedented accuracy, thus opening the door to the long-sought "universal model" capable of describing the behavior of water under different conditions and in different environments

Re-emergence of enterovirus d68 in europe after easing the covid-19 lockdown, september 2021

We report a rapid increase in enterovirus D68 (EVD68) infections, with 139 cases reported from eight European countries between 31 July and 14 October 2021. This upsurge is in line with the seasonality of EV-D68 and was presumably stimulated by the widespread reopening after COVID-19 lockdown. Most cases were identified in September, but more are to be expected in the coming months. Reinforcement of clinical awareness, diagnostic capacities and surveillance of EV-D68 is urgently needed in Europe

Epidemiological and clinical insights into the enterovirus D68 upsurge in Europe 2021/22 and the emergence of novel B3-derived lineages, ENPEN multicentre study

International audienceEnterovirus D68 (EV-D68) infections are associated with severe respiratory disease and acute flaccid myelitis (AFM). The European Non-Polio Enterovirus Network (ENPEN) aimed to investigate the epidemiological and genetic characteristics of EV-D68 and its clinical impact during the fall-winter season of 2021/22. From 19 European countries, 58 institutes reported 10,481 (6.8%) EV-positive samples of which 1,004 (9.6%) were identified as EV-D68 (852 respiratory samples). Clinical data was reported for 969 cases. 78.9% of infections were reported in children (0-5 years); 37.9% of cases were hospitalised. Acute respiratory distress was commonly noted (93.1%) followed by fever (49.4%). Neurological problems were observed in 6.4% of cases with six reported with AFM. Phylodynamic/Nextstrain and phylogenetic analyses based on 694 sequences showed the emergence of two novel B3-derived lineages, with no regional clustering. In conclusion, we describe a large-scale EV-D68 European upsurge with severe clinical impact and the emergence of B3-derived lineages