Investigaciones y estudios sobre revoques simil piedra

En los últimos años se vienen realizando tareas de reparación, reciclaje y restauración en edificios y construcciones, muchos de los cuales son importantes monumentos, siendo algunos de ellos considerados los edificios mas valiosos del patrimonio arquitectónico del país. No obstante en muchos de los casos los proyectos están por debajo de los niveles técnicos, lógicos y serios que se deberían considerar al efectuar estas intervenciones. En este trabajo se pretende aportar al desarrollo de investigaciones y técnicas de laboratorio que permitirían encarar estos emprendimientos con base científica al suplantar revoques o revestimientos originales y alterados por patologías por materiales y técnicas actuales. Se consideran las determinaciones clásicas de análisis físico, químico y petrográfico de los materiales intervinientes y se presentan algunas técnicas sencillas para relacionar la porosidad y permeabilidad de los revestimientos y su velocidad de deterioro principalmente las vinculadas con las alteraciones visuales. Además, se comentan resultados preliminares del análisis de microfotografías de revestimientos simil piedra tomadas en edificios actualmente en proceso de restauración con las formulaciones propuestas para el reemplazo. Con los datos obtenidos podemos orientar fuertemente que tipo de mortero puede ser más adecuado para sustituir revestimientos alterados por el agua en edificios históricos

A covalent organic/inorganic hybrid proton exchange polymeric membrane: synthesis and characterization

Commercial polyetheretherketone (Victrex PEEK) was sulfonated up to 90% degree of sulfonation (DS), then reacted with SiCl4 to obtain a hybrid polymer. The product was characterized by 29-Si NMR and ATR/FTIR spectroscopies demonstrating the formation of covalent bonds between the organic and inorganic components. No dispersed inorganic silicon was present in the product as evidenced by the lack of any resonance at 100 ppm. Despite the high DS the physicochemical properties of the hybrid were suitable for the preparation of membranes exhibiting high and stable conductivity values (10K2 S/cm), hence suitable for application as ion exchange membrane

Probing the bulk ionic conductivity by thin film hetero-epitaxial engineering

Highly textured thin films with small grain boundary regions can be used as model systems to directly measure the bulk conductivity of oxygen ion conducting oxides. Ionic conducting thin films and epitaxial heterostructures are also widely used to probe the effect of strain on the oxygen ion migration in oxide materials. For the purpose of these investigations a good lattice matching between the film and the substrate is required to promote the ordered film growth. Moreover, the substrate should be a good electrical insulator at high temperature to allow a reliable electrical characterization of the deposited film. Here we report the fabrication of an epitaxial heterostructure made with a double buffer layer of BaZrO3 and SrTiO3 grown on MgO substrates that fulfills both requirements. Based on such template platform, highly ordered (001) epitaxially oriented thin films of 15% Sm-doped CeO2 and 8 mol% Y2O3 stabilized ZrO2 are grown. Bulk conductivities as well as activation energies are measured for both materials, confirming the success of the approach. The reported insulating template platform promises potential application also for the electrical characterization of other novel electrolyte materials that still need a thorough understanding of their ionic conductivity. © 2015 National Institute for Materials Science

Estudio e investigaciones realizadas en el LEMIT sobre materiales empleados en edificios históricos

Cuando se abordan problemas de restauración, reparación y conservación de edificios y construcciones de valor histórico se debe realizar, antes de iniciar las tareas de puesta en valor, un estudio integral de las causales que han provocado los deterioros. Esta situación es de primordial importancia, ya que si no se eliminan las causales, rápidamente reaparecen los signos externos de las alteraciones. Sin embargo, muchas de las alteraciones y/o deterioros de las construcciones de valor patrimonial y/o de los materiales que las constituyen se deben, con exclusividad, al pasaje del tiempo (vida en servicio de la construcción). Los materiales empleados en la construcción experimentan procesos de deterioro por reacciones físico, químicas o físico-químicas entre el material y los agentes agresivos o el originado por el crecimiento de microorganismos, en particular algas en sectores húmedos y sombríos y/o líquenes o plantas mayores como por ejemplo helechos. En este trabajo se presentan investigaciones y estudios de distintos materiales constituyentes de construcciones de valor patrimonial, en particular, se analizan ladrillos cerámicos comunes, mezclas de asiento, morteros internos y externos, tejas y materiales de revestimiento (cerámicos, pinturas y papel). Estos estudios fueron realizados para la caracterización de los materiales y/o para disponer de información técnica para su restauración o reemplazo. En todos los casos, se informan las técnicas de caracterización mecánica, física y química empleadas para su evaluación. En algunos casos, se realizan estudios de difracción de rayos X, microscopia electrónica de barrido (SEM), cortes petrográficos, análisis en lupa microscópica y microscopio petrográfico. Además, se han aplicado técnicas para determinar color y rugosidad

Mapping Cell Identity from scRNA-seq: A primer on computational methods

Single cell (sc) technologies mark a conceptual and methodological breakthrough in our way to study cells, the base units of life. Thanks to these technological developments, large-scale initiatives are currently ongoing aimed at mapping of all the cell types in the human body, with the ambitious aim to gain a cell-level resolution of physiological development and disease. Since its broad applicability and ease of interpretation scRNA-seq is probably the most common sc-based application. This assay uses high throughput RNA sequencing to capture gene expression profiles at the sc-level. Subsequently, under the assumption that differences in transcriptional programs correspond to distinct cellular identities, ad-hoc computational methods are used to infer cell types from gene expression patterns. A wide array of computational methods were developed for this task. However, depending on the underlying algorithmic approach and associated computational requirements, each method might have a specific range of application, with implications that are not always clear to the end user. Here we will provide a concise overview on state-of-the-art computational methods for cell identity annotation in scRNA-seq, tailored for new users and non-computational scientists. To this end, we classify existing tools in five main categories, and discuss their key strengths, limitations and range of application

Hippo pathway effectors control cardiac progenitor cell fate by acting as dynamic sensors of substrate mechanics and nanostructure

Stem cell responsiveness to extracellular matrix (ECM) composition and mechanical cues has been the subject of a number of investigations so far, yet the molecular mechanisms underlying stem cell mechano-biology still need full clarification. Here we demonstrate that the paralog proteins YAP and TAZ exert a crucial role in adult cardiac progenitor cell mechano-sensing and fate decision. Cardiac progenitors respond to dynamic modifications in substrate rigidity and nanopattern by promptly changing YAP/TAZ intracellular localization. We identify a novel activity of YAP and TAZ in the regulation of tubulogenesis in 3D environments and highlight a role for YAP/TAZ in cardiac progenitor proliferation and differentiation. Furthermore, we show that YAP/TAZ expression is triggered in the heart cells located at the infarct border zone. Our results suggest a fundamental role for the YAP/TAZ axis in the response of resident progenitor cells to the modifications in microenvironment nanostructure and mechanics, thereby contributing to the maintenance of myocardial homeostasis in the adult heart. These proteins are indicated as potential targets to control cardiac progenitor cell fate by materials design

Angiostrongylosis-related restrictive pneumopathy assessed by arterial blood gas analysis in a dog

Pulmonary angiostrongylosis was diagnosed by the Baermann method and larval identification from faecal and bronchoalveolar lavage samples in a five-month- old male mongrel dog with dyspnoea and cough. Arterial blood gas analysis indicated arterial hypoxaemia and restrictive pneumopathy. In addition to the palliative treatment, fenbendazole was administered (50 mg/kg/24 h per os) for 14 days. The respiratory signs subsided within a short time clinically, but serial arterial blood gas analysis demonstrated an ongoing ventilation disorder. Repeated haematology, thoracic radiography, bronchoscopy and blood gas analysis were performed to follow the course of the disease. The most severe eosinophilia was detected after the beginning of the anthelmintic therapy, and the arterial pO2 level was permanently low. Arterial blood gas analysis provided the most adequate information about the course of the pneumopathy and it greatly facilitated the patient’s medical management

Preliminary results from antarctic albedo from remote sensing observations

The aim of the study is to analyse the surface albedo of the Ant-arctica and investigate eventual signals of variations in space and time between summer 2000/2001 and 2011/2012 by means of the GLASS albedo product. We followed a step-by-step procedure from micro- to macro-scale. At first, we analysed 95 glaciers around the continent, and we found limited temporal variability. Then, looking at spatial varia-tions, we divided Antarctica based on oceanic basins and by continen-tality. We found spatial signals, since mean albedo values range between 0.79 (Pacific and Atlantic basins) and 0.82 (Indian basin) and between 0.76 (along the shore) and 0.81 (inner continent). An increasing vari-ability was found from the inner continent to the shore, and heteroge-neous patterns among the basins, most likely due to meteorological and environmental conditions (mainly: temperature, precipitation, katabatic winds). Finally, the general patterns observed (considering the specific gla-ciers, the three basins and the three continentality sectors) were verified by the analysis of the whole continent and we did not find a significant change of summer averages over time, as they range between 0.79 and 0.80