The influence of fly ash as substitute of cement in the durability of concrete

Limitation of transport capacity through the concrete is one of the key points in the improvement of the material’s durability. The use of fly ash as an admixture to concrete is widely extended; a general consensus has been established due to the pore size reduction produced by the ashes. Nevertheless, the importance of the micro-structural and composition changes in mechanical and durable properties is not well defined. In the present study the use of fly ash has been considered as substitute of cement in the design limits. The concrete mechanical properties and its porous structure were evaluated. The tests included porosimetry and water permeability tests. In order to characterize the hydration products and its evolution with time TG and DTA analysis were performed. This work studies the fly ash concrete hydration process, their influence in the porous distribution, and the mechanical and durable properties of the material

Redes bayesianas para identificar perfiles de estudiante. Aplicación al estudio del abandono de las titulaciones de Informática en la Universidad de Castilla-La Mancha

El abandono de los estudiantes es un problema que afecta a todas las universidades siendo más acusado en las titulaciones de las ramas de Ingeniería y Arquitectura. Como docentes del Grado de Ingeniería Informática de la Universidad de Castilla-La Mancha nuestro interés se centra en analizar el perfil del estudiante que abandona estos estudios, con el fin de definir acciones orientadas a reducir la actual tasa de abandono. En ediciones anteriores de las JENUI se ha analizado esta problemática desde el punto de vista de la estadística tradicional y de la minería de datos, mediante árboles de decisión y regresión multivariante; en este trabajo lo abordamos mediante algoritmos de aprendizaje de redes bayesianas, ya que éstas tienen una semántica muy rica y son fácilmente interpretables. Los resultados del trabajo no son concluyentes debido a las restricciones de la base de datos utilizada, pero la descripción del estudio realizado pone en valor el interés de la técnica empleada y sienta las bases para mejorar el alcance de la investigación en trabajos futuros relacionados con la extración de datos de futuros estudiantes

Procjena utjecaja disruptora bisfenola A na ionske regulacije kod Danio rerio kroz ispitivanje njihovih kloridnih i prolaktinskih stanica

Bisphenol A (BPA) is one of the chemicals produced in the largest volume in the world. It is commonly used as a component of plastics and food containers and can act as a xenoestrogen in humans. In view of the risk of exposure to it from the environment and diet, and basically as a water pollutant, the objective of our study was to assess possible effects on ionic regulation after exposure to BPA by means of a histopathological and morphometric study of the chloride and prolactin cells in zebrafish (Danio rerio) as an experimental model. Twenty-five male 16-week old zebrafish (Danio rerio) were allocated randomly into 5 study groups (n=5/group); a control group, and four groups, exposed for 2 weeks to a concentration of (1, 10, 100 and 1000 μg/L) of BPA, respectively. After 2 weeks, the animals were sacrificed and samples of their gills and pituitary gland were immediately taken for their subsequent histopathological analysis. Our results showed how, in the first study groups, lesions appeared in chloride cells, generating compensatory modifications in the prolactin cells, which were enough to maintain stability in the ionic exchange. As the exposure concentration increased, more serious histological modifications occurred. In the groups with the highest concentration (100 and 1000 μg/L), the lesions were so severe that the prolactin cells underwent some degenerative processes, which probably prevented the compensatory action at gill level.Bisfenol A je jedan od kemijskih spojeva koji se najviše proizvodi u svijetu. Najčešće se koristi za dobivanje plastike i posuda za hranu i može djelovati kao ksenoestrogen kod ljudi. S obzirom na rizik izloženosti bisfenolu A iz okoline i prehrane, i u osnovi kao zagađivaču vode. Cilj istraživanja bio je procijeniti moguće učinke na ionsku regulaciju nakon izlaganja bisfenolu A pomoću histopatološke i morfometrijske studije kloridnih i prolaktinskih stanica u Danio rerio kao eksperimentalnog modela. Dvadesetpet muških jedinki 16 tjedana starih Danio rerio bili su nasumično raspoređeni u pet ispitivanih skupina (n=5/skupina). Kontrolna skupina i četiri skupine bile su dva tjedna izložene koncentracijama od 1, 10, 100 odnosno 1000 μg/L bisfenola A. Nakon ta dva tjedna uzorci njihovih škrga i hipofize su odmah izuzeti za naknadnu patohistološku analizu. Rezultati su pokazali kako su se, kod prvih ispitivanih skupina, lezije pojavile u kloridnim stanicama, stvarajući kompenzacijske promjene na prolaktinskim stanicama koje su bile dovoljne za održavanje stabilnosti u izmjeni iona. Kako se povećavala koncentracija izloženosti, ozbiljnije histološke modifikacije su se dogodile. Kod skupina s višom koncentracijom (100 i 1000 μg/L) lezije su bile tako jake da su prolaktinske stanice prošle kroz određene degenerativne procese, što je vjerojatno spriječilo kompenzacijsko djelovanje na škrgama

Influence of cement properties in the reaction rate and mechanical behavior of concrete with high fl y ash content

The use of fly ash (FA) as an admixture to concrete is broadly extended for two main reasons: the reduction of costs that supposes the substitution of cement and the micro structural changes motivated by the mineral admixture. Regarding this second point, there is a consensus that considers that the ash generates a more compact concrete and a reduction in the size of the pore. However, the measure in which this contributes to the pozzolanic activity or as filler is not well defined. There is also no justification to the influence of the physical parameters, fineness of the grain and free water, in its behavior. This work studies the use of FA as a partial substitute of the cement in concretes of different workability (dry and wet) and the influence in the reactivity of the ash. The concrete of dry consistency which serves as reference uses a cement dose of 250 Kg/m 3 and the concrete of fluid consistency utilized a dose of cement of 350 Kg/m 3 . Two trademark of Portland Cement Type 1 were used. The first reached the resistant class for its fineness of grain and the second one for its composition. Moreover, three doses of FA have been used, and the water/binder ratio was constant in all the mixtures. We have studied the mechanical properties and the micro-structure of the concretes by means of compressive strength tests, mercury intrusion porosimetry (MIP) and thermal analysis (TA). The results of compressive strength tests allow us to observe that concrete mixtures with cements of the same classification and similar dosage of binder do not present the same mechanical behavior. These results show that the effective water/binder ratio has a major role in the development of the mechanical properties of concrete. The study of different dosages using TA, thermo-gravimetry and differential thermal analysis, revealed that the portlandite content is not restrictive in any of the dosages studied. Again, this proves that the rheology of the material influences the reaction rate and content of hydrated cement products. We conclude that the available free water is determinant in the efficiency of pozzolanic reaction. It is so that in accordance to the availability of free water, the ashes can react as an active admixture or simply change the porous distribution. The MIP shows concretes that do not exhibit significant changes in their mechanical behavior, but have suffered significant variation in their porous structur

Increased AGE-RAGE ratio in idiopathic pulmonary fibrosis

Background: the abnormal epithelial-mesenchymal restorative capacity in idiopathic pulmonary fibrosis (IPF) has been recently associated with an accelerated aging process as a key point for the altered wound healing. The advanced glycation end-products (AGEs) are the consequence of non-enzymatic reactions between lipid and protein with several oxidants in the aging process. The receptor for AGEs (RAGEs) has been implicated in the lung fibrotic process and the alveolar homeostasis. However, this AGE-RAGE aging pathway has been under-explored in IPF. Methods: lung samples from 16 IPF and 9 control patients were obtained through surgical lung biopsy. Differences in AGEs and RAGE expression between both groups were evaluated by RT-PCR, Western blot and immunohistochemistry. The effect of AGEs on cell viability of primary lung fibrotic fibroblasts and alveolar epithelial cells was assessed. Cell transformation of fibrotic fibroblasts cultured into glycated matrices was evaluated in different experimental conditions. Results: our study demonstrates an increase of AGEs together with a decrease of RAGEs in IPF lungs, compared with control samples. Two specific AGEs involved in aging, pentosidine and Nε-Carboxymethyl lysine, were significantly increased in IPF samples. The immunohistochemistry identified higher staining of AGEs related to extracellular matrix (ECM) proteins and the apical surface of the alveolar epithelial cells (AECs) surrounding fibroblast foci in fibrotic lungs. On the other hand, RAGE location was present at the cell membrane of AECs in control lungs, while it was almost missing in pulmonary fibrotic tissue. In addition, in vitro cultures showed that the effect of AGEs on cell viability was different for AECs and fibrotic fibroblasts. AGEs decreased cell viability in AECs, even at low concentration, while fibroblast viability was less affected. Furthermore, fibroblast to myofibroblast transformation could be enhanced by ECM glycation. Conclusions: all of these findings suggest a possible role of the increased ratio AGEs-RAGEs in IPF, which could be a relevant accelerating aging tissue reaction in the abnormal wound healing of the lung fibrotic process

Anti-fibrotic Effects Of Pirfenidone And Rapamycin In Primary Ipf Fibroblasts And Human Alveolar Epithelial Cells

Background: Pirfenidone, a pleiotropic anti-fibrotic treatment, has been shown to slow down disease progression of idiopathic pulmonary fibrosis (IPF), a fatal and devastating lung disease. Rapamycin, an inhibitor of fibroblast proliferation could be a potential anti-fibrotic drug to improve the effects of pirfenidone. Methods: Primary lung fibroblasts from IPF patients and human alveolar epithelial cells (A549) were treated in vitro with pirfenidone and rapamycin in the presence or absence of transforming growth factor beta 1 (TGF-beta). Extracellular matrix protein and gene expression of markers involved in lung fibrosis (tenascin-c, fibronectin, collagen I (COM Al], collagen III [COL3A1] and alpha-smooth muscle actin [alpha-SMA]) were analyzed. A cell migration assay in pirfenidone, rapamycin and TGF-beta-containing media was performed. Results: Gene and protein expression of tenascin-c and fibronectin of fibrotic fibroblasts were reduced by pirfenidone or rapamycin treatment Pirfenidone-rapamycin treatment did not revert the epithelial to mesenchymal transition pathway activated by TGF-beta. However, the drug combination significantly abrogated fibroblast to myofibroblast transition. The inhibitory effect of pirfenidone on fibroblast migration in the scratch-wound assay was potentiated by rapamycin combination. Conclusions: These findings indicate that the combination of pirfenidone and rapamycin widen the inhibition range of fibrogenic markers and prevents fibroblast migration. These results would open a new line of research for an anti-fibrotic combination therapeutic approach

Deep learning for coronary artery disease severity classification

Medical imaging evaluations are one of the fields where computed-aid diagnosis could improve the efficiency of diagnosis supporting physician decisions. Cardiovascular Artery Disease (CAD) is diagnosed using the gold standard, Invasive Coronary Angiography (ICA). In this work, performance analysis for binary classification of ICA images considering the severity ranges separately is reported, evaluating how performance is affected depending on the degree of lesions considered. For this purpose, an annotated dataset of ICA images was employed, which contains the ground truth, the location and the category of lesions into seven possible ranges: <20 %, [20 %, 49 %], [50 %, 69 %], [70 %, 89 %], [90 %, 98 %], 99 %, and 100 %. The ICA images were pre-processed, divided into patches and balanced by downsampling and data augmentation. In this study, four known pre-trained CNN architectures were trained using different categories of lesion degree as input, whose F-measures are computed. Results report that the F-measures showed a behavior dependent on the narrow presents of the image, being lesions with more than 50 % severity were better classified, achieving an F-measure of 75%.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Evaluación de una innovación docente a través de un diseño estadístico cuasi-experimental: aplicación al aprendizaje de la recursividad

Una de las principales dificultades que tienen que superar los alumnos que empiezan a programar es el aprendizaje de la recursividad. Nuestro interés se centra en conocer las causas que están detrás de esta problemática e intentar solventarla. Creemos que uno de los principales motivos que podrían explicar este fenómeno es el enorme desajuste conceptual que les supone el cambio de paradigma, de imperativo a declarativo. Con el objetivo de testear qué enfoque es el más apropiado a la hora de enseñar la recursividad en asignaturas de primeros cursos de Programación, se han diseñado dos estudios empíricos. En este trabajo describimos en detalle cada uno de ellos, así como los resultados obtenidos y las lecciones aprendidas.One of the main difficulties that students who start learning programming have to overcome is recursion. Our interest is to know the causes behind this problem and try to resolve it. We believe that one of the main reasons that could explain this phenomenon is the enormous conceptual mismatch that they incur when shifting from imperative to declarative paradigm. In order to test which approach is the most appropriate when teaching recursion in subjects of early programming courses we have designed two empirical studies. In this paper we describe in detail each of them, as well as the results and lessons learned