355 research outputs found

    Influencia de diferentes modelos de Stent en la reestenosis de arterias coronarias = Influence of different coronary stent models in coronary artery restenosis

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    278 p.Los objetivos de este trabajo son determinar si los stents Apolo® con polímero P5® y paclitaxel a dosis de 0,17 µg/mm² (P5/T 0,5) y 0,32 µg/mm² (P5/T 1) son eficaces en la prevención de la reestenosis coronaria postratamiento. Como controles se utilizaron el stent Apolo® (BARE) y el stent Apolo® recubierto de polímero P5® (P5

    Neoformacion de minerales de la arcilla en la Espana Peninsular: tendencias termodinamicas basadas en la composicion de las aguas de los rios españoles

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    Stable or metastabie minerals are established for 381 sampling points from river water compositions for every spanish watershed aiong the years 1974-75, 1975-76, 1981-82, 1982-83 and 1983-84, as published by the spanish Department of Public Works. Phase diagrams for the systems SiO2-Al2O3-H2O, K2O-SiO2-Al2O3-H2O, Na2O-SiO2-Al2O3-H2O, MgO-SiO2-Al2O3-H2O, and CaO-SiO2-Al2O3-H2O, for 298 K and 1 atm. conditions, are used in order to determine the mineraiogical stability, and therefore neoformation trends. Stable and metastable phases were taken into account to draw the diagrams (Fernandez Marcos and Macias, 1987). The prevailing trend in the Peninsula, according to this method, is towards kaolinite neoformation. Nevertheless differences are observed between watersheds. So kaolinite is the only stable mineral neoformed in the North watersheds while there exist severa! stable minerals (kaolinite, mica, (kaolinite, mica, chlorite, pyrophillite) or metastable ones (smectite) in the Tajo, Guadiana, Guadalquivir, South, Jucar, Segura and East Pyrenees watersheds, depending on sampling point and date. Geographic distribution of different minerals is satisfactorily explained by taking into account: rainfall distribution, sileceous or calcareous nature of ground, and upper, medium or lower position in the river course

    A contribution to the study of the stability of clay minerals from the soil solution composition at different pF values

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    (EN)The composition of the soil solution of various horizons of Galician soils was studied to gain insight into the direction of the processes of weathering and neoformation by means of stability diagrams of the clay minerals. The soil solution was extracted by compression at various pF values. The most significant results are as follows: In all the cases studied the mineral in equilibrium with the soil solution is a 1:1 phyllosilicate. As the pF at which the soil solution is extracted increases, corresponding to smaller pore size, pH increases and silica concentration falls. The stable mineral does not vary significantly between different horizons of the same profile. Each parent material gives rise to a different zonation in the stability diagrams. The predictions of the stability diagrams are in general agreement with the mineralogical data of the clays of the horizons in question. Finally, weathering processes in Galicia are briefly commented on.(ES)Se realiza un estudio de la composición de la solución del suelo extraída por compresión a diferentes valores de pF como medio de conocer la dirección de los procesos de alteración y neoformación en diversos horizontes de suelos de Galicia, utilizando diagramas de estabilidad de los minerales de la arcilla. Los resultados más significativos son los siguientes: En todos los casos estudiados el mineral en equilibrio con la solución del suelo es un filosilicato 1:1. La solución extraída a valores crecientes de pF, que corresponden a tamaños de poros más pequeños, presenta valores de pH más altos y disminución de la concentración de sílice. No se aprecian diferencias significativas en cuanto al mineral estable en los diferentes horizontes de un mismo perfil. Para cada material original se aprecia una diferente zonaci6n en los diagramas de estabilidad. Las predicciones de los diagramas de estabilidad están generalmente de acuerdo con los datos mineralógicos de las arcillas de los horizontes correspondientes. Finalmente se realizan unas breves consideraciones sobre los procesos de alteración en Galicia

    Evaluation and validation of forest models: Insight from Mediterranean and scots pine models in Spain

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    Producción CientíficaForest models predict tree and stand evolution under different scenarios, thereby supporting decision-making in forest management. Models are complex structures composed of sub-models that estimate forest variables at tree and stand levels. Prediction accuracy has generally been evaluated independently of the model. Integrated sub-models make forest models easier to use and provide predictions for growth, survival, ingrowth and many other tree and stand variables with reduced effort. However, while individual submodel validation is widely practiced and normally done by each author individually, joint model validation remains less explored. This study deploys a useful methodology for evaluating and validating models. After comparing observed and predicted data, several case studies were then proposed to improve the accuracy of the joint model. We used the IBERO model, data from the Spanish National Forest Inventory and the SIMANFOR simulator platform. The accuracy of growth submodels was improved by calibrating their equations, though accuracy was not improved in survival and ingrowth submodels.FEDER - Junta de Castilla y León (CLU-2019-01 y CL-EI-2021-05)Project COMFOR-SUDOE: Integrated and intelligent management of complex forests and mixed-species plantations in Southwest Europe (SOE4/PA/E1012)Project SMART: Bosques mixtos : selvicultura, mitigación, adaptación, resiliencia y trade-offs (VA183P20)Project Integrated Forest Management along complexity gradients (IMFLEX) (PID2021-1262750B-C229

    Effectiveness and Efficiency of Drug Eluting Stents

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    Coronary artery disease (CAD), also known as ischemic heart disease (IHD) and coronary heart disease (CHD), is caused by the narrowing (stenosis) of one or more coronary arteries, due to atherosclerosis, restricting blood flow and reducing the supply of oxygen to the heart muscle. Transient shortages in blood flow and oxygen lead to angina pectoris and chest pain, which may radiate to the left shoulder, arms, neck, back or jaw. Stable angina symptoms do not tend to progress in intensity over time. More seriously, the rupturing of an atherosclerotic plaque (causing a thrombotic occlusion) and stenosis of the vessel can result in acute myocardial infarction (AMI) due to a critical reduction in the blood supply to the heart muscle (myocardial ischemia). High levels of morbidity and mortality associated with this infarction are a consequence of ischemia. It is vital to promptly re-establish coronary blood flow after an infarction, because sustained ischemic damages and injuries to the heart muscle may lead to sudden death or heart failure. In addition to infarction, acute symptomatic manifestations of ischemic heart disease include unstable angina, and less common conditions such as cardiogenic shock and sudden death (Thygesen, 2007)..

    Concepciones alternativas de los alumnos de Educación Secundaria sobre el enlace químico

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    En el presente trabajo se analizan las concepciones alternativas de los alumnos de 4º curso de Educación Secundaria Obligatoria (ESO) y 1º de Bachillerato sobre el enlace químico. Para ello se procedió a la administración de un cuestionario a 101 alumnos de ambos cursos. Los resultados muestran que, a pesar de que hay matices diferenciales entre ambos cursos, en los dos casos, los alumnos presentan dificultades para relacionar los niveles macro y micro de la química, y por tanto, para llegar a comprender y relacionar las propiedades macroscópicas de las sustancias con el tipo de unión que presentan las partículas (átomos, iones y moléculas) a nivel microscópicoIn this paper, the alternative misconceptions about chemical bond of 4th Compulsory Secondary Education and 1st of Bachillerato students are analyzed. The experimental work involved the administration of 101 questionnaires to students of both courses. The results show that, although there are differential nuances between both courses, the most important conclusion is that students have in common the difficulty to relate macro and micro levels of chemistry and, therefore, to reach the comprehension to relate the macroscopic properties of substances with the type of bonding that these particles (atoms, ions and molecules) have at the microscopic leve

    Effect of diet composition and ration size on key enzyme activities of glycolysis-gluconeogenesis, pentose phosphate pathway and amino acid metabolism in liver of Sparus aurata

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    The effects of diet composition and ration size on the activities of key enzymes involved in intermediary metabolism were studied in the liver of gilthead sea bream (Sparus aurata). Highcarbohydrate, low-protein diets stimulated 6-phosphofructo 1-kinase (EC 2.7.1.11), pyruvate kinase (EC 2.7.1.40), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44) enzyme activities, while they decreased alanine aminotransferase (EC 2.6.1.2) activity. A high degree of correlation was found between food ration size and the activity of the enzymes 6-phosphofructo 1-kinase, pyruvate kinase, glucose-6-phosphate dehydrogenase (positive correlations) and fructose-1,6-bisphosphatase (EC 3.1.3.11) (negative correlation). These correlations matched well with the high correlation also found between ration size and growth rate in starved fish refed for 22 d. Limited feeding (5 g/kg body weight) for 22 d decreased the activities of the key enzymes for glycolysis and lipogenesis, and alanine aminotransferase activity. The findings presented here indicate a high level of metabolic adaptation to both diet type and ration size. In particular, adaptation of enzyme activities to the consumption of a diet with a high carbohydrate level suggests that a carnivorous fish like Sparus aurata can tolerate partial replacement of protein by carbohydrate in the commercial diets supplied in culture. The relationship between enzyme activities, ration size and fish growth indicates that the enzymes quickly respond to dietary manipulations of cultured fish

    Percutaneous Treatment of Mitral and Tricuspid Regurgitation in Heart Failure

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    Heart failure has become a real epidemic condition related to poor outcomes despite advances in medical therapies. Prevalence of significant mitral and/or tricuspid regurgitation is high in patients with advanced heart failure. Novel transcatheter techniques have recently emerged as a minimally invasive alternative in patients deemed high-risk for surgery or inoperable. Among them, MitraClip® system is thus far the first device that received regulatory approval and gained widespread clinical application, especially in patients with functional mitral regurgitation. Furthermore, first experiences with new devices for percutaneous mitral and tricuspid valves repair, and transcatheter mitral valve prosthesis have been increasingly reported. Percutaneous therapies for valvular heart disease have therefore become one of the most promising fields in the present and future of interventional cardiology and heart failure

    Extension of the equilibration period up to 24 h maintains the post-thawing quality of Holstein bull semen frozen with OPTIXcell®

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    [EN] Semen cryopreservation in bovine livestock is well established, but logistics often require deviations from standard protocols. Extending the equilibration time to the following day is convenient in many situations. To improve our knowledge of the effects of this modification, we studied the post-thawing and post-incubation (4 h, 38 °C) sperm quality after freezing with 4 or 24-h extension in the OPTIXcell extender by using an ample panel of analyses: CASA for motility; flow cytometry for viability, physiology, oxidative stress, and chromatin parameters (DNA fragmentation, chromatin compaction, and thiol groups status); and spectrometry for malondialdehyde production. Semen was obtained from 12 Holstein bulls. The 24-h equilibration time showed few significant effects, with only a tiny decrease in progressive motility and a positive impact on chromatin structure. The incubation removed some of these effects, with the pattern for chromatin compaction remaining the same. No detrimental oxidative stress or increase in apoptotic or capacitation markers was detected. Additionally, the individual bull interacted with the effects of the incubation and the equilibration, especially regarding the chromatin status. Whereas this interaction did not critically affect sperm quality, it could be relevant in practice. Bull fertility as non-return rates (NRR56) was associated with some sperm parameters (especially with an improved chromatin structure) but not in the 4-h post-thawing analysis. Our study supports that extending the equilibration time by at least 24-h is feasible for bull semen freezing with the OPTIXcell extender.S

    Alanine aminotransferase: A target to improve utilisation of dietary nutrients in aquaculture

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    Podeu consultar el llibre complet a: http://hdl.handle.net/2445/67430Alanine aminotransferase (ALT) is a sensitive marker of dietary protein utilisation in fish. Three ALT isoforms (cALT1, cALT2 and mALT) encoded by two genes have been isolated from gilthead sea bream (Sparus aurata). Molecular characterization of ALT isozymes and gene promoters suggest involvement of cALT1 and mALT in postprandial use of dietary amino acids, while cALT2 seems associated to hepatic gluconeogenesis. Inhibition of hepatic cytosolic ALT activity stimulates pyruvate kinase and decreases the renewal rate of alanine in S. aurata. These findings point to ALT as a target to spare protein and improve catabolism of dietary carbohydrates in cultured fish
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