2,698 research outputs found

    Dissipative solitons which cannot be trapped

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    In this paper we study the behavior of dissipative solitons in systems with high order nonlinear dissipation and show how they cannot survive under the effect of trapping potentials both of rigid wall type or asymptotically increasing ones. This provides an striking example of a soliton which cannot be trapped and only survives to the action of a weak potential

    CAR T cells for T-cell leukemias: Insights from mathematical models

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    Immunotherapy has the potential to change the way all cancer types are treated and cured. Cancer immunotherapies use elements of the patient immune system to attack tumor cells. One of the most successful types of immunotherapy is CAR-T cells. This treatment works by extracting patient's T-cells and adding to them an antigen receptor allowing tumor cells to be recognized and targeted. These new cells are called CAR-T cells and are re-infused back into the patient after expansion in-vitro. This approach has been successfully used to treat B-cell malignancies (B-cell leukemias and lymphomas). However, its application to the treatment of T-cell leukemias faces several problems. One of these is fratricide, since the CAR-T cells target both tumor and other CAR-T cells. This leads to nonlinear dynamical phenomena amenable to mathematical modeling. In this paper we construct a mathematical model describing the competition of CAR-T, tumor and normal T-cells and studied some basic properties of the model and its practical implications. Specifically, we found that the model reproduced the observed difficulties for in-vitro expansion of the therapeutic cells found in the laboratory. The mathematical model predicted that CAR-T cell expansion in the patient would be possible due to the initial presence of a large number of targets. We also show that, in the context of our mathematical approach, CAR-T cells could control tumor growth but not eradicate the disease

    Gene flow and genetic structure in the Galician population (NW Spain) according to Alu insertions

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    <p>Abstract</p> <p>Background</p> <p>The most recent <it>Alu </it>insertions reveal different degrees of polymorphism in human populations, and a series of characteristics that make them particularly suitable genetic markers for Human Biology studies. This has led these polymorphisms to be used to analyse the origin and phylogenetic relationships between contemporary human groups. This study analyses twelve <it>Alu </it>sequences in a sample of 216 individuals from the autochthonous population of Galicia (NW Spain), with the aim of studying their genetic structure and phylogenetic position with respect to the populations of Western and Central Europe and North Africa, research that is of special interest in revealing European population dynamics, given the peculiarities of the Galician population due to its geographical situation in western Europe, and its historical vicissitudes.</p> <p>Results</p> <p>The insertion frequencies of eleven of the <it>Alu </it>elements analysed were within the variability range of European populations, while Yb8NBC125 proved to be the lowest so far recorded to date in Europe.</p> <p>Taking the twelve polymorphisms into account, the GD value for the Galician population was 0.268. The comparative analyses carried out using the MDS, NJ and AMOVA methods reveal the existence of spatial heterogeneity, and identify three population groups that correspond to the geographic areas of Western-Central Europe, Eastern Mediterranean Europe and North Africa. Galicia is shown to be included in the Western-Central European cluster, together with other Spanish populations. When only considering populations from Mediterranean Europe, the Galician population revealed a degree of genetic flow similar to that of the majority of the populations from this geographic area.</p> <p>Conclusion</p> <p>The results of this study reveal that the Galician population, despite its geographic situation in the western edge of the European continent, occupies an intermediate position in relation to other European populations in general, and Iberian populations in particular. This confirms the important role that migratory movements have had in the European gene pool, at least since Neolithic times. In turn, the MDS and NJ analyses place Galicia within the group comprised of Western-Central European populations, which is justified by the influence of Germanic peoples on the Galician population during the Middle Ages. However, it should also be noted that some of the markers analysed have a certain degree of differentiation, possibly due to the region's position as a 'cul-de-sac' in terms of Iberian population dynamics.</p

    Application of the Rietveld Method to Quantify Mineral Phases in a Kaolin Mineral

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    The applications of the mineral kaolin are varied, such as the ceramic industry, and the pharmaceutical industry, among others; although it is generally found in mining deposits accompanied by other mineral species considered contaminants. The above makes it necessary to apply qualitative and quantitative analysis techniques that determine the purity of the mineral, from its extraction, during its mechanical processing and kaolin recovery. In this work, a procedure for quantification of the majority species in the Kaolin mineral is proposed, according to the procedure proposed by Rietveld, from the diffractogram obtained by the x-ray diffraction technique, as well as the knowledge of the crystallographic characteristics of the mineral constituents. Three models are proposed based on the structural parameters of the phases present in the system: tridymite, cristobalite, and kaolinite. The experimental results show the total adjustment of the diffraction pattern in which it is observed that the weight percentage corresponds to 40.0% for tridymite, 39.5% for cristobalite, and 20.5% for kaolinite. These results were corroborated by specific semi-quantitative chemical analyses using scanning electron microscopy.&nbsp

    Diel-depth distributions of fish larvae off the Balearic Islands (western Mediterranean) under two environmental scenarios

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    Final workshop IDEADOS: The wrapping up of the IDEADOS project, International Workshop on Environment, Ecosystems and Demersal Resources and fisheries, 14-16 November 2012, Palma de Mallorca, SpainPeer reviewe

    Physiological response of post-veraison deficit irrigation strategies and growth patterns of table grapes (cv. Crimson Seedless)

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    To determine whether partial root-zone drying (PRD) offers physiological advantages compared with regulated deficit irrigation (RDI), a 3 year long-experiment was conducted on a commercial vineyard of ‘Crimson Seedless’ table grapes (Vitis vinifera L.). Four different drip irrigation treatments were imposed: (i) a Control treatment irrigated at 110% of seasonal crop evapotranspiration (ETc), (ii), a regulated deficit irrigation (RDI) treatment irrigated similar to Control before veraison and at 50% of the Control treatment post-veraison, (iii) a partial root-zone drying (PRD) irrigated similar to RDI but alternating (every 10–14 days) the dry and wet side of the root-zone, and (iv) a null irrigation treatment (NI) which only received the natural precipitation and occasional supplementary irrigation when midday stem water potential (Ψs) dropped below −1.2 MPa. Post-veraison, PRD vines accumulated greater localized soil and plant water deficit at midday than RDI vines, but maintained similar pre-dawn water potential (Ψpd) values. Stomatal conductance (gs) of PRD vines remained high, likely because there was sufficient root water uptake from irrigated soil. Xylem ABA concentration ([ABA]xylem) did not change yet intrinsic WUE (WUEi) decreased compared to RDI vines, probably because PRD induced greater root density and root development at depth, allowing greater water uptake from roots in the wet part of the soil profile. Vegetative growth was only decreased by severe deficit irrigation (NI) although total leaf area index (LAI) was also affected by PRD in the 1st and 3rd year.. PRD can be considered a useful strategy in semiarid areas with limited water resources because sustained water use maintained assimilation rates despite greater stress than conventional RDI strategy, which may be related to root and morphological adjustment

    Estudio descriptivo de los hábitos alimenticios y del consumo de alcohol en una muestra de estudiantes de la Universidad de Alicante

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    Objetivo. Describir la frecuencia de consumo de determinados alimentos y bebidas alcohólicas en una muestra de estudiantes de la Universidad de Alicante. Material y métodos. El instrumento utilizado para la recogida de datos fue un cuestionario de frecuencias de consumo, aplicado mediante entrevista personal a una muestra accidental de 1250 personas, (692 mujeres y 488 hombres), con un rango de edad de 17-40 años. Constaba de cuatro secciones: 1ª) número de comidas y lugar donde se realizan; 2ª) patrones de consumo de los distintos grupos de alimentos; 3ª) patrones de consumo de bebidas alcohólicas, diferenciando lo bebido de lunes a jueves y de viernes a domingo; y 4ª) datos de identificación y demográficos. Resultados. Los datos obtenidos coinciden con los expuestos por otros autores, y muestran que nuestro modelo alimentario se caracteriza por un alto consumo de carnes (=4 veces/semana), adecuada ingesta de huevos (=2,5 v/sem.) e hidratos de carbono complejos (arroz y pastas =4,2 v/sem.), consumo ligeramente inferior al recomendado de frutas (=5,3 v/sem.) e insuficiente de legumbres (=2,2 v:/sem.), verduras y hortalizas frescas (=3,9 v/sem.), y pescados (=2 v/sem.). El consumo de bebidas alcohólicas fue: 2,6 vasos/semana de cerveza, 2,1 v/sem. de combinados, 1,2 v/sem. de licores y 0,8 v/sem. de vino. Los porcentajes de consumidores fueron para la cerveza del 51,1 %, para los combinados del 61,4%, para los licores del 40,9%, y para el vino 18,7%. Los datos señalan que los hombres consumen más bebidas alcohólicas que las mujeres (t=7,79 p<0,001) y que quienes empiezan antes a consumirlas son quienes en mayor cantidad lo hacen (t=-3,17 p<0,001). Conclusiones. Pese a la diferencia existente entre medias de edad y nivel cultural, existe una similitud entre los datos obtenidos en este estudio y el realizado sobre la población de la ciudad de Alicante. Las encuestas alimentarias y de consumo de alcohol realizadas en España son escasas y con diversa metodología, lo que dificulta la comparación de los resultados obtenidos con otros estudios previos

    Type of grinding of the main cereal of the diet affects production of brown egg-laying hens

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    The influence of method of grinding of the cereal of the diet on production and egg quality was studied in 420 Hy-line brown egg-laying hens. The design was completely randomized with six treatments arranged as a 3 × 2 factorial with three cereals (barley, dented maize and soft wheat) and two grinding procedures (hammer mill vs. roller mill). Each treatment was replicated seven times and the experimental unit was an enriched cage with ten hens. Production was recorded every four weeks from 24 to 59 weeks of age and egg quality was measured at 40 and 56 weeks of age. For the entire experiment, feed intake was higher in hens fed wheat or maize than in hens fed barley (110.8 and 110.7 vs. 109.7 g/d; P = 0.014) but most of the differences were observed when the cereal was roller milled (P = 0.009 for the interaction). Also, egg production was similar for the three diets when the cereal was hammer milled but tended to be lower for the barley than for the wheat or maize diets when the cereal was roller milled (P = 0.09 for the interaction). None of the other productive or egg quality traits was affected by dietary treatment. We conclude that roller mills are useful to grind low fiber cereals, such as maize or wheat. However, the use of the roller mill might not be adequate when barley is the main cereal in diets for egg-laying hens
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