Hospital Universitari Vall d'Hebron. Institut de Recerca

En los transplantes de progenitores hematopoyéticos, la sangre de cordón umbilical es una fuente establecida de células madre hematopoyéticas que presenta como mayor ventaja una menor incidencia de enfermedades de injerto contra el huésped. Sin embargo, el bajo número de células madre obtenidas de una sola unidad limita su utilización a un número reducido de pacientes. Las células madre hematopoyéticas se definen por su capacidad de automantenimiento y reconstitución de todo el sistema hematopoyético de un huésped trasplantado. En ratón, la combinación de los marcadores de superficie Lin- LSK junto con los marcadores de la familia SLAM, ha permitido establecer una jerarquía en las poblaciones de células madre y progenitores hematopoyéticos. Sin embargo, la población de células madre hematopoyéticas humanas CD34+CD38- es heterogénea y las subpoblaciones de progenitores y células madre no están bien establecidas. Uno de los objetivos de este trabajo es determinar si los marcadores de la familia SLAM podrían redefinir la población de células madre hematopoyéticas humanas CD34+CD38- de forma similar a lo sucedido en ratón. En este trabajo se describe una nueva población de progenitores hematopoyéticos en sangre de cordón umbilical caracterizada por el fenotipo CD34+CD38-CD150+CD135-. Lon ensayos realizados tanto in vitro como in vivo han demostrado que esta población esta formada por células con capacidad de autorrenovación, de diferenciación a todos los linajes hematopoyéticos, y de reconstitución a corto y largo plazo de un modelo murino inmunodeficiente irradiado. Por otro lado, con la finalidad de obtener un número suficiente de progenitores hematopoyéticos para ser trasplantados, se han estudiado diferentes sistemas de expansión in vitro. Se ha observado que el ácido valproico (un inhibidor de las histona deacetilasas) y la activación de la vía de Notch, promueven el mantenimiento y expansión de los progenitores hematopoyéticos reduciendo los procesos de diferenciación.

Combining genetic and demographic data for the conservation of a Mediterranean habitat-forming species

The integration of ecological and evolutionary data is highly valuable for conservation planning. However, it has been rarely used in the marine realm, where the adequate design of marine protected areas (MPAs) is urgently needed. Here, we examined the interacting processes underlying the patterns of genetic structure and demographic strucuture of a highly vulnerable Mediterranean habitat-forming species (i.e. Paramuricea clavata (Risso, 1826)), with particular emphasis on the processes of contemporary dispersal, genetic drift, and colonization of a new population. Isolation by distance and genetic discontinuities were found, and three genetic clusters were detected; each submitted to variations in the relative impact of drift and gene flow. No founder effect was found in the new population. The interplay of ecology and evolution revealed that drift is strongly impacting the smallest, most isolated populations, where partial mortality of individuals was highest. Moreover, the eco-evolutionary analyses entailed important conservation implications for P. clavata. Our study supports the inclusion of habitat-forming organisms in the design of MPAs and highlights the need to account for genetic drift in the development of MPAs. Moreover, it reinforces the importance of integrating genetic and demographic data in marine conservation.

Escape over a potential barrier driven by colored noise: Large but finite correlation times

The recent theory of Tsironis and Grigolini for the mean first-passage time from one metastable state to another of a bistable potential for long correlation times of the noise is extended to large but finite correlation times.

The evolution of post-zygotic isolation barriers by immune-triggered hybrid incompatibilities in Arabidopsis thaliana

A long-standing question in evolutionary biology is what defines a species. The biological species concept considers a species as a population of individuals that interbreeds freely and produces viable offspring. Therefore, reproductive isolation is the essence of species. Hybrid necrosis is one form of post-zygotic reproductive isolation. In this chapter, we summarize what is known to date about this phenomenon and highlight progress made in the understanding of these immune-triggered hybrid incompatibilities through our research in the plant model Arabidopsis thaliana.

The evolution of post-zygotic isolation barriers by immune-triggered hybrid incompatibilities in Arabidopsis thaliana

A long-standing question in evolutionary biology is what defines a species. The biological species concept considers a species as a population of individuals that interbreeds freely and produces viable offspring. Therefore, reproductive isolation is the essence of species. Hybrid necrosis is one form of post-zygotic reproductive isolation. In this chapter, we summarize what is known to date about this phenomenon and highlight progress made in the understanding of these immune-triggered hybrid incompatibilities through our research in the plant model Arabidopsis thaliana.

The Benefits of building barrier-free: a contingent valuation of accessibilty as an attribute of housing

Estimating the social benefits of barrier-free building has always required indirect solutions, such as calculating the savings in social services, hospitalisation or adaptations made possible by the increase in accessibility. This research uses the Contingent Valuation Method to gain a direct appraisal of the benefits from barrier-free housing. When comparing two similar dwellings, with the only difference being their accessibility conditions, the 1,007 randomly chosen households that answered the direct survey would pay, on average 12.5 per cent more for being barrier-free. None of the different appraisals made on accessibility costs reaches 5 per cent. This confirms the social profitability of building without barriers and shows the potential size of the private market for those housing developers that meet the demand. Accessibility is a general concern, an economic good or attribute that most households value, irrespective of the physical conditions of their members.

The Paralympic Village: a barrier-free city

Article describing the design standards and their use for Paralympic facilities. This article was published in the book entitled Olympic Villages: a hundred years of urban planning and shared experiences compiling the papers given at the 1997 International Symposium on International Chair in Olympism (IOC-UAB).

The Coherence of the European Foreign Policy: A Real Barrier or an Academic Term?

The purpose of the present study is to break down, in a general and summarised way, the concept of the coherence of the European Foreign Policy, in order to analyse its meaning, its scope and its implications. This focus on coherence will be specifically dealt with upon the analysis of the impact of this phenomenon on single institutional framework, as defined by the Treaty on European Union.

Fault diagnosis by refining the parameter uncertainty space of nonlinear dynamic systems

This paper deals with fault detection and isolation problems for nonlinear dynamic systems. Both problems are stated as constraint satisfaction problems (CSP) and solved using consistency techniques. The main contribution is the isolation method based on consistency techniques and uncertainty space refining of interval parameters. The major advantage of this method is that the isolation speed is fast even taking into account uncertainty in parameters, measurements, and model errors. Interval calculations bring independence from the assumption of monotony considered by several approaches for fault isolation which are based on observers. An application to a well known alcoholic fermentation process model is presented

Three-dimensional morphological analysis of intracranial aneurysms: a fully automated method for aneurysm sac isolation and quantification

Morphological descriptors are practical and essential biomarkers for diagnosis andtreatment selection for intracranial aneurysm management according to the current guidelinesin use. Nevertheless, relatively little work has been dedicated to improve the three-dimensionalquanti cation of aneurysmal morphology, automate the analysis, and hence reduce the inherentintra- and inter-observer variability of manual analysis. In this paper we propose a methodologyfor the automated isolation and morphological quanti cation of saccular intracranial aneurysmsbased on a 3D representation of the vascular anatomy.

Mètriques barrier walkthrough per a persones sordes

En aquest article es presenta un conjunt de mètriques manuals, les mètriques BAW, per avaluar l'accessibilitat web d'una pàgina dins d'un context específic i ofereix la possibilitat de quantificar el grau d'accessibilitat amb una fórmula.

Thrombin-induced contraction in alveolar epithelial cells probed by traction microscopy

Contractile tension of alveolar epithelial cells plays a major role in the force balance that regulates the structural integrity of the alveolar barrier. The aim of this work was to study thrombin-induced contractile forces of alveolar epithelial cells. A549 alveolar epithelial cells were challenged with thrombin, and time course of contractile forces was measured by traction microscopy. The cells exhibited basal contraction with total force magnitude 55.0 ± 12.0 nN (mean ± SE, n = 12). Traction forces were exerted predominantly at the cell periphery and pointed to the cell center. Thrombin (1 U/ml) induced a fast and sustained 2.5-fold increase in traction forces, which maintained peripheral and centripetal distribution. Actin fluorescent staining revealed F-actin polymerization and enhancement of peripheral actin rim. Disruption of actin cytoskeleton with cytochalasin D (5 µM, 30 min) and inhibition of myosin light chain kinase with ML-7 (10 µM, 30 min) and Rho kinase with Y-27632 (10 µM, 30 min) markedly depressed basal contractile tone and abolished thrombin-induced cell contraction. Therefore, the contractile response of alveolar epithelial cells to the inflammatory agonist thrombin was mediated by actin cytoskeleton remodeling and actomyosin activation through myosin light chain kinase and Rho kinase signaling pathways. Thrombin-induced contractile tension might further impair alveolar epithelial barrier integrity in the injured lung.

Shot-noise suppression in Schottky barrier diodes

We give a theoretical interpretation of the noise properties of Schottky barrier diodes based on the role played by the long range Coulomb interaction. We show that at low bias Schottky diodes display shot noise because the presence of the depletion layer makes the effects of the Coulomb interaction negligible on the current fluctuations. When the device passes from barrier to flat band conditions, the Coulomb interaction becomes active, thus introducing correlation between different current fluctuations. Therefore, the crossover between shot and thermal noise represents the suppression due to long range Coulomb interaction of the otherwise full shot noise. Similar ideas can be used to interpret the noise properties of other semiconductor devices.

Micro-Raman study of stress distribution in local isolation structures and correlation with transmission electron microscopy

Stress in local isolation structures is studied by micro‐Raman spectroscopy. The results are correlated with predictions of an analytical model for the stress distribution and with cross‐sectional transmission electron microscopy observations. The measurements are performed on structures on which the Si3N4 oxidation mask is still present. The influence of the pitch of the periodic local isolation pattern, consisting of parallel lines, the thickness of the mask, and the length of the bird"s beak on the stress distribution are studied. It is found that compressive stress is present in the Si substrate under the center of the oxidation mask lines, with a magnitude dependent on the width of the lines. Large tensile stress is concentrated under the bird"s beak and is found to increase with decreasing length of the bird"s beak and with increasing thickness of the Si3N4 film.

Time of ruin in a risk model with generalized Erlang (n) interclaim times and a constant dividend barrier

In this paper we analyze the time of ruin in a risk process with the interclaim times being Erlang(n) distributed and a constant dividend barrier. We obtain an integro-differential equation for the Laplace Transform of the time of ruin. Explicit solutions for the moments of the time of ruin are presented when the individual claim amounts have a distribution with rational Laplace transform. Finally, some numerical results and a compare son with the classical risk model, with interclaim times following an exponential distribution, are given.