76 research outputs found

    Theoretical modelling of quaternary GaInAsSb/GaAs self-assembled quantum dots

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    Trabajo presentado al "Quantum Dot", celebrado en Nottingham (UK) del 26 al 30 de Abril de 2010.InAs/GaAs quantum dots exposed to Sb after growth exhibit spectral changes. We study in the present paper an idealized nanostructure consisting of a homogeneous distribution of the quaternary GaInAsSb surrounded by a barrier of GaAs. We nd that the valence band o set is a critical parameter in modelling its electronic structure. Depending on this value, we predict a transition from type-I to type-II band alignment at a di erent Sb concentration. The addition of Sb to reduce the transition energy while keeping a type-I alignment is only of bene t at low Sb concentrationThis work was supported by the Spanish MICINN (projects TEC2008-06756-C03-01/02/TEC, CONSOLIDER INGENIO 2010 CSD2006-0019 and CSD2009-00013), the Junta de Andalucía (PAI research groups TEP-120 and TIC-145; project P08-TEP-03516) and Comunidad Autónoma de Madrid S2009ESP-1503.Peer reviewe

    Compositional mapping by Z-contrast imaging

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    This research was sponsored by the Office of Basic Energy Sciences, Materials Sciences and Engineering Division, U.S. Department of Energy (SJP, MV), by the Spanish MCI (projects CONSOLIDER INGENIO 2010 CSD2009-00013 andTEC2008-06756-C03-02/TEC,) and the Junta de Andalucía (PAI research’s groups TEP-120 and TIC-145; project P08-TEP-03516).Peer Reviewe

    Prevalence estimation of significant fibrosis because of NASH in Spain combining transient elastography and histology

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    Acord transformatiu CRUE-CSICBackground & Aims: Non-alcoholic fatty liver disease (NAFLD) has become a major public health problem, but the prevalence of fibrosis associated with non-alcoholic steatohepatitis (NASH) is largely unknown in the general population. This study aimed to provide an updated estimation of the prevalence of NASH fibrosis in Spain. Methods: This was an observational, retrospective, cross-sectional, population-based study with merged data from two Spanish datasets: a large (N = 12 246) population-based cohort (ETHON), including transient elastography (TE) data, and a contemporary multi-centric biopsy-proven NASH cohort with paired TE data from tertiary centres (N = 501). Prevalence for each NASH fibrosis stage was estimated by crossing TE data from ETHON dataset with histology data from the biopsy-proven cohort. Results: From the patients with valid TE in ETHON dataset (N = 11 440), 5.61% (95% confidence interval [95% CI]: 2.53-11.97) had a liver stiffness measurement (LSM) ≥ 8 kPa. The proportion attributable to NAFLD (using clinical variables and Controlled Attenuation Parameter) was 57.3% and thus, the estimated prevalence of population with LSM ≥ 8 kPa because of NAFLD was 3.21% (95% CI 1.13-8.75). In the biopsy-proven NASH cohort, 389 patients had LSM ≥ 8 kPa. Among these, 37% did not have significant fibrosis (F2-4). The estimated prevalence of NASH F2-3 and cirrhosis in Spain's adult population were 1.33% (95% CI 0.29-5.98) and 0.70% (95% CI 0.10-4.95) respectively. Conclusions: These estimations provide an accurate picture of the current prevalence of NASH-related fibrosis in Spain and can serve as reference point for dimensioning the therapeutic efforts that will be required as NASH therapies become available

    Cueva de La Cocina (Dos Aguas, Valencia) en el marco del Proyecto de Investigación Har2012-33111 “Meso Cocina: Los Últimos Caza-Recolectores y el Paradigma de la Neolitización en el Mediterráneo Peninsular”

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    Comunicación oral en el VI Congreso del Neolítico en la Península Ibérica: “Los cambios económicos y sus implicaciones sociales durante el Neolítico de la Península Ibérica”, 22-26 junio 2016 GranadaEl objetivo de esta comunicación es dar a conocer los resultados preliminares del proyecto HAR12-33111 “MesoCocina: los últimos caza-recolectores y el paradigma de la neolitización en el Mediterráneo peninsular” que ha tenido como eje de actuación el análisis pormenorizado del excepcional registro prehistórico recuperado en Cueva de la Cocina (Dos Aguas, Valencia). En el transcurso de los tres últimos años se ha procedido al análisis de las colecciones correspondientes a las excavaciones efectuadas por Ll. Pericot en los años 40 del pasado siglo así como aquellos resultados de las campañas dirigidas posteriormente por J. Fortea en los años 70. Al mismo tiempo se han llevado a cabo dos intervenciones de campo en la cavidad con el fin de obtener información precisa sobre las características de una secuencia clave a propósito de las ocupaciones del Mesolítico final en el Mediterráneo occidental, y que además contiene evidencias de frecuentaciones posteriores, desde el Neolítico Antiguo hasta la edad del Bronce. El establecimiento de un marco radiométrico preciso ha sido una de las prioridades junto a la reconstrucción tridimensional de todas las actuaciones realizadas hasta la fecha en el sitio. Bajo esta óptica procederemos a reevaluar la variabilidad de la cultura material, de las actividades de subsistencia, del mundo simbólico y las conexiones sociales en el entorno medioambiental donde se llevaron a cabo desde una amplia perspectiva diacrónica, entre el inicio del IX y el III milenio cal BP. Ciñéndonos al marco de este congreso nos centraremos especialmente en los nuevos datos relativos a la secuencia de los últimos caza-recolectores y el primer Neolítico en la cavidad.Peer Reviewe

    Pathological Features in Paediatric Patients with TK2 Deficiency

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    Thymidine kinase (TK2) deficiency causes mitochondrial DNA depletion syndrome. We aimed to report the clinical, biochemical, genetic, histopathological, and ultrastructural features of a cohort of paediatric patients with TK2 deficiency. Mitochondrial DNA was isolated from muscle biopsies to assess depletions and deletions. The TK2 genes were sequenced using Sanger sequencing from genomic DNA. All muscle biopsies presented ragged red fibres (RRFs), and the prevalence was greater in younger ages, along with an increase in succinate dehydrogenase (SDH) activity and cytochrome c oxidase (COX)-negative fibres. An endomysial inflammatory infiltrate was observed in younger patients and was accompanied by an overexpression of major histocompatibility complex type I (MHC I). The immunofluorescence study for complex I and IV showed a greater number of fibres than those that were visualized by COX staining. In the ultrastructural analysis, we found three major types of mitochondrial alterations, consisting of concentrically arranged lamellar cristae, electrodense granules, and intramitochondrial vacuoles. The pathological features in the muscle showed substantial differences in the youngest patients when compared with those that had a later onset of the disease. Additional ultrastructural features are described in the muscle biopsy, such as sarcomeric de-structuration in the youngest patients with a more severe phenotype

    Stress compensation by GaP monolayers for stacked InAs/GaAs quantum dots solar cells

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    Trabajo presentado en el 33rd IEEE Photovoltaic Specialists Conference, celebrado en San Diego, CA (Estados Unidos), del 11 al 16 de mayo de 2008In this work we report the stacking of 10 and 50 InAs quantum dots layers using 2 monolayers of GaP for stress compensation and a stack period of 18 nm on GaAs (001) substrates. Very good structural and optical quality is found in both samples. Vertical alignment of the dots is observed by transmission electron microscopy suggesting the existence of residual stress around them. Photocurrent measurements show light absorption up to 1.2 µm in the nanostructures together with a reduction in the blue response of the device. As a result of the phosphorus incorporation in the barriers, a very high thermal activation energy (431 meV) has also been obtained for the quantum dot emission.The authors gratefully acknowledge financial support by the Spanish MEC and CAM through projects 200560M089, S-05050/ENE-0310, TEC-2005-05781-C03- 01 and -02, Consolider-Ingenio 2010 CSD2006-0004, the Junta de Andalucia (project TEP383, group TEP120) and by the European Commission through the SANDIE Network of Excellence (NMP4-CT-2004-500101).Peer reviewe

    Evaluation of chromosome organization and microtubule arrangement in goat (capra aegragrus) oocytes after vitrification, in vitro maturation and fertilization, and early embryo development

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    Objective: Evaluate the use of Ethylene Glycol (EG), Dimethyl Sulfoxide (DMSO), Sucrose and Fetal Bovine Serum (FBS) as cryoprotectants and their effect on the organization of chromosomes and the arrangement of microtubules, during the vitrification process in goat oocytes matured in vitro and in the development of preimplantation embryos produced in vitro. Design/methodology/approach: In vitro matured oocytes were divided into 3 groups (control group, cryoprotectant exposed group, vitrified group). A mixture of 15% EG, 15% DMSO, 0.4 M sucrose and 20% FBS was used for the vitrification using the Cryotop device. In vitro matured oocytes were warmed and afterwards each group was divided into two more groups. Both groups were subjected to immunofluorescence, the first group to observe the damage produced to the chromosomes and microtubules and the second group to observe the effect on the in vitro embryo development. Results: The combined use of 15% EG, 15% DMSO, 0.4 M Sucrose and 20% FBS during vitrification did not prevent cryoinjuries in goat oocytes and in vitro produced embryos, since embryo development was disrupted before the blastocyst stage by stopping cleavage at the morula stage. This disruption was associated with chromosome decondensation and the absence of a microtubule network, thereby hindering chromosomal segregation. Limitations on study/implications: The effect of conventional cryoprotectants on chromosomes and microtubules arrangement on vitrified goat oocytes and in vitro embryo production. Findings/conclusions: The combined use of 15% EG, 15% DMSO, 0.4 M sucrose and 20% FBS as vitrification cryoprotectants did not prevent cryoinjuries in caprine oocytes and did not improve caprine embryo development in vitro

    Sera from Patients with NMOSD Reduce the Differentiation Capacity of Precursor Cells in the Central Nervous System

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    Introduction: AQP4 (aquaporin-4)–immunoglobulin G (IgG)-mediated neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease that affects the central nervous system, particularly the spinal cord and optic nerve; remyelination capacity in neuromyelitis optica is yet to be determined, as is the role of AQP4–IgG in cell differentiation. Material and Methods: We included three groups—a group of patients with AQP4–IgG-positive neuromyelitis optica, a healthy group, and a sham group. We analyzed differentiation capacity in cultures of neurospheres from the subventricular zone of mice by adding serum at two different times: early and advanced stages of differentiation. We also analyzed differentiation into different cell lines. Results and Conclusions: The effect of sera from patients with NMOSD on precursor cells differs according to the degree of differentiation, and probably affects oligodendrocyte progenitor cells from NG2 cells to a lesser extent than cells from the subventricular zone; however, the resulting oligodendrocytes may be compromised in terms of maturation and possibly limited in their ability to generate myelin. Furthermore, these cells decrease in number with age. It is very unlikely that the use of drugs favoring the migration and differentiation of oligodendrocyte progenitor cells in multiple sclerosis would be effective in the context of neuromyelitis optica, but cell therapy with oligodendrocyte progenitor cells seems to be a potential alternative

    Analyzing factors that influence the folk use and phytonomy of 18 medicinal plants in Navarra

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    BACKGROUND: This article analyzes whether the distribution or area of use of 18 medicinal plants is influenced by ecological and cultural factors which might account for their traditional use and/or phytonymy in Navarra. This discussion may be helpful for comparative studies, touching as it does on other ethnopharmacological issues: a) which cultural and ecological factors affect the selection of medicinal plants; b) substitutions of medicinal plants in popular medicine; c) the relation between local nomenclature and uses. To analyze these questions, this paper presents an example of a species used for digestive disorders (tea and camomile: Jasonia glutinosa, J. tuberosa, Sideritis hyssopifolia, Bidens aurea, Chamaemelum nobile, Santolina chamaecyparissus...), high blood pressure (Rhamnus alaternus, Olea europaea...) or skin diseases (Hylotelephium maximum, H. telephium, Anagallis arvensis, A. foemina). METHODS: Fieldwork began on January 2004 and continued until December 2006. During that time we interviewed 505 informants in 218 locations in Navarra. Information was collected using semi-structured ethnobotanical interviews, and we subsequently made maps using Arc-View 8.0 program to determine the area of use of each taxon. Each map was then compared with the bioclimatic and linguistic map of Navarra, using the soil and ethnographic data for the region, and with other ethnobotanical and ethnopharmacological studies carried out in Europe. RESULTS: The results clearly show that ecological and cultural factors influence the selection of medicinal plants in this region. Climate and substrate are the most important ecological factors that influence the distribution and abundance of plants, which are the biological factors that affect medicinal plant selection. CONCLUSION: The study of edaphological and climatological factors, on the one hand, and culture, on the other, can help us to understand why a plant is replaced by another one for the same purposes, either in the same or in a different area. In many cases, the cultural factor means that the use of a species is more widespread than its ecological distribution. This may also explain the presence of synonyms and polysemies which are useful for discussing ethnopharmacological data
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