2,806 research outputs found

    Influence of temperature and time on the Eu3+ reaction with synthetic Na-Mica-n (n = 2 and 4)

    Get PDF
    Bentonite is accepted as the best clay material for the engineered barrier of Deep Geological Repositories (DGRs). The performance of clay as the main component of the engineered barrier in the DGR has been intensively studied and the structure of the selected clay mineral play a crucial role. In this sense, a new family of synthetic swelling silicates, Na-Mica-n, with tuned layer charge (n) values between 2.0 and 4.0 per unit cell has recently been synthesized and a general synthetic method has been reported. These swelling high-charge micas could be highly valuable for the decontamination of harmful cations. The ability of these micas to immobilize Eu3+ under subcritical conditions has been probed. The adsorption was in both non-specific sites (cation exchange mechanism) and specific sites (chemical reaction or surface defects adsorption). Moreover, its adsorption capacity, under the same conditions is higher than in saponite and far superior to the bentonites.Junta de Andalucía P12-FQM-567European Union 29178

    A vanishing theorem for a class of logarithmic D-modules

    Get PDF
    Let OX (resp. DX) be the sheaf of holomorphic functions (resp. the sheaf of linear differential operators with holomorphic coefficients) on X = Cn. Let D X be a locally weakly quasi-homogeneous free divisor defined by a polynomial f. In this paper we prove that, locally, the annihilating ideal of 1/fk over DX is generated by linear differential operators of order 1 (for k big enough). For this purpose we prove a vanishing theorem for the extension groups of a certain logarithmic DX–module with OX. The logarithmic DX–module is naturally associated with D (see Notation 1.1). This result is related to the so called Logarithmic Comparison Theorem

    Can snow depth be used to predict the distribution of the high Arctic aphid Acyrthosiphon svalbardicum (Hemiptera: Aphididae) on Spitsbergen?

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The Svalbard endemic aphid <it>Acyrthosiphon svalbardicum </it>(Heikinheimo, 1968) is host specific to <it>Dryas octopetala </it>L. ssp <it>octopetala </it>(Rosaceae). It has been hypothesized that the aphid is present on those areas with a thin winter snow cover and which therefore clear of snow earlier in the season. This early snow clearance results in a longer growing period and allows the aphid to experience at least the minimum number of degree days required to complete its life cycle. However, this hypothesis lacked a detailed field validation. We aimed to test the relationship between the aphid distribution and time of snow clearance at landscape scale, mapping snow depth at peak of snow accumulation for the two succeeding years 2009 and 2010 and examining site occupancy and plant phenology the following summers. Additionally, the distribution range mapped by Strathdee & Bale (1995) was revisited to address possible changes in range along the coast of the fjord.</p> <p>Results</p> <p>A linear relation between snow depth and timing of snow melt was found but with strong inter-annual and landscape variation. Both snow depth and plant phenology were found to affect patch occupancy. In August, the aphid, at the three life stages scored (viviparae, oviparae/males and eggs), was present most frequently in those <it>D. octopetala </it>patches with the most advanced plant phenology and which showed shallower snow depths in spring. However, many patches predicted to contain aphids were empty. The aphid distribution range has expanded 4.7 km towards the fjord mouth from 1995.</p> <p>Conclusions</p> <p>Snow depth alone, and hence date of snow clearance, cannot precisely define species distribution at landscape scale, as this cannot explain why are they unoccupied patches under shallow snow depths with advanced plant phenology. We nonetheless present a model Arctic system that could form the basis for long term monitoring for climate- driven species shifts.</p

    Thrombospondin-1/CD47 interaction regulates Th17 and treg differentiation in psoriasis

    Full text link
    Accumulating evidence on the role of Thrombospondin-1 (TSP-1) in the immune response has emerged during the last years. In spite of the importance of TSP-1 not only as anti-angiogenic factor but also as an immunomodulatory molecule, studies on the role of TSP-1 in psoriasis have been neglected. TSP-1 and CD47 expression were analyzed in skin samples from psoriasis patients and control subjects using RT-PCR and immunofluorescence. Expression of these molecules was also evaluated in peripheral blood CD4+ T cells, moDCs, and circulating primary DCs. The functional role of TSP-1/CD47 signaling axis in psoriasis was assessed in Th17 and Treg differentiation assays. Additionally, small interfering RNA assays specific to TSP-1 were performed in CD4+ T cells and monocyte derived DC to specifically evaluate the function of this protein. Lesional skin of psoriasis patients expressed lower TSP-1 and CD47 mRNA levels compared to non-lesional skin or skin from controls. Immunofluorescence staining revealed decreased expression of CD47 in CD45+ dermal cells from psoriasis samples compared to control subjects. Peripheral CD4+ T cells and circulating primary DCs from psoriasis also expressed lower levels of CD47 compared to controls. Although no significant differences were detected in TSP-1 expression in CD4+ T cells and moDCs between patients and controls, TSP-1 expression in psoriasis patients inversely correlated with disease activity evaluated by the Psoriasis Area and Index Activity. Furthermore, exogenous TSP-1 inhibited Th17 differentiation and stimulated the differentiation of CD4+ T cells toward Treg cells. Furthermore, RNA interference specific for TSP-1 confirmed the role of this molecule as a negative regulator of T cell activation. Because of the impact of TSP-1/CD47 signaling axis in Th17 and Treg differentiation, a dysregulated expression of these molecules in the immune cells from psoriasis patients may favor the exacerbated inflammatory response in this diseaseInstituto de Salud Carlos III (AES 2017): PI17/01972 to ED. Janssen; Spanish Ministry of Economy and Competitiveness (MINECO): Plan Nacional de Salud SAF2017-82886-R, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV); Proyecto Integrado de Excelencia PIE13/00041, Instituto de Salud Carlos III to FS-M, Instituto de Salud Carlos III PI16/02166, Universidad Autónoma de Madrid-Banco Santander (grant 2017/EEUU/03), and Red Temática de Excelencia en Investigación en Hipoxia (SAF 2017-90794-REDT) to MJC. This research has been co-financed by Fondo Europeo de Desarrollo Regional (FEDER

    Neocortical tissue recovery in severe congenital obstructive hydrocephalus after intraventricular administration of bone marrow-derived mesenchymal stem cells

    Get PDF
    BACKGROUND: In obstructive congenital hydrocephalus, cerebrospinal fluid accumulation is associated with high intracranial pressure and the presence of periventricular edema, ischemia/hypoxia, damage of the white matter, and glial reactions in the neocortex. The viability and short time effects of a therapy based on bone marrow-derived mesenchymal stem cells (BM-MSC) have been evaluated in such pathological conditions in the hyh mouse model. METHODS: BM-MSC obtained from mice expressing fluorescent mRFP1 protein were injected into the lateral ventricle of hydrocephalic hyh mice at the moment they present a very severe form of the disease. The effect of transplantation in the neocortex was compared with hydrocephalic hyh mice injected with the vehicle and non-hydrocephalic littermates. Neural cell populations and the possibility of transdifferentiation were analyzed. The possibility of a tissue recovering was investigated using 1H High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance (1H HR-MAS NMR) spectroscopy, thus allowing the detection of metabolites/osmolytes related with hydrocephalus severity and outcome in the neocortex. An in vitro assay to simulate the periventricular astrocyte reaction conditions was performed using BM-MSC under high TNFα level condition. The secretome in the culture medium was analyzed in this assay. RESULTS: Four days after transplantation, BM-MSC were found undifferentiated and scattered into the astrocyte reaction present in the damaged neocortex white matter. Tissue rejection to the integrated BM-MSC was not detected 4 days after transplantation. Hyh mice transplanted with BM-MSC showed a reduction in the apoptosis in the periventricular neocortex walls, suggesting a neuroprotector effect of the BM-MSC in these conditions. A decrease in the levels of metabolites/osmolytes in the neocortex, such as taurine and neuroexcytotoxic glutamate, also indicated a tissue recovering. Under high TNFα level condition in vitro, BM-MSC showed an upregulation of cytokine and protein secretion that may explain homing, immunomodulation, and vascular permeability, and therefore the tissue recovering. CONCLUSIONS: BM-MSC treatment in severe congenital hydrocephalus is viable and leads to the recovery of the severe neurodegenerative conditions in the neocortex. NMR spectroscopy allows to follow-up the effects of stem cell therapy in hydrocephalus.España Instituto Carlos III , PI15/00619 (to AJJ), PI19/00778 (to AJJ and PPG), PI15/00796, and PI18/01557España Ministerio de Educación, Cultura y Deporte FPU13/02906España, Ministerio de Economía y Competitividad RYC-2014-16980España, FEDER Andalucía y Universidad de Málaga UMA18-FEDERJA-27

    Phosphorylation and dephosphorylation of tau protein by the catalytic subunit of PKA, as probed by electrophoretic mobility retard

    Full text link
    Background: Tau is a microtubule associated protein that regulates the stability of microtubules and the microtubule-dependent axonal transport. Its hyperphosphorylated form is one of the hallmarks of Alzheimer's disease and other tauopathies and the major component of the paired helical filaments that form the abnormal proteinaceous tangles found in these neurodegenerative diseases. It is generally accepted that the phosphorylation extent of tau is the result of an equilibrium in the activity of protein kinases and phosphatases. Disruption of the balance between both types of enzyme activities has been assumed to be at the origin of tau hyperphosphorylation and the subsequent toxicity and progress of the disease. Objective: We explore the possibility that, beside the phosphatase action on phosphorylated tau, the catalytic subunit of PKA catalyzes both tau phosphorylation and also tau dephosphorylation, depending on the ATP/ADP ratio. Methods: We use the shift in the relative electrophoretic mobility suffered by different phosphorylated forms of tau, as a sensor of the catalytic action of the enzyme. Results: The results are in agreement with the long-known thermodynamic reversibility of the phosphorylation reaction (ATP + Protein = ADP+Phospho-Protein) catalyzed by PKA and many other protein kinases. Conclusion: The results contribute to put the compartmentalized energy state of the neuron and the mitochondrial-functions disruption upstream of tau-related pathologiesFinancial support has been provided by a grant from the Spanish Government PGC2018 096177-B-10

    Improved Contrast Sensitivity DVS and its Application to Event-Driven Stereo Vision

    Get PDF
    This paper presents a new DVS sensor with one order of magnitude improved contrast sensitivity over previous reported DVSs. This sensor has been applied to a bio-inspired event-based binocular system that performs 3D event-driven reconstruction of a scene. Events from two DVS sensors are matched by using precise timing information of their ocurrence. To improve matching reliability, satisfaction of epipolar geometry constraint is required, and simultaneously available information on the orientation is used as an additional matching constraint.Ministerio de Economía y Competitividad PRI-PIMCHI-2011-0768Ministerio de Economía y Competitividad TEC2009-10639-C04-01Junta de Andalucía TIC-609

    Differential Effects of Increasing Salinity on Germination and Seedling Growth of Native and Exotic Invasive Cordgrasses

    Get PDF
    Soil salinity is a key environmental factor influencing germination and seedling establishment in salt marshes. Global warming and sea level rise are changing estuarine salinity, and may modify the colonization ability of halophytes. We evaluated the effects of increasing salinity on germination and seedling growth of native Spartina maritima and invasive S. densiflora from wetlands of the Odiel-Tinto Estuary. Responses were assessed following salinity exposure from fresh water to hypersaline conditions and germination recovery of non-germinated seeds when transferred to fresh water. The germination of both species was inhibited and delayed at high salinities, while pre-exposure to salinity accelerated the speed of germination in recovery assays compared to non-pre-exposed seeds. S. densiflora was more tolerant of salinity at germination than S. maritima. S. densiflora was able to germinate at hypersalinity and its germination percentage decreased at higher salinities compared to S. maritima. In contrast, S. maritima showed higher salinity tolerance in relation to seedling growth. Contrasting results were observed with differences in the tidal elevation of populations. Our results suggest S. maritima is a specialist species with respect to salinity, while S. densiflora is a generalist capable of germination of growth under suboptimal conditions. Invasive S. densiflora has greater capacity than native S. maritima to establish from seed with continued climate change and sea level rise.Ministerio de Educación, Cultura y Deporte (FPU14/06556

    Turismo de cruceros en la interfaz puerto-ciudad Mediterránea: nueva época del waterfront, con beneficios en un Smart Destination

    Get PDF
    This study is part of the literature on the cruise industry that focuses on the waterfront phenomenon and on the development of a new cruise-city interface promoted by cruise tourism. The development of a new era of waterfronts with the implication of cruise tourism is used as the starting hypothesis. It affects both the waterfront and the port, under the development of a new image as a gateway to the city and Mediterranean cities (mainly their historical downtown, since it is the attractive cultural area) which are part of the interventions in the search for the port-city relationship. In this sense, the positive and negative impacts of this type of tourism are listed after studying different cases of Mediterranean port cities. The integration through the development of a Smart Cruise Port in a Smart Destination, which would benefit the cruise-city interrelationship, is presented as a proposal.Este estudio se sitúa en la literatura sobre la industria de cruceros atendiendo al fenó¬meno waterfront y al desarrollo de una nueva interfaz crucero-ciudad promovida por el turismo de cruceros. Se parte de una hipótesis, el desarrollo de una nueva época del water¬front con la implicación del turismo de cruceros, que incide tanto en el waterfront como en el puerto, bajo el desarrollo de una nueva imagen como puerta de entrada a la ciudad, y la ciudad mediterránea, principalmente su casco histórico, al ser el área cultural atrayente, que forman parte de las intervenciones en la búsqueda de la relación puerto-ciudad. En este sen¬tido, se ponen de manifiesto los impactos positivos y negativos que trae consigo este tipo de turismo, tras estudiar diferentes casos de ciudades portuarias mediterráneas y se concluye, con la propuesta de una integración a través del desarrollo de un Smart Cruise Port en un Smart Destination, que beneficiaría la interrelación crucero-ciudad
    corecore