166 research outputs found

    Modelling the spatio-temporal evolution of H-3 in the waters of the River Tagus

    Get PDF
    Measurements of tritium specific activity levels and of temperatures in waters of the Torrejo´neTagus reservoir (Spain) showed that their radioactive characteristics were basically influenced by the radioactive liquid effluent from the Almaraz Nuclear Power Plant. This enters the Torrejo´neTagus reservoir via the Arrocampo cooling reservoir, which exchanges water with the first. We studied the temporal and spatial (in two dimensions) evolution of the mentioned parameters for years 1997 and 1998. The tritium levels were found to be significantly correlated with temperature. Two numerical models were constructed for a quantitative study of the tritium levels along Torrejo´n reservoir: a 1D model was used for the dispersion of tritium along the whole length of the reservoir, and a 2D depth-averaged model was used for a detailed study of the area where tritium is released into the reservoir. Both models solve the hydrodynamic equa tions, to obtain the currents induced by the exchanges of water between the reservoirs in the River Tagus and Arrocampo, and the advection/diffusion equation to calculate the dispersion of tritium. In general, the model results were in agreement with the experimental observationsJunta de Extremadura 2PR02A02

    Effect of size and oxidation state of size-controlled rhodium nanoparticles on the aqueous-phase hydrodechlorination of 4-chlorophenol

    Full text link
    Unsupported size-controlled Rh nanoparticles of different size and oxidation state were tested as catalysts models in aqueous phase hydrodechlorination (303-318K, 1atm) using 4-chlorophenol (4-CP) as target compound. A chemical reduction method was employed for the synthesis of the nanoparticles using methanol and poly(N-vinyl-2-pyrrolidone) (PVP) as reducing and capping agent, respectively. The size of Rh nanoparticles was in a narrow range (1.9-4.9nm) whereas Rhn+/Rh0 ratio values were found within a wide range (0.56-3.89).High 4-CP conversion values (c.a. 100%) were achieved at low Rh concentration (2.45·10-3gL-1). Phenol, cyclohexanone, cyclohexanol and traces of cyclohexane were identified as reaction products. A wide range of activity values (1.7-29.4mmolg-1min-1) were obtained, being equivalent to the measured in a previous work with unsupported Pd nanoparticles, in spite of the fact that Rh supported catalysts have generally been reported as less active than Pd ones in liquid phase hydrodechlorination. As the size of Rh nanoparticles decreased the activity increased reaching a maximum at 2.8nm, lower size values leading to a significant decrease of activity. A remarkable dependence of activity on the Rhn+/Rh0 ratio was found, thus a higher activity corresponded to a higher relative amount of zero-valent Rh in the nanoparticles samples. Regression models were developed in order to address the significance of nanoparticles size and oxidation state for the prediction of selectivity to cyclohexanone and cyclohexanol at varying reaction times. A crossed effect of particle size and Rhn+/Rh0 ratio was identified as a significant factor influencing the selectivityWe greatly appreciate financial support from the Spanish MCYT (CTQ2009-09983 and CTQ2012-32821) and CAM (REMTAVARES S-2009/AMB-1588). J.A. Baeza thanks to the Spanish MICINN a research grant (BES-2010-030059

    How 3D patient-specific instruments improve accuracy of pelvic bone tumour resection in a cadaveric study

    Get PDF
    To assess the accuracy of patient-specific instruments (PSIs) versus standard manual technique and the precision of computer-assisted planning and PSI-guided osteotomies in pelvic tumour resection. CT scans were obtained from five female cadaveric pelvises. Five osteotomies were designed using Mimics software: sacroiliac, biplanar supra-acetabular, two parallel iliopubic and ischial. For cases of the left hemipelvis, PSIs were designed to guide standard oscillating saw osteotomies and later manufactured using 3D printing. Osteotomies were performed using the standard manual technique in cases of the right hemipelvis. Post-resection CT scans were quantitatively analysed. Student's t -test and Mann-Whitney U test were used. Compared with the manual technique, PSI-guided osteotomies improved accuracy by a mean 9.6 mm (p 5 mm and 27% (n = 8) were > 10 mm. In the PSI cases, deviations were 10% (n = 3) and 0 % (n = 0), respectively. For angular deviation from pre-operative plans, we observed a mean improvement of 7.06° (p < 0.001) in pitch and 2.94° (p < 0.001) in roll, comparing PSI and the standard manual technique. In an experimental study, computer-assisted planning and PSIs improved accuracy in pelvic tumour resections, bringing osteotomy results closer to the parameters set in pre-operative planning, as compared with standard manual techniques. Cite this article : A. Sallent, M. Vicente, M. M. Reverté, A. Lopez, A. Rodríguez-Baeza, M. Pérez-Domínguez, R. Velez. How 3D patient-specific instruments improve accuracy of pelvic bone tumour resection in a cadaveric study. Bone Joint Res 2017;6:577-583. DOI: 10.1302/2046-3758.610.BJR-2017-0094.R1

    Effect of structural ordering of the carbon support on the behavior of Pd catalysts in aqueous-phase hydrodechlorination

    Full text link
    Catalysts consisting of Pd supported on virgin and heat-treated carbon blacks (homemade and commercial), graphites (natural and synthetic) and commercial carbon nanofibers were prepared and tested in the aqueous phase hydrodechlorinaton (HDC) of 4-chlorophenol (4-CP) under near ambient conditions (30 °C, 1 atm) in order to explore the effect of the support on the catalytic behavior. The homemade graphitized supports were prepared from commercial carbon black (CB) and from a carbon black-like material (CBPE) obtained from pyrolysis of low-density polyethylene. All the catalysts prepared yielded complete 4-CP conversion, although a wide range of activity was observed (10.7–173.5 mmol gPd−1 min−1). The graphitized carbon black provided the most active catalysts, showing Pd nanoparticles around 3 nm in size and a well-balanced contribution of Pd species (Pdn+/Pd0 = 0.9). Substantial differences of activity were found between the graphitized and not graphitized supports, even for catalysts with similar Pd nanoparticle size. The higher activity of the catalysts with graphitized supports can be partly associated to a more balanced initial Pdn+ to Pd0 ratio. Moreover, higher selectivity to hydrogenation products (cyclohexanone) was also achieved with those catalysts due to a higher contribution of the Pd0 speciesThe authors greatly appreciate financial support from the Spanish MINECO (CTQ2012-32821

    Programmed cell senescence during mammalian embryonic development

    Get PDF
    Cellular senescence disables proliferation in damaged cells, and it is relevant for cancer and aging. Here, we show that senescence occurs during mammalian embryonic development at multiple locations, including the mesonephros and the endolymphatic sac of the inner ear, which we have analyzed in detail. Mechanistically, senescence in both structures is strictly dependent on p21, but independent of DNA damage, p53, or other cell-cycle inhibitors, and it is regulated by the TGF-beta/SMAD and PI3K/FOXO pathways. Developmentally programmed senescence is followed by macrophage infiltration, clearance of senescent cells, and tissue remodeling. Loss of senescence due to the absence of p21 is partially compensated by apoptosis but still results in detectable developmental abnormalities. Importantly, the mesonephros and endolymphatic sac of human embryos also show evidence of senescence. We conclude that the role of developmentally programmed senescence is to promote tissue remodeling and propose that this is the evolutionary origin of damage-induced senescence

    Evaluation of the nutritional quality of Chaetoceros muelleri Schütt (Chaetocerotales: Chaetocerotaceae) and Isochrysis sp. (Isochrysidales: isochrysidaceae) grown outdoors for the larval development of Litopenaeus vannamei (Boone, 1931) (Decapoda: Penaeidae)

    Get PDF
    The biomass, proximal composition and fatty acid profile of Isochrysis sp., Chaetoceros muelleri and their mixture, grown under greenhouse conditions, were evaluated. The nutritional value of both species supplied as the monoalgal (Chaetoceros muelleri: Diet I, and Isochrysis sp. Diet II) and mixed diet (Diet III) for larval Litopenaeus vannamei was also assessed on the basis of the development and biochemical composition of the larvae. The highest protein levels were obtained in Diets I and II (40% and 35%, respectively). No significant differences in larval survival were found among the diets; however, larvae fed on Diet II had the lowest mean larval length

    Autoimmune/inflammatory syndrome induced by adjuvants: a review

    Get PDF
    The autoimmune/inflammatory syndrome induced by adjuvants (ASIA) includes several autoimmune conditions and phenomena that occur after exposure to substances with adjuvant activity. The spectrum of the disease is heterogeneous with respect to the clinical presentation as well as the severity of the clinical manifestations. Different substances and medical devices with adjuvant activity are currently known, such as vaccines, oils, silicones, mineral salts, lipopolysaccharides, peptidoglycans, among others. These adjuvants are immunological molecules that function through potentiation of antigen-specific immune responses. Thus, the etiopathogenesis of ASIA syndrome involves a multifactorial interaction between environmental factors and genetic predisposition, and secondary activation of the adaptive and innate arms of the immune system through various mechanisms. Although in some reported cases the ASIA syndrome improves considerably when removing the implants, there are no conclusive results for the clinical benefit of removing the implants, so it is necessary to carry out further basic, clinical and surgical investigations in order to determine the best therapeutic decision

    Patrones de abundancia de la macrofauna asociada a macroalgas marinas a largo de la Península Ibérica

    Get PDF
    macroalgae were studied on a spatial scale along the Iberian Peninsula. Nineteen stations and four dominant algae were selected (intertidal zone: Corallina elongata and Asparagopsis armata; subtidal zone: Stypocaulon scoparium and Cladostephus spongiosus). Five environmental factors were also considered (seawater temperature, conductivity, dissolved oxygen, turbidity and pH). The Atlantic coast was characterized by lower temperature and conductivity as well as higher values of oxygen and turbidity than the Mediterranean coast. A total of 106274 macrofaunal specimens were sorted and examined (68% arthropods, 27% molluscs, 4% annelids and 1% echinoderms). Crustaceans were the dominant group in all the macroalgae (ca. 80% in C. elongata and A. armata, ca. 50% in S. scoparium and C. spongiosus) followed by molluscs, which were more abundant in the subtidal algae (ca. 40%) than in intertidal ones (ca.10%). Abundance patterns of macrofauna along the Iberian Peninsula were similar in the four studied algae. Most of crustaceans belonged to the order Amphipoda, which showed high densities (>1000 ind/1000 ml algae) along the whole Peninsula; isopods showed the highest abundances in the Atlantic, while tanaids, cumaceans and decapods were more abundant in the Mediterranean. Among molluscs, gasteropods showed highest abundances along the Atlantic coasts, whereas bivalves showed higher densities along the MediterraneanSe llevó a cabo un estudio espacial de los patrones de abundancia y distribución de la macrofauna asociada a macroalgas a lo largo de la Península Ibérica. Se seleccionaron 19 estaciones y 4 algas dominantes (zona intermareal: Corallina elongata y Asparagopsis armata; zona submareal: Stypocaulon scoparium y Cladostephus spongiosus). Se consideraron también cinco variables ambientales (temperatura del agua, conductividad, oxígeno disuelto, turbidez y pH). La costa atlántica se caracterizó por valores más bajos de temperatura y conductividad, y más altos de oxígeno y turbidez. Se examinaron 106274 individuos de la macrofauna (68% artrópodos, 27% moluscos, 4% anélidos y 1% equinodermos). Los crustáceos fueron dominantes en todas las macroalgas (alrededor del 80% en C. elongata y A. armata, y en torno al 50% en S. scoparium y C. spongiosus), seguidos por los moluscos, que fueron más abundantes en el submareal (40%) que en el intermareal (10%). Los patrones de abundancia de la macrofauna a lo largo de la Península Ibérica fueron similares en las cuatro algas estudiadas. La mayoría de los crustáceos pertenecieron al orden Amphipoda, que mostró densidades muy altas (>1000 ind/1000 ml alga) en toda la Península; los isópodos mostraron las mayores densidades en el Atlántico, mientras que los tanaidáceos, cumáceos y decápodos fueron más abundantes en el Mediterráneo. Entre los moluscos, los gasterópodos mostraron abundancias mayores en el Atlántico, mientras que los bivalvos dominaron en el Mediterráneo. Teniendo en cuenta que todas las estaciones seleccionadas no tenían influencia antrópica importante, los patrones de abundancia obtenidos podrían explicarse en base a diferencias naturales en la temperatura del agua, oxígeno, conductividad y turbidez, existiendo un gradiente transicional entre taxones de aguas más cálidas (del norte de Africa y del Mediterráneo) y taxones de aguas más frías (del Mar del Norte y el Ártico)

    Exploration of cannabis use and polygenic risk scores on the psychotic symptom progression of a FEP cohort

    Get PDF
    Cannabis use is highly prevalent in first-episode psychosis (FEP) and plays a critical role in its onset and prognosis, but the genetic underpinnings promoting both conditions are poorly understood. Current treatment strategies for cannabis cessation in FEP are clearly inefficacious. Here, we aimed to characterize the association between cannabis-related polygenic risk scores (PRS) on cannabis use and clinical course after a FEP. A cohort of 249 FEP individuals were evaluated during 12 months. Symptom severity was measured with the Positive and Negative Severity Scale and cannabis use with the EuropASI scale. Individual PRS for lifetime cannabis initiation (PRSCI) and cannabis use disorder (PRSCUD) were constructed. Current cannabis use was associated with increased positive symptoms. Cannabis initiation at younger ages conditioned the 12-month symptom progression. FEP patients with higher cannabis PRSCUD reported increased baseline cannabis use. PRSCI was associated with the course of negative and general symptomatology over follow-up. Cannabis use and symptom progression after a FEP were modulated by cannabis PRS, suggesting that lifetime initiation and use disorders may have partially independent genetic factors. These exploratory results may be the first step to identify those FEP patients more vulnerable to cannabis use and worse outcomes to ultimately develop tailored treatments
    corecore