426 research outputs found
Single extraction tests for risk assessment of arsenic and heavy metals in polluted soils from mining activities
Se presentan los resultados obtenidos en la aplicación de 3 métodos de extracción simple, para evaluar el grado de movilidad y biodisponibilidad de As, Cd, Cu, Pb y Zn, en suelos afectados por la actividad minera. Los métodos desarollados están basados en el empleo de agentes extractantes de diferente naturaleza y UPS, con determinación por ICP-AES. El estudio estadístico de los resultados obtenidos, permitió establecer el método más adecuado en función del elemento analizado, debido a su diferente asociación a los componentes del suelo
Arsenic speciation in plants by HPLC-(UV)-HG-AFS: Optimisation of the extraction method and application to native plant species from soils polluted by mining activities
Se ha optimizado el método de extracción de especies de arsénico hidrosolubles en muestras de plantas terrestres procedentes de suelos contaminados por actividad minera. La especies extraídas se han determinado mediante HPLC-(UV)-HG-AFS
Application of ultrasound probe sonication for arsenic and heavy metal extraction in soils
Se ha optimizado un método de extracción de arsénico y metales pesados en suelos contaminados procedentes de actividad minera, mediante la aplicación de la sonda de ultrasonidos focalizada
Arsenic and heavy metal uptake and accumulation in native plant species from soils polluted by mining activities
Arsenic and heavy metal (specifically Cd, Cr, Cu, Ni, Pb, and Zn) uptake, translocation, and accumulation in ten native plant species spontaneously growing in soils polluted by mining activities were studied, with a focus on future phytoremediation work in polluted soils. Plant and soil samples were collected in the vicinity of the Mónica mine (NW Madrid, Spain). Soil analysis showed the ability of native plants for growing in soils with high concentration levels of Cd, Cu, Pb, Zn, and especially As. From these elements, the highest percentage of extractable elements was found for Cd and the lowest for Pb. A highly significant correlation was observed between total and extractable element concentrations in soils, except for Cu, indicating that total concentration is the most relevant factor for element mobility in these soils. Extractable elements in soils were better correlated with concentrations in plants than total elements in soils; thus, extraction methods applied are suitable to estimate the element phytoavailable fraction in soils, which depends on the plant species and not only on the element mobility in soils. High element concentrations were found in the aboveground parts of Corrigiola telephiifolia (As and Pb), Jasione montana (Cd and Zn), and Digitalis thapsi (As, Cd, Cu, Pb and Zn). However, considering the translocation and accumulation factors, together with the concentration levels found in roots and aboveground parts, only C. telephiifolia could be considered a Pb accumulator and an As hyperaccumulator plant, which could be used for future phytoremediation work in soils polluted with As
Prothrombotic profile in patients with vasospastic or non vasospastic angina and non significant coronary stenosis
Background: Patients with vasospastic (VA) or non vasospastic angina (NVA) without significant coronary stenosis have a reduced risk of infarction but is unclear whether or not this may be attributable to a lack of prothrombotic profile - similar to that present in patients with stable coronary artery disease (CAD). Methods: Plasma levels of von Willebrand factor, total and free tissue factor pathway inhibitor, plasminogen activator inhibitor-1, and fibrinogen were analyzed in 15 patients with stable VA and 23 with NVA, all with vasoconstrictive response to acetylcholine although with different severity. Results were compared with those of 20 age-matched controls and 10 patients with CAD. Results: Plasma levels of von Willebrand factor in patients with VA or NVA were higher than in controls (207 ± 62 and 203 ± 69% vs 121 ± 38%, p < 0.001) and tended to be lower than in CAD patients (264 ± 65, p = 0.145). They also presented higher total tissue factor pathway inhibitor (123 ± 18 and 111 ± 25 vs 88 ± 14, ng/ml p < 0.001) and plasminogen activator inhibitor-1 levels than controls (51 ± 30 and 52 ± 31% vs 19 ± 9 ng/ml, p < 0.001) and similar to CAD patients (134 ± 23 and 62 ± 31, respectively, ns). Moreover, free tissue factor pathway inhibitor plasma levels were lower than controls (18 ± 5 and 17 ± 5 vs 23 ± 8 ng/ml, p = 0.002) and similar to CAD patients (14 ± 5, ns). Despite this prothrombotic condition none of VA or NVA patients presented a myocardial infarction during a 9 year follow-up, an observation also reported in larger series. Conclusions: During a stable phase of their disease, patients with VA or NVA present a prothrombotic profile that might eventually contribute to occurrence of myocardial infarction. The rarity of these events, however, may suggests that ill defined factors would protect these patients from coronary plaque rupture/fissure
Metal content determination in biodiesel samples by microwave mineralization and ICP-AES
El trabajo comprende la puesta a punto de un método de digestión, mediante calentamiento de microondas, de muestras de biodiesel obtenidas mediante catálisis homogénea de aceites vegetales, para la determinación de 20 elementos mediante ICP-AES
Biodisponibilidad, acumulación y traslocación de arsénico y metales pesados en plantas autóctonas procedentes de suelos afectados por la actividad minera
Se han evaluado los factores de biodisponibilidad, acumulación y traslocación de arsénico y metales pesados, en plantas autóctonas procedentes de suelos contaminados por actividades mineras, mediante el análisis de dichas muestras por ICP-AES
Evaluation of the Chagas VirClia® and Chagas TESA VirClia® for the Diagnosis of Trypanosoma cruzi Infection
Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is an important problem of public health even in regions where it is not endemic. Spain ranks second worldwide in terms of imported cases of T. cruzi infection in the chronic phase. The diagnosis in this stage is made via the detection of antibodies against T. cruzi. Therefore, we aimed to evaluate the sensitivity and specificity of two fully automated chemiluminescence immunoassays, Chagas VirClia® (CHR), which uses a mixture of recombinant antigens, and Chagas TESA VirClia® (TESA), the first chemiluminescence assay based on excretion-secretion antigens of trypomastigotes, both designed in monotest format. A retrospective case-control study was performed using 105 well-characterized samples: 49 from patients with CD, 22 from uninfected individuals, and 32 from patients with other pathologies. Sensitivity was 98% for CHR and 92% for TESA. In contrast, the specificity in both was 100%. Cross-reactivity was observed in leishmaniasis (2/10). CHR meets the criteria to become a tool for serological screening, while TESA has the potential for confirmation and cross-reaction discrimination. The monotest format allows its application in laboratories with a small number of samples. The high specificity of both assays is useful in areas where leishmaniasis is endemic.This research was funded by Surveillance Program of Chagas disease in Spain of CNM, Instituto de Salud Carlos III (ISCIII), Madrid, Spain, and Mundo Sano Foundation-Spain.S
An Assessment of the Effect of Human Herpesvirus-6 Replication on Active Cytomegalovirus Infection after Allogeneic Stem Cell Transplantation
Human herpesvirus-6 (HHV-6) may enhance cytomegalovirus (CMV) replication in allogeneic stem cell transplant (allo-SCT) recipients either through direct or indirect mechanisms. Definitive evidence supporting this hypothesis are lacking. We investigated the effect of HHV-6 replication on active CMV infection in 68 allo-SCT recipients. Analysis of plasma HHV-6 and CMV DNAemia was performed by real-time PCR. Enumeration of pp65 and IE-1 CMV-specific IFNγ CD8+ and CD4+T cells was performed by intracellular cytokine staining. HHV-6 DNAemia occurred in 39.8% of patients, and was significantly associated with subsequent CMV DNAemia in univariate (P=.01), but not in multivariate analysis (P=.65). The peak of HHV-6 DNAemia was not predictive of the development of CMV DNAemia. Timing and kinetics of active CMV infection were comparable in patients either with or without a preceding episode of HHV-6 DNAemia. The occurrence of HHV-6 DNAemia had no impact on CMV-specific T cell immunity reconstitution early after transplant. The receipt of a graft from an HLA-mismatched donor was independently associated with HHV-6 (P=.009) and CMV reactivation (P=.04). The data favor the hypothesis that a state of severe immunosuppression leads to HHV-6 and CMV coactivation, but argue against a role of HHV-6 in predisposing to the development of CMV DNAemia or influencing the course of active CMV infection
XMM-Newton and Chandra observations of three X-ray faint early-type galaxies
We present XMM-Newton observations of three X-ray under-luminous elliptical
galaxies, NGC 3585, NGC 4494 and NGC 5322. All three galaxies have relatively
large optical luminosities (log LB=10.35-10.67 solar) but have X-ray
luminosities consistent with emission from discrete sources only. In
conjunction with a Chandra observation of NGC 3585, we analyse the XMM data and
show that the three galaxies are dominated by discrete source emission, but do
possess some X-ray emitting gas. The gas is at relatively low temperatures,
kT=0.25-0.44 keV. All three galaxies show evidence of recent dynamical
disturbance and formation through mergers, including kinematically distinct
cores, young stellar ages, and embedded stellar disks. This leads us to
conclude that the galaxies formed relatively recently and have yet to build up
large X-ray halos. They are likely to be in a developmental phase where the
X-ray gas has a very low density, making it undetectable outside the galaxy
core. However, if the gas is a product of stellar mass loss, as seems most
probable, we would expect to observe supersolar metal abundances. While
abundance is not well constrained by the data, we find best fit abundances <0.1
solar for single-temperature models, and it seems unlikely that we could
underestimate the metallicity by such a large factor.Comment: Accepted for publication in MNRAS, 12 pages, 8 postscript figure
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