385 research outputs found

    Hydroponics as a valid tool to assess arsenic availability in mine soils

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    The low solubility of As in mine soils limits its phytoavailability. This makes the extrapolation of data obtained under hydroponic conditions unrealistic because the concentration in nutrient solution frequently overexposes plants to this metalloid. This work evaluates whether As supply in hydroponics resembles, to some extent, the As phytoavailable fraction in soils and the implications for phytoremediation. Phytotoxicity of As, in terms of biomass production, chlorophyll levels, and As concentrations in plants, was estimated and compared in both soils and hydroponics. In order for hydroponic conditions to be compared to soil conditions, plant exposure levels were measured in both cultures. Hydroponic As concentration ranging from 2-8 μM equated to the same plant organ concentrations from soils with 700-3000 mg kg-1. Total and extractable As fractions exceeded those values, but As concentrations in pore water were bellow them. According to our results (i) hydroponics should include doses in the range 0-10 μM As to allow the extrapolation of the results to As-polluted soils, and (ii) phytoextraction of As in mining sites will be limited by low As phytoavailabilityThis study was supported by the Spanish Ministry of Education and Science, project CTM 2007-66401-CO2/TECNO, and by Comunidad de Madrid, project S-0505/AMB/029

    Co-application of activated carbon and compost to contaminated soils: toxic elements mobility and PAH degradation and availability

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    This work assesses the suitability of three commercial activated carbons (ACs) and their combination with olive mill waste compost (AC + C) as amendments for the remediation of two different contaminated soils. The treatments were applied to a mining soil, and their ability to immobilize trace elements was evaluated. Besides, the efficiency of the amendments to degrade and reduce the availability of polycyclic aromatic hydrocarbons (PAHs) was investigated in a soil from a wood creosote treatment plant. To this aim, trace elements mobility and PAH degradation and availability were evaluated. Ecotoxicological assays were performed to assess potential toxicity risks in the untreated and the amended soils. In the mining soil, the ACs were able to immobilize metals and As, but the AC + C treatments were more effective than AC. In the PAH-polluted soil, AC treatments promoted the degradation of high molecular weight PAH, but the AC + C amendments further enhanced the degradation of total PAH and reduced the availability of those with 3-rings. The ecotoxicological tests demonstrated an improvement of soil quality when AC and compost were applied together. In conclusion, the co-application of AC and compost reduces the mobility of potentially toxic elements in the polluted mine soil and enhances PAH degradation and reduces PAH availability in the creosote-contaminated soilThis work was fnancially supported by the Ministry of Economy and Competitiveness of Spain, projects CTM2013-47874-C2-R and CTM2013-48697-C2-

    Translocated LPS Might Cause Endotoxin Tolerance in Circulating Monocytes of Cystic Fibrosis Patients

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    Cystic Fibrosis (CF) is an inherited pleiotropic disease that results from abnormalities in the gene codes of a chloride channel. The lungs of CF patients are chronically infected by several pathogens but bacteraemia have rarely been reported in this pathology. Besides that, circulating monocytes in CF patients exhibit a patent Endotoxin Tolerance (ET) state since they show a significant reduction of the inflammatory response to bacterial stimulus. Despite a previous description of this phenomenon, the direct cause of ET in CF patients remains unknown. In this study we have researched the possible role of microbial/endotoxin translocation from a localized infection to the bloodstream as a potential cause of ET induction in CF patients. Plasma analysis of fourteen CF patients revealed high levels of LPS compared to healthy volunteers and patients who suffer from Chronic Obstructive Pulmonary Disease. Experiments in vitro showed that endotoxin concentrations found in plasma of CF patients were enough to induce an ET phenotype in monocytes from healthy controls. In agreement with clinical data, we failed to detect bacterial DNA in CF plasma. Our results suggest that soluble endotoxin present in bloodstream of CF patients causes endotoxin tolerance in their circulating monocytes

    Energy Dissipating Devices in Falling Rock Protection Barriers

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    Rockfall is a phenomenon which, when uncontrolled, may cause extensive material damage and personal injury. One of the structures used to avoid accidents caused by debris flows or rockfalls is flexible barriers. The energy dissipating devices which absorb the energy generated by rock impact and reduce the mechanical stresses in the rest of the elements of the structure are an essential part of these kinds of structures. This document proposes an overview of the performance of energy dissipating devices, as well as of the role that they fulfil in the barrier. Furthermore, a compilation and a description of the dissipating elements found in the literature are proposed. Additionally, an analysis has been performed of the aspects taken into account in the design, such as experimental (quasi-static and dynamic) tests observing the variation of the behaviour curve depending on the test speed and numerical simulations by means of several finite element software packages

    DNA aneuploidy as a topographic malignant transformation pattern in a pleomorphic adenoma of long-term evolution: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>We present a case of long-term evolution of a submandibular pleomorphic adenoma. There is little information about topographic malignant transformation patterns of pleomorphic adenomas.</p> <p>Case presentation</p> <p>We extensively analyze a giant submandibular mixed tumor of 25-year evolution in a 57-year-old Caucasian woman. Deoxyribonucleic acid ploidy was evaluated in different superficial and deep areas using flow cytometry analysis and correlated with pathological and immunohistochemical characteristics. Superficial areas exhibited a typical histological pleomorphic adenoma pattern and were deoxyribonucleic acid diploid. Deep samples showed deoxyribonucleic acid aneuploidy, atypical histological benign features and expression of markers involved at an early-stage of malignant transformation, such as tumor protein 53 and antigen Ki67.</p> <p>Conclusion</p> <p>These findings revealed that deep tumor compartments may be involved in the initial stages of malignant transformation. Deoxyribonucleic acid ploidy analysis may provide an additional diagnosis tool and indicate 'uncertain' areas that require careful study to avoid diagnostic errors. Larger studies are needed to confirm our results and to evaluate the usefulness of the technique.</p

    Metallothionein in human oesophagus, Barrett's epithelium and adenocarcinoma

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    The potential of the metal-binding protein, metallothionein, in assessing the progression of normal oesophagus through Barrett's to adenocarcinoma was investigated. Metallothionein was quantitatively determined in resected tissues from patients undergoing oesophagectomy for high grade dysplasia/adenocarcinoma and in biopsies from patients with Barrett's syndrome. In 10 cancer patients, metallothionein concentrations in adenocarcinoma were not significantly different from normal oesophagus, although six had elevated metallothionein concentrations in the metaplastic tissue bordering the adenocarcinoma. In 17 out of 20 non-cancer patients with Barrett's epithelium, metallothionein was significantly increased by 108% (P<0.004). There was no association between the metallothionein levels in Barrett's epithelium and the presence of inflammatory cells, metaplasia or dysplasia. Metallothionein is a marker of progression from normal to Barrett's epithelium but is not increased in oesophageal adenocarcinoma
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