There is a potential risk to increase the release of silver nanoparticles (Ag NPs) into the environment: For instance. in soils receiving sludge models estimate 0.007 mg Ag NPs kg−1 that will ...annually increase due to sludge or sludge incineration residues land-disposal. Thus, the concern about the hazards of nanosilver to soils and soil invertebrates is growing. Studies performed up to now have been focused in traditional endpoints, used limit range concentrations and employed different soil types that differ in physico-chemical characteristics. Presently, effects of Ag NPs have been measured at different levels of biological complexity in Eisenia fetida, exposed for 3 and 14 d to high but sublethal (50 mg Ag NPs kg−1) and close to modeled environmental concentrations (0.05 mg Ag NPs kg−1). Since characteristics of the exposure matrix may limit the response of the organisms to these concentrations, experiments were carried out in OECD and LUFA soils, the most used standard soils. High concentrations of Ag NPs increased catalase activity and DNA damage in OECD soils after 14 d while in LUFA 2.3 soils produced earlier effects (weight loss, decrease in cell viability and increase in catalase activity at day 3). At day 14, LUFA 2.3 (low clay and organic matter-OM-) could have provoked starvation of earthworms, masking Ag NPs toxicity. The concentration close to modeled environmental concentrations produced effects uniquely in LUFA 2.3 soil. Accurate physico-chemical characteristics of the standard soils are crucial to assess the toxicity exerted by Ag NPs in E. fetida since low clay and OM contents can be considered toxicity enhancers.
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•Ag NPs exerted toxicity at different levels of biological complexity in E. fetida.•Ag NPs caused increase in CAT activity and DNA damage in E. fetida in OECD soil (14 d).•High but sublethal concentrations exerted earlier toxic effects in LUFA 2.3 soil (3 d).•Close to modeled environmental concentrations only produce effects in LUFA 2.3 soils.•Low clay and OM contents enhance toxicity in LUFA 2.3 (3 d) and masked responses at day 14.
In composite reinforcement shaping, textile preform undergo biaxial tensile deformation, in plane shear deformation, transverse compaction and out-of-plane bending deformations. Bending deformations ...have been neglected in some simulation codes up to now, but taking into account them would give more accurate simulations of forming especially for stiff and thick textiles. Bending behaviour is specific because the reinforcements are structural parts and out of plane properties cannot be directly deduced from in-plane properties, like for continuous material. Because the standard tests are not adapted for stiff reinforcements with non linear behaviour a new flexometer using optical measurements has been developed to test such reinforcements. This new device enables to carry out a set of cantilever tests with different histories of load. A series of tests has been performed to validate the test method and to show the capacities of the new flexometer to identify non linear non elastic behaviour.
The current standard of care for locally advanced rectal cancer (RC) is neoadjuvant radio-chemotherapy (NRC) with 5-fluorouracil (5Fu) as the main drug, followed by surgery and adjuvant chemotherapy. ...While a group of patients will achieve a pathological complete response, a significant percentage will not respond to the treatment. The Unfolding Protein Response (UPR) pathway is generally activated in tumors and results in resistance to radio-chemotherapy. We previously showed that RHBDD2 gene is overexpressed in the advanced stages of colorectal cancer (CRC) and that it could modulate the UPR pathway. Moreover, RHBDD2 expression is induced by 5Fu. In this study, we demonstrate that the overexpression of RHBDD2 in CACO2 cell line confers resistance to 5Fu, favors cell migration, adhesion and proliferation and has a profound impact on the expression of both, the UPR genes BiP, PERK and CHOP, and on the cell adhesion genes FAK and PXN. We also determined that RHBDD2 binds to BiP protein, the master UPR regulator. Finally, we confirmed that a high expression of RHBDD2 in RC tumors after NRC treatment is associated with the development of local or distant metastases. The collected evidence positions RHBDD2 as a promising prognostic biomarker to predict the response to neoadjuvant therapy in patients with RC.
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•RHBDD2 modulates the expression of the UPR genes BiP, PERK and CHOP in CRC cells.•RHBDD2 binds to BIP, the master regulator to UPR pathway.•RHBDD2 expression affects the processes of adhesion, proliferation and migration related to cancer aggressiveness.•RHBDD2 overexpression confers CACO2 cells resistance to 5Fu treatment.•A high expression of RHBDD2 in rectal cancer after neoadjuvant radio-chemotherapy is associated with poor prognosis.
In the last years, applications for silver nanoparticles (Ag NPs) continue to increase together with the concerns about their potential input and hazards in aquatic ecosystems, where microalgae are ...key organisms. The aim of the present study was to assess the relative sensitivity of three marine microalgae species with differences in cell wall composition/structure exposed to Poly N-vinyl-2-pirrolidone/Polyethyleneimine (PVP/PEI) coated 5nm Ag NPs and uncoated 47nm Ag NP. As limited attention has been paid to the role of coating agents in NP toxicity, the effect of PVP/PEI alone was also evaluated. After 72h in artificial seawater, 47nm Ag NPs formed around 1400nm size aggregates while PVP/PEI coated 5nm Ag NPs reached around 90nm. Ag+ release in seawater was around 3% for 47nm Ag NPs and 30% for PVP/PEI coated 5nm Ag NPs. PVP/PEI coated 5nm Ag NP aggregates entrapped the algal cells in a network of heteroaggregates, while uncoated 47nm Ag NPs interacted to a lesser extent with algae. The concentration of PVP/PEI coated 5nm Ag NPs that exerted the median effect (EC50) on algae growth pointed out differences in algae sensitivity: T. suecica was about 10 times more sensitive than I. galbana and P. tricornutum. Further, the coating agent alone was as toxic to algae as PVP/PEI coated 5nm Ag NPs, suggesting that presence of the coating agent was the main driver of toxicity of coated NPs. Uncoated 47nm Ag NPs instead, showed similar toxicity towards algae although P. tricornutum was slightly less sensitive than T. suecica and I. galbana, which agrees with the presence of a resistant silicified cell wall in the diatom. The present work demonstrates differences in sensitivity of three marine microalgae, possibly related to their cell surface and size characteristics.
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•Effects of coated, uncoated Ag NPs and coating agent on microalgae were evaluated.•Coated 5 nm Ag NPs produced aggregates of smaller size and released 10 times more Ag ions than uncoated 47 nm Ag NPs.•Coated 5 nm Ag NPs were more toxic than uncoated 47 nm Ag NPs.•The coating agent alone was as toxic as coated 5 nm Ag NPs.•Tetraselmis suecica was about 10 times more sensitive than Isochrysis galbana and Phaeodactylum tricornutum.
Raw materials of mineral industries are mainly in the form of ore, which generate fine mineral particles during the extraction, comminution and transport which are primarily regarded as ...non-recyclable waste. The aim of this paper is to develop and characterize materials using recycled fine particles of bauxite sintered at high temperature at a laboratory scale for the calcium aluminate industry. To use these recycled materials as raw materials, the physico-chemical transformations during high-temperature processing are described. Phase transformations as a function of temperature were determined by XRD, and optical and electronic microscopies were utilized to observe microstructures. Materials with different particle size distributions showed different chemical reactivity as a function of particle size. The optimization of particle size distribution makes it possible to substitute synthetic bricks for bauxite ore using recycled fine particles of bauxite.
Classical numerical methods (F.E.M, theta-method, etc.) applied to simulate unsaturated impregnation in porous media require high computational cost, which becomes prohibitive when the impregnation ...is coupled with other physics such as chemical reactions. To overcome the computational difficulties, we propose to use a drastically different approach based on a new method we call Self-organized Gradient Percolation. The deduced algorithm aims to calculate the local saturation during non-reactive impregnation in unsaturated conditions in a more efficient way in terms of computational duration and precision than previous methods. The initialization of this algorithm is driven by an analytic solution of the homogeneous diffusion equation, obtained by convolving a Probability Density Function (PDF) with a suitably chosen smoothing function. Thus, we reproduce the evolution of the capillary pressure profile by means of the evolution of the standard deviation of the PDF. This algorithm is validated by comparing theoretical, experimental and numerical results.
This paper presents an experimental and thermodynamic contribution about the role of inorganics in ash-bed material interactions during thermal conversion of miscanthus in fluidized bed. The ...objectives are (1) to describe the transformation of inorganics at high temperature, (2) to reveal their role in the agglomeration and (3) to provide recommendations for miscanthus gasification in fluidized bed. The main ash forming elements in miscanthus are K, Si, Ca, Mg, P, S and Cl. The ashes are composed of silica, carbonates and salts. The carbonates and salts decompose and volatilise at 700 °C. At elevated temperature, the dominant solid phases are Ca and Mg silicates. The liquid phase is composed of SiO
2
, K
2
O, CaO, MgO regardless of the atmosphere. The accuracy of thermodynamic prediction tool is evaluated with the experimental results. The ash-bed interactions show that the wetting of bed material by molten ashes is one of the key parameters of the agglomeration. The adhesion of particles increases in the order of silica sand, olivine, calcined olivine. There is no significant difference in the agglomeration mechanism in oxidizing or reductive atmosphere. However, in reductive atmosphere, two immiscible liquid phases can occur. The parametric investigation shows that the operating temperature has a significant effect on the agglomeration ratio and the addition of kaolin or dolomite is the most effective tool to reduce agglomeration risks.
Bioavailability and toxicity of maltose-stabilised AgNPs of different sizes (20, 40 and 100 nm) in mussels were compared with bulk and aqueous forms of the metal through a two-tier experimental ...approach. In the first tier, mussels were exposed for 3 d to a range of concentrations (0.75, 75, 750 μg Ag/l) in the form of Ag20-Mal, Ag40-Mal, Ag100-Mal, bulk Ag and aqueous Ag (as AgNO
3
), as well as to the concentrations of maltose used in the formulation of NPs. Mortality, bioaccumulation, tissue and cell distribution and lysosomal responses were investigated. In the second tier, mussels were exposed for 21 d to Ag20-Mal, Ag100-Mal, bulk Ag and aqueous Ag at the lowest effective concentration selected after Tier 1 (0.75 μg Ag/l), biomarkers and toxicopathic effects were investigated. Aqueous Ag was lethal within 3 d at 75 μg Ag/l; Ag NPs or bulk Ag did not produce significant mortality at 750 μg Ag/l. Ag accumulation was limited and metallothionein gene transcription was not regulated although metal accumulation occurred in digestive, brown and stomach epithelial cells and in gut lumen after exposure to AgNPs and aqueous Ag starting at low concentrations after 1 d. Electrondense particles (<10 nm) in lysosomes and residual bodies after exposure to AgNPs contained Ag and S (X-ray). Intralysosomal metal accumulation and lysosomal membrane destabilisation were enhanced after exposure to all the forms of Ag and more marked after exposure to Ag20-Mal than to larger NPs. 21 d exposure to AgNPs provoked digestive cell loss and loss of digestive gland integrity, resulting in atrophy-necrosis in digestive alveoli and oedema/hyperplasia in gills (Ag NP), vacuolisation in digestive cells (aqueous Ag) and haemocyte infiltration of connective tissue (all treatments). Intralysosomal metal accumulation, lysosomal responses and toxicopathic effects are enhanced at decreasing sizes and appear to be caused by Ag
+
ions released from NPs, although the metal was not substantially accumulated.
•Hydrothermal gasification of Ulva macro algae is performed between 400 and 550°C.•Solid residues represent 7–18wt.% of the initial dry material and are a mixture of char and ash.•Gasification was ...performed in 7min and allows to obtain a H2, CO2 and CH4 mixture (>15mol.%).•The supercritical conversion was visualized with a Hydrothermal Diamond Anvil Cell.
Ulva (Ulva armoricana and Ulva rotundata) are macro algae which are responsible of environmental damages and are a cause of an eutrophication of the water in the French coast (Mediterranean sea, Brittany). In this study, Ulva were gasified in supercritical water in a batch reactor and in Hydrothermal Diamond Anvil Cell apparatus. Experimental conditions evolve between 400 and 550°C at around 250bar. Results show that a short time (7min) in supercritical condition is sufficient to obtain a significant conversion rate. H2 and CH4 concentrations exceed 15mol.% at high temperature (550°C) and high algae concentrations are not favorable for H2 production. The solid residue represents between 7 and 20wt.% of the initial dry material and is mainly constituted of carbon (20wt.%) and inorganic compounds: salts (KCl, NaCl), CaSO4, SiO2 and CaCO3. The very low dissolved organic carbon (DOC) values of the liquid residue (<0.4wt.%) confirm the high gasification rates. Thiophenes, pyridines, and pyrazines were detected in the liquid phase. Hydrothermal Diamond Anvil Cell (HDAC) experiments were performed to observe gasification stages at the supercritical state.
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