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Abstract: Bone tissue engineering consists of culturing osteoblastic cells onto synthetic three-dimensional (3D) porous scaffolds. The organization of bone cells into 3D scaffolds is crucial for ex vivo tissue formation. Diffusional rates of nutrients could be greatly improved by perfusing media through the 3D microporous scaffolds. However, bone cells cultured in vitro are responsive to a variety of different mechanical signals including fluid flow and shear stresses. In this work, we attempt to study osteoblastic cells behaviour cultured within microdevices allowing continuous and homogenous feeding of cells. We have fabricated polydimethylsiloxane PDMS microdevices with a 3D microstructured channel network. Mouse calvarial osteoblastic cells MC3T3-E1 were seeded at 2×106 cells/ml and cultured into the microdevices under flow rates of 0, 5, 35μl/min. Cells attached and proliferated well in the designed microdevices. Cell viability was found around 85% up to 1 to 2 weeks for shear stress value under 5mPa. The alkaline phosphatase (ALP) activity was enhanced 3- and 7.5-fold inside the microdevices under static and dynamic flow of 5μl/min as compared to flat static cultures in PDMS coated Petri dishes. Therefore, osteoblastic cells could be successfully cultured inside the microdevices under dynamic conditions and their ALP activity was enhanced. These results are promising for bone cell growth and differentiation as well as future tissue regeneration using larger 3D microfluidic microdevices. [Copyright &y& Elsevier]

Combining the MEMS technology and biology requirements for tissue engineering, the fabrication processes of microstructured chambers and microchannels made in biodegradable photosensitive polymers are presented. The fabrication processes, based on softlithography are very fast and flexible. Various single and multistepwise microstructures could be achieved using the biodegradable polymers. Microstructures down to 50 μm, which are suitable for liver reconstructs, could be fabricated. As the pCLLA acrylate photosensitive polymer has interesting property for implantable bioreactors, that is, its softness, we examined the ability of various mammalian cells to grow and spread on it. With Hep G2 cells, human umbilical blood vessel endothelial cells (HUVEC), 3T3-L1 mouse fibroblasts, static cultures could be successfully performed on single stepwise microstructures. Then, by using this photosensitive biodegradable polymer, a microstructure with simple fluidic channels is fabricated and a perfusion experiment could be carried out. Both cell cultures and perfusion experiments suggested the possibility to use the present photosensitive polymer as microfluidic supports for biodegradable bioreactors for implantation applications. [Copyright &y& Elsevier]

The data collected were: I) consumptions, expenditures and common indications IV/SC from 2014 to 2017 from AP-HP prescription software; II) AP-HP prescriptions carried out in retail pharmacies (PHMEV) for SC. In 2017 3 profiles were observed: 4/15 hospitals without rheumatology department which only use IV representing <0,1% of DDD; 8/15 hospitals with rheumatology departments which kept IV for hospital but also started PHMEV representing 74,9% of DDD; and 3/15 hospitals with rheumatology department which use both IV and SC at hospital also with PHMEV representing 25% of DDD. Different factors should be considered such as hospital policies encouraging ambulatory cares regarding day hospital capacities in every hospital and the imminent arrival of IV biosimilars. [Extracted from the article]

Abstract: A review of the published literature about foliar transfer radionuclides to cereal grains was carried out with a special interest for translocation factors. Translocation describes the distribution of radionuclides within the plant after foliar deposition and radionuclide absorption onto the surface of leaves. It mainly depends on elements and the plant growth stage. The collected data were derived from both in-field and greenhouse experiments. They were analysed in order to select those coming from a contamination simulating a sprinkling irrigation or a rain. The data set contains 307 values. For each radionuclide the translocation factor values were sorted according to 5 characteristic stages of the cereal vegetative cycle: leaf development-tillering, stem elongation, earing-flowering, grain growth and ripening. Wheat, barley and rye have been treated together, independently of rice. For mobile elements such as cesium, the translocation factor is maximum when the contamination occurred at the earing-flowering stage. For less mobile elements such as strontium this maximum occurred for a foliar contamination at the grain growth stage. This review enabled us to propose the most probable value as well as the range of variation of translocation factors for some radionuclides according to the cereal vegetative cycle. Moreover, from these results, a radionuclide classification is proposed according to three mobility groups. [Copyright &y& Elsevier]

This study aimed to (i) evaluate whether the K d value of selenium is dependent upon the soil microbial activity and (ii) define the limitation of the use of the K d concept to describe selenium behaviour in soils when assessing the long-term radiological waste disposal risk. K d coefficients, as well as information on selenite speciation in the soil-solution, were derived from short- and long-term batch experiments with a calcareous silty clay soil in various microbial states. Soil microbial activity induced (i) an increase of the K d value from 16lkg−1 in sterile conditions to 130lkg−1 when the soil was amended with glucose and nitrate, and (ii) changes in selenium speciation both in the solution (presence of seleno-species other than free Se(IV)) and in the solid phase (Se linked to microorganisms). Although the K d coefficient adequately reflects the initial fractionation between soil-solid and soil-solution, it does not allow for speciation and microbial processes, which could affect reversibility, mobility and the long-term accumulation and uptake into crops. [Copyright &y& Elsevier]

Gold mining operations near Yellowknife (Northwest Territories, Canada) released vast quantities of arsenic trioxide during the 1950s, which dispersed across the landscape. Contemporary measurements of arsenic concentrations in lake water and surficial sediment identify enrichment within a 30 km radius. However, paleolimnological studies have identified possible evidence of mining influence during the 1950s at a lake beyond this distance, suggesting a more expansive legacy footprint may exist. Here, we analyze spatiotemporal patterns of arsenic, antimony, and lead deposition from sediment cores at lakes located 10–40 km (near-field) and 50–80 km (far-field) from the mines along the prevailing northwesterly wind direction (NW) and 20–40 km to the northeast (NE) of the mines to improve characterization of the legacy footprint of emissions. We build upon previous findings to determine if: 1) there is evidence of mine-related pollutants beyond the well-established 30 km radius and 2) enrichment is greatest in the prevailing wind direction, as expected for aerial dispersion from a point source of emissions. Results demonstrate enrichment since the 1950s for arsenic and antimony at least as far as 80 km to the NW and 40 km to the NE, thus legacy deposition extended beyond the currently defined 30 km radius 'zone of immediate influence'. Concentrations, enrichment factors, and total excess inventories of arsenic and antimony decline with distance from the mines and are greater along the prevailing (NW) than orthogonal (NE) wind direction. Peak concentrations in uppermost sediment strata at near-field lakes in the prevailing wind direction suggest supply of arsenic and antimony remains high from legacy stores in the catchment and lake sediment profiles >60 years after emissions were released. Such lasting influence of legacy emissions likely is not limited to mines in the Yellowknife region, and paleolimnological approaches can effectively delineate zones of past and ongoing pollution from legacy sources elsewhere. [Display omitted] • We analyze metals in sediment cores to track dispersal of legacy mine emissions. • Enrichment of As and Sb evident beyond known 30-km radius pollution zone. • Distance from source and wind direction influenced contaminant dispersal. • Enriched surface sediments within 30 km suggest ongoing delivery of legacy metals. [ABSTRACT FROM AUTHOR]

In vitro metabolism of permethrin, a pyrethroid insecticide, was assessed in primary human hepatocytes. In vitro kinetic experiments were performed to estimate the Michaelis–Menten parameters and the clearances or formation rates of the permethrin isomers ( cis - and trans -) and three metabolites, cis- and trans -3-(2,2 dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid ( cis- and trans- DCCA) and 3-phenoxybenzoic acid (3-PBA). Non-specific binding and the activity of the enzymes involved in permethrin’s metabolism (cytochromes P450 and carboxylesterases) were quantified. Trans -permethrin was cleared more rapidly than cis -permethrin with a 2.6-factor (25.7 ± 0.6 and 10.1 ± 0.3 μL/min/10 6 cells respectively). A 3-factor was observed between the formation rates of DCCA and 3-PBA obtained from trans- and cis -permethrin. For both isomers, the rate of formation of DCCA was higher than the one of 3-PBA. The metabolism of the isomers in mixture was also quantified. The co-incubation of isomers at different ratios showed the low inhibitory potential of cis- and trans -permethrin on each other. The estimates of the clearances and the formation rates in the co-incubation condition did not differ from the estimates obtained with a separate incubation. These metabolic parameters may be integrated in physiologically based pharmacokinetic (PBPK) models to predict the fate of permethrin and metabolites in the human body. [ABSTRACT FROM AUTHOR]

Abstract: Apart from radiocaesium and radiostrontium, there have been few studies on the foliar transfer of radionuclides in plants. Consequently, specific translocation factor (f tr) values for 129I, 79Se and 36Cl are still missing from the IAEA reference databases. The translocation of short – lived isotopes, 125I and 75Se, and of 36Cl to wheat grain were measured under field conditions following acute and chronic wet foliar contamination at various plant growth stages in the absence of leaching caused by rain. The translocation factors ranged from 0.02% to 1.1% for 125I (a value similar to Sr), from 0.1% to 16.5% for 75Se, and from 1% to 14.9% for 36Cl. Both 36Cl and 75Se were as mobile as Cs. The phenomenological analysis showed that each element displayed a specific behavior. Iodide showed the lowest apparent mobility because of its preferential fixation in or on the leaves and a significant amount probably volatilized. Selenite internal transfer was significant and possibly utilized the sulphur metabolic pathway. However bio - methylation of selenite may have led to increased volatilization. Chloride was very mobile and quickly diffused throughout the plant. In addition, the analysis underlined the importance of plant growth responses to annual variations in weather conditions that can affect open field experiments because plant growth stage played a major role in f tr values dispersion. The chronic contamination results suggested that a series of acute contamination events had an additive effect on translocated elements. The highest translocation value obtained for an acute contamination event was shown to be a good conservative assessment of chronic contamination if data on chronic contamination translocation are lacking. The absence of rain leaching during the experiment meant that this investigation avoided potential radionuclide transfer by the roots, which also meant that radionuclide retention on or in the leaves was maximized. This study was therefore able to obtain accurate translocation factors, which are probably among the highest that could be recorded. [Copyright &y& Elsevier]

The topology of the potential energy surface associated with 1-pentene–Cu+ and 1-octene–Cu+ was investigated through the use of high-level density functional theory calculations. This theoretical survey, together with a combination of tandem mass spectrometry and isotopic labeling experiments carried out for 1-octene, confirm that the pseudo-insertion mechanism tentatively proposed by Fordham et al. [J. Mass Spectrom. 34 (1999) 1007], is the most favorable one. In this mechanism, attachment of the metal cation to the π-system forces a folding of the alkyl chain which favors the formation of an hexa-coordinated intermediate much more stable than the complexes formed along a typical dissociative attachment process. We have also shown that the main features of the pseudo-insertion mechanism do not change when the alkyl chain attached to the C&z.dbnd6;C double bond is much longer. Hence, we can safely conclude from our calculations and the experimental results obtained for 1-octene deuterated derivatives, that this mechanism would explain, in general, the specific reactivity of Cu+ with alkenes. We have also shown that the minor loss of H2 systematically observed in these gas-phase processes, would be related with the ability of Cu+ to yield strong agostic interactions either with the methylene groups or with the terminal methyl group of the alkyl chain. [Copyright &y& Elsevier]