Uptake and absorption of fluoranthene from spiked microplastics into the digestive gland tissues of blue mussels, Mytilus edulis L.

The present work intended to investigate the fate of contaminant-loaded microplastics if ingested by benthic filter feeder Mytilus edulis under laboratory conditions. In the course of a 7-day experiment the mussels were exposed to PVC microplastics in a size range >40 mm, in doses of 2000 particles L_1 (11.56 mg L_1). Particles were either virgin or loaded with one of four different nominal concentrations of the polycyclic aromatic hydrocarbon (PAH) fluoranthene (500, 125, 31.25 and 7.8125 mg g_1). Verification of fluoranthene concentrations on the particles provided evidence of the high absorptive capacity of PVC for this PAH, indicating that comparable particles may serve as considerable accumulation sites for high concentrations of hydrophobic contaminants in the aquatic environment. Analysis of digestive gland tissues via polarised light microscopy revealed the occurrence of particles and particle aggregates within stomach and intestines of all mussels treated with microplastics, thus making the xenobiotic bioavailable. Results of contaminant analysis in mussel tissues via equilibrium sampling point to a considerable capability of microplastics for the accumulation of hydrophobic contaminants from the environment and their potential to act as vehicles for the transport of theses contaminants into organismal tissues. of fluoranthene concentrations on the particles provided evidence of the high absorptive capacity of PVC for this PAH, indicating that comparable particles may serve as considerable accumulation sites for high concentrations of hydrophobic contaminants in the aquatic environment. Analysis of digestive gland tissues via polarised light microscopy revealed the occurrence of particles and particle aggregates within stomach and intestines of all mussels treated with microplastics, thus making the xenobiotic bioavailable. Results of contaminant analysis in mussel tissues via equilibrium sampling point to a considerable capability of microplastics for the accumulation of hydrophobic contaminants from the environment and their potential to act as vehicles for the transport of theses contaminants into organismal tissues. © 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY licens

Uptake and absorption of fluoranthene from spiked microplastics into the digestive gland tissues of blue mussels, Mytilus edulis L.

The present work intended to investigate the fate of contaminant-loaded microplastics if ingested by benthic filter feeder Mytilus edulis under laboratory conditions. In the course of a 7-day experiment the mussels were exposed to PVC microplastics in a size range <40 mm, in doses of 2000 particles L-1 (11.56 mg L-1). Particles were either virgin or loaded with one of four different nominal concentrations of the polycyclic aromatic hydrocarbon (PAH) fluoranthene (500, 125, 31.25 and 7.8125 mg g-1). Verification of fluoranthene concentrations on the particles provided evidence of the high absorptive capacity of PVC for this PAH, indicating that comparable particles may serve as considerable accumulation sites for high concentrations of hydrophobic contaminants in the aquatic environment. Analysis of digestive gland tissues via polarised light microscopy revealed the occurrence of particles and particle aggregates within stomach and intestines of all mussels treated with microplastics, thus making the xenobiotic bioavailable. Results of contaminant analysis in mussel tissues via equilibrium sampling point to a considerable capability of microplastics for the accumulation of hydrophobic contaminants from the environment and their potential to act as vehicles for the transport of theses contaminants into organismal tissues

Influence of the type of post and core on in vitro marginal continuity, fracture resistance, and fracture mode of Lithia disilicate-based all-ceramic crowns

STATEMENT OF PROBLEM: The influence of different crown foundations on marginal seal and fracture resistance of ceramic crowns placed on endodontically treated teeth has not been clearly established. PURPOSE: The purpose of this study was to evaluate the marginal continuity and fracture behavior of high-strength all-ceramic crowns with different substructures in endodontically treated premolars. MATERIAL AND METHODS: Forty-eight human mandibular premolars were assigned to 6 groups, including a no-treatment group (UNTREATED) and a group for which the access cavity was restored with composite resin (Tetric Ceram) (COMP). In the remaining 4 groups, teeth were prepared to receive all-ceramic crowns with 0.8-mm-wide shoulders and axial dentin heights of 2 mm. No posts were used in the ENDOCROWN group. Glass fiber posts (FRC Postec) were used in group FRC-POST. Group ZRO-POST received zirconia ceramic posts (CosmoPost), and group GOLD-POST received cast gold posts (CM). Experimental lithia disilicate ceramic crowns were made and adhesively cemented (Variolink). All teeth were subjected to thermal cycling and mechanical loading (TCML) in a masticatory simulator (1,200,000 loads, 49 N, 1.7 Hz, 3000 temperature cycles of 5 degrees C-50 degrees C-5 degrees C). Marginal continuity was evaluated with scanning electron microscopy at x200. All specimens were loaded to failure in a universal testing machine at 0.5 mm/min after TCML. Data were analyzed using 1-way ANOVA and post hoc t tests with Bonferroni correction (alpha=.05). RESULTS: Initially, mean values (SD) between 72.4 (15.8)% (ENDOCROWN) and 94.8 (3)% (FRC-POST) for continuous margins were found. With TCML, marginal continuity decreased significantly only in FRC-POST, to 75.5 (8.4)%, and in ENDOCROWN, to 44.7 (14.5)%. Mechanical load testing measured mean loads to failure between 1092.4 (307.8) N (FRC-POST) and 1253.7 (226.5) N (ZRO-POST) without significant differences between groups. Deep root fractures were observed in half of the specimens, irrespective of their groups. CONCLUSIONS: Marginal continuity of the crowns studied was better and more stress resistant when posts and cores were included in the restoration of endodontically treated teeth with complete ceramic crowns. The placement of a post-and-core foundation did not influence the pattern of failure

Which transport policies increase physical activity of the whole of society? A systematic review

Purpose: There is strong evidence of the links between car-dependence and the physical inactivity pandemic. Physical inactivity accounts for 6–10% of major non-communicable diseases. Research  consistently shows that unlike passive transport, active transport is associated with higher total  daily physical activity (PA). While there are public policies that support PA in transport and, as a  result, overall PA levels, the specific quantitative effect of such policies on PA behaviour has not  been sufficiently investigated. The aim of this systematic review is to determine the level and type  of evidence for policies in the area of transport that contribute to higher PA levels of the whole of society. Methods: Six databases (MEDLINE (Ebsco), SportDiscus, Cinahl, Cochrane library, Web of Science,  and Scopus) were searched for key concepts of policy, transport, evaluation and PA. Methodological quality was assessed using standardized tools. The strength of the evidence of policy  impact was described based on pre-determined categories of positive, negative, inconclusive or  untested.  Results: 17 of 2549 studies were included in the data synthesis. The authors identified three main transport policy areas with 51 individual policy actions that had a direct or indirect effect on PA. These were: convenient transport infrastructure development, active travel promotion, and shift  of transport mode. More than half of the policy actions identified had a positive effect on PA.  Study quality ratings were moderate to good.  Conclusions: PA levels can be increased by implementing policies that provide convenient, safe,  and connected walking and cycling infrastructures, promote active travel and give strong support  to public transport. There is also clear evidence that active travel policies work best when  implemented in a comprehensive way. This may include infrastructure and facility improvements  as well as educational programmes to achieve substantial shifts towards active modes of travel. </p