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Benthic fluxes refer to the exchange rates of nutrients and other compounds between the water column and the sediment bed in aquatic ecosystems. Their quantification contributes to our understanding of aquatic ecosystem functioning. Near-bed hydrodynamics plays an important role at the sediment-water interface, especially in shallow lakes, but it is poorly considered by traditional measuring techniques of flux quantification, such as sediment incubations. Thus, alternative sampling techniques are needed to characterize key benthic fluxes under in-situ hydrodynamic conditions. This study aimed to evaluate the performance of two promising methods: relaxed eddy accumulation (REA) and mass transfer coefficient (MTC). We applied them in a hyper-eutrophic shallow lake to measure the fluxes of ammonium, phosphate, iron, and manganese ions. For the first time, REA revealed hourly nutrient flux variations, indicating a strong lake biogeochemical dynamics at short time-scales. Daily average fluxes are of similar orders of magnitude for REA and MTC for ammonium (24 and 42 mmol m2 d−1), manganese (1.0 and 0.8), and iron (0.8 and 0.7) ions. They are one order of magnitude higher than fluxes estimated from sediment incubations, due to the difficulty in reproducing in-situ oxygen and hydrodynamic conditions in the laboratory. Although the accuracy of both techniques needs to be improved, the results revealed their potential: REA follows the short-term biogeochemical dynamics of sediments, while MTC could be widely used for lake monitoring because of its simpler implementation. [Display omitted] • Quantifying benthic fluxes is crucial for understanding aquatic ecosystem functioning. • Turbulence above the sediment-water interface makes it challenging to measure them. • We assessed the performance of two hydrodynamic-dependent methods in a shallow lake. • Fluxes agreed for ammonium, manganese and iron ion fluxes. • One method (REA) revealed short-term dynamics while the other (MTC) proved simple. [ABSTRACT FROM AUTHOR]

Abstract It has been argued that concentration of major metallic ions such as Mg2+ and Ca2+ plays a role in determining the composition of the echinoderm skeleton. Consequently, in several studies Mg/Ca ratio from modern and fossil echinoderm ossicles was used as a proxy of secular Mg2+/Ca2+ changes of Phanerozoic seawater. However, although significant progress has been made in understanding biomineralization of echinoderms, it is still largely unknown what are the sources and physiological pathways of major ions that contribute to skeleton formation. Herein we tested the effects of modifications of ambient seawater Mg2+/Ca2+ ratio (which is typically ∼5) and Mg-enrichment of the diet on the Mg/Ca ratio in regenerating spines of sea urchin Paracentrotus lividus under experimental conditions. We found that sea urchins cultured in seawater with Mg2+/Ca2+ ratio decreased to ∼1.9 produced a skeleton with also decreased Mg/Ca ratio. However, the skeleton of specimens fed on a Mg-enriched diet showed significantly higher Mg/Ca ratio. This suggests that the seawater is an important but not the only source of ions that contributes to the Mg/Ca ratio of the skeleton. Consequently, the reliability of geochemical models that link directly seawater chemistry with the Mg/Ca ratio of the skeleton should be reevaluated. Highlights • Sea urchins fed on Mg-enriched diet display higher skeletal Mg content. • Seawater is not the only source of ions in echinoderm biomineralization. • Effect of diet should be taken into account when reconstructing seawater Mg/Ca ratio. [ABSTRACT FROM AUTHOR]

Local thermal environment has a strong influence on the physiology of marine ectotherms. This is particularly relevant for tropical organisms living close to their thermal optimum, well exemplified by the increasing frequency of bleaching occurrence in shallow-water corals. Mesophotic Coral Ecosystems (MCEs) were suggested as potential oases, especially when they are submitted to internal waves inducing short-term cooling events. Indeed, probability of bleaching occurrence in scleractinians was reported to decrease with depth in Mo'orea as temperature variability increases. However, ecophysiological data are currently lacking to understand the cause of lower susceptibility/increased plasticity of deeper corals. A growing interest has been devoted the last decade to MCEs, but our understanding of the physiological performance of benthic organisms living in this environment remains relatively unexplored. To tackle that question, we first compared the metabolic responses (dark respiration, net photosynthesis and photosynthetic efficiency) of the depth-generalist scleractinian Pachyseris speciosa from two heterogeneous thermal environment (25 and 85 m depths) to acute heat stress to determine if the local thermal environment could predict coral response to warming. Then, we tested the thermal performance of two sympatric species (the scleractinian P. speciosa and the antipatharian Stichopathes sp.) to determine if there are inter-species differences in performances in species experiencing identical levels of temperature variability, at mesophotic depths (85 m). Results revealed broader thermal performances in the mesophotic P. speciosa compared to mid-depth ones, and constrained performances in the mesophotic antipatharian compared to the scleractinian species. We hypothesize that the high fluctuations in temperature due to internal waves in deeper areas contribute to the broader thermal performances of mesophotic P. speciosa. However, the constrained performances of the mesophotic antipatharian compared to P. speciosa suggests that other processes than the symbiosis with zooxanthellae also influence thermal performances of these mesophotic organisms. Our results supported that Stichopathes sp. lives close to its thermal optimum, suggesting a (relatively) cold thermal specialist strategy. In this context, composition of MCEs in the future is unlikely to shift to antipatharian-dominated landscape and will remain coral-dominated landscape. [Display omitted] • P. speciosa has broader thermal performance at 85 than 25 m. • Thermal regime likely explains depth-specific thermal performance for P. speciosa. • At 85 m depth, thermal performance is narrower for Stichopathes sp. than for P. speciosa. • Cooling events generated by internal waves do not always improve thermotolerance. • Stichopathes sp. at 85 m lives close to its thermal optimum. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) or polylactide (PLA), a biodegradable polyester produced from renewable resources, is used for various applications (biomedical, packaging, textile fibers and technical items). Due to its inherent properties, PLA has a key-position in the market of biopolymers, being one of the most promising candidates for further developments. Unfortunately, PLA suffers from some shortcomings, whereas for the different applications specific end-use properties are required. Therefore, the addition of reinforcing fibers, micro- and/or nanofillers, and selected additives within PLA matrix is considered as a powerful method for obtaining specific end-use characteristics and major improvements of properties. This review highlights recent developments, current results and trends in the field of composites based on PLA. It presents the main advances in PLA properties and reports selected results in relation to the preparation and characterization of the most representative PLA composites. To illustrate the possibility to design the properties of composites, a section is devoted to the production and characterization of innovative PLA-based products filled with thermally-treated calcium sulfate, a by-product from the lactic acid production process. Moreover, are emphasized the last tendencies strongly evidenced in the case of PLA, i.e., the high interest to diversify its uses by moving from biomedical and packaging (biodegradation properties, “ disposables ”) to technical applications (“ durables ”). [ABSTRACT FROM AUTHOR]

The DBU·I 2 dual catalyst is shown to have a very high activity for the coupling reaction of CO 2 and various (bis)oxiranes. The cooperative work of both DBU and iodine is tolerant to water and allows performing the cyclo-addition of carbon dioxide in very mild conditions of pressure ( p CO 2 = 1 bar) and in total absence of organic solvent. [ABSTRACT FROM AUTHOR]

This study examined the physiological responses of the larval stages of Haliotis tuberculata , an economically important abalone, to combined temperature (17 °C and 19 °C) and pH (ambient pH and −0.3 units, i.e., +200% increase in seawater acidity) in a full factorial experiment. Tissue organogenesis, shell formation, and shell length significantly declined due to low pH. High temperature significantly increased the proportion of fully shelled larvae at 24 h post-fertilization (hpf), but increased the proportion of unshelled larvae at 72 hpf. Percentage of swimming larvae at 24 hpf, 72 hpf and 96 hpf significantly declined due to high temperature, but not because of low pH. Larval settlement increased under high temperature, but was not affected by low pH. Despite the fact that no interaction between temperature and pH was observed, the results provide additional evidence on the sensitivity of abalone larvae to both low pH and high temperature. This may have negative consequences for the persistence of abalone populations in natural and aquaculture environments in the near future. • Combined impacts of ocean acidification and warming on the larvae of the European abalone were investigated. • No interactive impact of temperature and pH was recorded. • Tissue organogenesis, shell formation, and shell length significantly declined due to low pH. • High temperature significantly increased the proportion of fully shelled larvae at 24 hpf, but increased the proportion of unshelled larvae at 72 hpf. • High temperature increased the settlement rate of the larvae. [ABSTRACT FROM AUTHOR]

Abstract: The effect of pH ranging from 8.0 to 6.8 (total scale – pHT) on fertilization, cleavage and larval development until pluteus stage was assessed in an intertidal temperate sea urchin. Gametes were obtained from adults collected in two contrasting tide pools, one showing a significant nocturnal pH decrease (lowest pHT =7.4) and another where pH was more stable (lowest pHT =7.8). The highest pHT at which significant effects on fertilization and cleavage were recorded was 7.6. On the contrary, larval development was only affected below pHT 7.4, a value equal or lower than that reported for several subtidal species. This suggests that sea urchins inhabiting stressful intertidal environments produce offspring that may better resist future ocean acidification. Moreover, at pHT 7.4, the fertilization rate of gametes whose progenitors came from the tide pool with higher pH decrease was significantly higher, indicating a possible acclimatization or adaptation of gametes to pH stress. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we evaluate the exploration of the Solar system by ad hoc wireless sensor networks (WSN), i.e., networks where all nodes (either moving or stationary) can both provide and relay data. The two aspects of self-organization and localization are the major challenges to achieve a reliable network for a variety of missions. We point out the diversity of environmental and operational constrains that WSN used for space exploration would face. We evaluate two groups of scenarios consisting in static or moving sensing nodes that can be either located on the ground or in the atmosphere of a Solar-system object. These scenarios enable collecting data simultaneously over a large surface or volume. We consider physical and chemical sensing of the atmosphere, surface and soil using such networks. Emerging technologies such as nodes localization techniques are reviewed. Finally, we compare the specific requirements of WSN for space exploration with those of WSN designed for terrestrial applications. [Copyright &y& Elsevier]

Abstract: The minimum and maximum actuation voltages in electrowetting actuated microsystems are investigated in this paper. The minimum actuation voltage corresponds to the electric potential required to obtain motion of a droplet between two electrodes. Below this threshold, a droplet cannot be displaced due to contact angle hysteresis. The maximum actuation voltage corresponds to the electric potential above which there is no more gain in capillary forces because of the saturation effect. Based on the calculation of the electrocapillary forces on a drop in an EWOD system, and taking into account the contact angle hysteresis, an analytical relation is derived for the minimum actuation potential. On the other hand, the Peykov–Quinn–Ralston–Sedev model produces an approximate value of the maximum actuation voltage. Thus, a range of actuation potentials can be predicted depending on the liquid of the droplet, the surrounding gas or fluid and the nature of the solid substrate. The results of the two models are favorably compared with experimental results obtained using different liquids and substrates. [Copyright &y& Elsevier]

Polyethylene-layered silicate nanocomposites were prepared by the in situ intercalative polymerization of ethylene by the so-called polymerization-filling technique and analyzed by transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Non-modified montmorillonite and hectorite were first treated by trimethylaluminum-depleted methylaluminoxane before being contacted by a Ti-based constrained geometry catalyst. The nanocomposite was formed by addition and polymerization of ethylene. In the absence of a chain transfer agent, ultra high molecular weight polyethylene was produced. The tensile properties of these nanocomposites were poor and essentially independent of the nature and content of the silicate. Upon hydrogen addition, the molecular weight of the polyethylene was decreased with parallel improvement of the tensile and shear moduli, in relation to the filler content. The exfoliation of the layered silicates was confirmed by XRD analysis and TEM observation. The mechanical kneading of the molten nanocomposites resulted in the partial collapse of the exfoliated structure driven by the thermodynamic stability of the layered filler. [Copyright &y& Elsevier]

• PLA and ABS were mixed by reactive extrusion with epoxidized cardanol compounds. • Epoxidized cardanol and its mixture with raw cardanol were tested. • Both approach led a substantial increase of the compatibility of PLA and ABS. • The mixture led a synergistic effect on the mechanical properties. • Impact strength increased of 172% and strain at break more than 1000% vs PLA. With the aim to reinforce polylactide (PLA) mechanical properties, poly(acrylonitrile-butadienestyrene) (ABS) is considered as a polymer of choice. However, PLA and ABS are immiscible, leading to blends with weak properties. Cardanol is a lipid phenolic known to compatibilize these two polymers thanks to its reaction with ABS, but does not react with PLA and restricts its use to the modification of ABS. In this work, we investigated the effect of cardanol-based compatibilizers able to react by reactive extrusion with both PLA and ABS. In a first approach, cardanol unsaturations were epoxidized (CardE), hoping to react with PLA, while cardanol phenolic group would react with ABS. This compatibilizer was efficient as attested by ABS nodules size reduction and dispersion within PLA, in addition to the merging of the relaxation temperatures of both polymers at 69.5 °C when 5 wt% CardE was used. In addition, it led to a substantial improvement of PLA/ABS impact strength and elongation at break. In a second approach, we used of a mixture of compatibilizers, containing raw and epoxidized cardanol, both of them reacting either with PLA or with ABS. Here, a clear synergistic effect was observed, as attested by the exceptional increases of both impact strength (+172% compared to neat PLA) and elongation at break (+1000% compared to neat PLA). We assumed modified chains of both PLA and ABS with cardanol derivatives during reactive extrusion would intersperse between PLA and ABS, reducing the interfacial tension and improving the interfacial adhesion, leading to the outstanding compatibilization of the blend. [ABSTRACT FROM AUTHOR]

Development of appropriate models, based on an in-depth understanding of the wash-off process, is essential to accurately estimating pollutant loads transported by stormwater, thereby minimizing environmental contamination. To this end, we developed an innovative rainfall simulator, which simulated an intense rainfall (120 mm/h) and permitted the acquisition of runoff samples as well as the in situ monitoring of continuous flow and turbidity dynamics. Relationships between deposited sediments and total suspended solids in simulated runoff were thus investigated on two different types of surfaces within the Paris region in terms of loads and particle size distribution. Results demonstrate the occurrence of first flush phenomenon on the sidewalks even under constant flow. Results also show that the highest fraction conveyed by runoff consisted of fine (< 16 μm) and medium-sized (< 100 μm) particles, whose detachment was more favorable from smooth surfaces than from rougher ones. In terms of stormwater quality modelling, results suggest that the integration of a wash-off fraction based on both particle size and rainfall intensity could be an entrance for a better prediction of stormwater pollution. [ABSTRACT FROM AUTHOR]

Halloysite nanotubes (HNT) and polylactide (PLA) were dry-mixed and melt-compounded to produce PLA nanocomposites with up to 12 wt-% nanofiller. The key characteristics of PLA-HNT nanocomposites were evidenced as follows: good nanofiller distribution and dispersion assessed by transmission electron microscopy (TEM), high tensile strength (values above 60 MPa) and mechanical rigidity, with Young's modulus increasing with HNT loading. The impact resistance of PLA is not decreased, whereas as it was revealed under dynamic solicitation (DMA), addition of HNT led to the notable enhancement of storage modulus. The degradation by photooxidation of PLA-HNT nanocomposites was compared to pristine PLA. The chemical modifications were evidenced by infrared (IR) and UV–visible spectroscopy, whereas from IR absorbance at 1845 cm -1 was determined the rate of degradation. Like in the case of other natural clays, HNT had a dramatic pro-degradant effect on the photooxidation of PLA, ascribed to the presence of chromophoric groups and/or iron impurities. Indeed, by comparing nanofillers of different purity, the photooxidation of PLA was found significantly reduced using HNT having about four times lower traces of iron. The choice of HNT of adequate purity or/and its purification is looked as powerful method to reduce the photooxidative degradation of PLA nanocomposites. [ABSTRACT FROM AUTHOR]

Shape-memory polymers (SMPs) as stimuli-responsive shape-changing polymers are of great interest for fundamental research and technological innovation. In this contribution, a brief review of the recent trends in the field of SMPs is presented with particular focus on their structure, shape-memory effects and working mechanism. A special attention is paid to smart multi-responsive and multi-functional SMP materials as emerging technological class. They are mainly described as shape-memory nanocomposites (SMCs) where the incorporation of functional (in)organic nanofillers in the SMP matrices is purposely carried out. Potential applications of the SMCs-based materials as medical and biomimetic devices, self-healing systems, self-deployable structures, actuators, sensors, etc. or their direct implementation in the industry are finally outlined. [ABSTRACT FROM AUTHOR]

Abstract: Polymer blends and alloys represent an interesting approach to implement bio-based poly(l-lactic acid) (PLLA) into high-value applications. Here, a re-evaluation of the miscibility extent between both biobased PLLA and petro-based poly(methyl methacrylate) (PMMA) is proposed in order to tune morphologies and properties of resulting blends upon either a solvent-casting method or a twin-screw extrusion. The solvent-casting process proved only able to produce immiscible blends with matrix–droplet or co-continuous morphologies in function of the blend composition and the immiscibility–miscibility transition is not observed for temperature lower than 250 °C. When melt-processed via extrusion technique, only miscible PLLA/PMMA blends were recovered all over the composition range, as observed by a single glass transition and a single α-relaxation transition at intermediate temperature between pure PLLA and pure PMMA as determined by DSC and DMTA, respectively. Miscibility was also observed at low shear rate with a phase-reversibility, demonstrating the absence of any reactions between PMMA and PLLA phases and the existence of a shear-sensitive clarity point. Homogenous and transparent PLLA/PMMA blends were easily produced with tunable thermomechanical and barrier properties against the blend composition. Glass transition temperature, α-relaxation temperature, thermal resistance and gas permeability were accurately controlled by the PMMA content, while maintaining impact strength and storage modulus in the same range than PLLA itself. [Copyright &y& Elsevier]

Abstract: This paper is the first report about the morphology of semi-crystalline poly(ε-caprolactone) (PCL) brushes studied by Atomic Force Microscopy (AFM) in tapping mode. This represents a convenient way to observe how the growth of a polymer proceeds from a thiol monolayer on gold substrate in terms of grafting density and thiol monolayer stability. The synthesis of semi-crystalline PCL brushes was carried out by Ring-Opening Polymerization (ROP) of ε-caprolactone (ε-CL) from hydroxyl end-group of thiol monolayer on gold surface as catalyzed with tin octoate (Sn(Oct)2) at 50°C. Addition of a sacrificial initiator was also attempted in order to get a finer control over PCL crystals. For a sake of comparison, triazabicyclo[4.4.0]dec-5-ene (TBD) was also investigated as another ROP catalyst active at ambient temperature. The composition and the morphology of resulting semi-crystalline PCL brushes were characterized using X-ray Photoelectron Spectroscopy (XPS) and AFM. In the case of Sn(Oct)2-promoted ROP of CL with or without free (sacrificial) initiator (i.e., benzyl alcohol), different types of morphologies were observed on the gold substrate, due to the thermal instability of thiol-gold bond under the experimental conditions. When TBD was used at ambient temperature, a regular and homogeneous crystalline morphology, i.e., compact PCL crystals, could be observed. [ABSTRACT FROM AUTHOR]

Abstract: New brush-like copolymers have been synthesized using functional polymethacrylate backbones bearing pendant sugars. Ring-opening polymerization (ROP) of l-lactide and ε-caprolactone have been performed using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) carbohydrate residues on the polymethacrylate chains. The latter have been first synthesized by copolymerization of three methacrylate monomers including methyl methacrylate (MMA), α-methoxy, ω-methacrylate poly(ethylene oxide) (MAPEO), and 1,2:3,4-di-O-isopropylidene-6-O-methacryloyl-d-galactopyranose (MAIGP) by atom transfer radical polymerization (ATRP) in toluene at 80°C using CuBr ligated with 1,1,4,7,10,10 hexamethyltriethylenetetramine (HMTETA) as catalytic complex. The protected sugars have been selectively deprotected using an aqueous solution of formic acid. The molecular characterization of those copolymers was performed by 1H-NMR spectroscopy, FT-IR spectroscopy and gel permeation chromatography (GPC) analysis. [ABSTRACT FROM AUTHOR]

In order to test the feasibility of transplantation of the whip black coral species Cirrhipathes anguina (Dana, 1846) from Madagascar, transplants were installed on cultivation tables in two sites (the North Pass and the Grande Vasque) characterized by distinct environmental conditions. Following transplantation, the transplants were followed for short-term (20 days) healing capacities and medium-term (200 days) mortality and growth rates. Results show a successful transplantation in both sites with 0% mortality (except in the form of missing fragments) and a certain growth over 200 days. Maximum growth rates were 3.4 cm/month and 2.0 cm/month in the North Pass and in the Grande Vasque, respectively. In addition, mean time to total healing was delayed in the Grande Vasque compared to the transplants in the North Pass (10 days). Differences between sites are likely to be related to differences in environmental parameters. Altogether, the promising results obtained with the easy protocol used in this study encourage the use of black coral transplants in further in situ experiments and restoration projects. • C. anguina can be easily grown from fragments on a table • Environmental conditions of transplantation and collection sites should be similar • Maximum apical growth rates for C. anguina were 3.4 cm/month • Naturally or externally caused breakage is part of the life-cycle of C. anguina [ABSTRACT FROM AUTHOR]

Biological effects of two structurally contrasting PCB congeners (coplanar 77 and non coplanar 153) were investigated by measuring the induction of CYP1A immunopositive protein (CYP1A IPP) in the pyloric caeca and the production of reactive oxygen species (ROS) by amoebocytes in the common sea star Asterias rubens. CYP1A IPP was quantified using a specially designed ELISA which uses competitive binding between sea stars and trout CYP1A IPPs. Only the coplanar congener had a significant effect on the two considered biological responses. Intensity of the effects was dose-dependent. However, the highest dose of PCB 77 induced a dramatic decrease of ROS production. It is concluded that coplanar PCBs straightforwardly affect key biological processes such as the immune system and mixed-function oxidase (MFO) system. [Copyright &y& Elsevier]

Abstract Road runoff is contaminated by various micropollutants and may be treated using low impact development techniques, such as stormwater biofilters. Better understanding the processes, such as filtration, sorption and leaching, which affect pollutants in these systems is essential to reliably predicting treatment performance and optimizing system design. Field data from an in situ monitoring campaign, wherein dissolved and particulate concentrations of a wide range of micropollutants (trace metals, polycyclic aromatic hydrocarbons, bisphenol-A, alkylphenols and phthalates) were characterized in untreated road runoff and biofilter outlets for 19 rain events, are used to explore transport and retention processes. Although retention of the particulate phase of pollutants was generally quite effective, unusually high particle concentrations were observed at biofilter outlets for three winter events. Particle characterization in road runoff and outlet waters revealed that this degraded performance was due to poor filtration rather than particle erosion, which was attributed to the relative abundance of small (<10 μm) particles during this period, along with possible preferential flows. Dissolved pollutants were less effectively removed in general. To better understand this behavior, field results were combined with laboratory sorption and leaching tests. Dissolved concentrations of trace metals were shown to be influenced by organic carbon; leaching from road-originated particles may also influence their transport. Removal of the dissolved phase of organic micropollutants was limited by the contamination of the filter media, either before installation or during the first period of operation, due to emissions from construction materials. Graphical abstract Unlabelled Image Highlights • Field data are used to consider processes affecting micropollutants in biofilters. • Outlet particles are usually a mixture of soil and road-originated particles. • Smaller particle sizes in road runoff in winter led to less effective filtration. • Dissolved trace metals do not appear to be in equilibrium with the soil. • Soil contamination limits the retention of dissolved organic micropollutants. [ABSTRACT FROM AUTHOR]

Highlights • Hydrogen bonds between acetate groups and −OH groups of SNCs surface are formed. • Good dispersion of SNCs into the EVA matrix thanks to the physical interactions. • Hydrogen bond interactions lead to improved mechanical and thermal properties. Abstract Starch nanocrystals (SNCs) were successfully synthesized by acid hydrolysis of waxy barley starch and were characterized by X-ray diffraction, scanning and transmission electron microscopy. Nanocomposites based on ethylene-co-vinyl acetate (EVA) and SNCs were produced by melt-processing using a microextruder. Interesting is to note that SNCs do not lose their crystalline nature during melt-processing. Moreover, the mechanical and thermal properties of the neat matrix were improved by the addition of SNCs thanks to the strong hydrogen bonding between the nanofillers surface and the acetate groups of the matrix. The introduction of 2 wt.% and 5 wt.% of SNCs into the matrix, lead to an increase of its elastic modulus of about 50% and 100%, respectively. Moreover, the addition of SNCs provoked an increase of the thermal stability of about 10 °C respect to the neat matrix. These results clearly revealed the possibility to introduce SNCs in a polymeric matrix by extrusion enabling to reach materials with enhanced mechanical and thermal properties due to beneficial hydrogen bonding between SNCs and EVA. [ABSTRACT FROM AUTHOR]

Abstract Sea urchins, ecologically important herbivores of shallow subtidal temperate reefs, are considered particularly threatened in a future ocean acidification scenario, since their carbonate structures (skeleton and grazing apparatus) are made up of the very soluble high-magnesium calcite, particularly sensitive to a decrease in pH. The biomechanical properties of their skeletal structures are of great importance for their individual fitness, because the skeleton provides the means for locomotion, grazing and protection from predators. Sea urchin skeleton is composed of discrete calcite plates attached to each other at sutures by organic ligaments. The present study addressed the fate of the sea urchin Paracentrotus lividus (Lamarck, 1816) skeleton in acidified oceans, taking into account the combined effect of reduced pH and macroalgal diet, with potential cascading consequences at the ecosystem level. A breaking test on individual plates of juvenile specimens fed different macroalgal diets has been performed, teasing apart plate strength and stiffness from general robustness. Results showed no direct short-term effect of a decrease in seawater pH nor of the macroalgal diet on single plate mechanical properties. Nevertheless, results from apical plates, the ones presumably formed during the experimental period, provided an indication of a possible diet-mediated response, with sea urchins fed the more calcified macroalga sustaining higher forces before breakage than the one fed the non-calcified algae. This, on the long term, may produce bottom-up effects on sea urchins, leading to potential shifts in the ecosystem equilibrium under an ocean acidified scenario. Highlights • Biomechanical properties of sea urchin test have a great importance in their individual fitness. • Combined effect of decreased pH and macroalgal diet highlights potential cascading effects. • No direct short-term effect of decreased pH and macroalgal diet on plate mechanical properties. • Longer term exposure needed to observe substantial differences on skeletal plate structure. [ABSTRACT FROM AUTHOR]

Abstract In this work, the thermal degradation and the disintegrability under composting conditions of melt-processed blends based on ethylene-vinyl acetate and thermoplastic starch, EVA/TPS, as well as their nanocomposites, reinforced with natural bentonite, were studied. A special emphasis was first put on the influence of starch on the morphology, thermomechanical properties and hydrophilicity of these blends before composting analysis. In fact, the materials were characterized in terms of morphological, mechanical, thermal and structural properties as well as wettability performance, obtaining information about the immiscibility of the blends and their compatibilization when natural bentonite is used. The thermal stability of starch was increased according with the EVA content in the blend, while the compatibility between both polymeric phases was increased by adding the nanoclays. Consequently, the disintegration under composting condition at laboratory scale level of the obtained materials was conducted and the thermal and chemical-structural properties as well as the surface microstructural changes of recovered samples at different stages of disintegration were studied. Disintegration tests showed that EVA/TPS blends and their nanocomposites presented positive interactions, which delay the disintegration of TPS matrix in compost, thus improving TPS stability. Moreover, blending biodegradable polymers such as TPS with non-biodegradable polymers like EVA leads to the increase of compostable polymer percentage in partially-degradable materials giving a possible solution for the end-life of these materials after their use. Highlights • The thermal, chemical-structural as well as surface microstructural changes of disintegrated sample were studied. • Natural bentonite increase the EVA/TPS compatibility delaying the disintegration of TPS matrix in compost. • Melt-blending TPS with EVA increase the stability of starch-based materials. [ABSTRACT FROM AUTHOR]