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The Science of the Total Environment Jun 2024The settling behavior of microplastics (MPs) plays a pivotal role in their transport and fate in aquatic environments, but the dominant mechanisms and physics governing...
The settling behavior of microplastics (MPs) plays a pivotal role in their transport and fate in aquatic environments, but the dominant mechanisms and physics governing the settling of MPs in rivers remain poorly understood. To gain mechanistic insights into the velocity lag of MPs in an open-channel flume under different turbulent flow conditions, an experimental study was conducted using three types of MPs: polystyrene, cellulose acetate, and acrylic, of sphere-shaped particles with diameters ranging from 1 mm to 5 mm. A particle tracking technique was employed to record and analyze the MPs velocity within turbulent flows. The results showed a variation in the vertical settling velocity of MPs ω ranging from -26 % to +16 %, when compared to their counterparts in still water (ω). A new formula for the drag coefficient (C) of MP particles was developed by introducing the suspension number (u/ω). The developed C formula was used to calculate the resultant velocity lag V, with a mean relative error of 16 % compared with the measured values. Further, the study highlighted that the MPs with large Stokes numbers are mainly driven by their own inertia and turbulence has less influence on their settling behavior. This study is crucial for understanding the settling behavior of MPs in turbulent flows and developing their transport and fate models for MPs in riverine systems.
PubMed: 38925387
DOI: 10.1016/j.scitotenv.2024.174179 -
Journal of Colloid and Interface Science Jun 2024The petal effect is a well-known natural phenomenon in surface science and has served as inspiration for the creation of several materials with superhydrophobic...
HYPOTHESIS
The petal effect is a well-known natural phenomenon in surface science and has served as inspiration for the creation of several materials with superhydrophobic qualities and high adhesion. As surface roughness has a crucial role in these properties, being able to modulate it could help us design materials at will. Capillary penetration frustrates diffusion and promotes large contact angles as well as high adhesion.
EXPERIMENTS
Polystyrene surfaces were created using the spin-coating technique. By varying the polymer concentration, the surface roughness was modified. To determine the roughness parameters, atomic force microscopy was used. We recorded advancing and receding contact angles using water and glycerol as test liquids to study contact angle hysteresis, the work of adhesion and the apparent surface energy, which was determined with the Chibowski and Perea-Carpio method. For the purpose of elucidating the wetting states, captive bubble experiments were conducted.
FINDINGS
Using an easy method, we create polystyrene surfaces with both superhydrophobicity and strong adhesion, where the roughness area factor regulates wetting transitions from Cassie-Baxter to Wenzel. The receding contact angle suggests capillary penetration, which we demonstrate by captive bubble experiments. In addition, a link was found between the surface roughness and apparent surface energy.
PubMed: 38925063
DOI: 10.1016/j.jcis.2024.06.121 -
Macromolecular Rapid Communications Jun 2024Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), a conductive polymer, has gained popularity as the channel layer in organic electrochemical...
Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), a conductive polymer, has gained popularity as the channel layer in organic electrochemical transistors (OECTs) due to its high conductivity and straightforward processing. However, difficulties arise in controlling its conductivity through gate voltage, presenting a challenge. To address this issue, we employ aromatic amidine base, diazabicyclo[4.3.0]non-5-ene (DBN), to stabilize the doping state of the PEDOT chain through a reliable chemical de-doping process. Furthermore, the addition of the proton-penetrable material Nafion to the PEDOT:PSS channel layer induces phase separation between the substances. By utilizing a solution containing both PEDOT:PSS and Nafion as the channel layer of OECTs, we enhance the efficiency of ion movement into the channel from the electrolyte, resulting in improved OECT performance. The inclusion of Nafion in the OECTs' channel layer modifies ion movement dynamics, allowing for the adjustment of synaptic properties such as pulse-paired facilitation (PPF), memory level, short-term plasticity (STP), and long-term plasticity (LTP). This research aims to introduce new possibilities in the field of neuromorphic computing and contribute to biomimetic technology through the enhancement of electronic component performance This article is protected by copyright. All rights reserved.
PubMed: 38924243
DOI: 10.1002/marc.202400165 -
Environmental Science and Pollution... Jun 2024The growing anthropogenic contamination of natural water by microplastics (MPs) confirms the urgent need to preserve this precious resource. MPs are part of the group of...
The growing anthropogenic contamination of natural water by microplastics (MPs) confirms the urgent need to preserve this precious resource. MPs are part of the group of contaminants of emerging concern, and the occurrence studies in surface water and water for human consumption (WHC) are mandatory for environmental and human health risk assessment. This study aims to optimize and validate a Fourier transform infrared spectroscopy method coupled with optical microscopy (micro-FTIR) in transmission mode to monitor MPs in WHC. Water sample (250 mL; without sample pre-treatment) was filtered through 5 µm silicon filters. The infrared spectra identification was performed by OMNIC mathematical correlation, using various spectra libraries for polymers (including the in-house IR spectra library), a background reading on a clean silicon filter, and an aperture of 100 µm × 100 µm. The validated method showed good accuracy, with an average recovery for representative polymers of 91%, a relative standard deviation of 13%, and a reporting limit (RL) of 44 MPs/L. Sixty WHC samples from the Lisbon water supply system showed MPs ranging from 0 (< RL) to 934 MPs/L, with an average value of 309 MPs/L. The most representative polymers were polyethylene (PE, 76.8%), polyethylene terephthalate (PET, 6.9%), polypropylene (PP, 6%), polystyrene (PS, 4%), and polyamide (PA,4%). In terms of size, the microplastic particles had an average length and width of 76 µm and 39 µm, respectively.
PubMed: 38922468
DOI: 10.1007/s11356-024-33966-8 -
Environmental Health Perspectives Jun 2024Mice exposed orally to microspheres showed changes in lipid and other metabolic pathways, and the particles were detected in tissues throughout the body. Changes were...
Mice exposed orally to microspheres showed changes in lipid and other metabolic pathways, and the particles were detected in tissues throughout the body. Changes were greater after exposure to mixed microplastics compared with polystyrene alone.
Topics: Animals; Microplastics; Mice; Microspheres; Male; Polystyrenes; Administration, Oral
PubMed: 38922330
DOI: 10.1289/EHP15015 -
Toxins May 2024The aim of this study was to investigate the effects of aflatoxin B (AFB) on cholestasis in duck liver and its nutritional regulation. Three hundred sixty 1-day-old...
The aim of this study was to investigate the effects of aflatoxin B (AFB) on cholestasis in duck liver and its nutritional regulation. Three hundred sixty 1-day-old ducks were randomly divided into six groups and fed for 4 weeks. The control group was fed a basic diet, while the experimental group diet contained 90 μg/kg of AFB. Cholestyramine, atorvastatin calcium, taurine, and emodin were added to the diets of four experimental groups. The results show that in the AFB group, the growth properties, total bile acid (TBA) serum levels and total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and glutathione (GSH) liver levels decreased, while the malondialdehyde (MDA) and TBA liver levels increased ( < 0.05). Moreover, AFB caused cholestasis. Cholestyramine, atorvastatin calcium, taurine, and emodin could reduce the TBA serum and liver levels ( < 0.05), alleviating the symptoms of cholestasis. The qPCR results show that AFB upregulated () and () gene expression and downregulated () gene expression in the liver, and taurine and emodin downregulated and gene expression ( < 0.05). In summary, AFB negatively affects health and alters the expression of genes related to liver bile acid metabolism, leading to cholestasis. Cholestyramine, atorvastatin calcium, taurine, and emodin can alleviate AFB-induced cholestasis.
Topics: Animals; Aflatoxin B1; Ducks; Cholestasis; Liver; Bile Acids and Salts; Poultry Diseases; Cholestyramine Resin; Animal Feed
PubMed: 38922135
DOI: 10.3390/toxins16060239 -
Toxics Jun 2024Transgenerational nanoplastic toxicity could be detected in after exposure at the parental generation (P0-G); however, the underlying mechanisms remain largely unclear....
Transgenerational nanoplastic toxicity could be detected in after exposure at the parental generation (P0-G); however, the underlying mechanisms remain largely unclear. We aimed to examine the role of germline nuclear hormone receptors (NHRs) in controlling the transgenerational toxicity of polystyrene nanoparticles (PS-NPs) based on gene expression screening and functional analysis. Among germline NHR genes, , , and expressions were increased and expression was decreased by PS-NPs (1 and 10 μg/L). Transgenerational alterations in expressions of these four NHR genes were also induced by PS-NPs (1 and 10 μg/L). RNAi of , , and caused resistance, whereas RNAi of conferred susceptibility to transgenerational PS-NP toxicity. After PS-NP exposure, expressions of , , and encoding insulin ligands, encoding Ephrin ligand, and encoding Wnt ligand, as well as expressions of their receptor genes (, , and/or ), were dysregulated by the RNAi of , , , and . Therefore, alteration in certain germline NHRs could mediate the induction of transgenerational nanoplastic toxicity by affecting secreted ligands and their receptors in the offspring of exposed organisms.
PubMed: 38922100
DOI: 10.3390/toxics12060420 -
Nanomaterials (Basel, Switzerland) Jun 2024This study presents a comprehensive characterization of microplastics (MPs) and adsorbed/dissolved polycyclic aromatic hydrocarbons (PAHs) in the Arakawa River, the...
This study presents a comprehensive characterization of microplastics (MPs) and adsorbed/dissolved polycyclic aromatic hydrocarbons (PAHs) in the Arakawa River, the largest river system in Saitama and Tokyo, Japan. The MPs were sampled at various points along the river, revealing an average number density of 2.21 ± 1.48 pieces/m, with a predominant size range of 0.5-1 mm. Polymer analysis indicated that polyethylene (PE) comprised the highest proportion of MPs (55.9%), followed by polypropylene (PP) (22.4%) and polystyrene (PS) (21.7%). Seasonal fluctuations in MPs concentration were observed, with the highest values in winter and the lowest in summer. An analysis of adsorbed PAHs revealed a median partition coefficient (Kd) value of 3.58 × 10 L/kg for MPs, indicating their affinity for PAHs. Further PAHs analysis revealed that the PAHs with the highest mean values were bicyclic naphthalene, pyrene, and fluoranthene. A comparison with coastal MPs showed differences in PAH composition, with higher proportions of high-ring PAHs observed in coastal samples. The study also investigated the distribution of PAHs in the dissolved and suspended states in the river, finding that similar PAHs were distributed in both states, with the PAHs present in MPs being about 1/10,000 of those in the dissolved and suspended states. The study underscores the importance of the continued monitoring and management of MPs and associated pollutants in river ecosystems.
PubMed: 38921906
DOI: 10.3390/nano14121030 -
Journal of Xenobiotics Jun 2024Contamination with plastics of small dimensions (<1 µm) represents a health concern for many terrestrial and aquatic organisms. This study examined the use of...
Contamination with plastics of small dimensions (<1 µm) represents a health concern for many terrestrial and aquatic organisms. This study examined the use of plastic-binding peptides as a coating probe to detect various types of plastic using a plasmon nano-gold sensor. Plastic-binding peptides were selected for polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS) based on the reported literature. Using nAu with each of these peptides to test the target plastics revealed high signal, at 525/630 nm, suggesting that the target plastic limited HCl-induced nAu aggregation. Testing with other plastics revealed some lack of specificity but the signal was always lower than that of the target plastic. This suggests that these peptides, although reacting mainly with their target plastic, show partial reactivity with the other target plastics. By using a multiple regression model, the relative levels of a given plastic could be corrected by the presence of other plastics. This approach was tested in freshwater mussels caged for 3 months at sites suspected to release plastic materials: in rainfall overflow discharges, downstream a largely populated city, and in a municipal effluent dispersion plume. The data revealed that the digestive glands of the mussels contained higher levels of PP, PE, and PET plastic particles at the rainfall overflow and downstream city sites compared to the treated municipal effluent site. This corroborated earlier findings that wastewater treatment could remove nanoparticles, at least in part. A quick and inexpensive screening test for plastic nanoparticles in biological samples with plasmonic nAu-peptides is proposed.
PubMed: 38921649
DOI: 10.3390/jox14020040 -
Journal of Fungi (Basel, Switzerland) Jun 2024Plastic pollution of the ocean is a major environmental threat. In this context, a better understanding of the microorganisms able to colonize and potentially degrade...
Plastic pollution of the ocean is a major environmental threat. In this context, a better understanding of the microorganisms able to colonize and potentially degrade these pollutants is of interest. This study explores the colonization and biodegradation potential of fungal communities on foamed polystyrene and alternatives biodegradable plastics immersed in a marina environment over time, using the Brest marina (France) as a model site. The methodology involved a combination of high-throughput 18S rRNA gene amplicon sequencing to investigate fungal taxa associated with plastics compared to the surrounding seawater, and a culture-dependent approach to isolate environmentally relevant fungi to further assess their capabilities to utilize polymers as carbon sources. Metabarcoding results highlighted the significant diversity of fungal communities associated with both foamed polystyrene and biodegradable plastics, revealing a dynamic colonization process influenced by the type of polymer and immersion time. Notably, the research suggests a potential for certain fungal species to utilize polymers as a carbon source, emphasizing the need for further exploration of fungal biodegradation potential and mechanisms.
PubMed: 38921415
DOI: 10.3390/jof10060428