Search Results (31,130)

Microplastics (MPs), defined as synthetic polymer particles ranging from 1 μm to 5 mm, originate from various sources, including synthetic textiles, tire wear, degraded plastic waste, etc. Their small size and chemical stability make them challenging to remove, collect and degrade, posing significant adverse effects to both ecosystems and human health. While efforts to develop sustainable alternatives and removal methods are ongoing, effective solutions remain limited. Catalytic degradation and upcycling present a promising route to mitigate MP pollution by enabling efficient breakdown into less harmful molecules and potential upcycling into valuable products with lower energy requirements. This review provides a comprehensive overview of recent advances in catalyst design and development specifically for MP degradation, highlighting photochemical, thermal, biological, electrochemical, and hybrid approaches. Key challenges, reaction mechanisms, and future directions are discussed, offering a timely reference for researchers in this emerging field. Full article

Soil contamination by microplastics (MPs) is a global problem, exacerbated by the growing production of plastics and low levels of recycling. Considering that agricultural lands constitute a significant part of the land surface (37.7%), the study of the influence of MPs on the carbon cycle in such ecosystems is extremely important for understanding the global carbon balance. This work aims to develop a standardized protocol for determining the effects of microplastics (MPs) on the carbon cycle in agricultural soils. Differences in existing research protocols hinder comparability and limit conclusions about real-world impacts. A preliminary proposal for standardizing the protocol for the determination of MPs influence on the CO₂ and/or CH₄ emission in agricultural seeks to improve reproducibility and transparency in future studies. The protocol incorporates a wide variety of MPs characteristic in agricultural soils and allows experiments at realistic contamination levels, reflecting both current and projected future scenarios. Key recommendations include several points. Stringent contamination control during sample collection and preparation is of paramount importance. The selection of microplastic types and concentrations specific to agricultural environments is also recommended. Furthermore, maintaining consistent experiment durations is crucial, and the utilization of gas chromatography for analysis is highly desirable. Full article

In contrast to packaging, non-packaging plastics remain largely untargeted by EU regulations, despite their comprising over 60% of primary plastics in the EU 27 + 3 in 2022. This results in lower separate collection and recycling rates as well as fewer studies analysing recycling-relevant characteristics in non-packaging plastic waste (NPW), which are relevant to ensure the circularity and sustainable management of all plastics. This study presents a detailed characterisation of NPW found in mixed municipal solid waste and lightweight packaging waste on polymer and product levels, using the case study of Vienna, Austria. Results show that 4100 t/yr of polymers targeted for recycling, especially polypropylene, are currently discarded and lost in mixed MSW. A large share of NPW, however, exhibits recycling-hindering traits like multi-polymer objects or black colouring. While products made of high-quality food contact material were assessed to be ideal for separate collection to ensure closed-loop recycling, consideration should be given to collecting the majority of NPW via recycling centres to prevent contamination of target polymers with currently non-targeted other polymers. Design for recycling guidelines should also be introduced for non-packaging plastics, targeting separability, colouring and small-scale products. By doing so, a more sustainable management of NPW can be achieved. Full article

Campylobacter jejuni is an enteric pathogen and a major cause of foodborne illness worldwide. It has been shown that C. jejuni primarily utilizes amino acids as its preferred energy source, but its ability to utilize L-fucose can grant a competitive advantage during intestinal colonization. In C. jejuni, fucose utilization is encoded by a variable region named plasticity region 2 (PR2); however, the regulatory mechanism for the region remains unknown and is investigated in this study. Genomic sequence analysis revealed that immediately upstream of the fucose utilization operon is a putative IclR-type transcriptional regulator, cj0480c (named fucR here). To determine whether fucR regulates the expression of the fucose utilization operon, we generated a knock-out mutant of fucR. RT-PCR and microarray analysis found that all the genes in the operon were polycistronic and significantly upregulated in the fucR mutant compared with their expression in the wild-type strain. In the presence of fucose, expression of the fucose utilization genes was induced in the wild-type strain but no longer inducible in the fucR mutant, suggesting that FucR functions as a repressor for the fucose utilization operon. To determine whether FucR directly or indirectly regulates the fucose utilization operon, a 6xHis-tagged full-length FucR was produced in Escherichia coli, and the purified recombinant FucR was used in electrophoretic mobility shift assay, which demonstrated that FucR bound specifically to the promoter region of the fucose utilization operon. Together, these results indicate that the L-fucose utilization operon in C. jejuni is directly regulated by FucR, which functions as a transcriptional repressor and modulates the expression of the operon in response to fucose. Full article

The structural behavior of tile vaults remains challenging to evaluate accurately through numerical models, due to their geometry, the heterogeneity of its mechanical properties, and its boundary conditions. This study presents an experimental investigation carried out as part of a teaching innovation project aimed at deepening the understanding of masonry behavior through hands-on construction and collapse testing. Scaled vaults were built using traditional methods, employing thin bricks and fast-setting gypsum, materials typically selected for their accessibility and compatibility with heritage-inspired craftsmanship. The models were incrementally loaded until failure, enabling direct observation of collapse mechanisms. Plastic limit analysis was used to estimate structural capacity, with a focus on verifying the compatibility conditions of hinge formation. The vaults were documented using photogrammetric reconstruction (Structure-from-Motion) to generate accurate 3D models, and the evolution of collapse mechanisms was analyzed through digital motion tracking of observed hinges. Experimental loading reached values up to 4 kN/m² without collapse, confirming that even thin-tile vaults exhibit considerable reserve capacity. While these values should be understood as conservative lower-bound estimates due to the workshop conditions, results also highlight the significant influence of construction imperfections and boundary conditions. This work reinforces the educational value of physical experimentation and offers empirical insights into tile masonry behavior that cannot be captured through purely digital or parametric models. Full article

The manufacturing industry, in general, and the plastic industry, in particular, have been developing new materials and process methods that need a correct study and optimization. Nowadays, the main approach to optimize these processes is using numerical methods and, in the case of particulate materials, the Discrete Elements Method to estimate the particles interactions. But those mathematical models use some parameters that depend on the material and must be calibrated, thus requiring an important computational and experimental cost. In this study, we integrate different speed-up procedures and present a general calibration method of Low-Density Polyethylene particles, to obtain the calibrated solid density and Poisson’s ratio of the material, the restitution, static and rolling friction factors in the particle-to-particle and particle-to-wall interactions, and the contact model variables (damping factor, stiffness factor, and energy density). For this calibration, four different tests were carried out, both experimentally and with simulations, obtaining the bulk density, the repose and shear angles, and the dropped powder. All these response variables were compared between simulations and experimental tests, and using genetic algorithms, the input parameters (design variables) were calibrated after 85 iterations, obtaining a Mean Absolute Percentage Error of the response variables lower than 2% compared to the experimental results. Full article

Epithelial–mesenchymal transition (EMT) and inflammasome signalling are intercon-nected processes which underpin tumour progression, metastasis, and therapeutic re-sistance. Inflammasomes such as NLRP3 encourage pro-inflammatory states (IL-1β, IL-18, NF-κB) and the activation of signalling pathways like TGF-β that promote mes-enchymal traits crucial for EMT. EMT transcriptional programmes can then in turn modulate the inflammasome via NF-κB/TGF-β signalling, creating self-perpetuating mechanisms of cellular plasticity and dysregulated therapeutic response. We have re-viewed the mechanistic evidence for EMT–inflammasome crosstalk in cancer and discussed the potential therapeutic implications. The function of the EMT-inflammasome axis is clearly context-dependent, with the cancer type, stage, and the complexity of the tumour microenvironment heavily contributing. The crosstalk between EMT and the inflammasome is an overlooked mechanism of tumour evolution, and targeting inflammasomes like NLRP3, or their downstream signalling pathways, offers a promising therapeutic avenue, with the objective of inhibiting metastasis and overcoming drug resistance. Full article

The 60 kg/m U75V rail serves as the predominant rail type within China’s high-speed rail network. This study comprehensively evaluates the fatigue behavior of U75V rails through experimental investigations encompassing monotonic tensile testing, high-cycle fatigue characterization, and fatigue crack propagation analysis. All specimens were extracted from standardized 60 kg/m high-speed rail sections to ensure material consistency. Firstly, monotonic tensile tests were conducted to determine the fundamental mechanical properties of the U75V rail. Secondly, uniaxial tension–compression fatigue tests were conducted to establish the S-N and P-S-N relationships of the U75V rail. Lastly, fatigue crack propagation analysis was carried out on three compact tension specimens under three incremental loading forces. Monotonic tensile test results demonstrated full compliance of the material’s basic mechanical properties with Chinese national standards. Fatigue crack propagation results indicated that the crack growth rate of the U75V rail was not only related to the stress-intensity range ∆K but was also correlated with the loading force range ∆F due to a typical crack tip shielding effect, i.e., plasticity-induced crack closure effect. The derived fatigue performance parameters and crack growth mechanism provide essential inputs for predictive fatigue life modeling of high-speed rail infrastructure and development of refined finite element models for fatigue analysis. Full article

This study investigates the construction method of longitudinal displacement profiles (LDPs) for elastic–brittle–plastic tunnel-surrounding rock using numerical simulation. First, an axisymmetric numerical model of a circular tunnel is established based on the physical–mechanical parameters of granite at 630 m depth, with customized model parameters covering varying ratios of in situ stress to the global strength of the rock mass. Second, tunnel excavation is simulated using an elastic–brittle–plastic model, yielding radial displacement evolution data at the excavation boundary as a function of distance from the tunnel face. A quantitative relationship between these displacements and distances is derived, forming the proposed LDP construction method. Third, the calculated displacement evolution data (using the proposed method) show high consistency with both simulated and field-monitored data, validating the proposed method’s accuracy and reliability. Finally, a set of LDPs for elastic–brittle–plastic tunnel-surrounding rock is established, enabling the efficient determination of optimal support timing and streamlined tunnel support design. Full article

The recent increase in end-of-life (EoL) lithium-ion batteries (LiBs) has become a significant concern worldwide. Most studies in the literature have primarily focused on recovering cathode active metals from black mass (BM), whereas the separation of anode–cathode foils, plastics, and casing metals which are the essential components of LiBs has received relatively little attention. To reduce costs and maximize the recovery of valuable metals in subsequent hydrometallurgical or pyrometallurgical processes, EoL LiBs require appropriate pre-treatment. This study aims to scrape off the BM adhering to the electrode foils resulting from gradual crushing and subsequently separate the plastics and copper (Cu) from other metals through a two-step selective flotation process. The results demonstrated that plastics, due to their natural hydrophobicity, could be effectively removed using a frother, achieving more than 95% recovery with less than 5% metallic contamination. Following plastic flotation, Cu particles were floated in the presence of 3418A, yielding a Cu concentrate containing 65.13% Cu with a recovery rate of 96.4%. Additionally, the aluminum (Al) content in the non-floating material, remaining in the cell, increased to approximately 77%. Full article

The transition to a circular economy depends on the widespread adoption of sustainable products by consumers. However, the point-of-sale purchase decision is a complex process, influenced not only by ethical arguments but also by sensory cues. This study investigates how the aesthetics (visual design) and materiality (tactile sensation) of green products shape value perception and purchase intention. Using a qualitative methodology based on a focus group, the research directly compares consumer reactions to green products (e.g., a bamboo toothbrush) versus their conventional alternatives (e.g., plastic). Thematic analysis of the data reveals a fundamental dichotomy among consumers: while one segment associates high-tech aesthetics and perfect finishes with quality and hygiene, another segment values natural materials and their “imperfections” as signs of authenticity and responsibility. The results demonstrate that there is no single, universally accepted “sustainable aesthetic” and highlight the need for designers and marketers to align the visual and tactile language of products with the value system of the target consumer segment. The study provides a framework for understanding how design can act as either a barrier to or a catalyst for the adoption of sustainable products. Full article

This study investigates the enhancement of tribological performance in coarse-grained (CG) 42CrMo steel through the development of gradient-structured (GS) samples using double-sided symmetrical surface mechanical rolling treatment (D-SMRT). Dry reciprocating sliding wear tests are performed against a GCr15 steel counter ball to evaluate the influence of normal load on the wear resistance of CG and D-SMRT samples. Results demonstrate that D-SMRT significantly improves wear resistance under a 5 N load, attributed to the synergistic effects of surface strengthening and microstructure refinement. Characterization of worn surfaces via scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) confirms oxidative wear and abrasive wear as the dominant mechanisms at 5 N. With increasing load, wear transitions to abrasive and fatigue wear for the CG sample, while adhesive wear and plastic deformation dominate in the GS sample. This work concludes that D-SMRT technology effectively enhances the tribological properties of 42CrMo steel under normal loads below 10 N. Full article

Natural rock materials, containing micro-cracks and pore defects, significantly alter their mechanical behavior. This study investigated fracture interactions of red sandstone containing double close-round holes (diameter: 10 mm; bridge angle: 30°, 45°, 60°, 90°) using acoustic emission (AE) monitoring and the discrete element simulations method (DEM), which was a novel methodology for revealing dynamic failure mechanisms. The uniaxial compression tests showed that hole geometry critically controlled failure modes: specimens with 0° bridge exhibited elastic–brittle failure with intense AE energy releases and large fractures, while 45° arrangements displayed elastic–plastic behaviors with stable AE signal responses until collapse. The quantitative AE analysis revealed that the fracture-type coefficient k had a distinct temporal clustering characteristic, demonstrating the spatiotemporal synchronization of tensile and shear crack initiation and propagation. Furthermore, numerical simulations identified a critical stress redistribution phenomenon, that axial compressive force chains concentrated along the loading axis, forming continuous longitudinal compression zones, while radial tensile dispersion dominated hole peripheries. Crucially, specimens with 45° and 90° bridges induced prominently symmetric tensile fractures (85° to horizontal direction) and shear-dominated failure near junctions. These findings can advance damage prediction in discontinuous geological media and offer direct insights for optimizing excavation sequences and support design in cavern engineering. Full article

To combat the growing issue of petroleum plastic waste, alternative bio-based polymers are being developed. Many of these biopolymers are made from bio-derived materials, or are biodegradable, but the most promising polymers fall in both categories. Polyhydroxyalkanoates (PHAs) are one such class of polymers, and poly-3-hydroxybutyrate (P3HB), the most popular PHA, has shown great potential. This study utilized two types of cotton-derived glucose, alongside commercial glucose, as a feedstock for the biosynthesis of P3HB by Cupriavidus necator (also known as Ralstonia eutropha). The fermentation took place in a 2-L bioreactor, showing potential for scale-up. A single-solvent extraction method was created and utilized to reduce process complexity and chemical consumption of the polymer extraction. Both cotton-derived glucoses were shown to produce more P3HB than commercial glucose. The resulting P3HB samples were compared to each other and to the literature based on polymer yield and thermal characteristics. While all samples averaged a smaller yield than seen in the literature (indicating the need for optimization of the bacterial growth and metabolism with a growth curve in our future work), the cotton-derived glucose was shown to yield more P3HB than commercial glucose. Further, cotton-derived P3HB had very similar thermal properties to the commercial glucose-derived P3HB (and to values from the literature) with onset of thermal degradation ranging from 185 °C to 263 °C, cold crystallization temperatures ranging from 24 °C to 28 °C, and melting temperatures ranging from 147 °C to 151 °C. Lastly, all samples were shown to have a similar percentage crystallinity, ranging from 38% to 45%, which is slightly lower than that reported in the literature. P3HB made from cotton-derived glucose was shown to have potential as a scalable, sustainable alternative process. Full article

The autonomic nervous system (ANS) regulates internal organ function to maintain homeostasis. Dysautonomias are ANS disorders involving reduced or excessive sympathetic or parasympathetic activity and can be associated with metabolic syndrome and eating disorders such as binge eating disorder (BED). The ANS exhibits synaptic plasticity phenomena, including long-term potentiation (LTP) and neurotransmitter expression changes, which may influence autonomic function. BED is defined as recurrent, compulsive intake of large amounts of high-calorie food in a short time. Here, we examined dysautonomia in a rat BED model induced by cycles of food restriction and access to highly caloric food, and assessed whether exercise prevents these alterations. After confirming BED induction, we characterized LTP in the superior cervical ganglion (SCG) and analyzed acetylcholine (ACh) and GABA expression and their co-localization/segregation. BED rats exhibited impaired LTP and increased GABA expression. Voluntary aerobic exercise prevented BED onset and the associated changes in LTP and GABA. We propose that BED-associated dysautonomia proceeds at least in the ganglionic sympathetic cholinergic transmission, with reduced sympathetic activity. These results may contribute to a better understanding of the autonomic disorder associated with BED and support exercise as a protective intervention. Full article