Search Results (125)

The pollution caused by microplastics (MPs) in marine sediments has been a concern of many researchers thanks to these substances’ persistence and potential ecological effects. To our knowledge, this study represents the first comprehensive investigation of MP contamination in marine sediments collected from multiple regions of the Mediterranean Sea, encompassing a wide bathymetric range from coastal areas to deep-sea environments, down to approximately 4000 m water depth. Sediment samples were taken from several sites in the Mediterranean and the northern Aegean Sea. Thanks to microscopic analysis, fragments and filaments were the dominant MP forms; their color and size varied, and the most frequent particle colors were red, transparent and blue. FTIR spectroscopy revealed diverse types of polymers, including polystyrene (PS), propylene (PP), ethylene–vinylacetate (EVA), polyamide (PA), and Acrylonitrile Butadiene Styrene (ABS) polymer. The ^1-H NMR analyses confirmed the presence of PA, EVA, PP, polyethylene (PE), and PS, thereby supporting the FTIR results. This spatial variability in polymer composition probably reflects both regional anthropogenic inputs and hydrodynamic factors affecting sedimentary deposits. These results detail the complex and generalized nature of MP contamination in Mediterranean sediments and offer a basis from which to start assessing ecological risks and developing targeted mitigation strategies. Full article

For the impact-resistance evaluation of thermoplastics, the DuPont impact test is widely used to replicate multiaxial stress states inherent in actual product environments. However, conventional evaluation methods remain constrained by probabilistic pass/fail judgments or empirical calculations of absorbed energy. Consequently, quantifying the “material-specific fracture criterion,” which is indispensable for high-fidelity computer-aided engineering (CAE) analysis, persists as an important challenge. While our previous works established the derivation of CES from uniaxial tensile tests, the core originality of this study lies in extending this mechanical framework to the dynamic and multiaxial stress states of the DuPont impact test. By integrating a mathematical model with the probabilistic results of the staircase method, we enable for the first time the quantitative identification of material-specific fracture thresholds directly from standard drop-weight impact configurations. For this study, a novel mechanical model for deformation and fracture behavior in the DuPont impact test is constructed. Then a quantitative evaluation method is proposed for the “Critical Expansion Stress (CES),” a material-specific threshold triggering fracture under multiaxial stress. Specifically, using thermoplastic materials of five types and seven grades (including PP, POM, PS, ABS, and PC), the surface impact energy absorbed per unit volume was calculated via the DuPont impact test using the staircase method, accounting for size effects. Furthermore, microscopic parameters (shear modulus G and critical void volume fraction f0) were identified theoretically based on the mechanical properties obtained from short-beam shear tests. These parameters were integrated into a mathematical model to derive the CES. Comparing the derived CES with the true-stress-based uniaxial tensile strength, which incorporates the necking behavior during large deformations, revealed a distinct correlation governed by their mechanical relation (the 1:3 rule) based on the theoretical definition of hydrostatic stress. For the highly ductile polymer exhibiting significant strain hardening, this correlation holds universally when evaluated at the initial plastic flow stage prior to massive molecular orientation. The proposed method serves as a practical quantitative screening tool for evaluating the surface impact characteristics of plastic materials, providing an accessible framework for identifying material-specific fracture thresholds. Full article

The exposure of microplastics (MPs) to ultraviolet (UV) light in the environment can affect their flotation behavior and removal efficiency. This study investigated the effects of UVC irradiation on the physical and surface characteristics of polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polyethylene terephthalate (PET), and polyvinyl chloride (PVC), and evaluated their removal using agglomeration–micro-flotation. MPs were irradiated with UVC for 7 days, and they were characterized using particle size distribution analysis, CIE L*a*b* color analysis, and contact angle measurements. Flotation experiments were conducted using kerosene as a hydrophobic bridging liquid. The results showed that UVC irradiation induced polymer-dependent changes, including fragmentation, apparent shape-related changes, and redistribution behavior, resulting in changes in particle size distribution. Surface discoloration and reduced contact angle were also observed after UV exposure, suggesting photooxidative surface modification and increased surface hydrophilicity. These surface modifications reduced flotation performance at low kerosene dosages, particularly for PET and PVC. However, increasing kerosene dosage improved removal efficiency by enhancing agglomeration and particle–bubble attachment. The results indicated that agglomeration–micro-flotation is a promising approach for removing UV-aged MPs and provided insights into the influence of UV-induced surface modifications on flotation behavior. Full article

Peach (Prunus persica) fruit pigmentation is largely associated with anthocyanin accumulation, whereas colorless flavonols such as kaempferol glycosides may reflect alternative use of shared flavonoid precursors. To examine the relationship between anthocyanin and selected kaempferol glycoside accumulation, we analyzed 15 peach accessions classified by red, white, or yellow flesh pigmentation. Skin color was quantified using the a*/b* ratio, where a* represents redness/greenness and b* represents yellowness/blueness. Red-fleshed accessions showed higher skin a*/b* values and accumulated higher levels of total anthocyanins, particularly cyanidin-3-glucoside, than white and yellow accessions. In contrast, kaempferol-3-rhamnoside preferentially accumulated in white-fleshed accessions. Expression analysis of flavonoid pathway genes showed that dihydroflavonol 4-reductase (PpDFR) was more highly expressed in red accessions, whereas flavonol synthase (PpFLS) was more highly expressed in white accessions; chalcone synthase (PpCHS), flavanone 3-hydroxylase (PpF3H), flavonoid 3′-hydroxylase (PpF3′H), and anthocyanidin synthase (PpANS) showed no significant differences among color groups. Heterologous overexpression of PpF3′H in Arabidopsis thaliana, a well-characterized model plant for flavonoid biosynthesis, was associated with increased seed anthocyanin accumulation and a lower kaempferol-to-quercetin ratio, supporting its catalytic capacity to influence flavonoid composition in an exogenous system. Overall, these results indicate that differential anthocyanin and selected kaempferol glycoside accumulation in peach is associated with the relative expression patterns of branch-related flavonoid genes, particularly PpDFR and PpFLS. This study provides targeted metabolic and transcriptional evidence for understanding peach flesh and skin pigmentation and provides mechanistic insight into flavonoid branch competition linking gene expression patterns with metabolite allocation, and identifies candidate genes for improving fruit color and flavonoid-related nutritional quality. Full article

Inadequate domestic wastewater treatment remains a major environmental challenge due to the discharge of nitrogen compounds that originate primarily from human excreta, food residues, and household products, and are commonly present as ammonium and organic nitrogen. During biological processes, these compounds are converted to nitrite and nitrate, which are highly soluble and can easily migrate through soils, contaminating groundwater and posing risks to public health. Although Moving Bed Biofilm Reactors (MBBRs) are widely used for nitrogen removal, developing biocarriers with controllable geometry and optimized surface area for enhanced biofilm growth remains a challenge. This study aimed to design and fabricate gyroid-structured biocarriers using additive manufacturing (3D printing) from polylactic acid (PLA), acrylonitrile–butadiene–styrene (ABS), and polypropylene (PP), and to evaluate their performance in wastewater treatment for nitrogen removal. Bench-scale experiments showed significant chemical oxygen demand (COD) removal for all materials, with ABS and PP promoting the most stable biofilm formation. Pilot-scale tests with PP gyroid biocarriers achieved removal efficiencies of up to 87% for biochemical oxygen demand (BOD), 87% for ammonia, and 97% for nitrate. These results demonstrate that 3D-printed gyroid biocarriers provide a tunable geometry that enhances surface area and improves biological nitrogen removal in domestic wastewater treatment. Full article

Microwave-assisted depolymerization (MD) of heterogeneous postconsumer plastics was carried out in a quarter-scale reactor to evaluate product composition and the influence of feedstock type on oil quantity and quality. Various waste streams, including: PS, PP, ABS materials, keyboard housings, textile plastics, PCBs, and mixed electronic components, were processed in 3–6 kg batches using magnetron powers up to 2 × 1.55 kW. All experiments yielded a condensed liquid fraction, with color intensity correlating with aromatic content. FTIR spectroscopy showed that all oils consisted of hydrocarbon matrices dominated by aliphatic C-H stretching bands (2956–2850 cm⁻¹). Aromatic contributions varied significantly: PS produced oils rich in aromatic OOP C-H bands (900–650 cm⁻¹), PP yielded predominantly aliphatic oils with minor aromatic features, and ABS or electronics materials produced mixed aliphatic–aromatic profiles. Textile oils additionally exhibited carbonyl and O-H bands, indicating oxygenated decomposition products. Fractional distillation separated the oils into low-boiling aliphatic (<250 °C) and heavier aromatic (250–350 °C) fractions. These results suggest that MD reliably converts diverse plastic wastes into hydrocarbon oils whose spectroscopic characteristics reflect both feedstock composition and thermal pathways intrinsic to microwave heating. Full article

With the rapid development of cloud-based data sharing technologies, enterprises and organizations tend to outsource their local data to cloud servers. They adopt searchable encryption (SE) techniques to access and search encrypted data. However, most existing SE schemes use static ranking strategies based on query–index similarity. These strategies fail to capture users’ personalized retrieval preferences and often result in suboptimal search performance. In this article, we present a privacy-preserving data sharing framework with personalized encrypted retrieval (PP-PER) that combines SE technology with federated learning. PP-PER trains user interest models locally on user devices by utilizing historical query behavior. Only encrypted model parameters are uploaded for aggregation, which avoids the centralized collection of users’ private data. In addition, we design an attention-based user query update algorithm. The learned personalized features are integrated into the ciphertext query process. This design enables personalized ranking results and improves the user retrieval experience. Furthermore, PP-PER combines matrix factorization with ciphertext-policy attribute-based encryption (CP-ABE). This mechanism ensures secure document key distribution and supports fine-grained access control. Finally, we formalize the security model under a practical threat and leakage setting and provide a theoretical analysis of the proposed scheme. Experimental results on real-world datasets further validated its practicality and effectiveness. Full article

Injection-molding purges are heterogeneous, bulky residues whose uncertain composition and irregular geometry hinder direct reinsertion, making cold shredding costly and maintenance-intensive. This work develops a low-infrastructure solar-assisted pre-processing route using a PMMA Fresnel lens to induce controlled sub-onset softening and enable clean shear cutting without destructive thermal histories. The sub-onset softening is here defined into a viscoelastically active range (at or above T_g for the amorphous phase) while remaining below the melting onset (T_m, onset) and below the onset of thermal degradation (T_d, onset). The station was engineered via QFD and risk-oriented design tools, while a weighted Pugh matrix selected shear cutting over saw-based alternatives. A screening factorial DOE showed that lens height, angle, and their interaction significantly govern focal-spot diameter and receiver temperature, yielding linear relations for conservative set-point selection. Receiver benchmarking further indicated that copper reaches substantially higher temperatures than graphite under identical exposure conditions, supporting copper as the simplest, rapid-heating receiver. Under DOE-calibrated operation, tear-free shear cutting was achieved across representative purge families (PP–ABS, PC–ABS–PP, PA66, PA66-filler, and POM) without forced convection. From a recycling and waste-management perspective, the approach converts bulky purge scrap into mill-compatible feedstock with reduced mechanical resistance, lowering tool wear and fines generation, accelerating downsizing, and limiting stockpiling that elevates combustible-inventory fire risk. Overall, the proposed DOE-calibrated, operator-friendly framework improves recycling feasibility by enabling safer handling, more stable preprocessing throughput, and reduced reliance on disposal or long-term storage for heterogeneous industrial purges. Full article

Microplastic (MP) pollution poses a significant and emerging threat to global marine ecosystems; however, regional data for the Caribbean remain limited. This study presents a spatial and temporal characterization of MPs in surface and mid-waters of the Colombian Caribbean (Atlántico and Magdalena departments), which were analyzed as independent compartments due to methodological differences in sampling strategies. Sixteen sampling stations were established across two anthropogenic influence zones: Zone 1 (nearshore/bather zone) and Zone 2 (offshore). MPs were quantified and characterized according to shape, color, size, and polymer composition using attenuated total reflectance Fourier transform infrared microspectroscopy (µATR-FTIR) and multivariate techniques. MPs were detected in 100% of samples. Surface water MP abundance was higher in Magdalena (4.5 MPs m⁻³) than in Atlántico (1.7 MPs m⁻³). Mid-water MP concentrations reached maximum values during the high rainfall season in Atlántico, reflecting localized hydrological and anthropogenic influences rather than vertical gradients. Higher concentrations were generally observed in the nearshore Zone 1 compared to offshore Zone 2, although these differences were not consistently statistically significant. Fibers and fragments were the predominant shapes, and synthetic–natural polymer blends, polyethylene terephthalate (PET), polypropylene (PP), and polyacrylic acid (PAA) were the most prevalent. Generalized Additive Models (GAM) indicated that strong fluvial inputs and proximity to urban and riverine sources were factors driving MP distribution. Additionally, the detection of polymers reported in the literature as rare and high-risk, such as acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), styrene–ethylene–butylene–styrene (SEBS), and polyvinyl stearate (PVS), highlights the complexity of MP sources in the region. Overall, these results provide the first spatial and temporal characterization of MPs in the surface and mid-water of the Colombian Caribbean and identify critical contamination hotspots that warrant targeted mitigation strategies. Full article

This study investigates polypropylene (PP)–based biocomposites reinforced with systematically varied jute and glass fiber ratios as sustainable, lightweight alternatives for semi-structural automotive parts. Four formulations (J20/G0, J15/G5, J10/G10, J5/G15) with a constant 20 wt% total fiber were produced by injection molding and characterized through mechanical, thermal, and morphological analyses. Tensile, flexural, and Charpy impact tests showed progressive improvements in strength, stiffness, and energy absorption with increasing glass fiber content, while ductility was maintained or slightly enhanced. SEM revealed a transition from fiber pull-out in jute-rich systems to fiber rupture and stronger matrix adhesion in glass-rich hybrids. Thermal analyses confirmed the benefits of hybridization: heat deflection temperature increased from 75 °C (J20/G0) to 103 °C (J5/G15), and thermogravimetry indicated improved stability and higher char residue. DSC showed negligible changes in crystallization and melting, confirming that fiber partitioning does not significantly affect PP crystallinity. Benchmarking demonstrated mechanical and thermal performance comparable to acrylonitrile–butadiene–styrene (ABS) and acrylonitrile–styrene–acrylate (ASA), widely used in automotive components. Finally, successful molding of a prototype exterior mirror cap from J20/G0 validated industrial processability. These findings highlight jute–glass hybrid PP composites as promising, sustainable alternatives to conventional engineering plastics for automotive engineering applications. Full article

The Ddw1 dwarfing gene is pivotal for reducing plant height and improving lodging resistance in triticale, but its pleiotropic effects on yield components and heading date pose significant challenges for breeders. This study identifies the Growth-Regulating Factor 9-6A (GRF9-6A) gene that compensates for these drawbacks. Field trials across locations (Moscow, Krasnodar) and years (2018, 2019) confirmed the effect of Ddw1, reducing plant height by 26.1–30.1 cm (31.8–32.5%) and thousand-kernel weight (TKW) by 6.0–6.3 g (11.8–15.7%) while increasing the harvest index by up to 4.8 percentage points in three out of four environments, with its effect nullified under the heat stress of Krasnodar 2019. In a Ddw1 background, the GRF9-6Ab allele distinguished by a 12 bp deletion in its promoter compensated for yield losses by increasing grain weight per main spike by up to 0.34 g (19.2%) via boosts in grain number per spike (up to 11.6%) and TKW (up to 11.5%). This combination also elevated the harvest index by up to 4.0 pp and, critically, provided a key agronomic advantage by accelerating heading by 6.3–6.5 days (10.0–10.2%), thereby mitigating the Ddw1-associated developmental delay. Our results demonstrate that pyramiding Ddw1 with the GRF9-6Ab allele the development of semi-dwarf, high-yielding, and early-maturing triticale cultivars for food and forage. This breeding strategy, facilitated by a newly developed diagnostic marker for GRF9-6Ab, is particularly advantageous for cultivation in environments similar to the Central Non-Chernozem region. Full article

This article evaluates the influence of replicated natural structures, produced by micro-machining, on the wettability of plastic parts made from hydrophilic and hydrophobic polymer materials under various temperature and pressure conditions. Although many studies have focused on biomimetic surface design, the effect of specific processing parameters on the accurate replication of natural topologies and their resulting wettability has been only partially explored. This study addresses this gap by systematically analyzing the effect of melt temperature and packing pressure on the functional replication of micro-machined biomimetic structures. The research describes the design of hierarchical microstructures inspired by biomimetics and their fabrication by micro-milling on molded parts. Test samples were prepared from polypropylene (PP), acrylonitrile butadiene styrene (ABS), and polyamide 6.6 (PA 6.6) under different processing parameters, and wettability was assessed using contact angle (CA) measurements. The results confirmed significant variations in surface wettability depending on polymer type, melt temperature, and packing pressure. For the hydrophilic relief (Rock Moss), contact angles below 90° were obtained for all tested polymers, including PP, which decreased from 98.7° on a flat surface to 82.4° at 220 °C and 500 bar. In PA 6.6, a reduction of up to 12% in contact angle was observed compared to smooth samples at 310 °C and 500 bar. For hydrophobic reliefs (Three-part Hibiscus and Tricolor Pansy), contact angles exceeded 100–110°, with the highest value of 108.3 ± 1.6° for PP at 200 °C and 500 bar. Suitable combinations of melt temperature and packing pressure enabled accurate replication of microstructures while preserving their functional wettability, demonstrating the possibility of tuning surface properties through topological design. Full article

In injection molding, draft angle design plays a critical role in ensuring smooth de-molding and maintaining surface quality. With the growing emphasis on aesthetics and the increasing demand for the appearance of plastic products, the need for textured plastic components has continuously risen. The coupling between surface texture replication and dimensional accuracy has become an important indicator of product performance. However, systematic studies on the interaction between different polymer materials and draft angle design remain limited. This study aims to investigate the influence of draft angle variation on the surface texture quality and dimensional stability of injection-molded parts by comparing the differences between crystalline and amorphous thermoplastic materials, as well as between commodity and engineering plastics. Four representative polymers, namely polypropylene (PP), polyoxymethylene (POM), acrylonitrile-butadiene-styrene (ABS), and polycarbonate (PC), were selected to examine the impact of material characteristics on surface texture replication after molding. In addition, product geometries incorporating eight draft angles (0° to 3.5°) were designed. Surface texture replication was analyzed using scanning electron microscopy (SEM) and surface profilometry, while dimensional deformation was measured with a high-precision optical measuring instrument. The results show that draft angle variation has a limited influence on the overall trend of dimensional deformation, but it has a significant effect on the clarity of surface replication. Crystalline polymers exhibited generally higher surface roughness than amorphous polymers, and the distinction between commodity and engineering plastics, particularly those requiring higher processing temperatures, also led to higher roughness (PP > POM; ABS > PC). Dimensional deformation was more pronounced in crystalline polymers (POM > PP > ABS > PC). SEM observations further confirmed that higher roughness corresponded to clearer and more distinguishable texture patterns, whereas lower roughness resulted in blurred or indistinct textures. Full article

In this study, the thermal and structural behavior of battery module components produced from polymer-based composites was systematically evaluated using coupled Moldflow 2016 and ANSYS Fluent 2024 simulations. Three thermoplastics—metal-flake-reinforced PC+ABS (Polycarbonate/Acrylonitrile Butadiene Styrene), carbon-fiber-reinforced PEEK (Polyether Ether Ketone), and hybrid mineral-filled PP (Polypropylene)—were investigated as alternatives to conventional aluminum components. Moldflow simulations enabled the assessment of injection molding performance by determining injection pressure, volumetric shrinkage, warpage, residual stress, flow front temperature, and part weight. PEEK exhibited the best dimensional stability, with minimal warpage and shrinkage, while PP showed significant thermomechanical distortion, indicating poor resistance to thermally induced deformation. For thermal management, steady-state simulations were performed on a 1P3S pouch cell battery configuration using the NTGK/DCIR model under a constant heat load of 190 W. Material properties, including temperature-dependent thermal conductivity, density, and specific heat capacity, were defined based on validated databases. The results revealed that temperature distribution and Joule heat generation were strongly influenced by thermal conductivity. While aluminum exhibited the most favorable thermal dissipation, PC+ABS closely matched its electrical performance, with only a 1.3% lower average current magnitude. In contrast, PEEK and PP generated higher cell core temperatures (up to 20 K) due to limited heat conduction, although they had comparable current magnitudes imposed by the energy-conserving model. Overall, the findings indicate that reinforced thermoplastics, particularly PC+ABS, can serve as lightweight and cost-effective alternatives to aluminum in mid-range battery modules, providing similar electrical performance and thermal losses within acceptable limits. Full article

Background: Antimicrobial resistance (AMR) is a public health challenge, exacerbated by the inappropriate use of antibiotics (ABs) and the lack of standardized surveillance in healthcare settings. Objective: The Latin American PPS aimed to provide a standardized methodology for monitoring antibiotic use, gather data on antibiotic prescription practices, and support initiatives for antimicrobial stewardship (AMS). Methodology: Using a Spanish-adapted version of the WHO PPS methodology, a point prevalence survey (PPS) was conducted between 2022 and 2023 in 67 hospitals across five Latin American countries. Results: A total of 11,094 patients were surveyed, of which 47.9% received at least one AB; surgical and intensive care units displayed the highest prevalence. Most prescribed AB were third-generation cephalosporins (3GC) (22.0%), carbapenems (12.1%), glycopeptides (9.2%), and penicillin combinations (8.6%). A substantial use of agents classified under the WHO’s “Watch” group was found, with notable variances across countries. A multilevel logistic regression model identified that patient age, ICU admission, recent hospitalization, the presence of a catheter, and intubation were significantly associated with higher odds of AB use. In contrast, patients admitted to obstetric or pediatric wards had lower odds of receiving antibiotics. The model revealed considerable heterogeneity between countries, even after adjusting clinical and demographic factors. Conclusions: This study highlights AMS opportunities through targeted interventions, such as optimizing surgical prophylaxis, reducing the use of 3GC, carbapenems, and glycopeptides, and improving adherence to CPGs. These findings provide a comprehensive framework for policymakers and healthcare facilities to develop AMS strategies tailored to the Latin American context. Full article