Plasticizing Effect Research Articles

Effects of residual elements on the microstructure and mechanical properties of a Q&P steel

Producing steel requires large amounts of energy to convert iron ores into steel, which often comes from fossil fuels, leading to carbon emissions and other pollutants. Increasing scrap usage emerges as one of the most effective strategies for addressing these issues. However, typical residual elements (Cu, As, Sn, Sb, Bi, etc.) inherited from scrap could significantly influence the mechanical properties of steel. In this work, we investigate the effects of residual elements on the microstructure evolution and mechanical properties of a quenching and partitioning (Q&P) steel by comparing a commercial QP1180 steel (referred to as QP) to the one containing typical residual elements (Cu+As+Sn+Sb+Bi<0.3wt%) (referred to as QP-R). The results demonstrate that in comparison with the QP steel, the residual elements significantly refine the prior austenite grain (9.7μm vs. 14.6μm) due to their strong solute drag effect, leading to a higher volume fraction (13.0% vs. 11.8%), a smaller size (473 nm vs. 790 nm) and a higher average carbon content (1.26 wt% vs. 0.99 wt%) of retained austenite in the QP-R steel. As a result, the QP-R steel exhibits a sustained transformation-induced plasticity (TRIP) effect, leading to an enhanced strain hardening effect and a simultaneous improvement of strength and ductility. Grain boundary segregation of residual elements was not observed at prior austenite grain boundaries in the QP-R steel, primarily due to continuous interface migration during austenitization. This study demonstrates that the residual elements with concentrations comparable to that in scrap result in significant microstructural refinement, causing retained austenite with relatively higher stability and thus offering promising mechanical properties and potential applications.

Neuroinflammation inhibition and neuroprotective effects of purpurin, a potential anti-AD compound, screened via network proximity and gene enrichment analyses.

Alzheimer's disease (AD) is a complex neurodegenerative disease without any effective preventive or therapeutic drugs. Natural products with stable structures and pharmacological characteristics are valuable sources for the development of novel drugs for many complex diseases. This study aimed to discover potential natural compounds for the treatment of AD using new technologies and methods and explore the efficacy and mechanism of candidate compounds. AD-related large-scale genetic datasets were collated to construct disease-PPIs and natural products were collected from six databases to construct compound-protein interactions (CPIs). Potential relationships between natural compounds and AD were predicted via network proximity and gene enrichment analyses. Then, five AD-related cell models and d-galactose-induced aging rat model were established to evaluate the neuroprotective effects of candidate compounds in vitro and in vivo. We identified that 267 natural compounds were predicted to have close connections with AD and 19 compounds could exert protective effect in at least one cell model. Notably, purpurin exerted protective effect in three cell models and significantly improved the cognitive learning and memory functions, reduced the oxidative stress injuries and neuroinflammation, and enhanced the synaptic plasticity and neurotrophic effect in the brain of d-galactose-treated rats. In this study, AD-related natural compounds were identified via network proximity and gene enrichment analyses. In vivo and in vitro experiments revealed the therapeutic potential of purpurin for AD treatment, laying the foundation for further in-depth research and providing valuable information for the development of novel anti-AD drugs.

Harnessing the Plastic-degrading Potential of Pseudomonas Species for Environmental Sustainability

Abstract The prevalent utilization of synthetic plastics in contemporary society has made them indispensable. Nonetheless, the enduring predicament of plastic waste presents challenges to environmental sustainability and effective waste management. Plastic pollution can disrupt habitats and natural processes, diminishing the ecosystem’s resilience to climate change and directly impacting the livelihoods, food production capabilities, and social well-being of people. Moreover, plastic recycling itself can rise the production of polluting microplastic that find their way into water sources or air. In to address the environmental predicaments associated with plastics, it is imperative to examine the intricate interplay between microbes and polymers. Understanding this dynamic relationship is important as we strive to develop effective solutions and mitigate the adverse effects of plastic on our environment. Bacteria evolved strategies to survive and degrade plastics in contaminated environments. In this study, we focused on the ability of Pseudomonas species to degrade different sets of synthetic plastics including Low-Density polyethylene (LDPE), High-density polyethylene (HDPE), polyvinyl and polystyrene. Then a simulation study using kinetic models was conducted to determine optimum parameters for degradation ability. Our results indicate four different Pseudomonas strains P. aeruginosa strains, P. boreopolis and P. dehiensis two strains of which were able to grow in minimum media containing the different plastics as the only carbon sources reflecting their capacities to degrade these complexes polymers. Kinetic modeling for microbial growth of P. aeruginosa using batch and feed batch demonstrated that the feed batch fermentation procedure has the potential to produce Pseudomonas biomass on a larger scale, with a production of 250.7481 g/l after 72 hours. These results enhance their applicability in industrial settings particularly in bioremediation field. These findings highlight the important uses of bacterial strain of Pseudomonas as a promising strategy to depolymerize complex plastics into monomers for recycling or mineralize them into new biodegradable biomass.

Design of tri-phase lamellar architectures for enhanced ductility in ultra-strong steel

Achieving exceptional ductility in ultra-high strength steels has long been a formidable challenge, particularly when the yield strength reaches 2.0 GPa. In this study, we have designed an innovative tri-phase lamellar microstructure in medium Mn steel that successfully achieves both an ultrahigh yield strength of approximately 2.0 GPa and an impressive uniform elongation ranging from 22.5 % to 24.5 %. The ultra-high yield strength of this steel is primarily due to the ultrafine lamellar grain with high-density dislocations and HDI strengthening resulting from meticulously designed tri-phase lamellae. The remarkable ductility is attributed to the synergistic action of multiple plasticity mechanisms. The inherently excellent plasticity of the lamellar ferrite, in coordination with the lamellar martensite, generates significant HDI hardening, thereby suppressing the onset of necking in the early stages of deformation. During the mid-stage of deformation, high strain activates the transformation-induced plasticity effect in the highly stable austenite, which remains stable due to substantial HDI hardening and effectively mitigates strain localization. In the later stages of deformation, delamination cracking relieves stress accumulation at the interfaces, delaying material failure. These mechanisms elevate yield strength and uniform elongation product to 47.3 GPa·%, showcasing the tri-phase lamellar structure’s potential for ultrahigh-strength, high-ductility steels.

Production of Bio-plasticized Polyvinyl Chloride (PVC) Films Synthesized from Microalgae (Chlorella vulgaris)

Abstract Bio-based plasticizers for PVC films are being explored to replace conventional phthalate-based plasticizers due to the threats they pose to human health and the environment. In the present study, fatty acids from Chlorella vulgaris were extracted via Microwave-assisted Extraction and were epoxidized using esterification and transesterification reactions in a magnetically stirred reactor to produce EFAME plasticizer. FTIR Analysis determined the presence of an epoxy group as the peak C=O stretch (1739.79 cm−1) was detected. PVC films were synthesized at different concentrations of EFAME (30%, 40%, and 60%). At 40% of EFAME, the PVC exhibited high displacement in the tensile strength and elongation at break test, which was used as a basis to produce PVC-A, PVC-B, and PVC-C, and was compared to phthalate-plasticized PVC film, PVC-D. SEM-EDX Analysis verified the presence of PVC and EFAME in the plasticized PVC films as Carbon, Oxygen, and Chlorine elements were detected. PVC A had the lowest weight loss percentage at 40.96% indicating it has developed high migration resistance among the extraction mediums used. DSC analysis confirmed the plasticizing effect of EFAME as the glass transition temperature of bioplasticized PVC films decreased. Using One-way ANOVA, the physicochemical tests of PVC films plasticized with EFAME showed significantly better results than PVC films plasticized by DOP. Thus, the present study indicates that the bio-based plasticizer derived from C. vulgaris is a better and a potential alternative for phthalates in plasticizing PVC films.

Characterization and tribological performance of new epoxy coatings modified with sustainable ionic liquid-graphene nanolubricants

Graphene-based nanolubricants were prepared using the environmentally friendly 2-hydroxyethylammonium lactate (ML) ionic liquid. The Graphene-ML dispersion (MLG) and neat ML were added to Epoxy Resin (ER) in 5 and 10 wt% proportions to study the effect on the curing conditions by means of Differential Scanning Calorimetry (DSC) and oscillatory rheology. A nucleating effect was found for Graphene, while ML presented a plasticizing effect. These findings were confirmed by DSC and Dynamic-Mechanical Analysis (DMA) with a decrease on the mechanical properties and glass transition temperature. ML and MLG were evaluated as external lubricants of epoxy coatings, finding outstanding friction and wear prevention ability. One and two layer ER coatings were deposited on AISI 1015 steel disks. When used as internal lubricant, MLG is able to prevent surface damage on bi-layer ER coatings. Therefore, we provide a novel approach for the preparation of ER composites with environmentally friendly nanolubricants for applications under demanding conditions.

Determinants of environmental changes in human-modified ecosystems: Effects of plastics on moisture gradients, nutrients, and clay properties

Plastic pollution poses a significant threat to ecosystem health worldwide. This study examines the determinants of environmental changes in human-modified ecosystems through a quantitative-qualitative system dynamics modeling approach: field experiments conducted on a 310 m2 unsaturated clay-rich bed and a 2.5 m2 clay-rich shore of a plastic-impacted pond in Shenzhen, China, and a 1.17 ha plastic-impacted clay pit in Musanze, Rwanda; laboratory experiments involving Modified Proctor (MP) and California Bearing Ratio (CBR) tests on natural clay reinforced with polyethylene terephthalate (PET) microplastics, with diameters ranging from 0.25 to 5 mm and at concentrations of 1.25 %, 2.5 %, 3.75 %, 5 %, and 10 % by weight of clay; and plastic dynamic flows analyzed by modeling the life cycle of PET. Field experiments showed that mulch type and thickness were critical factors influencing crack distribution in a plastic-impacted pond bed. Specifically, cracks were dominant in areas with pronounced desiccation and lacking filamentous green algae and PET-dominated plastic waste. Along the 2.5 m moisture gradient in a plastic-impacted pond bed, temperature and moisture significantly influenced nutrients, particularly in pronounced desiccation zones. Laboratory experiments showed that microplastics altered the structural properties of natural clay, decreasing moisture content while increasing dry density and load-bearing capacity. The plastic life cycle underscored the roles of industrial and consumer practices, environmental conditions, and waste management and recycling inefficiencies in driving environmental changes in human-modified ecosystems. The findings underscore the need for effective plastic waste management and recycling to mitigate the ecological impacts of plastic pollution in ecosystems.

Recycling Technologies for Biopolymers: Current Challenges and Future Directions.

Plastic pollution is a major driver of climate change that is associated with biodiversity loss, greenhouse gas emissions, and negative soil, plant, animal, and human health. One of the solutions that has been proposed and is currently reducing the adverse effects of plastic on the planet is the replacement of synthetic plastics with biopolymers. The biodegradable polymers have been adapted for most of the applications of synthetic plastic. However, their use and disposal present some sustainability challenges. Recycling emerges as an effective way of promoting the sustainability of biopolymer use. In this article, we review recycling as a viable solution to improve the sustainability of biopolymers, emphasizing the current types and technologies employed in biopolymer recycling and the challenges faced in their adoption. Our exploration of the future directions in the conversion of biopolymers into new polymers for reuse establishes a connection between established continuous technological innovation, integration into circular economy models, and the establishment and strengthening of collaborations among key stakeholders in relevant industries as necessary steps for the adoption, full utilization, and improvement of recycling technologies for biopolymers. By connecting these factors, this study lays a foundation for the establishment of a roadmap for improved biopolymer recycling technologies and processes that promote the sustainability of synthetic plastic alternatives.

Evaluation of the Chemical Structure and Thermal Properties of Polyethylene Glycol (PEG)-Doped Polylactic Acid (PLA)/Multiwalled Carbon Nanotube (MWCNT) Composites

This study aimed to investigate the chemical structure, thermal properties, and stability of polylactic acid (PLA) composites blended with multi-walled carbon nanotubes (MWCNTs) and polyethylene glycol (PEG). The composites were fabricated using a masterbatch blending method with two different molecular weights (Mw) of PEG. The masterbatch was initially prepared using solvent casting with chloroform as the solvent, followed by melt blending using an extruder. ATR-FTIR spectroscopy identified strong hydrogen bonds between the C=O groups of PLA and the –OH groups of PEG, as evidenced by the peak at 1748 cm¹. Differential Scanning Calorimetry (DSC) revealed that incorporating 14 wt% of PEG 10,000 into PLA/MWCNT composite significantly enhances the melting enthalpy (∆Hm) from 18.3 J/g to 24.6 J/g and the degree of crystallinity from 2% to 17.3%. The glass transition temperature (Tg) decreased with the addition of PEG, indicating increased chain mobility, while the melting temperature (Tm) remained relatively constant around 158 oC regardless of the PEG Mw. Despite the plasticizing effect of PEG, the thermal stability of the composites was maintained across different PEG Mw. Scanning Electron Microscope (SEM) images showed that MWCNTs were well dispersed within the blend, facilitated by ultrasonic stirring during preparation.

Unveiling the Correlation among Microstructure, Texture, Slip System Activity, and Tensile Property in a Hot Rolled Ni Containing Medium‐Mn Steel

The microstructure–texture–tensile property relationships in a Ni‐containing medium‐Mn steel (Ni‐MMS), subjected to limited thermomechanical processing steps (i.e., hot forging and hot rolling), have been established in this study. The microstructure of the specimens hot rolled (HR) at 1173 (HR‐1173K) and 1373 K (HR‐1373K) exhibits ferrite and austenite phases. The austenite phase fraction in the HR‐1173K specimen is found to be higher than the HR‐1373K condition. The volume fraction of austenite to martensite transformation during tensile testing is also observed to be higher in the HR‐1173K specimen (≈13%) than the HR‐1373K condition (≈2%). This suggests the occurrence of more efficient transformation‐induced plasticity effect in the HR‐1173K specimen in comparison to the HR‐1373K condition, resulting in improved strength–ductility synergy in the former specimen. The smaller grain size of both the phases and higher fraction of twin boundaries as well the evolution of higher intensity γ‐fiber &lt;111&gt;//ND in the HR‐1173K specimen leads to better tensile properties. In addition, the overall activation of the primary slip systems (combination of face‐centered cubic and body‐centered cubic phases slip system), estimated through visco‐plastic self‐consistent simulation, is higher in HR‐1173K specimens, resulting in improved strain hardening response as compared to HR‐1373K one.

Facilitation of Evolution by Plasticity Scales with Phenotypic Complexity

Developmental plasticity enables organisms to cope with new environmental challenges. If deploying such plasticity is costly in terms of time or energy, the same adaptive behaviour could subsequently evolve through piecemeal genomic reorganisation that replaces the requirement to acquire that adaptation by individual plasticity. Here, we report a new dimension to the way in which plasticity can drive evolutionary change, leading to an ever-greater complexity in biological organisation. Plasticity dramatically accelerates the evolutionary accumulation of adaptive systems in model organisms with relatively low rates of mutation. The effect of plasticity on the evolutionary growth of complexity is even greater when the number of elements needed to construct a functional system is increased. These results suggest that, as the difficulty of challenges from the environment becomes greater, plasticity exerts an ever more powerful role in meeting those challenges and in opening up new avenues for the subsequent evolution of complex adaptations.

Gene Expression Divergence in Eugenia uniflora Highlights Adaptation across Contrasting Atlantic Forest Ecosystems

Understanding the evolution and the effect of plasticity in plant responses to environmental changes is crucial to combat global climate change. It is particularly interesting in species that survive in distinct environments, such as Eugenia uniflora, which thrives in contrasting ecosystems within the Atlantic Forest (AF). In this study, we combined transcriptome analyses of plants growing in nature (Restinga and Riparian Forest) with greenhouse experiments to unveil the DEGs within and among adaptively divergent populations of E. uniflora. We compared global gene expression among plants from two distinct ecological niches. We found many differentially expressed genes between the two populations in natural and greenhouse-cultivated environments. The changes in how genes are expressed may be related to the species’ ability to adapt to specific environmental conditions. The main difference in gene expression was observed when plants from Restinga were compared with their offspring cultivated in greenhouses, suggesting that there are distinct selection pressures underlying the local environmental and ecological factors of each Restinga and Riparian Forest ecosystem. Many of these genes engage in the stress response, such as water and nutrient transport, temperature, light intensity, and gene regulation. The stress-responsive genes we found are potential genes for selection in these populations. These findings revealed the adaptive potential of E. uniflora and contributed to our understanding of the role of gene expression reprogramming in plant evolution and niche adaptation.

Comparing Low-Dose Carvedilol Continuous Manufacturing by Solid and Liquid Feeding in Self-Emulsifying Delivery Systems via Hot Melt EXtrusion (SEDEX)

Background/Objectives: This study compared two pilot scale continuous manufacturing methods of solid self-emulsifying drug delivery systems (SEDDSs) via hot melt extrusion (HME). Methods: A model poorly water-soluble drug carvedilol in low dose (0.5–1.0% w/w) was processed in HME either in a conventional powder form or pre-dissolved in the liquid SEDDS. Results: HME yielded a processable final product with up to 20% w/w SEDDS. Addition of carvedilol powder resulted in a non-homogeneous drug distribution in the extrudates, whereas a homogeneous drug distribution was observed in pre-dissolved carvedilol. SEDDSs were shown to have a plasticizing effect, reducing the HME process torque up to 50%. Compatibility between excipients and carvedilol in the studied ratios after HME was confirmed via DSC and WAXS, demonstrating their amorphous form. Solid SEDDSs with Kollidon® VA64 self-emulsified in aqueous medium within 15 min with mean droplet sizes 150–200 nm and were independent of the medium temperature, whereas reconstitution of Soluplus® took over 60 min and mean droplet size increased 2-fold from 70 nm to 150 nm after temperature increased from 25 °C to 37 °C, indicating emulsion phase inversion at cloud point. Conclusions: In conclusion, using Kollidon® VA64 and pre-dissolved carvedilol in SEDDS has shown to yield a stabile HME process with a homogenous carvedilol content in the extrudate.

Effect of path-dependent plasticity on springback in reverse bending and its application to roll forming

This study investigates springback behavior in martensitic advanced high-strength steels (AHSS) undergoing pure bending and reverse bending sequences. The comparison between a conventional isotropic hardening model and the Homogeneous Anisotropic Hardening (HAH20) model had been made, which accounts for non-isotropic hardening effects. Both models were calibrated using uniaxial tensile, cyclic, and loading–unloading tests. The results show that the HAH20 model predicts a higher initial springback compared to the isotropic model. However, reverse bending significantly reduces the overall springback for both models due to a minimized recovery moment. In scenarios with reverse bending, a specific strain exists where both models predict identical springback due to the secondary Bauschinger effect in tensile stress. This phenomenon is also observed in roll forming, a sequential bending process that incorporates reverse bending steps. Experimental findings from roll forming confirm a decrease in springback after the reverse bending stage. Furthermore, the study explores the impact of non-isotropic hardening on the part crashworthiness with the calibration of cross-loading effects. The Bauschinger effect and cross-loading contraction were found to reduce the maximum crash load by 6.2%.

Microstructure evolution in laser powder bed fusion melted 2205 duplex stainless steel using in-situ EBSD during uniaxial tensile testing

Compared to duplex stainless steels (DSSs) prepared by traditional methods, specimens produced through laser powder bed fusion (LPBF) exhibit excellent yield strength but lower elongation. To improve elongation, understanding microstructure evolution during uniaxial tensile testing is crucial. This study investigates the slip behavior, grain boundary evolution, and phase transformation of LPBF 2205 duplex stainless steel during tensile deformation using in-situ electron backscatter diffraction (EBSD). Results show the formation of slip bands, which increase in number as loading stress rises. The primary slip systems activated are {110}<111> in ferrite and {111}<110> in austenite. In the ferrite phase, slip dislocations accumulate and generate low-angle grain boundaries (LAGBs), which evolve into high-angle grain boundaries (HAGBs), refining the grain structure. Numerous Σ3 annealing twins form in the austenite phase, but detwinning and twinning reduce Σ3 content as deformation processes. Ferrite and austenite exhibit good stability during the initial stages of tensile deformation. However, some austenite transforms into martensite through the transformation-induced plasticity (TRIP) effect at the final stages of deformation, which helps relieve stress concentration and delays material fracture. This study provides valuable insights for optimizing microstructure to improve the mechanical properties of LPBF materials.

Influence of environmental humidity during filament storage on the structural and mechanical properties of material extrusion 3D-printed poly(lactic acid) parts

Material extrusion (MEX) is one of the most widely used additive manufacturing techniques these days. This study investigates how the properties of MEX 3D-printed objects depend on the relative humidity (RH) conditions in which filaments are stored before and during the manufacturing process. Poly(lactic acid) (PLA) filament was drawn directly from a humidity-controlled chamber into the MEX 3D printer's nozzle. For each set of samples, the filaments were conditioned under different RH conditions, ranging from 10 % to 90 %. The macrostructure of the fabricated products was characterized using computed tomography, revealing increased porosity at higher RH values (from 0.84 % to 4.42 %). The increased porosity at higher storage RH is attributed to under-extrusion and volatile entrapment due to excess moisture. With growing storage RH, the melt flow rate of PLA also gradually increased, indicating a plasticizing effect of humidity on the biopolymer. Gel permeation chromatography and differential scanning calorimetry analyses were conducted to determine whether hydrolytic chain scission took place when PLA was processed in the presence of excessive moisture. Neither measurement indicated any considerable alteration in molecular integrity and crystalline structure as a function of storage RH. Mechanical tests, however, revealed a reduced load-bearing capacity of the manufactured PLA specimens. Flexural strength decreased from 103.0 to 99.6 MPa, and the impact strength dropped from 18.2 to 16.2 kJ/m2, which is ascribed to the increasing size of pores inside the specimens with increasing storage RH. These findings should be taken into account when designing and processing PLA products by MEX-based additive manufacturing.

A novel high-Mn duplex twinning-induced plasticity lightweight steel with high yield strength and large ductility

In this study, we report a novel high-Mn Fe–21Mn–6Al–4Si–1C (wt.%) duplex lightweight steel with concurrent chemical ordering and twinning-induced plasticity effects. This steel is capable of achieving an exceptional combination of strength and ductility following either cold-rolling and annealing at 1000 °C or subsequent short-term aging at 550 °C. In its as-annealed state, this steel primarily consists of γ-austenite and α-ferrite, with α-ferrite appearing as dispersed particles within fully recrystallized γ grains. Furthermore, L′12- and D03-type ordered nanodomains exist within these two phases, respectively. The aging treatment negligibly affects the size and volume fraction of both the γ-austenite and α-ferrite, yet it enhances the degree of ordering as well as the size and volume fraction of their ordered nanodomains, leading to a rise in yield strength from ∼800 to ∼1062 MPa and a decline in total elongation from ∼60.4% to ∼44.4%. The high yield strength of this steel originates from multiple strengthening mechanisms involving dislocation interactions with solute atoms, ordered nanodomains, γ grain boundaries and γ/α phase boundaries. This steel plastically deforms via planar slip during the initial stages. The rather small γ grain size, coupled with the presence of hard α-ferrite particles, fosters the dynamic slip band refinement (DSBR) effect, thereby enhancing the flow stress sufficiently to trigger deformation twinning in the steel during the later stages. The DSBR effect, combined with the progressive formation of deformation twins, stacking faults and Lomer-Cottrell locks, imparts pronounced strain hardenability to this steel, leading to its outstanding ductility.

Latitudinal trends in an invasive plant: genetic differentiation, phenotypic plasticity, and the effects of heavy metals and herbivores on growth, defence, and reproductive characteristics

Abstract Background and Aims Invasive species usually demonstrate remarkable adaptability across diverse environments, successfully inhabiting a wide variety of regions. This adaptability often links to genetic differentiation and phenotypic plasticity, leading to latitudinal trends in phenotypic traits. In this study, we collected seeds of invasive plant Phytolacca americana from different latitudes and planted them in homogeneous gardens to investigate the latitudinal variation of P. americana phenotypic traits and to evaluate the effects of herbivory and heavy metals on plant growth, defence, and reproductive characteristics. Methods P. americana seeds from different latitudes were planted in a homogeneous garden. For the experimental treatment, the seeds were divided into four groups: a heavy metal treatment group and its corresponding control group, and a cover treatment group with its corresponding control group. After the fruits matured, their growth, reproduction, and defence indicators were measured. Key Results Significant latitudinal trends were observed in P. americana’s growth and defence characteristics, including changes in branch number, underground biomass, total biomass, and leaf tannin content. Compared to previous field surveys on P. americana, our study found that the latitude trends in growth structure and defence traits were consistent. But the latitudinal trend of reproductive structure is different. Moreover, heavy metals and herbivory substantially influenced the plant’s growth, reproduction, and defence mechanisms, further shaping its latitudinal patterns. Conclusions The observed phenotypic variations in P. americana across latitudes can be largely attributed to the synergistic effects of phenotypic plasticity and genetic variation. At a broader geographical scale, adaptations to heavy metal stress and herbivory pressure among different P. americana populations involve distinct trade-offs related to growth, reproduction, and defence strategies.

Thyroid under Attack: The Adverse Impact of Plasticizers, Pesticides, and PFASs on Thyroid Function

Endocrine-disrupting chemicals (EDCs) are synthetic or natural compounds that interfere with the endocrine system, inducing harmful effects on organisms depending on the dose and period of exposure. Numerous studies have identified concerning amounts of EDCs in environmental and human samples. The thyroid gland is essential for thyroid hormone production and controls several body functions. Several EDCs have been classified as thyroid disruptors, impairing thyroid hormone production, synthesis, metabolism, transport, and/or actions. Notably, thyroid disorders are the second most prevalent endocrine disease worldwide, with incidence increasing significantly in recent years. Some studies have correlated this rise in thyroid dysfunctions and cancers with increased exposure to EDCs. Although many EDCs are linked to thyroid dysfunction, this review focuses on the deleterious effects of plasticizers, organochlorine pesticides, and per- and poly-fluoroalkyl substances on thyroid function. These contaminants are commonly found in food, water, and everyday products. Although the impact of human exposure to these EDCs is controversial, numerous epidemiological, in vivo, and in vitro studies have indicated their harmful effects on thyroid function. Given the critical role of thyroid function and hormone production in growth, metabolism, and development, this review summarizes the consequences of exposure to thyroid disruptors for human health.

Consequences of repeated hyperbaric hydrogen exposures on mechanical properties and microstructure of polyamide 11

The objective was to evaluate the impact of repeated exposure to hyperbaric hydrogen (90 MPa; 30 °C) and pressure release on the microstructure and mechanical behavior of PA11. Samples were analyzed after 1, 2, 5 and 10 cycles, by SAXS, WAXS, DMA, DSC, and a series of mechanical tests with variable triaxiality ratio. The most visible change in the residual state after desorption was a stiffening of the amorphous phase. It mainly originated from the first cycle, especially the first pressurization. The crystalline phase was slightly affected and no evidence of nano-voiding was brought in the residual state up to 10 cycles. Similar analyses were conducted during the first cycle's desorption transient. They showed a reversible plasticizing effect and a trend of nano-voiding vanishing after desorption but might promote damage upon further triaxial loading.