Microplastics (MPs) or polycyclic aromatic hydrocarbons (PAHs) pollution has received increasing concern due to their ubiquitous distribution and potential risks in soils. However, nothing is known about the influences of PAHs-MPs combined pollution on soil ecosystems. To address the knowledge gap, a 1-year soil microcosm experiment was conducted to systematically investigate the single and combined effect of polyethylene (PE) /phenanthrene (PHE) on soil chemical properties, enzymatic activities and bacterial communities (i.e., diversity, composition and function). Results showed that PE and PHE-PE significantly decreased soil pH. The available phosphorus (AP) and neutral phosphatase activity were not considerably changed by PHE, PE and PHE-PE. Significant enhancement of dehydrogenase activity in a PHE-PE amended system might be due to the degradation of PHE by indigenous bacteria (i.e., Sphingomonas, Sphingobium), and PE could enhance this stimulative effect. PHE and PHE-PE led to a slight increase in soil organic matter (SOM) and fluorescein diacetate hydrolase (FDAse) activity but a decrease in available nitrogen (AN) and urease activity. PE significantly enhanced the functions of nitrogen cycle and metabolism, reducing SOM/AN contents but increasing urease/FDAse activities. There were insignificant impacts on overall community diversity and composition in treated samples, although some bacterial genera were significantly stimulated or attenuated with treatments. In conclusion, the addition of PHE and PE influenced the soil chemical properties, enzymatic activities and bacterial community diversity/composition to some extent. The significantly positive effect of PE on the nitrogen cycle and on metabolic function might lead to the conspicuous alterations in SOM/AN contents and urease/FDAse activities. This study may provide new basic information for understanding the ecological risk of PAHs-MPs combined pollution in soils.

To reveal the similarities and differences in the resistance mechanisms of different ecotypes to Cu stress, a pot experiment was used to systematically compare the physiological responses of non-mining ecotype Miscanthus floridulus (collected from Boluo County, Huizhou City) and mining ecotype Miscanthus floridulus (collected from Dabaoshan mining area) under different Cu concentrations. The results showed that chlorophyll a, chlorophyll b and total chlorophyll in the leaves of the two ecotypes of M. floridulus were negatively correlated with Cu stress concentration (p < 0.01), but the extent of decrease for the ecotypes in the mining area was lower than that for the ecotypes in the non-mining area. The values of chlorophyll a/b for both ecotypes increased with increasing Cu treatment concentration, indicating that Cu is more harmful to chlorophyll b than to chlorophyll a for M. floridulus. Cu stress can lead to the accumulation of malondialdehyde (MDA) in the leaves of M. floridulus with the amount of MDA accumulation observed being greater in the non-mining ecotype than in the mining ecotype (p < 0.05). The content of antioxidant substances (ascorbic acid and reduced glutathione) in the mining ecotype M. floridulus was significantly higher than that in the non-mining ecotype. The activity of SOD in the leaves of non-mining ecotypes was inhibited by Cu stress and the activity of POD was increased by Cu stress. However, the increase in POD in the mining ecotypes was greater than that in the non-mining ecotypes and the activities of the two enzymes in the mining ecotypes were significantly higher than those in the non-mining ecotypes at the highest concentration of Cu. Cu had different effects on PPO activity in the leaves of the two ecotypes of M. floridulus. The plant leaves of the non-mining ecotype at 400 and 800 mg·kg⁻¹ were significantly fewer than those of the control group (p < 0.05), which were 87.1% and 65.2% of the control group, respectively. The PPO activity in the plant leaves of the mining ecotype was higher than that in the leaves of the non-mining ecotype and was significantly higher at 400 and 800 mg·kg⁻¹ than that of the control group (p < 0.05), at 226.5% and 268.1% of the control group, respectively. These results indicate that the mining ecotype M. floridulus is more resistant to copper stress, that resistant ecotypes have been formed, and that small-molecule antioxidant substances play an important role in increasing resistance levels.

Photocatalytic processes have emerged as an efficacious strategy for the removal of organic pollutants from wastewater. In the present investigation, a BiVO₄ nanorod supported on Bi₂O₂S nanosheet catalyst (referred to as BiVO₄/Bi₂O₂S) was meticulously synthesized via a straightforward synthetic approach, aimed explicitly at the photodegradation of tetracycline (TC). The optimized BiVO₄/Bi₂O₂S composite, with a theoretical weight ratio of BiVO₄ to Bi₂O₂S at 2:1 (designated as 2BVO/BOS), demonstrated a significant improvement in tetracycline degradation efficiency, achieving up to 82.9% under visible light irradiation for 90 min. This result stands in stark contrast to the relatively low degradation rates of 42.9% and 50.7% observed for pure BiVO₄ and Bi₂O₂S, respectively. Furthermore, the apparent reaction rate of 2BVO/BOS (approximately 0.01894 min⁻¹) was 3.19-fold and 2.66-fold higher than those of BiVO₄ (0.00594 min⁻¹) and Bi₂O₂S (0.00713 min⁻¹), respectively. This significant improvement in photocatalytic efficacy can be ascribed to the composite’s superior capacity for visible light absorption, as well as its remarkable proficiency in charge carrier separation and transfer. Comprehensive experimental analyses, corroborated by extensive characterization techniques, revealed the formation of a distinctive S-scheme charge transfer mechanism at the interface between BiVO₄ and Bi₂O₂S. This mechanism effectively suppresses charge recombination and optimizes the redox potentials of the photogenerated carriers, thereby enhancing the overall photocatalytic performance. The current study underscores the remarkable potential and promising application of BiVO₄/Bi₂O₂S composite in the realm of wastewater treatment.

Polymeric micelles represent a fundamental self-assembled architecture of gel-based soft materials and have emerged as promising nanocarriers for anticancer drug delivery. Their performance is largely governed by the block composition of constituent copolymers, and understanding their self-assembly behavior provides critical insights into the rational design of gel-related drug delivery systems. In this work, dissipative particle dynamics (DPD) simulations were performed to systematically investigate two types of mixed drug-loaded micellar systems self-assembled from a triblock copolymer mPEG-b-PDEAEMA-b-PMMA (polymer A) with either a diblock copolymer PDEAEMA-b-PMMA (polymer B) or PPEGMA-b-PDEAEMA (polymer C). By tailoring the ratios of hydrophobic (MMA) and pH-sensitive (DMA) blocks, the protonation-responsive behavior, structural stability, drug loading capacity, and release kinetics of the micelles were comprehensively examined. The simulation results demonstrate that: (1) increasing the hydrophobic block ratio accelerates the protonation-triggered micellar swelling and drug release, yet an optimal ratio (+16 MMA) exists beyond which excessive hydrophobic blocks suppress release due to core densification; (2) increasing the pH-sensitive block ratio significantly enhances the maximum drug loading capacity (from 9.83% to 12.22% for the A/C system), but exerts only limited influence on the release rate; (3) the A/C mixed micelles with higher PEG content exhibit superior structural stability and drug loading capacity, while the A/B system with higher MMA content displays more sensitive pH-responsiveness. These findings reveal a competing mechanism between "protonation-driven force" and "structural resistance," providing mesoscopic theoretical guidance for the rational design of pH-responsive gel-related nanocarriers and self-assembled soft materials via block ratio modulation.

Polymeric micelles represent a fundamental self-assembled architecture of gel-based soft materials and have emerged as promising nanocarriers for anticancer drug delivery. Their performance is largely governed by the block composition of constituent copolymers, and understanding their self-assembly behavior provides critical insights into the rational design of gel-related drug delivery systems. In this work, dissipative particle dynamics (DPD) simulations were performed to systematically investigate two types of mixed drug-loaded micellar systems self-assembled from a triblock copolymer mPEG-b-poly(2-(diethylamino)ethyl methacrylate)-b-PMMA (PDEAEMA, hereafter referred to as the DMA block for brevity) with either a diblock copolymer PDEAEMA-b-PMMA (polymer B) or PPEGMA-b-PDEAEMA (polymer C). By tailoring the ratios of hydrophobic (MMA, the constituent block of PMMA) and pH-sensitive (DMA) blocks, the protonation-responsive behavior, structural stability, drug loading capacity, and release kinetics of the micelles were comprehensively examined. The simulation results demonstrate that: (1) increasing the hydrophobic block ratio accelerates the protonation-triggered micellar swelling and drug release because the increased hydrophobic content enhances the core compactness which, upon protonation, generates a stronger driving force for chain extension, yet an optimal ratio (+16 MMA units) exists beyond which excessive hydrophobic blocks suppress release due to core densification; (2) increasing the pH-sensitive block ratio significantly enhances the maximum drug loading capacity (from 9.83% to 12.22% for the A/C system), but exerts only limited influence on the release rate; (3) the A/C mixed micelles with higher PEG content exhibit superior structural stability and drug loading capacity, while the A/B system with higher MMA content displays more sensitive pH-responsiveness. These findings reveal a competing mechanism between “protonation-driven force” and “structural resistance,” providing mesoscopic theoretical guidance for the rational design of pH-responsive polymeric nanocarriers and self-assembled soft materials via block ratio modulation.