Intermolecular interactions in condensed phases often lead to pronounced modulation of the excited-state properties of organic emitters, yet controlled dimerization-either through covalent linkage or supramolecular association-has only recently been recognized as a distinct and powerful molecular-engineering strategy. Despite the rapidly growing interest, comprehensive understanding of how dimer formation governs electronic coupling and excited-state relaxation remains limited, although the phenomenon is of great significance in photophysics, photochemistry, materials science, and optoelectronic device engineering. Dimerization not only produces diverse emissive behaviors, such as excimer-type broad emission, thermally activated delayed fluorescence, and room-temperature phosphorescence, but also holds great potential for the development of multifunctional organic photonic systems with tunable color purity, extended lifetimes, and responsive characteristics. In this concept, we first summarize representative classes of purely organic luminescent dimers that have been reported to date. Second, the underlying mechanisms of dimer-induced excited-state pathways are discussed, with emphasis on the relationship between dimer geometry, electronic coupling, and emission characteristics. Moreover, perspectives on rationally exploiting molecular dimerization for advanced optoelectronic applications are presented, aiming to inspire future design of high-performance organic photofunctional materials.
The Guangdong-Hong Kong-Macao (GHM) region (especially the Greater Bay Area), a low-lying economic hub in southern China, faces complex particulate matter (PM2.5) pollution dynamics under the combined influence of monsoonal systems and global warming. While long-term PM2.5 reductions are documented, phase-specific trends remain obscured. Here, we analyze high-resolution ChinaHighPM2.5 dataset observations (2000-2023) using moving averages and piecewise regression to quantify abrupt shifts in interannual and seasonal PM2.5 trends across the region. We identify 2014 and 2016 as critical breakpoints for annual PM2.5 concentration (Mean(-5y-Year)) and its linear acceleration rate (k(-5y-Year)), respectively. Critical breakpoints delineate phases where declines persisted but decelerated. Prior to 2014, the PM2.5 levels exhibited an upward trend (+0.203 mu g center dot m(-3)center dot a(-1), p > 0.05), which reversed sharply post-2014 (-2.046 mu g center dot m(-3)center dot a(-1), p < 0.01). Spatially, breakpoints clustered post-2014 for concentrations, while acceleration rate shifts reveal a latitudinal divergence near 23 degrees N (23.873 degrees similar to 22.812 degrees N); southern areas transitioned earlier (2010-2011) versus post-2014 in the north. Post-inflection declines are strongest toward the GBA urban core, with winter and autumn driving seasonal improvements (winter: steepest decline -2.646 mu g center dot;m(-3)center dot a(-1); autumn: largest trend reversal Delta-3.961 mu g center dot m(-3)center dot a(-1)), while improvement rates narrowed post-2016 (Delta k = +0.527 mu g center dot m(-3)center dot a(-2)). This study establishes that apparent regional PM2.5 reductions mask significant spatiotemporal heterogeneity, underscoring the necessity of phase-specific analysis for effective pollution control in climatically vulnerable megaregions.
BACKGROUND:Soil cadmium (Cd) contamination poses threats to ecosystems and human health, and the plant arbuscular mycorrhizal fungi (AMF) symbiotic system represents a promising green remediation strategy. However, the underlying mechanisms are complex and context-dependent, and systematic comparative studies remain scarce regarding differential regulation of Cd tolerance enhancement in plants of the same genus but different ecotypes. This study used a native species (Sphagneticola calendulacea), invasive species (Sphagneticola trilobata), and their hybrid as materials. It conducted an integrated analysis of the synergistic effects of inoculating Funneliformis mosseae (FM) on the rhizosphere microenvironment and mineral element uptake of three plants under a Cd stress gradient. The objective was to elucidate the interactive mechanisms by which FM enhances plant Cd tolerance and to evaluate its remediation potential. RESULTS:Results indicate that FM regulation of rhizosphere pH exhibits species specificity but generally alleviates Cd induced acidification. FM significantly enhances acid phosphatase activity in rhizosphere soil and substantially promotes plant phosphorus (P) uptake. FM comprehensively altered plant mineral element uptake, including promoting root accumulation of sodium (Na), magnesium (Mg), and calcium (Ca), shoot potassium (K) allocation, and copper (Cu) and zinc (Zn) absorption. CONCLUSIONS:This study elucidates how FM enhances P uptake and systematically optimizes elemental absorption homeostasis by regulating rhizosphere pH and phosphatase activity. These synergistic effects improve Cd tolerance in Sphagneticola species and highlight the broad potential of AMF-plant symbioses for Cd remediation. It provides crucial theoretical foundations and germplasm selection references for targeted soil restoration using ecologically distinct Sphagneticola ecotypes and their optimal FM partners.
Provided that the initial data (rho 0,v0,eta 0) is of small energy around steady state (rho triangle,0,0), in this work we obtain the global-in-time existence of weak solutions to a fluid particle interaction system. It should be pointed out that vacuum is allowed in this work.
Nanosilver materials are well-known for their broad-spectrum antibacterial properties; nevertheless, they are expensive and may pose health risks at high concentrations. Zinc oxide (ZnO) is regarded as an important photocatalytic antibacterial material, yet its photocatalytic performance remains relatively low. To address this issue, this study employs nanosilver to modify ZnO, resulting in the successful preparation of a ZnO-coated heterostructure material. In this experiment, silver nanowires (AgNWs) are successfully synthesized using the polyol reduction method and subsequently developed ZnO-coated AgNWs heterostructure materials (ZnO/AgNWs) through ultrasonic heating. The results indicate that an optimal quantity of AgNWs can effectively decrease the bandgap of the ZnO-coated materials while enhancing their absorbance in the visible light spectrum, thereby improving the photocatalytic efficiency. This study found that the material exhibits the best photocatalytic performance when an appropriate amount of AgNWs is added. Under this condition, the photocatalytic antibacterial effect can reach 98.4% within 4 h. This modification enhances visible light absorption and enhances the photocatalytic antibacterial effect, thereby improving the material's biocompatibility.
