Browning promotion by the enzymatic oxidation of flavonoids and ʟ-dopa.

This work reports the biological toxicity of nano plastic particles (NPs) to silkworms fed on the bait dopped with polystyrene encapsulated luminescent nanoparticles. The processes of NPs intake and excretion were monitored by means of time-gated optical imaging (TGI) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), which allowed the quantification of the spatiotemporal deposition of NPs in an individual silkworm. The rates of NPs excretion and sequestration were found to be 99.92% and 0.08%, respectively, and the NPs retentate stayed mainly in the fat body (67.7%), digestive tract (18.0%), and head (7.54%). Adverse effects of NPs exposure were accordingly confirmed such as growth retardation and smaller physique. The results of the present work confirmed the possibility of nano-plastics accumulating and transmitting along the food chain in terrestrial ecosystems. The present work demonstrates the potential of employing silkworm as a model of full metamorphosed insects for exploring the biological impact of NPs on congeneric terrestrial animals, as well as the efficacy of the TGI-MS modality for in situ visualizing and quantifying the propagation of NPs via the primary food chain.

In recent years, the adverse effects of nanoplastics (NPs) and pyriproxyfen on aquatic environments have attracted widespread attention. However, research on their combined exposure to aquatic organisms could be more extensive. This work evaluated the acute and chronic toxic effects of polystyrene NPs (PS-NPs) and pyriproxyfen on Daphnia magna (D. magna) under their combined exposure conditions. The addition of PS-NPs within 24 h reduced the acute toxicity of pyriproxyfen to D. magna, resulting in an increase in the 24-h EC₅₀ values of pyriproxyfen on D. magna from 0.24 mg/L to 0.35, 0.51, and 1.26 mg/L, respectively when 1, 5, and 10 mg/L of PS-NPs were added. Compared with PS-NPs, pyriproxyfen significantly disturbed the growth and reproduction of D. magna in the chronic toxicity test at 21 days. The adverse effects caused by pyriproxyfen were alleviated when PS-NPs and pyriproxyfen were co-exposed. In addition, it was observed that the addition of pyriproxyfen resulted in less PS-NPs uptake by D. magna using a time-gated imaging technique. These findings provide new insight into the combined toxic effects of NPs and pyriproxyfen on the reproduction and growth of D. magna, and it is important to understand the effects of complex pollutants on aquatic systems. Moreover, it has provided an important scientific basis for environmental protection and sustainable development.

The performance optimization of photoluminescent (PL) materials is a hot topic in the field of applied materials research. There are many different crystal defects in photoluminescent materials, which can have a significant impact on their optical properties. The luminescent properties and chemical stability of materials can be effectively improved by adjusting lattice defects in crystals. We systematically studied the effect of doping ions on the energy transfer upconversion mechanism in different defect crystals by changing the matrix alkali metal ions. Meanwhile, the influence mechanism of crystal defect distribution on luminescence performance is explored by adjusting the ratio of Na–Li. The PL spectra indicate that changing the alkaline ions significantly affects the luminescence performance and efficiency of UCNPs. The change in ion radius leads to substitution or gap changes in the main lattice, which may alter the symmetry and strength of the crystal field around doped RE ions, thereby altering the UCL performance. Additionally, we demonstrated the imaging capabilities of the synthesized upconversion nanoparticles (UCNPs) in cellular environments using fluorescence microscopy. The results revealed that Na_0.9Li_0.1LuF₄–Yb, Er nanoparticles exhibited significantly enhanced fluorescence intensity in cell imaging compared to other compositions. We further investigated the mechanism by which structural defects formed by doping ions in UCNPs with different alkali metals affect energy transfer upconversion (ETU). This work emphasizes the importance of defect regulation in the ETU mechanism to improve the limitations of crystal structure on the luminescence performance and promote the future application of upconversion nanomaterials, which will provide important theoretical references for the exploration of high-performance luminescent materials in the future.

The effects of nano-plastics (NPs) on aquatic organisms have drawn significant attention. Understanding the uptake and excretion of NPs by aquatic organisms can provide clearer insights into their behavior within organisms. And the effect of different food on the processes is unclear. Daphnia magna (D. magna) is considered as a model organism for assessing the ecological risks of NPs. This work observed the uptake and excretion of NPs by D. magna under different food supply conditions. The effects of three different types of foods (Chlorella sp., Euglena gracilis, and yeast powder) on the uptake and excretion of two concentrations of NPs (1 mg/L and 3 mg/L) by the D. magna were compared. A Time-Gated Imaging technique was used to quantify the NPs uptake mass by D. magna. The study results showed the inhibitory effect presented by food on the uptake of NPs by D. magna. The inhibitory ability of different foods varies, with similar levels observed in Chlorella sp. and E. gracilis, while the inhibitory effect of yeast powder was slightly weaker. The facilitating effect was presented by food on the excretion of NPs. The time constant of excretion of NPs by feeding yeast powder was about 4–5 min longer than that of two types of algae. These effects can be attributed to food occupying the intestine tract of D. magna and supplying energy. This work emphasizes the important role of food in evaluating the ecological effects of NPs and provides support for future research on the long-term risks of pollutants to aquatic organisms and environmental sustainability.