Background: As a systematic fungicide, prochloraz is often used to control banana freckle disease, and it is significant to assess the safety and risk of prochloraz. Methods: The dissipation kinetics ...and distribution of prochloraz in bananas were measured by high-performance liquid chromatography (HPLC). Results: The results showed that the fortified recoveries in bananas were 83.01–99.12%, and the relative standard deviations (RSDs) were 2.45–7.84%. The half-life of prochloraz in banana peel (3.93–5.60 d) was significantly lower than it was in whole banana (8.25–10.80 d) and banana pulp (10.35–12.84 d). The terminal residue of prochloraz in banana fruits was below the maximum residue level (MRL, China) at pre-harvest intervals (PHI) of 21 d. Moreover, the residue of prochloraz in banana peel was always 1.06–7.71 times greater than it was in banana pulp. The dietary risk assessment results indicated that the prochloraz residue in bananas at PHI of 21 d was safe for representative populations. (4) Conclusions: We found that a 26.7% prochloraz emulsion oil in water (EW) diluted 1000-fold and sprayed three times under field conditions was safe and reliable, providing a reference for the safe application of prochloraz in bananas.
In this study, pH-responsive LC@O-CMCS/PU nanoparticles were prepared by encapsulating λ-cyhalothrin (LC) with O-carboxymethyl chitosan (O-CMCS) to form LC/O-CMCS and then covering it with ...polyurethane (PU). Characterization and performance test results demonstrate that LC@O-CMCS/PU had good alkaline release properties and pesticide loading performance. Compared to commercial formulations containing large amounts of emulsifiers (e.g., emulsifiable concentrate, EC), LC@O-CMCS/PU showed better leaf-surface adhesion. On the dried pesticide-applied surfaces, the acute contact toxicity of LC@O-CMCS/PU to Harmonia axyridis (H. axyridis) was nearly 20 times lower than that of LC EC. Due to the slow-releasing property of LC@O-CMCS/PU, only 16.38 % of LC was released at 48 h in dew and effectively reduced the toxicity of dew. On the pesticide-applied leaves with dew, exposure to the LC (EC) caused 86.66 % mortality of H. axyridis larvae significantly higher than the LC@O-CMCS/PU, which was only 16.66 % lethality. Additionally, quantitative analysis demonstrated 11.33 mg/kg of λ-cyhalothrin in the dew on LC@O-CMCS/PU lower than LC (EC) with 4.54 mg/kg. In summary, LC@O-CMCS/PU effectively improves the safety of λ-cyhalothrin to H. axyridis and has great potential to be used in pest control combining natural enemies and chemical pesticides.
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Spodoptera frugiperda (S. frugiperda) is an invasive pest that threatens global crop production and food security and poses a serious threat to maize production worldwide. Metal–organic framework ...(MOF) nanocarriers have great potential for agricultural pest control applications. The present study successfully prepared the chemical cross-linking of iron-based metal–organic framework nanoparticles (MIL-101(Fe)-NH2 NPs) with sodium lignosulfonate (SL) as a pH/laccase double stimuli-responsive pesticide release system. The average particle size of the prepared chlorfenapyr (CF)-loaded nanoparticles (CF@MIL-101-SL NPs) was 161.54 nm, and the loading efficiency was 44.52%. Bioactivity assays showed that CF@MIL-101-SL NPs increased the toxicity of CF to S. frugiperda and caused the rupture of the peritrophic membrane and enlargement of the midgut. Data from 16S rRNA gene sequencing showed that CF@MIL-101-SL treatment reduced the resistance of S. frugiperda to pesticides and pathogens and affected nutrient and energy availability by remodeling the intestinal microbiota of S. frugiperda. The dysregulated microbial community interacted with the broken peritrophic membrane, which exacerbated damage to the host. Nontargeted metabolomic results showed that ABC transporters may be a potential mechanism for the enhanced toxicity of CF@MIL-101-SL to S. frugiperda. In summary, the present study provides effective strategies for toxicological studies of nanopesticides against insects.
In order to evaluate the safety of tebuconazole as a fungicide in bananas, after a simple and rapid pre-treatment, the residues of tebuconazole in different parts of banana were detected by ...high-performance liquid chromatography (HPLC) within 35 days. The mean recoveries and relative standard deviations in banana samples were 87.17 ~ 96.68% and 2.85 ~ 8.49%, respectively. The half-lives of tebuconazole in whole banana, banana pulp, and banana peel were 7.31 ~ 8.68 days, 11.12 ~ 13.39 days, and 4.06 ~ 5.74 days, respectively. It can be seen that tebuconazole dissipated fastest in the peel and slowest in the pulp. And the contents of tebuconazole in banana pulp and banana peel were 3 ~ 35% and 65 ~ 97%, respectively, which can be seen that tebuconazole was mainly distributed in the peel, and only a small part was transmitted to the pulp. Results also showed that the residual amounts of tebuconazole in banana pulp were increased at the first three days and then gradually dissipated, and were below the maximum residue limit (MRL) in China. The results of dietary intake risk assessment showed that the HQ (hazard quotient) were 0.45 ~ 2.69%, which were within the acceptable range. Overall, our research results show that tebuconazole in the field control of banana freckle disease has high security and low risk with the application dose of 133 g/L and diluted 1000 times in water, and can provide an important reference for the rational use of tebuconazole as a systemic fungicide in the field.
Understanding the impact of chitosan-based nanoparticles (NPs) on ecological systems is vital for assessing their environmental behavior and safety. In this study, we investigated the effects of ...pyraclostrobin@chitosan-based nanoparticles (NPs.PYR) on microbial communities in a pond. NPs.PYR significantly impacted the abundance of microbial communities in the pond, compared with the commercial pesticide suspensions. We employed Chlorella sp. as a representative microorganism to explain this phenomenon and found that the NPs and NPs.PYR treatments induced a rapid decrease in the abundance of Chlorella sp. This phenomenon can be attributed to the electrostatic interaction between the NPs and microorganisms, along with the affinity of the microorganisms’ extracellular polymers to the chitosan-based NPs, resulting in the cosettlement of the microorganisms with these NPs. The NPs.PYR migrated from the overlying water to the sediment, decreasing the PYR concentration in the overlying water. The mortality of zebrafish specimens exposed to NPs.PYR was significantly lower than that of the specimens exposed to pyraclostrobin suspension concentrate. These results suggest that the prepared chitosan-based nanopesticide tends to aggregate with microorganisms, leading to cosettlement and reduced pesticide levels in the overlying water, thus enhancing the safety of nontarget animals.
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•Chitosan-based nanopesticide significantly impact the abundance of overlying water microbial communities.•Chitosan-based nanopesticide can aggregate and precipitate alongside microalgae such as Chlorella sp.•Chitosan-based nanopesticide can mitigate eutrophication levels of overlying water.•Compared commercial pesticide suspensions, chitosan-based nanopesticide exhibit higher safety for zebrafish.
Bifenthrin is a pyrethroid pesticide widely used on kumquats, but the residues in the peel and pulp after bifenthrin application at different maturity stages of kumquats have not been evaluated. This ...study developed a simple and rapid high-performance liquid chromatography (HPLC) method for the quantitative analysis of bifenthrin residues in whole fruit, kumquat peel, kumquat pulp, and soil. The results showed that regardless of whether bifenthrin was applied one or three times during the near-mature period, the half-lives of the fruit peel and fruit pulp were longer than those in the immature period. Kumquat fruit residues decreased with time at both maturity levels. The residues of bifenthrin in near-mature fruit exceeded the MRL in Guangxi and Fujian 14 days after the three applications of bifenthrin, suggesting that this issue should be focused on in kumquat production and supervision. However, for bifenthrin application in either the near-mature or the immature fruit period, the calculated risks for chronic dietary intake of kumquat were well below 100%. The data demonstrate that the chronic dietary intake risk of bifenthrin through kumquat consumption is low and within acceptable limits. These results provide a reference and risk assessment data for the safe and rational use of bifenthrin insecticides.
There is increasing evidence that chondrocytes within articular cartilage are affected by endogenous force-related electrical potentials. Furthermore, electrical stimulation (ES) promotes the ...proliferation of chondrocytes and the synthesis of extracellular matrix (ECM) molecules, which accelerate the healing of cartilage defects. These findings suggest the potential application of ES in cartilage repair. In this review, we summarize the pathogenesis of articular cartilage injuries and the current clinical strategies for the treatment of articular cartilage injuries. We then focus on the application of ES in the repair of articular cartilage in vivo. The ES-induced chondrogenic differentiation of mesenchymal stem cells (MSCs) and its potential regulatory mechanism are discussed in detail. In addition, we discuss the potential of applying piezoelectric materials in the process of constructing engineering articular cartilage, highlighting the important advances in the unique field of tissue engineering.
•A semi–analytical force–method solution for a straight–jointed tunnel is proposed.•Nonlinear joint stiffness is considered and expressed as a function of M, N and θ.•An incremental iterative ...algorithm is established for the strong nonlinear system.•The tunnel ultimate bearing capacity under different load distributions is analyzed.
The ultimate bearing capacity of a segmental tunnel lining significantly influences its service performance, particularly when the surrounding soil pressure changes. In this study, a semi–analytical force–method solution for a straight–jointed segmental tunnel lining was derived. The nonlinear joint stiffness was considered and expressed as a function of the bending moment, axial force, and rotational angle of the joint. An incremental iterative algorithm and the corresponding convergence criterion of the proposed model were established for the strong nonlinear system. The proposed model was then verified using the full–scale test results for the loading behavior of the joint and the segmental lining. The structural response of the tunnel under different external load distributions was analyzed using the proposed model, and the main conclusions are as follows. As the lateral pressure coefficient increases, the ultimate bearing capacity of the tunnel lining increases and the length of the first yield platform of the convergence deformation decreases. When P3/P1 increases from 0.71 to 0.83, the ultimate bearing capacity of the tunnel lining increases by 20%, but it has no significant effect on the ultimate convergence deformation. For the lining of the shield tunnel of the Shanghai Metro, the recommended convergent deformation limit is 110 mm.
Osteoarthritis (OA) is a chronic inflammatory disease that is associated with articular cartilage destruction, subchondral bone alterations, synovitis, and even joint deformity and the loss of joint ...function. Although current basic research on the pathogenesis of OA has made remarkable progress, our understanding of this disease still needs to be further improved. Recent studies have shown that the estrogen-related receptor (ERR) family members ERRα and ERRγ may play significant roles in the pathogenesis of OA. In this review, we refer to the latest research on ERRs and the pathogenesis of OA, elucidate the structure and physiopathological functions of the ERR orphan nuclear receptor family, and systematically examine the relationship between ERRs and OA at the molecular level. Moreover, we also discuss and predict the capacity of ERRs as potential targets in the clinical treatment of OA.
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