Comprehensive investigations of four ratiometric fluorescent chemosensors based on 4-(1H-imidazol-2-yl)benzaldehyde skeleton for malononitrile detection.

Malononitrile is a very important chemical material and has wide application fields in production of medicines, pesticides, and extraction of gold. However, its nonnegligible hypertoxicity inspired researchers to develop more efficient analysis techniques to sensitively and selectively detect malononitrile. Nopinone derivatives initiated by our research group have been developed as a class of organic fluorescent chemosensors for identifying multiple analytes in recent years. Different heterocyclic compounds based on nopinone were designed and synthesized to be applied in the fields of environmental analysis, food detection and bioimaging. Nevertheless, the comparison research on the optical properties of fluorescent compounds containing the nopinyl matrix with other structural analogs including alkyl, cyclohexyl and phenyl groups was deficient. Herein, four 4-(1H-imidazol-2-yl)benzaldehyde-based ratiometric fluorescent chemosensors based on o-dimethyl cyclohexyl, phenyl and nopinyl units for recognizing malononitrile were designed and developed, and their differences in the optical properties and detection performances were investigated by using spectral analysis combined with theoretical calculations. Moreover, the nopinone-based 4-(1H-imidazol-2-yl)benzaldehyde fluorescent chemosensor NMZQ was successfully applied in the dual channel fluorescence bioimaging of malononitrile in living HeLa cells and zebrafish, which attributed to its outstanding spectral property and detection performance.

Platelet membrane-coated oncolytic vaccinia virus with indocyanine green for the second near-infrared imaging guided multi-modal therapy of colorectal cancer.

Colorectal cancer (CRC) is a prevalent malignancy with insidious onset and diagnostic challenges, highlighting the need for therapeutic approaches to enhance theranostic outcomes. In this study, we elucidated the unique temperature-resistant properties of the oncolytic vaccinia virus (OVV), which can synergistically target tumors under photothermal conditions. To capitalize on this characteristic, we harnessed the potential of the OVV by surface-loading it with indocyanine green (ICG) and encapsulating it within a platelet membrane (PLTM), resulting in the creation of PLTM-ICG-OVV (PIOVV). This complex seamlessly integrates virotherapy, photodynamic therapy (PDT), and photothermal therapy (PTT). The morphology, size, dispersion stability, optical properties, and cellular uptake of PIOVV were evaluated using transmission electron microscopy (TEM). In vitro and in vivo experiments revealed specificity of PIOVV for cancer cells; it effectively induced apoptosis and suppressed CT26 cell proliferation. In mouse models, PIOVV exhibits enhanced fluorescence at tumor sites, accompanied by prolonged blood circulation. Under 808 nm laser irradiation, PIOVV significantly inhibited tumor growth. This strategy holds the potential for advancing phototherapy, oncolytic virology, drug delivery, and tumor-specific targeting, particularly in the context of CRC theranostics.

Residue behaviors, degradation, processing factors, and risk assessment of pesticides in citrus from field to product processing.

Pesticide residues in citrus may cause health risks in related juice products, and bring much uncertainty during the processing procedures. In this study, based on the dispersive solid-phase extraction (d-SPE) and UPLC-MS/MS, the residual levels of ten analytes in citrus and its processed products were monitored. The results showed that dissipation of the pesticides followed the first-order kinetics and the half-lives in citrus varied greatly, ranging from 6.36 to 63.0 days. The terminal residues of the five pesticides at harvest time were <0.01-0.302 and <0.01-0.124 mg/kg in raw citrus and citrus flesh, respectively, all of which were lower than the corresponding maximum residue limits (MRLs) of 0.5-1 mg/kg. In the processing experiments, the residues of ten analytes in sterilized juice, concentrated juice, and citrus essential oil were in the range of <0.01 to 0.442 mg/kg, <0.01 to 1.16 mg/kg, and <0.01 to 44.0 mg/kg, respectively, and the corresponding processing factors (PFs) were 0.127-1.00, 0.023-3.06, and 0.006-39.2. Particularly, in citrus essential oil, the PFs of etoxazole, fluazinam, lufenuron and spirotetramat-keto-hydroxy were 1.68-39.2, exhibiting obvious enrichment effects. By integrating the residue data of the field trials and the PFs, the acute and chronic dietary risks of the target pesticides in citrus juice were 0.031-1.83 % and 0.002-2.51 %, respectively, which were far lower than 100 %, demonstrating no unacceptable risk to human health. This work provides basic data for the establishment of the MRLs and dietary exposure risk assessment for processed citrus products.

The Protective Effect of Selenium Nanoparticles in Osteoarthritis: In vitro and in vivo Studies.

Introduction: Osteoarthritis (OA) is a common chronic joint disease characterized by articular cartilage degeneration. OA usually manifests as joint pain, limited mobility, and joint effusion. Currently, the primary OA treatment is non-steroidal anti-inflammatory drugs (NSAIDs). Although they can alleviate the disease's clinical symptoms and signs, the drugs have some side effects. Selenium nanoparticles (SeNPs) may be an alternative to relieve OA symptoms. Materials and Results: We confirmed the anti-inflammatory effect of selenium nanoparticles (SeNPs) in vitro and in vivo experiments for OA disease in this study. In vitro experiments, we found that SeNPs could significantly reduce the expression of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), the major inflammatory factors, and had significant anti-inflammatory and anti-arthritic effects. SeNPs can inhibit reactive oxygen species (ROS) production and increased glutathione peroxidase (GPx) activity in interleukin-1beta (IL-1ß)-stimulated cells. Additionally, SeNPs down-regulated matrix metalloproteinase-13 (MMP-13) and thrombospondin motifs 5 (ADAMTS-5) expressions, while up-regulated type II collagen (COL-2) and aggrecan (ACAN) expressions stimulated by IL-1ß. The findings also indicated that SeNPs may exert their effects through suppressing the NF-κB p65 and p38/MAPK pathways. In vivo experiments, the prevention of OA development brought on by SeNPs was demonstrated using a DMM model. Discussion: Our results suggest that SeNPs may be a potential anti-inflammatory agent for treating OA.

Zinc and cadmium change the metabolic activities and vegetable cellulose degradation of Bacillus cellulasensis in vegetable soils.

Bacillus cellulasensis Zn-B isolated from vegetable soil was highly adaptable to Zinc (Zn) and Cadmium (Cd). Cd, but not Zn, adversely affected the total protein spectrum and functional groups of Bacillus cellulasensis Zn-B. Up to 31 metabolic pathways and 216 metabolites of Bacillus cellulasensis Zn-B were significantly changed by Zn and Cd (Zn&Cd). Some metabolic pathways and metabolites related to functional groups of sulfhydryl (-SH) and amine (-NH-) metabolism were enhanced by Zn&Cd addition. The cellulase activity of Bacillus cellulasensis Zn-B was up to 8.58 U mL-1, increased to 10.77 U mL-1 in Bacillus cellulasensis Zn-B + 300 mg L-1 Zn, and maintained at 6.13 U mL-1 in Bacillus cellulasensis Zn-B + 50 mg L-1 Cd. The vegetables' cellulose content was decreased by 25.05-52.37% and 40.28-70.70% under the action of Bacillus cellulasensis Zn-B and Bacillus cellulasensis Zn-B + 300 mg L-1 Zn. Those results demonstrated that Zn could significantly enhance cellulase activity and biodegradability of Bacillus cellulasensis Zn-B to vegetable cellulose. Bacillus cellulasensis Zn-B can survive in vegetable soil accumulated with Zn&Cd. The tolerance concentration and adsorption capacity of Bacillus cellulasensis Zn-B to Zn were up to 300 mg L-1 and 56.85%, indicating that Bacillus cellulasensis Zn-B acting as a thermostability biological agent had an essential advantage in accelerating the degradation of discarded vegetables by Zn and were beneficial to maintain organic matter content of vegetable soil.

Development of Acid Hydrolysis-Based UPLC-MS/MS Method for Determination of Alternaria Toxins and Its Application in the Occurrence Assessment in Solanaceous Vegetables and Their Products.

In this work, we proposed an acid hydrolysis-based analytical method for the detection of Alternaria toxins (ATs) in solanaceous vegetables and their products with solid-phase extraction (SPE) and ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This study was the first to reveal that some compounds in the eggplant matrix bind to altenusin (ALS). Validation under optimal sample preparation conditions showed that the method met the EU criteria, exhibiting good linearity (R2 > 0.99), matrix effects (-66.6--20.5%), satisfying recovery (72.0-107.4%), acceptable precision (1.5-15.5%), and satisfactory sensitivity (0.05-2 µg/kg for limit of detection, 2-5 µg/kg for limit of quantification). Out of 393 marketed samples, only 47 samples were detected, ranging from 0.54-806 µg/kg. Though the occurrence ratio (2.72%) in solanaceous vegetables could be negligible, the pollution status in solanaceous vegetable products was much more serious, and the incidences were 41.1%. In the 47 contaminated samples, the incidences were 4.26% for alternariol monomethyl ether (AME), 6.38% for alternariol (AOH) and altenuene (ALT), 42.6% for tentoxin (TEN), and 55.3% for tenuazonic acid (TeA).

Tea biochar-immobilized Ralstonia Bcul-1 increases nitrate nitrogen content and reduces the bioavailability of cadmium and chromium in a fertilized vegetable soil.

Pyrolytic biochar (PL-BC, pyrochar) and hydrothermal biochar (HT-BC, hydrochar) derived from branches and leaves of tea plants had different pH, electrical conductivity (EC), total carbon nitrogen content, BET surface area, total pore volume, average pore diameter, and functional groups. HT-BC had a larger specific surface area and more functional groups than PL-BC. Ralstonia Bcul-1 (R-B) was the dominant and functional bacteria in a fertilized vegetable soil supplemented with TBB-immobilized R-B (TBB + R-B). R-B vitality was more closely related to BET surface area, total pore volume, and functional groups of tea-based biochar (TBB: PL-BC and HT-BC). R-B was able to maintain high oxidase activity. R-B and TBB + R-B can increase the activities of urease and peroxidase in vegetable soil playing an essential role in the biotransformation of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N). TBB was able to simultaneously increase the content of NO3--N and NH4+-N, and TBB + R-B also significantly increased NO3--N content but decreased NH4+-N content in a fertilized vegetable soil. These results indicated that R-B promoted nitrification in the soil, i.e. conversion of NH4+-N into NO3--N, by enhancing the activities of urease and peroxidase. R-B had high adsorption capacity for cadmium (Cd) and chromium (Cr) (Cd&Cr: Cd and Cr). Moreover, TBB + R-B was able to convert weak acid extractable and reducible Cd&Cr into a more stable residual fraction and oxidizable Cd&Cr. The overall effect of the treatments was to reduce plant uptake of Cd&Cr by cabbage. TBB + R-B significantly promoted R-B growth, changed inorganic nitrogen speciation, increased NO3--N supply, reduced Cd&Cr bioavailability, and decreased plant tissue Cd&Cr content.

The microsphere of sodium alginate-chitosan-Pichia kudriavzevii enhanced esterase activity to increase the content of esters in Baijiu solid-state fermentation.

Pichia kudriavzevii was one of the important aroma-producing fungi in the solid-state fermentation of Baijiu, and immobilization was an effective strategy for improving microbial performance. Herein, P. kudriavzevii cells were immobilized in a gel network that crosslinked by chitosan and sodium alginate to form sodium alginate/chitosan-P. kudriavzevii microspheres (SA/CS-PMs). Their structural characteristics and formation processes were characterized by SEM and FT-IR. The effect of synthesis conditions on the performance of microspheres were determined by single-factor experiments. Under the optimal conditions, the SA/CS-PMs could increase the amylase activity of the fermentation broth by 57.18%, the esterase activity by 66.13%, the content of ester by 67.04%, and could be reused at least three times. Further research results indicated that the content of ester could be increased significantly in Baijiu solid-state fermentation with the SA/CS-PMs. In conclusion, the SA/CS-PMs could improve the ester production ability of P. kudriavzevii by increasing the esterase activity, which was a valuable exploration of directional biosynthesis and a feasible strategy to improve solid-state fermentation quality.

The RAC/ROP GTPase activator OsRopGEF10 functions in crown root development by regulating cytokinin signaling in rice.

RAC/Rho of plant (ROP) GTPases are major molecular switches that control diverse signaling cascades for plant growth, development, and defense. Here, we discovered a signaling node that connects RAC/ROPs to cytokinins. Rice (Oryza sativa) plants develop a fibrous root system mainly composed of crown roots. Cytokinin signaling via a phosphorelay system is critical for crown root development. We show that OsRopGEF10, which activates RAC/ROPs, acts upstream of the cytoplasmic-nuclear shuttling phosphotransfer proteins AHPs of the cytokinin signaling pathway to promote crown root development. Mutations of OsRopGEF10 induced hypersensitivity to cytokinin, whereas overexpressing this gene reduced the cytokinin response. Loss of OsRopGEF10 function reduced the expression of the response regulator gene OsRR6, a repressor of cytokinin signaling, and impaired crown root development. Mutations in OsAHP1/2 led to increased crown root production and rescued the crown root defect of Osropgef10. Furthermore, auxin activates the ROP GTPase OsRAC3, which attenuates cytokinin signaling for crown root initiation. Molecular interactions between OsRopGEF10, OsRAC3, and OsAHP1/2 implicate a mechanism whereby OsRopGEF10-activated OsRAC3 recruits OsAHP1/2 to the cortical cytoplasm, sequestering them from their phosphorelay function in the nucleus. Together, our findings uncover the OsRopGEF10-OsRAC3-OsAHP1/2 signaling module, establish a link between RAC/ROPs and cytokinin, and reveal molecular crosstalk between auxin and cytokinin during crown root development.

A disposable and sensitive non-enzymatic glucose sensor based on a 3D-Mn-doped NiO nanoflower-modified flexible electrode.

Herein, nanoflower-shaped Mn-doped NiO nano-enzyme composites with high catalytic performance and excellent conductivity were grown on 3D flexible carbon fiber cloth (CFC) via hydrothermal and calcination methods to construct an efficient flexible glucose-sensitive detection electrode. For electrochemical-based sensors, high conductivity is a prerequisite for reliable data acquisition. To avoid the problems associated with using insulating Nafion or paraffin binders, we adopted a strategy of directly growing Mn-doped NiO onto the electrode surface, thereby avoiding interference due to the oxidization of species present in real samples at higher redox potentials, since Ni2+/Ni3+ has low redox potential. Therefore, the electrode has a linear range of 3-5166 µM for glucose detection, with a detection limit as low as 0.28 µM, showing excellent selectivity and reproducibility. The composite-modified electrode provides accurate detection results with real human serum samples, which are in full agreement with those of commercial blood glucose meters. In addition, we tested the glucose content in tea and sorghum fermentation broth at different stages, further expanding the application range of the Mn-NiO sensors. The nano-enzyme sensor fabricated herein offers a new idea for further integration into wearable flexible electronic devices for accurate glucose detection.

Bone metastasis risk and prognosis assessment models for kidney cancer based on machine learning.

Background: Bone metastasis is a common adverse event in kidney cancer, often resulting in poor survival. However, tools for predicting KCBM and assessing survival after KCBM have not performed well. Methods: The study uses machine learning to build models for assessing kidney cancer bone metastasis risk, prognosis, and performance evaluation. We selected 71,414 kidney cancer patients from SEER database between 2010 and 2016. Additionally, 963 patients with kidney cancer from an independent medical center were chosen to validate the performance. In the next step, eight different machine learning methods were applied to develop KCBM diagnosis and prognosis models while the risk factors were identified from univariate and multivariate logistic regression and the prognosis factors were analyzed through Kaplan-Meier survival curve and Cox proportional hazards regression. The performance of the models was compared with current models, including the logistic regression model and the AJCC TNM staging model, applying receiver operating characteristics, decision curve analysis, and the calculation of accuracy and sensitivity in both internal and independent external cohorts. Results: Our prognosis model achieved an AUC of 0.8269 (95%CI: 0.8083-0.8425) in the internal validation cohort and 0.9123 (95%CI: 0.8979-0.9261) in the external validation cohort. In addition, we tested the performance of the extreme gradient boosting model through decision curve analysis curve, Precision-Recall curve, and Brier score and two models exhibited excellent performance. Conclusion: Our developed models can accurately predict the risk and prognosis of KCBM and contribute to helping improve decision-making.

Influence of Active Surveillance on Gleason Score Upgrade and Prognosis in Low- and Favorable Intermediate-Risk Prostate Cancer.

Few studies have focused on the link between active surveillance (AS) and Gleason score upgrade (GSU) and its impact on the prognosis of patients with prostate cancer (PCa). This study aimed to analyze the effect of AS duration on GSU and prognostic value based on risk stratification. All eligible patients were risk-stratified according to AUA guidelines into low-risk (LR), favorable intermediate-risk (FIR), and unfavorable intermediate-risk (UIR) PCa. Within the Surveillance, Epidemiology, and End Results Program (SEER) database, 28,368 LR, 27,243 FIR, and 12,210 UIR PCa patients were included. The relationship between AS duration and GSU was identified with univariate and multivariate logistic regression. Discrimination according to risk stratification of AS duration and GSU was tested by Kaplan-Meier analysis and competing risk regression models. The proportion of patients who chose AS was the highest among LR PCa (3434, 12.1%), while the proportion in UIR PCa was the lowest (887, 7.3%). The AS duration was only associated with GSU in LR PCa, with a high Gleason score (GS) at diagnosis being a strong predictor of GSU for FIR and UIR PCa. Kaplan-Meier analysis indicated that long-term surveillance only made a significant difference in prognosis in UIR PCa. The competing risk analysis indicated that once GS was upgraded to 8 or above, the prognosis in each group was significantly worse. AS is recommended for LR and FIR PCa until GS is upgraded to 8, but AS may not be suitable for some UIR PCa patients.

PHF21A expression as a biomarker of hepatocellular carcinoma progression and prognosis.

Previous studies have shown that PHF21A is associated with the initiation and progression of various tumors. However, its role in hepatocellular carcinoma (HCC) is still unclear. Thus, this study aimed to determine the expression and clinical significance of PHF21A in HCC. PHF21A expression in 201 liver cancer samples and 129 adjacent normal tissues was detected by immunohistochemistry. The correlation between PHF21A expression and the clinicopathological features and prognosis of HCC was verified in 70 other liver tissue microarray samples. The relationship between PHF21A expression and HCC immune cell infiltration was explored via the Tumor Immune Estimation Resource (TIMER). The mechanism underlying the effect of PHF21A on HCC progression was analyzed by gene set enrichment analysis (GSEA) and protein-protein interaction (PPI) network analysis. Immunohistochemical staining showed that PHF21A expression in HCC tissue was significantly lower than that in adjacent nontumor liver tissue and was associated with patient sex, tumor size, metastasis, and Edmondson grade (p<0.05). Kaplan-Meier analysis demonstrated that low PHF21A expression was associated with a poor prognosis, and Cox regression analysis showed that PHF21A was an independent predictor of prognosis. TIMER analysis showed that PHF21A is positively correlated with tumor immune cell infiltration levels. Functional annotation indicated that PHF21A is involved in important pathways, including transcriptional deregulation pathways in cancer. Finally, in vitro experiments confirmed the low expression of PHF21A in HCC cells. PHF21A affects the progression and prognosis of HCC, suggesting that PHF21A may play an important role in monitoring and preventing the development of HCC.

The signal axis GATA2-EDN1-AGT induced hypertension from obstructive sleep apnea-hypopnea syndrome with the clinical and animal study.

Hypertension occurred in 50% obstructive sleep apnea-hypopnea syndrome (OSAHS) patients meanwhile OSAHS occurred in 30% hypertension patients. The present study aimed to explore the molecular mechanism of GATA2-EDN1-AGT induced hypertension in the development of obstructive sleep apnea-hypopnea syndrome. OSAHS patients (56 cases: 36 cases of male, 20 cases of female, 42~60 years old) were divided into two groups (case group: patients with hypertension monitored by 24 h ambulatory blood pressure and polysomnography; control group: patients without hypertension). Wistar rats were used to establish the OSAHS model (narrow pharyngeal cavity). PaO2 and PaCO2 of patients and rats were measured by an automatic blood gas analyzer. The profile of total protein in the OSAHS group and normal group was evaluated. Protein-protein-interaction (PPI) was carried out to show all matter proteins related. The levels of EDN-1, AGTII and atrial natriuretic peptide (ANP) in blood samples of patients and rats were analyzed by enzyme-linked immunosorbent assay (ELISA). The expression of GATA2, EDN1, endothelin-converting enzyme 1 (ECE-1) and AGTⅡ was measured. The results showed that SaO2 and AHI were positively associated with systolic pressure (P<0.05) in OSAHS patients. There was no correlation among other indexes (P>0.05). It was also observed that GATA2 had a strong relationship with AGTⅡ and EDN1. The results of ELISA presented that the levels of EDN1, AGTⅡ and ANP in the OSAHS group of human and animal models were significantly increased (P<0.05). The results of immunochemistry showed that the expression of GATA2 and AGTⅡ in the vascular of OSAHS group was upregulated manifestly (P<0.05). It was concluded that OSAHS can induce AHI, which increases hypertension via the GATA2-EDN1-AGT Ⅱ axis.

Design, synthesis of novel triptolide-glucose conjugates targeting glucose Transporter-1 and their selective antitumor effect.

Six positional isomers of triptolide-glucose conjugates (TG1α, TG1ß, TG2, TG3, TG4 and TG6) were designed and synthesized. These conjugates exhibited better water solubility, and had selective cytotoxicity between tumor cells with high expression of glucose transport-1 (Glut-1) and non-tumor cells with low expression of Glut-1, in which TG2 formed by triptolide (TPL) and d-glucose C2-OH had the strongest cytotoxicity to tumor cells and lowest toxicity in non-tumor cells, therefore the highest relative therapeutic index, which was 5.7 times that of triptolide and consequent the most powerful selective antitumor activity in vitro. The cytotoxicity of TG2 was highly correlated with Glut-1 function. As a prodrug of triptolide, TG2 could promote RNA Pol II degradation and induce apoptosis as TPL does. TG2 had a stronger dose-dependent antitumor effect in vivo than TPL and no adverse reaction occurred when its tumor inhibition was higher than 90%, which was associated with its selective distribution in tumor tissues. TG2 could be used as a promising drug candidate for the treatment of solid tumors with high expression of Glut-1, which is worthy of further study.

Bcl-2 hijacks the arsenic trioxide resistance in SH-SY5Y cells.

Aresenic trioxide (ATO) is proven to be active against leukaemia cells by inducing apoptosis and differentiation. Even though ATO could effectively induce remissions of leukaemia cells, the drug resistance was observed occasionally. To further dissect the mechanism of ATO resistance, we selected the ATO-resistant SH-SY5Y cells and found that Bcl-2 controlled the sensitivity of ATO in SH-SY5Y cells. We report that necroptosis, autophagy, NF-ƘB and MAPK signalling pathway are not involved in ATO-induced apoptosis. Moreover, the ATO-resistant cells showed distinct mitochondrial morphology compared with that of ATO-sensitive cells. Intriguingly, nude mice-bearing ATO-sensitive cells derived xenograft tumours are more sensitive to ATO treatment compared with that of ATO-resistant cells. These data demonstrate that cancer cells can acquire the ATO-resistance ability by increasing the Bcl-2 expression.

Identification of a novel heavy metal resistant Ralstonia strain and its growth response to cadmium exposure.

A novel Ralstonia Bcul-1 strain was isolated from soil samples that was closest to Ralstonia pickettii. Broad-spectrum resistance was identified to a group of heavy metal ions and tolerance to concentrations of Cd2+ up to 400 mg L-1. Low concentrations of heavy metal ions did not have distinctive impact on heavy metal resistance genes and appeared to induce greater expression. Under exposure to Cd2+, cell wall components were significantly enhanced, and some proteins were also simultaneously expressed allowing the bacteria to adapt to the high Cd2+ living environment. The maximum removal rate of Cd2+ by the Ralstonia Bcul-1 strain was 78.97% in the culture medium supplemented with 100 mg L-1 Cd2+. Ralstonia Bcul-1 was able to survive and grow in a low nutrient and cadmium contaminated (0.42 mg kg-1) vegetable soil, and the cadmium removal rate was up to 65.76% in 9th growth. Ralstonia Bcul-1 mixed with biochar could maintain sustainable growth of this strain in the soil up to 75 d and the adsorption efficiency of cadmium increased by 16.23-40.80% as compared to biochar application alone. Results from this work suggests that Ralstonia Bcul-1 is an ideal candidate for bioremediation of nutrient deficient heavy metal contaminated soil.

Determination of 1-methylcyclopropene residues in vegetables and fruits based on iodine derivatives.

An innovative method was established for the determination of 1-methylcyclopropene (1-MCP) in vegetables and fruits. Due to its small molecular weight and low boiling point, it was difficult to obtain quantitative analysis for 1-MCP, especially at the residual level. In this work, based on its iodine derivatives, 1-MCP was derived to 1,2-diiodo-1-methylcyclopropane, which was much easier for trace and accurate chromatographic analysis. During the method validation, the method validation results were satisfactory in terms of linearity (4 ~ 400 µg/L, and R2 ≥ 0.959), matrix effect (-89% ~ -13%), accuracy (80 ~ 100%), sensitivity (limits of quantification, 5 µg/kg) and precision (relative standard deviations ≤ 19%), which was in accordance with the Chinese guidelines for the testing of pesticide residues in crops. Finally, the proposed analytical method was used to monitor the 1-MCP residue levels in commercially available samples, and all the values were below 5 µg/kg, which satisfied the EU or Japan MRLs of 1-MCP.

Residue behavior and dietary risk assessment of six pesticides in pak choi using QuEChERS method coupled with UPLC-MS/MS.

A reliable and simple modified QuEChERS method with UPLC-MS/MS was developed for the simultaneous determination of six pesticides (dimethomorph, imidaclothiz, lufenuron, methoxyfenozide, pyridaben, spinetoram) and their metabolites in pak choi. Method validation indicated good linearity (R2 ≥ 0.99), accuracy (recoveries of 75%-112%), sensitivity (limits of quantification, 0.002-0.01 mg kg-1), and precision (relative standard deviations ≤ 21%), and matrix effects were -36-28%. The half-lives of the six pesticides in pak choi were 2.2-12 d under open field and greenhouse conditions. Considering the short growth cycle of pak choi, the terminal residue levels (0.046-7.8 mg kg-1) and the relevant maximum residue limits (MRLs) of some countries, 5 d was recommended as the pre-harvest interval for the six pesticides on pak choi. Dietary risk assessment revealed that the risk quotients were 3.1%-58% for different gender and age groups in China, indicating none unacceptable public health risk for general population. The results showed that all the six pesticides degraded faster and the terminal residues were much lower under open field conditions than those under greenhouse conditions, which was mainly due to the influence of rainfall, sunlight and other environmental factors. This work was thus significant in assessing the dissipation fate and food safety risks of the six pesticides on pak choi and facilitated the establishment of maximum residue limits.

Disorder-free dynamic localization in non-adiabatic processes: entanglement entropy and OTOC.

We investigate the localization in a one-dimensional modified Peierls model with a non-adiabatic dynamic method. Different from the polaron scenario, here the localization stems from extensive conserved local quantities in the disorder-free lattice. Both the entanglement entropy and out-of-time-ordered correlator (OTOC) show the oscillating feature of dynamically generated localization. Although the strong interaction between electrons may suppress the dynamical features of the localization, but the effect of many-body localization is not observed. The role of disorder presented at finite temperature is discussed as well. The electrons diffuse in a classical manner. Benefitting from the indication of OTOC, it is found that the Anderson localization becomes dominant instead of dynamic localization as observed in disorder-free lattices.