Nano-Micro Core-Shell Fibers for Efficient Pest Trapping.

Insect sex pheromones as an alternative to chemical pesticides hold promising prospects in pest control. However, their burst release and duration need to be optimized. Herein, pheromone-loaded core-shell fibers composed of degradable polycaprolactone and polyhydroxybutyrate were prepared by coaxial electrospinning. The results showed that this core-shell fiber had good hydrophobic performance and thermal stability, and the light transmittance in the ultraviolet band was only below 40%, which provided protection to pheromones. The core-shell structure alleviated the burst release of pheromone in the fiber and extended the release time to about 133 days. In the field, the pheromone-loaded core-shell fibers showed the same continuous and efficient trapping of Spodoptera litura as the commercial carriers. More importantly, the electrospun fibers combined with biomaterials had a degradability unmatched by commercial carriers. The structure design strategy provides ideas for the innovative design of pheromone carriers and is a potential tool for the management of agricultural pests.

Preparation of Thifluzamide Polylactic Acid Glycolic Acid Copolymer Microspheres and Its Effect on the Growth of Cucumber Seedlings.

The polylactic acid-glycolic acid copolymer (PLGA) has been proven to be applicable in medicine, but there is limited research on its application and safety in the agricultural field. In this paper, thifluzamide PLGA microspheres were prepared via phacoemulsification and solvent volatilization, using the PLGA copolymer as the carrier and thifluzamide as the active component. It was found that the microspheres had good slow-release performance and fungicidal activity against Rhizoctonia solani. A comparative study was conducted to show the effect of thifluzamide PLGA microspheres on cucumber seedlings. Physiological and biochemical indexes of cucumber seedlings, including dry weight, root length, chlorophyll, protein, flavonoids, and total phenol content, indicated that the negative effect of thifluzamide on plant growth could be mitigated when it was wrapped in PLGA microspheres. This work explores the feasibility of PLGA as carriers in fungicide applications.

Effect of radical lymphadenectomy in colorectal cancer with para-aortic lymph node metastasis: a systematic review and meta-analysis.

BACKGROUND: Colorectal cancer (CRC) with para-aortic lymph node metastasis (PALNM) is an intractable clinical situation, and the role of radical lymphadenectomy in the treatment of CRC with PALNM is still controversial. The aim of the current system review and meta-analysis is to evaluate the clinical efficacy and safety of radical lymphadenectomy in CRC patients with PALAN. METHODS: We performed a systematic search of PubMed, Embase, Cochrane Library and other online databases up to 31 October 2021. The clinical data including overall survival and postoperative complications were screened and analyzed after data extraction. Odds ratios (ORs) were applied to analyze these dichotomous outcomes with a fixed effects model. RESULTS: A total of 7 available retrospective clinical studies involving 327 patients were finally included. CRC patients with PALNM who underwent radical lymphadenectomy showed significantly overall survival (OR: 6.80, 95% CI: 3.46-13.38, P < 0.01; I2 = 0%) when compared to those who did not receive radical lymphadenectomy. Moreover, in terms of postoperative complications (OR: 0.71, 95% CI: 0.35-1.44, P = 0.48; I2 = 0%), there was no statistical difference between radical lymphadenectomy treatment and control groups. CONCLUSIONS: The radical lymphadenectomy treatment has showed the expected clinical efficacy in prolonging overall survival time of CRC patients with PALAN. Moreover, the preemptive radical lymphadenectomy could not cause additional postoperative complications.

De Ritis Ratio as a Significant Prognostic Factor in Patients with Sepsis: A Retrospective Analysis.

PURPOSE: This study was performed to investigate the relationship between the aspartate transaminase and/or alanine transaminase ratio (DRR) and long-term mortality of patients diagnosed with sepsis or septic shock. MATERIALS AND METHODS: We conducted a retrospective study among adult septic patients who were admitted to the surgical intensive care unit (ICU) of the Chinese People's Liberation Army (PLA) General Hospital from January 2014 to December 2018. Baseline characteristics were compared between survivors and non survivors. We performed univariate and multivariate Cox regression analyses to evaluate the relation of DRR with 180-day mortality. The potential prognostic value of DRR in predicting mortality rate was assessed by receiver operating characteristic (ROC) curve analysis. In addition, we conducted subgroup analysis by the optimal DRR cutoff value. RESULTS: We included a total of 183 patients in the current study, and 44 (24%) patients died within 180 days of hospitalization. Univariate and multivariate Cox analyses revealed that DRR was an independent predictor of 180-day mortality (hazard ratio [HR] 1.421, 95% confidence interval [CI] 1.073-1.883, P = 0.014). The predictive accuracy of DRR for 180-day mortality was presented as an ROC curve, which had an area under the curve (AUC) of 0.708 (95% CI 0.629-0.786, P < 0.001). After we stratified all enrolled patients into two groups by using the optimal cutoff value of 1.29, we observed a significantly higher mortality in patients with a relatively high DRR. CONCLUSIONS: An elevated DRR was associated with higher 180-day mortality among septic patients, and DRR might be an optimal marker for predicting the long-term mortality of sepsis. More prospective and randomized trials are needed to confirm the prognostic value of DRR.

Enhanced Fungicidal Efficacy by Co-Delivery of Azoxystrobin and Diniconazole with Cauliflower-Like Metal-Organic Frameworks NH2-Al-MIL-101.

Long-term use of a single fungicide increases the resistance risk and causes adverse effects on natural ecosystems. Controlled release formulations of dual fungicides with different modes of action can afford a new dimension for addressing the current issues. Based on adjustable aperture and superhigh surface area, metal-organic frameworks (MOFs) are ideal candidates as pesticide release carriers. This study used Al3+ as the metal node and 2-aminoterephthalic acid as the organic chain to prepare aluminum-based metal-organic framework material (NH2-Al-MIL-101) with "cauliflower-like" structure and high surface area of 2359.0 m2/g. Fungicides of azoxystrobin (AZOX) and diniconazole (Dini) were simultaneously encapsulated into NH2-Al-MIL-101 with the loading content of 6.71% and 29.72%, respectively. Dual fungicide delivery system of AZOX@Dini@NH2-Al-MIL-101 demonstrated sustained and pH responsive release profiles. When the maximum cumulative release rate of AZOX and Dini both reached about 90%, the release time was 46 and 136 h, respectively. Furthermore, EC50 values as well as the percentage of inhibition revealed that AZOX@Dini@NH2-Al-MIL-101 had enhanced germicidal efficacy against rice sheath blight (Rhizoctonia solani), evidenced by the synergistic ratio of 1.83. The present study demonstrates a potential application prospect in sustainable plant protection through co-delivery fungicides with MOFs as a platform.

Effective and Sustained Control of Soil-Borne Plant Diseases by Biodegradable Polyhydroxybutyrate Mulch Films Embedded with Fungicide of Prothioconazole.

Soil-borne diseases and plant rhizosphere nematode have caused many crop yield losses. Increased environmental awareness is leading to more restrictions on the use of certain fumigants and root irrigation methods due to their impact on human health and soil system. Therefore, it is necessary to find alternative treatments to maintain crop economic yields and environmental sustainability. In the present work, biodegradable antifungal mulches were prepared by blending poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PHB) with fungicide of prothioconazole (PRO), which were used for effective and sustained control of soil-borne plant diseases. To reveal the application prospect of the PHB/PRO composite films in the management of soilborne plant diseases, some physical and biological properties were evaluated. The proper mulch film of PHB/PRO was assessed based on its mechanical and optical properties, while water solubility and the film micromorphology was further characterized. The release patterns of composite films under different pH levels were investigated. Moreover, the in vitro antifungal bioassay and pot experiment showed satisfactory bioactivity of the PHB/PRO films against Sclerotium rolfsii Sacc., a soil-borne disease in peanut fields. This study demonstrated that the biodegradable mulch films containing PRO fungicide are capable of inhibiting soil-borne plant pathogenic fungi effectively, and this facile but powerful strategy may find wide applicability in sustainable plant and horticulture protection.

The impact of COVID-19 on gastric cancer surgery: a single-center retrospective study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) has been declared a global pandemic by the World Health Organization. Patients with cancer are more likely to incur poor clinical outcomes. Due to the prevailing pandemic, we propose some surgical strategies for gastric cancer patients. METHODS: The 'COVID-19' period was defined as occurring between 2020 and 01-20 and 2020-03-20. The enrolled patients were divided into two groups, pre-COVID-19 group (PCG) and COVID-19 group (CG). A total of 109 patients with gastric cancer were enrolled in this study. RESULTS: The waiting time before admission increased by 4 days in the CG (PCG: 4.5 [IQR: 2, 7.8] vs. CG: 8.0 [IQR: 2,20]; p = 0.006). More patients had performed chest CT scans besides abdominal CT before admission during the COVID-19 period (PCG: 22 [32%] vs. CG: 30 [73%], p = 0.001). After admission during the COVID period, the waiting time before surgery was longer (PCG: 3[IQR: 2,5] vs. CG: 7[IQR: 5,9]; p < 0.001), more laparoscopic surgeries were performed (PCG: 51[75%] vs. CG: 38[92%], p = 0.021), and hospital stay period after surgery was longer (7[IQR: 6,8] vs.9[IQR:7,11]; p < 0.001). In addition, the total cost of hospitalization increased during this period, (PCG: 9.22[IQR:7.82,10.97] vs. CG: 10.42[IQR:8.99,12.57]; p = 0.006). CONCLUSION: This study provides an opportunity for our surgical colleagues to reflect on their own services and any contingency plans they may have to tackle the COVID-19 crisis.

Sulfonate-Functionalized Mesoporous Silica Nanoparticles as Carriers for Controlled Herbicide Diquat Dibromide Release through Electrostatic Interaction.

Environmental stimuli-responsive pesticide release is desirable for enhanced efficiency and reduced side effects. In most cases, the loading and release of pesticides mainly depends on hydrophobic interactions and hydrogen bonding. Electrostatic interaction is less investigated as a weapon for achieving high loading content and controlled pesticide release. In this work, negative-charge decorated mesoporous silica nanoparticles (MSNs) were facilely fabricated by introducing sulfonate groups onto MSNs through a post-grafting method. Sulfonate-functionalized MSNs (MSN-SO3) were synthesized by conversion of epoxy group into sulfonate group using a bisulfite ion as a ring opening reagent. Diquat dibromide (DQ), one of the globally used quaternary ammonium herbicides, was efficiently loaded into these negatively charged MSN-SO3 nanoparticles. The loading content was increased to 12.73% compared to those using bare MSNs as carriers (5.31%). The release of DQ from DQ@MSN-SO3 nanoparticles was pH and ionic strength responsive, which was chiefly governed by the electrostatic interactions. Moreover, DQ@MSN-SO3 nanoparticles exhibited good herbicidal activity for the control of Datura stramonium L., and the bioactivity was affected by the ionic strength of the release medium. The strategy of cargo loading and release dependent on the electrostatic interactions could be generally used for charge-carrying pesticides using carriers possessing opposite charges to mitigate the potential negative impacts on the environment.

Synthesis and Characterization of Stimuli-Responsive Poly(2-dimethylamino-ethylmethacrylate)-Grafted Chitosan Microcapsule for Controlled Pyraclostrobin Release.

Controllable pesticide release in response to environmental stimuli is highly desirable for better efficacy and fewer adverse effects. Combining the merits of natural and synthetic polymers, pH and temperature dual-responsive chitosan copolymer (CS-g-PDMAEMA) was facilely prepared through free radical graft copolymerization with 2-(dimethylamino) ethyl 2-methacrylate (DMAEMA) as the vinyl monomer. An emulsion chemical cross-linking method was used to expediently fabricate pyraclostrobin microcapsules in situ entrapping the pesticide. The loading content and encapsulation efficiency were 18.79% and 64.51%, respectively. The pyraclostrobin-loaded microcapsules showed pH-and thermo responsive release. Microcapsulation can address the inherent limitation of pyraclostrobin that is photo unstable and highly toxic on aquatic organisms. Compared to free pyraclostrobin, microcapsulation could dramatically improve its photostability under ultraviolet light irradiation. Lower acute toxicity against zebra fish on the first day and gradually similar toxicity over time with that of pyraclostrobin technical concentrate were in accordance with the release profiles of pyraclostrobin microcapsules. This stimuli-responsive pesticide delivery system may find promising application potential in sustainable plant protection.

Synthesis of Pyrimethanil-Loaded Mesoporous Silica Nanoparticles and Its Distribution and Dissipation in Cucumber Plants.

Mesoporous silica nanoparticles are used as pesticide carries in plants, which has been considered as a novel method to reduce the indiscriminate use of conventional pesticides. In the present work, mesoporous silica nanoparticles with particle diameters of 200-300 nm were synthesized in order to obtain pyrimethanil-loaded nanoparticles. The microstructure of the nanoparticles was observed by scanning electron microscopy. The loading content of pyrimethanil-loaded nanoparticles was investigated. After treatment on cucumber leaves, the concentrations of pyrimethanil were determined in different parts of cucumber over a period of 48 days using high performance liquid chromatography tandem mass spectrometry. It was shown that the pyrimethanil-loaded mesoporous silica nanoparticles might be more conducive to acropetal, rather than basipetal, uptake, and the dosage had almost no effect on the distribution and dissipation rate in cucumber plants. The application of the pesticide-loaded nanoparticles in leaves had a low risk of pyrimethanil accumulating in the edible part of the plant.

Investigation of Gallium Arsenide Deformation Anisotropy during Nanopolishing via Molecular Dynamics Simulation.

Crystal orientation significantly influences deformation during nanopolishing due to crystal anisotropy. In this work, molecular dynamics (MD) simulations were employed to examine the process of surface generation and subsurface damage. We conducted analyses of surface morphology, mechanical response, and amorphization in various crystal orientations to elucidate the impact of crystal orientation on deformation and amorphization severity. Additionally, we investigated the concentration of residual stress and temperature. This work unveils the underlying deformation mechanism and enhances our comprehension of the anisotropic deformation in gallium arsenide during the nanogrinding process.

Efficient delivery of the herbicide quinclorac by nanosuspension for enhancing deposition, uptake and herbicidal activity.

BACKGROUND: The presence of barnyardgrass poses a threat to global food security by reducing rice yields. Currently, herbicides are primarily applied for weed management. However, the effectiveness of herbicide deposition and uptake on barnyardgrass is limited as a consequence of the high wax content on leaves, low water solubility and extreme lipophilicity of herbicides. Therefore, it is imperative to develop novel formulations for efficient delivery of herbicides to improve herbicidal activity and reduce dosage. RESULTS: We successfully prepared nanosuspension(s) (NS) of quinclorac through the wet media milling technique. This NS demonstrates excellent physical stability and maintains nanoscale during dose transfer. The deposition concentration and uptake concentration of NS on barnyardgrass were 3.84-4.47- and 2.11-2.58-fold greater than those traditional formulations, respectively. Moreover, the NS exhibited enhanced herbicidal activity against barnyardgrass at half the dosage required by conventional formulations without compromising rice safety. CONCLUSIONS: These findings suggest that NS can effectively facilitate the delivery of hydrophobic and poorly water-soluble herbicide active ingredients, thereby enhancing their deposition, uptake and bioactivity. This study expands the potential application of NS in pesticide delivery, which can provide valuable support for optimizing pesticide utilization, improving economic efficiency and mitigating environmental risks. © 2024 Society of Chemical Industry.

Making the Complicated Simple: A Minimizing Carrier Strategy on Innovative Nanopesticides.

The flourishing progress in nanotechnology offers boundless opportunities for agriculture, particularly in the realm of nanopesticides research and development. However, concerns have been raised regarding the human and environmental safety issues stemming from the unrestrained use of non-therapeutic nanomaterials in nanopesticides. It is also important to consider whether the current development strategy of nanopesticides based on nanocarriers can strike a balance between investment and return, and if the complex material composition genuinely improves the efficiency, safety, and circularity of nanopesticides. Herein, we introduced the concept of nanopesticides with minimizing carriers (NMC) prepared through prodrug design and molecular self-assembly emerging as practical tools to address the current limitations, and compared it with nanopesticides employing non-therapeutic nanomaterials as carriers (NNC). We further summarized the current development strategy of NMC and examined potential challenges in its preparation, performance, and production. Overall, we asserted that the development of NMC systems can serve as the innovative driving force catalyzing a green and efficient revolution in nanopesticides, offering a way out of the current predicament.

NUFIP1-engineered exosomes derived from hUMSCs regulate apoptosis and neurological injury induced by propofol in newborn rats.

BACKGROUND: Propofol can increase neurotoxicity in infants but the precise mechanism is still unknown. Our previous study revealed that nuclear FMR1 interacting protein 1 (NUFIP1), a specific ribophagy receptor, can alleviate T cell apoptosis in sepsis. Yet, the effect of NUFIP1-engineered exosomes elicited from human umbilical cord blood mesenchymal stem cells (hUMSCs) on nerve injury induced by propofol remains unclear. This study intended to investigate the effect of NUFIP1-engineered exosomes on propofol-induced nerve damage in neonatal rats. METHODS: Firstly, NUFIP1-engineered exosomes were extracted from hUMSCs serum and their identification was conducted using transmission electron microscopy (TEM), Flow NanoAnalyzer, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot (WB). Subsequently, the optimal exposure duration and concentration of propofol induced apoptosis were determined in SH-SY5Y cell line using WB. Following this, we co-cultured the NUFIP1-engineered exosomes in the knockdown group (NUFIP1-KD) and overexpression group (NUFIP1-OE) with SH-SY5Y cells and assessed their effects on the apoptosis of SH-SY5Y cells using terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) assay, Hoechst 33258 staining, WB, and flow cytometry, respectively. Finally, NUFIP1-engineered exosomes were intraperitoneally injected into neonatal rats, and their effects on the learning and memory ability of neonatal rats were observed through the righting reflex and Morris water maze (MWM) test. Hippocampi were extracted from different groups for hematoxylin-eosin (HE) staining, immunohistochemistry, immunofluorescence, and WB to observe their effects on apoptosis in neonatal rats. RESULTS: TEM, Flow NanoAnalyzer, qRT-PCR, and WB analyses confirmed that the exosomes extracted from hUMSCs serum exhibited the expected morphology, diameter, surface markers, and expression of target genes. This confirmed the successful construction of NUFIP1-KD and NUFIP1-OE-engineered exosomes. Optimal exposure duration and concentration of propofol were determined to be 24 hours and 100 µg/ml, respectively. Co-culture of NUFIP1 engineered exosomes and SH-SY5Y cells resulted in significant up-regulation of pro-apoptotic proteins Bax and c-Caspase-3 in the KD group, while anti-apoptotic protein Bcl-2 was significantly decreased. The OE group showed the opposite trend. TUNEL apoptosis assay, Hoechst 33258 staining, and flow cytometry yielded consistent results. Animal experiments demonstrated that intraperitoneal injection of NUFIP1-KD engineered exosomes prolonged the righting reflex recovery time of newborn rats, and MWM tests revealed a significant diminution in the time and number of newborn rats entering the platform. HE staining, immunohistochemistry, immunofluorescence, and WB results also indicated a significant enhancement in apoptosis in this group. Conversely, the experimental results of neonatal rats in the OE group revealed a certain degree of anti-apoptotic effect. CONCLUSIONS: NUFIP1-engineered exosomes from hUMSCs have the potential to regulate nerve cell apoptosis and mitigate neurological injury induced by propofol in neonatal rats. Targeting NUFIP1 may hold great significance in ameliorating propofol-induced nerve injury.

DIMINISHED EXPRESSION OF GLS IN CD4 + T CELLS SERVES AS A PROGNOSTIC INDICATOR ASSOCIATED WITH CUPROPTOSIS IN SEPTIC PATIENTS.

ABSTRACT: Objectives: Sepsis is defined as a life-threatening disease associated with a dysfunctional host immune response. Stratified identification of critically ill patients might significantly improve the survival rate. The present study sought to probe molecular markers associated with cuproptosis in septic patients to aid in stratification and improve prognosis. Methods: We studied expression of cuproptosis-related genes (CRGs) using peripheral blood samples from septic patients. Further classification was made by examining levels of expression of these potential CRGs in patients. Coexpression networks were constructed using the Weighted Gene Coexpression Network Analysis (WGCNA) method to identify crucial prognostic CRGs. Additionally, we utilized immune cell infiltration analysis to further examine the immune status of septic patients with different subtypes and its association with the CRGs. scRNA-seq data were also analyzed to verify expression of key CRGs among specific immune cells. Finally, immunoblotting, flow cytometry, immunofluorescence, and CFSE analysis were used to investigate possible regulatory mechanisms. Results: We classified septic patients based on CRG expression levels and found significant differences in prognosis and gene expression patterns. Three key CRGs that may influence the prognosis of septic patients were identified. A decrease in GLS expression was subsequently verified in Jurkat cells, accompanied by a reduction in O-GlcNAc levels, and chelation of copper by tetrathiomolybdate could not rescue the reduction in GLS and O-GLcNAc levels. Moreover, immoderate chelation of copper was detrimental to mitochondrial function, cell viability, and cell proliferation, as well as the immune status of the host. Conclusion: We have identified novel molecular markers associated with cuproptosis, which could potentially function as diagnostic indicators for septic patients. The reversible nature of the observed alterations in FDX1 and LIAS was demonstrated through copper chelation, whereas the correlation between copper and the observed changes in GLS requires further investigation.

Systematic analysis of levels of evidence supporting Chinese clinical practice guidelines for gastrointestinal disease.

BACKGROUND: Clinical practice guidelines (CPGs) inform healthcare decisions and improve patient care. However, an evaluation of guidelines on gastrointestinal diseases (GIDs) is lacking. This study aimed to systematically analyze the level of evidence (LOE) supporting Chinese CPGs for GIDs. METHODS: CPGs for GIDs were identified by systematically searching major databases. Data on LOEs and classes of recommendations (CORs) were extracted. According to the Grades of Recommendation, Assessment, Development, and Evaluation system, LOEs were categorized as high, moderate, low, or very low, whereas CORs were classified as strong or weak. Statistical analyses were conducted to determine the distribution of LOEs and CORs across different subtopics and assess changes in evidence quality over time. FINDINGS: Only 27.9% of these recommendations were supported by a high LOE, whereas approximately 70% were strong recommendations. There was a significant disparity among different subtopics in the proportion of strong recommendations supported by a high LOE. The number of guidelines has increased in the past 5 years, but there has been a concomitant decline in the proportion of recommendations supported by a high LOE. CONCLUSIONS: There is a general lack of high-quality evidence supporting Chinese CPGs for GIDs, and there are inconsistencies in strong recommendations that have not improved. This study identified areas requiring further research, emphasizing the need to bridge these gaps and promote the conduct of high-quality clinical trials. FUNDING: This study was supported by the National Key R&D Program of China (2022YFC2503604 and 2022YFC2503605) and Special Topics in Military Health Care (22BJZ25).

Multiplug filtration clean-up with multiwalled carbon nanotubes in the analysis of pesticide residues using LC-ESI-MS/MS.

A novel design for a rapid clean-up method was developed for the analysis of pesticide residues in fruit and vegetables followed by LC-ESI-MS/MS. The acetonitrile-based sample extraction technique was used to obtain the extracts, and further clean-up was carried out by applying the streamlined procedure on a multiplug filtration clean-up column coupled with a syringe. The sorbent used for clean-up in this research is multiwalled carbon nanotubes, which was mixed with anhydrous magnesium sulfate to remove water from the extracts. This method was validated on 40 representative pesticides and apple, cabbage, and potato sample matrices spiked at two concentration levels of 10 and 100 µg/kg. It exhibited recoveries between 71 and 117% for most pesticides with RSDs < 15%. Matrix-matched calibrations were performed with the coefficients of determination >0.995 for most studied pesticides between concentration levels of 10-500 µg/L. The LOQs for 40 pesticides ranged from 2 to 50 µg/kg. The developed method was successfully applied to the determination of pesticide residues in market fruit and vegetable samples.

Detection of caffeine in tea, instant coffee, green tea beverage, and soft drink by direct analysis in real time (DART) source coupled to single-quadrupole mass spectrometry.

Ambient ionization direct analysis in real time (DART) coupled to single-quadrupole MS (DART-MS) was evaluated for rapid detection of caffeine in commercial samples without chromatographic separation or sample preparation. Four commercial samples were examined: tea, instant coffee, green tea beverage, and soft drink. The response-related parameters were optimized for the DART temperature and MS fragmentor. Under optimal conditions, the molecular ion (M+H)+ was the major ion for identification of caffeine. The results showed that DART-MS is a promising tool for the quick analysis of important marker molecules in commercial samples. Furthermore, this system has demonstrated significant potential for high sample throughput and real-time analysis.

Spinach or amaranth may represent highest residue of thiophanate-methyl with open field application on six leaf vegetables.

To select representative crop among leaf vegetables which may contain the highest residue after fungicide uses, open field applications with thiophanate-methyl on six crops including pakchoi, rape, crown daisy, amaranth, spinach and lettuce were designed and conducted. In this study, a high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry with selected reaction monitoring was used to simultaneously determine thiophanate methyl and its metabolite carbendazim residue in various samples. The limit of quantification for thiophanate methyl and carbendazim were established in the range of 0.005-0.01 mg kg(-1) for all samples. It was shown that recoveries ranged from 67.8 % to 102.3 % for thiophanate methyl, and 72.0 %-112.6 % for carbendazim at spiked levels of 0.01-0.1 mg kg(-1). It's found that thiophanate methyl converts to carbendazim very quickly. In supervised field trials, the half-lives of thiophanate methyl in six leaf vegetables were in the range of 1.26-2.65 days, and the half-lives of carbendazim were in the range of 2.53-4.28 days. It was also found that thiophanate methyl residue in spinach and amaranth was higher than others after application. It's recommended that spinach or amaranth can be selected as representative crop in leaf vegetables in study of systemic fungicides with similarity as thiophanate methyl.

Self-Assembled Sphere Covalent Organic Framework with Enhanced Herbicidal Activity by Loading Cyhalofop-butyl.

Nanopesticides are considered to be a novel and efficient kind of tool for controlling pests in modern agriculture. Covalent organic frameworks (COFs), with high surface areas, ordered structures, and rich functional groups for loading pesticides, are a class of promising carrier materials that can be used to develop efficient nanopesticide delivery systems. However, until now, only a strong ionic interaction between the pesticide and COF can be utilized to achieve the combination between the pesticide and COF. On the basis of this method, charged pesticide molecules are the only choice for COF-based nanopesticides, which limits the exploitation. The way to load the uncharged pesticide molecules into COF still needs to be explored. Herein, in this research, we provided a commonly mild and high-efficacy strategy for loading an uncharged pesticide molecule into COF. The herbicide cyhalofop-butyl (CB), as a neutral model pesticide molecule, was loaded into the sphere COF (SCOF, a model COF synthesized at room temperature) without any ionic interaction via the host-guest strategy. The loading capacity of CB into SCOF (CB@SCOF) was determined at 57% (w/w). Smaller CB@SCOF particles (150-200 nm) can efficiently enter the weed leaves and stems, enhancing the accumulation of the effective concentration in weeds, thus increasing herbicidal activity, in comparison to CB emulsifiable (EC, micrometer scale). Furthermore, CB@SCOF had a solubilization effect for CB in water and can improve the photostability of CB. Thus, the CB-loaded COF nanosphere showed excellent herbicidal activities against the target weeds Echinochloa crus-galli and Leptochloa chinensis compared to commercial CB EC. In conclusion, this study also provides a mild and high-efficacy pesticide loading strategy for COFs. The constructed efficient delivery system and pesticide formulation containing herbicidal COF nanospheres exhibit great potential applications for controlling weeds in sustainable agriculture.