Biodegradable electrospun fibers as sustained-release carriers of insect pheromones for field trapping of Spodoptera litura (Lepidoptera: Noctuidae).

BACKGROUND: Insect pheromones are highly effective and environmentally friendly, and are widely used in the monitoring and trapping of pests. However, many researchers have found that various factors such as ultraviolet light and temperature in the field environment can accelerate the volatilization of pheromones, thus affecting the actual control effect. In recent years, electrospinning technology has demonstrated remarkable potential in the preparation of sustained carriers. Moreover, the utilization of biodegradable materials in electrospinning presents a promising avenue for the advancement of eco-friendly carriers. RESULTS: In this study, homogeneous and defect-free pheromone carriers were obtained by electrospinning using fully biodegradable polyhydroxybutyrate materials and pheromones of Spodoptera litura. The electrospun fibers with porous structure could continuously release pheromone (the longest can be ≤80 days). They also had low light transmission, hydrophobic protection. More importantly, the pheromone-loaded electrospun fiber carriers showed stable release and good trapping effect in the field. They could trap pests for at least 7 weeks in the field environment without other light stabilizers added. CONCLUSION: Sustained-release carriers constructed by electrospinning and green materials could improve the efficacy of pheromones and ensure environmental friendliness, and provided a tool for the management of S. litura and other pests and sustainable development of agricultural. © 2023 Society of Chemical Industry.

Effect of adhesion force on the height pesticide droplets bounce on impaction with cabbage leaf surfaces.

The relationship between adhesion force and the height drops containing difenoconazole-loaded mesoporous silica nanoparticles (DF-MSNs)/Tween 80 bounce on cabbage leaf surfaces was investigated as a function of Tween 80 concentration. The adhesion force of a pesticide droplet on cabbage leaf surfaces was assessed using a high-sensitivity microelectromechanical balance system and the impact behavior was recorded with a high-speed camera. The height droplets bounced decreased with increasing adhesion force, with a negative correlation between the height of the bouncing drops and adhesion force. Although droplets containing ≥0.06% Tween 80 adhered to the cabbage leaves, the retraction height was still observed to decrease as the adhesion force increased. The experimental results indicate that for cabbage leaf surfaces, the adhesion force has a significant effect on the height drops bounce. The results provide new insights into how researchers can screen for formulations for hydrophobic target crops and how to increase spray adhesion to difficult-to-wet crop leaf surfaces.

Influence of the surface limiting elasticity modulus on the impact behavior of droplets of difenoconazole-loaded mesoporous silica nanoparticles with associated SDS.

The relation between the surface limiting elasticity modulus, ε0, of difenoconazole-loaded mesoporous silica nanoparticle (DF-MSN) formulations with associated SDS and the height of the first returning droplet impacting on cabbage and rice leaf surfaces was investigated. The surface dilational rheology properties were determined by means of surface tension relaxation. The impact of a droplet on the leaf surface was recorded with a high-speed camera. The surface limiting elasticity modulus, ε0, shows differences with different SDS concentrations. A positive correlation between droplet first rebound height and the surface limiting elasticity modulus, ε0, is observed. The pesticide droplet impact on the target leaf surface is a rather complex phenomenon, so the focus of this article is to establish a relationship between the surface limiting elasticity modulus, ε0, and droplet first rebound height. These findings introduce a chemical way to affect the impact behavior of pesticide droplets on target crop leaf surfaces, which may be of particular importance for pesticide spraying and crop protection, especially for hydrophobic and superhydrophobic target crops.

Evaporation kinetics of surfactant solution droplets on rice (Oryza sativa) leaves.

The dynamics of evaporating sessile droplets on hydrophilic or hydrophobic surfaces is widely studied, and many models for these processes have been developed based on experimental evidence. However, few research has been explored on the evaporation of sessile droplets of surfactant or pesticide solutions on target crop leaves. Thus, in this paper the impact of surfactant concentrations on contact angle, contact diameter, droplet height, and evolution of the droplets' evaporative volume on rice leaf surfaces have been investigated. The results indicate that the evaporation kinetics of surfactant droplets on rice leaves were influenced by both the surfactant concentrations and the hydrophobicity of rice leaf surfaces. When the surfactant concentration is lower than the surfactant CMC (critical micelle concentration), the droplet evaporation time is much longer than that of the high surfactant concentration. This is due to the longer existence time of a narrow wedge region under the lower surfactant concentration, and such narrow wedge region further restricts the droplet evaporation. Besides, our experimental data are shown to roughly collapse onto theoretical curves based on the model presented by Popov. This study could supply theoretical data on the evaporation of the adjuvant or pesticide droplets for practical applications in agriculture.

Clinical application of a novel computer-aided detection system based on three-dimensional CT images on pulmonary nodule.

The aim of this study was to investigate the clinical application effects of a novel computer-aided detection (CAD) system based on three-dimensional computed tomography (CT) images on pulmonary nodule. 98 cases with pulmonary nodule (PN) in our hospital from Jun, 2009 to Jun, 2013 were analysed in this study. All cases underwent PN detection both by the simple spiral CT scan and by the computer-aided system based on 3D CT images, respectively. Postoperative pathological results were considered as the "gold standard", for both two checking methods, the diagnostic accuracies for determining benign and malignant PN were calculated. Under simple spiral CT scan method, 63 cases is malignant, including 50 true positive cases and 13 false positive cases from the "gold standard"; 35 cases is benign, 16 true negative case and 19 false negative cases, the Sensitivity 1 (Se1)=0.725, Specificity1 (Sp1)=0.448, Agreement rate1 (Kappa 1)=0.673, J1 (Youden's index 1)=0.173, LR(+)1=1.616, LR(-)1=0.499. Kappa 1=0.673 between the 0.4 and 0.75, has a moderate consistency. Underwent computer-aided detection (CAD) based on 3D CT method, 67cases is malignant, including 62 true positive cases and 7 false positive cases; 31 cases is benign, 24 true negative case and 7 false negative cases, Sensitivity 2 (Se2)=0.899, Specificity2 (Sp2)=0.828, Agreement rate (Kappa 2)=0.877, J2 (Youden's index 2)=0.727, LR(+)2=5.212, LR(-)2=0.123. Kappa 2=0.877 >0.75, has a good consistency. Computer-aided PN detecting system based on 3D CT images has better clinical application value, and can help doctor carry out early diagnosis of lung disease (such as cancer, etc.) through CT images.

Determination of abamectin residues in edible oils by high-performance liquid chromatography with fluorescence detection.

A rapid and simple HPLC-fluorescence detection method has been developed for the determination of abamectin residues in edible oil. Residues are extracted with acetonitrile and by vortexing and then directly derivatized with no need for a time-consuming cleanup step. Trifluoroacetic anhydride and N-methylimidazole were used as derivatizing agents of abamectin. Abamectin was detected and quantitated with fluorescence detection (excitation: 365 nm; emission: 475 nm), and methanol was used as the mobile phase. The LOD was 0.001 mg/kg and the LOQ was 0.003 mg/kg. The recoveries ranged from 86 to 100.4% with satisfactory precision (RSD < 10.1%). This method proved to be sensitive, environmentally friendly, time-saving, and efficient.

Liquid-phase synthesis of cyanuric acid from urea.

The focus of this paper was to identify a cheaper solvent from among diesel fuel, kerosene, sulfolane or a mixture of sulfolane and cyclohexanol for the preparation of cyanuric acid heterocyclization of urea. To obtain a higher yield, the effects of catalyst (sodium, ammonium, calcium and zinc salts) and temperature (160 degrees C to 220 degrees C) on the trimerization of urea were also carefully studied. We established the optimal reaction conditions and further validated them in our scale-up experiments.

[Spectroscopy characteristics of various aluminum phosphates in Al2O3-P2O5-H2O system and its high temperature products].

Various aluminum phosphates were prepared with phosphoric acid and aluminum hydroxide under different conditions. IR, XRD, Raman and SEM were used to study the structure difference and their change in heating process and particle morphology of obtained products and aluminum tripolyphosphate. The results show that the spectral characteristic change of phosphate from H2PO4-, PO4(3-), H2P3O10(3-) and PO3- can be seen when P/Al molar ratio = 3 or the condensation temperature is different. The PO symmetric stretching peaks shift to lower wavenumber and the bands widen along with the extent of polymerization. After aluminum tripolyphosphate is heated, the frequencies of stretching vibrational modes depend on the micro-structure units of phosphate and increase with the extent of polymerization. Both Raman and infrared spectra can characterize the pattern of the hydroxyl stretching vibrations. The laminated thickness of reaction product is increases and laminar boundary is vague until the clinker clew is formed.