The overapplication of chemical pesticides will cause heavy pollution in water, soil, and foodstuff, and cause irreversible damage to the ecological environment and human health. Therefore, it is imperative to develop a highly sensitive and reliable tool for detecting pesticide residues in the environment. In this work, a novel nopinone-based fluorescent probe THIP-OCP for the detection of parathion-methyl was constructed from BchE inhibition principles. The ester bond in THIP-OCP was hydrolyzed by BchE, leading to the release of the fluorophore THIP-OH and a significant enhancement of the fluorescence signal at 547 nm. However, parathion- methyl could inhibit BchE activity significantly and resulted in fluorescence quenching at 547 nm. Probe THIP-OCP was effectively used to detect BchE and parathion-methyl, and the detection limits were as low as 8.56 U/L and 0.79 mu g/mL, respectively. A portable smartphone-based analysis platform for quantitative and qualitative analysis of parathion-methyl in soil was developed from probe THIP-OCP. This probe can also be used to detect butyrylcholinesterase (BchE) and parathion-methyl in living cells and zebrafish, providing a new tool for monitoring BchE and parathion-methyl in living systems, which is helpful for protecting human life and health. Therefore, the probe THIP-OCP is regarded as a promising tool for monitoring environmental safety and biological health systems.

Understanding the failure process of bottom-saturated loess slopes is of great significance in loess areas where flood irrigation is commonly utilized to alleviate the scarcity of precipitation. In this study, the failure process of a loess slope with an increased groundwater level was recreated and the multiple failure modes of loess landslides were revealed. A centrifugal model test was conducted using a groundwater-recharge device. An intact loess sample retrieved from the Heifangtai Loess Terrace was employed in the test. The model test was monitored using a video recorder, high-speed camera, and soil/pore water pressure sensors, and the results were validated by utilizing an intermittently investigated field landslide. Based on the monitored data and acceleration, the test was divided into three periods: the initial acceleration period with no water inlet (0-40 g), bottom saturation period (40-60 g), and failure occurrence period (60-80 g). The soil/ pore water pressure and degree of deformation were relatively low, with a steadily increasing trend during the first two periods. With the enrichment of the soil water content, retrogressive sliding, deep subsidence, and surface sinkhole failures occurred successively up to areas with relatively high pore water pressure during the last period. The results of the field landslide investigation showed multiple failure modes, as observed in the model test. The results suggest that the coexistence of multiple failure modes could gradually evolve into croplands and promote water infiltration into the deep loess, increasing the groundwater level and accelerating the failure process of the slope. Despite the overall effects of multiple failure patterns on the evolution of the slope, each failure pattern had a relatively independent evolutionary process within a certain area, which could be further analyzed for the early recognition of loess landslides. This study also indicates that the challenges of centrifuge modeling for water-related materials with intact soil samples are the boundary conditions and data monitoring within the model.

Soil disturbance includes the change of stress state and the damage of soil structure. The field testing indices re flect the combined effect of both changes and it is dif ficult to identify the soil structure disturbance directly from these indices. In the present study, the small -strain shear modulus is used to characterize soil structure disturbance by normalizing the effective stress and void ratio based on Hardin equation. The procedure for evaluating soil sampling disturbance in the field and the further disturbance during the subsequent consolidation process in laboratory test is proposed, and then validated by a case study of soft clay ground. Downhole seismic testing in the field, portable piezoelectric bender elements for the drilled sample and bender elements in triaxial apparatus for the consolidated sample were used to monitor the shear wave velocity of the soil from intact to disturbed and even remolded states. It is found that soil sampling disturbance degree by conventional thin -wall sampler is about 30% according to the proposed procedure, which is slightly higher than that from the modi fied volume compression method proposed by Hong and Onitsuka (1998). And the additional soil disturbance induced by consolidation in laboratory could reach about 50% when the consolidation pressure is far beyond the structural yield stress, and it follows the plastic volumetric strain quite well. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).