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Objective: This study aimed to investigate the pollution of heavy metals in Astragalus membranaceus in the main producing areas of Gansu, and to evaluate the potential health risks of edible Astragalus membranaceus. Methods: The contents of five heavy metal elements Pb, Cd, As, Hg and Cu in Astragalus membranaceus were determined by inductively coupled plasma mass spectrometer （ICP-MS） by random sampling method, and the data were analyzed. Estimated Daily Intake （EDI）, Target Hazard Factor （THQ） and Lifetime Carcinogenicity Risk （LCR） were used for health risk assessment. Results: The average contents of Pb, Cd, As, Hg, and Cu elements in 58 batches of Astragalus membranaceus samples were 0.148, 0.024, 0.139, 0.011 and 4.569 mg/kg, respectively. According to the limited standards stipulated in the 2020 edition of the Chinese Pharmacopoeia, although the detection rate of individual elements was high, but none of them exceeds the standard. The health risk assessment model showed that EDICu＞Pb＞Hg＞Cd, and all less than 1, LCR was also less than 1×10-6. Indicated that the overall level of Astragalus membranaceus samples in this study was safe. Conclusion: The content of five heavy metals in Astragalus membranaceus produced in Gansu will not cause potential risks to the health of adults and children, and there is no potential carcinogenic risk.

Malachite green (MG), a triphenylmethane dye, is used in the aquaculture industry as a disinfectant and insect repellent due to its potent bactericidal and pesticidal properties. However, its use poses potential environmental and health risks. This study analyzed and designed two haptens using computer simulation. Serum data confirmed the feasibility of introducing an arm at the dimethylamine group. Subsequently, a highly selective monoclonal antibody strain was successfully prepared based on the hapten. After optimizing the working conditions of indirect competitive enzyme-linked immunosorbent assay (IC-ELISA), the IC50 value was 0.83 ng/mL, with a detection limit (IC10) of 0.08 ng/mL and a linear range of 0.19–3.52 ng/mL. The developed monoclonal antibody exhibited a crossover rate of less than 0.1% with other similar structures and can be used to establish an immunoassay. [ABSTRACT FROM AUTHOR]

The Gleeble-3500 thermal simulation tester was used to perform hot deformation behavior on the extruded AZ40 Mg alloy to analyze the trend of the true stress-strain curve after compression and to obtain the influence of the flow stress on the deformation temperature and strain rate. Subsequently, the constitutive equation was constructed for extruded AZ40 alloy based on the hyperbolic-sine relationship, and the thermal processing map of extruded AZ40 alloy was established based on the dynamic material model (DMM), thereby estimating the processing range of extruded AZ40 alloy. The results show that the rheological curve of extruded AZ40 alloy is characterized by obvious dynamic recrystallization. Furthermore, during the compression process, the peak stress of extruded AZ40 alloy decreases with the increase of deformation temperature, while increases with the increase of strain rate. Moreover, the proportion of dynamic recrystallized grains (DRGs) decreases with the increase of the strain rate under the same deformation temperature condition; while the DRGs size increases with the increase of the deformation temperature under the same strain rate condition. The coarse uncrystallized grains show obvious crystallographic orientations of 〈1010〉‖ND and 〈2110〉‖ND, while crystallographic orientation of DRGs is random distributed. Finally, through thermal processing map and tissue analysis, the optimal processing window was identified as T=573 K, $\dot \varepsilon $=0.1 s-1.

The microstructure of as-cast Mg-6Zn-xCe alloy was investigated by optical microscope (OM), X-ray diffraction (XRD), scanning election microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM)and the changing rule of thermal conductivity with the content of Ce was investigated using the flash method. The results show that Mg-6Zn alloy is mainly composed of α-Mg and Mg7Zn3 phases. The ternary phase Ce5 (Mg,Zn)41 which is mainly distributed between grain boundaries and dendrites appears in the alloy after the addition of the rare earth element Ce, and the appearance of ternary phase has an inhibitory effect on Mg7Zn3 phase. The content of eutectic structure is increased by the addition of Ce, and the distribution continuity is improved with the increase of Ce content. The thermal conductivity of the alloy is decreased with the increase of Ce content, which may be caused by the increase of volume fraction, more continuous distribution of eutectic structure in the alloy, the enhanced electron scattering, the extended electron conduction paths and the increased thermal resistance, ultimately the thermal conductivity of the alloy is reduced.