Laccase immobilized on amino-functionalized magnetic Fe3O4-SiO2 core-shell material for 2,4-dichlorophenol removal.

In this study, an amino-functionalized magnetic silica microsphere material (Fe3O4-SiO2-NH2) was prepared. Using glutaraldehyde as a cross-linking agent, Trametes versicolor laccase was adsorbed-covalently bonded and immobilized on the material to prepare Laccase @ Fe3O4-SiO2. In addition, the materials were characterized and analysed by SEM, TEM, XRD, FT-IR and VSM. Finally, the thermal inactivation dynamics of immobilized laccase in polar/non-polar/toxic systems and the adsorption and degradation of 2,4-DCP were studied. The results showed that Laccase @ Fe3O4-SiO2 under the optimal conditions (pH 6, temperature 65°C, initial concentration of 2,4-DCP 10 mg/L), the removal rate was as high as 81.6%. Moreover, compared with free laccase, immobilized laccase had good tolerance under low pH and high-temperature conditions, and storage stability was also greatly improved. After repeated use for 7 times, Laccase @ Fe3O4-SiO2 can still maintain 59% removal rate of 2,4-DCP, which gives it the potential for industrial applications.

Improved NLMS-based adaptive denoising method for ECG signals.

BACKGROUND: Traditional least mean square algorithm (LMS) tends to converge faster and thus the larger the steady-state error of the algorithm. OBJECTIVE: In order to solve this issue, an improved adaptive normalized least mean square (NLMS) ECG signal denoising algorithm is proposed through utilizing the NLMS and the least mean square algorithm with added momentum term (MLMS). METHODS: The algorithm firstly performs LMS adaptive filtering on the original ECG signal. Then, the algorithm uses the relative error of the prior error signal and the posterior error signal before and after filtering to adaptively determine the iteration step factor. Finally, the expected error is set to determine whether the denoising meets the expected requirements. This method is applied to the MIT-BIH ECG database established by the Massachusetts Institute of Technology. RESULTS: Experimental results have shown that the proposed algorithm can achieve good denoising for the target signal, and the average signal to noise ratio (SNR) of the proposed method is 17.6016, the RMSE is only 0.0334, and the average smoothness index R is only 0.0325. CONCLUSION: The proposed algorithm effectively removes the original ECG signal noise, and improves the smoothness of the signal the denoising efficiency.

Inhibition of experimental allergic rhinitis by the n-butanol fraction from the anomalous fruits of Gleditsia sinensis.

This study was conducted to clarify the effect of the n-butanol fraction from the anomalous fruits of Gleditsia sinensis LAM. (NBGS) on experimental allergic rhinitis. NBGS (100, 200, 400 mg/kg, p.o.) dose-dependently inhibited nasal symptoms (sneezing and nasal rubbing) and dye leakage induced by antigen challenge into the nasal cavity of actively sensitized rats. Significant effects were observed at doses of 200 and 400 mg/kg. NBGS (200, 400 mg/kg) also showed a clear inhibition of sneezing and an inhibitory tendency on nasal rubbing induced by histamine in normal rats. At 400 mg/kg, it significantly reduced dye leakage induced by histamine into the nasal cavity of rats. Terfenadine (10 mg/kg, p.o.), an antihistaminic drug, clearly inhibited the nasal symptoms and the amount of dye leakage induced by antigen or histamine. Furthermore, NBGS significantly reduced in vitro histamine release from rat peritoneal mast cells triggered by compound 48/80 at concentrations of 30 and 100 microg/ml. These results suggest that NBGS may be clinically effective in alleviating the nasal symptoms of allergic rhinitis, probably by inhibiting both histamine release from mast cells and nasal vascular permeability.