This paper aims to improve the biological nitrogen removal performance by using magnetic polystyrene composite microparticles (PS@Fe 3 O 4 ). Three types of PS@Fe 3 O 4 with different surface morphologies were prepared by in-situ emulsion polymerization . Then, the optimum was creatively used as a biofilm carrier to form magnetic activated sludge (MAS) in lab-scale reactors. Compared to the conventional activated sludge , the utilization of PS@Fe 3 O 4 accelerated the sludge settling velocity to 0.76 m/h. In addition, the ammonium nitrogen removal, total nitrogen removal and simultaneous nitrification and denitrification improved by 7.08%, 24.27% and 19.53%, respectively. The dissolved oxygen concentration and pH were observed to reveal the effect of PS@Fe 3 O 4 on the nitrogen removal process. Based on microbial community analysis, there were more nitrifying and denitrifying bacteria in the MAS. Therefore, the novel developed PS@Fe 3 O 4 can be a promising utilization material as a biofilm carrier for biological wastewater treatment .
Liuying He,Xiao Wang,Junyu Chen,Yuze Li,Liping Wang,Caiqiao Xiong,Zongxiu Nie
Liver cancer (LC) is the third frequent cause of death worldwide, so early diagnosis of liver cancer patients is crucial for disease management. Herein, we applied NH2-coated polystyrene@Fe3O4 magnetic beads (PS@Fe3O4–NH2 MBs) as a matrix material in laser desorption/ionization mass spectrometry (LDI-MS). Rapid, sensitive, and selective metabolic profiling of the native biofluids was achieved without any inconvenient enrichment or purification. Then, based on the selected m/z features, LC patients were discriminated from healthy controls (HCs) by machine learning, with the high area under the curve (AUC) values for urine and serum assessments (0.962 and 0.935). Moreover, initial-diagnosed and subsequent-visited LC patients were also differentiated, which indicates potential applications of this method in early diagnosis. Furthermore, among these identified compounds by FT-ICR MS, the expression level of some metabolites changed from HCs to LCs, including 29 and 12 characteristic metabolites in human urine and serum samples, respectively. These results suggest that PS@Fe3O4–NH2 MBs-assisted LDI-MS coupled with machine learning is feasible for LC clinical diagnosis.
African swine fever virus (ASFV) is a highly infectious and pathogenic DNA virus with a mortality rate of nearly 100%. Here, we developed a flexible biosensor based on a AgNWs/hydrogel/PS(polystyrene)/Fe 3 O 4 composite film for the detection of ASFV P72 protein gene fragments. A large number of carboxyl groups in the hydrogel provide modification sites for capture probes (cp) simplifying the preparation process of the biosensor. Combined with the excellent magnetic properties of Fe 3 O 4 , the excellent electrical conductivity of silver nanowires (AgNWs) and the unique optical properties of two-dimensional photonic crystals (2DPC), the flexible biosensor can convert biological signals into optical signals and electrical signals, and the micro-deformation of the film can be verified by simple optical methods. In order to improve the sensitivity, we introduce Fe 3 O 4 and apply an external magnetic field to amplify the thin film micro-deformation. The concentration of P72 protein gene fragment and the relative change rate of resistance showed a good linear relationship, and the linear equation is y = − 0.00126x − 0.31729; the detection limit (LOD) is as low as 0.208 μM. The composite film was used to detect real serum samples, and the recovery of the composite film fluctuated in the range 91.89 to 103.19%, indicating that the composite film has practical application potential in clinical detection of ASFV. In addition, the biosensor also shows good biocompatibility, stability, and specificity. Graphical
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