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138 results on '"Fang, Zhifeng"'

14. Optimizing dielectric polarization for electromagnetic wave attenuation via an enhanced Maxwell–Wagner–Sillars effect in hollow carbon microspheres.

Author

Wang, Baojun, Wu, Hao, Hou, Wenxuan, Fang, Zhifeng, Liu, Heqin, Huang, Fangzhi, Li, Shikuo, and Zhang, Hui

Abstract

The rational integration of dielectric components is a promising approach to optimize the Maxwell–Wagner–Sillars effect (MWSE) for developing lightweight and highly efficient electromagnetic wave (EMW) absorbers. However, the controllable modulation of the dielectric polarization relaxation response remains a great challenge, and impedes the further improvement of the absorption properties. Herein, an inside-out Ostwald ripening and phase-evolution strategy is proposed for the preparation of uniform-sized hollow N-doped carbon microspheres with embedded Ni/Ni2P heterojunctions (Ni/Ni2P/CNs). The resulting Ni/Ni2P/CNs microspheres well-integrated the Ni/Ni2P heterojunctions with a hollow carbon skeleton to optimize the impedance matching and the MWSE, thus reinforcing the dielectric polarization relaxation response. Consequently, the fabricated Ni/Ni2P/CNs exhibited superior EMW-absorption performances with a minimum reflection loss of −72.2 dB at a thin matched thickness of 1.7 mm and the absorption bandwidth reached 5.8 GHz. Such remarkable performances exceed most of the previously reported absorbers with a hollow structure. The experimental results and simulation analysis demonstrated that the Ni/Ni2P/CNs microspheres possessed large interior voids, well-defined heterojunctions, and enlarged electron-redistribution regions, which are crucial contributions to optimize the MWSE and strengthen dielectric polarization. This study presents a novel avenue for the controllable design of MWSE-strengthened absorbers and provides a feasible method to reinforce dielectric polarization with balanced conduction loss and polarization loss. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Lactiplantibacillus pentoses CCFM1227 Produces Desaminotyrosine to Protect against Influenza Virus H1N1 Infection through the Type I Interferon in Mice.

Author

Wang, Qianwen, Fang, Zhifeng, Xiao, Yue, Wang, Hongchao, Zhang, Pinghu, Lu, Wenwei, Zhang, Hao, and Zhou, Xiuwen

Abstract

Microbiota-derived desaminotyrosine (DAT) protects the host from influenza by modulating the type I interferon (IFN) response. The aim of this study was to investigate the antivirus effects of a DAT-producing bacteria strain. A comparative genomics analysis and UHPLC Q-Exactive MS were used to search for potential strains and confirm their ability to produce DAT, respectively. The anti-influenza functions of the DAT producer were evaluated using an antibiotic-treated mouse model by orally administering the specific strain before viral infection. The results showed the Lactiplantibacillus pentosus CCFM1227 contained the phy gene and produced DAT by degrading phloretin. In vivo, L. pentosus CCFM1227 re-inoculation increased the DAT level in feces, and protected from influenza through inhibiting viral replication and alleviating lung immunopathology. Furthermore, CCFM1227-derived DAT was positively correlated with the IFN-β level in the lung. The transcriptome results showed that CCFM1227 activated gene expression in the context of the defense response to the virus, and the response to interferon-beta. Moreover, CCFM1227 treatment upregulated the expression of MHC-I family genes, which regulate the adaptive immune response. In conclusion, L. pentosus CCFM1227 exerted antiviral effects by producing DAT in the gut, and this may provide a potential solution for creating effective antiviral probiotics. [ABSTRACT FROM AUTHOR]

Published
2023
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48. Isolation, purification, characterization, and analysis of the antioxidant activity of antioxidant peptides from walnut milk fermented with Lactobacillus paracaseiSMN-LBK

Author

Zhong, Hui, Li, Baokun, Fan, Zhexin, Fang, Zhifeng, Li, Yuhui, Lu, Shiling, Shen, Yuechenfei, Wang, Wenjing, and Zhang, Ruofan

Abstract

Microbial fermentation is an important method to obtain antioxidant peptides. In this study, Lactobacillus paracaseiSMN-LBK was used to ferment biprotein (walnut milk) to enhance the antioxidant capacity of the active peptide. The optimal fermentation process of 5% inoculum, 1:7 plant protein ratio, 37 °C and 12 h resulted in 77.63% ± 0.36% DPPH scavenging, 93.31% ± 0.25% ABTS scavenging and 79.37% ± 0.02% metal ion chelating capacity. The hydrolysis products were classified into three molecular weight classes using an ultrafiltration membrane system. DPAP-3 with a molecular weight of less than 3 kDa had the highest antioxidant activity. DPAP-3 was further separated into three subclasses using gel filtration chromatography. These subclasses were characterized using nano-liquid chromatography-tandem mass spectrometry (NanoLC-MS/MS) and screened by searching https://biochemia.uwm.edu. Four antioxidant peptides were identified using a combination of hydrophobic amino acids, positive ion-charge interactions, and numerical values. Two of these peptides were from animals and one from plants. Their amino acid sequences are as follows PCRGVLLR, IHIPLPRWV, QSKVLPVPQK, and KVLPVPQKA, with molecular docking binding energies of −7.8, −8.3, −7.4, and −7.7 kcal/mol, respectively. The results suggest that fermentation of plant-animal proteins with Lactobacillus paracaseican produce antioxidant peptides that can be used as functional ingredients in food products. This has the potential to conserve animal protein resources.

Published
2024
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