Inner Mongolia University

Adjusting the selectivity of the oxygen reduction reaction (ORR) is crucial for energy technologies: the four-electron (4e^-) transfer enables the operation of fuel cells and metal-air batteries, while the two-electron (2e^-) reduction promotes the production of hydrogen peroxide (H₂O₂). However, achieving precise control over the catalytic ORR pathways remains a significant challenge. In this study, a feasible solution of tailoring differential pyrolysis was adopted to regulate the ORR selectivity of FeMn-based catalysts. Notably, iron (Fe)-doped Mn₂O₃ nanoparticles loaded on boron (B) and nitrogen (N) co-doped carbon nanosheet (FMO-BNC), prepared by rapid heating (10 °C/min) within the temperature range of 310-400 °C, follows a 2e^- transfer pathway, selectively generating H₂O₂ with a yield of 84.4 %. In contrast, dual-atom FeMn grown on B and N co-doped carbon (SAFM-BNC), synthesized by rapid heating (10 °C/min) in the range of 400-900 °C, facilitates a 4e^- transfer route, exhibiting a half-wave potential (E_1/2 = 0.87 V) comparable to that of commercial Pt/C. The combination of experimental and simulation results indicates that differential pyrolysis modulates the active sites of the catalyst, optimizing the energetics of intermediates to achieve site-dependent ORR selectivity.

Macrophages have both anti-tumor and pro-tumor effects. Time delay is commonly observed in real systems, yet its impact on tumor-macrophage dynamics remains unclear. This paper develops a new tumor-macrophage model with time delay. The model describes the interactions between tumor cells (T), the classically activated macrophages (M1), the alternatively activated macrophages (M2), and the inactive macrophages (M0). The system's solution is computed, and equilibrium stability is analyzed. The existence of Hopf bifurcation is subsequently established. There exists bifurcating periodic solutions near the internal equilibrium, showing tumor cells and macrophages can coexist in the long term, as well as the potential for tumor relapse. Furthermore, the normal form and center manifold theorem are utilized to study the nature of Hopf bifurcation. Sensitivity analysis highlights the effect of parameters on tumor population dynamics. Numerical simulations validate the theory, elaborating the model can serve as a useful tool for tumor system analysis.

Live herpesvirus-vectored vaccines are critical in veterinary medicine, but they can sometimes offer insufficient protection due to suboptimal antigen expression or localization. Encephalomyocarditis virus (EMCV) is a significant zoonotic threat, with VP1 protein as a key immunogen on its capsid. To enhance immunogenicity, we explored the use of recombinant pseudorabies virus (rPRV) as a vaccine vector against EMCV. In silico analysis indicated that fusing VP1 with US9 enhances the formation of a type II transmembrane heterodimer. We constructed six rPRV groups expressing different VP1 variants and found that VP1 fused with US9's C-terminal (US9-VP1) enhances VP1's membrane localization and its incorporation into the PRV envelope, unlike wild-type VP1. Immunogold electron microscopy illustrated that rPRV with deleted US8 and US9, supplemented with US8 regulatory sequence (rΔ89-U9VP1), improved VP1 incorporation into the viral envelope. Post-immunization, only rΔ89-U9VP1 provided 100% protection against EMCV in mice and induced high levels of virus-neutralizing antibodies in piglets. Additionally, rPRV expressing VP1 stimulated robust T-cell responses, as demonstrated by flow cytometry and ELISpot assays. This study introduces rPRV as a potential EMCV vaccine, demonstrating that the selection of the US9 C-terminal domain and US8 regulatory sequence significantly enhances the presentation of heterologous antigens, improving vaccine efficacy.