Quantitative proteomics based on TMT revealed the response of PK15 cells infected PEDV wild strain.

Porcine epidemic diarrhea (PED), caused by porcine epidemic diarrhea virus (PEDV), is an acute and highly contagious enteric disease with a high mortality rate in suckling piglets. Identification of proteins associated with PEDV infection may provide insights into the pathogenesis of this viral disease. In this study, we employed tandem mass tag (TMT) quantitative protein analysis to investigate proteomic changes in PK15 cells following PEDV infection, and differential protein expression profiles were obtained at 0 h, 24 h, and 48 h post-infection. Overall, a total of 6330 proteins were identified. Applying criteria for fold change >1.5 < 0.67 and p-values <0.05 resulted in the identification of 59 up-regulated proteins and 103 down-regulated proteins that exhibited significant alterations in the H24 group compared to the H0 group. The H48 group demonstrated significant upregulation of 110 proteins and downregulation of 144 proteins compared to the H0 group; additionally, there were also 10 upregulated and 30 downregulated proteins in the H48 group when compared to the H24 group. These differentially expressed proteins (DEPs) were involved in immune response regulation, signal transduction, lipid transport and metabolism processes as well as cell apoptosis pathways. Based on these DEPs, we propose that PEDV may disrupt signal transduction pathways along with lipid transport and metabolism processes leading to maximal viral replication, it may also trigger inflammatory cascades accordingly. These findings could provide valuable information for elucidating specific pathogenesis related to PEDV infection while contributing towards developing new antiviral strategies.

In Situ Visualization and Mechanistic Understandings on Facet-Dependent Atomic Redispersion of Platinum on CeO2.

Redispersion is an effective method for regeneration of sintered metal-supported catalysts. However, the ambiguous mechanistic understanding hinders the delicate controlling of active metals at the atomic level. Herein, the redispersion mechanism of atomically dispersed Pt on CeO2 is revealed and manipulated by in situ techniques combining well-designed model catalysts. Pt nanoparticles (NPs) sintered on CeO2 nano-octahedra under reduction and oxidation conditions, while redispersed on CeO2 nanocubes above ∼500 °C in an oxidizing atmosphere. The dynamic shrinkage and disappearance of Pt NPs on CeO2 (100) facets was directly visualized by in situ TEM. The generated atomically dispersed Pt with the square-planar [PtO4]2+ structure on CeO2 (100) facets was also confirmed by combining Cs-corrected STEM and spectroscopy techniques. The redispersion and atomic control were ascribed to the high mobility of PtO2 at high temperatures and its strong binding with square-planar O4 sites over CeO2 (100). These understandings are important for the regulation of atomically dispersed platinum catalysts.

Transcriptomic analysis reveals impact of gE/gI/TK deletions on host response to PRV infection.

BACKGROUND: Pseudorabies virus (PRV) causes substantial losses in the swine industry worldwide. Attenuated PRV strains with deletions of immunomodulatory genes glycoprotein E (gE), glycoprotein I (gI) and thymidine kinase (TK) are candidate vaccines. However, the effects of gE/gI/TK deletions on PRV-host interactions are not well understood. METHODS: To characterize the impact of gE/gI/TK deletions on host cells, we analyzed and compared the transcriptomes of PK15 cells infected with wild-type PRV (SD2017), PRV with gE/gI/TK deletions (SD2017gE/gI/TK) using RNA-sequencing. RESULTS: The attenuated SD2017gE/gI/TK strain showed increased expression of inflammatory cytokines and pathways related to immunity compared to wild-type PRV. Cell cycle regulation and metabolic pathways were also perturbed. CONCLUSIONS: Deletion of immunomodulatory genes altered PRV interactions with host cells and immune responses. This study provides insights into PRV vaccine design.

Engineering Cf /ZrB2 -SiC-Y2 O3 for Thermal Structures of Hypersonic Vehicles with Excellent Long-Term Ultrahigh Temperature Ablation Resistance.

Ultrahigh temperature ceramic matrix composites (UHTCMCs) are critical for the development of high Mach reusable hypersonic vehicles. Although various materials are utilized as the thermal components of hypersonic vehicles, it is still challenging to meet the ultrahigh temperature ablation-resistant and reusability. Herein, the Y2 O3 reinforced Cf /ZrB2 -SiC composites are designed, which demonstrates near-zero damage under long-term ablation at temperatures up to 2500 °C for ten cycles. Notably, the linear ablation rate of the composites (0.33 µm s-1 ) is over 24 times better than that of the conventional Cf /C-ZrC at 2500 °C (8.0 µm s-1 ). Moreover, the long-term multi-cycle ablation mechanisms of the composites are investigated with the assistance of DFT calculations. Especially, the size effect and the content of the Zr-based crystals in the oxide layer fundamentally affect the stability of the oxide layer and the ablation properties. The ideal component and structure of the oxide layer for multi-cycle ablation condition are put forward, which can be obtained by controlling the Y2 O3 /ZrB2 mole ratio and establishing Y-Si-O - t-Zr0.9 Y0.1 O1.95 core-shell nano structure. This work proposes a new strategy for improving the long-term multi-cycle ablation resistance of UHTCMCs.

RSL3 Inhibits Porcine Epidemic Diarrhea Virus Replication by Activating Ferroptosis.

Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that induces diarrhea and death in neonatal piglets, resulting in substantial economic losses to the global swine industry. The mechanisms of PEDV infection and the roles of host factors are still under exploration. In this study, we used the ferroptosis pathway downstream target activator (1S,3R)-RSL3 compound as a starting point, combined with the interactions of N-acetylcysteine and deferoxamine, to elucidate the effects of a series of compounds on PEDV proliferation. We also established glutathione peroxidase 4 (GPX4) gene overexpression to further elucidate the relationship between the ferroptosis pathway and PEDV. (1S,3R)-RSL3 inhibited PEDV replication in Vero cells, while N-acetylcysteine and deferoxamine promoted its proliferation. In addition, (1S,3R)-RSL3 mainly affected the replication stage of PEDV. Overexpression of GPX4 promoted PEDV proliferation, indicating that the ferroptosis pathway could influence PEDV replication in Vero cells. This study focused on the mechanism of (1S,3R)-RSL3 inhibition on PEDV, laying the foundation for exploring the pathogenic mechanisms of PEDV and drug development.

Quantitative Analysis of the Interface between Titanium Dioxide Support and Noble Metal by Electron Energy Loss Spectroscopy.

The interface structure of supported catalysts plays a significant role in the strong metal-support interactions (SMSI). However, it remains limited on interpreting interface structures, thus affecting the understanding of SMSI origin and impact on catalytic performance. Herein, electronic energy loss spectroscopy was adopted to characterize the interface microstructures of Pt/TiO2 materials. After high-temperature reduction processing, it was observed that the coating on the surface of the Pt metal particles was TiOx. Then, based on Gaussian function fitting, an effective and valid method was established for quantitative analysis on Ti L edge loss spectrum. This method allowed us to accurately determine the stoichiometric number of TiOx phases. In order to probe the classical phenomenon of strong metal-support interactions in more detail, we also discussed and analyzed the origin of TiOx and its effect on the electronic structure of the material using density functional theory calculations. The structure of surfaces and interfaces as well as the chemical evolution of supported catalysts on a microscale have been revealed, thereby providing a new analysis method and research perspectives for the future study of metal-support interactions.

Multifunctional Hierarchical Metamaterial for Thermal Insulation and Electromagnetic Interference Shielding at Elevated Temperatures.

The custom design of lightweight cellular materials is widely concerned due to effectively improved mechanical properties and functional applications. However, the strength attenuation and brittleness behavior hinder honeycomb structure design for the ceramic monolith. Herein, the ceramic matrix composite metamaterial (CCM) with a negative Poisson's ratio and high specific strength, exhibiting superelasticity, stability, and high compressive strength, is customized by combining centripetal freeze-casting and hierarchical structures. CCM maintains a negative Poisson's ratio response under compression with the lowest value reaching -0.16, and the relationship between CCM's specific modulus and density is E ∼ ρ1.3, which indicates the mechanical metamaterial characteristic of high specific strength. In addition to the extraordinary mechanical performance endowed by hierarchical structures, the CCM exhibits excellent thermal insulation and electromagnetic interference shielding properties, in which the thermal conductivity is 30.62 mW·m-1·K-1 and the electromagnetic interference (EMI) shielding efficiency (SE) reaches 40 dB at room temperature. The specific EMI shielding efficiency divided by thickness (SSE/t) of CCM can reach 9416 dB·cm2·g-1 at 700 °C due to its stability at elevated temperatures, which is 100 times higher than that of traditional ceramic matrix composites. Moreover, the designed hierarchical structure and metamaterial properties provide a potential scheme to implement cellular materials with collaborative optimization in structure and function.

Comparative transcriptomic analysis of PK15 cells infected with a PRV variant and the Bartha-K/61 vaccine strain.

Introduction: Pseudorabies virus (PRV) is a herpesvirus that can infect domestic animals, such as pigs, cattle and sheep, and cause fever, itching (except pigs), and encephalomyelitis. In particular, the emergence of PRV variants in 2011 have resulted in serious economic losses to the Chinese pig industry. However, the signaling pathways mediated by PRV variants and their related mechanisms are not fully understood. Methods: Here, we performed RNA-seq to compare the gene expression profiling between PRV virulent SD2017-infected PK15 cells and Bartha-K/61-infected PK15 cells. Results: The results showed that 5,030 genes had significantly different expression levels, with 2,239 upregulated and 2,791 downregulated. GO enrichment analysis showed that SD2017 significantly up-regulated differentially expressed genes (DEGs) were mainly enriched in the binding of cell cycle, protein and chromatin, while down-regulated DEGs were mainly enriched in ribosomes. KEGG enrichment analysis revealed that the pathways most enriched for upregulated DEGs were pathways in cancer, cell cycle, microRNAs in cancer, mTOR signaling pathway and autophagy-animal. The most down-regulated pathways of DEGs enrichment were ribosome, oxidative phosphorylation, and thermogenesis. These KEGG pathways were involved in cell cycle, signal transduction, autophagy, and virus-host cell interactions. Discussion: Our study provides a general overview of host cell responses to PRV virulent infection and lays a foundation for further study of the infection mechanism of PRV variant strain.

Erastin inhibits porcine epidemic diarrhea virus replication in Vero cells.

Background: Porcine epidemic diarrhea virus (PEDV), an intestinal pathogenic coronavirus, has caused significant economic losses to the swine industry worldwide. At present, there are several treatment methods, but there is still a lack of clinically effective targeted drugs, new antiviral mechanisms and drugs need to be explored. Methods: In this study, we established a model of erastin versus ferrostatin-1 treatment of Vero cells, and then detected virus proliferation and gene expression by RT-qPCR through PEDV infection experiments. Results: We demonstrated for the first time that erastin significantly inhibited the replication of PEDV upon entry into cells; Vero treated with erastin significantly regulated the expression of three genes, NRF2, ACSL4 and GPX4, notably erastin regulated the expression of these three genes negatively correlated with the expression induced by PEDV virus infection. Conclusions: Since NRF2, ACSL4 and GPX4 are classical Ferroptosis genes, this study speculates that erastin may inhibit the replication of PEDV in Vero cells in part through the regulation of ferroptosis pathway, and erastin may be a potential drug for the treatment of PEDV infection.

Tailoring centripetal metamaterial with superelasticity and negative Poisson's ratio for organic solvents adsorption.

Graphene metamaterials with a radial-like structure and negative Poisson's ratio (NPR) were assembled using a unique centripetal freezing technique. Driven by the centripetal temperature gradient, ice crystals were grown toward the center of an aqueous graphene dispersion and form a radially arranged skeleton. A reentrant structure was formed at the diagonal of the monolith as the ice crystals sublimate. The obtained centripetal graphene metamaterial (CGM) was endowed with NPR response. CGM maintained NPR under 50% compression, which reached a minimum (-0.18) at 10% strain. After 50 compressive cycles at 50% strain, CGM retained approximately 96% of the original compressive strength. The radial channels endowed CGM with fast absorption kinetics, and the NPR response effectively accommodated the damage caused by volume shrinkage during repeated adsorption-regeneration cycles. This strategy is an effective method for achieving NPR response and improving the mechanical properties of porous materials.

Van der Waals ferromagnetic Josephson junctions.

Superconductor-ferromagnet interfaces in two-dimensional heterostructures present a unique opportunity to study the interplay between superconductivity and ferromagnetism. The realization of such nanoscale heterostructures in van der Waals (vdW) crystals remains largely unexplored due to the challenge of making atomically-sharp interfaces from their layered structures. Here, we build a vdW ferromagnetic Josephson junction (JJ) by inserting a few-layer ferromagnetic insulator Cr2Ge2Te6 into two layers of superconductor NbSe2. The critical current and corresponding junction resistance exhibit a hysteretic and oscillatory behavior against in-plane magnetic fields, manifesting itself as a strong Josephson coupling state. Also, we observe a central minimum of critical current in some JJ devices as well as a nontrivial phase shift in SQUID structures, evidencing the coexistence of 0 and π phase in the junction region. Our study paves the way to exploring sensitive probes of weak magnetism and multifunctional building-blocks for phase-related superconducting circuits using vdW heterostructures.

Novel Graphene Planar Architecture with Ultrahigh Stretchability and Sensitivity.

Graphene has attracted increasing attention for strain sensing due to its unique electrical and mechanical properties by tailoring and assembling functional macrostructures with a well-defined configuration. Here a novel graphene-based planar network (GPN) with highly stretchable strain sensing is developed by direct ink writing. The integrated and regulated structure of GPN indicates an excellent response sensitivity and cyclic stability to various strain modes compared with the traditional graphene-based woven fabric (GWF) structure. An equivalent resistance network is introduced to analyze the resistance change mechanism and fracture failure mode of the network structures, in which the difference can be mainly attributed to the interfacial resistance at the crosspoints of the crossed ribbons. The tunable and interconnected GPN shows a significant difference in the response sensitivity under stretching strain in different directions, and the relative resistance change is up to 20 and 3 in horizontal and vertical directions after 1000 cycles for a 20% stretching strain, respectively, which can be explained by the transformation of the stretching mode from macro-structural stretching to micromaterial stretching. The controllable fabrication of GPN can be utilized not only for the detection of full-range human activities but monitoring external stress distribution in real-time by integration.

Bioinspired nanocomposites film with highly-aligned silicon carbide nanowires and polyvinyl alcohol for mechanical and thermal anisotropy.

This work reports a bioinspired anisotropic nanocomposite by polar solution assisted mechanical stretching method, consisting of polyvinyl alcohol (PVA) and silicon carbide nanowires (SiCNWs) with aligned morphology in one direction. Inspired by the structural mimicry of myofibers, in which the uniaxial mechanical property of materials can be improved evidently, highly-aligned SiCNWs and PVA chains that interact using intermolecular force can be obtained. Hysteresis is observed and reversible deformation occurs while tensile-relaxation cycles are applied to the 100% stretched SiCNWs/PVA nanocomposites. The nanocomposites exhibit excellent properties and the tensile strength of 100% stretched SiCNWs/PVA nanocomposites is 188.30 ± 4.2 MPa and elastic modulus is 6.95 GPa, which are increased by 421.90% and 581.37% compared with pure PVA. Finite element simulation of fracture mechanism shows good agreement with the experimental results. An improvement of thermal conductivity is also achieved in well-aligned SiCNWs/PVA. The work imitates the structure of mammal muscle and also has great potential for the macroscopic application of one-dimensional nanomaterials as super flexible heat dissipation materials.

Synthesis and characterization of nano-crystalized HfC based on an aqueous solution-derived precursor.

Nano-crystalized HfC was successfully synthesized based on an aqueous solution-derived precursor using hafnium tetrachloride and sucrose as raw materials. The precursor can be converted to pure phase HfC after pyrolysis at ∼600 °C and subsequent carbothermal reduction reaction at ∼1600 °C, with a ceramic yield of around 46.3%. Reaction mechanisms of the synthesis process are revealed based on FT-IR, TG-DSC, TEM analysis and thermodynamic calculations, etc. The obtained HfC nanoparticles possess an equiaxial shape with an average particle size of ∼73 nm. Oxygen content of the as-synthesized HfC powders is as low as 0.64 wt%, which exists in the form of an amorphous Hf-O-C thin layer covering the surface of the HfC particles. This feasible and promising method for HfC particle synthesis is believed to be suitable for the fabrication of continuous fibers reinforced HfC ceramic matrix composites.

Fabrication of PPy Nanosphere/rGO Composites via a Facile Self-Assembly Strategy for Durable Microwave Absorption.

Traditional magnetic metal and alloy materials suffer from easy oxidation and high density, which hinders their practical application as high-performance microwave absorbers. Lightweight and durability have become new goals in the fabrication of the next generation of microwave absorbers. Herein, we report the synthesis of polypyrrole (PPy) nanosphere/reduced graphene oxide (rGO) composites through chemical reduction of self-assembly PPy nanosphere/GO hybrids. PPy nanospheres and GO are integrated effectively by π⁻π interaction of dual conjugated systems. When the mass ratio of PPy nanospheres to rGO is 0.6:1, the resultant composite, PPy/rGO-0.6, presents comparable/superior reflection loss characteristics to those magnetic metals and their related graphene-based composites in previous studies. Electromagnetic analysis reveals that well-matched characteristic impedance, multiple polarization loss, and good conductivity loss are, together, responsible for the excellent microwave absorption performance of PPy/rGO-0.6. More importantly, PPy/rGO-0.6 also exhibits good microwave absorption after being treated at 423 K for a long time. This work provides a new idea for designing and preparing a high-performance microwave absorber with lightweight and durable features.