Correlation-driven topological phase transition in 2D valleytronic materials: a mini-review.

Electronic correlation combined with spin-orbit coupling (SOC) may have a significant impact on the physical properties of two-dimensional (2D) transition metal magnetic compounds. Moreover, magnetic anisotropy (MA) is very important in determining magnetic, ferrovalley (FV) and topological properties of these 2D systems. Based on a density-functional theory (DFT) + U approach, it is found that the electronic correlation can induce topological phase transition in some special 2D valleytronic materials (for example FeCl2 and VSi2P4) with out-of-plane MA, and a novel valley-polarized quantum anomalous Hall insulator (VQAHI) and half-valley-metal (HVM) can be produced. These topological phase transitions are connected with a sign-reversible Berry curvature and band inversion between dxy/dx2-y2 and dz2 orbitals. However, for in-plane MA, the FV and nontrivial topological properties will be suppressed. For a given material, the correlation strength is fixed, but these novel electronic states and topological phase transitions can still be exhibited by strain in practice. The mini-review sheds light on the possible role of correlation effects in some special 2D valleytronic materials.

Janus monolayer ScXY (X≠Y = Cl, Br and I) for piezoelectric and valleytronic application: a first-principle prediction.

Coexistence of ferromagnetism, piezoelectricity and valley in two-dimensional (2D) materials is crucial to advance multifunctional electronic technologies. Here, Janus ScXY (X≠Y = Cl, Br and I) monolayers are predicted to be piezoelectric ferromagnetic semiconductors with dynamical, mechanical and thermal stabilities. They all show an in-plane easy axis of magnetization by calculating magnetic anisotropy energy (MAE) including magnetocrystalline anisotropy energy and magnetic shape anisotropy energy. The MAE results show that they intrinsically have no spontaneous valley polarization. The predicted piezoelectric strain coefficientsd11andd31(absolute values) are higher than ones of most 2D materials. Moreover, thed31(absolute value) of ScClI reaches up to 1.14 pm V-1, which is highly desirable for ultrathin piezoelectric device application. To obtain spontaneous valley polarization, charge doping are explored to tune the direction of magnetization of ScXY. By appropriate hole doping, their easy magnetization axis can change from in-plane to out-of-plane, resulting in spontaneous valley polarization. Taking ScBrI with 0.20 holes per f.u. as an example, under the action of an in-plane electric field, the hole carriers of K valley turn towards one edge of the sample, which will produce anomalous valley Hall effect, and the hole carriers of Γ valley move in a straight line. These findings could pave the way for designing piezoelectric and valleytronic devices.

Endothelial cell-derived MMP19 promotes pulmonary fibrosis by inducing E(nd)MT and monocyte infiltration.

BACKGROUND: Matrix metalloproteinases (MMPs) play important roles in remodeling the extracellular matrix and in the pathogenesis of idiopathic pulmonary fibrosis (IPF). MMP19, which is an MMP, was significantly upregulated in hyperplastic alveolar epithelial cells in IPF lung tissues and promoted epithelial-mesenchymal transition (EMT). Recent studies have demonstrated that endothelial-to-mesenchymal transition (E(nd)MT) contributes to pulmonary fibrosis. However, the role of MMP19 in pulmonary vascular injury and repair and E(nd)MT remains unclear. METHODS: To determine the role of MMP19 in E(nd)MT and pulmonary fibrosis. MMP19 expressions were determined in the lung endothelial cells of IPF patients and bleomycin (BLM)-induced mice. The roles of MMP19 in E(nd)MT and endothelial barrier permeability were studied in the MMP19 cDNA-transfected primary human pulmonary microvascular endothelial cells (HPMECs) and MMP19 adenoassociated virus (MMP19-AAV)-infected mice. The regulatory mechanism of MMP19 in pulmonary fibrosis was elucidated by blocking its interacting proteins SDF1 and ET1 with AMD3100 and Bosentan, respectively. RESULTS: In this study, we found that MMP19 expression was significantly increased in the lung endothelial cells of IPF patients and BLM-induced mice compared to the control groups. MMP19 promoted E(nd)MT and the migration and permeability of HPMECs in vitro, stimulated monocyte infiltration into the alveolus, and aggravated BLM-induced pulmonary fibrosis in vivo. SDF1 and Endothelin-1 (ET1) were physically associated with MMP19 in HPMECs and colocalized with MMP19 in endothelial cells in IPF patient lung tissues. AMD3100 and bosentan alleviated the fibrosis induced by MMP19 in the BLM mouse model. CONCLUSION: MMP19 promoted E(nd)MT by interacting with ET1 and stimulated monocyte infiltration into lung tissues via the SDF1/CXCR4 axis, thus aggravating BLM-induced pulmonary fibrosis. Vascular integrity regulated by MMP19 could be a promising therapeutic target for suppressing pulmonary fibrosis. Video abstract.

Genome-wide DNA methylation dynamics in carbon tetrachloride-induced mice liver fibrosis.

Objectives: Many persistent harmful stimuli can result in chronic liver diseases, which lead to about 2 million deaths per year in the whole world. Liver fibrosis was found to exist in all kinds of chronic liver diseases. Many studies suggested that DNA methylation was associated with the pathogenesis of liver fibrosis. This study aimed to quantitatively detect DNA methylation changes in the whole genome in fibrotic liver tissues of mice. Materials and Methods: Liver fibrosis was induced by intraperitoneal injection of carbon tetrachloride (CCl4) for 4 weeks. A genome-wide methylome analysis was performed using 850K BeadChips assays. The methylation status of 27 CpG dinucleotides located in 3 genes was detected by pyrosequencing to confirm chip data accuracy, and mRNA expressions of these 3 genes were examined by RT-qPCR methods. Results: A total of 130,068 differentially methylated sites (DMS, 58,474 hypermethylated, and 71,594 hypomethylated) between fibrotic liver tissues and control mice liver tissues were identified by the 850k BeadChips array. Consistency between pyrosequencing data and 850k BeadChips array data was observed (R=0.928; P<0.01). Apoptosis, positive regulation of transcription of Notch receptor target, and negative regulation of p38MAPK signal cascade activities were significantly enriched in the Gene Ontology (GO) analyses. Cholesterol metabolism, bile secretion, and more biosynthesis and metabolism pathways were enriched in KEGG pathway analyses. Ten key genes were identified by the Cytoscape plugin cytoHubba. Conclusion: 7850 genes were found to have methylation change in fibrotic liver tissues of mice, which facilitates future research for clinical application.

Fenbendazole Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice via Suppression of Fibroblast-to-Myofibroblast Differentiation.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal interstitial lung disease with unknown etiology. Despite substantial progress in understanding the pathogenesis of pulmonary fibrosis and drug development, there is still no cure for this devastating disease. Fenbendazole (FBZ) is a benzimidazole compound that is widely used as an anthelmintic agent and recent studies have expanded the scope of its pharmacological effects and application prospect. This study demonstrated that FBZ treatment blunted bleomycin-induced lung fibrosis in mice. In vitro studies showed that FBZ inhibited the proliferation and migration of human embryo lung fibroblasts. Further studies showed that FBZ significantly inhibited glucose consumption, moderated glycolytic metabolism in fibroblasts, thus activated adenosine monophosphate-activated protein kinase (AMPK), and reduced the activation of the mammalian target of rapamycin (mTOR) pathway, thereby inhibiting transforming growth factor-ß (TGF-ß1)-induced fibroblast-to-myofibroblast differentiation and collagen synthesis. In summary, our data suggested that FBZ has potential as a novel treatment for pulmonary fibrosis.

Inhibition of MAD2L1 Mediates Pulmonary Fibrosis through Impairment of Mitochondrial Function and Induction of Cell Senescence.

Idiopathic pulmonary fibrosis (IPF) is a chronic, irreversible, and progressive interstitial lung disease characterized by recurrent alveolar epithelial cell injury, fibroblast hyperproliferation, and cumulative deposition of extracellular matrix leading to alveolar destruction in the lungs. Mitotic arrest deficient 2 like 1 (MAD2L1) is a component of the mitotic spindle assembly checkpoint that prevents the onset of anaphase until all chromosomes are properly aligned at metaphase and is a potential therapeutic target in cancers. However, the role of MAD2L1 in pulmonary fibrosis has not been explored. We analyzed the expression of MAD2L1 in lung tissues from control subjects, IPF patients, and mice with bleomycin-induced fibrosis via IHC, qRT-PCR, and Western blot analysis. We examined the roles of MAD2L1 in ROS production, mitochondrial function, cell senescence, and the establishment of a profibrotic microenvironment. We found that MAD2L1 was highly upregulated in alveolar epithelial cells in fibrotic lung tissues from both patients with IPF and mice with bleomycin-induced fibrosis. Loss of MAD2L1 expression or activity led to decreases of cell viability and proliferation in A549 cells. Subsequent mechanistic investigation demonstrated that inhibition of MAD2L1 damaged mitochondria, which led to augmented ROS production and cellular senescence, and thus promoted the establishment of a profibrotic microenvironment. Taken together, these results reveal that alleviation of alveolar epithelial cell mitochondrial damage arising from augmentation of MAD2L1 may be a novel therapeutic strategy for mitigating pulmonary fibrosis.

Valley polarization transition driven by biaxial strain in Janus GdClF monolayer.

The valley degree of freedom of carriers in crystals is useful to process information and perform logic operations, and it is a key factor for valley application to realize valley polarization. Here, we propose a model that the valley polarization transition at different valley points (-K and K points) is produced by biaxial strain. Using first-principles calculations, we illustrate our idea with a concrete example of a Janus GdClF monolayer. The predicted GdClF monolayer is dynamically, mechanically and thermally stable, and is a ferromagnetic (FM) semiconductor with perpendicular magnetic anisotropy (PMA), valence band maximum (VBM) at valley points and a high Curie temperature (TC). Due to its intrinsic ferromagnetism and spin-orbit coupling (SOC), a spontaneous valley polarization will be induced, but the valley splitting is only -3.1 meV, which provides an opportunity to achieve valley polarization transition at different valley points by strain. In the considered strain range (a/a0: 0.94-1.06), the strained GdClF monolayer always has an energy bandgap, strong FM coupling and PMA. The compressive strain is in favour of -K valley polarization, while the tensile strain is favorable for K valley polarization. The corresponding valley splittings at 0.96 and 1.04 strains are -44.5 meV and 29.4 meV, respectively, which are higher than the thermal energy at room temperature (25 meV). Due to its special Janus structure, both in-plane and out-of-plane piezoelectric polarizations can be observed. It is found that the direction of in-plane piezoelectric polarization can be overturned by strain, and the d11 values at 0.96 and 1.04 strains are -1.37 pm V-1 and 2.05 pm V-1, respectively. Our work paves the way to design ferrovalley materials for application in multifunctional valleytronic and piezoelectric devices by strain.

Rifaximin Improves Visceral Hyperalgesia via TRPV1 by Modulating Intestinal Flora in the Water Avoidance Stressed Rat.

BACKGROUND: Rifaximin is effective in relieving pain symptoms with IBS patients, although the mechanisms were not clear. The aims of the research were to investigate whether the visceral hyperalgesia was alleviated by rifaximin via TRPV1 channel in rats. METHODS: Rats were subjected to water avoidance stress (WAS) and were pretreated with rifaximin by oral gavage. The visceromotor response to colorectal distension was measured. The changes of TRPV1 in peripheral and central neurons of rats were detected by immunofluorescence, western blot method, and RT-PCR. Bacterial 16S ribosomal DNA in ileal contents was assessed using the Illumina MiSeq platform. The effect of intestinal flora on TRPV1 channel was observed by fecal microbiota transplantation (FMT) methods. RESULTS: Rifaximin could relieve the visceral hyperalgesia and reduce the TRPV1 expression of neurons and ileum mucosa in rats induced by WAS. The reduced relative abundance of intestinal flora induced by WAS could be partly prevented by rifaximin. The electromyographical activities and immunoreactivity of TRPV1 in rats could be changed after FMT. CONCLUSIONS: Rifaximin could improve visceral hyperalgesia via TRPV1 channels of peripheral and central neurons by modulating intestinal flora in rats.

Predicted Janus SnSSe monolayer: a comprehensive first-principles study.

The Janus structure, by combining properties of different transition metal dichalcogenide (TMD) monolayers in a single polar material, has attracted increasing research interest because of its particular structure and potential application in electronics, optoelectronics and piezoelectronics. In this work, Janus SnSSe monolayer is predicted by means of first-principles calculations, and it exhibits dynamic and mechanical stability. By using the generalized gradient approximation (GGA) and spin-orbit coupling (SOC), the Janus SnSSe monolayer is found to be an indirect band-gap semiconductor, whose gap can easily be tuned by strain. High carrier mobilities are obtained for SnSSe monolayer, and the hole mobility is higher than the electron mobility. For SnSSe monolayer, a uniaxial strain in the basal plane can induce both strong in-plane and much weaker out-of-plane piezoelectric polarizations, which reveals the potential as a piezoelectric two-dimensional (2D) material. High absorption coefficients in the visible light region are observed, suggesting a potential photocatalytic application. Calculated results show that SnSSe monolayer has a very high power factor, making it a promising candidate for thermoelectric applications. Our works reveal that the Janus SnSSe structure can be fabricated with unique electronic, optical, piezoelectric and transport properties, and can motivate related experimental works.

Born effective charge removed anomalous temperature dependence of lattice thermal conductivity in monolayer GeC.

Due to potential applications in nano- and opto-electronics, two-dimensional (2D) materials have attracted tremendous interest. Their thermal transport properties are closely related to the performance of 2D materials-based devices. Here, the phonon transports of monolayer GeC with a perfect planar hexagonal honeycomb structure are investigated by solving the linearized phonon Boltzmann equation within the single-mode relaxation time approximation (RTA). Without inclusion of Born effective charges (Z *) and dielectric constants ([Formula: see text]), the lattice thermal conductivity ([Formula: see text]) decreases almost linearly above 350 K, deviating from the usual [Formula: see text] law. The underlying mechanism is because the contribution to [Formula: see text] from high-frequency optical phonon modes increases with increasing temperature, and the contribution exceeds one from acoustic branches at high temperature. These can be understood by huge phonon band gap caused by large difference in atom mass between Ge and C atoms, which produces important effects on scattering process involving high-frequency optical phonon. When considering Z * and [Formula: see text], the phonon group velocities and phonon lifetimes of high-frequency optical phonon modes are obviously reduced with respect to ones without Z * and [Formula: see text]. The reduced group velocities and phonon lifetimes give rise to small contribution to [Formula: see text] from high-frequency optical phonon modes, which produces the the traditional [Formula: see text] relation in monolayer GeC. Our works highlight the importance of Z * and [Formula: see text] to investigate phonon transports of monolayer GeC, and motivate further theoretical or experimental efforts to investigate thermal transports of other 2D materials.

[Expression of interferon-induced protein with tetratricopetide repeats 1 and liver cell apoptosis in mice with severe burns].

OBJECTIVE: To explore the relationship between the expression of interferon-induced protein with tetratricopetide repeats 1 (IFIT1) and liver cell apoptosis in the acute stress period after severe burns.
 METHODS: A total of 25 C57/129 adult mice were randomly divided into the normal control group (0 h) and the groups at 1, 6, 12 or 24 after severe burns (n=5 per group). A model with third degree (20% of the total body surface area) burn injury was established and then liver tissues were taken. IFIT1 expression was examined by Western blot. The expression of caspase-3 and -8 was measured by immunohistochemistry. Liver cell apoptosis was detected by terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL).
 RESULTS: After burns, IFIT1 expression was increased at 1 h, which reached the highest level at 6 h followed by a decrease at 12 h, which reached minimum level at 24 h. The differences between groups were significant (P<0.01). The caspase-3 and -8 levels significantly increased after burns in a time-dependent manner (P<0.01). Although at 0 h and 1 h there was no significant increase in liver cell apoptosis, the increase reached significance from 6 h to 24 h (P<0.01).
 CONCLUSION: The increase in IFIT1 expression after severe burns promotes liver cell apoptosis.

[Effect of ropivacaine on proliferation and migration of rat bone marrow mesenchymal stem cells].

OBJECTIVE: To observe the influence of ropivacaine on the proliferation and migration of rat bone marrow mesenchymal stem cells (BMSCs) and provide basis for the clinical application of BMSCs. METHODS: Rat BMSCs were isolated and cultured by adherence method. Surface markers of BMSCs were examined by flow cytometry. Multipotent differentiation of BMSCs was detected by induced adipogenesis, osteogenesis and muscular differentiation. Proliferation of BMSCs was examined by CCK-8 and Brdu incorporation after ropivacaine treatment at different concentrations. Migration of BMSCs was tested by cell scratch assay and Millicell experiment. RESULTS: Cultured cells had representative appearance and surface markers of BMSC, and they had potential multiple differentiation. Ropivacaine treatment at 50 and 100 µmol/L significantly reduced the proliferation rate of BMSCs and Brdu incorporation rate. There was significant difference compared with the control group (P<0.05). Cellular scratch assay and migration experiment indicated that ropivacaine significantly reduced the migration of BMSCs. There was significant difference compared with the control group (P<0.05). All these mentioned effects of ropivacaine on BMSCs were dose-dependent. There was significant difference between groups (P<0.05). CONCLUSION: Ropivacaine can significantly reduce the proliferation and migration of rat BMSCs, suggesting that the influence of local anesthetics on BMSCs has to be taken into account when BMSCs are used in clinical practice.