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Low-dimensional ferroelectricity and polar materials have attracted considerable attentions for their fascinating physics and potential applications. Based on first-principles calculations, here we investigate the stacking modes and polar properties of a typical series of quasi-one-dimensional ferroelectrics: double-chain oxyhalides NbO$X_3$ ($X$=Cl, Br, I). The geometry of their double-chains allows both the interchain/intrachain permutation. Thus, different stacking modes of double-chains lead to a variety of ferroelectric and antiferroelectric phases in both the tetragonal and monoclinic crystals. The proximate energies of these phases may lead to multiphase coexistence in real materials, as well as the hydrostatic pressure driving structural phase transition. Their spontaneous polarizations and piezoelectricity of the ferroelectric phases are prominent, comparable to commercially used ferroelectric BaTiO$_3$ and piezoelectric ZnO, respectively. Our work demonstrates that the van der Waals NbO$X_3$ are promising materials for exploring quasi-one-dimensional ferroelectricity and antiferroelectricity., Comment: 7 pages, 5 figures

Thyroid cancer is a frequently happened malignancy in human endocrine system. Papillary thyroid cancer (PTC) presents 70–80% of all thyroid cancer cases. Herein, we probed the possible oncogenic fu...

This study uses the network topology of variance decompositions to investigate the connectedness of four assets (stocks, bonds, foreign exchange and commodities) across five countries (US, EU, UK, Japan and China). We find that connectedness to and from the Chinese asset markets increased significantly from 2013 to 2018, which reveals that Chinese assets have gradually become integrated into the global economy. We also investigate the volatility connectedness in economically fragile periods and find that the Chinese market acted as a transmitter of volatility in the 2015 Chinese stock crash. This finding is potentially essential to modern risk measurement and management.

Long noncoding RNAs (lncRNAs) play an essential role in the progression of papillary thyroid cancer (PTC). However, the expression and function of lncRNA cancer susceptibility candidate 7 (CASC7) in PTC remain unknown. The purpose of this study was to investigate the role and molecular mechanism of CASC7 in regulating PTC cell behavior. The expression of CASC7, miR-34a-5p, and tumor protein P73 (TP73) was determined by qRT-PCR and western blot. Cell proliferation was examined by MTT assay. Cell apoptosis was assessed by flow cytometry following Annexin V and PI staining. Cell migration was determined by Transwell migration assay. The interaction between miR-34a-5p and CASC7 or TP73 was examined by luciferase reporter assay. CASC7 and TP73 expression were significantly lower, whereas miR-34a-5p expression was higher in PTC tissues than the adjacent normal tissues. Furthermore, CASC7 overexpression inhibited cell proliferation and migration, whereas facilitated cell apoptosis in human PTC cell lines (K1 and TPC-1). Mechanistically, CASC7 acted as a sponge of miR-34a-5p to upregulate TP73 expression. Moreover, miR-34a-5p mimic transfection could abate the CASC7-regulated PTC cell proliferation, migration, and apoptosis. Collectively, CASC7 inhibited the proliferation and migration of PTC cells by sponging miR-34a-5p to upregulate TP73 expression.

Two-dimensional topological materials attracted intense interest in condensed matter physics due to their topologically protected edge states and potential applications in electronic devices. Here, based on first-principles calculations, we found that a two-dimensional CX3 (X = Sb, Bi) monolayer is a quantum spin Hall insulator with a large band gap. With the strong spin-orbit coupling effect, CX3 exhibits noticeable bulk band gaps up to 470 meV, sufficiently large for realizing the quantum spin Hall effect at room temperature. The topological characteristic is confirmed by the Z2 invariant since the system preserves time-reversal symmetry. Particularly, the CSb3 monolayer displays unique topologically entangled Rashba-splitting edge states, resembling nearly free-electron quadratic dispersion. Such topologically entangled Rashba-like edge states derive from the spin-orbit coupling effect and inversion symmetry breaking on the edges. Moreover, we demonstrate that the topological properties are perfectly preserved in the CX3 monolayer even with a h-BN substrate. The nontrivial quantum spin Hall state in the CX3 monolayer will provide possibilities for studying a novel phenomenon of edge states and potential applications in low-dissipation electronic devices.

Electrocatalytic CO2 reduction (ECO2RR) is a very promising new energy technology for carbon capture, utilization and storage. The chemical inertness of CO2 makes its conversion needs to be driven by efficient catalysts. Polyoxometalate (POM) inhibits hydrogen evolution side reaction (HER) for ECO2RR via proton coupling in their reversible, stepwise multi-electron transfer reactions. In this work, indium and prepared (n-Bu4N)3SVW11O40 (SVW11) work as synergetic catalysis firstly for ECO2RR to acetic acid and ethanol with 67.4% and 19.4%, respectively. The provided electron transferred to vanadium center in SVW11 and In3+ leading to the activity of In recovered and HSVIVW11O403− formed, where the proton-coupled electron transfer step of VIV/V in SVW11 electrolyte promoted the process of ECO2RR. The isomerized POM effectively reducing the reaction overpotential and increasing the products selectivity also.

This paper investigates the impact of global economic policy uncertainty (GEPU) on the volatility of the Chinese stock market and whether GEPU has predictive power for the volatility of the Chinese stock market. We apply the generalized autoregressive conditional heteroscedastic mixed data sampling (GARCH–MIDAS) model to evaluate the impact of the monthly GEPU index on the daily Shanghai Composite index. Our empirical results show that GEPU has a positive and significant influence on the volatility of the Chinese stock market, which reflects that Chinese stock market has been gradually integrated into the global economy. In addition, the forecasts generated by the GARCH–MIDAS model with GEPU and RV (Realized Volatility) produce substantially smaller errors than the GARCH (1,1) model and the GARCH–MIDAS model with RV (measured by RMSE, RMAE, RMSD, RMAD loss functions and DM test), which confirms the important role of GEPU for predicting the volatility of the Chinese stock market. Overall, our findings imply that GEPU is an additional driving factor of long-term volatility in the Chinese stock market.

Thyroid cancer is a frequently happened malignancy in human endocrine system. Papillary thyroid cancer (PTC) presents 70-80% of all thyroid cancer cases. Herein, we probed the possible oncogenic function of long non-coding RNA (lncRNA) highly up-regulated in liver cancer (HULC) in PTC. First, the HULC and microRNA-106a (miR-106a) expressions in PTC tissues and cells were tested. Plasmids or miRNAs transfections were done for altering HULC and miR-106a expressions. Then, cells viability and apoptosis, along with cell proliferative, migratory and invasive abilities, were tested, respectively. The PI3K/AKT and Wnt/β-catenin pathways activities were measured. Finally, the animal model of PTC was constructed and the tumour volumes and weights were gauged. We discovered that HULC and miR-106a had relative high expression levels in PTC tissues and cells. HULC overexpression enhanced TPC-1 cells viability and cell proliferative, migratory and invasive abilities. Silencing HULC induced TPC-1 cell apoptosis. miR-106a engaged in the oncogenic impacts of HULC. Moreover, HULC overexpression boosted PI3K/AKT and Wnt/β-catenin pathways activities

MicroRNAs (miRNAs) are small non-coding RNAs that, by targeting certain messenger RNAs (mRNAs) for translational repression or cleavage, can regulate the expression of these genes. In addition, miRNAs may also function as oncogenes and tumor-suppressor genes, as the abnormal expression of miRNAs is associated with various human tumors. However, the effects of the expression of miR-124 in breast cancer remain unclear. The present study was conducted to study the expression of miR-124 in breast cancer, paying particular attention to miR-124's relation to the proliferation, invasion, and apoptosis in breast cancer cell MCF-7 and MDA-MB-231. Real-time quantitative RT-PCR (qRT-PCR) was performed to identify miR-124 that was down-regulated in breast cancer tissues. We also showed E26 transformation specific-1 (Ets-1) and miR-124 expression levels in breast cancer tissues that were associated with lymph node metastases. With transfected synthetic miR-124 agomir into MCF-7 and MDA-MB-231, a significant reduction (P < 0.05) in MCF-7 and MDA-MB-231 cell proliferation and colony forming potential was observed after treatment with miR-124. Apoptosis and migration rates were found to be significantly higher in two breast-derived cell lines transfected with a miR-124 agomir (P < 0.05). Luciferase reporter assay and Western blot were used to verify Ets-1 as a potential major target gene of miR-124, and the result showed that miR-124 can bind to putative binding sites within the Ets-1 mRNA 3' untranslated region (UTR) to reduce its expression. Based on these findings, we propose that miR-124 and Ets-1 may serve as a therapeutic agent in breast cancer.