Search

Sanggenon C is a flavonoid extracted from the root bark of white mulberry, which is a traditional Chinese medicine with anti-inflammatory, antioxidative, and antitumor pharmacological effects. In this study, sanggenon C was found to inhibit human gastric cancer (GC) cell proliferation and colony formation, induce GC cell cycle arrest in the G0-G1 phase, and promote GC cell apoptosis. Moreover, sanggenon C was found to decrease the level of mitochondrial membrane potential in GC cells and inhibit mitochondrial fission. Mechanistically, RNA sequencing, bioinformatics analysis, and a series of functional analyses confirmed that sanggenon C inhibited mitochondrial fission to induce apoptosis by blocking the extracellular regulated protein kinases (ERK) signaling pathway, and constitutive activation of ERK significantly abrogated these effects. Finally, sanggenon C was found to suppress the growth of tumor xenografts in nude mice without obvious side effects to the vital organs of animals. This study reveals that sanggenon C could be a novel therapeutic strategy for GC treatment.

Recently, the AlB2-type compounds such as AlB2 and MgB2 have attracted immense interest due to the Dirac Nodal Line (DNL). This unique electronic structure is very important for the design and disc...

To illustrate the effects of long-term straw returning on the fungal community, soil enzyme activity, and crop yield in a fluvo-aquic soil area typical of the Huang-Huai-Hai Plain, a 10-year field experiment (established in 2010) located in Dezhou City, Shandong province, was performed, including three fertilization regimes (NF, no fertilization control; NPK, fertilization with chemical N, P, and K fertilizers; NPKS, straw returning combined with chemical N, P, and K fertilizers). This study aimed to explore the regulation mechanisms of fungal communities on soil fertility, enzyme activities, and crop yield by employing co-occurrence network and structural equation model analyses. Our results showed that long-term straw returning significantly improved soil nutrients, enzyme activity, and wheat yield. Compared with the NPK and NF treatments, soil organic matter (SOM) increased by 9.20% and 34.75%, alkali-hydrolyzed nitrogen (AN) increased by 12.03% and 39.17%, dehydrogenase (DHA) increased by 37.21% and 50.91%

To investigate knowledge transfer efficiency, this study applies a metafrontier epsilon‐based measure (EBM) model to survey data for 102 Chinese and African multinational enterprises (C–A MNEs). The results are as follows. (1) Only 14 of the 102 C–A MNEs have an efficiency score of 1. (2) The scores for different indicators of the same enterprise vary significantly. (3) Technical support input is inefficient, with all major industries showing obvious disadvantages. (4) Team performance efficiency scores significantly lag behind the other output variables' efficiency scores, presenting significant room for improvement. (5) There are differences in the efficiency of knowledge transfer among different industries.

Recently, the AlB2-type compounds (such as AlB2 and MgB2) which exhibit Dirac Nodal Line (DNLs) semimetal on their electronic band structure and Phononic Weyl Nodal Straight Lines (PTWNLs) on their...

To investigate the therapeutic effect of Er-Xian decoction on the autoimmune premature ovarian failure (POF) in mice, and its regulatory mechanisms.Female BALB mice were treated with a single intraperitoneal injection of zona pellucida 3 (ZP3). One week later, mice received low (5 g/kg), moderate (10 g/kg) and high (20g/kg) doses of EXD by gastrogavage once daily for 90 d. Premarin (0.03 mg/kg) served as the positive control group. Serum levels of estradiol (E2), follicle stimulating hormone (FSH) and luteinizing hormone (LH) were measured by enzyme-linked immunosorbent assay, lymphocyte subtypes were analyzed, and follicular structure differences were observed by hematoxylin and eosin staining. The main mechanisms of POF was investigated by immunohistochemical analysis.Serum E2 levels in POF model mice were decreased, whereas FSH and LH levels were dramatically increased. Serum levels of LH and FSH were reduced in POF model mice treated with EXD (moderate and high doses) and premarin, while serum level of E2 were increased after POF model mice had been treated with EXD and premarin. The CD3+ T, CD4+ T, CD4+ T/CD8+ T ratio of mice in the positive control group and high and medium dose groups of EXD increased (P0.05), and the number of CD8 + T cells decreased significantly (P0.05) when compared with the model group. Bone morphogenetic protein 15 (BMP15) and Akt were repressed in autoimmune POF model mice, whereas high expression was observed in control mice and those treated with EXD (moderate and high doses) and premarin.EXD is effective in treating ZP3-induced POF in mice and increased expression of BMP-15, and Akt is represented in the mechanism accounting for this therapeutic effect.

The water oxidation reaction (WOR) is a bottleneck in water splitting. Though many catalysts have been developed for this reaction, cost-effective, robust and efficient electrocatalysts based on non-precious metals are still highly desired. Herein reported are the synthesis, characterization and electrocatalytic properties of a dicopper(II) complex of the tetrapyridyl ligand N,N,N′,N′-tetrakis(2-pyridylmethyl)-1,4-butanediamine (tpbn) and 2,2′-bipyridine (bpy), [Cu2(tpbn)(bpy)2](ClO4)4·2CH3COCH3 (1). The X-ray single crystallography analysis revealed that the tpbn ligand bridges two copper(II) centers located in a square pyramidal environment composed of one bpy ligand as well as two pyridyl and one amino groups of a tpbn. Complex 1 was a molecular electrocatalyst for WOR in 0.1 M NaOAc–NaOH solutions of pH 11.0–14.0. It was demonstrated that the incorporation of the ancillary ligand bpy into the tpbn-bridged dicopper(II) complex is crucial for the stabilization of the catalytic system and the enhancement of the activity. This work provided an alternative to achieve robust homogeneous catalytic systems with better performance.

We investigate systematically the plasmon excitations for three silicon (Si2, Si6, and Si10) nanostructures (NS) based on time-dependent density functional theory and find that there are two obviou...

The application of natural eutectic solvent (NDDES) in organic synthesis has received more and more attention. In this work, a green protocol for one-pot synthesis of spiro[indoline-3,4′-pyrazolo[3,4-b]pyridines] via three-component reactions of 1H-pyrazol-5-amin, isatin and enolizable C H activated compound is achieved by the combination of microwave irradiation with choline chloride and lactic acid based NDDES. This novel method is clean, cheap, simple, high yield, chromatography-free and scalable. The use of choline chloride and lactic acid as a biodegradable, recycled and reusable media meets most of the criteria to be considered as a sustainable and environmentally benign process.

The trachea of insects is a tubular epithelia tissue that transports oxygen and other gases. It serves as a useful model for the studying of the cellular and molecular events involved in epithelial tube formation. Almost all of the extracellular matrix can be degraded by Matrix metalloproteinases (MMPs), which is closely related to the processes of development and regeneration. The regulation of trachea by MMPs is roughly known in previous studies, but the detailed regulation mechanism and involved gene function are not fully explored. In this article, we found MMP1 expressed highly during tracheal remodeling, and knocked out it makes the tracheal branch number reduced in Bombyx mori. In trachea of transgenic BmMMP1-KO silkworm, the space expanding of taenidium and epidermal cells and the structure of apical membrane were abnormal. To explore the underlying mechanism, we detected that DE-cadherin and Integrin β1 were accumulated in trachea of transgenic BmMMP1-KO silkworm by immunohistochemistry. Moreover, 5-Bromo-2′-Deoxyuridine (BrdU) labeling showed that knockout of BmMMP1 in silkworm inhibited tracheal cell proliferation, and BmMMP1 also regulated the proliferation and migration of BmNS cells. All of the results demonstrated that BmMMP1 regulates the development of the tracheal tissue by expanding the space of tracheal cuticles and increases the number of tracheal branches by degrading DE-cadherin and Integrin β1.

The trachea of insects is a tubular epithelia tissue that transports oxygen and other gases. It serves as a useful model for the studying of the cellular and molecular events involved in epithelial tube formation. Almost all of the extracellular matrix can be degraded by Matrix metalloproteinases (MMPs), which is closely related to the processes of development and regeneration. The regulation of trachea by MMPs is roughly known in previous studies, but the detailed regulation mechanism and involved gene function are not fully explored. In this article, we found MMP1 expressed highly during tracheal remodeling, and knocked out it makes the tracheal branch number reduced in Bombyx mori. In trachea of transgenic BmMMP1-KO silkworm, the space expanding of taenidium and epidermal cells and the structure of apical membrane were abnormal. To explore the underlying mechanism, we detected that DE-cadherin and Integrin β1 were accumulated in trachea of transgenic BmMMP1-KO silkworm by immunohistochemistry. Moreover, 5-Bromo-2′-Deoxyuridine (BrdU) labeling showed that knockout of BmMMP1 in silkworm inhibited tracheal cell proliferation, and BmMMP1 also regulated the proliferation and migration of BmNS cells. All of the results demonstrated that BmMMP1 regulates the development of the tracheal tissue by expanding the space of tracheal cuticles and increases the number of tracheal branches by degrading DE-cadherin and Integrin β1.

Although the progression of invasive aspergillosis (IA) shares some risk factors in the development of active pulmonary tuberculosis (PTB), however, the prevalence of IA in suspected PTB remains unclear. During a period of 1 year (from January 2016 to December 2016), consecutive patients with suspected PTB were included in a referral TB hospital. Data, including demographic information and underlying diseases, were collected from medical records. PTB were all confirmed by mycobacterial culture (Lowenstein–Jensen medium). IA were diagnosed as proven or probable according to the criteria of the 2008 EORTC/MSG definitions. A descriptive analysis was performed to estimate the corresponding prevalence. During the study year, 1507 patients have a positive mycobacterial culture, with a mean age of 45.6 (s.d.19.9) years old and a female:male ratio of 1:4. Among the 82 patients with non-tuberculous mycobacterial diseases, two patients (2.44%, 95% CI 0.67–8.46%) were diagnosed as IA (one proven and one probable); two probable IA patients (0.15%, 95% CI 0.04–0.55%) were diagnosed in PTB patients (n= 1315), and all were retreatment cases. In addition, all four IA patients (100%) exhibited cavities in both lobes on radiograph. In China, the prevalence of IA is low in active PTB patients. However, when high-risk factors for IA are encountered in PTB patients, further investigations are required and empirically treatment for IA might be warranted.

Silicon carbide (SiC) chains and silicon carbide nanotubes (SiCNTs), as promising one-dimensional nanostructures, have potential applications in more controllable nanoelectronic devices. In this paper, we design a completely new hybrid structure with encapsulation of a linear SiC chain inside a SiCNT, using first-principles calculation and the non-equilibrium Green's function formalism to systematically investigate the structural stability and electronic properties, particularly the quantum transport properties. It is found that, due to the nanotube-chain interaction, the stability of this structure is mainly provided by the charge transfer from the hosting tube to the guest chain. Furthermore, the transport properties of the hybrid structure confirm that encapsulation of a SiC chain within a SiCNT can significantly enhance the electronic transport of the component system in a wide range of high voltage. The distance and the unique coupling configuration between the encapsulated system and the electrodes are demonstrated to be other important factors that affect the transport behaviours. We hope that our study of encapsulation may offer a significant starting point for the design of new materials related to low-dimensional SiC nanostructures and possibly open a novel path towards stability and conductivity enhancement.

Cyclin-dependent kinase inhibitors (CKIs) are negative regulators of the cell cycle. They can bind to cyclin-dependent kinase (CDK)-cyclin complexes and inhibit CDK activities. We identified a single homologous gene of the CDK interacting protein/kinase inhibitory protein (Cip/Kip) family, BmCKI, in the silkworm, Bombyx mori. The gene transcribes two splice variants: a 654-bp-long BmCKI-L (the longer splice variant) encoding a protein with 217 amino acids and a 579-bp-long BmCKI-S (the shorter splice variant) encoding a protein with 192 amino acids. BmCKI-L and BmCKI-S contain the Cip/Kip family conserved cyclin-binding domain and the CDK-binding domain. They are localized in the nucleus and have an unconventional bipartite nuclear localization signal at amino acid residues 181-210. Overexpression of BmCKI-L or BmCKI-S affected cell cycle progression; the cell cycle was arrested in the first gap phase of cell cycle (G1). RNA interference of BmCKI-L or BmCKI-S led to cells accumulating in the second gap phase and the mitotic phase of cell cycle (G2/M). Both BmCKI-L and BmCKI-S are involved in cell cycle regulation and probably have similar effects. The transgenic silkworm with BmCKI-L overexpression (BmCKI-L-OE), exhibited embryonic lethal, larva developmental retardation and lethal phenotypes. These results suggest that BmCKI-L might regulate the growth and development of silkworm. These findings clarify the function of CKIs and increase our understanding of cell cycle regulation in the silkworm.

Endoreplication, known as endocycles or endoreduplication, is a cell cycle variant in which the genomic DNA is re-replicated without mitosis leading to polyploidy. Endoreplication is essential for the development and functioning of the different organs in animals and plants. Deletion of Geminin, a DNA replication licensing inhibitor, causes DNA re-replication or damage. However, the role of Geminin in endoreplication is still unclear. Here, we studied the role of Geminin in the endoreplication of the silk gland cells of silkworms by constructing two transgenic silkworm strains, including BmGeminin1-overexpression and BmGeminin1-RNA interference. Interference of BmGeminin1 led to body weight gain, increased silk gland volume, increased DNA content, and enhanced DNA re-replication activity relative to wild-type Dazao. Meanwhile, overexpression of BmGeminin1 showed an opposite phenotype compared to the BmGem1-RNAi strain. Furthermore, RNA-sequencing of the transgenic strains was carried out to explore how BmGeminin1 regulates DNA re-replication. Our data demonstrated a vital role of Geminin in the regulation of endoreplication in the silk gland of silkworms.

The ground state properties of the rotating Bose–Einstein condensates (BECs) with SU(3) spin–orbit coupling (SOC) in a two-dimensional harmonic trap are studied. The results show that the ferromagnetic and antiferromagnetic systems present three half-skyrmion chains at an angle of 120° to each other along the coupling directions. With the enhancement of isotropic SU(3) SOC strength, the position of the three chains remains unchanged, in which the number of half-skyrmions increases gradually. With the increase of rotation frequency and atomic density–density interaction, the number of half-skyrmions on the three chains and in the regions between two chains increases gradually. The relationships of the total number of half-skyrmions on the three chains with the increase of SU(3) SOC strength, rotation frequency and atomic density–density interaction are also given. In addition, changing the anisotropic SU(3) SOC strength can regulate the number and morphology of the half-skyrmion chains.

Motivated by the recent experimental exfoliation of tellurium thin film, and the amazing physical and chemical properties of various theoretically tellurene allotropes, we design a novel and stable pentagonal structure of tellurene (SP-type Te), and make a detailed comparison with other possible Te allotropes, related to their mechanical, electronic and thermoelectric properties. SP-type Te shows the higher expandability than other Te allotropes, due to its lower layer modulus and Young’s modulus. More interestingly its Poisson’s ratio along x (y) direction is unusually negative ( ~ −0.01) which can be further decreased by applying coaxial strain. Three-layers SP-type Te can turn into a topological insulator (TI) with a nontrivial band gap ~ 0.03 eV when uniaxial compressional strain σ x = −7 % . Moreover the higher the number of layers in SP-type Te, the lower σ x inducing its topological transition requires. At room temperature, lattice thermal conductivity k L of SP-type Te is the lowest in all Te allotropes, and meanwhile its peak ZT for n-type doping even can reach up to 2.84. Thus if SP-type Te can be synthesized in future, these extraordinary properties would promote it with great potential in designing low-dimensional mechanical, spintronic and thermoelectric devices.

The mechanical, electronic and thermodynamic properties of MTe 2 (M = Ni, Pd and Pt) under high pressure were investigated via the first-principles calculations. According to our calculations of these trigonal crystals (space group of P3M1 , No: 164), we found that all of them are fulfilled by the mechanical stability criteria under 31 GPa (for NiTe 2 ), 37 GPa (for PdTe 2 ) and 73 GPa (for PtTe 2 ). The study on their structures revealed the elastic anisotropy of these isostructural compounds. Electronic structure calculations show that MTe 2 are semi-metal. On the basis of the quasi-harmonic Debye model, we also researches their thermodynamic properties.

Objective Currently, the prevalence of multidrug-resistant tuberculosis (MDR-TB) in childhood tuberculosis (TB) in Shandong, China remains unclear. We retrospectively conducted laboratory-based surveillance in a high TB burden district, to analyze the local prevalence of MDR-TB in childhood TB. Methods We collected data, including microbiological results and demographic and disease information, using a questionnaire and medical records. We used the chi-squared test to compare the prevalence of MDR-TB in childhood TB between two periods: 2008 to 2013 and 2014 to 2018. Results In Shandong, the prevalence of MDR-TB in childhood TB was low, at 5.6%. Between 2008-2013 and 2014-2018 among children with TB, the prevalence of MDR-TB remained unchanged, the proportion with pulmonary TB decreased from 78.3% to 64.9%, and the proportion with a TB contact history decreased from 20.5% to 9.9%. Conclusions The prevalence of MDR-TB among childhood TB in Shandong, China was low and has remained stable over the past years. However, non-tuberculous mycobacterial diseases may be a new challenge in the management of suspected childhood TB.

Based on first-principles calculations and theoretical analysis, we investigated various properties of pristine monolayer M

The layer-by-layer assembly of polyethyleneimine and carbon nanotubes is carried out through the electrostatic interactions on colloidal polystyrene templates. The successful spherical growth of polyethyleneimine/carbon nanotube multilayers could be investigated by SEM. The subsequent in situ preparation and deposition of gold nanoparticles on the core–shell composites could yield novel microsphere complexes, which are characterized by SEM, TEM, EDX and XRD. The functional hierarchical microspheres with gold nanoparticles exhibit good catalytic activity in the reaction of reducing 4-nitrophenol to 4-aminophenol.

For the research of Transition Metal Dichalcogenides (TMDCs), the predecessors have already involved a lot. However, the research of the two-dimensional square-octagon MoS2 (so-MoS2) with elastic and thermal properties are not enough. Here, we have investigated the electronic, phonon, elastic and thermal properties of the primitive monolayer so-MoS2 by first-principles calculations and theoretical analysis. Firstly, The Dirac point exists on its band structure and mainly contributed by d orbits of Mo atoms, it will open the energy gap and enter the insulating phase when the spin–orbit coupling is added. Secondly, the phonon spectrum indicates that so-MoS2 is dynamically stable. The Raman, infrared active modes were also studied. Thirdly, we investigated the elastic constants of monolayer so-MoS2 by the nonlinear least-squares fitted the relation between energy density and strain. We find monolayer so-MoS2 has better flexibility than other two-dimensional materials, such as, monolayer MoS2. Moreover, we investigated the elastic properties of twisted and strained so-MoS2 and it is found that twisting and straining have little effect on the elasticity of monolayer so-MoS2 and they are all elastic isotropic. Finally, the thermodynamic properties of the Gruneisen parameter, thermal expansion coefficient, CV, entropy and lattice thermal conductivity of monolayer so-MoS2 were also studied. We used two methods of grun and phonopy-qha to analyze Gruneisen parameter and Thermal expansion coefficient, and find phonopy-qha method is better and more common. The study from hexagonal honeycomb lattice monolayer MoS2 to square lattice monolayer so-MoS2, which broadens the promising topological material systems.

Simple Summary Ecdysteroid titer determines the state of the cell cycle in silkworm (Bombyx mori) metamorphosis. However, the mechanism of this process is unclear. In this study, we reported that 20-Hydroxyecdysone (20E) can promote BmFoxO (Bombyx mori Forkhead box protein O) gene expression and induce BmFoxO nuclear translocation in BmN-SWU1 cells. Overexpression of the BmFoxO gene affects cell cycle progression, which results in cell cycle arrest in the G0/G1 phase as well as inhibition of DNA replication. Further investigations showed that the effect of 20E was attenuated after BmFoxO gene knockdown. The findings of this study confirmed that BmFoxO is a key mediator in the cell cycle regulation pathway induced by 20E. This suggests a novel pathway for ecdysteroid-induced cell cycle regulation in the process of silkworm metamorphosis, and it is likely to be conserved between Lepidoptera insects. Abstract Ecdysteroid titer determines the state of the cell cycle in silkworm (Bombyx mori) metamorphosis. However, the mechanism of this process is unclear. In this study, we demonstrated that the BmFoxO gene participates in the regulation of the cell cycle induced by 20-Hydroxyecdysone (20E) in BmN-SWU1 cells. The 20E blocks the cell cycle in the G2/M phase through the ecdysone receptor (EcR) and inhibits DNA replication. The 20E can promote BmFoxO gene expression. Immunofluorescence and Western blot results indicated that 20E can induce BmFoxO nuclear translocation in BmN-SWU1 cells. Overexpression of the BmFoxO gene affects cell cycle progression, which results in cell cycle arrest in the G0/G1 phase as well as inhibition of DNA replication. Knockdown of the BmFoxO gene led to cell accumulation at the G2/M phase. The effect of 20E was attenuated after BmFoxO gene knockdown. These findings increase our understanding of the function of 20E in the regulation of the cell cycle in B. mori.

Motivated by interesting physical and chemical properties created by doping and topological quantum state, we perform the density functional theory and the Boltzmann transport equation to systematically investigate the geometric structures, stabilities, electronic structures, thermal conductivities and thermoelectric properties for Sb and its oxidations (Sb2O and SbO). The predicted lattice thermal conductivity (k L ) of Sb is 11.6 nW K-1 at 300 K, but it would fall drastically when introducing O atoms. This is mainly attributed to the strong anharmonic interactions by adding O atoms, and few contributions are from the decreasing phonon group velocities caused by the compressed phonon spectrum. SbO has been proven as a topological insulator with a relatively large topological band gap (E g ) ∼ 0.156 eV, and meanwhile its carrier mobilities (345.78 cm2/Vs for electrons) and scattering time (44.27 × 10-14 s for electrons) are also rather high among all 2D materials, exhibiting the excellent thermoelectric performance. The calculated maximum thermoelectric figure of merit ([Formula: see text]) of the three Sb films for optimum n-type doping are close to each other at 300 K, but with an increasing temperature, the [Formula: see text] of Sb for optimum n-type doping climbs quickly and can reach up to 0.73 at 700 K, which is far higher than others. More interestingly, the [Formula: see text] of SbO can be increased sharply at 300 K after considering spin-orbit coupling (SOC): 0.50 for optimum p-type doping and 0.41 for optimum n-type doping. However, only the tiny changes in the [Formula: see text] of Sb can be found before and after considering SOC. Our research reveals how the doping and the topological quantum state affect thermoelectric performances, providing reference to design and search high [Formula: see text] thermoelectric materials in future.

The wireless sensor network (WSN) has limited bandwidth, low power consumption, and may have redundantly collected data. The effective compression of data to reduce the energy consumption in transmission is of great importance. To this end, we proposed a new data-compression algorithm for WSN. The key idea of the algorithm is based on an adaptive threshold and piecewise linear fitting. The adaptive threshold is automatically adjusted by error after the fitting model was applied to the rationality of the adjusted model; subsequently linear fitting is used to determine the reasonable range of subsection based on the detection of continuous unfitting points. From the simulation results, the algorithm is realized in low time complex but with a good data compression effect, and then has a potential practicability.

Autophagy is a cell adaptive response that involves the process of microbial infections. Our previous study has indicated that Bombyx mori nucleopolyhedrovirus (BmNPV) infection triggers the complete autophagic process in BmN-SWU1 cells, which is beneficial to the viral infection. Autophagy-related (ATG) protein ATG13, as part of the ULK complex (a serine-threonine kinase complex composed of ULK1, ULK2, ATG13, ATG101, and FIP200), is the most upstream component of the autophagy pathway, and how it affects virus infections will improve our understanding of the interaction between the virus and the host. This study has determined that the overexpression of the BmAtg13 gene promotes the expression of viral genes and increases viral production in BmN-SWU1 cells, whereas knocking down the BmAtg13 gene suppresses BmNPV replication. Moreover, the BmAtg13 overexpression transgenic line contributed to viral replication and increased mortality rate of BmNPV infection. In contrast, the BmAtg13 knockout transgenic line reduced viral replication 96 h post-infection. Furthermore, BmATG13 directly interacted with viral protein BRO-B, forming a protein complex. Taken together, the findings of this study suggest that BmATG13 may be utilized by the BRO-B protein to promote BmNPV replication and proliferation, which, in turn, provides important insights into the mechanism that autophagy influences viral infection.

The quantum anomalous Hall (QAH) effect is superior to the quantum spin Hall (QSH) effect, which can avoid the inelastic scattering of two edge electrons located on one side of a topological nontrivial material, and thus it has attracted both theoretical and experimental interest. Here, we systematically investigate the lattice structures, and electronic and magnetic properties of hydrogenated arsenene decorated with certain transition metals (Cr, Mo and Cu) based on density-functional theory. A unique QAH effect in Mo@AsH is predicted, whose Chern number (C = 1) indicates only one chiral edge channel located on its one side. Then, we prove that this QAH effect realization is closely related with band inversion, which is the competitive result between its spin–orbit coupling (SOC) strength and exchange field. The quantum state of Mo@AsH can also be tuned by an external strain, similar to SOC, and it is noted that its increased topological gap of about 35 meV under 5.0% tensile strain, is large enough to realize the QAH effect at room-temperature. Additionally, the quantum valley Hall effect in Cu@AsH contributed by the inequality of AB sublattices is also found. Our results reveal the physical mechanism to realize the QAH effect in TM@AsH and provide a platform for electrically controllable topological states, which are highly desirable for nanoelectronics and spintronics.

The structural, mechanical, and electronic properties of four orthorhombic noble-metal nitrides TMN2 (TM = Ru, Rh, Os, and Ir) (space group of Pnnm, No: 58) under 100 GPa were investigated through the first-principles calculation using the generalized gradient approximation within the plane-wave pseudopotential density-functional theory. The obtained equilibrium structures are in excellent agreement with other experimental and theoretical results. The calculated formation energy indicates that the nitrides are thermodynamically metastable but mechanically stable at zero pressure. The calculated B/G ratio indicated RhN2 possesses a ductile nature at 0 GPa, while RuN2, OsN2, and IrN2 are prone to brittleness under pressures of around 20.8, 20.0, and 4.3 GPa, respectively. Then, we calculated the partial and total densities of states. The results show that these four noble-metal nitrides are metallic and the order of metallicity from high to low is: RhN2 > IrN2 > RuN2 > OsN2. Through the charge-density distributions, we find that strong covalency is present in the interstitial dinitrogen units for the four orthorhombic compounds. The calculated hardness of orthorhombic RuN2, RhN2, OsN2, and IrN2 are 13.66, 11.54, 16.33, and 17.92 GPa, respectively. Through the quasiharmonic Debye model, we also investigated the thermodynamic properties of these four compounds.