Computational and experimental studies on band alignment of ZnO/InxGa2-xO3/GaN heterojunctions.

The ZnO/GaN heterojunctions are extensively investigated now, owing to their good luminescent properties and devisable capability to form efficient hybrid structures. An electron-blocking layer inserted into heterojunctions can greatly change their properties. In this work, n-ZnO/ß-InxGa2-xO3/p-GaN heterojunctions have been successfully formed using atomic layer deposition methods. We show that the doping of In can effectively tune the band edges of the heterojunctions. First-principle calculations reveal that the bandgap of bulk ß-InxGa2-xO3 shrinks linearly with the increase in In contents, accompanied by an upward movement of the valence band maximum and a downward movement of the conduction band minimum. As the indium concentrations increase, the valence band offsets show an upward movement at both the InxGa2-xO3/GaN and ZnO/InxGa2-xO3 interfaces, while the conduction band offsets present different trends. A broad, reddish yellow-green emission appears after In doping, which verifies the effect of band alignment. What is more, we show that the amorphization of InxGa2-xO3 can play an important role in tuning the band edge. This work provides access to a series of band offsets tunable heterojunctions and can be used for the further design of direct white light-emitting diodes without any phosphors, based on this structure.

Long Non-Coding RNA HAND2 Antisense RNA 1 Inhibits Colorectal Cancer Development by Sponging microRNA-3118/Leptin Receptor Axis.

OBJECTIVE: This study aimed to examine the function of long non-coding RNA HAND2 antisense RNA 1 (HAND2-AS1) in colorectal cancer (CRC) and explore its underlying mechanism of action. METHODS: HAND2-AS1, microRNA (miR)-3118, and leptin receptor (LEPR) levels were determined using western blot analysis and reverse transcription quantitative polymerase chain reaction (RT-qPCR). RNA-binding protein immunoprecipitation (RIP) and luciferase reporter assays were performed to evaluate the relationship between HAND2-AS1, miR-3118, and LEPR. Overexpression of genes in CRC cell lines was performed by transfection with the overexpression vector or miR-mimic. Cell proliferation, migration, and apoptosis-related protein levels were evaluated using the Cell Counting Kit-8 (CCK-8), Transwell, and western blotting assays. A CRC xenograft mouse model was established to verify the role of HAND2-AS1 in CRC in vivo. RESULTS: In both CRC cell lines and CRC tumor samples the HAND2-AS1 expression was reduced. Upregulation of HAND2-AS1 levels inhibited CRC cell line proliferation and migration, initiated apoptosis, and suppressed the growth of CRC xenografted tumors. In addition, HAND2-AS1 sponges miR-3118, which is up-regulated in CRC. Moreover, miR-3118 overexpression promoted CRC cell line proliferation along with cell migration, but hindered apoptosis of cells, along with altering the consequences of high expression levels of HAND2-AS1 in CRC cells. In addition, miR-3118 can target LEPR, which is downregulated in CRC. The effect of miR-3118 on CRC cells was blocked by LERP overexpression. CONCLUSION: HAND2-AS1 effectively inhibited CRC progression by sponging the miR-3118-LEPR axis. Our results may facilitate the development of therapeutic interventions for CRC.

The structural, electronic and optical properties of four α-Se-based heterostructures with hyperbolic characteristics.

The physical properties and potential applications of two-dimensional (2D) materials can be effectively modulated and enriched by constructing van der Waals heterostructures (VDWHs) with two or more 2D monolayer materials. In this work, by using first-principles calculations based on density functional theory (DFT), we have systematically investigated the structural, electronic and optical properties of four α-Se-based VDWHs, that is, α-Se/Ca(OH)2, α-Se/GaSe, α-Se/h-BN and α-Se/MoS2 VDWHs. The results show that both the band alignment and band gap of these four VDWHs can be effectively modulated by interlayer coupling, biaxial strain and an external electric field. Compared with interlayer coupling and biaxial strain, the external electric field can modulate the electronic properties of these VDWHs more significantly, which makes them exhibit more rich electronic properties. Interestingly, the optical property calculations revealed that both α-Se and the four α-Se-based VDWHs have intrinsic hyperbolic properties. In addition, compared with the individual components, the optical absorption of these four VDWHs in the visible and ultraviolet light regions is significantly enhanced. These results enrich the properties of selenene and selenene-based VDWHs and extend their potential applications in electronic and optoelectronic devices.

CircCDC6 restrains tumor growth and glycolysis energy metabolism in colorectal cancer via regulating miR-3187-3p and downstream PRKAA2.

The aberrant downregulation of circCDC6 in colorectal cancer (CRC) was previously identified by circRNA microarray analysis. However, the detailed role of circCDC6 in CRC is still lacking. We thus investigated the function of circCDC6 in CRC. The expression of circCDC6, miR-3187-3p and PRKAA2 mRNA was checked by real-time quantitative PCR (RT-qPCR). Cell growth was evaluated by MTT, EdU and colony formation assays. Cell apoptosis was evaluated by flow cytometry. Glycolysis was evaluated by glycolysis stress test and lactic acid level. The expression of PRKAA2, HK2 and LDHA proteins was checked by western blotting. The potential binding between miR-3187-3p and circCDC6 or PRKAA2 was confirmed by dual-luciferase reporter assay, RIP assay and pull-down assay. Xenograft model was established in nude mice. CircCDC6 showed poor expression in CRC tumor samples and cells. CircCDC6 ectopic expression repressed CRC cell proliferation, survival and glycolysis energy metabolism. MiR-3187-3p was targeted by circCDC6, and miR-3187-3p depletion also repressed CRC cell growth and glycolysis. PRKAA2 was a downstream target of circCDC6/miR-3187-3p pathway, and circCDC6 upregulated PRKAA2 expression via targeting miR-3187-3p. PRKAA2 knockdown rescued the functional effects of circCDC6 ectopic expression. CircCDC6 overexpression in vivo impeded tumor development in animal models. CircCDC6, acting as a tumor inhibitor, repressed tumor growth and glycolysis metabolism in CRC via targeting the miR-3187-3p/PRKAA2 axis, which partly clarified the role of circCDC6 in CRC.

Formation of stable polonium monolayers with tunable semiconducting properties driven by strong quantum size effects.

Elemental two-dimensional (2D) materials have attracted extraordinary interest compared with other 2D materials over the past few years. Fifteen elements from group IIIA to VIA have been discussed experimentally or theoretically for the formation of 2D monolayers, and the remaining few elements still need to be identified. Here, using first-principles calculations within density functional theory (DFT) and ab initio molecular dynamics simulations (AIMDs), we demonstrated that polonium can form stable 2D monolayers (MLs) with a 1T-MoS2-like structure. The band structure calculations revealed that polonium monolayers possess strong semiconducting properties with a band gap of ∼0.9 eV, and such semiconducting properties can well sustain up to a thickness of 4 MLs with a bandgap of ∼0.1 eV. We also found that polonium monolayers can be achieved through a spontaneous phase transition of ultrathin films with magic thicknesses, resulting in a weaker van der Waals interaction of ∼32 meV Å-2 between each three atomic layers. Also, the underlying physics comes from layered Peierls-like distortion driven by strong quantum size effects. Based on these intriguing findings, a suitable substrate on which the polonium monolayer can be grown through an epitaxial growth technique is proposed for further experiments. Our work not only extends completely the puzzle of elemental 2D monolayer materials from group IIIA to VIA, but also presents a new formation mechanism of 2D materials beyond the database of bulk materials with layered van der Waals interactions.

Equally Spaced Quantum States in van der Waals Epitaxy-Grown Nanoislands.

Pursuing the confinement of linearly dispersive relativistic Fermions is of interest in both fundamental physics and potential applications. Here, we report strong STM evidence for the equally spaced, strikingly sharp, and densely distributed quantum well states (QWSs) near Fermi energy in Pb(111) nanoislands, van der Waals epitaxially grown on graphitized 6H-SiC(0001). The observations can be explained as the quantized energies of confined linearly dispersive [111] electrons, which essentially "simulate" the out-of-plane relativistic quasiparticles. The equally spaced QWSs with an origin of confined relativistic electrons are supported by phenomenological simulations and Fabry-Pérot fittings based on the relativistic Fermions. First-principles calculations further reveal that the spin-orbit coupling strengthens the relativistic nature of electrons near Fermi energy. Our finding uncovers the unique equally spaced quantum states in electronic systems beyond Landau levels and may inspire future studies on confined relativistic quasiparticles in flourishing topological materials and applications in structurally simpler quantum cascade laser.

Do policy burdens induce excessive managerial perks? Evidence from China's stated-owned enterprises.

This paper explores the effect of policy burdens of China's state-owned enterprises (SOEs) on senior executives' excessive perks. The empirical analysis demonstrates that SOE policy burdens are significantly and positively correlated with senior executives' excessive perks, indicating that SOE policy burdens increase agency cost. The results hold after controlling for potential endogeneity. Moreover, we find the following evidences. Strategic policy burdens of SOEs have a significantly greater impact on their senior executives' excessive perks, compared with social policy burdens. The positive impact of SOE policy burdens on excessive perks is significantly weaker in east China due to the higher degree of marketization. The central government's stricter supervision can also alleviate the positive correlation between policy burdens of centrally administered SOEs and senior executives' excessive perks.

Catalytic hydrothermal liquefaction of rice straw for production of monomers phenol over metal supported mesoporous catalyst.

The catalytic (SBA-15, Ni/SBA-15, Al/SBA-15 and Ni-Al/SBA-15) hydrothermal liquefaction (HTL) of rice straw biomass was examined at different temperature with different amount of catalyst in the presence of different solvents. In comparison with water solvent liquefaction, the bio-oil yield significantly increased under alcoholic solvent (ethanol and methanol). The highest bio-oil yield was observed for water (44.3 wt%) with Ni-Al/SBA-15, while for ethanol (56.2 wt%), and for methanol (48.1 wt%) with, Ni/SBA-15 catalyst. The loading of Ni and Al on SBA-15, the acid strength of the catalyst enhanced. Bio-oils yield were analyzed with the help of GC-MS, FT-IR, NMR, GPC and CHNS. From the GC-MS analysis, the main monomeric phenolic compounds were produced, phenol, 4-ethyl-phenol, 2-methoxy-phenol, 2-methoxy-4-ethyl-phenol and Vanillin. It was observed by CHNS and GPC analysis of the bio-oil, compared to the non-catalytic liquefaction reaction, the catalytic liquefaction reaction promotes the hydrogenation/hydrodeoxygenation and produced lower molecular weight bio-oils.

Prevalence of pneumoconiosis among young adults aged 24-44 years in a heavily industrialized province of China.

OBJECTIVES: The purposes of this study were to clarify (i) the prevalence of pneumoconiosis among young adults and (ii) the factors associated with pneumoconiosis among young adults to explore targeted solution for control of pneumoconiosis among young adults (aged 24-44 years). METHODS: The new cases diagnosed from 2001 to 2015 (extracted from the National Occupational Disease and Occupational Health Information Monitoring System) were involved in this research, including information of employer, patient's name, date of birth, gender, date of diagnosis, first year of dust exposure, duration of exposure, aggregation etc RESULTS: A total of 1519 pneumoconiosis cases were diagnosed among young adults (21.6% of overall cases). Silicosis was the most common type with acute process of disease. Compared with overall cases, the young patients had shorter duration of exposure, more stage II/III cases and higher aggravation rate; and were even more concentrated in small and medium enterprises where more migrant workers were employed and insufficient protective measures were used. Without further regulation, the prevalence of pneumoconiosis among young adults would bring not only disease suffering for 3000 individuals and their families, but also an annual economic loss up to 180 million yuan for Hebei province till 2025. CONCLUSIONS: As a typical heavily industrialized province of China, Hebei has severe situation on pneumoconiosis among young adults. Special attention and effort on silica-contacting industries, small and medium enterprises, and migrant workers should be focused in future occupational supervision and regulation among young adults.

A novel nitrogen heterocycle platform-based highly selective and sensitive fluorescence chemosensor for the detection of Al3+ and its application in cell imaging.

In the study, a highly selective and sensitive fluorescence sensor derived from nitrogen heterocycle was synthesized and characterized. By the fluorescence experiments, it was found to show a higher response toward Al3+ than other commonly coexistent metal ions in C2H5OH/H2O media (pH = 7.2). Moreover, the large binding constant (3.44 × 1014 M-1) between Al3+ and the sensor was calculated by fluorescence titration experiment. In addition, the synergistic effect mechanism due to photoinduced electron transfer (PET) and C[double bond, length as m-dash]N isomerization was deduced according to the fluorescence behavior. In addition, the fluorescence imaging in living cells was studied systemically, which exhibited high fluorescence sensing activity toward Al3+.