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In this paper, the effects of the thermostability, band structure, and the external electric field on the electronic structure of MoSe2/Arsenene heterojunction are calculated based on the density functional theory. The calculation results show that the MoSe2/Arsenene heterojunction is a type-II heterojunction with a band gap of 0.89 eV. When MoSe2 and Arsenene combine by van der Waals force, the electrons are transferred from MoSe2 to Arsenene, the holes are transferred from Arsenene to MoSe2, with the direction of the internal electric field from MoSe2 to Arsenene. The MoSe2/Arsenene heterojunction with valence band top and conduction band bottom contributed by Arsenene and MoSe2, respectively, show excellent thermostability at room temperature. The external electric field can effectively modulate the electronic structure of heterojunction. When the electric field is negative, electrons are transferred from MoSe2 to Arsenene and holes from Arsenene to MoSe2. The Fermi level of Arsenene moves down while that of MoSe2 moves up, with a decreased band gap of the MoSe2/Arsenene heterojunction. When the electric field is positive, the direction of electron and hole transfer are opposite to that when the electric field is negative. The Fermi energy level of Arsenene and MoSe2 also move in the opposite direction, with a first increased then decreased band gap of MoSe2/Arsenene heterojunction. As the electric field increases, the heterojunction eventually transforms from type-II to type-III, achieving the transition from semiconductor to metal.

The effects of B, N, and BN doping of arsenene and different strains on the stability, electronic structure, and optical properties of BN-doped arsenene were investigated using a first-principles approach. It was found that B, N, and BN doping caused the bandgap of arsenene to shift from indirect-direct, and strong charge transfer occurred between arsenene and B, N, and BN, and the transfer between N atoms and arsenene was more intense. The binding energy of the BN-doped arsenene system is always negative at different strains and in a stable state, but the stability of the structure is gradually decreasing. The bandgap of the BN-doped arsenene system shows a trend of decreasing, then increasing, and then decreasing under different tensile and compressive deformations. The only difference is that the tensile deformation continues to increase the bandgap at 2%, while the compressive deformation decreases the bandgap. The p-state electrons of the As atom near the Fermi energy level make the main contribution to the BN-doped arsenene system, and the p-state electrons of the B atom have some contribution. Red shifting occurs at the absorption and reflection peaks for doped systems with tensile deformation of 1% to 5%, and the absorption and reflection peaks for doped systems with compressive deformation of - 1% to - 5%.

The structural stability, electronic structure, and optical properties of BN-doped black phosphorene systems at different concentrations were investigated using a density generalized theory approach based on the first principles. It was found that BN-doped black phosphorene was more stable compared with B and N atom doping. With the increase of doping concentration, the stability of the structure gradually decreases, and the structure of the system with 25% doping concentration is the most stable. The intrinsic and N-doped black phosphorene are direct bandgap semiconductors, and B and BN doping make the black phosphorene change from direct bandgap to indirect bandgap. The total density of states is mainly contributed by the p-state electrons of the B and P atoms, and the N atoms have a role in the local density of states with little contribution to the overall one. The black phosphorene undergoes charge transfer between the B and N atoms. The amount of charge transfer increases with the increase of doping concentration. The BN-doped black phosphorene system is blue-shifted at the absorption and reflection peaks compared to the intrinsic black phosphorene system. The doping makes the dielectric function peaks are shifted to the high energy direction, which leads to an increase in the intensity of the electric field generated by light, which is beneficial to improve the efficiency of photovoltaic power generation, and the peak of photoconductivity is slightly reduced and shifted to the low energy direction, which is more favorable to the leap of photons, with the most obvious performance when the BN doping concentration is 12.5% and 25%.

Based on first-principles calculations, the electronic structure and optical properties of the Mo-doped monolayer rhenium disulfide (ReS2) model are calculated, as well as the system stability, bond length, charge difference density, band structure, photoabsorption coefficient, system stability, and reflectivity are analyzed. The calculation results show that doping changes the structural stability of the system, which gradually decreases with an increasing concentration of doping. The calculation of bond structure and density of states is indicated that the band gap value of the system decrease continuously to zero with increasing doping concentration, while the average charge population of atoms at doping sites keeps increasing with the better electron-losing ability of atoms. Compared with the intrinsic monolayer ReS2, the peak of systemic reflectivity at different doping concentrations has corresponding degrees of redshift in a certain wavelength range, as demonstrated by the optical properties.

To solve the problems of missed detection, repeated detection and low precision in the process of subpixel corner point detection of black-and-white checkerboard used for calibrating microscopic devices in complexed industrial environment, a new detection method based on greyscale constraint on the four-neighbourhood diagonal was proposed in the paper. By analysing geometric characteristics of the four-neighbourhood region and the grayscale features in diagonal direction, the SINC greyscale distribution was adopted to constrain corner point position, which realised rapid detection of subpixel corner point. Comparing with the existing methods, in the new method proposed the rate of repeated detection and missed detection decreased by about 20% and 2% respectively, which achieved a high rate of detecting accuracy over 99.9%. Meanwhile, the maximum error of corner point detection lowered from ±0.6pix to ±0.3pix, which showed that precision improved by about 50%. Finally, microscopic calibrating experiments used for micro-hole centring system were carried out. The results show centring error was reduced from 10 μm (before calibration) to 3 μm (after calibration), and centring precision was increased by about 75%. It demonstrated that the new method improved the accuracy and precision effectively, which verified its applicable feasibility of microscopic calibration used in industry spots.

The electronic structure and optical properties of the black phosphorene adsorbed O-atom system were studied by the method based on the first principle of density generalised theory with different ...

The effects of bend angle on the stability, electronic structure and optical properties of Li-absorbed borophene system are studied by using density functional theory based on the first principles....

Based on first-principles calculations using density functional theory, this paper systematically studies the effects of uniaxial tension-compression deformation on the stability and electrical and thermal properties of monolayer graphene and AA stacked bilayer graphene. The study shows that the original symmetry of graphene is broken by the tensile and compression deformations, catalyzing the interlayer coupling of bilayer graphene. Its electronic energy band, phonon dispersion, and other physical properties have changed. The transition from metalloid to semiconductor has completed since the deformation weakens the stability of the graphene system to varying degrees and opens the band gap of monolayer graphene. The band gap becomes larger with the increase of tensile and compressive deformation, in which way it can be adjusted. Influenced by the tiny tensile deformation, metalloid properties are exhibited by a small band gap of intrinsic AA-stacked bilayer graphene, and then the band gap becomes larger as the deformation increases. A band gap appears in the system phonon dispersion curves when the compression deformation increases to -15%. The phonon mode softens and shows virtual frequency. The value of virtual frequency increases with the increase of compression deformation. At the very moment, the vibration mode is discontinuous, and the system is unstable.

In this paper, the first-principles method is used to systematically study the influence of compressive deformation on the oxygen adsorption and electrical properties of phosphorene surface and the related mechanism. According to results, the position located on the top of phosphorus atom has the strongest adsorption energy for oxygen atoms comparing with other positions, which makes the phosphorene surface susceptible to oxidation. Moreover, when the compressive ratio reaches to 15% of the lattice constant along armchair direction, the oxygen adsorption energy of phosphorene is the weakest. According to the calculation results of the partial density of states and the differential charge density, when the compressive ratio reaches to the extreme point, the phosphorus atom has the lowest density of states at the Fermi level, which also presents the lowest physical and chemical activity. In the meanwhile, the results also show the oxygen atom has the smallest amount of electron loss on the phosphorene surface, which also means the lowest oxygen adsorption energy of phosphorus. The energy band structure calculations show that the phosphorene is a semiconductor with a direct band gap of 1.461eV. Furthermore, the energy band gap width is significantly reduced with the increase of the compressive ratio, which will lead to the direct band gap change into an indirect band gap, and the phosphorene is changed to be a conductive state.

Background Mild cognitive impairment (MCI) is a high-risk factor for Alzheimer's disease (AD). In the present study, we investigated the association of genetic polymorphisms of five genes (8-oxoguanine DNA glycosylase 1 (OGG1), bridging integrator 1 (BIN1), sortilin-related receptor 1 (SORL1), presenilin 2 (PSEN2) and nerve growth factor (NGF)) with MCI risk in a Xinjiang Uygur population. We also tested the relationship between the promoter methylation of genes OGG1 and dihydrolipoamide S-succinyltransferase (DLST) with MCI. Methods This study involved 43 MCI patients and 125 controls. Genotyping was done by Sanger sequencing. DNA methylation assays used quantitative methylation-specific polymerase chain reaction. Results We found that polymorphisms of five genes and the methylation of DLST and OGG1 genes were not associated with MCI (P > 0.05). Further subgroup analysis found that DLST hypomethylation was significantly associated with MCI in the carriers of apolipoprotein E (APOE) e4 (P = 0.042). In the carriers of non-APOE e4, DLST methylation levels were significantly lower in the male control group than in the female control group (p = 0.04). Meanwhile, among the non-APOE e4 carriers younger than 75, OGG1 hypermethylation levels were significantly associated with MCI (P = 0.049). DLST methylation in female controls was significantly lower than that in male controls (P = 0.003). According to gender stratification, there was a significant positive correlation of fasting plasma glucose (FBG) and high-density lipoprotein (HDL) with OGG1 methylation in the female controls (FBG: P = 0.024; HDL: P = 0.033). There was a significant inverse correlation between low-density lipoprotein and DLST methylation in male MCI (P = 0.033). There was a significant positive correlation between HDL and DLST methylation levels in the female controls (P = 0.000). Conclusions This study was the first to discover that DLST promoter methylation interacted with APOE e4 and thus affected the pathogenesis of MCI. In addition, OGG1 promoter methylation interacted with several other factors to increase the risk of MCI.

To solve these problems (i.e. the accuracy rate and stability of the centering) of enabling secondary machining of micro-holes with a size of 0.1 to 1 mm in high-performance metal alloy parts, a non-standard nested circle-fitting least-square method, with a linear constraint passing through the center (least square method with linear constraint [LSLC]), is proposed in this article. The experimental results show that the center of the circle is fitted with a maximum deviation of ±1.5 µm and good fitting precision, compared to other existing approaches. At the same time, the accuracy rate is increased by at least 20%, delivering a result of more than 99%, so the accuracy of the fitting and the stability of the centering are significantly improved. Finally, the new method is applied in actual micro-hole electrochemical deburring study. With the overall goal of ensuring centering, a rough-and-fine deburring process has been explored. On the premise that the hole is not expanded, the burrs have been quickly and completely removed, and machined surface roughness, Ra, has also reduced from 1.2 to 0.52 µm. The experiment has provided concrete validation of the feasibility of the nested circle-fitting method we have proposed.

The effects of tensile deformation on the stability and electronic structure of the O adsorbed graphyne system is studied by using density functional theory based on the first-principles. It is found that in the current research range, the tensile deformation causes the structural stability of the intrinsic graphyne to decrease slightly, but the stability of the O adsorbed graphyne system increases. Compared with the undrawn stretching system, the adsorption energy of the O adsorbed graphyne system which is subjected to stretching increases. The adsorption energy is high in small deformation. Then the adsorption energy becomes smaller as the tensile deformation increases. It is proved that the tensile deformation can exacerbate the adsorption of O atoms. After the intrinsic graphyne is subjected to stretching, the band gap decreases as the tensile deformation increases. The graphyne is changed from a medium band gap semiconductor to a small band gap semiconductor. After the graphyne adsorbs the O atom, the C atom which is closest to the O atom is pulled up, the plane of the graphyne is twisted, the band gap of the graphyne is reduced, and a new impurity level is introduced at the Fermi level. The adsorption of graphyne on O atoms belongs to the category of chemical adsorption, and C atoms have stable bonding. There is a strong electron transfer between them, causing the Fermi level to move. Compared with the density of states of the graphyne, multiple density peaks appear in the density of states. A very pronounced energy gap has also appeared near the energy level of −18 eV. After applying uniaxial tensile deformation, the band gap is reduced from 0.263 eV to 0 eV, exhibiting the Dirac cone, corresponding to the metalloid properties.

The effect of bend angle on the stability, electronic structure and optical properties of S absorbed graphene system is studied by using density functional theory based on the first - principles. Within the scope of the current study, it is found that the C atoms which are closest to the S atom are pulled up, the graphene plane is distorted, and the band gap of the graphene is opened, which changes graphene from quasi-metal to semiconductors. Bending deformation decreases the structural stability of S atom adsorbed on graphene system. The adsorption energy decreases with the increase of bending angle. After the intrinsic graphene is bent, the band gap is opened, and the bandgap increases with the bending angle. When the bending angle is between 0°–20°, it still corresponds to the quasi-metal property. When the bending angle increases to 25°, it gradually changes from small bandgap semiconductor to medium bandgap semiconductor. The band gap of graphene adsorbed S atom system decreases with the increase of the bending angle, and it always corresponds to medium bandgap semiconductors. When the angle is increased to 30°, the system loses its stability. The rate of increase of absorption coefficient increases with the increase of bending angle. The deformation causes the maximum absorption peak and the maximum reflection peak of the system to red shift, and the degree of red shift increases with the increase of the bending angle.

The CASTEP program based on density functional theory was used to study the effect of shear deformation on the structure, electronic and optical properties of hydrogenated silicene. The calculation results show that the hydrogenated silicene can still remain stable under the action of shear deformation. After the hydrogenation of silicene, the forbidden band width increases to 2.204 eV, and the electrical conductivity is significantly improved. Shear deformation significantly affects the energy band structure characteristics of hydrogenated silicene. The resulting band gap gradually decreases as the deformation increases. The shear deformation causes the red shift of the imaginary part of the dielectric function of the hydrogenated silicene to the direction of lower energy. Shear deformation improves the luminous efficiency of the system. The peak range of the reflection spectrum gradually widens with the increase of the deformation. These properties may be applied to optoelectronic devices in the future.

The aim of the work was to investigate the mechanism of cracking of n-heptane in the presence of a medium-pore finely crystalline catalyst based on zeolite ZSM-5 and the development of a kinetic model of the mechanism of the thermic and catalytic reaction. The catalyst based on zeolite ZSM-5 has high catalytic activity for the catalytic cracking of n-heptane, high stability, and long life time. The kinetic model includes 12 chemical substances and 11 reactions. The values predicted by the model were in good agreement with the experimental data, and the average relative error in the main products was not greater that 10%. The model showed good agreement between the calculated yields of the final product and the experimental data for the catalytic cracking of n-heptane.

Silicene has important applications in the field of nanoelectronics due to its superior electronic properties. Based on the density functional theory, the influence of shear deformation on the electronic structure and optical properties of Al absorbed silicene system is studied by using the first-principles calculations. The results show that the most stable adsorption sites of double aluminum atoms on the surface of silicene are top and valley. After silicene adsorbs aluminum atoms, the silicene around the Al atoms attains different degrees of distortion. The analysis of the electron band structure and the density of states shows that after adsorption of Al atoms, the band gap of silicene increases. As the degree of shear deformation increases, the band gap of the adsorption system gradually decreases. Shear deformation causes the highest absorption peak and the highest reflection peak of the adsorption system to redshift, and the degree of redshift increases with the increase of displacement.

// Xiaoying Chen 1 , Yong Yang 1 , Jing Liu 1 , Bin Li 1 , Yan Xu 1 , Cong Li 2 , Qi Xu 2 , Guili Liu 1 , Yingmin Chen 1 , Jieer Ying 2 , Shiwei Duan 1 1 Medical Genetics Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China 2 Department of Medical Oncology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310022, China Correspondence to: Shiwei Duan, email: duanshiwei@nbu.edu.cn Jieer Ying, email: jieerying@aliyun.com Keywords: gastric cancer, N-Myc downstream regulated gene 4, DNA methylation, prognosis, diagnosis Received: September 27, 2016 Accepted: November 23, 2016 Published: December 22, 2016 ABSTRACT In order to assess whether N-Myc downstream regulated gene 4 ( NDRG4 ) methylation was associated with the diagnosis and prognosis of gastric cancer, we measured the methylation of NDRG4 promoter and gene body regions among 110 gastric cancer patients using quantitative methods (MethyLight and pyrosequencing). Both NDRG4 promoter and gene body methylation levels were increased in tumor tissues than paired adjacent normal tissues ( P < 0.001). NDRG4 gene body methylation was found to be significantly associated with age and tumor differentiation. NDRG4 promoter hypermethylation was proved to be a predictor of poor overall survival. However, opposite result was observed among The Cancer Genome Atlas (TCGA) cohort. The findings from gastric cell lines and public databases have suggested that NDRG4 methylation level was inversely associated with NDRG4 transcription level. Subsequent luciferase reporter gene assay showed that promoter CpG island but not gene body CpG island was able to upregulate gene expression. Collectively, NDRG4 promoter hypermethylation contributed to the risk of gastric cancer and predicted a poor prognosis in Chinese gastric cancer patients. Moreover, the combined methylation levels of NDRG4 promoter and gene body served as diagnostic biomarkers in gastric cancer.

Supplemental Digital Content is available in the text, Our study investigated the association of five genes with MCI in the Xinjiang Uygur population in China. In addition, we also analyzed the association between APOE methylation and MCI. Forty-three MCI and 125 controls were included in the present study. Genotyping was done by Sanger sequencing. DNA methylation assay was done using quantitative methylation-specific polymerase chain reaction (qMSP). The distribution of HMGCR rs3846662 allele frequencies was significantly different between the MCI group and the control group (P = .04), especially in women (P = .032). Subgroup analysis showed that there was a statistically significant association of HMGCR rs3846662 with MCI in the non-APOE ε4 group (P = .024), especially in the females with non-APOE ε4. Similarly, HMGCR rs3846662 genotype and allele frequency in the ApoE E2 protein group were significantly different in the MCI group and the control group (genotype P = .021; allele P = .007). In addition, SIRT1 rs7895833 genotype frequency in the APOE ε4 group was found to be significantly different between the MCI and the control group (P = .005). We also observed a significant association of SIRT1 rs7895833 with MCI in the ApoE E4 protein subgroup (P = .005). In addition, APOE methylation levels were significantly different between the MCI group and the control group (P = .021), especially in men (P = .006). Subgroup analysis showed that APOE methylation levels were significantly associated with MCI in the non-APOE ε4 group (P = .009), especially in men (P = .015). This study found a significant association of HMGCR rs3846662 with MCI in females independent of APOE ε4. In contrast, we revealed that the association of SIRT1 rs7895833 with MCI was dependent on with APOE ε4. We also showed that hypermethylation of APOE in MCI was independent of APOE ε4.

Based on the density functional theory, the influence of shear deformation on the electronic structure and optical properties of Li absorbed silicene system is studied by using the first-principles calculations. In the current research scope, it was found that after silicene adsorbs Li atoms, the silicene around the Li atoms has different degrees of distortion, and the band gap of the silicene increases. The calculation of binding energy shows that the shear deformation has little effect on the structural stability of Li absorbed silicene system. After intrinsic silicene shear deformation, the band gap increases with the increase of shear deformation.The band gap of Li absorbed silicene system decreases with the increase of shear deformation. The shear deformation causes the maximum absorption peak and the maximum reflection peak of the adsorption system to red shift.

Aberrant promoter methylation of multiple genes is associated with various diseases, including Alzheimer's disease (AD). The goal of the present study was to determine whether dopamine receptor D4 (DRD4) promoter methylation is associated with AD. In the current study, the methylation levels of the DRD4 promoter were measured in 46 AD patients and 61 controls using bisulfite pyrosequencing technology. The results of the present study demonstrated that DRD4 promoter methylation was significantly higher in AD patients than in controls. A further breakdown analysis by gender revealed that there was a significant association of DRD4 promoter methylation with AD in males (23 patients and 45 controls). In conclusion, the results of the present study demonstrated that elevated DRD4 promoter methylation was associated with AD risk in males.

Catalytic pyrolysis is a promising technology to produce light olefins. Gibbs free-energy minimization method was used to study the thermodynamic equilibrium distribution of olefins in catalytic pyrolysis with Aspen Plus software. The result showed that olefin systems with different carbon numbers demonstrated a similar thermodynamic equilibrium distribution. The ethene equilibrium composition increased with increasing reaction temperature and decreased with increasing total hydrocarbon pressure. By contrast, the propene equilibrium composition reached a maximum of 40 wt% at 850–950 K under 0.1 MPa. Ethene yield and propene yield of thermodynamic equilibrium, catalytic pyrolysis and thermal pyrolysis were compared. The use of catalyst greatly increased the yields of ethene and propene, but the yields were still lower than the equilibrium data. Catalytic pyrolysis was carried out in the interaction zone where both catalytic conversion and thermal conversion were important. Propene yield was close to ethene yield at about 950 K from the thermodynamic view. Given the shape-selective effect of the catalyst on branched olefins with large carbon number, the equilibrium carbon number distribution of olefins possibly shifted from large carbon numbers to low carbon numbers, resulting in enhanced ethene and propene yields.

As a member of the neurotrophic factor family, brain derived neurotrophic factor (BDNF) plays an important role in the survival and differentiation of neurons. The aim of our work was to evaluate the role of BDNF promoter methylation in drug addiction. A total of 60 drug abusers (30 heroin and 30 methylamphetamine addicts) and 52 healthy age- and gender-matched controls were recruited for the current case control study. Bisulfite pyrosequencing technology was used to determine the methylation levels of five CpGs (CpG1-5) on the BDNF promoter. Among the five CpGs, CpG5 methylation was significantly lower in drug abusers than controls. Moreover, significant associations were found between CpG5 methylation and addictive phenotypes including tension-anxiety, anger-hostility, fatigue-inertia, and depression-dejection. In addition, luciferase assay showed that the DNA fragment of BDNF promoter played a key role in the regulation of gene expression. Our results suggest that BDNF promoter methylation is associated with drug addiction, although further studies are needed to understand the mechanisms by which BDNF promoter methylation contributes to the pathophysiology of drug addiction.

Previous studies have suggested that increased opioid receptor κ1 (OPRK1) and opioid receptor δ1 (OPRD1) methylation levels are involved in Alzheimer's disease (AD). In the present study, the methylation levels of two opioid receptor genes, opioid receptor µ1 (OPRM1) and opioid related nociceptin receptor 1 (OPRL1), were analyzed for their association with AD. Gene methylation levels were measured using bisulfite pyrosequencing in DNA samples derived from blood samples of 51 AD patients and 63 controls. The results indicated that there were significantly elevated promoter methylation levels of OPRM1 and OPRL1 in AD (OPRM1: P=0.007; OPRL1: P=2.987x10‑6). Dual‑luciferase reporter gene assays demonstrated that the promoter fragments of these two genes were able to promote gene expression (OPRM1: Fold‑change=2.616, P=0.003; OPRL1: Fold change=11.395, P=0.007). In addition, receiver operating characteristic analyses further indicated that a methylation panel of four opioid receptor genes (area under the curve=0.848, sensitivity=0.723, and specificity=0.879) performed well in the prediction of AD. These results suggested that opioid receptor genes may be used as potential methylation biomarkers for the diagnosis of AD.

Alzheimer's disease (AD) is a neurodegenerative disorder leading to progressive memory and cognitive impairment. Previous studies have identified multiple genes associated with AD. The aim of the present study was to validate the association of the five AD-associated variants, 8-oxoguanine DNA glycosylase 1 (OGG1) rs1052133, bridging integrator 1 rs744373, sortilin-related receptor 1, rs1133174, presenilin 2 rs8383, and nerve growth factor rs6330, in the Xinjiang Chinese population. In addition, the present study evaluated the contribution of the promoter methylation of two genes, OGG1 and dihydrolipoamide succinyltransferase (DLST) to the risk of AD. A total of 17 AD cases and 34 controls were recruited from Xinjiang province in China. Genotyping was done by Sanger sequencing. DNA methylation assay was performed using quantitative methylation specific polymerase chain reaction. The study was unable to repeat the previous association of the five genetic polymorphisms with AD. However, DLST methylation levels were demonstrated to be significantly decreased in AD patients (P=0.027), particularly in female AD patients (P=0.025). Subgroup analysis by apolipoprotein E (APOE e4) genotype demonstrated that OGG1 methylation levels were significantly increased in APOE non-e4 carriers compared with APOE e4 carriers (P=0.027). In summary, the present study reported that DLST hypomethylation was significantly associated with AD in females, and that OGG1 promoter methylation may interact with APOE e4 genotype.