Designing novel monolayer and multilayer h-CSe crystals with tunable photoelectric properties.

Using the first-principles method, a new structure of monolayer h-CSe was predicted, exhibiting good dynamical and thermal stability. The geometrical, electronic and optical properties of monolayer h-CSe are examined at the HSE level. Furthermore, the influences of the in-plane strain and layer number on the electric properties of the two dimensional h-CSe material are studied. The results indicate that it possesses an indirect band gap, which exhibits a rich variety of behaviors depending on the small in-plane biaxial strain. The band gap of monolayer h-CSe could be easily tuned in the energy range from 0.82 eV to 2.61 eV under small in-plane biaxial strain (from -3% to 3%). Also, a band gap transition between direct and indirect types is not found. The band gap of the h-CSe materials decreases with the increase of their layer number. In addition, it was found that these h-CSe materials show excellent optical properties, including strong light harvesting ability for the ultra-violet light range of the solar spectrum. The results obtained here indicate that monolayer h-CSe may have significant potential applications in future nanoelectronic fields.

Risk Factor Analysis of Hepatic Encephalopathy and the Establishment of Diagnostic Model.

To identify laboratory diagnostic indicators of hepatic encephalopathy (HE), the present study established a HE diagnostic model to explore the diagnostic value of serum homocysteine, lactic acid, procalcitonin, and bile acid levels in HE identification. 371 patients with liver cirrhosis were selected as research objects, who were admitted to the Department of Hepatic Diseases, Affiliated Hospital of Northwest Minzu University from August 2019 to August 2020. The Spearman correlation results indicated that between lactic acid, procalcitonin, bile acid, serum homocysteine, and HE, the coefficients were -0.15, 0.41, 0.29, and -0.19, respectively. Univariate and multivariate analysis methods were adopted for inpatient analysis to identify the influencing factors of HE occurrence, and the diagnosis of the HE identification model was subsequently constructed. The univariate logistic regression showed that risk of developing HE increased as bile acid level (P = 0.00434) and serum homocysteine (P = 0.058) increased. Multivariate logistic regression diagnostic model of bile acid level and serum homocysteine revealed that the AUC value of the area under the ROC curve was 0.7201, indicating that the diagnostic model produced a satisfactory evaluation effect. The model formula referred logistic (P) = -2.4544 + 0.0117 bile acid levels + 0.0198 serum homocysteine. In this study, the HE diagnostic model was established using logistic regression analysis, which could benefit patients in early HE differential diagnosis. Particularly, combined detection of serum homocysteine and bile acid levels was considered to be more significant.

Two-dimensional aluminum phosphide semiconductor with tunable direct band gap for nanoelectric applications.

More and more attractive applications of two-dimensional (2D) materials in nanoelectronic devices are being achieved successfully, which promotes the rapid and extensive development of new 2D materials. In this work, the structural and electronic properties of the V structure aluminum phosphide (V-AlP) monolayer are examined by density functional calculations, and its electronic properties under strain and an electric field are also explored in detail. The computation results indicate that it has good stability. Interestingly, it possesses a wide direct gap (2.6 eV), and its band gap exhibits a rich behavior depending on the strain, E-field and layer stacking. Under biaxial strain, its band gap can be tuned from 1 eV to 2.6 eV. And a direct-indirect band gap transition is found when external tension is applied. The V-AlP monolayer also exhibits anisotropic behavior as its band structure variation trends under strains along different directions are obviously different. When the external E-field is changed from 0.5 V Å-1 to 1 V Å-1, the band gap of the V-AlP monolayer can be tuned linearly from 0 eV to 2.6 eV. Layer stacking narrows the band gap of the 2D V-AlP material. It is concluded that strain, E-field and layer stacking can all be used effectively to modify the electronic property of the V-AlP monolayer. Thus, these results indicate that the V-AlP monolayer will have promising applications in nanoelectric devices.

Effects of stacking method and strain on the electronic properties of the few-layer group-IVA monochalcogenide heterojunctions.

Group-IV monochalcogenides (GeSe, SnSe, GeS, SnS) are a class of promising monolayer materials for nanoelectronic applications. However, the GeSe monolayer is the only direct semiconductor in the group-IV monochalcogenides, which limits their application in nanoelectronic fields. Stacking is usually a good strategy to design two-dimensional (2D) materials with novel properties. Taking these monolayer monochalcogenides as basic building blocks, various van der Waals (vdW) heterojunctions can be constructed by different stacking methods. In this study, we systematically investigated the structures, stabilities and electronic properties of thirty-six few-layer group-IV monochalcogenide heterojunctions. All the vdW heterojunctions are proved to be stable. The degree of stability of the few-layer heterojunctions is found to increase with the number of layers. The band gap values of heterojunctions are dependent not only on the components, but also on the stacking order. Five novel 2D direct semiconductors (SnSe/GeSe, GeS/SnS, SnSe/GeSe/SnSe, SnS/GeSe/SnSe and SnS/GeSe/SnSe) are obtained. It's found that biaxial strain can not only tune the values of band gap, but also change the type of the 2D materials. The band gaps of the heterojunctions monotonically increase with the increasing strain and most few-layer heterojunctions transform between direct and indirect semiconductors under biaxial strain. Five heterojunctions (SnSe/GeSe, GeS/SnS, GeSe/SnSe/SnS, SnS/GeSe/SnSe and GeSe/SnS/GeS/SnSe) are found to remain as direct semiconductors under tensile strain (0-0.1). Since the band gaps of these heterojunctions are easy to control in a suitable range, they may have potential applications in nanoelectronic fields.

Toll-like receptor 2 -196 to -174 del polymorphism influences the susceptibility of Han Chinese people to Alzheimer's disease.

BACKGROUND: Toll-like receptor 2 (TLR2) represents a reasonable functional and positional candidate gene for Alzheimer's disease (AD) as it is located under the linkage region of AD on chromosome 4q, and functionally is involved in the microglia-mediated inflammatory response and amyloid-ß clearance. The -196 to -174 del polymorphism affects the TLR2 gene and alters its promoter activity. METHODS: We recruited 800 unrelated Northern Han Chinese individuals comprising 400 late-onset AD (LOAD) patients and 400 healthy controls matched for gender and age. The -196 to -174 del polymorphism in the TLR2 gene was genotyped using the polymerase chain reaction (PCR) method. RESULTS: There were significant differences in genotype (P = 0.026) and allele (P = 0.009) frequencies of the -196 to -174 del polymorphism between LOAD patients and controls. The del allele was associated with an increased risk of LOAD (OR = 1.31, 95% CI = 1.07-1.60, Power = 84.9%). When these data were stratified by apolipoprotein E (ApoE) ε4 status, the observed association was confined to ApoE ε4 non-carriers. Logistic regression analysis suggested an association of LOAD with the polymorphism in a recessive model (OR = 1.64, 95% CI = 1.13-2.39, Bonferroni corrected P = 0.03). CONCLUSIONS: Our data suggest that the -196 to -174 del/del genotype of TLR2 may increase risk of LOAD in a Northern Han Chinese population.

Genetic association of rs11610206 SNP on chromosome 12q13 with late-onset Alzheimer's disease in a Han Chinese population.

BACKGROUND: Several genome wide screens and candidate gene studies have implicated the chromosome 12p13 locus as possibly harboring genetic variants predisposed to late-onset Alzheimer's disease (LOAD). Recently, the strongest significant association was reported for the single nucleotide polymorphism (SNP) rs11610206 on chromosome 12q13 in an independent genome-wide association study (GWAS) in Caucasians. METHODS: We investigated whether the SNP on chromosome 12q13 was associated with LOAD in a Han Chinese population. The common rs11610206 SNP on chromosome 12q13 was genotyped using MALDI-TOF mass spectrometry in 322 patients with LOAD and in 391 healthy controls matched for sex and age. RESULTS: Patients with LOAD had higher frequencies of T allele (56.0% versus 49.2%) compared with controls [odds ratio (OR)=1.45, 95% confidence intervals (CI)=1.08-1.95, and P=0.01]. After stratification by APOE ε4-carrying status, the T allele of rs11610206 was significantly associated with LOAD only in APOE ε4 allele carriers (OR=2.05, 95% CI=1.21-3.47, and P=0.007). Furthermore, multivariate logistic regression analysis showed that the TT genotype carriers demonstrated a 1.52-fold risk when compared with (TC+CC) genotype carriers (OR=1.52, 95% CI=1.07-2.17, and P=0.02). CONCLUSIONS: This study demonstrates an association of rs11610206 polymorphism locus on chromosome 12q13 with risk for LOAD in Han Chinese.