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Although alcohol is associated with higher upper aerodigestive tract ( UADT) cancer risk, only a small fraction of alcoholics develop cancers. There is a lack of evidence proving the association of tag single nucleotide polymorphisms of alcohol-metabolizing enzymes with cancer risk. The aim of this study was to determine the association of these genetic polymorphisms with UADT cancer risk in a Chinese population. It was a hospital-based case-control candidate gene study. The databases of the International Hap Map Project were searched for haplotype tag single nucleotide polymorphisms of the genes alcohol dehydrogenase ( ADH)1 B, ADH1C, and aldehyde dehydrogenase ( ALDH)2. The genotyping was performed by the Sequenom MassARRAY system. Totally, 120 head and neck squamous cell carcinoma, 138 esophageal squamous cell carcinoma patients, and 276 age- and gender-matched subjects were enrolled between June 2008 and June 2010.Minor alleles of ADH1B (rs1229984) and ALDH2(rs671) were not only associated with the risk of UADT cancers (odds ratio [ OR] [95% confidence interval, CI]: 3.53 [2.14-5.80] and 2.59 [1.79-3.75], respectively) but also potentiated the carcinogenic effects of alcohol ( OR [95% CI]: 53.44 [25.21-113.29] and 70.08 [33.65-145.95], respectively). Similar effects were observed for head/neck and esophageal cancer subgroups. Multivariate logistic regression analysis identified four significant risk factors, including habitual use of cigarettes, alcohol, betel quid, and lower body mass index ( P < 0.001). The haplotypes GAGC ( OR 1.61, 95% CI 1.08-2.40, P = 0.018) and CCAATG ( OR 1.69, 95% CI 1.24-2.30, P < 0.001) on chromosomes 4 and 12, respectively, were associated with higher cancer risk. These findings suggested that risk allele or haplotype carriers who consume alcohol and other carcinogens should be advised to undergo endoscopy screening. The information can be used to determine the degree of susceptibility of each subject and can be combined with other environmental factors, like carcinogen consumption, in the screening analysis. [ABSTRACT FROM AUTHOR]

The evolution of the structural and electronic properties from sheet to silicene is studied by using first-principles density functional theory. It is found that the planar configurations of the - monolayer systems are basically kept except for the increase of the buckling of the planar structure when the substitution ratio of Si increases. Band gaps of the - monolayer system decrease gradually when the substitution ratio of Si atoms ranges from 0% to 100%. The energy and type of the band gaps are closely related with the substitution ratio of Si atoms and the - order. Further analysis of density of states reveals the orbital contribution of and atoms near the Fermi level. The discussion of the electronic evolution from SiC sheet to silicene would widen the application of the - monolayer systems in the optoelectronic field in the future nanotechnology. [ABSTRACT FROM AUTHOR]

In this paper, we studied the structural and electronic properties of core/shell nanocables composed of cubic silicon carbide nanowires (β-) and boron nitride nanotubes (BNNT) using first-principles pseudopotential plane wave method within density functional theory. Our results show that the β-/BNNT heterojunction structures are metallic, which primarily originates from the contributions of the BNNTs and the surfaces of s. The BNNTs exhibit metallic characters after the nanowires are inserted. The transition of the BNNTs is attributed to the charge transfer between BNNTs and s. [ABSTRACT FROM AUTHOR]

The platinum copper alloy nanocrystals(NCs) have generated muchinterest because of their wide applications in fuel cells due primarilyto their good catalytic performance and to decreasing sensitivitytoward CO poisoning. The exact atomic-level morphology of platinumcopper alloy NCs is still not clear in the literature, and researchto understanding the poisoning mechanism is still insufficient todate. In this article, we report on density functional calculationsof small PtnCu clusters and their adsorptionof a CO molecule that provide evidence for degrading adsorption ofthe CO molecule compared to pure platinum clusters. The lowest-energygeometries of PtnCu and PtnCuCO clusters have been identified. The CO moleculeprefers to be adsorbed on the nearest platinum atom by the C-end-onmode, forming linear or quasi-linear O–C–Pt structures.The adsorption energies indicate that the introduction of a copperatom decreases the adsorption ability of the CO molecule. The localdensity of states of the representative clusters is used to characterizethe adsorption properties of the CO molecule on the PtnCu clusters. Results from our theoretical calculationscan be helpful for understanding the poisoning mechanism of the COmolecule on the platinum copper alloy NCs. [ABSTRACT FROM AUTHOR]