Structure and chemical state of oxide films formed on crystalline TiNi alloy and glassy Ti-Ni-Ta-Si surface alloy

The stable oxide layers formed by chemical or electron-beam treatments of TiNi shape memory alloys are able to provide a good corrosion resistance and prevent release of toxic Ni. The mechanisms responsible for corrosion behavior of Ti-bearing alloys are currently not completely clear. In this work, the structure and electrochemical properties of surface oxides on TiNi alloy and Ti-Ni-Ta-Si surface alloy were examined. The glassy structure of the surface alloy was produced by a liquid phase mixing of Ti60Ta30Si10 (at.%) film with a TiNi substrate using a low-energy high-current electron beam. The reference electropolished TiNi alloy and the Ti-Ni-Ta-Si surface alloy exhibit thin (2-4 nm) glassy-crystalline oxide layers varying by chemistry and phase composition as confirmed using high-resolution transmission electron microscopy and x-ray photoelectron spectroscopy. It is shown that during anodic polarization in 0.9% NaCl and Lock-Ringer solutions, the oxide layer on the Ti-Ni-Ta-Si surface alloy possesses an enhanced passivation ability compared to the reference sample. We have revealed that the absence of oxidation species Ni2+ and the lower nickel concentration in the subsurface layer are closely related with corrosion resistance. A scheme describing the formation of corrosion products via transport of nickel ions through the free volumes (interstitial spaces, interfaces between clusters/particles) inside the oxide layer was proposed

A Genome-Wide Association Study Reveals a BDNF-Centered Molecular Network Associated with Alcohol Dependence and Related Clinical Measures

At least 50% of factors predisposing to alcohol dependence (AD) are genetic and women affected with this disorder present with more psychiatric comorbidities, probably indicating different genetic factors involved. We aimed to run a genome-wide association study (GWAS) followed by a bioinformatic functional annotation of associated genomic regions in patients with AD and eight related clinical measures. A genome-wide significant association of rs220677 with AD (p-value = 1.33 × 10−8 calculated with the Yates-corrected χ2 test under the assumption of dominant inheritance) was discovered in female patients. Associations of AD and related clinical measures with seven other single nucleotide polymorphisms listed in previous GWASs of psychiatric and addiction traits were differently replicated in male and female patients. The bioinformatic analysis showed that regulatory elements in the eight associated linkage disequilibrium blocks define the expression of 80 protein-coding genes. Nearly 68% of these and of 120 previously published coding genes associated with alcohol phenotypes directly interact in a single network, where BDNF is the most significant hub gene. This study indicates that several genes behind the pathogenesis of AD are different in male and female patients, but implicated molecular mechanisms are functionally connected. The study also reveals a central role of BDNF in the pathogenesis of AD

A DFT Study of Direct Oxidation of Benzene to Phenol by N 2

Density functional theory (DFT) calculations were carried out in a study of the mechanism of benzene oxidation by N2O to phenol over an extra framework dimeric [FeOFe]2+ species in ZSM-5 zeolite represented by a [Si6Al2O9H14(Fe(µ-O)Fe)] cluster model. The catalytic reactivity of such a binuclear species is compared with that of mononuclear Fe2+ and (FeO)+ sites in ZSM-5 investigated in our earlier works at the same level of theory (J. Phys. Chem. C2009, 113, 15307; 2010, 114, 12580). The activation energies for the elementary reaction step involved in the benzene hydroxylation over the binuclear and the mononuclear iron sites are comparable. The major difference in the catalytic behavior of the systems considered is related to the ability of Fe3+-containing sites to promote side reactions leading to the active site deactivation. Regeneration of the active site via the phenol desorption is much less favorable than its dissociation resulting in the formation of very stable grafted phenolate species on both the [Fe(µ-O)Fe]2+ and (FeO)+ sites. In the case of Fe2+ sites such an alternative reaction path does not exist resulting in their stable catalytic performance. Benzene hydroxylation and phenol formation over the binuclear (Fe(µ-O)Fe)2+ sites in ZSM-5 are promoted in the presence of water. These computational findings are consistent with the experimental observations and allow their rationalization at the molecular level