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[Display omitted] • The stability of metal atoms on the boron vacancy (BV) is higher than nitrogen vacancy (NV). • The interaction energy of M@NV with O 2 is higher than that of M@BV systems. • While NV acts as electron donor, BV acts as electron acceptor. • The highest O O bond stretching is found for Cu@NV. • Spontaneous CO oxidation has been demonstrated by the Cu@NV system. The stability of isolated metal atom on a support plays very crucial role to avoid ensemble effects of agglomeration and clustering. Defects in support matrix provide additional binding to enhance the stability of single atom catalyst. Here, using plane wave based pseudo-potential approach, we report the activation of oxygen molecule by Co, Ni and Cu embedded h-BN sheet with both B and N vacancy. We have used O O bond stretching as probe for the activation. The results show that the stability of these metal atoms is higher at the vacancy site than on pristine h-BN. The atomic charge distribution of the metal embedded h-BN sheet suggests that while for boron vacancy defects metal atoms donate electronic charge, for nitrogen vacancy defects metal atoms accept electronic charge from the sheet. The chemical reactivity of the M doped h-BN sheet has been analyzed through electronic density of states spectrum. The interaction of O 2 molecule with metal supported h-BN sheet suggests that the interaction energy as well as the O O bond stretching is higher on metal atom at the nitrogen defected site. A case study of CO oxidation on the Cu embedded NV sheet has been demonstrated by co-adsorption of CO and O 2 molecules. [ABSTRACT FROM AUTHOR]

Theoretical computations conducted to understand the geometric and electronic features of the 4-nitro-2,5-bis(4-mercaptophenylethynyl)phenlyamine molecule are presented. The electronic transport pattern in this molecule is analyzed from the electronic structure and spatial orientations of the molecular orbitals.

Purpose: To compare the measurement of AC/A ratios while using the gradient method with plus or minus lenses at a fixed near point Method: A convenience sampling method of 30 Malaysians aged 13 to 30 years was used in this study. Relevant demographic and clinical data were obtained. The measurement of the near phoria was performed with a Maddox wing using both plus and minus lenses. The AC/A ratios with ±3.00 diopter (D) lenses were compared. The data were analyzed using the Wilcoxon Signed Rank test to investigate the changes in AC/A ratio while using plus and minus lenses. Result: The mean age of the subjects was 23.46±5.09 years. The mean AC/A ratios with plus lenses and minus lenses were 2.14±0.85 and 1.53±0.71, respectively. The AC/A ratio measured via the gradient method was significantly different (p=0.002). However, the association of AC/A ratio and phoria among gender and age groups was not significant (p>0.05). Conclusion: This study shows that the gradient AC/A ratio with a +3D lens is significantly different from a -3D lens. Clinically, we should use both plus and minus lenses while measuring the AC/A ratio with the gradient method rather than a single lens type. [ABSTRACT FROM AUTHOR]

The realization of a molecular device with a unimolecular rectifying function is one of the most important requirements in nanotechnology. In the present study, the geometric and electronic structure of the alkyl derivative molecule C37H50N4O4 has been investigated theoretically using ab initio quantum mechanical calculations. This molecule has a donor–spacer–acceptor structure, and is a leading candidate for the creation of a molecular rectifying device. The results suggest that in donor–acceptor molecular complexes such as this, while the lowest unoccupied orbital is concentrated around the acceptor sub-unit, the highest occupied molecular orbital is localized on the donor sub-unit. The approximate potential differences for an optimized PNX molecule have been estimated to be 2.683 eV at the B3LYP/6-311g++(d,p) level of theory. [Copyright &y& Elsevier]