Graphene-like two-dimensional ionic boron with double dirac cones at ambient condition

Recently, partially ionic boron (γ-B28) has been predicted and observed in pure boron, in bulk phase and controlled by pressure [Nature, 457 (2009) 863]. By using ab initio evolutionary structure search, we report the prediction of ionic boron at a reduced dimension and ambient pressure, namely, the two-dimensional (2D) ionic boron. This 2D boron structure consists of graphene-like plane and B2 atom pairs, with the P6/mmm space group and 6 atoms in the unit cell, and has lower energy than the previously reported α-sheet structure and its analogues. Its dynamical and thermal stability are confirmed by the phonon-spectrum and ab initio molecular dynamics simulation. In addition, this phase exhibits double Dirac cones with massless Dirac fermions due to the significant charge transfer between the graphene-like plane and B2 pair that enhances the energetic stability of the P6/mmm boron. A Fermi velocity (vf) as high as 2.3 x 106 m/s, which is even higher than that of graphene (0.82 x 106 m/s), is predicted for the P6/mmm boron. The present work is the first report of the 2D ionic boron at atmospheric pressure. The unique electronic structure renders the 2D ionic boron a promising 2D material for applications in nanoelectronics.

“Well this is it. Just get on with it”: Pain willingness and activity engagement in people with chronic pain

Pain is recognised as a problem of significant concern worldwide and in the latest Global Burden of Disease Study, low back pain was identified as the biggest contributor worldwide to Years Lived with Disability. There is evidence to suggest that people who accept their chronic pain have a higher quality of life, lower levels of disability and distress, and function better emotionally, socially and physically. Findings on the specific pathways linking pain acceptance to quality of life outcomes are less clear. the two widely accepted pain acceptance factors, pain willingness and activity engagement, have not been well explored in qualitative studies on acceptance of chronic pain. To address this deficit in the literature, the current study has two related aims: 1) to explore pain willingness and activity engagement in the lives of people with chronic pain, and ; 2) to find out what people believe helps them to successfully get on with life in spite of chronic pain.