Electron Delocalization in Gate-Tunable Gapless Silicene

The application of a perpendicular electric field can drive silicene into a gapless state, characterized by two nearly fully spin-polarized Dirac cones owing to both relatively large spin-orbital interactions and inversion symmetry breaking. Here we argue that since inter-valley scattering from non-magnetic impurities is highly suppressed by time reversal symmetry, the physics should be effectively single-Dirac-cone like. Through numerical calculations, we demonstrate that there is no significant backscattering from a single impurity that is non-magnetic and unit-cell uniform, indicating a stable delocalized state. This conjecture is then further confirmed from a scaling of conductance for disordered systems using the same type of impurities.Comment: 6 pages, 3 figures, published versio

Enhanced Steroid Metabolites Production by Resting Cell Phytosterol Bioconversion

The steroid metabolites 9-hydroxy-androstenedione (9-OH-AD), androstadienedione (ADD) and androstenedione (AD) are important steroidal pharmaceuticals. In order to raise the production of steroid metabolites, an efficient resting cell phytosterol bioconversion process was developed to produce 9-OH-AD in the presence of hydroxypropyl-β-cyclodextrin (HP-β-CD). Cell growth medium containing phytosterol as an inducer positively improved cell activity. Under aerobic conditions, bioconversion proceeded at 70 g L–1 phytosterol in the presence of HP-β-CD (the optimized molar ratio of HP-β-CD/phytosterol was 1:1) with 30 g L–1 resting Mycobacterium neoaurum NwIB-yV cells (cell dry mass) in a 5-L bioreactor, where 9-OH-AD production and space-time yield reached 36.4 g L–1 and 9.1 g L–1 d–1, respectively. The recycling of cells and HP-β-CD enables cost-saving and industrial applications. This bioprocess was also applied for the production of ADD and AD. The production of these steroid metabolites was much higher than that reported in previous studies

Impact of periodontal conditions on the quality of life of pregnant women: a cross-sectional study

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