RESUMO
In recent years group III nitrides have gained recognition as being the most important materials for optoelectronics and electronics applications. The zinc-blende modification of GaN and AlN is receiving much attention over their wurtzite structure. Our present work deals with the detailed ab initio calculations of group III nitrides and phosphides in the zinc-blende phase. The plane wave pseudopotential approach is used to study the different properties of the material based on the concept of density functional theory (DFT). The converged plane wave cut-off energy (E(cut)) is used to set the number of plane waves, which varies from material to material. The calculated energy bandgaps are based on our theoretical equilibrium lattice constants. Our reported energy bandgap for InN (0.86 eV) is in good agreement with the recently reported experimental result (>0.7 eV and<1.0 eV).
RESUMO
Transglutaminase-2 (TGM-2) stabilizes extracellular matrix (ECM) proteins by cross-linking and has been implicated in several fibrotic disorders. Arecoline present in betel quid has been proposed as one of the causative factors for oral submucous fibrosis (OSMF). Hence, we hypothesize that arecoline may regulate TGM-2 and may have a role in the pathogenesis of OSMF. The expression of TGM-2 was studied in OSMF tissues by real-time RT-PCR analysis, and significant overexpression was observed in most OSMF tissues (P=0.0112) compared with normal tissues. Arecoline induced TGM-2 mRNA and protein expression as well as TGM-2 activity in human gingival fibroblast cells. The addition of methocramine hemihydrate (M-2 muscarinic acetylcholine receptor selective antagonist) or 8'-bromo-cAMP abolished arecoline-mediated TGM-2 induction, suggesting a role for M-2 muscarinic acid receptor and a repressor role for cAMP. Our study provides evidence for TGM-2 overexpression in OSMF and its regulation by arecoline in oral fibroblasts.