A large gap opening of graphene induced by the adsorption of CO on the Al-doped site

We investigated CO adsorption on the pristine, Stone-Wales (SW) defected, Al- and Si- doped graphenes by using density functional calculations in terms of geometric, energetic and electronic properties. It was found that CO molecule is weakly adsorbed on the pristine and SW defected graphenes and their electronic properties were slightly changed. The Al- and Si- doped graphenes show high reactivity toward CO, so calculated adoption energies are about ?11.40 and ?13.75 kcal mol^?1 in the most favorable states. It was found that, among all the structures, the electronic properties of Al-doped graphene are strongly sensitive to the presence of CO molecule. We demonstrate the existence of a large E_g opening of 0.87 eV in graphene which is induced by Al-doping and CO adsorption.     

Arsenic interactions with a fullerene-like BN cage in the vacuum and aqueous phase

Adsorption of arsenic ions, As (III and V), on the surface of fullerene-like B₁₂N₁₂ cage has been explored in vacuum and aqueous phase using density functional theory in terms of Gibbs free energies, enthalpies, geometry, and density of state analysis. It was found that these ions can be strongly chemisorbed on the surface of the cluster in both vacuum and aqueous phase, resulting in significant changes in its electronic properties so that the cluster transforms from a semi-insulator to a semiconductor. The solvent significantly affects the geometry parameters and electronic properties of the As/B₁₂N₁₂ complexes and the interaction between components is considerably weaker in the aqueous phase than that in the vacuum.     

Improved microspore embryogenesis induction and plantlet regeneration using putrescine,cefotaxime and vancomycin in Brassica napus L.

The effects of three periods of exposure (12, 24 and 48 h) to different levels of putrescine (0, 0.2, 0.5, 1.0, 2.0 and 5.0 mg l^?1), as well as three incubation periods (24, 48 and 72 h) to different levels of cefotaxime and vancomycin (0, 50, 100, 200 and 500 mg l^?1) on microspore embryogenesis of rapeseed cv. ‘Hyola 401’ were assessed. Microspore embryogenesis was enhanced about threefold compared with untreated culture following 48 h treatment with 0.2 mg l^?1 putrescine. Putrescine treatment at 0.5 mg l^?1 for 48 h effectively induced root formation and increased normal plantlet regeneration by 92 % when microspore-derived embryos (MDEs) were transferred to regeneration medium. The highest embryo yield (184.2 embryos Petri dish^?1) was possible when induction medium was supplemented with 50 mg l^?1 cefotaxime for 24 h and the highest normal regeneration was observed in cultures exposed to 50 and 100 mg l^?1 at all durations tested. More abnormal MDEs (76 and 82 %) were observed when microspores treated with 200 and 500 mg l^?1 cefotaxime many of which failed to regenerate normally and resulted in callusing. Vancomycin at 100 mg l^?1 during the 48 h exposure increased the number of MDEs (181.6 embryos Petri dish^?1) in contrast to untreated cultures (93.6 embryos Petri dish^?1) but, normal plantlet regeneration decreased as vancomycin level increased and high callusing (84 and 90 %) was observed with 200 and 500 mg l^?1 for 72 h. Microspore embryogenesis and plant regeneration could be improved by putrescine, cefotaxime and vancomycin when appropriate levels and durations of incubation were selected.     

Enhanced Efficiency of In Vitro Rootstock Micro-propagation Using Silica-Based Nanoparticles and Plant Growth Regulators in Myrobalan 29C (Prunus cerasifera L.)

Different experiments were conducted to establish and optimize an efficient in vitro micropropagation protocol for Myrobalan 29C rootstocks. Disinfection of initial explants with AgNPs (2.5%) reduced the needed amount of NaClO (5.0%) by half. The highest rates of induced active buds were obtained in the DKW (90.63%), MS (86.67%), modified MS (82.22%), and WPM (78.15%) culture media supplemented with BAP (2.22 μmol L^?1)?+?GA₃ (2.88 μmol L^?1)?+?IBA (0.05 μmol L^?1)?+?Fe-EDDHA (228.72 μmol L^?1). The highest quality of the proliferated shoots (5.0) was also achieved using DKW medium. Inclusion of GA₃ (5.76 μmol L^?1), Fe-EDDHA (114.36–228.72 μmol L^?1), or BAP (2.22 μmol L^?1) were also able to enhance the rate of shoot multiplication. Compared to the agar-solidified culture system, the established shoots proliferated more efficiently when immersed by bioreactor in the liquid DKW culture medium on a regular basis. Exogenous application of silica-based nanoparticles (NPs) including the chemically synthesized silica NPs (TSiO₂ NPs, 1.0 ppm), rice husk derived biogenic silica NPs (RSiO₂ NPs, 10.0 ppm), or amine modified silica NPs (ASiO₂ NPs, 10.0 ppm) to the multiplication medium increased the number of regenerated lateral shoots by 520%, 360%, and 349%, respectively. Proliferated shoots with well-developed root system were obtained from the rooting medium supplemented with 19.68 μmol L^?1 IBA. Our results indicated that the rootstocks of Myrobalan 29C could be efficiently propagated under in vitro condition providing proper culture medium and optimal concentrations of additives and plant growth regulators were adopted.