No abstract

Background Rice is particularly effective, compared to other cereals, at accumulating arsenic (As), a nonthreshold, class 1 human carcinogen in shoot and grain. Nano-zinc oxide is gradually used in agricultural production due to its adsorption capacity and as a nutrient element. An experiment was performed to explore the effects of zinc oxide nanoparticles (nZnO) on arsenic (As) toxicity and bioaccumulation in rice. Rice seedlings were treated with different levels of nZnO (0, 10, 20, 50, 100 mg/L) and As (0, and 2 mg/L) for 7 days. Results The research showed that 2 mg/L of As treatment represented a stress condition, which was evidenced by phenotypic images, seedling dry weight, chlorophyll, and antioxidant enzyme activity of rice shoot. The addition of nZnO (10–100 mg/L) enhanced the growth and photosynthesis of rice seedlings. As concentrations in the shoots and roots were decreased by a maximum of 40.7 and 31.6% compared to the control, respectively. Arsenite [As (III)] was the main species in both roots (98.5–99.5%) and shoots (95.0–99.6%) when exposed to different treatments. Phytochelatins (PCs) content up-regulated in the roots induced more As (III)-PC to be complexed and reduced As (III) mobility for transport to shoots by nZnO addition. Conclusion The results confirmed that nZnO could improve rice growth and decrease As accumulation in shoots, and it performs best at a concentration of 100 mg/L.

Projectile fragmentation cross sections are calculated for reactions of 20 Ne on the C, Al, Cu, Sn and Pb targets at 400 A MeV by using the improved quantum molecular dynamics model together with the statistical model code GEMINI. The improved quantum molecular dynamics model is applied to describe the dynamical process, and the GEMINI model is used to simulate the de-excitation process of excited primary fragments. It is found that the total cross sections increase as a function of the target mass, which is in good agreement with the experimental results and other theoretical predictions. The odd-even effect of the partial cross sections observed in experiments is well reproduced, which appears in the de-excitation process of the excited primary fragments as a result of pairing effect and is mainly formed in the grazing collisions. The results of isospin distributions demonstrate that the odd-even effect of partial cross sections mainly comes from the fragments with T Z = 0, ±0.5.

No abstract

No abstract