The host-guest inclusion strategy has potential to surpass the limitations of energy density and suboptimal performances of single explosives. The guest molecules can not only enhance the detonation performance of host explosives but can also enhance their stability. Therefore, the deeply analysis the role of guest influence on the pyrolysis decomposition of the host-guest explosive is necessary. The whole decomposition reaction stage of CL-20/H2O, CL-20/CO2, CL-20/N2O, CL-20/NH2OH was calculated by ReaxFF-MD. The incorporation of CO2, N2O and NH2OH significantly increase the energy levels of CL-20. However, different guest has little influence on the initial decomposition paths of CL-20. The Ea1 and Ea2 values of CL-20/CO2, CL-20/N2O, CL-20/NH2OH systems are higher than the CL-20/H2O system. Clearly, incorporation of CO2, N2O, NH2OH can inhibit the initial decomposition and intermediate decomposition stage of CL-20/H2O. Guest molecules get heavily involved in the reaction and influence on the reaction rate. k1 of CL-20/N2O and CL-20/NH2OH systems are significantly larger than that of CL-20/H2O at high temperatures. k1 of CL-20/CO2 system is much complex, which can be affected deeply by temperatures. k2 of CL-20/CO2, CL-20/N2O system is significantly smaller than that of CL-20/H2O at high temperatures. k2 of CL-20/NH2OH system is little difference at high temperatures. For the CL-20/CO2 system, the k3 value of CO2 is slight higher than that for CL-20/H2O, CL-20/N2O, CL-20/NH2OH systems, while the k3 values of N2 and H2O are slight smaller than that for CL-20/H2O, CL-20/N2O, CL-20/NH2OH systems. For the CL-20/N2O system, the k3 value of CO2 is slight smaller than that for CL-20/H2O, CL-20/CO2, CL-20/NH2OH systems. For the CL-20/NH2OH system, the k3 value of H2O is slight larger than that for CL-20/H2O, CL-20/CO2, CL-20/N2O systems. These mechanisms revealed that CO2, N2O and NH2OH molecules inhibit the early stages of the initial decomposition of CL-20, and play an important role for the decomposition subsequently.

Heat stress is a serious threat to tomato production. The ultrastructure and element mapping of tomato chloroplast were investigated under different nitrogen levels to explore the regulatory effect of nitrogen on tomato chloroplast under heat stress. Experiments design two temperature treatments (25°C/15°C, as control, 40°C/30°C, as severe high-temperature, SHT ) and four nitrogen levels (0.0 kg hm-2, N1; 187.5 kg hm-2, N2; 250 kg hm-2, N3, as recommended nitrogen-application; 312.5kg hm-2 , N4) for a duration of 5 days in artificial climate chamber. The results showed that heat stress led to obvious damage to the ultrastructure of tomato chloroplast, including thylakoid stacking disorder, granum destruction, and starch grain aggregation and degradation. With the increase of nitrogen level, the ratio of long and short axes of tomato chloroplasts increased, the differentiation of chloroplasts was strengthened, the number of plastoglobuli was increased and aggregated, and the degree of damage to the ultrastructure of chloroplasts was reduced. The regulatory effect of nitrogen on the ultrastructure of tomato chloroplasts under heat stress was mainly reflected in the phosphorylation degradation process of starch granules in chloroplasts. There are obvious segmentation lines of Ca, P and Cl on both sides of the inner and outer chloroplasts, and enriched in the chloroplasts, which can outline the boundary of the chloroplasts. Element mapping analysis revealed that heat stress significantly increased the contents of calcium, phosphorus and chlorine in the chloroplast of tomato leaves, while the contents of potassium was decreased. The application of nitrogen fertilizer could significantly regulate the element distribution of tomato chloroplast under heat stress, especially the regulation of phosphorus, chlorine, calcium, magnesium. These results provide new insight into the role of nitrogen using TEM-EDX mapping in the protection of tomato chloroplast under heat stress and the mechanism of heat stress tolerance in plants.

Peach (L.) is a kind of fruit tree with considerable economic and nutritional significance. However, it shows a high sensitivity to drought stress, which has a profound impact on its growth. L-methionine (MET) and L-proline (PRO) are two amino acids synthesized by plants, which play an important role in abiotic stress response. However, their exact mechanism of action remains elusive. Through physiological analysis, MET (500ppm) and PRO (500ppm) treatments can effectively reduce the adverse effects of drought stress on the growth of peach seedlings. The results show that MET and PRO can effectively inhibit the stomatal opening of plant leaves under drought conditions and reduce the water evaporation of leaves under drought conditions. In addition, the application of MET or PRO promoted the accumulation of carbohydrates in the leaf tissues of peach seedlings under drought conditions, increased the intracellular relative water content (24%, 24%), decreased the leaf electrical conductivity (21%, 24%), and alleviated the membrane damage caused by drought. Experimental studies have confirmed that the alleviation of drought stress is due to the removal of reactive oxygen species (ROS) in vivo, that is, the downregulation of malondialdehyde (18%, 19%)，peroxidase (50%, 5%) and superoxide dismutase (12%, 14%) activities. In addition, the application of exogenous amino acids also improved the root morphological structure and root vitality of peach seedlings，which was conducive to absorbing external buffer substances and alleviating drought stress. In summary, the application of exogenous amino acids can effectively alleviate the effects of drought stress on plants and reduce the harm.

Pulmonary artery stenosis represents a group of disorders involving main, branch or peripheral pulmonary arteries resulting either in pain, dyspnea, hemoptysis or even no symptoms. Early diagnosis and timely intervention are crucial for reducing mortality, while timely diagnosis is challenging due to the nonspecific symptoms. Computed tomography pulmonary angiography (CTPA) is useful in the diagnosis because it can provide more details about the abnormal changes in the lumen, vessel wall and adjacent mediastinal structures. Congenital and acquired pulmonary artery anomalies have some characteristics on CTPA, which can be useful for differential diagnosis. Awareness of these conditions and is important for the radiologists. This pictorial review provides an overview of CTPA imaging features of pulmonary artery stenosis.