High-Contrast Photoacoustic Imaging of Localized Cysteine in Orthotopic Breast Cancer Enabled by A Totally-Caged Methylene Blue Probe.

High-contrast photoacoustic sensing imaging (PASI) was greatly determined by optical absorption changes of the absorbers usually enabled by activatable probes via controllably converting the absorbed electromagnetic energy to ultrasound waves. However, most of current photoacoustic probes still suffer from limited imaging contrast towards specific species because of their small absorption spectral changes in the near infrared (NIR) region. Herein, we developed a methylene blue-based photoacoustic probe with its NIR optical absorption totally caged, which could afford dramatical "OFF-to-ON" absorption transition for high-contrast photoacoustic imaging towards the localized cysteine. The rationally designed methylene blue-based probe for cysteine (MB-Cys) would keep in off state with almost no absorption in NIR region, while upon activated by cysteine through cyclization reaction with acrylates, it would reconstruct the π-conjugation system to release the free methylene blue with strong absorption centered at 665 nm (>130-fold enhancement). The unique responsive behavior could enable the PASI for photoacoustic mapping the cysteine in orthotopic breast cancer in a high-contrast manner. Therefore, this work established an up-to-date strategy to originally eliminate the background photoacoustic signal for PASI to accurately monitor cysteine in vivo.

Strategy for the Preparation of ZnS/ZnO Composites Derived from Metal-Organic Frameworks toward Lithium Storage.

The synergistic effect between multicomponent electrode materials often makes them have better lithium storage performance than single-component electrode materials. Therefore, to enhance surface reaction kinetics and encourage electron transfer, using multicomponent anode materials is a useful tactic for achieving high lithium-ion battery performance. In this article, ZnS/ZnO composites were synthesized by solvothermal sulfidation and calcination, with the utilization of metal-organic frameworks acting as sacrificial templates. From the point of material design, both ZnS and ZnO have high theoretical specific capacities, and the synergistic effect of ZnS and ZnO can promote charge transport. From the perspective of electrode engineering, the loose porous carbon skeleton that results from the calcination of metal-organic frameworks can enhance composite material conductivity as well as full electrolyte penetration and the area of contact between the electrolyte and active material, all of which are beneficial to enhancing lithium storage performance. As expected, ZnS/ZnO anode materials displayed remarkably high specific capacities and outstanding performance at different rates. Combining material design and electrode engineering, this paper provides another idea for preparing anode materials with excellent lithium storage properties.

Engineering at Subatomic Scale: Achieving Selective Catalytic Pathways via Tuning of the Oxidation States in Functionalized Single-Atom Quantum Catalysts.

Regulating the catalytic pathways of single-atom sites in single atom catalysts (SACs) is an exciting debate at the moment, which has redirected the research towards understanding and modifying the single-atom catalytic sites through various strategies including altering the coordination environment of single atom for desirable outcomes as well as increasing their number. One useful aspect concerning the tunability of the catalytic pathways of SACs, which has been overlooked, is the oxidation state dynamics of the single atoms. In this study, iron single-atoms (FeSA) with variable oxidation states, dependent on the precursors, are harnessed inside a nitrogen-rich functionalized carbon quantum dots (CQDs) matrix via a facile one-step and low-temperature synthesis process. Dynamic electronic properties are imparted to the FeSAs by the simpler carbon dots matrix of CQDs in order to achieve the desired catalytic pathways of reactive oxygen species (ROS) generation in different environments, which are explored experimentally and theoretically for an in-depth understanding of the redox chemistry that drives the alternative catalytic pathways in FeSA@CQDs. These alternative and oxidation state-dependent catalytic pathways are employed for specific as well as cascade-like activities simulating natural enzymes as well as biomarkers for the detection of cancerous cells.

Two complete mitochondrial genomes in Scolopendra and a comparative analysis of tRNA rearrangements in centipedes.

BACKGROUND: Centipedes are one of the oldest terrestrial arthropods belonging to the sub phylum Myriapoda. With the expansion of our understanding of the application of the two centipedes Scolopendra morsitans and Scolopendra hainanum, belonging to the order Scolopendromorpha, an exhaustive classification was required. Although consensus has been reached on the phylogeny of Chilopoda based on morphological traits, recent analyses based on molecular data exhibited differences in results. METHODS AND RESULTS: The mitochondrial genome sequences of S. morsitans and S. hainanum were obtained by next-generation sequencing. S. morsitans contains 13 PCGs, two rRNAs, 11 tRNAs, and one CR. whereas S. hainanum contains 12 PCGs, of which ATP8 remains unpredicted, two rRNAs, 14 tRNAs, and one CR. An obvious tRNA rearrangement was found in the genus Scolopendra. S. morsitans exhibited a loss of trnW, trnC, trnI, trnK, trnD, trnA, trnN, trnQ, trnF, trnT, trnS, trnL, and trnV, and a repeat of trnR and trnL. S. hainanum exhibited a loss of trnQ, trnC, trnW, trnI, trnD, trnQ, trnP, and trnV. Phylogenetic analyses of centipedes based on 12 PCGs supported the sister relationship between the orders Geophilomorpha and Lithobiomorpha and a close relationship between Scolopendra dehaani and S. hainanum. CONCLUSIONS: The new mitogenomes determined in this study provide new genomic resources for gene rearrangements and contribute to the understanding of the evolution of gene rearrangement in Chilopoda.

Effectiveness and Safety of Intravenous Nicorandil Application in Patients With Acute Heart Failure With Low Baseline Blood Pressure.

AIM: To evaluate the effectiveness and safety of intravenous nicorandil application in patients with acute heart failure (AHF) with low baseline blood pressure (systolic blood pressure <110 mmHg). METHOD: This prospective, controlled, single-centre study randomised 147 patients with AHF with low baseline blood pressure (including both emergent admission and newly developed low blood pressure while in hospital) to one of the following two groups: (1) control group (conventional diuretics, positive inotropic agents, and related therapy according to the guidelines); and (2) intervention group (intravenous [IV] nicorandil application plus routine care). Dyspnoea severity, the ratio of E to e' (E/e'), the incidence of side effects and adverse events, N-terminal pro-brain natriuretic peptide (NT-proBNP) level, left ventricular ejection fraction (LVEF; left ventricular systolic function) before discharge, average length of hospitalisation, LVEF and soluble suppression of tumorigenicity-2 (sST2) at 3 months after discharge, incidence of major adverse cardiac and cerebrovascular events (MACCE) and readmission rate within 3 months were recorded and compared between the two groups. RESULTS: Compared to the control group, nicorandil relieved dyspnoea effectively and improved E/e' significantly; the level of NT-proBNP was lower, LVEF was higher before discharge, and average length of hospital stay was shorter in the intervention group. After 3 months, the LVEF was higher, sST2 was lower, and the readmission rate was lower in the intervention group; there was no statistically significant difference in MACCE. CONCLUSIONS: Patients with AHF with low baseline blood pressure could benefit from IV nicorandil application in the urgent phase, but the long-term profits remained to be confirmed.

Cytomembrane visualization using Stokes parameter confocal microscopy.

A new, to the best of our knowledge, method for Stokes vector imaging is proposed to achieve imaging and dynamic monitoring of a non-labeled cytomembrane. In this work, a polarization state vector is described by a Stokes vector and expressed in chrominance space. A physical quantity called polarization chromaticity value (PCV) corresponding to a Stokes vector is used as the imaging parameter to perform Stokes vector imaging. By using the PCV imaging technique, the Stokes vector can be expressed in three-dimensional real space rather than in a Poincare sphere. Furthermore, a four-way Stokes parameter confocal microscopy system is designed to measure four Stokes parameters simultaneously and obtain micro-imaging. Label-free living onion cell membranes and their plasmolysis process are selected as the representative micro-anisotropy experimental analysis. It is proved that PCV imaging can perform visualization of cytomembranes, and further, microscopic orientation is demonstrated. The prospect of universal measurement of anisotropy details for analysis and diagnosis is provided.

A Fast Deploying Monitoring and Real-Time Early Warning System for the Baige Landslide in Tibet, China.

Landslide early warning systems (EWSs) have been widely used to reduce disaster losses. The effectiveness of a landslide EWS depends highly on the prediction methods, and it is difficult to correctly predict landslides in a timely manner. In this paper, we propose a real-time prediction method to provide real-time early warning of landslides by combining the Kalman filtering (KF), fast Fourier transform (FFT), and support vector machine (SVM) methods. We also designed a fast deploying monitoring system (FDMS) to monitor the displacement of landslides for real-time prediction. The FDMS can be quickly deployed compared to the existing system. This system also has high robustness due to the usage of the ad-hoc technique. The principle of this method is to extract the precursory features of the landslide from the surface displacement data obtained by the FDMS and, then, to train the KF-FFT-SVM model to make a prediction based on these precursory features. We applied this fast monitoring and real-time early warning system to the Baige landslide, Tibet, China. The results showed that the KF-FFT-SVM model was able to provide real-time early warning for the Baige landslide with high accuracy.

Reactions between N-Heterocyclic Carbene and Lutetium-Metallofullerenes: High Regioselectivity Directed by Electronic Effect in Addition to Steric Hindrance.

The Lewis acid-base pairing reaction between strained N-heterocyclic carbene (NHC) and endohedral metallofullerenes (EMFs) is an efficient strategy to obtain stable derivatives in a highly regioselective manner. Herein, we report an in-depth study on the reactions between 3-dimesityl-1 H-imidazol-3-ium-2-ide (1) and three different EMFs, namely, Lu3N@ Ih(7)-C80, Lu2@ C3 v(8)-C82, and Lu2@ C2 v(9)-C82, respectively. Only one monoadduct is obtained for each EMF under certain conditions, demonstrating surprisingly high regioselectivity and exclusive formation of monoadducts. X-ray results of the derivatives of Lu3N@C80 reveal that an epoxide adduct (2a) with a specific [6,6,6]-carbon atom of the C80 cage singly bonded to the normal carbene center (C2) of the NHC is obtained under ambient condition, whereas a pure argon atmosphere gives 2b with an abnormal C5-bonding structure. In contrast, the derivatives of Lu2@C82 (3 and 4) are both normal C2-bonding [5,6,6]-adducts without oxygen addition, even though air is involved in the reaction. Our theoretical results confirm that the remarkably high regioselectivity and the quantitative formation of monoadducts are direct result from the distributions of molecular orbital and electrostatic potential on the cage surfaces in addition to the previously assumed steric hindrance between the fullerene cage and the NHC moiety.

Lu2@C2n (2n = 82, 84, 86): Crystallographic Evidence of Direct Lu-Lu Bonding between Two Divalent Lutetium Ions Inside Fullerene Cages.

Although most of the M2C2n-type metallofullerenes (EMFs) tend to form carbide cluster EMFs, we report herein that Lu-containing EMFs Lu2C2n (2n = 82, 84, 86) are actually dimetallofullerenes (di-EMFs), namely, Lu2@Cs(6)-C82, Lu2@C3v(8)-C82, Lu2@D2d(23)-C84, and Lu2@C2v(9)-C86. Unambiguous X-ray results demonstrate the formation of a Lu-Lu single bond between two lutetium ions which transfers four electrons in total to the fullerene cages, thus resulting in a formal divalent state for each Lu ion. Population analysis indicates that each Lu atom formally donates a 5d electron and a 6s electron to the cage with the remaining 6s electron shared with the other Lu atom to form a Lu-Lu single bond so that only four electrons are transferred to the fullerene cages with the formal divalent valence for each lutetium ion. Accordingly, we confirmed both experimentally and theoretically that the dominating formation of di-EMFs is thermodynamically very favorable for Lu2C2n isomers.

Correlation between genetic polymorphism of matrix metalloproteinase-9 in patients with coronary artery disease and cardiac remodeling.

OBJECTIVE: To explore the correlation between genetic polymorphism of matrix metalloproteinase-9 (MMP-9) in patients with coronary artery disease (CAD) and cardiac remodeling. METHODS: A total of 272 subjects who received coronary angiography in our hospital from July 2008 to September 2013 were selected, including 172 CAD patients (CAD group) and another 100 ones (control group). Both groups were subjected to MMP-9 and ultrasonic detections to determine vascular remodeling and atherosclerotic plaques. C1562G polymorphism of MMP-9 gene was detected, and correlation with vascular remodeling and atherosclerotic plaque was analyzed. RESULTS: Serum MMP-9 level of CAD group (330.87±50.39 ng/ml) was significantly higher than that of control group (134.87±34.02 ng/ml) (P<0.05). Compared with control group, CAD group had significantly higher intima-media thickness, and significantly lower systolic peak velocity, mean systolic velocity and end-diastolic velocity (P<0.05). Total area of stenotic blood vessels was 67.34±22.98 mm(2), while that of control blood vessels was 64.00±20.83 mm(2). G/G, G/C and C/C genotype frequencies of MMP-9 differed significantly in the two groups (P<0.05). G and C allele frequencies of CAD group (70.9% and 29.1%) were significantly different from those of control group (50.0% and 50.0%) (P<0.05). G/G, G/C and C/C genotypes were manifested as lipid-rich, fibrous and calcified or ulcerated plaques respectively. Total area of stenotic blood vessels of G/G genotype significantly exceeded those of G/C and C/C genotypes (P<0.05), whereas the latter two had no significant differences. CONCLUSION: CAD promoted 1562C-G transformation of MMP-9 gene into genetic polymorphism, thus facilitating arterial remodeling and increasing unstable atherosclerotic plaques.

Tailoring and understanding the lithium storage performance of triple-doped cobalt phosphide composites.

Cobalt phosphide (CoP) with high theoretical capacity as well as ceramic-like and metal-like properties is considered as a promising anode for lithium-ion batteries (LIBs). However, the large volume change and sluggish kinetic response limit its practical application. The optimization of composition, structural control and performance regulation of CoP electrodes can be achieved by the bottom-up assembly technique of metal-organic frameworks (MOFs). Due to the effective electronic regulation and lithiophilicity brought by the multiple heteroatoms doping and the synergistic effect of the unique structure derived from MOFs, the N, O, P triple-doped carbon and CoP composites (ZCP@NOP) exhibited excellent rate capability (554.61 mAh g-1 at 2 A g-1) and cycling stability (806.7 mAh g-1 after 500 cycles at 0.5 A g-1). The essence and evolution of lithium storage mechanism in CoP electrodes are also confirmed by the ex-situ techniques. The synergistic benefits of heteroatom co-doping carbon and cobalt phosphide, such as the decrease of the diffusion energy barrier of Li-ions and the optimization of electronic structures, are highlighted in theoretical calculations. In conclusion, new thoughts and ideas for the creation of future battery anode are provided by the combination of the N, O, P co-doping and the adaptable structural adjustment technique.

Cellular Scale Curvature in Bioceramic Scaffolds Enhanced Bone Regeneration by Regulating Skeletal Stem Cells and Vascularization.

Critical-sized segmental bone defects cannot heal spontaneously, leading to disability and significant increase in mortality. However, current treatments utilizing bone grafts face a variety of challenges from donor availability to poor osseointegration. Drugs such as growth factors increase cancer risk and are very costly. Here, a porous bioceramic scaffold that promotes bone regeneration via solely mechanobiological design is reported. Two types of scaffolds with high versus low pore curvatures are created using high-precision 3D printing technology to fabricate pore curvatures radius in the 100s of micrometers. While both are able to support bone formation, the high-curvature pores induce higher ectopic bone formation and increased vessel invasion. Scaffolds with high-curvature pores also promote faster regeneration of critical-sized segmental bone defects by activating mechanosensitive pathways. High-curvature pore recruits skeletal stem cells and type H vessels from both the periosteum and the marrow during the early phase of repair. High-curvature pores have increased survival of transplanted GFP-labeled skeletal stem cells (SSCs) and recruit more host SSCs. Taken together, the bioceramic scaffolds with defined micrometer-scale pore curvatures demonstrate a mechanobiological approach for orthopedic scaffold design.

Differential photoacoustic microscopy technique.

Photoacoustic microscopy (PAM), whose image quality largely depends on the optical absorption of samples, provides endogenous information for structural and functional imaging. However, PAM technology in general can not provide edge enhancement imaging for absorbing objects. Therefore, PAM and differential microscopy are integrated for the first time in a single technique to obtain an edge enhancement image. The resolution test target RTA-07 and red blood cells are used as samples to achieve the desired spatial differential photoacoustic imaging. The feasible biomedical application of edge enhancement from the improved differential PAM was demonstrated.

Bone cutting processes and removal behaviors in orthopedic surgery with an ultrasonic orthopedic scalpel.

Bone cutting is a common and important procedure in surgery. As a type of orthopedic instrument, ultrasonic orthopedic scalpels (UOSs) have been widely used due to their safety and convenience. Therefore, it is very important to have a deep understanding of the cutting process and the bone removal behavior of a UOS, to improve cutter design and complement the basic theory of the bone-cutting mechanism. However, few studies have focused on the characteristics of ultrasonic cutting. In this work, based on bone structure, the bone-cutting processes of a UOS were defined and the bone removal behavior in ultrasonic bone cutting was studied. In this study, it was believed that a direction of ultrasonic vibration different from that of the lamellar arrangement and collagen fibers would lead to different cutting characteristics. Based on this, the cutting modes were divided into four typical types. After examining and analyzing the crack propagation and chip formation of compact bone for the four cutting modes, the removal behaviors of ultrasonic bone cutting were defined. At the same time, the surface morphology indicated that there were significant differences in the surface damage for different cutting modes, which supported the idea that the bone removal behaviors were different for different modes. In addition, the force signals were analyzed and the results showed that there were differences in the cutting forces for different cutting modes. The static and dynamic components of the cutting forces were also analyzed. The study demonstrated the correlation between bone removal and the microscopic and submicroscopic structure of bone in ultrasonic cutting. These conclusions provided guidelines for analyzing bone tissue injuries caused by UOSs, improving the surgical process of bone cutting, optimizing the design of orthopedic instruments, and further complementing the basic theory of bone cutting.

Analyzing the Energy and Damage Constitutive of Cemented Backfill with Different Water Content under Dynamic Load.

The dynamic characteristics of the filling body are the key parameters for designing the filling ratio and evaluating the stability of an underground stope. The different environment (water-bearing state) of the filling body in the underground stope exerts a complex impact on the mechanical behavior of the filling body. Therefore, six groups of cemented filling body specimens with different states were formed and subjected to dynamic uniaxial impact tests. The effects of water content on the mechanical properties, fractal dimension, and deformation damage characteristics of the cemented backfill under dynamic load were analyzed in depth, and a dynamic damage constitutive model that considers water damage and the compaction stage was established. The results indicate the following: (1) Due to the change of the specimen from the dry state to the water saturation state, the dynamic compressive strength of the cemented filling body decreases from 5.03 Mpa to 1.79 Mpa; however, the ductility of the specimen generally increases, and the filling body specimens with different water contents mainly exhibit tensile failure. (2) There is a significant nonlinear relationship between the water content and the fractal dimension Db of the cemented backfill specimen, and the growth rate of the fractal dimension Db tends to slow down with the increase in the water content. (3) From the energy evolution perspective, the water content of the specimen exerts a significant effect on the elastic deformation and failure stage of the stress-strain curve, and the slope of the dissipated energy-strain curve decreases with the increase in water content. (4) Based on the Weibull distribution and damage theory, a statistical damage constitutive model of cemented backfill was established, and it was compared with the experimental curve to verify the rationality of the model. Therefore, the relationship between stress and damage and the strain curves is discussed, and it is inferred that the damage evolution curve of cemented backfill is a typical S-shaped curve that exhibits a stable development-rapid increase-tending to be gentle. This study can provide a theoretical reference for further understanding the dynamic behavior and stability of backfill under different water conditions.

Metal-organic-framework derived Zn-V-based oxide with charge storage mechanism as high-performance anode material to enhance lithium and sodium storage.

Transition metal oxides have been extensively studied due to their large theoretical capacities, but their practical application has been hampered by low electrical conductivity and dramatic volume fluctuation during cycling. In this work, we synthesized Zn3V2O8 material using Zn-V-MOF (metal-organic framework) as a sacrificial template to improve the electrochemical characteristics of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Unique dodecahedral structure, larger specific surface area and higher ability to mitigate volume changes, improve the electrochemical reaction active site while accelerating ion transport. Zn3V2O8 with 2-methylimidazole as a ligand demonstrated a discharge capacity of 1225.9 mAh/g in LIBs and 761.6 mAh/g in SIBs after 300 cycles at 0.2 C. Density functional theory (DFT) calculation illustrates the smaller diffusion barrier energy and higher specific capacity in LIBs that is ascribed to the fact that Li has a smaller size and hence its diffusion is easier. This study may lead to a path for the manufacturing of high-performance LIBs and SIBs.

Nanostructured conversion-type anode materials of metal-organic framework-derived spinel XMn2O4 (X = Zn, Co, Cu, Ni) to boost lithium storage.

Bimetallic spinel transition metal oxides play a major part in actualizing eco-friendly electrochemical energy storage systems (ESSs). However, structural precariousness and low electrochemical capacitance restrict their actual implementation in lithium-ion batteries (LIBs). To address these demerits, the sacrificial template approach has been considered as a prospective way to strengthen electrochemical stability and rate performance. Herein, metal-organic frameworks (MOFs) derived XMn2O4-BDC (H2BDC = 1,4-dicarboxybenzene, X = Zn, Co, Cu, Ni) are prepared by a hydrothermal approach in order to discover the effects of various metal cations on the electrochemical performance. Among them, ZnMn2O4-BDC displays best electrochemical properties (1321.5 mAh g-1 at the current density of 0.1 A g-1 after 300 cycles) and high efficiency with accelerated Li+ diffusivity. Density functional theory (DFT) calculations confirm the ZnMn2O4 possesses the weakest adsorption energy on Li+ with a minimized value of -0.92 eV. In comparison with other XMn2O4 through traditional fabrication method, MOF-derived XMn2O4-BDC possesses a higher number of Li+ transport channels and better electric conductivity. This tactic provides a feasible and effective method for preparing bimetallic transition metal oxides and enhances energy storage applications.

Photoacoustic microscopy achieved by microcavity synchronous parallel acquisition technique.

We report on a sub-cellular resolution photoacoustic microscopy (PAM) system that employs microcavity synchronous parallel acquisition technique for detecting the weak photoacoustic (PA) signal excited by a modulated continuous wave (CW) laser source. The gas microcavity transducer is developed based on the fact that the bulk modulus of the gas is far less than the solid and the change of the air-gas pressure is inversely proportional to the gas volume, making it extremely sensitive to the tiny PA pressure wave. Besides, considering PA wave expends in various directions, detecting PA signals from different position and adding them together can increase the detecting sensitivity and the signal to noise ratio(SNR), then we employs two microphone to acquire PA wave synchronously and parallelly. We show that the developed PAM system is capable of label-free imaging and differentiating of the hemoglobin distribution within single red blood cells under normal and anemia conditions.

Tentative investigation towards precision polishing of optical components with ultrasonically vibrating bound-abrasive pellets.

Ultrasonic vibration has been employed to improve the quality of machined surface in the grinding of brittle materials. In this report, we transplant the philosophy of ultrasonic vibration assisted grinding to chemo-mechanical bound-abrasive-pellet polishing in anticipation of the improvement in either surface roughness or material removal rate. The preliminary experimental results show that the ultrasonic vibration assisted chemo-mechanical pellet polishing can yield desired results that material removal rate can be significantly raised while surface roughness is not degraded. The experimental results also indicate different mechanisms between ultrasonic-vibration-assisted chemo-mechanical pellet polishing and conventional chemo-mechanical bound-abrasive polishing.

Inorganic Nitrogen-Containing Aerosol Deposition Caused "Excessive Photosynthesis" of Herbs, Resulting in Increased Nitrogen Demand.

The amount of atmospheric nitrogen-containing aerosols has increased dramatically due to the globally rising levels of nitrogen from fertilization and atmospheric deposition. Although the balance of carbon and nitrogen in plants is a crucial component of physiological and biochemical indexes and plays a key role in adaptive regulation, our understanding of how nitrogen-containing aerosols affect this remains limited; in particular, regarding the associated mechanisms. Using a fumigation particle generator, we generated ammonium nitrate solution (in four concentrations of 0, 15, 30, 60 kg N hm-2 year-1) into droplets, in 90% of which the diameters were less than 2.5 µm, in the range of 0.35-4 µm, and fumigated Iris germanica L. and Portulaca grandiflora Hook. for 30 days in April and August. We found that the weight percentage of nitrogen in the upper epidermis, mesophyll tissue, and bulk of leaves decreased significantly with the N addition rate, which caused a decrease of carbon:nitrogen ratio, due to the enhanced net photosynthetic rate. Compared with Portulaca grandiflora Hook., Iris germanica L. responded more significantly to the disturbance of N addition, resulting in a decrease in the weight percentage of nitrogen in the roots, due to a lower nitrogen use efficiency. In addition, the superoxide dismutase activity of the two plants was inhibited with a higher concentration of nitrogen sol; a reduction of superoxide dismutase activity in plants means that the resistance of plants to various environmental stresses is reduced, and this decrease in superoxide dismutase activity may be related to ROS signaling. The results suggest that inorganic nitrogen-containing aerosols caused excessive stress to plants, especially for Iris germanica L.