Enhanced Sulfate Formation through Synergistic Effects of Chlorine Chemistry and Photosensitization in Atmospheric Particles

Numerous studies have demonstrated that organic photosensitizers from biomass burning can generate oxidants to effectively convert inorganic and organic precursors into secondary aerosols. Particulate chloride ions can be internally mixed with organic photosensitizers in biomass burning particles. In this study, we investigate the impact of the interaction of chlorine chemistry and photosensitization on the oxidative potential of aerosols by utilizing SO2 oxidation to form sulfate as an indicator. Mixed particles of chloride with glyoxal and its reaction products of ammonia of imidazole-2-carboxaldehyde (IC) were studied. Premixed NH4Cl + glyoxal particles have a 4–5 times higher sulfate formation rate than premixed NaCl + glyoxal, particularly at low relative humidity, suggesting the role of photosensitization. Furthermore, the addition of IC resulted in an ∼73-fold increase in sulfate production rate compared to NH4Cl alone. No noticeable sulfate formation was observed in the presence of IC alone, likely due to the high particle acidity in this study (i.e., pH = 2). The kinetic analysis of these particles results yields a reaction rate constant of chloride ions with the triplet state of IC, 3IC*, ∼3 orders of magnitude higher than previously reported values in bulk solution. These findings underscore the significance of the synergetic effect of chlorine chemistry and photosensitization in enhancing atmospheric oxidative capacity

Nitrite/Nitrous Acid Generation from the Reaction of Nitrate and Fe(II) Promoted by Photolysis of Iron–Organic Complexes

Gaseous nitrous acid (HONO) has the potential to greatly contribute to the atmospheric oxidation capacity. Increased attention has been paid to in-particle nitrite or nitrous acid, N­(III), as one of the HONO sources. However, sources and formation mechanisms of N­(III) remain uncertain. Here, we study a much less examined reaction of Fe­(II) and nitrate as a source of N­(III). The N­(III) production was indirectly probed by its multiphase reaction with SO2 for sulfate production. Particles containing nitrate and Fe­(III) were irradiated for generating Fe­(II). Sulfate production was enhanced by the presence of UV and organic compounds likely because of the enhanced redox cycle between Fe­(II) and Fe­(III). Sulfate production rate increases with the concentration of iron–organic complexes in nitrate particles. Similarly, higher concentrations of iron–organic complexes yield higher nitrate decay rates. The estimated production rates of N­(III) under simulated conditions in our study vary from 0.1 to 3.0 μg m–3 of air h–1. These values are comparable to HONO production rates of 0.2–1.6 ppbv h–1, which fall in the values reported in laboratory and field studies. The present study highlights a synergistic effect of the coexistence of iron–organic complexes and nitrate under irradiation as a source of N­(III)

Additional file 1: of Good response to PAH-targeted drugs in a PVOD patient carrying Biallelic EIF2AK4 mutation

The detailed treatment course of the PVOD patient is below. (DOC 25 kb

Removal of ammonium and manganese from surface water using a MeO_x filter system as a pretreatment process

Residual aluminium from the coagulation–sedimentation process in the treatment of surface water can decrease the catalytic activity of a manganese co-oxide filter film (MeOx) used for ammonium and manganese removal. To solve this problem, a MeOx filter was used as a pretreatment process to filtrate source water directly before the coagulation and sedimentation treatment. The removal performance and the mechanism of change in the activity of MeOx were investigated. The experimental results indicated that the MeOx filter removed ammonium and manganese from surface water sources effectively, and its manganese removal activity was enhanced. The characteristics of MeOx were investigated via SEM, EDS, XPS, and the BET surface area. Analysis of the experimental results showed that the increase in the content of Al under this condition was much lower than that under treatment with the coagulation–sedimentation process. After long-term operation, the amount and surface area of MeOx coated on the filter sand increased significantly, leading to an increase in the catalytic activity. However, in cold water, the catalytic activity of MeOx decreased, and more Mn(II) was obtained on the surface of MeOx. Thus, the morphology of MeOx changed. Fortunately, when water temperature increases, the removal activity can recover immediately. By inactivating microorganisms and comparing the removal performance with that under other conditions, the MeOx activity of the pretreatment process is preserved effectively and no strengthening measures are required. This study will provide a new strategy for the use of the MeOx catalytic technology.</p

Theoretical Analysis of Plasmon Modes of Au–Ag Nanocages

The plasmonic properties of porous Au–Ag alloy nanocages are studied theoretically. The finite element method is used to investigate numerically the scattering and absorption spectra of two kinds of nanocages: corner-truncated and face-holed nanocages. Our results indicate that the plasmon modes of the two porous nanocages are nearly equivalent and tunable, which are redshifted from that of nanobox. The larger the surface porosity, the more redshifted the plasmon band is. However, the dependence of the plasmon band (dipole mode) on the surface porosity of the corner-truncated nanocage is higher than that of the face-holed one. The absorption efficiency of the former is higher than those of the latter at the same plasmon mode, whereas the scattering efficiency of the former is weaker. In addition, the bandwidth of the former is narrower than that of the latter. Our results also show that the scattering and absorption efficiencies of a corner-truncated nanocage illuminated by a plane wave normal to the {111} facet are stronger than those to the {100} facet at the same plasmon mode

Heterogeneous SO₂ Oxidation in Sulfate Formation by Photolysis of Particulate Nitrate

Heterogeneous oxidation of sulfur dioxide (SO2) is suggested to be one of the most important pathways for sulfate formation during extreme haze events in China, yet the exact mechanism remains highly uncertain. We propose a much less explored pathway for aqueous-phase SO2 oxidation for the formation of particulate sulfate by NO2 and OH radicals produced from photolysis of particulate nitrate. Reactive uptake experiments with SO2 and ammonium nitrate particles under ultraviolet irradiation show measured SO2 uptake coefficients of ∼10–5. Model calculations of sulfate production rates, comparing known mechanisms of oxidation by O3, NO2, H2O2, and transition metal ions, and the nitrate photolysis mechanism suggest that the nitrate photolysis pathway could contribute significantly to the overall sulfate production at pH 4–6. This study provides new insight into the current debate about sulfate production pathways under typical haze conditions in China

MOESM1 of Transcriptome-wide map of m6A circRNAs identified in a rat model of hypoxia mediated pulmonary hypertension

Additional file 1: Data S1. Differentially expressed m6A abundance in circRNAs

Understanding the Anchoring Effect of Two-Dimensional Layered Materials for Lithium–Sulfur Batteries

Although the rechargeable lithium–sulfur battery system has attracted significant attention due to its high theoretical specific energy, its implementation has been impeded by multiple challenges, especially the dissolution of intermediate lithium polysulfide (Li₂S_<i>n</i>) species into the electrolyte. Introducing anchoring materials, which can induce strong binding interaction with Li₂S_<i>n</i> species, has been demonstrated as an effective way to overcome this problem and achieve long-term cycling stability and high-rate performance. The interaction between Li₂S_<i>n</i> species and anchoring materials should be studied at the atomic level in order to understand the mechanism behind the anchoring effect and to identify ideal anchoring materials to further improve the performance of Li–S batteries. Using first-principles approach with van der Waals interaction included, we systematically investigate the adsorption of Li₂S_<i>n</i> species on various two-dimensional layered materials (oxides, sulfides, and chlorides) and study the detailed interaction and electronic structure, including binding strength, configuration distortion, and charge transfer. We gain insight into how van der Waals interaction and chemical binding contribute to the adsorption of Li₂S_<i>n</i> species for anchoring materials with strong, medium, and weak interactions. We understand why the anchoring materials can avoid the detachment of Li₂S as in carbon substrate, and we discover that too strong binding strength can cause decomposition of Li₂S_<i>n</i> species