[Influence of Ammonium Sulfate and Ammonium Nitrate on the Properties of Ambient PM2.5 in Zhenjiang].

Recently, the contribution of inorganic salts (nitrates in particular) to the mass concentration of particulate matter with an aerodynamic diameter of less than 2.5 µm (PM2.5) has been increasing across China. However, it is urgent to understand how the increased inorganic salts affect the crucial properties of PM2.5. Here, we conducted continuous field observations at Zhenjiang Ecology and Environment Protection Bureau from January 1 to December 31, 2021. The mass concentrations of ammonium sulfate[(NH4)2SO4] and ammonium nitrate (NH4NO3) were calculated using different methods. The contributions of (NH4)2SO4 and NH4NO3 to the extinction coefficient, hygroscopic growth, and acidity of PM2.5 were discussed in detail. Our results demonstrated that the mean mass concentrations of (NH4)2SO4 and NH4NO3 during the study period were (6.5±4.5) and (15.0±13.3) µg·m-3, which contributed (20.5±18.2)% and (34.5±18.4)% to the mass concentration of PM2.5, respectively. The total extinction coefficient of PM2.5 was (224.5±194.2) Mm-1, in which NH4NO3 was the largest contributor[(40.1±20.9)%] followed by (NH4)2SO4[(19.1±10.8)%]. (NH4)2SO4 and NH4NO3 were also the dominant contributors to the hygroscopic growth of PM2.5. In particular, NH4NO3contributed from (53.8±13.4)% to (61.6±14.6)% to the aerosol water content of PM2.5 under pollution conditions. Thus, NH4NO3 was a key air pollutant to be targeted for further improving the visibility and air quality in Zhenjiang in the future. However, the reduction in the precursors of NH4NO3 would lead to an increase in aerosol acidity, particularly in the spring and winter seasons. Our results help us understand the evolution of air quality and the related impacts and also provide important information on air quality improvement in Zhenjiang in the future.

Targeting Delivery Nanocarriers for (+)-Terrein to Enhance Its Anticancer Effects.

As a compound from marine fungi, (+)-terrein showed significant anticancer activity. In this study, (+)-terrein was extracted from the marine-derived fungus and showed significant cytotoxicity against cancer cells, especially in A549 cells. To enhance its anticancer effects, redox-responsive nanocarriers based on folic acid-chitosan decorating the mesoporous silica nanoparticles were designed to control (+)-terrein target delivery into cancer cells. (+)-Terrein was loaded in the holes, and folic acid-chitosan worked as a gatekeeper by disulfide linkage controlling (+)-terrein release in the tumor microenvironment. The (+)-terrein drug delivery systems exhibited cytotoxicity toward A549 cells through induction of apoptosis. The apoptosis effect was confirmed by the increase in the expression of cleaved caspase-3, caspase-9, and PARP. Taken together, this work evaluates for the first time the (+)-terrein delivery system and provides a promising nanomedicine platform for (+)-terrein.

The use of polyion complex micelles to enhance the oral delivery of salmon calcitonin and transport mechanism across the intestinal epithelial barrier.

The objective of the present study was to demonstrate the effect of polyanionic copolymer mPEG-grafted-alginic acid (mPEG-g-AA)-based polyion complex (PIC) micelles on enhancing the oral absorption of salmon calcitonin (sCT) in vivo and in vitro and identify the transepithelial transport mechanism of PIC micelles across the intestinal barrier. mPEG-g-AA was first successfully synthesized and characterized in cytotoxicity. The PIC micelles were approximately of 72 nm in diameter with a narrow distribution. The extremely significant enhancement of hypocalcemia efficacy of sCT-loaded PIC micelles in rats was evidenced by intraduodenal administration in comparison with sCT solution. The presence of mPEG-grafted-chitosan in PIC micelles had no favorable effect on this action in the referred content. In the Caco-2 transport studies, PIC micelles could significantly increase the permeability of sCT across Caco-2 monolayers without significantly affecting transepithelial electrical resistance values during the transport study. No evident alterations in the F-actin cytoskeleton were detected by confocal microscope observation following treatment of the cell monolayers with PIC micelles, which further certified the incapacity of PIC micelles to open the intercellular tight junctions. In addition, TEM observations showed that the intact PIC micelles were transported across the everted gut sac. These suggested that the transport of PIC micelles across Caco-2 cell monolayers involve a predominant transcytosis mechanism via endocytosis rather than paracellular pathway. Furthermore, PIC micelles were localized in both the cytoplasm and the nuclei observed by CLSM. Therefore, PIC micelles might be a potentially applicable tool for enhancing the oral absorption of cationic peptide and protein drugs.

[Dynamic simulation of ammonia- and nitrate N leakage from paddy field under different N supply].

By using self-designed lysimeters, the dynamic changes of ammonia- and nitrate N leakage from the plowpan of paddy field under different N supply were studied, aimed to understand the N leakage loss from paddy field during rice growth period. A dynamic model was built to simulate the N translocation and transformation in rice plant, soil, and water by Vensim software. The data from the field experiment with N fertilization rates of 0, 75, 150, 225, 300, and 375 kg x hm(-2) in Yuhang district, Hangzhou City in 2003 were used for calibrating the model, and the data from the field experiment in 2007 were utilized for validating the model. The simulated N concentrations in the leakage fitted well with the observed data, suggesting that the simulated results were reliable and the model was applicable.

[Competitive sorption of mixed organic pollutants by soils].

Binary sorption equilibria were measured using three different loading methods: METHOD (1): Naphthalene loaded before phenanthrene; Method (2): Both Solutes loaded simultaneously; Method (3): Naphthalene loaded after phenanthrene. Each having 110 reactors and 10 levels of initial concentrations for both tested organic solutes. This is very different from previous studies which employed one single initial concentration of the primary solute and multiple concentration levels of the competitor and loaded both solutes simultaneously. Results indicate that the adsorption behavior of the same solute on the same sorbent with competing solute is distinctly different from its single adsorption behaviors. Naphthalene isotherm becomes more linear as phenanthrene concentration increases in the binary systems tested using all three loading methods. In contrast, phenanthrene isotherm remains nonlinear when it was loaded after or loaded simultaneously with naphthalene. It becomes more linear as a function of naphthalene concentration only when phenanthrene was loaded before naphthalene. The Koc values decrease as a function of competing solute concentration (c(e)), and approach to the lowest value when this c, is about 0.5 Sw. IAST provides better predictions for the sorption only when the competing solute is at lower c(e)(< 0.01 Sw). Large-size and more hydrophobic phenanthrene competes favorably with the small-size and relatively less hydrophobic naphthalene, and the heterogeneity of natural organic matter associated with the soil may have strong influence on the competitive phenomena between the tested solutes.