Mackinawite nanozymes as reactive oxygen species scavengers for acute kidney injury alleviation.

BACKGROUND: Iron sulfide nanomaterials have been successfully employed as therapeutic agents for bacterial infection therapy and catalytic-ferroptosis synergistic tumor therapy due to their unique structures, physiochemical properties, and biocompatibility. However, biomedical research and understanding of the biological functions of iron sulfides are insufficient, and how iron sulfide nanomaterials affect reactive oxygen species (ROS) in diseases remains unknown. Acute kidney injury (AKI) is associated with high levels of ROS, and therefore nanomedicine-mediated antioxidant therapy has emerged as a novel strategy for its alleviation. RESULTS: Here, mackinawite nanozymes were synthesized from glutathione (GSH) and iron ions (Fe3+) (denoted as GFeSNs) using a hydrothermal method, and then evaluated as ROS scavengers for ROS-related AKI treatment. GFeSNs showed broad-spectrum ROS scavenging ability through synergistic interactions of multiple enzymes-like and hydrogen polysulfide-releasing properties. Furthermore, both in vitro and in vivo experiments demonstrated that GFeSNs exhibited outstanding cytoprotective effects against ROS-induced damage at extremely low doses and significantly improved treatment outcomes in AKI. CONCLUSIONS: Given the synergetic antioxidant properties and high biocompatibility, GFeSNs exhibit great potential for the treatment of AKI and other ROS-associated diseases.

Characteristics of atmospheric volatile organic compounds in urban area of Beijing: Variations, photochemical reactivity and source apportionment.

Atmospheric volatile organic compounds (VOCs) were observed by an on-line gas chromatography-flame ionization detector monitoring system from November 2016 to August 2017 in Beijing. The average concentrations were winter (40.27 ± 25.25 µg/m3) > autumn (34.25 ± 19.90 µg/m3) > summer (32.53 ± 17.39 µg/m3) > spring (24.72 ± 17.22 µg/m3). Although benzene (15.70%), propane (11.02%), ethane (9.32%) and n-butane (6.77%) were the most abundant species, ethylene (14.07%) and propene (11.20%) were the key reactive species to ozone formation potential (OFP), and benzene, toluene, ethylbenzene, m-xylene + p-xylene and o-xylene (54.13%) were the most reactive species to secondary organic aerosol formation potential (SOAFP). The diurnal and seasonal variations indicated that diesel vehicle emission during early morning, gasoline vehicle emission at the traffic rush hours and coal burning during the heating period might be important sources. Five major sources were further identified by positive matrix factorization (PMF). The vehicle exhaust (gasoline exhaust and diesel exhaust) was found to be contributed most to atmospheric VOCs, with 43.59%, 41.91%, 50.45% and 43.91%, respectively in spring, summer, autumn and winter; while solvent usage contributed least, with 11.10%, 7.13%, 14.00% and 19.87%, respectively. Biogenic emission sources (13.11%) were only identified in summer. However, both vehicle exhaust and solvent usage were identified to be the key sources considering contributions to the OFP and SOAFP. Besides, the contributions of combustion during heating period and gasoline evaporation source during warm seasons to OFP and SOAFP should not be overlooked.

Serious BTEX pollution in rural area of the North China Plain during winter season.

Atmospheric BTEX compounds (benzene, toluene, ethylbenzene and xylenes) in a rural site of the North China Plain (NCP) were preliminarily investigated in winter, and the outdoor concentrations (25.8-236.0 µg/m3) were found to be much higher than those reported in urban regions. The pollution of BTEX inside a farmer's house was even more serious, with combined concentrations of 254.5-1552.9 µg/m3. Based on the ratio of benzene to toluene (1.17±0.34) measured, the serious BTEX pollution in the rural site was mainly ascribed to domestic coal combustion for heating during the winter season. With the enhancement of farmers' incomes in recent years, coal consumption by farmers in the NCP is rapidly increasing to keep their houses warm, and hence the serious air pollution in rural areas of the NCP during winter, including BTEX, should be paid great attention.

Facile construction of Z-scheme AgCl/Bi3TaO7 photocatalysts for effective removal of tetracycline under visible-light irradiation.

A string of AgCl/Bi3TaO7 two-component composite was synthesized by hydrothermal and deposition-precipitation process initially. The photocatalytic activities of mixed-phase AgCl/Bi3TaO7 were evaluated toward the decomposition of tetracycline (TC). Among these as-prepared materials, AgCl/Bi3TaO7 nanocomposites when the molar ratio of baked materials between AgCl and Bi3TaO7 was 1:5 presented the optimal photocatalytic quantum efficiency for TC dissociation (86.82%) with visible-light exposure, which was 1.69 and 2.38 folders higher than that of single Bi3TaO7 and AgCl, respectively. What is more, it illustrated that the photo-generated carriers were markedly isolated on account of the formation of heterojunction confirmed by EIS analysis. Meanwhile, radical trapping experiments implied that the photo-induced holes (h+), hydroxyl radical (·OH), and superoxide radical (·O2-) were the major active species. The escalated photocatalytic activity could be ascribed to the unique construction of Z-scheme AgCl/Bi3TaO7 heterojunction, which could expedite charge separation and transmission, cement light absorption capability and retain the strong redox ability of photo-generated electrons and holes. Our finding suggests that AgCl/Bi3TaO7 nanocomposites possess great potential for photocatalytic oxidation of residual TC in the wastewater effluents and the reported strategy can contribute to the development of novel high-performance photocatalyst.

Spatial characterization of HCHO and reapportionment of its secondary sources considering photochemical loss in Taiyuan, China.

Formaldehyde (HCHO) plays an important role in atmospheric ozone (O3) formation. To accurately identify the sources of HCHO, carbonyls and volatile organic compounds (VOCs) were measured at three urban sites (Taoyuan, TY-U; Jinyuan, JY-U; Xiaodian, XD-U) and a suburban site (Shanglan, SL-B) in Taiyuan during a high O3 period (from July 20 to August 3, 2020). The average mixing ratio of HCHO at XD-U (8.1 ± 2.8 ppbv) was comparable to those at TY-U (7.4 ± 2.1 ppbv) and JY-U (7.0 ± 2.3 ppbv) but higher (p < 0.01) than that at SL-B (4.9 ± 2.3 ppbv). HCHO contributed to 54.3-59.9 % of the total ozone formation potentials (OFPs) of non-methane hydrocarbons (NMHCs) at four sites. The diurnal variation of HCHO concentrations reached a peak value at 12:00-15:00, which may be attributed to the strong photochemical reaction. To obtain more accurate source results of HCHO under the condition of photochemical loss, the initial concentrations of NMHCs were estimated based on photochemical age parameterization and incorporated into the positive matrix factorization (PMF) model (termed IC-PMF). According to the IC-PMF results, secondary formation (SF) contributed the most to HCHO at XD-U (35.6 %) and SL-B (25.1 %), whereas solvent usage (SU) (40.9 %) and coking sources (CS) (36.0 %) were the major sources at TY-U and JY-U, respectively. Compared to the IC-PMF, the conventional PMF analysis based on the observed data underestimated the contributions of SU (100.5-154.2 %) and biogenic sources (BS) (28.5-324.7 %). Further reapportionment of secondary HCHO by multiple linear regression indicated that SU dominated the sources of HCHO at SL-B (28.3 %) and TY-U (41.7 %), while industrial emissions (IE) and CS contributed the most to XD-U (26.6 %) and JY-U (43.0 %) in Taiyuan from north to south, respectively.

meta-Position synergistic effect induced by Ni-Mo co-doped WSe2 to enhance the hydrogen evolution reaction.

Transition metal dichalcogenides have been the most attractive two-dimensional layered materials for electrocatalytic hydrogen evolution due to their unique structure and multi-phase electronic states. However, the enhancement of the WSe2 electrocatalytic hydrogen evolution reaction (HER) performance by bimetal co-doping has been rarely reported. Herein, the NiMo-WSe2 catalyst has been synthesized by a one-step hydrothermal reaction, with lower overpotentials of 177 and 188 mV at a current density of 10 mA cm-2 in 0.5 M H2SO4 and 1 M KOH, respectively. The large specific surface area and thinner edge morphology provide more active sites for hydrogen production, thereby significantly improving the charge transfer kinetics. Density functional theory calculation results show that under acidic conditions the ΔGH* values of NiMo-WSe2 with different structures and hydrogen adsorption sites are also different, when the hydrogen adsorption site was located at the top of the Se-Ni bond, the meta NiMo-WSe2 has a ΔGH* value (-0.04 eV) that is closest to 0. Meanwhile, NiMo-WSe2 (meta) also has a minimum of ΔGH* under alkaline conditions. DOS confirmed that Ni doping has a large impact on the electronic states at the WSe2 Fermi level, while NiMo co-doping greatly reduces the potential energy barrier of the HER reaction, jointly increasing the current density, and thus improving the HER performance.

The thermal expansion exfoliation technology and lithium promoter assistant afford CuOx/graphene as a high-performance anode for lithium-ion batteries.

The ability to rationally design a copper oxide anode with superior rate performance that possesses an ultra-small particle size is highly desirable for lithium-ion batteries (LIBs). Herein, the rapid and effective thermal expansion exfoliation technology was employed to synthesize ultra-small CuOx nanoparticles (∼2.7 nm) uniformly dispersed on graphite oxide after popping (CuOx/Li-PGO), in which the addition of lithium promoted the exfoliation process to obtain an enlarged specific surface area and efficient transfer ability of PGO. The CuOx/Li-PGO electrode achieved a reversible capacity as high as 512.1 mA h g-1 under 2.0 A g-1 after 1000 cycles, demonstrating superior rate performance and cycling stability.

One-dimensional N-doped carbon nanofibers produced by pre-oxide treatment for effective lithium storage.

Amorphous carbon materials have been confirmed as attractive anode materials for lithium-ion batteries. Herein, an effective strategy to fabricate amorphous carbon materials at low temperature under air atmosphere is proposed. As demonstrated, one-dimensional nitrogen-doping carbon nanofibers were obtained through simple electrospinning technology, following low-temperature heat treatment. Meanwhile, the nitrogen-doping concentration can be regulated by the heating temperature, which can further introduce different levels of adsorption sites on the surface of carbon and enhance the electronic conductivity. Based on experimental investigation, carbon nanofibers with a high nitrogen doping concentration of 18.1 at% achieved an outstanding cycling durability (194.0 mA h g-1 at 2.0 A g-1 after 2000 cycles).