Zinc oxide nanoparticles (ZnO NPs) show adverse impacts on aerobic denitrifying bacteria, little is known about the response of these bacteria to ZnO NPs exposure at cellular level. This study assessed the multiple responses of Pseudomonas aeruginosa PCN-2 under ZnO NPs exposure. We demonstrated that ZnO NPs exposure could inhibit the intracellular metabolism and stimulate the antioxidant defence capability of PCN-2. At lower exposure concentration (5 mg/L), exogenous ROS generated and resulted in the inhibition of pyruvate metabolism and citrate cycle, which caused deficient energy for aerobic denitrification. At higher concentrations (50 mg/L), endogenous ROS additionally generated and triggered to stronger down-regulation of oxidative phosphorylation, which caused suppressed electron transfers for aerobic denitrification. Meanwhile, ZnO NPs exposure promoted EPS production and biofilm formation, and antioxidases was especially particularly stimulated at higher concentration. Our findings are significant for understanding of microbial bacterial susceptibility, tolerance and resistance under the exposure of ZnO NPs.
Marine oil spills may cause huge economic loss and detrimental effects to the coastal ecosystem and communities. In this study, a green and responsive washing fluid was developed by modifying the nanoclay with a nonionic surfactant to wash the stranded oil on beach sand. The characterization results showed changes in the basal spacing, absorption peaks, thermal degradation, surface morphology, and element weights after modification, indicating the surfactant was successfully loaded onto the nanoclay. Batch tests were conducted to investigate the effect of washing time, temperature, salinity, pH, and the modified nanoclay concentration on washing performance. The two-level factorial analysis revealed that salinity was the most significant environmental factor to the oil removal efficiency. It also indicated the interactions of temperature with salinity and salinity with the modified nanoclay concentration were significant to the response. The separation tests suggested the addition of calcium chloride could dramatically reduce the turbidity and the oil concentration in the washing effluent. In addition, the thermodynamic miscibility model was applied to explore oil/water miscibility in the presence of the modified nanoclay, and the results were in good agreement with experiments. The proposed green and responsive washing fluid with nonionic surfactant-modified nanoclay in this study has great potential in shoreline cleanup.
Members of the tripartite motif (TRIM) protein family strongly induced by interferons (IFNs) are parts of the innate immune system with antiviral activity. However, it is still unclear which TRIMs could play important roles in hepatitis B virus (HBV) inhibition. Here, we identified that TRIM56 expression responded in IFN-treated HepG2-NTCP cells and HBV-infected liver tissues, which was a potent IFN-inducible inhibitor of HBV replication. Mechanistically, TRIM56 suppressed HBV replication via its Ring and C-terminal domain. C-terminal domain was essential for TRIM56 translocating from cytoplasm to nucleus during HBV infection. Further analysis revealed that TRIM56's Ring domain targeted IκBα for ubiquitination. This modification induced phosphorylation of p65, which subsequently inhibited HBV core promoter activity, resulting in the inhibition of HBV replication. The p65 was found to be necessary for NF-κB signal pathway to inhibit HBV replication. We verified our findings using HepG2-NTCP and primary human hepatocytes. Our findings reveal that TRIM56 is a critical antiviral immune effector and exerts an anti-HBV activity via NF-κB signal pathway, which is essential for inhibiting transcription of HBV covalently closed circular DNA.
Conversion of digestate into biochar-based catalysts is an effective strategy for disposal and resource utilization. The active sites on biochar correlated with reactive species formation in peroxymonosulfate (PMS) system directly. Clarifying the structure-performance relationship of digestate derived biochar in PMS system was essential for decomposition of contaminants. Herein, dairy manure digestate derived biochar (DMDB) was prepared for PMS activation and sulfamethoxazole (SMX) degradation. The higher pyrolysis temperature could promote effective sites generation. Especially, the DMDB-800 catalyst exhibited excellent performance for PMS activation, achieving 90.2% degradation of SMX within 60 min. Based on the correlation analysis between log (k) values and active sites, defects, graphite N and CO were identified as dominant sites for PMS activation. The 1O2 oxidation and surface electron transfer were critical routes for SMX degradation. Besides, the degradation pathways of SMX were proposed according to DFT calculations and intermediates determination. The cleavage of the sulfonamide bond, hydroxylation of the benzene ring and oxidation of the amino group mainly occurred during SMX degradation. Overall, this study provides deep insights into the enhanced mechanism of tunable active sites on DMDBs for PMS activation, boosting the application of digestate biochar for water treatment in advanced oxidation systems.
ABSTRACT Numerous approaches have been used to modify graphitic carbon nitride (g-C3N4) for improving its photocatalytic activity. In this study, we demonstrated a facial post-calcination method for modified graphitic carbon nitride (g-C3N4-Ar/Air) to direct tuning band structure, i.e., bandgap and positions of conduction band (CB)/valence band (VB), through the control of atmospheric condition without involving any additional elements or metals or semiconductors. The synthesized g-C3N4-Ar/Air could efficiently degrade sulfamethazine (SMT) under simulated solar light, i.e., 99.0% removal of SMT with rate constant k1 = 2.696 h−1 within 1.5 h (4.9 times than pristine g-C3N4). Material characterizations indicated that the damaged/partial-collapsed structure and decreased nanosheet-interlayer distance for g-C3N4-Ar/Air resulted in the shift of band structure due to the denser stacking of pristine g-C3N4 through oxidative exfoliation and planarization by air calcination. In addition, the bandgap of g-C3N4-Ar/Air was slightly shrunk from 2.82 eV (pristine g-C3N4) to 2.79 eV, and the CB was significantly upshifted from −0.44 eV (pristine g-C3N4) to −0.81 eV, suggesting the powerful ability for donating the electrons for O2 to form •O2−. Fukui index (f –) based on theoretical calculation indicated that the sites of SMT molecule with high values, i.e., N9, C4 and C6, preferred to be attacked by •O2− and •OH, which is confirmed by the intermediates’ analysis. The tuning method for graphitic carbon nitride provides a simple approach to regulate the charge carrier lifetime then facilitate the utilization efficiency of solar light, which exhibits great potential in efficient removal of emerging organic contaminants from wastewater.
A novel g-C3N5/Bi4O5Br2 surface heterojunction was developed via in-situ growth of Bi-rich Bi4O5Br2 on g-C3N5 nanosheets. The optimal composite achieved 3.6- and 16.0- times of sulfathiazole (STZ) degradation activity when compared with pristine Bi4O5Br2 and g-C3N5. The interlayer stacking morphology and extra nitrogen in triazine units significantly narrowed the conduction band of g-C3N5, which greatly promoted its visible utilization; while the bismuth-rich property of Bi4O5Br2 prolonged the excited charge carrier lifetime. Both photoluminescence and electrochemical impedance spectroscopy analysis demonstrated that the type-II surface heterojunction (g-C3N5/Bi4O5Br2) offered remarkable charge transfer and separation due to the matched energy band structure. The STZ degradation mechanism and pathways were proposed based on experiments and density functional theory calculation, and the contribution of reactive species for STZ degradation followed the order of O2∙- > h+ > OH. Moreover, the toxicity evolution of STZ was evaluated, suggesting that sufficient mineralization is required to ensure safe discharge. The Box-Behnken experimental design methodology study revealed that g-C3N5/Bi4O5Br2 exhibited high reactivity for antibiotics degradation under different water matrix. This study suggested that g-C3N5/Bi4O5Br2 has great application potential for cost-effective remediation of persistent organic contaminants by using solar light.
Forecasting is an indispensable element of operational research (OR) and an important aid to planning. The accurate estimation of the forecast uncertainty facilitates several operations management activities, predominantly in supporting decisions in inventory and supply chain management and effectively setting safety stocks. In this paper, we introduce a feature-based framework, which links the relationship between time series features and the interval forecasting performance into providing reliable interval forecasts. We propose an optimal threshold ratio searching algorithm and a new weight determination mechanism for selecting an appropriate subset of models and assigning combination weights for each time series tailored to the observed features. We evaluate our approach using a large set of time series from the M4 competition. Our experiments show that our approach significantly outperforms a wide range of benchmark models, both in terms of point forecasts as well as prediction intervals.
Growing national decarbonization commitments require rapid and deep reductions of carbon dioxide emissions from existing fossil-fuel power plants. Although retrofitting existing plants with carbon capture and storage or biomass has been discussed extensively, yet such options have failed to provide evident emission reductions at a global scale so far. Assessments of decarbonization technologies tend to focus on one specific option but omit its interactions with competing technologies and related sectors (e.g., water, food, and land use). Energy system models could mimic such inter-technological and inter-sectoral competition but often aggregate plant-level parameters without validation, as well as fleet-level inputs with large variability and uncertainty. To enhance the accuracy and reliability of top-down optimization models, bottom-up plant-level experience accumulation is of vital importance. Identifying sweet spots for plant-level pilot projects, overcoming the technical, financial, and social obstacles of early large-scale demonstration projects, incorporating equity into the transition, propagating the plant-level potential to generate fleet-level impacts represent some key complexity of existing fossil-fuel power plant decarbonization challenges that imposes the need for a serious re-evaluation of existing fossil fuel power plant abatement in energy transition.