RESUMEN

Flavonoids, which contain a benzo-γ-pyrone (C6-C3-C6) skeleton, have been reported to exhibit effective antioxidant ability. This study aimed to compare the antioxidant activities of 7,8-dihydroxyflavone (7,8-DHF) and 7-hydroxyflavone (7-HF) in H2 O2 , lipopolysaccharide (LPS), or tert-butyl hydroperoxide (t-BHP)-induced RAW264.7 cells, respectively. The antioxidant capacities of 7,8-DHF and 7-HF were firstly evaluated by 2,2-azinobis-3-ethyl-benzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Then, reactive oxygen species (ROS), super oxide dismutase (SOD), and malondialdehyde (MDA) productions in H2 O2 , LPS, or t-BHP-induced RAW264.7 cells were tested and compared, respectively. Finally, the antioxidant mechanisms of 7-HF and 7,8-DHF were initially investigated by western blot. Our results showed that 7,8-DHF possessed stronger free-radical scavenging capacity than 7-HF. Both 7,8-DHF and 7-HF suppressed MDA production and ROS accumulation, improved the activity of SOD in H2 O2 , LPS, or t-BHP-induced RAW264.7 cells, respectively. And 7,8-DHF exerted a better antioxidant effect than 7-HF, especially in t-BHP-induced oxidative stress. Mechanically, 7,8-DHF prevented the activation of poly ADP-ribosepolymerase and caspase-3, meanwhile markedly upregulated the expression of HO-1 protein in t-BHP-induced oxidative stress. These results suggested that 7,8-DHF might serve as a potential pharmaceutical drug against oxidative stress injury.

Asunto(s)

RESUMEN

The treatment of polluted water is a serious environmental problem in the world. Biomass is easily modified and can be prepared into adsorbent materials, which is expected to solve the problem of heavy metal ion adsorption in sewage. In this paper, esterified tobacco straw based hydrogels (ETS-PAA) were synthesized from waste tobacco straw biomass. The structure and thermal stability of these hydrogels were characterized by FTIR, SEM, EDS, XPS and TG. The adsorption of metal ions by the hydrogel was measured by ICP-MS. The effects of initial ion concentration, adsorption time, pH, and temperature on the heavy metal adsorption were investigated. The results showed that ETS-PAA possessed more pores, which led to a better adsorption capacity. The maximum adsorption amounts of Pb2+, Cu2+ and Cd2+ were 2.41 mmol·g-1, 1.93 mmol·g-1 and 1.77 mmol·g-1, respectively. Finally, the adsorption mechanism and kinetics were analyzed. The adsorption was mainly accomplished by ion exchange of -COOK on the monomer chain with heavy metal ions, coordination of -OH and -CONH with heavy metal ions and interaction of ester bond, -COOH with heavy metal ions. The adsorption process was in accordance with the pseudo-second-order kinetic model and Freundlich model. The adsorption process belonged to multilayer chemisorption. This work shows that ETS-PAA was a promising material for the removal of heavy metal pollutants from aqueous solution.

Asunto(s)

RESUMEN

This paper aims at facilitating the developments of solar photovoltaic (PV) power and wind power generations to reduce carbon emission and achieve the carbon neutralization. The main novelty of this study is developing a new partnership comprised by the green energy investment company (GEIC), solar power plant (SPP), and offshore wind power plant (OWPP) and analyzing the impacts of typical factors on the coordinated development of SPP and OWPP based on the evolutionary game theoretical method. By using a tripartite evolutionary game model, the stability analysis of equilibrium strategy is carried out. The simulation results show that stable states could be realized under different partnerships. Impact investigation results of typical influential factors on all participants indicate that longer annual operation time, higher price of electricity sold to the power grid, and larger government subsidy will lead to more incomes for the SPP and OWPP, which will strengthen the participation willingness of all participants. For this study, the on-grid price of the SPP should be greater than 0.054 $/kWh. A reasonable investment ratio of the SPP and OWPP is the guarantee for the smooth development of the PPP project, which is suggested to be 4:6 in this study. The results of the current study have certain reference value for the policy and strategy formulations for facilitating the developments of solar PV power and offshore wind power generations.

Asunto(s)

RESUMEN

An innovative solar concentrating beam splitting photovoltaic thermal (CBS-PVT) system using a half-trough concentrator (HTC) and a film spectrum filter (FSF) is proposed and studied in this study. The FSF used for this system is designed and its average reflectivity and transmissivity are 0.272 and 0.728 for the full spectrum range. Performance evaluation results of the CBS-PVT system reveal the design correctness of the system. When the N-S solar tracking error (STE) rises to 0.15°, the optical efficiency of the entire CSB-PVT system can be kept at 0.8653, showing good adaptable capacity to the STE. The operation feasibility analysis shows that the PV efficiency of the PV subsystem (PVS) is 0.314 and the overall system efficiency overall is 0.26. Parametric analysis results indicate that when the solar thermal collector tube (TCT) operating temperature rises, the total power and overall efficiency of the CSB-PVT system both rise first and then decrease. When the TCT temperature is about 225 °C, the CBS-PVT system reaches its maximum output power of 1003.6 W and the maximum overall efficiency of 0.261. When the PV cell module (PVCM) temperature increases, the total power and overall efficiency of the CBS-PVT system decrease linearly. When the PVCM temperature rises to 50 °C, the two parameters decrease to 952.9 W and 0.248.

RESUMEN

In this work, a porous tobacco straw-based polyacrylic acid hydrogel STS-PAA with high adsorption performance was prepared by polymerizing pretreated waste tobacco straw (TS) with acrylic acid/potassium acrylate by UV radiation initiation. The adsorption performance of metal ions was investigated. The effects of different temperatures (25°C, 35°C, and 45°C), adsorption times (1-420 min), pH values (2.0-6.0) and initial concentrations (0.25-4.0 mmol L-1) of metal ions on the adsorption amount of heavy metal ions were investigated. The results showed that the hydrogel had a high removal rate of Pb2+, Cd2+ and Hg2+ in aqueous solution. The adsorption of Pb2+ was particularly effective. When C0 = 4.0 mmol L-1, pH = 6, the equilibrium adsorption amount of Pb2+, Cd2+ and Hg2+ reached 1.49 mmol g-1, 1.02 mmol L-1 and 0.94 mmol g-1, respectively. The chemical structure and morphology of the hydrogels were characterized by FT-IR, EDS, SEM and XPS. The Langmuir model fits well with the adsorption system. The kinetic data suggest the adsorption of Pb2+, Cd2+ and Hg2+ follow the pseudo-first-order model. This indicates that STS-PAA adsorption of three heavy metal ions is monolayer physical adsorption. Thermodynamic analysis shows that the adsorption of Pb2+, Cd2+ and Hg2+ by STS-PAA is an endothermic (ΔH>0) entropy increase (ΔS>0) non-spontaneous reaction.

RESUMEN

Mitochondria-targetable fluorescent chemosensors, Rhodamine-B and rhodamine 6G bearing syringaldehyde based receptors were designed and synthesized for efficient chemosensing of Zinc(II) ions. The probes showed the very selective naked eye color change to pink from colorless upon addition of Zinc(II) ions, further these probes showing turn-on fluorescence enhancement with Zn(II) ions by opening of rhodamine spirolactam. The probes are very sensitive towards Zn(II) ions among other ions. These probes RBS and R6S will be applicable to detect zinc ions upto the low level concentration 0.18 and 0.19 nano molar respectively. The affinity of these sensors RBS and R6S for Zinc (II) ions was found to be in the range of 1.12 × 104 M-1 and 7.28 × 104 M-1 respectively. 1H-nmr titrations of the probes with Zn(II) ions clearly indicating the spiroring opening of the spirolactam. DFT calculations supporting that the perceived photophysical changes of the probes on appendage of the zinc ions. Probes RBS and R6S are useable for selective staining mitochondria. Both of the probes are applicable to reveal labile Zn(II) in live Hela and MCF-7 cells via fluorescence imaging. RBS and R6S are also finding application on quantification of Zinc(II) ions inside mitochondria via fluorescence imaging.

Asunto(s)

RESUMEN

Solar thermal power and nuclear power generations are two most promising clean energy power approaches, which are effective for reducing carbon emissions. In order to promote the coordinated development of solar thermal power and nuclear power in China under the background of carbon neutral, the current paper develops a partnership comprised by the energy investment company (EIC), solar thermal power plant (STPP) and nuclear power plant (NPP). By utilizing the evolutionary game theory method and current policies of China, the evolutionary process simulations of the three participants under different conditions are conducted, which demonstrate that steady states could be achieved under different partnerships. Impact investigation results of typical influential factors indicate that longer annual operation time of power plant, larger subsidy and higher electricity price sold to the power grid are favorable to promote the partnership smoothly. Suitable investment ratio of the STPP and NPP should be considered as a larger investment ratio of the STPP and NPP has incentive influence on EICs and STPPs but inhibiting impact on NPPs. The results of the current study have certain reference value for the policy and strategy formulations for facilitating the developments of solar thermal power and nuclear power generations.

Asunto(s)