Rare earth element cerium (Ce) with variable valence states Ce 4+ /Ce 3+ is doped in the TiO 2 photoanode for dye-sensitized solar cells (DSSCs). The anatase crystalline phase keeps unchanged, while the crystalline size decreases slightly after Ce doping. The Ce positively changes the conduction band minimum of TiO 2 due to the unoccupied Ce-4f trap states in the band gap, and the Ce 4+ is reduced to Ce 3+ when electrons are injected in the photoanode. The ceriumdoped photoanodes with special electrochemical properties severely influence the performance of DSSCs. Due to the increased electron injection, the small Ce content (0.05% and 0.1%) doped TiO 2 photoanodes improve the performance of DSSCs which is optimized to 7.65% with Ce0.1% doping (1 sun, AM1.5) compared with the one with a pure TiO 2 photoanode (7.2%). However, the Ce 4+ states effectively trap electrons in the photoanode with further increase of Ce from 0.3 to 0.9%, which is confirmed by the charge extraction method and electrochemical impedance spectroscopy (EIS); thus, it suppresses the photocurrent and the efficiency of the DSSCs but is helpful to the fill factor improvement. The trap states, mainly resting on the TiO 2 crystalline surface, are verified and effectively passivized by TiCl 4 surface treatment.
Emodin is a main anthraquinone compound which exists in Chinese traditional medicines including Polygonum multiflorum and Rhubarb. It is documented to have obvious liver and kidney toxicity. This study aims to (a) estimate gender differences of the hepatotoxicity and toxicokinetics in rats after oral administration of emodin (60 and 150 mg/kg/d) for a consecutive 28 days and (b) clarify relative mechanisms caused by glucuronidation and disposition. Hepatotoxicity was significantly higher in female rats than that in male rats, as evidenced by histopathological and biochemical tests. Similarly, the toxicokinetic profiles of emodin have time and gender differences, which could cause time and gender differences in hepatotoxicity. The metabolic and transcriptomics data of 55 human liver and 36 human kidney samples demonstrated that UDP-glucuronosyltransferase 2B7 (UGT2B7) was the predominant enzyme for emodin glucuronidation. A genome-wide association study (GWAS) identified that rs11726899 located within ∼50 kb of the transcript of UGT2B could significantly affect emodin metabolism. Knockdown of UGT2B7 in HepG2 cells significantly decreased emodin glucuronidation and increased cytotoxicity of emodin. The gene expression and protein levels of UGT2B7 were decreased, but those of the multidrug-resistant-protein 2 (MRP2) were increased in HepG2 cells after being treated with 50 μM emodin for 48 h. Long-term use of emodin could decrease the intrinsic clearance (CL, decreased by 18.5%-35.4%) values of zidovidue (UGT2B7 substrate) glucuronide in both male and female liver microsomes from rats administrated with emodin for 28 days, thus causing the accumulation of emodin. However, higher self-induced MRP2 expression and lower hepatotoxicity were observed in emodin-treated male rats compared to that in female rats. Therefore, gender differences in the hepatotoxicity and toxicokinetics of emodin are potentially mediated by the coupling of UGT2B7 and MRP2 in vivo.
The fluxes of sensible heat (H) and latent heat (LE), which are generally the important parts of the energy and mass balances over glacier surfaces, are widely quantified by the bulk method. However, due to the difficulty of determining the aerodynamic roughness length z 0m in this method, H and LE values may still have large uncertainties with significant inaccuracy. To acquire reliable varying and intrinsic z 0m values, new simpler parameterizations for z 0m values at different ranges of the friction velocity u *b were fitted in this study. The method was implemented using the related meteorological data and glacial sublimation/condensation measured at the top of the August-one glacier (4817 m asl) in the Qilian Mountains from 1 July 2016 to 15 August 2017. The parameterization shows that z 0m increased sharply when u *b exceeded 0.43 m/s (the approximate threshold value) and that the effect of snowdrift was slight for the hourly z 0m values in the range 0.15 ≤ u *b ≤ 0.43 m/s, which could thus be used to calculate the daily z 0m . During the wet period (, the turbulent fluxes calculated by the bulk method showed that net radiation R net was the primary source of surface energy (60.7 w/m 2 ), whereas during the dry period (25 September 2016 to 4 May 2017), the main heat sink was the positive H (28.5 w/m 2 ) rather than the negative R net (À10.0 w/m 2 ). Plain Language SummaryThe profile method and the bulk method have been applied to quantify turbulent fluxes and sublimation/condensation, and the bulk method is more widely used because it is insensitive to observation errors. However, determination of the aerodynamic roughness lengths in the bulk method remains a large challenge. So we tried to acquire reliable varying and intrinsic roughness length for momentum through its parametric analysis. The related meteorological data and glacial sublimation/ condensation were measured over a mountain glacier. Hourly roughness lengths in the transitional range affected slightly by snowdrift were found with the approximate threshold value. The comparison provided here verifies that these values are reliable, although this method is relatively rough. The z 0m parameterization can be regarded as an important basis of turbulent heat flux research. Therefore, in addition to z 0m parameterization, it can also be very meaningful to further discuss the temporal variation of meteorology and turbulent heat fluxes. Further research is needed and very important to improve our understanding of energy and mass exchange between the glacier surface and atmosphere, especially in arid and semiarid regions.
Coal mining subsidence is a common human geological disaster that was particularly conspicuous in China. It seriously restricts the sustainable development of mining areas, and it not only damages land resources but also triggers a series of ecological and environmental problems that may result in social and economic issues. This report studied the coal mining subsidence area of Longkou in Shandong province and uses digital elevation data (DEM) of the mining area before subsidence in 1978 as the baseline elevation. Through image algorithms, we obtained coal mining subsidence region data for 1984, 1996, 2000, and 2004. And with spatial data sources of the same period of TM/ETM ? and SPOT5 remote sensing images, BP artificial neural network (BPNN) classification is used to extract surface landscape information in the subsidence area. With the support of GIS technology, superimposing subsidence area on the surface landscapeusing the largest landscape ecology patch index, landscape shape index, landscape condensation index, and the index of landscape distribution-report analyzes the mining landscape changes before and after subsidence. This study also carries on exploratory research with the landscape changes, thereby providing a scientific basis for integrated prevention and treatment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.