CeO2 microplates were synthesized by a sol-gel auto-combustion method. BiOBr nanosheets were then deposited onto the surface of CeO2 via a facile deposition–precipitation method with the assistance ...of ethylene glycol. The as-prepared BiOBr/CeO2 samples were characterized by various analytical techniques. The BC-2(Ce/Bi molar ratios is 2) sample exhibited the highest photocatalytic activity. The RhB was degraded (97.3%) under visible light irradiation within 20min. Furthermore, the BC-2 also exhibited superior degradation activity towards methyl blue (MB) and phenol. The enhanced photocatalytic performance could be ascribed to the enhanced light absorption and the improved separation of photogenerated charge carriers through forming a p-n heterojunction.
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•BiOBr/CeO2 was prepared via a deposition–precipitation method with the assistance of ethylene glycol.•The BC-2(Ce/Bi molar ratios is 2) sample exhibited the highest photocatalytic activity.•Enhanced photocatalytic activity was due to forming a p-n heterojunction between BiOBr and CeO2.
Cuspy shadow was first reported for hairy rotating black holes, whose metrics deviate significantly from the Kerr one. The non-smooth edge of the shadow is attributed to a transition between ...different branches of unstable but bounded orbits, known as the fundamental photon orbits, which end up at the light rings. In searching for a minimal theoretical setup to reproduce such a salient feature, in this work, we devise a toy model with axisymmetry, a slowly rotating Kerr black hole enveloped by a thin slowly rotating dark matter shell. Despite its simplicity, we show rich structures regarding fundamental photon orbits explicitly in such a system. We observe two disconnected branches of unstable spherical photon orbits, and the jump between them gives rise to a pair of cusps in the resultant black hole shadow. Besides the cuspy shadow, we explore other intriguing phenomena when the Maxwell construction cannot be established. We find that it is possible to have an incomplete arc of Einstein rings and a “fractured” shadow. The potential astrophysical significance of the corresponding findings is addressed.
In this work, n–p heterostructure SnO2/BiOI photocatalyst was successfully fabricated through a facile chemical bath method. The photocatalysts was applied to minimize antibiotic oxytetracycline ...hydrochloride (OTTCH) and methyl orange (MO) under visible light irradiation. SnO2/BiOI composite exhibited excellent photocatalytic performance for the refractory pollutant OTTCH and MO decomposition. The sample of 30 wt % SnO2/BiOI possessed the best photocatalytic performance in all the obtained catalysts. Several reaction parameters affecting OTTCH degradation such as initial concentration, ion species, and concentration were investigated systematically. The optical and electrical properties of materials demonstrate that the transfer rate of electron–hole pairs dramatically improve though forming an n–p junction in SnO2/BiOI hybrid. Moreover, the energy band alignments of SnO2/BiOI junction were confirmed via combining DRS and XPS analysis, which provided strong support for the proposed mechanism. This work could provide a new approach to construct new p–n junction photocatalysts and a reference for the study of other heterojunction catalysts.
Mixed matrix membranes (MMMs), conjugating the advantages of flexible processing‐ability of polymers and high‐speed mass transfer of porous fillers, are recognized as the next‐generation ...high‐performance CO2 capture membranes for solving the current global climate challenge. However, controlling the crystallization of porous metal‐organic frameworks (MOFs) and thus the close stacking of MOF nanocrystals in the confined polymer matrix is still undoable, which thus cannot fully utilize the superior transport attribute of MOF channels. In this study, the “confined swelling coupled solvent‐controlled crystallization” strategy is employed for well‐tailoring the in‐situ crystallization of MOF nanocrystals, realizing rapid (<5 min) construction of defect‐free freeway channels for CO2 transportation in MMMs due to the close stacking of MOF nanocrystals. Consequently, the fabricated MMMs exhibit approximately fourfold enhancement in CO2 permeability, i.e., 2490 Barrer with a CO2/N2 selectivity of 37, distinctive antiplasticization merit, as well as long‐term running stability, which is at top‐tier level, enabling the large‐scale manufacture of high‐performance MMMs for gas separation.
A facile and efficient “confined swelling coupled solvent‐controlled crystallization” strategy is demonstrated to control the in situ crystallization of metal‐organic frameworks nanocrystals in polyethylene oxide membranes, realizing rapid construction of defect‐free freeway channels for CO2 transportation in mixed matrix membranes (MMMs). The optimized MMM showed fourfold enhancement in CO2 permeability, i.e., 2705 Barrer, with a CO2/N2 selectivity of 37.
Arbuscular mycorrhiza can improve the salt-tolerance of host plant. A systematic study of mycorrhizal plant responses to salt stress may provide insights into the acquired salt tolerance. Here, the ...transcriptional profiles of mycorrhizal Sesbania cannabina shoot and root under saline stress were obtained by RNA-Seq. Using weighted gene coexpression network analysis and pairwise comparisons, we identified coexpressed modules, networks and hub genes in mycorrhizal S. cannabina in response to salt stress. In total, 10,371 DEGs were parsed into five coexpression gene modules. One module was positively correlated with both salt treatment and arbuscular mycorrhizal (AM) inoculation, and associated with photosynthesis and ROS scavenging in both enzymatic and nonenzymatic pathways. The hub genes in the module were mostly transcription factors including WRKY, MYB, ETHYLENE RESPONSE FACTOR, and TCP members involved in the circadian clock and might represent central regulatory components of acquired salinity tolerance in AM S. cannabina. The expression patterns of 12 genes involved in photosynthesis, oxidation-reduction processes, and several transcription factors revealed by qRT-PCR confirmed the RNA-Seq data. This large-scale assessment of Sesbania genomic resources will help in exploring the molecular mechanisms underlying plant-AM fungi interaction in salt stress responses.
The polycyclic aromatic hydrocarbon (PAH)-degrading strain Q8 was isolated from oilfield produced water. According to the analysis of a biochemical test, 16S rRNA gene, house-keeping genes and ...DNA-DNA hybridization, strain Q8 was assigned to a novel species of the genus
. The strain could not only grow in mineral salt medium (MM) and utilize naphthalene and pyrene as its sole carbon source, but also degraded mixed naphthalene, phenanthrene, anthracene and pyrene. The degradation ratio of these four PAHs reached 100%, 95.4%, 73.8% and 53.4% respectively after being degraded by Q8 for seven days. A comparative experiment found that the PAHs degradation efficiency of Q8 is higher than that of
and
, which have the capacities to remove PAHs. Fourier transform infrared spectra, saturate, aromatic, resin and asphaltene (SARA) and gas chromatography-mass spectrometry (GC-MS) analysis of crude oil degraded by Q8 were also studied. The results showed that Q8 could utilize
-alkanes and PAHs in crude oil. The relative proportions of the naphthalene series, phenanthrene series, thiophene series, fluorene series, chrysene series, C21-triaromatic steroid, pyrene, and benz(a)pyrene were reduced after being degraded by Q8.
sp. nov. Q8 had the capacity to remediate water and soil environments contaminated by PAHs or crude oil, and provided a feasible way for the bioremediation of PAHs and oil pollution.
The phase function is a useful tool to study all observations of space missions, since it can give all the information about light propagation in a gravitational field. For the extreme accuracy of ...the modern space missions, a precise relativistic modeling of observations is required. So, we develop a recursive procedure enabling us to expand the phase function into a perturbative series of ascending powers of the Newtonian gravitational constant. Any nth-order perturbation of the phase function can be determined by the integral along the straight line connecting two point events. To illustrate the result, we carry out the calculation of the phase function outside a static, spherically symmetric body up to the order of G2. Then, we develop a precise relativistic model that is able to calculate the phase function and the derivatives of the phase function in the gravitational field of rotating and uniformly moving bodies. This model allows the computing of the Doppler, radio science, and astrometric observables of the space missions in the Solar System. With the development of space technology, the relativistic corrections due to the motion of a planet’s spin must be considered in the high-precision space missions in the near future. As an example, we give the estimates of the relativistic corrections on the observables about the space missions TianQin and BEACON.
Background and Aim
The aim of this study is to explore the roles of estrogen receptor (ER) subtypes and corresponding agonists/antagonists on the development of cirrhosis and activation and ...proliferation of hepatic stellate cells (HSCs).
Methods
Carbon tetrachloride (CCl4)‐induced cirrhotic ovariectomized rats were administered non‐selective ER agonist (β‐estradiol, E2), ER selective agonists (ERα agonist, propylpyrazoletriol; ERβ agonist, diarylpropionitrile DPN; and G‐protein‐coupled ER GPER agonist, G1), or E2 + ER selective antagonists (ERα antagonist, MPP; ERβ antagonist, PHTPP; and GPER antagonist, G15) for 12 weeks. The expression of the three ER subtypes in livers and HSCs and the effects of the drugs on hepatic fibrosis, isolated HSCs, and uteri were evaluated.
Results
Selective ER agonists/antagonists had various effects on CCl4‐induced cirrhosis. The cirrhotic rats in the CCl4 + E2, CCl4 + DPN, CCl4 + E2 + MPP, and CCl4 + E2 + G15 groups presented reduced fibrosis scores, compared with those in the CCl4 group. The cirrhotic rats in the E2 + PHTPP group presented increased fibrosis scores that similar to those in the CCl4 group. The ovariectomized rats had enlarged uteri with increased uterus indexes after E2 administration; however, the proliferative effects of E2 were partially blocked by MPP or G15, but not PHTPP. In the in vitro study, DPN attenuated the transformation of quiescent HSCs to activated phenotype, suppressed collagen I, and α‐smooth muscle actin expression. DPN also suppressed platelet‐derived growth factor‐induced proliferation in cultured HSCs, which was reversed by PHTPP.
Conclusions
The antifibrogenic effects of estrogen were mediated by ERβ but not ERα or GPER. The ERβ selective agonist exerted a fibrosuppressive effect by inhibiting the activation and proliferation of HSCs, but did not induce uterine hyperplasia.
A Concise Total Synthesis of (−)‐Berkelic Acid Cheng, Hong‐Gang; Yang, Zhenjie; Chen, Ruiming ...
Angewandte Chemie International Edition,
March 1, 2021, Letnik:
60, Številka:
10
Journal Article
Recenzirano
Reported here is a concise total synthesis of (−)‐berkelic acid in eight linear steps. This synthesis features a Catellani reaction/oxa‐Michael cascade for the construction of the isochroman ...scaffold, a one‐pot deprotection/spiroacetalization operation for the formation of the tetracyclic core structure, and a late‐stage Ni‐catalyzed reductive coupling for the introduction of the lateral chain. Notably, four stereocenters are established from a single existing chiral center with excellent stereocontrol during the deprotection/spiroacetalization process. Stereocontrol of the intriguing deprotection/spiroacetalization process is supported by DFT calculations.
A concise total synthesis of (−)‐berkelic acid in eight linear steps was developed. This synthesis features a Catellani reaction/oxa‐Michael cascade for the construction of the isochroman scaffold, a one‐pot deprotection/spiroacetalization operation for the formation of tetracyclic core structure, and a late‐stage Ni‐catalyzed reductive coupling for the introduction of the lateral chain.
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