Developing high-efficient afterglow from metal-free organic molecules remains a formidable challenge due to the intrinsically spin-forbidden phosphorescence emission nature of organic afterglow, and ...only a few examples exhibit afterglow efficiency over 10%. Here, we demonstrate that the organic afterglow can be enhanced dramatically by thermally activated processes to release the excitons on the stabilized triplet state (T
) to the lowest triplet state (T
) and to the singlet excited state (S
) for spin-allowed emission. Designed in a twisted donor-acceptor architecture with small singlet-triplet splitting energy and shallow exciton trapping depth, the thermally activated organic afterglow shows an efficiency up to 45%. This afterglow is an extraordinary tri-mode emission at room temperature from the radiative decays of S
, T
, and T
. With the highest afterglow efficiency reported so far, the tri-mode afterglow represents an important concept advance in designing high-efficient organic afterglow materials through facilitating thermally activated release of stabilized triplet excitons.
Summary
Acid mine drainage (AMD) generated by rare earth elements (REEs) deposits exploration contains high concentrations of REEs, ammonium and sulfates, which is quite different from typical ...metallic AMD. Currently, microbial responses and ecological functions in REEs‐AMD impacted rivers are unknown. Here, 16S rRNA analysis and genome‐resolved metagenomics were performed on microbial community collected from a REEs‐AMD contaminated river. The results showed that REEs‐AMD significantly changed river microbial diversity and shaped unique indicator species (e.g. Thaumarchaeota, Methylophilales, Rhodospirillales and Burkholderiales). The main environmental factors regulating community were pH, ammonium and REEs, among which high concentration of REEs increased REEs‐dependent enzyme‐encoding genes (XoxF and ExaF/PedH). Additionally, we reconstructed 566 metagenome‐assembled genomes covering 70.4% of identifying indicators. Genome‐centric analysis revealed that the abundant archaea Thaumarchaeota and Xanthomonadaceae were often involved in nitrification and denitrification, while family Burkholderiaceae were capable of sulfide oxidation coupled with dissimilatory nitrate reduction to ammonium. These indicators play crucial roles in nitrogen and sulfur cycling as well as REEs immobilization in REEs‐AMD contaminated rivers. This study confirmed the potential dual effect of REEs on microbial community at the functional gene level. Our investigation on the ecological roles of indicators further provided new insights for the development of REEs‐AMD bioremediation.
Hyperaccumulator plants are the material basis for phytoextraction research and for practical applications in decontaminating polluted soils and industrial wastes. China’s high biodiversity and ...substantial mineral resources make it a global hotspot for hyperaccumulator plant species. Intensive screening efforts over the past 20 years by researchers working in China have led to the discovery of many different hyperaccumulators for a range of elements. In this review, we present the state of knowledge on all currently reported hyperaccumulator species from China, including Cardamine hupingshanensis (selenium, Se), Dicranopteris dichotoma (rare earth elements, REEs), Elsholtzia splendens (copper, Cu), Phytolacca americana (manganese, Mn), Pteris vittata (arsenic, As), Sedum alfredii, and Sedum plumbizincicola (cadmium/zinc, Cd/Zn). This review covers aspects of the ecophysiology and molecular biology of tolerance and hyperaccumulation for each element. The major scientific advances resulting from the study of hyperaccumulator plants in China are summarized and synthesized.
Mining activity for rare earth elements (REEs) has caused serious environmental pollution, particularly for soil ecosystems. However, the effects of REEs on soil microbiota are still poorly ...understood. In this study, soils were collected from abandoned sites of a REEs mine, and the structure, diversity, and co-occurrence patterns of soil microbiota were evaluated by Illumina high-throughput sequencing targeting 16S rRNA genes. Although microbiota developed significantly along with the natural restoration, the microbial structure on the site abandoned for 10 years still significantly differed from that on the unmined site. Potential plant growth promoting bacteria (PGPB) were identified by comparing 16S sequences against a self-constructed PGPB database via BLAST, and it was found that siderophore-producing and phosphorus-solubilizing bacteria were more abundant in the studied soils than in reference soils. Canonical correspondence analysis indicated that species richness of plant community was the prime factor affecting microbial structure, followed by limiting nutrients (total carbon and total nitrogen) and REEs content. Further co-occurring network analysis revealed nonrandom assembly patterns of microbiota in the studied soils. These results increase our understanding of microbial variation and assembly pattern during natural restoration in REE contaminated soils.
Due to their specific properties, ion-adsorption rare earth mine sites may be a threat for adjacent environments. This work was undertaken to assess whether former mining operations on ion-adsorption ...rare earth mine sites have a significant impact on water bodies and soils of the surrounding environments. Tailing soil materials, stream waters and sediments, and farmland soils were collected from one of the largest ion-adsorption rare earth mine sites worldwide (Southern China). Total concentrations of rare earth elements (REEs), Fe, Al, etc., and pH were measured. Results revealed high concentrations of REEs in tailing soils (392 mg kg−1), stream waters (4460 μg L−1), sediments (462 mg kg−1) and farmland soils (928 mg kg−1) in comparison with control sites. In the tailing profiles, light REEs (LREEs) were preferentially leached compared to middle REEs (MREEs) and heavy REEs (HREEs). Anomalies in tailings and stream water indicated strong soil weathering (Eu) and leaching activities (Ce) within the tailings. The MREE enriched pattern in stream water was more related to water parameters such as Al and Fe oxides, and ligands, than to the source of REEs. Anomalies also indicated that REEs contamination in the farmland soils was mainly originated from the stream water contaminated by the leaching from the tailings. In conclusion, a heavy REEs pollution was recorded in the surrounding environment of ion-adsorption rare earth mine. REEs fractionation, Ce and Eu anomalies provided an insight to the understanding of REEs leaching and soil weathering processes, and REEs environmental fate in rare earth mining area.
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•Heavy REEs contamination at ion-adsorption rare earth mine sites, especially stream waters and farmland soils.•Heavy soil weathering and leaching activities within the tailings in which LREEs were preferentially leached.•REEs fractionation and anomalies facilitate to understand REEs geochemistry within ion-adsorption rare earth mine sites.
To solve both the problems of P deficiency in arable soil and excessive waste sludge disposal, we evaluated hydrothermal carbonization of sludge with the aim of recycling sludge P resources for soil ...amendment. In contrast with pyrochars obtained through pyrolysis, hydrochars generated from hydrothermal carbonization often feature variable properties and therefore require detailed characterization. In this study, sludge‐derived hydrochars were evaluated to determine their P content and fractionation, release and availability of P, and P adsorption and desorption behavior. We also assessed changes in P availability after soil was amended with the hydrochars. Our results showed that the chars were rich in total P (up to 25,175 mg kg−1), but most of the free fractions were transformed to bound fractions, thereby reducing the available P concentrations. However, available P content was >417 mg kg−1, which was far higher than soil demand. The hydrochars shifted from releasing to adsorbing P adsorbent when the environmental P concentration increased above 20 mg L−1. The hydrochars showed a high phosphate adsorption capacity (up to 23,815 mg kg−1) and the adsorbed P could be readily released. The addition of 1% P‐laden hydrochar significantly enhanced the soil available P content by 8.93 mg kg−1. These findings have important implications for further development of hydrochar‐based P carriers as a slow‐releasing fertilizer.
Core Ideas
Charring transformed P from readily available fractions to moderately available ones.
Sludge‐derived hydrochars showed the best performance in long‐term P release.
Sludge‐derived hydrochars had better P retention capacity than their feedstock.
Applying the sludge‐derived hydrochar improved the available P content of soil.
The aim of this work is to numerically verify a new model of the rotating detonation engine (RDE) combustor. The new model, which we call the hollow combustor, has no inner wall and is hollow. It is ...presented to solve the problem of engine heating that arises in RDEs with the co-axial annular combustor. Using the one-step chemistry kinetic model and the Euler equations in cylindrical coordinates, a series of three-dimensional (3D) numerical simulations are performed to find out whether detonation waves can propagate in such combustors. The results show that this new RDE combustor model can realize energy conversion in rotating detonation. The fuel-based specific impulse can reach around 7000 s. By comparing the results of hollow and annular combustors, some important differences are observed though general behaviors in these two RDE combustor models are similar. One is that there is no repeated reflection of shock waves in the hollow model. Another is that in the center of the cylinder part of fresh gas rolls inward into the region r<Rinner and here the RDE experiences some non-detonation burning. Also, through the comparison and analysis, roles of the outer and inner walls are presented. Without the restriction of the inner wall, burnt gas flows a little more divergently.
The pollution of natural waters and sediments with metals derived from acid mine drainage (AMD) is a global environmental problem. However, the processes governing the transportation and ...transformation of AMD metals such as Cd in mountainous areas are poorly understood. In this study, the Cd isotopic composition and Cd concentration of river water and sediments (16 sampling sites) from an AMD-affected river in southern China were determined. Cd concentration in river water declined from its source at a tailings dam (304 μg L−1) to a point 14 km downstream (0.32 μg L−1). Sediment Cd concentration ranged from 0.18 to 39.9 μg g−1, suggesting that anthropogenic Cd is derived primarily from the tailing dam and easily enters the solid phase of the river. Isotopic data showed that the dissolved Cd in rivers was characterized by δ114/110Cd values ranging from 0.21‰ to 1.03‰, with a mean of 0.48‰. The greatest Cd isotope difference was observed between the water and sediments in the LW dam (Δ114/110Cdriver-sediment = 1.61‰, site 1), likely due to a rapid weathering dissolution of the ore tailings. In the river's upper reach (sites 2–3), isotope difference between river and sediment (Δ114/110Cdriver-sediment) ranged from 1.0‰ to 0.91‰. This suggests that a host of secondary processes might have impacted Cd isotope fractionation, including adsorption, ternary complexation and/or (co)precipitation of Cd on secondary oxides and hydroxides. In the middle and lower reaches, an abruptly elevated δ114/110Cd value near farmland (site 10) suggests the existence of a second Cd source. Based on the chemical properties of water samples we can attribute this heavy isotope signature to agricultural fertilizer and drainage from agricultural fields. Our results suggest that Cd isotope is a tracer for identifying and tracking Cd sources and attenuation mechanisms (adsorption/(co)precipitation) in a complex mountain watershed.
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•Mineral, tailings, sediments and AMD-contaminated river water were analyzed for Cd isotope ratios.•Distinctive Cd isotope signatures associated with transport and fate of riverine Cd.•Agricultural activities contributed a heavy isotope signature input of Cd.•Cadmium stable isotope is a promising tracer of attenuation processes in acid mine drainage.
Circular RNAs (circRNAs), which are single-stranded closed-loop RNA molecules lacking terminal 5' caps and 3' poly(A) tails, are attracting increasing scientific attention for their crucial ...regulatory roles in the occurrence and development of various diseases. With the rapid development of high-throughput sequencing technologies, increasing numbers of differentially expressed circRNAs have been identified in bladder cancer (BCa) via exploration of the expression profiles of BCa and normal tissues and cell lines. CircRNAs are critically involved in BCa biological behaviours, including cell proliferation, tumour growth suppression, cell cycle arrest, apoptosis, invasion, migration, metastasis, angiogenesis, and cisplatin chemoresistance. Most of the studied circRNAs in BCa regulate cancer biological behaviours via miRNA sponging regulatory mechanisms. CircRNAs have been reported to be significantly associated with many clinicopathologic characteristics of BCa, including tumour size, grade, differentiation, and stage; lymph node metastasis; tumour numbers; distant metastasis; invasion; and recurrence. Moreover, circRNA expression levels can be used to predict BCa patients' survival parameters, such as overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS). The abundance, conservation, stability, specificity and detectability of circRNAs render them potential diagnostic and prognostic biomarkers for BCa. Additionally, circRNAs play crucial regulatory roles upstream of various signalling pathways related to BCa carcinogenesis and progression, reflecting their potential as therapeutic targets for BCa. Herein, we briefly summarize the expression profiles, biological functions and mechanisms of circRNAs and the potential clinical applications of these molecules for BCa diagnosis, prognosis, and targeted therapy.
Recent studies suggest that perfluoroalkyl substances (PFAS) and PFAS alternatives can cross the placental barrier. However, little is known on the differential patterns of trans-placental transfer ...(TPT) among conventional PFAS and PFAS alternatives in epidemiological study.
We aimed to characterize comprehensive TPT patterns in conventional PFAS and PFAS alternatives using matched maternal-cord blood serum from a birth cohort.
A total of 424 mother-fetus pairs were recruited from the Maoming Birth Cohort during 2015–2018. We detected 20 PFAS in cord and maternal serum using an ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). TPT of PFAS was calculated via cord to maternal serum concentration ratios.
Both of PFOS alternatives (chlorinated polyfluorinated ether sulfonates, Cl-PFESAs) and PFOA short-chain alternative (perfluorobutanoic acid, PFBA) were widely detected in the cord and maternal serum. In cord serum, the predominant PFAS was PFOS (1.93 ng/mL), followed by PFBA (1.45 ng/mL), PFOA (0.75 ng/mL) and 6:2 Cl-PFESA (0.32 ng/mL). We found that the PFAS alternatives had higher TPT than PFOS and PFOA, such as PFBA vs. PFOA (median: 1.41 vs. 0.73, P < 0.001) and 8:2 Cl-PFESA vs. PFOS (median: 0.98 vs. 0.42, P < 0.001). Moreover, the TPT of 8:2 Cl-PFESA was higher than the precursor, linear and isomeric PFOS, respectively (P < 0.01). Furthermore, we found a U-shaped pattern for TPT in perfluorocarboxylic acid compounds (PFCAs) across different length of carbon chain.
Our findings suggest that PFAS alternatives may be more easily across the placenta than conventional PFAS. Given the widespread usage of PFAS alternatives, our results indicate that more research is needed to assess the potential health risks of prenatal exposure to PFAS alternatives in children.
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•Examined trans-placental transfer (TPT) of PFAS and the alternatives systematically•PFAS alternatives were widely detected in maternal and cord serum.•Higher TPT was observed in the PFAS alternatives than those in PFOS and PFOA.
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