Resilience of fungal flora in bauxite residues amended with organic matter and vermiculite/fly ash.

The fungal community and soil geochemical, physical and biological parameters were analyzed, respectively, in bauxite residues (BRs) treated with organic matter and vermiculite/fly ash by phylogenetic analysis of ITS-18 S rRNA, community level physiological profiles (CLPP) and so on. The results indicated that after amendment of the BR, microbial utilization of carbohydrates and their enzyme activities were significantly increased, but fungal compositions at the phylum level were similar and dominated by the phylum of Ascomycota (82.05-98.96%, RA: relative abundance) after one year of incubation. The fungal taxa in the amended BR treatments, however, show significantly less alpha and beta diversity compared with the reference soils, although they still harbor a substantial novel taxon. The combined amendment of organic matter (OM) and vermiculite/fly ash significantly increases the fungal taxa at the genus and species level compared with solely OM amendment. The results of the following canonical correspondence analysis found that, over 90% variation of the fungal community could be explained by pH, OM and mean weight diameter (MWD) of aggregates; but the biological indicators, including urease (UR), dehydrogenase (DHA) and the value of average well color development (AWCD) could explain only 50% variation of the fungal flora in BRs. This paper indicated that resilience of fungal community in BRs was positively correlated with the BRs' improvement in fertility as well as biogeochemical properties, but alkalinity must be firstly decreased to the target level of BRs' rehabilitation.

Biochar-derived dissolved black carbon accelerates ferrihydrite microbial transformation and subsequent imidacloprid degradation.

The effects of an electron shuttle (dissolved black carbon (DBC) derived from biochar) on the microbial reduction of ferrihydrite and subsequent imidacloprid (IMI) degradation were studied. The results showed that DBC addition enhanced the microbial reduction of Fe(III) in ferrihydrite and increased the quantity of Fe(II) released into the liquid phase. The electron transfer capacity of DBC was significantly influenced by the content of redox-active oxygen-containing functional groups (e.g., quinone, hydroquinone, and polyphenol groups), which was dependent on the pyrolysis temperature. The electrochemical characteristics of DBC resulted in enhanced electron transfer, which promoted Fe(III) reduction and mediated the microbial transformation of ferrihydrite. The microbial transformation of ferrihydrite resulted in the formation of secondary minerals such as siderite and vivianite. The IMI degradation efficiency was related to the Fe(III) reduction rate and the pyrolysis temperature used in DBC production, and the degradation pathways were nitrate reduction and imino hydrolysis induced by the Fe(II) generated from the reduction of Fe(III) in ferrihydrite. The results obtained in this study provide new data for understanding the multifunctional roles of biochar-derived DBC in the redox and transformation processes of iron minerals induced by iron-reducing bacteria, the related biogeochemical cycles of iron and the fate of pollutants.

Biodistribution of 89Zr-oxine-labeled human bone marrow-derived mesenchymal stem cells by micro-PET/computed tomography imaging in Sprague-Dawley rats.

PURPOSE: To develop a method for labeling human bone marrow mesenchymal stem cells (hMSCs) with 89Zr-oxine to characterize the biodistribution characteristics of hMSCs in normal Sprague-Dawley (SD) rats in real-time by micro-PET-computed tomography (micro-PET/CT) imaging. METHODS: 89Zr-oxine complex was synthesized from 89Zr-oxalate and 8-hydroxyquinoline (oxine). After hMSCs were labeled with the 89Zr-oxine complex, the radioactivity retention, viability, proliferation, apoptosis, differentiation, morphology, and phenotype of labeled cells were assessed. The biodistribution of 89Zr-oxine-labeled hMSCs in SD rats was tracked in real-time by micro-PET/CT imaging. RESULTS: The cell labeling efficiency was 52.6 ± 0.01%, and 89Zr-oxine was stably retained in cells (66.7 ± 0.9% retention on 7 days after labeling). Compared with the unlabeled hMSCs, 89Zr-oxine labeling did not affect the biological characteristics of cells. Following intravenous administration in SD rats, labeled hMSCs mainly accumulated in the liver (7.35 ± 1.41% ID/g 10 days after labeling, n = 6) and spleen (8.48 ± 1.20% ID/g 10 days after labeling, n = 6), whereas intravenously injected 89Zr-oxalate mainly accumulated in the bone (4.47 ± 0.35% ID/g 10 days after labeling, n = 3). CONCLUSION: 89Zr-oxine labeling and micro-PET/CT imaging provide a useful and non-invasive method of assessing the biodistribution of cell therapy products in SD rats. The platform provides a foundation for us to further understand the mechanism of action and migration dynamics of cell therapy products.

Response of ammonia-oxidizing archaea and bacteria to sulfadiazine and copper and their interaction in black soils.

The large-scale development of animal husbandry and the wide agricultural application of livestock manure lead to more and more serious co-pollution of heavy metals and antibiotics in soil. In this study, two common feed additives, copper (Cu) and sulfadiazine (SDZ), were selected as target pollutants to evaluate the toxicity and interaction of antibiotics and heavy metals on ammonia oxidizers diversity, potential nitrification rate (PNR), and enzymatic activity in black soils. The results showed that soil enzyme activity was significantly inhibited by single Cu pollution, but the toxicity could be reduced by introducing low-concentration SDZ (5 mg · kg-1), which showed an antagonistic effect between Cu and SDZ (5 mg · kg-1), while the combined toxicity of high-concentration SDZ (10 mg · kg-1) and Cu were strengthened compared with the single Cu contamination on soil enzymes. In contrast, soil PNR was more sensitive to single Cu pollution and its combined pollution with SDZ than the enzyme activity. Real-time fluorescence quota PCR and Illumina Hiseq/Miseq sequencing results showed that ammonia-oxidizing archaea (AOA) was decreased in C2 (200 mg · kg-1 Cu treatment) and ammonia-oxidizing bacteria (AOB) was obviously stimulated in soil contaminated in C2, while in S5 (5 mg · kg-1 SDZ treatment), AOB was decreased; both AOA and AOB were significantly decreased at gene level in soils with combined pollutants (C2S5, 200 mg · kg-1 Cu combined with 5 mg · kg-1 SDZ). So, it can be concluded that combined pollution can cause more serious toxicity on the enzymatic activity, PNR, and ammonia-oxidizing microorganisms in soil through the synergistic effect between heavy metals and antibiotics pollutants.

Fast Lithium Ionic Conductivity in Complex Hydride-Sulfide Electrolytes by Double Anions Substitution.

Hydride-based solid-state electrolytes (SSEs) can maintain their stability against Li metal and exhibit high compatibility with a Li metal anode owing to their reducing property and flexible character. However, poor ionic conductivity at room temperature is a major challenge for hydride materials used as SSEs in a lithium ion battery. In this work, a room-temperature fast lithium-ion conductor is explored in response to double anion substitution, (100-x)(3LiBH4 -LiI)-xP2 S5 (LLPx, 0 ≤ x ≤ 50). Among these samples, LLP20 respectively delivers an ionic conductivity up to 3.77 × 10-4 S cm-1 at 30 °C and 1.0 × 10-2 S cm-1 at 100 °C, with a stable electrochemical window of 0-5 V. A Li plating/stripping test has been conducted under a current density of 1.0 mA cm-2 , which exhibits an excellent stability even after 1000 h. Moreover, the all solid-state cell exhibits a remarkable electrochemical performance in a wide temperature range including high reversible capacity, good rate capability, and long cycling durability. These outstanding performances present a practical strategy for developing ambient-temperature, fast ionic conductors for all solid-state batteries in near future.

Phototransformation of biochar-derived dissolved organic matter and the effects on photodegradation of imidacloprid in aqueous solution under ultraviolet light.

Dissolved organic matter (DOM) strongly influences the photodegradation of organic pollutants, varying depending on the structure of DOM. With the wide application of biochar, increasing amounts of DOM is released from biochar to the environment, which has different structural characteristics compared to natural DOM. In this study, DOM was derived from maize straw (MS) and pig manure (PM) and biochars by pyrolyzing MS and PM at 300 °C and 500 °C and the optical characteristics of DOM before and after phototransformation were explored via ultraviolet-visible spectroscopy and excitation-emission matrix fluorescence. Photodegradation of an insecticide, imidacloprid (IMI) in the presence of DOM was examined. The results showed that DOM derived from biochar obtained by pyrolyzing MS and PM mainly contained two identified fluorescent components and high pyrolysis temperature (500 °C) was associated with low molecular weight, small light-screening effects and great aromaticity of the DOM. After exposure to UV light, the aromaticity and molecular weight of the DOM declined due to phototransformation. Significant enhancement was observed in IMI photodegradation in the presence of biochar-derived DOM, and the enhancement was the greatest with DOM derived from pig manure biochar pyrolyzed at 500 °C. In addition to the light shielding effect, the 1O2 generated from DOM played an important role in the phototransformation of IMI and DOM. The loss of the nitro group and oxidation at the imidazolidine ring were the main photodegradation pathways for IMI. This study expands our understanding of the fate of biochar-derived DOM and its effects on the fate of coexisting organic pollutants.

Insight of soil amelioration process of bauxite residues amended with organic materials from different sources.

It aimed to investigate and evaluate the soil amelioration process of bauxite residues with the amendments of organic materials from different sources. Wheat straw, poultry manure compost, and biosolids were chosen as the added organic materials. A series of essential soil properties were analyzed to evaluate the effects of organic materials on the soil amelioration of bauxite residue. The results indicated that organic amendments could obviously improve the texture of bauxite residues by increasing large aggregates contents, and elevating its organic matter content and fertility level (such as TN and TP). At the same time, organic additions were effective in reducing bauxite residues' salinity as pH, electrical conductivity and sodium content were obviously decreased in all rehabilitated treatments in comparison with control treatment. These improvements created sufficient conditions for a quick recovery of microbial communities in bauxite residues matrix. The maximum microbial biomass C increased to 0.642 g-C·kg-1, and the activities of urease, catalase, and invertase were massively elevated, especially for those after a year of rehabilitation, although alkali-phosphatase was kept a less level compared with other biological parameters. The further principal analysis and cluster analysis indicated that after 1 year of organic amendment, the improved bauxite residues matrix was very close to the reference soil based on the measured soil microbial properties. All the results suggested that organic amendment is an effective way to stimulate the soil amelioration of bauxite residues, and among the three amended organic materials, wheat straw and biosolid were better in improving the abiotic environmental conditions as well as biotic function recovery in soil amelioration of bauxite residue.