An outbreak of coronavirus disease 2019 (COVID-19)
, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
, has spread globally. Countermeasures are needed to treat and prevent ...further dissemination of the virus. Here we report the isolation of two specific human monoclonal antibodies (termed CA1 and CB6) from a patient convalescing from COVID-19. CA1 and CB6 demonstrated potent SARS-CoV-2-specific neutralization activity in vitro. In addition, CB6 inhibited infection with SARS-CoV-2 in rhesus monkeys in both prophylactic and treatment settings. We also performed structural studies, which revealed that CB6 recognizes an epitope that overlaps with angiotensin-converting enzyme 2 (ACE2)-binding sites in the SARS-CoV-2 receptor-binding domain, and thereby interferes with virus-receptor interactions by both steric hindrance and direct competition for interface residues. Our results suggest that CB6 deserves further study as a candidate for translation to the clinic.
Magnetic nanoparticles (MNPs) modified simultaneously with amorphous Fe and Mn oxides (Mag-Fe–Mn) were synthesized to remove arsenite As(III) from water. Mag-Fe–Mn particles were fabricated through ...heterogeneous nucleation technique by employing the maghemite as the magnetic core and Fe–Mn binary oxide (FMBO) as the coating materials. Powder X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy were utilized to characterize the hybrid material. With a saturation magnetization of 23.2 emu/g, Mag-Fe–Mn particles with size of 20–50 nm could be easily separated from solutions with a simple magnetic process in short time (within 5 min). At pH 7.0, 200 μg/L of As(III) could be easily decreased to below 10 μg/L by Mag-Fe–Mn particles (0.1 g/L) within 20 min. As(III) could be effectively removed by Mag-Fe–Mn particles at initial pH range from 4 to 8 and the residual As was completely oxidized to less toxic arsenate As(V). The co-occurring redox reactions between Mn oxide and As(III) was confirmed by XPS analysis. Chloride, sulfate, bicarbonate, and nitrate at common concentration range had negligible influence on As(III) removal, whereas, silicate and phosphate reduced the As(III) removal by competing with arsenic species for adsorption sites. As(III) removal was not obviously affected by natural organic matter (up to 8 mg/L as TOC). Mag-Fe–Mn could be regenerated with ternary solution of NaOH, NaCl, and NaClO. Throughout five consecutive cycles, the adsorption and desorption efficiencies maintained above 98% and 87%, respectively. Mag-Fe–Mn had a larger adsorption capacity for As(III) (47.76 mg/g) and could remove trace As(III) more thoroughly than MNPs modified solely with either Fe or Mn oxide due to the synergistic effect of the coating Fe and Mn oxides. This research extended the potential applicability of FMBO to a great extent and provided a convenient approach to efficiently remove trace As(III) from water.
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•MNPs were for the first time successfully modified with Fe–Mn binary oxide.•0.1 g/L Mag-Fe–Mn could lower As(III) from 200 to <10 μg/L at pH from 4 to 8.•Common coexisting anions and NOM had negligible influence on As(III) removal.•Adsorption and desorption maintained above 98% and 87% throughout 5 cyclic runs.•Mag-Fe–Mn was more effective for As(III) removal than either Mag-Fe or Mag-Mn.
In this study we reported that the presence of functionalized multi-walled carbon nanotubes (FCNT-H) would greatly enhance the degradation of atrazine (ATZ), a model contaminant, in the ...Fe(III)-mediated Fenton-like system. Efficient ATZ degradation (>90%) was achieved within 30 min in the presence of 20 mg.L−1 FCNT-H, 2.0 mg.L−1 Fe(III), and 170 mg.L−1 H2O2, whereas negligible ATZ degradation occurred in FCNT-H free system. The structure and surface chemistry of FCNT-H and other CNTs were well characterized. The formed active species were determined based on ESR analysis, and the mass balance of Fe species during the reaction was monitored. In particular, a new method based on ferrozine complexation was proposed to track the formed Fe(II). The results indicated that ATZ was mainly degraded by the generated hydroxyl radical (HO·), and Fe(III)/Fe(II) cycling was still the rate-limiting step. Besides a small fraction of Fe(III) reduced by FCNT-H, a new pathway was revealed for fast reduction of most Fe(III), i.e., reaction of FCNT-H-Fe(III) complexes with H2O2. Comparison of different CNTs-mediated Fe(III)/H2O2 systems indicated that such enhanced effect of CNTs mainly resulted from the surface carboxyl group instead of hydroxyl and carbonyl group. Combined with X-ray photoelectron spectroscopy (XPS) analysis, the electron density migration from Fe(III) to FCNT-H possibly resulted in the fast reduction of FCNT-H-Fe(III) complexes by H2O2. This study enables better understanding the enhanced Fe(III)-mediated Fenton-like reaction in the presence of MWCNTs and thus, will shed new light on how to develop more efficient similar Fenton systems via Fe(III) complexation.
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•Functionalized MWCNTs (20 mg.L−1) greatly enhanced atrazine degradation in Fe(III)/H2O2.•Trace level of Fe(III) (2.0 mg.L−1) was sufficient to initiate the Fenton-like process.•A new fast Fe(III)/Fe(II) cycling pathway was clearly verified.•Surface carboxyl groups played a key role in enhanced degradation.•Ferrozine was employed to selectively trap Fe(II) during the reaction.
A new composite catalyst, i.e., Fe doped g-C3N4/graphite (Fe-CN/G), was successfully constructed to activate peroxymonosulfate (PMS) for efficient phenolic compounds (i.e., p-chlorophenol, 4-CP) ...degradation in the pH range of 3–10. The optimized Fe-CN/G, i.e., Fe3.75-CN/G5.0, was fabricated at the dosage of 3.75 mmol FeCl3·6H2O, 5.0 g dicyandiamide, and 5.0 mmol glucose. Fe complexed in the nitrogen pots of Fe3.75-CN/G5.0 was demonstrated to be the primary active site for PMS activation, and the introduction of graphite favored the exposure of more accessible active sites in Fe3.75-CN/G5.0, suggesting a synergistic effect between the Fe and graphite of Fe3.75-CN/G5.0 on 4-CP degradation. Multiple experiments confirmed that sulfate radical (SO4−), hydroxyl radical (HO), singlet oxygen (1O2) and superoxide radical (O2−) exerted negligible contribution on 4-CP degradation. The in-situ Fe K-edge X-ray absorption near-edge structure (XANEX) analysis revealed a redox cycle of Fe in PMS/Fe3.75-CN/G5.0, suggesting the formation of high-valent iron-oxo species (FeIVO) was responsible for 4-CP degradation. In addition, PMS/Fe3.75-CN/G5.0 exhibited acceptable degradation of 4-CP in the presence of coexisting anions and natural organic matters (NOM). We believe this study provides new insights into the design and development of Fe-based heterogeneous catalysts for PMS-based wastewater treatment.
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•Fe(II) doped g-C3N4/graphite was facilely constructed for efficient PMS activation.•Fe(II) and graphite exhibited synergistic effect on the catalytic performance.•In-situ XANES spectra revealed the formation of FeIVO responsible for 4-CP degradation.•Satisfactory 4-CP degradation was achieved in the presence of inorganic anions and NOM.•The catalytic activity of the composite could be fully refreshed during cyclic runs.
•CHOS compounds were gradually decreased with the increasing of ozone dosage.•The complex reaction processes were deciphered based on 18 types of reactions.•Oxygenation reaction (+3O) possessed the ...largest number of precursor-product pairs.•Decyclopropyl and desulfonation were common reactions for CHON and CHOS compounds.•Spectral indexes had strong correlations with molecular-level parameters.
Ozonation is a well-recognized process in advanced treatment of municipal secondary effluent for water reclamation. However, the transformation of dissolved effluent organic matter (dEfOM) during ozonation of real effluents, particularly at molecular level, has been scarcely reported. In this study, we performed ozonation treatments on real secondary effluents from two municipal wastewater treatment plants, and used Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and various spectroscopic techniques to probe the transformation of dEfOM at four ozone dosage levels (0.28, 0.61, 0.89, and 1.21 mg O3/mg DOC). Most of the precursors were unsaturated and reduced compounds (positive double bond equivalent minus oxygen per carbon ((DBE−O)/C) and negative nominal oxidation state of carbon (NOSC)), whereas the products were mainly the saturated and oxidized ones (negative (DBE−O)/C and positive NOSC). As the ozone dosage increased, the relative abundance of O8–19 species gradually increased in the ozonated samples, whereas an opposite trend was observed for O5–7S1 species. Further, we employed 18 types of reactions to represent the ozonation process, and found that the oxygenation reaction (+3O) possessed the largest number of possible precursor-product pairs, and CHON compounds possessed the highest reactivity. Besides the dominant oxygenation reactions, decyclopropyl (−C3H4) was relatively common reaction for CHON compounds, while it was oxidative desulfonation (−SH2) for CHOS ones. In addition, the transformation of precursors to products accompanied with the drop of (DBE−O)/C, and the increase of NOSC and the O/C ratio. The precursors with aromaticity and fluorescence were mainly correlated with the compounds featuring higher (DBE−O)/C and lower NOSC values. This study is believed to help better understand and improve the application of ozonation process in advanced treatment of real wastewater.
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More and more studies have shown that circular RNAs (circRNAs) play a critical regulatory role in many cancers. However, the potential molecular mechanism of circRNAs in prostate cancer (PCa) remains ...largely unknown.
Differentially expressed circRNAs were identified by RNA sequencing. The expression of hsa_circ_0003258 was evaluated using quantitative real-time PCR and RNA in situ hybridization. The impacts of hsa_circ_0003258 on the metastasis of PCa cells were investigated by a series of in vitro and in vivo assays. Lastly, the underlying mechanism of hsa_circ_0003258 was revealed by Western blot, biotin-labeled RNA pulldown, RNA immunoprecipitation, luciferase assays and rescue experiments.
Increased expression of hsa_circ_0003258 was found in PCa tissues and was associated with advanced TNM stage and ISUP grade. Overexpression of hsa_circ_0003258 promoted PCa cell migration by inducing epithelial mesenchymal transformation (EMT) in vitro as well as tumor metastasis in vivo, while knockdown of hsa_circ_0003258 exerts the opposite effect. Mechanistically, hsa_circ_0003258 could elevate the expression of Rho GTPase activating protein 5 (ARHGAP5) via sponging miR-653-5p. In addition, hsa_circ_0003258 physically binds to insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3) in the cytoplasm and enhanced HDAC4 mRNA stability, in which it activates ERK signalling pathway, then triggers EMT programming and finally accelerates the metastasis of PCa.
Upregulation of hsa_circ_0003258 drives tumor progression through both hsa_circ_0003258/miR-653-5p/ARHGAP5 axis and hsa_circ_0003258/IGF2BP3 /HDAC4 axis. Hsa_circ_0003258 may act as a promising biomarker for metastasis of PCa and an attractive target for PCa intervention.
Selenium (Se) could enter the environment through different anthropogenic sources, posing potential health risk. The removal of trace Se(IV) from water by hematite coated magnetic nanoparticle ...(MNP@hematite) under different solution conditions was investigated through batch experiments. The adsorption capacity of Se(IV) by MNP@hematite was 25.0 mg/g.100 μg/L of Se(IV) could be rapidly decreased to below 10 μg/L by 0.1 g/L of MNP@hematite in 10 min. MNP@hematite could effectively remove Se(IV) in a wide pH range from 4 to 9. Se(IV) could form inner-sphere complex with MNP@hematite. Thus, the presence of chloride, nitrate, and sulfate (concentration of each anions <10 mM) did not affect the removal of Se(IV); whereas, carbonate (10 mM), silicate (1 mM), and phosphate (0.1 mM) yet reduced the adsorption efficiency by competing adsorption sites. Humic acid and alginate (up to 6 mg/L) did not have obviously influence on the removal of Se(IV). MNP@hematite particles were able to simultaneously remove Se(IV) and Sb(III) at trace level very efficiently in 10 min. The magnetic adsorbent can be easily recycled and regenerated in 10 mM NaOH for 15 min. In five consecutive cycles, the adsorption and desorption efficiencies were over 97% and 82%, respectively. MNP@hematite could be employed as effective adsorbent for Se(IV) removal from water.
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•0.1 g/L of MNP@hematite could reduce Se(IV) from 100 to < 10 μg/L within 10 min.•MNP@hematite could adsorb Se(IV) efficiently at pH from 4 to 9.•Common coexisting anions and NOM did not obviously affect Se(IV) removal.•MNP@hematite could remove Se(IV) and Sb(III) at trace level simultaneously.•MNP@hematite could be regenerated in NaOH solution and reused for Se(IV) removal.
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•Cr(VI) was efficiently reduced to Cr(III) at alkaline pHs by UV/sulfite process.•Common ions and organic matters interfered with Cr(VI) reduction slightly.•Spontaneous precipitation ...of Cr(III) occurred in the presence of Ca2+ (>2ppm).•eaq− was identified as the dominant reactive species in UV/sulfite process.
Chemical reduction of Cr(VI) to Cr(III) followed by Cr(III) precipitation is a widely employed strategy to mitigate Cr(VI) pollution from industrial effluents. Nevertheless, most of the available reduction processes are feasible at acidic pHs only, and very few technologies are capable of reducing Cr(VI) at alkaline pHs. Herein, we demonstrated that the UV/sulfite process is very promising for alkaline Cr(VI) remediation, including the Cr(VI) reduction to Cr(III) and simultaneous Cr(III) precipitation. In this process Cr(VI) reduction followed near zero-order kinetics, declining with an increase of pH (5–10) but boosting with increasing sulfite concentration. The co-existing Cl− and SO42− in water exerted negligible effect on Cr(VI) reduction, whereas the reduction kinetics was improved in the presence of citrate, EDTA or humic acid possibly due to their complexation with Cr(III). Similarly, the presence of borate buffer would significantly inhibit Cr(VI) reduction to Cr(III) as well as the final Cr(III) removal during precipitation. Fortunately, the presence of calcium ions even at trace level would favor Cr(III) precipitation and result in one-step removal of the total Cr at alkaline pH. The mechanism of Cr(VI) reduction was probed through irradiation manipulation and N2O addition, and the results suggested that excitation of sulfite is essential for alkaline Cr(VI) reduction, and eaq− is the dominant reactive species in the UV/sulfite process.
Hierarchies design of porosity in metal‐organic frameworks (MOFs) has gained significant interest in recent years, and customization of mesoporous sizes in MOFs is still quite challenging. Herein, a ...template‐free method by nucleation‐competition has been developed to realize a near‐linear control of the mesopore sizes (3–13 nm) in the hierarchical MOF UiO‐66(Hf). High selectivity of enzyme adsorption, high activity of bulky‐molecular catalysis, high stability of mesostructure, and extension to other MOFs further prove the success in the potential customization synthesis and applications.
A template‐free method by nucleation‐competition has been developed to realize near‐linear control of the mesopore sizes (3–13 nm) in the hierarchical metal‐organic frameworks UiO‐66(Hf), showing significant performances regarding molecular selectivity, catalytic activity, and mesostructure stability.
•Sb(III) adsorption capacity of MNP@hematite was twice that of commercial Fe3O4.•pH, ionic strength, coexisting anions and NOM did not inhibit Sb(III) removal.•MNP@hematite could remove trace Sb(III) ...and As(III) from water simultaneously.•Efficient removal of Sb(III) from real tap water was achieved.•MNP@hematite could be easily recycled with a magnet and could be used repeatedly.
Hematite coated magnetic nanoparticle (MNP@hematite) was fabricated through heterogeneous nucleation technique and used to remove trace Sb(III) from water. Powder X-ray diffraction, transmission electron microscopy (TEM), and alternating gradient magnetometry were utilized to characterize the prepared adsorbent. TEM image showed that MNP@hematite particles were spherical with size of 10–30nm. With saturation magnetization of 27.0emu/g, MNP@hematite particles could be easily separated from water with a simple magnetic process in short time (5min). At initial concentration of 110μg/L, Sb(III) was rapidly decreased to below 5μg/L by MNP@hematite in 10min. Sb(III) adsorption capacity of MNP@hematite was 36.7mg/g, which was almost twice that of commercial Fe3O4 nanoparticles. The removal of trace Sb(III) was not obviously affected by solution pH (over a wide range from 3 to 11), ionic strength (up to 100mM), coexisting anions (chloride, nitrate, sulfate, carbonate, silicate, and phosphate, up to 10mM) and natural organic matters (humic acid and alginate, up to 8mg/L as TOC). Moreover, MNP@hematite particles were able to remove Sb(III) and As(III) simultaneously. Trace Sb(III) could also be effectively removed from real tap water by MNP@hematite. The magnetic adsorbent could be recycled and used repeatedly.
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