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Despite their wide applications in soluble macromolecules, optical tweezers have rarely been used to characterize the dynamics of membrane proteins, mainly due to the lack of model membranes compatible with optical trapping. Here, we examined optical trapping and mechanical properties of two potential model membranes, giant and small unilamellar vesicles (GUVs and SUVs, respectively) for studies of membrane protein dynamics. We found that optical tweezers can stably trap GUVs containing iodixanol with controlled membrane tension. The trapped GUVs with high membrane tension can serve as a force sensor to accurately detect reversible folding of a DNA hairpin or membrane binding of synaptotagmin-1 C2AB domain attached to the GUV. We also observed that SUVs are rigid enough to resist large pulling forces and are suitable for detecting protein conformational changes induced by force. Our methodologies may facilitate single-molecule manipulation studies of membrane proteins using optical tweezers.

The cooling of the motor is one of key factors of keeping higher running efficiency of the refrigeration compressor. Suction refrigerant gas cooling motor is a widely used cooling method but it has poor cooling effect. A novel method of directly cooling screw compressor motor by thermosyphon refrigerant was proposed by authors. In this paper, the refrigeration system with thermosyphon refrigerant cooling motor (RSTRCM) and its basic principle were introduced firstly, then the mathematical model of energy and exergy of the system was built, and the test loop of an NH3/CO2 cascade refrigeration system was set up. Finally, compared with the refrigeration system with compressor suction gas cooling motor (RSCSCM), numerical analysis results showed that as condensation temperature of LTL is 5°C, RSTRCM can get higher exergy efficiency by up to 23.53%, and if condensing temperature of LTL increases from -5°C to 5°C, the power consumption of CO2 compressor and NH3 compressor in RSTRCM were reduced by 4.26% and 5.46% on average, separately. The test results showed that as the condensing temperature of the system is 40°C and the evaporation temperature is -45°C, -35°C, and -30°C, the coefficient of performance (COP) of RSTRCM were higher than that of RSCSCM by 10.42%, 6.61%, and 6.25%, respectively, which verify that the method of thermosyphon refrigerant cooling compressor motors can significantly improve the performance of the NH3/CO2 cascade refrigeration system.

The sluggish kinetics of Fe(Ⅱ) recovery in Fenton/Fenton-like reactions significantly limits the oxidation efficiency. In this study, we for the first time use boron carbide (BC) as a green and stable promotor to enhance the reaction of Fe(Ⅲ)/H2O2 for degradation of diverse organic pollutants. Electron paramagnetic resonance analysis and chemical quenching/capturing experiments demonstrate that hydroxyl radicals (•OH) are the primary reactive species in the BC/Fe(Ⅲ)/H2O2 system. In situ electrochemical analysis indicates that BC remarkably boosts the Fe(Ⅲ)/Fe(Ⅱ) redox cycles, where the adsorbed Fe(Ⅲ) cations were transformed to more active Fe(Ⅲ) species with a higher oxidative potential to react with H2O2 to produce Fe(Ⅱ). Thus, the recovery of Fe(Ⅱ) from Fe(Ⅲ) is facilitated over BC surface, which enhances •OH generation via Fenton reactions. Moreover, BC exhibits outstanding reusability and stability in successive cycles and avoids the secondary pollution caused by conventional organic and metalliferous promotors. Therefore, metal-free BC boosting Fe(Ⅲ)/H2O2 oxidation of organics provides a green and advanced strategy for water decontamination.

Outdoor lighting and other lighting systems can disrupt natural plant growth habits. Thus, LED lighting that is not detrimental to plant growth is required. In our study, Dy3+-doped Ca8ZnY(PO4)7:Dy3+ phosphor with enhanced luminescence properties caused by the co-dopants Mg2+ and B3+ were synthesised. The samples had multiple excitation peaks, indicating they are excited by either near-ultraviolet (n-UV) or blue chips. All samples exhibited bright narrow yellow and blue emission corresponding to the transitions of Dy3+ ions with 4F9/2→6H13/2 and 4F9/2→6H13/2, respectively. Moreover, doping with Mg2+ and B3+ enhanced the luminescence intensity, reaching 113.6 and 119.7%, respectively. In addition, the luminescence emission intensity at 150 °C was maintained at approximately 95% of the initial value at 25 °C, and its thermal stability increased by 123%. Devices assembled with an n-UV chip (388 nm) and the as-obtained CZMYP:Dy3+ phosphor emitted a bright warm white light and simulated outdoor dark lighting for tobacco cultivation, indicating that the as-prepared phosphor is an excellent candidate material for plant habitat-conscious phosphors.

Blue-violet light can not only enhance the total content of biomass and glucoside but also enrich the taste of the fruit. Thus, it is meaningful to study the blue-violet luminescent materials for plant cultivation. In this study, titanium (IV) -activated CaYAlO4 (CYAO) phosphors were synthesized by conventional high-temperature solid–state reaction. X-ray powder diffraction was employed to analyze the crystal-structure of CYAO. It is found that the doped Ti4+ ions do not change obviously the crystal structure of phosphors. Upon 246 nm excitation, CaYAl1-xO4:xTi4+ phosphors exhibit broad blue-violet emission band peaking at 395 nm, which can be attributed to the charge transfer of Ti4+–O2–. Moreover, this phosphor exhibits strong thermal stability. The luminescence emission intensity at 150 °C maintained about 91 mol% of its initial value at room temperature. Additionally, the electron transition process and concentration quenching mechanism of CaYAl1–xO4:xTi4+ are discussed in detail. The excellent luminescent properties indicate that CaYAl1-xO4:xTi4+ phosphor may have promising application in indoor plant cultivation.

This paper presents research on the economic damages from a hypothetical worst-case oil spill at the Straits of Mackinac between Lakes Huron and Michigan. This spill could occur because the Enbridge Line 5 oil pipeline traverses the Straits between Michigan's Upper and Lower Peninsula. We quantify potential economic damages to outdoor recreation, commercial fishing, shipping, residential properties, and energy and water supplies. Damages are estimated for two spill scenarios occurring at the onset of the summer tourism season with extensive shoreline oiling. Using evidence from past spills, economic damages would last for between one and two years and would affect locations on the periphery of the spill area, depending on the activity. We project the loss from the worst-case scenario would be at least $1.3 billion.

This study aimed to investigate the simultaneous removal of methylene blue (MB) and total dissolved copper (TCu) by heterogeneous zero-valent iron (ZVI) Fenton-like system (ZVI/H2O2) and elucidate the mechanism of synergistic effect for co-contaminants removal. Hydroxyl radical ( OH) formation was hypothesized to be the dominant pathway for the oxidation of MB, confirmed by the quenching experiments and ESR analysis. And the synergistic effect of TCu and ZVI greatly promoted the release of Fe2+, further accelerating the generation of hydroxyl radical ( OH) via Fenton reaction. The generation process of OH was unveiled by quenching experiments and electron spin resonance (ESR) analysis, while the processes of ZVI corrosion and TCu reduction were revealed through several characterization approaches including SEM, XRD, FTIR and XPS. The degradation pathway of MB was also investigated by LC-MS analysis. The MB initial concentration, TCu initial concentration, H2O2 dosage, ZVI dosage and initial solution pH could play crucial roles in the removal of MB and TCu. The influence of water matrix including inorganic anions (Cl−, NO3−, HCO3−) and actual water was finally conducted to elucidate the role of natural organic matter (NOM) in the environmental systems.

Air quality directly relates to human health and economic and social sustainable development. This study collected the meteorological data of Beijing from November 1, 2013 to October 31, 2017, employed vector autoregression (VAR) model, Granger causality test, impulse response function and variance decomposition to explore the dynamic effects of average humidity, extreme wind speed, sunshine duration, average wind speed and rainfall capacity on air quality index (AQI). The results indicated that the air pollution in Beijing was mainly a self-aggregation and self-diffusion process, the self-cumulative effect accounted for around 88.9318% during 5 periods, once the diffusion conditions of air pollution worsen, air pollution would be formed within 3 days. Meteorological conditions, especially extreme wind speed, sunshine duration and average humidity affected the concentration and spatial-temporal distribution of air pollutant. Extreme wind speed as atmospheric dynamic factor rather than average wind speed was the most important meteorological element influencing the AQI change in Beijing, which caused more atmospheric motion and turbulence, improving the diffusion and dilution ability of air pollutant, whose self-cumulative influence was around 7.5270% during 5 periods. Sunshine duration as atmospheric thermal factor was the secondary important meteorological element affecting AQI change in Beijing for it was associated with the formation of temperature stratification and inversion, the self-cumulative effect accounted for around 2.1402% during 4 periods. This study deepens the insights about the formation and diffusion mechanism of air pollution in Beijing, introduces nontraditional methods to review traditional issue and draw valuable conclusions. Other natural or human action factor should be further analyzed in the future research.

Graphical abstract, Highlights • Crystal structure of HLA-B*4001 was determined. • The salt bridges in HLA-B*4001 and H-2Kd have different structural characteristics. • MHC I mutations that disrupt the salt bridge alleviate peptide binding. • Mutations of the salt bridge-forming residues may impact TCR recognition, directly or indirectly., The viral peptides presentation by major histocompatibility complex class I (MHC I) molecules play a pivotal role in T-cell recognition and the subsequent virus clearance. This process is delicately adjusted by the variant residues of MHC I, especially the residues in the peptide binding groove (PBG). In a series of MHC I molecules, a salt bridge is formed above the N-terminus of the peptides. However, the potential impact of the salt bridge on peptide binding and T-cell receptor (TCR) recognition of MHC I, as well as the corresponding molecular basis, are still largely unknown. Herein, we determined the structures of HLA-B*4001 and H-2Kd in which two different types of salt bridges (Arg62-Glu163 or Arg66-Glu163) across the PBG were observed. Although the two salt bridges led to different conformation shifts of both the MHC I α helix and the peptides, binding of the peptides with the salt bridge residues was relatively conserved. Furthermore, through a series of in vitro and in vivo investigations, we found that MHC I mutations that disrupt the salt bridge alleviate peptide binding and can weaken the TCR recognition of MHC I-peptide complexes. Our study may provide key references for understanding MHC I-restricted peptide recognition by T-cells.

Rhodamine B (RhB) removal in a tungsten species-catalyzed Fenton-like system using nanoscale zero valent tungsten (nZVW) was investigated. The nZVW system can effective remove RhB in oxygenated water, and the nZVW/H2O2 system significantly enhances the RhB removal. Mechanism investigation shows that hydroxyl radical (·OH) is the primary reactive oxidant for removing RhB in both systems. The stepwise oxidation of nZVW can release reactive tungsten species and produce H2O2 by electron transfer from W0 or low valent tungsten species to O2, and ·OH was then formed via a Fenton-like reaction between low valent tungsten species and H2O2. The addition of H2O2 in the nZVW/H2O2 system can increase the RhB removal ratio by accelerating nZVW corrosion and enhancing the Fenton-like reaction. Moreover, higher pH inhibits the RhB removal due to the consumption of reactive tungsten species by OH−, and both higher nZVW and H2O2 dosages can enhance the RhB removal. RhB degradation pathways in the nZVW/H2O2 system are proposed involving N-de-ethylation, chromophore cleavage, ring open, and mineralization. In addition, the present study puts forward a new water treatment technique and contributes to understand the role of tungsten species in advanced oxidation processes.

Co/Bi25FeO40 was synthesized by a hydrothermal process and applied as a peroxymonosulfate (PMS) activator for the removal of Acid orange 7 (AO7). The morphology and physicochemical features of Co/Bi25FeO40 were obtained and analyzed via multiple characterizations. Crucial parameters including catalyst dosage, PMS concentration, temperature, pH and AO7 concentration were evaluated thoroughly for the kinetics performance. The results revealed that the efficient PMS activation performance was demonstrated using the synthesized Co/Bi25FeO40. Increasing catalyst dosage, PMS concentration, temperature and pH could promote AO7 removal, while the increase of AO7 concentration led to the inhibited degradation. Structural characterization, use of chemical probes and data of ESR analyses demonstrated that sulfate radicals and singlet oxygen (1O2) were identified as the major reactive oxygen species. Simultaneous pathways through radicals (sulfate radicals) and non-radical (singlet oxygen) were proposed with oxygen vacancy, active oxygen (O*) and the redox pair Bi5+/Bi3+ involved. This study could explore the application field of sillenite bismuth ferrite in non-photochemical application for environmental remediation.

This study aimed to elucidate the intrinsic mechanisms of PS activation by carbon nanotubes (CNTs). Singlet oxygen generation (1O2) and direct CNTs-mediated electron transfer were hypothesized to be two major pathways of the oxidation of 2,4-dichlorophenol (2,4-DCP) by PS in the presence of both unmodified and modified CNTs. For the first time, roles of CNT active sites responsible for PS activation were determined using CNT derivatization and structural characterization. By selectively deactivating the carbonyl, hydroxyl or carboxylic groups on CNTs surface and linear sweep voltammetry (LSV) analysis, CO groups were determined to be the main active sites contributing to the direct electron transfer oxidation, while singlet oxygen was generated at CNTs defects. Subsequent UV irradiation was shown to cause the recovery of surface defects with ID/IG of CNTs increasing by 21%. This resulted in the regeneration of the performance for the coupled system and allowed for multi-cycle activation of PS by CNTs. These results suggest that CNTs/PS system combined with regeneration based on UV irradiation can be used as an effective alternative process for continuous degradation of recalcitrant aqueous contaminants through the non-radical mechanism.

Graphitic carbon nitride (g-C3N4), as an attractive photocatalyst, has been extensively modified for enhancing its photocatalytic activity. In the present work, the electronic structure, carrier separation efficiency, band edges position, and optical property of g-C3N4 catalyst modified by five-membered heterocyclic small molecules as a ligand (thiophene, furan, pyrrole, or pyrryl) have been investigated by means of the Density Functional Theory (DFT) calculations. The results show that the carrier migration and separation efficiency as well as the utilization of visible light were enhanced after all four types of modifications. However, considering the relationship of overpotential of water redox reaction over g-C3N4 and band edge positions with respect to the water redox potentials, only adsorbing pyrrole can meet the requirements of the over-potential of the photoelectrochemical (PEC) splitting of water to generate H2 and O2. Due to the more activating n–π* electrons transitions in the distorted configurations, the optical absorption curves of the surface modified g-C3N4 systems are all red-shifted, while only the pyrrole modified system has two impurity energy levels, which indicates the rapid electron transit. Based on the above analysis, we propose that pyrrole should be an excellent ligand for the modification of g-C3N4 to improve the photocatalytic activity under visible light irradiation.

TiO2 has attracted widespread concern about its photo-catalysis in regard to water contaminant removal. However, TiO2 with different exposed facets shows considerable variation in adsorption and photo-catalysis performance. This study aims at comparatively investigating the adsorption and photo-catalysis performance of low-index {1 0 1}-TiO2, {0 0 1}-TiO2, {1 0 0}-TiO2 and high-index {2 0 1}-TiO2. The results showed that, compared to low-index TiO2, {2 0 1}-TiO2 exhibited a higher effectiveness on glyphosate (PMG) removal. In detail, the highest Langmuir adsorption capacity was observed on {2 0 1}-TiO2 (0.88, molecules/nm2). Based on 2D-COS and ATR-FTIR analysis, it is proved that the transformation sequence of each PMG functional group adsorbed on TiO2 followed different order. In addition, PMG photo-degradation on {2 0 1}-TiO2 had a higher apparent pseudo-first-order reaction constant (kapp = 3.0h−1) than other three TiO2. This is mainly attributed to a higher generation of reactive oxygen species (ROS), a larger electron transfer and oxygen reduction reaction (ORR) rate of {2 0 1}-TiO2, compared to other three TiO2, as investigated by ESR, photo-current and linear sweep voltammetry measurement, respectively. Furthermore, PMG photo-degradation on the four TiO2 was primarily due to OH. Thus, it can be reasonably inferred that the comparative investigation of high-index and low-index TiO2 can provide an integrated insight into similar adsorption and photo-catalysis behavior in the environment.

The oxidation capacity and mechanisms involved in activation of peroxomonosulfate (PMS) by nanoscale zero valent tungsten (nZVW) were investigated with dimethyl phthalate (DMP) as a targeted contaminant. DMP removal was completely achieved by hydroxyl radical ( OH) and sulfate radical ( SO4−) at 50 min in the nZVW/PMS system, and structural and componential changes of nZVW powder before and after reaction were not obvious. Low valence tungsten species were released during nZVW corrosion in oxygenated water via heterogeneous reactions, which was accelerated by PMS. The homogeneous reactions were mainly responsible for radical generation: 1) the stepwise oxidation of nZVW to produce H2O2, which was then activated by low valence tungsten species to generate OH; 2) the activation of PMS by low valence tungsten species to produce SO4− and OH. However, OH− reduced the reactivity of low valence tungsten species due to the formation of tungstate, higher pH thus partly inhibited the DMP removal. Two stages of DMP removal were found, and DMP degraded dramatically in the second stage. The degradation pathways of DMP were proposed, involving the formation of aromatic esters (monomethyl phthalate, methyl benzoate, and methyl salicylate), aromatic acids (phthalic acid, salicylic acid, and benzoic acid), and phenols (catechol, phenol, and hydroquinone) in turn. These results help to comprehend the application of nZVW in reactive radicals-based oxidation processes and the reactivity of low valence tungsten species in water treatment field.

Breast cancer is a common metastatic malignant tumor in women. Taurine has been found to have anti-tumor effects on a variety of cancers. However, to the best of our knowledge, the role of taurine in the metastasis of breast cancer has not been reported. Thus, this study examined the effects of taurine on the growth and lung metastasis of breast cancer. Furthermore, the metabolism of serum, tumor tissue, and lung metastasis tissue were studied in a 4T1 subcutaneously transplanted breast cancer model through the integration of a

Given that the novel coronavirus was detected in stool and urine from diagnosed patients, the potential risk of its transmission through the water environment might not be ignored. In the current study, to investigate the spread possibility of COVID-19 via the environmental media, three typical rivers (Yangtze, Han, and Fu River) and watershed cities in Hubei province of China were selected, and a more comprehensive risk assessment analysis method was built with a risk index proposed. Results showed that the risk index in the Yangtze River Basin is about 10−12, compared to 10−10 and 10−8 in the Han and Fu River Basins, and the risk index is gradually reduced from Wuhan city to the surrounding cities. The safety radius and safety time period for the Yangtze, Han, and Fu River are 8 km/14 h, 20 km/30 h and 36 km/36 h, respectively. The linear relationship between the risk potential calculated by the QMRA model and the multiple linear regression proved that the built index model is statistically significant. By comparing the theoretical removal rates for the novel coronavirus, our study proposed an effective method to estimate the potential spread risk of COVID-19 in the typical river basins., Graphical abstract Unlabelled Image, Highlights • Risk distribution and comparison of watershed cities of COVID-19 were identified. • Distribution order of risk index was Fu River > Han River > Yangtze River. • The safety radii of the three rivers were 8 km, 20 km and 36 km, respectively. • The safety periods of the three rivers were 14 h, 23 h and 36 h, respectively. • Modified QMRA index model was employed to assess the risk of COVID-19.

In order to accelerate the photo-Fenton reaction process of Fe(III) under visible light irradiation, BiOI was introduced into the Fe(III)/peroxydisulfate (PDS) system. The catalytic oxidation performance of vis-light/BiOI/Fe(III)/PDS system was evaluated using bisphenol AF (BPAF) as a representative organic contaminant. Within 30 min, nearly 100% of BPAF was degraded, proving that the system had an excellent ability to degrade organic pollutants in water. Free radical quenching experiments, electron spin resonance (ESR), and molecular probing experiments determined that the main reactive species in the system were hydroxyl radicals (

Background: : Sinopodophyllum hexandrum (S. hexandrum) is a typical Chinese herbal medicine with multiple components and pharmacological activities. However, the specific phytochemicals responsible for its anti-proliferative, anti-inflammatory and anti-viral effects remain unexplored. Purpose: : This study aimed to explore the specific bioactive phytochemicals from S. hexandrum responsible for its multiple remarkable pharmacological in an effort to construct and decipher its empirical therapeutic roles. Study design: : Bio-affinity ultrafiltration (AUF) with multiple drug targets corresponding to its empirical anti-proliferative, anti-inflammatory and anti-viral activities was developed to screen for potential bioactive ligands from S. hexandrum, and then in vitro bioactivity assays or molecular docking methods were used to verify those bioactive ligands. Methods: : The integrative analytical strategy was developed to rapidly screen and identify bioactive ligands from S. hexandrum. The in vitro anti-proliferative, COX-2 and ACE2 inhibitory assays of ligands were further verified by SRB cell proliferation and cytotoxicity detection, COX-2 and ACE2 inhibitor screening kits, respectively. Molecular docking analysis was also implemented by the AutoDockTools 1.5.6 software. Results: : Ten, seven, nine and nine phytochemicals were screened out and identified as the potential Topo I, Topo II, COX-2 and ACE2 ligands, respectively. Hereinto, podophyllotoxin and quercetin with higher EF values displayed strong inhibitory effects on A549 and HT-29 cells comparable with etoposide and 5-FU as the positive controls. Furthermore, compared with indomethacin at 0.73 ± 0.07 μM, kaempferol and podophyllotoxin with higher EF values exerted stronger inhibitory effects with IC50 values at 0.36 ± 0.02 μM and 10.49 ± 0.61 μM, respectively. Isorhamnetin with a higher EF value exerted stronger inhibitory effect against ACE2 with IC50 value at 118.46 ± 14.78 μM in contrast to podophyllotoxin with relatively lower EF value at > 970.00 μM. In addition, the optimal binding sites and mode of action between multiple drug targets and bioactive ligands were determined by molecular docking. Conclusion: : This study showcased a quick and reliable experimental strategy for unveiling the underlying mechanism of S. hexandrum, which could also provide valuable information for better understanding the therapeutic targets and ligands of other herbal medicines.

Advanced oxidation processes (AOPs) based on the metal–organic frameworks (MOFs) and peroxymonosulfate (PMS) have been demonstrated as promising methods for the degradation of contaminants. In this study, the degradation of bisphenol AF (BPAF) by activated PMS via amino-modified metal–organic frameworks (AMOF) was investigated thoroughly. BPAF could be efficiently removed (94.1%) in the optimal condition. The decontamination of BPAF could be accelerated significantly with the increasing temperature, and a highly stable degradation performance was observed at a wide pH range. Quenching experiments and electron paramagnetic resonance (EPR) tests revealed that sulfate radical (SO4–•), hydroxyl radical (HO•), singlet oxygen (1O2), and superoxide radical (O2–•) were produced synergistically in the AMOF/PMS system. Chloride ion (Cl–) exhibited a dual influence on BPAF removal, while other anions and NOM could hinder the degradation rate mildly. A total of fifty-two intermediates were identified using UHPLC-MS/MS method and four main degradation pathways were proposed based on the density functional theory (DFT) calculation, including the frontier molecular orbital theory (FMO), natural population analysis (NPA), and Fukui function. Finally, the Quantitative Structure Activity Relationship (QSAR) method for Toxicity Estimation Software Tool (TEST) was applied to estimate the accurate toxicity of BPAF and degradation byproducts. This study exhibited the promising potential for the decontamination of BPAF in the water via the AMOF based AOPs.

The operational issues of low-pressure ultrafiltration (UF) membrane are associated with its long-term membrane fouling caused by organic and inorganic matters, especially in treating shale gas wastewater (SGW) with complex water compositions. Herein, the effect of ferrate (Fe(VI)) pretreatment on UF membrane fouling and water quality in treating SGW was systematically investigated. Fe(VI) pretreatment significantly mitigated membrane fouling and slightly improved the effluent quality. The hydraulically irreversible fouling index and the total fouling index decreased by 69%–87% and 58%–84%, respectively. The mechanism of membrane fouling mitigation was comprehensively analyzed by the classical pore blocking model, correlation analysis between membrane fouling index and water quality, and the extended Derjaguin-Landau-Verwey-Overbeek theory. The synergistic mechanisms of membrane fouling mitigation were as follows: (i) Macromolecular organic matters (high molecular weight humics and biopolymers) which would block the membrane pores were oxidized into low fractions organics and removed by Fe(VI); (ii) Fe(VI) pretreatment improved interaction free energy of cohesion of foulants-foulants making foulants more hydrophilic and stable, and increased interaction free energy of adhesion of membrane-foulants making it more difficult for foulants to deposit on the membrane surface. Fe(VI) pretreatment had huge potential in alleviating membrane fouling in treating SGW and other complex wastewater.

Inoculation against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is ongoing worldwide. However, the emergence of SARS-CoV-2 variants could cause immune evasion. We developed a bivalent nanoparticle vaccine that displays the receptor binding domains (RBDs) of the D614G and B.1.351 strains. With a prime-boost or a single-dose strategy, this vaccine elicits a robust neutralizing antibody and full protection against infection with the authentic D614G or B.1.351 strain in human angiotensin-converting enzyme 2 transgene mice. Interestingly, 8 months after inoculation with the D614G-specific vaccine, a new boost with this bivalent vaccine potently elicits cross-neutralizing antibodies for SARS-CoV-2 variants in rhesus macaques. We suggest that the D614G/B.1.351 bivalent vaccine could be used as an initial single dose or a sequential enforcement dose to prevent infection with SARS-CoV-2 and its variants., Graphical abstract, Yuan et al. construct a bivalent vaccine based on the RBD sequence of two SARS-CoV-2 variants, D614G and B.1.351. Vaccination with a single dose or a prime-boost regimen is protective against SARS-CoV-2 challenge in mice. The bivalent vaccine elicits nAbs against SARS-CoV-2 variants in rhesus macaques with a third-dose regimen

Glyphosate (PMG) has been demonstrated to be strongly adsorbed on iron oxides, but few studies have been made on the subsequent degradation process. As the mechanism and process of PMG degradation plays a crucial role on its existence in the environment, this study aims to investigate the comparative adsorption and photo-degradation of PMG on goethite and magnetite. The results show that the Langmuir adsorption capacity of goethite (7.9 mg/g) was higher than that of magnetite (6.7 mg/g) at pH = 7. Further clarifying of Zeta potential and attenuated total reflectance Fourier-transform infrared spectroscopy measurements revealed that PMG was absorbed through the coordination of phosphonate moiety. In contrast, PMG degradation due to the photo-catalysis effectiveness of magnetite (kapp = 1.2 h−1) was significantly higher than that of goethite (kapp = 0.4 h−1) at pH = 7. This phenomenon was primarily due to the greater release of the dissolved iron in magnetite which led to the promotion of reactive oxygen species generation in the magnetite/UV system. DFT results show that the formation of Fe O P bonds in the presence of iron oxide would change the electron density distribution around the phosphorus center of PMG, and potentially made the C P bond more assailable to ROS. Furthermore, electron spin resonance results identified the existence of OH and O2 −, and further tests by adding radical captures proved the domination of OH in degrading PMG. In addition, intermediate identification of PMG revealed that amino acid, carboxyl acid and other inorganic ions were the main products in the process of photo-degradation. Therefore, it is concluded that the comparative exploration of goethite and magnetite on PMG degradation provides an integrated insight into the similar fate of PMG heterogeneous photo-degradation in the environment.

NASICON-type NaTi2(PO4)3 has been acknowledged as a promising anode for energy storage due to high ion conductivity and low cost. Nevertheless, intrinsic low electrical conductivity of NaTi2(PO4)3 and low stability in aqueous electrolyte limit its further applications in aqueous lithium rechargeable battery. In this paper, polyaniline as carbon and nitrogen sources was employed to synthesize nitrogen-doped carbon coated NaTi2(PO4)3 (NTP-P) composite by sol-gel approach and following calcination treatment. The loose and carbon-coated structure endows NTP-P with good structure stability and improved electrochemical kinetics. Compared with glucose-derived carbon-coated NaTi2(PO4)3 composite, NTP-P exhibits superior rate and cycling performance. NTP-P with proper carbon content delivers the discharge capacity of 119.4 and 83.4 mAh g−1 at rate of 0.2 and 15 C, and its capacity retention can maintain 85.8% after 1000 cycles at 5 C. This research reveals that the integration of carbon coating and nitrogen doping by using polyaniline give an excellent method to enhance the electrochemical properties of electrode materials.

2D MXenes have attracted extensive attentions owing to their anisotropy, high conductivity and other extraordinary properties. The popular preparation method of MXenes usually involves HF in high concentrations, which has seriously restricted their pervasive applications. In this work, a new hydrothermal route with low-toxicity etching agents (NaBF4, HCl) was used to synthesize Ti3C2 MXene (h-Ti3C2). Compared with the Ti3C2 prepared by the traditional HF etching method (t-Ti3C2), the h-Ti3C2 has the higher c lattice parameter, larger interlayer distance and larger BET specific surface area, because of the slow release mechanism during the hydrothermal process. The hydrothermal etching method not only avoided the use of high-concentration HF, but also was more efficient to prepare Ti3C2 flakes. Moreover, the hydrothermal etching route can be extended to other MXene materials, e.g. Nb2C. We demonstrated that the h-MXenes have better adsorption performance of methylene blue and methyl orange dyes. The hydrothermal etching route proposed in this study enabled the environmental benign and high efficiency exfoliation of MXenes, displaying the promise to facilely prepare 2D MXenes and paving a way to their widespread applications.

Sillenite bismuth ferrite (S-BFO) Bi25FeO40 was synthesized by a hydrothermal process and firstly adopted for the activation of peroxymonosulfate (PMS). Multiple characterization was conducted for the morphology and physicochemical features of S-BFO. Degradation of aquatic levofloxacin (LVF) was thoroughly evaluated by using a coupled process for the decontamination of the typical emerging organics. Some crucial parameters for the activation kinetics as well as economic recyclability were examined with the detailed mechanism proposed. For the first time, singlet oxygen (1O2) was identified as the main reactive oxygen species through radical scavenging experiments, electron paramagnetic resonance spectroscopy (EPR) and HPLC-MS determination. Based on the XPS and EPR results, a catalytic mechanism is proposed concerning the parallel generations of 1O2: (i) Bi5+ is replaced by Bi3+, resulting in the formation of an oxygen vacancy in the lattice and an active oxygen (O∗), which could produce 1O2 through the reactions with PMS; (ii) direct formation of 1O2 from radSO-5 generated by the interaction between Bi5+ and PMS. This study demonstrates a novel catalyst for heterogeneous activation of PMS via a non-radical mechanism, which could be alternatively adopted in the decontamination in surface/ground water.

Hydrophobic and dispersible functionalized reduced graphene oxide (FrGO) was employed to prepare chitosan gel droplets by crosslinking an inverse Pickering emulsion. The emulsion was prepared using toluene as the continuous phase and a chitosan aqueous solution as the dispersed phase. The effects of the FrGO concentration and the water/oil ratio on the chitosan droplet morphology were studied. At appropriate concentrations, the FrGO acted as a stabilizer and chitosan gel droplets were formed. Decreasing the FrGO concentration or increasing the water/oil ratio was unfavorable to the formation of chitosan droplets. Using this method, drug loaded chitosan gel droplets (microgels) were prepared and their release profiles as well as the factors that influence the drug release were investigated.