Synergistic activation of smithsonite with copper-ammonium species for enhancing surface reactivity and xanthate adsorption

Copper ions(Cu^(2+))are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology.The adsorption of Cu^(2+)and xanthate on the sulfidized surface was investigated in various systems,and its effect on the surface hydrophobicity and flotation performance was revealed by multiple analytical methods and experiments.X-ray photoelectron spectroscopy(XPS)and time-of-flight secondary ion mass spectrometry(To F-SIMS)characterization demonstrated that the adsorption of Cu^(2+)on sulfidized smithsonite surfaces increased the active Cu—S content,regardless of treatment in any activation system.The sulfidized surface pretreated with NH_(4)^(+)-Cu^(2+)created favorable conditions for the adsorption of more Cu^(2+),significantly enhancing the smithsonite reactivity.Zeta potential determination,ultraviolet(UV)-visible spectroscopy,Fourier transform-infrared(FT-IR)measurements,and contact angle detection showed that xanthate was chemically adsorbed on the sulfidized surface,and its adsorption capacity in various systems was illustrated from qualitative and quantitative aspects.In comparison to the Na2S–Cu^(2+)and Cu^(2+)–Na2S–Cu^(2+)systems,xanthate exhibited a higher adsorption capacity on sulfidized smithsonite surfaces in NH_(4)^(+)-Cu^(2+)–Na2S–Cu^(2+)system.Hence,activation with Cu^(2+)–NH4+synergistic species prior to sulfidization significantly enhanced the mineral surface hydrophobicity,thereby increasing its flotation recovery.

Analysis of Calcined Red Mud Properties and Related Mortar Performances

Red mud(RM)is a low-activity industrial solid waste,and its utilization as a resource is currently a hot topic.In this study,the micro characteristics of red mud at different calcination temperatures were analyzed using X-ray diffraction and scanning electron microscopy.The performance of calcined red mud was determined through mortar strength tests.Results indicate that high-temperature calcination can change the mineral composition and microstructure of red mud,and increase the surface roughness and specific surface area.At the optimal temperature of 700°C,the addition of calcined red mud still leads to a decrease in mortar strength,but its activity index and flexural coefficient increase by 16.2%and 11.9%with respect to uncalcined red mud,reaching values of 0.826 and 0.974,respectively.Compared with the control group,the synergistic activation of calcined red mud with slag can increase the compressive and flexural strength of the mortar by 12.9%and 1.5%,reaching 8.7 and 62.4 MPa,respectively.Correspondingly,the activity index and flexural coefficient of the calcined RM and GGBS(Ground Granulated Blast furnace Slag)mixtures also increase to 1.015 and 1.130,respectively.

STING and TLR9 agonists synergistically enhance the immunogenicity of SARS-CoV-2 subunit vaccine

Vaccines that are reliable and efficacious are essential in the fight against the COVID-19 pandemic.In this study,we designed a dual-adjuvant system with two pathogen-associated molecular patterns(PAMPs),MnOx and CpG.This system can improve the retention of antigens at the injection site,facilitate pro-inflammatory cytokines secretion,further recruit and activate dendritic cells(DCs).As a result,antigens can be delivered to lymph nodes specifically,and adaptive immunity was strengthened.The immunized group showed an enhanced and broadened humoral and cellular immune response in systemic immunity and lung protection when combined with a tandem repeat-linked dimeric antigen version of the SARS-CoV-2 receptor binding domain(RBDdimer).Remarkably,even with a significant reduction in antigen dosage(three times lower)and a decrease in injection frequencies,our nanovaccine was able to produce the highest neutralizing antibody titers against various mutants.These titers were four-fold higher for the wild-type strain and two-fold higher for both the Beta and Omicron variants in comparison with those elicited by the Alum adjuvant group.In conclusion,our dual-adjuvant formulation presents a promising protein subunit-based candidate vaccine against SARS-CoV-2.

Combined antibacterial and antibiofilm activity of phenyllactic acid and bacteriocin XJS01 against Shigella flexneri

This study investigated antibacterial and antibiofilm activity of the combined use of phenyllactic acid(PLA)and bacteriocin XJS01 against Shigella flexneri_14.The minimum inhibitory concentration(MIC)of PLA and XJS01 against S.flexneri_14 was 2.45 mg/mL and 18.75μg/mL,respectively.Growth and kill kinetics assays showed that the combined use of 1/2MIC PLA plus 1/2MIC XJS01 had a better activity against planktonic S.flexneri_14 compared to treatment with PLA and XJS01 used singly(1/2MIC and 2MIC).Cellular biochemical and morphological analysis revealed the remarkable ability of the combination in disrupting cell appearance and promoting deformation of planktonic S.flexneri_14 compared to single use.Moreover,S.flexneri_14 biofilm formation was inhibited and degraded by the combination,which showed a more remarkable antibiofilm activity than PLA and XJS01 when used singly.This study demonstrates the synergistic antibacterial activity of PLA and XJS01 against S.flexneri_14 in either planktonic or biofilm states in foods.

STING and TLR7/8 agonists-based nanovaccines for synergistic antitumor immune activation

Immunostimulatory therapies based on pattern recognition receptors(PRRs)have emerged as an effective approach in the fight against cancer,with the ability to recruit tumor-specific lymphocytes in a low-immunogenicity tumor environment.The agonist cyclic dinucleotides(CDNs)of the stimulator of interferon gene(STING)are a group of very promising anticancer molecules that increase tumor immunogenicity by activating innate immunity.However,the tumor immune efficacy of CDNs is limited by several factors,including relatively narrow cytokine production,inefficient delivery to STING,and rapid clearance.In addition,a single adjuvant molecule is unable to elicit a broad cytokine response and thus cannot further amplify the anticancer effect.To address this problem,two or more agonist molecules are often used together to synergistically enhance immune efficacy.In this work,we found that a combination of the STING agonist CDGSF and the Toll-like receptor 7/8(TLR7/8)agonist 522 produced a broader cytokine response.Subsequently,we developed multicomponent nanovaccines(MCNVs)consisting of a PC7A polymer as a nanocarrier encapsulating the antigen OVA and adjuvant molecules.These MCNVs activate bone marrow-derived dendritic cells(BMDCs)to produce multiple proinflammatory factors that promote antigen cross-presentation to stimulate specific antitumor Tcell responses.In in vivo experiments,we observed that MCNVs triggered a strong T-cell response in tumor-infiltrating lymphocytes,resulting in significant tumor regression and,notably,a 100%survival rate in mice through 25 days without other partnering therapies.These data suggest that our nanovaccines have great potential to advance cancer immunotherapy with increased durability and potency.

Construction of highly stable selenium nanoparticles embedded in hollow nanofibers of polysaccharide and their antitumor activities

Nanotechnologies have been exploited to develop safe and effective medicines and pharmaceuticals.In the present study,a novel functional nanomedicine constructed from a bioactive polysaccharide and selenium nanoparficles （SeNPs） was developed.A highly-branched [3-（1→3）-D-glucan （AF1） with high anti-tumor activity was used to self-assemble hollow nanofibers with an apparent average diameter of 92 nm;Se nanopartides were synthesized via the reduction of sodium selenite.The results of light scattering,transmission electron microscopy,and X-ray diffraction demonstrated that the spherical SeNPs with a mean diameter of 46 nm were entrapped in the cavities of the AF1 hollow nanofibers through the formation of Se-O bonds between SeNPs and AF1,leading to the good dispersion and high stability in water for over 16 months.In vitro and in vivo assays indicated that the AF1-Se nanocomposite had higher anti-tumor activities against breast cancer.Furthermore,AF1-Se displayed a broad-spectrum inhibition against human cancers with low half maximal inhibitory concentration （IC50） values and low toxicity to normal cells.Particularly,the inhibition ratio of AF1-Se against MCF-7 cancer cells reached 75% at a concentration of 200 μg.mL-1 with 29 μM Se content,much higher than that by treatment with AF1 alone,suggesting a strong synergic effect and nano impact.Overall,we developed a method for increasing the stability,anti-tumor activity,and safety of SeNPs by wrapping with bioactive polysaccharides.