Latest ArticlesRecent studies have proposed that the high-valent iron species (such as FeⅣO2+) rather than sulfate radical (SO4•−) and hydroxyl radical (•OH) are the main reactive oxidant species (ROS) in Fe(Ⅱ)/peroxydisulfate (PDS) system with the methyl phenyl sulfoxide (PMSO) as the FeⅣO2+ probe. However, many operational factors may interfere with the accuracy of this method, so the contribution of FeⅣO2+ calculated by this method is controversial. In this study, the possible effect of Fe(Ⅱ) concentration, pollutant type, reducing agent, or coexisted anions on FeⅣO2+ production and its corresponding contribution to the removal of target pollutants in the Fe(Ⅱ)/PDS system were investigated in detail, and the intrinsic mechanisms involved were also explored. This study shows that ROS generation is a complex process in the Fe(Ⅱ)/PDS system, and multiple combinatorial approaches are urgently required to deeply explore the contribution of ROS to the elimination of target contaminants.
Although SiO2-based anode is a strong competitor to supersede graphite anode for lithium-ion batteries, it still has problems such as low electrochemical activity, enormous loss of active lithium, and serious volume expansion. In order to solve these problems, we used a graphene network loaded with cobalt metal nanoparticles (rGO–Co) to coat SiO2 porous hollow spheres (SiO2@rGO–Co). The construction of porous hollow structure and graphene network can shorten the lithium-ion (Li+) diffusion distance and enhance the conductivity of the composite, which improves the electrochemical activity of SiO2 effectively. They also alleviate the volume expansion of the anode in the cycling process. Moreover, nano-scale cobalt metal particles dispersed on graphene catalyze the conversion reaction of SiO2 and activate the locked Li+ in Li2O through a reversible reaction, which improves the charge and discharge capacity of the anode. The capacity of SiO2@rGO–Co reaches 370.4 mAh/g after 100 cycles at 0.1 A/g, which is 6.19 times the capacity of pure SiO2 (59.8 mAh/g) under the same circumstance. What is more, its structure also exhibits excellent cycle stability, with a volume expansion rate of only 13.0% after 100 cycles at a current density of 0.1 A/g.
A series of α-MnO2 catalysts with various Mn valence states were treated by hydrogen reduction for different periods of time. Their catalytic capacity for formaldehyde (HCHO) oxidation was evaluated. The results indicated that hydrogen reduction dramatically improves the catalytic performance of α-MnO2 in HCHO oxidation. The α-MnO2 sample reduced by hydrogen for 2 h possessed superior activity and could completely oxidize 150 ppm HCHO to CO2 and H2O at 70 ℃. Multiple characterization results illustrated that hydrogen reduction contributed to the production of more oxygen vacancies. The oxygen vacancies on the catalyst surface enhanced the adsorption, activation and mobility of O2 molecules, and thereby enhanced HCHO catalytic oxidation. This study provides novel insight into the design of outstanding MnOx catalysts for HCHO oxidation at low temperature.
In this work, a series of chiral phenethylamine synergistic tricarboxylic acid modified β-cyclodextrin bonded stationary phase for high performance liquid chromatography (HPLC) were synthesized via a simple one-pot synthesis approach. Various racemates (aryl alcohols, flavanones, triazoles, benzoin, etc.) were well separated on the tricarboxylic acid modified chiral stationary phases in both normal and reversed modes with good reproducibility and stability, and the influence of mobile phase composition on resolution (Rs) were deeply investigated. The RSD values of Rs for repeatability and column-to-column were below 1.28% and 3.05%, respectively. Hence, the fabrication of tricarboxylic acid modified chiral stationary phase (CSPs) is a new efficient strategy to improve the application of β-cyclodextrin as CSPs in the field of chromatography.
Stimulus-responsive vesicles have broad applications in a variety of areas. Herein, oxidation-responsive framboidal triblock copolymer vesicles are prepared by photoinitiated RAFT seeded emulsion polymerization of a thioether-functionalized monomer using diblock copolymer vesicles as seeds. The obtained framboidal vesicles can transform into worms or spheres in the presence of reactive oxygen species, which can be further used for controlled release of cargos (e.g., silica nanoparticles).
A novel thiazolothiazole-bridged imidazole derivative (1) was found to exhibit blue fluorescence in gaseous state or in methanol and yellow fluorescence in solid state. The N-alkylation of imidazole subunit(s) in 1 using n-propyl iodide generated unsymmetrically or symmetrically alkylated thiazolothiazole-bridged imidazolium salts with good water solubility and remarkably strong emission in solution. Furthermore, the replacement of iodide counter-anion by triflate or bis(trifluoromethane sulfonyl)imide achieved remarkably strong emission in solid state and in solution as well as good water solubility. The strong fluorescence of dicationic salts with triflate and NTf2– counter-anions in solid state can be ascribed to their twisted and rigid structures induced by interionic C−H···F hydrogen bonding.
Achieving efficient degradation of organic pollutants via activation of sulfite is meaningful but challenging. Herein, we have constructed a heterogeneous catalyst system involving Co3O4 and TiO2 nanoparticles to form the p-n heterojunction (Co3O4/TiO2) to degrade acetaminophen (ACE) through photocatalytic activation of sulfite. Specifically, X-ray photoelectron spectroscopy analysis and theoretical calculations provide compelling evidence of electron transfer from Co3O4 to TiO2 at the heterointerface. The interfacial electron redistribution of Co3O4/TiO2 tunes the adsorption energy of HSO3‒/SO32‒ in sulfite activation process for enhanced the catalytic activity. Owing to its unique heterointerface, the degradation efficiency of ACE reached 96.78% within 10 min. The predominant active radicals were identified as •OH, h+, and SOx•− through radical quenching experiments and electron spin resonance capture. Besides, the possible degradation pathway was deduced by monitoring the generated intermediate products. Thereafter, the enhanced roles of well-engineered compositing interface in photocatalytic activation of sulfite for complete degradation of ACE were unveiled that it can improve light absorption ability, facilitate the generation of active species, and optimize reactive pathways. Considering that sulfite is a waste from flue gas desulfurization process, the photocatalytic activation of sulfite system will open up new avenues of beneficial use of air pollutants for the removal of pharmaceutical wastewater.
Cancer is the leading cause that threatens human life expectancy due to the lack of effective therapies. Cancer immunotherapy has been explored to improve the body's immune system against cancer and accompanied by promising results in recent years. Interleukin 15 (IL-15), a pleiotropic immunomodulator, is critical for immune cells development and displays great anti-tumor potential in both preclinical and clinical trials. In this study, superagonist IL-15 plasmid (psIL-15) consisting of IL-15Rα-sushi-linker-IL-15 was constructed in order to secret superagonist IL-15 (sIL-15) in tumor site. A gene delivery system through self-assembly by methylated polyethylene glycol-b-polylactic acid-b-methylated polyethylene glycol (mPEG-PLA-mPEG) and 1, 2-dioleoyl-3-trimethylammonium-propane (DOTAP), named DMAM, was designed to deliver psIL-15. Further study showed that DMAM/psIL-15 could successfully deliver psIL-15 to tumor cells and the supernatants of the tumor cells could further stimulate lymphocytes proliferation as well as activation in vitro. Local delivery of DMAM/psIL-15 in animal models demonstrated significant tumor inhibition through enhancing immune cells responses, reducing angiogenesis, promoting tumor cell apoptosis and inhibiting proliferation, with no evidence of system toxicities. These results indicate that DMAM/psIL-15 may be a promising strategy for cancer immunotherapy.
Versatile module design of precursor networks enables flexible functionalization of nano-carbon electrode materials to meet the adaptable energy-storage demand. Functionalized heterogeneous networks are more likely to decompose by swift temperature programming together with predesign module removal, so high functionality/network transfer from precursor to carbon is still a work in progress. A pre-stabilization route is proposed here to enhance the network strength at early pyrolysis and pin up precursor-level functionalities on the final carbon. Such strategy successfully fixes more electroactive N (4.28−8.86 wt%) into the resultant carbon microspheres compared with non-pretreated carbon (2.89 wt%), as well as achieves broad ion-accessible platforms of 1575–2269 m2/g with preset structural superiorities. As a result, a typical acidic device reveals an outstanding specific capacitance of 383 F/g at 10 mV/s. Taking advantage of a novel LiNO3-PAM polymer electrolyte, the upgraded symmetric device displays the maximum specific capacitance of 229 F/g, along with a boosted energy density of 41.1 Wh/kg at 643.4 W/kg. This work opens up a feasible insight into realizing highly efficient precursor/electrode design toward superior system with outstanding energy/power feature and temperature applicability.
Cell stress responses are associated with numerous diseases including diabetes, neurodegenerative diseases, and cancer. Several events occur under cell stress, in which, are protein expression and organelle-specific pH fluctuation. To understand the lysosomal pH variation under cell stress, a novel NIR ratiometric pH-responsive fluorescent probe (BLT) with lysosomes localization capability was developed. The quinoline ring of BLT combined with hydrogen ion which triggered the rearrangement of π electrons conjugated at low pH medium, meanwhile, the absorption and fluorescent spectra of BLT showed a red-shifts, which gived a ratiometric signal. Moreover, the probe BLT with a suitable pKa value has the potential to discern changes in lysosomal pH, either induced by heat stress or oxidative stress or acetaminophen-induced (APAP) injury stress. Importantly, this ratiometric fluorescent probe innovatively tracks pH changes in lysosome in APAP-induced liver injury in live cells, mice, and zebrafish. The probe BLT as a novel fluorescent probe possesses important value for exploring lysosomal-associated physiological varieties of drug-induced hepatotoxicity.