Photo‐mediation offers unparalleled spatiotemporal control over controlled radical polymerizations (CRP). Photo‐induced electron/energy transfer reversible addition–fragmentation chain transfer (PET‐RAFT) polymerization is particularly versatile owing to its oxygen tolerance and wide range of compatible photocatalysts. In recent years, broadband‐ and near‐infrared (NIR)‐mediated polymerizations have been of particular interest owing to their potential for solar‐driven chemistry and biomedical applications. In this work, we present the first example of a novel photocatalyst for both full broadband‐ and NIR‐mediated CRP in aqueous conditions. Well‐defined polymers were synthesized in water under blue, green, red, and NIR light irradiation. Exploiting the oxygen tolerant and aqueous nature of our system, we also report PET‐RAFT polymerization at the microliter scale in a mammalian cell culture medium.
Oxygen evolution reaction (OER) catalysts that function efficiently in pH‐neutral electrolyte are of interest for biohybrid fuel and chemical production. The low concentration of reactant in neutral electrolyte mandates that OER catalysts provide both the water adsorption and dissociation steps. Here it is shown, using density functional theory simulations, that the addition of hydrated metal cations into a Ni–Fe framework contributes water adsorption functionality proximate to the active sites. Hydration‐effect‐promoting (HEP) metal cations such as Mg2+ and hydration‐effect‐limiting Ba2+ into Ni–Fe frameworks using a room‐temperature sol–gel process are incorporated. The Ni–Fe–Mg catalysts exhibit an overpotential of 310 mV at 10 mA cm−2 in pH‐neutral electrolytes and thus outperform iridium oxide (IrO2) electrocatalyst by a margin of 40 mV. The catalysts are stable over 900 h of continuous operation. Experimental studies and computational simulations reveal that HEP catalysts favor the molecular adsorption of water and its dissociation in pH‐neutral electrolyte, indicating a strategy to enhance OER catalytic activity.
Background
Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) induces uncontrolled and self-amplified pulmonary inflammation, and has high morbidity and mortality rates in critically ill patients. In recent years, many bioactive ingredients extracted from herbs have been reported to effectively ameliorate ALI/ARDS via different mechanisms. Ferroptosis, categorized as regulated necrosis, is more immunogenic than apoptosis and contributes to the progression of ALI. In this study, we examined the impact of panaxydol (PX), isolated from the roots of Panax ginseng, on lipopolysaccharide (LPS)-induced ALI in mice.
Methods
In vivo, the role of PX on LPS-induced ALI in mice was tested by determination of LPS-induced pulmonary inflammation, pulmonary edema and ferroptosis. In vitro, BEAS-2B cells were used to investigate the molecular mechanisms by which PX functions via determination of inflammation, ferroptosis and their relationship.
Results
Administration of PX protected mice against LPS-induced ALI, including significantly ameliorated lung pathological changes, and decreased the extent of lung edema, inflammation, and ferroptosis. In vitro, PX inhibited LPS-induced ferroptosis and inflammation in bronchial epithelial cell line BEAS-2B cells. The relationship between ferroptosis and inflammation was investigated. The results showed that ferroptosis mediated inflammation in LPS-treated BEAS-2B cells, and PX might ameliorate LPS-induced inflammation via inhibiting ferroptosis. Meanwhile, PX could upregulate Keap1-Nrf2/HO-1 pathway, and selective inhibition of Keap1-Nrf2/HO-1 pathway significantly abolished the anti-ferroptotic and anti-inflammatory functions of PX in LPS-treated cells.
Conclusion
PX attenuates ferroptosis against LPS-induced ALI via Keap1-Nrf2/HO-1 pathway, and is a promising novel therapeutic candidate for ALI.
Ultrathin
metal–organic framework (MOF) nanosheets show
great potential in various separation applications. In this study,
MOF nanosheets are incorporated as a gutter layer in high-performance,
flexible thin-film composite membranes (TFCMs) for CO2 separation.
Ultrathin MOF nanosheets (∼3–4 nm) were prepared via a surfactant-assisted method and subsequently coated
onto a flexible porous support by vacuum filtration. This produced
an ultrathin (∼25 nm), extremely flat MOF layer, which serves
as a highly permeable gutter with reduced gas resistance when compared
with conventional polydimethylsiloxane gutter layers. Subsequent spin-coating
of the ultrathin MOF gutter layer with a polymeric selective layer
(Polyactive) afforded a TFCM exhibiting the best CO2 separation
performance yet reported for a flexible composite membrane (CO2 permeance of ∼2100 GPU with a CO2/N2 ideal selectivity of ∼30). Several unique MOF nanosheets
were examined as gutter layers, each differing with regard to structure
and thickness (∼10 and ∼80 nm), with results indicating
that flexibility in the ultrathin MOF layer is critical for optimized
membrane performance. The inclusion of ultrathin MOF nanosheets into
next-generation TFCMs has the potential for major improvements in
gas separation performance over current composite membrane designs.
Iridium (Ir)-based electrocatalysts are widely explored as benchmarks for acidic oxygen evolution reactions (OERs). However, further enhancing their catalytic activity remains challenging due to the difficulty in identifying active species and unfavorable architectures. In this work, we synthesized ultrathin Ir-IrO x /C nanosheets with ordered interlayer space for enhanced OER by a nanoconfined self-assembly strategy, employing block copolymer formed stable end-merged lamellar micelles. The interlayer distance of the prepared Ir-IrO x /C nanosheets was well controlled at ∼20 nm and Ir-IrO x nanoparticles (∼2 nm) were uniformly distributed within the nanosheets. Importantly, the fabricated Ir-IrO x /C electrocatalysts display one of the lowest overpotential (η) of 198 mV at 10 mA cm −2 geo during OER in an acid medium, benefiting from their features of mixed-valence states, rich electrophilic oxygen species (O (II-δ)− ), and favorable mesostructured architectures. Both experimental and computational results reveal that the mixed valence and O (II-δ)− moieties of the 2D mesoporous Ir-IrO x /C catalysts with a shortened Ir−O (II-δ)− bond (1.91 Å) is the key active species for the enhancement of OER by balancing the adsorption free energy of oxygen-containing intermediates. This strategy thus opens an avenue for designing high performance 2D ordered mesoporous electrocatalysts through a nanoconfined selfassembly strategy for water oxidation and beyond.
In the recent years, considerable progress has been made in iodine uptake—a radioactive emission process accompanying nuclear fission with porous organic polymers (POPs).
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