Search

Sunlight has long served as primary energy source on our planet, shaping the behavior of living organisms. Extensive research has been dedicated to unraveling the evolutionary pathways involved. When the formation of Earth atmosphere, it primarily consisted of small gas molecules, which are considered crucial for the emergence of life. Recent demonstrations have shown that these molecules can also be transformed into semiconductors, with the potential to harness solar energy and catalyze chemical reactions as photocatalysts. Building upon this research, this minireview focuses on the potential revolutionary impact of photocatalysis on Earth. Initially, it examines key reactions, such as the formation of prebiotic molecules and the oxygen evolution reaction via water oxidation. Additionally, various C−N complexes in photocatalysts are explored, showcasing their roles in catalyzing chemical reactions. The conclusion and outlook provide a potential pathway for the evolution of Earth, shedding light on the significance of metal‐free photocatalysts in development of Earth. [ABSTRACT FROM AUTHOR]

2-Aminoacetophenone is an off-flavor that can result from tryptophan degradation via riboflavin-photosensitized reaction. This study investigates the impact of light exposure, provided by a UV-C source, oxygen concentrations and transition metals on the formation of 2-aminoacetophenone in model wine containing tryptophan and riboflavin. Irrespective of oxygen and transition metals, >85% of tryptophan were degraded via first-order kinetics to unknown product(s). However, longer light exposure and more oxygen caused 2-aminoacetophenone concentrations to increase. Transition metals decelerated the 2-aminoacetophenone formation and acetaldehyde was formed suggesting photo-Fenton reaction occurred as a competitive reaction. The degradation rate of riboflavin inclined with less oxygen and in the presence of transition metals due to the depletion of oxygen by photo-Fenton reaction. Oxygen plays an important role in the regeneration of riboflavin and therefore must be seen as an intensifier for light-induced 2-aminoacetophenone formation. This paper provides new insights into riboflavin-photosensitized reactions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Cells have evolved intricate mechanisms for recognizing and responding to changes in oxygen (O 2 ) concentrations. Here, we have reprogrammed cellular hypoxia (low O 2 ) signaling via gas tunnel engineering of prolyl hydroxylase 2 (PHD2), a non-heme iron dependent O 2 sensor. Using computational modeling and protein engineering techniques, we identify a gas tunnel and critical residues therein that limit the flow of O 2 to PHD2's catalytic core. We show that systematic modification of these residues can open the constriction topology of PHD2's gas tunnel. Using kinetic stopped-flow measurements with NO as a surrogate diatomic gas, we demonstrate up to 3.5-fold enhancement in its association rate to the iron center of tunnel-engineered mutants. Our most effectively designed mutant displays 9-fold enhanced catalytic efficiency (k cat /K M =830±40 M -1  s -1 ) in hydroxylating a peptide mimic of hypoxia inducible transcription factor HIF-1α, as compared to WT PHD2 (k cat /K M =90±9 M -1  s -1 ). Furthermore, transfection of plasmids that express designed PHD2 mutants in HEK-293T mammalian cells reveal significant reduction of HIF-1α and downstream hypoxia response transcripts under hypoxic conditions of 1 % O 2 . Overall, these studies highlight activation of PHD2 as a new pathway to reprogram hypoxia responses and HIF signaling in cells., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Background: Time-Temperature Indicator (TTI) is an indicator device for real-time monitoring of the thermal history of the product. Due to the enzymatic reactions are affected by both time and temperature, enzymatic TTIs have been extensively studied and developed in recent years. However, enzymatic TTIs contain biologically active molecules (enzymes), which require high storage and use conditions. Most of them are designed to mix the system species together and irreversible reaction is undertaken. Nanozymes are the synthetic nanomaterials with similar biocatalytic functions as natural enzymes, which have extensive applications in analytical chemistry, biosensing, and environmental protection due to their facile synthesis, low cost, high stability and durability., Results: This work proposed to replace the natural laccase to laccase-like nanozyme, designed a novel and facile O 2 -activated time-temperature indicator for the first time. Nanozyme had excellent thermal and storage stability, which could maintain fabulous catalytic activity in the wide temperature range of 10-80 °C and after a long-term storage. Based on the O 2 was required to participate in the oxidation of laccase-catalyzed substrates, a squeeze-type O 2 -activated TTI was designed by controlling O 2 in the TTI system. The TTI was activated through extruding the O 2 -coated airbag ruptured and producing an irreversible color reaction. Combined with a smartphone to extract the chromaticity for portable visual real-time monitoring. Five sets of TTIs were prepared based on the concentration of nanozyme, and the activation energies (Ea) ranging from 28.45 to 72.85 kJ mol -1 , which were able to be fitted to products with Ea ranging from 3.45 to 97.8 kJ mol -1 and the monitoring-time of less than 7 days., Significance: Compared to the traditional enzymatic TTI, the TTIs designed based on nanozyme has the advantages of controlled activation, wider temperature monitor range and good stability. Providing a new approach to the development of real-time monitoring of smart devices., Competing Interests: Declaration of competing interest Our authors declare that no competing personal relationship or financial interests affecting this study reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Lytic polysaccharide monooxygenases (LPMOs) form a copper-dependent family of enzymes classified under the auxiliary activity (AA) superfamily. The LPMOs are known for their boosting of polysaccharide degradation through oxidation of the glycosidic bonds that link the monosaccharide subunits. This oxidation has been proposed to be dependent on either O 2 or H 2 O 2 as cosubstrate. Theoretical investigations have previously supported both mechanisms, although this contrasts with recent experiments. A possible explanation is that the theoretical results critically depend on how the Cu active site is modeled. This has also led to different results even when employing only H 2 O 2 as cosubstrate. In this paper, we investigate both the O 2 - and H 2 O 2 -driven pathways, employing Ls AA9 as the underlying LPMO and a theoretical model based on a quantum mechanics/molecular mechanics (QM/MM) framework. We ensure to consistently include all residues known to be important by using extensive QM regions of up to over 900 atoms. We also investigate several conformers that can partly explain the differences seen in previous studies. We find that the O 2 -driven reaction is unfeasible, in contrast with our previous QM/MM calculations with smaller QM regions. Meanwhile, the H 2 O 2 -driven pathway is feasible, showing that for Ls AA9, only H 2 O 2 is a viable cosubstrate as proposed experimentally.

Membrane technology holds great potential for separation applications and also finds critical needs in biomedical fields, such as blood oxygenation. However, the bottlenecks in gas permeation, plasma leakage, and especially hemocompatibility hamper the development of membrane oxygenation. It remains extremely challenging to design efficient membranes and elucidate underlying principles. In this study, we report biomimetic decoration of asymmetric nanoporous membranes by ultrathin Fe III -tannic acid metal-ligand networks to realize fast gas exchange with on plasma leakage and substantially enhance hemocompatibility. Because the intrinsic nanopores facilitate gas permeability and the Fe III -catechol layers enable superior hydrophilicity and electronegativity to original surfaces, the modified membranes exhibit high transport properties for gases and great resistances to protein adsorption, platelet activation, coagulation, thrombosis, and hemolysis. Molecular docking and density functional theory simulations indicate that more preferential adsorption of metal-ligand networks with water molecules than proteins is critical to anticoagulation. Moreover, benefiting from the better antiaging property gave by biomimetic decoration, the membranes after four-month aging present gas permeances similar to or even larger than those of pristine ones, despite the initial permeation decline. Importantly, for blood oxygenation, the designed membranes after aging show fast O 2 and CO 2 exchange processes with rates up to 28-17 and 97-47 mL m -2 min -1 , respectively, accompanied with no detectable thrombus and plasma leakage. We envisage that the biomimetic decoration of nanoporous membranes provide a feasible route to achieve great biocompatibility and transport capability for various applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Oxygenated volatile organic compounds (OVOCs) significantly modulate atmospheric chemistry, but the sources and air quality impacts of OVOCs in aged urban outflows remain to be elucidated. At a background site in South China, the ozone formation potential of six nonformaldehyde OVOCs studied was equivalent to that of 3.56 ppbv of formaldehyde, more than half of which was contributed by acetaldehyde. Source apportionment incorporating photochemical age revealed that considerable fractions (52.7%-62.6%) of the OVOCs were of biogenic origin, except for ethanol, which was primarily derived from anthropogenic emissions. The oxidation of cis -/ trans -2-butene explained 71.1% of the in situ acetaldehyde formation. In contrast, α/β-pinenes and isoprene contributed 73.8% and 28.4% to acetone and methylglyoxal formation, respectively. An average of 12.4% of net in situ ozone (O 3 ) production rate was attributed to the OVOCs studied, where the biogenic fractions accounted for 59%. The changes in the O 3 production rate and hydroxyl radical (OH) concentration caused by OVOCs were mainly affected by ozone formation sensitivity. The effects of primary acetaldehyde and acetaldehyde-led O 3 on secondary acetaldehyde formation were weak at this background site; however, they cannot be ignored in polluted areas. This study provides a scientific basis for mitigating O 3 pollution driven by biogenic emissions and OVOCs.

The colorimetric point-of-care test (POCT) offers a rapid and efficient method for detecting specific targets in real samples. However, traditional colorimetric methods often rely on complex signal amplification techniques or electronic devices to enhance detection sensitivity, which can inadvertently increase both cost and time, thus contradicting the fundamental goals of visual detection methods. Here, we presented a distance-based fluorescent immunosensor that utilized a gas-producing nanozyme for continuous gas production reaction as a signal. Specifically, the SOM-ZIF-8@Pt nanozyme catalyzed the production of O 2 from H 2 O 2 to cause an obvious increase in the pressure within a sealed chamber, thus driving the production of H 2 S to quench the fluorescence of CsPbBr 3 on the walls of the capillaries. Based on the competitive immunoassay, the fluorescence quenching lengths were relative with the concentration of aminopyrine in the range from 0.2 to 20 ng/L; thus, the fluorescent POCT-based homemade device was realized through the amplification of distance-based signals facilitated by the continuous gas production reaction. This strategy provides an effective way to realize POCT assays in resource-limited areas by transforming pressure variations into directly observable signals. Furthermore, distinguished by its high sensitivity, ease of operation, and portability, it also represents a significant advancement in biomedical diagnostics, particularly within home healthcare and clinical POCT.

A new biomimetic model complex of the active site of acireductone dioxygenase (ARD) was synthesized and crystallographically characterized ( [Ni( ii )( N -(ethyl- N 'Me 2 )(Py)(2- t -ButPhOH))(OTf)]- 1). 1 displays carbon-carbon oxidative cleavage activity in the presence of O 2 towards the substrate 2-hydroxyacetophenone. This reactivity was monitored via UV-Visible and NMR spectroscopy. We postulate that the reactivity of 1 with O 2 leads to the formation of a putative Ni(III)-superoxo transient species resulting from the direct activation of O 2 via the nickel center during the oxidative reaction. This proposed intermediate and reaction mechanism were studied in detail using DFT calculations. 1 and its substrate bound derivatives display reactivity toward mild outer sphere oxidants, suggesting ease of access to high valent Ni coordination complexes, consistent with our calculations. If confirmed, the direct activation of O 2 at a nickel center could have implications for the mechanism of action of ARD and other nickel-based dioxygenases and their respective non-traditional, enzymatic moonlighting functions, as well as contribute to a general understanding of direct oxidation of nickel(II) coordination complexes by O 2 .

High-molecular-weight (HMW) (>500 kDa) glutaraldehyde-polymerized human hemoglobin (PolyhHb) is a promising hemoglobin-based oxygen carrier (HBOC) due to its decreased risk of vasoconstriction and oxidative tissue injury. Previously, HMW tense (T) quaternary state PolyhHb was synthesized at the pilot scale with tangential flow filtration (TFF) for the removal of low-molecular-weight species. However, T-state PolyhHb is limited to specific biomedical applications due to its low oxygen affinity, thus motivating the need to produce high oxygen affinity relaxed (R) quaternary state PolyhHb at the pilot scale. This study explored the pilot-scale synthesis and extensive biophysical characterization of both HMW T- and R-state PolyhHb. The resultant characterization demonstrated the successful synthesis of low and high oxygen affinity PolyhHb with increased molecular weight (∼1000-1500 kDa). Overall, T- and R-state PolyhHb provides a platform for manufacturing oxygen therapeutics with a diverse range of oxygen affinities and potential biomedical applications.

Photodynamic therapy (PDT) has gained widespread acceptance as a clinical cancer treatment modality and has been attracting intensive attention on developing novel PDT strategies. However, the hypoxic environment in tumors is considered as a significant challenge for efficient type II PDT, based on the inference of the highly oxygen-concentration-related 1 O 2 generation. Contrary to this conventional understanding, our research demonstrates oxygen concentration independence in the photosensitized generation of 1 O 2 , as evidenced through steady-state and transient spectroscopy for chlorin e6 and methylene blue from normoxic to hypoxic conditions. We propose an oxygen-concentration-independent kinetic model, suggesting that efficient 1 O 2 generation can take place as long as the triplet-state lifetime ratio of the photosensitizer (τ h /τ n ) is in a similar range to pO 2 n /pO 2 h . Our findings provide insights into PDT mechanisms and indicate that the oxygen concentration reduction concerns may not be critical for effective PDT in hypoxic tumor environments.

Dioxygen (O 2 ) activation by iron-containing enzymes and biomimetic compounds generates iron-oxygen intermediates, such as iron-superoxo, -peroxo, -hydroperoxo, and -oxo, that mediate oxidative reactions in biological and abiological systems. Among the iron-oxygen intermediates, iron(III)-peroxo species are less frequently implicated as active intermediates in oxidation reactions. In this study, we present the combined experimental and theoretical investigations on cis -dihydroxylation reactions mediated by synthetic mononuclear nonheme iron-peroxo intermediates, demonstrating the importance of supporting ligands and metal centers in activating the peroxo ligand toward the O-O bond homolysis for the cis -dihydroxylation reactions. We found a significant ring size effect of the TMC ligand in [Fe III (O 2 )( n -TMC)] + (TMC = tetramethylated tetraazacycloalkane; n = 12, 13, and 14) on the cis -dihydroxylation reactivity order: [Fe III (O 2 )(12-TMC)] + > [Fe III (O 2 )(13-TMC)] + > [Fe III( O 2 )(14-TMC)] + . Additionally, we found that only [Fe III (O 2 )( n -TMC)] + , but not other metal-peroxo complexes such as [M III (O 2 )( n -TMC)] + (M = Mn, Co, and Ni), is reactive for the cis -dihydroxylation of olefins. Using density functional theory (DFT) calculations, we revealed that electron transfer from the Fe d xz orbital to the peroxo σ*(O-O) orbital facilitates the O-O bond homolysis, with the O-O bond cleavage barrier well correlated with the energy gap between the frontier molecular orbitals of d xz and σ*(O-O). Further computational studies showed that the reactivity of the synthetic [Fe III (O 2 )(12-TMC)] + complex is comparable to that of Rieske dioxygenases in cis -dihydroxylation, providing compelling evidence of the potential involvement of Fe(III)-peroxo species in Rieske dioxygenases. Thus, the present results significantly advance our understanding of the cis -dihydroxylation mechanisms by Rieske dioxygenases and synthetic nonheme iron-peroxo models.

Developing efficacious catalysts with superior Cl resistance and polychlorinated byproduct inhibition capability is crucial for realizing the environmentally friendly purification of chlorinated volatile organic compounds (CVOCs). Activating CVOC molecules and desorbing Cl species by modulating the metal-oxygen property is a promising strategy to fulfill these. Herein, a bifunctional CoRu/Al 2 O 3 catalyst with synergistic Co and Ru interactions (Ru-O-Co species) was rationally fabricated, which possesses abundant surface Co 2+ and Ru δ+ sites and collaboratively facilitates the activation of lattice oxygen (O 2- ) and molecular oxygen (O 2 → O 2- → O - ), accelerating 1,2-dichloroethane (1,2-DCE) decomposition via the reaction route of enolic species → aldehydes → carboxylate/carbonate. Furthermore, CoRu/Al 2 O 3 stimulates 1,2-DCE oxidation under humid conditions as H 2 O molecules can be easily activated to active *OH (potential oxidizing agent) over Ru species, accelerating C-Cl dissociation and Cl desorption and promoting the transformation of catecholate-type (C═O) species to easily oxidizable carboxylic acid (COOH) species, remarkably suppressing the formation of hazardous CCl 4 and CHCl 2 CH 2 Cl. This study provides critical insights into the development of bifunctional catalysts to synergistically activate surface oxygen species and H 2 O molecules for industrial CVOC stable and efficient elimination.

Group A streptococcus ( GAS ) is a pathogen typically transmitted through respiratory droplets and skin contact, causing an estimated 700 million mild non-invasive infections worldwide each year. There are approximately 650 000 infections that progress to severe invasive infections, even resulting in death. Therefore, the ability to detect GAS rapidly, accurately and in real time is important. Herein, we developed a nanozyme linked multi-array gas driven sensor (NLMAGS) to point-of-care testing of GAS within 2 h. The NLMAGS demonstrated excellent performance as it combined the advantages of nanozyme techniques, immunoassay techniques, and 3D printing techniques. Platinum- and palladium-rich nanozyme particles (Au@Pt@PdNPs) were synthesized and used to label monocloning antibodies as detection probes. Magnetic beads were labeled with monocloning antibodies as capture probes to establish a double-antibody sandwich immunoassay for the detection of GAS . The sandwich immune complex can catalyze the H 2 O 2 substrate and produce O 2 . GAS quantification can be achieved by measuring the distance that the O 2 pushes the ink drops forward in the sensor. Under optimized conditions, the NLMAGS quantitatively detected 24 spiked samples with a limit of detection (LOD) of 62 CFU mL -1 , which was 5 times lower than that of ELISA (334 CFU mL -1 ). A strong correlation with the conventional ELISA was found ( r = 0.99, P < 0.001). In comparison, the traditional lateral flow immunoassay based on Au@Pt@PdNPs-mAb2 (Au@Pt@PdNPs-LFIA) had a LOD of 10 4 CFU mL -1 , which was significantly higher than that of NLMAGS. The NLMAGS demonstrated excellent sensitivity to GAS . The intra- and inter-assay precisions of the sensor were below 15%. Overall, the established NLMAGS has promising potential as a rapid and quantitative method for detecting GAS and can also be used to detect various pathogens.

Purpose: Radiotherapy (RT) is currently recognized as an important treatment for glioblastoma (GBM), however, it is associated with several challenges. One of these challenges is the radioresistance caused by hypoxia, whereas the other is the low conversion efficiency of the strongly oxidized hydroxyl radical (•OH), which is produced by the decomposition of water due to high-energy X-ray radiation. These factors significantly limit the clinical effectiveness of radiotherapy., Results: To address these limitations, we developed a highly stable and efficient nanoplatform (MnO 2 /Pt@BSA). Compared to MnO 2 @BSA, this platform demonstrates high stability, a high yield of oxygen (O 2 ), enhanced production of •OH, and reduced clearance of •OH. The system exhibited increased O 2 production in vitro and significantly improved oxygen production efficiency within 100 s at the Pt loading of 38.7%. Furthermore, compared with MnO 2 , the expression rate of hypoxia-inducible factor (HIF-1α) in glioma cells treated with MnO 2 /Pt decreased by half. Additionally, the system promotes •OH generation and consumes glutathione (GSH), thereby inhibiting the clearance of •OH and enhancing its therapeutic effect. Moreover, the degradation of the nanoplatform produces Mn 2+ , which serves as a magnetic resonance imaging (MRI) contrast agent with a T 1 -weighted enhancement effect at the tumor site. The nanoplatform exhibited excellent biocompatibility and performed multiple functions related to radiotherapy, with simpler components. In U87 tumor bearing mice model, we utilized MnO 2 /Pt nanocatalysis to enhance the therapeutic effect of radiotherapy on GBM., Conclusion: This approach represents a novel and effective strategy for enhancing radiotherapy in gliomas, thereby advancing the field of catalytic radiotherapy and glioma treatment., Competing Interests: The authors report no conflicts of interest in this work., (© 2024 Chen et al.)

ZIF-67 was grown in situ on carbon cloth (CC) using a simple one-step method. The prepared ZIF-67/CC electrodes exhibited excellent CO 2 reduction reaction (CO 2 RR) performance in a dielectric barrier discharge plasma reactor. The highest concentrations of produced formic acid and formaldehyde were 9.16 and 0.068 mmol L -1 at a reaction time of 1 h, respectively. The high performance is related to the unique high aspect ratio structure and pad-like cavity of ZIF-67, which results not only in an increase in the specific surface area for CO 2 adsorption but also in the hydrophobicity of the electrode. Unexpectedly, the superoxide radical (·O 2 - ) greatly affects the reduction performance of the electrode. In addition, the ZIF-67/CC electrode maintained good CO 2 RR performance in the presence of different pollutants, and the production of formic acid and formaldehyde increased to 10.81 and 0.11 mmol L -1 at 1 h with the addition of 10 mg L -1 phenol. This research provides new directions in the field of plasma catalysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Photothermal catalytic oxidation is a promising and sustainable method for the degradation of indoor formaldehyde (HCHO). However, the excessively high surface temperature of existing photothermal catalysts during catalysis hinders the effective adsorption and degradation of formaldehyde under static conditions. Catalyst loading and oxygen vacancies (OVs) modulation are commonly employed strategies to reduce the photothermal catalytic temperature and enhance the efficiency of photothermal catalytic oxidation. In this work, a p-n type CuO/TiO 2 heterojunction is successfully loaded onto diatomite using a wet precipitation method. Under the irradiation of a 300W xenon lamp, the prepared composite material achieved a 100% removal rate of HCHO within 2 h, with a 98% conversion rate to CO 2 , surpassing the performance of both individual photocatalysts and thermocatalysts. Additionally, by adjusting conditions such as light irradiation and temperature, we have demonstrated that this material exhibits synergistic photothermal catalytic properties. Based on HRTEM, XPS, Raman, and EPR analyses, the introduction of diatomite as a catalyst support was shown to effectively increase the number of OVs. Experimental results, along with O 2 -TPD, photoelectrochemical characterization, and radical detection, demonstrate that the presence of OVs enhances the oxidative efficiency of both photocatalysis and thermocatalysis, as well as the UV-Vis-IR photothermal catalytic performance. The ternary composite material generates weak hydroxyl ( • OH) and superoxide ( • O 2 - ) radical under high-temperature with dark conditions, indicating its catalytic oxidation activity under this condition. The increase in temperature and the expansion of the spectral range both enhance the generation of these radicals. In summary, this work demonstrates that the use of diatomite as a support increases the material's specific surface area and OVs content, thereby enhancing adsorption and photothermal catalysis. It elucidates the enhanced catalytic degradation mechanism of this mineral-based photothermal catalyst., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Tobacco stalks, as one of the annual economic crops rich in biomacromolecules such as cellulose and hemicellulose, are more difficult to decompose into cellulose fibers due to their high degree of lignification compared to other ordinary straw feedstocks, resulting in their underutilization. In this study, we developed a mild three-stage alkali‑oxygen (AO) process to efficiently deconstruct the tobacco stalk cell walls. The process, involving alkaline dosages of 15 %, 10 %, and 3 % at each stage, effectively dissociated the cell walls and yielded cellulose fibers with high brightness (42.0 % ISO). The organics in the spent liquor, including lignin, hemicellulose, and small-molecular extracts, were isolated through acid/ethanol precipitation and organic solvent extraction. Lignin characterization by 2D HSQC NMR indicated that the majority of native β-aryl ether linkages were preserved after AO treatment, making it suitable for producing chemicals or biofuels via depolymerization. Additionally, the small-molecular extracts contained numerous depolymerized products from lignin and carbohydrates, as well as bioactive compounds derived from the tobacco stalk. Overall, this mild, efficient, and eco-friendly process offers a promising approach for the valorization of tobacco stalks and similar biomass resources., Competing Interests: Declaration of competing interest I declare that the authors have no competing interests as defined by Springer, or other interests that might be perceived to influence the results and/or discussion reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The establishment of S-scheme heterojunctions represents an effective strategy for enhancing the transfer and separation of charge carriers, thereby bolstering redox capacities and consequently benefiting subsequent photocatalytic reactions. In this study, the pristine Bi 7 O 9 I 3 underwent a facile vulcanization process to in-situ produce various composites. Systematical characterizations confirmed the simultaneous generation of Bi 7 O 9 I 3 /Bi 2 S 3 (BI-BS) heterojunctions with surface oxygen vacancies (OVs). Under visible light, these BI-BS composites exhibited improved NO removal efficiencies with reduced NO 2 generation compared to bare Bi 7 O 9 I 3 . Particularly, the best candidate BI-BS2 possesses the highest NO removal (43.02%) and lowest NO 2 generation (5.44%) among all tested samples. The improvement was primarily attributed to synergetic effects of heterojunction and surface OVs, including enhanced charge separation, heightened light responsiveness, and improved generation of reactive oxygen-containing species through an S-scheme mode. Furthermore, the Density Functional Theory (DFT) calculations had demonstrated that the establishment of BI-BS heterojunctions with surface OVs not only optimized the electronic structure to facilitate the transfer and separation of charge carriers, but also significantly enhanced the adsorption of NO, H 2 O, and O 2 molecules, ultimately favoring the generation of NO 3 - species. These as-synthesized composites indicated sufficient structural stability and hold potential for the photocatalytic removal of NO at ppb levels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The use of konjac glucomannan (KGM)/high acyl gellan gum (HAGG) edible film with single-sided unsaturated water swelling, designated as a water gradient film (WGF), has been shown to effectively enhance the preservation quality of frozen fish fillets. This study investigates the potential of using partially deacetylated konjac glucomannan (DKGM)/HAGG WGFs to enhance the preservation of frozen fish fillets. The partial deacetylation of KGM improved the water vapour and oxygen barrier properties of the frozen KGM/HAGG WGF, which exhibited a combination of film and ice structural characteristics. This improvement is attributed to strengthened interactions between DKGM and HAGG, resulting in a more structured film matrix that exhibited reduced permeability to both water vapour and oxygen. Furthermore, the improved interactions between DKGM and HAGG led to the formation of smaller polysaccharide ice crystals, which in turn increased the oxygen diffusion path along the intercrystalline boundaries, further decreasing oxygen permeability. Over a 90-day freezing period, the DKGM/HAGG WGF significantly outperformed traditional KGM/HAGG WGF, ice glazing, and polyethylene film packaging in preserving the quality of frozen fish fillets. This study provides a promising strategy for the design and development of DKGM-based WGFs for frozen fish fillet preservation applications., Competing Interests: Declaration of competing interest We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted. Neither the entire paper nor any part of its content has been published or has been accepted elsewhere. This submission for publication has been approved by all of the authors and by the institution where the work was carried out., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen peroxide (H 2 O 2 ), a versatile green compound, is increasingly in demand. The electrochemical two-electron oxygen reduction reaction (2e - ORR) is a simple and environmentally friendly substitute method to the traditional anthraquinone oxidation method for H 2 O 2 production. This study systematically investigates the 2e - ORR process on single transition metal atom-loaded boron fullerene (M - B 40 ) using density functional theory calculations. In evaluating the stability of the catalysts, we found that Au, Pd, Pt, Rh, and Ir atoms adsorbed on hexagonal or heptagonal sites of B 40 exhibit good stability. Among these, Pd-modified B 40 heptagonal cavity (Pd-B 40 -heptagonal) demonstrates an ideal Gibbs free energy change for OOH* (4.49 eV) and efficiently catalyzes H 2 O 2 production at a low overpotential (0.27 V). Electronic structure analysis reveals that electron transfer between Pd-B 40 -heptagonal and adsorbed O 2 facilitates O 2 activation. Additionally, the high 2e - ORR activity of Pd-B 40 -heptagonal is attributed to electron transfer from the Pd-d orbitals to the π* anti-bonding of p orbitals of OOH*, moderately activating the O-O bond. This study offers valuable understanding designing high-performance electrocatalysts for 2e - ORR., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Recently, chloroperoxidase (CPO)-mediated enzyme dynamic therapy (EDT) by mimicking the antipathogen function of neutrophils via generating highly active signet oxygen ( 1 O 2 ) has attracted great interest in biomedical applications. However, the therapeutic efficiency of EDT is largely restricted by the low CPO delivery efficiency and insufficient hydrogen peroxide (H 2 O 2 ) supply. In the present work, a neutrophil-mimicking nanozyme of MGBC with high CPO delivery efficiency, H 2 O 2 self-supply, and enzyme-cascade catalytic properties is designed for high-efficient treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. In the infection microenvironment, MGBC can effectively catalyze glucose to self-supply substantial H 2 O 2 , which enables long-lasting 1 O 2 generation via the CPO-mediated catalytic reaction. At the meantime, MGBC can also catalyze H 2 O 2 to sustainably release NO for gas therapy (GT), which synergistically strengthens the therapeutic effect of EDT. As a result, MGBC displayed effective MRSA-killing and MSRA biofilms-eradicating properties, and high efficiency in treating both MRSA infected full-thickness excision wounds and subcutaneous MRSA infection by exerting the synergistic bimodal EDT/GT therapeutic effects. In-depth mechanism study revealed that the synergistic EDT/GT antibacterial effects of MGBC can attenuate the drug resistance and toxicity of MRSA by significantly downregulating quorum sensing, multidrug efflux, virulence, and biofilm formation-related genes., (© 2024 Wiley‐VCH GmbH.)

In this study, a one-step solvothermal method was used to fabricate Fe 3+ doped BiOCl microflowers with abundant oxygen vacancies (OVs) in the presence of glacial acetic acid. Various analytical techniques were employed to characterize the structural, morphological, and optical properties of the prepared samples. The presence of OVs was confirmed by low temperature electron paramagnetic resonance (EPR) analysis. The photocatalytic results show that Fe 3+ doped BiOCl photocatalysts have higher activity than the bare BiOCl, and 10% Fe 3+ /BiOCl exhibits the highest photocatalytic performance, the photocatalytic efficiency of this sample is 2.3 and 1.1 times higher than that of the blank BiOCl toward photocatalytic degradation of perfluorooctanoic acid (PFOA) and rhodamine B (RhB), respectively. Furthermore, Fe 3+ doped BiOCl demonstrates excellent reusability. Based on the experimental observations, an enhancement mechanism for the photocatalytic activity of Fe 3+ doped BiOCl was reasonably elucidated.

Non-precious metal-based nitrogen-doped carbon (M-Nx/C) shows great potential as a substitute for precious metal Pt-based catalysts. However, the conventional pyrolytic methods for forming M-Nx/C active sites are prone to issues such as the lack of synergistic interactions among bimetallic atoms and the potential encasement of active sites, leading to compromised catalytic efficiency and hindered mass transfer. In this work, a highly active FeCo-N-C@U-AC electrocatalyst is developed with a high density of active sites, adequate exposure of catalytic sites, and robust mass transfer capability using the chemical vapor-phase deposition (CVD) technique. The resulting catalyst demonstrates impressive oxygen reduction reaction (ORR) catalytic performance and stability, with half-wave potentials of 0.820 V (0.1 M HClO 4 ) and 0.911 V (0.1 M KOH), respectively. It also exhibits significantly enhanced stability, retaining 93.25% and 98.38% of current after continuous 50 000 s of durability testing, surpassing the retention rates of Pt/C (80.31% in HClO 4 and 84.96% in KOH electrolytes). Notably, when employed as a cathode catalyst in proton exchange membrane fuel cells (PEMFCs) and zinc-air flow batteries (ZAFBs), the FeCo-N-C@U-AC catalyst delivers peak power densities of 859 and 162 mW·cm -2 , respectively, showcasing competitive performance comparable to benchmark Pt/C., (© 2024 Wiley‐VCH GmbH.)

The knowledge about co-transport of goethite and As 3+ to investigate the effect of goethite colloids on As 3+ transport under various degrees of seawater intrusion, particular extremely conditions, in groundwater environment is still limited. The main objective is to investigate the influence of seawater intrusion on the sorption, migration, and reaction of As 3+ and goethite colloids into sand aquifer media under anoxic conditions by using the bench-scale and reactive geochemical modeling. The research consisted of two parts as follows: 1) column transport experiments consisting of 8 columns, which were packed by using synthesis groundwater at IS of 0.5, 50, 200, and 400 mM referring to the saline of seawater system in the study area, and 2) reactive transport modeling, the mathematical model (HYDRUS-1D) was applied to describe the co-transport of As 3+ and goethite. Finally, to explain the interaction of goethite and As 3+ , the Derjaguin-Landau-Verwey-Overbeek (DLVO) calculation was considered to support the experimental results and HYDRUS-1D model. The results of column experiments showed goethite colloids can significantly inhibit the mobility of As 3+ under high IS conditions (>200 mM). The R f of As 3+ bound to goethite grows to higher sizes (47.5 and 65.0 μm for 200 and 400 mM, respectively) of goethite colloid, inhibiting As 3+ migration through the sand columns. In contrast, based on R f value, goethite colloids transport As 3+ more rapidly than a solution with a lower IS (0.5 and 50 mM). The knowledge gained from this study would help to better understand the mechanisms of As 3+ contamination in urbanized coastal groundwater aquifers and to assess the transport of As 3+ in groundwater, which is useful for groundwater management, including the optimum pumping rate and long-term monitoring of groundwater quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Cooking with active oxygen and solid alkali (CAOSA) is an efficient pretreatment method for biomass. For better grading of the lignin yellow liquor, the different lignin fractions and the recovered solid alkali were obtained using a simultaneous acid-alkali graded separation method. The results indicated that the recovery rate of solid alkali was 67.25 %, and the grading of lignin components was characterized by smaller dispersion coefficients, and more stable properties and structure. Lignin fractions with low dispersion coefficients possess more key structures, including the Phenol hydroxyl group (ArOH), Methoxy (OMe), and β-aryl ether (β-O-4), and have better thermal properties. The low molecular weight L4 has the highest ArOH content (2.1 mmol/g), which provides better antioxidant properties. The CAOSA process destroyed the S-unit and prevented lignin from condensation. Furthermore, the CAOSA process protected carbohydrates, which could effectively prevent them from dehydrating and re-polymerizing into pseudo-lignin. This allowed the pulp to remain natural, which was beneficial for subsequent transformation and utilization. Overall, the efficient separation of biomass components and lignin grading method proposed by combining the CAOSA process with the acid-alkali grading separation method has a strong application prospect and provides a theoretical basis for the high-value utilization of biomass and lignin., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Current views of O 2 accumulation in Earth history depict three phases: The onset of O 2 production by ∼2.4 billion years ago; 2 billion years of stasis at ∼1 % of modern atmospheric levels; and a rising phase, starting about 500 million years ago, in which oxygen eventually reached modern values. Purely geochemical mechanisms have been proposed to account for this tripartite time course of Earth oxygenation. In particular the second phase, the long period of stasis between the advent of O 2 and the late rise to modern levels, has posed a puzzle. Proposed solutions involve Earth processes (geochemical, ecosystem, day length). Here we suggest that Earth oxygenation was not determined by geochemical processes. Rather it resulted from emergent biological innovations associated with photosynthesis and the activity of only three enzymes: 1) The oxygen evolving complex of cyanobacteria that makes O 2 ; 2) Nitrogenase, with its inhibition by O 2 causing two billion years of oxygen level stasis; 3) Cellulose synthase of land plants, which caused mass deposition and burial of carbon, thus removing an oxygen sink and therefore increasing atmospheric O 2 . These three enzymes are endogenously produced by, and contained within, cells that have the capacity for exponential growth. The catalytic properties of these three enzymes paved the path of Earth's atmospheric oxygenation, requiring no help from Earth other than the provision of water, CO 2 , salts, colonizable habitats, and sunlight., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Bacterial cellulose (BC) is gathering increased attention due to its remarkable physico-chemical features. The high biocompatibility, hydrophilicity, and mechanical and thermal stability endorse BC as a suitable candidate for biomedical applications. Nonetheless, exploiting BC for tissue regeneration demands three-dimensional, intricately shaped implants, a highly ambitious endeavor. This challenge is addressed here by growing BC within a sacrificial viscoelastic medium consisting of an agarose gel cast inside polydimethylsiloxane (PDMS) molds imprinted with the features of the desired implant. BC produced with and without agarose has been compared through SEM, TGA, FTIR, and XRD, probing the mild impact of the agarose on the BC properties. As a first proof of concept, a PDMS mold shaped as a doll's ear was used to produce a BC perfect replica, even for the smallest features. The second trial comprised a doll face imprinted on a PDMS mold. In that case, the BC production included consecutive deactivation and activation of the aerial oxygen stream. The resulting BC face clone fitted perfectly and conformally with the template doll face, while its rheological properties were comparable to those of collagen. This streamlining concept conveys to the biosynthesized nanocelluloses broader opportunities for more advanced prosthetics and soft tissue engineering uses., Competing Interests: Declaration of competing interest The authors declare that they have no competing financial or personal interests that may influence the work reported in this study., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Polymer-metal complexes (PMCs) based on poly(2,2'-bipyridine-4,4'-dicarboxamide-co-polydimethylsiloxanes) with cyclometalated di(2-phenylpyridinato-C 2 ,N')iridium(III) fragments and cross-linked by Zn 2+ (Zn[Ir]-BipyPDMSs) or Ir 3+ (Ir[Ir]-BipyPDMSs) represent flexible, stretchable, phosphorescent, and self-healing molecular oxygen sensors. PMCs provide strong phosphorescence at λ em = 595-605 nm. Zn[Ir]-BipyPDMS with PDMS chain length of M n = 5000 has the highest quantum yield of 9.3% and is a molecular oxygen sensor at different O 2 concentrations (0-100 vol%) compared to Ir[Ir]-BipyPDMSs. A Stern-Volmer constant is determined for Zn[Ir]-BipyPDMS as K SV = 0.014% -1 , which is similar to the reported oxygen-sensitive iridium(III) complexes. All synthesized PMCs exhibit high elongation at break (up to 1100%) and self-healing efficiency (up to 99%)., (© 2024 Wiley‐VCH GmbH.)

Natural and artificial enzyme oxygen-generating systems for photodynamic therapy (PDT) are developed for tumor treatment, yet they have fallen short of the desired efficacy. Moreover, both the enzymes and photosensitizers usually need carriers for efficient delivery to tumor sites. Here, a self-cascade-enhanced multimodal tumor therapy is developed by ingeniously integrating self-cascade-enhanced PDT with Zn 2+ -overloading therapy. Manganese-porphyrin (TCPP-Mn) is chosen both as the photosensitizer and catalase (CAT) mimic, which can be encapsulated within glucose oxidase (GOx). Acid-responsive zeolitic imidazolate framework-8 (ZIF-8) is applied as the carrier for TCPP-Mn@GOx (T@G), attaining TCPP-Mn@GOx@ZIF-8 (T@G@Z). T@G@Z demonstrates robust anti-tumor ability as follows: upon the structural degradation of ZIF-8, GOx can mediate the oxidation of glucose and generate hydrogen peroxide (H 2 O 2 ); TCPP-Mn can catalyze H 2 O 2 into O 2 for self-cascade-enhanced PDT; meanwhile, the released Zn 2+ can enhance oxidative stress and induce mitochondrial dysfunction by destroying mitochondrial membrane potential; furthermore, immunotherapy can be activated to resist primary tumor and tumor metastasis. The self-cascade-enhanced T@G@Z exhibited its potential application for further tumor management., (© 2024 Wiley‐VCH GmbH.)

Immune checkpoint inhibitors (ICIs) offer promise in breaking through the treatment and survival dilemma of triple-negative breast cancer (TNBC), yet only immunomodulatory subtype and ≈5% TNBC patients respond as monotherapy due to lack of effector immune cells (internal problem) and physical barrier (external limitation) formed by cancer-associated fibroblasts (CAFs). A hydrogel drug-delivery platform, ALG@TBP-2/Pt(0)/nintedanib (ALG@TPN), is designed to induce strong immune functions and the dual elimination of the internal and external tumor microenvironment (TME). Activated by white light, through type I and II photodynamic therapy (PDT), TBP-2 generates large amounts of reactive oxygen species (ROS) intracellularly, oxidizing mitochondrial DNA (mtDNA). The unique catalase activity of Pt(0) converts endogenous H 2 O 2 to O 2 , reducing the anoxia-limiting PDT and enhancing ROS generation efficacy. Abundant ROS can oxidize Pt(0) to cytotoxic Pt(II), damaging the nuclear DNA (nDNA). Dual damage to mtDNA and nDNA might bi-directionally activate the cGAS/STING pathway and enhance the immune cell response. Besides, nintedanib demonstrates a significant inhibitory effect on CAFs, weakening the immune barrier and deepening immune cell infiltration. Overall, the study provides a self-oxygenating hydrogel with the "PDT/chemotherapy/anti-CAFs" effect, triggering the cGAS/STING pathway to reshape the TME. Both internal and external interventions increase anti-TNBC immune responses., (© 2024 Wiley‐VCH GmbH.)

Hypoxia inducible transcription factors (HIFs) mediate the hypoxic response in metazoans. When sufficient O 2 is present, Fe(II)/2-oxoglutarate (2OG)-dependent oxygenases (human PHD1-3) promote HIFα degradation via prolyl-hydroxylation. We report crystallographic, spectroscopic, and biochemical characterization of stable and inactive PHD2.Fe(III).2OG complexes. Aerobic incubation of PHD2 with Fe(II) and 2OG enables formation of PHD2.Fe(III).2OG complexes which bind HIF1-2α to give inactive PHD2.Fe(III).2OG.HIF1-2α complexes. The Fe(III) oxidation state in the inactive complexes was shown by EPR spectroscopy. L-Ascorbate hinders formation of the PHD2.Fe(III).2OG.(+/-HIFα) complexes and slowly regenerates them to give the catalytically active PHD2.Fe(II).2OG complex. Crystallographic comparison of the PHD2.Fe(III).2OG.HIF2α complex with the analogous anaerobic Fe(II) complex reveals near identical structures. Exposure of the anaerobic PHD2.Fe(II).2OG.HIF2α crystals to O 2 enables in crystallo hydroxylation. The resulting PHD2.product structure, manifests conformational changes compared to the substrate structures. The results have implications for the role of the PHDs in hypoxia sensing and open new opportunities for inhibition of the PHDs and other 2OG dependent oxygenases by promoting formation of stable Fe(III) complexes., (© 2024. The Author(s).)

This study compared the proteomics of beef patties under high‑oxygen modified atmosphere packaging (HiOx-MAP) and vacuum packaging (VP) during heating. The color and oxidation stability of fresh patties, and myoglobin denaturation of cooked patties were also measured. The results suggested that HiOx-MAP patties contained more oxymyoglobin in fresh meat and had higher myoglobin denaturation during heating than VP patties, resulting in premature browning (PMB) during cooking. Proteomic analysis found that the overabundance of proteasome subunit beta type-2 (PSMB2) and peroxiredoxin-2 (PRDX2) in HiOx-55 °C, which can remove the damaged proteins and inhibit oxidation respectively, are of benefit to meat color stability during storage, however, this was still insufficient to inhibit the occurrence of PMB during cooking. The high abundance of lamin B1 (LMNB1) in VP-55 °C can maintain the stability of meat color. This research provides greater understanding, based on proteomic perspectives, of the molecular mechanism of PMB., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective. To present and validate a method to simulate from first principles the effect of oxygen on radiation-induced double-strand breaks (DSBs) using the Monte Carlo Track-structure code TOPAS-nBio. Approach. Two chemical models based on the oxygen fixation hypothesis (OFH) were developed in TOPAS-nBio by considering an oxygen adduct state of DNA and creating a competition kinetic mechanism between oxygen and the radioprotective molecule WR-1065. We named these models 'simple' and 'detailed' due to the way they handle the hydrogen abstraction pathways. We used the simple model to obtain additional information for the •OH-DNA hydrogen abstraction pathway probability for the detailed model. These models were calibrated and compared with published experimental data of linear and supercoiling fractions obtained with R6K plasmids, suspended in dioxane as a hydroxyl scavenger, and irradiated with 137 Cs gamma-rays. The reaction rates for WR-1065 and O 2 with DNA were taken from experimental works. Single-Strand Breaks (SSBs) and DSBs as a function of the dose for a range of oxygen concentrations [O 2 ] (0.021%-21%) were obtained. Finally, the hypoxia reduction factor (HRF) was obtained from DSBs. Main Results. Validation results followed the trend of the experimental within 12% for the supercoiled and linear plasmid fractions for both models. The HRF agreed with measurements obtained with 137 Cs and 200-280 kVp x-ray within experimental uncertainties. However, the HRF at an oxygen concentration of 2.1% overestimated experimental results by a factor of 1.7 ± 0.1. Increasing the concentration of WR-1065 from 1 mM to 10-100 mM resulted in a HRF difference of 0.01, within the 8% statistical uncertainty between TOPAS-nBio and experimental data. This highlights the possibility of using these chemical models to recreate experimental HRF results. Significance. Results support the OFH as a leading cause of oxygen radio-sensitization effects given a competition between oxygen and chemical DNA repair molecules like WR-1065., (© 2024 Institute of Physics and Engineering in Medicine. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Optode-based chemical imaging is a rapidly evolving field that has substantially enhanced our understanding of the role of microenvironments and chemical gradients in biogeochemistry, microbial ecology, and biomedical sciences. Progress in sensor chemistry has resulted in a broadened spectrum of analytes, alongside enhancements in sensor performance (e.g., sensitivity, brightness, and photostability). However, existing imaging techniques are often costly, challenging to implement, and limited in their recording speed. Here we use the "frame-straddling" technique, originally developed for particle image velocimetry for imaging the O 2 -dependent, integrated luminescence decay of optical O 2 sensor materials. The method synchronizes short excitation pulses and camera exposures to capture two frames at varying brightness, where the first excitation pulse occurs at the end of the exposure of the first frame and the second excitation pulse at the beginning of the second frame. Here the first frame truncates the luminescence decay, whereas the second frame fully captures it. The difference between the frames quantifies the integral of the luminescence decay curve, which is proportional to the luminescence lifetime, at time scales below one millisecond. Short excitation pulses avoid depopulation of the ground state of luminophores, resulting in a linear Stern-Volmer response with increasing concentrations of the quencher (O 2 ), which can be predicted through a simple model. This methodology is compatible with a wide range of camera systems, making it a versatile tool for various optode based chemical imaging applications. We showcase the utility of frame straddling in measuring O 2 dynamics around algae and by observing O 2 scavenging sodium dithionite particles sinking through oxygenated water.

Detecting hydrogen sulfide (H 2 S) odor gas in the environment at parts-per-billion-level concentrations is crucial. However, a significant challenge is the rapid deactivation caused by SO 4 2- deposition. To address this issue, we developed a sensing material comprising Fe 2 O 3 -decorated WO 3 nanowires (FWO) with strong interfacial interaction. During the H 2 S sensing process, important oxygen vacancies (OVs) are generated in situ and are recyclable on the surface of the Fe 2 O 3 cluster. This sensor achieves a response of 140 (Ra/Rg) toward 50 ppm of H 2 S at 250 °C, with an experimentally measured detection limit of 1 ppb. It also exhibits remarkable stability, with no significant change observed over a long period of 150 days. Based on a combination of in situ DRIFT and DFT calculations, we have identified that the overactivation of O 2 is the key step in the formation of SO 4 2- . This overactivation can be partially modulated by the synergistic effect of Fe 2 O 3 decoration and the in situ generated OVs, regulating the oxidation product to SO 2 rather than the toxic SO 4 2- . Furthermore, the continuous generation of OVs compensates for the loss of active sites pertaining to SO 4 2- deposition, thereby contributing to the excellent stability of the sensor. This study underscores the beneficial impact of in situ OV generation in FWO for H 2 S sensing, offering a dynamic strategy to enhance sensor performance, particularly in terms of stability.

Pd-modified metal sulfide gas sensors exhibit excellent hydrogen (H 2 ) sensing activity through spillover effects. However, the emulative oxygen adsorption often occupies an exposed Pd surface and thus limits the effective Pd-H interaction, impeding the H 2 sensing performance in air. Herein, we develop an edge-rich Pt-shell/Pd-core structure to adjust the selective adsorption between oxygen and hydrogen for effective H 2 sensing in an air atmosphere. Detailedly, through accurately regulating the rate of Pt deposition onto the icosahedron Pd surface, an edge-rich Pt-shell/Pd-core structure can be first achieved. It has been found that marginal Pt aggregations can segregate the oxygen molecules around the Pt species and induce easier Pt-O bonding, further guiding accessible Pd surfaces for effective Pd-H interactions, which can be verified by 1 H ssNMR, in-situ Raman, ex-situ XPS, and density functional theory analyses. The final ZnS/PdPt sensor exhibits an ultrasensitive response (8608 to 4% H 2 ) and a wide detected range (0.5 ppm-4%) in air, exceeding most reported hydrogen sensors.

Ratiometric probing of analytes presents a substantial advancement in molecular recognition, offering self-calibrating signals that enhance the measurement accuracy and reliability. We present a dual-emitting probe based on (6,5) chirality-enriched single-walled carbon nanotubes (SWCNTs) with oxygen defects for cholesterol (Chol) detection using ratiometric fluorescence readouts. The interaction with Chol induced significant intensity variations in the E 11 and E 11 * emission peaks of oxygen defect-induced SWCNTs, giving rise to ratiometric fluorescence changes. The sensitivity of these probes toward Chol in water and serum was 0.28 ± 0.01 and 0.72 ± 0.05 μM, respectively, which is comparable to that of common gold standards for cholesterol detection used in clinical samples. By utilizing ratiometric readouts, our approach enhanced selectivity over numerous competing analytes, including amino acids, sugars, cations, anions, proteins, steroid hormones, surfactants, and phospholipids. Mechanistic investigations revealed that Chol detection by defect-integrated SWCNTs was facilitated by Chol incorporation within micelles formed by sodium cholate, the surfactant dispersant used for the SWCNT suspension. Oxygen defects played a crucial role by directly interacting with Chol. This strategy employing defect-integrated dual-peak NIR-emitting SWCNTs as sensors for Chol in aqueous and serum environments not only enables background-free detection of biologically relevant analytes but also advances biosensing using SWCNTs through tailored surface functionalization and advanced read-out concepts.

Cellulose produced by bacteria (BC) is considered a promising material for the textile industry, but the fragile and sensitive nature of BC membranes limits their broad applicability. Production of all-cellulose biocomposites, in which the BC is cultivated in situ on a cotton fabric, could solve this problem, but here a new issue arises, namely poor adhesion. To overcome this challenge, cotton fabric was modified with low-pressure oxygen plasma in either afterglow, E-mode, or H-mode. All-cellulose biocomposites were prepared in situ by placing the samples of cotton fabric in BC culture medium and incubating for 7 days to allow BC microfibril networks to form on the fabric. Modification of cotton fabric with oxygen plasma afterglow led to additional functionalization with polar groups, and modification with oxygen plasma in H-mode led also to etching and surface roughening of the cotton fibers, which improved the adhesion within the biocomposite. In addition, these biocomposites showed higher deformation capacities. Modification of the cotton fabric over a longer period in E-mode was found to be unsuitable, as this caused strong etching, which led to the defibrillation of cotton fibers and poor adhesion of BC. This study highlights the potential of low-pressure plasma treatment as an environmentally friendly method to improve the performance of cellulose-based biocomposites.

The lifespan, oxidizing properties, bonding behaviors, and reactivity of reactive oxygen species (ROS) produced during photocatalytic activation can vary significantly due to the differences in electron configurations of ROS, which are dependent on their generation mechanisms: energy transfer or charge transfer. Hence, identifying and differentiating ROS of different mechanisms can improve our understanding of redox reactions and related diseases, providing a basis for the prevention and treatment of related diseases. Here, we have developed a DNA framework monitor (DFM) based on dynamic DNA structural changes to effectively distinguish the two types of ROS produced in photocatalytic activation of O 2 . This DFM provides a visualization tool for observing the reaction kinetics of ROS with DNA, not only distinguishing two types of ROS with different mechanisms but also serving as a universal system for evaluating the efficacy and performance of nanomaterials for ROS regulation.

The molybdenum- and tungsten-containing formate dehydrogenases from a variety of microorganisms catalyze the reversible interconversion of formate and CO 2 ; several, in fact, function as CO 2 reductases in the reverse direction under physiological conditions. CO 2 reduction catalyzed by these enzymes occurs under mild temperature and pressure rather than the elevated conditions required for current industrial processes. Given the contemporary importance of remediation of atmospheric CO 2 to address global warming, there has been considerable interest in the application of these enzymes in bioreactors. Equally important, understanding the detailed means by which these biological catalysts convert CO 2 to formate, a useful and easily transported feedstock chemical, might also inspire the development of a new generation of highly efficient, biomimetic synthetic catalysts. Here we have examined the ability of the FdsDABG formate dehydrogenase from Cupriavidus necator to catalyze the exchange of solvent oxygen into product CO 2 during the course of formate oxidation under single-turnover conditions. Negligible incorporation of 18 O is observed when the experiment is performed in H 2 18 O, indicating that bicarbonate cannot be the immediate product of the enzyme-catalyzed reaction, as previously concluded. These results, in conjunction with the observation that the reductive half-reaction exhibits mildly acid-catalyzed rather than base-catalyzed chemistry, are consistent with a reaction mechanism involving direct hydride transfer from formate to the enzyme's molybdenum center, directly yielding CO 2 . Our results are inconsistent with any mechanism in which the initial product formed on oxidation of formate is bicarbonate.

Understanding the fate of terrestrial organic carbon (terrOC) preservation in the marine environments is critical for deciphering the biogeochemical processes associated with the global carbon cycle and the Earth's climate change. The mechanisms controlling terrOC preservation are not completely understood, while lateral oxygen exposure time (OET) is considered as a critical controlling factor. Here, we first utilized molecular dynamics simulations to investigate the structural properties of lignin under anoxic, suboxic, and oxic conditions for understanding the mechanisms of terrOC preservation during sediment lateral transport in the ocean. Our finding suggested that oxygen exposure was indispensable for terrOC degradation through influencing the structural stability and reactivity of lignin. Our simulated results showed that in suboxic environments, prolonged OET may enhance terrOC preservation. Our organic geochemical results suggested that terrOC preferably preserved in coarse silts (20-63 μm) than fine silts (<20 μm) in suboxic environments, largely due to hydrodynamics-driven prolonged OET in coarse sediments, which may efficiently reduce CO 2 emissions. Overall, our study sheds new light on the mechanisms of lateral OETs on terrOC preservation in suboxic conditions and, from a unique molecular structural perspective, provides insights into the impact of prolonged OETs on terrOC oxidative degradation in the marine environment.

Producing H 2 O 2 through a selective, two-electron (2e) oxygen reduction reaction (ORR) is challenging, especially when it serves as an advanced oxidation process (AOP) for cost-effective water decontamination. Herein, we attain a 2e-selectivity H 2 O 2 production using a carbon nanotube electrified membrane with ibuprofen (IBU) molecules laden (IBU@CNT-EM) in an ultrafast, single-pass electrofiltration process. The IBU@CNT-EM can generate H 2 O 2 at a rate of 25.62 mol g CNT -1 h -1 L -1 in the permeate with a residence time of 1.81 s. We demonstrated that an interwoven, hydrophilic-hydrophobic membrane nanostructure offers an excellent air-to-water transport platform for ORR acceleration. The electron transfer number of the ORR for IBU@CNT at neutral pH was confirmed as 2.71, elucidating a near-2e selectivity to H 2 O 2 . Density functional theory (DFT) studies validated an exceptional charge distribution of the IBU@CNT for the O 2 adsorption. The adsorption energies of the O 2 and *OOH intermediates are proportional to the H 2 O 2 selectivity (64.39%), higher than that of the CNT (37.81%). With the simple and durable production of H 2 O 2 by IBU@CNT-EM electrofiltration, the permeate can actuate Fenton oxidation to efficiently decompose emerging pollutants and inactivate bacteria. Our study introduces a new paradigm for developing high-performance H 2 O 2 -production membranes for water treatment by reusing environmental functional materials.

Simple development of an electrochemiluminescence (ECL) immunosensor for convenient detection of tumor biomarker is of great significance for early cancer diagnosis, treatment evaluation, and improving patient survival rates and quality of life. In this work, an immunosensor is demonstrated based on an enhanced ECL signal boosted by nanochannel-confined Au nanomaterial, which enables sensitive detection of the tumor biomarker-carcinoembryonic antigen (CEA). Vertically-ordered mesoporous silica film (VMSF) with a nanochannel array and amine groups was rapidly grown on a simple and low-cost indium tin oxide (ITO) electrode using the electrochemically assisted self-assembly (EASA) method. Au nanomaterials were confined in situ on the VMSF through electrodeposition, which catalyzed both the conversion of dissolved oxygen (O 2 ) to reactive oxygen species (ROS) and the oxidation of a luminol emitter and improved the electrode active surface. The ECL signal was enhanced fivefold after Au nanomaterial deposition. The recognitive interface was fabricated by covalent immobilization of the CEA antibody on the outer surface of the VMSF, followed with the blocking of non-specific binding sites. In the presence of CEA, the formed immunocomplex reduced the diffusion of the luminol emitter, resulting in the reduction of the ECL signal. Based on this mechanism, the constructed immunosensor was able to provide sensitive detection of CEA ranging from 1 pg·mL -1 to 100 ng·mL -1 with a low limit of detection (LOD, 0.37 pg·mL -1 , S/N = 3). The developed immunosensor exhibited high selectivity and good stability. ECL determination of CEA in fetal bovine serum was achieved.

The use of miniaturized probes opens a new dimension in the analysis of (bio)chemical processes, enabling the possibility to perform measurements with local resolution. In addition, multiparametric measurements are highly valuable for a holistic understanding of the investigated process. Therefore, different strategies have been suggested for simultaneous local measurements of various parameters. Electroanalytical methods are a powerful strategy in this direction. However, they have been mainly restricted to coupling concurrent independent measurements with different miniaturized probes. Here, we present an enzymatic microbiosensor for the simultaneous detection of O 2 and pH. The sensing strategy is based on the pH-dependent bioelectrocatalytic process associated with O 2 reduction at a gold microelectrode modified with a multicopper oxidase. After initial investigations of the bioelectrocatalytic reaction over gold macroelectrodes, the fabrication and characterization of micrometer-sized probes are presented. The microbioelectrode exhibits a linear current increase with O 2 concentration extending to 17.2 mg L -1 , with a sensitivity of (5.56 ± 0.13) nA L mg -1 and a limit of detection of (0.5 ± 0.3) mg L -1 . Moreover, a linear response allowing pH detection is obtained between pH 5.2 and 7.5 with a slope of -(47 ± 8) mV per pH unit. In addition, two proof-of-concept analytical examples are shown, demonstrating the capability of the developed sensing system for simultaneous local measurements of O 2 and pH. Compared with other miniaturized probes reported before for simultaneous detection, our strategy stands out as the two investigated parameters are acquired from the very same measurement. This strategy greatly simplifies the analytical setup and for the first time provides truly simultaneous local detection in the micrometer scale.

Gaseous oxygenated organic molecules (OOMs) are crucial precursors of atmospheric organic aerosols. OOMs in urban atmospheres have complex compositions, posing challenges to understanding their formation, evolution, and influences. In this study, we identify 2403 atmospheric gaseous OOMs in urban Beijing using online nitrate-based chemical ionization Orbitrap mass spectrometry based on one-year atmospheric measurements. We find that OOMs in urban atmospheres can be identified with higher accuracy and wider coverage, compared to previously used online mass spectrometry. With optimized OOM resolving capabilities, previous knowledge of OOMs in urban atmospheres can be expanded. First, clear homologous and oxygen-addition characteristics of the OOMs are revealed. Second, OOMs with lower concentrations or higher masses are identified and characterized with high confidence, e.g., OOMs with masses above 350 Da. In particular, dimers of OOMs (e.g., C 20 H 32 O 8-15 N 2 ), crucial species for organic nucleation, are identified. During four seasons, nitrogen-containing OOMs dominate the total concentration of OOMs, and OOMs are mainly from aromatic and aliphatic oxidation. Additionally, radicals with similar composition as OOMs, intermediates for OOM formation, are identified with clear diurnal variation, e.g., C n H 2 n -5 O 6 radicals ( n = 8-10) and C m H 2 m -4 NO 9 radicals ( m = 9-10), peak during the daytime and nighttime, respectively, previously having scarce measurement evidence in urban atmospheres.

Sonocatalytic therapy (SCT) has emerged as a promising noninvasive modality for tumor treatment but is hindered by the insufficient generation of ultrasound-induced reactive oxygen species (ROS) and the hypoxic tumor microenvironments. Herein, we fabricated a carbon nanoframe-confined N-coordinated manganese single-atom sonocatalyst with a five-coordinated structure (MnN 5 SA/CNF) using a phthalocyanine-mediated pyrolysis strategy. The precise coordination structure was identified by synchrotron X-ray absorption fine structure analyses. The MnN 5 SA/CNF exhibits superior and nonoxygen-dependent sonocatalytic activity owing to the optimized coordination structure and cavitation effect enhanced by defects. Additionally, density functional theory studies reveal that the five-coordination structure downshifts the d-band center of Mn from -0.547 to -0.829 eV and enhances the desorption capacity for oxygen-containing intermediates, thus accelerating the catalytic process. Finally, the as-synthesized MnN 5 SA/CNF demonstrates a significantly enhanced antitumor effect through mitochondrial apoptosis in an orthotopic breast cancer mouse model. This work explores the potential of SAzymes-supported biomedical interventions by leveraging enzymatic activity with sonocatalytic properties.

The effects of sulfur dioxide (SO 2 ) in the catalytic purification of short-chain hydrocarbons are still controversial, and the exact role of SO 2 on adsorption and reaction pathways during the catalytic oxidation of different volatile organic compounds (VOCs) remains unclear. Herein, a three-dimensional ordered macroporous Ce 0.8 Zr 0.2 O 2 supported Pt nanoparticle monolithic catalyst (Pt/OM CZO) was synthesized to investigate these effects. Our findings uncover the diverse effects of SO 2 : Upon SO 2 treatment, the coupling between the S 3p and Pt 5d orbitals promotes the Pt-O-SO 3 structure in situ formed on the catalyst surface. The propene (C 3 H 6 ) molecule readily binds with the oxygen atom in Pt-O-SO 3 , resulting in the accumulation of acetone and carbon deposition, thereby hindering C 3 H 6 oxidation. Conversely, a cleaved oxygen atom within the Pt-O-SO 3 structure enhances propane (C 3 H 8 ) adsorption and activates the C-H bond, facilitating C 3 H 8 oxidation. These insights are pivotal for advancing the frontier of sulfur-tolerant catalysts, addressing both economic and environmental challenges.

The clinical application of photodynamic therapy (PDT) is limited by oxygen-dependence and side effects caused by photosensitizer residues. Photoinitiators based on the H-abstraction reaction can address these challenges because they can generate alkyl radical-killing cells independently of oxygen and undergo rapid bleaching following H-abstraction. Nonetheless, the development of photoinitiators for PDT has been impeded by the absence of effective design strategies. Herein, we have developed aryl-ketone substituted cyanine (ACy-R), the first red-light triggered H-abstraction photoinitiators for hypoxic cancer therapy. These ACy-R molecules inherited the near-infrared absorption of cyanine dye, and aryl-ketone modification imparted H-abstraction capability. Experimental and quantum calculations revealed that modifying the electron-withdrawing groups of the aryl (e.g., ACy-5F) improved the contribution of the O atom to the photon excitation process promoting intersystem crossing and H-abstraction ability. Particularly, ACy-5F rapidly penetrated cells and enriched in the endoplasmic reticulum. Even under severe hypoxia, ACy-5F initiated red-light induced H-abstraction with intracellular biomolecules, inducing necroptosis and ferroptosis. Moreover, ACy-5F was degraded after H-abstraction, thus avoiding the side effects of long-term phototoxicity after therapy. This study not only provides a crucial molecular tool for hypoxic tumors therapy, but also presents a promising strategy for the development of multifunctional photosensitizers and photoinitiators., (© 2024 Wiley-VCH GmbH.)

Effective, precise, and controllable oxygen delivery is crucial for regulating the oxygenation balance of brain tissue at the early stages of acute ischemic stroke (AIS) because the absence of oxygen may result in a series of highly interconnected vascular-neural pathological events, including oxidative stress, inflammation, and neuroapoptosis. In this study, platelet membrane-reassembled oxygen nanobubbles (PONBs) were constructed for oxygen delivery to protect AIS. Benefiting from the preserved natural targeting ability of platelet membranes, oxygen can be controlled release into the hypoxia lesion at the preperfusion stage due to vascular injury targeting and oxygen sustained diffusion capability after PONBs administration. Furthermore, synergizing with bioactive components carried by platelet membranes, PONBs can inhibit post-AIS vascular occlusion and maintain blood-brain barrier integrity, thereby facilitating enhanced oxygen delivery of PONBs, establishing a positive feedback loop between oxygen delivery and AIS protection. Additionally, the accumulation of PONBs enhances the ultrasound imaging contrast, enabling precise localization and dynamic monitoring of AIS lesions. Thus, PONBs represent a promising strategy for the diagnosis and treatment of AIS.