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As ammonia does not emit greenhouse gases when burned, it is considered a fuel instead of fossil fuels. However, there are few reports on the corrosion behavior of materials when ammonia is used as fuel. Therefore, this study measured the hydrogen produced by the reaction between ammonia and iron using a hydrogen sensor containing a proton conductor. As a result, the amount of hydrogen produced by the decomposition of ammonia was small at low temperatures but increased at high temperatures. Also, when the ammonia content was low, oxidation of iron occurred preferentially. This way, the relationship between the amount of hydrogen generated and corrosion behavior could be clarified. [ABSTRACT FROM AUTHOR]

We have developed a family of dinuclear complexes using 2,7‐disubstituted 1,8‐naphthalenediol ligands that bind by molecular recognition to two neighboring phosphate diesters of the DNA backbone with the dinuclear CuII and NiII complexes exhibiting a severe cytotoxicity for human cancer cells. To increase the binding affinity, we intended to synthesize the corresponding dinuclear FeIII complex. Surprisingly, we obtained a tetranuclear FeIII perylene‐based complex instead of the expected dinuclear FeIII naphthalene‐based complex. In order to establish a rational and reproducible synthesis, we carefully analyzed this reaction. This revealed a multistep oxidative cascade reaction including the pre‐coordination of FeII ions in the N3‐binding pockets, the Lewis‐acid assisted MOM‐deprotection of the pre‐ligand by the pre‐oriented FeII ions, two oxidative aromatic C−C coupling reactions, oxidation of the perylene‐based backbone and of FeII to FeIII. The careful analysis of bond lengths, HOMA indices (harmonic oscillation model of aromaticity), FTIR and UV‐Vis‐NIR spectra supported by DFT calculations reveals the presence of an aromatic 18‐electron oxidized perylenequinone ligand backbone. In summary, a multistep cascade reaction involving in total a 10‐electron oxidation has been established for the straight‐forward synthesis of an unprecedented perylenequinone‐based ligand system. [ABSTRACT FROM AUTHOR]

ABSTRACT The removal of antibiotic residues from environmental media is a significant challenge in the field of chemistry. In this work, we presented a simple and efficient method for eliminating tetracycline hydrochloride (TC) and chloramphenicol (CAP) from water. Initially, 1,4‐dichlorobenzene and ferrocene were employed as starting materials for the synthesis of hypercrosslinked polymers (HFDs) via Friedel–Crafts alkylation facilitated by a cross‐linking agent. Subsequent to this, an efficient magnetic adsorbent material (MHFD) was developed by the in situ oxidation of the iron source incorporated within the polymer matrix of HFDs. The resulting MHFDs demonstrated an impressive maximum Brunauer–Emmett–Teller (BET)–specific surface area of 1190 m2/g and exhibited a peak saturation magnetization of 11.8 emu/g. This work investigated the effects of four factors on the adsorption performance of MHFD‐10, including contact time, solution pH, dosage of MHFD‐10, and initial antibiotic concentration. The results revealed a remarkable conformity of the adsorption kinetics with the pseudo‐second‐order model and the adsorption isotherms with the Langmuir model. Thermodynamic analysis revealed that the adsorption process is spontaneous and exothermic. Specifically, at a temperature of 20°C, MHFD‐10 achieved maximum adsorption capacities of 193.95 mg/g for CAP and 268.60 mg/g for TC. Furthermore, these materials exhibited exceptional reusability, maintaining high adsorption capacities even after undergoing five consecutive reuse cycles. [ABSTRACT FROM AUTHOR]

MgO-SiC-C refractories demonstrate distinguished thermal shock resistance and slag resistance, making them a promising alternative to magnesia-chrome refractories in matte smelting furnaces. Herein, we propose a novel approach to enhance both oxidation resistance and slag penetration resistance of such refractories by incorporating Si 3 N 4 -Fe powder. The results demonstrated that adding Si 3 N 4 -Fe powder effectively enhanced their overall performance. The oxidation resistance of the specimen with 6 wt% Si 3 N 4 -Fe was greatly improved because Si 3 N 4 in Si 3 N 4 -Fe could promote in-situ reactions to form more forsterite, and the FeO formed by iron oxidation could react with SiC to form Fe-Si alloys; the formed forsterite and Fe-Si alloys worked together to prevent oxygen intrusion. Meanwhile, Si 3 N 4 in Si 3 N 4 -Fe promoted the formation of forsterite layer in the corrosion area of refractories, and the reaction of Si 3 N 4 and Fe in Si 3 N 4 -Fe formed Fe-Si alloys to prevent slag penetration, which greatly improved the resistance to matte slag penetration of the refractories. [ABSTRACT FROM AUTHOR]

The study delved into the rate of browning (A420 nm) within a model wine solution, aiming to elucidate mechanisms impacting real product scenarios, including low‐ and no‐alcohol wines. The model wine solutions were prepared by adding tartaric acid, caffeic acid, and catechin into an aqueous ethanol solution containing transition metals (iron [Fe] and copper [Cu]) along with sulfur dioxide (SO2). The results indicated that the model wines without ethanol exhibited the highest browning rates both in the presence (k = 0.0022 day−1) and absence (k = 0.0035 day−1) of SO2. Notably, ethanol concentration showed a negative correlation with kinetic rates in both scenarios: with SO2 (r = −0.9317) and without SO2 (r = −0.9667). The addition of Fe and Cu separately led to a slight elevation in browning, particularly evident with Fe, while adding only Cu exhibited nonsignificant impact. However, their combined addition revealed a marked synergistic effect, rendering the rate notably sensitive to Cu concentration. [ABSTRACT FROM AUTHOR]

Highlights: The solution limit of manganese ion in BiFeO3–BaTiO3 (BF–BT) was determined by combining multiple advanced characterization methods. The defect engineering associated with fine doping can realize the co-modulation of polarization configuration, iron oxidation state and domain orientation. The BF–BT–0.2Mn piezoelectric energy harvester shows excellent power generation capacity at 250 °C, which is an important breakthrough for lead-free piezoelectric devices. High temperature piezoelectric energy harvester (HT-PEH) is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors. However, simultaneously excellent performances, including high figure of merit (FOM), insulation resistivity (ρ) and depolarization temperature (Td) are indispensable but hard to achieve in lead-free piezoceramics, especially operating at 250 °C has not been reported before. Herein, well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping. Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization, regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole, comprehensive excellent electrical performances (Td = 340 °C, ρ250 °C > 107 Ω cm and FOM250 °C = 4905 × 10–15 m2 N−1) are realized at the solid solubility limit of manganese ions. The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250 °C with high energy conversion efficiency (η = 11.43%). These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements, paving a new way in developing self-powered wireless sensors working in HT environments. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is a common cardiovascular disease often observed in diabetes mellitus, and there is currently no satisfactory therapeutic option. Ubiquitin-specific protease 38 (USP38) has been implicated in the degradation of numerous substrate proteins in the myocardium. Herein, we aim to investigate the role of USP38 in AF induced by diabetes. Cardiac-specific transgenic USP38 mice and cardiac-specific knockout USP38 mice were constructed, and streptozotocin was used to establish diabetic mouse model. Functional, electrophysiological, histologic, biochemical studies were performed. The expression of USP38 was upregulated in atrial tissues of diabetic mice and HL-1 cells exposed to high glucose. USP38 overexpression increased susceptibility to AF, accompanied by aberrant expression of calcium-handling protein, heightened iron load and oxidation stress in diabetic mice. Conversely, USP38 deficiency reduced vulnerability to AF by hampering ferroptosis. Mechanistically, USP38 bound to iron regulatory protein 2 (IRP2), stabilizing it and remove K48-linked polyubiquitination chains, thereby increasing intracellular iron overload, lipid peroxidation, and ultimately contributing to ferroptosis. In addition, reduced iron overload by deferoxamine treatment alleviated oxidation stress and decreased vulnerability to AF in diabetic mice. Overall, our findings reveal the detrimental role of USP38 in diabetes-related AF, manifested by increased level of iron overload and oxidation stress. [Display omitted] • USP38 was upregulated in the atrial tissues of diabetic mice. • USP38 overexpression increased the induction rate and mean duration of AF in diabetic mice. • Knockout of USP38 reduced susceptibility to AF in diabetic mice. • USP38 stabilized IRP2 to promote iron overload, leading to ferroptosis in diabetic mice. [ABSTRACT FROM AUTHOR]

The stability of the electrolyte plays a crucial role in influencing the efficiency of iron deposition and the quality of the resulting product. This study explores the roles of different additives, L-ascorbic acid (AA), citric acid (CA), and sodium citrate (CA-Na), in maintaining the stability of ferrous ions and investigates their effects on the hydrogen evolution and iron deposition process. Experimental results indicate that the stabilizing effects of AA, CA, and CA-Na on ferrous ions weaken in succession. The addition of AA effectively counteracts air oxidation, while the addition of CA-Na significantly inhibits hydrogen evolution reactions. These additives can form complexes or coordination compounds, engaging in coordination reactions with iron ions, thereby reducing the precipitation and oxidation of iron ions and maintaining the stability of iron ion concentration in the electrolyte. However, they also exert a certain degree of influence on the cathodic deposition of iron ions. The results of this study suggest that, in chloride aqueous solutions, the judicious addition of additives such as AA, CA, and CA-Na can effectively inhibit the oxidation of ferrous ions, maintain the stability of iron ions in the electrolyte, and concurrently suppress the occurrence of hydrogen evolution reactions. [ABSTRACT FROM AUTHOR]

The opacity/transparency, color, and production of designs in Changsha ware, a Tang dynasty Chinese stoneware renowned for its polychromy and pioneering high‐temperature red glaze, are studied by analyzing the composition, micro/nanostructure, and copper/iron speciation. The results shed new light on some of the most debated questions about Changsha ware. In particular, the role of glaze thickness, composition, and firing conditions on the coexistence of transparent and opaque glazes and of oxidized green and reduced red copper designs on the same object, and on the reason for the development of either green or turquoise colors. New data obtained by reproducing a copper red overglaze and underglaze painting with a similar glaze composition and thickness have provided new insights into the origin of the first high‐temperature copper reds and, in the absence of essential knowledge, their discontinuity. This study also contributes to the long debate regarding the use of overglaze versus underglaze painting techniques. [ABSTRACT FROM AUTHOR]

The high-temperature shaping of steels is accompanied by the formation of surface scales composed of oxide layers. However, the oxidation kinetics and morphology of these scales remain poorly understood. This study analyses the formation of oxide layers on AISI 4140 steel at varying oxidation times (20, 40 and 60 min) at 1000 °C. The analysis revealed the presence of hematite, magnetite, and transformed wustite in the oxide layers, along with clusters of alloying element oxides, predominantly chromium and iron oxide (FeCr2O4). There was a direct correlation between the duration of the oxidation process and the thickness of the scale and the number of defects observed in the material. The coating layer of alloying element oxides demonstrated insufficient adhesion to the steel substrate. Similarly, the oxides of alloying elements within this layer exhibited low cohesion among themselves. The alloying elements are present in all oxide layers, but in greater quantity in the layer in contact with the steel substrate, where a reduction in their concentrations was observed over time. This indicates that the alloying elements tend to disperse as the thickness of the alloying element oxide layer increases over time. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: It is urgent to recycle polyethylene terephthalate (PET) effectively, since it is the most consumed synthetic polyester and its improper disposal has caused significant environmental pollution. The existing chemical recycling methods highly rely on the nucleophilic substitutions and hydrogenative depolymerizations, which typically require the use of excess of nucleophiles, excess strong acids or bases, expensive metal catalysts, and explosive gas atmosphere. Here, we demonstrate a mild and efficient protocol for oxidative depolymerization of PET to terephthalic acid using only an O2 balloon. Terephthalic acid can be recycled from PET‐containing materials including a series of plastic products in daily life. The employing of relatively low loading of iron complex, the most earth‐abundant transition metal, as the catalyst and the preliminary results on the large‐scale reaction using 38 g of PET waste demonstrate the practical feasibility of this degradation method. This method can be also applicable for selective degradation of PET from mixed plastics. This work represents a rare example of a selective oxidative depolymerization and demonstrates the great potentials of such a concept in polyester recycling. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: It is urgent to recycle polyethylene terephthalate (PET) effectively, since it is the most consumed synthetic polyester and its improper disposal has caused significant environmental pollution. The existing chemical recycling methods highly rely on the nucleophilic substitutions and hydrogenative depolymerizations, which typically require the use of excess of nucleophiles, excess strong acids or bases, expensive metal catalysts, and explosive gas atmosphere. Here, we demonstrate a mild and efficient protocol for oxidative depolymerization of PET to terephthalic acid using only an O2 balloon. Terephthalic acid can be recycled from PET‐containing materials including a series of plastic products in daily life. The employing of relatively low loading of iron complex, the most earth‐abundant transition metal, as the catalyst and the preliminary results on the large‐scale reaction using 38 g of PET waste demonstrate the practical feasibility of this degradation method. This method can be also applicable for selective degradation of PET from mixed plastics. This work represents a rare example of a selective oxidative depolymerization and demonstrates the great potentials of such a concept in polyester recycling. [ABSTRACT FROM AUTHOR]

The work presented here investigates whether the TpMesFe+ moiety, which had been previously found to mediate the dioxygenation of cysteine and cysteamine, can do the same with simple thiols, which are not functionalized by an amine group. Accordingly, the complexes TpMesFeSR (R=Ph, iPr) were synthesized and after full characterization exposed to O2. They were found to react unselectively to yield sulfinates, disulfides, and thiosulfones as products. The sulfinate complex TpMesFeO2S‐p‐Tol was prepared independently and found to be air‐stable, suggesting that the additional products are not formed via overoxidation or subsequent reactions of coordinated sulfinate product. To investigate whether the larger reaction space, opened up due to the missing amine donor is responsible, a Tp‐ligand functionalized by a pyridyl donor was employed. A corresponding Tp‐iron(II) chlorido complex was prepared and converted through salt metathesis reactions into the respective thiolate analogues, which were fully characterized and structurally authenticated. However, subsequent O2 reactivity studies did not show an improved selectivity. The reason may lie in a more open reaction pocket in combination with an electronic situation which is less ideal than in case of TpMesFe(cysteamine). [ABSTRACT FROM AUTHOR]

Activation and selective oxidation of inert C(sp3)–H bonds remain one of the most challenging tasks in current synthetic chemistry due to the inherent inertness of C(sp3)–H bonds. In this study, inspired by natural monooxygenases, we developed a coordination polymer with naphthalenediimide (NDI)-based ligands and binuclear iron nodes. The mixed-valence FeIIIFeII species and chlorine radicals (Cl•) are generated via ligand-to-metal charge transfer (LMCT) between FeIII and chlorine ions. These Cl• radicals abstract a hydrogen atom from the inert C(sp3)–H bond of alkanes via hydrogen atom transfer (HAT). In addition, NDI converts oxygen to 1O2 via energy transfer (EnT), which then coordinates to FeII, forming an FeIV = O intermediate for the selective oxidation of C(sp3)–H bonds. This synthetic platform, which combines photoinduced EnT, LMCT and HAT, provides a EnT-mediated parallel multiphoton excitation strategy with kinetic synergy effect for selective C(sp3)–H oxidation under mild conditions and a blueprint for designing coordination polymer-based photocatalysts for C(sp3)–H bond oxidation. Activation and selective oxidation of inert C(sp3)–H bonds remain one of the most challenging tasks in current synthetic chemistry. Here, the authors develop a coordination polymer with naphthalenediimide-based ligands and binuclear iron nodes for the oxidation of C(sp3)-H bonds. [ABSTRACT FROM AUTHOR]

Knölker complexes have been recently used to perform the catalytic C1‐oxidation of unprotected sugars into sugar lactones. This oxidation method remained limited by the stability of the catalyst with the polyhydroxylated substrates. Our objective is now to overcome these limitations and extend this method to more challenging substrates such as disaccharides. We proposed in this paper two original designs of Knölker‐type complexes conceived to promote secondary H‐bond interactions with the OH groups of the substrates to stabilise the system and favour the transformation. In total, 8 novel pre‐catalysts were synthesised, fully characterised and applied in the anomeric oxidation of several sugar derivatives. Two of these new complexes proved to be more efficient than the Knölker complex for the oxidation of disaccharides. Moreover, a preliminary DFT study revealed the presence of H‐bonds interactions between the substrate and the oxygen atom on the ligand arm of the best complexes suggesting a beneficial role of this heteroatom on the catalytic efficiency. [ABSTRACT FROM AUTHOR]

Capacitive deionization techniques are of interest in water treatment technology due to their low cost, excellent efficiency, and environmental friendliness. Currently, metal–organic frameworks are highly impactful candidates for use as electrode materials in electrochemistry. It provides a large pore volume, good chemical stability, and a high specific surface area. Tuning metal–organic frameworks with carbon materials will have a good impact on electrode materials with increasing performance. This study shows a facile and effective strategy for arranging flow capacitive desalination technology for salt removal. The conducting network of Fe-MOF/CNTs provides rapid electron transport and offers a high diffusion length of ions. This material exhibited excellent desalination performance, with a high salt adsorption of 80.575 mg/g at 1.6 V at an initial NaCl concentration of 1000 mg/L. Overall, the facile method and fabrication strategy greatly advances water treatment applications. Highlights: Fe-MOF/CNT composites were obtained by a one-step hydrothermal process for improved CDI performance The strategy endowed the material with excellent porosity, and the presence of iron oxidation sites improved the overall conductivity of the electrode. • Fe-MOF/CNTs were used as flow electrodes for novel capacitive deionization • Fe-MOF/CNTs exhibited a high NaCl electrosorption capacity of 80.575 mg/g. Our strategy provides matching properties and an excellent combination of Fe-MOF and CNTs for improved CDI performance. [ABSTRACT FROM AUTHOR]

Microbial biostalactites and streamers commonly grow at iron seepages in abandoned mines worldwide. This study addresses the diversity and composition of these simple prokaryotic communities, which thrive in pH ranges from 2.4 to 6.6 across six different mines. Our analysis of 85 communities reveals that a pH of approximately 3.2 is a critical threshold where alpha and beta diversity change discretely. Below this pH, the average number of ASVs per sample is 2.91 times lower than above this boundary. Autotrophs, heterotrophs, and symbionts of eukaryotes originate from nearly non‐overlapping species pools in the two habitat types that differ only in pH. Communities below pH 3.2 further divide into two distinct groups, differing in diversity, taxonomic, and functional composition. Both types of communities coexist within the same stalactites, likely corresponding to zones where the capillary structure of the stalactite is either perfused or clogged. These findings indicate that microbial community structure can be significantly influenced by the intricate spatial organization of the ecosystem, rather than solely by measurable environmental parameters. [ABSTRACT FROM AUTHOR]

The aerobic and rod-shaped FO1 strain of iron-oxidizing bacteria was isolated from electroplating wastewater sludge using colloidal silica plates. Bacterial growth occurred at 25–30°C (optimum temperature, 27°C), pH 2.0–3.5, and in the presence of 1.0–4.0% NaCl. The X-ray diffraction analysis identified the precipitates that were formed during cell growth as jarosite. A biochemical analysis, including the assessments of the whole-cell fatty acids, quinone, and DNA G+C contents, revealed that FO1 was closely related to the genus Acidihalobacter. The 16S rRNA sequence of the FO1 gene was similar to those of the Acidihalobacter prosperus DSM 5130 (97% similarity), Ah. aeolianus DSM 14174 (100%), and Ah. yilgarnensis DSM 105917 (100%) strains. Antibiotic sensitivity tests of strain FO1 revealed that it was tolerant for gentamicin, kanamycin, and tetracycline, whereas it was sensitive to ampicillin and chloramphenicol. Moreover, strain FO1 was able to grow in a microbial electrolysis cell with continuous reduction of Fe3+ to Fe2+ on the cathode, albeit with a slight inhibition of cell growth. This study provides information regarding the genetics, bioleaching of metals, and electrochemical cultivation of halotolerant iron-oxidizing bacteria in the genus Acidihalobacter. [ABSTRACT FROM AUTHOR]

Acid mine drainage (AMD) pollutes natural waters, but some impacted systems show natural attenuation. We sought to identify the biogeochemical mechanisms responsible for the natural attenuation of AMD. We hypothesized that biogenic sulfide-mediated iron reduction is one mechanism and tested this in an experimental model system. We found sulfate reduction occurred under acidic conditions and identified a suite of sulfate-reducing bacteria (SRB) belonging to the groups Desulfotomaculum, Desulfobacter, Desulfovibrio, and Desulfobulbus. Iron reduction was not detected in microcosms when iron-reducing bacteria or SRB were selectively inhibited. SRB also did not reduce iron enzymatically. Rather, the biogenic sulfide produced by SRB was found to be responsible for the reduction of iron at low pH. Addition of organic substrates and nutrients stimulated iron reduction and increased the pH. X-ray diffraction and an electron microprobe analysis revealed that the polycrystalline, black precipitate from SRB bioactive samples exhibited a greater diversity of iron chalcogenide minerals with reduced iron oxidation states, and minerals incorporating multiple metals compared to abiotic controls. The implication of this study is that iron reduction mediated by biogenic sulfide may be more significant than previously thought in acidic environments. This study not only describes an additional mechanism by which SRB attenuate AMD, which has practical implications for AMD-impacted sites, but also provides a link between the biogeochemical cycling of iron and sulfur. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of a Co/Fe mixed‐metal banana‐shaped polyoxometalate with the formula [(Co2.5Fe0.5(H2O)PW9O34)2(PW6O26)]16− (Co5Fe) is reported. This transition‐metal‐substituted polyoxometalate readily assembles from its components in a one‐pot reaction and crystallizes in the monoclinic space group P21/c. The structure of Co5Fe can be considered a double sandwich composed by two B‐α‐{Co2.5Fe0.5PW9O40} Keggin units, in which one coordinatively saturated octahedral metal position is equally occupied by Co(II) and Fe(III) ions with a 50 % of site occupancy. These Keggin units are linked via a hexalacunary Keggin unit {PW6O26}. Single crystal X‐ray diffraction and magnetic measurements support the proposed atom arrangement within the crystal structure. Magnetic measurements of these double trimeric unit {Co2.5Fe0.5O13}2 show a combination of antiferromagnetic interactions, the presence of spin frustration, and the first‐order spin‐orbit coupling of Co(II) ions. Electrocatalytic water oxidation measurements show that Co5Fe displays low stability in both homogeneous and heterogeneous conditions. This is evidenced by the constant increase on the catalytic currents over time together with the appearance of polyoxometalate‐derived electrode‐bound species that can be responsible for the observed catalytic activity. [ABSTRACT FROM AUTHOR]

Iron‐catalyzed C−H amination is emerging as an attractive and sustainable method to install amine functionalities into organic compounds. Amination of C(sp3)−H bonds is usually mediated by an iron‐nitrene intermediate via a Hydrogen Atom Abstraction/Radical Recombination mechanism reminiscent of biomimetic C−H oxidation. Accordingly, this transformation can be catalyzed by engineered iron enzymes, heme and nonheme iron complexes as well as iron salts, although it is often limited to intramolecular reactions and/or activated positions. Aromatic C(sp2)−H amination is mediated by addition of electrophilic iron nitrenes or protonated N‐radical intermediates (produced with Fe catalysts) to aromatic systems. Again, high selectivity is obtained via (pseudo) intramolecular reactions. From a mechanistic perspective, several iron nitrene intermediates have been isolated and characterized over the years in different ligand scaffolds and iron oxidation states. Structure‐activity correlations have been drawn only in few cases and point to a key role of the spin density on the nitrene ligand and of the iron oxidation state. This review describes the state of the art for homogeneous iron catalyzed C(sp3)−H and C(sp2)−H amination focusing on the last 5 years (2019–2023) from a mechanism‐driven catalyst design perspective. [ABSTRACT FROM AUTHOR]

This study aims to explore the n-FeO and p-α-Fe2O3 semiconductor nanoparticles in hydrogen (HER) and oxygen (OER) evolution reactions and a combined full cell electrocatalyst system to electrolyze the water. We have observed a distinct electrocatalytic performance for both HER and OER by tuning the interplay between iron oxidation states Fe2+ and Fe3+ and utilizing phase-transformed iron oxide nanoparticles (NPs). The Fe2+ rich n-FeO NPs exhibited superior HER performance compared to p-α-Fe2O3 and Fe(OH)x NPs, which is attributed to the enhancement in n-type semiconducting nature under HER potential, facilitating the electron transfer for the reduction in H+ ions. In contrast, p-α-Fe2O3 NPs demonstrated excellent OER activity. An H-cell constructed using n-FeO||p-α-Fe2O3 NPs as cathode and anode achieved a cell voltage of 1.87 V at a current density of 50 mA/cm2. The cell exhibited remarkable stability after 30 h of activation and maintained the high current density of 100 mA/cm2 for 80 h with a negligible increase in cell voltage. This work highlights the semiconducting properties of n-FeO and p-α-Fe2O3 for the electrochemical water splitting system using the band bending phenomenon under the applied potential. [ABSTRACT FROM AUTHOR]

Mars has experienced drastic environmental evolution in terms of pH, redox, and desiccation. NASA's Curiosity rover discovered that the sediments of the Pahrump Hills member of the Murray formation in Gale Crater contained different redox states of Fe oxides. To interpret the observations, understanding the factors that control iron redox states within early Gale lakes on Mars is needed. Here, we present the results of a one-dimensional geochemical model of a closed-basin lake that considers the Fe(II) photo-oxidation reaction. Depending on the source of Fe(II) (groundwater vs. river flow), lake pH, advection rate, and atmospheric composition, we defined four types of chemical profiles in the lake; namely, Fe(II) dominated, Fe(III) dominated, carbonate precipitating, and redox-stratified profiles. The Fe(III) dominated profile corresponds to the end member case in which photo-oxidation effectively oxidizes the supplied Fe(II). The redox-stratified profile, interpreted as an intermediate condition between Fe(III) dominated profile and Fe(II) dominated profile, appears in broad parameter set when Fe(II) is supplied from the groundwater, typically with a low to moderate Fe(II) input flux at acidic to alkaline pH (pH 5–9) conditions; however, the low water flux due to the nature of the groundwater may be unable to explain the measured abundance of Fe oxides in the sediments. Another endmember case, the Fe(II) dominated profile, which would also be expected to generate mixed valence Fe oxides, occurs when the pH is acidic (pH 4–5); nevertheless, the acidic pH is inconsistent with the mineral assemblages of the sediments. Carbonate precipitating profiles were limited to the case in which Fe(II) is supplied by groundwater with high Fe input flux and alkaline pH of 8–9. These results may imply either the Fe(II) input flux was high enough for the redox-stratified case or Fe(II) photo-oxidation was suppressed by turbidity or by dusty/cloudy atmosphere, or possibly that Fe(II) oxides found in the Pahrump Hills member are, at least partly, of detrital origin. Although numerous other factors (ex., effect of lake depth, variable pH throughout the lake water, detailed chemical speciation) remain unconsidered, the diverse profiles in Fe redox resulting from Fe(II) photo-oxidation reaction sheds light on interpreting the variety and the evolution of redox condition on early Mars. [ABSTRACT FROM AUTHOR]

Hemoglobin (Hb) is a multifaceted protein, classified as a metalloprotein, chromoprotein, and globulin. It incorporates iron, which plays a crucial role in transporting oxygen within red blood cells. Hb functions by carrying oxygen from the respiratory organs to diverse tissues in the body, where it releases oxygen to fuel aerobic respiration, thus supporting the organism's metabolic processes. Hb can exist in several forms, primarily distinguished by the oxidation state of the iron in the heme group, including methemoglobin (MetHb). Measuring the concentration of MetHb is crucial because it cannot transport oxygen; hence, higher concentrations of MetHb in the blood causes methemoglobinemia. Here, we use optically detected magnetic relaxometry of paramagnetic iron spins in MetHb drop-cast onto a nanostructured diamond doped with shallow high-density nitrogen-vacancy (NV) spin qubits. We vary the concentration of MetHb in the range of 6 × 106–1.8 × 107 adsorbed Fe+3 spins per micrometer squared and observe an increase in the NV relaxation rate Γ1 (=1/T1, where T1 is the NV spin lattice relaxation time) up to 2 × 103 s−1. NV magnetic relaxometry of MetHb in phosphate-buffered saline solution shows a similar effect with an increase in Γ1 to 6.7 × 103 s−1 upon increasing the MetHb concentration to 100 μM. The increase in NV Γ1 is explained by the increased spin noise coming from the Fe+3 spins present in MetHb proteins. This study presents an additional usage of NV quantum sensors to detect paramagnetic centers of biomolecules at volumes below 100 picoliter. [ABSTRACT FROM AUTHOR]

The present work aims to investigate the effect of heating temperature (400, 600 and 800 °C) and inoculating elements (Ca, Ca-Ba, Ca-RE) on oxidation behavior of ductile irons containing 5.25% Si and 4.8% Si-2.3% Mo in dry air and combustion gas containing water vapour (natural gas burning). The oxidation is influenced by the gas atmosphere type, the iron alloying system, and the inoculating elements depending on the heating temperature. The weight gain increases from 0.001%-0.1% (400 °C) to 0.05%-0.70% (600 °C) and up to 0.10%-2.15% (800 °C). No particular effects of the considered influencing factors are found when heating at 400 °C, while at 600 °C, mainly the oxidation gas atmosphere type shows a visible influence. At the highest heating temperature of 800 °C, a limited increase of the weight gain is found for dry air atmosphere (up to 0.25%), but it drastically increases for combustion atmospheres (0.65%-2.15%). The water vapour presence in the combustion atmosphere is an important oxidising factor at 600-800 °C. The alloying system appears to influence the oxidation behavior mainly at a heating temperature of 800 °C in the combustion atmosphere, as evidenced by the lower weight gain in 5.25% silicon cast iron. Positive effects of inoculating elements increase with the heating temperature, with Ca and Ba-FeSi inoculation generally showing better performance. Irons inoculated with CaRE-FeSi exhibit a higher degree of oxidation. These results are in good relationship with the previous reported data: Ca-Ba-inoculation system appears to be better than simple Ca for improving the graphite parameters, while RE-bearing inoculant negatively affects the compactness degree of graphite particles in high-Si ductile irons. As the lower compactness degree is typical for graphite nodules in high-Si ductile irons, which negatively affects the oxidation resistance, it is necessary to employ specific metallurgical treatments to improve nodule quality. Inoculation, in particular, is a potential method to achieve this improvement. [ABSTRACT FROM AUTHOR]

[Display omitted] The 57Fe Mössbauer isomer shift is not directly related to the oxidation state of iron, and therefore the evaluation of the oxidation state of iron from the isomer shift is problematic. The oxidation state affects the isomer shift only to the extent that it affects the Fe–X bond lengths. The isomer shift can be estimated based on the average Fe–X interatomic distance. [ABSTRACT FROM AUTHOR]

Leptothrix ochracea creates distinctive iron-mineralized mats that carpet streams and wetlands. Easily recognized by its iron-mineralized sheaths, L. ochracea was one of the first microorganisms described in the 1800s. Yet it has never been isolated and does not have a complete genome sequence available, so key questions about its physiology remain unresolved. It is debated whether iron oxidation can be used for energy or growth and if L. ochracea is an autotroph, heterotroph, or mixotroph. To address these issues, we sampled L. ochracea-rich mats from three of its typical environments (a stream, wetlands, and a drainage channel) and reconstructed nine high-quality genomes of L. ochracea from metagenomes. These genomes contain iron oxidase genes cyc2 and mtoA, showing that L. ochracea has the potential to conserve energy from iron oxidation. Sox genes confer potential to oxidize sulfur for energy. There are genes for both carbon fixation (RuBisCO) and utilization of sugars and organic acids (acetate, lactate, and formate). In silico stoichiometric metabolic models further demonstrated the potential for growth using sugars and organic acids. Metatranscriptomes showed a high expression of genes for iron oxidation; aerobic respiration; and utilization of lactate, acetate, and sugars, as well as RuBisCO, supporting mixotrophic growth in the environment. In summary, our results suggest that L. ochracea has substantial metabolic flexibility. It is adapted to iron-rich, organic carbon-containing wetland niches, where it can thrive as a mixotrophic iron oxidizer by utilizing both iron oxidation and organics for energy generation and both inorganic and organic carbon for cell and sheath production. [ABSTRACT FROM AUTHOR]

Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that plays an important role in biogeochemical iron and sulfur cycling and is a member of the consortia used in industrial hydrometallurgical processing of copper. Metal sulfide bioleaching is catalyzed by the regeneration of ferric iron; however, bioleaching of chalcopyrite, the dominant unmined form of copper on Earth, is inhibited by surface passivation. Here, we report the implementation of CRISPR interference (CRISPRi) using the catalytically inactive Cas12a (dCas12a) in A. ferrooxidans to knock down the expression of genes in the petI and petII operons. These operons encode bc1 complex proteins and knockdown of these genes enabled the manipulation (enhancement or repression) of iron oxidation. The petB2 gene knockdown strain enhanced iron oxidation, leading to enhanced pyrite and chalcopyrite oxidation, which correlated with reduced biofilm formation and decreased surface passivation of the minerals. These findings highlight the utility of CRISPRi/dCas12a technology for engineering A. ferrooxidans while unveiling a new strategy to manipulate and improve bioleaching efficiency. [ABSTRACT FROM AUTHOR]

This document is a special issue of the journal Catalysts titled "Advances in Catalytic Oxidation of Methane and Carbon Monoxide (2nd Edition)." It consists of seven articles that discuss the catalytic removal of carbon monoxide and methane, which are harmful pollutants produced by human activities. The articles cover topics such as CO oxidation, CH4 combustion, and the partial oxidation of CH4 to oxygenates. The authors explore various catalysts and their effectiveness in removing these pollutants. The document provides valuable insights into the oxidation of CO and the complete or partial oxidation of methane using different catalysts. [Extracted from the article]

A strategy for vaccine design involves identifying proteins that could be involved in pathogen–host interactions. The aim of this proteomic study was to determine how iron limitation affects the protein expression of Tenacibaculum dicentrarchi, with a primary focus on virulence factors and proteins associated with iron uptake. The proteomic analysis was carried out using two strains of T. dicentrarchi grown under normal (control) and iron‐limited conditions, mimicking the host environment. Our findings revealed differences in the proteins expressed by the type strain CECT 7612T and the Chilean strain TdCh05 of T. dicentrarchi. Nonetheless, both share a common response to iron deprivation, with an increased expression of proteins associated with iron oxidation and reduction metabolism (e.g., SufA, YpmQ, SufD), siderophore transport (e.g., ExbD, TonB‐dependent receptor, HbpA), heme compound biosynthesis, and iron transporters under iron limitation. Proteins involved in gliding motility, such as GldL and SprE, were also upregulated in both strains. A negative differential regulation of metabolic proteins, particularly those associated with amino acid biosynthesis, was observed under iron limitation, reflecting the impact of iron availability on bacterial metabolism. Additionally, the TdCh05 strain exhibited unique proteins associated with gliding motility machinery and phage infection control compared to the type strain. These groups of proteins have been identified as virulence factors within the Flavobacteriaceae family, including the genus Tenacibaculum. These results build upon our previous report on iron acquisition mechanisms and could lay the groundwork for future studies aimed at elucidating the role of some of the described proteins in the infectious process of tenacibaculosis, as well as in the development of potential vaccines. [ABSTRACT FROM AUTHOR]

Comprehending the anaerobic nitrogen transformations, including denitrification, anaerobic ammonium oxidation (anammox), and anaerobic ammonium oxidation linked with iron reduction (Feammox) in soil, is essential for improving soil fertility and minimizing the environmental impacts of nitrogen loss. Despite this, research on anaerobic nitrogen transformations, particularly Feammox in paddy soil, is sparse. This study examined soil denitrification, anammox, and Feammox, along with their respective contributions to nitrogen loss in paddy soil at various depths, under different fertilization and irrigation treatments. It utilized 15N isotope labeling to investigate the limiting factors of these anaerobic nitrogen transformations and their interactions. The findings showed that denitrification rates ranged from 0.41 to 2.12 mg N kg−1 d−1, while anammox rates ranged from 0.062 to 0.394 mg N kg−1 d−1, contributing 84.3% to 88.1% and 11.8% to 15.7% of total soil nitrogen loss, respectively. Denitrification was identified as the predominant pathway for nitrogen loss across different soil depths. Fertilization and irrigation had more pronounced impacts on anaerobic nitrogen transformations than did soil depth, potentially affecting these processes through both abiotic and biotic pathways. This study identified significant correlations among the three types of anaerobic nitrogen transformations. These findings offer a theoretical foundation for optimizing nitrogen management strategies to mitigate losses in agricultural systems. [ABSTRACT FROM AUTHOR]

Introduction: Electrostatic binding of deoxyhemoglobin (Hb) to cytoplasmic domain of band 3 anion transport protein occurs as part of the glycolytic regulation in red blood cells (RBCs). Hb oxidation intermediates not only impact RBC's oxygenation but also RBC's membrane through the interaction with band 3. It is not known however whether these critical pathways undergo changes during the storage of RBCs. Methods and Results: Oxygen parameters of fresh blood showed a sigmoidal and cooperative oxygen dissociation curve (ODC) for the first week of storage. This was followed by a large drop in oxygen affinity (P50) (from 30 to 20 mmHg) which remained nearly unchanged with a slight elevation in Bohr coefficients and a significant drop in extracellular acidification rates (ECAR) at the 42-day storage. Oxidation of Hb increased with time as well as the formation of a highly reactive ferryl Hb under oxidative stress conditions. Ferryl Hb interacted avidly with RBC's membrane's band 3, but to lesser extent with old ghost RBCs. Discussion: The observed alterations in RBC's oxygen binding may have been affected by the alterations in band 3's integrity which are largely driven by the internal iron oxidation of Hb. Restoring oxygen homeostasis in stored blood may require therapeutic interventions that target changes in Hb oxidation and membrane changes. [ABSTRACT FROM AUTHOR]

Defective mitochondria and autophagy, as well as accumulation of lipid and iron in WDR45 mutant fibroblasts, is related to beta-propeller protein-associated neurodegeneration (BPAN). In this study, we found that enlarged lysosomes in cells derived from patients with BPAN had low enzyme activity, and most of the enlarged lysosomes had an accumulation of iron and oxidized lipid. Cryo-electron tomography revealed elongated lipid accumulation, and spectrometry-based elemental analysis showed that lysosomal iron and oxygen accumulation superimposed with lipid aggregates. Lysosomal lipid aggregates superimposed with autofluorescence as free radical generator, lipofuscin. To eliminate free radical stress by iron accumulation in cells derived from patients with BPAN, we investigated the effects of the iron chelator, 2,2′-bipyridine (bipyridyl, BIP). To study whether the defects in patient-derived cells can be rescued by an iron chelator BIP, we tested whether the level of iron and reactive oxygen species (ROS) in the cells and genes related to oxidative stress were rescued BIP treatment. Although BIP treatment decreased some iron accumulation in the cytoplasm and mitochondria, the accumulation of iron in the lysosomes and levels of cellular ROS were unaffected. In addition, the change of specific RNA levels related to free radical stress in patient fibroblasts was not rescued by BIP. To alleviate free radical stress, we investigated whether l -serine can regulate abnormal structures in cells derived from patients with BPAN through the regulation of free radical stress. l -serine treatment alleviated increase of enlarged lysosomes and iron accumulation and rescued impaired lysosomal activity by reducing oxidized lipid accumulation in the lysosomes of the cells. Lamellated lipids in the lysosomes of the cells were identified as lipofuscin through correlative light and electron microscopy, and l -serine treatment reduced the increase of lipofuscin. These data suggest that l -serine reduces oxidative stress-mediated lysosomal lipid oxidation and iron accumulation by rescuing lysosomal activity. [Display omitted] • WDR45 mutant fibroblasts show abnormal iron and lipid accumulation in lysosomes. • WDR45 mutant fibroblasts show dysfunctional lysosome activity. • The iron chelator was unable to regulate the accumulation of iron and lipids in the lysosome. • l -serine can regulate iron and lipid accumulation through lysosomal activity. [ABSTRACT FROM AUTHOR]

Iron-based Fischer–Tropsch synthesis (FTS) catalyst is widely used for syngas conversion, but its iron carbide active phase is easily oxidized into Fe3O4 by the water produced during reaction, leading to the deterioration of catalytic performance. Here, we show an efficient strategy for protecting the iron carbide active phase of FTS catalyst by surface hydrophobization. The hydrophobic surface can reduce the water concentration in the core vicinity of catalyst during syngas conversion, and thus inhibit the oxidation of iron species by water, which enhances the C − C coupling ability of catalyst and promotes the formation of long-chain olefins. More significantly, it is unraveled that appropriate shell thickness plays a crucial role in stabilizing the iron carbide active phase without Fe3O4 formation and achieving good catalytic performance. The iron carbide active phase is easily oxidized by the water produced during Fischer-Tropsch synthesis, which leads to a deterioration in catalytic performance. Here, the authors present a strategy to protect iron carbide by applying surface hydrophobization. [ABSTRACT FROM AUTHOR]

Fe-modified Cu catalysts with CeO2 support, prepared by the impregnation method, were subjected to physicochemical analysis and catalytic tests in the steam reforming of methanol (SRM). Physicochemical studies of the catalysts were carried out using the XRF, TEM, STEM-EDS, XRD, TPR and nitrogen adsorption/desorption methods. XRD, TEM studies and catalytic tests of the catalysts were carried out at two reduction temperatures, 260 °C and 400 °C, to determine the relationship between the form and oxidation state of the active phase of the catalysts and the catalytic properties of these systems in the SRM. Additionally, the catalysts after the reaction were analysed for the changes in the structure and morphology using TEM methods. The presented results show that the composition of the catalysts, morphology, structure, form and oxidation state of the Cu and Fe active metals in the catalysts and the reaction temperature significantly impact their activity, selectivity and stability in the SRM process. The gradual deactivation of the studied catalysts under SRM conditions could result from the forming of carbon deposits and/or the gradual oxidation of the copper and iron phases under the reaction conditions. [ABSTRACT FROM AUTHOR]

Free interconversion of cytochrome C (CytC) between native ferrous (Cyt‐FeII) and oxidized ferric (CytC‐FeIII) states is necessary to maintain the respiratory function of mitochondria. Disturbances in CytC‐FeIII to total CytC ratio may indicate mitochondrial dysfunction and apoptosis. Thus, tracking CytC oxidation state delivers important information about cellular physiology. In this work, we propose a novel methodology based on resonance Raman (rR) imaging optimized uniquely to track and qualitatively analyze the transition of Cyt‐FeII to CytC‐FeIII within live cells without affecting their morphology. None of the commonly used excitation lines allows such clear‐cut differentiation, contrary to the 405 nm applied in this work. The presented methodology provides a novel pathway in the label‐free detection of ferrous and ferric heme proteins. [ABSTRACT FROM AUTHOR]

Green hydrogen is poised to play a crucial role in the energy-transition process in developed countries over the coming years, particularly in those countries aiming to achieve net-zero emissions. Consequently, the for green hydrogen is expected to rise significantly. This article explores the fundamental methods of producing hydrogen, focusing on the oxidation reaction within a thermochemical solar cycle for the dissociation of steam. Solar thermochemical cycles have been extensively researched, yet they remain in the development stage as research groups strive to identify optimal materials and conditions to enhance process efficiency, especially at high temperatures. The article analyses theoretical foundations drawn from exhaustive scientific studies related to the oxidation of iron in steam, the relationship with the activation energy of the corrosive process, thermodynamic aspects, and the kinetic model of a heterogeneous reaction. Additionally, it presents various mechanisms of high-temperature oxidation, pH effects, reactors, and materials (including fluidized beds). This scientific review suggests that hydrogen production via a thermochemical cycle is more efficient than production via electrochemical processes (such as electrolysis), provided the limitations of the cycle's reduction stage can be overcome. [ABSTRACT FROM AUTHOR]

The role of sediment oxygen demand (SOD) in causing dissolved oxygen (DO) depletion is widely acknowledged, with previous studies mainly focusing on chemical and biological SOD separately. However, the relationship between the putative functions of sediment microbes and SOD, and their impact on DO depletion in overlying water, remains unclear. In this study, DO depletion was observed in the downstream of the Gan River during the summer. Sediments were sampled from three downstream sites (YZ, Down1, and Down2) and one upstream site (CK) as a control. Aquatic physicochemical parameters and SOD levels were measured, and microbial functions were inferred from taxonomic genes through analyses of the 16S rRNA gene. The results showed that DO depletion sites exhibited a higher SOD rate compared to CK. The microbial community structure was influenced by the spatial variation of Proteobacteria, Chloroflexi, and Bacteroidota, with total organic carbon (TOC) content acting as a significant environmental driver. A negative correlation was observed between microbial diversity and DO concentration (p < 0.05). Aerobic microbes were more abundant in DO depletion sites, particularly Proteobacteria. Microbes involved in various biogeochemical cycles, such as carbon (methane oxidation, methanotrophs, and methylotrophs), nitrogen (nitrification and denitrification), sulfur (sulfide and sulfur compound oxidation), and manganese cycles (manganese oxidation), exhibited higher abundance in DO depletion sites, except for the iron cycle (iron oxidation). These processes were negatively correlated with DO concentration and positively with SOD (p < 0.05). Overall, the results highlight that aerobic bacteria's metabolic processes consume oxygen, increasing the SOD rate and contributing to DO depletion in the overlying water. Additionally, the study underscores the importance of targeting the removal of in situ microbial molecular mechanisms associated with toxic H2S and CH4 to support reoxygenation efforts in rehabilitating DO depletion sites in the Gan River, aiding in identifying factors controlling DO consumption and offering practical value for the river's restoration and management. [ABSTRACT FROM AUTHOR]

The carbon‐free chemical storage and release of renewable energy is an important task to drastically reduce CO2 emissions. The high specific energy density of iron and its recyclability makes it a promising storage material. Energy release by oxidation with air can be realized by the combustion of micron‐sized iron powders in retro‐fitted coal fired power plants and in fixed‐bed reactors under milder conditions. An experimental parameter study of iron powder oxidation with air was conducted based on thermogravimetric analysis in combination with wide‐angle X‐ray scattering and Mössbauer spectroscopy. In agreement with literature the oxidation was found to consist of a very fast initial oxidation of the outer particle layer followed by much slower oxidation due to diffusion of iron ions through the Fe2O3/Fe3O4 layer being the rate‐limiting step. Scanning electron microscopy analysis of the iron particle before and after oxidation reveal a strong particle morphology transformation. This impact on the reaction was studied by cyclization experiments. Up to 10 oxidation‐reduction cycles show that both, oxidation and reduction rates, increase strongly with cycling due to increased porosity. [ABSTRACT FROM AUTHOR]

Heme is essential for a variety of proteins involved in vital physiological functions in the body, such as oxygen transport, drug metabolism, biosynthesis of steroids, signal transduction, antioxidant defense and mitochondrial respiration. However, free heme is potentially cytotoxic due to the capacity of heme iron to promote the oxidation of cellular molecules. The liver plays a central role in heme metabolism by significantly contributing to heme synthesis, heme detoxification, and recycling of heme iron. Conversely, enzymatic defects in the heme biosynthetic pathway originate multisystemic diseases (porphyrias) that are highly associated with liver damage. In addition, there is growing evidence that heme contributes to the outcomes of inflammatory, metabolic and malignant liver diseases. In this review, we summarize the contribution of the liver to heme metabolism and the association of heme dyshomeostasis with liver disease. [ABSTRACT FROM AUTHOR]

Platinum-based catalysts that have long been used as the anodes for the formic acid electro-oxidation (FAO) in the direct formic acid fuel cells (DFAFCs) were susceptible to retrogradation in performance due to CO poisoning that impaired the technology transfer in industry. This work is designed to overcome this challenge by amending the Pt surface sequentially with nanosized cobalt (nano-CoOx, fibril texture of ca. 200 nm in particle size) and iron (nano-FeOx, nanorods of particle size and length of 80 and 253 nm, respectively) oxides. This enriched the Pt surface with oxygenated groups that boosted FAO and mitigated the CO poisoning. The unfilled d-orbitals of the transition metals and their tendency to vary their oxidations states presumed their participation in a faster mechanism of FAO. Engineering the Pt surface in this FeOx/CoOx/Pt hierarchy resulted in a remarkable activity toward FAO, that exceeded four times that of the Pt catalyst with up to ca. 2.5 times improvement in the catalytic tolerance against CO poisoning. This associated a ca. − 32 mV shift in the onset potential of FAO which increased to − 40 mV with a post-activation of the same catalyst at − 0.5 in 0.2 mol L–1 NaOH, displaying the catalyst's competitiveness in reducing overpotentials in DFAFCs. It also exhibited a favorable amelioration in the catalytic durability in long-termed chronoamperometric electrolysis. The electrochemical impedance spectroscopy and the CO stripping voltammetry were employed to elucidate the origin of enhancement. [ABSTRACT FROM AUTHOR]

Sea coastal soils are functioning on the contact of terrigenous runoff and the seawater impact, which provides a unique geochemical environment. Migration and accumulation of elements can be partially promoted by the formation and oxidation of iron sulfides. We studied the content and spatial distribution of Fe, Mn and trace elements in the marsh soils of the Pomor coast of the White Sea. The work was carried out near the village of Kolezhma, Belomorsk district, Republic of Karelia. The study revealed the elevated concentrations of trace elements in these soils, such as As and Se, which are usually associated with metal sulfides in marine sediments. A high content of Fe and Mn was registered, i.e., up to 27 300 and 1500 ppm, respectively, which is typical for taiga landscapes. At the same time, the geochemical fate of Fe and Mn is different in coastal soils, probably partly due to the participation of Fe in mineral transitions from sulfides to sulfates. Such microelements as Ni and Cr are present in the soils in concentrations comparable to the background concentrations in the regional zonal soils. Only As and Se may be potentially toxic, if tombolo is used as a hayfield. [ABSTRACT FROM AUTHOR]

The root microbiota plays a crucial role in assisting the plant host in combating various biotic and abiotic stresses, notably drought, which poses a significant threat to global food security. Despite extensive efforts to understand the shifts in rhizosphere and endosphere bacteriomes, there remains a gap in comprehending how drought stress influences the co-occurring network patterns within these compartments and their ecological functional potentials. To address this gap, a pot experiment was conducted with two treatments: continuous flooding as a control and drought treatment. Bulk soil, rhizosphere, and endosphere samples were collected and subjected to high-throughput sequencing and bioinformatics analysis. The results revealed that drought stress significantly reduced the rice biomass but increased the Shannon diversity index in both the rhizosphere and endosphere bacterial communities with no observable effect on richness across compartments. Additionally, drought treatment markedly altered the community structure and bacterial assemblages in these compartments, resulting in the specific enrichment of Actinobacteriota, Gemmatimonadetes, and Patescibacteria, while Bacteroidetes and Firmicutes were depleted in the rhizosphere and endosphere. Furthermore, drought heightened the complexity of the co-occurring networks and the proportions of positive links across all sampling compartments; this effect was accompanied by an increase in the number of connectors in the bulk soil and rhizosphere, as well as module hubs in the rhizosphere. Functional potential prediction indicated that drought stress significantly altered multiple potential ecological functions across all sampling compartments, particularly enriching functions related to the oxidation of sulfur, manganese, and hydrogen in the bulk soil, while functions associated with iron oxidation were significantly depleted in the rhizosphere. Overall, our results demonstrate that under drought stress, rice may specifically enrich certain bacterial taxa and enhance their positive interactions within its root system to improve adaptation. [ABSTRACT FROM AUTHOR]

In this research, the heterogeneous catalysts of Fe3O4@SiO@TiO‐FePc and Fe3O4@SiO@TiO‐ CuPcN (FePc = iron (II) phthalocyanine and CuPcN = copper (II) tetraazaphthalocyanine), termed respectively as nanocomposites 1 and 2, were prepared by immobilizing the FePc and CuPcN complexes on the Fe3O4@SiO@TiO surface and used for the photocatalytic water oxidation reaction. Since phthalocyanine complexes have received very little attention as photocatalysts for water oxidation, the advantage of the synthesized photocatalyst owes to the ability of the phthalocyanine complex grafted on the titanium substrate to oxidize water in the photocatalytic reaction. The prepared nanocomposites were then studied by diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), Fourier transform infrared (FT‐IR) spectroscopies, thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), inductively coupled plasma‐optical emission spectroscopy (ICP‐OES), Brunauer–Emmett–Teller (BET) analysis, ultraviolet diffuse reflectance (DRS), and photoluminescence (PL) spectroscopies. The photocatalytic response of water oxidation by nanocomposites 1 and 2 was investigated in the presence of silver nitrate as an electron recipient at ambient temperature. The progress of the water oxidation reaction was monitored with an oxygen meter. The amount of oxygen generated in the presence of nanocomposites 1 and 2 under visible light irradiation was found to be 2.6 and 2.1 mg L−1, respectively. Owing to the existence of magnetic material, these nanocomposites can be effortlessly removed from the response medium with an external magnet. The involved nanocomposites can be used up to three times in catalytic water oxidation reactions with no significant change in their photocatalytic activity. [ABSTRACT FROM AUTHOR]

Growing evidence suggests that the hydrochemical properties of geothermal fumaroles may play a crucial role in shaping the diversity and functions of microbial communities in various environments. In the present study, the impact of geothermal furaneols on the microbial communities and their metabolic functions across the rock‐soil‐plant continuum was explored considering varying distances from the fumarole source. The results revealed that bacterial phylum Proteobacteria was predominant in all sample types, except in the 10 m rock sample, irrespective of the sampling distance. Archaeal phyla, such as Euryarchaeota and Crenarchaeota, were more prevalent in rock and soil samples, whereas bacterial phyla were more prevalent in plant samples. Thermoacidophilic archaeons, including Picrophilus, Ferroplasma, and Thermogymnomonas were dominant in rocks and soil samples of 1 and 5 m distances; acidophilic mesophiles, including Ferrimicrobium and Granulicella were abundant in the rhizoplane samples, whereas rhizosphere‐associated microbes including Pseudomonas, Pedobacter, Rhizobium, and Novosphingobium were found dominant in the rhizosphere samples. The functional analysis highlighted the higher expression of sulfur oxidative pathways in the rock and soil samples; dark iron oxidation and nitrate/nitrogen respiratory functions in the rhizosphere samples. The findings underscore microbial adaptations across the rock‐soil‐plant continuum, emphasizing the intricate relationship between geothermal fumaroles and microbial communities in adjacent ecosystems. These insights offer a crucial understanding of the evolution of microbial life and highlight their pivotal roles in shaping ecosystem dynamics and functions. [ABSTRACT FROM AUTHOR]

Photothermal therapy (PTT) can overcome cancer treatment resistance by enhancing the cell membrane permeability, facilitating drug accumulation, and promoting drug release within the tumor tissue. Iron oxide nanoparticles (IONPs) have emerged as effective agents for PTT due to their unique properties and biocompatibility. Approved for the treatment of anemia, as MRI contrast agents, and as magnetic hyperthermia mediators, IONPs also offer excellent light-to-heat conversion and can be manipulated using external magnetic fields for targeted accumulation in specific tissue. Optimizing parameters such as the laser wavelength, power density, shape, size, iron oxidation state, functionalization, and concentration is crucial for IONPs' effectiveness. In addition to PTT, IONPs enhance other cancer treatment modalities. They improve tumor oxygenation, enhancing the efficacy of radiotherapy and photodynamic therapy. IONPs can also trigger ferroptosis, a programmed cell death pathway mediated by iron-dependent lipid peroxidation. Their magneto-mechanical effect allows them to exert a mechanical force on cancer cells to destroy tumors, minimizing the damage to healthy tissue. This review outlines strategies for the management of the photothermal performance and PTT efficiency with iron oxide nanoparticles, as well as synergies with other cancer therapies. [ABSTRACT FROM AUTHOR]

Ferroptosis is a form of non-apoptotic regulated cell death (RCD) that depends on iron and is characterized by the accumulation of lipid peroxides to lethal levels. Ferroptosis involves multiple pathways including redox balance, iron regulation, mitochondrial function, and amino acid, lipid, and glycometabolism. Furthermore, various disease-related signaling pathways also play a role in regulating the process of iron oxidation. In recent years, with the emergence of the concept of ferroptosis and the in-depth study of its mechanisms, ferroptosis is closely associated with various biological conditions related to kidney diseases, including kidney organ development, aging, immunity, and cancer. This article reviews the development of the concept of ferroptosis, the mechanisms of ferroptosis (including GSH-GPX4, FSP1-CoQ1, DHODH-CoQ10, GCH1-BH4, and MBOAT1/2 pathways), and the latest research progress on its involvement in kidney diseases. It summarizes research on ferroptosis in kidney diseases within the frameworks of metabolism, reactive oxygen biology, and iron biology. The article introduces key regulatory factors and mechanisms of ferroptosis in kidney diseases, as well as important concepts and major open questions in ferroptosis and related natural compounds. It is hoped that in future research, further breakthroughs can be made in understanding the regulation mechanism of ferroptosis and utilizing ferroptosis to promote treatments for kidney diseases, such as acute kidney injury(AKI), chronic kidney disease (CKD), diabetic nephropathy(DN), and renal cell carcinoma. This paves the way for a new approach to research, prevent, and treat clinical kidney diseases. [ABSTRACT FROM AUTHOR]

Background: Microbial methane oxidation, methanotrophy, plays a crucial role in mitigating the release of the potent greenhouse gas methane from aquatic systems. While aerobic methanotrophy is a well-established process in oxygen-rich environments, emerging evidence suggests their activity in hypoxic conditions. However, the adaptability of these methanotrophs to such environments has remained poorly understood. Here, we explored the genetic adaptability of aerobic methanotrophs to hypoxia in the methanogenic sediments of Lake Kinneret (LK). These LK methanogenic sediments, situated below the oxidic and sulfidic zones, were previously characterized by methane oxidation coupled with iron reduction via the involvement of aerobic methanotrophs. Results: In order to explore the adaptation of the methanotrophs to hypoxia, we conducted two experiments using LK sediments as inoculum: (i) an aerobic "classical" methanotrophic enrichment with ambient air employing DNA stable isotope probing (DNA-SIP) and (ii) hypoxic methanotrophic enrichment with repeated spiking of 1% oxygen. Analysis of 16S rRNA gene amplicons revealed the enrichment of Methylococcales methanotrophs, being up to a third of the enriched community. Methylobacter, Methylogaea, and Methylomonas were prominent in the aerobic experiment, while hypoxic conditions enriched primarily Methylomonas. Using metagenomics sequencing of DNA extracted from these experiments, we curated five Methylococcales metagenome-assembled genomes (MAGs) and evaluated the genetic basis for their survival in hypoxic environments. A comparative analysis with an additional 62 Methylococcales genomes from various environments highlighted several core genetic adaptations to hypoxia found in most examined Methylococcales genomes, including high-affinity cytochrome oxidases, oxygen-binding proteins, fermentation-based methane oxidation, motility, and glycogen use. We also found that some Methylococcales, including LK Methylococcales, may denitrify, while metals and humic substances may also serve as electron acceptors alternative to oxygen. Outer membrane multi-heme cytochromes and riboflavin were identified as potential mediators for the utilization of metals and humic material. These diverse mechanisms suggest the ability of methanotrophs to thrive in ecological niches previously thought inhospitable for their growth. Conclusions: Our study sheds light on the ability of enriched Methylococcales methanotrophs from methanogenic LK sediments to survive under hypoxia. Genomic analysis revealed a spectrum of genetic capabilities, potentially enabling these methanotrophs to function. The identified mechanisms, such as those enabling the use of alternative electron acceptors, expand our understanding of methanotroph resilience in diverse ecological settings. These findings contribute to the broader knowledge of microbial methane oxidation and have implications for understanding and potential contribution methanotrophs may have in mitigating methane emissions in various environmental conditions. [ABSTRACT FROM AUTHOR]