Ferric Research Articles

Enhancing microfiltration membrane performance by sodium percarbonate-based oxidation for hydraulic fracturing wastewater treatment

Low pressure membrane takes a great role in hydraulic fracturing wastewater (HFW), while membrane fouling is a critical issue for the stable operation of microfiltration (MF). This study focused on fouling mitigation by sodium percarbonate (SPC) oxidation, activated by ultraviolet (UV) and ferrous ion (Fe(II)). The higher the concentration of oxidizer, the better the anti-fouling performance of MF membrane. Unlike severe MF fouling without oxidation (17.26 L/(m2·h)), UV/SPC and Fe(II)/SPC under optimized dosage improved the final flux to 740 and 1553 L/(m2·h), respectively, and the latter generated Fe(III) which acted as a coagulant. Fe(II)/SPC oxidation enabled a shift in fouling mechanism from complete blocking to cake filtration, while UV/SPC oxidation changed it to standard blockage. UV/SPC oxidation was stronger than Fe(II)/SPC oxidation in removing UV254 and fluorescent organics for higher oxidizing capacity, but the opposite was noted for DOC removal. The deposited foulants on membrane surface after oxidation decreased by at least 88% compared to untreated HFW. Correlation analysis showed that UV254, DOC and organic fraction were key parameters responsible for membrane fouling (correlation coefficient＞0.80), oxidizing capacity and turbidity after oxidation were also important parameters. These results provide new insights for fouling control during the HFW treatment.

Diffusion Correction in Fricke Hydrogel Dosimeters: A Deep Learning Approach with 2D and 3D Physics-Informed Neural Network Models.

In this work an innovative approach was developed to address a significant challenge in the field of radiation dosimetry: the accurate measurement of spatial dose distributions using Fricke gel dosimeters. Hydrogels are widely used in radiation dosimetry due to their ability to simulate the tissue-equivalent properties of human tissue, making them ideal for measuring and mapping radiation dose distributions. Among the various gel dosimeters, Fricke gels exploit the radiation-induced oxidation of ferrous ions to ferric ions and are particularly notable due to their sensitivity. The concentration of ferric ions can be measured using various techniques, including magnetic resonance imaging (MRI) or spectrophotometry. While Fricke gels offer several advantages, a significant hurdle to their widespread application is the diffusion of ferric ions within the gel matrix. This phenomenon leads to a blurring of the dose distribution over time, compromising the accuracy of dose measurements. To mitigate the issue of ferric ion diffusion, researchers have explored various strategies such as the incorporation of additives or modification of the gel composition to either reduce the mobility of ferric ions or stabilize the gel matrix. The computational method proposed leverages the power of artificial intelligence, particularly deep learning, to mitigate the effects of ferric ion diffusion that can compromise measurement precision. By employing Physics Informed Neural Networks (PINNs), the method introduces a novel way to apply physical laws directly within the learning process, optimizing the network to adhere to the principles governing ion diffusion. This is particularly advantageous for solving the partial differential equations that describe the diffusion process in 2D and 3D. By inputting the spatial distribution of ferric ions at a given time, along with boundary conditions and the diffusion coefficient, the model can backtrack to accurately reconstruct the original ion distribution. This capability is crucial for enhancing the fidelity of 3D spatial dose measurements, ensuring that the data reflect the true dose distribution without the artifacts introduced by ion migration. Here, multidimensional models able to handle 2D and 3D data were developed and tested against dose distributions numerically evolved in time from 20 to 100 h. The results in terms of various metrics show a significant agreement in both 2D and 3D dose distributions. In particular, the mean square error of the prediction spans the range 1×10-6-1×10-4, while the gamma analysis results in a 90-100% passing rate with 3%/2 mm, depending on the elapsed time, the type of distribution modeled and the dimensionality. This method could expand the applicability of Fricke gel dosimeters to a wider range of measurement tasks, from simple planar dose assessments to intricate volumetric analyses. The proposed technique holds great promise for overcoming the limitations imposed by ion diffusion in Fricke gel dosimeters.

Utilization of formic acid by extremely thermoacidophilic archaea species.

The exploration of novel hosts with the ability to assimilate formic acid, a C1 substrate that can be produced from renewable electrons and CO2, is of great relevance for developing novel and sustainable biomanufacturing platforms. Formatotrophs can use formic acid or formate as a carbon and/or reducing power source. Formatotrophy has typically been studied in neutrophilic microorganisms because formic acid toxicity increases in acidic environments below the pKa of 3.75 (25°C). Because of this toxicity challenge, utilization of formic acid as either a carbon or energy source has been largely unexplored in thermoacidophiles, species that possess the ability to produce a variety of metabolites and enzymes of high biotechnological relevance. Here we investigate the capacity of several thermoacidophilic archaea species from the Sulfolobales order to tolerate and metabolize formic acid. Metallosphaera prunae, Sulfolobus metallicus and Sulfolobus acidocaldarium were found to metabolize and grow with 1-2 mM of formic acid in batch cultivations. Formic acid was co-utilized by this species alongside physiological electron donors, including ferrous iron. To enhance formic acid utilization while maintaining aqueous concentrations below the toxicity threshold, we developed a bioreactor culturing method based on a sequential formic acid feeding strategy. By dosing small amounts of formic acid sequentially and feeding H2 as co-substrate, M. prunae could utilize a total of 16.3 mM of formic acid and grow to higher cell densities than when H2 was supplied as a sole electron donor. These results demonstrate the viability of culturing thermoacidophilic species with formic acid as an auxiliary substrate in bioreactors to obtain higher cell densities than those yielded by conventional autotrophic conditions. Our work underscores the significance of formic acid metabolism in extreme habitats and holds promise for biotechnological applications in the realm of sustainable energy production and environmental remediation.

Metagenomic analysis reveals enhanced sludge dewaterability through acidified sludge inoculation: Regulation of Fe (II) oxidation electron transport pathway

The bioleaching utilizing indigenous microbial inoculation can continuously improve the dewaterability of sludge. In this study, metagenomic analysis was innovative employed to identify the key microorganisms and functional genes that affect the dewatering performance of sludge in the bioleaching conditioning process. The results demonstrated that long-term repeated inoculation of acidified sludge resulted in increased abundance of many functional genes associated with the transport of carbohydrate and amino acid. Additionally, genes encoding key iron transport proteins (such as afuA, fhuC, and fhuD) and genes related to electron transfer carriers in ferrous iron oxidation process (such as rus and cyc2) were significantly enriched, thereby promoting the improvement of sludge dewatering performance through enhanced iron oxidation. Notably, Acidithiobacillus, Betaproteobacteria, and Hyphomicrobium were the major sources of functional genes. This study reveals the microscopic mechanisms underlying the improvement of sludge dewaterability through bioleaching based on mixed culture from a novel perspective of gene metabolism.

Evaluation of antioxidant activity, nutritional and mineral composition of Moringa (Moringa Oleifera) and Ginger (Zingiber Officinale) leaves, flowers and rhizome

Two tropical and subtropical plants that are highly prized and well-known for their rich nutritional qualities, numerous medical uses, and overall health advantages are Moringa (Moringa Oleifera) and Zinger (Zingiber Officinale). This study investigates the antioxidant activity, nutritional composition, and mineral content of Moringa Oleifera and Zingiber Officinale, focusing on their leaves, flowers, and rhizomes. Utilizing solvent extraction with ethanol and evaluated the antioxidant properties using DPPH radical scavenging and ferric reducing antioxidant power (FRAP) assays, alongside phytochemical analyses for total phenol and flavonoid content. Our results indicate that Moringa leaves exhibit superior antioxidant activity and the highest total phenol and flavonoid content, while ginger rhizome demonstrates significant ferric ion reduction capability. Nutritional analysis revealed that Moringa leaves are rich in protein, ash, and minerals, particularly calcium and iron, surpassing other plant parts and ginger samples. Conversely, ginger rhizome has higher moisture content but lower protein and mineral levels. These findings highlight the distinct health benefits and nutritional superiority of Moringa leaves, suggesting their potential as a valuable dietary supplement, particularly in addressing deficiencies in calcium and iron.

Methanogenesis coupled hydrocarbon biodegradation enhanced by ferric and sulphate ions

Bioremediation provides an environmentally sound solution for hydrocarbon removal. Although bioremediation under anoxic conditions is slow, it can be coupled with methanogenesis and is suitable for energy recovery. By altering conditions and supplementing alternative terminal electron acceptors to the system to induce syntrophic partners of the methanogens, this process can be enhanced. In this study, we investigated a hydrocarbon-degrading microbial community derived from chronically contaminated soil. Various hydrocarbon mixtures were used during our experiments in the presence of different electron acceptors. In addition, we performed whole metagenome sequencing to identify the main actors of hydrocarbon biodegradation in the samples. Our results showed that the addition of ferric ions or sulphate increased the methane yield. Furthermore, the addition of CO2, ferric ion or sulphate enhanced the biodegradation of alkanes. A significant increase in biodegradation was observed in the presence of ferric ions or sulphate in the case of all aromatic components, while naphthalene and phenanthrene degradation was also enhanced by CO2. Metagenome analysis revealed that Cellulomonas sp. is the most abundant in the presence of alkanes, while Ruminococcus and Faecalibacterium spp. are prevalent in aromatics-supplemented samples. From the recovery of 25 genomes, it was concluded that the main pathway of hydrocarbon activation was fumarate addition in both Cellulomonas, Ruminococcus and Faecalibacterium. Chloroflexota bacteria can utilise the central metabolites of aromatics biodegradation via ATP-independent benzoyl-CoA reduction.Key points• Methanogenesis and hydrocarbon biodegradation were enhanced by Fe3+ or SO42−• Cellulomonas, Ruminococcus and Faecalibacterium can be candidates for the main hydrocarbon degraders• Chloroflexota bacteria can utilise the central metabolites of aromatics degradationGraphical

MYOCD and SRF-mediated MLCK transcription prevents polymorphonuclear neutrophils from ferroptosis in sepsis-related acute lung injury.

Persistent activation of polymorphonuclear neutrophils (PMNs) plays a crucial role in the development of sepsis-related acute lung injury (ALI). This study investigated key molecular mechanisms involved in the hyperactivation of PMNs during ALI. A mouse model of sepsis-related ALI was generated by lipopolysaccharide (LPS) injection. RNA sequencing identified myosin light chain kinase (MLCK) as the most significant differentially expressed gene (DEG) between PMNs isolated from model and control mice. Myocardin (MYOCD) and serum response factor (SRF) were two of the DEGs that could promote transcription of MLCK by binding to its promoter. Either knockdown of MLCK, MYOCD, or SRF ameliorated dysfunction and edema in the lungs of LPS-treated mice. Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggested that the DEGs are enriched in a ferroptosis-related signaling pathway. The MLCK, MYOCD, or SRF knockdown increased contents of ROS, MDA, ferritin, and ferrous iron, and reduced levels of GSH and GPX4 in the PMNs. However, the MLCK overexpression restored ferroptosis resistance and activity of the PMNs, resulting in increased lung injury. Collectively, this study demonstrates that MYOCD and SRF-mediated MLCK upregulation is correlated with ferroptosis resistance and hyperactivation of PMNs in sepsis-related ALI.

Identification of key factors and mechanism determining arsenic mobilization in paddy soil-porewater-rice system

Arsenic (As) mobilization in paddy fields poses significant health risks, necessitating a thorough understanding of the controlling factors and mechanisms to safeguard human health. We conducted a comprehensive investigation of the soil-porewater-rice system throughout the rice life cycle, focusing on monitoring arsenic distribution and porewater characteristics in typical paddy field plots. Soil pH ranged from 4.79 to 7.98, while porewater pH was weakly alkaline, varying from 7.2 to 7.47. Total arsenic content in paddy soils ranged from 6.8 to 17.2 mg/kg, with arsenic concentrations in porewater during rice growth ranging from 2.97 to 14.85 μg/L. Specifically, arsenite concentrations in porewater ranged from 0.48 to 7.91 μg/L, and arsenate concentrations ranged from 0.73 to 5.83 μg/L. Through principal component analysis (PCA) and analysis of redox factors, we identified that arsenic concentration in porewater is predominantly influenced by the interplay of reduction and desorption processes, contributing 43.5 % collectively. Specifically, the reductive dissolution of iron oxides associated with organic carbon accounted for 23.3 % of arsenic concentration dynamics in porewater. Additionally, arsenic release from the soil followed a sequence starting with nitrate reduction, followed by ferric ion reduction, and subsequently sulfate reduction. Our findings provide valuable insights into the mechanisms governing arsenic mobilization within the paddy soil-porewater-rice system. These insights could inform strategies for irrigation management aimed at mitigating arsenic toxicity and associated health risks.

Enhancing anaerobic ammonium oxidation via polymeric ferric sulfate (PFS)-Mediated dual-electron Acceptor: A solution to nitrite deficiency

In addressing the issue of the unstable supply of electron acceptors (nitrite) during Anammox, researchers have often overlooked that the electron transfer process in anammox bacteria (AnAOB) is not restricted to the intracellular, extracellular electron transfer can also serve as an alternative pathway. This study utilized Fe3+ as an adjunctive electron acceptor, coupling Anammox with ferric iron reduction (Feammox) by introducing polymeric ferric sulfate (PFS) in the Anammox system. This approach achieved effective nitrogen removal even when nitrite was deficient. At a NO2–-N to NH4+-N ratio of 0.5, the Feammox-Anammox combined system maintained stable nitrogen removal under the dual electron acceptor, with total nitrogen and NH4+-N removal efficiency of 85 % and 91 %, respectively. The contribution of Feammox and Anammox to NH4+-N removal was 45 % and 55 %, respectively. TEM-EDS confirmed the presence of iron elements across the periphery, periplasm, and cytoplasm of AnAOB, suggesting the involvement of PFS in the metabolic and electron transfer processes. Notably, the introduction of Fe3+ and the limitation of nitrite availability resulted in increased relative abundances of FeOB (Thermomonas) and FeRB (Ignavibacterium) to 30 % and 3.6 %, respectively, indicating that the electron transfer process with Fe3+ as the electron acceptor was continuously intensified, as well as a cycle of Fe3+ / Fe2+ was established. Due to unique nitrogen metabolism mode and high Fe3+ tolerance, the abundance of Candidatus_Brocadia was enriched up to 7.2 %, which alternately dominated the Anammox process with Candidatus_Kuenenia, providing favorable conditions for AnAOB to carry out the extracellular electron transfer process. These findings provide a novel strategy for improving the stability and efficiency of the Anammox process under deficient nitrite supply.

Isopropyl 3-(3,4-Dihydroxyphenyl)-2-hydroxypropanoate Alleviates Palmitic Acid-Induced Vascular Aging in HUVEC Cells through ROS/Ferroptosis Pathway.

Vascular aging is an important factor leading to cardiovascular diseases such as hypertension and atherosclerosis. Hyperlipidemia or fat accumulation may play an important role in vascular aging and cardiovascular disease. Isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate (IDHP) has biological activity and can exert cardiovascular protection, which may be related to ferroptosis. However, the exact mechanism remains undefined. We hypothesized that IDHP may have a protective effect on blood vessels by regulating vascular aging caused by hyperlipidemia or vascular wall fat accumulation. The aim of this study is to investigate the protective effect and mechanism of IDHP on palmitic acid-induced human umbilical vein endothelial cells (HUVEC) based on senescence and ferroptosis. We found that IDHP could delay vascular aging, reduce the degree of ferrous ion accumulation and lipid peroxidation, and protect vascular cells from injury. These effects may be achieved by attenuating excessive reactive oxygen species (ROS) and ferroptosis signaling pathways generated in vascular endothelial cells. In short, our study identified IDHP as one of the antioxidant agents to slow down lipotoxicity-induced vascular senescence through the ROS/ferroptosis pathway. IDHP has new medicinal value and provides a new therapeutic idea for delaying vascular aging in patients with dyslipidemia.

HCl-induced emulsion and sludge formation affected by asphaltene type

Asphaltene may cause severe challenges during acid stimulation of oil wells. In the course of contact between crude oil and the injected acid (i.e. HCl), dispersed asphaltene molecules in the organic medium chemically adsorb and accumulate onto the surface of acid droplets due to interaction with acid ions. This causes forming a shear-resistance interfacial layer, known as acid-induced sludge, that prevents droplet coalescence and stabilizes the unwanted acid in oil emulsion. In this study, a set of compatibility tests was conducted to discern the emulsion stabilizing affinity of various asphaltene samples and sludge formation as a function of experimental variables including acid-to-mixture volumetric ratio (AMR) and pH, ferric ion, and asphaltene concentrations, aromaticity of the model oil, and shear (mixing speed). The utilization of heptol model oils (a mixture of heptane, toluene, and asphaltene) would help to focus on asphaltene behavior while isolating the other crude oil components. Five asphaltene samples (A1 to A5) having different structures were used in this study. Regardless of asphaltene properties, the emulsion stability was decreased approximately 70 % by increasing AMR. In addition, more aromaticity of the model oil resulted in 80 % less emulsion stability. There is a minimum range for emulsion stability in the interval of 500–1000 ppm asphaltene concentration for all samples. Up to 50 % emulsion stability was detected in the case of asphaltene A3 because of basic properties and higher colloidal instability. The effect of ferric ion concentration on intensifying emulsion stability and sludge formation was noticeable up to 500 ppm. HCl-model oil emulsion and the formed sludge had no sensitivity to shear force in the range of 500–1500 rpm due to the very low viscosity of the model oil. Therefore, in the studied shear range, emulsion and sludge formation have been more chemically controlled instead of being physically limited due to mixing. Moreover, sludge formation is not affected by pH of the HCl solution higher than 2 and mixing speed.

The effect of iron status on gadolinium deposition in the rat brain: mechanistic implications.

Introduction: Sites associated with gadolinium (Gd) deposition in the brain (e.g., the globus pallidus) are known to contain high concentrations of ferric iron. There is considerable debate over the mechanism of Gd deposition in the brain. The role of iron transport mechanisms in Gd deposition has not been determined. Thus, we seek to identify if Gd deposition can be controlled by modifying iron exposure. Methods: Female Sprague-Dawley rats were given diets with controlled iron levels at 2-6ppm, 6ppt (20g/kg Fe carbonyl) or 48ppm for 3weeks to induce iron deficiency, overload or normalcy. They were kept on those diets while receiving a cumulative 10mmol/kg dose of gadodiamide intravenously over 2weeks, then left to washout gadodiamide for 3days or 3weeks before tissues were harvested. Gd concentrations in tissues were analyzed by ICP-MS. Results: There were no significant effect of dietary iron and total Gd concentrations in the organs, but there was a significant effect of iron status on Gd distribution in the brain. For the 3-week washout cohort, there was a non-significant trend of increasing total brain deposition and decreasing dietary iron, and about 4-fold more Gd in the olfactory bulbs of the low iron group compared to the other groups. Significant brain accumulation was observed in the low iron group total brain Gd in the 3-week washout group relative to the 3-day washout group and no accumulation was observed in other tissues. There was a strong negative correlation between femur Gd concentrations and concentrations in other organs when stratifying by dietary iron. Discussion: Gd brain deposition from linear Gd-based contrast agents (GBCAs) are dependent upon iron status, likely through variable transferrin saturation. This iron dependence appears to be associated with redistribution of peripheral deposited Gd (e.g., in the bone) into the brain.

Rapid microwave fabrication of highly luminescent nitrogen and phosphorous co-doped carbon quantum dots for the determination of glutathione in pharmaceutical supplements

A facile and sensitive nano-probe for spectrofluorometric glutathione (GSH) determination has been developed based on dual-doped nitrogen and phosphorus carbon quantum dots (NP@CQDs). The NP@CQDs were prepared, through a rapid, one-step microwave heating method in only 180 s with a high quantum yield (0.63) using ethylenediaminetetraacetic acid as carbon and nitrogen precursor and diammonium hydrogen phosphate as nitrogen and phosphorus dopant. The synthesised NP@CQDs had a maximum bluish fluorescence emission at 420 nm, after excitation at 360 nm. The luminescence of the prepared NP@CQDs was quenched via a static quenching mechanism by ferrous ions, while ferric ions did not affect the emission of NP@CQDs. GSH was mixed with ferric ions before adding NP@CQDs to exploit this observation. The attenuation in emission observed after adding NP@CQDs to GSH/ferric ions was directly related to the GSH concentration, as GSH worked to reduce the ferric ions present and produce ferrous ions. The proposed fluorometric method was validated in compliance with the International Council on Harmonization (ICH) guidelines. The proposed fluorescent nano-probe showed good linearity for GSH determination over a range of 0.5–10 µg/mL with % recoveries ranging between 99.50 and 101.86 %, and RSD less than 2 %. NP@CQDs were implemented for GSH determination in pharmaceutical supplementary capsules with respectable accuracy and precision. This approach is simple, reliable, accurate, specific, and it also does not require expensive chemicals or sophisticated equipment. This work opens up other uses of NP@CQDs in pharmaceutical and environmental analysis.

Crafting and analyzing nonwovens enhanced with antimicrobial metal particles and diverse mechanisms via substitution reaction

Bacterial infections result in serious impacts on human health. Non-toxic, potent, and flexible antimicrobial particles loaded onto nonwoven materials offer a promising solution. Metallic antimicrobial particles have achieved significant attention and application; however, common materials such as silver and copper exhibit potential toxicity and typically employ a singular antimicrobial mechanism. This limitation can diminish their effectiveness over the service cycle. In our research gallium (Ga), known for its activity and versatile antimicrobial mechanisms, was employed with ferrous ions (Fe2+), which offer broad-spectrum antimicrobial properties and lower potential toxicity compared to silver and copper. Through spontaneous substitution reaction. Ga and Fe2+ can generate Ga–Fe alloys and various antimicrobial particles. In this study, we developed antimicrobial nonwovens by loading them with multiple types of metal antimicrobial particles through a simple soaking and surface treatment process. The multifaceted antimicrobial mechanisms introduced by these multiple particles provide the nonwoven materials with exceptional antimicrobial performance, achieving an effectiveness of up to 99.99 % against Escherichia coli and Staphylococcus aureus. The feasibility of the substitution reaction between Ga and Fe2+ was thoroughly verified through theoretical calculations, X-ray photoelectron spectroscopy (XPS) characterization, and experimental observations. This research offers valuable insights for advancing and exploring antimicrobial nonwoven materials.

Copper leaching behaviour during oxygen pressure leaching of zinc sulfide concentrate

ABSTRACT To optimise copper (Cu) leaching, this study investigated Cu behaviour during a two-stage oxygen pressure leaching process of zinc sulfide concentrate (ZnS). The results indicated that maintaining low temperature, low sulfuric acid (H2SO4) concentration, and low oxygen partial pressure during the first stage of leaching the reduction of ferric iron (Fe3+) by ZnS and the weak leaching of Cu. In the second stage, increasing the temperature, H2SO4 concentration, and oxygen partial pressure enabled efficient Cu leaching while converting iron (Fe) back to Fe3+ and returning it to the first stage. This two-stage process effectively mitigated Fe hydrolysis precipitation, resulting in a small residue yield and preventing Cu incorporation into jarosite. Cyclic validation experiments were conducted under optimum experimental conditions with a residue yield of 36.1%, the dissolution rates of Zn, Cu, and Fe impurity of 98.76%, 91.65%, and 81.05%, and the Zn, Cu, and silver (Ag) contents of leaching residue were 1.61%, 0.17%, and 0.524%, respectively. The primary phases in the leach residue included lead (Pb) sulfate, sulfur, and pyrite. This approach allowed for deep leaching of Zn and Cu as well as achieving efficient Pb and Ag enrichment.

Benzothieno[c]quinoline based a novel fluorescent “turn-on” chemosensor for the detection of Fe (III) from aqueous solution

A 6-(thiophen-2-yl)benzo[4,5]thieno[3,2-c]quinoline (QTP), with thiophene and quinoline based moieties as binding sites, has been synthesized and characterized with spectroscopic methods, and DFT. The synthesized probe QTP showed highly sensitive and highly specific fluorescent ‘turn-on’ effect (λem = 280 nm) for the 1:1 binding with Fe3+ ions to form probe QTP.Fe3+ complex in semi-aqueous medium (acetonitrile:water (50:50; v/v)) and live cells. The 1:1 binding stoichiometry of probe QTP and Fe3+ ions were proposed by DFT calculations and confirmed by the NMR spectroscopy, and mass spectrum of probe QTP.Fe3+ complex. Importantly, with the LOD 6.37 µM for the detection of Fe3+ ions, receptor QTP did not show any interference from potentially competing ions, indicates its biocompatibility. The micromolar limit of detection (6.37 µM), cell permeability, and low cytotoxicity allows the probe QTP to be an outstanding tool for the live-cell imaging and detection of ferric ions in live cells.

Aerobic Fe transformation induced decrease in the adsorption and enhancement in the reduction of Cr(VI) by humic acid-ferric iron coprecipitates

Humic substance (HS)-ferric iron (Fe(III)) coprecipitates are widespread organo-mineral associations in soils and aquifers and have the capacity to immobilize and detoxify Cr(VI). These coprecipitates undergo transformation owing to their thermodynamic instability; however, the effects of this transformation on their environmental behaviors remain unclear, particularly in aerobic environments. In this study, the aerobic transformation of humic acid (HA)-Fe(III) coprecipitates, a representative of HS-Fe(III) coprecipitates, was simulated. The environmental effect was then evaluated after conducting an adsorption–reduction batch experiment toward Cr(VI). The aerobic transformation characteristics, as well as the adsorption/reduction capacity of HA-Fe(III) coprecipitates, were found to depend strongly on their structures. In ferrihydrite (Fh)-like coprecipitates, amorphous Fh is readily transformed into crystalline hematite and goethite at aerobic environments, leading to a much lower specific surface area and adsorption capacity. However, this increasing degree of crystallization enhanced the inductive reduction ability towards Cr(VI) owing to the more significant shift of electron pairs in the FeOC bond toward the HA direction. In HS-like coprecipitates, Fe(III) always serves as a cation bridge connecting HA molecules, but can be reduced to Fe(II) by the associated HA after aerobic transformation. The produced Fe(II), therefore, drove the reduction of the adsorbed Cr(VI). These findings emphasize the pivotal role of aerobic transformation in enhancing the reduction capacity for Cr(VI), which opens a new avenue for the development of in-situ remediation agents for Cr(VI)-contaminated sites.

Avicularin Attenuated Lead-Induced Ferroptosis, Neuroinflammation, and Memory Impairment in Mice.

Lead (Pb) is a common environmental neurotoxicant that results in abnormal neurobehavior and impaired memory. Avicularin (AVL), the main dietary flavonoid found in several plants and fruits, exhibits neuroprotective and hepatoprotective properties. In the present study, the effects of AVL on Pb-induced neurotoxicity were evaluated using ICR mice to investigate the molecular mechanisms behind its protective effects. Our study has demonstrated that AVL treatment significantly ameliorated memory impairment induced by lead (Pb). Furthermore, AVL mitigated Pb-triggered neuroinflammation, ferroptosis, and oxidative stress. The inhibition of Pb-induced oxidative stress in the brain by AVL was evidenced by the reduction in malondialdehyde (MDA) levels and the enhancement of glutathione (GSH) and glutathione peroxidase (GPx) activities. Additionally, in the context of lead-induced neurotoxicity, AVL mitigated ferroptosis by increasing the expression of GPX4 and reducing ferrous iron levels (Fe2+). AVL increased the activities of glycogenolysis rate-limiting enzymes HK, PK, and PYG. Additionally, AVL downregulated TNF-α and IL-1β expression while concurrently enhancing the activations of AMPK, Nrf2, HO-1, NQO1, PSD-95, SNAP-25, CaMKII, and CREB in the brains of mice. The findings from this study suggest that AVL mitigates the memory impairment induced by Pb, which is associated with the AMPK/Nrf2 pathway and ferroptosis.

CRISPR/dCas12a knock-down of Acidithiobacillus ferrooxidans electron transport chain bc1 complexes enables enhanced metal sulfide bioleaching

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 knockdown 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.

Magnesium hexacyanoferrate nanocatalysts alleviates fibromyalgia syndrome by reversing cellular ferroptosis

Fibromyalgia (FM), the most common causes of chronic musculoskeletal pain, is a complex syndrome with an indefinite etiology. Ferroptosis is a new type of cell death characterized by iron-dependent lipid peroxidation, affecting many chronic pain diseases. Here, we confirmed the role of ferroptosis in FM using a mouse model of reserpine induction. Then, we developed polyvinylpyrrolidone-assembled magnesium hexacyanoferrate nanocatalysts (MgHCF NCs) as a new type of ferroptosis inhibitor, for its efficacy in ferrous ions capture and antioxidation. Excellent in vivo FM-alleviation effect from MgHCF NCs was demonstrated. The FM-protective and antiferroptotic efficacy of MgHCF NCs at the transcriptional level were explored by whole-transcriptome analysis. Meanwhile, the remarkable antiferroptotic effect of MgHCF NCs was further validated in vitro ferroptosis-inducer experiments, which was firmly associated with the efficacy of MgHCF NCs on reducing oxidative stress, mitochondrial protection and correcting disordered polyunsaturated fatty acids (PUFAs) metabolism. The excellent antiferroptotic effect and biocompatibility render MgHCF NCs to be highly promising and clinically transformable agents for FM treatment.