Fe Increase Research Articles

Effect of Fe2+ on ANAMMOX Granular Sludge Cultured in a Biased Acidic Influent and Dynamic Environment

A continuous stirred tank reactor (CSTR) was utilized in this study to enrich and cultivate anaerobic ammonia oxidation process (ANAMMOX) granular sludge by gradually decreasing its pH, and to investigate the effects of different concentrations of ferrous ions (Fe2+) on the activity of ANAMMOX granular sludge cultivated under biased acidic conditions. The final nitrogen removal of ANAMMOX deteriorated at pH 6.30–6.50 after 220 days of continuous operation, but the nitrogen removal of ANAMMOX was favorable at pH 6.50–7.00. This indicates that a slightly acidic environment (pH = 6.50–7.00) promotes the activity of ANAMMOX, but the pH should not be too low (pH = 6.30–6.50). In the reactor, Candidatus Kuenenia was consistently the dominant ANAMMOX genus and its abundance declined from 11.70% on day 1 to 10.44% on day 220. As Fe2+ concentrations were increased (10, 20, 30 mg/L) in ANAMMOX granular sludge cultured in an acidic environment, the nitrogen removal effects gradually increased. In addition, with the increase in Fe2+ concentrations, the total nitrogen removal load (NRL) in the reactor was increased from 1.16 kg/(m3/d) to 1.42 kg/(m3/d). Increases in Fe2+ concentration did not result in inhibition of ANAMMOX, which may be attributed to the morphology of sludge and the shape of the reactor. As a result of the present study, new insights were gained into the physiological characteristics of ANAMMOX in an acidic environment over the long term, and how Fe2+ affects its ability to remove nitrogen from the environment.

Rape Straw Biochar Application Enhances Cadmium Immobilization by Promoting Formation of Sulfide and Poorly Crystallized Fe Oxide in Paddy Soils

The mechanisms of rape straw biochar that affect the fixation of cadmium (Cd) in paddy soil by influencing redox of iron and sulfur are unclear. Several anaerobic incubation experiments were carried out using Cd-contaminated paddy soils (LY and ZZ). Rape straw biochar at pyrolysis temperatures of 450 °C (LRSB) and 800 °C (HRSB) was selected as the soil remediation agent. The electron exchange capacity and electrical conductivity were higher in HRSB than those in LRSB. The lower pe + pH in HRSB enhanced Fe oxide reduction, with a maximum increase in Fe2+ of 46.0% in ZZ. Compared to treatment without biochar (CK), the poorly crystallized Fe oxide (Feo) in HRSB increased by 16.8% in ZZ. This induced Cd bound to Fe, and Mn oxides fraction (Fe-Mn Cd) increased by 42.5%. The SO42−-S content in LRSB was 4.6 times that of HRSB. LRSB addition increased acid-volatile sulfide by 46.4% and 48.9% in LY and ZZ soils, respectively, compared to CK. This resulted in an increase in sulfide’s contribution to Cd fixation, with values rising from 24.2% to 37.8% in LY and 19.1% to 29.8% in ZZ. Overall, LRSB reduced Cd mobility by forming more sulfide, while HRSB increased Fe-Mn Cd by increasing Feo.

In situ simultaneous Fe K-edge XAS spectroscopy and resistivity measurements of riebeckite: Implications for anomalous electrical conductivity in subduction zones

In this paper, we address two key features of the behaviour of Fe-rich amphibole at high temperatures: (1) the Fe2+ → Fe3+ + e− exchange within the crystal bulk, and (2) the consequent rise in electrical conductivity. Cycling heating-cooling experiments were done in situ up to 542 °C (815 K) at beamline B11 of the Diamond Synchrotron Laboratory (UK). X-ray absorption spectra at the Fe K-edge and electrical resistivity were measured simultaneously on a single crystal of riebeckite with a composition very close to the ideal formula A□BNa2C(Fe2+3Fe3+2)TSi8O22W(OH)2. The Fe3+/Fetot ratio was monitored via analysis of the pre-edge feature in the XANES spectra. Our data show slight oscillations of the oxidation state of Fe with temperature cycling up to around 400 °C (673 K), followed by a substantial gradual increase in Fe2+ → Fe3+ oxidation that starts at ~450 °C (~723 K) and is completed at ~525 °C (~798 K). The conductivity (σ) measured along the crystallographic c-axis oscillates strongly with cycling temperature allowing us to conclude that it is intrinsically related to the electron hopping induced by thermal treatment. The activation-energy derived from the σ(T) trend is Ea = 74.4 ± 0.6 kJ/mol (0.77 ± 0.01 eV), in agreement with small-polaron conduction. This study provides direct and robust support of the conduction mechanisms in Fe-amphibole previously inferred from indirect methods. Given that riebeckite is a significant component in the glaucophanitic amphiboles common in blueschists associated with subducted oceanic crust, our data provide a link between atomic-scale processes and Earth-scale anomalous conductivity observed via geophysical measurements.

Structure and properties of fiber-reinforced LiZn ferrite ceramics prepared via spark plasma sintering

In order to improve the matrix cracking of LiZn ferrite (LZF) ceramics during spark plasma sintering, fiber-reinforced LZF materials were prepared using silicon carbide nanofibers (SCFs) and alumina whiskers (AWs) as reinforcement phases. The effect of fiber reinforcement on the microstructure and mechanical, electrical, and magnetic properties of LZF was systematically studied. The results reveal that SCFs lead to an increase in grain size of SCF-reinforced LiZn ferrites (LZF-S) and a deterioration of grain morphology due to the transgranular behavior of SCFs. The increase in complex dielectric constant and dielectric loss, as well as the decrease in resistance of LZF-S, is due to the increase in Fe2+ concentration in ceramics and low resistance of SCFs. AW-reinforced LiZn ferrites (LZF-A) show the opposite effect due to the high porosity caused by AWs and the high resistance of AWs. LZF-S exhibits high fiber/matrix bonding strength, which permits the transfer of the load from the matrix to the fiber to be more effective, leading to a high fracture toughness (KIC) of 5.1 MPa m1/2. The bonding strength between fiber and matrix of LZF-A is low, but a large number of pores passivate the crack tip. At an SCF content of less than 2.5 wt%, the saturation magnetization (Ms) of LZF does not decrease obviously, but a small amount of AWs leads to a significant decrease in Ms (pure LZF: 83 emu·g−1; 1.0 wt% SCFs: 80 emu·g−1; 1.0 wt% AWs: 62 emu·g−1), which can be ascribed to the partial substitution of Fe3+ by nonmagnetic Al3+ ions. When the content of reinforcement phases is 1 wt%, the ferroresonance linewidth increases significantly due to the high porosity caused by the secondary phases (pure LZF: 234 Oe; 1.0 wt% SCFs: 2161 Oe; 1.0 wt% AWs: 1020 Oe).

Hydrological and Geological Controls for the Depth Distribution of Dissolved Oxygen and Iron in Silicate Catchments

AbstractDissolved Oxygen (DO) plays a key role in reactive processes and microbial dynamics in the critical zone. Recent observations showed that fractures can provide rapid pathways for oxygen penetration in aquifers, triggering unexpected biogeochemical processes. In the shallow subsurface, DO reacts with electron donors, such as Fe2+ coming from mineral dissolution. Yet, little is known about the factors controlling the spatial heterogeneity and distribution of oxygen with depth. Here we present a reduced analytical model describing the coupled evolution of DO and Fe2+ as a function of fluid travel time in silicate catchments. Our model, validated from fully resolved reactive transport simulations, predicts a linear decay of DO with time, followed by a rapid non‐linear increase of Fe2+ concentrations up to a far‐from‐equilibrium steady‐state. The relative effects of geological and hydrological forcings are quantified through a Damköhler number (Da) and a lithological number (Λ). We use this framework to investigate the depth distribution of DO and Fe2+ in two catchments with similar environmental contexts but contrasted hydrochemical properties. We show that hydrochemical differences are explained by small variations in Da but orders of magnitude variations in Λ. Therefore, we demonstrate that the hydrological and geological drivers controlling hydrochemistry in silicate catchments can be discriminated by analyzing jointly the O2 and Fe2+ evolution with depth. These findings provide a new conceptual framework to understand and predict the evolution of DO in modern groundwater, which plays an important role in critical zone processes.

Multiferroic properties of Ba2+-Ti4+ co-doped YFeO3 ceramics

The search for multiferroic materials with ferroelectric and ferromagnetic properties at room temperature continues to be driven by the prospect of new devices. In this paper, Ba2+-Ti4+ co-doped Y1-x(Ba0.5Ti0.5)xFeO3 were prepared by a traditional solid-state reaction method. The ferroelectricity and ferromagnetism of the co-doped ceramics have been enhanced simultaneously with the maximum polarization of 0.48 μC/cm2 and the maximum magnetization of 3.25 emu/g, the switched charge density (0.26 μC/cm2) measured by PUND tests indicating the intrinsic and switchable remanent polarization. The increase of Fe2+ content (increased to 28 % with the increase of doping content) caused by Ba2+-Ti4+ co-doping destroys the antiferromagnetic ground state, and the doping strategy enlarges the tilt angle of oxygen octahedron from 144.93° to 148.63°. The magnetic domain switches caused by the external electric field were directly observed by magnetic force microscopy, indicating the modulation of magnetic domain by polarization at room temperature. This work may provide useful information for the structural design and performance improvement of multiferroic materials.

Enhancing catalytic performance of red mud for palmitic acid hydrodeoxygenation by acid pretreatment-induced structural modification

Red mud (RM) is a metal oxide-enriched solid waste material that was subjected to various acid treatments to assess their effect on catalytic performance for hydrodeoxygenation (HDO). Acid pretreatment induces structural changes in RM, which enhances its stability and catalytic performance for HDO. Among the different acid treatments, acetic acid-treated RM catalyst (Ni/RM-HAC) exhibited superior catalytic performance and stability, yielding 81% cetane selectivity and maintaining efficient conversion for up to 400 h. The acetic acid treatment increased the Fe2O3 content in the catalyst, removed inert components such as Na2O and CaO that block pore channels, and greatly improved specific surface area and pore size. Moreover, the acetic acid treatment increased medium acid sites and oxygen vacancy in the catalyst, enhancing its catalytic performance. The increase of Fe3+ makes the catalyst have better stability. These results are expected to aid in the development of efficient, sustainable, and cost-effective catalysts for the production of the second-generation biodiesel.

Experimental and theoretical study on La0.5K0.5Mn1−xFexO3 perovskite catalysts for mild temperature soot combustion and simultaneous removal of soot and NO

In order to control high emissions of soot and NOx from diesel engines, this research utilizes highly efficient perovskite oxide catalysts to simultaneously remove soot and NO. A series of La0.5K0.5Mn1-xFexO3 catalysts were prepared by citric acid complexation method, and the active sites and structure stability of LaMnO3 perovskite catalyst were investigated according to the first principle. Research results show that K+ doping causes the transformation of Mn3+ into Mn4+ in LaMnO3 catalyst system and forms more oxygen vacancies. Meanwhile, Fe3+ doping leads to the octahedron distortion of MnO6 and FeO6 in catalyst system, which enhances the stability of catalyst structure. The oxygen vacancy formed by doping K+ and Fe3+ accelerates the migration rate of lattice oxygen and improves the catalytic activity of perovskite catalyst for soot oxidation. With the increase of Fe3+ doping, the proportion of adsorbed oxygen and high valence active ions in catalyst system increases. Moreover, the alkaline sites on the catalyst surface are favorable for the adsorption of acid gas NO. The La0.5K0.5Mn0.67Fe0.33O3 catalyst has the highest catalytic activity, the ignition temperature of soot oxidation drops to 291 °C, and CO2 selectivity exceeds 99.9%. At 370 °C, the conversion rate of NO reaches the maximum value of 61.7%.

δ18O and δ2H isotopes, trace metals and major ions in groundwater around uranium and fluoride contaminated Indus valley Quaternary alluvial plain, SW Punjab, India: Implications on hydrogeochemical processes, irrigation use and source

Uranium and fluoride enrichment in groundwater along alluvial plains pose a severe threat to living beings like cancer, fluorosis and crop yield as witnessed around semi-arid southwest Punjab, India. In-situ groundwater was examined for major ions, stable isotopes and trace metals to understand the hydrogeochemical processes, contaminant origin and health risks around SW Punjab, India. Groundwater from a freshly drilled bore well is found to be hard, alkaline, and saline with total dissolved solids and salinity up to 1300 and 1500 mg L−1, respectively. Fluoride (up to 4 mg L−1) and uranium (up to 90.07 μg L−1) contents exceed permissible limits in most samples and originated from fertilizer inputs and aquifer leaching. Uranium contents decline with depth, while fluoride remains invariable. Decreased U contents are inferred to be caused by U(VI) reduction to U(IV) as evidenced by an increase in Fe2+ vs. Fe3+, S2− vs. S6+ and N3− vs. N5+ with depth. NaHCO3, NaCl + NaHCO3 and NaCl are the dominant water types for shallow (<38 m), intermediate (49–83 m) and deeper groundwater (105–128 m) with Na+ and HCO3− as the dominant cations and anions, respectively. Silicate weathering majorly controlled the groundwater geochemistry together with a partial contribution from cation exchange processes. Unsuitability for drinking and irrigation use is envisaged for all depths, while deeper groundwater is safe in regard to radiological risk. δ18O and δD variations are suggestive of evaporation dominance in shallow groundwater, while intermediate groundwater witness canal and groundwater mixing and deeper groundwater are recharged through higher altitude.

Abstract 1388: Non-thermal plasma-activated medium induces ferroptotic cell death by intracellular ferrous iron overload in head and neck cancer

Abstract The notoriously high proliferation rate of cancer cells requires them to constantly deal with the balance adjustment between oxidative stress overload and upregulated protective antioxidant pathways. It puts them in a vulnerable state whenever one piece of this puzzle went out of control. Non-thermal plasma (NTP) is partially ionized gas operated at or around body temperature and has emerged as a new potential anti-cancer therapy due to its ability to release and induce ROS, RNS, and other free radicals as well as generate UV- photon and electromagnetic field; but the specific mechanism and its specificity to cancer cell are still controversial. Using transcriptomic analysis, we previously reported the link between NTP-activated media (NTPAM)and apoptosis; but the sequencing data also revealed a strong Ferroptotic response in all the 6Head and Neck cancer cell lines we checked. Ferroptosis is a newly identified oxidative-regulated cell death, characterized by the iron-dependent generation of lipid peroxidation. In this study, we found the prolonged treatment of NTPAM-induced cell death via the non-canonical ferroptosis pathway by directly increasing intracellular toxic ferrous Iron (Fe2+). We found that the excessive overexpression of HMOX1 under prolonged NTPAM-induced oxidative stress was actually responsible for the surge of intracellular Fe2+ due to the increase of heme degradation. Pharmacological inhibition or RNA silencing of HMOX1 was able to rescue 2 HNC cell lines from NTPAM-induced increased Iron concentration as well as ferroptosis cell death, both in vivo and in vitro. These results suggest NTP directly induces ferroptosis via an increase of Fe2+ concentration by triggering the over-responding of the NRF2 - HMOX1 antioxidant system. This finding could be exploited to develop future NTP-based cancer therapy as well as in combination with other Iron sensitive anti-neoplastic agents; and could be a potential method of overcoming conventional cancer treatment resistance. Citation Format: QuocKhanh Nguyen, Chan Oh, Seung-Nam Jung, Yudan Piao, Mi Ae Lim, Young Il Kim, Yanli Jin, Hae Jong Kim, Bon Seok Koo. Non-thermal plasma-activated medium induces ferroptotic cell death by intracellular ferrous iron overload in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1388.

Impact of clayey sediment compaction on pore water evolution and the release of iron

The groundwater contaminants caused by the clayey sediment compaction have been reported in numerous groundwater overextraction regions. But little is known about the impact of compaction on the evolution of pore water compacted from the clayey sediments. In this study, we collected clayey sediments and conducted a low-pressure indoor experiment to identify the pore water evolution and iron releasing mechanism. Pressure demonstrates a significant influence on the release and mobilization of iron in pore water and clayey sediments. Initially, Fe2+ concentration depletion in pore water is regulated by the reduction of Fe(III) (oxy) hydroxides and precipitation with S(-II) producing Fe–S phases. Subsequently, the increase of Fe2+ with the increased pressure is attributed to the transformation of FeS to FeS2. In the final stage of the pressure experiment, more formation of FeS2 and dissolution of siderite result in the fluctuation of Fe. In addition, a release of the trace metals (Fe, Mn, Cr, Cu, Ni and Zn) detected in pore water can be what creates a potential contaminant threat in the adjacent aquifers. The compaction of the clayey sediments results in a decrease of the water content and releases the pore water into the adjacent aquifers. This study reveals the pore water evolution, highlights the complex biogeochemical reactions of iron during clayey sediments compaction and reinforces the importance of clayey sediments compaction for the aquifers water quality.

Effects of flood inundation on biogeochemical processes in groundwater during riverbank filtration

Well fields along rivers withdrawing groundwater through riverbank filtration (RBF) are popular for urban water supply, due to their good performance in assurance for both water quantity and quality. However, RBF sites are susceptible to flood inundation, which has been found to cause increase of N, Fe, and Mn contents in groundwater and threatens water safety, but the geochemical processes have not been fully understood. To bridge this gap, in situ monitoring of hydrodynamics, hydrochemistry, and stable isotopes for river water and groundwater were employed in a RBF site, NE China, to investigate into the geochemical processes in groundwater in RBF sites under long-term inundation. The results indicated that during long-term inundation, recharge from river water increased significantly, and a large amount of O2, NO3− and organic carbon (OC) from oxidizing river water could recharge far-shore groundwater vertically, whereas less NH4+ were input from regional groundwater, leading to a high content of NO3− and low content of the NH4+ in the groundwater. Meanwhile, limited NH4+ would be produced through dissimilatory nitrate reduction to ammonium (DNRA) and mineralization of organic nitrogen (MON). Moreover, along the infiltration path, aerobic respiration and denitrification (DNF) occurred rapidly. CO2 generated from OC oxidization in the two processes enhanced the dissolution of carbonate minerals, which could be used to trace the oxidizing-reducing (O-R) interface between river water and groundwater. As indicated, the inundation can cause the O-R interface which usually distributed near shore to extend to the entire well field during inundation. In this situation, the redox condition of groundwater used to be suitable for SO42− reduction in non-inundation period decreases to the level favoring the reduction of Mn(IV)/Fe(III) oxides during inundation, and the process of Fe2+ precipitation by reacting with HS− is weaken as the inhabitation of SO42− reduction, leading to a significant increase in Fe2+, Mn2+, and As contents, putting well field groundwater at risk of contamination.

QiLing Decoction promotes ferroptosis of castration-resistant prostate cancer cells by inhibiting FSP1 in vitro and in vivo.

QiLing Decoction (QLD) showed therapeutic effects against prostate cancer with an unclear underlying mechanism. This study explored the underlying mechanisms of QLD against castration-resistant prostate cancer (CRPC). Clinical specimens were collected from the patients with CRPC. Stable cells including knockdown and overexpression cell lines were established by plasmid transfection. The xenograft animal model was constructed. Cell viability was determined by using cell-counting kit 8 assay. Biochemical assays were used to determine the levels of iron (Fe2+) and lipid reactive oxygen species (ROS). qRT-PCR and Western blotting were used to determine levels of target genes, respectively. Treatment of QLD inhibited ferroptosis suppressor protein (FSP) 1 at mRNA and protein levels in patients with CRPC. Additionally, cells treated with QLD-containing serum displayed a decrease in cell viability and an increase in Fe2+ and lipid ROS with or without erastin, whereas ferroptosis inhibitor reversed QLD-induced ferroptosis. The regulatory effects of QLD on PC3 cell ferroptosis were associated with its inhibitory effects against FSP1. Consistently, QLD inhibited PC3 tumor growth by inhibiting FSP1. Moreover, treatment of QLD increased the sensitivity of PC3-AbiR cells to abiraterone by inhibiting FSP1. QLD promoted ferroptosis in CRPC cells in part by inhibiting FSP1 in vitro and in vivo.

Study on the Influence of Metal Ions on the Dispersion of Fine Calcium Gangue Minerals.

In this study, the calcium gangue material calcite (-10 μm) was used to investigate the effects of different kinds of metal ions and dosages on the dispersion behavior of calcite. The test results showed that the dispersion behavior of calcite was poor under strongly alkaline conditions without the addition of metal ions, and the reason for that was calcite dissolved ions. The degree of influence of different metal ions on calcite dispersion behavior was Fe3+ &gt; Mg2+ &gt; Na+. The three metal ion dosage tests showed that the dispersion behavior of calcite became poorer with the increase of metal ion dosage. This mainly showed that with the increase of Na+ dosage, the trend of the dispersion behavior of calcite was not obvious, but with the increase of Fe3+ and Mg2+ dosage, the trend of calcite dispersion behavior changed more. The dispersion behavior of calcite was devastated by 5 × 10-4 mol/L Fe3+ at pH = 4-12. The different mechanisms of the three metal ions were identified by zeta potential, solution chemistry, and XPS analysis. Na+ only changed the zeta potential value of the calcite surface, which acted as a compressed electric double layer. However, the formation of metal hydroxide species or metal hydroxide surface precipitation due to the adsorption of Fe3+ and Mg2+ on the mineral surface resulted in the change of the dispersion behavior of calcite.

Effect of Fe3+ on electrowinning of copper by CE

To overcome the interference of Fe3+ in a leaching solution on copper electrowinning, a new copper electrowinning recovery process was developed by cyclone electrowinning (CE). The effects of Fe3+ on copper recovery, cathode copper morphology, and current efficiency under CE were studied. The addition amount of Fe3+ almost has no effect on the purity and electrowinning rate of cathode copper but affects the current efficiency of CE. The current efficiency decreases with the increase in Fe3+ concentration The current efficiency of first stage decreased from 99.6 % to 38.23 %. The current efficiency of second stage slightly decreased from 94.33 % to 77.94 %. The current efficiency of third stage decreased from 72.61 % to 27.2 %. The grain size of cathode copper with a high Fe3+ concentration increases, and the overall quality decreases. Therefore, the concentration of Fe3+ in the electrolyte should be properly controlled to efficiently obtain the copper cathode with good morphology before the CE of copper.

Synthetic Sulfide Concentrate Dissolution Kinetics in HNO3 Media.

The nature of tennantite (Cu12As4S13), chalcopyrite (CuFeS2) and sphalerite (ZnS) particles' mixture dissolution in nitric acid (HNO3) media was investigated in this study. The effects of temperature (323-368 K), HNO3 (1-8 mol/L) and Fe3+ (0.009-0.036 mol/L) concentrations, reaction time (0-60 min) and pyrite (FeS2) additive (0.5/1-2/1; FeS2/sulf.conc.) on the conversion of the minerals were evaluated. It has been experimentally shown that the dissolution of the mixture under optimal conditions (&gt;353 K; 6 mol/L HNO3; FeS2/synt. conc = 1/1) allows Cu12As4S13, CuFeS2 and ZnS conversion to exceed 90%. The shrinking core model (SCM) was applied for describing the kinetics of the conversion processes. The values of Ea were calculated as 28.8, 33.7 and 53.7 kJ/mol, respectively, for Cu12As4S13, CuFeS2 and ZnS. Orders of the reactions with respect to each reactant were calculated and the kinetic equations were derived to describe the dissolution rate of the minerals. It was found that the interaction between HNO3 solution and Cu12As4S13, CuFeS2 and ZnS under the conditions investigated in this are of a diffusion-controlled nature. Additionally, the roles of Fe(III) in the initial solution and FeS2 in the initial pulp as catalysts were studied. The results indicated that the increase in Fe3+ concentration significantly accelerates the dissolution of the mixture, while the addition of FeS2 forms a galvanic coupling between FeS2, and Cu12As4S13 and CuFeS2, which also accelerates the reaction rate. The results of the study are considered useful in developing a hydrometallurgical process for polymetallic sulfide raw materials treatment.

Relationship between the Texture and Composition of Titanomagnetite in Hannuoba Alkaline Basalt: A New Geospeedometer

The nucleation and growth of crystals in igneous rocks is usually thought to occur under thermodynamic equilibrium conditions. However, recent studies on igneous textures and mineral compositions have shown that these processes probably occur under thermodynamic disequilibrium conditions. Titanomagnetite with variable crystal sizes can be observed in Hannuoba alkaline basalt, indicating disequilibrium crystallization processes (different cooling rates). The ratio of the maximum particle size to the area abundance of titanomagnetite, as determined by an analysis of previous studies on the texture of minerals, was negatively correlated with the apparent cooling rate. We analyzed the chemical composition and crystal size distribution of titanomagnetite in ten Hannuoba alkaline basalt samples to determine the connection between the apparent cooling rate and titanomagnetite composition. In Hannuoba samples, the cooling rate was found to affect cationic substitution in the titanomagnetite solid solution, and an increase in cooling rate led to a decrease in Ti4+ and an increase in Fe3+. The partition coefficient of Ti between titanomagnetite and the melt (DTi) is negatively correlated with the apparent cooling rate. These findings are consistent with those in experimental petrology and help us propose a better, more general geospeedometer. The cooling rate also impacted Mg2+ and Al3+, but they were more impacted by the melt composition and crystallinity of the coexisting melt. Therefore, a new geospeedometer was calibrated by considering the titanomagnetite composition, melt composition and the content of the clinopyroxene.The cooling rates of the Hannuoba basalt samples measured using the new geospeedometer calibrated in this study range from 0.7 to 7.0 (±0.5) °C/min. It cannot accurately predict the cooling rate from titanomagnetite in intermediate rock, felsic rock or Fe-rich basaltic melts. The new titanomagnetite geospeedometer can better measure the cooling rate of alkaline basalt and may help identify the effects of kinetically controlled crystallization on isotope fractionation, evaluate mineral thermobarometers and better recognize thermal remanence magnetization and ancient magnetic fields.

The key role of crystal boron in enhanced degradation of refractory contaminants using heterogeneous Fe3+/SPC system

An origin Fenton-like system was discussed for the abatement of refractory contaminants. Sodium percarbonate (SPC) was utilized as the source of H2O2 and crystal boron (C-boron) was applied to enhance the activation of H2O2. Under the conditions of 0.50 mM Fe3+, 0.34 mM SPC, and heterogeneous catalysis using 100 mg L−1 C-boron, four target pollutants, at the initial concentrations of 20 μM, could be efficiently degraded by the Fenton-like system, with a degradation rate within 20 min up to 81.1% (aspirin, ASA), 92.8% (nitrobenzene, NB), 94.7% (flunixin meglumine, FMME), and 94.3% (benzoic acid, BA) respectively and total organic carbon removal up to 25.0%. The increase of Fe2+ concentration indicated that the conversion of Fe2+/Fe3+ was remarkably promoted by C-boron. Degradation reactions at acidic pH were comparatively fast, with pH-dependent kobs of 9.9 × 10−2 min−1 (ASA), 1.5 × 10−1 min−1 (NB), 1.7 × 10−1 min−1 (FMME), and 1.9 × 10−1 min−1 (BA), whereas those at neutral and alkaline pH were slower. Furthermore, reactive oxygen species including ·OH, 1O2, and O2·− were identified by in-situ electron paramagnetic resonance tests. The contribution ratios of ·OH turned out to be about 71.3–86.7% for the decomposition of four contaminants. The elimination of natural organic matter and the performance of material recycling highlighted the potential for its application in water treatment. The inhibition rate of Chlorella pyrenoidosa reached 211.9% in the C-boron/Fe3+/SPC system. The relatively high algae toxicity limited its application scope, which requires additional research to resolve.

S-3′-hydroxy-7′, 2′, 4′-trimethoxyisoxane, a novel ferroptosis inducer, promotes NSCLC cell death through inhibiting Nrf2/HO-1 signaling pathway

Background: Ferroptosis is a newly discovered and promising non-apoptotic programmed cell death (PCD), and inducing ferroptosis in cancer cells could open up a novel avenue for drug screening and cancer therapy. S-3′-hydroxy-7′, 2′, 4′-trimethoxyisoxane (ShtIX), a new isoflavane compound, has been reported to possess cytotoxicity in non-small cell lung cancer (NSCLC). The aim of this research is to explore the ShtIX-induced cell death form and its underlying molecular mechanism in NSCLC cells. Methods: Cell proliferation, cell cycle arrest, and cell death tests were used to assess the ability of ShtIX to kill NSCLC cells. Iron metabolism, Fe2+ content, reactive oxygen species (ROS) production, lipid peroxide (MDA) level, glutathione (GSH) level, and glutathione peroxidase 4 (GPX4) level were used to determine ferroptosis caused by ShtIX. We employed western blot, quantitative real-time PCR, and Nrf2 interference in NSCLC cells to investigate the roles of Nrf2/HO-1 in ShtIX-induced ferroptosis. In a xenograft nude mouse model, the anticancer efficacy of ShtIX and the function of ferroptosis were studied. Results: Our research shows that ShtIX can selectively kill NSCLC cells while sparing normal cells and that ShtIX-induced cell death can be efficiently reversed by the ferroptosis inhibitors and the iron chelator, but not by other cell death inhibitors. After cells were treated with ShtIX, there was an increase in Fe2+ content and lipid peroxidation accumulation, as well as a drop in GSH and GPX4 levels, all of which are indicators of ferroptosis. ShtIX also reduced the expression of Nrf2 and HO-1, and genetic Nrf2 silencing in NSCLC enhanced the effect of ShtIX-induced ferroptosis. Additionally, ShtIX retards tumor growth and induced ferroptosis through Nrf2/HO-1 signal pathway in the A549 xenograft model, whereas Fer-1 lessens the anticancer effect. Conclusion: This work provided the evidence that ShtIX caused ferroptosis in NSCLC cells, and inhibiting the Nrf2/HO-1 pathway can considerably exacerbate the effect of ShtIX-induced ferroptosis. The study establishes ShtIX as a promising natural ferroptosis inducer for the treatment of NSCLC.

Influence of Fe2+/Fetot on the viscosity of melts from the Colli Albani Volcanic District (Italy) – foidite to phonolite

Viscosity of a melt strongly depends on melt composition and the ratio of network modifiers to network formers. In silicate melts, Fe exists as Fe2+ and Fe3+, both affecting the viscosity in different manners: Fe2+ acts as a network modifier and lowers the viscosity whereas Fe3+ behaves as a network former and increases the viscosity. The Fe speciation strongly depends on the oxygen fugacity fO2.In this study, the viscosities of Fe-rich synthetic tephri-phonolitic, foiditic and tephritic melts from the Colli Albani Volcanic District (Italy) are investigated as a function of Fe2+/Fetot in the glass transition range. Base glasses made in air at 1600 °C at log10fO2 = −0.68 are re-equilibrated at log10fO2 = −4 and − 7 in a gas mixing furnace at 1250 °C. Melts made in air and at log10fO2 = −4 have nearly identical Fe2+/Fetot due to the different experimental temperatures. At 700 °C, the viscosity of these melts drops by ~2, ~1.5 and ~ 0.4 log10 Pa s with increasing Fe2+/Fetot from ~0.45, ~0.39 and ~ 0.44 to ~0.76 for the tephri-phonolite, the foidite and the tephrite, respectively. These melts have H2O concentrations up to 0.03 wt%. It is shown that the addition of ~0.23 wt% H2O reduces the viscosity by the same amount as the increase in Fe2+/Fetot.In addition, the viscosities of a phonolite from Mt. Vesuvius are studied over a range of Fe2+/Fetot values (~0.41 to 0.87). In contrast to the other melts of this study, viscosity appears to increase with increasing Fe2+/Fetot. However, this change in viscosity results from a depletion of ~14 mol% in network modifying alkali and alkaline earths elements and a loss of approx. 50 atom% Fe both affecting the viscosity of this melt more effectively than the increase in Fe2+/Fetot.