High Concentrations Of Iron Ions Research Articles

High Concentration of Iron Ions Contributes to Ferroptosis-Mediated Testis Injury.

In order to explore the effect of excessive iron supplementation on ferroptosis in mouse testes, Kunming mice received injections of varying concentrations of iron. The organ weight, sperm density, and malformation rate were measured. Observations of pathological and ultrastructural alterations in spermatogenic tubules were conducted using haematoxylin eosin (HE) staining and transmission electron microscopy(TEM). Transcript levels of related genes and serum biochemical indicators were measured in mouse testicular tissue. The results showed that higher iron concentration inhibited the growth of mice; reduced the organ coefficients of the testis, heart, and liver; and increased the rate of sperm malformation and mortality. Supplementation with high levels of iron ions can adversely affect the male reproductive system by reducing sperm count, damaging the structure of the seminiferous tubules and causing sperm cell abnormalities. In addition, the iron levels also affected the immune response and blood coagulation ability by affecting the red blood cells, white blood cells and platelets. The results showed that iron ions can affect mouse testicular tissue and induce ferroptosis by altering the expression of ferroptosis-related genes. However, the degree of effect was different for the different concentrations of iron ions. The study also revealed the potential role of deferoxamine in inhibiting the occurrence of ferroptosis. Nevertheless, the damage caused to the testis by deferoxamine supplementation suggests the need for further research in this direction. This study provides reference for reproductive toxicity induced by environmental iron exposure and clarifies the mechanism of reproductive toxicity caused by iron overload and the important role of iron in the male reproductive system.

A Green Cyclic Leaching Process for Low-Grade Pyrolusite via a Recyclable Fe(II) Reductant

The low-cost Fe(II) reductants used in the leaching of pyrolusite usually cause high concentrations of iron ions in the leaching solution, which are difficult to treat and recover. Herein, a green cyclic leaching process for pyrolusite with recycling and reusing of Fe(II) reductants was developed. Sodium sulfide was introduced to reduce and precipitate iron ions in the leaching solution. Ep-H diagrams show that Fe3+ can be reduced to Fe2+ by S2− and form a precipitate with the high efficiency of 93.09%. Since the main component of the precipitate was ferrous disulfide with reducibility, it was used as a reducing agent for low-grade manganese oxide ores. A total of 97.96% of the manganese was highly reductively leached by the obtained precipitate of 0.28 g·g−1 ore. Furthermore, the leaching efficiency was almost unchanged after five iterations of cyclic experiments. The cyclic leaching process enables the efficient leaching of manganese and the recycling of iron, which provides a green and economic method for the efficient utilization of low-grade pyrolusite resources.

Recovery of Rare Earth Elements from the Leaching Solutions of Spent NdFeB Permanent Magnets by Selective Precipitation of Rare Earth Oxalates

After mechanical pre-treatment, the typical hydrometallurgical route of NdFeB magnet recycling starts with leaching in acidic solutions. However, due to the high concentration of iron ions in the leaching solution, the selective recovery of rare earths from the solution is challenging. In our work, the selective precipitation of rare earth oxalates as a potential separation method was proposed. The precipitation of neodymium oxalate was first tested on model solutions, which was then followed by experimental tests carried out on real solutions after the leaching of NdFeB magnets. The recovery of rare earths in the form of oxalates was investigated with the use of different amounts of oxalic acid in relation to its stoichiometric amount. The most efficient separation of rare earths was observed in the case where sulfuric acid was used for leaching. The use of oxalic acid in stoichiometric amounts resulted in the precipitation of about 93% of all rare earths present in the solution, whereas the concentration of Fe and other elements (Ni, Co, and B) practically did not change. An increase in oxalic acid of 20% and 40% more than the stoichiometric amount (100%) led to the increase in the precipitation efficiency of rare earths to 96.7% and 98.1%, respectively. However, the use of oxalic acid in a 1.4 ratio caused a 7% decrease in Fe concentration, which suggests Fe co-precipitation. In order to investigate a possibility of further increasing the separation of rare earths from iron, an additional method was tested, in which iron was first oxidized from Fe2+ to Fe3+ before the precipitation of rare earth oxalates.

Fluorapatite nanorod arrays with enamel-like bundle structure regulated by iron ions.

Pigmented rodent tooth enamel is mainly composed of parallel hydroxyapatite nanorods and a small amount of organic matrix. These hydroxyapatite nanorods tend to be carbonated and contain traces of iron, fluorine, and magnesium. The pigmented rodent tooth enamel which contains trace iron is stronger and more resistant to acid corrosion than unpigmented rodent enamel, which could provide inspiration for the preparation and synthesis of high performance and corrosion resistant artificial materials. However, the regulatory role and mechanical enhancement of iron ions in enamel growth are unclear. Here, we synthesized enamel-like fluorapatite nanorod arrays in vitro using a mineralization technique at room-temperature. To investigate the regulatory effect of iron ions on the fluorapatite nanorod arrays (FAP-Fe), the phosphate solution is slowly transfused dropwise in the calcium ion solution, and different concentrations of iron ions are added to the calcium ion solution in advance. We demonstrated that fluorapatite nanorod arrays (FAP) can be epitaxially grown from amorphous calcium phosphate nanoparticles and iron ions can improve the microstructure of FAP nanorod arrays and obtain the same enamel bundle structure as the natural enamel. Moreover, high concentration of iron ions can inhibit the crystallization of fluorapatite. The FAP-Fe nanorod arrays controlled by 0.02 mM Fe3+ have good mechanical properties. Their hardness is 1.34 ± 0.02 GPa and Young's modulus is 65.3 ± 0.4 GPa, respectively. This work is helpful to understand the role of trace elements in natural enamel in the regulation of enamel formation and to provide a theoretical foundation for the preparation of high strength artificial composites, which can play a greater role in the fields of biological alternative materials, anti-oil coating, oil/water separation, anti-bioadhesion and so on.

Iron Oxides Nanoparticles as Components of Ferroptosis-Inducing Systems: Screening of Potential Candidates

This study presents an analysis of a set of iron oxides nanoparticles (NPs) (γ-Fe2O3, α-FeOOH, δ-FeOOH, 5Fe2O3·9H2O, and Fe3O4) as potential candidates for ferroptosis therapy in terms of a phase state, magnetic characteristics, and the release of Fe2+/Fe3+ as ROS mediators. Due to the values of saturation magnetization for Fe3O4 (31.6 emu/g) and γ-Fe2O3 (33.8 emu/g), as well as the surface area of these particles (130 and 123 m2/g), it is possible to consider them as promising magnetically controlled carriers that can function with various ligands. The evaluation of the release of Fe2+/Fe3+ ions as catalysts for the Fenton reaction showed that the concentration of the released ions increases within first 3 h after suspension and decreases within 24 h, which probably indicates desorption and adsorption of ions from/onto the surface of nanoparticles regardless their nature. The concentration of ions released by all nanoparticles, except α-FeOOH-Fe2+, reached 9.1 mg/L for Fe3+ to 1.7 mg/L for Fe2+, which makes them preferable for controlling the catalysis of the Fenton reaction. In contrast, a high concentration of iron ions to 90 mg/L for Fe3+ and 316 mg/L for Fe2+ released from compound α-FeOOH-Fe2+ allows us to utilize this oxide as an aid therapy agent. Results obtained on iron oxide nanoparticles will provide data for the most prospective candidates that are used in ferroptosis-inducing systems.

Removal of artificial iron ions using activated carbon from sago pith waste

In the present day, the industry is growing rapidly. Every process in the industries brings out pollution. Heavy metals, especially iron ions have contaminated water resources due to industrial activity. The high concentration of iron ions is dangerous for human life. To solve this issue an activated carbon from sago pith waste was developed to remove iron ions from industrial wastewater represented by artificial iron solution. The objective of this research is to measure the adsorption capacity of sago pith waste activated carbon (SPWAC) for treating artificial iron solution. The adsorbent was carbonized at 300 °C and 80 min. Further, it was activated by citric acid 0.1 M. The treated iron solution was analyzed by condutometer to examine the iron content. Subsequently, the functional groups of SPWAC were tested via Fourier Transform Infra-Red (FTIR). The result indicates that the SPWAC can reject iron ions of more than 80 % with an iron ions concentration of 1.81 mg/L at 60 min and 300 rpm. While, FTIR analysis show alkenes, carbonyl, and hydroxyl groups are present in SPWAC. The iron ions concentration in treated water is below the allowable threshold (0.3 mg/L) based on World Health Organization (WHO) guidelines for drinking water. Therefore, the SPWAC is promising technology to be applied for treating industrial wastewater.

Utilization of Spent Sorbent in the Production of Ceramic Bricks

The composition and technology for the production of semi-dry ceramic bricks using a nanostructured complex sorbent based on bentonite clay of the 11th horizon of the Tagan deposit of the Republic of Kazakhstan and basalt fiber (gabbro-diabase) of the Karauzek deposit of East Kazakhstan have been developed. The characteristics, chemical composition, and structure of the spent sorbent are given based on electron microscopic and X-ray phase analyses. A number of physical and mechanical parameters have been studied to evaluate the spent sorbent as a raw material for the production of ceramic products. The microstructures of fired ceramic samples with loam and spent sorbent have been studied, and the features of their structure have been revealed. The environmental safety of waste sorbents utilization by extraction in acidic, alkaline, and neutral media with the determination of the content of chromium, zinc, and iron ions has been studied. Experimentally obtained data indicate an insignificant concentration of chromium and zinc ions, not exceeding 3.5 µg/L. Relatively high concentrations of iron ions in ceramic bricks are associated with their high content in the feedstock and in the spent sorbent. It has been established that the introduction of the spent sorbent in the amount of 25% of the total mass increases the strength of the final product from 10.8 to 15.8 MPa, which corresponds to the M125 ceramic brick grade.

Extrusion-based 3D printed biodegradable porous iron

Extrusion-based 3D printing followed by debinding and sintering is a powerful approach that allows for the fabrication of porous scaffolds from materials (or material combinations) that are otherwise very challenging to process using other additive manufacturing techniques. Iron is one of the materials that have been recently shown to be amenable to processing using this approach. Indeed, a fully interconnected porous design has the potential of resolving the fundamental issue regarding bulk iron, namely a very low rate of biodegradation. However, no extensive evaluation of the biodegradation behavior and properties of porous iron scaffolds made by extrusion-based 3D printing has been reported. Therefore, the in vitro biodegradation behavior, electrochemical response, evolution of mechanical properties along with biodegradation, and responses of an osteoblastic cell line to the 3D printed iron scaffolds were studied. An ink formulation, as well as matching 3D printing, debinding and sintering conditions, was developed to create iron scaffolds with a porosity of 67%, a pore interconnectivity of 96%, and a strut density of 89% after sintering. X-ray diffracometry confirmed the presence of the α-iron phase in the scaffolds without any residuals from the rest of the ink. Owing to the presence of geometrically designed macropores and random micropores in the struts, the in vitro corrosion rate of the scaffolds was much improved as compared to the bulk counterpart, with 7% mass loss after 28 days. The mechanical properties of the scaffolds remained in the range of those of trabecular bone despite 28 days of in vitro biodegradation. The direct culture of MC3T3-E1 preosteoblasts on the scaffolds led to a substantial reduction in living cell count, caused by a high concentration of iron ions, as revealed by the indirect assays. On the other hand, the ability of the cells to spread and form filopodia indicated the cytocompatibility of the corrosion products. Taken together, this study shows the great potential of extrusion-based 3D printed porous iron to be further developed as a biodegradable bone substituting biomaterial.

Superparamagnetic Iron Oxide Nanoparticles Induce Ferroptosis of Human Ovarian Cancer Stem Cells by Weakening Cellular Autophagy.

Human ovarian cancer stem cells (HuOCSCs) are the main source of ovarian cancer recurrence, metastasis, and drug resistance. Superparamagnetic iron oxide nanoparticles (SPIONs) are well-known nucleic acid or drug carriers owing to their controllable properties, superior stability, and easy modification. However, whether SPIONs can inhibit the activity of HuOCSCs by inducing ferroptosis remains unclear. In the present study, we isolated CD44+ /CD133+ HuOCSCs from tumours of four patients with clear cell ovarian cancer and added 0.2 mM SPIONs for mixed culture. Transmission electron microscopy showed that SPION-treated HuOCSCs contained multiple high-density electron clouds. Prussian blue staining showed high concentrations of iron ions in the cells. In vitro , SPIONs treatment of HuOCSCs inhibited cell proliferation, migration, and soft agar clone formation, weakened their resistance to multiple chemotherapeutics, and induced cell death. In vivo , SPIONs pretreatment of HuOCSCs significantly reduced their tumour-forming ability and induced angiogenesis in nude mice. Further, SPIONs induced the accumulation of reactive oxygen species in HuOCSCs and induced oxidative stress. qPCR analysis indicated that SPIONs-treated HuOCSCs had reduced expression of tumour stem cell markers (CD117, NANOG, CD133, and SOX2), cell proliferation factors (KI67, CCND), autophagy-related factors (ATG3, ATG5, MAP1ALC3a, MAP1ALC3b, and MAP1ALC3c), and certain negative regulators of ferroptosis, while the mRNA expression levels of cell death-related proteins (BAK1 and BID), and certain positive regulators of ferroptosis were significantly increased. Overall, our findings suggest that SPIONs induce oxidative stress and decrease autophagy activity in ovarian cancer stem cells, activate ferroptosis, and inhibit their proliferation, invasion, drug resistance, and tumorigenic ability.

Formation mechanism of iron scale in membrane capacitive deionization (MCDI) system

In this study, we investigated the scaling behaviors of Fe in the membrane capacitive deionization (MCDI) systems through batch experiments. By analyzing the migration and transformation of Fe in the MCDI system, it was found that Fe scale was deposited on the ion exchange membrane rather than on the electrode. The characterizations of Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) showed that the FeOOH formed in the solution deposited on the anion exchange membrane, while the iron scale on the cation exchange membrane was mainly Fe2O3. In the presence of 1 mg/L iron ions, the amount of iron ions adsorbed by the MCDI system was about 25% less than that by the capacitive deionization (CDI). However, at 10 mg/L iron ions, the amount of iron ions absorbed by the MCDI system was almost twice that by the CDI system. This was because that the high concentration of iron ions produced a large number of yellow flocs which were adsorbed by the cation exchange membrane. Ion exchange membrane increased the adsorption capacity of the CDI system, but it did not alleviate the scaling caused by Fe.

Rapid determination of iron concentration in wastewater using color band formation

High concentrations of iron ions in water bodies cause odour and discolouration due to their precipitation. The total iron ion concentration is generally analysed on-site by forming coloured compounds and measuring colour intensity with spectrophotometric or visual analysis. In this work, we developed a detection tube as an alternative simple analytical method, where the total iron ion concentration is measured not by colour but by an objective parameter called the colour band length (CBL). Tiron was selected as the colouring agent since it oxidises divalent iron ions into a trivalent state and reacts with trivalent iron ions to form a 3:1 anion complex in alkaline media, giving a red colour. The coloured solution penetrates the detection tube by capillarity, and the colour band is formed by the entrapment of the hydrophobic ion pair of iron-tiron complex and quaternary ammonium ions of the adsorbent filled in the tube. The CBL was found to correlate well with the total iron ion concentration quantitatively under the optimized measurement condition, and 5 to 40 mg-FeL−1 solutions could be measured with good objectivity and precision.

Ecological condition of the small north river after emergency release of oil products

The features of the chemical compositions of the surface water, bottom sediments, and zoobenthos communities of the small forest water way after an oil pipeline accident were investigated herein. Nine months after the oil spillage, an increased content of oil hydrocarbons (2.8 MAC) remained in the surface water downstream the place of the emergency release of oil-containing liquid. The detected high concentrations of iron ions (1.1–4.6 MAC) and copper (1.2–2.6 MAC) and the decomposition-resistant organic compounds (1.2–3.3 MAC) were typical for the background area, which certified their almost natural origin. The oil hydrocarbon content in the bottom sediments below the emergency release of oil in the water way exceeded the backgrounds one in 7–214 times. Zoobenthos is presented by 18 groups in the water ways of the region under consideration, out of which, 14 groups were detected in the contamination area. The modification of the zoobenthos structure and the reduction of its quantitative indicators of development were observed in the direction from the Vozeyshor creek. The dominance of entomostracans and oligochaete was detected in the bottom communities of the oil-contaminated areas.

Purification of subsoil water from iron compounds in Zhytomyr region

The most valuable type of water resources are fresh water supply. These resources are, in general, much cleaner than surface water. Its runoff is stable and its quality (excl. infiltration waters) is almost independent from the weather (seasonal) changes. Almost all Ukrainian subsoil water-bearing horizons have a high concentration of iron ions, ranging from 0.5 mg/l to 50 mg/l and more. By analyzing known methods of water neutralization, we can conclude that at low concentrations of activated earth ions in the initial water proved to be quite well established. The most common method of water deironing is the process of filtering, using natural or artificial granular loads, with up to 10 m/h water filtration rate.

Extraction of Vanadium from Chloride Solutions Using Di (2-Ethylhexyl) Phosphate

Extraction of vanadium has been developed to extract vanadium from hydrochloric solutions with high concentration of iron ions. The effects of extraction conditions such as pH values, extraction time and extraction temperature on the distribution ratio of vanadium were investigated. The results showed that the distribution ratio of vanadium increased with the higher pH, the lower temperature and the longer equilibrium time. The distribution ratio reached 25 and the extraction ratio reached 96.2% by single stage extraction. When the organic phase was stripped with 2 mol/L hydrochloric acid at the phase ratio (O/A) 10:1, the vanadium stripping ratio of 98.3% could be achieved.

Iron Binding at Specific Sites within the Octameric HbpS Protects Streptomycetes from Iron-Mediated Oxidative Stress

The soil bacterium Streptomyces reticuli secretes the octameric protein HbpS that acts as a sensory component of the redox-signalling pathway HbpS-SenS-SenR. This system modulates a genetic response on iron- and haem-mediated oxidative stress. Moreover, HbpS alone provides this bacterium with a defence mechanism to the presence of high concentrations of iron ions and haem. While the protection against haem has been related to its haem-binding and haem-degrading activity, the interaction with iron has not been studied in detail. In this work, we biochemically analyzed the iron-binding activity of a set of generated HbpS mutant proteins and present evidence showing the involvement of one internal and two exposed D/EXXE motifs in binding of high quantities of ferrous iron, with the internal E78XXE81 displaying the tightest binding. We additionally show that HbpS is able to oxidize ferrous to ferric iron ions. Based on the crystal structure of both the wild-type and the mutant HbpS-D78XXD81, we conclude that the local arrangement of the side chains from the glutamates in E78XXE81 within the octameric assembly is a pre-requisite for interaction with iron. The data obtained led us to propose that the exposed and the internal motif build a highly specific route that is involved in the transport of high quantities of iron ions into the core of the HbpS octamer. Furthermore, physiological studies using Streptomyces transformants secreting either wild-type or HbpS mutant proteins and different redox-cycling compounds led us to conclude that the iron-sequestering activity of HbpS protects these soil bacteria from the hazardous side effects of peroxide- and iron-based oxidative stress.

The heme-binding protein HbpS regulates the activity of the Streptomyces reticuli iron-sensing histidine kinase SenS in a redox-dependent manner

The SenS/SenR system of Streptomyces reticuli regulates the expression of the redox regulator FurS, the catalase-peroxidase CpeB and the heme-binding protein HbpS. SenS/SenR is also proposed to participate in sensing redox changes, mediated by HbpS. Here, we show in vitro that heme-free HbpS represses the autokinase activity of SenS; whereas hemin-treated HbpS considerably enhances SenS autophosphorylation under redox conditions using either H(2)O(2) or DTT. The presence of iron ions alone or in combination with H(2)O(2) or DTT also leads to significantly increased phosphorylation levels of SenS. Further comparative physiological studies using the S. reticuli WT, a S. reticuli hbpS mutant and a S. reticuli senS-senR mutant corroborates the importance of HbpS and the SenS/SenR system for resistance against high concentrations of iron ions and hemin in vivo. Hence SenS/SenR and HbpS act in concert as a novel three-component system which detects redox stress, mediated by iron ions and heme.

Thermomagnetic effects in a two-dimensional system containing mixed valence impurities

The results of calculation of the transverse Nernst-Ettinsgausen (NE) effect in a two-dimensional system containing mixed-valence impurities are presented. It is shown that the NE coefficient changes sign at low temperatures and when the iron content is fairly high. The unusual dependence of the NE effect on iron content in the two-dimensional (HgSe : Fe) system at low temperatures is caused by electron scattering on the aggregate of charged donors Fe(3+). At low temperatures and high concentration of iron ions the system of charged donors is the strongly correlated Coulomb liquid.