Change In Oxidation State Research Articles

Dynamic recycling behavior of Cu/Zn-based electrodes in electrochemical CO2 reduction

Recycling and electrode stability are crucial in electrochemical CO2 reduction (EC CO2R), especially due to changes in electrode behavior under negative reduction potentials. This study investigates the EC CO2R products over multiple recycling steps using Cu, Zn, and CuZn metals, along with their oxides. Our findings reveal significant variations in reduction products and their Faradaic efficiencies (FEs), dependent on the electrode type. Initially, Cu and its oxide, as well as the CuZn alloy and its oxide, displayed varying FEs, but their performance normalized in later recycles. Conversely, Zn and its oxide showed consistent differences throughout the recycles. Depth-profiling X-ray photoelectron spectroscopy was used to analyze the electrodes’ composition and oxidation states post-reaction. The analyses highlighted substantial changes in oxidation states and the distribution of metallic and oxidized states, particularly in the Zn/Cu ratio. These insights are essential for developing stable electrodes for energy and environmental applications.

Modification of the electronic and optical properties of YVO4:Eu induced by different charge states of the Eu ion

By employing first-principles calculations within the frame of density functional theory, we investigated the modifications of the electronic and optical properties of isolated Eu impurities within YVO4:Eu3+ compound in the presence of additional electron charges. This scenario arises when YVO4:Eu3+ is exposed to gamma radiation that ejects electrons from certain ions and makes them available for capture by others. Our findings reveal that a significant portion of the additional charge is captured by the Eu3+ ion (0.32 e), but this portion is insufficient to confirm a change in the Eu oxidation state from 3+ to 2+. Nevertheless, this capture significantly modifies the Eu electronic configuration, elevating the energy of its occupied 4f-states and bringing them closer to the conduction band bottom. This fact causes the optical absorption of Eu to be generated by 4f → 5d electron transitions, instead of 4f → 4f as in the case of the non-irradiated compound. The presented results qualitatively explain drastic changes in the Eu emission spectrum induced by gamma irradiation of the YVO4:Eu3+, perceived experimentally.

Statistical estimation of the early to middle Ediacaran ocean redox architecture in the Yangtze block of South China

Early to middle Ediacaran organic-rich black shales host several famous fossil biotas and provide key evidence for understanding the coevolution of multicellular organisms and palaeoceanic environment. The water column redox states play critical roles in organic-rich shale deposition. Amongst multiple geochemical redox indexes, iron-speciation chemistry (FeHR/FeT, Fepy/FeHR) in shales constitutes a reliable proxy to reconstruct the first-order redox framework of the ocean basin. However, iron-speciation is a local marine redox proxy, and only compiled data collected from multiple different sedimentary facies record statistically significant changes of oxidation states within a depositional basin. Here we compiled the spatiotemporal distribution of iron-speciation data in early to middle Ediacaran black shales of the Yangtze block in South China. New high-resolution analysis on two outcrops and one drill-core reflects overall ferruginous condition and dominant euxinic condition locally interrupted by oxic states, respectively, generally indicating pervasive anoxic depositional environment for the Member II shales of the Ediacaran Doushantuo Formation in the Lower Yangtze block. Compilation of fourteen Ediacaran sections from shallow-, slope- and deep-water facies demonstrates frequent spatiotemporal oscillation of the redox conditions throughout the Yangtze block. Widespread ferruginous states, accompanied with euxinic zones mainly focusing in lower slope facies, are detected during the early Ediacaran period, in contrast with more widespread euxinic settings in the middle Ediacaran period. Statistical data including new high-resolution results from the Lower Yangtze block show generally low enrichment for redox sensitive elements (RSEs, e.g., Mo, V and U) in the Member II shales probably due to their contemporary low seawater concentrations. An increase of RSEs concentrations occurs in the Member IV shales, which probably reflects more oxidized Earth surface environment during middle Ediacaran period. The increasing Earth oxygenation documents the occurrence of widespread euxinic states during deposition of the Member IV shales. Compilation of spatial distribution of TOC contents in black shales demonstrates their apparent relevance to spatial distribution of the euxinic rather than ferruginous states, which is likely due to the favorable role of sulfurization process on burial and preservation of organic matters. The euxinic states may also facilitate the exceptional preservation of the soft-bodied Ediacaran fossils.

In-Depth Analysis of the Species and Transformations during Sol Gel-Assisted V2PC Synthesis.

The sol-gel reaction mechanism of 211 MAX phases has proven to be very complex when identifying the intermediate species, chemical processes, and conversions that occur from a mixture of metal salts and gelling agent into a crystalline ternary carbide. With mostly qualitative results in the literature (Cr2GaC, Cr2GeC, and V2GeC), additional analytical techniques, including thermal analysis, powder diffraction, total scattering, and various spectroscopic methods, are necessary to unravel the identity of the chemical compounds and transformations during the reaction. Here, we demonstrate the combination of these techniques to understand the details of the sol-gel synthesis of MAX phase V2PC. The metal phosphate complexes, as well as amorphous/nanocrystalline vanadium phosphate species (V in different oxidation states), are identified at all stages of the reaction and a full schematic of the reaction process is suggested. The early amorphous vanadium species undergo multiple changes of oxidation states while organic species decompose releasing a variety of small molecule gases. Amorphous oxides, analogous to [NH4][VO2][HPO4], V2PO4O, and VO2P2O7 are identified in the dried gel obtained during the early stages of the heating process (300 and 600 °C), respectively. They are carbothermally reduced starting at 900 °C and subsequently react to crystalline V2PC with the excess carbon in the reaction mixture. Through CHN analysis, we obtain an estimate of left-over amorphous carbon in the product which will guide future efforts of minimizing the amount of carbon in sol gel-produced MAX phases which is important for subsequent property studies.

Thermodynamics of Proton-Coupled Electron Transfer at Tricopper μ-Oxo/Hydroxo/Aqua Complexes.

Multicopper oxidases (MCOs) utilize a tricopper active site to reduce dioxygen to water through 4H+ 4e- proton-coupled electron transfer (PCET). Understanding the thermodynamics of PCET at a tricopper cluster is essential for elucidating how MCOs harness the oxidative power of O2 while mitigating oxidative damage. In this study, we determined the O-H bond dissociation free energies (BDFEs) and pKa values of a series of tricopper hydroxo and tricopper aqua complexes as synthetic models of the tricopper site in MCOs. Tricopper intermediates on the path of alternating electron and proton transfer (ET-PT-ET-PT-ET) have modest BDFE(O-H) values in the range of 53.0-57.1 kcal/mol. In contrast, those not on the path of ET-PT-ET-PT-ET display much higher (78.1 kcal/mol) or lower (44.7 kcal/mol) BDFE(O-H) values. Additionally, the pKa of bridging OH and OH2 motifs increase by 8-16 pKa units per oxidation state. The same oxidation state changes have a lesser impact on the pKa of N-H motif in the secondary coordination sphere, with an increase of ca. 5 pKa units per oxidation state. The steeper pKa increase of the tricopper center promotes proton transfer from the secondary coordination sphere. Overall, our study shed light on the PCET pathway least prone to decomposition, elucidating why tricopper centers are an optimal choice for promoting efficient oxygen reduction reaction.

Neurotoxicity of Some Environmental Pollutants to Zebrafish

The aquatic environment encompasses a wide variety of pollutants, from plastics to drug residues, pesticides, food compounds, and other food by-products, and improper disposal of waste is the main cause of the accumulation of toxic substances in water. Monitoring, assessing, and attempting to control the effects of contaminants in the aquatic environment are necessary and essential to protect the environment and thus human and animal health, and the study of aquatic ecotoxicology has become topical. In this respect, zebrafish are used as model organisms to study the bioaccumulation, toxicity, and influence of environmental pollutants due to their structural, functional, and material advantages. There are many similarities between the metabolism and physiological structures of zebrafish and humans, and the nervous system structure, blood–brain barrier function, and social behavior of zebrafish are characteristics that make them an ideal animal model for studying neurotoxicity. The aim of the study was to highlight the neurotoxicity of nanoplastics, microplastics, fipronil, deltamethrin, and rotenone and to highlight the main behavioral, histological, and oxidative status changes produced in zebrafish exposed to them.

Time‐Resolved Oxidation State Changes Are Key to Elucidating the Bifunctionality of Perovskite Catalysts for Oxygen Evolution and Reduction

In a unified regenerative fuel cell (URFC) or reversible fuel cell, the oxygen bifunctional catalyst must switch reversibly between the oxygen reduction reaction (ORR), fuel cell mode, and the oxygen evolution reaction (OER), electrolyzer mode. However, it is often unclear what effect alternating between ORR and OER has on the electrochemical behavior and physiochemical properties of the catalyst. Herein, operando X‐ray absorption spectroscopy (XAS) is utilized to monitor the continuous and dynamic evolution of the Co, Mn, and Fe oxidation states of perovskite catalysts Ba0.5Sr0.5Co0.8Fe0.2O3‐δ (BSCF) and La0.4Sr0.6MnO3‐δ (LSM), while the potential is oscillated between reducing and oxidizing potentials with cyclic voltammetry. The results reveal the importance of investigating bifunctional catalysts by alternating between fuel cell and electrolyzer operation and highlight the limitations and challenges of bifunctional catalysts. It is shown that the requirements for ORR and OER performance are divergent and that the oxidative potentials of OER are detrimental to ORR activity. These findings are used to give guidelines for future bifunctional catalyst design. Additionally, it is demonstrated how sunlight can be used to reactivate the ORR activity of LSM after rigorous cycling.

First-principles study of the structures and redox mechanisms of Ni-rich lithium nickel manganese cobalt oxides

To reduce the cobalt (Co) content in lithium-ion batteries, Ni-rich (high-Ni) lithium nickel manganese cobalt oxides (NMC) are pursued as one of the next-generation cathode materials. However, there is still debate on the crystal and electronic structures of the baseline, LiNiO2. Density Functional Theory (DFT) calculations were performed to provide a theoretical understanding of Ni-rich NMC. First, it was found that the commonly used R3¯m structure for LiNiO2 is metallic, contrary to the experimentally reported mix-conducting behavior. Among the four different space groups, R3¯m, C2/m, P21/c, and P2/c, P2/c with charge disproportionation of Ni2+ and Ni4+ is the most energetically stable and semiconducting structure of LiNiO2. Therefore, the atomic structures of representative Ni-rich NMC were built by partially replacing Ni with Co or Mn in the P2/c LiNiO2 to form LixNiyMnzCo1-y-zO2. In the fully lithiated (x = 1.0) high Ni content NMC (y > 0.5), the oxidation state of all Mn ions becomes 4+, while Co ions still maintain 3+, and part of the Ni ions become 2+ to compensate for the charge. Upon delithiation, the local environment shows more variation of the charge states on the transition metal (TM) ions. The average oxidation on each TM follows a sequence of losing electrons that starts from Ni2+ to Ni3+, then oxidizing Ni3+ and Co3+, while Mn4+ remains electrochemically inactive till x = 0. A general relationship for the oxidation state change in each TM as a function of x and y is derived and shows agreement with both modeling and experimental data.

Exposure to Microplastics Made of Plasmix-Based Materials at Low Amounts Did Not Induce Adverse Effects on the Earthworm Eisenia foetida.

The implementation of recycling techniques represents a potential solution to the plastic pollution issue. To date, only a limited number of plastic polymers can be efficiently recycled. In the Italian plastic waste stream, the residual, non-homogeneous fraction is called 'Plasmix' and is intended for low-value uses. However, Plasmix can be used to create new materials through mechanical recycling, which need to be tested for their eco-safety. This study aimed to investigate the potential toxicity of two amounts (0.1% and 1% MPs in soil weight) of microplastics (MPs) made of naïve and additivated Plasmix-based materials (Px and APx, respectively) on the earthworm Eisenia foetida. Changes in oxidative status and oxidative damage, survival, gross growth rate and reproductive output were considered as endpoints. Although earthworms ingested both MP types, earthworms did not suffer an oxidative stress condition or growth and reproductive impairments. The results suggested that exposure to low amounts of both MPs can be considered as safe for earthworms. However, further studies testing a higher amount or longer exposure time on different model species are necessary to complete the environmental risk assessment of these new materials.

Neighboring Effects of Sulfur Oxidation State on Dynamic Covalent Bonds and Assemblies.

The impact of a varied sulfur oxidation state (sulfide, sulfoxide, and sulfone) on imine dynamic covalent chemistry is presented. The role of noncovalent interactions, including chalcogen bonds and CH hydrogen bonds, on aldehyde/imine structures and imine exchange reactions was elucidated through experimental and computational evidence. The change in the sulfur oxidation state and diamine linkage further allowed the regulation of imine macrocycles, providing a platform for controlling molecular assemblies.

Structural, DFT and redox activity investigation of 2D silver based MOF for energy storage devices

A new silver(I) 2D MOF (Ag-MOF) was synthesized from 3,4-pyridinedicarboxylic acid (PDCA) by sonication method and characterized by single crystal X-ray diffraction, elemental analysis and FTIR spectroscopy. The material was further utilized for DFT computation and electrochemical performance. Theoretical and practicalresults for Ag-MOF geometrical parameters were found to be in reasonable agreement. Small HOMO-LUMO energy distance of 0.47 eV confirmed that electron transfer was much feasible. Distribution of electron isodensities was elaborated by DFT and FMOs computation. Double redox peaks in CV voltammograms reflected the change in oxidation state. Multiple plateaus in GCD curves showed the pseudo-capacitive behavior. Ag-MOF exhibited 101 Cg−1 specific capacity (Qs), 123 Wh.kg−1 energy density and 12,960 W kg−1 power density at current density of 5 Ag−1. There was a small difference in Rct and Ri which revealed that Ag-MOF had great ability to store energy. Presence of semi-circular arc in the EIS spectrum directly dictates the supercapacitor behavior. The electrode showed 97.5 % cyclic stability after 5000 cycles.

Molecular mechanisms of resveratrol and its silver nanoparticle conjugate in addressing sepsis-induced lung injury

Sepsis is a life-threatening condition characterized by a systemic inflammatory response to infection. Despite extensive research on its pathophysiology, effective therapeutic approaches remain a challenge. This study investigated the potential of resveratrol (RV) and silver nanoparticle–enhanced resveratrol (AgNP-RV) as treatments for sepsis-induced lung injury using a rat model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). The study focused on evaluating changes in oxidative status (TAS, TOS, and OSI) and the expression of inflammatory and apoptotic markers (IL-1β, TNF-α, P2X7R, TLR4, Caspase-3, and Bcl-2) in lung tissue. Both RV and AgNP-RV demonstrated potential in mitigating oxidative stress, inflammation, and apoptosis, with AgNP-RV exhibiting greater efficacy than RV alone (p < 0.05). These findings were corroborated by histopathological analyses, which revealed reduced tissue damage in the RV- and AgNP-RV-treated groups. Our study highlights the therapeutic potential of RV and, particularly, AgNP-RV in combating sepsis-induced oxidative stress, inflammation, and apoptosis. It also underscores the promise of nanoparticle technology in enhancing therapeutic outcomes. However, further investigations are warranted to fully understand the mechanisms of action, especially concerning the role of the P2X7 receptor in the observed effects. Nonetheless, our research suggests that RV and AgNP-RV hold promise as novel strategies for sepsis management.

Potentially toxic elements distribution, petrography, and synchrotron characterization in polluted soils around industrial complex, Central Jordan

Industry is the main source of soil pollution in Jordan, where higher concentrations of potentially toxic elements were found in the soil around industrial estates. This study is dealing with an industrial pollution hot spot that is a steel factory in central Jordan that emits various ashes and gases. This area is moderately inhibited, and its soil is increasingly utilized in agricultural activities. High Fe, Cr, Mn, Pb, and V contents were recorded in the soil adjacent to the factory mainly concentrated on the prevailing wind direction. The studied sites bear heavy metalloids concentrations exceeding the permissible limit of WHO/EPA. These concentrations were found in topsoils and they decreased downward because of low mobility due of high soil alkalinity and lower pedogenesis. Moreover, the synchrotron-based XAFS technique was used to understand changes in oxidation states of Fe atom as well as in its structural parameters with depth. EXAFS analysis reveals association of Fe atoms mainly with oxygen (O), which indicates the anthropogenic Fe source. XANES data shows that Fe occurs in divalent (Fe2+) and trivalent (Fe3+) forms, which indicates that magnetite is dominating the topsoil. This Fe-phase is usually formed during oxygenated high thermal manufacturing processes. The topsoils SEM-EDS investigations confirmed the dominance of magnetite spheres, which coincides with the positive correlation between Fe and other elements as indicated from the statistical interpretation of the data.

Changes in Blue Color of Sapphire Compared with Oxidation State Changes

Blue sapphire has long been treated with heat to modify its blue color and attain greater value. However, the process of modifying the blue color in sapphire remains not well understood. The color-changing mechanism has traditionally been explained using the Intervalence Charge Transfer (IVCT) (Fe2+-Ti4+ and/or Fe2+-Fe3+) theory, wherein the blue color can be diminished by heat treatment in an oxidizing environment which alters Fe2+ (FeO) to Fe3+ (Fe2O3) and decreases the occurrence of the IVCT process. However, recently, the band gap theory has been proposed, suggesting that iron (Fe) in sapphire is always in the Fe3+ state, the blue color is caused by Fe3+-Ti4+ pair and the heat treatment does not affect Fe oxidation state. Therefore, in this study, eight magmatic sapphires from four localities were investigated for changes in blue color via color analysis, changes in spectra using XANES, and changes in chemical composition using PIXE both before and after heat treatment. The color analysis reveals a slight reduction in saturation (fading of blue) and a noticeable lightening after heat treatment, which corresponds with the high content of solid inclusions or trapiche samples. XANES data analysis using the LCF technique indicated insignificant changes in Fe oxidation state from 2+ to 3+ after heat treatment across all samples. However, when comparing the XANES data with color parameter L*a*b*, it is noted that the percentage of Fe oxidation state changes does not show a positive relationship with changes in blue based on color parameter b* (blue–yellow); rather, it shows a positive relationship with parameter L* (lightness). Microscopic observations also reveal the dissolution of clouds or minute particles around planes of ilmenite needles. It could be suggested that the changes in Fe oxidation state may not be directly related to changes in blue color but could be linked to the partial dissolution of Fe-bearing inclusions.

Ceria-supported Ni catalyst with high catalytic activity, selectivity and stability for CO2 conversion to CH4 by hydrogenation reaction investigated by X-ray absorption spectroscopy

x%Ni/CeO2 (x = 3, 6, 9, 12 and 18 wt%) catalysts were synthesized for CO2 methanation reaction. The catalysts were prepared via sol-gel method with co-adding of citric acid to improve Ni dispersion. 18 wt%Ni/CeO2 exhibited the highest catalytic performance. An in-situ experiment during CO2 methanation for monitoring the oxidation state changes of Ni and Ce was conducted by TRXAS. The oxidation states of Ni2+ and Ce4+ were reduced upon increasing the reduction temperature. Moreover, Nio and Ce3+ remained unchanged during reaction. The operando XAS experiment was performed to investigate the electronic state changes of Ni species during fluctuating conditions. The state of Nio remained unchanged upon H2 dropout and re-purging, which indicated that Ni species were completely re-reduced after H2 was added into the feed stream again. The completely reduced behavior of Ni active species was caused by highly dispersed Ni by the addition of citric acid.

Estimated Glycation End Products and Oxidative Status in Renal Failure Patients

The present study conducted to assess the Glycation end products and oxidative status of in patients with renal failure. 100 patients that have had CKD for less than 2 years have been diagnosed by a doctor. A control group of 40 stable individuals was selected. From October 2021 to February 2022, patients were confirmed to be sick with chronic renal disease at Azadi Teaching Hospital and Al-Jumhuri Hospital. ‎the results showed that the largest age group of patients was &gt; 60 years with percent (39%). Body Mass Index (BMI) of patients was 18.5-24.9 kg with percent (52%). Residential Area of patients was urban with percent (83%). Smoking Status of patients was non-smoking with percent (68%). The current outcomes demonstrated a reduction in the concentration of total protein that is significant (P&lt;0.05), albumin and globulin in patients compare with healthy volunteers. On the other hand, the results show a significant (P&lt;0.05) elevated in levels of carbonyl and amino group, while decreased in thiol levels in patients compare with healthy volunteers. Otherwise, the Glycation level shows significant (P&lt;0.05) elevated in in patients compare with healthy volunteers. Its concluded that the CKD lead to elevated Glycation level and changes in oxidative status.

Water-Mediated Charge Transfer and Electron Localization in a Co3Fe2 Cyanide-Bridged Trigonal Bipyramidal Complex.

The effects of temperature and chemical environment on a pentanuclear cyanide-bridged, trigonal bipyramidal molecular paramagnet have been investigated. Using element- and oxidation state-specific near-ambient pressure X-ray photoemission spectroscopy (NAP-XPS) to probe charge transfer and second order, nonlinear vibrational spectroscopy, which is sensitive to symmetry changes based on charge (de)localization coupled with DFT, a detailed picture of environmental effects on charge-transfer-induced spin transitions is presented. The molecular cluster, Co3Fe2(tmphen)6(μ-CN)6(t-CN)6, abbrev. Co3Fe2, shows changes in electronic behavior depending on the chemical environment. NAP-XPS shows that temperature changes induce a metal-to-metal charge transfer (MMCT) in Co3Fe2 between a Co and Fe center, while cycling between ultrahigh vacuum and 2 mbar of water at constant temperature causes oxidation state changes not fully captured by the MMCT picture. Sum frequency generation vibrational spectroscopy (SFG-VS) probes the role of the cyanide ligand, which controls the electron (de)localization via the superexchange coupling. Spectral shifts and intensity changes indicate a change from a charge delocalized, Robin-Day class II/III high spin state to a charge-localized, class I low spin state consistent with DFT. In the presence of a H-bonding solvent, the complex adopts a localized electronic structure, while removal of the solvent delocalizes the charges and drives an MMCT. This change in Robin-Day classification of the complex as a function of chemical environment results in reversible switching of the dipole moment, analogous to molecular multiferroics. These results illustrate the important role of the chemical environment and solvation on underlying charge and spin transitions in this and related complexes.

Dynamic Copper Site Redispersion through Atom Trapping in Zeolite Defects.

Single-site copper-based catalysts have shown remarkable activity and selectivity for a variety of reactions. However, deactivation by sintering in high-temperature reducing environments remains a challenge and often limits their use due to irreversible structural changes to the catalyst. Here, we report zeolite-based copper catalysts in which copper oxide agglomerates formed after reaction can be repeatedly redispersed back to single sites using an oxidative treatment in air at 550 °C. Under different environments, single-site copper in Cu-Zn-Y/deAlBeta undergoes dynamic changes in structure and oxidation state that can be tuned to promote the formation of key active sites while minimizing deactivation through Cu sintering. For example, single-site Cu2+ reduces to Cu1+ after catalyst pretreatment (270 °C, 101 kPa H2) and further to Cu0 nanoparticles under reaction conditions (270-350 °C, 7 kPa EtOH, 94 kPa H2) or accelerated aging (400-450 °C, 101 kPa H2). After regeneration at 550 °C in air, agglomerated CuO was dispersed back to single sites in the presence and absence of Zn and Y, which was verified by imaging, in situ spectroscopy, and catalytic rate measurements. Ab initio molecular dynamics simulations show that solvation of CuO monomers by water facilitates their transport through the zeolite pore, and condensation of the CuO monomer with a fully protonated silanol nest entraps copper and reforms the single-site structure. The capability of silanol nests to trap and stabilize copper single sites under oxidizing conditions could extend the use of single-site copper catalysts to a wider variety of reactions and allows for a simple regeneration strategy for copper single-site catalysts.

In Situ UV-Vis-NIR Absorption Spectroscopy and Catalysis.

This review highlights in situ UV-vis-NIR range absorption spectroscopy in catalysis. A variety of experimental techniques identifying reaction mechanisms, kinetics, and structural properties are discussed. Stopped flow techniques, use of laser pulses, and use of experimental perturbations are demonstrated for in situ studies of enzymatic, homogeneous, heterogeneous, and photocatalysis. They access different time scales and are applicable to different reaction systems and catalyst types. In photocatalysis, femto- and nanosecond resolved measurements through transient absorption are discussed for tracking excited states. UV-vis-NIR absorption spectroscopies for structural characterization are demonstrated especially for Cu and Fe exchanged zeolites and metalloenzymes. This requires combining different spectroscopies. Combining magnetic circular dichroism and resonance Raman spectroscopy is especially powerful. A multitude of phenomena can be tracked on transition metal catalysts on various supports, including changes in oxidation state, adsorptions, reactions, support interactions, surface plasmon resonances, and band gaps. Measurements of oxidation states, oxygen vacancies, and band gaps are shown on heterogeneous catalysts, especially for electrocatalysis. UV-vis-NIR absorption is burdened by broad absorption bands. Advanced analysis techniques enable the tracking of coking reactions on acid zeolites despite convoluted spectra. The value of UV-vis-NIR absorption spectroscopy to catalyst characterization and mechanistic investigation is clear but could be expanded.

The effect of slow-release vaginal dinoprostone on maternal and fetal oxidative stress in term pregnancies complicated by oligohydramnios: Prospective cohort study.

To evaluate changes in oxidant status using thiol/disulfide homeostasis in mothers and fetuses after induction of labor with slow-release vaginal dinoprostone inserts. A total of 70 pregnant women were divided into two groups. Thirty-five women in whom labor was induced with slow-release vaginal dinoprostone inserts (10 mg of prostaglandin E2, group A) were compared before and after the administration. The other 35 women, who were followed up spontaneously during labor (group B), were included as a control group. Both groups were diagnosed with isolated oligohydramnios without signs of placental insufficiency. The thiol/disulfide homeostasis parameters were calculated before medical induction and after removal of the insert at the beginning of the active phase of labor. Maternal and cord blood values were measured in both groups. Although the balance shifted to the antioxidant side after the slow-release vaginal dinoprostone insert was applied, there was no significant difference in maternal oxidative load compared to the pre-application status (5.32 ± 014/5.16 ± 0.15, p = 0.491). Despite the shift toward the antioxidant side, maternal antioxidants were still significantly lower in the group that received slow-release vaginal dinoprostone at the beginning of the active phase of labor than in the control group (295.98 ± 13.03/346.47 ± 12.04, respectively, p = 0.009). There was no statistically significant difference in terms of oxidative balance or newborn Apgar score ( p > 0.05). Induction of labor with slow-release vaginal dinoprostone inserts in pregnancies with isolated oligohydramnios does not cause further oxidative stress and is safe for both mothers and neonates in terms of oxidant load by thiol/disulfide homeostasis.