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Ionizing irradiation was performed on barium–germanium–gallium (BGG) glasses using a 2.5 MeV electron beam. Through electron spin resonance spectroscopy, paramagnetic point defects, such as germanium- and gallium-related electron and hole trap centers, have been identified. The presence of silver in the BGG glass appears to hinder the stability of these defects at lower energy doses (104 Gy), with silver becoming the main trapping center. At higher energy doses (106 Gy), the glass undergoes structural modifications, hindering the trapping process of silver ions. Additionally, we evidence the importance of alkaline elements such as potassium and sodium on silver ions trapped centers' formation. [ABSTRACT FROM AUTHOR]

Zinc germanium diphosphide (ZnGeP2) is a ternary semiconductor best known for its nonlinear optical properties. A primary application is optical parametric oscillators operating in the mid-infrared region. Controlled donor doping provides a method to minimize the acceptor-related absorption bands that limit the output power of these devices. In the present study, a ZnGeP2 crystal is doped with selenium during growth. Selenium substitutes for phosphorus and serves as a deep donor. Significant concentrations of native defects (zinc vacancies, germanium-on-zinc antisites, and phosphorous vacancies) are also present in the crystal. Electron paramagnetic resonance (EPR) is used to establish the atomic-level model for the neutral charge state of the selenium donor. The S = 1/2 signal from the neutral donors is produced at 6 K by illuminating with 633 nm light (electrons excited from doubly ionized Zn vacancies convert Se P + donors to Se P 0 donors). A g matrix, with principal values of 2.088, 2.203, and 1.904, is extracted from the angular dependence of the EPR spectrum. The principal-axis direction associated with the 1.904 principal value is close to a Se–Ge bond. This indicates an asymmetric distribution of unpaired spin density around the selenium ion and thus predicts the deep donor behavior. [ABSTRACT FROM AUTHOR]

The biological reduction of N2 to ammonia requires the ATP-dependent, sequential delivery of electrons from the Fe protein to the MoFe protein of nitrogenase. It has been demonstrated that CdS nanocrystals can replace the Fe protein to deliver photoexcited electrons to the MoFe protein. Herein, light-activated electron delivery within the CdS:MoFe protein complex was achieved in the frozen state, revealing that all the electron paramagnetic resonance (EPR) active E-state intermediates in the catalytic cycle can be trapped and characterized by EPR spectroscopy. Prior to illumination, the CdS:MoFe protein complex EPR spectrum was composed of a S = 3/2 rhombic signal (g = 4.33, 3.63, and 2.01) consistent with the FeMo-cofactor in the resting state, E0. Illumination for sequential 1-h periods at 233 K under 1 atm of N2 led to a cumulative attenuation of E0 by 75%. This coincided with the appearance of S = 3/2 and S = 1/2 signals assigned to two-electron (E2) and four-electron (E4) reduced states of the FeMo-cofactor, together with additional S = 1/2 signals consistent with the formation of E6 and E8 states. Simulations of EPR spectra allowed quantification of the different E-state populations, along with mapping of these populations onto the Lowe–Thorneley kinetic scheme. The outcome of this work demonstrates that the photochemical delivery of electrons to the MoFe protein can be used to populate all of the EPR active E-state intermediates of the nitrogenase MoFe protein cycle. [ABSTRACT FROM AUTHOR]

A stable three coordinate Cu(I)-radical complex with an S3 donor set having the general formula of [CuI(S–NHCH)(SS–NHC＝S)] (1) was isolated as dark blue needles. Interestingly, this complex possesses a zwitterionic ligand, −S–NHCH+, which is coordinated to the central Cu(I) ion via its S-atom [−S–NHCH+ ＝C4-thiolate functionalized C2-protonated zwitterionic N-hetero cyclic carbene; SS–NHC＝S˙− ＝NHC-based dithiolene radical anion]. 1 has been structurally characterized by single-crystal X-ray diffraction, and further characterized by UV-vis, IR, XPS, and EPR spectroscopy. 1 has also been studied by quantum chemical calculations. [ABSTRACT FROM AUTHOR]

The isolation of a stable persistent carbazole-stabilized boron-centered monoradical anion 1˙−, which has a high spin density at the B atom, has been reported. It is characterized using the crystal structure and UV-vis absorption spectrum, as well as electron paramagnetic resonance spectroscopy. Interestingly, the B–N bond was activated by the boron-centered radical anion 1˙−, which had not been reported before. [ABSTRACT FROM AUTHOR]

In recent years, there has been a surge in the production of kombucha—a functional beverage obtained via microbial fermentation of tea. However, fresh, unpasteurized kombucha is sensitive to quality deterioration as a result of, among other factors, oxidation. The addition of hops seems to be promising, due to their antioxidative properties, which may improve the stability of kombucha. However, aiming at retaining the highest antioxidative properties of kombucha, it remains unclear at which stage of the production process hops should be added. The study investigated the effect of hop supplementation during kombucha production on the basic physicochemical, antioxidative, and sensory properties of kombucha. Cascade hops in the concentrations 0.5 and 2 g/L were added at the onset of tea infusion and to the fresh, unpasteurized kombucha. The addition of hops (particularly at the pre-fermentation stage of production) led to a significant decrease in radical formation in the produced kombucha measured by electron spin resonance spectroscopy (ESR), which correlated with the higher DPPH antiradical activity and the elevated bitter α-acid content. From the sensory perspective, the post-fermentation addition of hops to kombucha resulted in a significantly higher rating of the overall quality. This enhancement was directly associated with heightened bitterness, increased presence of fruity and citrusy aromas, and a simultaneous reduction in the intensities of acetic and tea-related attributes. The data presented in this study are relevant for kombucha producers, who want to deliver a sensory-novel product in combination with an improved oxidative stability. Key points: • Hop addition in kombucha production improves the antioxidative activity of the beverage. • Hop α-acids display higher antioxidative properties in kombucha than polyphenols. • Oxidative stability of kombucha fortified with hops depends on the timing of hops addition. • Hop addition enriches the taste and aroma attributes of kombucha. [ABSTRACT FROM AUTHOR]

Ceramic fuel cells (CFCs) operating at high temperatures face several challenges, including material degradation and other related issues. Conversely, reducing the operating temperature diminishes performance due to the limited ionic conductivity of the electrolyte materials. The wide bandgap semiconductor electrolyte SrTiO 3 has enhanced electrical characteristics. Infrequent studies on semiconductor tuning to ionic conductors are looked at for use in ceramic fuel cells (CFCs). Here, we present a comprehensive survey of lithium-coating SrTiO 3 , or Li–SrTiO 3 , and its successful application in electrolytes for fuel cells. This research explores the feasibility of employing Li-coated SrTiO 3 with ionic-conductivity of 0.17 S/cm at 550 °C, and as the electrolyte demonstrated excellent fuel cell performance of 720 mW/cm2 at 550 °C, shedding light on its potential electrolytes to enhance fuel cell performance. Moreover, the perovskite structure shows higher oxygen vacancy (Ov) and lower activation energy (Ea), facilitating ion transport. The sol-gel technique is utilized to synthesize the powder. The structural, morphological, and surface properties of perovskite crystalline structure are thoroughly investigated using characterization techniques, including X-ray diffraction (XRD), Ultraviolet–visible, X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR), Raman, and Electrochemical impedance spectroscopy (EIS), elucidate the structural modifications and the consequent improvements in low-temperature CFCs. The results suggest that Li-coating is a feasible approach to designing CFCs. [Display omitted] • Li-STO perovskite cubic structure was developed as the function of electrolyte. • Li-STO achieved ionic conductivity of 0.17 Scm−1 at 550 °C. • Fuel cell based on 7% Li-STO demonstrated high performance of 720 mWcm−2. • DRT analysis has been performed to study the ion kinetics. [ABSTRACT FROM AUTHOR]

Stable radicals have attracted increasing attention in recent years because of their unique electronic and optical characteristics. Aminoxyl radicals are one of the most widely studied stable radicals to date, but their applications in opto-functional materials have yet to be explored in detail. Our group previously reported the boron complexes of aminoxyl radicals exhibit near-infrared (NIR) absorption. In this work, an aminoxyl radical without boron-complexation was synthesized to elucidate the effects of boron coordination on the properties of the aminoxyl radicals. The results of electron spin resonance spectroscopy, ultraviolet-visible-NIR absorption measurements, and density functional theory calculations indicated that boron complexation facilitated spin delocalization over the radical p-frameworks. Furthermore, a p-extended aminoxyl radical-boron complex exhibited a significant wavelength-shift to longer wavelengths in the NIR-II absorption region, thereby reflecting its larger p-conjugated radical skeleton. [ABSTRACT FROM AUTHOR]

Cyclic alkyl(amino) carbene (cAAC)-supported phosphaalkenides (cAAC＝P)− have been employed as ligands for the isolation of two atomically precise mixed valence paramagnetic Ag I/012 Cl3, and Ag I/010 , nano-clusters [(Me2-cAAC＝P)6Ag12Cl3] (2), and [(Me2-cAAC＝P)6Ag10](NTf2)2 (4). 2 and 4 have been structurally characterized by single-crystal X-ray diffraction revealing the presence of three Ag0 atoms, nine AgI ions (2); and two Ag0 atoms, eight AgI ions (4), respectively. The clustering inorganic unit Ag12Cl3 in 2 has been found to be surrounded by six mono-anionic μ3-cAAC＝P moieties having 3-bar symmetry. 2 and 4 have been studied by cyclic voltammetry, UV-vis, ESI-MS, XPS, EPR spectroscopy, and DFT calculations. [ABSTRACT FROM AUTHOR]

The formation of a double S-scheme heterojunction in the MoS 2 @MoO 3 /(Cu+/g-C 3 N 4) ternary composites is responsible for preserving strong reduction ability of photogenerated electrons on the Cu+/g-C 3 N 4 and strong oxidation ability of photogenerated holes on the MoO 3 , which efficiently participated in the PMS activation and the mineralization the RhB. [Display omitted] • The MoS 2 @MoO 3 /(Cu+/g-C 3 N 4) ternary composites was prepared by a simple calcination method. • The double S-scheme heterojunction was responsible for the enhanced performance in the degradation of RhB. • The reactive species for oxidizing RhB were identified by free-radical trapping experiments and ESR spectra. • The possible degradation pathway was proposed according to DFT calculations and LC-MS tests. The construction of semiconductor heterojunction is an effective way for charge separation in photocatalytic degradation of pollutants. In this study, a novel MoS 2 @MoO 3 /(Cu+/g-C 3 N 4) ternary composites (MMCCN) was prepared via a simple calcination method. The as-prepared composites exhibited exceptional performance in activating peroxymonosulfate (PMS) for the degradation of rhodamine B (RhB). The activity testing results indicated that 99.41 % of RhB (10 mg·L−1, 10 mL) was effectively removed by the synergistic effect of composites photocatalyst (0.1 g·L−1) and PMS (0.1 g·L−1) under visible light irradiation for 40 min. Its reaction rate constant exceeded that of Cu+/g-C 3 N 4 , MoO 3 and MoS 2 by a factor of 3.56, 17.30 and 11.73 times, respectively. The crystal structure, band gap and density of states (DOS) of the semiconductors were calculated according to the density functional theory (DFT). Free radical trapping tests and electron spin resonance spectroscopy validated that 1O 2 , O 2 − and h+ are primary reactive species participating in the decomposition of RhB. The ternary composites demonstrated good stability and maintained excellent degradation efficiency even across four reaction cycles. Furthermore, the activation mechanism and the intermediates produced during the decomposition course of RhB by MMCCN/PMS/vis system were analyzed and elucidated. A double S-scheme heterojunctions was responsible for efficient separation of photo-induced electron-hole pairs. This work presents a novel method in the construction of double S-scheme heterojunctions for PMS activation which is expected to find wide applications in wastewater treatment and environmental remediation. [ABSTRACT FROM AUTHOR]

Metallacycles are structurally diverse molecular entities that have attracted significant research interest due to their potential applications in sensing, catalysis, and biomedicine. In this study, we report the synthesis of two discrete neutral Schiff base-derived dinuclear Cu(II) metallacycles [Cu2L2] (1) and [Cu2L′2] (2) achieved through coordination driven self-assembly using ligands N,N′-bis(3,5-di-tert-butylsalicylidene)-2,2′-diaminodiphenyl ether (H2L) and (N,N′-bis(3,5-di-tert-butylsalicylidene)-hydrazine) (H2L′), respectively. 1 and 2 are characterized by infrared, UV-vis, fluorescence, and electron paramagnetic resonance spectroscopy. The X-ray diffraction analysis confirms that 1 adopts a double helical structure while 2 exhibits a butterfly shape. The magnetic and electrochemical properties of metallacycles are investigated using superconducting quantum interference device (SQUID) magnetometry and cyclic voltammetry. The results revealed that the macrostructure of the metallacycles significantly influences their photophysical, magnetic and electronic properties. In addition, the catalytic efficiency of metallacycles towards ring-opening polymerization of ε-caprolactone is evaluated. [ABSTRACT FROM AUTHOR]

This work explores the synthesis and characterization of cobalt oxide-added borosilicate glass using the melt-quenching technique. The glass system was investigated using various methods, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), density measurements, UV–vis spectroscopy, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy. XRD validated the glass's amorphous nature, while FTIR results indicated significant bonding alterations, showing a transition from BO 3 to BO 4 units and from B 3 -O-Si to B 4 -O-Si linkages. The increased glass density further supported the formation of BO 4 units. XPS analysis verified the presence of Co2+ and Co3+ ions within the glass matrix. Optical absorption studies revealed distinct electronic transitions for Co2+ ions in both tetrahedral and octahedral coordination, and for Co3+ ions in octahedral coordination, which was corroborated by EPR spectroscopy. The paramagnetic nature of Co2+ ions was analyzed, and the g-value was determined using X-band frequency. The study also noted the narrowing of the indirect band gap with the rise in the content of Co 3 O 4 , and the examination of the metallization criterion suggested a potential metallic nature for the synthesized glasses. Notably, the 0.05 mol% Co 3 O 4 -added sample exhibited a 48 % transmission rate and the highest emission, highlighting its potential as an optical bandpass filter. These findings underscore the versatility and tunability of cobalt oxide-added borosilicate glass for various optical technologies. [Display omitted] • Structural and optical properties of Co 3 O 4 added in borosilicate glass were studied. • The electronic transitions revealed cobalt ions in both octahedral and tetrahedral coordination. • Co 3 O 4 added glass exhibit multiple absorption in visible region at 535, 570, and 634 nm. • The Co 3 O 4 -added glass can be employed as band-pass filter with a wide transmission range 325–600 nm. [ABSTRACT FROM AUTHOR]

• Nitric oxide is a potent, yet unrecognised, non-classical gaseous neurotransmitter. • In the context of epilepsy, nitric oxide persists as an enigmatic subject. • The nitrergic system engages in the acute brain response to epileptic activity. • The nitrergic system activation diminishes quickly after the occurrence of seizures. • This activation may serve as an antiepileptogenic compensatory mechanism. • Under usual conditions, this activation is insufficient to attenuate seizures. Epilepsy is a pathophysiological condition displaying a highly diverse phenotype. Consequently, comprehending the mechanisms underlying seizures necessitates moving beyond a simplistic model focused on the imbalance between the classical excitatory and inhibitory neurotransmitter systems. Nitric oxide (NO), a nonclassical and multifunctional gaseous neurotransmitter, has the potential to exert a profound influence on epileptic reactivity. Unfortunately, numerous studies have not provided clear answers about its involvement in the pathophysiology of epilepsy. The objective of our study was to delineate the temporal dynamics of alterations in nitrergic system activation after experimentally induced seizures. Seizures were induced in 2-month-old male Wistar rats (n = 55) by an administration of pilocarpine. Over a 6-hour observation period, seizure behaviour intensity was continuously evaluated using a modified Racine scale. At intervals of 6, 12, 24, 48, or 96 h post-chemoconvulsant administration, NO spin trapping was conducted with ferrous-diethyldithiocarbamate complexes (Fe(DETC) 2). Electron paramagnetic resonance (EPR) spectroscopy was employed to quantify mononitrosyl iron complexes (NO-Fe(DETC) 2) in the brain. The temporal kinetic of NO release after seizures revealed a rise in NO synthesis during the initial 12 h. Subsequently, a sharp decline occurred, returning to baseline 96 h after pilocarpine injection. Notably, our research suggests that the level of NO synthesis does not interfere with the severity of the epileptic seizures that occur. In light of this, we propose that the nitrergic system is quickly activated in the epileptic brain as a compensatory mechanism of the central nervous system. However, under usual conditions, this activation is insufficient to effectively attenuate seizures. [ABSTRACT FROM AUTHOR]

In subsurface water, humic acid (HA) can react with active chlorine to form carcinogenic compounds, posing ecological issues and health risks. This study aims to create sludge activated carbon (SAC), combine it with Fe2+, and activate peroxosulfate (PMS) to remove HA from water. To verify the successful modification of SAC, the physicochemical properties were characterized using various methods such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Brunauer Emmett Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). Moreover, in the Fe2+/SAC/PMS system, the removal rate of HA rose significantly, peaking at 96%. The removal of HA conformed to the first-order reaction kinetic equation, with a reaction rate constant of 0.048 min-1, showing that activated PMS generates potent oxidative radicals or non-radicals, boosting reaction efficiency. After four repeated cycles of use, the removal rate of HA remained above 90%, demonstrating its excellent stability and reusability. The results of three-dimensional fluorescence spectroscopy (3D-EEM) indicated that the Fe2+/SAC/PMS system could effectively degrade dissolved organic matter (DOM) in water. Quenching experiments and electron paramagnetic resonance (EPR) analysis further confirmed that singlet oxygen (1O2) is the primary oxidative species for degrading HA. Therefore, the Fe2+/SAC/PMS reaction system presented promising application prospects to remove HA from water. [ABSTRACT FROM AUTHOR]

NH 2 -MIL-88B(Fe)/CuInS 2 S-scheme heterojunction as iron-copper bimetallic photo-Fenton system is fabricated via a straightforward hydrothermal process. It shows excellent photothermal-photocatalytic Fenton property for degradation of tetracycline in low-temperature wastewaters, due to the synergistic effect of bimetallic codoped Fenton system and formation of S-scheme heterojunction. [Display omitted] Enhancing the velocity of the oxidation–reduction cycle is crucial for improving the catalytic efficiency of Fenton processes. Therefore, the development of an effective strategy for wastewater degradation at low temperatures is essential. In this context, we present the preparation of an NH 2 -MIL-88B (Fe)/CuInS 2 S-scheme heterojunction. Specifically, CuInS 2 nanoparticles are introduced onto the Ferro-organic skeleton, resulting in the exposure of a significant number of active surface sites. Furthermore, NH 2 -MIL-88B (Fe)/CuInS 2 demonstrates an extended photoresponse into the long-wavelength region, which contributes to its excellent photothermal properties. Notably, the degradation rate of tetracycline in low-temperature aqueous environments reaches as high as 99.7 %, several times higher than that of the original sample. Additionally, the hydrogen production of NH 2 -MIL-88B (Fe)/CuInS 2 is 2.23 times that of single NH 2 -MIL-88B (Fe) and 3.46 times that of single CuInS 2. Moreover, the system exhibits good H 2 O 2 evolution performance, forming an efficient photo-Fenton system. The charge transfer process in S-scheme heterojunction is confirmed using in-situ X-ray photoelectron spectroscopy and electron paramagnetic resonance. Both transient photoluminescence and photo electrochemical tests further validate the enhanced photoelectrochemical properties of the NH 2 -MIL-88B (Fe)/CuInS 2 S-scheme heterojunction. The exceptional performance of this system can be attributed to the synergistic effects of the S-scheme heterojunction and the bimetallic codoped photo-Fenton system. This research presents a novel approach for the breakdown of low-temperature wastewater using an improved photocatalytic Fenton system. [ABSTRACT FROM AUTHOR]

[Display omitted] The research in the field of photocatalysis has progressed, with the development of heterojunctions being recognized as an effective method to improve carrier separation efficiency in light-induced processes. In this particular study, CuCo 2 S 4 particles were attached to a new cubic CdS surface to create an S-scheme heterojunction, thus successfully addressing this issue. Specifically, owing to the higher conduction band and Fermi level of CuCo 2 S 4 compared to CdS, they serve as the foundation and driving force for the formation of an S-scheme heterojunction. Through in-situ X-ray photoelectron spectroscopy and electron paramagnetic resonance analysis, the direction of charge transfer in the composite photocatalyst under light exposure was determined, confirming the charge transfer mechanism of the S-scheme heterojunction. By effectively constructing the S-scheme heterojunction, the d-band center of the composite photocatalyst was adjusted, reducing the energy needed for electron filling in the anti-bonding energy band, promoting the transfer of photogenerated carriers, and ultimately enhancing the photocatalytic hydrogen production. performance. After optimization, the hydrogen evolution activity of the composite photocatalyst CdS-C/CuCo 2 S 4 -3 reached 5818.9 μmol g−1h−1, which is 2.6 times higher than that of cubic CdS (2272.3 μmol g−1h−1) and 327.4 times higher than that of CuCo 2 S 4 (17.8 μmol g−1h−1), showcasing exceptional photocatalytic activity. Electron paramagnetic resonance and in situ X-ray photoelectron spectroscopy have established a theoretical basis for designing and constructing S-scheme heterojunctions, offering a viable method for adjusting the D-band center to enhance the performance of photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

Background: Gentamicin (GM) administration is associated with decreased metabolism, increased oxidative stress, and induction of nephrotoxicity. Sambucus nigra L., containing flavonoids, anthocyanins, and phytosterols, possesses antioxidant and anti-inflammatory potential. Objectives: The present study aimed to investigate the nephroprotective and anti-inflammatory potential of lyophilized Sambucus nigra fruit extract (S. nigra extract) to reduce acute oxidative stress and residual toxicity of GM in a 7-day experimental model in Balb/c rodents. Methods: The S. nigra extract was lyophilized (300 rpm; 10 min; −45 °C) to improve pharmacological properties. Balb/c mice were divided into four (n = 6) groups: controls; S. nigra extract per os (120 mg kg−1 day−1 bw); GM (200 mg kg−1 day−1 bw) (4); and GM + S. nigra therapy. The activities of antioxidant and renal enzymes, cytokines, and levels of oxidative stress biomarkers—Hydroxiproline, CysC, GST, KIM-1, PGC-1α, MDA, GSPx—were analyzed by ELISA tests. The ROS and RNS levels, as well as 5-MSL-protein oxidation, were measured by EPR spectroscopy. Results: The antioxidant-protective effect of S. nigra extract (120 mg kg−1) was demonstrated by reduced MDA, ROS, and RNS and increased activation of endogenous enzymes. Furthermore, S. nigra extract significantly reduced the expression of IL-1β, IL-6, IL-10, TNF-α, IFN-γ, and KIM-1 and regulated collagen/protein (PGC-1α and albumin) deposition in renal tissues. Conclusions: Histological evaluation confirmed that S. nigra (120 mg kg−1) attenuated renal dysfunction and structural damage by modulating oxidative stress and acute inflammation and could be used as an anti-fibrotic alternative in GM nephrotoxicity. [ABSTRACT FROM AUTHOR]

Food-grade titanium dioxide (E171) is widely used in food, feed, and pharmaceuticals for its opacifying and coloring properties. This study investigates the formation of reactive oxygen species (ROS) and the aggregation behavior of E171 using the TNO Gastrointestinal (GI) model, which simulates the stomach and small intestine. E171 was characterized using multiple techniques, including electron spin resonance spectroscopy, single-particle inductively coupled plasma–mass spectrometry, transmission electron microscopy, and dynamic light scattering. In an aqueous dispersion (E171-aq), E171 displayed a median particle size of 79 nm, with 73–75% of particles in the nano-size range (<100 nm), and significantly increased ROS production at concentrations of 0.22 and 20 mg/mL. In contrast, when E171 was mixed with yogurt (E171-yog), the particle size increased to 330 nm, with only 20% of nanoparticles, and ROS production was inhibited entirely. After GI digestion, the size of dE171-aq increased to 330 nm, while dE171-yog decreased to 290 nm, with both conditions showing a strongly reduced nanoparticle fraction. ROS formation was inhibited post-digestion in this cell-free environment, likely due to increased particle aggregation and protein corona formation. These findings highlight the innate potential of E171 to induce ROS and the need to consider GI digestion and food matrices in the hazard identification/characterization and risk assessment of E171. [ABSTRACT FROM AUTHOR]

In this study, a novel Z-scheme heterojunction photocatalyst was developed by integrating g-C3N4 nanoplates into ZnIn2S4 microspheres. X-ray photoelectron spectroscopy analysis revealed a directional electron transfer from g-C3N4 to ZnIn2S4 upon heterojunction formation. Under irradiation, electrochemical tests and electron paramagnetic resonance spectroscopy demonstrated significantly enhanced charge generation and separation efficiencies in the ZnIn2S4/g-C3N4 composite, accompanied by reduced charge transfer resistance. In photocatalytic CO2 reduction, the ZnIn2S4/g-C3N4 composite achieved the highest CO yield, 1.92 and 5.83 times higher than those of pristine g-C3N4 and ZnIn2S4, respectively, with a notable CO selectivity of 91.3% compared to H2 (8.7%). The Z-scheme heterojunction mechanism, confirmed in this work, effectively preserved the strong redox capabilities of the photoinduced charge carriers, leading to superior photocatalytic performance and excellent long-term stability. This study offers valuable insights into the design and development of g-C3N4-based heterojunctions for efficient solar-driven CO2 reduction. [ABSTRACT FROM AUTHOR]

Ctr1 is a membrane-spanning homotrimer that facilitates copper uptake in eukaryotic cells with high affinity. While structural details of the transmembrane domain of human Ctr1 have been elucidated using X-ray crystallography and cryo-EM, the transfer mechanisms of copper and the conformational changes that control the gating mechanism remain poorly understood. The role of the extracellular N-terminal domains is particularly unclear due to the absence of a high-resolution structure of the full-length hCtr1 protein and limited biochemical and biophysical characterization of the transporter in solution and in cell. In this study, we employed distance electron paramagnetic resonance to investigate the conformational changes of the extracellular N-terminal domain of full-length hCtr1, both in vitro and in cells, as a function of Cu(I) binding. Our results demonstrate that at specific Cu(I) concentrations, the extracellular chains move closer to the lumen to facilitate copper transfer. Additionally, while at these concentrations the intracellular part is penetrating the lumen, suggesting a ball-and-chain gating mechanism. Moreover, this phenomenon was observed for both reconstituted protein in micelles and in native cell membranes. However, the measured distance values were slightly different, suggesting that the membrane's characteristics and therefore its lipid composition also impact and even regulate the gating mechanism of hCtr1. [ABSTRACT FROM AUTHOR]

Cold atmospheric plasma (CAP) enables painless tissue treatment by producing reactive species including excited molecules and charged particles and is of great interest for medical applications. Medical CAP sources work in contact with air at ambient pressure, resulting in the generation of substantial amounts of reactive oxygen and nitrogen radicals. These radicals have a significant influence on cellular biochemistry, are crucial components of the immune system, and play a central role in wound therapy. CAP has a variety of applications, with a particular emphasis on tissue treatment in dermatology. It eradicates microorganisms by preventing biofilm formation so that wounds can be effectively disinfected and treated antiseptically. Using both in vitro and ex vivo methods, a comprehensive preclinical assessment of a novel battery-operated cold plasma handheld device with a reusable, and autoclavable glass cylinder was performed. The objectives were to evaluate the potential impact of single CAP application on radical formation with and without wound dressing, by directly measuring radicals in skin, to investigate the influence of CAP application on antimicrobial activity and cytotoxicity in vitro , and to assess skin tolerance ex vivo. The direct effect of CAP on the formation of radicals in the skin after plasma application at different levels with and without wound dressing was demonstrated quantitatively for the first time using electron paramagnetic resonance spectroscopy. Free radicals were measured in the skin as a function of the duration of CAP treatment. Furthermore, it was found that an alginate or wound plaster dressing does not significantly inhibit radical formation in skin compared to application without a dressing. In vitro and ex vivo data showed no cytotoxic potential with simultaneous efficacy against bacteria strains and no risk of temperature rise, pH change, skin barrier or DNA damage. These results show a high potential for wound healing applications in vivo. [Display omitted] • The presented CAP is skin save according to the draft standard DIN SPEC 91315 methods. • The CAP shows good antimicrobial activity. • CAP induce free radicals in the skin increasing with power and time of application. • The radicals are still detectable through two different wound dressings. [ABSTRACT FROM AUTHOR]

This study investigated the influence of the ZnO morphology on the energy storage capacity of symmetric supercapacitor devices, focusing on the defect centers present in the materials due to morpho-structural differences. Thus, ZnOs with five different morphologies were synthesized with varying methods in which the nanoparticles have the form of flowers, bullets, pyramids, hexagons, and rods. All materials were thoroughly characterized by scanning/transmission electron microscopy, X-ray diffraction, and spectroscopic techniques like photoluminescence, UV–Vis, Raman, and electron paramagnetic resonance spectroscopy. Subsequently, the ZnO-based materials were assembled in symmetric supercapacitor devices to test their energy storage capabilities. The ZnO with nanorod and hexagonal morphologies showed the best specific capacity (180 and 142 F/g), energy density (25 and 19 Wh/kg), and power density (211 and 252 kW/kg) values. The importance of the defect centers in the materials was highlighted, where the ratio between the Zn and O vacancies, evidenced by EPR spectroscopy, plays a crucial role in the ZnO materials' energy storage capacity. The Raman results support the proposed model, which underlines the importance of oxygen vacancies. In contrast, BET measurements show that the specific surface area of the morphologically distinct ZnO materials does not change drastically, validating the importance of the defect centers in the materials. A so-called "bottle-neck" effect is proposed to describe the relation between the paramagnetic vacancies and the electric properties of the materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Cerium‐doped SrTiO3 ceramics (Sr1‐3x/2CexTiO3, x = 0, 0.005, 0.0075, 0.01, 0.0125, and 0.015) were prepared by a burying sintering process. The sample with x = 0.0075 exhibits a colossal permittivity (∼ 21,000) and ultra‐low dielectric loss (∼ 0.0073) at room temperature (at 1 kHz). Furthermore, the x = 0.0075 sample maintains high permittivity (ε′ ≥ 15,000) and low dielectric loss (tanδ ≤ 0.018) in a wide temperature range (−60°C to 250°C). X‐ray photoelectron spectroscopy and electron paramagnetic resonance indicate the coexistence of Ce3+ and Ti3+. According to equation C=εAd$C = \frac{{\varepsilon A}}{d}$, synergetic effects from defect dipoles and interfacial polarization are responsible for the observed high‐performance giant permittivity behaviors with pronounced temperature stability and ultralow tanδ. The dielectric behaviors under different DC biases evidence the minor contribution from the interfacial polarization and reflect the dominant contribution from defect dipoles. The dielectric properties of dielectric ceramics are mainly influenced by oxygen vacancy clusters and defect dipoles ((Ti3+ − VO••${\mathrm{V}}_O^{ \bullet \bullet }$ − Ti3+) and (VSr′′${\mathrm{V}}_{{\mathrm{Sr}}}^{{\mathrm{^{\prime\prime}}}}$ − VO••${\mathrm{V}}_O^{ \bullet \bullet }$)). The excellent thermal stability of permittivity is also attributed to the pinning effect of defect dipoles from the charged defects which prohibit the long‐range movement of free carries. The obtained colossal permittivity and low dielectric loss SrTiO3‐based ceramics with high‐frequency/temperature stabilities are suitable for the application of single‐layer ceramic capacitors. [ABSTRACT FROM AUTHOR]

The present study reports the development of ternary and quaternary carbon nitride (CN) based nanocomposites through the coupling of CN with single-walled carbon nanotubes (SWCNTs), Ag3PO4 (AP) and Ag nanoparticles (NP). A facile wet-chemistry process was developed for the synthesis of the composites. The prepared materials were characterised using XRD, ATR, DR-UV-Vis, photoluminescence (PL) spectroscopy and EPR. Photocatalytic dye degradation (rhodamine b, RhB) is greatly improved in composite materials. The most active photocatalyst was the quaternary composite bearing SWCNTs, Ag3PO4 and Ag NP, that presented a 2- and a 3-fold increase in photoactivity compared with the CN functionalised only with SWCNTs and the pure CN, respectively. The enhanced activity is associated with improvements in several important materials properties. Adsorption in the visible light is improved by the presence of Ag3PO4 and Ag NP. The latter provided plasmon resonance effects, absorbing light up to 700 nm. The presence of SWCNTs reduced charge recombination phenomena reducing by half the PL intensity. In addition, charge availability was further increased due to the formation of heterojunctions through the coupling of CN with Ag3PO4 and Ag NP. The PL intensity of the ternary composite was reduced to 1% of the pure CN PL intensity. In-situ EPR spectroscopy using spin-traps revealed the formation of superoxide anion radicals ($${\rm{O}}_2^{ \bullet - }$$ O 2 ∙ − ) that provide evidence for charge transfer via a Z-scheme mechanism. $${\rm{O}}_2^{ \bullet - }$$ O 2 ∙ − production was enhanced 8.5 times in the ternary composite compared with the pure CN. The importance of the stepwise functionalization of CN through the formation of ternary and quaternary composites towards the development of advanced photoactive materials is highlighted herein. [ABSTRACT FROM AUTHOR]

In‐cell measurements of the relationship between structure and dynamics to protein function is at the forefront of biophysics. Recently, developments in EPR methodology have demonstrated the sensitivity and power of this method to measure structural constraints in‐cell. However, the need to spin label proteins ex‐situ or use noncanonical amino acids to achieve endogenous labeling remains a bottleneck. In this work we expand the methodology to endogenously spin label proteins with Cu(II) spin labels and describe how to assess in‐cell spin labeling. We quantify the amount of Cu(II)‐NTA in cells, assess spin labeling, and account for orientational effects during distance measurements. We compare the efficacy of using heat‐shock and hypotonic swelling to deliver spin label, showing that hypotonic swelling is a facile and reproducible method to efficiently deliver Cu(II)‐NTA into E. coli. Notably, over six repeats we accomplish a bulk average of 57 μM spin labeled sites, surpassing existing endogenous labeling methods. The results of this work open the door for endogenous spin labeling that is easily accessible to the broader biophysical community. [ABSTRACT FROM AUTHOR]

Alcoholysis of Cp′3Ln (Ln = La, Ce; Cp′ = C5H4SiMe3) generate high-yielding (72–97%) bimetallic LnIII complexes of [Cp′2Ln(μ-OR)]2 [R = Et, iPr, or C6H4-4-tBu]. Single-crystal X-ray diffraction of these complexes reveal unexpected decreases in Ln⋯Ln distances, increasing Cpcent–Ln–Cpcent angles, and increasing intermolecular C⋯C contacts with bulkier bridging alkoxides, in line with structural control driven by significant dispersion forces. 1H NMR spectroscopy of [Cp′2Ce(μ-OEt)]2 and [Cp′2Ce(μ-OiPr)]2 revealed significantly upfield resonances assigned as methylene and methine moieties of −43.74 and −70.85 ppm, respectively. 2D 1H DOSY NMR experiments of [Cp′2Ce(μ-OiPr)]2 in C6D6 supported a dimeric structure in solution, including in the presence of a Lewis base (i.e., THF). Reduction of [Cp′2La(μ-OiPr)]2 using KC8 in the presence of 2.2.2-cryptand at −78 °C generated a purple solution and X-band EPR spectroscopy revealed an eight-line hyperfine pattern indicative of a LaII species. [ABSTRACT FROM AUTHOR]

The primary objective of materials science is the study of the properties of the existing materials and the development of new ones. In the present day, the use of solid-state lasers abroad has prompted material scientists globally to develop novel or enhance the properties of the existing active gain media. Materials comprising rare earth elements have historically proven effective in scintillation applications. The synthesis of LaLu 1-x Yb x O 3 monodisperse nanopowders with a particle size of 50–62 nm via the Pechini complexing citrate method has been the subject of investigation using electron paramagnetic resonance (EPR) spectroscopy and photoluminescence (PL) measurements. The EPR data indicate that the Yb³⁺ ions predominantly create a single type of center, whereby the Yb³⁺ ion substitutes for the Lu³⁺ ion. The calculated EPR g-factors are estimated to be g 1 = 3.85, g 2 = 2.15, g 3 = 1.55 and the 171Yb isotope hyperfine interaction constants are A 1 = 600 × 10−4 cm−1, A 2 = 700 × 10−4 cm−1, A 3 ≈ 1800 × 10−4 cm−1. The principal values of the g factors and the hyperfine tensors indicate that the Yb site in LaLu 1-x Yb x O 3 nanopowders exhibits orthorhombic symmetry. The PL measurements in the wavelength range of 350–1800 nm, with excitation provided by either a xenon lamp or a diode laser, indicate the presence of a broad emission band, centered at 404 nm, in addition to the well-known emission spectrum in the IR region (920–1100 nm) arising from Yb3+ ions. [ABSTRACT FROM AUTHOR]

Background and Aims Hyperglycaemia during gestational diabetes (GD) predisposes women and their offspring to later cardiometabolic disease. The hyperglycaemia-mediated epigenetic changes remain to be elucidated. Methyltransferase MLL1-induced trimethylation of histone 3 at lysine 4 (H3K4me3) activates inflammatory and oxidative phenotype. This epigenetic mark in GD women and its transmission to the offspring were investigated. Methods Peripheral blood mononuclear cells (PBMC) were collected from GD and control (C) women and also from adolescents born to women of both groups. Endothelial human umbilical vein endothelial cells (HUVEC) and cord blood mononuclear cells (CBMC) were from umbilical cords. The NF-κBp65 and NOX4 expressions were investigated by reverse transcription quantitative polymerase chain reaction and immunofluorescence (IF). MLL1 and H3K4me3 were investigated by immunoblotting and IF. H3K4me3 on NF-κBp65 and NOX4 promoters was studied by chromatin immunoprecipitation. Superoxide anion generation was measured by electron spin resonance spectroscopy. Plasma cytokines were measured by enzyme-linked immunosorbent assay. To investigate the role of MLL1, HUVEC were exposed to inhibitor MM102 or siRNA transfection. Results PBMC, CBMC, and HUVEC showed an increase of NF-κBp65 , IL-6 , ICAM-1 , MCP-1 , and VCAM-1 mRNAs. These findings were associated with H3K4me3 enrichment in the promoter of NF-κBp65. Elevated H3K4me3 and cytokine levels were observed in GD adolescents. MLL1 drives H3K4me3 not only on NF-kB p65 , but also on NOX4 promoter. Inhibition of MLL1 blunted NF-κBp65 and NOX4 by modulating inflammatory and oxidative phenotype. Conclusions Such proof-of-concept study shows persistence of MLL1-dependent H3K4me3 in offspring born to GD women, suggesting an epigenetic-driven transmission of maternal phenotype. These findings may pave the way for pharmacological reprogramming of adverse histone modifications to mitigate abnormal phenotypes underlying early ASCVD. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrogen peroxide (H 2 O 2) is a crucial eco-friendly oxidizer with increasing demand due to its wide range of applications. Activating O 2 with catalysts to generate H 2 O 2 on-site offers a promising alternative to traditional production methods. Here, we design unique crystalline/amorphous heterophase Fe-Mn core–shell chains (ZVI-Mn) for efficient on-site generation of H 2 O 2 and manipulation of subsequent H 2 O 2 activation. The yield of H 2 O 2 on-site produced by ZVI-Mn in water within 5 min was 103.7 mg·L-1, which was much greater than that of zero-valent iron (ZVI) and amorphous Mn (A-Mn) (0 and 42.5 mg·L-1). Raman and density functional theory (DFT) calculations confirmed that *OOH is the key species involved in the on-site generation of H 2 O 2. Electrochemical tests confirmed the excellent electron-transferring ability, while electron paramagnetic resonance (EPR) revealed oxygen vacancy defects in the catalysts, which proved to be conducive to improving the catalytic activity of ZVI-Mn. Additionally, by regulating the pH of aqueous solution, ZVI-Mn can simultaneously achieve efficient on-site generation of H 2 O 2 and in-situ removal of enrofloxacin from aqueous solution. [ABSTRACT FROM AUTHOR]

The very first representative of trithia‐bridged N‐heterotriangulene, a triphenylamine with sulfur atoms bridging the ortho‐positions, was synthesized by a sequence of regioselective sulfenylation with phthalimidesulfenyl chloride followed by Lewis acid‐catalyzed electrophilic cyclization. X‐ray crystallography revealed a saddle‐shaped geometry of the polycyclic scaffold. UV/Vis absorption spectroscopy and cyclic voltammetry were used to characterize the optoelectronic properties. The title compound is a particularly strong electron donor forming a perfectly stable radical cation, which was analyzed by electron paramagnetic resonance spectroscopy and X‐ray crystallography. The electron donor properties were further highlighted by the formation of crystalline donor‐acceptor complexes with strong cyano‐based acceptors. [ABSTRACT FROM AUTHOR]

Apple pomace, a by-product of apple juice production, is typically discarded as waste. Recent approaches have focused on utilizing apple pomace by extracting beneficial bioactive compounds, such as antioxidant phenolic compounds (PCs). Before these PC-rich extracts can be used in food products, they must undergo food preservation and processing methods. However, the effects of these processes on the composition, stability, and properties of the PC remain insufficiently understood. The present study aimed at investigating the effects of a thermal treatment (TT), a high-pressure thermal treatment (HPTT), and a pulsed electric field treatment (PEF) on the composition and antioxidant activity of PC-rich apple pomace extracts (APEs). Major PCs, including phloridzin, chlorogenic acid, and epicatechin, as well as minor compounds, were identified by liquid chromatography–tandem mass spectrometry (LC-MS/MS) and high-performance thin-layer chromatography (HPTLC). As a stability indicative property, the antioxidant activity was analyzed by a Trolox equivalent antioxidant capacity assay (TEAC), electron paramagnetic resonance spectroscopy, and the Folin–Ciocalteu reagent assay. The results showed that TT at 80 °C increased phloridzin content, likely due to the hydrolysis of bound forms, while higher temperatures and HPTT resulted in a substantial PC conversion. The PEF treatment also caused notable PC conversion, but generally, it had a milder effect compared to TT and HPTT. Hence, low temperatures with and without high pressure and PEF seem to be the most promising treatments for preserving the highest content of major PC in APE. Antioxidant activity varied among the analytical methods, with HPTT showing minor changes despite PC loss compared to the untreated APE. This suggests that other antioxidant compounds in the extracts may contribute to the overall antioxidant activity. This study demonstrates that apple pomace contains valuable PC, highlighting its potential as a health-promoting food additive and the impact of conventional preservation and processing methods on PC stability. [ABSTRACT FROM AUTHOR]

Herein, a high selective epoxidation of isobutene was achieved by heterogeneously dispersed MoSe2 with tert-butyl hydroperoxide (TBHP), which further showed versatile substrate scopes and well-retained activity among recycling tests. A rational mechanism is proposed based on extensive control experiments and electron paramagnetic resonance spectroscopy, surprisingly unveiling the metal–oxo and radical mediated pathways dramatically accelerated by hydrogen bonds of hexafluoroisopropanol (HFIP). [ABSTRACT FROM AUTHOR]

The thermally assisted reaction of Cr(NO3)3·9H2O, 4-Cl-pzH, and Et3N yielded electrochemically active trinuclear CrIII–oxo–pyrazolate complexes with formula (Ph4P)2[Cr3(μ3-O)(μ-4-Cl-pz)6X3], X = Cl (1) and Br (2). Magnetic susceptibility measurements and EPR spectroscopy show that 1 has an antiferromagnetically coupled Cr3O-core with an S = 1/2 ground state and isotropic exchange of J = −12.7 cm−1. (Hex = −2JS1S2). Cyclic voltammetry reveals a facile reversible oxidation to the formally Cr III2 CrIV analogue of 1. The UV-Vis-NIR spectra of Cr III3 and Cr III2 CrIV species have been assigned with the help of DFT calculations. [ABSTRACT FROM AUTHOR]

The combination of continuous wave electron paramagnetic resonance (cw‐EPR) with electrochemistry is highly attractive as it allows a clean in‐situ generation and the subsequent spectroscopic characterisation of radical ions, which are important intermediates in many photocatalytic cycles as well as light‐induced processes occurring in biological systems or optoelectronic devices. Although commercial setups for spectroelectrochemical EPR are available, they are often expensive and tailored to a particular spectroscopic setup. Here we present a design for a low‐cost electrochemical EPR cell that can be used in combination with any commercial cw‐EPR instrumentation. The cell design is compared to existing setups and the performance of the cell is evaluated by comparison of EPR spectra obtained by chemical and electrochemical oxidation of a graphene fragment. [ABSTRACT FROM AUTHOR]

The thermally assisted reaction of Cr(NO3)3·9H2O, 4-Cl-pzH, and Et3N yielded electrochemically active trinuclear CrIII–oxo–pyrazolate complexes with formula (Ph4P)2[Cr3(μ3-O)(μ-4-Cl-pz)6X3], X = Cl (1) and Br (2). Magnetic susceptibility measurements and EPR spectroscopy show that 1 has an antiferromagnetically coupled Cr3O-core with an S = 1/2 ground state and isotropic exchange of J = −12.7 cm−1. (Hex = −2JS1S2). Cyclic voltammetry reveals a facile reversible oxidation to the formally Cr III2 CrIV analogue of 1. The UV-Vis-NIR spectra of Cr III3 and Cr III2 CrIV species have been assigned with the help of DFT calculations. [ABSTRACT FROM AUTHOR]

This work reports synthesis of a germylene based donor‐acceptor molecule and its thermal excitation to a triplet state by coordination with a Lewis acid. Products have been characterized by single crystal X‐ray diffraction, EPR spectroscopy, and SQUID measurement, in conjunction with DFT calculation. The singlet‐triplet energy gap of the donor‐acceptor molecule is dramatically reduced from −18.8 to −7.2 kcal/mol by the coordination with B(C6F5)3 (BCF), which enables an intramolecular single electron transfer from one germylene moiety to another upon heating, forming an intramolecular radical ion pair with diradical character. The work provides an approach to the formation of thermally populated open‐shell species of heavier main group elements. [ABSTRACT FROM AUTHOR]

The synthesis of diradical organic compounds has garnered significant attention due to their thermally accessible spin inversion and optoelectronic properties. Yet, preparing such stable structures with high open‐shell behavior remains challenging. Herein, we report the synthesis and properties of four π‐extended, fused fluorene derivatives with high diradical character, taking advantage of a molecular design where the closed‐shell does not include any Clar sextet, comparatively to a maximum of 5 in the corresponding open‐shell state. This led to an unusual open‐shell triplet ground state with an outstanding singlet‐triplet energy difference (ΔEST) of ca. 19 kcal/mol, one of the highest values reported to date for an all‐carbon conjugated scaffold. Incorporation of dithiafulvene units at each end of the molecule (at the five‐membered rings) furnishes extended tetrathiafulvalenes (TTFs) undergoing reversible oxidations to the radical cation and diradical dication. The various pro‐aromatic structures presented herein show highly localized spin density and a limited conjugation due to the confined π‐electrons in the aromatic cycles, as supported by 1H NMR, UV/Visible, EPR spectroscopy and DFT calculations. [ABSTRACT FROM AUTHOR]

Organoboron compounds are widely utilized in organic synthesis for their diverse reactivity, modular preparation, and stability compared to other classes of organometallic reagents. While organoboron species are commonly employed as nucleophiles in cross‐coupling reactions, their potential as racemic building blocks in enantioconvergent transformations remains largely untapped. Herein, we demonstrate the direct utilization of alkylboronic pinacol esters in intermolecular enantioconvergent transformations. Specifically, this work describes the development and mechanistic study of an enantioconvergent deborylative cyanation enabled by Cu catalysis. This method imparts a high degree of enantioselectivity and tolerates a wide range of common functional groups and heterocycles. The reaction is proposed to proceed through a radical‐relay mechanism. Aniline‐assisted homolysis of the carbon–boron bond results in prochiral alkyl radicals that are functionalized by in situ generated Cu(II)(CN)2 species in an enantioselective fashion. The Cu(II)(CN)2 intermediate was characterized by electron paramagnetic resonance (EPR) spectroscopy, and its electronic structure was probed using density functional theory (DFT) calculations. Computational studies were carried out to corroborate the proposed radical‐relay mechanism. [ABSTRACT FROM AUTHOR]

Copper‐exchanged zeolite omega (Cu‐omega) is a potent material for the selective conversion of methane‐to‐methanol (MtM) via the oxygen looping approach. However, its performance exhibits substantial variation depending on the operational conditions. Under an isothermal temperature regime, Cu‐omega demonstrates subdued activity below 230 °C, but experiences a remarkable increase in activity at 290 °C. Applying a high‐temperature activation protocol at 450 °C causes a rapid deactivation of the material. This behavioral divergence is investigated by combining reactivity studies, neutron diffraction and in situ high‐resolution anomalous X‐ray powder diffraction (HR‐AXRPD), as well as electron paramagnetic resonance spectroscopy, to reveal that the migration of Cu throughout the framework is the primary cause of these behaviors, which in turn is predominantly governed by the degree of hydration of the system. This work suggests that control over the Cu migration throughout the zeolite framework may be harnessed to significantly increase the activity of Cu‐omega by generating more active sites for the MtM conversion. These results underscore the power of in situ HR‐AXRPD for unraveling the behavior of materials under reaction conditions and suggest that a re‐evaluation of Cu‐zeolites priorly deemed inactive for the MtM conversion across a broader range of conditions and looping protocols may be warranted. [ABSTRACT FROM AUTHOR]

Riboswitches control gene regulation upon external stimuli such as environmental factors or ligand binding. The fluoride sensing riboswitch from Thermotoga petrophila is a complex regulatory RNA proposed to be involved in resistance to F− cytotoxicity. The details of structure and dynamics underpinning the regulatory mechanism are currently debated. Here we demonstrate that a combination of pulsed electron paramagnetic resonance (ESR/EPR) spectroscopies, detecting distances in the angstrom to nanometre range, can probe distinct regions of conformational flexibility in this riboswitch. PELDOR (pulsed electron‐electron double resonance) revealed a similar preorganisation of the sensing domain in three forms, i.e. the free aptamer, the Mg2+‐bound apo, and the F−‐bound holo form. 19F ENDOR (electron‐nuclear double resonance) was used to investigate the active site structure of the F−‐bound holo form. Distance distributions without a priori structural information were compared with in silico modelling of spin label conformations based on the crystal structure. While PELDOR, probing the periphery of the RNA fold, revealed conformational flexibility of the RNA backbone, ENDOR indicated low structural heterogeneity at the ligand binding site. Overall, the combination of PELDOR and ENDOR with sub‐angstrom precision gave insight into structural organisation and flexibility of a riboswitch, not easily attainable by other biophysical techniques. [ABSTRACT FROM AUTHOR]

Bacterial microcompartments (BMCs) are prokaryotic organelles that consist of a protein shell which sequesters metabolic reactions in its interior. While most of the substrates and products are relatively small and can permeate the shell, many of the encapsulated enzymes require cofactors that must be regenerated inside. We have analyzed the occurrence of an enzyme previously assigned as a cobalamin (vitamin B12) reductase and, curiously, found it in many unrelated BMC types that do not employ B12 cofactors. We propose Nicotinamide adenine dinucleotide (NAD+) regeneration as the function of this enzyme and name it Metabolosome Nicotinamide Adenine Dinucleotide Hydrogen (NADH) dehydrogenase (MNdh). Its partner shell protein BMC-TSE (tandem domain BMC shell protein of the single layer type for electron transfer) assists in passing the generated electrons to the outside. We support this hypothesis with bioinformatic analysis, functional assays, Electron Paramagnetic Resonance spectroscopy, protein voltammetry, and structural modeling verified with X-ray footprinting. This finding represents a paradigm for the BMC field, identifying a new, widely occurring route for cofactor recycling and a new function for the shell as separating redox environments. [ABSTRACT FROM AUTHOR]

We present, for the first time, an efficient ligand‐free iron‐copper catalyzed cross‐coupling reaction involving a variety of aryl, heteroaryl halides (including chlorides, bromides, and iodides), and alkyl bromides with diverse aryl and aliphatic primary amides, conducted under solvent‐minimized conditions. This economically competitive protocol successfully yielded the corresponding cross‐coupling products, N‐arylamides and N‐alkylamides, in good to excellent yields with broad substrate scope (65 examples) and tolerance to several sensitive functionalities (including heterocycles). No conventional work‐up is required for this protocol, and the developed method is applicable for gram‐scale synthesis. Notably, the catalyst is inexpensive, environmentally friendly, and can be reused at least four times with minimal loss of catalytic activity. A series of experiments, including X‐ray photoelectron spectroscopy (XPS), UV spectroscopy, cyclic voltammetry (CV), electron paramagnetic resonance (EPR), and X‐ray diffraction (XRD) were conducted to identify the oxidation state of active catalytic species and radical clock experiment was performed using a radical probe to investigate the reaction mechanism. Furthermore, we evaluated the antibacterial and anticancer properties of selected synthesized products (3 ii, 3 xii, and 3 xxxx) in‐vitro. The results indicated that the prepared compounds exhibited promising antibacterial and anticancer activities (MTT and Molecular Docking). [ABSTRACT FROM AUTHOR]

Coordination complexes of general formula trans‐[MX2(R2ECH2CH2ER2)2] (MII=Ti, V, Cr, Mn; E=N or P; R=alkyl or aryl) are a cornerstone of coordination and organometallic chemistry. We investigate the electronic properties of two such complexes, trans‐[VCl2(tmeda)2] and trans‐[VCl2(dmpe)2], which thus represent trans‐[MX2(R2ECH2CH2ER2)2] where M=V, X=Cl, R=Me and E=N (tmeda) and P (dmpe). These VII complexes have S=3/2 ground states, as expected for octahedral d3. Their tetragonal distortion leads to zero‐field splitting (zfs) that is modest in magnitude (D≈0.3 cm−1) relative to analogous S=1 TiII and CrII complexes. This parameter was determined from conventional EPR spectroscopy, but more effectively from high‐frequency and ‐field EPR (HFEPR) that determined the sign of D as negative for the diamine complex, but positive for the diphosphine, which information had not been known for any trans‐[VX2(R2ECH2CH2ER2)2] systems. The ligand‐field parameters of trans‐[VCl2(tmeda)2] and trans‐[VCl2(dmpe)2] are obtained using both classical theory and ab initio quantum chemical theory. The results shed light not only on the electronic structure of VII in this environment, but also on differences between N and P donor ligands, a key comparison in coordination chemistry. [ABSTRACT FROM AUTHOR]

Investigation of a published route to produce 3,5-di-tert-butylphenol, starting from commercial 3,5-di-tert-butylbenzoic acid via 3,5-di-tert-butylanlinium hydrogen sulfate, unexpectedly yielded 2,6-dintitro-3,5-di-tert-butylphenol. Attempts to increase the yield of the latter resulted, instead, in the previously unreported 2,6-dinitro-3,5-di-tert-butylcyclohexa-2,5-dien-1,4-dione. Single-crystal X-ray diffraction structures are reported for the anilinium salt, the nitrated phenol, and the quinone. Voltammetry of the quinone shows two chemically reversible reductions in anhydrous solution and the radical anion produced from the first reduction step has been characterized by electron paramagnetic resonance spectroscopy. This compound fits well to the middle range of electron-poor quinones, indicating that the inductive effects of the tert-butyl and nitro groups counteract each other. This conclusion is also supported by the infrared spectroscopic data where the ν(C=O) and ν(C=C) bands are of very similar energy to those of 2,3,5,6-tetrachloro-1,4-benzoquinone. [ABSTRACT FROM AUTHOR]

The rise of atmospheric oxygen as a result of photosynthesis in cyanobacteria and chloroplasts has transformed most environmental iron into the ferric state. In contrast, cells within organisms maintain a reducing internal milieu and utilize predominantly ferrous iron. Ferric reductases are enzymes that transfer electrons to ferric ions, either extracellularly or within endocytic vesicles, enabling cellular ferrous iron uptake through Divalent Metal Transporter 1. In mammals, duodenal cytochrome b is a ferric reductase of the intestinal epithelium, but how insects reduce and absorb dietary iron remains unknown. Here we provide indirect evidence of extracellular ferric reductase activity in a small subset of Drosophila melanogaster intestinal epithelial cells, positioned at the neck of the midgut's anterior region. Dietary-supplemented bathophenanthroline sulphate (BPS) captures locally generated ferrous iron and precipitates into pink granules, whose chemical identity was probed combining in situ X-ray absorption near edge structure and electron paramagnetic resonance spectroscopies. An increased presence of manganese ions upon BPS feeding was also found. Control animals were fed with ferric ammonium citrate, which is accumulated into ferritin iron in distinct intestinal subregions suggesting iron trafficking between different cells inside the animal. Spectroscopic signals from the biological samples were compared to purified Drosophila and horse spleen ferritin and to chemically synthesized BPS-iron and BPS-manganese complexes. The results corroborated the presence of BPS-iron in a newly identified ferric iron reductase region of the intestine, which we propose constitutes the major site of iron absorption in this organism. [ABSTRACT FROM AUTHOR]

New chamber stapes prosthesis (ChSP) is a middle-ear prosthesis intended for use in ear surgery for restoring the patient's middle ear function. As the prosthesis is an implantable medical device, it must be sterilized before use. However, possible alterations in the material and the functional properties following the sterilization process can influence the safety aspects while using the prosthesis. The purpose of this paper was to determine the effects of ionizing radiation (IR) on the physicochemical and biological properties of the new chamber prosthesis by utilizing EPR spectroscopy, mechanical testing, and cytotoxicity studies. Our research shows that the radiation treatment increases the hardness and the elastic modulus of the polymer, decreases the stiffness of the prosthesis membrane, and does not cause chemical changes in the polymers that may result in cytotoxicity. Furthermore, new ChSPs were successfully tested in preclinical in vitro tests. The test results justify the undertaking of further work, including in vivo biocompatibility tests and clinical trials, which would eventually lead to the increased use of the prosthesis in clinical practice. [ABSTRACT FROM AUTHOR]