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Oxalyldihydrazide (ODH) and coffee extracted fuel (CEF) were used to synthesize Ceria (CeO 2) nanoparticles by solution combustion synthesis route. The cubic fluorite structure, crystalline nature, crystallite size and particle size of ceria nanoparticles were confirmed using the powder X-ray diffraction (PXRD) and High-Resolution Transmission Electron Microscope patterns respectively. Field Emission Scanning Electron Microscope (FESEM) images were used to understand the Surface morphology of the synthesized samples. Based on XRD results the volume of coffee husk extract for the optimum phase formation is found to be 40 mL. The fluorite structure of the samples and the presence of oxygen vacancies in the samples were confirmed from the Raman spectral analysis. ESR (Electron Spin Resonance) studies confirmed formation of relatively more intrinsic defects in CEF-ceria nanoparticles compared to ODH-ceria nanoparticles. The semiconducting nature of the synthesized samples was confirmed by analysing UV–visible absorbance spectra. The functional group confirmation was obtained by analysing Fourier Transform Infrared (FTIR) spectra of both the samples. AC conductivity and dielectric relaxation studies of the samples in pellet form were carried out over a wide frequency (20Hz–10 MHz) and temperature (200–640 °C) range using a precision impedance analyser. A higher value of dielectric constant was observed for CEF-ceria nanoparticles. [ABSTRACT FROM AUTHOR]

This work extends the thermodynamic model of associated solutions used in the past to describe the structure and properties of glasses to the area of complex multicomponent glasses with polyvalent elements, where it has not been applied until now either due to the absence of Gibbs energies of formation of the necessary compounds or due to oxidation–reduction equilibrium in the presence of a gas phase containing oxygen. While the fitting of unknown Gibbs energies based on experimental data has already been applied to some extent in our previous work, the implementation of redox is, to the best of our knowledge, new. Four concentration series were taken from the published data from the glass-forming ternary system CaO–MoO3−P2O5: A) xMoO3−(0.5–0.75x)CaO−(0.5–0.25x)P2O5; B) xMoO3−(0.5–0.875x)CaO−(0.5–0.125x)P2O5; C) xMoO3−(0.5−x)CaO−0.5P2O5; M) xMoO3−(1−x)P2O, for which the distributions of Qn units were also published (Q denotes the PO4 tetrahedral unit with n bridging oxygens) by the 31P MAS NMR method and the Mo[V]/ΣMo fraction by the ESR method [Černošek et al. (J Solid State Chem 303:122522, 2021); Holubová et al., (J Non-Cryst Solids 607:122222, 2023)]. The following compounds were considered in the TD model: P2O5, CaO, Mo[VI]O3, Ca(PO3)2, Ca2P2O7, (Mo[VI]O2)(PO3)2, (Mo[VI]O2)2(P2O7), (Mo[VI]O2)3(PO4)2, (Mo[V]O)2(PO3)2(P2O7), (Mo[V]O)PO4. All except the hypothetical compound (Mo[VI]O2)3(PO4)2 exist, and their structure is known. Binary phosphate compounds with molybdenum lack Gibbs energies of formation. Therefore, one of the series, namely A, was used to determine these energies by nonlinear regression with the help of a genetic algorithm, without/with redox, and then the distribution of Qn units and the fraction of Mo[V]/ΣMo was predicted for the remaining series. It was found that the distribution of Qn units can be described by the TD model with redox only. During the reduction of molybdenum, the distribution of Qn unit's changes, and thus also the connectivity of the phosphate network, for example, according to the reactions: (MoO2)2(P2O7)—> 2(MoO)PO4 + 1/2O2, in which Q1—> Q0 and 2(MoO2)(PO3)2—> (MoO)2(PO3)2(P2O7) + 1/2O2 in which Q2—> Q1. Despite the fact that the TD model with redox gives excellent agreement in the case of the Qn distribution, the agreement with the ESR measurements of the Mo[V]/ΣMo ratio is not good. The TD model predicts significantly more pentavalent molybdenum in the glass. [ABSTRACT FROM AUTHOR]

The exhaustion of conventional light oils necessitates the shift towards unconventional sources such as biomass, heavy oil, oil shale, and coal. Non-catalytic thermal cracking by a free radical mechanism is at the heart of the upgrading, prior to refining into valuable products. However, thermal pyrolysis is hindered by the formation of asphaltenes, precursors to coke, limiting cracking, causing equipment fouling, and reducing product stability. Free radicals are inherently present in heavy fractions and are generated during thermal processes. This makes these reactive intermediates central to understanding these mechanisms and limiting coking. Electron spin resonance (ESR) spectroscopy facilitates such mechanistic studies. Over the past decade, there has been no review of using in-situ ESR for studying thermal processes. This work begins with a brief description of free radicals' chain reactions during thermal reactions and the wealth of information ESR provides. We then critically review the literature that uses ESR for mechanistic studies in thermal pyrolysis of biomass, heavy oil, shales, and coal. We conclude that limited literature exist, and more investigations are necessary. The key findings from existing literature are summarized to know the current state of knowledge. We also explicitly highlight the research gaps. [ABSTRACT FROM AUTHOR]

ABSTRACT Characterising the spatial and temporal distribution of the S‐N‐trending rift in southern Tibet is crucial for elucidating the dynamics of E‐W extension within the Tibetan Plateau since the Miocene. The Kung Co–Tangra Yumco rift, located in the central part of the rift system, was initiated at the peak of rifting development. While the initiation of rifting has been ascertained through low‐temperature thermochronology, direct timing constraints remain absent for the Gangga Graben in the southernmost region. Utilising the quartz electron spin resonance (ESR) dating technique, we ascertained the onset age of the eastern boundary fault of the Gangga Graben to be 12.00 ± 1.80 Ma, with an accelerated activity phase at 9.17 ± 1.19 Ma, and an activity age for the western boundary fault at 2.22 ± 0.24 Ma. U‐series dating conducted on the western boundary disclosed a time span of 20–13 ka for hot spring fissure activity. Seismic evidence, inclusive of those from the Gongdapu Horst, indicates persistent activity of the Gangga Graben since the Pleistocene. Comparative analysis of age data from the Kung Co–Tangra Yumco rift suggests that it commenced almost synchronously along its strike at ~14.5–12 Ma. Considering the rifts trending from west to east in southern Tibet and the genetic mechanism of leucogranite, we propose an E‐W extension mechanism in southern Tibet. At ~26–14 Ma, the lithosphere experienced weakened delamination and asthenosphere upwelling, leading to a series of magmatic activities and onset of E‐W extension in southern Tibet. At ~17–7 Ma, as the basal shearing of the underthrusting Indian Plate increased, it marked the peak phase of rifting in southern Tibet. [ABSTRACT FROM AUTHOR]

Skin exposed to ultraviolet light produces hydrogen peroxide (H2O2) and reactive oxygen species (ROS) that cause protein denaturation and other disorders. We investigated whether electrolyticreduction ion water (ERI), which has reducing properties and has been reported to protect skin, exhibits antioxidant activity in skin keratinocytes. The antioxidant activity of ERI was first examined using DPPH assay and Electron Spin Resonance to test for radicals, and using the Amplex Red method to test for H2O2. Concentration-dependent scavenging of hydroxyl radical but no H2O2 depletion were detected. An investigation of the expression of heme oxygenase-1, which is upregulated by oxidative response in cells, showed an increase through H2O2 oxidation, which was inhibited by ERI in a concentration-dependent manner. This suggests that ERI directly removes ROS. Quantitative real-time polymerase chain reaction analysis was performed to determine whether ERI regulates the expression of aquaporin 3 (AQP3), a known H2O2 transporter. This analysis revealed that ERI enhances AQP3 expression in a concentration-dependent manner and is involved in the transport of intracellular H2O2 to the extracellular space. In addition, ERI inhibited H2O2-induced cytotoxicity in a concentration-dependent manner. These results suggest that ERI protects keratinocytes from ROS by directly scavenging them and indirectly by eliminating them through the promotion of the efflux of intracellular H2O2. [ABSTRACT FROM AUTHOR]

Abstract The emergence of the Middle Palaeolithic, and its variability over time and space are key questions in the field of prehistoric archaeology. Many sites have been documented in the south-eastern margins of the Massif central and the middle Rhône valley, a migration path that connects Northern Europe with the Mediterranean. Well-dated, long stratigraphic sequences are essential to understand Neanderthals dynamics and demise, and potential interactions with Homo sapiens in the area, such as the one displayed at the Maras rock shelter (“Abri du Maras”). The site is characterised by exceptional preservation of archaeological remains, including bones dated using radiocarbon (14C) and teeth using electron spin resonance combined with uranium series (ESR/U-series). Optically stimulated luminescence was used to date the sedimentary deposits. By combining the new ages with previous ones using Bayesian modelling, we are able to clarify the occupation time over a period spanning 200,000 years. Between ca. 250 and 40 ka, the site has been used as a long-term residence by Neanderthals, specifically during three interglacial periods: first during marine isotopic stage (MIS) 7, between 247 ± 34 and 223 ± 33 ka, and then recurrently during MIS 5 (between 127 ± 17 and 90 ± 9 ka) and MIS 3 (up to 39,280 cal BP).

The emergence of the Middle Palaeolithic, and its variability over time and space are key questions in the field of prehistoric archaeology. Many sites have been documented in the south-eastern margins of the Massif central and the middle Rhône valley, a migration path that connects Northern Europe with the Mediterranean. Well-dated, long stratigraphic sequences are essential to understand Neanderthals dynamics and demise, and potential interactions with Homo sapiens in the area, such as the one displayed at the Maras rock shelter ("Abri du Maras"). The site is characterised by exceptional preservation of archaeological remains, including bones dated using radiocarbon (14C) and teeth using electron spin resonance combined with uranium series (ESR/U-series). Optically stimulated luminescence was used to date the sedimentary deposits. By combining the new ages with previous ones using Bayesian modelling, we are able to clarify the occupation time over a period spanning 200,000 years. Between ca. 250 and 40 ka, the site has been used as a long-term residence by Neanderthals, specifically during three interglacial periods: first during marine isotopic stage (MIS) 7, between 247 ± 34 and 223 ± 33 ka, and then recurrently during MIS 5 (between 127 ± 17 and 90 ± 9 ka) and MIS 3 (up to 39,280 cal BP). [ABSTRACT FROM AUTHOR]

The Murun massif (Aldan shield, Russia) is particularly intriguing due to its group of alkali Ca-(K)-(Na) silicates, which includes many new and rare species. Additionally, it is also of interest for its beryllium mineralization. One of the unique beryllium Ca-(K)-(Na) silicates, odintsovite K2Na4Ca3Ti2Be4Si12O38, was investigated in this study. The aim of this study is to provide new insights into the crystal chemistry and spectroscopic properties of odintsovite. DFT modelling was used to interpret the experimental IR and Raman spectra. Determining the crystal-chemical formula of odintsovite is challenging due to the presence of atoms in different structural positions with varying valence states. The distribution of cations was determined by combining electron probe microanalysis with the results of crystal structure refinement. Luminescence of Eu3+ was observed in odintsovite upon excitation at around 532 nm. Analysis of the luminescence band splitting is related to the 4f–4f transitions in Eu3+ ions. Additionally, upon excitation at around 370 nm, luminescence with a peak at around 410 nm, associated with 5d–4f transitions in Ce3+ ions, was observed. [ABSTRACT FROM AUTHOR]

Li3V2(PO4)3-based composites as a lithium-ion battery cathode material were synthesized by the hydrothermal method with subsequent annealing in an Ar atmosphere. The as-prepared samples were characterized by X-ray diffraction analysis and electron spin resonance (ESR) methods. Based on ESR, data the quantitative estimation of V4+ content was performed. The tetravalent vanadium ions arised instead of trivalent vanadium ions due to lithium nonstoichiometry in Li3V2(PO4)3 structure. This method of identifying nonstoichiometry via ESR detection of V4+ ions is very simple and demonstrative and can be used to characterize not only as-prepared samples but also samples after multiple electrochemical cycling. This technique of the lithium nonstoichiometry detection in Li3V2(PO4)3 can be used if the valence state of vanadium ions is stable and investigated samples are not degraded during a long time. To clarify the question, the additional ESR measurements were performed for Li3V2(PO4)3 samples which were air-stored over a long period (up to 2 years). The obtained data proved the sample degradation in the form of increasing in V4+ content. It was found that in the presence of LiPO3 salt in the composite the number of magnetic centers increased significantly, so it contributed to sample degradation, while the pure Li3V2(PO4)3 sample Li3V2(PO4)3/C were most stable. [ABSTRACT FROM AUTHOR]

The authors study the formation of crystals of Fe-Ga oxides and Fe–Ga–Cu borates in a multicomponent flux system based on Bi2Mo3O12–Na2B4O7. The Curie–Weiss temperature (θCW = 289 K) and the temperature of the ferrimagnet–paramagnet phase transition (TC = 288 K) are determined from the electron spin resonance (ESR) spectrum and the magnetization of an Fe1.1Ga0.9O3 single crystal, depending on temperature. Lines of spin-wave resonance are observed in the spectrum of magnetic resonance in the ordered phase. [ABSTRACT FROM AUTHOR]

The effect of storage time and solvent on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical stability was studied using electron spin resonance. Tetrahydrofuran affected the g-factor due to a rearrangement within the DPPH structure that changed the radical centre. There was also a change in the spins concentration when modifying the solvent and storage times. The more than 96 % decrease in spins after 12 weeks, consistent with a change in the pH and color, was attributed to the electron- and hydrogen-donor capabilities of the solvents, leading to a shift among the different DPPH ionic states. Tetralin instantly interacted with the DPPH capping many radicals.

Abstract The Periadriatic Fault system (PAF) ranks among the largest post-collisional structures of the European Alps. Recent geodetic data suggest that a fraction of the Adria–Europe convergence is still being accommodated in the Eastern Alps. However, the historical seismicity records along the easternmost segment of the PAF are ambiguous, and instrumental records indicate that seismotectonic deformation is mostly concentrated in the adjacent Southern Alps and Dinarides. Both electron spin resonance (ESR) and optically stimulated luminescence (OSL) dating methods can be used to date coseismic slip (with a combined range covering a few decades to a couple of million years) in slowly deforming fault zones, such as the PAF. Since the saturation doses of the quartz ESR signals are larger than quartz and feldspar OSL, ESR enables establishing a maximum age of the last resetting event of the system, while OSL allows constraining their minimum age when the signal is in saturation. We collected fault gouge samples from three localities along the easternmost segment of the PAF. For ESR, we measured the signals from the Al center in quartz comparing the results from the single aliquot additive dose (SAAD) and single aliquot regenerative (SAR) dose protocols. For OSL, we recorded the infrared stimulated luminescence signal at 50°C (IR50) and post-infrared infrared-stimulated luminescence signal at 225 °C (pIRIR225). Our dating results indicate that the studied segment of the PAF system accommodated seismotectonic deformation during the Quaternary, with a maximum age for the last resetting event of the system ranging from 1075 ± 48 to 552 ± 26 ka (ESR SAR) and minimum ages in the range from 196 ± 12 to 281 ± 16 ka (saturation of pIRIR225). The obtained ages suggest that the studied segment of the PAF could be considered at least as a potentially active fault. Graphical abstract

We investigated the temperature dependence of agglomeration systems consisting of interacting single-domain magnetic nanoparticles (MNPs). In our study, we utilized electron spin resonance (ESR) experiments to measure how temperature-induced change in agglomerate state affects the peak-to-peak width of ESR spectra (Hpp) and validated these observations through simulations. Micromagnetic simulations were conducted by combining the classical magnetic dipolar Metropolis Monte Carlo method with the semi-classical macro-spin Landau-Lifshitz-Gilbert finite element method, and the results were compared with experimental findings. Our research elucidates the behavior of thermally-induced disruption of MNP agglomerates. We discovered that the temperature at which MNPs are completely dispersed might correspond to one at which the temperature dependence of Hpp disappears.

The Periadriatic Fault system (PAF) ranks among the largest post-collisional structures of the European Alps. Recent geodetic data suggest that a fraction of the Adria–Europe convergence is still being accommodated in the Eastern Alps. However, the historical seismicity records along the easternmost segment of the PAF are ambiguous, and instrumental records indicate that seismotectonic deformation is mostly concentrated in the adjacent Southern Alps and Dinarides. Both electron spin resonance (ESR) and optically stimulated luminescence (OSL) dating methods can be used to date coseismic slip (with a combined range covering a few decades to a couple of million years) in slowly deforming fault zones, such as the PAF. Since the saturation doses of the quartz ESR signals are larger than quartz and feldspar OSL, ESR enables establishing a maximum age of the last resetting event of the system, while OSL allows constraining their minimum age when the signal is in saturation. We collected fault gouge samples from three localities along the easternmost segment of the PAF. For ESR, we measured the signals from the Al center in quartz comparing the results from the single aliquot additive dose (SAAD) and single aliquot regenerative (SAR) dose protocols. For OSL, we recorded the infrared stimulated luminescence signal at 50°C (IR50) and post-infrared infrared-stimulated luminescence signal at 225 °C (pIRIR225). Our dating results indicate that the studied segment of the PAF system accommodated seismotectonic deformation during the Quaternary, with a maximum age for the last resetting event of the system ranging from 1075 ± 48 to 552 ± 26 ka (ESR SAR) and minimum ages in the range from 196 ± 12 to 281 ± 16 ka (saturation of pIRIR225). The obtained ages suggest that the studied segment of the PAF could be considered at least as a potentially active fault. [ABSTRACT FROM AUTHOR]

The crystal structures of three mixed‐valence copper cyanide alkanolamine polymers are presented, together with thermogravimetric analysis (TGA) and electron spin resonance (ESR) data. In all three structures, a CuII moiety on a crystallographic center of symmetry is coordinated by two alkanolamines and links two CuICN chains via cyanide bridging groups to form diperiodic sheets. The sheets are linked together by cuprophilic CuI–CuI interactions to form a three‐dimensional network. In poly[bis(μ‐3‐aminopropanolato)tetra‐μ‐cyanido‐dicopper(I)dicopper(II)], [Cu4(CN)4(C3H8NO)2]n, 1, propanolamine bases have lost their hydroxyl H atoms and coordinate as chelates to two CuII atoms to form a dimeric CuII moiety bridged by the O atoms of the bases with CuII atoms in square‐planar coordination. The ESR spectrum is very broad, indicating exchange between the two CuII centers. In poly[bis(2‐aminopropanol)tetra‐μ‐cyanido‐dicopper(I)copper(II)], [Cu3(CN)4(C3H9NO)2]n, 2, and poly[bis(2‐aminoethanol)tetra‐μ‐cyanido‐dicopper(I)copper(II)], [Cu3(CN)4(CH7NO)2]n, 3, a single CuII atom links the CuICN chains together via CN bridges. The chelating alkanolamines are not ionized, and the OH groups form rather long bonds in the axial positions of the octahedrally coordinated CuII atoms. The coordination geometries of CuII in 2 and 3 are almost identical, except that the Cu—O distances are longer in 2 than in 3, which may explain their somewhat different ESR spectra. Thermal decomposition in 2 and 3, but not in 1, begins with the loss of HCN(g), and this can be correlated with the presence of OH protons on the ligands in 2 and 3, which are not present in 1. [ABSTRACT FROM AUTHOR]

We studied the electron spin resonance (ESR) spectra of nitrogen atoms stabilized in nitrogen-neon nanoclusters immersed in superfluid 4 He. The nanoclusters were formed during the condensation of the products of the discharge in N 2 –Ne–He gas mixtures into bulk superfluid 4 He at temperature 1.5 K. We studied nanoclusters formed by injection of gas mixtures with different ratios of heavy impurities in the helium N 2 /(Ne + N 2 ) ranging from 2% to 90%. Analysis of the ESR spectra of nitrogen atoms stabilized in nitrogen-neon nanoclusters provides important information about the environment of the stabilized atoms and a shell structure of the nanoclusters was revealed. For all samples studied, preferential stabilization of N atoms on the surfaces of the nanoclusters was observed. Annealing of the collection of the nanoclusters in the temperature range 1.1–10 K resulted in substantial changes in the structure of the nanoclusters. [ABSTRACT FROM AUTHOR]

We report on electron spin resonance studies of H atoms stabilized in solid H 2 films at temperature 0.7 K and in a magnetic field of 4.6 T. The H atoms were produced by bombarding H 2 films with 100 eV electrons from a radiofrequency discharge run in the sample cell. We observed a one order of magnitude faster H atom accumulation in the films made of para-H 2 gas with a small ortho-H 2 concentration (0.2% ortho-H 2 ) as compared with those made from normal H 2 gas content (75% ortho-H 2 ). We also studied the influence of ortho-H 2 molecules on spatial diffusion of H atoms in solid H 2 films. The spatial diffusion of H atoms in both normal and para-H 2 films is faster than the diffusion obtained from the measurement of H atom recombination. The rate of spatial diffusion of H atoms in para-H 2 films was slower in comparison with that in the normal H 2 films. We discuss possible explanations of these observations. [ABSTRACT FROM AUTHOR]

Glass-nanocomposites (GNCs) samples of composition [(100−x) Li2B4O7–xPbTiO3] with x = 5, 10, 15 and 20 mol% were prepared by melt quenching method. The two phases of the GNCs samples, a glassy phase and PbTiO3 nanoparticles/clusters phase, can be seen in the energy dispersive X-ray spectra and scanning electron microscopic micrographs. Fourier transformation infrared spectra of the GNCs samples exhibited bands due to triangular with NBO's and tetrahedral borate groups. Additionally, the Ti4+ ions exist in both TiO4 and TiO6 structural units while the Ti3+ ions exist in TiO6 structural units. The electron spin resonance (ESR) spectra of the GNCs samples exhibit two ESR signals, broad and narrow, corresponding to the Ti3+ (3d1) ions in both tetragonal deformed octahedral and in the other structural configuration, respectively. The optical transmission spectra of the GNCs samples exhibited three transmission bands, 3Γ5 → 2Γ3, 2B2g → 2B1g and 2B2g → 2A1g transitions, in the visible region. The variation in optical band gap (Eopt) with increasing PbTiO3 content were due to the conversion between BO3 with NBOs and BO4 units as well as the reduction of Ti4+ to Ti3+ ions in the GNCs matrix. These results demonstrate that the present GNCs may be used for practical applications such as optical devices. [ABSTRACT FROM AUTHOR]

We investigated the temperature dependence of agglomeration systems consisting of interacting single-domain magnetic nanoparticles (MNPs). In our study, we utilized electron spin resonance (ESR) experiments to measure how temperature-induced change in agglomerate state affects the peak-to-peak width of ESR spectra (H pp) and validated these observations through simulations. Micromagnetic simulations were conducted by combining the classical magnetic dipolar Metropolis Monte Carlo method with the semi-classical macro-spin Landau-Lifshitz-Gilbert finite element method, and the results were compared with experimental findings. Our research elucidates the behavior of thermally-induced disruption of MNP agglomerates. We discovered that the temperature at which MNPs are completely dispersed might correspond to one at which the temperature dependence of H pp disappears. [ABSTRACT FROM AUTHOR]

The electron spin resonance‐based photosafety test (ESR‐PT) was modified using a new parameter, photoreactivity index (PRI), to detect singlet oxygen and free radical photoproducts simultaneously. With this modification, the modified ESR‐PT is expected to reduce the number of false negative results due to chemicals producing free radical photoproducts other than singlet oxygen. The assay performance of the modified ESR‐PT was evaluated using 56 chemicals, including hydrophobic chemicals. When using the PRI cutoff value of 2.0 in the modified ESR‐PT, the accuracy relative to photosafety reference data was 91.1%, and the applicability (100%) was better than the other non‐animal photosafety test. Among the chemicals producing positive results, bithionol, fenticlor, and doxycycline HCl were considered positive based on the detection of free radical photoproducts, suggesting that these three chemicals may have phototoxic or photoallergic potential via radical reactions. Additionally, this finding demonstrated the fundamental advantage of the modified ESR‐PT using ESR spectroscopy, which can detect radicals selectively and quantitatively. Accordingly, the new parameter PRI is effective for photosafety evaluations based on not only singlet oxygen but also free radical photoproducts generated from chemicals. Therefore, the modified ESR‐PT has a great potential for a photosafety test method applicable to various chemicals. We established a modified electron spin resonance‐based photosafety test (ESR‐PT), which uses the photoreactivity index (PRI) for simultaneous detection of singlet oxygen and free radical photoproducts generated from chemicals. The assay performance of the modified ESR‐PT was evaluated by testing 56 chemicals, and the accuracy with comparison to the known photosafety reference data was confirmed to be 91.1% using the PRI cutoff value of 2.0. [ABSTRACT FROM AUTHOR]

The output of photovoltaic (PV) devices is mostly independent of the wavelength of the incident light, whereas an anomalous wavelength‐dependent photovoltaic effect (WDPE) has recently been observed in antimony chalcohalide‐chalcogenide (SbSI:Sb2S3) PVs. Remarkably, the open‐circuit voltage (VOC) exhibits a reversible change between low VOC for short wavelengths and high VOC for long wavelengths. Herein, this work presents i) insights into the underlying mechanisms of this phenomenon by electron spin resonance (ESR) measurements and ii) the switchable character of WDPE depending on the hole transport material (HTM). Operando ESR measurements with light irradiation revealed that the hole density in the HTM is significantly suppressed when the ultraviolet component is included in the irradiation light. This indicated interfacial charge recombination rather than hole transfer to the HTM under short‐wavelength light irradiation, providing a basis for understanding the mechanism of WDPE. Furthermore, the use of poly(triarylamine) as the HTM unexpectedly exhibit the opposite wavelength‐VOC dependence, where a low VOC is observed with long‐wavelength light. In addition, the introduction of a polar gas accelerated the response speed of these effects. These findings shed light on the expansion of unique wavelength‐responsive single junction devices. [ABSTRACT FROM AUTHOR]

Li3V2(PO4)3 cathodes for Li-ion batteries (LIBs) were synthesized using a hydrothermal method with the subsequent annealing in an argon atmosphere to achieve optimal properties. The X-ray diffraction analysis confirmed the material's single-phase nature, while the scanning electron microscopy revealed a granular structure, indicating a uniform particle size distribution, beneficial for electrochemical performance. Magnetometry and electron spin resonance studies were conducted to investigate the magnetic properties, confirming the presence of the relatively low concentration and highly uniform distribution of tetravalent vanadium ions (V4+), which indicated low lithium deficiency values in the original structure and a high degree of magnetic homogeneity in the sample, an essential factor for consistent electrochemical behavior. For this pure phase Li3V2(PO4)3 sample, devoid of any impurities such as carbon or salts, extensive electrochemical property testing was performed. These tests resulted in the experimental discovery of a remarkably high lithium diffusion coefficient D = 1.07 × 10−10 cm2/s, indicating excellent ionic conductivity, and demonstrated impressive stability of the material with sustained performance over 1000 charge–discharge cycles. Additionally, relithiated Li3V2(PO4)3 (after multiple electrochemical cycling) samples were investigated using scanning electron microscopy, magnetometry and electron spin resonance methods to determine the extent of degradation. The combination of high lithium diffusion coefficients, a low degradation rate and remarkable cycling stability positions this Li3V2(PO4)3 material as a promising candidate for advanced energy storage applications. [ABSTRACT FROM AUTHOR]

Dehydrogenation of formic acid (FA) via photocatalytic technology is an attractive strategy to meet the enhanced demand of hydrogen. Regarding the existing complex modification strategies and unclear mechanism of visible-light response CdS-based photocatalytic materials for dehydrogenation of FA, a simple surface nickel-modified CdS nanocrystals has been constructed for boosting the hydrogen production from FA. In situ infrared spectroscopy and electron spin resonance technology were utilized to study the entire photocatalytic decomposition process of FA, which have limited study in previous work. The surface nickel-modification promoted the adsorption of formic acid on the material surface and the generation of key intermediate hydroxyl radicals, leading to faster hydrogen production and enhanced stability. Consequently, the photocatalytic activity was 12.8 times higher than that of unmodified CdS materials after 48 h irradiation. This work provides a new approach for constructing simple and efficient visible-light response CdS-based photocatalysts for hydrogen production from FA under mild condition. Surface nickel modification promotes the adsorption of formic acid on the surface of photocatalysts and the generation of key reaction intermediates hydroxyl radicals, in addition to enhancement of photo-response and separation of photogenerated carrier, thereby improving dehydrogenation from formic acid. [Display omitted] • A simple Ni-modification of CdS enhances photocatalytic dehydrogenation of FA. • Ni modification promotes adsorption of FA and favors the dehydrogenation pathway. • Ni modification facilitates the generation of key species hydroxyl radicals. • Ni modification accelerates the consumption of formate. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles are of great interest to scientists as potential drug carriers. Therefore, it is essential to analyze the processes these nanoparticles undergo at the cellular level. The present paper demonstrates the effect of a constant and rotating magnetic field on penetration of TEMPOL-functionalized magnetite nanoparticles into yeast cells. The interactions between nanoparticles and yeast cells without and with a magnetic field were studied using electron spin resonance spectroscopy (ESR). The results showed that the ESR method can monitor the effect of a magnetic field on the magnetite nanoparticle penetration rate into the cells. [ABSTRACT FROM AUTHOR]

An amphotropic liquid crystal polyacetylene derivative with pyrimidine–type two-ringed mesogenic core, exhibiting both thermotropic and lyotropic liquid crystallinity, was synthesized in this study. The polyacetylene derivative showed a lyotropic liquid crystal in d-limonene. The cis configuration of the main chain was confirmed via1H NMR. Heat treatment induced cis–trans isomerization of the as-prepared polymer. Gas-phase iodine doping of the polymer initiated a chemical interaction between the polyene and iodine, acting as an electron acceptor, generating charge carriers (radical cations, solitons) detected with the electron spin resonance spectroscopy. Moreover, gas phase doping of the polymer induced cis–trans isomerization. [ABSTRACT FROM AUTHOR]

A σ-bonded dimer of 4,8,10-trioxotriangulene (TOT) was newly synthesized and its electronic spin structure was characterized. The neutral diradical had a singlet ground state due to the strong antiferromagnetic interaction through the σ-bond. The strong intramolecular interaction within the σ-dimer caused a near-infrared photoabsorption of around 700-1,000 nm, which is close to that of the π-stacked dimer of TOT monoradical. [ABSTRACT FROM AUTHOR]

Abstract Background Eucommia ulmoides (E. ulmoides) leaves are identified as a new resource of medicine and food homology. In this study, the structural characterization, physicochemical properties, and antioxidant activity of E. ulmoides polysaccharides (EUP) were studied. Results Three components with different molecular weights of 1.51 × 105 Da (EUP1), 3.05 × 104 Da (EUP2) and 1.17 × 105 Da (EUP3) were purified from E. ulmoides leaves. They were composed of l -rhamnose (Rha), d -arabinose (Ara), d -mannose (Man), d-glucose (Glu) and d -galactose (Gal), while EUP2 also contained small amounts of d -xylose (Xyl). Three components all had typical polysaccharides absorption peaks, which may be polysaccharides with β configuration of pyranose structure, and amorphous structure of acid polysaccharides with good thermal stability below 270 ℃. However, the molecular weight, monosaccharide composition and apparent morphology of the three components were different, resulting in a stronger scavenging ability of EUP2 and EUP3 against DPPH and OH free radicals. Conclusion The results will provide a theoretical reference for developing EUP-related foods and drugs. Graphical Abstract

Various studies have demonstrated that employing ESR spin trapping to detect free radicals yields valuable insights into the vulnerability of bulk oils to oxidation. Consequently, this method can be employed to assess and compare the oxidative stability of different samples. This study was conducted to investigate the production and transformation of free radicals and trans isomers in linseed oil when subjected to different temperatures and durations of heating. These analyses revealed that the peak levels of free radicals PBN adducts were evident in linseed oil heated to 120 °C, while these levels decreased within 90 min and were absent at a higher temperature of 180 °C. Free radical PBN adducts were readily degraded at 180 °C. Levels of heat-induced trans isomers rose in linseed oil samples with rising temperatures but began to degrade at temperatures exceeding 240 °C partially. The content examination of these trans isomers revealed that the double bonds located at positions 9 and 15 exhibited a higher susceptibility to isomerization compared to the double bond at position 12. Furthermore, the values of k and Ea indicated that the synthesis of tri-trans-α-linolenic acid (TALAs) was more challenging compared to double-TALAs, and double-TALAs were more challenging than single-TALAs. This was because the tri-TALAs has a higher Ea value than the mono-TALAs and double-TALAs. The study has demonstrated that subjecting linseed oil to high-temperature heating leads to the production of free radicals and trans isomers. And PBN radical adduct is unstable at 180 °C and the double bonds at positions 9 and 15 could be isomerized more easily than that at position 12. These results indicated that controlling the formation of free radicals and single-TALAs isomers may be the key way to reduce the trans isomers of linolenic acid during cooking oil heating. In the follow-up study, we found that VE, VK3, ethyl caffeic acid and resveratrol had significant inhibitory effects on the formation of TALAs of linolenic acid, and the highest inhibitory rate of resveratrol with 5% addition could be reached to 30.86%. The above substances can be applied to the thermal processing of linseed oil to prevent the formation of TALAs.

Our previous study showed that nanobubbles (NBs) encapsulating CO2 gas have bactericidal activity due to reactive oxygen species (ROS) (Yamaguchi et al., 2020). Here, we report that bulk NBs encapsulating CO2 can be efficiently generated by ultrasonically irradiating carbonated water using a piezoelectric transducer with a frequency of 1.7 MHz. The generated NBs were less than 100 nm in size and had a lifetime of 500 h. Furthermore, generation of ROS in the NB suspension was investigated using electron spin resonance spectroscopy and fluorescence spectrometry. The main ROS was found to be the hydroxyl radical, which is consistent with our previous observations. The bactericidal activity lasted for at least one week. Furthermore, a mist generated by atomizing the NB suspension with ultrasonic waves was confirmed to have the same bactericidal activity as the suspension itself. We believe that the strong, persistent bactericidal activity and radical generation phenomenon are unique to NBs produced by ultrasonic irradiation of carbonated water. We propose that entrapped CO2 molecules strongly interact with water at the NB interface to weaken the interface, and high-pressure CO2 gas erupts from this weakened interface to generate ROS with bactericidal activity.

Food irradiation aims to eliminate biohazards such as pathogens, microbes, fungi, etc., as the identification of irradiated food and dose assessment ensures its safe use. Hazelnut is the most universal widespread nut and can be found as a whole fruit or as an ingredient in many food types. Electron paramagnetic resonance (EPR) was used to identify irradiated hazelnut and assess radiation doses delivered to it using fractions of its kernel and/or shells. In this paper, parameters affecting the proper detection and evaluation of irradiated hazelnut kernels and shells are studied and analyzed, including the response to Cs-137 gamma rays, the effect of the change in microwave power and modulation amplitude values during EPR spectra acquisition, and the time dependence of the induced radicals. The stability study of the radiation-induced radicals suggests that it is better to perform EPR measurements for irradiated hazelnut during the first month following irradiation. [ABSTRACT FROM AUTHOR]

This study introduces the synthesis of graphite-carbon nitrite (g-C3N4) using thermal treatment of urea. The prepared powder is treated to generate nanoparticles. The structure and grain size of the g-C3N4 have been obtained via X-ray diffraction (XRD) technique and transmission electron microscope. The graphite-carbon nitride on Polyvinyl Chloride (PVC/g-C3N4) nanocomposite films were produced by mixing different concentrations (0, 3, 5, 7, 10 and 20 wt%) of nanoparticles with Polyvinyl Chloride (PVC) solutions. The structure and elemental composition of the prepared nanocomposites films PVC/g-C3N4 were studied by using XRD, scanning electron microscope (SEM), (EDX), infrared spectroscopy (IR) and electron spin resonance (ESR). Also, spectral distribution of the optical absorbance for the PVC/g-C3N4 nanocomposites films was studied in the wavelength range from 190 to 1100 nm. Thermal stability of the investigated nanocomposites films was investigated by thermal gravimetric analysis technique (TGA). The effect of various concentrations of the g-C3N4 and different doses of gamma-rays on the polymeric matrix and electrical properties of PVC film also has been investigated. The g-C3N4 additives on PVC influenced the crystal structure and optical properties of the nanocomposites films. The nanocomposite film with 10% g-C3N4 achieved higher values of the refractive index and optical conductivity compared with the other films. With different doses of gamma-ray irradiation, the crystal structure and optical properties of PVC/g-C3N4 nanocomposite films were changed in accordance to the cross-linking process within the PVC polymeric chains where a structural rearrangement can be occurred as a result of gamma irradiation. The elemental composition and morphological study of PVC/g-C3N4 nanocomposite films have been checked by the scanning electron microscopy which indicated the homogeneous dispersion of g-C3N4 nanoparticles within PVC network. Finally, electrical properties of PVC/g-C3N4 nanocomposite films with different ratios and distinct gamma doses also have been studied. [ABSTRACT FROM AUTHOR]

Frustration in magnetic materials arising from competing exchange interactions can prevent the system from adopting long-range magnetic order and can instead lead to a diverse range of novel quantum and topological states with exotic quasiparticle excitations. Here, we review prominent examples of such states, including magnetically-disordered and extensively degenerate spin ices with emergent magnetic monopole excitations, highly-entangled quantum spin liquids with fractional spinon excitations, topological order, and emergent gauge fields, as well as complex particle-like topological spin textures known as skyrmions. We provide an overview of recent advances in the search for magnetically-disordered candidate materials on the three-dimensional pyrochlore lattice and two-dimensional triangular, kagome and honeycomb lattices, the latter with bond-dependent Kitaev interactions, and on lattices supporting topological magnetism. We highlight experimental signatures of these often elusive phenomena and single out the most suitable experimental techniques that can be used to detect them. Our review also aims at providing a comprehensive guide for designing and investigating novel frustrated magnetic materials, with the potential of addressing some important open questions in contemporary condensed matter physics. [ABSTRACT FROM AUTHOR]

Highly dispersed Ni‐TiO2 catalyst has been studied in the process of preparation and under catalytic transfer hydrogenation reaction conditions in supercritical 2‐propanol (250°C, 70 bar) using electron spin resonance in situ. Electron spin resonance in situ has been used to study the process of the catalyst passivation and subsequent reduction of the oxide layer in the gas flow. Reduction of the NiO layer on the surface of passivated Ni nanoparticles has been detected in supercritical 2‐propanol, which is in agreement with kinetic modeling data. It has been found that the reduction of the nickel oxide layer in supercritical 2‐propanol occurs at a lower temperature compared with the reduction in hydrogen flow, according to in situ electron spin resonance study. [ABSTRACT FROM AUTHOR]

In this study, we have characterized the acid-pretreated gelatin extracted from duck skin by-products. To this end, we employed two-dimensional gel electrophoresis to validate the size of gelatin (72 kDa) and scanning electron microscopy to examine the surface characteristics of gelatin. We next examined the antioxidant activity of acid-pretreated gelatin extracted from duck skin by three-dimensional imaging using electronic spin resonance. The results show Alkyl, 1,1-diphenyl-2-picrylhydrazyl, and hydroxyl radical scavenging capabilities of acid-pretreated gelatin. We hope that these data will help expand the industrial application of duck-skin-derived gelatin. [ABSTRACT FROM AUTHOR]

The structure and magnetic properties of the single crystal of bis{1-[4-(4-pentyloxybenzoyl-oxy)phenyl]-1-amino-3-pentylprop-1-en-3-onate}copper(II), which shows nematic mesomorphism, were studied by X-ray diffraction and electron spin resonance spectroscopy. [ABSTRACT FROM AUTHOR]

Among the 5d transition metal iridates, Sr2IrO4, which has a layered chalcogenide structure, has received much attention due to its strong spin–orbit coupling (SOC), which produces Mott insulating states and anomalous physical behaviors. In this paper, the microscopic magnetism of Sr2IrO4 is studied with electron spin resonance (ESR) measurements. The Lande factor g of the ferromagnetic resonance signal of Sr2IrO4 shows anomalous behavior compared to typical ferromagnets. It gradually decreases, and the corresponding resonance field Hr increases, with decreasing temperature. The various physical parameters. including the saturated magnetic field Hs derived from M-H, Hr, ΔHpp, the g factor and the intensity I extracted from ESR spectra, are analyzed in detail. Eventually, it is revealed that the anomalous behavior of the g-factor is induced by in-plane Dzyaloshinsky–Moriya interaction (DMI) rather than the SOC effect. [ABSTRACT FROM AUTHOR]

Background: Eucommia ulmoides (E. ulmoides) leaves are identified as a new resource of medicine and food homology. In this study, the structural characterization, physicochemical properties, and antioxidant activity of E. ulmoides polysaccharides (EUP) were studied. Results: Three components with different molecular weights of 1.51 × 105 Da (EUP1), 3.05 × 104 Da (EUP2) and 1.17 × 105 Da (EUP3) were purified from E. ulmoides leaves. They were composed of l-rhamnose (Rha), d-arabinose (Ara), d-mannose (Man), d-glucose (Glu) and d-galactose (Gal), while EUP2 also contained small amounts of d-xylose (Xyl). Three components all had typical polysaccharides absorption peaks, which may be polysaccharides with β configuration of pyranose structure, and amorphous structure of acid polysaccharides with good thermal stability below 270 ℃. However, the molecular weight, monosaccharide composition and apparent morphology of the three components were different, resulting in a stronger scavenging ability of EUP2 and EUP3 against DPPH and OH free radicals. Conclusion: The results will provide a theoretical reference for developing EUP-related foods and drugs. [ABSTRACT FROM AUTHOR]

Block copolymers are a class of materials that are particularly interesting with respect to their capability to self-assemble in ordered structures. In this context, the coupling between environment and dynamics is particularly relevant given that movements at the molecular level influence various properties of macromolecules. Mixing the polymer with a second macromolecule appears to be an easy method for studying these relationships. In this work, we studied blends of poly(methyl methacrylate) (PMMA) and a block copolymer composed of PMMA as the first block and poly(3-methyl-4-[6-(methylacryloyloxy)-hexyloxy]-4′-pentyloxy azobenzene) as the second block. The relaxational properties of these blends were investigated via electron spin resonance (ESR) spectroscopy, which is sensitive to nanometric length scales. The results of the investigations on the blends were related to the dynamic behavior of the copolymers. At the nanoscale, the study revealed the presence of heterogeneities, with slow and fast dynamics available for molecular reorientation, which are further modulated by the ability of the block copolymers to form supramolecular structures. For blends, the heterogeneities at the nanoscale were still detected. However, it was observed that the presence of the PMMA as a major component of the blends modified their dynamic behavior. [ABSTRACT FROM AUTHOR]

In order to create new biodegradable nanocomposites for biomedicine, packaging, and environmentally effective adsorbents, ultra-thin composite fibers consisting of poly(3-hydroxybutyrate) (PHB) and graphene oxide (GO) were obtained by electrospinning. Comprehensive studies of ultrathin fibers combining thermal characteristics, dynamic electron paramagnetic resonance (ESR) probe measurements, and scanning electron microscopy (SEM) were carried out. It is shown that at the addition of 0.05, 0.1, 0.3, and 1% OG, the morphology and geometry of the fibers and their thermal and dynamic characteristics depend on the composite content. The features of the crystalline and amorphous structure of the PHB fibers were investigated by the ESR and DSC methods. For all compositions of PHB/GO, a nonlinear dependence of the correlation time of molecular mobility TEMPO probe (τ) and enthalpy of biopolyether melting (ΔH) is observed. The influence of external factors on the structural-dynamic properties of the composite fiber, such as hydrothermal exposure of samples in aqueous medium at 70 °C and ozonolysis, leads to extreme dependencies of τ and ΔH, which reflect two processes affecting the structure in opposite ways. The plasticizing effect of water leads to thermal destruction of the orientation of the pass-through chains in the amorphous regions of PHB and a subsequent decrease in the crystalline phase, and the aggregation of GO nanoplates into associates, reducing the number of GO-macromolecule contacts, thus increasing segmental mobility, as confirmed by decreasing τ values. The obtained PHB/GO fibrillar composites should find application in the future for the creation of new therapeutic and packaging systems with improved biocompatibility and high-barrier properties. [ABSTRACT FROM AUTHOR]

Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time-dependent changes in melanin-derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20-22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time-dependent decay of melanin-derived radicals. The half-life of eumelanin-derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non-invasive, non-destructive, and highly specific EPR technique.

Coherent control of individual atomic and molecular spins on surfaces has recently been demonstrated by using electron spin resonance (ESR) in a scanning tunneling microscope (STM). Here, a combined experimental and modeling study of the ESR of a single hydrogenated Ti atom that is exchange‐coupled to a Fe adatom positioned 0.6–0.8 nm away by means of atom manipulation is presented. Continuous wave and pulsed ESR of the Ti spin show a Rabi rate with two contributions, one from the tip and the other from the Fe, whose spin interactions with Ti are modulated by the radio‐frequency electric field. The Fe contribution is comparable to the tip, as revealed by its dominance when the tip is retracted, and tunable using a vector magnetic field. The new ESR scheme allows on‐surface individual spins to be addressed and coherently controlled without the need for magnetic interaction with a tip. This study establishes a feasible implementation of spin‐based multi‐qubit systems on surfaces. [ABSTRACT FROM AUTHOR]

xMgO–(30–x)BaO–69.5B2O3 glass systems were synthesized with the doping of transition metal ions (Mn2+) by applying the melt quench method. These glass systems are then observed using analysis by XRD, UV-VIS absorption and electron paramagnetic resonance. Mn2+ absorption spectrum has its own broadband at about 21000 cm–1 (476 nm), which is ascribed to be of 6A1g(S) → 4T1g (G) transition. The typical six-line hyperfine structure with a core at g ≈ 2.0 was observed in the Mn2+ EPR spectra. The close octahedral site symmetry for the Mn2+ contamination ions was established by spectroscopic examinations of the obtained data. Structural transformations were discovered using Fourier transform infrared and Raman spectra. Assessments were done on several physical parameters, together with density, refractive index, optical basicity, molar volume, energy gap, Urbach energy and interaction parameter. [ABSTRACT FROM AUTHOR]