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Despite the vast array of different geochronological tools available, dating the Paleolithic remains one of the discipline's greatest challenges. This review focuses on two different dating approaches: trapped charge and amino acid geochronology. While differing in their fundamental principles, both exploit time-dependent changes in signals found within crystals to generate a chronology for the material dated and hence, the associated deposits. Within each method, there is a diverse range of signals that can be analyzed, each covering different time ranges, applicable to different materials and suitable for different paleoenvironmental and archaeological contexts. This multiplicity of signals can at first sight appear confusing, but it is a fundamental strength of the techniques, allowing internal checks for consistency and providing more information than simply a chronology. For each technique, we present an overview of the basis for the time-dependent signals and the types of material that can be analyzed, with examples of their archaeological application, as well as their future potential. [ABSTRACT FROM AUTHOR]

The potential uses of Ligustrum robustum (Rxob.) Blume extract as a natural antioxidant to protect the quality of different oils during storage and frying process were studied. The results showed that L. robustum extract has been shown to retard the decline in the quality of both oils based on the tests of acid value, peroxide value, p‐anisidine value, color, volatile flavor, and fatty acid compositions, and the protective effect of L. robustum extract on the quality of peanut oil was better than that of palm oil. By the component analysis, L. robustum extract was found to have a total phenols content of 140.75 ± 1.52 mg/g, and ligurobustoside C was identified as the main phenolic compound. The thermogravimetric and differential scanning calorimetry results showed that L. robustum extract enhanced the oxidative stability of peanut and palm oils. In addition, Fourier transform infrared results indicated that L. robustum extract had protective effects on the C=C bond and ester bond of oil molecule. Moreover, by using electron spin resonance technique, L. robustum extract showed the ability to inhibit and scavenge alkyl‐free radicals in both oils. The present results suggested that L. robustum extract may protect the quality of oils during the storage and frying process by inhibiting the oxidation of unsaturated fatty acids and might be a potential natural antioxidant in the food industry. Practical Applications: The excellent antioxidant ability of Ligustrum robustum (Rxob.) Blume extract on the oxidation of different oils and its low price indicated that it could be used as a new low‐cost natural antioxidant in oil processing. [ABSTRACT FROM AUTHOR]

The kinetics of U(IV) produced by hydrazine reduction of U(VI) with platinum as a catalyst in nitric acid media was studied to reveal the reaction mechanism and optimize the reaction process. Electron spin resonance (ESR) was used to determine the influence of nitric acid oxidation. The effects of nitric acid, hydrazine, U(VI) concentration, catalyst dosage and temperature on the reaction rate were also studied. In addition, the simulation of the reaction process was performed using density functional theory. The results show that the influence of oxidation on the main reaction is limited when the concentration of nitric acid is below 0.5 mol/L. The reaction kinetics equation below the concentration of 0.5 mol/L is found as: −dc(UO22+)/dt=kc0.5323(UO22+)c0.2074(N2H5+)c−0.2009(H+). When the temperature is 50 ◦C, and the solid/liquid ratio r is 0.0667 g/mL, the reaction kinetics constant is k=0.00199 (mol/L)0.4712/min. Between 20 ◦C and 80 ◦C, the reaction rate gradually increases with the increase of temperature, and changes from chemically controlled to diffusion-controlled. The simulations of density functional theory give further insight into the influence of various factors on the reaction process, with which the reaction mechanisms are determined according to the reaction kinetics and the simulation results. [ABSTRACT FROM AUTHOR]

[Display omitted] Nitrogen and nickel are the main impurities in the type Ib synthetic diamonds obtained under high pressure and high temperature conditions using nickel-containing catalysts. Nitrogen enters the synthesized diamond from the air. The nickel/nitrogen ratio for the two types of diamonds, obtained with and without an aluminum getter that prevents the diamond crystal lattice from nitrogen penetration, was studied by electron spin resonance at 90 K. [ABSTRACT FROM AUTHOR]

Li3V2(PO4)3/Li3PO4 (LVPO/LPO) composites as cathodes for Li-ion batteries were synthesized by the hydrothermal method and subsequently annealed in an Ar atmosphere. The effect of Li3PO4 content on the crystal structure, morphology and the related magnetic and electrochemical properties of Li3V2(PO4)3/Li3PO4 composites, containing 7.5 wt% and 14 wt% of Li3PO4 (LVPO/LPO-7.5 and LVPO/LPO-14) was investigated. The microstructure and morphology of the obtained composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM); magnetic and electrochemical properties investigations were performed using the electron spin resonance and galvanostatic methods, respectively. It was shown that Li3V2(PO4)3/Li3PO4 composites exhibit a high discharge capacity, good cycle performance (105 and 120 mAh g−1 for the 200th cycle at 1C for LVPO/LPO-7.5 and LVPO/LPO-14, respectively), and insignificant changes in the surface morphology after 200 lithiation/delithiation cycles. Our results demonstrate that the increase in Li3PO4 content led to a decrease in the Li stoichiometry and magnetic inhomogeneity in Li3V2(PO4)3 phase; thus, the improvement in the electrochemical performance of LVPO/LPO composites due to incorporation of Li3PO4 can be attributed to their chemical and magnetic inhomogeneity. [ABSTRACT FROM AUTHOR]

Recent advances in scanning probe microscopy combined with electron spin resonance have revealed that localized electron spins on or near surfaces can be utilized as building blocks for the bottom-up assembly of functional quantum-coherent nanostructures. In this perspective, we review the recent advances, lay out advantages of this platform and outline the challenges that lie ahead on the way to the application of on-surface atomic spins to quantum information science and quantum computing.

Skin exposed to ultraviolet light produces hydrogen peroxide (H 2 O 2 ) and reactive oxygen species (ROS) that cause protein denaturation and other disorders. We investigated whether electrolytic-reduction 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 H 2 O 2 . Concentration-dependent scavenging of hydroxyl radical but no H 2 O 2 depletion were detected. An investigation of the expression of heme oxygenase-1, which is upregulated by oxidative response in cells, showed an increase through H 2 O 2 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 H 2 O 2 transporter. This analysis revealed that ERI enhances AQP3 expression in a concentration-dependent manner and is involved in the transport of intracellular H 2 O 2 to the extracellular space. In addition, ERI inhibited H 2 O 2 -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 H 2 O 2 .

This research aims to compare the dating results by thermoluminescence in comparison with the electron spin resonance techniques. We also intended to resolve the discrepancy on the precision being measured between these two. Based upon the archaeological evidence, six portions of freshwater fossil shells, used as samples, contain calcium carbonate polymorphs acquired from six locations in Pa Toh Roh Shelter archaeological site, Khao Han cave, Satun province, Thailand. The approach requires two important quantities for accurate dating, namely the annual dose and the accumulated dose. Using neutron activation analysis, the annual doses of the shells from different depths were found to be 2.64±0.07 to 7.27±0.11 mGy per year. The accumulated dose is evaluated from calibrated TL and ESR intensity versus accumulated γ-dose. Linear regression was used to fit the dependence of TL intensity on dose with a linear saturation function. The TL intensity at 350∘C was used to estimate ages of the fossil shells from all depths. The ESR dating would be also available for aragonite calcite shells using the ESR signal of g = 2.0016. The accumulated dose was found to vary from 10.49±2.09 to 22.50±3.99 Gy and the calculated ages of the shells were between 3,094±551 to 4,479±666 years old. These results confirm that the freshwater fossil shells in the area date back to the Neolithic period are similar to those found in the nearby archaeological sites. In addition, the dates are in agreement with those results from the relative dating as reported by a government agency.

β-glucan has been shown to be effective for several diseases such as immune regulation and blood pressure suppression. Seaweed contains a β-1,3/1,6-glucan called laminaran. The present commercial source of β-glucan is black yeast; however, a fermentation process using organic carbon substrates makes production unsustainable, whereas macroalgae provide a sustainable alternative with the use of CO2 and seawater as growth substrates. However, bioactivity studies on laminaran are limited. We aimed to evaluate whether laminaran can scavenge reactive oxygen species (ROS) and attenuate cytotoxicity caused by clinical drugs such as indomethacin (Ind) and dabigatran (Dab). Electron spin resonance assay revealed that laminaran scavenged singlet oxygen (1O2) and superoxide anions (O2•−) directly but did not scavenge hydroxyl radicals (•OH). Mitochondrial ROS detection dye showed that laminaran scavenged mitochondrial O2•− produced upon administration of Ind or Dab. Moreover, significant reductions in •OH and peroxynitrate (ONOO−) levels were observed. Since •OH and ONOO− are generated from O2•− in the cells, laminaran could indirectly suppress the generation of •OH and ONOO− via the removal of O2•−. Both Ind and Dab induce cell injury via ROS production. Laminaran attenuated the cytotoxicity derived from these drugs and may represent a functional food with anti-aging and disease prevention properties.

Spin probes can be used to monitor biological membranes, including the penetration of different molecules into cells. The aim of the present studies was an investigation of the endocytosis process of two spin labels—2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) and 4-hydroxy-TEMPO (TEMPOL)—into yeast cells and a leukemia cell line (HL-60, ATCC CCL-240) by Electron Spin Resonance (ESR). The ESR method is helpful for the direct detection of free radicals. The cell incubation and endocytosis of spin probes were carried out at 310 K. In contrast, the ESR measurements of yeast cells and a leukemia cell line with spin probes were at 240 K. Spectral differentiation was observed; hence, the spin probes present in suspension and attached to the cell membrane could be distinguished. The ESR signal changes of spin probes depended on spin probe concentration, cell number, and type of cell (healthy/cancerous). Additionally, the effect of external factors (oxygen and vitamin C) on the ESR signal decay of spin markers in the cell solution was established. The experimental results prove that the spin probes (TEMPO and TEMPOL) could scavenge free radicals inside the cell. At the same time, the mechanism of spin probe interaction in suspension was determined based on the measurements at low temperatures. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) was synthesized using carboxylic acids including amino acids. The obtained PANIs were characterized by scanning electron microscopy, optical spectroscopy, and electron spin resonance. The selected carboxylic acids caused structural differences and carrier localization in the PANI. Appropriate carboxylic acid selection led to structural control and spreading of conductive polymers. [ABSTRACT FROM AUTHOR]

In this paper, we propose a two-dimensional thermometer module based on the Nitrogen-Vacancy (NV) centers in diamonds. The thermometer integrates four modules on one Printed Circuit Board (PCB) including a laser module and a corresponding voltage regulator circuit, a microwave module, a focusing module, and an acquisition module, and it has a constructed area of 6.4 ${\textit {cm}}^{{2}}$. In the process of integrating equipment, we made a signal amplifier module to improve the signal-to-noise ratio (SNR). Through the amplifier module, we realize a $\sim 25$ -fold increase in the fluorescence, and it successfully improved the SNR by $\sim 8.9$ -fold. Fixed Frequency Optical Detection of Magnetic Resonance (FF-ODMR) measures the relationship between temperature (T) and photoluminescence (PL) by scanning the temperature field at 2.84GHz. Which is the most direct display of the thermometer. We developed an algorithm for analyzing the thermometer sensitivity based on PL the SNR analysis. The thermometer temperature-field sensitivity of approximately ${19}\textit {nk}/{\textit {Hz}}^{{1}/{2}}$. [ABSTRACT FROM AUTHOR]

In this paper, we portray the simulation of continuous-wave electron spin resonance (ESR) of magnetic cobalt ferrite nanoparticles (CoFNPs) which were assembled using simple sol–gel auto-combustion synthesis and irradiated with gamma dose up to 100 kGy. An emphasis has been given for estimating the crystallite size ( t 311 ) by re-evaluating Debye–Scherrer's value with the Williamson–Hall extrapolation function (W–H plot) drawn from X-Ray Diffraction (XRD) data. Also, the lattice parameter was re-confirmed via N V s (1 / d) plots. The SEM images have supported the nanosize of the CoFNPs and the skewed histogram chart has suggested the average grain distribution range 96.18–123.49 nm ± 10. The topology of the samples was studied by the atomic force microscopy images. In the first derivative peak of ESR spectroscopy, an isotropic value, i.e. gyroscopic spitting factor (Lande's g-value), and line width (ΔHpp) were used to examine the γ-radiation damage in the investigated CoFNPs samples. The present analysis may help an individual to comprehend the innumerable intra-atomic and molecular constraints affecting the subsequent physical properties of ferrite nanoparticles. [ABSTRACT FROM AUTHOR]

The gamma radiation-induced defects in radiation intolerant and radiation tolerant Si/SiO2 were observed by electron spin resonance (ESR). The Pb and È defects appeared in radiation-intolerant Si/SiO2 after radiation, but only Pb defects appeared in radiation-tolerant Si/SiO2 before and after radiation. The experimental results showed that these defects were correlated with the way of oxidation, the dosage of 60Co radiation and the electrical bias field during radiation. The higher the radiation dosage, the higher the defect concentration. A quantitative relationship was found between defect concentration and radiation dosage. Besides, the △B (peak to peak) of Pb and È indicated that Pb is the defect with a slow electron spin relaxation time, while È is the defect with a fast electron spin relaxation time. Finally, the experimental results are explained qualitatively. [ABSTRACT FROM AUTHOR]

Isomorphic substitutions of extra-framework components in sodalite-group aluminosilicate minerals and their thermal conversions have been investigated using infrared, Raman, electron spin resonance (ESR), as well as ultraviolet, visible and near infrared (UV–Vis–near IR) absorption spectroscopy methods and involving chemical and X-ray diffraction data. Sodalite-related minerals from gem lazurite deposits (haüyne, lazurite, and slyudyankaite) are characterized by wide variations in S-bearing extra-framework components including SO42− and various polysulfide groups (S2●−, S3●−, S4●− radical anions, and S4 and S6 neutral molecules) as well as the presence of CO2 molecules. Heating at 700 °C under reducing conditions results in the transformation of initial S-bearing groups SO42− and S3●− to a mixture of S2−, HS−, S2●−, and S4●− and transformation of CO2 to a mixture of CO32− and C2O42− or HC2O4− anionic groups. Further heating at 800 °C in air results in the decomposition of carbonate and oxalate groups, restoration of the SO42− and S3●− groups, and a sharp transformation of the framework. The HS− anion is stable only under reducing conditions, whereas the S3●− radical anion is the most stable polysulfide group. The HS−-dominant sodalite-group mineral sapozhnikovite forms a wide solid-solution series with sodalite. The conditions required for the formation of HS−- and CO20-bearing sodalite-group minerals are discussed. [ABSTRACT FROM AUTHOR]

To face economic issues of the last ten years, free-radical photopolymerization (FRP) has known an impressive enlightenment. Multiple performing photoinitiating systems have been designed to perform photopolymerizations in the visible or near infrared (NIR) range. To fully understand the photochemical mechanisms involved upon light activation and characterize the nature of radicals implied in FRP, electron paramagnetic resonance coupled to the spin trapping (EPR–ST) method represents one of the most valuable techniques. In this context, the principle of EPR–ST and its uses in free-radical photopolymerization are entirely described. [ABSTRACT FROM AUTHOR]

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Magnetic properties of the submicron carbon-coated LiFe1−xMnxPO4 (x = 0, 0.01, 0.1) systems were investigated using the electron spin resonance (ESR) method. The observed ESR signal consisted of two broad resonance lines with a Lorentzian line shape for all samples. The temperature dependence character of the integral intensity of these lines changed significantly with increasing manganese concentration, indicating a change in the nature of the magnetic interactions between the manganese and iron ions. We suggest that the noticeable capacity loss observed in the LiFe1−xMnxPO4 systems with increasing Mn content can be explained by the random distribution of Mn ions and changes to the type of magnetic ordering in these systems, despite the attractiveness of the electrochemical Mn2+/Mn3+ pair compared with Fe+2/Fe+3. [ABSTRACT FROM AUTHOR]

Many scientific and technological applications make use of strong microwave fields. These are often realized in conjunction with microwave resonators that have small geometric features in which such fields are generated. For example, in magnetic resonance, large microwave and RF magnetic fields make it possible to achieve fast control over the measured electron or nuclear spins in the sample and to detect them with high sensitivity. The numerical analysis of resonators with small geometric features can pose a significant challenge. This paper describes a general method of analysis and characterization of surface microresonators in the context of electron spin resonance (ESR) spectroscopy and spin-based quantum technology. Our analysis is based on the Electric Field Integral Equation (EFIE) and the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) formulation. In particular, we focus on a class of resonator configurations that possesses extremely small subwavelength features, which normally would require an ultra-fine mesh.We present several efficient techniques to numerically model, solve, and analyze these types of configurations for both normal and superconducting structures. The validation of these techniques is established both numerically and experimentally by the S11 parameters as well as the provision of direct mapping of the resonator's microwave magnetic field component using a unique electron spin resonance micro-imaging method. [ABSTRACT FROM AUTHOR]

Gallstones were examined for 58 patients in Jilin, Jilin. It was found that gallstones from only one who suffered from cholecystectomy were composed of 20 spheroidal stones and they rarely exhibited three different types of surface appearances. Six representative powder samples were analyzed for gallstones compositions and Mn2+ using X-ray diffraction (XRD)/Infrared (IR) and electron spin resonance (ESR), respectively. The results suggested that all gallstones from this patient were identified by XRD to be gallstones consisting mainly of cholesterol and CaCO3 (GCCC). They rarely exhibited three different kinds of surface appearances corresponding to different concentration of trace Mn2+ in calcite (CMn2+/CCal): 18 dark/light brown spheres with smooth surfaces and CMn2+/CCal = 0–6 μg/g/%, a yellowish-brown huge sphere with a rougher surface and CMn2+/CCal = 30 μg/g/%, and an ashy sphere composed of tens of microspheres with the roughest surface and CMn2+/CCal = 60 μg/g/%. The difference in surface appearance showed significant association with CMn2+/CCal, and its increase made the gallstone's surface change from smooth to rough and to fade in color. The unbalanced and competitive Mn2+ accumulation could occur occasionally in individual stones owing to different affinities to Mn2+, resulting in the formation of a huge stone and an ashy sphere. These two aberrations caused by higher CMn2+/CCal played an important role in suppressing the crystalline growth of the majority of dark/light brown spheres. GCCC from a patient might have a prominent Mn2+ partitioning feature corresponding to different surface appearances. [ABSTRACT FROM AUTHOR]

A systematic structural study on the intercalation of the radical cation 2-(4-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-N-oxide (p-MPYNN) into a synthetic fluoromica clay named Somasif® ME 100, Na2xMg3.0−xSi4O10(FyOH1−y)2 (x = 0.33, y = 0.98), has been carried out. The guest–host interactions in these intercalation compounds have been characterized by X-ray powder diffraction and solid-state NMR of the constituent nuclei (23Na, 19F, 27Al and 29Si) of the Somasif lattice. The intercalation process can be quantitatively monitored using 23Na MAS-NMR. As a function of radical ion loading, different kinds of stacking arrangements can be realized, which modify the intermolecular interactions between the electron spins of the guest species, as probed by electron spin resonance (EPR) and 1H solid state nuclear magnetic resonance (NMR). The results are discussed in relation to previous literature data on similar systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Crystals of good homogeneity of FeIn 2x Cr 2-2x S 4 (0.6 ≤ x ≤ 1) were obtained using the CVT method. • Temperature-dependent FMR spectra for all samples was obtained in the temperature range 80 < T < 700 K. • The H R and Δ H P P parameters clearly show the changes produced by distortions and the anisotropies generated. • Long-range spin-glass-like behavior for the x=0.6 and 0.7 and a reentrant spin-glass type for x=0.9 and 1.0 was observed. • From 1/A N vs T curve we found three temperature regions bounded by temperatures named T 1 and T 2 related to In diffusion. Electron spin resonance (ESR) was employed to investigate the effects of composition and temperature on the FeIn 2x Cr 2-2x S 4 semiconductor system. The samples were synthesized using Chemical Vapor Transport (CVT), and their structural characteristics were analyzed through X-ray diffraction and Scanning Electron Microscopy (SEM). For magnetic characterization, magnetization curves M(H) and temperature-dependent magnetization curves M(T) were obtained under both zero-field and field cooling conditions. A paramagnetic behavior was observed for all samples above 180 K, transitioning to a potential long-range spin-glass-like behavior below this temperature. By comparing the results with those presented in the literature, we suggest a reentrant spin glass behavior for the samples with higher Cr concentration. The Electron spin resonance (ESR) spectra revealed asymmetric signals indicative of strong magnetic anisotropies. The inverse of the normalized area in the ESR spectra revealed three distinct regions above the Néel temperature; this observation is consistent with the sensitivity of the lattice parameters of indite. The study elucidates the intricate magnetic behaviors influenced by composition and temperature in the FeIn 2x Cr 2-2x S 4 semiconductor system, contributing to a deeper understanding of the material's properties. This comprehensive investigation, utilizing a range of analytical techniques, advances our knowledge of the system's magnetic characteristics and provides valuable insights for future research in related semiconductor materials. [ABSTRACT FROM AUTHOR]

Establishing chronologies of archaeological sites by using a single dating method may not always reliably constrain the age of a deposit or a fossil, as potential biases may naturally arise, particularly in complex sedimentary settings such as caves. In this study, we performed a multi-technique dating approach that targets different materials in two caves from the Cueva Mayor-Cueva del Silo karst system, Sierra de Atapuerca, Spain. Two new fossil teeth from lithostratigraphic unit LU4 (GE-I pit) at Galería de las Estatuas have been dated by combined U-series/ESR and Amino Acid Racemisation (AAR) methods. The former provides ages of 117 ± 13 and 87 ± 9 ka that agree with previous dating studies of this Neandertal site, confirming the assignment of level LU4 to Marine Isotope Stage (MIS) 5. In contrast, AAR analyses produce very scattered ages, pointing to significant post-burial chemical modifications in dentine. A first set of ages is presented for the Cata Litario pit at Sala de los Cíclopes, a palaeontological site formed exclusively of cave bear fossils belonging to the Middle Pleistocene species Ursus deningeri. We provide U-series/ESR and AAR ages for two bear teeth from lithostratigraphic unit LU5, and extended-range luminescence ages for the sediment deposits that host, and immediately underlie and overlie, the bear accumulation. Depositional ages of the sediment were obtained using single-grain thermally-transferred optically stimulated luminescence (TT-OSL) dating of individual quartz grains and post-infrared-infrared stimulated luminescence (pIR-IR) dating of K-feldspars. Several speleothems, both in situ and reworked fragments embedded in the different lithostratigraphic units, have additionally been dated by U-series to constrain the timing of the sequence formation. The results indicate that the sediment originally entered the cave between MIS-12 and MIS-10 (444 ± 28 ka to 367 ± 32 ka). Nevertheless, the AAR and U-series/ESR fossil ages, as well as some of the speleothem fragment ages from LUs 5 and 6 are significantly younger. Leaving aside methodologically questionable results for one of the bear tooth samples, the most reliable AAR and U-Series/ESR ages range from 287 ± 23 ka to 256 ± 24, while the speleothem fragments indicate several formation episodes between 444 ± 19 and 284 ± 8 ka. The apparent difference between the U-Series/ESR ages on the fossils and the luminescence ages on the host sediment are not likely to be wholly explained by uncertainties on uranium uptake modelling or gamma dose rate evaluation, and thus is most likely related to taphonomic processes or a complex site formation history. The presence of fossils and eroded speleothem clasts of younger age within these levels is consistent with either an event of prior erosion, transport and resedimentation of LUs 4, 5 and 6, and/or a complex post-depositional mixing history for the stratigraphic sequence at Cata Litario. This study highlights the importance of using different dating methods to reconstruct reliable chronological frameworks, and to understand the geological factors that can affect the dated materials. This includes the accumulation and taphonomic histories of fossils, post-depositional mixing or reworking processes affecting sediments during the residence time within the karst system. [ABSTRACT FROM AUTHOR]

Crystal lattice defects in quartz have long been exploited for age determination, yet also show potential for sediment provenance studies. Here, we introduce a novel method for tracking aeolian dust provenance by utilizing the natural accumulation of E1' and peroxy defect centers in quartz. Our approach is based on the previously observed premise that E1' and peroxy centers arise from Frenkel defect pairs, and that their concentration increases with the age of the quartz‐bearing source rock. We propose that these defect centers can be utilized as a characteristic feature of the source rock and consequently, for fingerprinting sediments derived from it. We successfully apply our new protocol to distinguish fine‐grained quartz extracted from loess deposits from two regions in Central Asia which are known to derive from different source material of differing age. Our method offers strong potential for identifying variability in source, both spatially and through time down sedimentary sequences. Plain Language Summary: Identifying the origins of dust deposits allows us to reconstruct sediment transport pathways which are essential for understanding past atmospheric circulation patterns. Here, we propose to exploit the characteristics of two naturally occurring defect centers in crystalline quartz, the E1', and peroxy centers, as a means to distinguish sediment deriving from different origins. These centers occur as pairs and are hypothesized to increase with the age of the quartz‐bearing rock. By this logic, the E1' and peroxy centers can be used to determine the lithic origins of sedimentary quartz in a similar way to detrital zircon‐based provenance techniques, while analyzing a more ubiquitous mineral (quartz). We apply our approach, which uses a simplified protocol for measurement in contrast to earlier studies, to successfully distinguish between loess (wind‐blown dust deposits) from two different basins in Central Asia. Our new method holds great potential in its application to loess sequences as well as other sedimentary archives. Key Points: New sediment provenance tool exploits E1' and peroxy paramagnetic defects in quartzNew proxy successfully differentiates quartz in loess from two different basins in Central AsiaPotential applications for identifying climate‐driven source change through time in loess and other sedimentary sequences [ABSTRACT FROM AUTHOR]

Magnetic resonance techniques at nuclei and electrons are applied to characterize the electronic structure and collective magnetic excitations throughout the magnetic phase diagrams of the lacunar spinels GaV4S8 and GaV4Se8 showing cycloidal, Néel‐type skyrmion lattice and ferromagnetically polarized phases. 71Ga nuclear magnetic resonance (NMR) provides a local probe of the rhombohedral distortion and the resulting uniaxial magnetic anisotropy via the detection of electric field gradients (EFGs) and hyperfine coupling at the gallium sites of these lacunar spinels. Broadband electron spin resonance (ESR) allows identifying clockwise, counterclockwise, and breathing modes of the skyrmion‐lattice phase supported by theoretical simulations. [ABSTRACT FROM AUTHOR]

Polymer self-healing films containing fragments of pillar[5]arene were obtained for the first time using thiol/disulfide redox cross-linking. These films were characterized by thermogravimetric analysis and differential scanning calorimetry, FTIR spectroscopy, and electron microscopy. The films demonstrated the ability to self-heal through the action of atmospheric oxygen. Using UV–vis, 2D 1H-1H NOESY, and DOSY NMR spectroscopy, the pillar[5]arene was shown to form complexes with the antimicrobial drug moxifloxacin in a 2:1 composition (logK11 = 2.14 and logK12 = 6.20). Films containing moxifloxacin effectively reduced Staphylococcus aureus and Klebsiella pneumoniae biofilms formation on adhesive surfaces. [ABSTRACT FROM AUTHOR]

Electron spin resonance (ESR) is a spectroscopic technique that detects unpaired electrons, such as the ones present in free radicals. When a calcified tissue is irradiated, free radicals are generated, like the CO2−. This paper presents a preliminary study on the application of this spectroscopic technique for monitoring bone mineralization processes during the bone repair in animal model, induced by polyurethane in two forms, as an occlusive membrane and as a bone grafting. In the first experiment, the ESR results and microscopic analysis demonstrate centripetal bone growth and advanced stage of bone regeneration in the treated group. In the second experiment, the ESR spectrum of collected bone pieces presents the superposition of the spectrum of the biomaterial and the radical CO2−. The separation of the components was made using spectral simulation, and the percentage of mature bone tissue in the defect region was determined through the comparison with the spectrum of the native bone. In both experiments, ESR provided results consistent with microscopic analysis, demonstrating the feasibility of the technique for monitoring bone regeneration. [ABSTRACT FROM AUTHOR]

In this study, natural tinaksite (K2Ca2NaTi[Si7O18OH]O) and tokkoite (K2Ca4[Si7O18OH](OH,F)) collected in charoite rocks of the Murun alkaline massif (Siberia, Russia) were examined by X-ray diffraction and optical and vibrational spectroscopic methods. A comparative analysis of the experimental diffraction patterns with respect to the calculated X-ray powder diffraction patterns was carried out for tinaksite and tokkoite powders. The shift in the diffraction peaks of tinaksite is explained by the smaller values of the unit cell parameters a and b as compared with those of tokkoite. A similar shift of the peaks is also observed in the Raman and infrared absorption spectra; however, this feature is explained by the difference in the chemical composition of the minerals. The shoulder in the absorption spectra at about 800 nm in tinaksite and 700 nm in tokkoite corresponds to the presence of Mn2+ and Fe3+ absorption bands, the presence of which determines the color of tinaksite and tokkoite. The luminescence band with a maximum at about 540–550 nm in the photoluminescence spectra is related to Mn2+ centers, while an additional band at about 610 nm can be associated with Ti3+ centers in tinaksite. The intensity of the Fe3+ ESR signal increases in both samples after heating, while the intensities of the bands associated with OH groups decrease in tinaksite and tokkoite. This characteristic is the result of iron oxidation and dehydrogenation reaction. [ABSTRACT FROM AUTHOR]

Gamma-ray irradiation, using the cobalt-60 isotope, is the most common radiation modality used for medical device and biopharmaceutical products sterilization. Although X-ray and electron-beam (e-beam) sterilization technologies are mature and have been in use for decades, impediments remain to switching to these sterilization modalities because of lack of data on the resulting radiation effects for the associated polymers, as well as a lack of education for manufacturers and regulators on the viability of these sterilization alternatives. For this study, the compatibility of ethylene vinyl acetate (EVA) multilayer films with different ionizing radiation sterilization (X-ray, e-beam, and gamma irradiation) is determined by measuring chemical and physical film properties using high performance liquid chromatography, differential scanning calorimetry, Fourier-Transform InfraRed spectroscopy (FTIR), surface energy measurement, and electron spin resonance techniques. The results indicate that the three irradiation modalities induce no differences in thermal properties in the investigated dose range. Gamma and X-Ray irradiations generate the same level of reactive species in the EVA multilayer film, whereas e-beam generates a reduced quantity of reactive species.

Metal-doped graphitic carbon nitride (MCN) materials have shown great promise as effective photocatalysts for the conversion of acetic acid to carbon dioxide under UV–visible irradiation and are superior to pristine carbon nitride (g-C3N4, CN). In this study, the effects of metal dopants on the physicochemical properties of metal-doped CN samples (Fe-, Cu-, Zn-, FeCu-, FeZn-, and CuZn-doped CN) and their catalytic activity in the photooxidation of acetic acid were investigated and discussed for their correlation, especially on their surface and bulk structures. The materials in the order of highest to lowest photocatalytic activity are FeZn_CN, FeCu_CN, Fe_CN, and Cu_CN (rates of CO2 evolution higher than for CN), followed by Zn_CN, CuZn_CN, and CN (rates of CO2 evolution lower than CN). Although Fe doping resulted in the extension of the light absorption range, incorporation of metals did not significantly alter the crystalline phase, morphology, and specific surface area of the CN materials. However, the extension of light absorption into the visible region on Fe doping did not provide a suitable explanation for the increase in photocatalytic efficiency. To further understand this issue, the materials were analyzed using two complementary techniques, reversed double-beam photoacoustic spectroscopy (RDB-PAS) and electron spin resonance spectroscopy (ESR). The FeZn_CN, with the highest electron trap density between 2.95 and 3.00 eV, afforded the highest rate of CO2 evolution from acetic acid photodecomposition. All Fe-incorporated CN materials and Cu-CN reported herein can be categorized as high activity catalysts according to the rates of CO2 evolution obtained, higher than 0.15 μmol/min−1, or >1.5 times higher than that of pristine CN. Results from this research are suggestive of a correlation between the rate of CO2 evolution via photocatalytic oxidation of acetic acid with the threshold number of free unpaired electrons in CN-based materials and high electron trap density (between 2.95 and 3.00 eV).

Electron spin resonance (ESR) of diluted Nd(3+) ions in the topologically nontrivial semimetallic (TNSM) YBiPt compound is reported. The cubic YBiPt compound is a non-centrosymmetric half Heusler material which crystallizes in the F43m space group. The low temperature Nd(3+) ESR spectra showed a g-value of 2.66(4) corresponding to a Γ6 cubic crystal field Kramers' doublet ground state. Remarkably, the observed metallic and diffusive (Dysonian) Nd(3+) lineshape presented an unusual dependence with grain size, microwave power, Nd(3+) concentration and temperature. Moreover, the spin dynamic of the localized Nd(3+) ions in YBiPt was found to be characteristic of a phonon-bottleneck regime. It is claimed that, in this regime for YBiPt, phonons are responsible for mediating the diffusion of the microwave energy absorbed at resonance by the Nd(3+) ions to the thermal bath throughout the skin depth (δ ≃ μm). We argue that this is only possible because of the existence of highly mobile conduction electrons inside the skin depth of YBiPt that are strongly coupled to the phonons by spin-orbit coupling. Therefore, our unexpected ESR results point to a coexistence of metallic and insulating behaviors within the skin depth of YBiPt. This scenario is discussed in the light of the TNSM properties of this compound.

[Display omitted] The ability to control the properties of monolayer protected gold nanoparticles (MPNPs) discloses unrevealed features stemming from collective properties of the ligands forming the monolayer and presents opportunities to design new materials. To date, the influence of ligand end-group size and capacity to form hydrogen bonds on structure and hydration of small MPNPs (<5 nm) has been poorly studied. Here, we show that both features determine ligands order, solvent accessibility, capacity to host hydrophobic compounds and interfacial properties of MPNPs. The polarity perceived by a radical probe and its binding constant with the monolayer investigated by electron spin resonance is rationalized by molecular dynamics simulations, which suggest that larger space-filling groups – trimethylammonium, zwitterionic and short polyethylene glycol – favor a radial organization of the thiolates, whereas smaller groups – as sulfonate – promote the formation of bundles. Zwitterionic ligands create a surface network of hydrogen bonds, which affects nanoparticle hydrophobicity and maximize the partition equilibrium constant of the probe. This study discloses the role of the chemistry of the end-group on monolayer features with effects that span from molecular- to nano-scale and opens the door to a shift in the conception of new MPNPs exploiting the end-group as a novel design motif. [ABSTRACT FROM AUTHOR]

Positron annihilation spectroscopy (PAS) is used for the quantification of cavities in a matrix. Although PAS is sometimes considered a nondestructive measurement method, it is worth investigating the interaction of positrons with the matrix during PAS. Here, we have demonstrated that defects are generated in silver-doped phosphate glasses during positron annihilation measurement and that radiophotoluminescence (RPL) is observed after irradiation. There is a linear correlation between the irradiation duration and the observed RPL intensity of the glasses. We observed RPL after a high irradiation dose even after conventional thermal annealing at 360 °C for 1 h. The formation of Ag2+ species detectable by electron spin resonance (ESR) was confirmed. From the concentration of ESR-active Ag2+ and Ag2 + species, it is expected that approximately 0.1% of Ag+ cations were changed after 5 days of positron irradiation. [ABSTRACT FROM AUTHOR]

The new sodalite-group mineral sapozhnikovite, ideally Na8(Al6Si6O24)(HS)2, was discovered in a hydrothermally altered urtite-like rock at Karnasurt Mountain, Lovozero alkaline massif, Kola Peninsula, Russia. The associated minerals are nepheline, aegirine, potassic feldspar, albite, kyanoxalite, natrolite, fluorapatite, fluorcaphite, lomonosovite (partially or completely altered to murmanite) and loparite-(Ce). Sapozhnikovite forms isolated colourless to pale greyish anhedral equant grains up to 5 mm across. The streak is white and the lustre is vitreous. Strong orange fluorescence under longwave UV radiation (λ = 330 nm) and weak yellow-orange fluorescence under shortwave UV radiation (λ = 245 nm) is observed. Sapozhnikovite is brittle, with a Mohs hardness of 5½. Cleavage is imperfect on (110). Density measured by flotation in heavy liquids is equal to 2.25(1) g⋅cm–3. The calculated density is 2.255 g⋅cm–3. Sapozhnikovite is characterised by infrared, Raman, electron spin resonance, NIR-Vis-UV absorption, and photoluminescence spectroscopy. The chemical composition is (wt.%, electron microprobe, H2O determined by gas chromatography of ignition products): Na2O 25.05, Al2O3 32.44, SiO2 37.58, HS 4.33, Cl 2.22, H2O 0.30, –O≡(Cl,HS) –1.55, total 100.37. The empirical formula is Na7.73Al6.08Si5.97O24(HS)1.25Cl0.60⋅0.16H2O. The crystal structure was determined using single-crystal X-ray diffraction data and refined to R1 = 1.62%. Sapozhnikovite is cubic, P $\bar{4}$ 3n, with a = 8.9146(1) Å, V = 708.45(2) Å3 and Z = 1. The new mineral is isostructural with sodalite. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.30 (37) (110), 3.638 (100) (211), 2.821 (14) (310), 2.572 (18) (222), 2.382 (16) (321) and 2.101 (29) (411). The mineral is named in honour of the Russian mineralogist and crystallographer Dr. Anatoly Nikolaevich Sapozhnikov (b. 1946). [ABSTRACT FROM AUTHOR]

Both tooth enamel and dentine contain hydroxyapatite, the mineral which provides the strong electron spin resonance (ESR) signal used in enamel dating. The radiation-induced signals in dentine are considerably weaker than those in enamel and also appear less stable. Clearly, enamel is preferred for ESR dating. Some teeth, however, do not possess enough enamel to date. Even if some enamel is present, dating the dentine yields additional age estimates for the tooth. While the dentine ESR signal is weak, its properties (e.g., dose response and response to power saturation) are the same as for enamel. Measurement can be improved by signal averaging. For the samples in this study, no significant signals from organic contamination were found, although the presence of organic material seriously complicated isothermal measurements of the signal lifetime. Evaluating the internal dose rate has been problematic, because U mobility affects dentine to a much greater extent than enamel. Moreover, multiple uptake events are more common in dentine. The best results were obtained with teeth aged between 40 and 400 ka. Dentine will not replace enamel as a dosimeter. Every new material that can be used, however, even in limited cases, widens the range of sites and samples that can be dated by ESR. [ABSTRACT FROM AUTHOR]

We have shown previously that exposing bacteria to tetrachlorocatechol (TCC) and sodium azide (NaN 3) together causes synergistic cytotoxicity in a biphasic mode. However, the underlying chemical mechanism remains unclear. In this study, an unexpected ring-contraction 3(2 H)-furanone and two quinoid-compounds were identified as the major and minor reaction products, respectively; and two unusual azido-substituted chloro- O -semiquinone radicals were detected and characterized as the major radical intermediates by complementary applications of direct ESR, HPLC/ESI-Q-TOF and high-resolution MS studies with nitrogen-15 isotope-labeled NaN 3. Taken together, we proposed a novel molecular mechanism for the reaction of TCC/NaN 3 : N 3 - may attack on tetrachloro- O -semiquinone radical, forming two transient 4-azido-3,5,6-trichloro- and 4,5-diazido-3,6-dichloro- O -semiquinone radicals, consecutively. The second-radical intermediate may either undergo an unusual zwitt-azido cleavage to form the less-toxic ring-contraction 3(2 H)-furanone product, or further oxidize to form the more toxic quinoid-product 4-amino-5-azido-3,6-dichloro- O -benzoquinone. A good correlation was observed between the biphasic formation of this toxic quinone due to the two competing decomposition pathways of the radical intermediate and the biphasic synergism between TCC and NaN 3 , which are dependent on their molar-ratios. This is the first report of detection and identification of two unique azido-substituted chloro- O -semiquinone radicals, and an unprecedented ring-contraction mechanism via an unusually mild and facile zwitt-azido rearrangement. [Display omitted] • Two azido-substituted chloro- O -semiquinone radicals were separated and identified. • The ring-contraction 3(2H)-furanone was the major product in TCC/NaN 3 reaction. • The major pathway for TCC/NaN 3 is an unusual mild and facile zwitt-azido rearrangement. • Both radical VII and quinoid II are responsible for the TCC/NaN 3 lethal synergism. • The halocatechol/azide reaction may be used as a new method to synthesize 3(2H)-furanones. [ABSTRACT FROM AUTHOR]

Zn1−xCdxO (x = 0, 0.001, 0.01, 0.1) nanoparticles were prepared using polyol technique. The prepared nanoparticles were characterized using X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), ultraviolet–visible absorbance spectroscopy (Uv–Vis), vibrating sample magnetometer (VSM) and electron spin resonance (ESR). XRD confirmed the purity of the prepared samples, where all the samples crystallized in single hexagonal wurtzite phase. The morphology of the nanoparticles is studied using SEM and HRTEM techniques. The Uv–vis studies showed a marked red shift in the energy gap values of the prepared samples with respect to the theoretical value. VSM measurements suggested that only Zn0.09Cd0.01O exhibit room temperature ferromagnetism, whereas, the other samples show diamagnetic behavior. ESR measurements spotlights on the presence of different types of defects in the prepared samples. [ABSTRACT FROM AUTHOR]

Novel functionalities can be achieved in nanostructured materials in proximity with other dissimilar materials. An interesting possibility along these composite heterostructures is offered by ferromagnets in proximity to materials that simultaneously undergo a metal-insulator transition (MIT) and structural phase transition (SPT). In this study, the temperature induced phase transition effect of VO2 films has been used to modulate the electron spin resonance (ESR) and spin switching behaviors of the perpendicular magnetized (Co/Pt)3 multilayers. With comparative investigation, a significant magnetization switching in the (Co/Pt)3 multilayers can be distinguished to be driven by the temperature induced SPT in the coupled VO2 films, which could lead to the switch of the magnetic easy axis from out-of-plane to in-plane direction. The SPT modulated magnetic anisotropy in the VO2 coupled magnetic multilayers can be further confirmed by the angular dependent ferromagnetic resonance (FMR) fields at different temperatures. This work explores the new-type strain modulation of spin dynamics with SPT in the hybrid heterostructures, which may benefit the development of next generation spintronics devices with novel functionalities.

This paper presents the results of the first intercomparison exercise performed by the Korea retrospective dosimetry (KREDOS) working group using electron paramagnetic resonance (EPR) spectroscopy. The intercomparison employed the alanine dosimeter, which is commonly used as the standard dosimeter in EPR methods. Four laboratories participated in the dose assessment of blind samples, and one laboratory carried out irradiation of blind samples. Two types of alanine dosimeters (Bruker and Magnettech) with different geometries were used. Both dosimeters were blindly irradiated at three dose levels (0.60, 2.70, and 8.00 Gy) and four samples per dose were distributed to the participating laboratories. Assessments of blind doses by the laboratories were performed using their own measurement protocols. One laboratory did not participate in the measurements of Magnettech alanine dosimeter samples. Intercomparison results were analyzed by calculating the relative bias, En value, and z-score. The results reported by participating laboratories were overall satisfactory for doses of 2.70 and 8.00 Gy but were considerably overestimated with a relative bias range of 10–95% for 0.60 Gy, which is lower than the minimum detectable dose (MDD) of the alanine dosimeter. After the first intercomparison, participating laboratories are working to improve their alanine-EPR dosimetry systems through continuous meetings and are preparing a second intercomparison exercise for other materials.

Subject and Purpose. One of the ways to gain in the efficiency of the hyperthermia technique is through the synthesis of new magnetic nanomaterials offering high coercive force without affecting biocompatibility. A proven technology is the doping of biocompatible materials, such as Fe3O4, with atoms of highly coercive substances, such as Co atoms. Despite it has been the theme of much investigation, magnetic state of such nanoparticles is still not completely understood. The present study is devoted to the magnetic and magnetic resonance properties of Fe1–xCoxFe2O4 nanoparticles synthesized by the precipitation from diethylene glycol at two, T = 200 °C and 500 °C, temperatures. The purpose is to study magnetic and magnetic resonance properties of Fe1-xCoxFe2O4 nanoparticles at various concentrations x. Method and Methodology. The magnetometric method and the electron spin resonance method were employed to obtain, correspondingly, magnetic hysteresis loops of magnetic nanoparticles and ferromagnetic resonance (FMR) spectra in the frequency band f = 8…20 GHz at the temperature T = 294 K. Transmission electron microscopy was used for nanoparticle observations. Results. The analysis of the measuring results has shown that among Fe1–xCoxFe2O4 nanoparticle samples with concentrations x = 0.0, 0.5, and 1.0, the total magnetic anisotropy field at x = 0.5 is the largest of the three because its crystalline anisotropy field is the largest compared to x = 0.0 and 1.0. Conclusion. The presented results have advanced our understanding of the fundamental interaction between magnetic Co and Fe atoms inside the crystal lattice of AFe2O4, where A is Co or Fe. The gained knowledge can contribute to the development of magnetically controlled high-frequency filters and frequency selectors.

In order to explore the influence of different oxygen concentrations in goaf on the micro-characteristics of low-temperature oxidation process of coal, a self-built low-temperature oxidation simulation experimental system was used to simulate the natural oxidation state of coal at different depths of goaf. Based on electron spin resonance spectroscopy(ESR) technology, the free radicals in coal oxidation at low temperature under different oxygen concentrations were analyzed, and the release of gaseous products in coal oxidation process was determined. The results show that at the temperature node of 130 ℃, the change is from slow to fast. Coal body changes from slow oxidation to fast oxidation, but the g factor is between 2.001 41 and 2.002 034, with little change. With the increase of oxygen concentration, the variation trend of each parameter with oxidation temperature remains unchanged, but the overall variation increases gradually. When the oxygen concentration is less than 9%, the reaction of free radicals is slow at low temperature, and the generation of CO lags behind obviously. When oxygen concentration is more than 9%, the probability of coal-oxygen combination increases. The increase of temperature is more likely to stimulate the free radical reaction, and the CO concentration increases exponentially.

Subject and Purpose. Synthesis of biological sorbents has become one of the ways to solve the problem of environment contamination with heavy metals. Today, studying properties of biosorbents with injection of magnetic nanoparticles is important. Thus, injection of magnetic nanoparticles of magnetite (Fe3O4) improves absorption properties of biosorbents. The subject of the present work is magnetic resonance properties of nanoparticles inside biosorbents, such as macromycetes like Pleurotus ostreatus. The purpose is to examine these magnetic resonance properties and analyze the state of magnetite nanoparticles inside Pleurotus ostreatus. Methods and Methodology. The X-band Electron Spin Resonance (ESR) method is employed to register ferromagnetic resonance (FMR) spectra at T = 294 K. TEM-images of magnetic nanoparticles are made in the transmission electron microscope. Mathematical modeling for the properties of the arising clusters of magnetic Fe3O4 nanoparticles inside macromycetes Pleurotus ostreatus is performed using a phenomenological model upon the well-known Kittel equation. A model enhancement is proposed in the case of interacting nanoparticles inside an ellipsoidal magnetic cluster. Results. It has been shown that Fe3O4 nanoparticles are well absorbed by macromycetes and gather into structural clusters regardless of the concentration of magnetic nanoparticles injected. These magnetic clusters of magnetic nanoparticles have ellipsoidal shapes with an aspect ratio of 3:1:1. The developed mathematical model makes it possible to obtain dimensions of magnetic clusters from the FMR spectra and evaluate their shape and mutual magnetic interaction. The mathematical modeling results are in good agreement with TEM-images of these clusters inside Pleurotus ostreatus. As a result of modeling are in good agreement with the TEM-images of these clusters inside Pleurotus ostreatus. Conclusion. The presented results will contribute to the development of non-destructive testing of the state of biological sorbents using magnetic resonance radio spectroscopy methods.