Electrolytic-reduction ion water protects keratinocytes from hydrogen peroxide through radical scavenging activity and induction of AQP3 expression.

Skin exposed to ultraviolet light produces hydrogen peroxide (H2O2) 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 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.

On-Surface Atomic Scale Qubit Platform.

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.

Use of In-Situ ESR Measurements for Mechanistic Studies of Free Radical Non-Catalytic Thermal Reactions of Various Unconventional Oil Resources and Biomass.

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.

Multi-method dating reveals 200 ka of Middle Palaeolithic occupation at Maras rock shelter, Rhône Valley, France.

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).

Recent developments in materials and applications of triplet dynamic nuclear polarization.

Dynamic nuclear polarization (DNP) is a method for achieving high levels of nuclear spin polarization by transferring spin polarization from electrons to nuclei by microwave irradiation, resulting in higher sensitivity in NMR/MRI. In particular, DNP using photoexcited triplet electron spins (triplet-DNP) can provide a hyperpolarized nuclear spin state at room temperature and in low magnetic field. In this review article, we highlight recent developments in materials and instrumentation for the application of triplet-DNP. First, a brief history and principles of triplet-DNP will be presented. Next, important advances in recent years will be outlined: new materials to hyperpolarize water and biomolecules; high-sensitivity solution NMR by dissolution triplet-DNP; and strategies for further improvement of the polarization. In view of these developments, future directions to widen the range of applications of triplet-DNP will be discussed.

Effect of different initiators on the properties of diacetone acrylamide grafted starch-based adhesive.

Environmentally friendly and non-toxic bio-based adhesives are emerging as the most promising substitutes for petroleum-based adhesives, attracting increasing attention. This work involved the synthesis of a starch-based adhesive for particleboards by grafting diacetone acrylamide (DAAM) onto starch. The graft polymerization was initiated using three different initiators: ammonium persulfate (APS), hydrogen peroxide (H2O2)/ammonium ferrous sulfate system, and ceric ammonium nitrate (CAN). A comparative study was conducted to assess the varying effects of these initiators. The results showed that in the graft copolymerization of starch with DAAM, different initiators produced different types of free radicals, and CAN initiation produced alkyl radicals and long-chain alkyl radicals with a peak total spin value of 3.96 × 1015, and thus had the highest grafting efficiency and grafting rate of 72.59 % and 16.75 %, respectively. From the comparison of the total number of spins, it can be seen that CAN is more targeted for starch initiation. In addition, characterization results from Fourier transform infrared spectroscopy and confocal Raman spectroscopy showed that DAAM underwent a graft copolymerization reaction with starch. Notably, the adhesive initiated by CAN demonstrated the highest water resistance and mechanical strength, with an absorption thickness expansion and static bending strength of 8.52 % and 10.56 MPa, respectively.

Characterization of selenium-containing broccoli (Brassica oleracea L. var. italica planch) proteins and evaluation of antioxidant activity by electron spin resonance.

Selenoproteins found in selenium (Se)-enriched vegetables play a vital role in maintaining human health. In this study, four Se-containing broccoli proteins (Se-BP: albumin, globulin, prolamin, and glutelin) were continuous extracted by Osborne method. Three ultrafiltered fractions were subsequently obtained from the glutelin hydrolysate, composed of Se-contained broccoli peptides (Se-Bp) with different molecular weights (MW), namely, < 1 kDa, 1-3 kDa, and 3-10 kDa. Glutelin exhibited the highest protein yield (65.60 ± 1.07%), purity (78.39 ± 0.95%), nutritional value, organic Se content (88.05 ± 0.32% of total Se content), and Se speciation distribution (selenocystine, selenomethionine, methylselenocysteine, and selenoethionine). Additionally, the antioxidant activity of different MW of Se-Bp was assessed using electron spin resonance spectroscopy. The results revealed that antioxidant activity of the candidate peptide is dependent upon its Se content, amino acid composition, and MW, especially Se-Bp with MW of 1-3 kDa displayed the strongest free radical scavenging ability.

All-Electrical Driving and Probing of Dressed States in a Single Spin.

The subnanometer distance between tip and sample in a scanning tunneling microscope (STM) enables the application of very large electric fields with a strength as high as ∼1 GV/m. This has allowed for efficient electrical driving of Rabi oscillations of a single spin on a surface at a moderate radiofrequency (RF) voltage on the order of tens of millivolts. Here, we demonstrate the creation of dressed states of a single electron spin localized in the STM tunnel junction by using resonant RF driving voltages. The read-out of these dressed states was achieved all electrically by a weakly coupled probe spin. Our work highlights the strength of the atomic-scale geometry inherent to the STM that facilitates the creation and control of dressed states, which are promising for the design of atomic scale quantum devices using individual spins on surfaces.

Free radical production induced by visible light in live fruit flies.

Visible light triggers free radical production in alive and intact Drosophila melanogaster. We exposed fruit flies to red (613-631 nm), green (515-535 nm), and blue (455-475 nm) light while we monitored changes in unpaired electron content with an electron spin resonance spectrometer (ESR/EPR). The immediate response to light is a rapid increase in spin content lasting approximately 10 s followed by a slower, linear increase for approximately 170 s. When the light is turned off, the spin population promptly decays with a similar time course, though never fully returning to baseline. The magnitude and time course of the spin production depends on the wavelength of the light. Initially, we surmised that eumelanin might be responsible for the spin change because of its documented ability for visible light absorption and its highly stable free radical content. To explore this, we utilized different fruit fly strains with varying eumelanin content and clarified the relation of melanin types with the spin response. Our findings revealed that flies with darker cuticle have at least three-fold more unpaired electrons than flies with yellow cuticle. However, to our surprise, the increase in unpaired electron population by light was not drastically different amongst the genotypes. This suggests that light-induced free radical production may not exclusively rely on the presence of black melanin, but may instead be dependent on light effects on quinone-based cuticular polymers.

Crystal structures, electron spin resonance, and thermogravimetric analysis of three mixed-valence copper cyanide polymers.

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.

Cryogenic platform to investigate strong microwave cavity-spin coupling in correlated magnetic materials.

We present a comprehensive exploration of loop-gap resonators for electron spin resonance (ESR) studies, enabling investigations into the hybridization of solid-state magnetic materials with microwave polariton modes. The experimental setup, implemented in aPhysical Property Measurement Systemby Quantum Design, allows for measurements of ESR spectra at temperatures as low as 2 Kelvin. The versatility of continuous wave ESR spectroscopy is demonstrated through experiments on CuSO4⋅5H2O and MgCr2O4, showcasing the g-tensor and magnetic susceptibilities of these materials. The study delves into the challenges of fitting spectra under strong hybridization conditions and underscores the significance of proper calibration and stabilization. The detailed guide provided serves as a valuable resource for laboratories interested in exploring hybrid quantum systems through microwave resonators.

Li3V2(PO4)3 Cathode Material: Synthesis Method, High Lithium Diffusion Coefficient and Magnetic Inhomogeneity.

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.

[Mechanistic Analysis of Oxidative Stress-related Diseases Using Nitroxyl Radicals and Electron Spin Resonance].

Excessive production of reactive oxygen species (ROS) causes oxidative stress and is involved in the development and progression of a wide variety of diseases. Therefore, techniques for measuring oxidative stress are indispensable for analysis of the mechanisms of various diseases. The method involving ESR and the durable nitroxyl radical (ESR/spin probe method) is useful for this purpose, because the ESR signal intensity of the spin probe changes on reacting with ROS and other unstable radicals. In this review, the author's research applying the ESR/spin probe method to clarify disease mechanisms in vivo and in vitro is presented. The ESR signal of the probe injected into animals may decay through a few mechanisms besides reaction with ROS; thus, interpretation of the results is complicated. As the first approach to solving this problem, a probe resistant to enzymatic reduction by introducing a bulky group adjacent to the nitroxy group was created. The second approach was the use of a hydroxylamine probe which dominantly oxidized to nitroxyl radicals by reacting with superoxide anion radicals and oxidants. Using acyl-protected hydroxyl amine, it was demonstrated that sepsis model mice are under oxidative stress due to ROS production by activated phagocytes. On the other hand, it was shown in vitro that the UV-induced radical reaction of ketoprofen also occurs in lipid membranes, and that the reaction is related to ROS generation and membrane disruption. We believe that use of the ESR/spin probe method with ingenuity will clarify the mechanisms of various diseases.

Spectral diffusion of electron spin polarization in glasses doped with radicals for DNP.

Spectral diffusion of electron spin polarization plays a key part in dynamic nuclear polarization (DNP). It determines the distribution of polarization across the electron spin resonance (ESR) line and consequently the polarization that is available for transfer to the nuclear spins. Various authors have studied it experimentally by means of electron-electron double resonance (ELDOR) and proposed and used macroscopic models to interpret these experiments. However, microscopic models predicting the rate of spectral diffusion are scarce. The present article is an attempt to fill this gap. It derives a spectral diffusion equation from first principles and uses Monte Carlo simulations to determine the parameters in this equation. The derivation given here builds on an observation made in a previous article on nuclear dipolar relaxation: spectral diffusion is also spatial diffusion and the random distribution of spins in space limits the former. This can be modelled assuming that rapid flip-flop transitions between a spin and its nearest neighbour do not contribute to diffusion of polarization across the ESR spectrum. The present article presents predictions of the spectral diffusion constant and shows that this limitation may lower the spectral diffusion constant by several orders of magnitude. As a check the constant is determined from first principles for a sample containing 40 mM TEMPOL. Including the limitation then results in a value that is close to that obtained from an analysis of previously reported ELDOR experiments.

Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment.

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.

Conformational Heterogeneity of ß-Barrel Membrane Proteins Observed In Situ Using Orthogonal Spin Labels and Pulsed ESR Spectroscopy.

Outer membrane proteins (OMPs) of Gram-negative bacteria are involved in many essential functions of the cell. They are tightly packed in the outer membrane, which is an asymmetric lipid bilayer. Electron spin resonance (ESR) spectroscopic techniques combined with site-directed spin labeling (SDSL) enable observation of structure and conformational dynamics of these proteins directly in their native environments. Here we depict a protocol for site-directed spin labeling of ß-barrel membrane proteins in isolated outer membranes and intact E. coli using nitroxide, triarylmethyl (trityl), and Gd3+-based spin tags. Furthermore, subsequent continuous wave (CW) and orthogonal pulsed electron-electron double resonance (PELDOR) measurements are described along with experimental setup at Q-band (34 GHz), the data analysis, and interpretation.

Anti-inflammatory potential of remimazolam: A laboratory and clinical investigation.

BACKGROUND: Anesthetic agents, particularly intravenous anesthetics, may affect immune function and tumorigenic factors. We herein investigated whether the anti-inflammatory effects of anesthetic agents are attributed to their antioxidant properties. The antioxidant and anti-inflammatory effects of remimazolam, a new anesthetic, remain unclear. We hypothesized that remimazolam exerts anti-inflammatory effects due to its antioxidant properties, which may affect the postoperative inflammatory response. This retrospective clinical study examined this hypothesis using laboratory and clinical approaches. METHODS: The antioxidant effects of remimazolam and dexmedetomidine were assessed by electron spin resonance (ESR) spectroscopy, and postoperative inflammatory responses were compared in 143 patients who underwent transcatheter aortic valve replacement at Kindai University Hospital between April 2021 and December 2022. The primary endpoint was the presence or absence of the antioxidant effects of the anesthetics themselves using ESR. RESULTS: Remimazolam at clinical concentrations exerted antioxidant effects, whereas dexmedetomidine did not. Increases in C-reactive protein (CRP) levels on POD3 from preoperative values were significantly smaller in the remimazolam group than in the dexmedetomidine group (1.33 ± 1.29 vs. 2.17 ± 1.84, p = .014). CONCLUSIONS: Remimazolam exerted stronger anti-inflammatory effects than dexmedetomidine, and these effects were enhanced by its antioxidant properties, which may have affected postoperative CRP production.

Advancing the Design of Artificial Nano-organelles for Targeted Cellular Detoxification of Reactive Oxygen Species.

Artificial organelles (AnOs) are in the spotlight as systems to supplement biochemical pathways in cells. While polymersome-based artificial organelles containing enzymes to reduce reactive oxygen species (ROS) are known, applications requiring control of their enzymatic activity and cell-targeting to promote intracellular ROS detoxification are underexplored. Here, we introduce advanced AnOs where the chemical composition of the membrane supports the insertion of pore-forming melittin, enabling molecular exchange between the AnO cavity and the environment, while the encapsulated lactoperoxidase (LPO) maintains its catalytic function. We show that H2O2 outside AnOs penetrates through the melittin pores and is rapidly degraded by the encapsulated enzyme. As surface attachment of cell-penetrating peptides facilitates AnOs uptake by cells, electron spin resonance revealed a remarkable enhancement in intracellular ROS detoxification by these cell-targeted AnOs compared to nontargeted AnOs, thereby opening new avenues for a significant reduction of oxidative stress in cells.

Radical generation and bactericidal activity of nanobubbles produced by ultrasonic irradiation of carbonated water.

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.

Photolysis of dinotefuran in aqueous solution: Kinetics, influencing factors and photodegradation mechanism.

The environmental behaviour of neonicotinoid insecticides (NNIs) is of momentous concern due to their frequent detection in aquatic environment and their biotoxicity for non-target organisms. Phototransformation is one of the most significant transformation processes, which is directly related to NNIs exposure and environmental risks. In this study, the photodegradation of dinotefuran (DIN, 1-Methyl-2-nitro-3-(tetrahydro-3-furanylmethyl)-guanidine), one of the most promising NNIs, was conducted under irritated light in the presence of Cl-, DOM along with the effect of pH and initial concentration. The findings demonstrated that in ultra-pure (UP) water, the photolysis rate constants (k) of DIN rose with increasing initial concentration. Whereas, in tap water, at varied pH levels, and in the presence of Cl-, the outcomes were reversed. At the same time, lower concentration of DOM promoted DIN photolysis processes due to the production of reactive oxygen species, while higher concentrations of DOM inhibited the photolysis by the predominance of light shielding effects. The singlet oxygen (1O2) was produced in the photolysis processes of DIN with Cl- and DOM, which was confirmed by electron spin resonance (EPR) analysis. Four main photolysis products and three intermediates were identified by UPLC-Q-Exactive Orbitrap MS analysis. The possible photodegradation pathways of DIN were proposed including the oxidation by 1O2, reduction and hydrolysis after the removal of nitro group from parent compounds. This study expanding our understanding of transformation behavior and fate of NNIs in the aquatic environment, which is essential for estimating their environmental risks.