Pshenichnyuk, Stanislav A

Pshenichnyuk S.A., Asfandiarov N.L., Rakhmeyev R.G., Komolov A.S., Tereshchenko O.E.

Low-energy (0–14 eV) resonance electron interaction and fragment species produced by dissociative electron attachment (DEA) for enantiomeric forms of glutamic acid (Glu) are studied under gas-phase conditions by means of DEA spectroscopy and density functional theory calculations. Contrary to a series of amino acids studied earlier employing the DEA technique, the most abundant species are not associated with the elimination of a hydrogen atom from the parent molecular negative ion. Besides this less intense closed-shell [Glu – H]– fragment, only two mass-selected negative ions, [Glu – 19]– and [Glu – 76]–, are detected within the same electron energy region, with the yield maximum observed at around 0.9 eV. This value matches well the energy of vertical electron attachment into the lowest normally empty π* COOH molecular orbital of Glu located at 0.88 eV according to the present B3LYP/6-31G(d) calculations. Although the detection of asymmetric DEA properties a priori is not accessible under the present experimental conditions, “chirality non-conservation” can be associated with some decay channels. Evidently, the measured spectra for the L- and D-forms are found to be identical, the results, nevertheless, being of interest for the forthcoming experiments utilizing spin-polarized electron beam as a chiral factor in the framework of conventional DEA technique.

Polyakov N.E., Mastova A.V., Kruppa A.I., Asfandiarov N.L., Pshenichnyuk S.A.

Electron transfer plays a crucial role in living systems, including the generation of reactive oxygen species (ROS). Oxygen acts as the terminal electron acceptor in the respiratory chains of aerobic organisms as well as in some photoinduced processes followed by the formation of ROS. This is why the participation of exogenous antioxidants in electron transfer processes in living systems is of particular interest. In the present study, using chemically induced dynamic nuclear polarization (CIDNP) and dissociative electron attachment (DEA) techniques, we have elucidated the affinity of solvated and free electrons to glycyrrhetinic acid (GA)—the aglicon of glycyrrhizin (the main active component of Licorice root). CIDNP is a powerful instrument to study the mechanisms of electron transfer reactions in solution, but the DEA technique shows its effectiveness in gas phase processes. For CIDNP experiments, the photoionization of the dianion of 5-sulfosalicylic acid (HSSA2−) was used as a model reaction of solvated electron generation. DEA experiments testify that GA molecules are even better electron acceptors than molecular oxygen, at least under gas-phase conditions. In addition, the effect of the solvent on the energetics of the reactants is discussed.

Asfandiarov N.L., Muftakhov M.V., Pshenichnyuk S.A.

Asfandiarov N.L., Muftakhov M.V., Safronov A.M., Galeev R.V., Pshenichnyuk S.A.

The method of dissociative electron attachment (DEA) spectroscopy was used to study the attachment of electrons to 1-chloronaphthalene molecules. It has been established that the dominant channel for the decay of molecular ions is the formation of Cl– ions in three resonances at 0.7, 1.5, and 3.0 eV. Ions [M–H]– and [M–Cl]– are observed at energies from 3.5 to 8.5 eV and have two to three orders of magnitude lower formation cross sections. Long-lived molecular ions were not registered. Calculations in the DFT CAM B3LYP/6-311+G(d,p) approximation predict the presence of six stable anionic structures in which the chlorine anion is coordinated to the neutral residue via noncovalent H–Cl––H bonds. The electron affinity of the most stable of these structures coincides with the experimentally measured value EAa = 0.2771 ± 0.003 eV. These results agree with the previously obtained data on the DEA of molecules of bromine-substituted biphenyls, naphthalenes, and anthracenes and confirm the existence of anionic structures with non-covalent H–Hal–H bonds. Such non-covalent anion structures should be extremely reactive, which makes them promising for the synthesis of self-assembling hydrocarbon nanomembranes.

Komolov A.S., Lazneva E.F., Sobolev V.S., Pshenichnyuk S.A., Asfandiarov N.L., Zhizhin E.V., Pudikov D.A., Dubov E.A., Pronin I.A., Akbarova F.D., Sharopov U.B.

The surface topography and density of unoccupied electronic states at thermal deposition of ultrathin dibromo-bianthracene films on the ZnO surface have been studied. The electronic characteristics of unoccupied electronic states during growth of dibromo-bianthracene films to a thickness of 10 nm have been investigated by total current spectroscopy using a probe electron beam. The experimental dependences have been analyzed using theoretical calculation of the orbital energies for dibromo-bianthracene molecules by the method of density functional theory (DFT).

Elkin Y.N., Stepanova A.Y., Pshenichnyuk S.A., Manyakhin A.Y.

Plant specialized metabolites are small molecules known for their role in abiotic and biotic stress tolerance. Understanding of the individual functions of most of these metabolites remains unknown. A border of the root of annual plants is especially attractive to clarity how the plant roots withstand biotic and abiotic challenges. A main part of the metabolites in the root the plant Scutellaria baicalensis consists of the wide variety of methylated flavones. Eight most abundant of its, mono- and polymethylated, which present the beginning and end of the plant flavone biosynthesis pathway, respectively, were detected as phenoxide-ions over the root organs (bark, cambium, xylem and decayed core) by LС-MS. This inspection recovers their location within cambium and bark. The disposition of mono-methylated wogonin and oroxylin A with it’s the putative potency to form the o-quinon anions (reductants) provide chemical protection of the root from reactive oxygen species. The tetra- and penta-methylated flavones arrange a passive hydrophobic physical barrier of the root bark. Environment threats necessitate the plant to produce the methylated flavones, which resistance mechanisms are embedded in the structures of their molecules.

Pshenichnyuk S.A., Asfandiarov N.L., Markova A.V., Komolov A.S., Timoshnikov V.A., Polyakov N.E.

Electron-driven processes in isolated curcumin (CUR) molecules are studied by means of dissociative electron attachment (DEA) spectroscopy under gas-phase conditions. Elementary photostimulated reactions initiated in CUR molecules under UV irradiation are studied using the chemically induced dynamic nuclear polarization method in an acetonitrile solvent. Density functional theory is applied to elucidate the energetics of fragmentation of CUR by low-energy (0–15 eV) resonance electron attachment and to characterize various CUR radical forms. The adiabatic electron affinity of CUR molecule is experimentally estimated to be about 1 eV. An extra electron attachment to the π1* LUMO and π2* molecular orbitals is responsible for the most intense DEA signals observed at thermal electron energy. The most abundant long-lived (hundreds of micro- to milliseconds) molecular negative ions CUR– are detected not only at the thermal energy of incident electrons but also at 0.6 eV, which is due to the formation of the π3* and π4* temporary negative ion states predicted to lie around 1 eV. Proton-assisted electron transfer between CUR molecules is registered under UV irradiation. The formation of both radical-anions and radical-cations of CUR is found to be more favorable in its enol form. The present findings shed some light on the elementary processes triggered in CUR by electrons and photons and, therefore, can be useful to understand the molecular mechanisms responsible for a variety of biological effects produced by CUR.

Asfandiarov N. ., Rakhmeev R. ., Safronov A. ., Pshenichnyuk S. .

The formation and decay of molecular negative ions (MNIs) formed during resonant scattering of electrons by triclocarban molecules were studied by dissoiative electron attachment (DEA) spectroscopy. The most intense channel observed in the mass spectrum are MNIs formed at the thermal energy of trapped electrons with a lifetime relative to electron autodetachment of ~2800 μs. The experimental results were interpreted using CAM-B3LYP/6-311+G(d,p) calculations, which made it possible to reveal a number of important features of the geometry of molecular and fragment negative ions. Namely, the most stable geometry of MNIs is such that one of the chlorine atoms is coordinated with two hydrogen atoms of the structural element of urea. The charge on the chlorine atom is ~–0.7e–, which allows us to interpret this state as the result of the “roaming” of the chlorine atom in the MNI. According to calculations, the adiabatic electron affinity (EAa) of the triclocarban molecule is 1.66 eV. Evaluation of EAa in a simple Arrhenius approximation gives 1.2–1.4 eV. An analysis of the potential of the appearance of fragment ions with a C6H3Cl2NH2 structure made it possible to discover the noncovalent structure of these pseudo-MNIs, in which the chlorine atom is coordinated with two hydrogen atoms of the amino group.

Asfandiarov N.L., Muftakhov M.V., Pshenichnyuk S.A.

Dissociative electron attachment (DEA) to 1-chloroanthracene and 9-chloroanthracene was investigated under gas-phase conditions. In both compounds, the elimination of the chlorine anion is the dominant channel for the dissociation of molecular negative ions (NIs). The second most intense channel leads to the formation of molecular anions (Mˉ). The autodetachment lifetime of Mˉ was measured to be about 170 μs for both compounds. The widths of the Mˉ peaks indicate that molecular anions are formed via two resonances: at thermal electron energies and through a shape resonance at the energy of ∼0.5 eV. Adiabatic electron affinities were estimated in the framework of the simple Arrhenius model to be 0.86 eV for both molecules, the values being close to the theoretical predictions by DFT method of 0.90 eV and 0.93 eV for 1-chloroanthracene and 9-chloroanthracene respectively. Metastable negative ions are observed in the DEA spectra of both molecules, which testifies that the elimination of chlorine anions from molecular NIs appears on a time scale of several microseconds.

Brotsman V.A., Lukonina N.S., Rybalchenko A.V., Kosaya M.P., Ioffe I.N., Lysenko K.A., Sidorov L.N., Pshenichnyuk S.A., Asfandiarov N.L., Goryunkov A.A.

Abstract Acenaphtho[1,2-k]fluoranthene (1) is synthesized via tandem cyclization during the dehydrofluorination of 1,4-di(1-naphthyl)-2,5-difluorobenzene (2) on activated γ-Al2O3. Presence of residual hydroxyl groups in alumina reduce the yield of target product 1 because of the side hydrolysis of fluoroarenes with the formation a product of partial cyclization, 9-(1-naphthyl)fluoranthen-8-ol (1b). The formation of negative ions (NI) of compounds 1 and 2 in the gas phase is studied by means of dissociative electron attachment (DEA) spectroscopy. Long-lived molecular NIs 1 and 2 are registered at the thermal energies of electrons, and patterns of their fragmentation are established. The adiabatic electron affinities of compounds 1 and 2 are estimated in the Arrhenius approximation and equal 1.17 ± 0.12 and 0.71 ± 0.07 eV, respectively, which agree with data from quantum chemical modeling at the level of the density functional theory (DFT). Electronic transitions for compounds 1 and 2 are studied via optical absorption and fluorescence spectroscopy. Fluorescence quantum yields are measured, and the resulting data are interpreted according to the time dependent DFT. The electrochemical properties of compounds 1, 1b, and 2 are studied via cyclic voltamperometry, and the levels of boundary molecular orbitals are estimated on the basis of their formal potentials of reduction and oxidation.

Sharopov U., Abdusalomov A., Kakhramonov A., Rashidov K., Akbarova F., Turapova S., Kurbanov M., Saidov D., Egamberdiev B., Komolov A., Pshenichnyuk S., Kaur K., Bandarenka H.

In this study, we present the results of our investigation of fluorine and colloidal aggregate formation in the LiF/Si(111) system as a function of substrate temperature and electron and ion beams. Excitons generated by electron or ion irradiation will form a stable F-H pair, which subsequently forms aggregate centres before their coalescence into fluoride and colloidal macromolecules. Additionally, after annealing the LiF film, colloids and anionic complexes are formed on the surface. The experimental data show the formation of colloids after 5 min of annealing at a temperature of 75 °C. Furthermore, when the LiF films annealed at a temperature of 400 °C, chemical reactions on the surface, such as the formation of silicide, are excited. The obtained experimental data show that an increase in the target temperature during the formation of primary point defects and their association can be represented by the migration of their components on the surface.

Asfandiarov N.L., Muftakhov M.V., Pshenichnyuk S.A.

Resonance electron attachment in a series of brominated diphenyl ethers, namely 4-bromodiphenyl ether (BDPE), 4-bromophenyl ether (BPE), and decabromodiphenyl ether (DBDE), was investigated in the gas phase by means of dissociative electron attachment spectroscopy. In addition to channels of dissociation into stable fragments, long-lived molecular negative ions with an average lifetime relative to autodetachment of the order of 60 µs were found for the last two molecules. In the case of BDPE and BPE, the most intense dissociation channel is the bromine anion, and for DBDE—the [C6Br5O]− anion. The [C6Br5O]− anion sequentially decomposes with the elimination of the bromide anion on a microsecond time scale, which is confirmed by the registration of metastable ions with an apparent mass of 12.8 a.m.u. The electron affinity of the studied molecules and the appearance energy of fragment ions were estimated with CAM-B3LYP/6-311+G(d,p).

Pshenichnyuk S.A., Asfandiarov N.L., Rakhmeyev R.G., Safronov A.M., Komolov A.S.

Low-energy (0–15 eV) resonance electron interaction with isolated tetracyanoethylene (TCNE) molecules is studied in vacuo by means of dissociative electron attachment (DEA) spectroscopy. Despite this molecule being relatively small, the long-lived molecular anions TCNE− are formed not only at thermal electron energy via a vibrational Feshbach resonance mechanism but also via shape resonances with the occupation of the π4* and π5* molecular orbitals by an incident electron. Dissociative decays of TCNE− are mostly observed at incident electron energy above the π7* temporary anion state predicted to lie at 1.69 eV by means of B3LYP/6-31G(d) calculations combined with the empirical scaling procedure. Electron attachment to the π6* orbital (predicted at 0.85 eV) leads to the generation of long-lived TCNE− species, which can decay via two competing processes: extra electron detachment, which appears in hundreds of microseconds, or elimination of two cyano groups to form the [TCNE − 2(CN)]− negative fragment on a tens of microsecond timescale. The latter is accompanied by the generation of a highly toxic cyanogen molecule as a neutral counterpart. Since the electron transfer to the acceptor molecule TCNE plays a key role in the formation of single-molecule magnets, the present data are of importance to understand the long-term behavior and likely harmful effects produced by cyanide-based prospective materials.

Sitkov N., Ryabko A., Kolobov A., Maximov A., Moshnikov V., Pshenichnyuk S., Komolov A., Aleshin A., Zimina T.

Impedimetric biosensors are used for detecting a wide range of analytes. The detection principle is a perspective for the development of new types of analytical devices for biomolecular diagnosis of diseases. Of particular interest are biosensors with very high sensitivities, capable of detecting trace amounts of biomarkers or drugs in biological fluids. Impedimetric biosensors possess a potential for increased sensitivity, since their electrodes can be modified with nanostructured materials, in particular zinc oxide. In this work, a miniature biosensor with an array of zinc oxide nanorods synthesized by the hydrothermal method has been created. Protein A was immobilized on the resulting structure, which was previously tested for binding to omalizumab by capillary electrophoresis. Using impedance spectroscopy, it was possible to detect the binding of omalizumab at concentrations down to 5 pg/mL. The resulting structures are suitable for creating reusable biosensor systems, since ZnO-coated electrodes are easily cleaned by photocatalytic decomposition of the bound molecules. The biosensor is promising for use in Point-of-Care systems designed for fast, multimodal detection of molecular markers of a wide range of diseases.

Asfandiarov N.L., Galeev R.V., Pshenichnyuk S.A.

The processes of formation and decay of negative molecular ions (NMI) of p-fluoranil [2,3,5,6-tetrafluoro-1,4-benzoquinone (FA)] and p-chloranil [2,3,5,6-tetrachloro-1,4-benzoquinone (CA)] in the gas phase were investigated. In both cases, long-lived NMIs were found in two resonances, at thermal electron energies and in the region of 0.8–0.9 eV, with lifetimes relative to electron ejection of τ a ∼ 600 µs. The dissociation of molecular NIs with the formation of fragment ions [M-COF2]−, [M-CO]−, and Cl− proceeds at microsecond times, which is confirmed by the registration of the corresponding metastable ions. It is shown that the dependence of the lifetime of MNIs on the electron energy can be explained by the presence of a transition state at an energy of ∼0.5 eV.

Zeng R., Liu Z., Jiang Z., Xiao C., Zuo Y., Zhao J.

Liberti V., Randi P.A., Bettega M.H., Souza Barbosa A.

Chen J., Chakraborty D., Ončák M., Ptasinska S., Denifl S.

Thiazole derivatives are biologically relevant molecules, used also in pharmaceutical applications. Herein, we report results for electron attachment to 2-bromo-5-nitrothiazole (BNT) in the gas phase. Employing two crossed electron–molecule beam experiments, we determined the efficiency curves of various fragment anions as a function of the initial electron energy between about 0 and 10 eV as well as the emission angle and kinetic energy distributions of Br− and NO2− ions formed from a resonance near 4 eV. The experiments were supported by quantum chemical calculations, exploring possible dissociation pathways along with their reaction energies. We also compared the electron attachment characteristics of BNT with those of the native thiazole molecule by performing electron attachment experiments and calculations for this molecule as well. Compared to thiazole, which is primarily degraded only by electrons with kinetic energies between about 5 and 10 eV, BNT is susceptible to low-energy electrons near 0 eV with enhanced cross section for (dissociative) electron attachment. However, although BNT offers two localization sites with high electron affinity (Br and NO2 moieties), we do not find the corresponding anions as the dominant negatively charged species formed upon electron attachment. Instead, the reaction channels with an abstraction of Br and NO2 as neutral radicals prevail, accompanied by the opening of the thiazole ring due to the relatively weak C–S bond.

Bianco M., Losito I., Ventura G., Leoni B., Palmitessa O.D., Renna M., Santamaria P., Calvano C.D., Cataldi T.R.

Kathirvel A., Srinivasan R., Harini S., Ranjith N., Kumar G.S., Lalithambigai K., Atchudan R., Habila M.A., Aljuwayid A.M., Yun H.K.

Zirconium dioxide nanoparticles (ZrO2 NPs) have gained significant attention due to their excellent bioavailability, low toxicity, and diverse applications in the medical and industrial fields. In this study, ZrO2 NPs were synthesized using zirconyl oxychloride and the aqueous leaf extract of Toddalia asiatica as a stabilizing agent. Analytical techniques, including various spectroscopy methods and electron microscopy, confirmed the formation of aggregated spherical ZrO2 NPs, ranging from 15 to 30 nm in size, with mixed-phase structure composed of tetragonal and monoclinic structures. UV–visible spectroscopy showed a characteristic band at 281 nm with a bandgap energy of 3.7 eV, indicating effective stabilization by the phytochemicals in T. asiatica. EDX analysis revealed that the NPs contained 37.18 mol.% zirconium (Zr) and 62.82 mol.% oxygen. The ZrO2 NPs demonstrated remarkable photocatalytic activity, degrading over 95% of methylene blue dye after 3 h of sunlight exposure. Additionally, the ZrO2 NPs exhibited strong antibacterial effects, particularly against Gram-negative bacteria such as E. coli, and significant antioxidant activity, with low IC50 values for hydroxyl radical scavenging. In conclusion, the green synthesis of ZrO2 NPs using T. asiatica leaf extract is an effective, eco-friendly method that produces nanoparticles with remarkable antioxidant, antimicrobial, and photocatalytic properties, highlighting their potential for applications in water treatment, environmental remediation, and biomedicine.

Gao Y., Wang X., Cloutier P., Zheng Y., Sanche L.

Studies on radiosensitization of biological damage by O2 began about a century ago and it remains one of the most significant subjects in radiobiology. It has been related to increased production of oxygen radicals and other reactive metabolites, but only recently to the action of the numerous low-energy electrons (LEEs: 0–30 eV) produced by ionizing radiation. We provide the first complete set of G-values (yields of specific products per energy deposited) for all conformational damages induced to plasmid DNA by LEEs (GLEE (O2)) and 1.5 keV X-rays (GX(O2)) under oxygen at atmospheric pressure. The experiments are performed in a chamber, under humidity levels ranging from 2.5 to 33 water molecules/base. Photoelectrons from 0 to 30 eV are produced by X-rays incident on a tantalum substrate covered with DNA. Damage yields are measured by electrophoresis as a function of X-ray fluence. The oxygen enhancement ratio GLEE(O2)/GLEE(N2), which lies around 2 for potentially lethal cluster lesions, is similar to that found with cells. The average ratio, GLEE(O2)/GX(O2), of 12 for cluster lesions and crosslinks strongly suggest that DNA damages that harm cells are much more likely to be created by LEEs than any other initial species generated by X-rays in the presence of O2.

Lahlou R.A., Gonçalves A.C., Bounechada M., Nunes A.R., Soeiro P., Alves G., Moreno D.A., Garcia-Viguera C., Raposo C., Silvestre S., Rodilla J.M., Ismael M.I., Silva L.R.

Water mint (Mentha aquatica) is used in many formulations worldwide as a functional food and natural remedy to treat gastrointestinal disorders, lung diseases, and certain mental disorders such as epilepsy and depression. This study assessed the bioactivity of its infusion extract (INF) and hydroethanolic extract (HE) to highlight its health benefits. These extracts were analyzed for their chemical composition by HPLC-DAD-ESI-MSn, their antioxidant and antidiabetic properties, and their capacities to protect human erythrocytes against induced hemoglobin oxidation and lipid peroxidation. The effect on normal human dermal fibroblast (NHDF) cells and on the N27 rat dopaminergic neuron cell line was also assessed. The chromatographic analysis identified 57 compounds belonging to hydroxycinnamic acids, flavanones, flavone, and isoflavonoids. In respect to the biological potential, the Mentha aquatica extracts revealed a notable capacity for 2,2-diphenyl-1-picrylhydrazyl, nitric oxide, and superoxide radicals, as well as for the inhibition of α-glucosidase action and the protection of human erythrocytes against oxidative damage. Quantification revealed noteworthy phenolic content in both extracts. Additionally, the extracts demonstrated less cytotoxic effects regarding the NHDF and N27 cell lines. Overall, Mentha aquatica presents promising antioxidant activity and a spectrum of potential biological activities, underscoring its significance as a novel antioxidant candidate for applications in animal nutrition, human medicine, and natural product research in the pharmaceutical and nutraceutical industries.

Athaillah Z.A., Li X., Wang S.C.

Williams A.W., Gilmore K.

AbstractCross‐coupling reactions for constructing C−N bonds represent a pivotal advancement in chemical science. Traditional methodologies, including nucleophilic aromatic substitution (SNAr) and transition metal‐catalyzed cross‐couplings, have limitations concerning aryl scope, reliance on toxic and costly transition‐metal catalysts, and issues related to atom economy and waste generation from ligands and additives. In this work, we introduce a novel method for aminating neutral, electron‐rich, and electron‐deficient aryl halides, eliminating the need for transition metals. Our approach involves the activation of aryl halides using solvated electrons generated from granulated lithium and sonication. This serves as a sustainable source of reducing power, facilitating the efficient formation of C−N bonds under near ambient conditions. Competitive selectivity studies between halide and ester functionalities were explored. Reaction scope and conducted mechanistic studies which supported the proposed radical‐nucleophilic substitution (SRN1) mechanism for the reaction. Notably, the developed reaction has a highly competitive reductive dehalogenation pathway during the C−N coupling reaction, and this mechanistic divergency was thoroughly explored. This work not only broadens the scope of C−N coupling reactions which typically employs aryl bromides and iodides and rarely aryl fluorides which is also equally abundant, but also introduces a new way to do C−N coupling reactions using solvated electrons.

Muñoz-Jurado A., Escribano B.M.

Melatonin (MLT) is a hormone that exists in all living organisms, including bacteria, yeast, fungi, animals, and plants, many of which are ingested daily in the diet. However, the exact concentrations of melatonin in each of the foods and the effect on health of the intake of foods rich in MLT are not known. Therefore, the aim of this review was to gather the available information on the melatonin content of different foods and to evaluate the effect that this hormone has on different pathologies. The amount of MLT may vary depending on the variety, origin, heat treatment, processing, and analysis technique, among other factors. Dietary interventions with foods rich in MLT report health benefits, but there is no evidence that hormone is partially responsible for the clinical improvement. Therefore, it is necessary to evaluate the MLT content in more foods, as well as the effect that cooking/processing has on the amount of MLT, to estimate its total intake in a typical diet and better explore its potential impact on the health.

Kim D., Gwon S., Park K., Jeon E.

A series of Sr1−xDyxTi1−yNbyO3−δ (0.05 ≤ x, y ≤ 0.10) samples were fabricated using cold compaction, followed by sintering in a (95% N2 + 5% H2) reducing atmosphere. We studied the crystal structure and optical properties of Sr1−xDyxTi1−yNbyO3−δ using X-ray diffraction (XRD) with Rietveld refinement, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet−visible−near-infrared (UV−VIS−NIR) spectroscopy. The sintered Sr1−xDyxTi1−yNbyO3−δ had a tetragonal structure (I4/mcm space group). In the sintered samples, Ti ions existed as a mixture of Ti3+ and Ti4+, and Nb ions existed as a mixture of Nb4+ and Nb5+. The band-gap energies decreased with increasing Dy/Nb concentrations. The incorporation of Ti and Nb ions, the formation of both Ti3+ and Nb4+ ions, and the reduction in band-gap energies are likely highly effective for increasing the electron concentration and the corresponding electrical conductivity. Sr1−xDyxTi1−yNbyO3−δ with high electrical conductivity is suitable for energy and electronics applications.

Tseilikman V.E., Tseilikman O.B., Karpenko M.N., Traktirov D.S., Obukhova D.A., Shatilov V.A., Zhukov M.S., Manuilov G.V., Yegorov O.N., Aristov M.R., Lipatov I.A., Buksha I.A., Epitashvili A.E., Pashkov A.A., Novak J.

Background/Objectives: In post-traumatic stress disorder (PTSD), anxiety-like symptoms are often associated with elevated noradrenaline levels and decreased serotonin. Selective serotonin reuptake inhibitors (SSRIs) are frequently used to treat anxiety, but elevated serotonin has been observed in some anxiety disorders. This study investigates stress-induced anxiety as an immediate effect of chronic stress exposure using the predator stress paradigm. Methods: We examined serotonin levels, serotonin transporter (SERT), and 5-HT3A receptor gene expression in response to stress. The effects of SSRIs (paroxetine, sertraline) and resveratrol on these parameters were also analyzed, alongside co-treatment with resveratrol and sertraline. Results: Chronic stress exposure led to a significant increase in serotonin levels and upregulation of SERT and 5-HT3A receptor expression. SSRIs failed to prevent anxiety or reduce serotonin levels, partly due to suppressed SERT expression. Resveratrol downregulated SERT and 5-HT3A expression less than SSRIs but effectively reduced anxiety and restored serotonin, likely by upregulating MAO-A expression. Co-treatment with resveratrol and sertraline produced the strongest anxiolytic effect. Conclusions: Elevated serotonin and increased expression of SERT and 5-HT3A receptor genes are key factors in stress-related anxiety. Resveratrol and SSRIs target these mechanisms, suggesting potential therapeutic strategies for anxiety disorders. Future research will focus on further elucidating the serotonergic mechanisms involved and identifying new anxiolytic drug targets.

Arkhipov A., Trofimovich K., Arkhipov N., Gabdullin P.

The possible contribution of phonon drag effect to the thermoelectrically sustained potential of a heated nanoisland on a semiconductor surface was estimated in a first principal consideration. We regarded electrons and phonons as interacting particles, and the interaction cross-section was derived from the basic theory of semiconductors. The solution of the equation of motion for average electrons under the simultaneous action of phonon drag and electric field gave the distributions of phonon flux, density of charge carriers and electric potential. Dimensional suppression of thermal conductance and electron-phonon interaction were accounted for but found to be less effective than expected. The developed model predicts the formation of a layer with a high density of charge carriers that is practically independent of the concentration of dopant ions. This layer can effectively intercept the phonon flow propagating from the heated nanoisland. The resulting thermoEMF can have sufficient magnitudes to explain the low-voltage electron emission capability of nanoisland films of metals and sp2-bonded carbon, previously studied by our group. The phenomenon predicted by the model can be used in thermoelectric converters with untypical parameters or in systems for local cooling.

Pronin I.A., Plugin I.A., Kolosov D.A., Karmanov A.A., Yakushova N.D., Varezhnikov A.S., Komolov A.S., Lazneva E.F., Koroleva A.V., Moshnikov V.A., Kondratev V.M., Glukhova O.E., Korotcenkov G., Sysoev V.V.

Silva M.O., Moreira G.M., da Costa R.F., Bettega M.H.

Dos Santos K., Bertho G., Baudin M., Giraud N.

In recent years, there has been remarkable progress in the field of dissolution dynamic nuclear polarization (D-DNP). This method has shown significant potential for enhancing nuclear polarization by over 10,000 times, resulting in a substantial increase in sensitivity. The unprecedented signal enhancements achieved with D-DNP have opened new possibilities for in vitro analysis. This method enables the monitoring of structural and enzymatic kinetics with excellent time resolution at low concentrations. Furthermore, these advances can be straightforwardly translated to in vivo magnetic resonance imaging and magnetic resonance spectroscopy (MRI and MRS) experiments. D-DNP studies have used a range of 13C labeled molecules to gain deeper insights into the cellular metabolic pathways and disease hallmarks. Over the last 15 years, D-DNP has been used to analyze glutamine, a key player in the cellular metabolism, involved in many diseases including cancer. Glutamine is the most abundant amino acid in blood plasma and the major carrier of nitrogen, and it is converted to glutamate inside the cell, where the latter is the most abundant amino acid. It has been shown that increased glutamine consumption by cells is a hallmark of tumor cancer metabolism. In this review, we first highlight the significance of glutamine in metabolism, providing an in-depth description of its use at the cellular level as well as its specific roles in various organs. Next, we present a comprehensive overview of the principles of D-DNP. Finally, we review the state of the art in D-DNP glutamine analysis and its application in oncology, neurology, and perfusion marker studies.

Solov’yov A.V., Verkhovtsev A.V., Mason N.J., Amos R.A., Bald I., Baldacchino G., Dromey B., Falk M., Fedor J., Gerhards L., Hausmann M., Hildenbrand G., Hrabovský M., Kadlec S., Kočišek J., et. al.

Pshenichnyuk S.A., Asfandiarov N.L., Markova A.V., Komolov A.S., Timoshnikov V.A., Polyakov N.E.

Electron-driven processes in isolated curcumin (CUR) molecules are studied by means of dissociative electron attachment (DEA) spectroscopy under gas-phase conditions. Elementary photostimulated reactions initiated in CUR molecules under UV irradiation are studied using the chemically induced dynamic nuclear polarization method in an acetonitrile solvent. Density functional theory is applied to elucidate the energetics of fragmentation of CUR by low-energy (0–15 eV) resonance electron attachment and to characterize various CUR radical forms. The adiabatic electron affinity of CUR molecule is experimentally estimated to be about 1 eV. An extra electron attachment to the π1* LUMO and π2* molecular orbitals is responsible for the most intense DEA signals observed at thermal electron energy. The most abundant long-lived (hundreds of micro- to milliseconds) molecular negative ions CUR– are detected not only at the thermal energy of incident electrons but also at 0.6 eV, which is due to the formation of the π3* and π4* temporary negative ion states predicted to lie around 1 eV. Proton-assisted electron transfer between CUR molecules is registered under UV irradiation. The formation of both radical-anions and radical-cations of CUR is found to be more favorable in its enol form. The present findings shed some light on the elementary processes triggered in CUR by electrons and photons and, therefore, can be useful to understand the molecular mechanisms responsible for a variety of biological effects produced by CUR.

Rizzo A., Borra E.M., Ciciani L., Di Fino L., Romoli G., Santi Amantini G., Sperandio L., Vilardi I., Narici L.

AbstractFuture manned missions in deep space toward Moon and Mars represent one of the greatest challenges for radiological protection, which task is to mitigate risks for human life raised by the hostile space radiation environment. The prolonged exposure of astronauts to cosmic rays, mainly ion fields of galactic or solar origin, with a large dynamical behavior in time and space with a wide range of kinetic energies, may result in an unacceptable life risk for the next deep space manned missions. Indeed, these ions can deliver significant doses to astronauts by directly hitting human tissues as well as exposing them to secondary particles (neutron and high-LET nuclear fragments) produced by their interaction with space habitat materials. This radiation environment is very different from work environments on Earth, for example, in nuclear power plants or nuclear medicine departments, for which radioprotection was historically developed. Workers on Earth are mainly exposed to photons ($$\textrm{X}$$ X -rays and $$\gamma$$ γ -rays), to $$\alpha$$ α - and $$\beta$$ β -particles and neutrons, with lower energies than those in space. This difference marks a significant change in the methodological approach of the radioprotection in space compared to that on ground. The review presents the basic principles of radiation protection in space compared to that on ground and the strategies that must be implemented to mitigate risks in manned missions. In particular, the principles of the integrated multidisciplinary approach proposed by NASA and other space agencies for human space exploration are also discussed, with emphasis on the synergies among the various countermeasures proposed.

Zhang Y., Sheng Z., Xiao J., Li Y., Huang J., Jia J., Zeng X., Li L.

Since the first 70 years of reporting cancer chemotherapy, malignant tumors have been the second most common cause of death in children and adults. Currently, the commonly used anti-cancer methods include surgery, chemotherapy, radiotherapy, and immunotherapy. Although these treatment methods could alleviate cancer, they lead to different forms of side effects and have no particularly significant effect on prolonging the patients’ life span. Glycyrrhizic acid (GL), a native Chinese herbal extract, has a wide range of pharmacological effects, such as anti-cancer, anti-inflammatory, antioxidant, and immune regulation. In this review, the anti-cancer effects and mechanisms of GL are summarized in various cancers. The inhibition of GL on chemotherapy-induced side effects, including hepatotoxicity, nephrotoxicity, genotoxicity, neurotoxicity and pulmonary toxicity, is highlighted. Therefore, GL may be a promising and ideal drug for cancer therapy.

Sahoo L.K., Basak D., Mondal A.K., Satpati B., Karan S.K., Basu C.

The preparation of LiF targets on a self-supporting Ag backing (LiF/Ag) was discussed in detail using the vacuum evaporation process. The fabricated LiF targets were analyzed and efficiently characterized, with the target thickness measured by the energy loss of alpha particles through the target. The estimated thickness of LiF was ∼0.63±0.09μm. The non-uniformity of the targets was thoroughly checked with the help of a collimator, and the non-uniformity was within 6.50 %. The surface morphology and elemental composition were investigated using transmission electron microscope (TEM) and the Energy dispersive X-ray spectroscopy (EDX). Further x-ray photoelectron spectroscopy (XPS) was performed on the prepared targets and the presence of LiF phase has been confirmed by XPS. The targets were used to study the 7Li(p,n) reaction at the FRENA facility in Kolkata.

Li M., Xiang L., Li Y.

Asfandiarov N.L., Muftakhov M.V., Pshenichnyuk S.A.

Resonance electron attachment in a series of brominated diphenyl ethers, namely 4-bromodiphenyl ether (BDPE), 4-bromophenyl ether (BPE), and decabromodiphenyl ether (DBDE), was investigated in the gas phase by means of dissociative electron attachment spectroscopy. In addition to channels of dissociation into stable fragments, long-lived molecular negative ions with an average lifetime relative to autodetachment of the order of 60 µs were found for the last two molecules. In the case of BDPE and BPE, the most intense dissociation channel is the bromine anion, and for DBDE—the [C6Br5O]− anion. The [C6Br5O]− anion sequentially decomposes with the elimination of the bromide anion on a microsecond time scale, which is confirmed by the registration of metastable ions with an apparent mass of 12.8 a.m.u. The electron affinity of the studied molecules and the appearance energy of fragment ions were estimated with CAM-B3LYP/6-311+G(d,p).

Polyakov N.E., Leshina T.V.

The review presents an attempt to collect and systematize the available data on the antioxidant activity of glycyrrhizin obtained by various physicochemical methods and to stimulate further discussions on the mechanisms of its activity and prospects for its use as a multifunctional drug delivery system.

Pshenichnyuk S.A., Asfandiarov N.L., Rakhmeyev R.G., Safronov A.M., Komolov A.S.

Low-energy (0–15 eV) resonance electron interaction with isolated tetracyanoethylene (TCNE) molecules is studied in vacuo by means of dissociative electron attachment (DEA) spectroscopy. Despite this molecule being relatively small, the long-lived molecular anions TCNE− are formed not only at thermal electron energy via a vibrational Feshbach resonance mechanism but also via shape resonances with the occupation of the π4* and π5* molecular orbitals by an incident electron. Dissociative decays of TCNE− are mostly observed at incident electron energy above the π7* temporary anion state predicted to lie at 1.69 eV by means of B3LYP/6-31G(d) calculations combined with the empirical scaling procedure. Electron attachment to the π6* orbital (predicted at 0.85 eV) leads to the generation of long-lived TCNE− species, which can decay via two competing processes: extra electron detachment, which appears in hundreds of microseconds, or elimination of two cyano groups to form the [TCNE − 2(CN)]− negative fragment on a tens of microsecond timescale. The latter is accompanied by the generation of a highly toxic cyanogen molecule as a neutral counterpart. Since the electron transfer to the acceptor molecule TCNE plays a key role in the formation of single-molecule magnets, the present data are of importance to understand the long-term behavior and likely harmful effects produced by cyanide-based prospective materials.

Zhou M., Shen Y., Liu J., Lv L., Zhang Y., Meng X., Yang X., Zheng Y., Zhou Z.

The transition metal fluorides have huge advantage as anode due to the small atomic mass of the F atom. But the formation of Li–F rings reduced the cycle life, and the open-framework structure induced the high diffusion barriers. We designed a non-open framework 1T-TiF2 structure. The remaining 3d electrons of Ti induced the 1T-TiF2 structure has good electronic conductivity, and large formation energy of 1T-TiF2 structure block the formation of Li–F rings. The 1T-TiF2 structure could serve as anode in Li-ion, Na-ion, and K-ion batteries with high stiffness, superionic conductivity and long cycle life. Our calculate results indicated that the 1T-TiF2 anode has competitive theoretical capacitance (208.08 mA h g−1 for Li-ion battery, 277.45 mA h g−1 for Na-ion battery, and 208.08 mA h g−1 for K-ion battery). Furthermore, the good thermal, dynamic stability, oxidative corrosion resistance, and hydrophilicity confirmed the possibility of preparing 1T-TiF2 structure under laboratory conditions. Our study provides a reference for the light weighting of anodes.

Narayanan S J J., Tripathi D., Verma P., Adhikary A., Dutta A.K.

Verma P., Narayanan S J J., Dutta A.K.

Yu J., Peng J., Meng B., Wang X., Wang T., Jia X., Yang K., Yang N., Li L.

Uncontrollable lithium dendrite growth hinders lithium metal anode commercial application. Therefore, a copper current collector modified by nitrogen-doped biomass activated carbon ([email protected]) was designed to induce the uniform deposition of lithium ions. The abundant pore structure of activated carbon can limit the disordered growth of lithium dendrites, and the abundant nitrogen-containing functional groups provide a large number lithiophilic sites. The symmetrical cells of [email protected] exhibited up to 220 h of cycle life at 1 mA cm−2 and 1 mAh cm−2. The results provide guidance for the practical application and design of high-performance and low-cost lithium metal batteries.

Bi X., Yang L., Lin Y., Deng W., Jiang T., Zhang L., Lu Y., Yi W., Xie Y., Li M.

To compare the long-term efficacy and safety of glycyrrhizic acid preparation and hormone treatment in patients with autoimmune hepatitis, we enrolled 377 patients in a study that lasted from January 2009 to January 2020. After performing propensity score matching, we included 58 patients in the hormone group and 58 in the glycyrrhizic acid preparation group in statistical analysis. We then compared the ratio of sustained biochemical responses at 48 weeks after treatment. Adverse events, including some incidence of decompensated liver cirrhosis and liver cancer, were evaluated. The results showed that a total of 61.8% of treated patients achieved complete biochemical remission. The cumulative biochemical remission rate in the hormone group and glycyrrhizic acid preparation group showed no significant difference (62.3% vs. 60.7%, [Formula: see text], [Formula: see text]). At the end of follow-up, the total bile acid in the hormone group was significantly higher than that in the glycyrrhizic acid preparation group (8.9[Formula: see text][Formula: see text]mol/L vs. 5.6[Formula: see text][Formula: see text]mol/L, [Formula: see text], [Formula: see text]). The incidence of adverse reactions in the hormone group was significantly higher than that in the glycyrrhizic acid preparation group (31.03% vs. 15.52%, [Formula: see text], [Formula: see text]). In conclusion, compared with the hormone treatment, glycyrrhizic acid preparation might be a safe and effective treatment for autoimmune hepatitis.