bluuebunny/crossref_metadata_2025 huggingface dataset:
Determining nexus between monetary policy transmission channels and GDP of Pakistan
Authors: Hussain Muneer , Shah Shoaib , Durrani Zohair , Hassan Mir
Published: April 2024

The purpose of this research is to analyze long run and short run relationship of monetary policy transmission channels with GDP of Pakistan and research contains four channels that are mentioned in SBP and variables representing those channels are. Exchange rate, imports, interest rate, SBP advances and KSE 100 index which are independent variables and the GDP is taken for output as dependent variable and annual data from 1991-2017 is used. The results shows that there is co-integration among variables and therefore VECM was applied which shows significant long run relationship of independent variables with GDP as well as there is short run relationship with GDP, also exchange rate is very volatile with GDP. Further model specification is also used and results are meeting with assumptions of econometrics
Development of Forbush Decreases Associated
with Coronal Ejections from Active Regions and non-Active Regions
Authors: Melkumyan A. A. , Belov A. V. , Abunina M. A. , Shlyk N. S. , Abunin A. A. , Oleneva V. A. , Yanke V. G.
Published: April 2024

In this paper, we study the development of Forbush decreases associated with coronal mass ejectionsfrom active regions accompanied by solar flares and filament eruptions from non-active regions usingthe database of Forbush effects and interplanetary disturbances created at IZMIRAN. We compared thedevelopment of two types of Forbush decreases during solar cycles 23–24, the maxima of these cycles, andthe minimum between them. Using statistical methods, we studied the distributions of time intervals from thebeginning of the Forbush decrease to registration: the minimum cosmic ray density, the maximum hourlydecrease in density, the maximum cosmic ray anisotropy, the maximum solar wind velocity, the maximumstrength of the interplanetary magnetic field, and the minimum of the Dst index. The difference in the developmentof two types of Forbush decreases was compared when the interplanetary disturbance contains ordoes not contain a magnetic cloud near the Earth. The results showed that flare-associated events developfaster than filament-associated events, even at close values of the solar wind parameters. The difference in thedevelopment of two types of Forbush decreases is more noticeable in the case of the presence of a magneticcloud near the Earth’s orbit. The largest difference between the time parameters in the two types of events isobserved for the time of registration of the maximum intensity of the interplanetary magnetic field. The mainphase of the two types of Forbush decreases is the same at the solar cycle 23 maximum and longer for filament-associated events at the cycle 24 maximum and 23–24 minimum. Considering all time parameters, thedifference in the development of the two types of Forbush decreases is more noticeable at the maximum ofcycle 23 and at the minimum of cycle 23–24 than at the maximum of cycle 24
Fine Structures of Type-IV Solar Radio Bursts Associated
with Stationary and Moving Sources
Authors: Fomichev V. V. , Chernov G. P.
Published: April 2024

Various types of fine structure in the continuum emission of type-IV radio bursts are considered asapplied to different types of radiation sources, both stationary and moving. In the case of stationary sources,the origin of the fine structure is associated both with processes in individual magnetic loops (quasi-periodicacceleration and magnetohydrodynamic waves), and with large-scale processes associated with the propagationof magnetohydrodynamic disturbances, the formation of loop arcades, and processes of discrete accelerationof particles synchronous with them, causing the pulsating nature of radio emissions. For the case of amoving source, the generation mechanism largely depends on the magnetic structure of the source (anexpanding magnetic arc or an isolated plasma cloud). In this case, the connection with coronal mass ejectionsand shock waves is also important. Secondary pulsations are explained by a magnetohydrodynamic fluctuationsource in the form of a magnetic loop or cloud. The absence of other fine structures in the continuum ofmoving type-IV bursts may be due to the critical angle of the loss cone for the excitation of whistlers
Selection of the Solar-Diurnal Anisotropy of Cosmic Rays
by Local and Global Methods
Authors: Belov A. V. , Shlyk N. S. , Abunin M. A. , Abunin A. A. , Oleneva V. A. , Yanke V. G. , Melkumyan A. A.
Published: April 2024

According to the data of Moscow neutron monitor, using harmonic analysis, the characteristics ofthe solar-diurnal anisotropy of cosmic rays on quiet days have been obtained for a long period from 1965 to2020. It has been established that the average diurnal variation of cosmic rays at the Moscow neutron monitoris almost completely described by two harmonics of the solar-diurnal anisotropy and does not contain signsof other influences. A comparison with the average daily characteristics of the equatorial component of cosmicrays vector anisotropy, obtained from the data of the worldwide neutron monitor network using the globalsurvey method showed a good agreement between the results of the two methods. From a comparison of localand global results, estimates were obtained for the coupling coefficients of the first harmonic of the cosmicray anisotropy for the Moscow neutron monitor, and a new experimental method for calculating the couplingcoefficients of individual detectors was proposed. The limitations of the local method, as well as the possibilityof continuing and expanding this study, have been discussed and justified
Effect of Earthquake Preparation on Changes
in Meteorological Characteristics
(Based on the Example of the 2003 Chuya Earthquake)
Authors: Shitov A. V. , Pulinets S. A. , Budnikov P. A.
Published: April 2024

In this paper, we analyze the effect of the preparation of the Chuya earthquake on September 27,2003, the strongest event in the Altai-Sayan folded region for the entire instrumental period of seismologicalobservations, on meteorological characteristics (temperature, relative humidity, atmospheric chemicalpotential correction, latent heat of evaporation, and the mean and dispersion values of these data) and theirspectral characteristics in the Gorny Altai region. The meteorological and spectral characteristics are shownto change for a certain time before the main shock. The spectral characteristics distinctly change both duringthe preparation of the main shock and during the aftershock process.
A Nonlinear Dependence on the Geomagnetic Activity of the Ratio
of the Maximum Stream Flux of Charged Particles
in a Geostationary Orbit to the Minimum Stream Flux
Authors: Smolin S. V.
Published: April 2024

A new mathematical model was proposed using an ordinary differential equation that analytically(when the index of geomagnetic activity Kp = const or Kp ≈ const) or numerically (if Kp(t) ≠ const) describesperpendicular (for a pitch angle of 90°) differential or integral fluxes of relativistic electrons in a geostationary(geosynchronous) orbit, as well as in any circular orbit in the Earth’s magnetosphere. The model assumes thatthe fluxes depend on the local time LT in orbit, the Kp, MacIlvwaine parameter and L, and the perpendiculardifferential flux or integral flux of relativistic electrons taken at 0000:00 LT. We use observations of relativistic(2 MeV) electron fluxes averaged over the local time hour along the orbit of the GOES spacecraft from 1995to 2009. The model is compared with these data. Almost perfect agreement was obtained for observationswith the model, where the prediction efficiency of predicting the accuracy of the model at PE = 0.9989. Usingsimilar data from the GOES 10 allows one to obtain PE = 0.9924. The proposed formulas make it possible tofind, for example, the average value of the perpendicular integral flux of relativistic electrons per day and topredict the maximum perpendicular integral flux of relativistic electrons in the geostationary orbit approximately1 day ahead. The nonlinear effect is theoretically predicted in the form of a nonlinear dependence ofthe ratio of the maximum perpendicular integral flux to the minimum flux of charged particles in the geostationaryorbit from the Kp-index of geomagnetic activity. Thus far, comparison of the model has been madewith the averaged integral relativistic electron flows fluxes produced for the 0 ≤ Kp 6 range with a predictedmaximum flow flux ratio of 24.4139 times at Kp = 8 and with the prediction efficiency of predicting the accuracyof the nonlinear effect PE = 0.8678.
Effectiveness of the Relative -Barbier Parameter
in the Search for Ionospheric Precursors of Earthquakes
Authors: Pulinets S. A. , Khegai V. V. , Legen’ka A. D. , Korsunova L. P.
Published: April 2024

A study of temporal variations of the complex relative δ-Barbier parameter (δBarbier) was carried outto evaluate its effectiveness in the search for seismo-ionospheric precursors. For this purpose, its behavior(according to 15-min measurements of ionospheric parameters) was considered before two strong earthquakesfor which seismo-ionospheric precursors had already been detected. The first earthquake (with magnitudeM = 6.3) occurred on April 6, 2009 (L’Aquila, Italy) at an epicentral distance of ~93 km from the Romeground-based vertical ionospheric sounding station, and the second earthquake (with magnitude M = 7.2)occurred on January 30, 2016, while its epicenter was ~117 km from the ground-based vertical ionosphericsounding station located on the territory of the Paratunka Kamchatka complex geophysical observatory. Inboth cases, specific features were identified in the behavior of the δBarbier parameter that coincided in timewith the previously detected ionospheric precursors of these earthquakes. This allows us to conclude that theeffectiveness of using the δBarbier parameter in the search for seismo-ionospheric precursors has been successfullyverified
Hysteresis Phenomena in the Relationship
between the Cosmic Ray Cutoff Rigidity and Parameters
of the Magnetosphere during a Storm on May 15, 2005
Authors: Danilova O. A. , Ptitsyna N. G. , Tyasto M. I.
Published: April 2024

Variations in the cutoff rigidities of cosmic rays (ΔR) depending on the parameters of the solarwind, the interplanetary magnetic field (IMF), and geomagnetic activity were studied at different phases ofthe strong magnetic storm on May 15, 2005. We found that the trajectories ΔR, i.e., the successive values thatΔR takes depending on the parameters under study during the main phase of the storm did not coincide withthe trajectories in the recovery phase, which led to the formation of hysteresis loops. The clearest hysteresisloops are formed for the relationship between ΔR and the Bz component of the IMF, the density and pressureof the solar wind, and the Dst index of geomagnetic activity. The area of the hysteresis loops increases withthe latitude of the cosmic ray observation station.
Rotation of a Long-Lived Coronal Hole in Solar Cycle 24
Authors: Andreeva O. A. , Malaschuk V. M.
Published: April 2024

This paper discusses the results of a statistical study of the rotation characteristics of a long-livedgiant coronal hole. The study is based on observation data obtained by the Atmospheric Imaging Assemblyin the Fe XII 19.3 nm line aboard the Solar Dynamics Observatory spacecraft during the period from June2015 to March 2017; this was 24 Carrington revolutions. Four stages of the development of a coronal hole areconsidered separately: formation, two phases of a developed coronal hole, and the final phase. It has beenfound that the average rotation rate at a latitude of 40° is close to the standard speed at the beginning(12.75°/day) and in the first phase of maximum development (13°/day); it is lower in the second phase ofmaximum development (11.7°/day) and at the end of its existence (12.5°/day). A slight increase in velocity atthe final stage is associated with the restructuring of the coronal hole. According to modern theories, the rotationof the solar corona reflects the rotation of the subphotospheric layers. The higher layers of the coronareflect the rotation of the deeper layers of the Sun. The results obtained in our work show that the rotationrate of a giant coronal hole in the maximum phase of its development is greater than the rotation rate of thesolar disk. Perhaps this indicates that coronal holes can be associated with deep solar layers through the configurationof the global magnetic field and that the source of coronal hole formation is deeper than the sourceof the background field.
Solar Activity Index for the Critical Frequency of the E Layer
Authors: Deminov M. G. , Badin V. I. , Deminov R. G. , Nepomnyashchaya E. V.
Published: April 2024

The index P = (F1 + F81)/2 is the optimal solar activity index for the critical frequency of the E layer, foE, where F1 and F81 are the flux of radio emission from the Sun at a wavelength of 10.7 cm on a given day and the 81-day average value of this flux centered on a given day. Therefore, to calculate F81 on a given day, knowledge of F1 is needed not only on this and previous days, but also 40 days in advance. Instead of index F81, in problems on short-term forecasting of this index, it is possible to use F(27, 81), the weighted average solar activity index with a characteristic time of 27 days for the current and previous 80 days. Therefore, to calculate F(27, 81), knowledge of F1 on this and previous days suffices. This paper presents the first estimates of the effectiveness of such a replacement for foE. For this, changes in the accuracy of calculating foE were analyzed when index P is replaced by P * = (F1 + F(27, 81))/2 in empirical models constructed from foE data of ionospheric stations in the daytime at middle and subauroral latitudes for 1959–1995. It turns out that the P and P * indices are almost equivalent for calculating foE based on the empirical models constructed at these latitudes: the difference in the coefficients of variation for foE does not exceed 0.3% in each season at different solar cycle phases. Therefore, P * can be recommended for use in short-term foE forecasting problems, since it is based on indices F1 for the current and previous days, as opposed to index P, which requires a forecast 40 days in advance to calculate F1.
Latituditual Structure of Dayside Polar Cusp Precipitation
Authors: Vorobjev V. G. , Yagodkina O. I. , Antonova E. E. , Kirpichev I. P.
Published: April 2024

The results of observations of low-altitude spacecraft crossing the daytime sector of the auroral zone and of high-apogee spacecraft in the equatorial plane of the magnetosphere were analyzed in order to identify the main processes leading to the formation of dayside polar cusps. Observations from the DMSP F7 spacecraft were used to analyze the latitudinal characteristics of ion precipitation in the cusp region and to study the latitudinal profile of ion pressure in the cusp depending on the IMF parameters. A significant difference was found in identifying the cusp boundaries using an automated data processing system and direct analysis of spacecraft observations. It is shown that for small negative values of the Bz-component of the IMF (〈Bz〉 = –3.0 nT), an ordinary feature of the cusp is the latitudinal profile of the ion pressure (Pi) with a width of ~1° of latitude with two maxima, one of which is located in the equatorward and the other in the poleward of the cusp. For large negative Bz values (–6, –8 nT), the polar maximum in the latitudinal profile Pi disappears; only the equatorial maximum remains, the Pi level at the maximum increases, and the width of the cusp decreases to ~0.7°. For Bz IMF 0, the most characteristic is the Pi profile with a maximum ion pressure in the polar part of the cusp. The cusp for Bz 0 is located at higher latitudes than for Bz 0, and its average latitudinal width increase to ~1.4° of latitude. In the prenoon sector MLT, the most typical for periods with a large negative By-component of the IMF (〈By〉 = –6.3 nT, 〈Bz〉 = –1.7 nT) is a cusp with a width of ~1.4° of latitude with a flat top in the latitudinal Pi profile. Comparison of the pressure distributions observed at low heights with data from high-apogee satellites confirmed the possibility of describing the formation of the cusp as a diamagnetic cavity and using observations in the cusp to determine the ion pressure in the magnetosheath.
Correspondence between Cosmic-Dust-Enriched Sediment Horizons and Geomagnetic Field Excursions
Authors: Kurazhkovskii A. Yu. , Tselmovich V. A. , Kurazhkovskaya N. A.
Published: April 2024

The relationship between spikes in cosmic dust fluxes onto the Earth’s surface (mainly represented by native metal particles) and the behavior of the polarity of the main geomagnetic field has been studied. For this, a search was carried out for horizons of paleodeposits with a high concentration of cosmic dust (exceeding the background concentration by more than an order of magnitude). Such increased concentrations of cosmic dust particles were found in peat deposits corresponding to the Etrussia excursion (2.5–3 ka), as well as in ancient Cretaceous and Paleogene marine deposits. In total, we discovered five horizons with a thickness up to 1 m hosting a high concentration of cosmic dust. Measurements of the paleo‒and petromagnetic parameters of samples selected based on the thickness of sedimentary strata showed that the beginning of accumulation of these horizons coincided with geomagnetic field excursions. In this case, sediment enrichment in dust particles could have lasted somewhat longer than a geomagnetic field excursion. Evidence was obtained that Earth collisions with dense fluxes of cosmic dust could have coincided with short-term disturbances in the polarity of the geomagnetic field, but this had no lasting effect on the geodynamo.
Long-Term Microwave Observations of Middle Atmospheric Ozone
in Apatity during Three Winters
Authors: Kulikov Yu. Yu. , Andriyanov A. F. , Demin V. I. , Demkin V. M. , Kirillov A. S. , Ryskin V. G. , Shishaev V. A.
Published: April 2024

The results of ground-based microwave observations of ozone in the middle atmosphere in Apatity(67° N, 33° E) during three winters (2017–2018, 2018–2019 and 2019–2020) are presented. Long-term ozoneobservations were carried out during the period of minimum solar activity for cycles 24 and 25. A mobilemicrowave spectrometer with an operating frequency of 110.8 GHz was used in the measurements, whichallows tracking the behavior of ozone in the middle atmosphere with a 15-minute time resolution. The microwaveozone data from ground-based measurements are compared with the MLS/Aura onboard data. Groundand airborne data are compared with the data of contact measurements with ozonesondes at Sodankyla st.(67° N, 27° E). In addition, MLS/Aura data from mid-atmospheric temperature soundings are used to interpretperturbations in the ozone layer associated with sudden stratospheric warmings. A significant influencesudden stratospheric warming on the ozone vertical distribution at altitudes of 22–60 km was found. At thesame time, the scale of mesospheric ozone variability (60 km) over Apatity is comparable or exceeds theknown model calculations for assessing the impact of solar proton events and auroral electron precipitationon the ozone of the polar regions.
Statistical Analysis of the Critical Frequency foF2 Dependence
on Various Solar Activity Indices
Authors: Danilov A. D. , Berbeneva N. A.
Published: April 2024

A description of the ionospheric F2-layer critical frequency foF2 dependence on solar activity byvarious indices (proxies) has been analyzed. The results of the vertical ionospheric sounding at the Juliusruhstation during 2 winter months (January and February), 2 equinox months (March and October), and a summermonth (June) are considered. Five solar proxies: Ly-α, MgII, Rz, F30, and F10.7 have been analyzed.The changes in foF2 are compared to the corresponding changes in 1957–1980. The determination coefficientR2 according to the Fisher F-test is used as a measure of the quality of the description of the foF2 dependenceon SA by each of the proxies. It has been found that a well-pronounced diurnal variation in the R2 valueis observed in winter months: this is higher at the near-noon hours than at night. In other words, all indicesdescribe the foF2 behavior better in the daytime than at night. A well-pronounced diurnal variation in R2 isalso observed for four proxies in the equinoctial months, whereas that variation is pronounced much less forRz: a strong scatter of the R2 values is seen. A diurnal variation in the R2 is absent completely in June: jumpsfrom one hour to another are observed. This analysis allows us to conclude that the most reliable SA proxiesfor description of the foF2 dependence on SA at all LT hours are MgII, F30, and Ly-α.
F-Region Variations Prior to Magnetic Storms (a Review)
Authors: Danilov A. D. , Konstantinova A. V.
Published: April 2024

The paper presents a review of variations in ionospheric parameters in the prestorm period obtained from an analysis of particular magnetic storms (case studies). It is demonstrated that, as a result of such analysis, deviations of these parameters (primarily, foF2 and TEC) are often observed on the days preceding the storm commencement (SC). Many authors pay attention to these facts and discuss their relation to space weather parameters, season, local time, and spatial distribution, and even offer suggestions on possible mechanisms of their formation. It is demonstrated that the number of such publications increased substantially in the preceding 4–5 years. It is emphasized that changes in the ionospheric state on prestorm days are detected not only in the “classical” parameters (foF2 and TEC), but also in other ionospheric characteristics. Publications dedicated directly to the problem of ionospheric precursors, their relation to space weather, and their possible role in forecasting coming magnetic storm are considered in detail.
Using Carbon Quantum Dots for the Determination of Aminoglycoside Antibiotics by Fluorescence Polarization Immunoassay
Authors: Larina M. Yu. , Farafonova O. V. , Eremin S. A. , Ermolayeva T. N.
Published: April 2024

Conditions are studied for the synthesis of carbon quantum dots (CQD) exhibiting green fluorescence by the ultrasonic treatment of multilayered carbon nanotubes in a mixture HNO3 with H2SO4 (CQD-1) and by the microwave decomposition of 9,10-dinitroanthracene in ethanol (CQD-2). The sizes of COD are estimated by atomic force microscopy, and their optical properties, by spectrophotometry and fluorescence spectrometry. Infrared spectrometry was used to identify active functional groups on the CQD surface, participating in the formation of stable bonds in the synthesis of tracers. A possibility of using CQD as labels in fluorescence polarization immunoassay (FPIA) is shown. Procedures are developed for determining aminoglycoside antibiotics gentamycin, streptomycin, and amikacin by FPIA using a TDx-analyzer (Abbott Diagnostics, United States); their performance characteristics are presented. The limit of detection is (ng/mL) 20, 10, and 3, and the analytical range (µg/mL) is 0.05–3.00, 0.02–6.00, and 0.01–3.00 for gentamycin, streptomycin, and amikacin respectively. The procedures are tested in the determination of gentamycin, streptomycin, and amikacin in dairy products.
Various labels, most often enzyme or fluorescent, are used to
Identification and Authentication of Milk Using Digital Colormetry of Indicator Test Systems, Smartphone, and Chemometric Analysis
Authors: Amelin V. G. , Shogah Z. A. Ch. , Bol’shakov D. S. , Tret’yakov A. V.
Published: April 2024

A simple and an available method is proposed for the identification and authentication of milk using a test device, a smartphone, and chemometric analysis. For the identification by the region of origin and the species of milk (cow, goat, sheep, etc.) and authentication (authenticity, falsification of milk), acid-base indicator papers and test papers are used to determine the total hardness and total alkalinity of water and chloride and sulfate ions. Two indicator systems are proposed. In the first test system, 16 indicator zones are used, of which 12 zones are acid-base indicators with a color change in the pH range of 3–9, and 4 are indicator zones, the color change of which depends on the concentration of calcium ions and chloride, sulfate, carbonate, and hydrocarbonate ions. The second test system uses fluorescent indicators, as well as the intrinsic fluorescence of milk on cellulose paper and a thin silica layer. In this case, the indicator zones of the matrix are irradiated with monochromatic ultraviolet light (365 nm) after applying milk samples to them. A device and a method for measuring the colorimetric characteristics of test systems using a smartphone are proposed. The data array (the sum of the RGB channel values) is processed using the XLSTAT software. The use of chemometric analysis made it possible to establish the authenticity of milk, identify it by the region of origin, and reveal facts of milk falsification by dilution with water, the use of vegetable fats, and emulsification with surfactants. The manufacturers of pasteurized milk were identified and a possibility of determining its fat content by the data array of RGB colorimetric parameters is proved
Benzofuran Spiropyrans as Analytical Reagents for Low-Molecular-Weight Aminothiols
Authors: Shcherbatykh A. A. , Askalepova O. I. , Bulanov A. O. , Shcherbakov I. N. , Nguyen S. T.
Published: April 2024

The problem of determining biologically active low-molecular-weight aminothiols, such as cysteine and glutathione, requires the development of new methods and analytical reagents. Among the latter substances, a group of spiropyrans can be distinguished, which are photochromic organic substances reaching an equilibrium between their cyclic and open forms in solutions. We consider a possibility of using benzofuran spiropyrans as analytical reagents for aminothiols and studied the effect of various substituents in their structure on the change in optical properties in the presence of cysteine and glutathione. An equilibrium in solutions of benzofuran spiropyrans bearing a hydroxyl group in position 7 shifts in the presence of analytes towards the formation of a colored open form. The considered spiropyrans were used to create a simple, selective, and sensitive procedure for the spectrophotometric and kinetic determination of cysteine and glutathione in vitro.
Chromatographic Determination of Ibuprofen in Rhodococcus Culture Media and Kinetic Modeling of Its Biodegradation Process
Authors: Vikhareva E. V. , Selyaninov A. A. , Bazhutin G. A. , Tyumina E. A.
Published: April 2024

The conditions for the chromatographic determination of ibuprofen in culture media of Rhodococcus spp. by reversed-phase HPLC are chosen. The specificity, linearity, and accuracy of the developed procedure are confirmed by the validation procedure, which allows its use for a reliable assessment of ibuprofen concentration in the process of bacterial degradation. With the use of kinetic modeling, a forecast is made for changes in the concentration of ibuprofen; the half-life period, the end time of the biodegradation process, and its reproducibility are determined.
Evaluation of a Possibility of the Application of “Electronic Nose” to Monitoring Deviations in the Functional Obesity of Children in Hospital Conditions: Observations of Changes during Treatment
Authors: Kuchmenko T. A. , Dorovskaya E. S. , Menzhulina D. A. , Chubarov T. V. , Murakhovskii I. A.
Published: April 2024

This work is a continuation of a study on the use of chemical gas sensors and a portable “electronic nose” for diagnosing obesity and related pathologies in children in a hospital. Using a portable Bio-8 device, 330 volatile skin compound profiles were measured in the forearm region on an empty stomach in various states of children with various diseases during inpatient examinations and treatment in the endocrinology department. Monitoring changes in the profile of volatile skin compounds during the period of hospital stay in obese children made it possible to identify priority metabolic disorders in multiple pathological disorders and diagnoses by a characteristic set of chemical biomerkers of processes, reliably detected in skin secretions on the right forearm. Multiparametric data of the “electronic nose” were processed by principal component analysis to assess ranking of the results into the groups “Normal” and “Obesity with a risk of the development of type 2 diabetes mellitus (DM)”. Based on the highly informative parameters of the sensor array, changes in the chemical composition of the skin gas profile on the right forearm during the period of patients’ stay in the hospital and the effectiveness of standard approaches in each specific case were evaluated, and the personalization of treatment was thus increased. Simple calculated parameters and a method for assessing lipid and carbohydrate metabolism disorders based on the signals of eight sensors above the skin measured for 200 s without sampling were proposed. The sensitivity of the method for monitoring changes in the metabolome in a hospital is at least 80%. Specificity for lipid metabolism disorders is 100%; for type 1 diabetes, 100%; and for mixed pathologies varies from 70 to 85%.
Automated Liquid–Liquid Microextraction of Fluoroquinolones for Their Subsequent Chromatographic Determination
Authors: Timofeeva I. I. , Barbayanov K. A. , Bulatov A. V.
Published: April 2024

An automated method is developed for dispersive liquid–liquid microextraction of fluoroquinolone antibiotics based on the principles of stepwise injection analysis. The method involves the dispersion of the extractant by the gas phase, formed in situ in the extraction chamber of the flow analyzer. A deep eutectic solvent based on a terpenoid and a mixture of hydrophilic and hydrophobic carboxylic acids is studied as an extractant for the isolation and preconcentration of fluoroquinolones, and a possibility of its use is substantiated. Hydrophilic carboxylic acid in the composition of the extractant acts as a proton donor for the formation of a carbon dioxide dispersant in the presence of sodium carbonate dissolved in the aqueous phase. A possibility of combining the developed method with high-performance liquid chromatography with fluorimetric detection is shown on an example of the determination of fluoroquinolones in wastewaters. The limits of detection (3σ) for ofloxacin, fleroxacin, and norfloxacin were 0.3 µg/L.
Behavior and Fractionation of Low-Volatile Impurities in a DC Arc in the Analysis of Zirconium by Atomic Emission Spectrometry
Authors: Zolotareva N. I. , Grazhulene S. S.
Published: April 2024

We studied the effect of chemically active fluorine-containing additives AlF3, BaF2, and ZnF2 on the character of evaporation of some low-volatile elements from a refractory matrix in the crater of a DC arc electrode in the analysis of zirconium by atomic emission spectrometry. The additives cause the formation of volatile fluorides of low-volatile elements and their fractional evaporation with respect to the base element evaporation. Impurity fluorides rapidly and completely evaporate during the first 30 s of arcing, and only after that the intensive evaporation of the base begins. Such fractionation increases significantly the intensity of the spectral lines of impurities, decreases the background intensity, and, consequently, improves the limits of determination of low-volatile elements in zirconium oxide. Zinc fluoride is the most effective of the studied additives. Using zinc fluoride, we lowered the limits of determination of low-volatile elements by two orders of magnitude compared to the limits of determination in zirconium oxide without additives and improved the reproducibility of the results of determinations.
Chromatographic Determination of Diflubenzuron Residues in Agricultural Plant Matrices
Authors: Alekseev E. Yu. , Chermenskaya T. D.
Published: April 2024

The article deals with the development of a method for the determination of diflubenzuron in agricultural products using HPLC with a diode array detector. The samples were extracted with acetonitrile, and then purified by solid-phase extraction using C18E and PSA adsorbents and a Diapak C cartridge. The developed method was tested on the green mass of plants, potato tubers, corn grain, soybeans, sunflower seeds, rapeseed, and vegetable oil in the concentration range from 0.025 to 0.25 mg/kg. The average values of recovery were 81–91% with an error of 1.3–2.3%.
Analysis of Small-Mass Biological Samples by ICP MS Using Microwave Acid Digestion of Several Samples in the Common Atmosphere of a Standard Autoclave
Authors: Kolotov V. P. , Dogadkin D. N. , Zaichik V. E. , Shirokova V. I. , Dogadkin N. N.
Published: April 2024

To expand the available tools for the analysis of samples of biological and plant origin of small mass (10–20 mg) using ICP MS, we developed a construction made of three compact teflon reaction minivessels (inserts) of an internal volume of 3 mL, placed in a standard autoclave (EasyPrep) of a volume of 100 cm3 of a MARS-5 microwave system (CEM). The acid digestion of samples in reaction minivessels requires no more than 1.5 mL of highly pure acids. The digestion of samples proceeds in the common gas atmosphere of a standard autoclave filled with a needed volume of acids of pure for analysis grade. The method was tested on reference materials of plants and biological sample. The results obtained are in agreement with the certified values. The developed method ensures the decrease of the detection limits and obtaining new data on the concentrations of B, Ga, Y, Nb, Tl, Bi, and a number of rare-earth elements in the reference materials.
Use of Magnetic Carbon Nanocomposites in the Formation of a Recognition Layer of a Piezoelectric Immunosensor for the Determination of Penicillin G
Authors: Bizina E. V. , Farafonova O. V. , Zolotareva N. I. , Grazhulene S. S. , Ermolaeva T. N.
Published: April 2024

Conditions for the formation of a recognition layer of a piezoelectric immunosensor based on magnetic carbon nanocomposites (MCNCs) under the action of an external magnetic field are studied. The effects of the size and number of magnetic nanoparticles (MNPs) in the composite on the analytical characteristics of the gravimetric immunosensor are revealed. Scanning electron microscopy is used to determine the average sizes of Fe3O4 magnetic nanoparticles synthesized by coprecipitation. It is noted that the minimum weight and stability of the recognition layer were observed for the nanocomposite obtained at a ratio of carbon nanotubes and MNPs with an average diameter of 22 nm equal to 3 : 1. The formation of peptide bonds between the MCNCs and a penicillin G conjugate was established by IR spectrometry. It was shown that the use of magnetic carbon nanocomposites in the formation of a recognition layer makes it possible to significantly simplify the procedure for preparing a piezoelectric sensor for analysis and reduce its duration from 24 to 1.5 h. The range of the determined antibiotic concentrations is 1–450 ng/mL, the limit of detection is 0.5 ng/mL.
Complex Coulometric Evaluation of the Antioxidant Properties of Beer
Authors: Matveeva S. Yu. , Ziyatdinova G. K.
Published: April 2024

The reactivity of coulometric titrants (bromine, iodine, and hexacyanoferrate(III) ions) with respect to the antioxidants (AOs) of beer is evaluated. It is shown that electrogenerated iodine interacts with ascorbic acid and sulfur-containing compounds, but does not oxidize phenolic AOs. The stoichiometric coefficients of reactions of phenolic AOs with electrogenerated bromine and hexacyanoferrate(III) ions are found. A comprehensive assessment of the antioxidant properties of beer is carried out through overall antioxidant parameters (total antioxidant capacity (TAC) according to the reaction with electrogenerated bromine, ferric reducing power (FRP) according to the reaction with electrogenerated hexacyanoferrate(III) ions, and oxidation by). Sixteen samples, differing in the type of fermentation, variety, and style, are considered. A statistically significant difference between the parameters for individual samples is shown. The TAC and FRP of beer correlate with the total concentration of phenolic compounds and antioxidant activity (r = 0.7175–0.8703 at rcrit = 0.4973), which confirms the correctness of the results obtained using coulometric titration. Differences in the overall antioxidant parameters of the top-fermented and bottom-fermented beers, as well as filtered and unfiltered light and dark beers, are statistically insignificant (p = 0.10–0.82). The change in the overall antioxidant parameters of beer during storage in air is evaluated.
Capillary Electrophoresis in Assessing the Quality and Safety of Foods
Authors: Bolshakov D. S. , Amelin V. G.
Published: April 2024

This review is dedicated to the application of capillary electrophoresis to assess the quality and safety of food products.
Cathode Nanophosphors
Authors: Yagov V. V.
Published: April 2024

High-current cathodic pulses on an aluminum electrode in solutions containing sufficiently high concentrations of Mg, Ca, Sr, Al, Sc, Y, or La nitrates in a mixture with H3BO3, HF, H3PO4, or H4P2O7 are accompanied by an intense intrinsic luminescence of a number of heavy metals, the ions of which are captured by salt nanofilms and luminescence under the action of hot electrons when are in an environment characteristic of crystal phosphors. The effect of the cathode nanophosphor (CNP) was found in more than 100 systems; photographs are presented for most of the systems. Ga, In, Tl, Ge, Sn, Pb, Mn, Cu, Ag, Cd, Ce, Tb, and Zr ions were activators. The effect of matrix composition on the spectral and kinetic characteristics of the CNP was shown on several examples; a qualitative description of the phenomenon is given, and the prospects for its application to chemical analysis are considered.
A Voltammetric Sensor Based on Aluminophosphate Zeolite and a Composite of Betulinic Acid with a Chitosan Polyelectrolyte Complex for the Identification and Determination of Naproxen Enantiomers
Authors: Zilberg R. A. , Maistrenko V. N. , Teres Yu. V. , Vakulin I. V. , Bulysheva E. O. , Seluyanova A. A.
Published: April 2024

A voltammetric sensor was developed based on a glassy carbon electrode with aluminophosphate zeolite finely dispersed on its surface, modified with a polyelectrolyte complex of chitosan with succinyl chitosan and betulinic acid, for the selective detection and determination of naproxen enantiomers. The electrochemical and analytical characteristics of the sensor were studied, and the effective electrode surface area (A = 9.8 ± 0.5 mm2) and charge transfer resistance (Ret = 649.9 ± 0.4 Ω) were calculated. In determining naproxen enantiomers, calibration characteristics are linear in the range from 2.5 × 10–5 to 1 × 10–3 M with limits of detection of 1.1 × 10–7 and 1.5 × 10–7 M and limits of quantification of 3.6 × 10–7 and 4.9 × 10–7 M for R- and S-naproxen, respectively. The sensor is more sensitive to R-naproxen (∆Ep = 60 mV, ipR/ipS = 1.40). The proposed sensor was used to recognize and determine naproxen enantiomers in human urine and plasma samples. Statistical evaluation of the results by the standard addition method showed that there was no systematic error.
S,N-Containing Sorbents for Analyzing Rare Earth Element Compounds by Arc Atomic Emission Spectrometry
Authors: Arkhipenko A. A. , Doronina M. S. , Korotkova N. A. , Shevchenko A. S. , Baranovskaya V. B. , Dalnova Yu. S.
Published: April 2024

A possibility of using S,N-containing sorbents for the analysis of materials based on rare earth element compounds with the determination of impurities in the sorption concentrate by arc atomic emission spectrometry is studied. The properties of S,N-containing sorbents in aqueous solutions and various rare earth matrices are studied. A methodological approach to the sorption preconcentration of impurities in REE-based materials followed by a direct analysis of the sorption concentrate by arc atomic emission spectrometry is described. The results of the development of a spectrochemical method for determining impurities in rare earth element materials are presented, and performance characteristics are evaluated.
Tunable Diode Lasers for Analytics and Diagnostics
Authors: Bolshov M. A. , Kuritsyn Yu. A. , Liger V. V. , Mironenko V. R. , Ponurovskii Ya. Ya.
Published: April 2024

Continuous-wave diode lasers (DLs) with tunable emission wavelengths have become extensively used in various fields of analytical spectroscopy and diagnostics. Working in the near and mid-IR spectral region, tunable diode lasers are particularly effective in detecting simple molecules, making them invaluable for environmental monitoring, industrial process control, and diagnostics of subsonic and supersonic gas flows. However, the lack of commercial diode lasers operating in the spectral region shorter than 400 nm has restricted their applicability to elemental analysis, as many resonance lines of free atoms of elements lie in the region 250–400 nm. This review aims to highlight various applications of continuous diode lasers, which are lesser-known to analytical chemists. We briefly overview their main characteristics and discuss their advantages, enabling their successful implementation in traditional analytical spectroscopy tasks, as well as for diagnosing parameters of remote gas objects, including combustion processes in mixing gas flows.
Institute of Chemistry, Chernyshevsky Saratov State University
Authors: Makhova T. M. , Arzhanukhina A. I. , Doronin S. Yu.
Published: April 2024

New test tools made of nanofibers based on polyamide-6 (PA-6) for the sorption preconcentration of some phenols as their azo derivatives followed by colorimetric determination are obtained. Approaches to the derivatization of phenol and chlorine derivatives by azo coupling with 4-nitrophenyldiazonium and oxidative condensation with 4-aminoantipyrine for improving the sorption characteristics of the studied phenols are proposed. The efficiency of the two derivatization methods is compared. The sorption kinetics of phenol and 2-chlorophenol derivatives and the effect of pH on the nature of their sorption are studied. The features of the sorption of phenol derivatives on nonwoven materials and the corresponding sorption isotherms are interpreted. Examples of the quantitative assessment of the concentration of phenols in aqueous media by the mathematical processing of digital images of the colored areas of test tools are presented. It is shown that the proposed methods can be used for the determination of phenol and 2-chlorophenol with the preconcentration of their derivatives on a PA-6 nanofiber in the range 0.2–1.0 μM (≈0.02–0.09 mg/L for phenol, ≈0.03–0.13 mg/L for 2-chlorophenol) with an error of colorimetric determination of no more than 20% (MAChshld phenol is 0.001 mg/L for the amount of volatile phenols in water bodies, provided that water is disinfected with chlorine; in other cases, the MAC is 0.1 mg/L).
X-Ray Fluorescence Spectrometry: Current Status and Prospects of Development
Authors: Revenko A. G. , Pashkova G. V.
Published: April 2024

This review covers characteristics and potential applications of various versions of the X-ray fluorescence (XRF) spectrometry for analyzing both liquid and solid samples. Particular emphasis is given to research published within the past decade, as information on XRF’s previous applications can be found in earlier reviews and monographs. The results of experiments on determining fundamental atomic parameters, such as mass absorption coefficients, fluorescence yields, transition probabilities for the emission of specific lines of elements, and nonradiative transition probabilities. Additionally, the review addresses the capabilities of newly designed models of XRF spectrometers developed in recent years. The application of total reflection X-ray fluorescence spectrometry for diverse samples is examined in greater detail. Furthermore, the document presents data on the utilization of XRF in investigating nanoparticles of some typical materials. These particles exhibit qualitatively novel properties and have become a focal point of nanotechnology, an area rapidly developing in the last few decades.
Assessment of Radioecologically Relevant Radionuclides 14C, 99Tc, and 129I in Vitrified High-Level Nuclear Wastes from Spent Fuel Reprocessing
Authors: Chukhlantseva E. V. , Stepanova O. V. , Dichenko O. Yu. , Zaitseva T. A. , Dzhevello K. A. , Murashova E. L. , Tatarnikova Yu. M. , Belanova E. A. , Blokhin P. A.
Published: April 2024

A method is proposed for quantifying the specific activities of radioecologically significant radionuclides, including 14C, 99Tc, and 129I, in vitrified high-level wastes. The conditions for the separation and purification of these radionuclides from potential interfering components are optimized and the yield coefficients and purification factors are determined. The quantification of 14C entails a three-fold distillation in CO2 followed by the measurement of the 14C counting rate in the purified solution by liquid scintillation spectrometry. 129I was determined by dissolving a sample in HNO3, five-fold extraction, and the subsequent measurement of the 129I counting rate in the purified solution using liquid scintillation spectrometry. The determination of 99Тс included dissolving a sample in the presence of ClO–, double extraction-chromatographic separation of 99Тс with an adsorbent impregnated with methyltrioctylammonium nitrate, followed by the determination of its activity by inductively coupled plasma–mass spectrometry. We have applied this approach to a simulator of vitrified high-level waste, labeled with radionuclides, and achieved satisfactory results. This approach will be instrumental in the analysis of the accumulated vitrified high-level wastes at the “Mayak” Production Association (Mayak PA). The results will be important for modeling the engineering safety barriers of a deep disposal site for radioactive wastes.
Growth, X-ray Diffraction and Dielectric Characterization of Pb5WO8 Single Crystals in the PbO–WO3 System
Authors: Bush A. A. , Kozlov V. I. , Stash A. I. , Ivanov S. A.
Published: April 2024

Single crystals of the Pb5WO8 phase were grown in the PbO–WO3 system by crystallization of (1 – x)PbO·xWO3 (x = 0.15–0.20) mixed melts. Thermogravimetric, X-ray diffraction, and dielectric studies of the single crystals were carried out. The phase melts at 712°С with decomposition to PbO and a liquid. The Pb5WO8 crystal structure is monoclinic (space group P21/n, 293 K) with the unit cell parameters a = 7.4430(1) Å, b = 12.1156(2) Å, c = 10.6284(2) Å, β = 90.658(1)°. The Pb5WO8 structure is retained at 100 K; the minor alterations in unit cell parameters are associated only with thermal expansion. The Pb5WO8 structure has a pronounced layered character; it appears as an alternation of layers formed of WO6 octahedra and strongly distorted PbO4 and PbO5 polyhedra in the direction [010]. A detailed crystal-chemical analysis of the structure was carried out. An important role of the Pb lone pair in the formation of characteristic voids in the structure was noted. The temperature-dependent dielectric permittivity and dielectric loss tangent feature relaxation peaks associated with lead and oxygen vacancies in the structure.
Sodium-Stabilized Hexagonal Borophene: Structure, Stability, and Electronic and Mechanical Properties
Authors: Steglenko D. V. , Gribanova T. N. , Minyaev R. M. , Minkin V. I.
Published: April 2024

The crystalline form of sodium-doped hexagonal borophene (B2Na2) has been studied using DFT calculations. The calculations predict the dynamic stability of B2Na2 whose structure is a flat honeycomb boron sheet sandwiched between two sodium layers. According to estimated electronic and mechanical properties, B2Na2 is a rather soft material with metallic characteristics. Evaluation of thermal stability by the molecular dynamics method indicates sufficient stability of the predicted material, which makes it possible to observe it experimentally at temperatures below 200 K.