bluuebunny/crossref_metadata_2025 huggingface dataset:
Магнитно-резонансная томография в диагностике миокардитов и кардиомиопатий. Методика проведения исследования
Authors: Синицын В.Е. , Мершина Е.А. , Коробкова И.З. , Рыжкова Е.В. , Филатова Д.А.
Published: April 2024

Актуальность подготовки учебно-методического пособия по магнитно-резонансной томографии (МРТ) сердца для ординаторов и врачей-рентгенологов обусловлена возрастающей ролью метода МРТ в диагностике заболеваний сердца, в первую очередь таких, как миокардиты , кардиомиопатии и ишемическая болезнь сердца. Врачи практического здравоохранения должны быть знакомы с возможностями современных методов визуализации для решения сложных диагностических задач. Пособие разработано в соответствии с Федеральным государственным образовательным стандартом высшего образования - подготовка кадров высшей квалификации по программам ординатуры по специальности 31.08.09 «Рентгенология». Учебно-методическое пособие может быть использовано в образовательном процессе ординаторов, аспирантов, врачей-рентгенологов.
Informatsionnye tekhnologii v obrazovanii: sovremennye podkhody, organizatsionnye i pedagogicheskie trebovaniia, sredstvo razvitiia motivatsii uchebnoi deiatel'nosti
Authors: Sher Marina Leonidovna , Mironov Leonid Valerevich
Published: April 2024

Information technologies in education are a prerequisite for the modern educational process. Educational institutions within the framework of the state digitalization program are equipped with modern equipment, and teachers master them, along with their students and students. In the article, authors analyzed modern ap-proaches to the use of information technology in the educational process as a means of developing motivation for educational activities. Modern society needs creative individuals capable of introspection, independent decision-making and aware of their responsibility for the well-being and socio-economic development of the state.
Simulation of the acoustic environment in computer simulators for training operators of complex military-technical systems
Authors: Chepurnov Ilia Aleksandrovich , Zakharov Denis Aleksandrovich , Shapovalov Ivan Olegovich
Published: April 2024

The relevance of simulating the acoustic environment in computer simulators for training operators of complex military-technical systems is substantiated. The features of the human auditory analyzer and the main types of acoustic noise characteristic of the working environment of the operator of complex military-technical systems are considered. The structure of the system for simulating acoustic noise in computer simulators is described.
Evaluation of Recent Surgical Updates Regarding Diagnosis and Management of Diverticulitis
Authors:   Department of Surgery, Farwaniya Hospital, Ministry of Health Kuwait, Kuwait, F. Al-Sanea Hamad
Published: April 2024

Diverticulosis occurs when small, bulging pouches (diverticula) develop in your digestive tract. When one or more of these pouches become inflamed or infected, the condition is called diverticulitis. Diverticula are small, bulging pouches that can form in the lining of your digestive system, although it was rare before the 20th century, diverticular disease is now one of the most common health problems in the western world. It’s a group of conditions that can affect your digestive tract. The most serious type of diverticular disease is diverticulitis. It can cause uncomfortable symptoms and, in some cases, serious complications. If left untreated, these complications can cause long-term health problems. Read on to learn more about diverticulitis, including its causes, symptoms, treatment options, and how your diet might affect your risk of developing it. Objective: In this paper, our main focus was on diverticulitis and surgical intervention, and only relevant studies were discussed. Methodology: PubMed database was used for articles selection, and papers on diverticulitis were obtained and reviewed. Conclusion: Colonoscopy is best avoided in acute and uncomplicated diverticulitis. Classically, it is a surgical disease but uncomplicated cases can often be managed conservatively. Follow up of treated diverticulitis occurs after four weeks via colonoscopy, in selected cases assessing the risk of developing colonic cancer. Novel therapies are under-studied and are probable replacements for surgical intervention.
SMART CITY MANAGEMENT SYSTEM UTILIZAING MICRO-SERVICES AND IOT-BASED SYSTEMS
Authors: Nazarenko V.A , Ostroushko B.P.
Published: April 2024

Urban governance is without a doubt a very complicated activity. The city doesn't just consist of people and buildings, there are transport and road infrastructure, critical infrastructure, medical facilities, road cover, industrial equipment and many more. Besides, the city council provides a wide range of services to the public. Among them healthcare, welfare, economic and finance supply, labor, real estate management and others. Information management systems and web services are employed for digital management, while various embedded management systems are used for equipment management and surveillance. Being very complex and multilayered system, Smart City Managment solutions offer a platform that encapsulates main services for both public and for technological aspects of urban governance. The results presented in this paper are based on a study of the existing software, hardware and middleware platforms for smart city use case. The main focus is middleware platform as it serves as medium that can connect existing software and hardware solutions. In the global context of Smart city management service system all major components are broken down in the format of microservices (on the level of large enterprise distributed service). Presented Managment software suit model had been broken down into multiple software architecture abstraction layers, from hardware to end-user application. As a result, the three stages smart city service implementation roadmap had been presented. Using the Middleware platform and Web-services models, the Smart City Managment services can be implemented in any given city in porotype stage for future evaluation and full version implementation.
DETERMINATION OF THE AVAILABLE PART OF THE EARTH SURFACE TAKING INTO ACCOUNT THE LANDSCAPE AND THE WIND
Authors: Nikolayeva M. , Tereshchenko V. , Tkachenko O.
Published: April 2024

Modeling the movement of a body along a ballistic trajectory and determining the area of the Earth's surface that a given body can reach is an important task for researchers in various fields. Additional influencing factors – wind and air resistance – complicate calculations. The models are even more difficult to simulate a heterogeneous landscape where there are mountains and depressions and for which adjacent surface sectors have significant elevation differences. In view of this, the development of modeling methods in the specified field, which will be both fast and effective, remains relevant.

The purpose of the study is to describe the structure of the data and the working principles of the model for determining the reachable area of the Earth's surface for a body thrown at an angle to the horizon. The methodological basis of the research is the computer simulation method and general scientific methods.

An approach to modeling the landscape area reachable from a point by ballistic trajectories is proposed. The basis of the approach is to specify the surface in the form of a matrix, the elements of which are objects with fields of height values. A generator of discrete maps for further processing has been created. The method of calculating body launch angles optimal for reaching target points is determined. A mechanism for determining unreachable areas covered by others and a mechanism for taking into account the effect of wind on the result, which do not require long calculations, are proposed. The matrix task of the surface with height differences allows us to talk about the prospects of research - the definition of dangerous areas for the needs of various spheres of activity.
Influence of biological preparations on organic cultivation of vegetable plants
Authors: Vdovenko Serhiy , Palamarchuk Inna , Mazur Oleksandr , Mazur Olena , Havrys Ivanna
Published: April 2024

The introduction of organic technology for growing vegetable plants will help to reduce the environmental burden of pesticides and produce safe vegetable products with high yields. The purpose of the study was to investigate the effect of biological preparations on the organic cultivation of vegetable plants. Field, measuring and weighing, mathematical and statistical methods were used to determine the efficacy of the preparations. The study was conducted in 2018-2021 in different regions of Ukraine. It was established that the systemic use of biologics during the growing season of vegetable plants provided rapid growth and development, helped to increase immunity to diseases, reduced the activity of pathogenic microorganisms in the soil, and provided an increase in overall yield. The general use of biologic preparations in open ground conditions contributed to a total potato yield of 25.4 t/ha, and the complex use of preparations on Brussels sprouts forms a larger number of heads – 90 units. The Organic Balance biological product provided an increase in yield of up to 3.5 t/ha and 90% marketability of products when growing Chinese cabbage. Chemical analysis showed that the use of biologics increased the dry matter in tomato fruits by 1.03 % – in the Rio Fuego variety and 1.39% – in the Missouri variety. The yield increase in the studied varieties of asparagus beans Laura and Purpurova was 0.5 and 0.6 t/ha compared to the variants without seed inoculation. The use of biological preparations provided a higher yield in tomato plants of the Asvon variety by 2.2 t/ha, significantly reduced the content of nitrates in fruits to 50-80 mg/kg, while in the control – 110-170 mg/kg, increased the content of dry matter by 1.03 and 1.39%, depending on the variety. The gross yield of winter garlic with the use of biologics increased by 5%, and the marketability of potato tubers increased by 5%. Organic technologies would allow farmers to minimise the use of pesticides, produce environmentally friendly products, and increase yields
Effect of filter cake and bagasse ash application on selected chemical properties of acidic Nitisol
Authors: Gonfa Assefa
Published: April 2024

The rising cost of lime, traditionally used to address soil acidity and its detrimental effects on soil fertility, has prompted the exploration of organic by-products as more affordable alternatives for mitigating soil acidity, particularly for low-income farmers. Therefore, the objective of this study was to investigate effects of filter cake (FC) and bagasse ash (BA) application on soil acidity under greenhouse condition. The experiment was laid out in a completely randomised design with four replications. The FC and BA were investigated separately each with six levels (0, 20, 40, 60, 80, and 100) t/ha-1. The acidic soil was collected from Imdibir area at a depth of 0-20 cm, air dried, ground and passed through 4 mm sieve. Each pot was received 4 kg of soil with respective treatment material after they were well homogenised. The laboratory analysis revealed that the soil had an initial pH of 5.1, while filter cake and bagasse ash had pH values of 8.0 and 10.2, respectively. Application of FC increased soil pH from 5.1 to 7.3, along with improvements in organic matter, nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, and cation exchange capacity. Similarly, BA application raised pH from 5.1 to 7.4 and enhanced organic matter, nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, and cation exchange capacity. The maximum effects for both FC and BA occurred at the highest application rate (100 t/ha-1), while iron and manganese content increased with BA application but decreased as rates increased, and copper and zinc levels were positively affected by both FC and BA applications. Overall, both FC and BA applications significantly improved soil pH and nutrient content. The findings of this study can provide practical and cost-effective solutions for improving soil fertility and crop production
The effect of perceived supervisory support on organizational commitment through employee engagement in banks in Sindh Pakistan
Authors: Kazi Abdul Ghafoor , Rind Zulfiqar Ali , Kazi Shazia
Published: April 2024

Banking Industry is continuously evolving and deals with the number of employees. Employee management in this industry is a challenging task, especially in the context of employee engagement (EE) and organization commitment (OC). Perceived Supervisory Support (PSS) can help the management in improving EE and OC. HR consulting firms are increasingly helping to understand EE, OC, and PSS but academic research on these topics is still lacking, especially in emerging economies such as Pakistan. This is an explanatory study based on Social Exchange Theory (SET). It is designed to investigate the effect of PSS (independent variable) on OC (dependent variable) through EE. Survey questionnaires had been prepared and validated for the data collection. The 313 participants from five Banks participated in this study. The Structural Equation Modeling technique was used to test the hypotheses. The results showed EE mediates the relationship between PSS and OC.
Shifting paradigms: The examination of adolescent influence in Pakistani family consumer choices
Authors: Nisar Nabeel , Ghumro Touseef Hussain , Abbass Ali Raza
Published: April 2024

Within the Pakistani family structure, decision-making authority pertaining to domestic and financial affairs is vested in the patriarch. Nevertheless, as time passes, a substantial change in the interplay of forces has been noted, in which adults, in addition to their parents, exert considerable influence in the decision-making process. Furthermore, the marketer recognized this delegation of decision-making power. The initiated investigation of this phenomenon was motivated by research findings that corroborate its existence. The study's objective is to investigate the emergence of adolescent influence in Pakistani decision-making processes. By utilizing a quantitative methodology, this study investigates the increasing influence of adolescents throughout different phases of decision-making and focuses on particular aspects pertaining to product selections within the family environment. The study posits that adolescents do, in fact, exert influence over the intricate web of family decision-making, which is consistent with previous research patterns. Nonetheless, a salient observation arises: parents maintain their authority in directing comprehensive family decisions. Given the absence of previous investigations in this particular domain, this study represents an innovative endeavor that sheds light on various facets of consumer behavior within the Pakistani context.
Features of psychological resilience development in the context of contemporary psychological research
Authors: Ostapchuk Artem
Published: April 2024

This article illuminates the dynamic nature of psychological resilience development against the backdrop of contemporary societal changes. It draws attention to the necessity of integrating an individual's internal capabilities with external support factors. Based on current psychological research, it emphasizes the multifaceted components of resilience, which include self-regulation, optimism, cognitive flexibility, and the vital role of social support systems. The work summarizes the contributions of modern scholars to the field of psychological resilience, particularly highlighting valid, including relatively new, resilience assessment scales applied as effective tools for both measuring and facilitating resilience development across various societal categories. Furthermore, the article reveals aspects of resilience research that were previously underexplored, such as the need for a deeper investigation into cross-cultural dimensions, the impact of digital technologies, and the formation of comprehensive support programs tailored to the challenges of the modern world. The goal of this article is to synthesize theoretical and empirical findings, offering a generalized summary of the research overview by contemporary scientists active in the field of psychological resilience, while also identifying future directions for study and application.
This comprehensive review not only aids in a better understanding of how psychological resilience develops but also highlights unexplored aspects and opportunities for future research. By integrating findings from various sources, it provides a foundation for creating effective assistance methods that could enhance psychological resilience in individuals regardless of their age, social position, and cultural background.
The Response of the Airglow of the Mesopause Region
to Short-Term Changes in Solar Activity
Authors: Perminov V. I. , Pertsev N. N. , Dalin P. A. , Semenov V. A. , Sukhodoev V. A. , Medvedeva I. V. , Zheleznov Yu. A.
Published: April 2024

The influence of the 27-day solar oscillation on the temperature and intensity of the airglow of themesopause region based on the hourly midnight observations of the О2А(0-1) and ОН(6-2) bands at theZvenigorod Scientific Station in 2000−2021 has been studied. It is found that the response to solar activitychanges is observed in all characteristics of the atmospheric emissions both by the yearly and seasonal data.They are statistically significant for all characteristics of the atmospheric emissions in winter and only for theО2А(0-1) intensity in summer. The positive response of the molecular oxygen emission is lower in the summerthan in the winter by approximately a factor of 2. It is found that the variations in the atmospheric emissioncharacteristics are close to antiphase with a 27-day solar oscillation. At the same time, the temperatureof the emitting hydroxyl in winter undergoes oscillations with a shift by a third of the period relative to thesolar variation maximum
A Hydrodynamic Model of a Magnetized Jet Flow
in the Magnetosphere
Authors: Onishchenko O. G. , Feygin F. Z.
Published: April 2024

Abstract—A new hydrodynamic model of a quasi-stationary jet is presented. Approximation of the idealhydrodynamics of an incompressible fluid is found using an analytical solution, corresponding to a jet limitedin space, under conditions of compensation for the nonlinear effects of velocity and magnetic field in theequation of motion. An axially symmetric low-parameter model of a stationary jet was created for the boundaryconditions typical for jets in astrophysics and in laboratory modeling experiments, which makes it possibleto describe the structure of the velocity field and magnetic field.
Co-rotating Solar Wind Disturbances in Radio Sounding Data
and Local Measurements
Authors: Efimov A. I. , Smirnov V. M. , Chashei I. V. , Nabatov A. S.
Published: April 2024

In this paper, we present the results of two series of experiments on radio sounding of near-solarplasma by the signals of the Mars Express and Venus Express spacecraft in 2006 and Mars Express in 2008.The radio sounding data are compared with measurements of the proton concentration near the Earth’s orbiton the Wind satellite. This analysis shows that the general nature of the temporal dynamics of disturbancesobserved in two series of measurements is qualitatively similar. The sequence of amplifications of fluctuationsin the frequency and density of protons indicates that the observed disturbances are associated with co-rotatingregions of interaction of solar wind flows of various velocities
Refined Spatio-Temporal Model of Accelerations
of the Main Geomagnetic Field on the Earth’s Surface
and Geomagnetic Jerks
Authors: Simonyan A. O. , Ohanyan M. V.
Published: April 2024

Refined spatial spherical harmonic models of the piecewise constant field of secular geomagneticaccelerations have been constructed based on the concept of geomagnetic jerks. The data of the 189 magneticobservatories operating during the extended period of investigations have been analyzed, assuming that jerksare manifestation of sharp changes in regimes of quasi-stationary magnetohydrodynamic process of generationof geomagnetic secular variations in the high-frequency spectrum range. Qualitative and quantitativeanalyses have been carried out, showing the persistency of models of the current generation, and their consistencywith the acceleration field values obtained from direct observatory observations data. The epochs ofjerks that occurred in the extended time period were refined and it was found that on the global scale theyhave quasi-decadal repeatability, through which it is possible to estimate the time characteristics of regimesof the stationary evolution of the magnetic field of the Earth’s core. An analysis of the results of spherical harmonicmodeling using the maps of the global field of accelerations showed that the origins of all identifiedjerks are of an intraterrestrial character, which also provide the specific features of their morphological structure,as well as the degree of their distribution on the Earth’s surface
Diurnal Variations of the Statistical Characteristics of NmF2
Variability According to Ground-Based Low Latitude Ionosondes
in Geomagnetically Quiet Conditions at Low Solar Activity
Authors: Pavlov A. V. , Pavlova N. M.
Published: April 2024

The study of diurnal variations of the statistical characteristics of the day-to-day variability of theNmF2 electron number density of the F2 ionosphere layer for each month (M) of the year in geomagneticallyquiet conditions at low solar activity according to hourly measurements of the critical frequency of the F2 ionospherelayer was carried out in Huancayo and Jicamarca. We calculated the NmF2E mathematical expectation,the NmF2A arithmetic mean, the most probable NmF2MP, the NmF2MED arithmetic mean monthlymedian, standard deviations σE, σA, σMP, and σMED and coefficients of variations CVE, CVA, CVMP, andCVMED of the NmF2 value from NmF2E, NmF2A, NmF2MP, and NmF2MED, respectively. It has been foundthat the difference of NmF2MED(UT,M) from NmF2E(UT,M) does not exceed 46%, NmF2MP(UT,M) fromNmF2E(UT,M): 102% and NmF2MP(UT,M) from NmF2MED(UT,M): 85%, where UT is Universal Time.The calculated statistical parameters σE, σA, σMP, σMED, CVE, CVA, CVMP, and CVMED are the characteristicsof the NmF2 variability from one day to another day at fixed M and UT values over low-latitude Huancayoand Jicamarca ionosondes in geomagnetically quiet conditions at low solar activity. The calculations showedthat the CVE, CVMED, and CVMP coefficients vary between 18%–82%, 19%–107%, and 18%–288%, respectively,and in the majority of cases, CVE(UT,M) is less than CVMED (UT,M) and CVMP(UT,M). It was shownthat minimizing the standard deviation and the variation coefficient of NmF2 using the mathematical expectationof NmF2 provides the best description of the set of NmF2 measurements with one single NmF2 statisticalparameter under the considered conditions. The lowest CVE varies from 18% (April) to 29% (September)and the highest CVE ranges from 63% (November) to 73% (January). The average CVE value (average relativeday-to-day variability of NmF2) is highest in September (40%) and lowest in April (33%).
Features of Polar Substorms: An Analysis of Individual Events
Authors: Kleimenova N. G. , Gromova L. I. , Despirak I. V. , Malysheva L. M. , Gromov S. V. , Lyubchich A. A.
Published: April 2024

Polar substorms include substorms observed at geomagnetic latitudes above 70° MLAT in theabsence of simultaneous negative magnetic bays at lower latitudes, that is, substorms on the compressed contractedauroral oval. The general morphological features of polar substorms are considered based on theexample of individual events registered on Svalbard arch. It is shown that polar substorms, like “classical”substorms, are characterized by the formation of a substorm current wedge and a steplike movement to thepole after the onset of a substorm, generation of Pi2 geomagnetic pulsations, and an increase of the PC-indexof the polar cap before the onset of the substorm. At the same time, there are certain differences between polarsubstorms and “classical” substorms; namely, they start on more distant L-shells, develop in the region of acontracted auroral oval, occur at earlier pre-midnight hours, and generate only at low solar wind speeds andweakly disturbed geomagnetic conditions. It has been suggested that polar substorms may be a specific typeof “classical” substorms that develop in the evening sector under magnetically quiet or weakly disturbed conditionswhen the auroral oval is concracted. The source of polar substorms may also be a local intensificationof previously existing substorms in the post-midnight sector
The Depths to Lithospheric Magnetic Sources under the Baltic Shield
Authors: Filippova A. I. , Filippov S. V.
Published: April 2024

We present the results of studying the depths to lithospheric magnetic sources under the BalticShield and adjacent territories of the Russian Plate and the Scandinavian Caledonides. The depths have beencalculated from the global model of the lithospheric geomagnetic field EMAG2v3 by the centroid method.The minimum depths of the lower boundary of the lithospheric magnetically active layer (30–35 km) wereobtained under the frame of the Baltic Shield, that is, the Russian Plate, the northern and southern parts ofthe Scandinavian Caledonides, the maximum (45 km), under the Scandinavian Peninsula, in the west ofthe Svecofennian orogen and the Norrbotten craton. The rest of the territory of the Baltic Shield is characterizedby intermediate depths (38–45 km). Based on a comparison of our estimates of the depth of the lowerboundary of lithospheric magnetic sources with the currently available models of the distribution of the Mohodepth under the study area, it can be seen that for most of the Baltic Shield, the magnetically active layer of thelithosphere is located within the crust, with the exception of two areas under the Svecofennian orogen and theeastern part of the Kola Peninsula. This fact supports the hypothesis that the upper mantle has magnetic propertiesin regions where positive long-wave anomalies of the geomagnetic field are observed at satellite altitudes.The obtained results show that the western and eastern parts of the Kola Peninsula can differ not only in thevelocity structure of the crust and upper mantle, which has been previously established by various seismologicalmethods, but also in the magnetic properties of the upper mantle layer located directly under the crust.
Isolated Solar Cosmic Ray Events Caused
by Energetic Storm Particles (ESPs)
Authors: Bazilevskaya G. A. , Daibog E. I. , Logachev Yu. I.
Published: April 2024

Based on the catalogs of solar proton events for the 23rd and 24th solar cycles, events were chosenthat lacked a reliable source of particles but were accompanied by interplanetary and geomagnetic disturbances.As a rule, these events involve small proton fluxes that are detected near the Earth. All of the selectedevents occurred during the arrival of shock waves to the Earth, suggesting that they were likely caused by thearrival of energetic storm particles. It has been shown that flares accompanied by coronal mass ejections,which occurred tens of hours before the onset of the increase in particle fluxes in Earth’s orbit, could be thesource of these events. The selected events exhibited several specific features. Only one of them was accompaniedby a single shock front, while the others had two or three shock waves. The time profile of the eventsresembled a structure bounded by two shock fronts, suggesting that the shock waves likely accelerated andconfined the particles within a limited region of space.
The Influence of Corotating Regions of Interaction of the Solar Wind
on Long-Term Variations in the Intensity of Galactic Cosmic Rays
Authors: Kalinin M. S. , Krainev M. B. , Luo S. , Potgieter M. S.
Published: April 2024

An analysis of the data of spacecraft that scanned large areas of the heliosphere, as well as the resultsof magnetohydrodynamic calculations, indicates that the corotating interaction regions of solar wind (SW),which are almost always present in the low- and mid-latitude heliosphere, sometimes strongly change thelarge-scale characteristics of the heliosphere that are important for long-term variations in the intensity ofgalactic cosmic rays (GCRs). In particular, for Carrington rotation no. 2066 (January–February 2008), theseregions enhance magnetic fields in the inner (r 3–5 AU) heliosphere and weaken them in the middle andfar heliosphere, as well as significantly changing the polarity distribution of heliospheric magnetic fields. Theassumption is made that in this situation the influence of the corotating interaction regions should lead to anincrease in the GCR intensity in many regions of the heliosphere. This paper discusses the process of changingthe polarity distribution of heliospheric magnetic fields due to the interaction of SW streams for Carringtonrotation no. 2066 of different speeds, the simple model of the heliospheric magnetic field without aninteraction between the SW streams of different speeds, as well as the results of numerical two-dimensionalfinite-difference calculations of longitude-averaged GCR intensity with the use of this model in comparisonwith a three-dimensional Monte Carlo calculation based on three-dimensional magnetohydrodynamic simulationof the heliosphere.
Hydrolytic Stability of Unsubstituted Hydrazones of Aromatic Carbonyl Compounds in Reversed-Phase HPLC
Authors: Deruish A. , Karakashev G. V. , Ukolov A. I. , Zenkevich I. G.
Published: April 2024

Unsubstituted hydrazones RR′C=NNH2 are unstable during gas chromatographic separation. Testing of their resistance to hydrolysis under reversed-phase HPLC showed that aromatic ketone hydrazones are stable. In contrast, aldehyde hydrazones are only stable in neutral methanol–water systems (in the absence of acidic modifiers). In acetonitrile–water systems containing 0.1% of formic acid, only aromatic ketone hydrazones are stable, while aldehyde derivatives are completely hydrolyzed. This difference in stability must be taken into account in determining other compounds of these classes. To detect the hydrolysis of analytes, we compared the retention indices of the initial carbonyl compounds and hydrazones at different volume ratios of organic modifiers and aqueous phases and different pH values of the eluent, the relative absorbance values of the characterized components A(254/220) = A(254)/A(220), and the chromatography–mass spectrometric data.
Analytical Capabilities of the Determination of Carbohydrates by Chromatographic and Electrophoretic Methods
Authors: Kartsova L. A. , Maliushevska A. V. , Kolobova E. A.
Published: April 2024

The review discusses the advantages and limitations of chromatographic and electrophoretic approaches to the determination of neutral carbohydrates in various samples with complex matrices, the possibility of implementing a variety of liquid chromatography and capillary electrophoresis modes (in zone and micellar versions), and their combinations with various derivatization, detection, and sample preparation techniques. Conditions for the indirect detection of sugars upon the introduction of various absorbing additives into a mobile phase or supporting electrolyte, ligand-exchange capillary electrophoresis, and intracapillary complexation and the determination of carbohydrates by anion-exchange and hydrophilic chromatography are discussed.
Determination of 6-Nitro-7-(4'-Nitrophenyl)-5-Ethyl-4,7-Dihydropyrazolo[1,5-a]Pyrimidine-3-Carboxylate as a Potential Antitumor Agent by Voltammetry
Authors: Mozharovskaia P. N. , Ivoilova A. V. , Terekhova A. A. , Tsmokalyuk A. N. , Ivanova A. V. , Kozitsina A. N. , Rusinov V. L.
Published: April 2024

6-Nitro-7-(4'-nitrophenyl)-5-ethyl-4,7-dihydropyrazolo[1,5-a]pyrimidine-3-carboxylate (1) is one of promising antitumor compounds exhibiting biological activity against type 2 casein kinase, which is currently considered as a promising target in chemotherapy. Using the method of cyclic voltammetry, it was shown that the electrochemical activity of compound 1 in a mixed solution of Tris-HCl and ethanol (1 : 1) at pH 7.5 on a glassy-carbon electrode is due to the electrochemical reduction of the nitro group conjugated with the phenyl ring. A method was developed for the determination of compound 1 by direct cathodic square-wave voltammetry. The linearity region of the corresponding calibration curve obtained in a solution of a mixture of Tris-HCl and ethanol (1 : 1) at pH 7.5 is 5–500 mg/L (R2 = 0.988), the limit of detection is 0.8 mg/L, the limit of quantification is 2.4 mg/L. The accuracy of the developed procedure is close to 100%, the relative standard deviation is 1.4%.
A Thin Layer Method for the LA-ICP-MS Analysis of Trace Element Concentrates
Authors: Medvedev N. S. , Kurbatova V. D. , Saprykin A. I.
Published: April 2024

A method is proposed for the analysis of trace element concentrates by a thin layer method in combination with inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA). Trace elements concentrates were evaporated on preliminarily prepared areas of a high-purity silicon substrate, after which an LA-ICP-MS analysis was performed. The influence of the LA parameters and the conditions for recording the spectra on the signal of the analytes and the substrate material was studied. The analytical capabilities of the thin layer method in combination with LA-ICP-MS for the analysis of high-purity substances with the preconcentration of trace elements were evaluated. Using an analysis of high-purity nitric acid as an example, it was shown that the limits of detection for analytes in the LA-ICP-MS analysis of trace element concentrates using the thin layer method are in the range from n × 10–11 to n × 10–8 wt %. Thus, the development of combined procedures of analysis, including the preconcentration of trace elements and an analysis of concentrates by LA-ICP-MS, makes it possible to reduce the limits of detection for most analytes by one order of magnitude compared to instrumental ICP-MS analysis.
Novel Mixed-Mode Adsorbents for HPLC Based on Different Substrates Modified with Eremomycin
Authors: Chikurova N. Yu. , Prosuntsova D. S. , Stavrianidi A. N. , Staroverov S. M. , Ananieva I. A. , Smolenkov A. D. , Chernobrovkina A. V.
Published: April 2024

New adsorbents based on silica and polystyrene–divinylbenzene (PS–DVB) for hydrophilic interaction liquid chromatography (HILIC) with eremomycin in functional layers were obtained. The chromatographic properties of the new adsorbents were assessed using the Tanaka test for hydrophilic stationary phases and by studying the retention of substances of various classes in HILIC, chiral, and reversed-phase chromatography modes. It was shown that the use of eremomycin to create functional layers leads to an increase in the hydrophilicity of the adsorbents on different types of substrates and ensures the shielding of their charge. Eleven nitrogenous bases, nucleosides with an efficiency of up to 25 000 tp/m, or seven vitamins with an efficiency of up to 40 000 tp/m can be separated on a modified sorbent based on aminopropyl silica, and three different HPLC modes can be implemented on the sorbent with eremomycin based on PS–DVB.
Comparative Analysis of Chemical Compositions of Mentha L. Plant Extracts by Gas Chromatography–Mass Spectrometry after Hydrodistillation and Subcritical Extraction
Authors: Nazarova D. V. , Temerdashev Z. A. , Vinitskaya E. A. , Kiseleva N. V. , Nagalevskii M. V.
Published: April 2024

The results of a study of the composition of essential oil and extracts obtained by hydrodistillation and subcritical extraction from plants of the genus Mentha L. are presented. The test samples were peppermint (Mentha piperita L.) and horsemint (Mentha longifolia L.). Gas chromatography–mass spectrometry was used to identify and compare the component composition of essential oils and extracts from Mentha L. plants. The composition of the essential oil of horsemint differs from the essential oil of peppermint by the high concentration of linalool and the absence of pulegone and piperitone. The component composition of the extracts of peppermint and horsemint, obtained under conditions of subcritical extraction with water and acetone, was studied. The concentration of monoterpenes, sesquiterpenes, and esters increased in the transition from the essential oil to the acetone subcritical extract of both types of mint. In the water extract of peppermint, there were practically no sesquiterpenoids or esters; there was a general decrease in the yield of all components compared to the essential oil and acetone extract.
Methods of Atomic Spectroscopy in Studying Properties and the Behavior of Nanoscale Magnetic Materials in Biological Systems
Authors: Kubrakova I. V. , Grebneva-Balyuk O. N. , Pryazhnikov D. V. , Kiseleva M. S. , Efanova O. O.
Published: April 2024

In this review, we provide an overview of methods for synthesizing magnetic nanoparticles (MNPs) with potential applications to biomedical research. We explore how the structure and properties of these particles are related to their diverse uses in medical diagnostics and bioanalysis. Special emphasis is placed on MNPs containing noble metals, which serve as biomarkers or active agents. Specifically, we focus on the application of direct and combined methods of atomic spectroscopy (ETAAS, AES/ICP–MS) to biomedical research. Experimental approaches to studying the behavior and transformations of MNPs in vitro and in vivo are considered. The importance of proper sample preparation in simulating the behavior of nanoparticles in biological media is highlighted. We also examine the significance of preparation techniques for the accurate determination of dissolved and nanosized forms in biological samples. Lastly, we assess the potential for the comprehensive studies of MNP behavior within complex biological systems, pointing toward future directions in this dynamic and promising field of research.
Complexation of Humic Acids with Trace Elements: Methods and Approaches
Authors: Volkov I. V. , Polyakov E. V.
Published: April 2024

The review analyzes research over the past 20−25 years in the field of physical chemistry of complexation of humic acids with cations, including radionuclides, in aqueous solutions. Problems have been identified in describing the reactivity of humate complexes with consideration for the objective complexity of the chemical nature of humic acids as one of the main classes of natural organic matter. The main methods of modeling complexation with humic acids, experimental methods for separating humate complexes and unbound cations (ultrafiltration, dialysis, etc.), and direct instrumental (electrochemical and spectroscopic) methods for detecting complexes were considered. Attention was also paid to the practical aspect of using humic acids for the treatment of natural water and wastewater to remove pollutants—heavy metals and radionuclides. Published data on the sorption capacity of humic acids of various origins in relation to heavy metal cations and quantitative data characterizing the stability of humate complexes were analyzed.
Magnetic Photocatalysts Based on Nanocrystalline Manganese-Doped Titanium Dioxide
Authors: Zheleznov V. V. , Tkachenko I. A. , Ziatdinov A. M. , Opra D. P. , Vasilyeva M. S. , Saritsky D. A. , Tarasov E. V. , Kuryavyi V. G.
Published: April 2024

Manganese-doped anatase with a nanosized morphology (as spherically shaped nanoparticles) has been synthesized under hydrothermal conditions. It has been shown that manganese is incorporated into the titanium dioxide structure to form substitutional solid solutions. At high dopant concentrations, part of the introduced manganese goes to the formation of α-MnO2. A significant increase in the optical activity in the visible range and a decrease in the bandgap width down to ~2.4 eV are observed for manganese-doped anatase because of the appearance of extrinsic (multivalent Mn ions) and intrinsic compensating (oxygen vacancies) defects. It has been found that manganese-doped samples are diluted magnetic semiconductors, and the magnetic characteristics increase with increasing manganese content. All manganese-containing samples demonstrate photocatalytic activity in the degradation reaction of indigo carmine when irradiated with visible light. The degree of dye degradation depends on the content of manganese in the samples and reaches 90%.
Oxidative Dehydrogenation of Ethane on Oxide-Supported Vanadium Phosphorus Oxide Catalysts
Authors: Malygin A. A. , Yaroslavtsev A. B. , Zhilyaeva N. A. , Elizarova V. I. , Mironova E. Yu. , Malkov A. A. , Bodalyov I. S.
Published: April 2024

Comparative results of studying the oxidative dehydrogenation of ethane (ODE) on catalytic vanadium-phosphorus oxide systems deposited by the molecular layering method on the surface of oxide supports (Al2O3, SiO2) have been presented. It has been found that the highest activity in ODE and selectivity for ethylene are exhibited by vanadium-phosphorus-containing catalysts. The influence of the acidity of catalytic systems on the activity and selectivity of the process has been revealed. The selectivity of the ODE process for ethylene reaches 90%. An increase in the oxygen concentration in the initial mixture from 3.5 to 20% leads mainly to a decrease in the selectivity of the ODE process with respect to the ethylene yield.
Photoinduced Dynamics of Spin Centers in Carbon-Modified Titanium Dioxide Nanotubes
Authors: Kytina E. V. , Savchuk T. P. , Gavrilin I. M. , Konstantinova E. A.
Published: April 2024

Arrays of titanium dioxide (TiO2) nanotubes with different chemical compositions have been synthesized; their structural properties have been studied, and the characteristics of spin centers (defects) have been determined. All samples have appeared to contain carbon. It has been established that the main type of spin centers in TiO2 nanotubes are dangling carbon bonds, and their concentration correlates with the carbon content in the obtained structures. Under illumination, a reversible increase in the concentration of defects occurs, which is caused by their photoinduced recharging in the process of impurity absorption. This process is accompanied by an increase in the concentration of photoexcited electrons in the conduction band. The originality and novelty of the work are determined by the development of a method for controlling the density of defects and, accordingly, the concentration of photoinduced electrons by thermal treatment of samples under various conditions. The results open up new possibilities for the development of photocatalysts based on titanium dioxide nanotubes with a controlled electron concentration in the conduction band that function in the visible range of the spectrum.
Chemical Deposition of CdxPb1 – xS/CdyS Thin-Film Composite Structures
Authors: Selyanina A. D. , Maskaeva L. N. , Voronin V. I. , Anokhina I. A. , Markov V. F.
Published: April 2024

Thin films of CdxPb1 – xS (0 ≤ x ≤ 0.094) substitutional solid solutions of cubic structure B1 (space group Fm) were prepared by chemical deposition and characterized by X-ray diffraction, scanning electron microscopy, EDX elemental analysis, and Raman spectroscopy. Once the cadmium sulfate concentration in the batch reached some critical value (0.1 mol/L), the films formed involved two autonomous phases: CdxPb1 – xS substitutional solid solutions and hexagonal cadmium sulfide CdyS of structure В4 (space group P63mc). The method and its parameters as proposed are efficient for manufacturing heterostructures in the CdS–PbS system in one-pot deposition.
Effect of Fluorine on Thermoluminescence in LiMgPO4
Authors: Kalinkin M. O. , Akulov D. A. , Gyrdasova O. I. , Abashev R. M. , Surdo A. I. , Medvedeva N. I. , Kellerman D. G.
Published: April 2024

Fluorine-doped lithium magnesium phosphate has been studied for the first time. It has been shown that fluorine significantly enhances the intensity of thermally stimulated luminescence. To find the preferred positions of fluorine and structural distortions caused by aliovalent substitution, ab initio calculations have been performed, which demonstrate that fluorine is not included into the (PO4)3– anion; rather, it promotes the formation of clusters simultaneously containing lithium and fluorine ions.
Phase Equilibria and Thermodynamic Properties of Phases in the H2O–Gd(NO3)3 System
Authors: Dzuban A. V. , Novikov A. A. , Nesterov A. V. , Qianchen Sh. , Kovalenko N. A. , Uspenskaya I. A.
Published: April 2024

Solid–liquid equilibria in the system H2O–Gd(NO3)3 were measured from –20 to 70°C using the isothermal saturation method. The Pitzer–Simonson–Clegg thermodynamic model was implemented to obtain the temperature dependence of Gd(NO3)3⋅6H2O solubility constant, to calculate salt solubility and to construct a phase diagram of the system from eutectic point to hydrate melting. Thermochemical properties of gadolinium nitrate aqueous solutions, such as dilution enthalpies and heat capacities, were assessed also. The model has shown to be reliable for phase equilibria calculation from –35 to 90°C and from 0 up to ~15 mol % of salt as well as the thermodynamic properties of Gd(NO3)3 aqueous solutions at room temperature and around it.
Thermodynamics of Cesium Molybdate-Based Single Crystals: Standard Enthalpy of Formation, Lattice Enthalpy, and Heat Capacity
Authors: Matskevich N. I. , Semerikova A. N. , Trifonov V. A. , Samoshkin D. A. , Chernov A. A. , Stankus S. V. , Luk’yanova S. A. , Shlegel’ V. N. , Zaitsev V. P. , Kuznetsov V. A.
Published: April 2024

Cs2MoO4 and Li1.9Cs0.1MoO4 crystals were grown from melt by the low-thermal-gradient Czochralski technique. The standard formation enthalpy of cesium molybdate Cs2MoO4 was measured by solution calorimetry. The heat capacity of Li1.9Cs0.1MoO4 was measured by differential scanning calorimetry (DSC) in the temperature range 320–710 K. The lattice enthalpy of Cs2MoO4 was calculated using the Born-Haber cycle. Cesium molybdate was shown to be thermodynamically stable to decomposition into constituent simple oxides (Cs2O and MoO3), which made it promising for application. Li1.9Cs0.1MoO4 experienced no phase transitions in the temperature range 320–710 K.
CVD Synthesis of Graphitic Carbon Nitride Films from Melamine
Authors: Ermakova E. N. , Maksimovskii E. A. , Yushina I. V. , Kosinova M. L.
Published: April 2024

A CVD technique has been developed for the deposition of homogeneous graphitic carbon nitride films on silicon and quartz glass substrates using melamine as a precursor. Layer-by-layer deposition at low precursor loadings makes it possible to deposit a film up to 1.4 µm thick; however, it is possible to achieve large thicknesses by multiple repetition of the experimental cycle. The effect of synthesis parameters on the surface morphology of deposited layers has been studied by scanning electron microscopy. The chemical composition and structure of graphitic carbon nitride films are confirmed by a set of spectroscopic methods and X-ray diffraction. The optical properties have been studied using diffuse reflectance spectroscopy. Scanning electron microscopy and X-ray diffraction analysis have shown that films deposited at temperatures of 550–650°C have a layered microcrystalline structure. The bandgap of the obtained samples was 2.76–2.93 eV.
Interaction of the Bipyridyl Gold(III) Complex with Anions of Thiol-Containing Acids in Aqueous Solution
Authors: Mironov I. V. , Kharlamova V. Yu. , Hu J.
Published: April 2024

The equilibria of stepwise substitution Au(bipy)+ OH– = Au(bipy)ClOH+ + Cl– and Au(bipy)+ 2OH– = Au(bipy)+ 2Cl– in aqueous solution at T = 25°C and I = 0.2 M (NaCl), log β1 = 9.22, log β2 = 16.61 have been studied. For bipyridyl complexes Au(bipy)(X = Cl, OH) at pH 2.0 and 7.4, redox interactions with anions of thiol-containing acids (glutathione, cysteine, thiomalate) have been studied. In all cases, at the initial stage, a rapid reduction of gold(III) to gold(I) was observed with the simultaneous release of bipyridyl. A detailed analysis of UV spectra showed that the main products of gold(III) reduction are highly stable gold(I) thiolate complexes. The presence of further slower steps depends on the initial ratio of thiol to gold.