bluuebunny/crossref_metadata_2025 huggingface dataset:
Competition, Credit Risk and Banks’ Franchise Value: Evidence from Kuwait and COVID-19 Policy Insights
Authors: Aldousari Abdullah N. , Mohammed Ahmed
Published: September 2024

Purpose: This paper investigates the franchise-value paradigm theory proposed by Keeley (1990) in relation to the competition-credit risk nexus in Kuwait’s banking sector before and during the COVID-19 pandemic. The study explores the theories of fragility hypothesis, stability, and the non-linear argument, which are subjects of controversy to assess the competitive behavior regarding credit risk. Study design/methodology/approach: Panel data techniques were utilized (OLS, Random and Fixed effects). We divided the sample into two periods: 2010-2019 and 2020-2021 to capture the impact of the external shock. Sample and data: The sample includes five commercial banks operating in Kuwait, with data sourced from annual reports spanning 2010 to 2021. Results: The findings support the “neutral view”, indicating that intensified competition among banks erodes banks’ franchise value and induces credit risk, as posited by the “fragility hypothesis”. Furthermore, higher concentration increases credit risk and insolvency, aligning with the too-big-to-fail and competition-stability notions (Boyd & De Nicolo, 2005; Mishkin, 2006). Notably, during the COVID-19 period, banks’ capital buffers succeeded in absorbing credit risk, nonetheless failed to diversify away from interest-income activities. Originality/value: The study contributes by examining competitive behavior and pricing strategies above marginal costs. It also explores the impact by considering a combination of bank-control variables such as banks’ capital, size, profitability, solvency, and diversification, in relation to competition dynamics and the presence of COVID-19. Research limitations/implications: These findings offer perceptions for policymakers towards dealing with the competition-stability nexus and provide a policy implication on how regulators ought to behave during financial turmoil.
Inorganic Nanoparticle Functionalization Strategies in Immunotherapeutic Applications
Authors: Mao Wei , Yoo Hyuk Sang
Published: September 2024

Nanotechnology has been increasingly utilized in anticancer treatment owing to its ability of engineering functional nanocarriers that enhance therapeutic effectiveness while minimizing adverse effects. Inorganic nanoparticles (INPs) are prevalent nanocarriers to be customized for a wide range of anticancer applications, including theranostics, imaging, targeted drug delivery, and therapeutics, because they are advantageous for their superior biocompatibility, unique optical properties, and capacity of being modified via versatile surface functionalization strategies. In the past decades, the high adaptation of INPs in this emerging immunotherapeutic field makes them good carrier options for tumor immunotherapy and combination immunotherapy. Tumor immunotherapy requires targeted delivery of immunomodulating therapeutics to tumor locations or immunological organs to provoke immune cells and induce tumor-specific immune response while regulating immune homeostasis, particularly switching the tumor immunosuppressive microenvironment. This review explores various INP designs and formulations, and their employment in tumor immunotherapy and combination immunotherapy. We also introduce detailed demonstrations of utilizing surface engineering tactics to create multifunctional INPs. The generated INPs demonstrate the abilities of stimulating and enhancing the immune response, specific targeting, and regulating cancer cells, immune cells, and their resident microenvironment, sometimes along with imaging and tracking capabilities, implying their potential in multitasking immunotherapy. Furthermore, we discuss the promises of INP-based combination immunotherapy in tumor treatments.
Emergy Evaluation of Ecological Engineering for Riparian Restoration in the Upper Reaches of the Yangtze River, China
Authors: Tang Ting , Luo Jiaqi , Yuan Jia
Published: September 2024

Complex hydrological regimes and rugged topography in mountainous cities have increasingly compromised urban riparian zones, presenting marked restoration challenges. This study conducted restoration trials along the Jiulongtan riparian zone, located in the upper reaches of the Yangtze River (URYR), China. It featured 2 major ecological engineering interventions: (a) establishing semi-natural meadows and applying braided branched meshes to the riparian slope revetment and (b) constructing littoral woods and managing microtopography and sediment in the floodplain area. Furthermore, emergy evaluation was utilized to gauge the effectiveness of these restoration strategies and to assess the sustainability of the reconstructed riparian ecosystems. The following results were obtained: (a) Both the restored slope revetment (RSR) and restored floodplain (RF) ecosystems achieved a state of performance equilibrium after their implementation, with the former benefiting from renewable energy investments and the latter effectively utilizing local resources; (b) service yield outcomes highlighted significant enhancements in species diversity within the reconstructed ecosystems; plant diversity emerged as the primary contributor to total service yield, recording 3.71 × 10
18
sej/a for the RSR and 5.50 × 10
18
sej/a for the RF; (c) the emergy sustainability index values of 1.98 for the RSR and 5.16 for the RF suggest robust sustainability potential, particularly for the RF, even amid intense environmental stresses. These results affirm the success of the innovative restoration strategies employed for riparian reconstruction in the URYR’s mountainous urban settings, offering valuable insights and reference for future restorative decisions in response to complex hydrological regimes and topography of urban riparian zones, both within the URYR and elsewhere.
Statistical Analysis and Critical Aspects of Surface Measurement using Mechanical Pin-Wheel Machines
Authors: Mascolo R. , Calvanese G. , Giorleo L. , Scaglia E.
Published: September 2024

The publication of the “Measuring Instruments Directive - MID” (European Directive 2014/32/UE) has determined the inclusion of area measuring machines in the category of legal metrology devices. Leather must follow similar rules for other goods traded by means of a measurement. Finished leathers are usually sold by area and the measurement for verification purposes in commercial trades is regulated by the International Contract No 7 (1998) between the ICT and the ICHSLTA. This contract provides specific indications on commercial issues and defines rules for area checking in case of legal disputes. In general, the contract allows the use of any agreed machine between seller and buyer (mechanical or optoelectronic),  but in the event of a dispute it refers exclusively to pin-wheel  machines according to ISO 11646 standard. This requirement has  been defined without the provision of any technical support and does not consider the deviations of the results using other devices. Furthermore, ICT and ICHSLTA agreed that official controls shall  be carried out only in specific Measurement Institutes, among which  only 5 around the world have a working instrument, and only one  has accredited the test according to ISO/IEC 17025. In this study, 13 small batches of different leather articles were used  in an interlaboratory trial that involved 8 participants, including  4 European ICT/ICHSLTA official Measurement Institutes. By  means of a statistical analysis of the results, the scope of this study  is the identification of critical aspects related to the use of pinwheel machines with particular reference to leather (dimension,  deformability, etc) and device characteristics.
Transformation of the land road system of the Karelian Isthmus and the Neva lands in the 17th century
Authors:   Peter  the  Great  St.  Petersburg  Polytechnic University, Vostrov Alexey  V.
Published: September 2024

The article examines the transformation of the system of land roads of the Neva lands and the Karelian Isthmus during the 17th century: from the events of the Time of Troubles of Russia to the Northern War of 1700–1721. Based on the descriptions of the Vodskaya Pyatina road network of the beginning of the 16th century, as well as its subsequent development, roads on the Novgorod side of the Russian-Swedish border are presented. Based on the report of 1556, the Swedish roads of the Finnish lands and on the Karelian Isthmus are described. Based on Swedish maps of the middle of the 17th – early 18th century, as well as on the memories of foreign travelers, the changes that occurred with the land communications indicated in the names of lands after the Stolbovsky Peace Treaty of 1617 are analyzed, the main factors that influenced their development are highlighted.
Letters of Lubeck Magistrate to Revel concerning the trade of Revalfahrer of the last quarter of the 15th century (from the Tallinn City Archive)
Authors:   Yaroslav-the-Wise Novgorod State University, Ushakov Artem V.
Published: September 2024

The article presents the results of a search in the Tallinn City Archive (Tallinna Linnaarhiiv), made with the materials of the collection of letters from the Lubeck City Council to the magistrate of Reval concerning the RevalfahrerCorporation. The search revealed five documents dating back to the last quarter of the 15th century. They present the specifics of the interaction of the Revel guests with the Lubeck City Council, the mechanism for hiring soldiers on merchant ships and the specifics of paying them salaries, as well as the specifics of chartering merchant ships. Much attention in this article is paid to the common traditions in the trade of the Nowgorodfahrer and the Revalfahrer of Lubeck. The appendix to the article contains the full texts of the Hanseatic sources, annotated in Russian and the necessary comments.
Round table of young scientists “Dialogue between East and West in the Middle Ages: politics, economics, culture”
Authors:   Institute of History and Politics, Moscow Pedagogical State University, Sazonov Danila V. ,   Institute for Scientific Information on Social Sciences, Russian Academy of Sciences, Savchenko Alexey F. ,   Institute for Scientific Information on Social Sciences, Russian Academy of Sciences
Published: September 2024

The review presents the topics of the reports delivered on November 3, 2023 at the round table of young scientists “Dialogue of East and West in the Middle Ages: Politics, Economy, Culture”at the Moscow Pedagogical State University.
VARIABILITY OF WORLDVIEW EXPERIENCE:BRICOLAGE VS “BLUE PILL”
Authors:   South Ural State Humanitarian and Pedagogical University, Borisov S. V.
Published: September 2024

Worldview experience is structured as bricolage. Bricolage is deeply rooted in culture and is the essence of any cognitive process. It does not matter what cognitive models are used. Bricolage has always been and will always be the default epistemology. That is, piecing together what is discovered by chance has always been the primary way of acquiring knowledge. Intersubjectivity triggers a process from facts to data, and then from data to truth, with the term “truth” in this socio-cultural context generally being substituted for the terms “belief system” or “metanarrative”. Therefore, an individual belief system will only focus on facts and data that reinforce and support it. However, any individual “truth” will be subject to constant revision because it is in close contact with reality, which in fact is usually not, what it appears to be. Thus, a new bricolage is formed, a new worldview is acquired. While formalized ways (styles) of thinking tend to contain, bricolage embraces the external and the accidental and ensures development.
REPRESENTATIONS OF EVERYDAY LIFE AND IMAGES OF THE TECHNOLOGICAL FUTURE: FOLLOWING COMMENTS ON SOCIAL MEDIA
Authors:   National Research Tomsk Polytechnic University, Shavlokhova A. A. , Bragin A. D. ,   National Research Tomsk Polytechnic University
Published: September 2024

Technological innovations and achievements of our country have a different impact on the mass “consumer” of information, who tends to express their point of view precisely in “digits”. Technological progress determines the discourse of tomorrow, but at the same time, the picture remains unclear regarding the image of the future, which is represented in the contexts of the present and in everyday life. In order to conduct a comprehensive analysis of the representations of everyday life in social media (VK), which form the process of planning the future based on disciplinary and symbolic spaces (in relation to the “technological well-being of Russia”), the authors developed a three-stage complex method (collection, structuring and analysis of social network comments) in relation to the fundamental part of the study (theoretical basis). The article concludes that despite the complexity of analyzing digital comments, it is possible to identify those trigger points that can provoke negative connotations among users regarding specific technological achievements. It is concluded that propositional attitudes based on opinions and statements in the form of comments on a social network represent a representation of everyday life, which forms value-semantic attitudes regarding images of the future (including the “technological well-being of Russia”).
Design Of A Centralised Anaerobic Digestion Plant In Ireland.
Authors:   ,   Cork Institute of Technology, O'Meara Diarmuid
Published: September 2024

"Climate change is brought about by greenhouse gases emitted to the earth’s atmosphere by fossil fuels. Renewable energy sources are seen as an alternative to fossil fuels. Examples of renewable energy sources are biofuels which are a method of reducing the emission of greenhouse gases. One form of biofuels is biogas that is produced during the anaerobic digestion process. In this thesis pig slurry is used to produce biogas. In this project, the optimum design process for a centralised anaerobic digestion plant was established in the literature review, The optimum process for anaerobic digestion plant design in Ireland was investigated. The proposed feedstock for the centralised anaerobic digestion plant was pig slurry. As part of this work a Microsoft Excel spreadsheet was developed to determine the size of digester tanks depending on farm sizes. A technical, environmental and financial analysis was conducted on various size anaerobic digestion plants. These analyses provided the number of houses a pig farm could provide with heat and power and the amount of vehicles each pig farm could generate methane gas for. A mechanical and process design was carried out on an anaerobic digestion plant for pig farmers. Elements of the anaerobic plant were designed such as the roof system, heating system, agitators, pumps and pipes. A process design incorporating control valves to monitor the temperature of the pig slurry entering the digester was also conducted. Laboratory work was undertaken to confirm that the theoretical values for pig slurry used in the technical analysis in chapter three were correct. The methane gas generated from five samples of pig slurry was recorded. A structural design was also developed for design of the reinforced concrete digester tanks to the Eurocode. A Microsoft Excel spreadsheet determined the wall thickness and steel required are suitable to ensure crack widths are limited in the digester tank. The digester tanks were also sized with a reinforced concrete heel to prevent flotation in case of a high water table."
Development Of A Low Cost Instrument For Tidal Flow Measurement
Authors:   ,   Cork Institute of Technology, Daly Thomas
Published: September 2024

"This project examines current technology for the production of energy from wave and tidal sources and the pros and cons of the different types of technology available. It also looks at the possibility of producing energy from tidal streams on a micro scale for local use. It identifies some of the barriers to this and attempts to solve one of those barriers by developing a low cost instrument which would be capable of assisting in the surveying of possible sites for micro tidal energy production in a cost effective way. As part of this process an off the shelf marine grade instrument is identified which if adapted and deployed correctly could carry out the required function. A deployment device was designed with the use of computational fluid dynamics that was capable of housing the instrument and its ancillary electronics while at the same time not interfering excessively with the flows that are to be measured. A design was eventually arrived at which produced an error of less than 3% while still giving a resolution of 0.05m/s. The CFD model which was developed was then verified with the use of a wind tunnel. Systems for the mooring of the device and for adjusting the buoyancy of the device, so that flow measurement could be taken at pre-determined depths are also proposed. A system of powering the device for use over prolonged periods is also proposed."
Creep Behaviour Of Hand Laminated Glass Reinforced Polymer Composites.
Authors:   ,   Cork Institute of Technology, Quinn Brian
Published: September 2024

"The creep behaviour of hand laminated, glass fiber reinforced polyester composites were studied at coupon level, due to the use of similar materials in long term load bearing civil and structural engineering applications. Creep predictions were made by fitting the parameters of several viscoelastic models to experimental creep data as well as two accelerated test methods, time temperature superposition (TTS) and frequency time transformations (FTT). TTS experiments were carried out in a dynamic mechanical analyzer (DMA) in three point bending mode for three types of material systems. Creep compliance master curves representing the linear viscoelastic creep response at reference temperatures of 35‘^C, 45”C and 55°C were generated by using a manual curve shifting procedure, while the validity of TTS was explored by assessment of the temperature dependence of the curve shifting. The FTT method of synthesizing the linear viscoelastic creep response was used by initially carrying out a series of oscillatory measurements in three point bending mode in the DMA. The dynamic stiffness as a function of frequency was transformed into time domain creep compliance by means of an inverse fast Fourier transform and numerical integration routine implemented in National Instruments’ LabView 8.2. The technique was also initially tested by synthesizing a number of known exact functions in order to give confidence in the results. The synthesized functions were generated for periods of two and four hours and compared to actual time domain creep tests carried out over a two hour period. The results show good potential for using FTT as a creep characterization technique, provided that the frequency dependent properties can be successfully extrapolated to the low frequencies required for synthesis. Procedures for theoretically estimating the static and transient response of a polymer composite structure in flexure were also explored through a combination of theoretical and finite element approaches. The results showed excellent correlation between theoretical and finite element models for static analysis while transient finite element analysis suggests that increased temperature can dramatically increase the creep rate of a polymer composite structure in flexure."
Rubble-mound Structure Design In The Coastal Environment
Authors:   ,   Cork Institute of Technology, Murphy Jack
Published: September 2024

"The main aims of this thesis were to investigate the main aspects of the design and implementation of rubble-mound structures as a form of shoreline stabilisation and coastal defence. An emphasis has been placed on the Irish context of how these structures have been implemented in the past. The intention was that this work would improve the understanding of the use of these structures for future projects both in Ireland and internationally. This work required a literature review which investigated the general aspects of rubble-mound structures, the coastal environment, and the theory of designing the structures’ layout, cross-section and impact upon the local shoreline as well as the subsequent environmental, economic and social impacts such a project might have. Furthermore detailed case studies have been undertaken on beaches in Ireland where rubble-mound beach stabilisation structures have been proposed or implemented. A computer programme has been developed capable of designing the structural layout and cross section for two forms of rubble-mound shoreline stabilisation structures, namely offshore breakwaters and groynes. The Rubble-mound Structure Analysis and Design System is also capable of predicting the shoreline response and the carbon footprint and cost of both structural systems. This system is based on the information presented in the literature review. RSADS has facilitated a detailed study into the sizing of Rubble-mound structure armour units which are the primary structural element of this form of coastal defence. This work has culminated in a detailed study of Youghal Beach in County Cork. This study has involved a beach level survey, and a detailed review of the coastal processes and existing coastal structures. Coastal structures which have been proposed for Youghal by Malachy Walsh & Partners have also been reviewed. Finally RSADS has been implemented to carry out a full design for the shoreline at Youghal resulting in a final proposal of a rock armoured rubble-mound groyne field. Finally the conclusions on the work carried out, future work and the topic in general are presented in the final chapter of this thesis."
Semi-rigid Steelwork Connections
Authors:   ,   Cork Institute of Technology, Murphy Conor
Published: September 2024

This thesis sets out to assess the stiffness of typical fin plate steelwork connections. The classification of joints as pinned, semi-rigid or fixed is described and the different models of moment-rotation relationship are explained. Eurocode treatment of steelwork connections is assessed with particular emphasis on joint stiffness. Procedures for the design of fin plate connections are set out and an example presented and a spreadsheet developed. Tests on a number of fin plate connections were carried out in the Heavy Structures Laboratory, to determine the moment rotation characteristics. The finite element software LUSAS was used to analyse the fin plate connections and the results are compared with the results from the Laboratory tests. It is concluded that fin plate connections should be considered to be effectively pinned.
A Qos Aware Framework For Wireless Sensor Networks In Industrial Environments
Authors:   ,   Cork Institute of Technology, Villaverde Berta
Published: September 2024

"Wireless Sensor Networks (WSNs) are a key enabling technology for industrial monitoring applications where the use of wireless infrastructure allows high adaptivity and low cost in terms of installation and retrofitting. Although WSNs present several advantages over traditional wired monitoring systems, there is significant concern as to the reliability of wireless communications due to the unpredictability of the wireless channel, which is inhibiting the widespread adoption of the technology. Furthermore, due to the diverse range of monitoring applications that are found in industrial environments and their differing requirements, there is a need for quality of service (QoS) provisioning so that the technology can be successfully adopted. However, achieving QoS provision in W'SNs is not a straightforward task due to the strict energy and memory limitations within sensor nodes as well as the bandwidth restrictions imposed by the technology. Fundamental QoS characteristics for industrial monitoring applications are bandwidth availability for bursty, event-based or data logging traffic, reliability, soft-delay bounds, data-relevance differentiation and network lifetime. This thesis presents an algorithmic based QoS Framework for WSNs targeting monitoring applications in industrial environments. The proposed framework is composed of a suite of schemes located at the networking and MAC layers that work in conjunction with the lower layers, as defined by the IEEE 802.15.4 standard, to satisfy the QoS requirements of industrial monitoring applications while taking into consideration the limitations imposed by the resource constraints of the sensor nodes. The performance of the proposed QoS framework is gauged against existing Standards and networking protocols for WSNs in industrial environments using a realistic computer simulation environment. The evaluation results highlight the limitations of existing approaches in fulfilling industrial monitoring application QoS requirements across a range of simulation environments and settings. In contrast, the proposed QoS Aware Framework, which simultaneously considers sensor nodes limitations and application QoS requirements, has been shown to satisfy application needs with low memory and computational overhead. For instance, the proposed lnRout route selection algorithm achieves gains from 4% to 60% in the number of successfully delivered packets and the proposed D-SeDGAM algorithm for bandwidth allocation achieves gains of 100% to 145% in terms of the number of packets delivered on time at the sink."
The Structural Performance Of Timber Connections
Authors:   ,   Cork Institute of Technology, Coleman Daniel
Published: September 2024

"This thesis sets out to assess the behaviour of mechanically fastened timber-to-timber connections. The design aspects of timber connections are described in detail, with particular emphasis on nailed connections. The effects of inherent variations in timber properties on joint behaviour are also described. The two types of connections considered were: ■ Corbel (cantilever); ■ Splice. For each connection type, different nail configurations, nail diameters and shaft lengths were used. Testing undertaken was conducted to investigate the influence of a number of nail configurations on a connection’s initial stiffness. The test results, presented using moment- rotation curves are also used to validate the finite element model generated. The tests show the effect that different nail configurations have on the initial stiffness of the joint. Eurocode 5 design calculations have been explained and an Excel spreadsheet developed to determine the elastic moment capacity of the connection considered. The force distribution of the nail groups was determined on the basis of an elastic analysis. The moment capacity of a specified connection can be determined as a result. Using this approach, the elastic moment capacity for each of the connection types considered was determined. A comparison between experimental test and Eurocode results is also presented. LUSAS VI 4.7 software package was used to model the corbel-type connection. Preliminary modelling of a nail-to-timber and timber-to-timber interaction was carried out, considering the use of the slideline function and joint elements. The ability of the model to simulate the actual behaviour was investigated by comparing the models with experimental results."
APPLYING INTELLIGENT REFLECTIVE SURFACES TO IMPROVE SNR IN LOW-EARTH ORBIT SATELLITE COMMUNICATION SYSTEMS
Authors: Яхья Х.М. , Климов Д.А.
Published: September 2024

Рассматривается влияние интеллектуальных отражающих поверхностей на уменьшение затухания сигнала на нисходящей линии связи спутника, расположенного на низкой околоземной орбите. Анализируется влияние количества элементов отражающей поверхности и местоположения пользователя на качество сигнала и максимальную пропускную способность канала связи.

The effect of intelligent reflective surfaces on reducing signal attenuation on the downlink of a satellite located in low Earth orbit is considered. The influence of the number of elements of the reflective surface and the user’s location on the quality of the signal and the maximum throughput of the communication channel is analyzed.
Extraction of Ether-Ethonol Mixture fromPowders by the Example of GunpowderBrand «Sunar 308WIN» UsingSupercritical CО
Authors: Билалов Т.Р. , Гумеров Ф.М. , Гатина Р.Ф.
Published: September 2024

С использованием сверхкритической флюидной экстракционной установки циркуляционного типа марки R-401 фирмы «Reaction Engineering, Ink.» (ЮжнаяКорея) при температуре 323 К в интервале давлений 10,0-35,0 МПа определенарастворимость дифениламина в сверхкритическом диоксиде углерода (СК-СО).Экспериментальные данные приведены с применением уравнения Пенга -Робинсона. Представлены результаты СК-С0-экстракционного извлечения спирто-эфирной смеси из образцов охотничьего пороха марки «Сунар 308WIN», определены параметры процесса, отвечающие максимальному сохранению дифениламина в порохе, показана его эффективность.

The results of experimental studies of solubility of diphenylamine in supercriticalcarbon dioxide (SC-CО) are presented. Research was carried out at temperature323.15 К in the pressure range from 10 to 35 MPa on the experimental plant implementinga dynamic research method, produced by «Reaction Engineering, Ink.» (South Korea).Experimental solubility data are described using the Peng - Robinson equation ofstate. The results of SC-CО-extraction process of ether-ethanol mixture from thesamples of «Sunar 308WIN» brand gunpowder are presented, and process parameterscorresponding to the maximum preservation of diphenylamine in the powder aredefined, the efficiency of this process is shown.
Release Kinetics of the Nitroxyl Radicaltempone from D,L-Polylactide Foamed in the Environment of Supercritical Carbon Dioxide
Authors: Иванова Т.А. , Чумакова Н.А. , Голубева Е.Н. , Лунин В.В.
Published: September 2024

Впервые метод электронного парамагнитного резонанса (ЭПР) использован для количественного описания процесса высвобождения парамагнитного биологически активного вещества из полимерного биодеградируемого матрикса. В качестве парамагнитного соединения выбран стандартный спиновый зонд TEMPONE, в качестве полимера - D,L-полилактид, вспененный в среде сверхкритического диоксида углерода (СК-CO). Показано, что высвобождение TEMPONE из пористого D,L-полилактида в фосфатный буфер с pH 7,4 происходит постепенно, без периодов выброса и стагнации, что свидетельствует о принципиальной возможности применения используемой технологии импрегнации и вспенивания полимера для создания материалов медицинского назначения.

For the first time, the EPR-method was used to quantitatively describe the process of releasing a paramagnetic biologically active substance from a polymer biodegradable matrix. A standard TEMPONE spin probe was chosen as the paramagnetic compound, and D, L-polylactide foamed in supercritical carbon dioxide was used as the polymer. It is shown that the release of TEMPONE from porous D, L-polylactide into phosphate buffer with pH 7,4 occurs gradually, without periods of burst and stagnation, which indicates that it is possible in principle to use the used technology of impregnation and foaming of the polymer to create materials for medicalpurposes.
Impregnation of Polymer Materials in Supercritical Media
Authors: Залепугин Д.Ю. , Тилькунова Н.А. , Чернышова И.В.
Published: September 2024

В обзорной статье рассматриваются достижения за последние годы в области импрегнации полимеров в сверхкритических средах. В частности, описаны новые подходы к проведению процесса импрегнации полимеров, показана возможность использования для этих целей новых суб- и сверхкритических сред. Приведены конкретные примеры и условия проведения данных процессов, а также обсуждаются новые области применения метода.

The review summarizes the achievements in the field of polymer impregnation during latest years. In particular, new methods of impregnation process and application of some new fluids are demonstrated. Concrete examples and conditions of impregnation processes and new areas of method applications are discussed.
Biocatalytic Transesterification of Oleic Acid Triglyceride in Supercritical Carbon Dioxide
Authors: Лакина Н.В. , Сульман Э.М. , Долуда В.Ю. , Матвеева В.Г.
Published: September 2024

Показана перспективность использования катализаторов на основе иммобилизованной липазы в реакции переэтерификации триглицерида олеиновой кислоты (ТГОК) метанолом в среде сверхкритического диоксида углерода. При оптимальной температуре 40 °С, давлении СО 15,0 МПа и мольном соотношении ТГОК: метанол = 1:3 выход метилового эфира олеиновой кислоты существенно выше по сравнению с получаемым в среде метанола при атмосферном давлении.

The prospects of using catalysts based on immobilized lipase in the transesterification of oleic acid triglyceride (THC) with methanol in supercritical carbon dioxide was shown. At an optimum temperature of 40 °C; a C0 pressure of 15.0 MPa and a THC: methanol = = 1:3 molar ratio the yield of oleic acid methyl ester is significantly higher than that obtained in methanol at atmospheric pressure.
Peculiarities of Polylactide Methacrylation in the Supercritical Carbon Dioxide Medium
Authors: Копылов А.С. , Каплин В.С. , Глаголев Н.Н. , Соловьева А.Б.
Published: September 2024

В среде сверхкритического диоксида углерода с использованием реакции уретанообразования осуществлена модификация полилактида с получением его метакрилатных производных. Фотополимеризацией модифицированных полилактидов получены материалы с пространственносшитой структурой, пригодные для формирования имплантатов в регенеративной медицине и тканевой инженерии.

Polylactide was modified in the medium of supercritical carbon dioxide via the reaction of urethane formation to obtain methacrylate derivatives. Photopolymerization of modified polylactides leads to the formation of spatially cross-linked materials that can be used for the production of implants in the regenerative medicine and tissue engineering.
Phase Diagram of the Supercritical Carbon Dioxide - Ethylcarbitol System
Authors: Билалов Т.Р. , Завьялова Н.Б. , Гумеров Ф.М.
Published: September 2024

Исследована фазовая диаграмма системы «сверхкритический диоксид углерода (СК-С0) - этилкарбигол (моноэтиловый эфир диэтиленгликоля)» на изотермах 308, 318 и 323 K, дополняющая имеющиеся литературные данные, и проведено их описание с использованием уравнения состояния Пенга-Робинсона и закона смешивания Мухопадхьяи и Рао. Предложен диапазон термодинамических параметров, позволяющих эффективно удалять этилкарбигол из полимеров при их пластификации и сохранять при этом растворимые в СК-С0 компоненты готового продукта.

The phase diagram of the system «CO - diethylene glycol monoethyl ether (ethylcar-bitol)» was studied on isotherms 308, 318 and 323 K. The available literature data are supplemented by the results of this study. The obtained data are described using the Peng-Robinson equation of state and the Mukhopadhyaya and Rao mixing law. A range of thermodynamic parameters is proposed to effectively remove ethylcarbitol from polymers during their plasticization and to preserve the components of the finished product soluble in supercritical CO.
IMPREGNATION OF POLYMETHYLMETHACRYLATE WITH CARBAMAZEPINE IN SUPERCRITICAL CARBON DIOXIDE MEDIUM
Authors: Опарин Р.Д. , Белов К.В. , Ходов И.А. , Дышин А.А. , Киселев М.Г.
Published: September 2024

Проведена импрегнация двух образцов полиметилметакрилата (ПММА) карба-мазепином (КБЗ) в среде сверхкритического CO (СК-С0) при температурах 75 и 105 °С и постоянной плотности CO, равной 1,3 ее критического значения. Предварительно для определения кинетических параметров сорбции CO полимерной матрицей использовали ЯМР-спектроскопию высокого давления. Методом спектроскопии комбинационного рассеяния установлено, что оба образца полиметилметакрилата содержат карбамазепин, концентрация которого в полимере в ~2,7 раза выше в случае импрегнации при 105 °С по сравнению с 75 °С. Кроме этого показано, что в процессе импрегнации КБЗ не кристаллизуется в полимерной матрице, а образует раствор в ПММА, что, в свою очередь, хорошо согласуется с результатами рентгенофазового анализа. При этом установлено различие конформаций молекул КБЗ в полимерной матрице, импрегнированной при двух различных температурах.

In this work we performed an impregnation of polymethylmethacrylate with carbamazepine in SC-CO medium. Impregnation was carried out at two temperatures of 75 °C and 105 °C and SC-CO density equal 1.3 of its critical value. In the first stage, in order to define the kinetic parameters of CO sorption by polymer matrix, we applied high pressure NMR spectroscopy. Two impregnated polymethylmethacrylate samples were obtained upon impregnation process and further they were analyzed by Raman spectroscopy and powder X-Ray diffraction. Basing on the results of Raman spectroscopy we found that both impregnated samples contain carbamazepine, at that its concentration in polymethylmethacrylate impregnated at 105 °C is in ~2.7 times higher than in polymethylmethacrylate processed at 75 °C. It was also discovered that carbamazepine does not crystallize in the confinement of polymer matrix. Its solution in polymethylmethacrylate is formed instead. Moreover, processing temperature also affects on conformational state of carbamazepine molecules entrapped into polymer matrix.
Laser-Induced Supercritical Water
Authors: Жигарьков В.С. , Юсупов В.И.
Published: September 2024

Продемонстрирована возможность получения сверхкритической воды при поглощении лазерного импульса длительностью 8 нс пленкой золота толщиной 50 нм, находящейся в контакте с водой. Для оценки возникающего вблизи пленки скачка давления использовали измерение акустического давления в дальней зоне с помощью гидрофона на основе кристалла ниобата лития. Оценку скачка температуры проводили по реперной точке - температуре плавления золота. Показано, что при энергии лазерных импульсов 65 мкДж тонкий слой воды, контактирующий с металлической пленкой, находится в сверхкритическом состоянии в течение ~ 4,5 нс.

The work uses the possibility of formation supercritical water (SCW) upon absorption of a laser pulse with a duration of 8 ns by a 50 nm thick gold film, which is in contact with water. To estimate the growth of the pressure jump film, we used an approach based on measuring the acoustic pressure in the far field using a hydrophone based on a lithium niobate crystal. The temperature jump was estimated using a reference point - the melting point of gold. It is shown that at a laser pulse energy of 65 mJ, a thin layer of water in contact with a metal film is in a supercritical state for ~ 4.5 ns.
Diagnostics of the Critical State of Carbon Dioxide
Authors: Чайкина Ю.А. , Уманский С.Я.
Published: September 2024

Впервые, по данным эксперимента по малоугловому рассеянию света средой С0восстановлена зависимость дисперсии плотности и длины корреляций критических флуктуаций плотности от температуры Т. Установлено, что при критической плотности по мере приближения к критической температуре в интервале 10T < \\T- T\\ < 10 T, где T - критическая температура, длина корреляций флуктуаций плотности падает на 20 %. Дисперсия плотности не демонстрирует степенной расходимости: оставаясь практически постоянной внутри областей T > T и T < T, при переходе через критическую точку дисперсия плотности претерпевает скачок на 25 % величины, который может быть связан с особенностями постановки эксперимента.

For the first time, the temperature dependence of the density variance and the correlation length of critical density fluctuations is determined from the experimental data on small-angle light scattering by critical CO. It is found that at critical density of CO in the temperature range 10 T < \\T - T\\ < 10 T (where T is the critical temperature) the correlation length of density fluctuations decreases by 20 % as the critical point is approached. The value of density variance shows no power-law-type divergence: it remains practically constant in the temperature ranges T > T and T < T, but undergoes a 25 % stepwise change when passing through the critical point, likely due to the peculiarities of the experiment setting up.
Conformational Analysis of Mefenamic Acid in SC-CO-DMSO 2D NOESY Method
Authors: Белов К.В. , Батиста де Карвальо Л.Л.Е. , Дышин А.А. , Киселёв М.Г. , Соборнова В.В. , Ходов И.А.
Published: September 2024

С помощью метода 2D NOESY определена пространственная структура молекулы мефенамовой кислоты в растворе CK-CO с добавлением ДМСО (25 % и 10 %). Полученные в работе данные будут использоваться для расчета оптимальных параметров состояния процессов микронизации методом GAS.

The spatial structure of mefenamic acid molecule was investigated by the 2D NOESY in SC-CO with DMSO (25 % and 10 %). The results will be used to determine the optimal parameters of state for the micronization processing by GAS technique.
Micronization of Adi pic Acid via Supercritical Antisolvent Precipitation
Authors: Зуев Я.И. , Воробей А.М. , Гавриков А.В. , Паренаго О.О.
Published: September 2024

Исследовано влияние растворителя и концентрации микронизуемого вещества в растворе на размер и морфологию частиц адипиновой кислоты, осаждаемой методом сверхкритического антисольвентного осаждения (SAS). Увеличение концентрации адипиновой кислоты (АК) приводит к уменьшению размера ее частиц, а также к сужению распределения частиц по размерам. В зависимости от используемого растворителя и концентрации АК в растворе методом SAS возможно получение частиц различной морфологии размером от десятков до сотен микрон.

The effect of the solvent and the concentration of the micronized substance in the solution on the size and morphology of adipic acid particles precipitated by supercritical antisolvent precipitation (SAS) is investigated , An increase of the concentration of the micronized substance in the solution leads to a decrease in the particle size of adipic acid, as well as a narrowing of the particle size distribution. Depending on the solvent used and the concentration of adipic acid in the solution, it is possible to produce particles of various morphologies ranging in size from tens to hundreds of microns via SAS.
Evaluation of the Polyphenolic Content and of Acetylcholinesterase Inhibition Activity of Ginkgo biloba (Ginkgo biloba L.) Leaf Extracts Obtained in Subcritical Water
Authors: Хизриева С.С. , Борисенко С.Н. , Максименко Е.В. , Жаркова Г.В. , Борисенко Н.И. , Минкин В.И.
Published: September 2024

Впервые изучены экстракты листьев гинкго билоба (ГБ), полученные в среде субкритической воды (СБВ) в температурном интервале 100-200 °С с целью оценки перспектив их применения для профилактики и лечения нейродегенеративных нарушений, таких, например, как болезнь Альцгеймера (БА). Изучена связь содержания полифенолов и флавоноидов в экстрактах с активностью ингибирования фермента ацетилхолинэстеразы (АХЭ), которую выражали в виде значений IC (концентрация экстракта, ингибирующая фермент АХЭ на 50 %), определенных по кривым «доза-эффект». Показано, что содержание полифенолов и флавоноидов в экстрактах и их активность ингибирования АХЭ зависят от способа и условий экстракции. Максимальную ингибирующую активность АХЭ продемонстрировал экстракт, полученный в среде СБВ при 220 °С (IC = 0,74 мг/мл), при этом традиционный водно-этанольный экстракт имеет анти-АХЭ-активность IC = 3,57 мг/мл. Показано, что АХЭ-активность экстрактов листьев ГБ коррелирует с содержанием в них суммы полифенолов и флавоноидов.

The extracts of Ginkgo biloba (GB) leaves obtained in a medium of subcritical water (SBW) in the temperature range of 100 °C-220 °C were studied for the first time in order to assess the prospects for the use of GB leaf extracts for the prevention and treatment of neurodegenerative disorders, such as, for example, Alzheimer’s disease. The relationship of the activity of inhibition of the enzyme acetylcholinesterase (AChE) with the content of polyphenols and flavonoids was studied. The inhibitory activity of GB leafn extracts was expressed as IC50 values (an extract concentration that inhibits the AChE enzyme by 50 %), determined by dose-effect curves. It is shown that the content of polyphenols and flavonoids in the extracts obtained, and the inhibition activity of AChE extracts depends on the extraction method: if the traditional aqueous-ethanol extract has an anti-AChE-activity of IC = 3.57 mg/ml, then SBW- extracts are more effective inhibitors of AChE. At the same time, the maximum inhibitory activity of AChE, in a number of extracts obtained, was demonstrated by an extract obtained in the medium of SBW at 220 °C (IC50 = 0.74 mg/ml). At the same time, the AChE-activity of the obtained extracts of GB leaves correlates with the quantitative content of the sum of polyphenols and flavonoids, respectively. The total content of polyphenol (the sum of polyphenols per gallic acid or rutin) was highest in the extract obtained in medium of SBW at 220 °C, whereas the extract obtained at 100 °C in SBW was the lowest in content of polyphenols. The total content of flavonoids (in terms of rutin) was highest in extracts obtained in medium of SBW at 200-220 °C (24.6 mg equivalent to rutin/g dry weight of raw materials), and the lowest content in GB leaf extract obtained in SBW at 120 °C (10.6 mg rutin equivalent/g dry weight).
Phase Equilibrium of the Binary System «Water-Propane/Butane»
Authors: Билалов Т.Р. , Хайрутдинов В.Ф. , Хабриев И.Ш. , Гумеров Ф.М.
Published: September 2024

С использованием оптической ячейки высокого давления в интервале температуры 403-443 K и давления 5,28-20,66 МПа исследовано фазовое равновесие системы «вода-пропан/бутан» и установлен V тип фазового поведения. Растворимость воды в сверхкритической (СК) пропан/бутановой смеси в указанных условиях оценена на основе характеристик паровой ветви фазового равновесия системы «вода-пропан/бутан» и описана с использованием уравнения состояния Пенга-Робинсона в сочетании с правилом комбинирования Мухопадхъяи и Рао.

The results of an experimental study of the phase equilibrium of the «water-propane/bu-tane» system carried out in the temperature range of 403-443 K and the pressure range of 5.28-20.66 MPa using a high-pressure optical cell are presented. The V type of phase behavior is established. The solubility of water in a supercritical propane-butane mixture under the above mentioned thermodynamic conditions is estimated based on the characteristics of the steam branch of the phase equilibrium of the «water-propane/bu-tane» system and described using the Peng-Robinson equation of state in combination with the Mukhopadhyay and Rao mixing rule was made.
Extraction of Terpenes and Pigments of Juniperus Communis Tree Greenery under Suband Supercritical Conditions
Authors: Ивахнов А.Д. , Селиванова Н.В. , Красикова А.А. , Ставрианиди А.Н. , Гусакова М.А. , Боголицын К.Г.
Published: September 2024

Представлены результаты изучения эффективности выделения терпеновой фракции из древесной зелени можжевельника обыкновенного (Juniperus Communis L.) методами суб- и сверхкритической экстракции в сопоставлении с традиционными методами. Исследовано влияние параметров проведения экстракции на качественный состав экстрактов. Идентификация компонентов полученных экстрактов проведена методом хромато-масс-спектрометрии. Установлено, что качественные составы исследованных экстрактов имеют сходство, но заметно различаются количественным соотношением групп компонентов. Показано, что наибольшему извлечению монотерпенов способствуют экстракция бутаном в субкритических условиях и гидродистилляция.

The paper presents the results of studying the efficiency of the extraction of the terpene fraction from the tree greenery of common juniper (Juniperus Communis L.) by sub-and supercritical extraction methods in comparison with traditional methods. The influence of extraction parameters on the qualitative composition of extracts is studied. Identification of the components of the obtained extracts was carried out by chromatography mass spectrometry. It was found that the qualitative compositions of the studied extracts are similar, but they differ significantly in the ratio of the groups of components. It is shown that the greatest extraction of monoterpenes is facilitated by butane extraction under subcritical conditions and hydrodistillation.