bluuebunny/crossref_metadata_2025 huggingface dataset:
Designing, Modeling and Developing Scale Models for the Treatment of Water Contaminated with Cr (VI) through Bacterial Cellulose Biomass
Authors: Sayago Uriel Fernando Carreño , Ballesteros Vladimir Ballesteros , Aguilar Angelica Maria Lozano
Published: September 2024

The present research presents a method for scaling up a continuous treatment system with bacterial cellulose biomass for the removal of contaminants on a large industrial scale from effluents loaded with chromium (VI). This consisted of a laboratory-scale modeling process of the chromium (VI) adsorption processes, which would provide the necessary parameters to build a system on an industrial scale. The research also involved designing, modeling and developing scale models for the treatment of water contaminated with chromium (VI) through bacterial cellulose biomass. The results of the model indicated the specific route for the construction of a treatment system on an industrial scale, with the experimental data adjusted to achieve this objective. The pilot scale prototype was built using 450 g of biomass, including elution processes, with the data obtained from the aforementioned processes. In general, the excellent efficiency of the two models at different scales, together with the excellent elution results, suggests that this prototype could be presented to polluting industries for the treatment of water from different industrial effluents, being an advanced biotechnology for the treatment of industrial wastewater.
Digitalised primary care in the UK: a qualitative study of the experiences of minoritised ethnic communities
Authors: Islam Farjana , Bailey Sara , Netto Gina
Published: September 2024

Background

Barriers to accessing and using primary care services among minoritised ethnic communities have been extensively evidenced in the UK. However, the impact of the rapid digitalisation of these services on these communities remains under-researched.

Aim

To explore the impact of digitalisation on access to and use of primary care services among minoritised ethnic communities.

Design and setting

Underpinned by a critical realist intersectional approach, and employing qualitative research methods, this study explores minoritised ethnic individuals’ experiences of digital primary care in the UK.

Method

In total, 100 minoritised ethnic adults who identify as Black African, Black Caribbean, Bangladeshi, Indian, Pakistani, Chinese, and of mixed or multiple ethnic heritage in four sites in the UK were purposively recruited and interviewed. Interviews were thematically analysed to increase understanding of how individuals’ ethnicity intersects with other characteristics (for example, language, age, gender, socioeconomic status) to identify constraints and enablements to accessing health care.

Results

Minoritised ethnic individuals’ access to digital primary care is impeded by factors such as digital precarity (for example, inadequate devices, internet connectivity, and digital literacy skills), a lack of language support, and staff shortcomings in responding to ethnically diverse populations. Intergenerational support and bespoke offerings by general practices in some areas enable some individuals to overcome some of the constraints.

Conclusion

The rapid digitalisation of primary care services is replicating and potentially exacerbating barriers to using these services among minoritised ethnic communities, a finding that merits urgent attention by practitioners and policymakers.
Safety and Efficacy of Vadadustat Once Daily and Three Times Weekly in Patients With Dialysis-Dependent CKD With Anemia
Authors: Kooienga Laura , Burke Steven , Kathresal Amarnath , Luo Wenli , Yang Zhihui , Zhang Zhiqun , Zwiech Rafal , Hernandez German T.
Published: September 2024

Key Points

In this phase 3b, noninferiority trial, vadadustat once daily was noninferior to darbepoetin alfa (DA) in the correction and maintenance of hemoglobin in dialysis-dependent CKD.

Vadadustat three times weekly treatment resulted in similar changes in mean hemoglobin levels compared with vadadustat once daily, but was not noninferior to DA.

The safety profiles of vadadustat once daily and vadadustat three times weekly were comparable with that of DA.

Background

Vadadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor for treating anemia in CKD. This study investigated the safety and efficacy of once-daily and three-times-weekly dosing in patients with dialysis-dependent CKD compared with darbepoetin alfa (DA).

Methods

This phase 3b, randomized (1:1:1; vadadustat once daily [starting dose: 300 or 450 mg], vadadustat three times weekly [starting dose: 600 or 750 mg], DA), open-label, active-controlled, noninferiority trial included conversion (weeks 0–20) and maintenance (weeks 20–52) periods. Primary and secondary efficacy end points were mean change in hemoglobin from baseline during the primary evaluation period (PEP, weeks 20–26) and secondary evaluation period (weeks 46–52). Other end points included proportion of patients requiring erythropoiesis-stimulating agent (ESA) rescue (hemoglobin <9.5 g/dl or with increases in dose ≥50% or ≥100% in the DA group). Safety end points included treatment-emergent adverse events (AEs) and serious AEs.

Results

The least-squares (LS) mean treatment difference between vadadustat once daily and DA from baseline to PEP was −0.27 g/dl (95% confidence interval [CI], −0.55 to 0.01); the lower bound met the noninferiority threshold (−0.75 g/dl). The LS mean treatment difference between vadadustat three times weekly and DA from baseline to PEP was −0.53 g/dl (95% CI, −0.80 to −0.25), which did not meet the lower bound noninferiority threshold. The LS mean change from baseline to the secondary evaluation period between DA and vadadustat once daily was −0.40 (95% CI, −0.79 to −0.02) and for vadadustat three times weekly was −0.42 (95% CI, −0.81 to −0.02). The proportion of patients who received ESA rescue during weeks 2–52 was higher in the DA group than vadadustat groups. Similar treatment-emergent AEs and treatment-emergent serious AEs were observed across groups.

Conclusions

Vadadustat once daily, but not three times weekly, was noninferior to DA in the correction and maintenance of hemoglobin in patients with dialysis-dependent CKD converted from an ESA; safety profiles were similar across groups.

Clinical Trial registry name and registration number:

EudraCT 2019-004851-36/ClinicalTrials.gov identifier: NCT04313153.
An Examination Of Irish Females Attitudes Towards Nanotechnology Claims Used In Advertising Appeals By The Cosmetics Industry
Authors:   ,   Cork Institute of Technology, Kelleher Deirdre
Published: September 2024

"Cosmetics advertising exert an image of hope and belief to consumers in that these products will dramatically make them look younger and change their lives. Much criticism has been drawn to cosmetic claims based on nanotechnology. Do they work? Are they safe? Do the cosmetic companies use false claims? Today, the media is saturated with advertisements that promote cosmetic products. The cosmetics industry is becoming more and more advanced due to the use of nanotechnology. Cosmetic advertisements are so common that it is difficult to distinguish one from the other. Celebrity endorsers are being utilised by cosmetic companies to promote nanotechnology based cosmetic products, free sampling is also a popular method used as a marketing tool. There are some concerns surrounding the use of nanotechnology in cosmetics. Concern exist also on the reliability of cosmetics advertisements due to false claims that have emerged from companies such as L’Oreal. This study seeks to examine the attitudes that Irish female consumers have concerning the use of nanotechnology claims in cosmetic advertising. Respondents gave their views on the various areas surrounding the use of nanotechnology is cosmetics advertising appeals including; Celebrity endorsers, free samples, false claims, influence on purchase, preferences on nanotechnology claims versus natural claims and documentary style advertisements. The respondents views were analysed in different age groups to seek how women’s’ attitudes change with age. It has been shown from the research that the use of nanotechnology in cosmetics advertising such as anti-wrinkle creams did have a positive effect on most of the respondents in the study. It was noted that there is too much scientific jargon used in these advertisements, however it does not affect the consumers decision in a negative way. It emerged that cosmetic advertising did have a positive effect on the purchasing decision of a consumer. The findings of this research are significant as they expose female consumers’ attitudes towards the advertising of nanotechnology based claims in cosmetics."
Voltage Rise Mitigation In A Weak Distribution Network Due To The Impact Of Distributed Generation
Authors:   ,   Cork Institute of Technology, Caples Donal
Published: September 2024

"There are numerous aspects of a distribution network that must be studied in order to determine the maximum size of distributed generation that can be accommodated on the distribution network before supply standards are breached. Voltage rise is one of the main aspects of concern when connecting a distributed generator to a distribution network and this thesis develops the understanding of this phenomenon and concludes with a real life study. Mathematical and computer simulation software examples within this thesis demonstrate how voltage rise can be reduced to the maximum allowable limit, a major concern if the capacity of a distributed generator unit is greater than the local load demand capacity of the feeder it is connected to, which is often the case especially with weak rural networks. The thesis assesses the various options a distribution system operator planner has available to them when determining the least cost technically acceptable method for reducing voltage rise to an acceptable level. Some methods of voltage rise mitigation discussed in this thesis are not approved methods in Ireland although they are discussed and analysed in many technical publications. The thesis concludes with a study of a voltage rise that is caused by the introduction of a distributed generator unit exporting onto a 38 kV feeder in Ireland. Each option is studied and discussed and the findings of these technically acceptable options are ranked from a distribution system operator’s point of view. The financial assessment of these options is based on the agreed Commission for Energy Regulation costs with the Distribution System Operator in 2008. The overall results are then ranked by the criteria of least cost technically acceptable. This is the option that is then presented to the independent power producer. The independent power producer must assess this solution from financial cost, planning permission acquirement and length of project completion perspectives."
Ultra Wideband Pulse Shaping
Authors:   ,   Cork Institute of Technology, Rulikowski Pawel
Published: September 2024

"Methods for shaping of sophisticated, transient, ultra wideband (UWB) waveforms and pulses are presented. The methods include novel circuits based on step recovery diodes (SRDs) and quasi-transversal filter concepts but the majority of the work focuses on UWB pulse shaping using completely passive nonuniform transmission lines (NUTLs). It is shown, for the first time, that NUTLs can be used to generate highly sophisticated arbitrary UWB pulse shapes, including modified Hermite polynomial (MHP) and approximate spheroidal wave function (APSWF) pulses which are not known to have been previously generated in practice, and a generalized methodology, verified by experiments, for design of NUTLs for UWB pulse shaping is presented. Also, a verified methodology for compensating for wideband loss and dispersion in NUTLs is demonstrated, believed to be the first time this has been achieved. An extensive literature review demonstrates the need for more sophisticated UWB pulse shapes than can be generated using currently available approaches. The review examines these current approaches and, in particular, presents the state of the art in NUTL design and synthesis and in methods for compensating for NUTL non-idealities. It establishes that while NUTLs have the potential to be used for UWB pulse shaping, this has not been previously reported and that no satisfactory method for compensation for loss and dispersion in NUTLs exists. Novel active circuits for UWB pulse shaping using SRD and quasi-transversal filter concepts are presented but these are shown to be limited in both the range and complexity of UWB pulses that can be generated. To overcome this, the development and verification are described of a novel methodology, assuming loss-free and dispersion-free lines, for synthesis of NUTLs capable of generating arbitrary UWB pulse shapes, including MHP and APSWF pulses which have previously only been described in theory. This methodology is then further extended to the first known verified methodology for compensation for the loss and dispersion that exist in practical NUTL. The scope of this last methodology has far greater applications than UWB as it is very general in its nature and its methodologies and techniques can be applied to the characterisation of non-uniform, one dimensional propagation inverse problems in known media e.g. transmission lines with known frequency-dependent propagation parameters and can also find use in, say, geology and acoustics."
Ethics Of Using Product Samples As A Public Relations Tactic In The Blogosphere.
Authors:   ,   Cork Institute of Technology, Chesne Catherine
Published: September 2024

"Public relations used to be only concerned with traditional media but with the rise of new media and new trends in communication there has been a shift in the public relations media environment. This study aims to look at the ethics of using product samples as public relations tactic in the blogosphere. A qualitative research design was chosen, and semi structured and online interviews were used to carry out primary data collection. Interviewees were selected from both public relations and blogging backgrounds, to get a full understanding into their insight and experience of the research topic. The research findings show that the blogosphere has become a new media platform for practicing public relations but it hasn‘t been embraced by all practitioners, and that the use product samples is ethical. The use of product samples have both advantages and disadvantages as a public relations tactic, and using them in the blogosphere is leading to the creation of new media relations, which are being used to spread the messages of public relations."
ANALYSIS OF LOW ORBIT SATELLITE BROADBAND ACCESS SYSTEMS USING THE EXAMPLE OF STARLINK DEVELOPMENT
Authors: Урличич Ю.М.
Published: September 2024

Представлены оценки требуемого угла сканирования активной фазированной антенной решётки (АФАР) абонентского терминала системы Starlink и потенциала снижения его себестоимости в зависимости от «мощности» орбитальной группировки спутниковой системы широкополосного доступа. Показано, что имеется возможность существенного снижения себестоимости абонентского терминала, если численность КА в орбитальной группировке достигнет нескольких десятков тысяч. Приведен анализ темпов наращивания орбитальной группировки и абонентской базы системы Starlink. Результаты анализа показывают значительное отставание от планов, намеченных в бизнес-модели Starlink, нецелесообразность создания коммерческих низкоорбитальных спутниковых систем широкополосного доступа для решения задачи массового обслуживания и необходимость поиска новых системных решений, в частности создания систем прямого спутникового доступа типа Direct-to-Device.

Estimates of the required scanning angle of the active phased array of the Starlink user terminal and the potential for reducing its cost depending on the number of satellites in the orbital constellation of the satellite broadband access system are presented. It is shown that it is possible to significantly reduce the cost of a user terminal if the number of satellites in the orbital constellation reaches several tens of thousands. An analysis of the pace of growth of the orbital constellation and the subscriber base of the Starlink system is presented. The results of the analysis show a significant delay from the plans outlined in the Starlink business model, the inexpediency of creating commercial low-orbit satellite broadband access systems to solve the problem of queuing, and the need to find new system solutions, in particular the creation of direct-to-device type systems.
RESEARCH OF LATENT SPACE QUANTIZATION METHODS OF VARIATIONAL AUTOENCODER FOR FPV VIDEO STREAM FRAMES. PART II
Authors: Березкин А.А. , Ченский А.А. , Вивчарь Р.М. , Киричек Р.В.
Published: September 2024

Одним из путей повышения эффективности работы мобильных и гибридных орбитально-наземных сетей связи, используемых для передачи кадров видеопотока при управлении беспилотными воздушными судами (БВС) в режиме от первого лица, является уменьшение требуемой полосы пропускания для каждого БВС, что требует обеспечения высокой степени сжатия кадров при сохранении их качества. Для решения этой задачи используются методы, основанные на применении вариационных автокодировщиков, которые производят кодирование кадров в латентное пространство признаков нейронной сети, квантование и сжатие без потерь. Во второй части этой статьи представлены результаты исследований оценки влияния применения различных алгоритмов квантования на степень сжатия латентного пространства признаков вариационного автокодировщика VQ-VAE-f16 из состава моделей Stable Diffusion методов сжатия без потерь с помощью алгоритма LZMA. Даны рекомендации по использованию наиболее эффективных алгоритмов квантования при их совместном использовании с алгоритмами сжатия без потерь.

One of the ways to improve the efficiency of mobile and hybrid orbital-terrestrial communication networks used to transmit video stream frames when controlling unmanned aerial vehicles (UAVs) in first person view (FPV) mode is to reduce the required bandwidth for each UAV. This requires ensuring a high degree of frame compression while maintaining their quality. To solve this problem, methods based on the application of variational autoencoders that perform frame encoding into the latent feature space of the neural network, quantization and lossless compression are used. In the second part of this paper the results of estimation of influence of applying different quantization algorithms on the latent space compression ratio of VQVAE-f16 variational autoencoder from the composition of Stable Diffusion models of lossless compression methods with the help of LZMA algorithm are presented. Recommendations are given on the use of the most effective quantization algorithms when they are used together with lossless compression algorithms.
INTERFACE FOR METAVERSE INTERACTION
Authors: Волков А.Н.
Published: September 2024

Исследован один из методов взаимодействия с метавселенной (мультивселенной) и ее объектами – костюм телеприсутствия. Приведена модель костюма телеприсутствия, описывающая процесс формирования данных состояния и их передачи в точку назначения, в качестве которой может выступать робот-аватар или виртуальная копия. Проанализированы основные характеристики типовых сигналов, формируемых датчиками костюма телеприсутствия. Дано определение ошибки, вносимой процессами преобразования и передачи сигналов, и сформулирована задача минимизации вносимой ошибки. В работе также определена задача выбора разрядности аналого-цифровых преобразователей костюма телеприсутствия как задача оптимизации условных издержек, обусловленных вносимой ошибкой. Предложенный метод позволяет повысить эффективность решения задач управления за счет уменьшения ошибок наиболее значимых сигналов.

The article provides research on one of the interfaces for interaction with the metaverse (multiverse) and its objects – a telepresence suit. The work provides a model of a telepresence suit that describes the process of generating state data and transmitting it to a destination point, which can be a robot avatar or a virtual replica. The paper provides an analysis of the main characteristics of typical signals generated by the suit’s sensors. The definition of the error introduced by signal conversion and transmission processes is given, and the problem of minimizing the introduced error is formulated. The work also formulates the problem of selecting the bit capacity of analog-to-digital converters of a telepresence suit as a problem of optimizing conditional costs caused by the introduced error. The proposed method makes it possible to increase the efficiency of solving control problems by reducing the errors of the most significant signals.
GENERALIZED MODEL OF THE LIGHT PATH IN OPTICAL TRANSPORT NETWORKS BASED ON RECONFIGURABLE OPTICAL INPUT/OUTPUT MULTIPLEXERS
Authors: Ясинский С.А. , Бойко А.П. , Одоевский С.М.
Published: September 2024

В статье дано строгое определение световому пути. Понятие светового пути расширено и уточнено за счёт объединения маршрута прохождения сигнала и назначенной полосы частот. Свойства и требования к световым путям выражены в терминах элементарных частотных интервалов, на которые разделен спектр в гибких оптических сетях, что позволяет упростить некоторые вычисления, связанные с проверкой на пригодность. Предложена метрика качества светового пути в закрытой форме, на основе которой формируется множество допустимых световых путей, учитывающая виды передаваемых сигналов. Представлен ряд возможных критериев оптимальности для решения задач поиска и распределения световых путей.

The article gives a strict definition of the light path. The concept of the light path has been expanded and clarified by combining the signal path and the assigned frequency band. The properties and requirements for light paths are expressed in terms of elementary frequency intervals into which the spectrum is divided in flexible optical networks, which makes it possible to simplify some calculations related to the suitability test. A light path quality metric is proposed that takes into account linear signals in a closed form, on the basis of which a set of acceptable light paths is formed. A number of possible optimality criteria for solving the problems of the search and distribution of light paths are presented.
EPR Diagnostics of Porous Matrixeson the Basis of D,L-Polylactide, Generated in the Mediumof Supercritical СО
Authors: Чумакова Н.А. , Голубева Е.Н. , Иванова Т.А. , Воробьева Н.Н. , Тимашев П.С. , Баграташвили В.Н.
Published: September 2024

Методы электронного парамагнитного резонанса (ЭПР) в варианте методикиспинового зонда и оптической микроскопии были использованы для установления закономерностей формирования пористых матриксов на основе D,L-полилактида в среде сверхкритического СО2 с одновременной импрегнациейпарамагнитным биологически активным веществом 4-гидрокси-2,2,6, 6-тетраме-тилпиперидин-1-оксидом (ТЕМПОЛ). Сделаны оценки зависимости средней илокальной концентрации допанта от условий импрегнации. Показано, что полученные матриксы отвечают ряду важнейших требований, предъявляемых к пористым материалам для тканевой инженерии. Поскольку импрегнация полимерапарамагнитным соединением дает возможность изучать равномерность распределения допанта в образце на макроскопическом и микроскопическом уровнях,а также судить о структуре полимерной матрицы, спектроскопия ЭПР являетсяперспективным методом исследования пористых полимерных материалов, сформированных в сверхкритических условиях.

The spin probe technique as a version of the electron paramagnetic resonance (EPR)spectroscopy was used to reveal the regularities of the formation of porous matrixesbased on D,L-polylactide in a supercritical CО medium with the simultaneousimpregnation by paramagnetic biologically active test molecule 4-Hydroxy-2,2,6,6-tetra-methylpiperidine 1-oxyl (TEMPOL). The dependences of the average and local dopantconcentration on impregnation conditions were estimated. It was concluded that EPRspectroscopy is a promising method for studying porous polymeric materials formedin supercritical conditions. Impregnation of the polymer with a paramagnetic compoundallows one to estimate the uniformity of the dopant distribution in a sample on bothmacroscopic and microscopic levels, and also to judge the structure of the polymermatrix. The data obtained by EPR and optical spectroscopy showed that the resultingmatrixes meet the important requirements for porous materials for tissue engineering.
DEVELOPMENT OF ONE-STEP («ONE-POT») TECHNIQUE FOR PRODUCTION OF QUERCETIN ANTIOXIDANT FROM SOPHORA JAPONICA L. BUDS IN SUBCRITICAL WATER MEDIUM
Authors: Максименко Е.В. , Лекарь А.В. , Борисенко С.Н. , Хизриева С.С. , Ветрова Е.В. , Борисенко Н.И. , Минкин В.И.
Published: September 2024

Исследована возможность получения природного антиоксиданта - кверцетина из бутонов софоры японской (Sophora japonica L.) с использованием субкритической воды, которая служит одновременно реагентом и растворителем. Предложенный подход позволяет избежать использования дорогостоящих токсичных органических растворителей, не требует проведения раздельных стадий экстракции и гидролиза и упрощает очистку продукта. Высокие выходы кверцетина получены за время в 13 раз меньшее, чем требуется при использовании традиционной методики. Снижены потери целевого продукта при получении сухого экстракта.

The possibility of obtaining quercetin (a natural antioxidant) from buds of Sophora japonica L. using subcritical water, which acts as a solvent and a reagent simultaneously was studied. The suggested approach avoids the use of expensive and toxic organic solvents, does not require separate extraction and hydrolysis steps and simplifies the purification of the product. A 13-fold reduction in treatment time was achieved compared with the traditional procedure to obtain high yield of quercetin. The loss of the target product in the production of the dried extract was reduced.
SYNTHESIS OF BIMETALLIC CATALYST IN A STATIC CO-IMPREGNATION PROCESS
Authors: Билалов Т.Р. , Гумеров Ф.М. , Габитов Ф.Р.
Published: September 2024

Исследован синтез палладиевого и палладий-серебряного катализаторов с использованием сверхкритического флюидного СO-импрегнационного процесса (статический режим). Показано, что максимальное количество металла импрегнируется на носитель в интервале температур 318-323 К и диапазоне давлений 19,0- 23,0 МПа. Активность приготовленных по предложенной методике палладиевых катализаторов сопоставима с активностью выпускаемых в настоящее время промышленных образцов.

The synthesis of palladium and palladium-silver catalysts using supercritical fluid C0-impregnation process (static mode) was investigated. It is shown that the maximum amount of metal is impregnated to the carrier in the temperature range 318-323 K and pressure range 19.0-23.0 MPa. The activity of palladium catalysts prepared according to the proposed method is comparable with the activity of industrial samples currently produced.
Supercritical Carbon Dioxide - a Powerful Tool for Green Biomaterial Chemistry (review)
Authors: Верясова Н.Н. , Лажко А.Э. , Исаев Д.Э. , Гребеник Е.А. , Тимашев П.С.
Published: September 2024

Описаны ключевые особенности модификации биосовместимых материалов в среде câepxкpитичecкoгo диоксида углерода (СК-СО) и ocнoвныe тенденции в применении описанного метода для получения трехмерных структур, стерилизации изделий медицинского назначения, децеллюляризации тканей млекопитающих и импрегнации матepиалoв биологически активными молекулами. Благодаря неразрушающему вoздeйcтвию среды СК-СО на архитектонику внe клеточного матрикса, сохранению механических свойств и структуры обрабатываемых мате-pиалoв, oтcутcтвию необходимости постобработки и очистки cфopмиpoванныx матриц, пpeдcтaвлeнный метод можно рассматривать как универсальный подход к решению наиболее актуальных задач биомедицинского матepиалoвeдeния.

In the review, the key aspects to the modification of biocompatible materials are described based on treatment in supercritical carbon dioxide medium. Main trends in the area include the fabrication of three-dimensional scaffolds, sterilization of medical devices, mammalian tissue decellularization and material impregnation with bio-active molecules. Due to non-destructive action of the supercritical carbon dioxide medium towards extracellular matrix’s architecture, preservation of inherent biomechanical properties and structure of treated biomaterials, avoidance of purification and postprocessing steps, the technique is considered as a powerful tool to solve the urgent issues of biomaterials science.
Spin Probe Method for Diagnostics of Polyster Porous Matrixes Formed in Supercritical Carbon Dioxide (review)
Authors: Голубева Е.Н. , Чумакова Н.А.
Published: September 2024

Обзор посвящен исследованию методом электронного парамагнитного резонанса (ЭПР) пористых полимерных материалов (матриксов), полученных из алифатических полиэфиров и допированных парамагнитными биологически активными веществами с помощью сверхкритических флюидных технологий. Особое внимание уделяется возможностям ЭПР-спектроскопии для установления закономерностей процессов формирования матриксов, последующей характеризации полученных материалов, а также особенностей высвобождения допантов в водные растворы in vitro.

The review is devoted to the electron paramagnetic resonance (EPR) studies of porous polymer materials (matrixes) obtained from aliphatic polyesters and doped with paramagnetic biologically active substances by means of supercritical fluid technologies. Particular attention is paid to the possibilities of the EPR-spectroscopy for establishing the regularities of the formation of the matrixes, the subsequent characterization of the materials obtained, and also the features of the dopant release to aqueous solutions in vitro.
Supercritical Fluid Extraction of Petroleum Products and Tar-Asphaltene Mixtures from High-Watercut Oil Sludges
Authors: Хайрутдинов В.Ф. , Габитова А.Р. , Гумеров Ф.М. , Габитов Р.Ф. , Курдюков А.И.
Published: September 2024

Исследована возможность выделения нефтепродуктов из нефтяных шламов с использованием процессов жидкостной и сверхкритической флюидной экстракции. Исходный нефтешлам содержит (здесь и далее - в мас. %) 30 воды, 5,9 механических примесей и 5,7 асфальтенов. Экстракция смесью пропана и бутана в соотношении 3 : 1 (мас. %) при 85-120 °С и давлениях 10 и 15 МПа позволяет получить нефтепродукты с существенно пониженными вязкостью и содержанием серы и воды.

The possibility of extracting petroleum products from oil sludges using liquid and supercritical fluid extraction is studied. The initial content of water and solid residues in the sludge sample was 30 and 5.9 wt. %, respectively. If the 3: 1 (by weight) propane-butane mixture is used as extragent at 85-120 °С and 10-15 MPa, the petroleum product with substantially reduced viscosity and sulfur and water content can be obtained.
Nitrolysis of Cyclic Polyacylamines in Liquid Carbon Dioxide and 1,1,1,2-Tetrafluorethane Media
Authors: Жарков М.Н. , Кучуров И.В. , Суханова А.А. , Фоменков И.В. , Злотин С.Г.
Published: September 2024

Нитролизом 1,3-диацетилимидазолидина и 1,3-диацетилгексагидропиримидина под действием оксида азота(V) в среде сжиженных газов (диоксид углерода или 1,1,1,2-тетрафторэтан) получены соответствующие циклические бис-нитрамины. Нитролиз 1,3,5-триацетил-1,3,5-триазациклогексана и 1,3,5,7-тетраацетил-1,3,5,7-тетраазациклооктана в аналогичных условиях протекает неселективно, давая смесь продуктов неполного нитрования.

Nitrolysis of 1,3-diacetylimidezolidine и 1,3-diacetylhexahydropyrimidine with nitrogen oxide(V) in liquid gases (carbon dioxide or 1,1,1,2-tetrafluoroethane) afforded corresponding cyclic bis-nitramines. Nitrolysis of 1,3,5-triacetyl-1,3,5-triazacyclohexane and 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane proceeded under similar conditions in a nonselective manner to give mixtures of incomplete nitration products.
Quas-Adiabatic Expansion of the Polylactide Foam: Features of the Porous Matrices Formation in the Region of Transition Between Suband Supercritical States of Plasticizing Carbon Dioxide
Authors: Зимняков Д. А. , Баграташвили В. Н. , Ювченко С. А. , Славнецков И.О. , Калачева А.В. , Ушакова О.В.
Published: September 2024

Представлены экспериментальные данные о динамике квази-адиабатического расширения пены, формируемой на основе CO-пластифицированного полилактида при быстром сбросе давления пластифицирующего агента. Показано, что в интервале начальных значений давления агента, соответствующем переходу между его суб- и сверхкритическим состояниями, имеет место существенное увеличение конечного объема синтезируемых пористых матриц. Исследование структуры синтезированных матриц на мезоскопическом уровне с использованием низкокогерентной рефлектометрии показало кардинальные отличия по сравнению с режимами синтеза с существенным отклонением начального давления от области перехода как в большую, так и в меньшую сторону. Наблюдаемые особенности интерпретированы с использованием качественной модели, основанной на уравнении состояния Росса и учитывающей знак инкремента удельной внутренней энергии пластифицирующего и вспенивающего агента при переходе из начального в конечное термодинамическое состояние вспениваемого полимера.

Experimental data on the dynamics of quasi-adiabatic expansion of the foam, which is formed on the base of carbon-dioxide-plasticized polylactide in the course of fast depressurization, are presented. It is shown that, in the range of initial pressure, which corresponds to the region of transition between the subcritical and supercritical states of plasticizing agent, the substantial increase in the resulting volume of the formed porous matrices takes place. Study of the structure of synthesized matrices at the mesoscopic level provided using the low-coherence reflectometry showed the dramatic difference in comparison with the synthesis conditions far from the transition region. The observed features are interpreted in the framework of a qualitative model based on the equation of foam state proposed by Ross. The considered model takes into account the sign of increment of the internal energy of a plasticizing and foaming agent in the course of transition between the initial and final thermodynamics states of the foamed polymer.
Conjugated Processes of Heterogeneous-Homogeneous Oxidation of Hydrogen in High-Density H/O/HO, H/O/CO and H/O/N Mixtures
Authors: Востриков А.А. , Федяева О.Н. , Шишкин А.В. , Сокол М.Я.
Published: September 2024

Впервые исследованы особенности горения водорода в его стехиометрических смесях с кислородом при высоком давлении (~2,6 МПа) в среде водяного пара, диоксида углерода и азота в трубчатом реакторе из нержавеющей стали при его равномерном медленном нагреве (1 K/мин). Зафиксировано возникновение сопряжения гетерогенного (на стенке реактора) и гомогенного (в объеме реакционной смеси) окисления водорода. Гетерогенное окисление Н доминировало в среде N и CO, а гомогенное - в среде HO. Исходя из временных зависимостей прироста температуры, вызванного тепловыделением при окислении водорода, установлено, что температура самовоспламенения смесей H/O/N и Н/O/Н0 примерно на 30 K ниже, чем смеси Н/O/СO. Показано, что небольшая добавка воды уменьшает температуру самовоспламенения смесей H/O/N и H/O/CO.

The peculiarities of hydrogen combustion in its stoichiometric mixtures with oxygen diluted with water vapor, carbon dioxide, and nitrogen at ~2.6 MPa is investigated for the first time. The experiments were carried out at slow uniform heating (1 K/min) in a tubular stainless steel reactor in which the process occurs via the conjugate heterogeneous (over the reactor wall) and homogeneous (in the volume of the reaction mixture) oxidation reactions. Heterogeneous oxidation of H prevailed in the N and CO media, while homogeneous oxidation was predominant in the HO medium. Based on time dependencies of temperature rise caused by the exothermic oxidation of hydrogen, it is found that the self-ignition temperature of H/O/N and H/O/HO mixtures is by about 30 K lower than that of the Н/O/СO mixture. It is shown that a small addition of water to the H/O/N and H/O/CO mixtures leads to a decrease in the self-ignition temperature.
Comparative Analysis of Lignin and Sludge-Lignin Oxidation in the Stream of Air and Water-Oxygen Mixture
Authors: Федяева О.Н. , Востриков А.А.
Published: September 2024

Представлены результаты исследования окисления сульфатного лигнина и шлам-лигнина (отходы Байкальского целлюлозно-бумажного комбината) в потоке воздуха и водокислородной смеси при равномерном повышении температуры. Исходя из временных зависимостей мощности омических нагревателей и температуры стенки реактора установлено, что максимальная скорость окисления лигнина и шлам-лигнина в смеси Н0/0 достигается при 613-643 K. Окисление обоих образцов в смеси Н0/0 завершается при более низкой температуре, чем в воздушной среде. Получены температурные зависимости выхода летучих и жидких продуктов, включая фенолы. Методом масс-спектрометрии показано, что 90,3 и 79,5 % углерода лигнина и шлам-лигнина, соответственно, при их окислении в потоке Н0/0 превращается в С0 и СО. Обсуждаются механизмы превращения гетероатомных компонентов. Образование соляной и серной кислот при окислении шлам-лигнина в потоке Н0/0 вызывает коррозию нержавеющей стали.

Oxidation of sulfate lignin and sludge-lignin (waste of the Baikal Pulp and Paper Mill) in the stream of water-oxygen mixture and in air in the programmed heating regime is studied. Based on the temporal dependences of the power of resistive heaters and the reactor wall temperature, it was revealed that the maximum rates of lignin and sludge-lignin oxidation in the HO/O mixture are reached at 613-643 K. Oxidation of both substances in the HO/O mixture is completed at lower temperatures than in air. The temperature dependences of compositions of volatile and liquid products, including the content of phenols, are obtained. Using the mass-spectrometric analysis it is shown that during oxidation in the HO/O stream 90.3 and 79.5 % of carbon is removed from lignin and sludge-lignin, respectively, in the form of carbon oxides. The mechanisms of transformation of heteroatomic components are discussed. Formation of hydrochloric and sulfuric acids in the course of sludge-lignin oxidation in the HO/O stream causes the corrosion of stainless steel.
Preparative Separation Method Development of Salbutamol Enantiomers by Supercritical Fluid Chromatography
Authors: Микушина И.В. , Царев В.Н. , Базарнова Н.Г. , Чепрасова М.Ю. , Сысоева А.В. , Сысоев А.В. , Кушнир Е.Ю. , Геньш К.В.
Published: September 2024

В работе представлены результаты масштабирования аналитической методики сверхкритического хирального разделения сальбутамола до препаративного масштаба. Определены условия хроматографирования, разработана методика препаративного разделения энантиомеров методом сверхкритической флюидной хроматографии, при которых содержание R-изомера сальбутамола (энантиомерная чистота) составляет не менее 90 %, выход целевого продукта более 30 %.

The paper presents the results of scaling up the supercritical chiral separation of salbutamol to a preparative scale. Chromatographic conditions have been determined, a technique for preparative separation of enantiomers by supercritical fluid chromatography has been developed, in which the content of the R-isomer of salbutamol (enantiomeric purity) is not less than 90 %, the yield of the target product is more than 30 %.
Structuring and Phase Formation in Silica Gel in Water Fluids of Different Densities
Authors: Лагунова Е.А. , Ивакин Ю.Д. , Синёв М.Ю. , Шашкин Д.П. , Фаттахова З.Т. , Гордиенко Ю.А.
Published: September 2024

Исследовано влияние плотности водного флюида в диапазоне ~10- 0,25 г/см на структурирование аморфного силикагеля при 380 °С - температуре выше критической точки воды. Показано, что снижение величины удельной площади поверхности (5у) силикагеля наблюдается уже при наименьшей плотности; при ее возрастании происходит дальнейшее снижение 5у, а начиная с величины плотности ~ 0,01 г/см в образце наблюдается образование кристаллических фаз кремнезема (кристобалит, китит). На основании наблюдаемых закономерностей изменения морфологии и кристалличности SiO, а также анализа данных по изменению свойств водного флюида при варьировании температуры и давления ниже и выше критической точки сделан вывод о том, что возрастание скорости структурирования с ростом плотности водного флюида связано скорее с кинетическим фактором (закон действующих масс), чем с изменением физического состояния воды (действие сил межмолекулярного взаимодействия). Использование полученных образцов обработанного силикагеля в качестве носителя катализатора NaWMn/SiO для реакции окислительной конденсации метана показало, что эффективность катализатора снижается с ростом степени кристалличности носителя. Однако при использовании носителей, прошедших обработку при относительно низких плотностях водного флюида (< 0,05 г/см) катализатор более активен и селективен, чем при использовании исходного силикагеля.

The effect of the density of water fluid in the range of ~10-0.25 g/cm on the structuring of amorphous silica gel was studied at 380 °C that exceeds the temperature of critical point of water. It is shown that a decrease in the specific surface area (S) is already observed at the lowest density; as the latter increases, S decreases further, and starting from a density of ~0.01 g/cm, the formation of crystalline silica phases (cristobalite, keatit) is observed in the sample. Based on the observed regularities in the change in the morphology and crystallinity of SiO, as well as the analysis of data on the variations in the properties of the water fluid with temperature and pressure below and above the critical point, it was concluded that the increase in the structuring rate with an increase in the density of the aqueous fluid is more likely due to the kinetic factor (mass action law) than with a change in the physical state of water (intermolecular interaction forces action). Using the obtained samples of treated silica gel as a support for the NaWMn/SiO catalyst for the oxidative coupling of methane it was shown that the efficiency of the catalyst decreases with increasing degree of crystallinity of the support. However, when using supports that have undergone processing at relatively low densities of water fluid (< 0.05 g/cm), the catalysts are more active and selective than the one supported on the initial silica gel.
Composition and Antimicrobial Activity of Essential Oil and Supercritical Extracts of Pmus Sylvestris Wood Greenery
Authors: Селиванова Н.Б. , Красикова А.А. , Гусакова М.А. , Боголицын К.Г. , Ивахнов А.Д.
Published: September 2024

Проведен сопоставительный анализ влияния способов экстракции, отвечающих принципам «зеленой химии», на степень выделения компонентов из древесной зелени сосны обыкновенной (Pinus sylvestris). Методом ГХ-МС при анализе спиртового экстракта, эфирного масла и сверхкритических экстрактов показаны их различия, как в количественном, так и качественном составе. Установлена наибольшая селективность выделения фракции дитерпенов, а также расширение спектра извлекаемых индивидуальных компонентов из древесной зелени методом сверхкритической флюидной экстракции диоксидом углерода (по сравнению с традиционными методами экстракции) при сохранении высокой антимикробной активности полученного экстракта на подавление штаммов Escherichia coli.

The paper presents a comparative analysis of influence of extraction methods that meet the principles of «green chemistry» on the extraction degree of components from the wood greenery of Pinus sylvestris. Analysis of the obtained alcohol extract, essential oil and supercritical extracts by GC-MS method showed that differences are observed in both the quantitative and qualitative composition of the studied objects. The highest selectivity of the diterpene fraction extraction and the expansion of the spectrum of individual components extracted from wood greenery by supercritical fluid extraction with carbon dioxide compared to traditional extraction methods while maintaining a high antimicrobial activity of the resulting extract to suppress Escherichia coli strains is shown.
Efficiency of Hydrothermal Processing of Organic Waste in a Full Mixed Flow Type Reactor
Authors: Федотов А.В.
Published: September 2024

Показана эффективность переработки органических жидких и твердых отходов агропромышленного комплекса (АПК) в процессе окисления в сверхкритических условиях (СК-условиях), конверсия составляет не менее 99,7 %. Установлена зависимость между объемом реактора непрерывного действия и содержанием органических веществ. Высокие скорости окисления отходов в СК-условиях позволяют достичь производительности около 100 кг отходов в час при объеме реактора 100-140 л. Теплонапряженность реактора может составлять 730 кВт/м.

The efficiency of processing organic liquid and solid wastes of the agro-industrial complex in supercritical conditions is shown. The conversion is at least 99,7 %. The dependence of the volume of a continuous reactor on the content of organic substances has been established. High rates of oxidation of waste in supercritical conditions make it possible to reduce the volume of the reactor (up to 100-140 l) with a capacity of up to 100 kg of waste per hour. The heat density of the reactor can reach 730 kW/m
Comparative Study of Levofloxacin Solubility in Supercritical Carbon Dioxide and Trifluoromethane
Authors: Антонов Е.Н. , Кротова Л.И. , Мишаков Г.В. , Попов В.К.
Published: September 2024

Измерена растворимость левофлоксацина (ЛФЦ) в сверхкритических диоксиде углерода и трифторметане в диапазоне давлений 10-30 МПа при температуре 323 и 373 К. Растворимость определялась по изменению массы навески ЛФЦ, выдерживаемой в СК-флюиде при заданных температуре и давлении. Полученное значение растворимости ЛФЦ в СК-трифторметане при давлении 30 МПа и температуре 323 К практически на порядок превышает растворимость в СК-диоксиде углерода при тех же условиях - (5,6 + 0,3) • 10 мольных долей против (5,9 + 0,3) • 10 мольных долей. При давлении 30 МПа и температуре 373 К растворимость ЛФЦ в СК-трифторметане достигает значения (8,3 + 0,3) • 10 мольных долей. Полученные результаты являются основанием для дальнейшей разработки и оптимизации процессов СКФ-микронизации различных антибиотиков группы фторхинолонов без участия жидкого сорастворителя.

The solubility of levofloxacin (LFC) in supercritical carbon dioxide and trifluoromethane was measured in the pressure range 10-30 MPa at temperatures of 323 K and 373 K. Solubility was determined by changing the weight of the LFC powder held in the supercritical fluid (SC) at given temperature and pressure. The obtained solubility value of LFC in SC-trifluoromethane reaches a value (8.3 ± 0.3) • 10 mole fractions at 30 MPa and 373 K. Solubility of LFC in SC-trifluoromethane at a pressure of 30 MPa and a temperature of 323 K ((55.7 ± 0.3) • 10 mole fractions), almost by an order of magnitude exceeds the solubility in SC carbon dioxide ((5.9 ± 0.3) • 10 under the same conditions. The obtained results are the basis for further development and optimization of processes of supercritical fluid micronization of LFC and other antibiotics of fluoroquinolone group without participation of liquid co-solvent.