Review of characteristics and analytical methods for determination of indomethacin

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the first choice of treatment for rheumatic disorders and other degenerative inflammatory diseases. One of them, indomethacin (INDO), is highlighted in this study. With its analgesic, antipyretic, and anti-inflammatory properties, it is one of the most powerful drugs used in various clinical trials and therapies related to the mechanism of blocking prostaglandin synthesis, thus reducing and eliminating many inflammatory conditions in patients. To ensure the efficacy and safety of this drug in pharmaceutical and clinical use, precise product quality control is required. Such control is performed with routine pharmaceutical analysis using various chemical methods by which INDO is identified as a separate active ingredient in the multicomponent system of a complete pharmaceutical form. In addition, the determination of INDO is important in clinical practice, where its concentration is determined in different biological samples, ensuring better monitoring of a particular therapy. The most commonly used methods for the determination of INDO are high-performance liquid chromatography (37% of developed methods), voltammetry (16% of developed methods), and UV spectroscopy (11% of developed methods). However, each of these methods must provide precise validation parameters. A combination of analytical methods can lead to more precise results and safer application in practice.

Soil genetics in its complex stabilization

The problem of the inter-repair time of automobile roads in Russia can be solved by the reinforcing the subgrade soils with cement. Soil is a multicomponent system affecting the deformation and strength properties of the composition (cement and soil). The cement-soil composition has drawbacks, especially in seasonal freezing regions, which affects its durability.In order to increase the composition efficiency, the Nicoflok polymer-mineral additive is used to strengthen subgrade with cement. However, the influence of the type regional and genetic soil on strength properties of the cement-soil + Nicoflok composition is yet studied.The paper presents the factor analysis of the influence of soil genetics on the composition strength properties. The study of the multicomponent system includes the response surface of the soil genetics on the strength properties of the composition. Additional studies are required to move from the qualitative evaluation of the soil genetics on the composition (cement-soil + Nicoflok) to the quantitative evaluation. These studies must be carried out according to a single scheme, which regards the seasonal freezing of subgrade soils in the northern regions of European Russia and West Siberia.

Influence of Individual Physical and Chemical Indices of Cognacs on their Qualitative Characteristics

Стабильность (розливостойкость) в течение длительного времени - одна из важных составляющих качественных характеристик спиртных напитков виноградного происхождения, в том числе коньяков. Коньяк представляет собой сложную многокомпонентную систему, включающую более 800 различных соединений, в том числе фенольный комплекс древесины дуба и минеральные вещества. В процессе длительного хранения под воздействием ряда факторов эти соединения, вступая во взаимодействие друг с другом, могут образовывать различные виды помутнений, что влечет за собой потерю товарного вида готовой продукции. Целью настоящей работы стало исследование влияния отдельных показателей физико-химического состава обработанных коньяков на изменение их стабильности в процессе хранения. В качестве объектов исследования использовали образцы обработанных розливостойких коньяков отечественного производства, которые были разделены в зависимости от возраста на четыре группы: I группа - 3-летние, 4-летние и 5-летние (23 образца); II группа - выдержанные «КВ» и выдержанные высшего качества «КВВК» (15 образцов); III группа - старые «КС» (9 образцов); IV группа - очень старые «ОС» (7 образцов). Образцы хранили в течение 6 мес. при температуре 22…25 °С, в условиях, не допускающих попадания прямых солнечных лучей. В процессе хранения проводили мониторинг изменения физико-химических показателей, розливостойкости и органолептических характеристик исследуемых образцов с периодичностью 1 раз в месяц. Установлено, что на всем протяжении хранения физико-химические показатели исследованных образцов оставались в пределах нормы. Однако, в отдельных образцах, на определенном этапе эксперимента (после 2 мес. хранения) было отмечено появление осадка. Кроме того, по результатам определения склонности к различным видам помутнений был отмечен рост доли коньяков, нестойких к необратимым коллоидным и кристаллическим помутнениям в трех группах, кроме IV группы. Полученные данные по исследованию структуры осадков и результаты тестов на розливостойкость согласуются с характером изменений массовых концентраций катионов натрия и кальция, а также фенольных соединений. В целом полученные результаты проведенных исследований показали необходимость контроля массовой концентрации катионов натрия и кальция, а также фенольных соединений при прогнозировании розливостойкости коньяков. One of the important components of the quality characteristics of alcoholic beverages of grape origin, including cognacs, is their stability (bottling resistance) for a long time. Cognac is a complex multicomponent system that includes more than 800 different compounds, including the phenolic complex of oak wood and minerals. During long-term storage, under the influence of a number of factors, these compounds, interacting with each other, can form various types of turbidity, which entails the loss of the presentation of the finished product. The aim of this work was to study the effect of individual indicators of the physical and chemical composition of processed cognacs on the change in their stability during storage. As objects of research, we used samples of processed bottling-resistant cognacs of domestic production, which were divided, depending on age, into four groups: Group I - three-year-old, four-year-old and five-year-old (23 samples); Group II - matured «KV» and matured of the highest quality «KVVK» (15 samples); Group III - old «KS» (9 samples); IV group - very old «OS» (7 samples). The samples were stored for 6 months at a temperature of 22…25 °C, in conditions out of direct sunlight. During storage, changes in physical and chemical parameters, bottling resistance and organoleptic characteristics of the samples under study were monitored at a frequency of 1 time per month. It was found that during the entire storage period, the physicochemical indicators of the studied samples remained within the normal range. However, in some samples, at a certain stage of the experiment (after 2 months of storage), the appearance of a precipitate was noted. In addition, according to the results of determining the tendency to various types of cloudiness, an increase in the proportion of cognacs unstable to irreversible colloidal and crystalline cloudiness was noted in three groups, except for group IV. The data obtained on the study of the structure of sediments and the results of tests for pouring resistance are consistent with the nature of changes in the mass concentrations of sodium and calcium cations, as well as phenolic compounds. In general, the results of the studies carried out showed the need to control the mass concentration of sodium and calcium cations, as well as phenolic compounds when predicting the pouring resistance of cognacs.

FORECASTING THE GROUNDWATER TREATMENT PROCESS IN A BIOREACTOR USING FERROBACTERIA

The monitoring of water quality parameters in 90 settlements of eight regions of Ukraine made it possible to state that groundwater is a complex multicomponent system. Existing deironing stations using simplified aeration-filtration technology are not able to remove Fe (II) compounds from water in the presence of humic complexes. Therefore, in modern conditions, the urgent task is to intensify their work through the introduction of new technologies, including biotechnology with the development of appropriate mathematical models. It is shown that much less attention was paid to modeling the kinetics of groundwater treatment processes in bioreactors than to traditional physicochemical methods, for which modern mathematical models were developed. The aim of the work is to develop a mathematical model of the kinetics of the process of groundwater treatment in bioreactors. The mathematical model is represented by the Cauchy problem for a nonlinear system of differential equations in partial derivatives of the first order. The system of the Cauchy problem consists of five equations with five unknown functions, which describe the distribution the concentration of ferrum cations, bacteria and the matrix structures in two phases (movable and immobilized) both in space and time. The inverse influence of the characteristics of the process, in particular, the concentration of matrix structures in the inter-pore space, as well as characteristics of the medium with the help of coefficients of mass exchange and porosity, were taken into account. The model allows determining the optimum operation time of a bioreactor between washings

Сoating of a multicomponent system Al–Cr–Ni–Co–Fe on a steel substrate obtained by laser

In recent years, the unique physical and mechanical properties of high-entropy alloys (HEAs) have been the subject of increased attention of researchers. The study of the thermodynamic characteristics of such materials may be of interest for formulating the principles of the formation of structures with the required functional characteristics. Since the processes of structure and phase formation, as well as the diffusion mobility of atoms, the mechanism for the formation of mechanical properties and thermal stability differ significantly from similar processes in traditional alloys, HEAs are singled out into a special group of materials.The article presents a brief overview of the results of obtaining a high-entropy alloy by the combined method. At the first stage, a precursor layer was deposited by сold gas dynamic spraying (CGDS), and at the second stage, it was subjected to high-energy action using a laser. An alloy of the Al-Cr-Ni-Co-Fe type has been studied. By varying the ratio of the components, it was possible to obtain an almost equimolar composition for this system. A prediction of properties and structure is made based on the phase composition of the system.

Survivability of Suddenly Loaded Arrays of Micropillars

When a multicomponent system is suddenly loaded, its capability of bearing the load depends not only on the strength of components but also on how a load released by a failed component is distributed among the remaining intact ones. Specifically, we consider an array of pillars which are located on a flat substrate and subjected to an impulsive and compressive load. Immediately after the loading, the pillars whose strengths are below the load magnitude crash. Then, loads released by these crashed pillars are transferred to and assimilated by the intact ones according to a load-sharing rule which reflects the mechanical properties of the pillars and the substrate. A sequence of bursts involving crashes and load transfers either destroys all the pillars or drives the array to a stable configuration when a smaller number of pillars sustain the applied load. By employing a fibre bundle model framework, we numerically study how the array integrity depends on sudden loading amplitudes, randomly distributed pillar strength thresholds and varying ranges of load transfer. Based on the simulation, we estimate the survivability of arrays of pillars defined as the probability of sustaining the applied load despite numerous damaged pillars. It is found that the resulting survival functions are accurately fitted by the family of complementary cumulative skew-normal distributions.

Estimation of Stress-Strength Reliability for Multicomponent System with Rayleigh Data

Inference is investigated for a multicomponent stress-strength reliability (MSR) under Type-II censoring when the latent failure times follow two-parameter Rayleigh distribution. With a context that the lifetimes of the strength and stress variables have common location parameters, maximum likelihood estimator of MSR along with the existence and uniqueness is established. The associated approximate confidence interval is provided via the asymptotic distribution theory and delta method. Meanwhile, alternative generalized pivotal quantities-based point and confidence interval estimators are also constructed for MSR. More generally, when the lifetimes of strength and stress variables follow Rayleigh distributions with unequal location parameters, likelihood and generalized pivotal-based estimators are provided for MSR as well. In addition, to compare the equivalence of different strength and stress parameters, a likelihood ratio test is provided. Finally, simulation studies and a real data example are presented for illustration.

Amphiphilic properties of humic substances in soils of the southern Vitim Plateau (Transbaikalia, Eastern Siberia)

Humic substances of soils are considered as a multicomponent system of amphiphilic (exhibiting both hydrophilic and hydrophobic properties) substances. Humic substances from soils of different genesis in the south of the Vitim Plateau (quasigley chernozem – Turbic Chernozem Molliglossic and brown soil – Stagnic Phaeozem Molliglossic) were studied. Using the hydrophobic interaction chromatography on Octyl-Sepharose® CL-4B, we separated a mixture of humic (HAs) and fulvic acids (FAs) due to their different ability to enter into hydrophobic interactions with the gel matrix. A higher percentage of hydrophobic compounds was revealed in HAs of quasigley chernozem, compared to HAs of brown soils, and FAs. The fulvic acid sample showed a lower capacity for hydrophobic interactions than the humic acid sample.

Investigation of the Quasi-Binary Phase Diagram FLiNaK-NdF3

The NdF3 solubility in molten eutectic FLiNaK, which is a conceivable medium for a molten salt reactor (MSR), was determined by the quasi-binary phase diagram FLiNaK-NdF3. The eutectic mixture FLiNaK was prepared by direct melting of components LiF, NaF and KF·HF. The acidic anhydrous salt (KF·HF) was used instead of the hygroscopic KF. The NdF3 was sintered by hydrofluorination of Nd2O3. The oxygen impurity in the prepared eutectic FLiNaK, determined by an oxygen analyzer LECO OH836, was 0.036 wt.%, whereas the NdF3 contained 0.04 wt.% of oxygen. A part of the FLiNaK-NdF3 quasi-binary phase diagram was obtained using two thermal analysis techniques: differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The FLiNaK-NdF3 phase diagram in the region of 0–30 mol.% NdF3 contains one eutectic at 2 mol.% NdF3 and 450 °C and two peritectic points: 8 mol.% NdF3 at 500 °C and 22 mol.% NdF3 at 575 °C. The region of the FLiNaK-NdF3 phase diagram below the liquidus line is rather complicated due to the complex structure of the multicomponent system in its molten state, as in its solid state. The NdF3 solubility in FLiNaK is about 5 mol.% at 490 °C and 29 mol.% at 700 °C; this means that the process of the MA transmutation in the MSR can be carried out in molten FLiNaK with a content of actinides as high as 15–20 mol.% in the temperature range of 550–650 °C.