Using reference materials of blast furnace slag, steelmaking slag, converter slag and fused fluxes when developing a procedure for analysis of slag-forming mixtures using inductively coupled plasma atomic emission spectrometry

Introduction. Slag-forming mixtures play an important role in obtaining metal without non-metallic inclusions. Required properties of slag-forming mixtures (SFMs) directly depend on their chemical composition, that is why control of individual component content in a mixture is an important stage in the technological chain of metallurgical production. At the present time, it is a common practice to use inductively coupled plasma atomic emission spectrometry (ICP-AES for analyzing SFMs, requiring sample preparation by alloying with alkali fluxes, which makes it impossible to determine potassium and sodium oxides in a sample. That is why it is necessary to work out a procedure for simultaneous determination of calcium, silicon, magnesium, aluminium, potassium, and sodium oxides by the method of ICP-AES, which would include quantitative transferring of all components into a solution. For that purpose, it is suggested to use microwave digestion of samples in autoclaves.The purpose was to develop a procedure for simultaneous determination of specified components of SFMs using ICP-AES after transferring the sample into a solution in an autoclave under conditions of microwave heating, and to certify it reference materials of slag and fluxes.Materials and methods. Compositional analysis of slag-forming mixtures was conducted using an atomic emission spectrometer with inductively coupled plasma «iCAP 6500 Duo»; sample digestion was conducted with the use of the microwave system «ETHOS PLUS». The following brands of SFMs were chosen as research objects: Melubir 9563 and Accutherm ST-SP/235AL4D; AlsifluxGS-C7; SRCP015, SRCP173P. For calibrating the spectrometer and controlling correctness of determining the specified components, the following reference materials were used: reference materials of blast furnace slag, steelmaking slag, converter slag, and fused fluxes, which have close chemical composition.Research results. An ICP-AES analysis procedure has been developed for calibrating the spectrometer and controlling correctness of determining CaO, SiO2 , MgO, Al2 O3 , K2 O, Na2 O in reference materials of blast furnace slag, steelmaking slag, converter slag and fused fluxes, which allows to establish target components of SFMs quickly and reliably

Fixed and separate combination of solifenacin and tamsulosin in urinary disorders associated with benign prostatic hyperplasia: a choice based on price and value comparison

Objective. To determine the consequences of the use of a fi xed combination of solifenacin and tamsulosin in patients whom recommended the prescription of these drugs. Methods. Analysis of prices of drugs solifenacin + tamsulosin controlled release (Vasomni), solifenacin (Vesicare), tamsulosin controlled release (Omnic Okas) and tamsulosin modifi ed-release (several registered trade names of the drug) conducted on the basis of information from several sources: 1 — the register of maximum ex-works prices of manufacturers of vital and essential medicines, 2 — data on average prices in pharmacies of Moscow (as of 15.02.2018), 3 — weighted average prices of public procurement for 2018 according to the monitoring of the pharmaceutical market. To determine the points of relative value of drugs, a survey of experts was conducted: 1 — to determine the values of the criteria for the drugs under consideration — urologists; 2 — to determine the weight of the criteria — persons involved in the decision-making on the selection and purchase of drugs. Results. We found that the cost of the equivalent course dose of Vesomni was on 40-42 % lower than the combination of drugs Vesicar and Omnik Okas. Compared with the non-fi xed combination of solifenacin with tamsulosin in a drug form with modifi ed release, no signifi cant diff erences in price levels were found. At the same time, the relative value of a fi xed combination is 5-6 percentage points higher compared to non-fi xed combinations, mainly due to ease of use. Conclusion. Use of a fi xed combination of solifenacin + tamsulosin can lead to budget savings with an increase in the level of relative value

Influence of the material of weighing bottles on loss-on-drying reproducibility

One of the factors influencing the uncertainty of residual moisture measurements in biological medicinal products is the accumulation of electrostatic charge on the surfaces of weighing bottles and laboratory balances, which results in poor weighing reproducibility. The authors believe that the simplest and most economical solution to this problem is to use weighing bottles made of a conductive material, e.g. metal. The aim of the work was to evaluate the influence of the material of weighing bottles on the reproducibility of loss-on-drying (LOD) methods. Materials and methods: Model samples for the study were prepared from a sucrose-gelatin medium by lyophilisation and subsequent moisture sorption to achieve a certain residual moisture content. The authors assessed the samples’ mass uniformity using Shewhart’s X-charts, and analysed their residual moisture content using a loss-on-drying procedure with glass and metal weighing bottles. Statistical processing of the results was carried out by calculating the main statistical indicators: Student’s t-test and Fisher’s F-test. Results: Four batches of model samples were prepared and standardised in terms of average mass using Shewhart’s charts. The effect of weighing bottle materials was most pronounced at low residual moisture contents (less than 0.5%), with the relative standard deviation (RSD) values for the results obtained with glass and metal weighing bottles reaching 76% and 35%, respectively. For the samples with a higher residual moisture content (2–5%), the minimum RSDs with glass and metal weighing bottles were 15% and 6%, respectively. Conclusions: The study allowed for evaluating the influence of the material of weighing bottles on the results of LOD measurements and demonstrated a higher reproducibility with metal weighing bottles. This confirms the possibility of using metal weighing bottles in quality assessment of biological medicinal products for human use with LOD methods

Lyophilisation of bacterial test strains in a manifold-type apparatus: Effects of freezing and drying parameters, ampoule fill volume, and cotton filter density

Scientific relevance. Lyophilisation is the preferred method at the National Collection of Pathogenic Microorganisms (NCPM) of the Scientific Centre for Expert Evaluation of Medicinal Products of the Ministry of Health of the Russian Federation. Lyophilisation is used to provide for high standards of test-strain deposition, storage, and transportation and to ensure that test strains maintain their properties. Successful lyophilisation requires conducting experiments to establish the key parameters and critical conditions of the process.Aim. The study aimed to evaluate the effects that the speed and time of freezing, the time of drying, the fill volume of ampoules, and the density of cotton filters have on the quality of NCPM indicator microorganisms lyophilised in a manifold-type apparatus.Materials and methods. Pseudomonas aeruginosa NCTC 12924, Staphylococcus aureus NCTC 10788, and Salmonella Abony NCTC 6017 were freeze-dried using a manifold-type apparatus (M. S. R. 18, Usifroid). The authors used a low-temperature freezer at –70±2 °C for slow freezing and a mixture of dry ice and alcohol for quick freezing. The statistical analysis was performed using Microsoft Excel and Statistica 10.Results. The minimum time needed for freezing the samples in a low-temperature freezer at –70±2 °C was 4 hours. Further storage at this temperature for up to 1 month was shown possible without compromising the quality of the final product. The time needed for freezing the samples in a mixture of dry ice and alcohol was under 1 minute. No differences in quality parameters were observed between the lyophilised samples frozen slowly or quickly, except for the cake appearance. Quick freezing resulted in cakes that were non-uniform, crumbled, and pulled away from the ampoule walls, which is considered undesirable. The primary drying stage for ampoules with a fill volume of 0.2 mL took 6–8 hours. The secondary drying stage of 11, 18, 35, and 59 hours resulted in comparable lyophilisate quality: the authors observed no statistically significant differences in viable cell counts (CFU/mL) at the end of lyophilisation and at the end of stress testing. The residual moisture content after 59-hour secondary drying was less than 2%. The cotton filter density had a critical influence on the lyophilisate quality. Therefore, the authors recommend using cotton filters weighing 50 mg or less.Conclusions. The authors analysed the main stages of the lyophilisation process used for NCPM test strains and considered the effects that the speed and time of freezing, the time of drying, the fill volume of ampoules, and the density of cotton filters have on the quality of the final lyophilised product. The NCPM has implemented the results of this study in its work

КОМПЛЕКСНАЯ ОЦЕНКА ГЕНОФОНДА МОРКОВИ

The results of comprehensive assessment of the collection samples of carrot are presented. Such traits as a resistance to carrot psylla and carrot fly, high yield, earlyripeness, high content of carotene were evaluated. The carrot varieties total resistant to psylla were not found. The genotypes with combination of such traits as a mild tolerance to pests, stable productivity and fruits quality are recommended as the initial breeding material for development of new varieties and hybrids of carrot.Приведены результаты комплексной оценки коллекционных образцов моркови, включая устойчивость к морковной листоблошке и морковной мухе в сочетании с повышенными урожайностью, скороспелостью и содержанием каротина. Проведенные исследования показали, что среди изученных образцов моркови практически отсутствуют полностью устойчивые к морковной листоблошке. В этом плане представляют интерес для селекционного использования так называемые толерантные к вредителю сортообразцы, сохраняющие определенный уровень продуктивности, а также качества продукции. Выделенный в результате комплексной оценки исходный материал рекомендуется для использования в селекции как для выведения новых сортов, так и для создания гетерозисных гибридов

Anti-vortex state in cross-like nanomagnets

We report on results of computer micromodelling of anti-vortex states in asymmetrical cross-like ferromagnetic nanostructures and their practical realization. The arrays of cobalt crosses with 1 mkm branches, 100 nm widths of the branches and 40 nm thicknesses were fabricated using e-beam lithography and ion etching. Each branch of the cross was tapered at one end and bulbous at the other. The stable formation of anti-vortex magnetic states in these nanostructures during magnetization reversal was demonstrated experimentally using magnetic force microscopy.Comment: 19 pages, 9 figure

Grain quality indicators and size-dependent fractional composition in winter rye cultivars under the conditions of the Lower Volga region

Background. Grain quality indicators of winter rye cultivars were analyzed in connection with the size-dependent fractional composition of their grain in the Lower Volga environments.Materials and methods. The research material included 22 cultivars developed at various Russian scientific institutions, 3 Belarusian ones, and 3 cultivars bred at the Federal Center of Agriculture Research of the South-East Region. Comparative trials were conducted in 2021–2022 on 13.2 m2 plots in two field replications. The following grain quality indicators were studied: grain test weight, 1000 grain weight, size-dependent fractional composition, Hagberg falling number, amylogram peak height, starch gelatinization temperature, protein content, and rheological properties of the meal/water slurry.Results. Protein content was recorded at a level of 9.98–10.85%, while the starch gelatinization temperature was high due to the June air temperatures higher than the norm. Significant differences among the cultivars were found in the fractional composition of grain: 12 forms were identified with medium viscosity of the meal/water slurry and the fine-grain fraction content up to 30% of the total weight.Conclusions. There is a positive significant correlation between the five studied indicators characterizing the rheological properties of the meal/water slurry made from the grain of winter rye cultivars and the grain fraction composition (0.82*–0.91*)

Применение стандартных образцов доменных, сталеплавильных, конвертерных шлаков и сварочных плавленых флюсов при разработке методики анализа шлакообразующих смесей методом атомно-эмиссионной спектрометрии с индуктивно связанной плазмой

Introduction. Slag-forming mixtures play an important role in obtaining metal without non-metallic inclusions. Required properties of slag-forming mixtures (SFMs) directly depend on their chemical composition, that is why control of individual component content in a mixture is an important stage in the technological chain of metallurgical production. At the present time, it is a common practice to use inductively coupled plasma atomic emission spectrometry (ICP-AES for analyzing SFMs, requiring sample preparation by alloying with alkali fluxes, which makes it impossible to determine potassium and sodium oxides in a sample. That is why it is necessary to work out a procedure for simultaneous determination of calcium, silicon, magnesium, aluminium, potassium, and sodium oxides by the method of ICP-AES, which would include quantitative transferring of all components into a solution. For that purpose, it is suggested to use microwave digestion of samples in autoclaves.The purpose was to develop a procedure for simultaneous determination of specified components of SFMs using ICP-AES after transferring the sample into a solution in an autoclave under conditions of microwave heating, and to certify it reference materials of slag and fluxes.Materials and methods. Compositional analysis of slag-forming mixtures was conducted using an atomic emission spectrometer with inductively coupled plasma «iCAP 6500 Duo»; sample digestion was conducted with the use of the microwave system «ETHOS PLUS». The following brands of SFMs were chosen as research objects: Melubir 9563 and Accutherm ST-SP/235AL4D; AlsifluxGS-C7; SRCP015, SRCP173P. For calibrating the spectrometer and controlling correctness of determining the specified components, the following reference materials were used: reference materials of blast furnace slag, steelmaking slag, converter slag, and fused fluxes, which have close chemical composition.Research results. An ICP-AES analysis procedure has been developed for calibrating the spectrometer and controlling correctness of determining CaO, SiO2 , MgO, Al2 O3 , K2 O, Na2 O in reference materials of blast furnace slag, steelmaking slag, converter slag and fused fluxes, which allows to establish target components of SFMs quickly and reliably. Введение. Шлакообразующие смеси играют важную роль для получения «чистого» от неметаллических включений металла. Необходимые свойства шлакообразующих смесей (ШОС) напрямую зависят от химического состава, поэтому контроль содержания индивидуальных компонентов смесей является важным этапом в технологической цепи металлургического производства. В настоящее время для анализа шлакообразующей смеси практикуется метод атомно-эмиссионной спектрометрии с индуктивно связанной плазмой (АЭС ИСП), требующий пробоподготовки путем сплавления с щелочными плавнями, что делает невозможным определение оксидов калия и натрия в пробе. Поэтому существует необходимость разработки методики одновременного определения оксидов кальция, кремния, магния, алюминия, калия и натрия методом АЭС ИСП, включающей количественное переведение всех компонентов в раствор. Для этих целей предложено использовать микроволновое разложение проб в автоклавах.Цель работы. Разработка методики одновременного определения нормируемых компонентов ШОС методом АЭС ИСП после переведения пробы в раствор в автоклаве в условиях микроволнового нагрева, ее аттестация с применением стандартных образцов шлаков и флюсов.Материалы и методы. Определение компонентного состава ШОС осуществлялось с помощью атомно-эмиссионного спектрометра с индуктивно связанной плазмой «iCAP 6500 Duo»; разложение проб осуществлялось с помощью микроволновой системы «ETHOS PLUS». В качестве объектов исследования выбраны шлакообразующие смеси марок Melubir 9563 и Accutherm ST-SP/235AL4D; AlsifluxGS-C7; SRCP015, SRCP173P. Для градуировки спектрометра и контроля правильности определения нормируемых компонентов использованы СО шлаков доменных, сталеплавильных, конвертерных, а также флюсов сварочных плавленых, имеющих близкий химический состав.Результаты исследования. Разработана методика АЭС ИСП анализа, предназначенная для градуировки спектрометра и контроля правильности определения CaO, SiO2 , MgO, Al2 O3 , K2 O, Na2 O стандартных образцов шлаков доменных, сталеплавильных, конвертерных и флюсов сварочных плавленых, которая позволяет быстро и надежно определить целевые компоненты ШОС