Диагностические возможности компьютерной томографии при патологиях брюшной полости у мелких домашних животных

Computed tomography (CT) provides highly informative results as a diagnostic test used to diagnose diseases of the abdominal cavity. Correct animal's positioning and a scan examination protocol allow to obtain a number of high-quality CT images. An artificial contrast agent given by either enteral or parenteral route helps visualize more clearly local changes in the structure of tissues of the abdominal cavity on the CT image. CT can detect tiny tumor foci located within the parenchyma of abdominal organs of the animal body. CT is usually ordered for a full examination of the abdominal cavity to clarify a diagnostic in conjunction with ultrasound and radiography modalities.Применение метода компьютерной томографии (КТ) дает высокоинформативные результаты при диагностике заболеваний брюшной полости. Использование адекватных укладок животного и протокола исследования позволяет получать качественное изображение на КТ-снимках. Искусственное контрастирование препаратами с энтеральным и парентеральным способами введения помогает более четко визуализировать на КТ локальные изменения в структуре тканей органов брюшной полости. КТ может обнаружить мельчайшие опухолевые очаги, расположенные внутри паренхимы органов брюшной полости у животных. Метод КТ чаще всего назначается для полного обследования органов брюшной полости, а также для уточнения диагноза, поставленного с помощью УЗИ и рентгенографии

High-temperature electrochemistry of calcium

Electrolytically produced calcium is one of the most demanded materials in obtaining pure materials. At the same time, the existing technologies and devices for the electrolytic production of calcium were developed in the last century, and at present there are practically no works aimed at optimizing them. However, increasing the capacity and efficiency of existing devices for the production of calcium is in demand. To analyze possible ways to improve calcium production, a comprehensive understanding of the processes occurring at the electrodes and in the electrolyte during electrolytic production of calcium is required.This review briefly outlines the main points concerning the electrolytic production of calcium: from a brief history of the development of methods for the electrolytic production of calcium and established ideas about its physicochemical processes to information about new developments using the electrolysis of CaCl2-based melts. Review content: brief history of process development; base electrolyte for calcium production, including preparation of CaCl2 and influence of additions on it physicochemical properties; data on calcium solubility in CaCl2; information about alternative electrolytes for calcium production; short description of electrode processes in the CaCl2-based melts; proposed technologies and devices for the electrolytic production of calcium. keywords: calcium, calcium chloride, ion-electron liquid, Cu–Ca alloy, molten salt, calcium solubility, electrode processes, inert anode, electrolysis, current efficiency, electrolyzer DOI: https://doi.org/10.15826/elmattech.2022.1.00

High-Temperature Electrochemistry of Calcium

Received: 12 July 2022. Accepted: 03 September 2022.Electrolytically produced calcium is one of the most demanded materials in obtaining pure materials. At the same time, the existing technologies and devices for the electrolytic production of calcium were developed in the last century, and at present there are practically no works aimed at optimizing them. However, increasing the capacity and efficiency of existing devices for the production of calcium is in demand. To analyze possible ways to improve calcium production, a comprehensive understanding of the processes occurring at the electrodes and in the electrolyte during electrolytic production of calcium is required. This review briefly outlines the main points concerning the electrolytic production of calcium: from a brief history of the development of methods for the electrolytic production of calcium and established ideas about its physicochemical processes to information about new developments using the electrolysis of CaCl2-based melts. Review content: brief history of process development; base electrolyte for calcium production, including preparation of CaCl2 and influence of additions on it physicochemical properties; data on calcium solubility in CaCl2; information about alternative electrolytes for calcium production; short description of electrode processes in the CaCl2-based melts; proposed technologies and devices for the electrolytic production of calcium

Synthesis and Antihypoxic Activity of 2-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic Acids and Their Reaction Products with Substituted Hydrazines

Introduction. Hypoxia is a violation of oxidative processes in tissues that occur when oxygen is insufficiently supplied to them or when its utilization is disrupted during biological oxidation. Chronic hypoxic damage plays an important role in the occurrence and development of various diseases, which necessitates the synthesis of new compounds with antihypoxic activity.Aim. The purpose of this study is to synthesize and investigate the antihypoxic activity of 2-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic acids and their reaction products with substituted hydrazines.Materials and methods. 2-Aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic acids (I–VI) were obtained with high yields as a result of the interaction of 4-aroyl-2,4-dioxobutane acids with 3-amino-5,5-dimethylcyclohex-2-enone. Interaction of 2-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic acids with benzyl- and (2-phenylethyl)hydrazines 5-aryl-2-benzyl- and 2-(2-phenylethyl)-8,8-dimethyl-3,7,8,9-tetrahydro-2H-pyrido[4,3,2-de]cinnoline-3-ones (VII–XII) were obtained. As a result, 12 compounds were synthesized. The study of the antihypoxic activity of the obtained compounds was carried out in vivo on a model of normobaric hypoxia with hypercapnia.Results and discussion. The synthesized compounds were tested for the presence of antihypoxic action. The most pronounced antihypoxic activity is characteristic of compounds VI and VIII, which have a methoxy group and a methyl radical in the para-position of the phenyl substituent at C5, respectively. The presence of chlorine in the structure of compound III, fluorine in compound X and the absence of substituents (compounds I and VII) contribute to the prohypoxic effect. According to the results of the study, both quinolincarboxylic acids and pyridocinnolines are potential antihypoxants.Conclusion. A comparative analysis of the antihypoxic activity of the synthesized compounds was carried out, the relationship between their structure and severity of action was established, the most active substances were identified

ANALYSIS OF THE POSSIBILITIES OF USING THE SIMULATED CHARACTERISTICS OF A TRANSISTOR IN THE DEVELOPMENT OF AN AMPLIFIER

Описан метод сравнения модели транзистора с его справочными характеристиками для выявления несоответствия параметров с реальным. Исследованы выходные вольтамперные характеристики отечественного высокочастотного маломощного транзистора КТ368А, проведена его проверка в схеме разработанного усилителя, проведены измерения и сравнение АЧХ. Показано, что характеристики модели транзистора не соответствуют справочным, изза чего АЧХ имеют отличия. В частности, значения тока коллектора и сопротивления базы отличаются в 23 раза по сравнению с расчетами, проведенными по техническим параметрам. Коэффициент усиления по напряжению и полоса пропускания отличаются от собранного усилителя в 3 и 1.2 раза соответственно.A method is described for comparing the transistor model with its reference characteristics to identify the discrepancy between the parameters and the real one. The output voltampere characteristics of the domestic highfrequency lowpower transistor KT368A were investigated, its verification was carried out in the circuit of the developed amplifier, measurements and comparison of frequency response were carried out. It is shown that the characteristics of the transistor model do not correspond to the reference ones, which is why the frequency response has differences. In particular, the values of the collector current and the base resistance differ by 23 times compared to calculations carried out according to technical parameters. The voltage gain and bandwidth differ from the assembled amplifier by 3 and 1.2 times, respectively

REVIEW AND STUDY OF MATERIALS WITH A HIGH VALUE OF THE IMAGINARY PART OF THE DIELECTRIC CONSTANT

Приведена классификация материалов, предназначенных для обеспечения требований ЭМС, по различным параметрам. Экспериментально исследованы электродинамические параметры нескольких образцов пирамидальных по форме материалов из жесткого формованного пенополиуретана в защитной оболочке из микрогофрокартона и из мягкого искусственного материала. Показано, что электродинамические параметры некоторых образцов материалов меняются нелинейно во всем частотном диапазоне. В частности, образцы материала из жесткого формованного пенополиуретана имеют нелинейные зависимости по всем измеряемым параметрам.The classification of materials for EMC testing according to various parameters is given. The electrodynamic parameters of several samples of pyramidal materials made of hard molded polyurethane foam in a protective shell made of microfoam and soft artificial material were experimentally studied. It is shown that the electrodynamic parameters of some samples of materials vary nonlinearly over the entire frequency range. In particular, samples of rigid molded polyurethane foam material have nonlinear dependencies on all measured parameters

СКОРОСТЬ РАСТВОРЕНИЯ ОКСИДА СВИНЦА (II) В ЭКВИМОЛЬНОМ РАСПЛАВЕ KCl–PbCl2

Lead (II) oxide dissolution rates in equimolar KCl–PbCl2 melt at Т = 773, 823 & 873 K have been determined by gravimetrical method. In temperature rising from 773 to 873 K, the initial dissolution rate is shown to increase from 23,9 to 45,6 mg/(cm2·min) at the conditional factor of roughness equal to 10. Then the rate values for all temperatures are lined up and after 25 min they are close to zero, thus meaning the diffusion mode of the process at the natural convection conditions. The activation energy of PbO interaction with KCl–PbCl2 melt is 37,370±0,118 kJ/mol. The PbO limiting concentration in equimolar KCl–PbCl2 melt at temperatures 773, 823 and 873 K is 9,1; 10,6; 13,5 wt.% respectively. С помощью гравиметрического метода экспериментально определены скорости растворения (W) оксида свинца (II) в эквимолярном расплаве KCl–PbCl2 при Т = 773, 823 и 873 К. Показано, что с повышением температуры с 773 до 873 К на- чальная величина W возрастает с 23,9 до 45,6 мг/(см2·мин) при условном коэффициенте шероховатости, равном 10. Далее значения W для всех температур выравниваются и после 25 мин близки к нулю, что говорит о диффузионном режиме про- цесса в условиях естественной конвекции. Энергия активации процесса взаимодействия PbO c расплавом KCl–PbCl2 составила 37,370±0,118 кДж/моль. Определена предельная концентрация PbO в эквимолярном расплаве KCl–PbCl2, ко- торая при Т = 773, 823 и 873 К соответственно равна 9,1, 10,6 и 13,5 мас.%

О МЕХАНИЗМЕ ВОССТАНОВЛЕНИЯ ОКСИДОВ В РАСПЛАВАХ ХЛОРИДА КАЛЬЦИЯ

Alternative notions on the reduction mechanism of crystalline metal oxides during the electrolysis of CaCl2 melts, which is actively discussed worldwide is scientific publications for recent 15 years, are described. It is shown based on the known experimental data on the nature of the Ca–CaCl2 solution and its reduction properties that metal oxides can reduce without the direct contact with the cathode in the volume of a homogeneous Ca–CaCl2 salt near cathode, i.e., catholyte. The reducing agent is calcium dissolved in a form of Ca+ cations in this case. In this case, the reaction surface area multiply increases, which favorably affects the course of heterophase chemical reactions. The method of introduction of Ca+ ions into the salt melt can be both by electrolysis of CaCl2 or due to the dissolution of metal calcium in this case, and it does not vary the essence of our process model.Изложены альтернативные представления о механизме восстановления кристаллических оксидов металлов при электролизе расплавов CaCl2, активно обсуждаемом в мировой научной литературе последние 15 лет. На основании известных экспериментальных данных о природе раствора Ca–CaCl2 и его восстановительных свойствах показано, что восстановление оксидов металлов может происходить без прямого контакта с катодом в объеме гомогенного солевого расплава Ca–CaCl2 вблизи катода, т.е. в католите. Восстановителем в этом случае является растворенный в расплаве кальций в форме катионов Са+. При этом многократно увеличивается площадь реакционной поверхности, что благоприятно сказывается на протекании гетерофазных химических реакций. Способ введения ионов Са+ в солевой расплав может быть любым: путем электролиза CaCl2 или за счет растворения в данном расплаве металлического кальция, и он не изменяет сути предлагаемой модели процесса

Organic chemistry. History and mutual relations of universities of Russia

© 2017, Pleiades Publishing, Ltd. The review describes the history of development of organic chemistry in higher schools of Russia over a period of 170 years, since the emergence of organic chemistry in our country till now