Mechanism of mechanochemical synthesis of complex oxides and the peculiarities of their nano-structurization determining sintering

A mechanism of superfast mechanosynthesis reaction for oxide systems is proposed on the base of a dynamics study. The threshold effect and linear dependence of the chemical response on the effective temperature of the reaction zone are established. Major factors are determined: molecular mass of reagents, enthalpy and difference of reagents in Mohs’s hardness, which also influence the composition of the primary product. Primary acts are characterized by a superfast roller mechanism of mass transfer with the formation of a transient dynamic state (D)*. Secondary acts slowly approximate the composition of the product to the composition of the starting mixture by diffusion mass transfer in a deformation mixing regime with a contribution of a rotation (roller) mechanism. The list of structure types for complex oxides derived by mechanosynthesis includes perovskites, fluorites, pyrochlors, sheelites, and some other ones. Powders of crystal products display multilevel structurization. In all studied complex oxides strong disordering of the “anti-glass” type was observed. The mechanism of sintering was studied in BaTiO3 powders of different origin and in metastable complex oxides derived by mechanosynthesis. The major contribution in shrinkage belongs to rearrangements of crystalline particles as a whole. Structure transformations accompany, as a rule, sintering of inhomogeneous powders derived by mechanosynthesis

Modeling of process of gear milling for definition of the intense deformed state in replaceable many-sided plates of a worm mill

The tool equipment plays an important role in work of machine-building enterprises. One of the most important elements of equipment is the metal-cutting tool [1]. Replacement of the tool from HSS of steel on the cutting tool with use of WC-Co [2-7] sintered hard alloys gives increase in productivity and overall effectiveness of processing [8-11]. When the cutting ability of material of the tool increases, the universality of its application decreases therefore the most rational is comprehensive research approach which considers design of the tool the used WC-Co hard alloy. Design, production and testing of the toothed cutting tools, working off of the modes of cutting have to be carried out concerning a specific work piece and its material. When developing this kind of the tool it is necessary to consider features of WC-Co alloy as the cutting material, the cutting modes, destruction of the tool and other moments connected with its use. Influence of an initial contour on distribution of tension in the replaceable cutting many-sided plate. Results of calculation of the intense deformed state in a replaceable plate from the material WC-Co. Zones of stretching and compression are observed on the main cutting edge. Concentration of the dangerous stretching tension is located in a transitional zone between the direct side cutting edge to top as in this zone there is the greatest constraint of cutting. Respectively, the greatest destruction will happen in this zone. Important, the fact that in this part of the cutting edge there will be the biggest wear on a back surface. The analysis of isolines of distribution of tension showed that the stretching tension along a front surface of the replaceable cutting plate decreases because each replaceable cutting plate cuts off the part of material. First, work is entered by the made narrower cutting plate which cuts off metal an upper part of the cutting plate, and then the underestimated cutting plate which works with the side cutting edges works. As a result of the conducted researches it was established that with the progressive scheme of cutting in comparison with the standard scheme of cutting at which the initial profile of the making rail is made on DIN3972 at gear milling, dangerous tensile stresses in the cutting hard-alloy plates significantly decrease

Could inhalational drugs be interchangeable?

Clinical efficacy of an inhalational drugs depends on proper inhalation technique and aerodynamic properties of aerosol including the respirable fraction. Investigations of systemic pharmacokinetics of inhalational drugs could not always estimate their pharmacological equivalence so as rela tionships between the inhaled dose, the systemic concentration and the topic activity of an inhalational drug are not fully investigated. Therefore, identical formulation and similar route of administration are not sufficient to estimate pharmacological interchangeability. Possibility to interchange inhalational agents has still been controversial. As such, equal efficacy and safety of inhalational drugs with the same active substance could be esti mated in real clinical practice according to results of postmarketing trials and pharmacological surveillance. Spontaneous messages are a tool for gathering information about unwanted reactions or drug inefficacy and possible risks of substitution of drugs within the same international nonpro prietary name. In summary, it is necessary to estimate pharmacological equivalence and interchangeability of inhalational drugs carefully. This approach could improve efficacy and safety of treatment of patients with asthma and COPD. © 2017 Medical Education. All rights reserved

Implementation of a Group Cutting Scheme during Processing of Large-Module Gears with a Prefabricated Tool

Currently, when machining gears, the main problem arises - the resistance of a standard worm mill. In the current conditions of sanctions, import substitution and the launch of the State program for the development of its own metal cutting tool designs by tool companies, the creation of prefabricated structures can be considered a promising and effective solution, since this has been repeatedly confirmed by leading Russian researchers [1-8]

Could inhalational drugs be interchangeable?

Clinical efficacy of an inhalational drugs depends on proper inhalation technique and aerodynamic properties of aerosol including the respirable fraction. Investigations of systemic pharmacokinetics of inhalational drugs could not always estimate their pharmacological equivalence so as rela tionships between the inhaled dose, the systemic concentration and the topic activity of an inhalational drug are not fully investigated. Therefore, identical formulation and similar route of administration are not sufficient to estimate pharmacological interchangeability. Possibility to interchange inhalational agents has still been controversial. As such, equal efficacy and safety of inhalational drugs with the same active substance could be esti mated in real clinical practice according to results of postmarketing trials and pharmacological surveillance. Spontaneous messages are a tool for gathering information about unwanted reactions or drug inefficacy and possible risks of substitution of drugs within the same international nonpro prietary name. In summary, it is necessary to estimate pharmacological equivalence and interchangeability of inhalational drugs carefully. This approach could improve efficacy and safety of treatment of patients with asthma and COPD. © 2017 Medical Education. All rights reserved

Терапия бронхиальной астмы у детей: ингаляционные глюкокортикостероиды vs антагонисты лейкотриеновых рецепторов (обзор литературы)

Bronchial asthma is one of the most common chronic diseases of childhood and more often manifests in early childhood. Despite the fact that to date, available findings about efficacy and safety of bronchial asthma pharmacotherapy in children are limited, available data allow us to recommend a step-wise approach in patients aged 5 years and younger, including administration of inhaled glucocorticosteroids and leukotriene receptor antagonists. In this article, authors discuss the pharmacodynamics and pharmacokinetics properties of these classes of drugs onthe example of budesonide and montelukast, and compare the efficacy and safety of their use in pediatric practice.Бронхиальная астма является одним из наиболее часто встречающихся хронических заболеваний детского возраста и чаще манифестирует в раннем детстве. Несмотря на то что на сегодняшний день сведения об эффективности и безопасности фармакотерапии бронхиальной астмы у детей ограничены, имеющиеся данные позволяют рекомендовать у пациентов в возрасте 5 лет и младше поэтапный подход, подразумевающий в том числе назначение ингаляционных глюкокортикостероидов и антагонистов лейкотриеновых рецепторов. В данной статье авторами на примере будесонида и монтелукаста рассмотрены особенности фармакодинамики и фармакокинетики данных групп лекарственных средств, а также проведено сравнение эффективности и безопасности их применения в педиатрической практике

Терапия бронхиальной астмы у детей: ингаляционные глюкокортикостероиды vs антагонисты лейкотриеновых рецепторов (обзор литературы)

Bronchial asthma is one of the most common chronic diseases of childhood and more often manifests in early childhood. Despite the fact that to date, available findings about efficacy and safety of bronchial asthma pharmacotherapy in children are limited, available data allow us to recommend a step-wise approach in patients aged 5 years and younger, including administration of inhaled glucocorticosteroids and leukotriene receptor antagonists. In this article, authors discuss the pharmacodynamics and pharmacokinetics properties of these classes of drugs onthe example of budesonide and montelukast, and compare the efficacy and safety of their use in pediatric practice.Бронхиальная астма является одним из наиболее часто встречающихся хронических заболеваний детского возраста и чаще манифестирует в раннем детстве. Несмотря на то что на сегодняшний день сведения об эффективности и безопасности фармакотерапии бронхиальной астмы у детей ограничены, имеющиеся данные позволяют рекомендовать у пациентов в возрасте 5 лет и младше поэтапный подход, подразумевающий в том числе назначение ингаляционных глюкокортикостероидов и антагонистов лейкотриеновых рецепторов. В данной статье авторами на примере будесонида и монтелукаста рассмотрены особенности фармакодинамики и фармакокинетики данных групп лекарственных средств, а также проведено сравнение эффективности и безопасности их применения в педиатрической практике

Synthesis and sintering of ceramic nanocomposites with high mixed conductivity

Metastable solid solutions of complex oxides with fluorite and perovskite structures are obtained by mechanosynthesis. Dense ceramics on the base of these metastable phases was obtained by thermal sintering of nanopowders due to kinetic stabilization. Different degrees of a chemical interaction (interdiffusion) are observed during sintering of "perovskite+fluorite" and "perovskite+perovskite" composites. It is shown, that optimization of the composition, mixing conditions of individual phases and their sintering, preparation of ceramic composites with mixed conductivity for use in catalytic membrane reactors is possible. Unusual behavior of complex perovskites and fluorites is discovered during sintering, enabling determination of an optimum sintering temperature and time for which a qualitative explanation is given. It is established that rearrangement of fine crystalline particles as a whole plays a key role in shrinkage

Distribution and number of marine mammals in the open Barents Sea and their connection with capelin and polar cod distribution [presentation]

This paper presents the data on the character of distribution and the assessment of the number of marine mammals in the open part of the Barents Sea in autumn 2001-2004 by the results from PINRO’s aerial surveys using the airborne laboratory AN-26 “Arktika” and the annual joint Russian-Norwegian vessel ecosystem survey for pelagic fish including capelin and polar cod. The aerial surveys were carried out being combined with the vessel surveys and their tacks coincided or crossed in several points

Pharmacokinetics, safety, and tolerance of anagrelide, the first domestic generic, compared with reference drug [Фармакокинетика, безопасность и переносимость первого отечественного дженерика анагрелида в сравнении с референтным препаратом]

Background. Anagrelide is used for the treatment of essential thrombocythemia. This drug selectively affects thrombocytes without inducing pronounced myelosuppression, which provides a satisfactory safety profile. Aim. To compare pharmacokinetics and to assess bioequivalence of two anagrelide drugs for oral administration in healthy volunteers. Materials & Methods. Open, randomized, two-period, two-sequence, crossover study comparing pharmacokinetics and bioequivalence of anagrelide included 30 volunteers. The participants received a single dose of either test or reference drug, depending on the study period. Serial blood samples for pharmacokinetic analysis were collected within 12 hours after drug administration. Plasma anagrelide concentration was measured by high-performance liquid chromatography/mass spectrometry. Pharmacokinetic parameters were analyzed by non-compartmental method. ANOVA analysis of variance was used for assessing the difference between the mean values of the AUC0-t, AUC0-∞ and Cmax pharmacokinetic parameters at 5 % significance level. Results. The mean values of maximum concentration (Сmax) after a single dose of anagrelide were 12.68 ± 2.99 ng/mL and 12.46 ± 3.15 ng/mL for test and reference drugs, respectively. Relative bioavailability was 1.16 ± 0.18. The AUC0-12 mean values calculated by anagrelide concentrations after a single dose of test and reference drugs were 30.38 ± 7.0 ng • h/mL and 28.78 ± 7.50 ng • h/mL, respectively, and the AUC0-∞ mean values were 31.13 ± 7.15 ng • h/mL and 29.55 ± 7.61 ng • h/mL, respectively. The assessment of main vital functions and laboratory parameters did not reveal any effect of the drugs on the health status of trial participants. Conclusion. Pharmacokinetic profile of the test drug (generic anagrelide) did not considerably differ from that of reference drug, which indicates in vivo bioequivalence of it. The assessment of drug safety yielded satisfactory tolerance; no serious adverse events have been reported. © 2020 Practical Medicine Publishing House. All rights reserved