The boundary integral theory for slow and rapid curved solid/liquid interfaces propagating into binary systems

The boundary integral method for propagating solid/liquid interfaces is detailed with allowance for the thermo-solutal Stefan-type models. Two types of mass transfer mechanisms corresponding to the local equilibrium (parabolic-type equation) and local non-equilibrium (hyperbolic-type equation) solidification conditions are considered. A unified integro-differential equation for the curved interface is derived. This equation contains the steady-state conditions of solidification as a special case. The boundary integral analysis demonstrates how to derive the quasi-stationary Ivantsov and Horvay–Cahn solutions that, respectively, define the paraboloidal and elliptical crystal shapes. In the limit of highest Péclet numbers, these quasi-stationary solutions describe the shape of the area around the dendritic tip in the form of a smooth sphere in the isotropic case and a deformed sphere along the directions of anisotropy strength in the anisotropic case. A thermo-solutal selection criterion of the quasi-stationary growth mode of dendrites which includes arbitrary Péclet numbers is obtained. To demonstrate the selection of patterns, computational modelling of the quasi-stationary growth of crystals in a binary mixture is carried out. © 2018 The Author(s) Published by the Royal Society. All rights reserved.Russian Science Foundation, RSF: 16-11-1009550WM1541Data accessibility. This article has no additional data. Authors’ contributions. All authors contributed equally to the present review paper. Competing interests. The authors declare that they have no competing interests. Funding. This work was supported by the Russian Science Foundation (grant no. 16-11-10095) and the German Space Center Space Management under contract no. 50WM1541

Diagnostic finding of fever of unknown origin.

Fever of an unclear origin is an interdisciplinary problem, since clinical practice shows that diagnosing requires a collaborative approach of specialists of various profiles. The article highlights the results of a retrospective analysis of 35 medical reports of patients hospitalized to Tyumen Regional Clinical Hospital from 2016 to 2018. Three groups of patients were identified: a fever of unknown origin induced by an infectious pathology; a fever of unknown origin induced by somatic pathology; fevers with cause undeciphered despite a thorough examination and informative methods. The authors have conducted an analysis of complaints, clinical examination, and laboratory data in the selected groups. The paper reflects the economic costs of the diagnostic research on the patients diagnosed with the fever of an unclear origin.Лихорадка неясного генеза, является междисциплинарной проблемой, поскольку клиническая практика показывает, что для постановки диагноза требуется совместный подход специалистов разного профиля. В статье освещены результаты ретроспективного анализа 35 историй болезни пациентов госпитализированных в ГБУЗ ТО Областную инфекционную клиническую больницу г. Тюмени в период за 2016-2018 гг. Выделено 3 группы пациентов с диагнозом: лихорадка неясного генеза, вероятно индуцированная инфекционной патологией; лихорадка неясного генеза, вероятно индуцированная соматической патологией; лихорадки причину которых расшифровать не удается, несмотря на тщательное обследование с использованием информативных методов. Проведен анализ жалоб, клинического осмотра и лабораторных данных в выделенных группах. В работе отражены экономические затраты на диагностический поиск пациентов с диагнозом лихорадка неясного генеза

On the unsteadiness time of primary dendritic growth

The evolution of the growth rate of a dendritic tip for nonisothermal crystal growth from the moment of crystal formation to the moment when the growth rate attains its steady-state value is considered. Gibbs-Thomson condition for highly nonequilibrium rapidly moving crystallization of a pure one-component liquid is used to determine the time dependence of the growth rate of a dendritic tip. It is shown that the dependence of the growth rate on overcooling has the form of an exponential law. Under the condition of constant overcooling an estimation of the time of reaching the steady-state regime of growth is obtained. The analytically derived velocity of growth as a function of time coincides with numerical calculations

Structural and Functional Organization of the Vestibular Apparatus in Rats Subjected to Weightlessness for 19.5 Days Aboard the Kosmos-782 Satellite

The vestibular apparatus was investigated in rats subjected to weightlessness for 19.5 days. The vestibular apparatus was removed and its sections were fixed in a glutaraldehyde solution for investigation by light and electron microscopes. Structural and functional charges were noted in the otolith portions of the ear, with the otolith particles clinging to the utricular receptor surface and with the peripheral arrangement of the nucleolus in the nuclei of the receptor cells. It is possible that increased edema of the vestibular tissue resulted in the destruction of some receptor cells and in changes in the form and structure of the otolith. In the horizontal crista, the capula was separated

Изучение закономерностей осаждения тонких сорбционно-активных пленок диоксида марганца на различных полимерных носителях

Manganese dioxide (MnO2) is used as a sorption material for the isolation of a wide range of substances from aqueous media. A number of composite materials containing MnO2 are known, while in the scientific literature there are no systematic data on the possibilities of obtaining flat thin-layer sorbents of manganese dioxide on other polymer carriers. In this study, a number of flat thin-layer sorbents, consisting of manganese dioxide deposited on the surface of various carriers, were synthesized. The most common flat materials were used as carriers - polyethylene (PE), polypropylene (PP), biaxially oriented polypropylene film (BOPF), polyethylene terephthalate (PET), cellulose triacetate (CTA). The films were kept in an acidic solution of potassium permanganate, washed, and the manganese content was determined. It was shown that according to the rate of deposition of manganese dioxide on the surface of the carrier, these materials are arranged in a row: CTA >> PE> BOPF> PET ≈ PP. It was found that the dependences of the specific content of manganese dioxide on the surface of polymer carriers were well approximated by straight lines (R2 = 0.964 - 0.997); the results of linear processing of the dependences were used to determine the deposition rates of manganese dioxide, ranging from 1.55 ± 0.26 μg/(cm2 day) for PP up to 166 ± 11 μg/(cm2 day) for CTA. It was shown that the high rate of deposition of manganese dioxide on the surface of the CTA in comparison with other polymer carriers was most likely due to the macroporous texture of the CTA surface. It was also shown that with a specific content of manganese dioxide of the order of 150-300 μg/cm2 achieved after 1-2 days of CTA treatment in a permanganate solution, a continuous uniform sorption-active layer was formed, and with a longer exposure time, an increase in the average layer thickness occurred due to the growth of individual crystallites already on the surface of a continuous layer of manganese dioxide, leading to a significant heterogeneity of the sorption-active surface, as well as to a stable deformation of the film. The sorption of 223Ra was studied on a series of obtained sorbents. It was shown that the amount of manganese dioxide phase in the composition of thin-layer sorbents had practically no effect on the sorption of radium from a salt-free solution, but strongly influenced sorption from 0.5 M NaCl. Also, for the MnO2-CTA sorbent the deterioration of the quality of the alpha spectrum due to the diffusion of radium deep into the sorbent was demonstrated. © 2021 Semenishchev V.S., Oglezneva V.Yu., Titova S.M.,Malyshev A.S., Filinkova V.K.Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 20-03-00931

Pharmacoepidemiological study of the safety of drug use in children by analyzing the Russian database of spontaneous reports

Purpose. To study the structure of serious adverse drug reactions and «off label» drug use in children by means of analysis of the national pharmacovigilance database. Materials and methods. We analyzed 341 spontaneous reports about serious adverse reactions in children, submitted to the Russian pharmacovigilance database in 2012, and 467 suchlike spontaneous reports registered in 2015. Results. Children of preschool age have higher risk of medical therapy complications. Most frequently, skin (33,4% in 2012 and 38,7% in 2015) and organism as a whole (21,4 and 21,1%, respectively) were involved in the pathological process. Antimicrobial drugs for systemic use (43,5% in 2012 and 43,8% in 2015) and drugs for nervous system (25,1 and 26,1% respectively) often caused them. Unexpected serious adverse reactions accounted for 16,9% of all complications in children in 2012, 10,8% in 2015. It was established that 58,7% of suspected medicines in 2012 and 47,5% in 2015, the use of which was associated with the development of serious complications in pharmacotherapy in children, were prescribed with deviations from the recommendations of approved prescribing drug information. The main types of «off-label» drug use were inappropriate indications, deviations from the recommended dosage regimen, the use of a drug in the age group of patients, wherein the drug has not been approved, and the use of a drug in the presence of contraindications to its use. Conclusion. Our research confirms that the practice of «off-label» drug use in children is an independent risk factor for developing adverse drug reactions. It is shown that the method of spontaneous reporting can help to identify the problems of drug safety and to develop recommendations for minimizing the risk of complications of pharmacotherapy in pediatric practice

The Russian study of «off-label» drug use in pediatric practice: 2015 vs 2012

Purpose. To study and compare the structure of off-label drug use in children in 2012 and 2015 by means of analysis of the national pharmacovigilance database. Materials and methods. We conducted a comparative analysis of 341 spontaneous reports about serious adverse reactions in children, submitted to the Russian pharmacovigilance database in 2012, and 467 suchlike spontaneous reports registered in 2015. Approved in the Russian Federation prescribing drug information was used to identify «off label» drug use. Results. It was established that 58,7% of suspected medicines in 2012 and 47,5% in 2015, the use of which was associated with the development of serious complications in pharmacotherapy in children, were prescribed with deviations from the recommendations of approved prescribing drug information. Systemic antimicrobial agents and drugs for the treatment of nervous system diseases were the most common groups of drugs prescribed off-label in pediatric practice. The main types of off-label violations were inappropriate indications, deviations from the recommended dosage regimen and the use of a drug in the age group of patients, wherein the drug has not been approved. Conclusion. Our research confirms, that the practice of off-label drug use in children is not safe. It is shown that spontaneous reporting is an effective method of study the problems of drug safety in children