A Method for Magma Viscosity Assessment by Lava Dome Morphology

Lava domes form when a highly viscous magma erupts on the surface. Several types of lava dome morphology can be distinguished depending on the flow rate and the rheology of magma: obelisks, lava lobes, and endogenic structures. The viscosity of magma nonlinearly depends on the volume fraction of crystals and temperature. Here we present an approach to magma viscosity estimation based on a comparison of observed and simulated morphological forms of lava domes. We consider a two-dimensional axisymmetric model of magma extrusion on the surface and lava dome evolution, and assume that the lava viscosity depends only on the volume fraction of crystals. The crystallization is associated with a growth of the liquidus temperature due to the volatile loss from the magma, and it is determined by the characteristic time of crystal content growth (CCGT) and the discharge rate. Lava domes are modeled using a finite-volume method implemented in Ansys Fluent software for various CCGTs and volcanic vent sizes. For a selected eruption duration a set of morphological shapes of domes (shapes of the interface between lava dome and air) is obtained. Lava dome shapes modeled this way are compared with the observed shape of the lava dome (synthesized in the study by a random modification of one of the calculated shapes). To estimate magma viscosity, the deviation between the observed dome shape and the simulated dome shapes is assessed by three functionals: the symmetric difference, the peak signal-to-noise ratio, and the structural similarity index measure. These functionals are often used in the computer vision and in image processing. Although each functional allows to determine the best fit between the modeled and observed shapes of lava dome, the functional based on the structural similarity index measure performs it better. The viscosity of the observed dome can be then approximated by the viscosity of the modeled dome, which shape fits best the shape of the observed dome. This approach can be extended to three-dimensional case studies to restore the conditions of natural lava dome growth

“Crust development inferred from numerical models of lava flow and its surface thermal measurements„

Propagation of a lava flow is governed by slope topography, magma rheology, heat exchange with the atmosphere and the underlying ter− rain, and the rate of the eruption. Highly viscous crust is formed due to cooling and solidification of the uppermost layer of the flow. We consider here two numerical model problems for lava flows, both based on the fundamental physics of a hot fluid flow: a model problem, where thermal conditions (e.g. temperature and heat flow) at the lava surface are unknown a priori (a direct model problem), and a model problem, where the lava surface conditions are known and determined from observations (an inverse model problem). In both models, the lava viscosity depends on temperature and the volume fraction of crystals. By way of solving the direct model problem, we perform a para− metric study of steady state lava flows to investigate the influence of the heat flux, viscosity, and effusion rate on the lava crust devel− opment. Numerical experiments show that a lava crust becomes thicker in the case of the nonlinear heat transfer compared to the case of a linear heat flow at the interface of lava with the atmosphere. Also, the crust thickens at lower lava effusion rates, while higher rates re− sult in a rapid lava advection, slower cooling, and development of a thinner crust. Moreover, a lava crust becomes thicker with a higher coefficient of conductive heat transfer, or a higher lava viscosity, or the growth of effective emissivity of the lava surface. By way of solv− ing the inverse model problem, we use an assimilation technique (that is, a method for an optimal combination of a numerical model of lava flows with observations) to propagate the temperature and heat flow, inferred from measurements at the interface between lava and the atmosphere, into the lava flow interior and to analyse the evolving lava crust. Results of thermal data assimilation illustrate that the physical parameters of lava flows, including the thickness of it crust, can be recovered from measured surface thermal data well enough at least for slow effusion rates. © 2019 the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved

A Method for Magma Viscosity Assessment by Lava Dome Morphology

Abstract: Lava domes form when a highly viscous magma erupts on the surface. Several types of lava dome morphology can be distinguished depending on the flow rate and the rheology of magma: obelisks, lava lobes, and endogenic structures. The viscosity of magma nonlinearly depends on the volume fraction of crystals and temperature. Here we present an approach to magma viscosity estimation based on a comparison of observed and simulated morphological forms of lava domes. We consider a two-dimensional axisymmetric model of magma extrusion on the surface and lava dome evolution, and assume that the lava viscosity depends only on the volume fraction of crystals. The crystallization is associated with a growth of the liquidus temperature due to the volatile loss from the magma, and it is determined by the characteristic time of crystal content growth (CCGT) and the discharge rate. Lava domes are modeled using a finite-volume method implemented in Ansys Fluent software for various CCGTs and volcanic vent sizes. For a selected eruption duration a set of morphological shapes of domes (shapes of the interface between lava dome and air) is obtained. Lava dome shapes modeled this way are compared with the observed shape of the lava dome (synthesized in the study by a random modification of one of the calculated shapes). To estimate magma viscosity, the deviation between the observed dome shape and the simulated dome shapes is assessed by three functionals: the symmetric difference, the peak signal-to-noise ratio, and the structural similarity index measure. These functionals are often used in the computer vision and in image processing. Although each functional allows to determine the best fit between the modeled and observed shapes of lava dome, the functional based on the structural similarity index measure performs it better. The viscosity of the observed dome can be then approximated by the viscosity of the modeled dome, which shape fits best the shape of the observed dome. This approach can be extended to three-dimensional case studies to restore the conditions of natural lava dome growth. © 2021, The Author(s).We are grateful to two anonymous reviewers for their constructive comments. Numerical experiments were carried out on the Uran computing cluster (Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, Yekaterinburg). The work was supported by the Russian Science Foundation (project no. 19-17-00027)

Lipidomic profile of seminal plasma in non-obstructive azoospermia with sperm maturation arrest

Introduction. The difference between obstructive and non-obstructive azoospermia with sperm maturation arrest is important for the choice of treatment tactics and adequate counseling of a married couple.Purpose of the study. The study aimed to assess the semen lipid profile in patients with sperm maturation arrest. Materials and methods. Samples of seminal plasma for lipid composition of 24 men with normozoospermia and 64 men with azoospermia were studied. Patients with azoospermia underwent microdissection testicular biopsy followed by the detection of testicular tissue pathology. Lipid extracts were analyzed by liquid chromatography with mass spectrometry. Lipid data were compared with the results of pathomorphological studies.Results. Comparison of two groups revealed a statistically significant concentration differences for 22 lipids detected in positive-ion mode and 11 lipids detected in negative-ion mode. Those lipids mainly belong to the classes hexosylceramides, sphingomyelins and phosphatidylcholines — simple ethers and oxidized lipids. In multivariate analysis, the following lipids were found to be statistically significant predictors of sperm maturation arrest: PC 16: 0_22: 6 lipid (β-coefficient: -0.73; 95% confidence interval (95% CI): -1.42 to -0.27; odds ratio (OR): 0.48; OR CI: 0.24 to 0.76; Wald's test: -2.58; p = 0.01), SM d20: 1/22:2 lipid (β-coefficient 4.96; 95% CI 2.29 to 9.13; OR: 142.31; OR CI: 9.90 to 9.22^103; Wald's test: 2.93; p = 0.003); PG 20:3_22: 6 lipid (β-coefficient 2.52; 95% CI 1.13 to 4.49; OR: 12.37; OR CI: 3.10 to 89.27; Wald's test: 3.02; p = 0.002); PC O- 16: 1/16:0 lipid (β-coefficient 1.96; 95% CI -4.12 to 0.27; OR: 0.14; OR CI: 0.02 to 0.76; Wald's test: -2.05; p = 0.04). The prediction model characteristics of sperm maturation arrest, obtained during cross-validation in the positiveion mode composed: sensitivity 91%, specificity 85%; in negative-ion mode: sensitivity 75%; specificity 81%.Conclusions. Even though early stages of spermatogenesis are equally preserved in both fertile men and men with homogeneous sperm maturation arrest, the semen in the studied group of patients differed in its lipid profile. Patients with non-obstructive azoospermia, associated with meiosis arrest, may have unique lipidomic characteristics of seminal plasma, which in the future will make it possible to differentiate various variants of severe male infertility using non-invasive methods

The course of fluorine intoxication

The purpose of the study is to study of the features of the modern clinic of chronic fluorine intoxication in workers.Цель исследования – изучение особенностей современной клиники хронической фтористой интоксикации у рабочих, подвергавшихся действию фтора

The role of educational films creating in the learning experiences

The students’ initiative in the educational films creation improves the assimilation of material on the "Disaster Medicine" stuff. Questioning of students after the creation of educational films has generated interest in scientific research in general and writing articles in particular.Творческая инициатива студентов при создании учебных фильмов способствует улучшению усвоения материала по предмету «Медицина катастроф». Анкетирование студентов после создания учебных фильмов породило интерес к научным исследованиям вообще и написанию статей в частности

Synthesis of γ-, δ-, and ε-Lactams by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)iminoesters

Highly enantiomerically enriched γ- and δ-lactams have been prepared by a simple and very efficient procedure that involves the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)iminoesters followed by desulfinylation of the nitrogen atom and spontaneous cyclization to the desired lactams during the basic workup procedure. Five- and six-membered ring lactams bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and ee’s up to >99%. A slight modification of the procedure also allowed the preparation of ε-lactams in good yields and very high enantioselectivities. Both enantiomers of the final lactams could be prepared with equal efficiency by changing the absolute configuration of the sulfinyl chiral auxiliary

СРАВНИТЕЛЬНЫЙ ПРОТЕОМНЫЙ АНАЛИЗ КОНДЕНСАТА ВЫДЫХАЕМОГО ВОЗДУХА У ПАЦИЕНТОВ С РАКОМ ЛЕГКОГО МЕТОДОМ МАСС-СПЕКТРОМЕТРИИ ВЫСОКОГО РАЗРЕШЕНИЯ

Analysis of exhaled breath condensate (EBC) is a promising non-invasive method to diagnose respiratory diseases. Most researchers emphasize the importance of proteomic analysis of EBC for early diagnosis of certain respiratory diseases including lung cancer. This study was aimed at identification of potential biomarkers of neoplastic disorders in EBC of patients with lung cancer using high-performance liquid chromatography and high resolution mass-spectrometry. The study involved 26 patients with lung carcinoma (21 males, 5 females, mean age 57 ± 12 years) and 23 healthy non-smokers (19 males, 4 females, mean age 30 ± 7 years). EBC samples were collected using a disposable portable condenser R-Tube. The most of proteins identified (65 %) belonged to keratin family including type 1 (1; 2; 5 and 6А) and type 2 (9; 10; 14; 16 and 17) cytoskeletal keratins and transport proteins (albumin, lipocalin-1). Keratin family proteins (5, 6 and 14) prevailed in lung cancer patients compared to controls (p < 0.05). Other 6 proteins were also detected predominantly in lung cancer patients including b-subunit and a-subunit of haemoglobin, nuclear ubiquitous casein (NUCKS), high-mobility group proteins (HMG-I/HMG-Y), and lactoferrin. Most of these proteins could be used as a diagnostic panel to detect lung cancer. Further investigations are needed to estimate diagnostic values of these biomarkers and their role in pathogenesis of lung cancer.Анализ конденсата выдыхаемого воздуха (КВВ) является перспективным неинвазивным методом оценки состояния дыхательной системы. Многие исследователи указывают на важность анализа протеома КВВ для раннего выявления заболеваний респираторного тракта, в т. ч. диагностики рака легкого (РЛ). В исследовании, в которое были включены 2 группы доноров: основная – больные РЛ (n = 26; 21 мужчина, 5 женщин; средний возраст – 56,5 ± 11,5 года) и контрольная (n = 23; 19 мужчин, 4 женщины; средний возраст – 30,0 ± 7,0 года) – здоровые некурящие добровольцы, у больных РЛ методом высокоэффективной жидкостной хроматографии и тандемной масс-спектрометрии была проведена идентификация потенциальных белков-онкомаркеров в КВВ. Образцы КВВ были собраны с помощью одноразового портативного конденсора R-Tube. Основную часть (65 %)  идентифицированных белков составили белки кератиновой группы, в т. ч. кератины цитоскелетные 1-го (1, 2, 5 и 6А) и 2-го (9, 10, 14, 16 и 17) типов, а также группа транспортных белков (альбумин, липокалин-1). Было показано, что группа кератинов (5, 6 и 14) более значительно выражена (р < 0,05) у онкологических больных по сравнению со здоровым контролем. Также 6 белков были преимущественно определены в КВВ доноров основной группы, в т. ч. b- и a-субъединицы гемоглобина, ядерный убиквитиновый казеин (NUCKS), белки группы высокой мобильности (HMG-I/HMG-Y), лактоферрин. Большинство выявленных белков может быть предложено в качестве панели для диагностики РЛ. Однако необходимы дальнейшие исследования для определения диагностической значимости предложенных биомаркеров и их роли в патогенезе РЛ

МЕДИКАМЕНТОЗНОЕ ЛЕЧЕНИЕ МУКОВИСЦИДОЗА В РОССИИ: АНАЛИЗ ДАННЫХ НАЦИОНАЛЬНОГО РЕГИСТРА (2014)

The aim of this study was to analyze drug therapy of patients with cystic fibrosis (CF) in Russia. Methods. Findings of the Russian National Register of CF patients, 2014, were used in this study. The 2014 Register included data for 2,131 patients (2,092 alive and 39 died) from 74 regions of Russia. The median age was 10.2 (15.2) years, 29.2% of patients were aged 18 years and older. We analyzed administration of bronchodilators, inhaled corticosteroids (ICS), systemic steroids, dornase alfa, hypertonic saline solution, macrolides, systemic and inhaled antibiotics, pancreatic enzymes, ursodeoxycholic acid, and fat-soluble vitamins. Results. Drug administration rates were as follows: bronchodilators, 65.9%; ICS, 21.7%; systemic steroids, 5.5%; macrolides, 32.4%; dornase-alfa, 92.8%; hypertonic saline solution, 45.9%; intravenous antibiotics, 62.3%; oral antibiotics, 73.3%; inhaled antibiotics, 41.3%; pancreatic enzymes, 93.3%; ursodeoxycholic acid, 91.4%; and fat-soluble vitamins, 88.3%. Conclusion. Compared to treatment of CF patients in the Western Europe, there is higher rate of administration of pancreatic enzymes, ursodeoxycholic acid, dornase alfa, hypertonic saline solution and intravenous antibiotics in Russia. Compared to treatment strategy in USA, there is higher rate of administration of pancreatic enzymes and lower rate of administration of bronchodilators, hypertonic saline solution and inhaled antibiotics in Russia. Муковисцидоз (МВ) – тяжелое мультисистемное заболевание, требующее комплексного медикаментозного и немедикаментозного лечения. Особенностям лекарственной терапии разнородных по числу и возрасту групп больных МВ, проживающих в разных регионах России, посвящено ограниченное число работ, однако общий анализ данных большой группы пациентов в рамках единого регистра ранее не проводился. Цель. Выявление особенностей медикаментозной терапии больных МВ в России по данным национального Регистра (2014). Материалы и методы. Использованы сведения о пациентах (n = 2 131; 2 092 живых и 39 умерших) из 74 регионов России, состоящих в национальном Регистре больных муковисцидозом (2014). Медиана возраста пациентов составила 10,2 (15,2) года, доля взрослых (не моложе 18 лет) – 29,2 %. Проанализирована частота назначения лекарственной терапии бронходилататорами, ингаляционными (иГКС) и системными (сГКС) глюкокортикостероидами (ГКС), дорназой альфа, гипертоническим раствором натрия хлорида, макролидами, системными и ингаляционными антибактериальными препаратами (АБП), панкреатическими ферментами, урсодезоксихолевой кислотой (УДХК), жирорастворимыми витаминами. Результаты. Частота применения медикаментозной терапии по России распределена следующим образом: бронходилататоры – 65,9 %; иГКС – 21,7 %; сГКС – 5,5 %; макролиды – 32,4 %; дорназа альфа – 92,8 %; гипертонический раствор натрия хлорида – 45,9 %; внутривенные АБП – 62,3 %; пероральные АБП – 73,3 %; ингаляционные АБП – 41,3 %; панкреатические ферменты – 93,3 %; УДХК – 91,4 %; жирорастворимые витамины – 88,3 %. Отмечено, что взрослым больным наиболее часто назначаются бронхолитические препараты, АБП и ГКС; реже применяются панкреатические ферменты и УДХК. Заключение. Среди особенностей терапии российских больных по сравнению со странами Западной Европы можно выделить высокую долю назначения панкреатических ферментов, УДХК, дорназы альфа, гипертонического раствора и внутривенных АБП. По сравнению с США чаще назначаются панкреатические ферменты, реже – бронходилататоры, гипертонический раствор натрия хлорида и ингаляционные АБП