Part I: Studies Towards Asymmetric α-halogenation and Mechanistic Studies of the Acrylate System with Organocatalyst and Part Ii: Synthesis of α-aryl Quaternary Carbon Centers

Organocatalytic transformations and asymmetric α-halogenation have become an important and dynamic research topic in organic chemistry in recent years. Despite the growing research in asymmetric halogenation of carbonyl compounds, such as aldehydes and ketones, there are no current examples in the literature of asymmetric halogenation of enolic systems even though many proposed reaction mechanisms go through enolate form. The research presented is the first example of enantioselective α-chlorination and α-bromination of α-hydroxyacrylate using organocatalysis and NMR studies towards achieving asymmetric induction of the enolic system. Despite the many publications that show when an organocatalyst binds to an aldehyde or ketone, the transition state goes through the enolate tautomer, that form is not stable otherwise and conforms back into starting material when the catalyst leaves the enolate. Whereas the α-hydroxyacrylate is stable in the enolic form by itself and does not need to be bound to any catalyst. Investigation into the mechanism of the reaction with the help of NMR studies showed that organocatalysts work as a base with the acrylate system and two major species are formed, E and Z isomers. This along with the fact that the catalyst is only loosely bound to the substrate is preventing desirable asymmetric induction from occurring. α-chlorination and α-bromination were successfully achieved with 100% yield and up to 30% ee

Ignition of the Soaring Droplet Sets of Waste-Derived Coal-Water Slurry With Petrochemicals

We have analyzed the ignition of droplet sets of waste-derived coal-water slurry with petrochemicals for the case of their soaring inside special combustion chamber. The fuel composition consists of filter cake of bituminous coal type G, waste turbine oil, water and plasticizer. Features of the ignition process were emphasized for groups of three soaring droplets in comparison with single droplet ignition. The ignition delay times were registered for particles that were deformed or segregated due to the interaction of initial fuel droplets with walls of the combustion chamber

Investigation of the Process of Methane-Oxygen Combustion in Steam Under the Atmospheric Pressure

In the article presented results of combustion methane-oxygen mixtures in the slightly superheated water steam under the atmospheric pressure. It is shown that exist dependence of flow rate combustible mixture and steam ratio (G[g.s]./G[s]) on the composition of the reacting mixture at the outlet of combustion chamber. There is a trend of increasing CO2 concentration in the reacting mixture at the outlet of combustion chamber with increase of G[g.s]./G[s]

INFLUENCE OF HOMEOSTATIC CYTOKINES – IL-7 AND IL-15 ON T-REGULATORY CELLS IN VITRO

Cytokines IL-7 and IL-15 are the most important humoral factors providing T-conventional cell pool reconstitution during homeostatic proliferation caused by lymphopenia. However, whether these cytokines can provide homeostatic maintenance and proliferation of T-regulatory (Treg) cells is largely unknown. Considering the association between homeostatic proliferation and the development of autoimmunity, we decided to investigate the ability of these factors to cause differentiation of Treg-cells into Th17-lymphocytes. Therefore, the purpose of this study was to investigate the influence of humoral factors of homeostatic proliferation (IL-7 and IL-15) on Treg-cells in vitro. The study used peripheral blood sampled from 22 healthy donors. PBMC fraction was isolated by Ficoll density gradient centrifugation. Proliferation was induced by IL-7, IL-15, and by a combination of IL-2 with anti-CD3-antibodies. The proliferation intensity of Tregs was evaluated by flow cytometry using CFSE in PBMC cultures by phenotype CD3+CD4+CD25+FoxP3+ and in the previously purified population of CD3+CD4+CD25+CD127lo-cells. In this case Treg-cells were obtained by immunomagnetic separation from PBMCs using a MACS Treg Isolation Kit. Also, the RORyt expression in CD3+CD4+CD25+FoxP3+-cells was evaluated during cultivation. Here, we have shown that IL-7 and IL-15 could support Treg-cells by number and phenotype. Also, we revealed that these factors provide FoxP3 expression in Treg-cells; meanwhile, stimulation with IL-2 + anti-CD3 can also cause induction of FoxP3 expression de novo in conventional CD4+ cells. Also, we have shown that IL-7 and IL-15 can cause lower-intensity proliferation of Treg-cells in comparison with IL-2 + anti-CD3. Herewith homeostatic cytokines didn’t have the ability to induce RORyt expression in both T-regulatory cells and CD4+ conventional T-lymphocytes. Thus, it has been shown that IL-7 and IL-15 can potentially participate in maintaining the total pool of Treg-cells during lymphopenia, when IL-2 deficiency occurs, without causing the induction of RORyt expression. However, how homeostatic cytokines affect the functional activity of Treg-cells remains unclear and requires further investigation

Pressure balance at the magnetopause: Experimental studies

The pressure balance at the magnetopause is formed by magnetic field and plasma in the magnetosheath, on one side, and inside the magnetosphere, on the other side. In the approach of dipole earth's magnetic field configuration and gas-dynamics solar wind flowing around the magnetosphere, the pressure balance predicts that the magnetopause distance R depends on solar wind dynamic pressure Pd as a power low R ~ Pd^alpha, where the exponent alpha=-1/6. In the real magnetosphere the magnetic filed is contributed by additional sources: Chapman-Ferraro current system, field-aligned currents, tail current, and storm-time ring current. Net contribution of those sources depends on particular magnetospheric region and varies with solar wind conditions and geomagnetic activity. As a result, the parameters of pressure balance, including power index alpha, depend on both the local position at the magnetopause and geomagnetic activity. In addition, the pressure balance can be affected by a non-linear transfer of the solar wind energy to the magnetosheath, especially for quasi-radial regime of the subsolar bow shock formation proper for the interplanetary magnetic field vector aligned with the solar wind plasma flow.Comment: 8 pages, 2 figure

Water uptake and transport properties of La1-xCaxScO3-α proton-conducting oxides

In this study, oxide materials La1-xCaxScO3-α (x = 0.03, 0.05 and 0.10) were synthesized by the citric-nitrate combustion method. Single-phase solid solutions were obtained in the case of calcium content x=0.03 and 0.05,whereas a calcium-enriched impurity phasewas found at x=0.10. Water uptake and release were studied by means of thermogravimetric analysis, thermodesorption spectroscopy and dilatometry. It was shown that lower calcium content in the main phase leads to a decrease in the water uptake. Conductivity wasmeasured by four-probe direct current (DC) and two-probe ascension current (AC)methods at different temperatures, pO2 and pH2O. The effects of phase composition,microstructure and defect structure on electrical conductivity, as well as correlation between conductivity and water uptake experiments, were discussed. The contribution of ionic conductivity of La1-xCaxScO3-α rises with decreasing temperature and increasing humidity. The domination of proton conductivity at temperatures below 500 °C under oxidizing and reducing atmospheres is exhibited. Water uptake and release as well as transport properties of La1-xCaxScO3-α are compared with the properties of similar proton electrolytes, La1-xSrxScO3-α, and the possible reasons for their differences were discussed. © 2019 by the authors.Russian Science Foundation, RSF: 16-13-00053Government Council on Grants, Russian FederationMinistry of Education and Science of the Republic of KazakhstanFunding: The research was partially supported by the Russian Science Foundation (Grant №16-13-00053) and the Ministry of Education and Science of the Republic of Kazakhstan (Project No. AP05130148). The education activity of Ph.D. and students involved into this work is supported by Act 211 of Government of the Russian Federation, agreement No. 02.A03.21.0006

Влияние гуморальных факторов гомеостатической пролиферации на T-регуляторные клетки in vitro

Aim. The aim of this study was the investigation of the influence of humoral factors of homeostatic proliferation IL-7 and IL-15 on T-regulatory cells in healthy donors.Materials and methods. The study included 15 conditionally healthy donors. Phenotyping and evaluation of expression changes of transcription factor FoxP3 and the main functional molecules on T-regulatory cells such as PD-L1, CTLA-4 and HLA-DR during cultivation under IL-7, IL-15 and anti-CD3 stimulation combined with IL-2 were performed by flow cytometry. Also, we estimated proliferation intensity of T-regulatory cells in the course of cultivation.Results. We revealed that humoral factors of homeostatic proliferation can effectively support a pool of T-regulatory cells during cultivation by number and phenotype and can maintain expression of important molecules such as PD-L1 and HLA-DR on regulatory T-cell surface. In addition, our study showed that IL-7 and IL-15 can cause relatively low T-regulatory cells proliferation in comparison to CD4+- lymphocytes.Conclusion. The observed ability of homeostatic proliferation factors to maintain T-regulatory cells pool presumably can play an important role in lymphopenic conditions when the number of effector cells is decreased and the insufficiency of interleukin IL-2 is observed, which plays a primary role in the homeostasis of T-regulatory cells in normal conditions.Цель – изучение влияния гуморальных факторов гомеостатической пролиферации интерлейкина (IL) 7 и IL-15 на фенотипические и функциональные характеристики T-регуляторных клеток у здоровых доноров in vitro.Материалы и методы. В исследование были включены 15 условно здоровых доноров. Методом проточной цитометрии проводились фенотипирование, оценка экспрессии FoxP3 и основных функциональных молекул T-регуляторных клеток (CTLA-4, PD-L1, HLA-D) до и после культивирования с IL-7 и IL-15, а также с анти-CD3-антителами в комбинации с IL-2. Оценивался пролиферативный ответ T-регуляторных клеток на стимуляцию указанными факторами.Результаты. Обнаружено, что факторы гомеостатической пролиферации способствуют сохранению фенотипа CD4+CD25+FoxP3+ и численному поддержанию T-регуляторных лимфоцитов в культуре, а также могут положительно влиять на экспрессию таких функциональных молекул, как PD-L1 и HLA-DR. Кроме того показано, что указанные факторы способны вызывать пролиферацию T-регуляторных клеток в существенно более низкой степени, чем CD4+-лимфоцитов.Заключение. Выявлена способность гомеостатических факторов IL-7 и IL-15 поддерживать фенотип T-регуляторных клеток и экспрессию функциональных маркеров. По-видимому, это играет важную роль в условиях лимфопении при снижении числа эффекторных лимфоцитов – основных продуцентов IL-2, которому отводится первостепенная роль в гомеостазе T-регуляторных клеток в норме

First record of Rhabdoceras suessi (Ammonoidea, Late Triassic) from the Transylvanian Triassic Series of the Eastern Carpathians (Romania) and a review of its biochronology, paleobiogeography and paleoecology

Abstract The occurrence of the heteromorphic ammonoid Rhabdoceras suessi Hauer, 1860, is recorded for the first time in the Upper Triassic limestone of the Timon-Ciungi olistolith in the Rarău Syncline, Eastern Carpathians. A single specimen of Rhabdoceras suessi co-occurs with Monotis (Monotis) salinaria that constrains its occurrence here to the Upper Norian (Sevatian 1). It is the only known heteromorphic ammonoid in the Upper Triassic of the Romanian Carpathians. Rhabdoceras suessi is a cosmopolitan species widely recorded in low and mid-paleolatitude faunas. It ranges from the Late Norian to the Rhaetian and is suitable for high-resolution worldwide correlations only when it co-occurs with shorter-ranging choristoceratids, monotid bivalves, or the hydrozoan Heterastridium. Formerly considered as the index fossil for the Upper Norian (Sevatian) Suessi Zone, by the latest 1970s this species lost its key biochronologic status among Late Triassic ammonoids, and it generated a controversy in the 1980s concerning the status of the Rhaetian stage. New stratigraphic data from North America and Europe in the subsequent decades resulted in a revised ammonoid biostratigraphy for the uppermost Triassic, the Rhaetian being reinstalled as the topmost stage in the current standard timescale of the Triassic. The geographic distribution of Rhabdoceras is compiled from published worldwide records, and its paleobiogeography and paleoecology are discussed

Oxygen isotope exchange in oxides La2−xCaxZr2O7−α

The oxygen isotope exchange method with equilibration of the isotope composition of the gas phase was used to obtain temperature dependences of oxygen diffusion coefficients and oxygen heterogeneous exchange rates with oxides La2−xCaxZr2O7−α (x = 0; 0.05; 0.1) in the temperature range of 600–900 °C and oxygen partial pressure equals 1 kPa. The oxygen diffusion coefficient was found to increase with increasing temperature and calcium content in the oxide. It is shown that an increase in the concentration of calcium leads to a decrease in the rate of dissociative adsorption through the segregation of the dopant on the surface and blocking of the active adsorption sites La-O, and also to an increase in the rate of incorporation due to an increase in the concentration of oxygen vacancies.В работе методом изотопного обмена кислорода с уравновешиванием изотопного состава газовой фазы исследована кинетика обмена кислорода газовой фазы с оксидами La2−xCaxZr2O7−α (x = 0; 0.05; 0.1), имеющих структуру пирохлора. Получены температурные зависимости коэффициентов диффузии и скоростей обмена кислорода с исследуемыми оксидами в температурном интервале 600–900 °C и давлении кислорода 1 кПа. Установлено, что с ростом температуры и с повышением содержания кальция в оксиде коэффициент диффузии кислорода увеличивается. Показано, что увеличение концентрации кальция приводит к уменьшению скорости диссоциативной адсорбции из-за сегрегации допанта на поверхности и, как следствие, блокирования активных центров адсорбции La-O, а также увеличению скорости инкорпорирования вследствие увеличения концентрации кислородных вакансий