108 research outputs found

    Bulk-boundary correspondence in three dimensional topological insulators

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    We discuss the relation between bulk topological invariants and the spectrum of surface states in three dimensional non-interacting topological insulators. By studying particular models, and considering general boundary conditions for the electron wavefunction on the crystal surface, we demonstrate that using experimental techniques that probe surface states, only strong topological and trivial insulating phases can be distinguished; the latter state being equivalent to a weak topological insulator. In a strong topological insulator, only the {\it parity} of the number of surface states, but not the number itself, is robust against time-reversal invariant boundary perturbations. Our results suggest a \z definition of the bulk-boundary correspondence, compatible with the \z classification of topological insulators.Comment: TeXLive (Unix), revtex4-1, 7 pages, 3 figure

    Tunable unconventional Kondo effect on topological insulator surfaces

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    We study Kondo physics of a spin-12 impurity in electronic matter with strong spin-orbit interaction, which can be realized by depositing magnetic adatoms on the surface of a three-dimensional topological insulator. We show that magnetic properties of topological surface states and the very existence of Kondo screening strongly depend on details of the bulk material, and specifics of surface preparation encoded in time-reversal preserving boundary conditions for electronic wavefunctions. When this tunable Kondo effect occurs, the impurity spin is screened by purely orbital motion of surface electrons. This mechanism gives rise to a transverse magnetic response of the surface metal, and to spin textures that can be used to experimentally probe signatures of a Kondo resonance. Our predictions are particularly relevant for STM measurements in PbTe-class crystalline topological insulators, but we also discuss implications for other classes of topological materials

    Microstructure and mechanical properties of V-4Ti-4Cr alloy as a function of the chemical heat treatment regimes

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    The regularities of the formation of a heterophase structure and mechanical properties of V–4Ti–4Cr alloy as a function of thermomechanical and chemical heat treatments are studied. The regimes of thermomechanical treatment which provide the formation of a heterophase structure with a homogeneous volume distribution of oxycarbonitride nanoparticles with a size of about 10 nm and an increase in the volume content and thermal stability of this phase and which provide an increase in the temperature of alloy recrystallization are developed. The formation of the heterophase structure results in a substantial (up to 70%) increase in the short-term high-temperature strength of the alloy at T = 800°C. The increase in the strength is achieved while keeping a rather high level of plasticity

    Characteristics of marine strain Streptomyces sp. with antimicrobial and cytotoxic activity

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    The Black Sea is a unique water basin consisting of a thin superficial oxygenic layer with moderate salinity, and a deep anoxic water mass. The microbiota of the Black Sea remains relatively understudied, which makes it interesting first of all from the most practical point of view of the search for producers of new biologically active compounds. A strain of actinobacteria Streptomyces sp. ONU 561 was isolated from the surface of mussel shells collected in the coastal zone of Odesa. It demonstrated a wide range of antagonistic activity, inhibiting the growth of a set of opportunistic pathogens, including representatives of Staphylococcus aureus, Escherichia coli, Proteus vulgaris, and Klebsiella pneumoniae. In addition, bacteria of this strain were able to inhibit the growth of all tested strains of mycelial fungi, including representatives of Aspergillus niger, A. flavus and Fusarium oxysporum species, and Candida albicans yeast. A significant cytotoxic effect was revealed in the cell cultures of human malignant cells – human rhabdomyosarcoma (RD) and human laryngeal adenocarcinoma (Hep-2). Analysis of the exometabolome of the strain did not explain these effects.The strain was comprehensively characterized, including physiological, biochemical, and morphological traits. The complete genome of the strain was sequenced using Illumina HiSeq 4000 (2x150) and ONT and annotated using NCBI PGAP. Its genome has a size of 8 359 197 bp. GC content – 71.59%. Using antiSMASH 7.0, 35 biosynthetic clusters were revealed. The indices of digital DNA-DNA hybridization and orthoANI for all of the type strains with Streptomyces sp. ONU 561 are much lower than threshold values for the species separation. The obtained results, including a comparative analysis of the genome, indicate the possible affiliation of the strain Streptomyces sp. ONU 561 to a new species and the potential ability of these actinobacteria to synthesize previously unknown antibiotic compounds

    ПЕРИОПЕРАЦИОННЫЙ ПЕРИОД ПРИ ТРАНСПЛАНТАЦИИ СЕРДЦА С ВЫРАЖЕННОЙ ГИПЕРТРОФИЕЙ МИОКАРДА ЛЕВОГО ЖЕЛУДОЧКА

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    Use donor hearts with left ventricular hypertrophy (LVH) is controversial. This category of heart recipients has increasing risk of early graft failure. We proposed that heart transplantation (HT) with LVH ≥1.5 cm may be successful if performed in selective category patients from alternate transplant list. This study included 10 pati- ents (2 female and 8 male) at the age 26–62 (44 ± 3), who needed urgent HT. This study showed that recipients with LVH ≥1.5 cm demanded more high and long inotropic support with adrenalin and dopamine, more fre- quent use of levosimendan infusion (in 40% of cases) and intraaortic balloon conterpulsation (in 50% of cases). However we didn’t observed any difference in survival rate (90.0% vs 89.0%) and ICU time (4.8 ± 0.6 days vs 4.1 ± 0.4 days) between HT recipients with and without LVH. Our study showed that HT from donor with LVH ≥1.5 cm may be performed in patients, demanding urgent HT, with acceptable early posttransplant results. Дефицит донорских сердец делает допустимым ТС от доноров с гипертрофией миокарда левого желудочка (ГМЛЖ) больным, нуждающимся в неотложной пересадке сердца. Настоящее исследование проводилось с целью выявления особенностей тактики кондиционирования сердечных доноров, анестезиологического пособия и периоперационной интенсивной терапии при трансплантации донорского сердца с толщиной миокарда левого желудочка 1,5 сантиметра и более. В исследование включили 10 больных (2 женщины и 8 мужчин) в возрасте 26–62 (44 ± 3) года с высоким риском летального исхода вследствие быстрого прогрессирования основного заболевания и возможного развития жизнеугрожающих полиорганных, ин- фекционных, тромбоэмболических и других осложнений. Исследование продемонстрировало, что тре- буется около 3 суток для восстановления адекватной насосной функции трансплантированного сердца с ГМЛЖ, после чего течение посттрансплантационного периода не отличается от реципиентов без ГМЛЖ донорского сердца. У реципиентов с ГМЛЖ применили более высокие (р < 0,05) дозировки адреналина и допамина. Кардиотоническая терапия была более (р < 0,05) длительной по сравнению с реципиентами без ГМЛЖ. Инфузию левосимендана (100 нг/кг/мин) в качестве меры лекарственной поддержки насосной функции сердечного трансплантата использовали у 4 (40%) из 10 реципиентов с ГМЛЖ ≥ 1,5 см. В 50% (n = 5) наблюдений потребовалась механическая поддержка кровообращения (во всех случаях ВАБК). 30-дневная выживаемость реципиентов после ТС с ГМЛЖ составила 90%. Таким образом, применение комплекса лечебных мероприятий, направленных на восстановление адекватной насосной функции сер- дечного трансплантата и коррекцию мультиорганных нарушений, делает возможным успешное выполне- ние пересадки сердца с ГМЛЖ ≥1,5 см реципиентам, нуждающимся в неотложной трансплантации.

    Evolutional and clinical implications of the epigenetic regulation of protein glycosylation

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    Protein N glycosylation is an ancient posttranslational modification that enriches protein structure and function. The addition of one or more complex oligosaccharides (glycans) to the backbones of the majority of eukaryotic proteins makes the glycoproteome several orders of magnitude more complex than the proteome itself. Contrary to polypeptides, which are defined by a sequence of nucleotides in the corresponding genes, glycan parts of glycoproteins are synthesized by the activity of hundreds of factors forming a complex dynamic network. These are defined by both the DNA sequence and the modes of regulating gene expression levels of all the genes involved in N glycosylation. Due to the absence of a direct genetic template, glycans are particularly versatile and apparently a large part of human variation derives from differences in protein glycosylation. However, composition of the individual glycome is temporally very constant, indicating the existence of stable regulatory mechanisms. Studies of epigenetic mechanisms involved in protein glycosylation are still scarce, but the results suggest that they might not only be important for the maintenance of a particular glycophenotype through cell division and potentially across generations but also for the introduction of changes during the adaptive evolution

    The Electrochemical Performance and Applications of Several Popular Lithium-ion Batteries for Electric Vehicles - A Review

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    The Lithium-ion battery is one of the most common batteries used in Electric Vehicles (EVs) due to the specific features of high energy density, power density, long life span and environment friendly. With the development of lithium-ion battery technology, different materials have been adopted in the design of the cathodes and anodes in order to gain a better performance. LiMn2O4LiMn_{2}O_{4} , LiNiMnCoO2LiNiMnCoO_{2} , LiNiCoAlO2LiNiCoAlO_{2} , LiFePO4LiFePO_{4} and Li4Ti5O12Li_{4}Ti_{5}O_{12} are five common lithium-ion batteries adopted in commercial EVs nowadays. The characteristics of these five lithium-ion batteries are reviewed and compared in the aspects of electrochemical performance and their practical applications

    Клиническая эффективность и безопасность применения ингаляционного простациклина у больных с инфекцией, вызванной SARS-CoV-2 (проспективное сравнительное исследование)

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    Aim. In this study we evaluated clinical effectiveness and safety of nebulized prostacyclin in patients with Novel Coronavirus Disease (SARS-CoV-2). Materials and methods: We have included 44 male patients with moderate PCR confirmed SARS-CoV-2 infection in this study. Control group consisted of 23 patients treated with nebulized prostacyclin (PGI2). besides standard therapy. We compared intensiveness and duration of infectious intoxication syndrome, duration of fever, cough as well as SpO2 level, complete blood count and chemokine status values. Results: Statistically significant difference in duration of fever, cough, intensiveness and duration of infectious intoxication syndrome were observed. Lymphocyte and platelet counts were significantly higher in control group We have also noticed significantly lower level of proinflammatory mediators and C4-complement component in control group. Only 1 adverse effect associated with inhaled prostacyclin was reported. Conclusion. Nebulized prostacyclin showed therapeutic efficacy and good safety profile in adults with moderate COVID-19.Цель: оценка клинической эффективности и безопасность ингаляционного простациклина у пациентов с новой коронавирусной инфекцией (SARS-CoV-2). Материалы и методы: в исследование были включены 44 пациента мужского пола с подтвержденной новой коронавирусной инфекцией среднетяжелого течения. Опытную группу составили 23 пациента, которым, помимо стандартной терапии, был назначен ингаляционный простациклин (PGI2). Клиническая эффективность илопроста была оценена по длительности и выраженности общеинфекционных синдромов (интоксикации, лихорадки), длительности кашля, уровню насыщения крови кислородом, значениям параметров общеклинического анализа крови, показателю иммунологического статуса пациентов. Результаты: получено статистически значимое снижение длительности лихорадки, продолжительности кашля, выраженности и длительности синдрома общей инфекционной интоксикации в опытной группе. Также отмечено, что у этих пациентов средние значения количества лимфоцитов, тромбоцитов достоверно увеличивалось, а значение СОЭ снижалось. Средние значения провоспалительных цитокинов, хемокинов, а также С4-компонента комплемента были статистически значимо ниже, чем у больных COVID-19 в группе сравнения. Нежелательные реакции, связанные с инга ляционной терапией простациклином, были отмечены в 1 наблюдении. Заключение: показана терапевтическая эффективность и хороший профиль безопасности ингаляционного простациклина у пациентов с COVID-19 средней степени тяжести

    Как придать импульс развитию российской экономики: приоритеты действий (предложения к Основным направлениям деятельности Правительства РФ до 2024 г.)

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    This report was prepared by the staff of the Institute for Economic Forecast of the Russian Academy of Sciences and the Financial University under the Government of the Russian Federation. It gives suggestions to implement priority measures to facilitate the transfer the Russian economy to the direction defined by the Decree of the President of the Russian Federation (est. May 7, 2018). The report also highlights priority directions of the economic policy, primarily in investment activity, development of the domestic market, as well as financial and organizational support for the suggested actions.В докладе, подготовленном сотрудниками Института народнохозяйственного прогнозирования РАН и Финансового университета при Правительстве Российской Федерации, представлены предложения по первоочередным мерам, способствующим переводу российской экономики на траекторию, определенную Указом Президента Российской Федерации от 07.05.2018. Выделены приоритетные направления  экономической политики, прежде всего, в инвестиционной деятельности, развитии внутреннего рынка, а также финансового и организационного обеспечения предлагаемых мер
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