Magnetostructural correlations in BiFeO3-based multiferroics

This work was supported by funds from FEDER (Programa Operacional Factores de Competitividade COMPETE) and from FCT-Fundaça˜o para a Cieˆncia e a Tecnologia under the project UID/FIS/04564/2016. V. A. K. is grateful to Fundaça˜o para a Cieˆncia e a Tecnologia for financial support through the FCT Investigator Programme (project IF/00819/2014). D. V. K. is grateful to BRFFR (grant F16R-066). Access to the TAIL-UC facility funded under QREN-Mais Centro project ICT_2009_02_012_1890 is gratefully acknowledged

Scattered Light Measurement for the Birefringence Distribution Estimations

The technique based on the digital processing of recorded scattered light distribution enabling for the measurement of the birefringence profile in non-uniform anisotropic materials was proposed. Keywords: measurement technique, birefringence distribution, scattered light, tempered glas

Crystal and magnetic structure transitions in bimno3+δ ceramics driven by cation vacancies and temperature

The crystal structure of BiMnO$_{3+δ}$ ceramics has been studied as a function of nominal oxygen excess and temperature using synchrotron and neutron powder diffraction, magnetometry and differential scanning calorimetry. Increase in oxygen excess leads to the structural transformations from the monoclinic structure (C2/c) to another monoclinic (P2$_{1}$/c), and then to the orthorhombic (Pnma) structure through the two-phase regions. The sequence of the structural transformations is accompanied by a modification of the orbital ordering followed by its disruption. Modification of the orbital order leads to a rearrangement of the magnetic structure of the compounds from the long-range ferromagnetic to a mixed magnetic state with antiferromagnetic clusters coexistent in a ferromagnetic matrix followed by a frustration of the long-range magnetic order. Temperature increase causes the structural transition to the nonpolar orthorhombic phase regardless of the structural state at room temperature; the orbital order is destroyed in compounds BiMnO$_{3+δ}$ (δ ≤ 0.14) at temperatures above 470 °C

Mn substitution-modified polar phase in the Bi1-xNdxFeO3 multiferroics

Room-temperature crystal structure and multiferroic properties of the Bi0.92Nd0.08Fe1-xMnxO3 (x <= 0.3) ferromanganites have been studied to reveal the effect of Mn doping on the magnetic and ferroelectric behaviors of the lanthanide-modified compound representing a polar (space group R3c) predominantly antiferromagnetic phase of the Bi(1-x)Ln(x)FeO(3) perovskites. B-site substitution tends to suppress existing polar displacements and induces a ferroelectric-to-antiferroelectric transition near x = 0.2. The threshold concentration inducing the structural transformation does not coincide with that required to change the dominant magnetic interaction, so a weak ferromagnetic/ferroelectric state unusual for the Bi(1-x)Ln(x)FeO(3) and BiFe1-xMnxO3 series appears in the intermediate concentration range near the polar/nonpolar phase boundary. (C) 2013 AIP Publishing LLC

Peculiarities of the crystal structure evolution of Bifeo3-batio3 ceramics across structural phase transitions

Evolution of the crystal structure of ceramics BiFeO3-BaTiO3 across the morphotropic phase boundary was analyzed using the results of macroscopic measuring techniques such as X-ray diffraction, differential scanning calorimetry, and differential thermal analysis, as well as the data obtained by local scale methods of scanning probe microscopy. The obtained results allowed to specify the concentration and temperature regions of the single phase and phase coexistent regions as well as to clarify a modification of the structural parameters across the rhombohedral-cubic phase boundary. The structural data show unexpected strengthening of structural distortion specific for the rhombohedral phase, which occurs upon dopant concentration and temperature-driven phase transitions to the cubic phase. The obtained results point to the non-monotonous character of the phase evolution, which is specific for metastable phases. The compounds with metastable structural state are characterized by enhanced sensitivity to external stimuli, which significantly expands the perspectives of their particular use. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção, INCT-EN: UID/04564/2020, UIDB/50011/2020, UIDP/50011/2020Russian Science Foundation, RSF: 18-19-00307Funding: This work was supported by the RSF (project #18-19-00307). Investigations performed at the Center for Physics of the University of Coimbra were supported by Fundação para a Ciência e a Tecnologia (project UID/04564/2020). M.V.S. acknowledges Russian academic excellence project “5-100” for Sechenov University. Part of work done at the University of Aveiro was developed within the scope of the project CICECO-Aveiro Institute of Materials, refs. UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC

Antiferromagnet-ferromagnet phase transition in lightly doped manganites

Magnetic and structural phase diagrams of the La₀.₈₈MnOx, La₁₋xSrx(Mn₁₋x/₂Nbx/₂)O₃, Nd₁₋xCaxMnO₃, and Bi₁₋xCaxMnO₃ series constructed on the basis of x-ray, neutron powder diffraction, Young’s modulus, magnetization and resistivity measurements are presented. It is shown that the main factor controlling the antiferromagnet–ferromagnet phase transition in the manganites is a type of an orbital state. The results are discussed in the framework of structurally driven magnetic phase separation model

Эффективность противовирусной терапии рецидива хронического гепатита С у пациентов, перенесших трансплантацию печени

In the article the analysis data of observation and treatment recurrence hepatits C after liver transplantation. When performing operations on the background of the current active infection relapse is inevitable, and progression is fast. The effectiveness of antiviral therapy for immunosuppression is low. End-of-treatment response was achieved in 55,5%. Sustained virologic response was achieved in 42.9%. In one-third cases treatment was discontinuation because of adverse events.В статье проанализирован собственный опыт наблюдения и лечения рецидива хронического гепатита С у пациентов после трансплантации печени. При выполнении операции на фоне активно текущей инфекции рецидив заболевания неизбежен, а прогрессия быстрее. Эффективность противовирусной терапии на фоне иммуносупрессии ниже, чем у имуннокомпетентных лиц. Частота непосредственного вирусологического ответа составила 55,5%. Устойчивый вирусологический ответ достигнут в 42,9% случаев. Треть пациентов из-за развившихся нежелательных явлений не смогли получить полный курс лечения

Strong magneto-elastic coupling and polar properties in orthorhombic Eu1-xYxMnO3 manganite

This work reports an experimental investigation of the magneto-elastic coupling and polarization character of magnetic phases of the orthorhombic Eu1-xYxMnO3 system at low temperatures. The temperature dependence of the polarization reversal curves clearly reveals the existence of a reentrant improper ferroelectric phase for x = 0.2 and 0.3. Although a ferroelectric phase is also stable for x = 0.4, we have no experimental evidence that it vanishing at finite temperatures. From these results and those obtained from other experimental techniques, the corresponding (x,T) phase diagram was traced, yet yielding significant differences with regard to previous reports. An expressive magneto-elastic coupling is revealed by changes observed in both Mn-O bond lengths and Mn-O1-Mn bond angle at the magnetic phase transitions, obtained by temperature dependence of synchrotron x-ray diffraction experiments. Furthermore, signatures of the lattice deformations across the magnetic phase transitions were evidenced by anomalies in the temperature dependence of the lattice mode involving rotations of the MnO6 octahedra. These anomalies confirm the important role of the spin-phonon coupling in these materials.Comment: 12 Figures, 2 Table

Создание короткоплодных партенокарпических линий огурца гладкого типа

Relevance. Obtaining modern cucumber hybrids is impossible without the constant involvement of genetically new sources in the breeding process. One of the most important tasks in the issue of creating new heterotic cucumber hybrids is to obtain, and in the future, selection for hybrid crossings, parental lines with the most important economically valuable traits. Research is aimed at obtaining new short-fruited cucumber lines with a smooth type of fruit in order to obtain hybrids with their help that combine resistance to powdery mildew for the “pm” and “pmh” genes, tolerance to the zucchini yellow mosaic virus for the “zymv” genes in combined with high yields, the possibility of growing them not only in unheated film greenhouses, but also in glazed greenhouses.Methods. This article presents two schemes for obtaining parental forms using the example of creating four cucumber lines with a short, smooth fruit. Their comparative characteristics and description of new hybrids created with the participation of the studied linear material are carried out. Materials and methods. The main studies were carried out in 2013-2020 on the basis of the Pumpkin Cultures Laboratory of the Krymsk Breeding Center "Gavrish" of the Research Institute of Vegetable Breeding (Krymsk, Krasnodar Territory). The research material is F1 hybrids and selection samples of parthenocarpic cucumber with a smooth type of fruit of various origins (34 samples in total) from the NIISOK collection. The work used traditional methods for assessing selection-significant traits and modern methods of molecular labeling. The purpose of the work is to compare two schemes for obtaining short-fruited cucumber forms, to evaluate the created lines and hybrid combinations with their participation in terms of a complex of economically valuable traits.Results. The result of the work was the creation of new hybrid combinations based on the obtained lines, two of which are included in the State Register of Breeding Achievements. These are F1 Ministar (F1 1600/16) and F1 Promini (F1 1995/16).Получение современных гибридов огурца невозможно без постоянного привлечения генетически новых источников в селекционный процесс. Одной из важнейших задач в вопросе создания новых гетерозисных гибридов огурца является получение, а в дальнейшем, подбор для гибридных скрещиваний, родительских линий с важнейшими хозяйственно ценными признаками. Исследования направлены на получение новых короткоплодных линий огурца с гладким типом плода с целью получения c помощью них гибридов, сочетающих в себе устойчивость к настоящей мучнистой росе по генам «pm» и «pmh», толерантность к вирусу желтой мозаики цуккини по генам «zymv» в сочетании с высокой урожайностью, возможностью выращивания их не только в пленочных необогреваемых теплицах, но и в остекленных теплицах.Материалы и методы. В данной статье представлены две схемы получения родительских форм на примере создания четырех линий огурца с коротким гладким плодом. Проведена их сравнительная характеристика и описание новых гибридов, созданных с участием изучаемого линейного материала. Основные исследования проводили в 2013-2020 годах на базе лаборатории Тыквенные культуры Крымского селекционного центра «Гавриш» Научно-исследовательского института селекции овощных культур (г. Крымск, Краснодарский край). Материал исследований – гибриды F1 и селекционные образцы партенокарпического огурца с гладким типом плода различного происхождения (всего 34 образца) из коллекции НИИСОК. В работе использовали традиционные методы оценки селекционно значимых признаков и современные методы молекулярного маркирования. Цель работы – сравнить две схемы получения короткоплодных форм огурца, оценить созданные линии и гибридные комбинации с их участием по комплексу хозяйственно ценных признаков.Результаты. Результатом работы стало создание на базе полученных линий новых гибридных комбинаций, две из которых внесены в Государственный реестр селекционных достижений: F1 Министар (F1 1600/16) и F1 Промини (F1 1995/16)