Absence of room temperature ferromagnetism in bulk Mn-doped ZnO

Structural and magnetic properties have been studied for polycrystalline Zn_1-xMn_xO (x=0.02, 0.03, 0.05). Low-temperature (~500 oC) synthesis leaves unreacted starting ZnO and manganese oxides. Contrary to a recent report, no bulk ferromagnetism was observed for single-phase materials synthesized in air at temperatures above 900 oC. Single-phase samples show paramagnetic Curie-Weiss behavior.Comment: Accepted for publication in J. Appl. Phys., RevTeX, 3 pages, 4 figure

Structural and physical properties of SrMn1−xRuxO3SrMn_{1-x}Ru_xO_3 perovskites

We combine the results of magnetic and transport measurements with neutron diffraction data to construct the structural and magnetic phase diagram of the entire family of SrMn$_{1-x}$Ru$_{x}$O$_3$ ($0 \leqslant x \leqslant 1$) perovskites. We have found antiferromagnetic ordering of the C type for lightly Ru-substituted materials ($0.06 \leqslant x \leqslant 0.5$) in a similar manner to $R_{y}$Sr$_{1-y}$MnO$_3$ ($R$=La, Pr), due to the generation of Mn$^{3+}$ in both families of manganite perovskites by either $B$-site substitution of Ru$^{5+}$ for Mn$^{4+}$ or $A$-site substitution of $R^{3+}$ for Sr$^{2+}$. This similarity is driven by the same ratio of $d^4$ / $d^3$ ions in both classes of materials for equivalent substitution level. In both cases, a tetragonal lattice distortion is observed, which for some compositions ($0.06 \leqslant x \leqslant 0.2$) is coupled to a C-type AF transition and results in a first order magnetic and resistive transition. Heavily substituted SrMn$_{1-x}$Ru$_{x}$O$_3$ materials are ferromagnetic due to dominating exchange interactions between the Ru$^{4+}$ ions. Intermediate substitution ($0.6 \leqslant x \leqslant 0.7$) leads to a spin-glass behavior instead of a quantum critical point reported previously in single crystals, due to enhanced disorder.Comment: 9 pages, 10 figures, accepted for publication in Physical Review

Labor mobility in the system of employment strategies of the region’s population

The issue consideration of labor mobility as an employment strategy is relevant, because it is based on a growing understanding of the importance of labor mobility for the economic development of the country and its regions. The study purpose is to examine the place of labor mobility in the employment strategy of the population. The objectives are to study approaches to the labor mobility definition as an employment strategy, to analyze regional specifics in the labor mobility of the population, to determine the place of labor mobility in the employment strategy of the Tyumen region. General scientific, statistical and sociological methods were used in the research. The main study results are the identification of an increasing trend in the transformation of the population employment strategy and its reflection on the processes of labor mobility, grouped around changes in production and economic conditions. This provision defines not only the basis for the development of scientific discussion, but also the directions for further study of such issue

Clinical case of chemoresistant tuberculosis in the patient with tuberous sclerosis: difficulties of diagnosis, features of the course and treatment.

In the practical activities of a modern doctor, significant difficulties are noted in the diagnostics and proper management of patients with hereditary diseases due to the limited coverage of the population by genetic researches. For a long time, the patients with a variety of complaints are observed by doctors of various specialties, and the therapy often has little effect due to a lack of understanding of the true causes of pathological changes. The situation is complicated by case of a combined course of a hereditarily caused disease and some other disease of an infectious, non-infectious or tumor nature. The aim of the research was to study the characteristics of clinical manifestations, course of tuberculosis with resistance to anti-TB drugs in a patient with a rare hereditary disease from the group of phacomotoses - Bourneville-Pringle disease or tuberous sclerosis. This disease has a wide range of clinical manifestations, accompanied with the development of benign neoplasms in various organs and systems, damages to the skin, brain, organs of vision, lungs, kidneys, heart, as well as the musculoskeletal and endocrine system. It leads to development of various infectious and non-infectious pathologies in these organs. The article covers a 4-year period of observation of a young patient with late diagnosed tuberous sclerosis, suffering from pulmonary tuberculosis and tuberculosis of urinary system, includes the initial diagnosis of a specific disease, the course, the dynamics against received treatment and the development of relapse with the formation of resistance to anti-TB drugs. The difficulties in the management of tuberculosis in this patient were in the detection of numerous neoplasms and changes in the internal organs, in particular in the kidneys and lungs, which characterized tuberous sclerosis, on the one hand this contributed to untimely diagnosis of tuberculosis, and on the other hand – worsening the course and the progression of a specific process, as well as an unfavourable prognosis for recovery

ELISPOT assay of the SARS-CoV-2 specific T cells immune response

The COVID-19 pandemic has stimulated interest in the development of biotechnology, as well as in the search for new solutions in the diagnostics of immune processes. The response of immunoglobulins A, M and G had a significant role in the assessment of virus-specific immune responses. Later, it was understood that for a comprehensive assessment of adaptive immunity processes, it is reasonable to study its cellular component. One of the most affordable methods for assessing T cell immunity, which has proven itself in the diagnosis of other infectious diseases, such as latent tuberculosis infection, is IGRA ELISPOT.The aim of the study. To determine SARS-СoV-2 specific immune response of T lymphocytes in vitro in the peripheral blood of volunteers from various groups using IGRA ELISPOT method. We evaluated the applicability of the method to assess T cell immune response to infection and vaccination. In addition, we determined the duration of the maintenance period of the SARS-CoV-2 specific T cells immune response induced by vaccination.Materials and methods. The study was carried out on venous blood samples of volunteers from three groups: 1) hospital patients with COVID-19; 2) COVID-19 convalescents; 3) vaccinated against COVID-19. The T cell immune response was assessed using the TigraTest® SARS-CoV-2 test system, which determines in vitro the number of T cells secreting interferon-gamma in response to stimulation with SARS-СoV-2 peptides in two antigens panels: 1) peptides of the spike protein (S); 2) peptides of N, M, Orf3a and Orf7a proteins.Conclusion. The IGRA ELISPOT assay is a specific and sensitive tool in the assessment of T cell immunity to the SARS-CoV-2 virus. The method makes it possible to assess SARS-CoV-2 specific T cell responses induced both by natural encounter with the pathogen and by vaccination. It is advisable to use the method in routine practice for comprehensive assessment of immunity to SARS-CoV-2

ANATOMICAL AND TOPOGRAPHICAL FEATURES OF ANTERIOR VITREOUS CORTEX

Introduction. The vitreous body (VB) is limited  by anterior cortex (AC) layers, consisting of densely interconnected collagen fibers. There is no consensus regarding the structural AC organization and its relationship with the structures of the eyeball.Purpose. To study the anatomical and topographical features of the anterior cortical layers of VB.Material  and  methods.  We  developed an  original method  for contrasting the VB structures  using an ultra-fine Vitreokontrast suspension based on a water-insoluble inorganic salt of barium sulfate in the isotonic solution. The study was performed in 20 cadaveric donor eyes. the  original technology.  Dissection was carried  out  according to a proposed original technology. The scleral incision was made at a 4mm distance from the limbus along the circumference. Then we cut the sclera between the rectus muscles, then the petals of choroid and retina were formed, and also they were cut off. Then we cut the sclera between the rectus muscles, then the petals of choroid and retina were formed, and also cut them off. We stained the vitreous structures using the Vitreokontrast suspension with a sequential removal of the anterior cortex up to the posterior lens capsule.Results. After the cortex removal in the cadaveric donor eyes several membranous structures  (on an average of four) were detected with a covering the retrolental space with an ability to exfoliate, with sites of the attachment to the Wieger ligament and fibers of ciliary zonula and pars plana. After the removal of the membranous structures and their restaining a layer of vitreous fibers was contrasted on the posterior capsule of the lens in the area of Berger space projection. Conclusion. The study revealed no case of a true full anterior cortex detachment. The anterior cortex exfoliation occurred with the formation of a multilayer membranous structure, covering the posterior surface of lens and ciliary body.The presence of vitreous fibers closely associated with the posterior capsule of the lens in the projection area  of Berger space, allows to suppose a possibility of retrolental bag existence, one of walls of which is associated with the posterior lens capsule