Crystal chemistry search of multiferroics with the stereochemically active lone pair

On the basis of our previous studies of magnetoelectric ordering of BiFeO3, TbMnO3, TbMn2O5 and BiMn2O5 we formulate the crystal chemistry criteria for the search of multiferroics and reveal potential multiferroics Pb2Cu(OH)4Cl2, Pb5Cr3F19, Mn(SeO3){\dot}H2O and BiPbSr2MnO6 each containing the ion with a lone pair.Comment: 4 pages, 8 figures,submitted to J Supercond Nov Mag

Magnetoelectric ordering of BiFeO3 from the perspective of crystal chemistry

In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO3. It is generally accepted that the main reason of the ferroelectric distortion in BiFeO3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic beta-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity - its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO3 in the range from 945 C down to 25 C and found the couplings, which undergo the antiferromagnetic-ferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La3+.Comment: 18 pages, 5 figures, 3 table

Identification of New SRF Binding Sites in Genes Modulated by SRF Over-Expression in Mouse Hearts

Background To identify in vivo new cardiac binding sites of serum response factor (SRF) in genes and to study the response of these genes to mild over-expression of SRF, we employed a cardiac-specific, transgenic mouse model, with mild over-expression of SRF (Mild-O SRF Tg). Methodology Microarray experiments were performed on hearts of Mild-O-SRF Tg at 6 months of age. We identified 207 genes that are important for cardiac function that were differentially expressed in vivo. Among them the promoter region of 192 genes had SRF binding motifs, the classic CArG or CArG-like (CArG-L) elements. Fifty-one of the 56 genes with classic SRF binding sites had not been previously reported. These SRF-modulated genes were grouped into 12 categories based on their function. It was observed that genes associated with cardiac energy metabolism shifted toward that of carbohydrate metabolism and away from that of fatty acid metabolism. The expression of genes that are involved in transcription and ion regulation were decreased, but expression of cytoskeletal genes was significantly increased. Using public databases of mouse models of hemodynamic stress (GEO database), we also found that similar altered expression of the SRF-modulated genes occurred in these hearts with cardiac ischemia or aortic constriction as well. Conclusion and significance SRF-modulated genes are actively regulated under various physiological and pathological conditions. We have discovered that a large number of cardiac genes have classic SRF binding sites and were significantly modulated in the Mild-O-SRF Tg mouse hearts. Hence, the mild elevation of SRF protein in the heart that is observed during typical adult aging may have a major impact on many SRF-modulated genes, thereby affecting Cardiac structure and performance. The results from our study could help to enhance our understanding of SRF regulation of cellular processes in the aged heart

THE INVESTIGATION OF THE FAST ELECTRONS ENERGY DISTRIBUTION IN THE POSITIVE COLUMN AND NEGATIVE GLOW OF THE LOW PRESSURE HELIUM DISCHARGE

No abstract availabl

Ovarian endometriosis associated infertility: A modern view to the problem

This review summarizes current understanding of the pathogenesis of one of the most common forms of external genital endometriosis - ovarian endometrioma's. Due to their frequent occurrence in young women of reproductive age and extremely negative impact on the morphophysiological state of the ovaries, this disease makes a significant contribution to the structure of endometriosis-associated infertility. The main determinant of the negative effect of ovarian endometrioma's on reproductive function is a decrease in ovarian reserve, which can occur either due to the direct gonadotoxic effect of the endometriod cyst itself, or due to the unintentional removal of healthy ovarian tissue during surgery or the use of aggressive methods of electrosurgery. Hence, the question of methods for achieving hemostasis during surgery in terms of iatrogenic effects on healthy ovarian tissue is debatable. The management strategy for patients with infertility associated with ovarian endometriosis consists of two components: Surgical treatment and/or the use of assisted reproductive technologies. Laparoscopic cystectomy is indicated for cysts larger than 3 cm. Repeated surgical interventions in case of endometriosis do not improve fertility outcomes. Assisted reproductive technologies methods should be considered as a priority tactic in patients of older reproductive age with low ovarian reserve indicators or infertility duration of more than 2 years, as well as in cases of recurrent ovarian endometrioma's. Management of such patients must be personalized and take into account the age, state of the ovarian reserve, duration of infertility, stage and number of surgical interventions for this disease. © 2020 Gynecology. All rights reserved

Chronic endometritis in women with endometriosis-associated infertility

The article highlights modern ideas about the role of the endometrium in the genesis of reproductive failures. A crucial place of chronic endometritis in the structure of the endometrial infertility factor in endometriosis is noted. Given the frequent association of chronic endometritis and endometriosis, common features of these diseases have been identified. The characteristic of endometrial microbiota in infertility, chronic endometritis and endometriosis is given. An extremely important area of scientific research is precisely the interaction between the microbiota of the endometrium and its immunity, and not just the confirmation of the presence of microorganisms in the endometrium. The modern aspects of the etiology and pathogenesis of chronic endometritis and endometriosis are described. The main pathogenetic determinants of chronic endometritis are the failure of adaptation mechanisms to the constant effects of microbes and, as a consequence, the decrease and inferiority of the immune response and the development of autoimmune reactions. The modern paradigm for the development and progression of endometriosis involves the presence of bacterial contamination of the endometrium and the abdominal cavity, which in turn becomes a trigger for genetically-epigenetic modifications of cells, launching different cascades that underlie reproductive function disorders. The pathogenetically significant relationship between chronic endometritis and endometriosis is highlighted. It was revealed that chronic endometritis can be both a cause and a consequence of endometriosis. Disorders of the endometrial receptivity in chronic endometritis associated with endometriosis, their importance in the implementation of endometrial infertility are described. The important role of the microbiome in the formation of reproductive disorders is noted. © 2020 Gynecology. All rights reserved

Endometriosis-associated infertility: Options of combined therapy

Objective. To evaluate the effectiveness of using didrogesterone in combined therapy of endometriosis-associated. Patients and methods. The study included patients with infertility and verified diagnosis of ovarian endometriosis. The screening involved 108 women, of them 75 corresponded to the inclusion criteria. They were divided into two statistically comparable groups depending on a therapy option aimed at management of infertility. Group 1 (n = 36) included patients who underwent only surgical treatment, group 2 (n = 39) – women, who received combined therapy (surgical treatment + didrogesterone 10 mg/day from the 14th to the 25th day of the menstrual cycle for 6 months). The effectiveness of treatment was assessed by the incidence of clinical pregnancy within a 12-month follow-up period and, in case of pregnancy occurrence, by its outcomes. Results. As has been found, pregnancy incidence in women who received combined therapy exceeds by 1.6 times the results in the group of patients who underwent only surgical: 69.2 vs. 44.4%, p = 0.03. In combined treatment with the use of didrogesterone in the second phase of the cycle, the percentage of live births from the total number of pregnancies was significantly higher (by 1.3 times) as compared with group 1, and taking into consideration a greater incidence of pregnancy, the chances of successful management of infertility were by 2.4 times higher with inclusion of didrogesterone in therapy: 59.0% (23 of 39) in group 2 and only 25.0% (9 of 36) in group 1 (p = 0.0029). Conclusion. The use of didrogesterone as post-operative therapy and pregravid preparation of patients with endometriosis-associated infertility significantly improves the effectiveness of treatment and reproductive outcomes. © 2020, Dynasty Publishing House. All rights reserved