On the Electron-Electron Interactions in Two Dimensions

In this paper, we analyze several experiments that address the effects of electron-electron interactions in 2D electron (hole) systems in the regime of low carrier density. The interaction effects result in renormalization of the effective spin susceptibility, effective mass, and g*-factor. We found a good agreement among the data obtained for different 2D electron systems by several experimental teams using different measuring techniques. We conclude that the renormalization is not strongly affected by the material or sample-dependent parameters such as the potential well width, disorder (the carrier mobility), and the bare (band) mass. We demonstrate that the apparent disagreement between the reported results on various 2D electron systems originates mainly from different interpretations of similar "raw" data. Several important issues should be taken into account in the data processing, among them the dependences of the effective mass and spin susceptibility on the in-plane field, and the temperature dependence of the Dingle temperature. The remaining disagreement between the data for various 2D electron systems, on one hand, and the 2D hole system in GaAs, on the other hand, may indicate more complex character of electron-electron interactions in the latter system.Comment: Added refs; corrected typos. 19 pages, 7 figures. To be published in: Chapter 19, Proceedings of the EURESCO conference "Fundamental Problems of Mesoscopic Physics ", Granada, 200

Нарушение метилирования ДНК при злокачественных новообразованиях

DNA methylation is a chromatin modification that plays an important role in the epigenetic regulation of gene expression. Changes in DNA methylation patterns are characteristic of many malignant neoplasms. DNA methylation is occurred by DNA methyltransferases (DNMTs), while demethylation is mediated by TET family proteins. Mutations and changes in the expression profile of these enzymes lead to DNA hypo- and hypermethylation and have a strong impact on carcinogenesis. In this review, we considered the key aspects of the mechanisms of regulation of DNA methylation and demethylation, and also analyzed the role of DNA methyltransferases and TET family proteins in the pathogenesis of various malignant neoplasms.During the preparation of the review, we used the following biomedical literature information bases: Scopus (504), PubMed (553), Web of Science (1568), eLibrary (190). To obtain full-text documents, the electronic resources of PubMed Central (PMC), Science Direct, Research Gate, CyberLeninka were used. To analyze the mutational profile of epigenetic regulatory enzymes, we used the cBioportal portal (https://www.cbioportal.org / ), data from The AACR Project GENIE Consortium (https://www.mycancergenome.org / ), COSMIC, Clinvar, and The Cancer Genome Atlas (TCGA).Метилирование ДНК представляет собой модификацию хроматина, которая играет важную роль в эпигенетической регуляции экспрессии генов. Изменение паттернов метилирования ДНК характерно для многих злокачественных новообразований. Метилирование ДНК осуществляется ДНК-метилтрансферазами (DNMTs), в то время как деметилирование происходит под действием метилцитозиновых диоксигеназ, или белков семейства TET. Мутации и изменение профиля экспрессии данных ферментов, приводящие к гипо- и гиперметилированию ДНК, могут оказывать сильное влияние на канцерогенез.В обзоре рассмотрены ключевые аспекты механизмов регуляции метилирования и деметилирования ДНК, а также проведен анализ роли ДНК-метилтрансфераз и белков семейства ТЕТ в патогенезе различных злокачественных новообразований.При подготовке обзора были использованы информационные базы биомедицинской литературы Scopus (504), PubMed (553), Web of Science (1568), eLibrary (190), для получения полнотекстовых документов – электронные ресурсы PubMed Central (PMC), Science Direct, Research Gate, КиберЛенинка, для анализа мутационного профиля эпигенетических регуляторных ферментов – портал cBioportal (https://www.cbioportal.org / ), данные проекта The AACR Project GENIE Consortium (https://www.mycancergenome.org / ), базы данных COSMIC, Clinvar и Атласа генома рака (The Cancer Genome Atlas, TCGA)

LAPAROSCOPIC ACCESS IN THE TREATMENT OF ADHESIVE INTESTINAL OBSTRUCTION

OBJECTIVE. Improvement of surgical treatment of patients with adhesive intestinal obstruction.MATERIAL AND METHODS. This article shows the analyzing results of surgical treatment of 73 patients with adhesive intestinal obstruction. The main group consisted of patients with adhesive intestinal obstruction; adhesiolysis was performed for them laparoscopically. The comparison group included patients who underwent laparotomy.RESULTS. Conversions to laparotomy were not noted in the main group. There is no significant difference in the number of complications in the compared groups. In the main group, the duration of the operative intervention was significantly less, the level of postoperative pain was lower, the recovery of intestinal peristalsis was faster, the hospital stay was shorter (p<0.05).CONCLUSION. Laparoscopic access in comparison with laparotomy for patients with adhesive intestinal obstruction has several advantages, and can be used in this category of patients

Notebookof self-training in the discipline «Human Anatomy». Part III

The self-study notebook is designed to improve the knowledge and practical skills of students of medical and dental faculties