Manifestation of interface anisotropy in CdTe quantum wells

Photoluminescence and polarized reflection spectra of quantum well structures with symmetric Cd$_{0.9}$Zn$_{0.1}$Te/CdTe/Cd$_{0.9}$Zn$_{0.1}$Te and asymmetric Cd$_{0.9}$Zn$_{0.1}$Te/CdTe/Cd$_{0.4}$Mg$_{0.6}$Te barriers were studied. The Stokes parameters of the reflected light from these structures were measured. In the structures with symmetric barriers, exciton resonances were found in the reflection spectra and were not present in the photoluminescence spectra. In structures with asymmetric barriers, in the region of exciton resonances, the phenomenon of light birefringence was detected, caused by a lower symmetry of the interfaces compared to the symmetry of bulk crystals. A discussion of both phenomena was given

Possibilities of use of means of ICT by preparation of final qualification works of students of pedagogical universities

In article problems of readiness of students and professors of mathematical faculties of pedagogical universities for use of means of information and communication technologies in the organization and carrying out researches within final qualification works of bachelors and masters are analyzedВ статье проанализированы проблемы готовности студентов и преподавателей математических факультетов педагогических университетов к использованию средств ИКТ при организации и проведении исследований в рамках выпускных квалификационных работ бакалавра и магистр

BLOOD LIPOPROTEINS AS A PLATFORM FOR TRANSPORT OF HYDROPHILIC AND HYDROPHOBIC COMPOUNDS

The paper discusses the transport functions of the main classes of blood plasma lipoproteins (LP) that are not associated with the metabolism of lipids that make up their composition. The aim of the study was to study the ability of various plasma LP fractions (very low (VLDL), low (LDL) and high density (HDL)) to interact with certain hydrophilic and hydrophobic compounds and show the role of LP as transport forms of xenobiotics in the organs and tissues of the body. Material and methods. The studies were performed with tritium-labeled cytochalasin B, benzylpenicillin, benzanthracene, benzo(a)pyrene, ultracentrifugation of human plasma LP fractions, column chromatography; in vivo experiments with intravenous injection of LP complexes with tritium-labeled benzanthracene were conducted. Results. The ability of various classes of LP to form complexes with hydrophilic (cytochalasin B, benzylpenicillin) and hydrophobic (benzanthracene, benzo(a)pyrene) compounds is shown by the method of ultracentrifugation. More than 50 % of the radioactivity of hydrophilic compounds in human blood plasma was represented in the composition of the LDL and HDL fractions, and in the composition of the VLDL fractions it was minimal – 6.3 and 5.1 %, respectively. A significant part of cytochalasin and benzylpenicillin was also present in the protein infranatant – 43.6 and 40.9 %, respectively. The distribution in blood plasma for hydrophobic (benzanthracene, benzo(a)pyrene) compounds was different. More than 80 % of the radioactivity was represented in the composition of the LP fractions. The polar protein infranatant contained 16.1 % of the radioactivity of benzantracene and 13.6 % of benzo(a)pyrene. The features of the lipophilic xenobiotics uptake by organs and tissues were shown in vivo experiments with intravenous injection of complexes of LP with tritium-labeled benzanthracene to rats. The highest specific radioactivity was found in the liver and adrenal glands after the intravenous injection of 3H-benzanthracene in the composition of VLDL and LDL. Twice less uptake of the labeled drug was observed in the testis and kidneys. Radioactivity decreased in the series: lungs,adipose tissue, thymus, heart, and spleen. A feature of the use of HDL as a platform for 3H-enzanthracene is the intense accumulation of lipophilic xenobiotics in steroid-producing organs: the adrenal glands and testis. Conclusion. The results obtained allow us to consider the real possibility of using blood plasma PL as transport platforms for hydrophilic and hydrophobic compounds into the cells of organs and tissues

Uptake of cholesterol esters being a part of the different fractions of blood plasma lipoproteins by rats organs and tissues

The paper deals with the functions of the main classes of blood plasma lipoproteins (LP) that are associated with the transport of cholesterol esters included in their composition. The aim of the study was to investigate the features of the uptake of cholesterol esters associated with plasma LP fractions (very low (VLDL), low (LDL), and high density LPs (HDL)) by rat organs and tissues, and to show the participation of various subfractions of HDL (HDL2 and HDL3) as specific cholesterol carriers in the main steroid-producing organs of rats.Material and methods. The in vivo studies with intravenous LP injection of 14C labeled cholesterol oleate (14C-OCh) associated with plasma LP fractions have been carried out.Results. Intravenous injection of a 14C-OCh) in the composition with VLDL led to the maximal mark uptake by the liver. Three times less uptake of labeled cholesterol was observed in the adrenal glands, testes and heart muscle. In other tissues radioactivity gradually decreased in the raw: spleen > lungs > kidneys > thyroid gland and adipose tissue. After the injection of 14C-OCh in the composition of LDL marked predominant uptake of the label by the adrenal glands, testes, and liver. A feature of the use of HDL as a carrier platform for 14C-OCh is the high accumulation of label in steroid-producing organs: the adrenal glands and testis. The dynamics of uptake of 14C-OCh in the composition of HDL by the adrenal glands and testes of rats in different time intervals after injection (30 min, 3, 6 and 12 h) was studied. Adrenal cells actively uptake 14C-OCh from HDL, as a result of which the radioactivity of the tissue increased rapidly and after 30 minutes almost reached its maximum. In contrast to the adrenal glands uptake of the testis was characterized by a gradual increase in radioactivity with a maximum of 6 hours and a rather sharp decrease to 12 hours from the beginning of the experiment. In vitro experiments showed the differences in the effect of HDL2 and HDL3 on the corticosterone production by the adrenal glands of rats.Conclusions. The paper presents the features of uptake of cholesterol esters by organs and tissues of rats depending on the used LP-transporter (VLDL, LDL, HDL). In addition, the results suggest that HDL3 subfraction may be the more preferred source of cholesterol for steroid synthesis in the adrenal cortex of rats compared to HDL2 subfraction

Information availability of official websites of the commissioners for the rights of the child: on the example of the Siberian federal district

В статье объясняется важность информационной доступности сайтов уполномоченных по правам ребенка как составляющей стратегии информирования населения, приводятся результаты анализа сайтов уполномоченных Сибирского федерального округа.The article explains the importance of information accessibility of the websites of the commissioners for the rights of the child as part of a strategy for informing the population, the results of the analysis of the websites of the commissioners of the Siberian Federal District are presented

A Modern View of Anomalies in the Metal Groups of the Periodic System of D.I.Mendeleev

The article is devoted to the 150th anniversary of the Periodic Table of Chemical Elements by D.I.Mendeleev. The fundamental law of nature, discovered by D.I.Mendeleev has anomalies and paradoxes associated with certain groups of metals. When studying the physical and chemical properties of complex metal compounds, many discrepancies can be found, namely, the location of elements in groups, which primarily relate to metals with different valences. By studying the approaches and methods for predicting the arrangement of chemical elements, it can be established that D.I.Mendeleev eliminated many differences for some metals during the formation of the Periodic system of chemical elements. D.I.Mendeleev developed a principle that excludes such errors when finding and discovering new elements. Analytical studies conducted by a Russian scientist helped to calculate the atomic masses and describe the properties of three elements not known at that time – «eka-boron», «eka-silicon», «eka-aluminum», the existence of which was proved and confirmed by subsequent discoveries of scandium, germanium, boron, and gallium. The paper provides a significant assessment of the forecasting of metals in various groups of the periodic system. Changes in the properties of some metals significantly influenced their location in the table of D.I.Mendeleev

Gamma Knife stereotactic radiosurgery for intraocular retinoblastoma: a 5-year experience

External beam radiotherapy (EBR) remained for a long time the only method of treatment in children with recurrent and resistant retinoblastoma (RB). This method often leads to serious complications, including the occurrence of secondary malignant tumors. Currently, EBR is used as second-line (salvage) therapy. There is no data in the literature of using Gamma Knife stereotactic radiosurgery (GKRS) in RB treatment.Purpose. To present 5-year experience of using GKRS in patients with RB.Material and methods. 16 children (17 eyes) were treated using GKRS in the period from 2015 to 2019. Mean patient age was 34.7 months (range, 12–114 months). The eyes were classified as group B (n=4), C (n=1), D (n=12). 3 children had the last eye. All patients received systemic and local chemotherapy, all types of local treatment modalities before using GKRS. Recurrent and resistant RB was the indication for GKRS. Marginal 50% mean dose was 22 Gу (range, 20–24 Gу), depending on tumour type and location. Radiation doses were evaluated accounting critical eye structures and the orbit bones.Results. Complete regression was achieved in 11 patients, partial in 2. Four patients underwent enucleation after GKRS. Indications for enucleation were retinoblastoma recurrence (n=2) and vitreous hemorrhage with total retinal detachment (n=2). 13 eyes were salvaged with no signs of keratopathy, uveitis or damage of orbital and surrounding tissues during mean follow-up 30.6 months (range, 7–60 months). Сomplications of different severity occurred in 13 patients, including vitreous hemorrhage in 6 patients, which was successfully treated both conservative (n=3) and using pars plana vitrectomy with simultaneous melphalan irrigation (n=3).Conclusion. The first experience of GKRS as an alternative to enucleation in patients with RB was proved to be reasonable and successful