Extraction processing of concentrated solutions of uranyl nitrate with high impurities content

Process flowsheet of recycling uranium concentrated solutions with its purification from insoluble impurities of iron, silicon, molybdenum, calcium oxides and hydroxides and soluble impurities with application of centrifugal extractors cascade has been developed and suggested for commercial introduction. The process was carried out at extractant saturation (30 % tributyl phosphate in hydrocarbon diluent) in extraction assembly lower than a limiting level (85...95 g/l) and in wash assembly - at limiting saturation (up to 120 g/l). As a result the waste uranium content in water-tail solutions 0,01...0,04 g/l and minimal content of impurities in re-extractors is provide

Excitons in type-II quantum dots: Finite offsets

Quantum size effects for an exciton attached to a spherical quantum dot are calculated by a variational approach. The band line-ups are assumed to be type-II with finite offsets. The dependence of the exciton binding energy upon the dot radius and the offsets is studied for different sets of electron and hole effective masses

Асинхронная репликация у онкологических больных

Epigenetics is a science studying mechanisms of heritable changes in gene function that occur without a change in the DNA sequence. One of the most important marks of epigenetic misbalance of cell genome is an replication asynchrony of genes with biallelic expression. Interphase fluorescence in situ hybridization (I-FISH) in phytohaemagglutinin-stimulated lymphocytes of peripheral blood is a proper method of estimation of aberrant DNA replication time e. g. DNA replication asynchrony. In this review we analyzed reports referring to asynchronous DNA replication of biallelically expressed genes in lymphocytes of peripheral blood of cancer patients. Analysis shows the DNA replication asynchrony is a nonspecific tumor marker observing both in tumor cells and lymphocytes of peripheral blood in oncohematological patients and patients with solid tumors. It’s stated the frequency of lymphocytes with asynchronous DNA replication of studied genes in cancer patients is increased significantly compares with healthy donors and is enhanced during malignance process. It gives the opportunity of potential using asynchronous replication as molecular genetic marker for cancer patients early revealing.Эпигенетика – наука об обратимых наследственных изменениях функционирования гена, которые происходят без изменений в нуклеотидной последовательности ДНК. Один из важнейших маркеров нарушений эпигенетической регуляции генома клетки – асинхронность репликации ДНК биаллельно экспрессирующихся генов. Удобным методом оценки нарушения синхронности репликации (асинхронной репликации) в культивированных лимфоцитах периферической крови человека, как правило, является интерфазная флуоресцентная in situ гибридизация (I-FISH). В обзоре проведен анализ работ, направленных на изучение асинхронной репликации биаллельно экспрессирующихся генов в лимфоцитах периферической крови онкологических больных. Этот анализ показал, что асинхронная репликация – неспецифический маркер злокачественных новообразований и наблюдается как у онкогематологических больных, так и у пациентов с солидными опухолями, причем не только в клетках опухоли, но и в лимфоцитах периферической крови. Проведенный анализ продемонстрировал, что встречаемость лимфоцитов с асинхронной репликацией изученных генов у онкологических больных достоверно повышена по сравнению со здоровыми лицами и увеличивается в процессе малигнизации (злокачественного перерождения) заболеваний. Это дает потенциальную возможность использовать асинхронную репликацию как молекулярно-генетический маркер для раннего выявления лиц с онкологическими заболеваниями

A cytogenetic follow-up of some highly irradiated victims of the Chernobyl accident

Altres ajuts: The authors wish to thank INTAS (research grant no. 97-1152) for financial support for this workA follo w-up of 10 highly irradiated men, mostly reactor crew, from the Chernobyl accident is described. Their pre-accident medical conditions and relevant medical status approximately 10-13 y later are listed. A comparison is made between estimates of their average whole-body penetrating radiation doses derived from several biological parameters. First estimates were based on their presenting severity of prodromal sickness, early changes in blood cell counts and dicentric chromosome aberrations in lymphocytes. In three cases ESR measurements on tooth enamel were also made. Retrospective dosimetry using FISH translocations was attempted 10-13 y later. This showed good agreement for those patients with the lower earlier dose estimates, up to about 3 Gy. For the others, extending up to about 12 Gy, the translocations indicated lower values, suggesting that in these cases translocations had somewhat declined. Repeated chromosomal examinations during the follow-up period showed an expected decline in dicentric frequencies. The pattern of decline was bi-phasic with a more rapid first phase, with a half-life of ∼4 months followed by a slower decline with half-lives around 2-4 y. The rapid phase persisted for a longer time in those patients who had received the highest doses. 10-13 y later dicentric levels were still above normal background, but well below the translocation frequencies

Mechanisms of the Vertical Secular Heating of a Stellar Disk

We investigate the nonlinear growth stages of bending instability in stellar disks with exponential radial density profiles.We found that the unstable modes are global (the wavelengths are larger than the disk scale lengths) and that the instability saturation level is much higher than that following from a linear criterion. The instability saturation time scales are of the order of one billion years or more. For this reason, the bending instability can play an important role in the secular heating of a stellar disk in the $z$ direction. In an extensive series of numerical $N$-body simulations with a high spatial resolution, we were able to scan in detail the space of key parameters (the initial disk thickness $z_0$, the Toomre parameter $Q$, and the ratio of dark halo mass to disk mass $M_{\rm h} / M_{\rm d}$). We revealed three distinct mechanisms of disk heating in the $z$ direction: bending instability of the entire disk, bending instability of the bar, and heating on vertical inhomogeneities in the distribution of stellar matter.Comment: 22 pages including 8 figures. To be published in Astronomy Letters (v.29, 2003

Upper limits on the isotropic diffuse flux of cosmic PeV photons from Carpet-2 observations

Isotropic diffuse gamma-ray flux in the PeV energy band is an important tool for multimessenger tests of models of the origin of high-energy astrophysical neutrinos and for new-physics searches. So far, this flux has not yet been observed. Carpet-2 is an air-shower experiment capable of detecting astrophysical gamma rays with energies above 0.1 PeV. Here we report the upper limits on the isotropic gamma-ray flux from Carpet-2 data obtained in 1999-2011 and 2018-2022. These results, obtained with the new statistical method based on the shape of the muon-number distribution, summarize Carpet-2 observations as the upgraded installation, Carpet-3, starts its operation.Comment: 5 pages, 3 figures, JETPL.cls; V2: references added, version accepted by JETP Letter

Асинхронная репликация генов AURKA и TP53 у больных солитарным раком желудка и больных с полинеоплазиями

Background. The correct genome replication is essential for normal cell division to guarantee that genetic information comes changeless through the next cells generations. DNA replication is a strictly regulated and synchronous process and its disturbances could result to mutations appearances. Aberrant time of DNA replication affects on gene expression causes changes of epigenetic modifications and influences on increasing the structural rearrangements leading to enhanced genome disbalance. Replication time failure as asynchronous replication is common for cancerogeneses. The objective of our study was the assessment of asynchronous replication levels in patients with gastric cancer and patients with multiple tumors.Materials and methods. Fluorescence in situ hybridization (FISH) was used for the asynchronous replication of AURKA and TP53 genes analyses. Interphase FISH on lymphocytes of peripheral blood of 37 healthy donors, 19 patients with non-cancer gastrointestinal pathologies, 68 patients with solitary gastric cancer and 39 patients with multiple tumors having gastric cancer and other second synchronous or metachronous tumor was carried out.Results. Values of lymphocytes with asynchronous replication for AURKA were 19.8 ± 0.5 % for control group, 24.7 ± 0.4 % for non-cancer patients, 32.5 ± 0.5 % for gastric cancer patients, 39.5 ± 0.6 % for patients with multiple tumors and 17.3 ± 0.5, 19.5 ± 0.7, 26.1 ± 0.7 and 32.5 ± 0.6 % for TP53 respectively. Differences between cell populations of examined groups had statistical significance with p <0.01 for both studied gene. Also there was statistical difference between gastric cancer patients having distant metastases and gastric cancer patients without metastases for AURKA (34.4 ± 1.0 % vs. 31.7 ± 0.6 %; p = 0.02).Conclusion. High lymphocytes with asynchronous replication level in oncological patients could serve as potential marker of second tumor or possible metastatic process including the earliest stage of it. Введение. Правильная репликация генома важна для нормального клеточного деления как гарантия неизменности передачи генетической информации. ДНК-репликация является строго регулируемым и синхронизированным процессом, нарушения в котором могут приводить к возникновению мутаций. Нарушения во времени ДНК-репликации влияют на экспрессию генов, вызывают изменения в эпигенетических модификациях и влияют на увеличение частоты структурных перестроек, что приводит к нестабильности генома. Нарушения во времени репликации (асинхронная репликация) часто сопровождают развитие рака.Цель исследования – изучение встречаемости лимфоцитов периферической крови с асинхронной репликацией генов AURKA и TP53 у больных раком желудка и больных с полинеоплазиями.Материалы и методы. Асинхронность репликации генов AURKA и TP53 определяли методом флуоресцентной in situ гибридизации (FISH) в лимфоцитах периферической крови. Интерфазный FISH-анализ был выполнен у 37 здоровых доноров, 19 больных с неопухолевой патологией желудочно-кишечного тракта, 68 больных солитарным раком желудка и 39 пациентов с полинеоплазиями, т. е. с раком желудка и второй синхронной или метахронной опухолью. Результаты. Доля лимфоцитов с асинхронной репликацией гена AURKA составила 19,8 ± 0,5 % для контрольной группы, 24,7 ± 0,4 % для группы с неопухолевой патологией, 32,5 ± 0,5 % для группы больных раком желудка и 39,5 ± 0,6 % для группы с полинеоплазиями; для гена TP53 – 17,3 ± 0,5; 19,5 ± 0,7; 26,1 ± 0,7 и 32,5 ± 0,6 % соответственно. Различия между всеми обследованными группами были статистически значимы по обоим исследованным генам (p <0,01). Больные раком желудка с метастазами имели бόльшую долю лимфоцитов с асинхронной репликацией гена AURKA, чем пациенты без метастазов (34,4 ± 1,0 % против 31,7 ± 0,6; p = 0,02).Заключение. Высокий уровень лимфоцитов с асинхронной репликацией у онкологических больных может быть потенциальным маркером второй опухоли или возможного метастатического процесса, в том числе и на начальном уровне.