142 research outputs found

    Local Magnetohydrodynamic Characteristics of the Plasma Stream generated by MPC

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    This paper investigates the spatial distributions of electrical current which flows inside the plasma stream generated by a magnetoplasma compressor (MPC). Two different modes of MPC operation with different gas supply scenarios have been applied in the experiments presented here. The first is the operation mode with a pulse injection of xenon into the interelectrode space, and the second is the operation mode with residual helium in the chamber and local injection of xenon directly into the compression zone. The maximum value of the electric current observed outside the MPC channel is 15 ÷ 20% of the total discharge current. Electric current vortices were discovered in the plasma stream. The amplitude of the current in the vortices reaches 50% of the total discharge current. The maximum EUV radiation power was measured in the mode of MPC operation with local xenon injection. Power in the wave range 12.2 ÷ 15.8 nm achieves up to 16 ÷ 18 kW

    Local Magnetohydrodynamic Characteristics of the Plasma Stream generated by MPC

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    This paper investigates the spatial distributions of electrical current which flows inside the plasma stream generated by a magnetoplasma compressor (MPC). Two different modes of MPC operation with different gas supply scenarios have been applied in the experiments presented here. The first is the operation mode with a pulse injection of xenon into the interelectrode space, and the second is the operation mode with residual helium in the chamber and local injection of xenon directly into the compression zone. The maximum value of the electric current observed outside the MPC channel is 15 ÷ 20% of the total discharge current. Electric current vortices were discovered in the plasma stream. The amplitude of the current in the vortices reaches 50% of the total discharge current. The maximum EUV radiation power was measured in the mode of MPC operation with local xenon injection. Power in the wave range 12.2 ÷ 15.8 nm achieves up to 16 ÷ 18 kW

    Covariant Quantum Dynamical Semigroups: Unbounded generators

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    A survey of the probabilistic approaches to quantum dynamical semigroups with unbounded generators is given. An emphasis is made upon recent advances in the structural theory of covariant Markovian master equations. The relations with the classical Levy-Khinchin formula are elucidated. As an example, a complete characterizations of the Galilean covariant irreversible quantum Markovian evolutions is given in terms of the corresponding quantum master and Langevin equations. Important topics for future investigation are outlined.Comment: 14 pages,Latex, no figures, submitted to the Semigroup Volume, Group 21, Goslar 199

    УСТРАНЕНИЕ ДЕФЕКТОВ ОСНОВАНИЯ ЧЕРЕПА И СРЕДНЕЙ ЗОНЫ ЛИЦА ПОСЛЕ ХИРУРГИЧЕСКОГО ЛЕЧЕНИЯ РАСПРОСТРАНЕННЫХ КРАНИОМАКСИЛЛЯРНЫХ ОПУХОЛЕЙ

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    Introduction. Performance the radical surgical treatment in patients with widespread cranio-maxillary tumors is followed by appearance of extensive defects.Objective. To explore the possibility of the applying the basic methods of eliminating defects cranio-maxillary localization after surgical treatment of tumors and their impact on quality of life and survival.Material and methods. The results of surgical treatment of 94 patients with the widespread cranio-maxillary tumors, depending on the performed type of the surgery and method of eliminating postoperative defects were analyzed.Results. Efficiency of different methods of reconstruction of defects of the midface and anterior skull base and their impact on quality of life and survival after the surgery were estimated. The use of general oncological methods in combination with the methods of the primary effectively correction of formed defects allows to achieve better results in the treatment of patients with widespread cranio-maxillary tumors. .Введение. Выполнение радикального оперативного пособия у пациентов с распространенными краниомаксиллярными опухолями сопровождается возникновением обширных дефектов.Цель исследования – изучить возможности применения основных методик устранения дефектов краниомаксиллярной локализации после хирургического лечения опухолей, их влияние на качество жизни и выживаемость.Материал и методы. Проанализированы результаты хирургического лечения 94 больных с распространенными краниомаксиллярными опухолями в зависимости от характера выполненного оперативного вмешательства, применяемой методики устранения послеоперационных дефектов.Результаты. Выполнена оценка эффективности использования различных методов в реконструкции дефектов средней зоны лица и основания черепа после хирургического лечения, их влияния на качество жизни и выживаемость. Применение онкологических методик в сочетании с первичным устранением образовавшихся дефектов позволяет добиться более высоких результатов лечения краниомаксиллярных опухолей

    The wind regime of the mesosphere and lower thermosphere during the DYANA campaign-I. Prevailing winds

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    During the DYANA campaign, winds and tides at mesospheric and lower thermospheric altitudes were measured by 14 ground based experiments (MF radars, meteor radars and LF-drift systems). The experiments were located between 107°W and 102°E, mostly in northern mid-latitudes with well covered areas in Central and Eastern Europe. Emphasis is placed here upon the vertical profiles and height-time contours of the prevailing zonal and meridional winds with different resolution (15 d, 4d). Generally, westerly winds are observed at heights below 95 km with a strong mesospheric variability and with longitudinal differences between the data of Central Europe, Eastern Europe, Asia and Canada. Planetary waves and a minor stratospheric warming in the first 10 days of February 1990 are the cause of this behaviour. In connection with the stratospheric warming, a wind reversal to summer east winds reaching from the upper stratosphere up to 95 km is observed. The close connection of the behaviour of the stratosphere with the observed longitudinal differences in the mesospheric response on the stratospheric warming and with the occurrence of wind oscillations (10-15 d) is discussed. © 1994

    The wind regime of the mesosphere and lower thermosphere during the DYANA campaign-II. Semi-diurnal tide

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    Co-ordinated ground-based radar measurements carried out during the 15 January-15 March 1990 DYANA campaign at 14 different geographical sites have provided a good opportunity to investigate the characteristics of semi-diurnal tidal variations in the mesosphere/lower thermosphere over a wide spectrum of space/time scales. It is pointed out that significant differences of monthly mean tidal parameters observed at the various sites may be explained by latitudinal and longitudinal effects. Well-defined 2-3-week oscillations of the tidal parameters are found to be typical of all observational sites. Their estimated space scales do not contradict the hypothesis about a possible coupling between these oscillations and the low wave-number processes in the stratosphere. Tidal parameter oscillations with 2-5-day periods may be explained to be effects of the nonstationary processes with longitudinal wave numbers S > 3. © 1994

    Роль микроРНК в развитии радиорезистентности клеток рака предстательной железы (экспериментальное исследование)

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    Background. Radiation therapy is one of the leading treatments for early and late stage prostate cancer. Radiation therapy is one of the leading treatments for early and late stage prostate cancer. The significant frequency of prostate cancer progression after radiation therapy makes it relevant to study the molecular mechanisms of the development of radioresistance, to identify prognostic markers of its development.Objective: identification and analysis of the mechanism of action of microRNAs regulating radioresistance of prostate cancer cells on the model of the androgen-independent DU145 cell line.Materials and methods. We used human prostate adenocarcinoma cell lines: DU145-hormone-independent prostate cancer cell line and DU145-RR - its radioresistant variant. Differential microRNA expression was measured in cultured DU145 and DU145-RR cells 1, 8 days after a single gamma irradiation at a dose of 4 Gy. To analyze the differential expression of microRNAs in the initial and radioresistant variants of DU145 cells, the HiSeq 2000 platform (Illumina Inc., USA) was used. The miRBase v.21 database was used to identify microRNAs. The miRTarbase 7.0 and KEGG PATHWAY databases were used for bioinformatic analysisResults. The results of the study showed that the aberrant expression of miR-101-3p, -148a-3p, -21-3p, -532-5p, -92a-3p in DU145-RR cells upregulated compared to that in DU145 cells, and miR-125b-5p, -23a-3p, -424-3p - downregulated. It has been shown that the role of these microRNAs is associated with the provision of functional interaction between DNA methyltransferases, the transcriptional regulator of the proto-oncogenic protein Myc, and PTEN phosphatase in the regulation of the activity of MAPK and PI3K protein kinase signaling cascades. Constitutive activation of these cascades leads to an increase in cell survival, migration, proliferation, and growth.Conclusion. A wide range of target genes and a significant change in the expression profiles of microRNAs in various conditions, including the transition of malignant cells to a radioresistant status, makes microRNAs promising prognostic markers of radioresistance in prostate cancer.Введение. Лучевая терапия - один из ведущих методов лечения рака предстательной железы на ранней и поздней стадиях развития. Значительная частота прогрессирования рака предстательной железы после лучевой терапии делает актуальными изучение молекулярных механизмов развития радиорезистентности и выявление прогностических маркеров ее развития.Цель исследования - идентификация и анализ механизма действия микроРНК, регулирующих радиорезистентность клеток рака предстательной железы на модели андрогеннезависимой клеточной линии DU145.Материалы и методы. В работе использовали клеточные линии аденокарциномы предстательной железы человека: DU145 - гормононезависимую клеточную линию рака предстательной железы и DU145-RR - ее радиорезистент-ный вариант. Дифференциальную экспрессию микроРНК измеряли в культивируемых клетках DU145 и DU145-RR через 1 и 8 сут после однократного Y-облучения в дозе 4 Гр. Для анализа дифференциальной экспрессии микроРНК в исходном и радиорезистентном вариантах клеток DU145 использовали платформу HiSeq 2000 (Illumina Inc., США). Для идентификации микроРНК применяли базу данных miRBase v.21. Для биоинформатического анализа - базы данных miRTarbase 7.0 и KEGG PATHWAY.Результаты. Результаты исследования показали, что аберрантная экспрессия miR-101-3p, -148a-3p, -21-3p, -532-5p, -92a-3p в клетках DU145-RR повышается по сравнению с таковой в клетках DU145, а miR-125b-5p, -23a-3p, -424-3p -снижается. Показано, что роль этих микроРНК связана с обеспечением функционального взаимодействия между ДНК-метилтрансферазами, транскрипционным регулятором протоонкогенного белка Myc, а также фосфатазой PTEN в регуляции активности протеинкиназных сигнальных каскадов MAPK и PI3K. Конститутивная активация данных каскадов приводит к повышению выживаемости, миграции, пролиферации и росту клеток.Заключение. Широкий спектр генов-мишеней и существенное изменение профилей экспрессии микроРНК при различных состояниях, включая переход злокачественных клеток в радиорезистентный статус, делают микроРНК перспективными прогностическими маркерами радиорезистентности при раке предстательной железы

    Predicting Missing Links via Local Information

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    Missing link prediction of networks is of both theoretical interest and practical significance in modern science. In this paper, we empirically investigate a simple framework of link prediction on the basis of node similarity. We compare nine well-known local similarity measures on six real networks. The results indicate that the simplest measure, namely common neighbors, has the best overall performance, and the Adamic-Adar index performs the second best. A new similarity measure, motivated by the resource allocation process taking place on networks, is proposed and shown to have higher prediction accuracy than common neighbors. It is found that many links are assigned same scores if only the information of the nearest neighbors is used. We therefore design another new measure exploited information of the next nearest neighbors, which can remarkably enhance the prediction accuracy.Comment: For International Workshop: "The Physics Approach To Risk: Agent-Based Models and Networks", http://intern.sg.ethz.ch/cost-p10

    Characterization of the Row Geometric Mean Ranking with a Group Consensus Axiom

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    An axiomatic approach is applied to the problem of extracting a ranking of the alternatives from a pairwise comparison ratio matrix. The ordering induced by row geometric mean method is proved to be uniquely determined by three independent axioms, anonymity (independence of the labelling of alternatives), responsiveness (a kind of monotonicity property) and aggregation invariance, which requires the preservation of group consensus, that is, the pairwise ranking between two alternatives should remain unchanged if unanimous individual preferences are combined by geometric mean.Comment: 17 pages, 2 figure
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