NGC 7468: a galaxy with an inner polar disk

We present our spectroscopic observations of the galaxy NGC 7468 performed at the 6-m Special Astrophysical Observatory telescope using the UAGS long-slit spectrograph, the multipupil fiber spectrograph MPFS, and the scanning Fabry-Perot interferometer (IFP). We found no significant deviations from the circular rotation of the galactic disk in the velocity field in the regions of brightness excess along the major axis of the galaxy (the putative polar ring). Thus, these features are either tidal structures or weakly developed spiral arms. However, we detected a gaseous disk at the center of the galaxy whose rotation plane is almost perpendicular to the plane of the galactic disk. The central collision of NGC 7468 with a gas-rich dwarf galaxy and their subsequent merging seem to be responsible for the formation of this disk.Comment: 8 pages, 6 figures, accepted in Astronomy Letters, 2004, vol 30., N 9, p. 58

Inner Polar Rings and Disks: Observed Properties

A list of galaxies with inner regions revealing polar (or strongly inclined to the main galactic plane) disks and rings is compiled from the literature data. The list contains 47 galaxies of all morphological types, from E to Irr. We consider the statistics of the parameters of polar structures known from observations. The radii of the majority of them do not exceed 1.5 kpc. The polar structures are equally common in barred and unbarred galaxies. At the same time, if a galaxy has a bar (or a triaxial bulge), this leads to the polar disk stabilization - its axis of rotation usually coincides with the major axis of the bar. More than two thirds of all considered galaxies reveal one or another sign of recent interaction or merging. This fact indicates a direct relation between the external environment and the presence of an inner polar structure.Comment: 12 pages, 3 figures, accepted to Astrophysical Bulletin. Minor changes and corrections are still possibl

Beta herpes viruses in patients with cutaneous graft-versus-host disease

Graft-versus-host disease is a major complication of allogenic bone marrow transplantation. Beta herpes viruses’ role in pathogenesis and prognosis of graft-versus-host disease is significant. Objective: To study beta herpes viruses evidence in skin biopsy specimens in graft-versus-host disease patients. Material and methods: Clinical features of 50 patients with cutaneous graft-versus-host disease were examined. Cytomegalovirus and human herpes virus 6 DNA detection in skin biopsy specimens was performed by PCR. Results: Correlation between human herpes virus 6 and poor prognosis in graft-versus-host disease patients has been found. Conclusion: Beta herpes virus detection after allogenic bone marrow transplantation could be important in prognosis of graft-versus-host disease

Dark Matter Search Perspectives with GAMMA-400

GAMMA-400 is a future high-energy gamma-ray telescope, designed to measure the fluxes of gamma-rays and cosmic-ray electrons + positrons, which can be produced by annihilation or decay of dark matter particles, and to survey the celestial sphere in order to study point and extended sources of gamma-rays, measure energy spectra of Galactic and extragalactic diffuse gamma-ray emission, gamma-ray bursts, and gamma-ray emission from the Sun. GAMMA-400 covers the energy range from 100 MeV to ~3000 GeV. Its angular resolution is ~0.01 deg(Eg > 100 GeV), and the energy resolution ~1% (Eg > 10 GeV). GAMMA-400 is planned to be launched on the Russian space platform Navigator in 2019. The GAMMA-400 perspectives in the search for dark matter in various scenarios are presented in this paperComment: 4 pages, 4 figures, submitted to the Proceedings of the International Cosmic-Ray Conference 2013, Brazil, Rio de Janeir

Оценка размерных показателей элементов проводящего рисунка печатных плат, полученных с помощью 3D-печати

Introduction. A review of foreign publications on 3D printing methods shows the possibility of their application for the manufacture of printed circuit boards (PCBs), while demonstrating the growth of interest in this field. One of the available methods is fused deposition modeling, which can be used to form substrates with channels for traces. At present, the minimum channel width comprises 100 µm, which corresponds to the 5th class of PCB accuracy. However, there is no data on how to obtain such dimensions or on the magnitude of their deviation from the given nominal values.Aim. To determine the influence of such factors as nozzle diameter and the number of contours on the dimensional characteristics of PCBs (linear dimensions; trace channel width; trace spacing; via diameters).Materials and methods. To obtain linear models, a full factorial experiment was carried out. The influence of the following materials was evaluated – polylactide (PLA), acrylonitrile butadiene styrene (ABS) and glass-filled ABS; slicers – Ultimaker Cura and PrusaSlicer; 3D printers – Picaso 3D Designer Classic 2016 and Hercules Strong 2017; brass nozzle with diameters ∅0.2 and ∅0.4 mm. The possibility of using brass nozzles coated with chemical nickel for printing with glass-filled filaments was considered. The study was conducted using the facilities of the "Center for Additive Technologies" of Bauman Moscow State Technical University.Results. The possibility of manufacturing PCBs up to the 2nd and 3rd accuracy classes using nozzles with a diameter of ∅0.4 and ∅0.2 mm, respectively, was shown. It was found that galvanic deposition of chemical nickel on a ∅0.2 mm brass nozzle makes it possible to increase the PCB wearability when printing with glass-filled filaments. Recommendations are proposed for selecting an optimal combination of nozzle diameter and the number of contours.Conclusion. The conducted analysis of mathematical models shows the significance of such parameters as nozzle diameter and the number of contours. The results can be used when creating new PCB layoutsВведение. Анализ зарубежных исследовательских работ, посвященных методам 3D-печати, показывает возможность их применения для изготовления печатных плат (ПП), а также демонстрирует рост интереса в данном направлении. Одним из доступных методов является метод послойного наложения филамента, который обычно применяется для формирования подложки с каналами под проводники. На текущий момент минимальная ширина канала составляет 100 мкм, что соответствует 5-му классу точности ПП. Однако данные о способе получения подобных размеров или об уровне их отклонения от заданных номинальных значений отсутствуют.Цель работы. Определить влияние таких производственно-технологических факторов, как диаметр экструзионного сопла (ЭС) и количество контуров, на размерные характеристики ПП (линейные размеры, ширина канала печатного проводника, расстояние между проводниками, диаметр сквозного отверстия).Материалы и методы. Для получения линейных моделей проводится полный факторный эксперимент. Оценивается влияние материалов – полилактид (PLA), акрилонитрил бутадиен стирол (ABS) и стеклонаполненный ABS; слайсеров – Ultimaker Cura и PrusaSlicer; 3D-принтеров – Picaso 3D Designer Classic 2016 и Hercules Strong 2017; латунных ЭС диаметрами ∅0.2 и ∅0.4 мм. Рассматривается возможность применения латунных ЭС, покрытых химическим никелем, для печати стеклонаполненными филаментами. Исследование проводилось на производственной базе Научно-образовательного центра "Центр аддитивных технологий" при МГТУ им. Н. Э. Баумана.Результаты. Показана возможность изготовления ПП до 2-го класса точности при использовании ЭС ∅ 0.4 мм и до 3-го класса точности для ЭС ∅0.2 мм. Выявлено, что гальваническое нанесение химического никеля на латунное ЭС ∅0.2 мм позволяет повысить его износостойкость для печати стеклонаполненными филаментами. Даны рекомендации по выбору комбинации диаметра ЭС и количества контуров.Заключение. Анализ полученных адекватных математических моделей показывает значимость диаметра ЭС и количества контуров. Полученные результаты могут быть использованы для создания макетов П