Rendez-vous of dwarfs

We present observations of multiple system of dwarf galaxies at the Russian 6-m telescope and the GMRT (Giant Metrewave Radio Telescope). The optical observations are a part of the programme Study of Groups of Dwarf Galaxies in the Local Supercluster. The group of galaxies under consideration looks like filament of 5 dwarfs. Two faint galaxies show peculiar structure. Long slit spectrum reveals inner motions about 150 km/s in one of them. It suggests that the galaxy is on stage of ongoing interaction. Probably, we see the group in moment of its formation.Comment: 2 pages, 3 figures; to appear in the proceedings of the conference "A Universe of dwarf galaxies" (Lyon, June 14-18, 2010

Catalog of Nearby Isolated Galaxies in the Volume z<0.01

We present a catalog of 520 most isolated nearby galaxies with radial velocities V_LG<3500 km/s covering the entire sky. This population of "space orphans" makes up 4.8% among 10900 galaxies with measured radial velocities. We describe the isolation criterion used to select our sample, called the "Local Orphan Galaxies" (LOG), and discuss their basic optical and HI properties. A half of the LOG catalog is occupied by the Sdm, Im and Ir morphological type galaxies without a bulge. The median ratio M_gas/M_star in the LOG galaxies exceeds 1. The distribution of the catalog galaxies on the sky looks uniform with some signatures of a weak clustering on the scale of about 0.5 Mpc. The LOG galaxies are located in the regions where the mean local density of matter is approximately 50 times lower than the mean global density. We indicate a number of LOG galaxies with distorted structures, which may be the consequence of interaction of isolated galaxies with massive dark objects

Low-Density Structures in the Local Universe. II. Nearby Cosmic Voids

We present the results of the search for spherical volumes containing no galaxies with luminosities brighter than the Magellanic Clouds in the Local Supercluster and its vicinity. Within a distance of 40 Mpc from us, 89 cosmic voids were discovered with the diameters of 24 to 12 Mpc, containing no galaxies with absolute magnitudes brighter than M_K < -18.4. A list of these voids and the sky distribution maps are given. It was found that 93% of spherical voids overlap, forming three more extended percolated voids (hypervoids). The largest of them, HV1, has 56 initial spherical cells and extends in a horseshoe shape, enveloping the Local Volume and the Virgo cluster. The Local Void (Tully, 1988) in the Hercules-Aquila region is the closest part of the HV1. Another hypervoid, HV2, contains 22 spherical voids in the Eridanus constellation, and the third compact hypervoid (HV3) comprises 6 spherical cells in the Bootes. The total volume of these voids incorporates about 30% of the Local Universe. Among 2906 dwarf galaxies excluded from the original sample (n = 10502) in the search for spherical volumes, only 68 are located in the voids we have discovered. They are characterized by late morphological types (85% are Ir, Im, BCD, Sm), absolute magnitudes M_B ranging from -13.0 to -16.7, moderate star formation rates (log SSFR ~ -10 M_sun/(yr*L_sun) and gas reserves per luminosity unit twice to three times larger than in the other dwarf galaxies located in normal environments. The dwarf population of the voids shows a certain tendency to sit shallow near the surfaces of cosmic voids

DETECTION PRECURSORY ANOMALIES OF ZHUPANOVSKY EARTHQUAKE ON JANUARY 30, 2016 WITH MW = 7.2 AND A DEPTH OF FOCUS 171 KM (KAMCHATKA) BY EIGENOSCOPY METHOD

This paper describes application of the eigenoscopy technique for analyzing the collective behavior of soil radon time series in order to detect the precursory anomalies before the deep Zhupanovsky earthquake with M = 7.2. Eigenoscope (from English .eigenvector.) or analyzer of eigenvectors and signal components. is a virtual device that allows us to detect the reference points of collective behavior in multidimensional time series. The multidimensional time series (01.08.2015-17.02.2016), obtained at the network of subsoil radon monitoring stations of the Petropavlovsk-Kamchatsky geodynamic test area, are considered. Before the deep earthquake with M = 7.2, which occurred at a distance of 120 km from the registration point, a reference point in the dynamics of soil radon, which can be considered as a precursory anomaly, was confidently detected with the help of the eigenoscopy method

Comparative Analysis of the Paracrine Action of Neuronal and Glial Progenitor Cells Derived from Induced Human Pluripotent Stem Cells

We performed comparative analysis of paracrine activity of neuronal and glial progenitors derived from induced pluripotent stem cells under conditions of hypoxia modeled by addition of cobalt dichloride. Neuronal and glial progenitors produced neuroprotective and neurotrophic effects on SHSY-5Y neuroblastoma cells in co-culture during the post-hypoxic recovery and reduced the number of apoptotic and necrotic cells. Moreover, they produced a neurotrophic effect and promote the formation and growth of neurites in neuroblastoma cells. The paracrine effect of glial progenitors was more pronounced, which can be explained by more intensive expression and secretion of neurotrophic factors in these cells. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

Сравнительный анализ паракринного действия нейрональных и глиальных предшественников, полученных из индуцированных плюрипотентных стволовых клеток человека

The article is focused on comparative analysis of the in vitro paracrine activity shown by the induced pluripotent stem cell-derived neuronal and glial progenitors and directed towards SHSY-5Y neuroblastoma cells during the recovery from hypoxic stress modeled by the exposure to cobalt dichloride. Co-cultivation with neuronal and glial progenitors exerted neuroprotective and neurotrophic effects on SHSY-5Y cells during the post-hypoxic recovery, reducing the number of apoptotic and necrotic cells and supporting neurite outgrowth. Moreover, the paracrine effect of glial progenitors was more pronounced compared to neuronal progenitors, which may be explained by a higher level of expression and secretion of neurotrophic factors by glial progenitors.Проведён сравнительный анализ паракринной активности нейрональных и глиальных предшественников, полученных из индуцированных плюрипотентных стволовых клеток, при моделировании гипоксии добавлением дихлорида кобальта. Сокультивирование с нейрональными и глиальными предшественниками оказывало нейропротективное действие на клетки нейробластомы SHSY-5Y, снижая количество апоптотических и некротических клеток в культуре. Кроме того, сокультивирование обеспечивало нейротрофический эффект, способствуя нейритогенезу в клетках линии SHSY-5Y. При этом паракринное влияние глиальных предшественников было более выраженным, что может объясняться более высоким уровнем экспрессии нейротрофических факторов в данных клетках

Comparative impact analysis of neuronal and glial progenitors conditioned medium on cerebellar neurons under glutamate exitotoxicity

One of the main causes of cell death in neurodegenerative diseases is excitotoxicity. Today the potential directions of treatment neurodegenerative diseases are including cell therapy, the purpose of which is to replace lost nerve tissue with donor cells. Transplanted cells along with replaced lost tissues have a paracrine effect, which requires careful study. The aim of this work was to study the effect of conditioned media, obtaining from neuronal and glial progenitor cells, on a primary culture of cerebellar neurons in a model of glutamate excitotoxicity. The cell viability, expression of marker genes for apoptosis and neuritogenesis, and the number of necrotic and apoptotic cells were determined in the culture of cerebellar neurons. The composition of the studied conditioned media was analyzed for the content of neurotrophins. A comparative analysis was revealed differences in the secretion of neurotrophins between the obtained cultures: the amount of brain-derived neurotrophic factor, nerve growth factor, ciliary neurotrophic factor and glial neurotrophic factor was higher in the secretion of glial progenitors. It was shown that the addition of conditioned media from neuronal cells does not significantly affect the viability of cerebellar neurons, whereas preincubation with media from glial progenitors has a neuroprotective effect by increasing the viability of cerebellar neurons, and during long-term cultivation promotes the growth of neurites by increasing the expression level of MAP2 and GAP43 genes. © 2019, Human Stem Cell Institute. All rights reserved