Neutrino Signal from a Population of Seyfert Galaxies.

IceCube Collaboration has previously reported evidence for a neutrino signal from a Seyfert galaxy NGC 1068. This may suggest that all Seyfert galaxies emit neutrinos. To test this hypothesis, we identify the best candidate neutrino sources among nearby Seyfert galaxies, based on their hard x-ray properties. Only two other sources, NGC 4151 and NGC 3079 are expected to be detectable in 10 years of IceCube data. We find evidence (∼3σ) for a neutrino signal from both sources in a publicly available ten-year IceCube dataset. Though neither source alone is above the threshold for discovery, the chance coincidence probability to find the observed neutrino count excesses in the directions of the two out of two expected sources, in addition to the previously reported brightest source, is p<2.6×10^{-7}. This corresponds to a correlation between Seyfert galaxies and neutrino emission.

Signatures of a Two Million Year Old Supernova in the Spectra of Cosmic Ray Protons, Antiprotons, and Positrons.

The locally observed cosmic ray spectrum has several puzzling features, such as the excess of positrons and antiprotons above ~20 GeV and the discrepancy in the slopes of the spectra of cosmic ray protons and heavier nuclei in the TeV-PeV energy range. We show that these features are consistently explained by a nearby source which was active approximately two million years ago and has injected (2-3)×10^{50} erg in cosmic rays. The transient nature of the source and its overall energy budget point to the supernova origin of this local cosmic ray source. The age of the supernova suggests that the local cosmic ray injection was produced by the same supernova that has deposited ^{60}Fe isotopes in the deep ocean crust.

Low-energy break in the spectrum of Galactic cosmic rays.

Measurements of the low-energy spectrum of Galactic cosmic rays (GCRs) by detectors on or near Earth are affected by solar modulation. To overcome this difficulty, we consider nearby molecular clouds as GCR detectors outside the Solar System. Using γ-ray observations of the clouds by the Fermi telescope, we derive the spectrum of GCRs in the clouds from the observed γ-ray emission spectrum. We find that the GCR spectrum has a low-energy break with the spectral slope hardening by ΔΓ=1.1±0.3 at an energy of E=9±3 GeV. Detection of a low-energy break enables a measurement of GCR energy density in the interstellar space U=0.9±0.3 eV/cm{3}.

Universal properties of dark matter halos.

We discuss the universal relation between density and size of observed dark matter halos that was recently shown to hold on a wide range of scales, from dwarf galaxies to galaxy clusters. Predictions of cold dark matter (ΛCDM) N-body simulations are consistent with this relation. We demonstrate that this property of ΛCDM can be understood analytically in the secondary infall model. Qualitative understanding given by this model provides a new way to predict which deviations from ΛCDM or large-scale modifications of gravity can affect universal behavior and, therefore, to constrain them observationally.

Limbal explants from cryopreserved cadaver human corneas. Immunofluorescence and light microscopy of epithelial cells growing in culture.

The aim of the present study was to determine whether human cadaver corneas, that were subject to cryopreservation, would be a source of migrating epithelial cells in vitro and what kind of morphological features these cells possess. Limbal explant culture was used for expanding the epithelial cells. Non-quantitative light microscopical examinations of the cultures within a period of 28 days were carried out. The phenotype of cultured cells, particularly of the presumed adult stem cell population, was examined by indirect fluorescent immunostaining using antibodies against corneal stem cell associated markers p63 and vimentin. The effectiveness of the freezing-thawing protocol was confirmed by cultivation of limbal explants taken from non-cryopreserved cadaver corneoscleral rims. The result clearly showed that limbal tissue, subjected to cryopreservation and long lasting (up to 12 months) storage in liquid nitrogen, retains the capacity to be source of migrating and proliferating epithelial cells in vitro including the presumed adult stem cells and transient amplifying cells.

Strategy for searching for a dark matter sterile neutrino.

We propose a strategy for how to look for dark matter particles possessing a radiative decay channel and derive constraints on their parameters from observations of x rays from our own Galaxy and its dwarf satellites. When applied to sterile neutrinos in the keV mass range this approach gives a significant improvement to restrictions on neutrino parameters compared with previous works.

Quantum cosmology of the brane universe.

We canonically quantize the dynamics of the brane universe embedded into the five-dimensional Schwarzschild-anti-de Sitter bulk space-time. We show that in the brane-world settings the formulation of the quantum cosmology, including the problem of initial conditions, is conceptually more simple than in the (3+1)-dimensional case. The Wheeler-DeWitt equation is a finite-difference equation. It is exactly solvable in the case of a flat universe and we find the ground state of the system. The closed brane universe can be created as a result of decay of the bulk black hole.

Integrity of endothelium in cryopreserved human cornea.

The aim of the present study was to elaborate an optimal method for cryopreservation of human donor cornea for transplantation and to follow the morphological changes in the structure of the endothelial cell layer using scanning electron microscopy (SEM). Sixteen groups, with four donor cornea each, were cryopreserved at cooling rates of 1 degree C per min and 5 degree C per min. Four cryoprotectants (glycerol, dimethyl sulfoxide, 1,2-propanediol, polyethylene glycol-400) in two concentrations (5% and 10% v/v) were prepared on the bases of medium Optisol GS supplied with 20% v/v human serum albumin. Four additional human cornea were used as controls. Endothelial cell recovery of the cornea after thawing and 24 hours culture, was calculated as a percent of the preserved recovered cells. Sufficient recovery of the endothelial cell layer, making the cornea suitable for transplantation was obtained using the cryoprotectants dimethyl sulfoxide and especially polyethylene glycol-400.

Large-scale extragalactic jets powered by very-high-energy gamma rays.

The radiative cooling of electrons responsible for the nonthermal synchrotron emission of large-scale jets of radiogalaxies and quasars requires quasicontinuous (in time and space) production of relativistic electrons throughout the jets over the scales exceeding 100 kpc. While in the standard paradigm of large-scale jets this implies in situ acceleration of electrons, we propose a different "nonacceleration" origin of these electrons, assuming that they are implemented all over the length of the jet through effective development of electromagnetic cascades initiated by extremely high-energy gamma rays injected into the jet from the central object.

[Tailed. New options in therapy of bronchial asthma]. / Tailed. Novye vozmozhnosti terapii bronchial'noi astmy.

Patients with mild and moderate bacterial bronchial asthma received tailed in a dose 8 mg/day for 15 days. Positive changes were registered in bronchial permeability, hemodynamics in the lesser circulation. Hydrocortisone and immune unbalance was corrected.

Interleukin production by human colostral cells after in vitro mitogen stimulation.

Human colostral cells were pulsed with PHA, Con A, or LPS and cultivated in serum-free medium. The culture supernatants were tested for IL-1 activity in C3H/HeJ thymocyte assay and for IL-2 activity on human lymphoblasts. The IL-1 activity was the highest at the 24th h of cultivation and IL-2 activity at the 48th h of cultivation.

Relationship between the effect of cyclophosphamide on adjuvant arthritis severity, skin allograft rejection and spleen cell cytotoxic activity in rats.

Cyclophosphamide, which has a poor immunosuppressive effect on adjuvant arthritis in rats, evokes an aggravating form of the disease when applied at a single low dose before rats' sensitization with complete Freund's adjuvant. However, cyclophosphamide administered by this method of treatment has no such enhancement effect on skin allograft rejection reaction; on the contrary, the rejection reaction was inhibited. Spleen cell cytotoxic activity against 51-Cr labelled chondrocytes significantly decreased in adjuvant arthritis, while in skin allograft rejection it increased during the latent period before the rejection reaction appeared. The addition of cyclophosphamide to the rats' treatment decreased more strongly spleen cell cytotoxic activity, especially in rats with adjuvant arthritis. We conclude that cyclophosphamide-sensitive spleen cytotoxic cells are playing a dual role in the pathogenesis of these two cell-mediated immunological processes: as immunosuppressive regulatory cells in adjuvant arthritis and as effector cells in skin allograft rejection reaction.