CHROMOSOME REARRANGEMENTS AFTER LOW X-RAY DOSES GIVEN TO SPERMATOGONIA OF MICE

1968 ◽  
Vol 10 (1) ◽  
pp. 119-124 ◽  
Author(s):  
A. Léonard ◽  
Gh. Deknudt
Keyword(s):  
Regression Coefficient ◽  
Whole Body ◽  
X Rays ◽  
Male Mice ◽  
Drying Method ◽  
Air Drying ◽  
X Ray ◽  
Abnormal Cells ◽  
Low X ◽  
The Relationship

Male mice from the BALB/c strain were given whole-body irradiation at doses of 25, 50, 75 and 100 R of X-rays. Seventy days after irradiation the mice were killed, the testes removed and meiotic preparations were made using an air-drying method. Translocation configurations involving four chromosomes were the most frequent type recorded. The percentage of translocations increased regularly from 0.42 after 25 R to 1.96 after 100 R. The relationship between the X-ray dose and the rate of abnormal cells appears to be linear with a regression coefficient of b = 0.018960.

Preliminary Study on the Anti-radiation Effect of Jen-Sheng-Yang-Yung-Tang

1993 ◽  
Vol 21 (02) ◽  
pp. 187-195 ◽  
Author(s):  
Hsue-yin Hsu ◽  
Yau-hui Ho ◽  
Shi-Iong Lian ◽  
Chun-ching Lin
Keyword(s):  
Bone Marrow ◽  
Radiation Effect ◽  
Bone Marrow Cells ◽  
X Rays ◽  
Male Mice ◽  
X Ray ◽  
Colony Forming Units ◽  
Before And After ◽  
Preliminary Study ◽  
Different Doses

Six to seven week old male mice of ICR strain were exposed to different doses of x-rays to determine if Jen-Sheng-Yang-Yung-Tang could be a modifier in the elimination of radiation damage. Colony forming units of bone marrow cells in the spleen (CFUs) were measured before and after x-ray irradiation with intraperitoneal injection of 10 mg/20 g or 20 mg/20 g body weight of Jen-Sheng-Yang-Yung-Tang, once a day for seven consecutive days. The recovery of CFUs and hemocytes counts by 4 Gy irradiation with Jen-Sheng-Yang-Yung-Tang administration was faster for a concentration of 20 mg/20 g than 10 mg/20 g. The measurement of 10-day CFUs showed an increase of radiotolerance in the treatment of 20 mg/20 g administration before x-ray irradiation. The injection of Jen-Sheng-Yang-Yung-Tang accelerated the recovery of hemocyte counts in mice irradiated with 4 Gy x-ray; the effect was especially profound for leukocytes with 20 mg/20 g Jen-Sheng-Yang-Yung-Tang administration after irradiation.

scholarly journals X-ray spectra and light curves of cooling novae and a nova like

2020 ◽  
Vol 499 (2) ◽  
pp. 3006-3018
Author(s):  
Bangzheng Sun ◽  
Marina Orio ◽  
Andrej Dobrotka ◽  
Gerardo Juan Manuel Luna ◽  
Sergey Shugarov ◽  
...  
Keyword(s):  
Light Curve ◽  
Accretion Rate ◽  
High Energy ◽  
Gravitational Energy ◽  
Light Curves ◽  
Clear Correlation ◽  
X Rays ◽  
High State ◽  
X Ray ◽  
Low X

ABSTRACT We present X-ray observations of novae V2491 Cyg and KT Eri about 9 yr post-outburst of the dwarf nova and post-nova candidate EY Cyg, and of a VY Scl variable. The first three objects were observed with XMM–Newton, KT Eri also with the Chandra ACIS-S camera, V794 Aql with the Chandra ACIS-S camera and High Energy Transmission Gratings. The two recent novae, similar in outburst amplitude and light curve, appear very different at quiescence. Assuming half of the gravitational energy is irradiated in X-rays, V2491 Cyg is accreting at $\dot{m}=1.4\times 10^{-9}{\!-\!}10^{-8}\,{\rm M}_\odot \,{\rm yr}^{-1}$, while for KT Eri, $\dot{m}\lt 2\times 10^{-10}{\rm M}_\odot \,{\rm yr}$. V2491 Cyg shows signatures of a magnetized WD, specifically of an intermediate polar. A periodicity of  39 min, detected in outburst, was still measured and is likely due to WD rotation. EY Cyg is accreting at $\dot{m}\sim 1.8\times 10^{-11}{\rm M}_\odot \,{\rm yr}^{-1}$, one magnitude lower than KT Eri, consistently with its U Gem outburst behaviour and its quiescent UV flux. The X-rays are modulated with the orbital period, despite the system’s low inclination, probably due to the X-ray flux of the secondary. A period of  81 min is also detected, suggesting that it may also be an intermediate polar. V794 Aql had low X-ray luminosity during an optically high state, about the same level as in a recent optically low state. Thus, we find no clear correlation between optical and X-ray luminosity: the accretion rate seems unstable and variable. The very hard X-ray spectrum indicates a massive WD.

scholarly journals Magnetic fields, winds and X-rays of massive stars in the Orion nebula cluster

2010 ◽  
Vol 6 (S272) ◽  
pp. 208-209 ◽  
Author(s):  
Véronique Petit ◽  
Gregg A. Wade ◽  
Evelyne Alecian ◽  
Laurent Drissen ◽  
Thierry Montmerle ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Massive Stars ◽  
Theoretical Models ◽  
Magnetic Star ◽  
X Rays ◽  
Orion Nebula ◽  
X Ray ◽  
Ob Stars ◽  
The Impact ◽  
The Relationship

AbstractIn some massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind. Although theoretical models and MHD simulations are able to illustrate the dynamics of such a magnetized wind, the impact of this wind-field interaction on the observable properties of a magnetic star - X-ray emission, photometric and spectral variability - is still unclear. The aim of this study is to examine the relationship between magnetism, stellar winds and X-ray emission of OB stars, by providing empirical observations and confronting theory. In conjunction with the COUP survey of the Orion Nebula Cluster, we carried out spectropolarimatric ESPaDOnS observations to determine the magnetic properties of massive OB stars of this cluster.

Probing the spatial coherence of wide X-ray beams with Fresnel mirrors at BL25SU of SPring-8

2019 ◽  
Vol 26 (3) ◽  
pp. 756-761
Author(s):  
Yoko Takeo ◽  
Hiroto Motoyama ◽  
Yasunori Senba ◽  
Hikaru Kishimoto ◽  
Haruhiko Ohashi ◽  
...  
Keyword(s):  
Optical System ◽  
Spatial Coherence ◽  
Optical Systems ◽  
X Rays ◽  
X Ray ◽  
Interference Fringes ◽  
Radiation Sources ◽  
Wide Wavelength Range ◽  
Valuable Method ◽  
The Relationship

Probing the spatial coherence of X-rays has become increasingly important when designing advanced optical systems for beamlines at synchrotron radiation sources and free-electron lasers. Double-slit experiments at various slit widths are a typical method of quantitatively measuring the spatial coherence over a wide wavelength range including the X-ray region. However, this method cannot be used for the analysis of spatial coherence when the two evaluation points are separated by a large distance of the order of millimetres owing to the extremely narrow spacing between the interference fringes. A Fresnel-mirror-based optical system can produce interference patterns by crossing two beams from two small mirrors separated in the transverse direction to the X-ray beam. The fringe spacing can be controlled via the incidence angles on the mirrors. In this study, a Fresnel-mirror-based optical system was constructed at the soft X-ray beamline (BL25SU) of SPring-8. The relationship between the coherence and size of the virtual source was quantitatively measured at 300 eV in both the vertical and horizontal directions using the beam. The results obtained indicate that this is a valuable method for the optimization of optical systems along beamlines.

scholarly journals Magnetic fields, winds and X-rays of massive stars in the Orion Nebula Cluster

2008 ◽  
Vol 4 (S259) ◽  
pp. 449-452 ◽  
Author(s):  
Véronique Petit ◽  
G. A. Wade ◽  
L. Drissen ◽  
T. Montmerle ◽  
E. Alecian
Keyword(s):  
Magnetic Fields ◽  
Massive Stars ◽  
Magnetic Confinement ◽  
Stellar Winds ◽  
X Rays ◽  
Orion Nebula ◽  
X Ray ◽  
Ob Stars ◽  
Complex Processes ◽  
The Relationship

AbstractIn massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind, resulting in X-ray emission that is harder, more variable and more efficient than that produced by instability-generated shocks in non-magnetic winds. Although magnetic confinement of stellar winds has been shown to strongly modify the mass-loss and X-ray characteristics of massive OB stars, we lack a detailed understanding of the complex processes responsible. The aim of this study is to examine the relationship between magnetism, stellar winds and X-ray emission of OB stars. In conjunction with a Chandra survey of the Orion Nebula Cluster, we carried out spectropolarimatric ESPaDOnS observations to determine the magnetic properties of massive OB stars of this cluster.

scholarly journals Historical Supernovae and Supernova Remnants

1996 ◽  
Vol 145 ◽  
pp. 323-331 ◽  
Author(s):  
Zhenru Wang
Keyword(s):  
Tang Dynasty ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
High Energy ◽  
X Rays ◽  
Supernovae And Supernova Remnants ◽  
X Ray ◽  
The Tang Dynasty ◽  
High Energy Emission ◽  
The Relationship

The oldest historical supernova (SN), recorded by ancient Chinese in 14th Century B.C. on pieces of tortoise shells or bones, is identified with the aid of modern space γ-ray observations. Hard X-rays with energy up to 20 keV were observed from IC 443 by the X-ray satellite Ginga. We infer from these observations the age of IC 443 is ∼ 1000 — 1400 yrs. The result supports the hypothesis that IC 443 is the remnant of the historical SN 837 that occurred during the Tang Dynasty. The association between the supernova remnant (SNR) CTB 80 and SN 1408 has been hotly debated for about ten years and is briefly reviewed and discussed here. A new picture is presented to explain this association. High energy emission from historical SNRs can persist in a multiphase interstellar medium (ISM). As a result, the study of the relationship between SNRs and ancient guest stars has gained new vitality.

Formation of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 257-264
Author(s):  
D Lynden-Bell
Keyword(s):  
Angular Momentum ◽  
Binding Energy ◽  
Kinetic Energy ◽  
Gravitational Potential Energy ◽  
Dimensionless Number ◽  
X Rays ◽  
X Ray ◽  
The Galaxy ◽  
Balmer Lines ◽  
The Relationship

From observations it is deduced that the disk and halo were formed about the same time and that most of the previously gaseous Galaxy became stars then. Dimensional analysis indicates that the flattening of a galaxy is related to its energy,E, angular momentum,H, and mass,M, by the dimensionless number - 2EH2/G5M5. Emphasis is placed on the binding energy, -E, and the energy loss mechanisms of the proto-galaxy, with the aim of explaining Fish's relation -E∝M3/2.Free-bound and free-free emission of hydrogen leads to rapid cooling of proto-galaxies, and dynamical collapse ensues, in which gravitational potential energy is converted into kinetic energy of collapse. As the system becomes flat, this energy is dissipated in violent shocks, behind which zones some 10 to 20 pc thick reach temperatures of 106·5°K and emit strongly in the X-ray region and the ultraviolet. If surrounded by more than a fraction of a gram per cm2, the X-rays will be trapped within the system and eventually converted into Balmer lines, which escape, and Lyman α, which is trapped. About half the total energy of collapse may be left in Lyman α, and it is possible that the system may bounce on this light energy.The readily observed surface brightnesses of galaxies are related to surface densities by the relationship: magnitude 20 per (sec of arc)2= 1·5 gram cm-2, for an assumed mass-to-light ratio of 10.

Cerium Oxide Nanoparticles Reduce X-ray Irradiation-Induced Damage to the Immune Cells by Upregulation of Superoxide Dismutase and Glutathione Peroxidase

2019 ◽  
Vol 11 (10) ◽  
pp. 1464-1469
Author(s):  
Shaoyan Si ◽  
Lindong Li ◽  
Zongye Wang ◽  
Yingying Wu ◽  
Gaixian Shan ◽  
...  
Keyword(s):  
T Cells ◽  
Superoxide Dismutase ◽  
Ionizing Radiation ◽  
Glutathione Peroxidase ◽  
Immune Function ◽  
Cerium Oxide ◽  
Immune Cells ◽  
Whole Body ◽  
X Rays ◽  
X Ray

Ionizing radiation cause serious damage to humans by inducing reactive oxygen species (ROS). Immune system is one of the most sensitive system to ionizing radiation. Cerium oxide (CeO2) nanoparticles are strong ROS scavengers. In this research we observed that whether CeO2 nanoparticles could improve immune function of X-rays irradiated mice and their antioxidant potential. The whole body of mice were once exposed to 4 Gy X-ray and treated with 5 nm CeO2 nanoparticles. Then, immune cells distribution in peripheral blood (PB), spleen T cells proliferation, spleen and thymus indexes, the concentration of Glutathione Peroxidase (GSH-Px) and the activity of Superoxide Dismutase (SOD) were analyzed. The results showed that CeO2 nanoparticles could inprove immune cells distribution in PB and increase spleen T cells proliferation, thymus and spleen indexes, concentration of GSH-Px and activity of SOD in irradiated mice. The results suggest that CeO2 nanoparticles can improve immune function by inducing the production of GSH-Px and SOD in X-ray irradiated mice.

Resistance to whole-body X-irradiation in rats made tolerant to bacterial endotoxins

1959 ◽  
Vol 197 (6) ◽  
pp. 1364-1370 ◽  
Author(s):  
B. W. Zweifach ◽  
E. Kivy-Rosenberg ◽  
Arnold L. Nagler
Keyword(s):  
Blood Platelet ◽  
Reticuloendothelial System ◽  
Whole Body ◽  
X Rays ◽  
Effective Protection ◽  
X Ray ◽  
E Coli ◽  
Bacterial Endotoxins ◽  
X Irradiation ◽  
Reticulo Endothelial System

Rats were treated with three conditioning agents (bacterial endotoxins, zymosan and compound 48/80) known to produce tolerance to other forms of stress, as a means of determining the importance of the reticulo-endothelial system in the response to WBR. Effective protection was provided by tolerance induced by lipopolysaccharide extracts of E. coli bacteria. Some protection was also afforded by conditioning with 48/80 for several days. These agents were active only when administered before exposure to x-rays. Treatment post x-ray broke down the induced resistance. Blood platelet levels remained high in conditioned animals exposed to WBR. It is suggested that a relationship exists between the priming or conditioning of the reticuloendothelial system and the maintenance of satisfactory blood platelet levels in adapted animals receiving WBR.

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