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Bai Z.-J.,Beijing University of Technology | Fu X.-M.,Chinese National Institute for Radiological Protection | Jiao C.-F.,University of North Carolina at Chapel Hill | Xu F.-R.,Beijing University of Technology
Chinese Physics C | Year: 2015

Total Routhian Surface (TRS) calculations have been performed to investigate shape coexistence and evolution in neutron-deficient krypton isotopes 72,74,76Kr. The ground-state shape is found to change from oblate in 72Kr to prolate in 74,76Kr, in agreement with experimental data. Quadrupole deformations of the ground states and coexisting 0+2 states as well as excitation energies of the latter are also well reproduced. While the general agreement between calculated moments of inertia and those deduced from observed spectra confirms the prolate nature of the low-lying yrast states of all three isotopes (except the ground state of 72Kr), the deviation at low spins suggests significant shape mixing. The role of triaxiality in describing shape coexistence and evolution in these nuclei is finally discussed. © 2015 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd. Source


Yu Z.,Harvard University | Liu N.,Harvard University | Liu J.,Chinese National Institute for Radiological Protection | Yang K.,Harvard University | Wang X.,Harvard University
International Journal of Molecular Sciences | Year: 2012

Brain neurons and tissues respond to sublethal injury by activating endogenous protective pathways. Recently, following the failure of a large number of clinical trials for protective strategies against stroke that aim to inhibit a specific ischemia response pathway, endogenous neuroprotection has emerged as a more promising and hopeful strategy for development of therapeutics against stroke and neurodegenerative disorders. Neuroglobin (Ngb) is an oxygen-binding globin protein that is highly and specifically expressed in brain neurons. Accumulating evidence have clearly demonstrated that Ngb is an endogenous neuroprotective molecule against hypoxic/ischemic and oxidative stress-related insults in cultured neurons and animals, as well as neurodegenerative disorders such as Alzheimer's disease, thus any pharmacological strategy that can up-regulate endogenous Ngb expression may lead to novel therapeutics against these brain disorders. In this review, we summarize recent studies about the biological function, regulation of gene expression, and neuroprotective mechanisms of Ngb. Furthermore, strategies for identification of chemical compounds that can up-regulate endogenous Ngb expression for neuroprotection against stroke and neurodegenerative disorders are discussed. © 2012 by the authors; licensee MDPI, Basel, Switzerland. Source


Luo J.,Hexi University | Luo J.,Lanzhou University | Tuo F.,Chinese National Institute for Radiological Protection | Kong X.,Lanzhou University
Journal of Radioanalytical and Nuclear Chemistry | Year: 2011

The cross sections for formation of metastable state of 178Hf (178m2Hf, 574.215 keV, 31 y) and 179Hf ( 179m2Hf, 362.55 keV, 25.05 d) through reactions induced by 14.8 ± 0.2 MeV neutrons on natural hafnium were measured for the first time. The monoenergetic neutron beam was produced via the 3H(d, n) 4He reaction on ZF-300-II Intense Neutron Generator at Lanzhou University. Induced gamma activities were measured by a gamma-ray spectrometer with high-purity germanium (HPGe) detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The neutron fluence were determined by the cross section of 93Nb(n, 2n)92mNb reaction. The neutron energy in the measurement were by the cross section ratios of 90Zr(n, 2n) 89m+gZr and 93Nb(n, 2n)92mNb reactions. © 2011 Akadémiai Kiadó, Budapest, Hungary. Source


Zhao Y.,Beijing Normal University | Yan D.,Beijing Normal University | Zhang Q.,Beijing Normal University | Zhang Q.,Chinese National Institute for Radiological Protection | And 2 more authors.
Journal of Environmental Radioactivity | Year: 2012

Artificial Radiocaesium ( 137Cs) has been widely deposited over global soils. In this study, we measured 137Cs activity concentrations in the soil samples taken from Jing-Jin-Ji Region, North China, during 2007-2008. The surface soil (0-20cm) samples were collected from 452 sites in this region. The activity concentration of 137Cs in the samples was measured using a GEM series HPGe (high-purity germanium) coaxial detector system (ADCOM-100). The main findings are as following. (1) The activity concentration of 137Cs in surface soils in the region of study fluctuates within 0.3±0.1 to 12.9±0.4Bq/kg with mean value of 3.7Bq/kg. Compared to other regions located at roughly the same latitude, the 137Cs activity is relatively low. The results indicate that there are no new inputs of the radionuclides into the area at that time and the data obtained could serve as baseline levels of 137Cs in Jing-Jin-Ji Region. (2) Considering land use types, surface soil in woodland mostly shows high 137Cs activities with rare natural erosion and anthropogenic activities, and the surface soil with relatively low 137Cs activities appears in the areas of intensive anthropogenic activities, especially in the cities, river banks, reservoirs and the strongly eroded areas. The findings suggest that the varying distribution of 137Cs activities in surface soil corresponds with land use types. © 2012 Elsevier Ltd. Source


Wang X.-C.,Chinese Academy of Sciences | Tian L.-L.,Centers for Disease Control and Prevention | Tian J.,Cancer Prevention and Treatment Institute of Shandong Province | Jiang X.-Y.,Chinese National Institute for Radiological Protection
Radiation Research | Year: 2012

SKP2 is the substrate recognition subunit of the SCF SKP2 ubiquitin ligase complex. It is implicated in ubiquitin-mediated degradation of the cyclin-dependent kinase (CDK) inhibitor p27 KIP1 and positively regulates the G1/S transition. Overexpression of SKP2 has been found in many kinds of tumors. In the present study, we found that SKP2 expression levels increased in esophageal squamous cell carcinoma tissues. Elevated expression of SKP2 correlated significantly with tumor stage and positive lymph node metastasis (P < 0.05). Moreover, a significantly negative correlation was found between SKP2 expression and the survival of patients who received radiotherapy (P < 0.05). At the molecular level, induced expression of SKP2 promoted the radioresistance of EC9706 cells. Knockdown of SKP2 expression sensitized cancer cells to radiation, and a wobble mutant of SKP2 that was resistant to SKP2 siRNA was able to rescue this effect. Increased or decreased expression levels of SKP2 had effects on Rad51 expression after irradiation. These results demonstrate for the first time that overexpression of SKP2 was correlated with the increased radioresistance of esophageal squamous cell carcinoma. Elevated expression of SKP2 promoted the radioresistance of cancer cells, and this effect was mediated at least in part by the Rad51 pathway. © 2012 by Radiation Research Society. Source

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