Clustered DNA damage is considered as a critical type of lesions induced by ionizing radiation, which can be converted into the fatal or strong mutagenic complex double strand breaks (DSBs) during damage processing in...Clustered DNA damage is considered as a critical type of lesions induced by ionizing radiation, which can be converted into the fatal or strong mutagenic complex double strand breaks (DSBs) during damage processing in the cells. The new data show that high energy protons produce more potentially lethal DSBs than low LET radiation. In this study, plasmid DNA were used to in-vestigate and re-evaluate the biological effects induced by the protons with the LET of ～3.6 keV/μm at the molecular level in vitro, including single strand breaks (SSBs), DSBs, isolated and clustered base damages. The results of complex DNA damage detections indicated that protons at the given LET value induce about 1.6 fold more non-DSB clustered DNA damages than the prompt DSB. The DNA damage yields by protons were greater than that by γ-rays, specifically by 6 fold for the isolated type of DNA damage and 14 fold for the clustered damage. Furthermore, the spectrum of damages was also demonstrated to be depended on the radiation quality, with protons producing more DSBs relative to clusters than do γ-rays.展开更多
The 3 P F2 superfluidity of neutron and proton is investigated in isospin-asymmetric nuclear matter within the Brueckner-Hartree-Fock approach and the BCS theory by adopting the Argonne V14 and the Argonne V18 nucleon...The 3 P F2 superfluidity of neutron and proton is investigated in isospin-asymmetric nuclear matter within the Brueckner-Hartree-Fock approach and the BCS theory by adopting the Argonne V14 and the Argonne V18 nucleonnucleon interactions. We find that pairing gaps in the 3PF2 channel predicted by adopting the AV14 interaction are much larger than those by the AV18 interaction. As the isospin-asymmetry increases, the neutron 3 pF2 superfluidity is found to increase rapidly, whereas the proton one turns out to decrease and may even vanish at high enough asymmetries. As a consequence, the neutron 3pF2 superfluidity is much stronger than the proton one at high asymmetries and it predominates over the proton one in dense neutron-rich matter.展开更多
Effect of isospin dependence of nucleon-nucieon cross sectionσNNiso on the neutron-proton ratio of nucleon emissions (n/p)free as the increase of neutron-proton ratio of collision system (n/p)sys is investigated in h...Effect of isospin dependence of nucleon-nucieon cross sectionσNNiso on the neutron-proton ratio of nucleon emissions (n/p)free as the increase of neutron-proton ratio of collision system (n/p)sys is investigated in heavy ion collisions. Where the isospin independent N-N cross sectionσ1noiso andσ2noiso are defined asσnn=σpp =σnp(σ1noiso) andσnn=σpp= (1/2)(σnp+σnn) (σ2noiso) respectively. Because the isospin dependent in-medium N-N cross sectionσNNiso,especially the neutron-proton to proton-proton (neutron-neutron) cross section展开更多
As we know that the density distribution is more extended and the binding energy is decreased as the increase of neutron-proton ratio of neutron-halo nuclei,i. e. ,the inner structure of neutron-halo nuclei is more lo...As we know that the density distribution is more extended and the binding energy is decreased as the increase of neutron-proton ratio of neutron-halo nuclei,i. e. ,the inner structure of neutron-halo nuclei is more loose with increasing neutron-proton ratio of neutron-halo nuclei. In this way, it should be a close relationship between the fragmentation violence of neutron-halo projectile and the inner structure of neutronhalo nuclei in heavy ion Collisions. The fragmentation violence of neutron-halo projectile is indicated by展开更多
We studied the effect of isospin dependent momentum interaction(IDMI) on the isospin fractionation ratio and its dynamical mechanism by using the quantum molecular dynamics model in intermediate energy heavy ion colli...We studied the effect of isospin dependent momentum interaction(IDMI) on the isospin fractionation ratio and its dynamical mechanism by using the quantum molecular dynamics model in intermediate energy heavy ion collisions. Fig.1 shows the (N/Z)nucl/(N/Z)frag at freeze-out time as a function of the neutron-proton ratio of colliding system with MDI and IDMI for the reactions 94Kr+94Kr,94Zr+94Zr, 94Mo+94Mo and 94Ru+94Ru at a beam energy of 50 MeV/u and an impact parameter of 2.0 fm. There are the same mass 188 for展开更多
基金supported by the National Science Foundation for Distinguished Young Scholars of China (30825011)the National Natural Science Foundation of China (10805078)
文摘Clustered DNA damage is considered as a critical type of lesions induced by ionizing radiation, which can be converted into the fatal or strong mutagenic complex double strand breaks (DSBs) during damage processing in the cells. The new data show that high energy protons produce more potentially lethal DSBs than low LET radiation. In this study, plasmid DNA were used to in-vestigate and re-evaluate the biological effects induced by the protons with the LET of ～3.6 keV/μm at the molecular level in vitro, including single strand breaks (SSBs), DSBs, isolated and clustered base damages. The results of complex DNA damage detections indicated that protons at the given LET value induce about 1.6 fold more non-DSB clustered DNA damages than the prompt DSB. The DNA damage yields by protons were greater than that by γ-rays, specifically by 6 fold for the isolated type of DNA damage and 14 fold for the clustered damage. Furthermore, the spectrum of damages was also demonstrated to be depended on the radiation quality, with protons producing more DSBs relative to clusters than do γ-rays.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10575119, 10875151, 10811130077, and 10811130560the Knowledge Innovation Project (KJCX3-SYW-N2) of the Chinese Academy of Sciences+2 种基金the Major State Basic Research Developing Program of China under Grant No. 2007CB815004the CAS/SAFEA International Partnership Program for Creative Research Teams(CXTD-J2005-1) of Chinese Academy of Sciencesthe Asia-Link project (CN/ASIA-LINK/008(94791)) of the European Commission
文摘The 3 P F2 superfluidity of neutron and proton is investigated in isospin-asymmetric nuclear matter within the Brueckner-Hartree-Fock approach and the BCS theory by adopting the Argonne V14 and the Argonne V18 nucleonnucleon interactions. We find that pairing gaps in the 3PF2 channel predicted by adopting the AV14 interaction are much larger than those by the AV18 interaction. As the isospin-asymmetry increases, the neutron 3 pF2 superfluidity is found to increase rapidly, whereas the proton one turns out to decrease and may even vanish at high enough asymmetries. As a consequence, the neutron 3pF2 superfluidity is much stronger than the proton one at high asymmetries and it predominates over the proton one in dense neutron-rich matter.
文摘Effect of isospin dependence of nucleon-nucieon cross sectionσNNiso on the neutron-proton ratio of nucleon emissions (n/p)free as the increase of neutron-proton ratio of collision system (n/p)sys is investigated in heavy ion collisions. Where the isospin independent N-N cross sectionσ1noiso andσ2noiso are defined asσnn=σpp =σnp(σ1noiso) andσnn=σpp= (1/2)(σnp+σnn) (σ2noiso) respectively. Because the isospin dependent in-medium N-N cross sectionσNNiso,especially the neutron-proton to proton-proton (neutron-neutron) cross section
文摘As we know that the density distribution is more extended and the binding energy is decreased as the increase of neutron-proton ratio of neutron-halo nuclei,i. e. ,the inner structure of neutron-halo nuclei is more loose with increasing neutron-proton ratio of neutron-halo nuclei. In this way, it should be a close relationship between the fragmentation violence of neutron-halo projectile and the inner structure of neutronhalo nuclei in heavy ion Collisions. The fragmentation violence of neutron-halo projectile is indicated by
文摘We studied the effect of isospin dependent momentum interaction(IDMI) on the isospin fractionation ratio and its dynamical mechanism by using the quantum molecular dynamics model in intermediate energy heavy ion collisions. Fig.1 shows the (N/Z)nucl/(N/Z)frag at freeze-out time as a function of the neutron-proton ratio of colliding system with MDI and IDMI for the reactions 94Kr+94Kr,94Zr+94Zr, 94Mo+94Mo and 94Ru+94Ru at a beam energy of 50 MeV/u and an impact parameter of 2.0 fm. There are the same mass 188 for
