2007 Vol. 24, No. 2
Proceedings of the 3rd Biophysics Workshop
Display Method:
2007, 24(2): 85-88.
doi: 10.11804/NuclPhysRev.24.02.085
Abstract:
The new progresses on heavyion cancer therapy and treatment facilities in Institute of Modern Physics (IMP), Chinese Academy of Sciences, are introduced, and the development program of heavyion cancer therapy is presented.
The new progresses on heavyion cancer therapy and treatment facilities in Institute of Modern Physics (IMP), Chinese Academy of Sciences, are introduced, and the development program of heavyion cancer therapy is presented.
2007, 24(2): 89-93.
doi: 10.11804/NuclPhysRev.24.02.089
Abstract:
The depthsurvival effect of a βdelayed particle decay 9C beam on human salivary gland (HSG) cells is presented in this paper. Compared with a stable 12Cion beam， the radioactive 9Cion beam showed an enhanced biological effect， i.e.， remarkably enhanced efficiency in cell killing， at the penetration depths around its Bragg peak. The biophysical mechanisms underlying the enhanced biological effect are discussed herein， and the latest progress in biological effect induced by another radioactive 8Bion beam is introduced. In the end of this paper， several topics concerning the frontier of the radiationinduced biological effects using radioactive ion beams are proposed.
The depthsurvival effect of a βdelayed particle decay 9C beam on human salivary gland (HSG) cells is presented in this paper. Compared with a stable 12Cion beam， the radioactive 9Cion beam showed an enhanced biological effect， i.e.， remarkably enhanced efficiency in cell killing， at the penetration depths around its Bragg peak. The biophysical mechanisms underlying the enhanced biological effect are discussed herein， and the latest progress in biological effect induced by another radioactive 8Bion beam is introduced. In the end of this paper， several topics concerning the frontier of the radiationinduced biological effects using radioactive ion beams are proposed.
2007, 24(2): 94-97.
doi: 10.11804/NuclPhysRev.24.02.094
Abstract:
The several theoretical models of cell inactivation or cell survival fraction are introduced. Emphasis is placed on a new model——Ionization Ionization Clustering Cluster model. In order to understand some of the mechanisms of DNA damage related to cell killing and their dependence on radiation quality, the yields of single track lethal events are compared with the estimated yields of different classes of complex DNA lesions calculated by a fast Monte Carlo methods.
The several theoretical models of cell inactivation or cell survival fraction are introduced. Emphasis is placed on a new model——Ionization Ionization Clustering Cluster model. In order to understand some of the mechanisms of DNA damage related to cell killing and their dependence on radiation quality, the yields of single track lethal events are compared with the estimated yields of different classes of complex DNA lesions calculated by a fast Monte Carlo methods.
2007, 24(2): 98-102.
doi: 10.11804/NuclPhysRev.24.02.098
Abstract:
The potential energy surface of the H13 proton in base cytosine of the
DNA molecules is calculated ab initio at the Gaussian98 MP2/6311G(d， p) level. Two potential wells are found. One corre sponds to the normal cytosine， while the other corresponds to its imino tautomer. The bindings of the proton in these wells are stable enough against the thermodisturbance. The motions of the proton in these wells are oscillations around the nearest nitrogen atom like the pendulum， and may move far away from the nitrogen atom to form the hydrogen bond with other bases. The estimated tunneling
probability of the H13 proton from one well to another well shows that the life time of the proton staying in one of these wells is about 6×102 a. It is too long to let tautomers of cytosine be in thermodynamical equilibrium in a room temperature gas phase experiment. The biological significance of these results is discussed.
The potential energy surface of the H13 proton in base cytosine of the
DNA molecules is calculated ab initio at the Gaussian98 MP2/6311G(d， p) level. Two potential wells are found. One corre sponds to the normal cytosine， while the other corresponds to its imino tautomer. The bindings of the proton in these wells are stable enough against the thermodisturbance. The motions of the proton in these wells are oscillations around the nearest nitrogen atom like the pendulum， and may move far away from the nitrogen atom to form the hydrogen bond with other bases. The estimated tunneling
probability of the H13 proton from one well to another well shows that the life time of the proton staying in one of these wells is about 6×102 a. It is too long to let tautomers of cytosine be in thermodynamical equilibrium in a room temperature gas phase experiment. The biological significance of these results is discussed.
2007, 24(2): 103-107.
doi: 10.11804/NuclPhysRev.24.02.103
Abstract:
As two factors， the changes of concentration of DNA and dose rate are of significance in the study of DNA damage induced by irradiation. The influence of DNA damage induced by γ ray at different concentration of DNA under different dose rate was investigated. The result of gel electrophoresis indicate that DNA molecules were damaged severely as the concentration of DNA decreasing. The number of double strand breakages per DNA were obtained by the software of Alpha Innotech and theoretical analysis. It shows that the numbers of double strand breakages per DNA presented nonlinear feature as the concentration of DNA decreasing, and the dose rate had little influence on DNA damage.
As two factors， the changes of concentration of DNA and dose rate are of significance in the study of DNA damage induced by irradiation. The influence of DNA damage induced by γ ray at different concentration of DNA under different dose rate was investigated. The result of gel electrophoresis indicate that DNA molecules were damaged severely as the concentration of DNA decreasing. The number of double strand breakages per DNA were obtained by the software of Alpha Innotech and theoretical analysis. It shows that the numbers of double strand breakages per DNA presented nonlinear feature as the concentration of DNA decreasing, and the dose rate had little influence on DNA damage.
2007, 24(2): 108-111.
doi: 10.11804/NuclPhysRev.24.02.108
Abstract:
Space radiation come from galactic cosmic rays and solar particle events which contain considerable protons is an invisible killer to astronauts. Furthermore， many wounded persons were injured by proton and other heavy ion radiation in a nuclear warhead or nuclear terrorism attack. However， the damage effect of proton radiation is known little in our country. In this study， the proton induced histopathologic changes of mice were observed primarily. naesthetic mice were irradiated with the 19 MeV protons dili vered by HI13 tandem accelerator at CIAE in different doses(2， 4， 8， 16 Gy). In order to observe the da mage effect， mice were killed by anaesthetic at different time point after radiation， and the tissue sections were analyzed by a histopathologic method. The results show that all of the mice’s backs began displaying ringed depilation at postirradiation day 7. Many epidermal cells necrosis and exfoliation happened， and subcutaneous dropsy was observed. There were some focal necrosis or even followed with bleeding in heart and liver. Hepatocyte evidently regenerated. A hyperaemia was seen in lung tissue and alveolar septum was obviously thickening. Acinus renis represented notable pyknosis， necrosis and disappearance. Especially， these pathologic alteration clearly displayed in high dose groups. In conclusion， protonradiation can induce different grade injury to skin， heart， liver， lung， kidney and other organs. Further studies should be made to deeply understand the mechanism about the proton radiation damage.
Space radiation come from galactic cosmic rays and solar particle events which contain considerable protons is an invisible killer to astronauts. Furthermore， many wounded persons were injured by proton and other heavy ion radiation in a nuclear warhead or nuclear terrorism attack. However， the damage effect of proton radiation is known little in our country. In this study， the proton induced histopathologic changes of mice were observed primarily. naesthetic mice were irradiated with the 19 MeV protons dili vered by HI13 tandem accelerator at CIAE in different doses(2， 4， 8， 16 Gy). In order to observe the da mage effect， mice were killed by anaesthetic at different time point after radiation， and the tissue sections were analyzed by a histopathologic method. The results show that all of the mice’s backs began displaying ringed depilation at postirradiation day 7. Many epidermal cells necrosis and exfoliation happened， and subcutaneous dropsy was observed. There were some focal necrosis or even followed with bleeding in heart and liver. Hepatocyte evidently regenerated. A hyperaemia was seen in lung tissue and alveolar septum was obviously thickening. Acinus renis represented notable pyknosis， necrosis and disappearance. Especially， these pathologic alteration clearly displayed in high dose groups. In conclusion， protonradiation can induce different grade injury to skin， heart， liver， lung， kidney and other organs. Further studies should be made to deeply understand the mechanism about the proton radiation damage.
2007, 24(2): 112-116.
doi: 10.11804/NuclPhysRev.24.02.112
Abstract:
To determine whether lowdose preirradiation could enhance adenovirusmediated p53 transfer and expression in human prostate adenocarcinoma， the PC3 cells were preexposed to γ rays， and then infected with replicationdeficient adenovirus recombinant vectors， containing human wildtype p53 (AdCMVp53) or green fluorescent protein gene (AdCMVGFP) respectively (γray irradiation + AdCMVp53 /GFP infection). The exogenous gene transfer and expression were detected by flow cytometric analysis. The GFP transfer frequencies in γ irradiation + AdCMVGFP infection groups were 7%—39% more than those in AdCMVGFP infection groups. The p53 levels in the γ irradiation + AdCMVp53 infection groups were 18.5%—35.4% more than those in AdCMVp53 infection groups (p<0.05)，suggesting that lowdose (less than or equal to 1.0 Gy) irradiation could significantly promote exogenous p53 transfer and expression in the PC3 cells. The survival fractions for the γ irradiation + AdCMVp53 infection groups were 25%—64%， 22%—65% less than those for AdCMVp53 infection， or γirradiation groups， respectively (p<0.05).
To determine whether lowdose preirradiation could enhance adenovirusmediated p53 transfer and expression in human prostate adenocarcinoma， the PC3 cells were preexposed to γ rays， and then infected with replicationdeficient adenovirus recombinant vectors， containing human wildtype p53 (AdCMVp53) or green fluorescent protein gene (AdCMVGFP) respectively (γray irradiation + AdCMVp53 /GFP infection). The exogenous gene transfer and expression were detected by flow cytometric analysis. The GFP transfer frequencies in γ irradiation + AdCMVGFP infection groups were 7%—39% more than those in AdCMVGFP infection groups. The p53 levels in the γ irradiation + AdCMVp53 infection groups were 18.5%—35.4% more than those in AdCMVp53 infection groups (p<0.05)，suggesting that lowdose (less than or equal to 1.0 Gy) irradiation could significantly promote exogenous p53 transfer and expression in the PC3 cells. The survival fractions for the γ irradiation + AdCMVp53 infection groups were 25%—64%， 22%—65% less than those for AdCMVp53 infection， or γirradiation groups， respectively (p<0.05).
2007, 24(2): 117-123.
doi: 10.11804/NuclPhysRev.24.02.117
Abstract:
As a new mutagenesis technique, low energy heavy ion implantation started in China for the study of interaction effect between incident ions and organism, and great achievements have been obtained in crop breeding. The article reviewed the main biological effects induced by heavy ion implantation, including physiology, biochemistry and genetics effects, on levels of cell and chromosome, gene expression, DNA methylation, DNA damage and reparation etc. It compared the differences in mutagenesis for organism by high energy and low energy ion implantation, as well as γ ray radiaiton. Future investigation topics were proposed, the emphasis of researches in future was pointed out, i.e., the molecular mechanism and effects of gene differential expression of organism treated by ion implantation.
As a new mutagenesis technique, low energy heavy ion implantation started in China for the study of interaction effect between incident ions and organism, and great achievements have been obtained in crop breeding. The article reviewed the main biological effects induced by heavy ion implantation, including physiology, biochemistry and genetics effects, on levels of cell and chromosome, gene expression, DNA methylation, DNA damage and reparation etc. It compared the differences in mutagenesis for organism by high energy and low energy ion implantation, as well as γ ray radiaiton. Future investigation topics were proposed, the emphasis of researches in future was pointed out, i.e., the molecular mechanism and effects of gene differential expression of organism treated by ion implantation.
2007, 24(2): 124-128.
doi: 10.11804/NuclPhysRev.24.02.124
Abstract:
In the present study， the autotetraploid rice IR364X was treated with ion implantation technique by nitrogen ion beams and a polyembryonic seedling mutant(named as the IR36Shuang) was identified in M2 generation. The mutant line was systematically investigated about the location of seedling in polyembryonic seedling, and the cytological initiation of the additional embryo in the IR36Shuang was observed and determined. The results are as follows: The location of seedling in the polyembryonic rice IR36Shuang could be differentiated into 2 types: the uncomplete twin seedlings and the complete twin seedlings. There were 2 types in the uncomplete twin seedlings， i.e. the twin seedlings with single plumule axis and single radicle and the twin seedlings with single radicle and twin plumule axis. The complete twin seedlings also included 2 types， i.e. the normal twin seedlings and the abnormal twin seedlings. The doubleembryo was observed during different embryo development stage of the IR36Shuang. The additional embryo in the IR36Shuang might arise from the double set of embryo sacs in single ovary， multi eggcell egg apparatus， antipodal cells or endosperm cells. The results revealed the practicability of ion beam implantation technique in creating new polyploidy idioplasm， which could provide a new approach for searching the material with apomixis.
In the present study， the autotetraploid rice IR364X was treated with ion implantation technique by nitrogen ion beams and a polyembryonic seedling mutant(named as the IR36Shuang) was identified in M2 generation. The mutant line was systematically investigated about the location of seedling in polyembryonic seedling, and the cytological initiation of the additional embryo in the IR36Shuang was observed and determined. The results are as follows: The location of seedling in the polyembryonic rice IR36Shuang could be differentiated into 2 types: the uncomplete twin seedlings and the complete twin seedlings. There were 2 types in the uncomplete twin seedlings， i.e. the twin seedlings with single plumule axis and single radicle and the twin seedlings with single radicle and twin plumule axis. The complete twin seedlings also included 2 types， i.e. the normal twin seedlings and the abnormal twin seedlings. The doubleembryo was observed during different embryo development stage of the IR36Shuang. The additional embryo in the IR36Shuang might arise from the double set of embryo sacs in single ovary， multi eggcell egg apparatus， antipodal cells or endosperm cells. The results revealed the practicability of ion beam implantation technique in creating new polyploidy idioplasm， which could provide a new approach for searching the material with apomixis.
2007, 24(2): 129-132.
doi: 10.11804/NuclPhysRev.24.02.129
Abstract:
The dry and watersaturated seeds of Arabidopsis thaliana were irradiated by H+ions with 6.5 MeV in atmosphere. The ion fluence used in this experiment was in the range of 4×109 —1×1014 ions/cm2. According to the structure of the seed and TRIM simulation， the ions with the energy of 6.5 MeV can penetrate the whole seed. The experiment shows that the fluenceresponse curves for the dry seeds and watersaturated seeds had distinct shoulders and reduced rapidly. The experimental results show that the waterimbibed seeds were more sensitive than the dry seeds and the reason is from free radicals reaction. A model has been constructed, and primely simulates the experiment data.
The dry and watersaturated seeds of Arabidopsis thaliana were irradiated by H+ions with 6.5 MeV in atmosphere. The ion fluence used in this experiment was in the range of 4×109 —1×1014 ions/cm2. According to the structure of the seed and TRIM simulation， the ions with the energy of 6.5 MeV can penetrate the whole seed. The experiment shows that the fluenceresponse curves for the dry seeds and watersaturated seeds had distinct shoulders and reduced rapidly. The experimental results show that the waterimbibed seeds were more sensitive than the dry seeds and the reason is from free radicals reaction. A model has been constructed, and primely simulates the experiment data.
2007, 24(2): 133-137.
doi: 10.11804/NuclPhysRev.24.02.133
Abstract:
In order to study the energy loss and its straggling of MeV energy ions in biological samples, onion membrane samples with different thickness were irradiated with 1.0, 1.8, 2.8 MeV H+ and 4.5 MeV He+ , respectively. The energy loss and straggling of these ions after penetrating the biological samples were measured with transmission energy spectrum. The experimental results show that the energy losses of MeV energy ions in the biological samples mentioned above are consistent with TRIM simulation but their energy straggling are different from the simulations. Considering the inhomogeneous mass density and structure of biological materials, we modified Bohr’s energy straggling theory, and then the results are in good agreemen with the experimental energy straggling values.
In order to study the energy loss and its straggling of MeV energy ions in biological samples, onion membrane samples with different thickness were irradiated with 1.0, 1.8, 2.8 MeV H+ and 4.5 MeV He+ , respectively. The energy loss and straggling of these ions after penetrating the biological samples were measured with transmission energy spectrum. The experimental results show that the energy losses of MeV energy ions in the biological samples mentioned above are consistent with TRIM simulation but their energy straggling are different from the simulations. Considering the inhomogeneous mass density and structure of biological materials, we modified Bohr’s energy straggling theory, and then the results are in good agreemen with the experimental energy straggling values.
2007, 24(2): 138-141.
doi: 10.11804/NuclPhysRev.24.02.138
Abstract:
The mechanisms of energy loss in the process of heavy ion interaction with biomolecule are analyzed and discussed， the recent related research progresses are reviewed and some future research directions are indicated.
The mechanisms of energy loss in the process of heavy ion interaction with biomolecule are analyzed and discussed， the recent related research progresses are reviewed and some future research directions are indicated.
2007, 24(2): 142-146.
doi: 10.11804/NuclPhysRev.24.02.142
Abstract:
Based on the Eigen model with a single peak fitness landscape， the fitness values of all sequence types are assumed to be random with Gaussian distribution. By ensemble average method， the concentration distribution and error threshold of quasispecies on single peak Gaussian distributed fitness landscapes were evaluated. It is shown that the concentration distribution and error threshold change little in comparing with deterministic case for small fluctuations， which implies that the error threshold is stable against small perturbation. However， as the fluctuation increases， the situation is quite different. The transition from quasispecies to error catastrophe is no longer sharp. The error threshold becomes a narrow band which broadens and shifts toward large values of error rate with increasing fluctuation.
Based on the Eigen model with a single peak fitness landscape， the fitness values of all sequence types are assumed to be random with Gaussian distribution. By ensemble average method， the concentration distribution and error threshold of quasispecies on single peak Gaussian distributed fitness landscapes were evaluated. It is shown that the concentration distribution and error threshold change little in comparing with deterministic case for small fluctuations， which implies that the error threshold is stable against small perturbation. However， as the fluctuation increases， the situation is quite different. The transition from quasispecies to error catastrophe is no longer sharp. The error threshold becomes a narrow band which broadens and shifts toward large values of error rate with increasing fluctuation.
2007, 24(2): 147-150.
doi: 10.11804/NuclPhysRev.24.02.147
Abstract:
157 cases of gastrointestinal cancer patients after resection were randomly divided into treated group and control group. The treated group (intraperitoneal hyperthermic perfusion chemotherapy combined with postoperative continuous intraarterial infusion and intravenous micropump chemotherapy) consisted of 72 cases， the control group (Intravenous chemotherapy)， 85 cases. The peritoneal and hepatic metastasis rates and 3 a survival rate were studied. The intraperitoneal hyperthermic perfusion chemotherapy combined with the postoperative continuous intraarterial infusion and intravenous micropump chemotherapy is an effective way to control the recurrence on the peritoneal and hepatic metastasis of advanced gastrointestinal neoplasms after operation.
157 cases of gastrointestinal cancer patients after resection were randomly divided into treated group and control group. The treated group (intraperitoneal hyperthermic perfusion chemotherapy combined with postoperative continuous intraarterial infusion and intravenous micropump chemotherapy) consisted of 72 cases， the control group (Intravenous chemotherapy)， 85 cases. The peritoneal and hepatic metastasis rates and 3 a survival rate were studied. The intraperitoneal hyperthermic perfusion chemotherapy combined with the postoperative continuous intraarterial infusion and intravenous micropump chemotherapy is an effective way to control the recurrence on the peritoneal and hepatic metastasis of advanced gastrointestinal neoplasms after operation.
2007, 24(2): 151-155.
doi: 10.11804/NuclPhysRev.24.02.151
Abstract:
The current status of nuclear power development and the actinides and some Long Lived Fission Products (LLFPs) in nuclear power spent fuel have been introduced. The radiation effect of spent fuel on biological circle in the viewpoint of Biological Hazard Potential (BHP) and Annual Limit of Intake were evaluated. The Accelerator Driven Subcritical System （ADS） as a strategy to transmute Minor Actinides (MAs) and LLFPs was recommended in order to reduce or eliminate the radiation effect of spent fuel on biological circle.
The current status of nuclear power development and the actinides and some Long Lived Fission Products (LLFPs) in nuclear power spent fuel have been introduced. The radiation effect of spent fuel on biological circle in the viewpoint of Biological Hazard Potential (BHP) and Annual Limit of Intake were evaluated. The Accelerator Driven Subcritical System （ADS） as a strategy to transmute Minor Actinides (MAs) and LLFPs was recommended in order to reduce or eliminate the radiation effect of spent fuel on biological circle.
2007, 24(2): 156-159.
doi: 10.11804/NuclPhysRev.24.02.156
Abstract:
Atomic structures and stabilities of Ni nanowires are studied by using the generalized simulated annealing method with SuttonChen potential. The initial structure is facecentered cubic [111] structure. The result shows that the length of the supercell strongly affects the structures and stabilities of Ni nanowires. fcc [111] structure， (6， 0)， (6， 3) nanowires， fcc[110]， transition structure and defect structure are found for different wire lengths. And from the analyses of the binding energy， it is found that (6， 0) nanowires (helical structure) is the most stable form.
Atomic structures and stabilities of Ni nanowires are studied by using the generalized simulated annealing method with SuttonChen potential. The initial structure is facecentered cubic [111] structure. The result shows that the length of the supercell strongly affects the structures and stabilities of Ni nanowires. fcc [111] structure， (6， 0)， (6， 3) nanowires， fcc[110]， transition structure and defect structure are found for different wire lengths. And from the analyses of the binding energy， it is found that (6， 0) nanowires (helical structure) is the most stable form.
2007, 24(2): 160-163.
doi: 10.11804/NuclPhysRev.24.02.160
Abstract:
A semiemperical molecular dynamics model was developed. The central collisions of C60 +C60 and Ar@C60 +Ar@C60 at the same incident energy were investigated within this model. The fullerene dimers could be formed by a selfassembly of C60 fullerene， and the new fullerene structure like “peanut” could be formed by a selfassembly of Ar@C60 . It was found that atom Ar had a great effect on the collision of Ar@C60 +Ar@C60 .
A semiemperical molecular dynamics model was developed. The central collisions of C60 +C60 and Ar@C60 +Ar@C60 at the same incident energy were investigated within this model. The fullerene dimers could be formed by a selfassembly of C60 fullerene， and the new fullerene structure like “peanut” could be formed by a selfassembly of Ar@C60 . It was found that atom Ar had a great effect on the collision of Ar@C60 +Ar@C60 .
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