以12个东北粳稻(Oryza sativa subsp.japonica)品种为研究对象,探究碳离子束辐照处理后不同水稻品种的辐照敏感性差异以及差异较大品种间苗期生理指标的区别。实验结果表明碳离子束(0、80、160Gy,80 Me V·u^(-1))对不同水稻品种的...以12个东北粳稻(Oryza sativa subsp.japonica)品种为研究对象,探究碳离子束辐照处理后不同水稻品种的辐照敏感性差异以及差异较大品种间苗期生理指标的区别。实验结果表明碳离子束(0、80、160Gy,80 Me V·u^(-1))对不同水稻品种的萌发产生了不同程度的影响,其中辐照对‘通禾66’萌发影响最小,而对‘吉粳809’萌发影响最大。进一步研究表明,碳离子束辐照对‘吉粳809’根和芽的生长抑制作用更明显,此外,其H_(2)O_(2)、超氧阴离子(O_(2)^(-)·)和丙二醛(MDA)含量均明显高于‘通禾66’,而抗氧化酶活性及非酶抗氧化物含量低于‘通禾66’。综上所述,与‘通禾66’相比,‘吉粳809’对碳离子束辐照更敏感,而抗氧化系统在二者辐照敏感性差异中起着重要作用。展开更多
The use of carbon-ion radiotherapy(CIRT)is gradually increasing.Owing to the generation of high-energy secondary neutrons during CIRT,its use presents new challenges in radiation protection.Thus,secondary neutron dose...The use of carbon-ion radiotherapy(CIRT)is gradually increasing.Owing to the generation of high-energy secondary neutrons during CIRT,its use presents new challenges in radiation protection.Thus,secondary neutron dose distributions must be explored and evaluated under clinical scenarios based on different treatment configurations.However,neutron dose and energy spectrum measurements are often difficult.This can be primarily attributed to the inherent limitations of most neutron detectors,such as their unsuitability for spectral measurements and inaccurate responses to neutrons with energies above 20 MeV.Numerical calculation methods based on probabilistic statistical theory are fast and convenient for neutron dose evaluation.In this study,external secondary neutron doses at the heavy ion medical machine in Wuwei,which is equipped with a passive beam delivery system,were calculated using the Monte Carlo method.The dependence of neutron doses on various treatment parameters(incident carbon-ion beam energy,spatial location,field size,and spread-out Bragg peak(SOBP)width)was investigated.Furthermore,the feasibility of applying an analytical model to predict the ambient dose equivalent was verified.For the combination involving an energy of 400 MeV=u and SOBP width of 6 cm,the ambient dose equivalent per therapeutic dose(H=D)at the isocenter was 79.87 mSv=Gy:The H=D value decreased rapidly with increasing spatial distance and slightly with increasing aperture size and SOBP width.The H=D values derived from the Monte Carlo simulations were in good agreement with the results reported in the literature.The analytical model could be used to quickly predict the H=D value along the incidence direction of the beam with an error of less than 20%.Thus,our study contributes to the understanding of the relationship between neutron radiation and treatment configuration parameters,which establishes a basis for predicting non-therapeutic radiation doses in CIRT.展开更多
Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years,but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found.In this study,a color-leaf mutant wit...Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years,but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found.In this study,a color-leaf mutant with purple leaves,stems and petals was isolated from clones of Wandering Jew irradiated by 95.8 MeV/u carbon ion beam.The concentration and histological distribution of leaf pigment were surveyed in wild type and mutant.In mutant,contents of total chlorophylls (Chl),chlorophyll a (Chl a),chlorophyll b (Chl b) and carotenoids (Car) decreased significantly,while concentration of the anthocyanins was 6.2-fold higher than that of wild type.Further composition analysis of anthocyanins by electrospray ionization mass spectrometry (ESI-MS) indicated that the purple pigmentation of leaves in mutant was caused by accumulation of petunidin anthocyanin.Microscopic examination showed that most petunidin anthocyanin accumulated in the lower epidermis,and little in vascular parenchyma of mutant,while there was no pigment in wild type.Meanwhile,in spongy parenchyma of mutant we observed little Chl,which the wild type abounds in.In conclusion,the color-leaf mutant of Wandering Jew induced by irradiation of carbon ions was improved in ornamental value,and it could be contribute to variation in level,component and distribution of foliar pigment.The possible mutation mechanisms were discussed.展开更多
文摘以12个东北粳稻(Oryza sativa subsp.japonica)品种为研究对象,探究碳离子束辐照处理后不同水稻品种的辐照敏感性差异以及差异较大品种间苗期生理指标的区别。实验结果表明碳离子束(0、80、160Gy,80 Me V·u^(-1))对不同水稻品种的萌发产生了不同程度的影响,其中辐照对‘通禾66’萌发影响最小,而对‘吉粳809’萌发影响最大。进一步研究表明,碳离子束辐照对‘吉粳809’根和芽的生长抑制作用更明显,此外,其H_(2)O_(2)、超氧阴离子(O_(2)^(-)·)和丙二醛(MDA)含量均明显高于‘通禾66’,而抗氧化酶活性及非酶抗氧化物含量低于‘通禾66’。综上所述,与‘通禾66’相比,‘吉粳809’对碳离子束辐照更敏感,而抗氧化系统在二者辐照敏感性差异中起着重要作用。
基金the National Natural Science Foundation of China(Nos.12005271 and 12005273)the National Key Research and Development Program of China(No.E022223Y)+1 种基金the Western Talent Program of Chinese Academy of Sciences(No.29Y86205)the Key Deployment Project of Chinese Academy of Sciences(No.KFZD-SW-222).
文摘The use of carbon-ion radiotherapy(CIRT)is gradually increasing.Owing to the generation of high-energy secondary neutrons during CIRT,its use presents new challenges in radiation protection.Thus,secondary neutron dose distributions must be explored and evaluated under clinical scenarios based on different treatment configurations.However,neutron dose and energy spectrum measurements are often difficult.This can be primarily attributed to the inherent limitations of most neutron detectors,such as their unsuitability for spectral measurements and inaccurate responses to neutrons with energies above 20 MeV.Numerical calculation methods based on probabilistic statistical theory are fast and convenient for neutron dose evaluation.In this study,external secondary neutron doses at the heavy ion medical machine in Wuwei,which is equipped with a passive beam delivery system,were calculated using the Monte Carlo method.The dependence of neutron doses on various treatment parameters(incident carbon-ion beam energy,spatial location,field size,and spread-out Bragg peak(SOBP)width)was investigated.Furthermore,the feasibility of applying an analytical model to predict the ambient dose equivalent was verified.For the combination involving an energy of 400 MeV=u and SOBP width of 6 cm,the ambient dose equivalent per therapeutic dose(H=D)at the isocenter was 79.87 mSv=Gy:The H=D value decreased rapidly with increasing spatial distance and slightly with increasing aperture size and SOBP width.The H=D values derived from the Monte Carlo simulations were in good agreement with the results reported in the literature.The analytical model could be used to quickly predict the H=D value along the incidence direction of the beam with an error of less than 20%.Thus,our study contributes to the understanding of the relationship between neutron radiation and treatment configuration parameters,which establishes a basis for predicting non-therapeutic radiation doses in CIRT.
基金Supported by the superintendents'foundation of Institute of Modern Physics,Chinese Academy of Sciences(0906020SZO)
文摘Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years,but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found.In this study,a color-leaf mutant with purple leaves,stems and petals was isolated from clones of Wandering Jew irradiated by 95.8 MeV/u carbon ion beam.The concentration and histological distribution of leaf pigment were surveyed in wild type and mutant.In mutant,contents of total chlorophylls (Chl),chlorophyll a (Chl a),chlorophyll b (Chl b) and carotenoids (Car) decreased significantly,while concentration of the anthocyanins was 6.2-fold higher than that of wild type.Further composition analysis of anthocyanins by electrospray ionization mass spectrometry (ESI-MS) indicated that the purple pigmentation of leaves in mutant was caused by accumulation of petunidin anthocyanin.Microscopic examination showed that most petunidin anthocyanin accumulated in the lower epidermis,and little in vascular parenchyma of mutant,while there was no pigment in wild type.Meanwhile,in spongy parenchyma of mutant we observed little Chl,which the wild type abounds in.In conclusion,the color-leaf mutant of Wandering Jew induced by irradiation of carbon ions was improved in ornamental value,and it could be contribute to variation in level,component and distribution of foliar pigment.The possible mutation mechanisms were discussed.
