The relative biological effectiveness （RBE） of carbon ions with linear energy transfer （LET） of 172 keV/μm and 13.7 keV/μm were determined in this study. The clonogenic survival and premature terminal differenti...The relative biological effectiveness （RBE） of carbon ions with linear energy transfer （LET） of 172 keV/μm and 13.7 keV/μm were determined in this study. The clonogenic survival and premature terminal differentiation were measured on normal human fibroblasts AG01522C and NHDF after exposure of the cells to 250 kV X-rays and carbon ions with different qualities. RBE was determined for these two biological end points. The results showed that the measured RBE10 with a survival fraction of 10% was 3.2 for LET 172 keV/μm, and 1.33 for LET 13.7 keV/μm carbon ions. RBE for a doubling of post-mitotic fibroblasts （PMF） in the population was 2.8 for LET 172 keV/μm, and 1 for LET 13.7 keV/μm carbon ions. For the carbon ion therapy, a high RBE value on the Bragg peak results in a high biological dose on the tumour. The tumour cells can be killed effectively. At the same time, the dose on healthy tissue would be reduced accordingly. This will lighten the late effect such as fibrosis on normal tissue.展开更多
The early RBE of the bone marrow in mice after studied irradiation with fast neutrons(35 MeVp→Be) was studied.60Co-γ ray was used for referent beams.Using the dos.making 50% loss of the nucleated cells of bone marro...The early RBE of the bone marrow in mice after studied irradiation with fast neutrons(35 MeVp→Be) was studied.60Co-γ ray was used for referent beams.Using the dos.making 50% loss of the nucleated cells of bone marrow in mice relative to control group mice to calculated the RBE value which was 2.13±0.18.Meanwhile,the relationship of the RBE values and the dose of neutrons was noted.On log-log plot the RBE values decrease with increasing dose of fast neutrons and it is consistent with a slope of -0.39± 0.10.The α/β ratios were estimated from linear-quadratic model of cell survival,they are 14.4±1.30 Gy for fast neutrons and 0.83±0.10 Gy for γ-ray,respectively.展开更多
The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization (OECD), and the EC50(median growth...The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization (OECD), and the EC50(median growth concentration)values were obtained. The inhibition of RE on the growth of rice and rape in red soil and on the growth of soybean in yellow fluvo-aquic soil is higher with stronger poison effects. Compared with other heavy metals such as Hg, Cd, Pb, As, the poison of RE on crops is weaker.展开更多
Purpose: The recommended value for the relative biological effectiveness (RBE) of proton beams is currently assumed to be 1.1. However, there is increasing evidence that RBE increases towards the end of proton beam ra...Purpose: The recommended value for the relative biological effectiveness (RBE) of proton beams is currently assumed to be 1.1. However, there is increasing evidence that RBE increases towards the end of proton beam range that may increase the biological effect of proton beam in the distal regions of the dose deposition. Methods: A computational approach is presented for estimating the biological effect of the proton beam. It includes a method for calculating the dose averaged linear energy transfer (LET) along the measured Bragg peak and published LET to RBE conversion routine. To validate the proposed method, we have performed Monte Carlo simulations of the pristine Bragg peak at various beam energies and compared the analysis with the simulated results. A good agreement within 5% is observed between the LET analysis of the modeled Bragg peaks and Monte Carlo simulations. Results: Applying the method to the set of Bragg peaks measured at a proton therapy facility we have estimated LET and RBE values along each Bragg peak. Combining the individual RBE-weighted Bragg peaks with known energy modulation weights we have calculated the RBE-weighted dose in the modulated proton beam. The proposed computational method provides a tool for calculating dose averaged LET along the measured Bragg peak. Conclusions: Combined with a model to convert LET into RBE, this method enables calculation of RBE-weighted dose both in pristine Bragg peak and in modulated beam in proton therapy.展开更多
背景:高密度脂蛋白是指与脂代谢有关的高密度脂蛋白,但研究表明其功能不仅局限于脂代谢范畴;同时运动调节高密度脂蛋白的活性和数量,但最佳的运动方式有待于研究。目的:总结高密度脂蛋白的生物学功能及运动调节高密度脂蛋白研究进展,展...背景:高密度脂蛋白是指与脂代谢有关的高密度脂蛋白,但研究表明其功能不仅局限于脂代谢范畴;同时运动调节高密度脂蛋白的活性和数量,但最佳的运动方式有待于研究。目的:总结高密度脂蛋白的生物学功能及运动调节高密度脂蛋白研究进展,展望了高密度脂蛋白研究的可能方向,旨在为健身训练方案的制定提供理论支持,为后续研究提供参考;方法:以关键词"HDL and exercise,HDL and biological function"搜索Pub Med数据库,筛选到1990至2015年间文章98篇;按纳入、排除标准最后纳入文献44篇。结果与结论:高密度脂蛋白主要功能包括介导糖、蛋白质、脂肪代谢、抗炎、抗氧化及介导胰岛素分泌的功能,同时总结运动对高密度脂蛋白浓度,分子数及组份影响的研究。研究表明抗阻与耐力组合训练提高高密度脂蛋白浓度及功能效果最显著。展开更多
基金the"Xi Bu Zhi Guang"Project of Chinese Academy of Sciences(No.O606180XBO)
文摘The relative biological effectiveness （RBE） of carbon ions with linear energy transfer （LET） of 172 keV/μm and 13.7 keV/μm were determined in this study. The clonogenic survival and premature terminal differentiation were measured on normal human fibroblasts AG01522C and NHDF after exposure of the cells to 250 kV X-rays and carbon ions with different qualities. RBE was determined for these two biological end points. The results showed that the measured RBE10 with a survival fraction of 10% was 3.2 for LET 172 keV/μm, and 1.33 for LET 13.7 keV/μm carbon ions. RBE for a doubling of post-mitotic fibroblasts （PMF） in the population was 2.8 for LET 172 keV/μm, and 1 for LET 13.7 keV/μm carbon ions. For the carbon ion therapy, a high RBE value on the Bragg peak results in a high biological dose on the tumour. The tumour cells can be killed effectively. At the same time, the dose on healthy tissue would be reduced accordingly. This will lighten the late effect such as fibrosis on normal tissue.
文摘The early RBE of the bone marrow in mice after studied irradiation with fast neutrons(35 MeVp→Be) was studied.60Co-γ ray was used for referent beams.Using the dos.making 50% loss of the nucleated cells of bone marrow in mice relative to control group mice to calculated the RBE value which was 2.13±0.18.Meanwhile,the relationship of the RBE values and the dose of neutrons was noted.On log-log plot the RBE values decrease with increasing dose of fast neutrons and it is consistent with a slope of -0.39± 0.10.The α/β ratios were estimated from linear-quadratic model of cell survival,they are 14.4±1.30 Gy for fast neutrons and 0.83±0.10 Gy for γ-ray,respectively.
文摘The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization (OECD), and the EC50(median growth concentration)values were obtained. The inhibition of RE on the growth of rice and rape in red soil and on the growth of soybean in yellow fluvo-aquic soil is higher with stronger poison effects. Compared with other heavy metals such as Hg, Cd, Pb, As, the poison of RE on crops is weaker.
文摘Purpose: The recommended value for the relative biological effectiveness (RBE) of proton beams is currently assumed to be 1.1. However, there is increasing evidence that RBE increases towards the end of proton beam range that may increase the biological effect of proton beam in the distal regions of the dose deposition. Methods: A computational approach is presented for estimating the biological effect of the proton beam. It includes a method for calculating the dose averaged linear energy transfer (LET) along the measured Bragg peak and published LET to RBE conversion routine. To validate the proposed method, we have performed Monte Carlo simulations of the pristine Bragg peak at various beam energies and compared the analysis with the simulated results. A good agreement within 5% is observed between the LET analysis of the modeled Bragg peaks and Monte Carlo simulations. Results: Applying the method to the set of Bragg peaks measured at a proton therapy facility we have estimated LET and RBE values along each Bragg peak. Combining the individual RBE-weighted Bragg peaks with known energy modulation weights we have calculated the RBE-weighted dose in the modulated proton beam. The proposed computational method provides a tool for calculating dose averaged LET along the measured Bragg peak. Conclusions: Combined with a model to convert LET into RBE, this method enables calculation of RBE-weighted dose both in pristine Bragg peak and in modulated beam in proton therapy.
文摘背景:高密度脂蛋白是指与脂代谢有关的高密度脂蛋白,但研究表明其功能不仅局限于脂代谢范畴;同时运动调节高密度脂蛋白的活性和数量,但最佳的运动方式有待于研究。目的:总结高密度脂蛋白的生物学功能及运动调节高密度脂蛋白研究进展,展望了高密度脂蛋白研究的可能方向,旨在为健身训练方案的制定提供理论支持,为后续研究提供参考;方法:以关键词"HDL and exercise,HDL and biological function"搜索Pub Med数据库,筛选到1990至2015年间文章98篇;按纳入、排除标准最后纳入文献44篇。结果与结论:高密度脂蛋白主要功能包括介导糖、蛋白质、脂肪代谢、抗炎、抗氧化及介导胰岛素分泌的功能,同时总结运动对高密度脂蛋白浓度,分子数及组份影响的研究。研究表明抗阻与耐力组合训练提高高密度脂蛋白浓度及功能效果最显著。
