Bacteriophage morphogenesis is a model system for investigating sequential molecular assembly. The Mu phage is one of the most classical Myoviridae. Although it is well known as a mobile genetic element, the details o...Bacteriophage morphogenesis is a model system for investigating sequential molecular assembly. The Mu phage is one of the most classical Myoviridae. Although it is well known as a mobile genetic element, the details of its morphogenesis remain unclear. Analysis of conditional lethal mutants and genome analysis of the Mu phage have suggested that genes 42, 43, 44, 45, 46, 47, and 48 are essential for its baseplate assembly. Since we have already reported X-ray structures of the products of genes 44 (gp44) and 45 (gp45), we here tried to purify the remaining Mu phage baseplate subunits, gp42, gp43, gp46, gp47, and gp48, to investigate the baseplate assembly process. In the case of gp42 expression, the transformed E. coli cells showed growth inhibition after induction and no gp42 fractions were observed. However, gp43, gp46, gp47, and gp48 were successfully expressed and purified, although gp48 could not be applied to further analysis, because the amount of soluble fraction was very low. Based on analytical ultracentrifugation, we concluded that gp43 formed a monomer, gp46 was a monomer, and gp47 occurred as both a monomer and dimer in solution. Moreover, we found that gp43 and gp45 formed an intermediate complex in the baseplate assembly process.展开更多
The ecological greening technology of the bare rock area of the arbor governance be-longs to the field of ecological environment restoration, selection of suitable arbors for vegetation restoration in bare rock area, ...The ecological greening technology of the bare rock area of the arbor governance be-longs to the field of ecological environment restoration, selection of suitable arbors for vegetation restoration in bare rock area, vegetation recovery is the primary approach to governance the ecological environment of bare rock area. The reconstruction of bare rock area arbor-shrub-grass ecosystems is a global environmental science problem. Paying attention to Geological conditions with rich rock fissures and abundant groundwater in these fissures, following the idea to reconstruct ecosystem from arbor to shrub and grass and the principle one tree in a baseplate, authors develop a baseplate technique for tree planting in bare rock area. The baseplate includes the parent body, the root, and the cover to prevent evaporation. Especially, there are filled in nutritional soil for the parent body and the root, and the composition of nutritional soil are selected by test in laboratory, while optimal mix ratio of the composition is obtained. Then, application method in field is put forward. The technique can guarantee survival at early stage and growth in the later for tree planting in the baseplate. In particular, the root provides a good channel to guide tree roots into fissure rock and absorb groundwater in rock. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area in the world.展开更多
目的研究碳纤维体位固定板的透射系数及对椎体转移瘤放射治疗剂量的影响。方法CT定位机下扫描碳纤维体位固定板,计算体位固定板在不同角度下的衰减系数,并与相同条件下的实测体位固定板衰减系数比较,分析放射治疗计划系统的准确性;另选...目的研究碳纤维体位固定板的透射系数及对椎体转移瘤放射治疗剂量的影响。方法CT定位机下扫描碳纤维体位固定板,计算体位固定板在不同角度下的衰减系数,并与相同条件下的实测体位固定板衰减系数比较,分析放射治疗计划系统的准确性;另选择10例椎体转移瘤患者,其中男性5例,女性5例;年龄50~76岁,中位年龄65岁;病灶均位于双肾之间椎体上。在不勾画体位固定板的CT图像上设计无板计划,无板计划完成后将此计划移植到勾画体位固定板的CT图像上,并进行剂量计算,比较无板计划、有板计划靶区和危及器官(OAR)的剂量学差异。结果体位固定板在不同机架角度下的实际衰减系数为0.966~0.995,放射治疗计划系统计算得到的体位固定板的衰减系数与实际测量得到的衰减系数偏差在0.62%以内;对于椎体转移瘤计划,体位固定板勾画参与剂量计算后,靶区的受照剂量明显降低,平均降低2%左右。对于靶区的适形性指数(CI)、均匀性指数(HI),体位固定板的勾画会导致靶区的CI显著降低,差异有统计学意义(0.849±0.051 vs 0.760±0.037。P<0.05),而对HI影响不大,差异无统计学意义(P>0.05)。对OAR,有板计划的剂量体积(V_(10)、V_(20)、V_(30))、D_(mean)、D_(max)均比无板计划偏低,其中小肠、左肾、右肾的剂量体积减少百分点均在1%以内;脊髓D_(max)减少了0.87 cGy(2.3%),且差异均有统计学意义[(38.85±0.89)cGy vs(37.99±0.77)cGy。P<0.05]。结论碳纤维体位固定板对椎体转移瘤患者的放射治疗剂量有一定的影响,为确保靶区剂量准确性,建议在治疗计划设计时考虑体位固定板,使其参与剂量计算。展开更多
文摘Bacteriophage morphogenesis is a model system for investigating sequential molecular assembly. The Mu phage is one of the most classical Myoviridae. Although it is well known as a mobile genetic element, the details of its morphogenesis remain unclear. Analysis of conditional lethal mutants and genome analysis of the Mu phage have suggested that genes 42, 43, 44, 45, 46, 47, and 48 are essential for its baseplate assembly. Since we have already reported X-ray structures of the products of genes 44 (gp44) and 45 (gp45), we here tried to purify the remaining Mu phage baseplate subunits, gp42, gp43, gp46, gp47, and gp48, to investigate the baseplate assembly process. In the case of gp42 expression, the transformed E. coli cells showed growth inhibition after induction and no gp42 fractions were observed. However, gp43, gp46, gp47, and gp48 were successfully expressed and purified, although gp48 could not be applied to further analysis, because the amount of soluble fraction was very low. Based on analytical ultracentrifugation, we concluded that gp43 formed a monomer, gp46 was a monomer, and gp47 occurred as both a monomer and dimer in solution. Moreover, we found that gp43 and gp45 formed an intermediate complex in the baseplate assembly process.
文摘The ecological greening technology of the bare rock area of the arbor governance be-longs to the field of ecological environment restoration, selection of suitable arbors for vegetation restoration in bare rock area, vegetation recovery is the primary approach to governance the ecological environment of bare rock area. The reconstruction of bare rock area arbor-shrub-grass ecosystems is a global environmental science problem. Paying attention to Geological conditions with rich rock fissures and abundant groundwater in these fissures, following the idea to reconstruct ecosystem from arbor to shrub and grass and the principle one tree in a baseplate, authors develop a baseplate technique for tree planting in bare rock area. The baseplate includes the parent body, the root, and the cover to prevent evaporation. Especially, there are filled in nutritional soil for the parent body and the root, and the composition of nutritional soil are selected by test in laboratory, while optimal mix ratio of the composition is obtained. Then, application method in field is put forward. The technique can guarantee survival at early stage and growth in the later for tree planting in the baseplate. In particular, the root provides a good channel to guide tree roots into fissure rock and absorb groundwater in rock. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area. Test in field shows that the baseplate technique has strong practicality in vegetation recovery of bare rock area in the world.
文摘目的研究碳纤维体位固定板的透射系数及对椎体转移瘤放射治疗剂量的影响。方法CT定位机下扫描碳纤维体位固定板,计算体位固定板在不同角度下的衰减系数,并与相同条件下的实测体位固定板衰减系数比较,分析放射治疗计划系统的准确性;另选择10例椎体转移瘤患者,其中男性5例,女性5例;年龄50~76岁,中位年龄65岁;病灶均位于双肾之间椎体上。在不勾画体位固定板的CT图像上设计无板计划,无板计划完成后将此计划移植到勾画体位固定板的CT图像上,并进行剂量计算,比较无板计划、有板计划靶区和危及器官(OAR)的剂量学差异。结果体位固定板在不同机架角度下的实际衰减系数为0.966~0.995,放射治疗计划系统计算得到的体位固定板的衰减系数与实际测量得到的衰减系数偏差在0.62%以内;对于椎体转移瘤计划,体位固定板勾画参与剂量计算后,靶区的受照剂量明显降低,平均降低2%左右。对于靶区的适形性指数(CI)、均匀性指数(HI),体位固定板的勾画会导致靶区的CI显著降低,差异有统计学意义(0.849±0.051 vs 0.760±0.037。P<0.05),而对HI影响不大,差异无统计学意义(P>0.05)。对OAR,有板计划的剂量体积(V_(10)、V_(20)、V_(30))、D_(mean)、D_(max)均比无板计划偏低,其中小肠、左肾、右肾的剂量体积减少百分点均在1%以内;脊髓D_(max)减少了0.87 cGy(2.3%),且差异均有统计学意义[(38.85±0.89)cGy vs(37.99±0.77)cGy。P<0.05]。结论碳纤维体位固定板对椎体转移瘤患者的放射治疗剂量有一定的影响,为确保靶区剂量准确性,建议在治疗计划设计时考虑体位固定板,使其参与剂量计算。
