Alpha-alumina(α-Al_2O_3) platelets were prepared via solid-state reaction using pseudo-boehmite as the starting material, while NH_4F and nano-SiO_2 were used as additives, and nitric acid was used as the binder. The...Alpha-alumina(α-Al_2O_3) platelets were prepared via solid-state reaction using pseudo-boehmite as the starting material, while NH_4F and nano-SiO_2 were used as additives, and nitric acid was used as the binder. The effect of these additives on properties of the alumina platelets was determined via scanning electron microscopy, X-ray diffraction, and measurements of the surface area and silicon content. A mechanism governing their role in the synthesis process was proposed. The results indicated that NH_4F could promote the formation of highly crystalline platelets. Addition of nano-SiO_2 could lead to increase in the diameter and reduction in the thickness of the platelets, and could also prevent their transformation to α-Al_2O_3. This addition weakened the effect of NH_4F because of the reaction of nano-SiO_2 with F-species and the formation of volatile SiF_4.展开更多
Primary rat tracheal epithelium (RTE) cells can be transformed in vitro by a-particles irradiation. Oneout of 3 isolated morphologically trans formed colonies gave rise to an immortal cell line and ultimately be-came ...Primary rat tracheal epithelium (RTE) cells can be transformed in vitro by a-particles irradiation. Oneout of 3 isolated morphologically trans formed colonies gave rise to an immortal cell line and ultimately be-came neoplastic by successive passaging. Cytogenetic analysis was performed on the cell line in order to un-derstand how the specific chromosome alterations participate in the process of neoplastic transformation ofRTE cells. The 5th, 18th, 39th passage cells and the colony cells isolated from soft agar (SA) culturing ofthe 4oth passage cells were analyzed. The results showed that the 2Oth passage cells were nontumorigenic,but the 4Oth passage cells were tumorigenic. The increase of the length of the long arrn of chromosome 15(15q+ ) was frequent at the 5th passage (67. 8% ), especially in SA cells in which it occurred in a clonalfashion (100% ) Therefore, 15q+ might be the critical gene lesion after a-particles irradiation. Mono-somy of chromosome 8 that occurred frequently at passage 5 (54% ) and 40 (53% ) might be correlatedwith earlier transformation of RTE cells. In addition, three marker chromosomes (Ml, M2 and M3)showed a passage-dependent increase’ In particular M1 and M2 that were highly frequent at passage 39(90% ) suggested that they might play an important role in the process of cell transformation.展开更多
基金supported by the Technology Development(Commission) Project of SINOPEC Catalyst Co.Ltd(Grant No.14-05-01)
文摘Alpha-alumina(α-Al_2O_3) platelets were prepared via solid-state reaction using pseudo-boehmite as the starting material, while NH_4F and nano-SiO_2 were used as additives, and nitric acid was used as the binder. The effect of these additives on properties of the alumina platelets was determined via scanning electron microscopy, X-ray diffraction, and measurements of the surface area and silicon content. A mechanism governing their role in the synthesis process was proposed. The results indicated that NH_4F could promote the formation of highly crystalline platelets. Addition of nano-SiO_2 could lead to increase in the diameter and reduction in the thickness of the platelets, and could also prevent their transformation to α-Al_2O_3. This addition weakened the effect of NH_4F because of the reaction of nano-SiO_2 with F-species and the formation of volatile SiF_4.
文摘Primary rat tracheal epithelium (RTE) cells can be transformed in vitro by a-particles irradiation. Oneout of 3 isolated morphologically trans formed colonies gave rise to an immortal cell line and ultimately be-came neoplastic by successive passaging. Cytogenetic analysis was performed on the cell line in order to un-derstand how the specific chromosome alterations participate in the process of neoplastic transformation ofRTE cells. The 5th, 18th, 39th passage cells and the colony cells isolated from soft agar (SA) culturing ofthe 4oth passage cells were analyzed. The results showed that the 2Oth passage cells were nontumorigenic,but the 4Oth passage cells were tumorigenic. The increase of the length of the long arrn of chromosome 15(15q+ ) was frequent at the 5th passage (67. 8% ), especially in SA cells in which it occurred in a clonalfashion (100% ) Therefore, 15q+ might be the critical gene lesion after a-particles irradiation. Mono-somy of chromosome 8 that occurred frequently at passage 5 (54% ) and 40 (53% ) might be correlatedwith earlier transformation of RTE cells. In addition, three marker chromosomes (Ml, M2 and M3)showed a passage-dependent increase’ In particular M1 and M2 that were highly frequent at passage 39(90% ) suggested that they might play an important role in the process of cell transformation.
