We report on XMM Newton guaranteed time observations of the Seyfert galaxy MCG 6 30 15. Confirming earlier results from ASCA, BeppoSAX , and RXTE, the fluorescent FeKα line in this source is found to be extremely bro...We report on XMM Newton guaranteed time observations of the Seyfert galaxy MCG 6 30 15. Confirming earlier results from ASCA, BeppoSAX , and RXTE, the fluorescent FeKα line in this source is found to be extremely broad. Modeling the line using a line emissivity I(r)∝r -β we find β>3.This indicates that most line emission comes from the innermost regions around the central black hole. The emissivity coefficient is steeper than expected for standard models for the Fe Kα emission. This steep emission might be due to energy extraction from a rotating black hole.展开更多
The title compound (C20H30N4O6, Mr = 422.48) was synthesized and its crystal structure was determined by X-ray diffraction method. It crystallizes in the triclinic system, space group P with cell parameters: a = 8.330...The title compound (C20H30N4O6, Mr = 422.48) was synthesized and its crystal structure was determined by X-ray diffraction method. It crystallizes in the triclinic system, space group P with cell parameters: a = 8.330(2), b = 8.468(2), c = 16.017(3) ? ?= 97.30(3), ?= 92.33(3), ?= 103.94(3)? V = 1084.7(4) ?, Dc = 1.294 g/cm3, Z = 2, F(000) = 452 and ?= 0.096 mm-1. The structure was refined to R = 0.0483 for 3732 observed reflections with I > 2s(I) and wR = 0.1335 for 4828 unique reflections. The hydantoin rings are planar and the two ring planes of one molecule are paralleled to each other.展开更多
文摘We report on XMM Newton guaranteed time observations of the Seyfert galaxy MCG 6 30 15. Confirming earlier results from ASCA, BeppoSAX , and RXTE, the fluorescent FeKα line in this source is found to be extremely broad. Modeling the line using a line emissivity I(r)∝r -β we find β>3.This indicates that most line emission comes from the innermost regions around the central black hole. The emissivity coefficient is steeper than expected for standard models for the Fe Kα emission. This steep emission might be due to energy extraction from a rotating black hole.
基金This work was supported by the Educational Department of Jiangsu Province, China (No. 04KJA180110)the Personnel Department of Jiangsu Province, China (No. 06-B-040)the Nantong Municipality of Jiangsu Province, China (No. S40057 and S5040).
文摘近来研究发现,细胞因子白介素-6(interleukin-6,IL-6)不仪是重要的免疫调节因子,而且也是重要的神经调节因子。中枢神经系统中IL-6的作用是复杂的,尤其是对脑损伤时IL-6所发挥的作用及其作用机制尚不十分清楚。为此,我们利用N-甲基-D-天门冬氨酸(N-methyl-D-aspartate,NMDA)处理小脑颗粒神经元引起急性损伤的细胞模型,探讨IL-6对神经元损伤的保护及其作用机制。取出生后8 d幼鼠的小脑,进行小脑颗粒神经元培养。将IL-6(5或10 ng/mL)加入到小脑颗粒神经元的培养液中孵育8 d,然后用NMDA(100μmol／L)刺激小脑颗粒神经元30 min以造成神经元损伤。用噻唑兰(methyl-thiazole tetrazolium,MTT)比色法检测神经元的活性;用末端脱氧核苷酸转移酶介导的原位缺口末端标记(terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling,TUNEL)法检测神经元的凋亡;用激光扫描共聚焦显微镜(confocal laser scanning microscope,CLSM)观察神经元内游离Ca2+浓度的动态变化。用抗gp130单克隆抗体(75 ng／mL)抑制IL-6的活性,然后观察IL-6抗NMDA神经毒性作用的变化;并利用Western blot法检测IL-6对小脑颗粒神经元表达IL-6的细胞内信号转导蛋白——信号转导子和转录激活子3(signal transducer and activator of transcription 3,STAT3)和细胞外信号调节激酶(extracellular signal regulated kinase 1／2,ERK1／2)磷酸化水平的影响。NMDA刺激未经IL-6处理的小脑颗粒神经元,导致神经元活性降低、神经元凋亡增加和神经元内Ca2+超载。NMDA刺激经IL-6慢性预处理的小脑颗粒神经元,其损伤程度与未经IL-6处理的神经元相比明显减轻,包括神经元活性明显增强、神经元凋亡显著减少和神经元内Ca2+超载减轻。抗gp130抗体可阻断IL-6减轻NMDA激发的神经元内Ca2+超载的作用;经IL-6慢性处理的小脑颗粒神经元,其细胞内STAT3和ERK1／2的磷酸化水平显著增加。结果表明,IL-6能保护神经元抵抗由NMDA诱导的兴奋性神经毒性,此神经保护机制与IL-6减轻神经元内Ca2+超载密切相关,而且可能通过激活神经元内IL-6的信号转导路径调节细胞内的基因表达而实现。
基金This project was supported by the National Natural Science Foundation of China (No 39870983)
文摘The title compound (C20H30N4O6, Mr = 422.48) was synthesized and its crystal structure was determined by X-ray diffraction method. It crystallizes in the triclinic system, space group P with cell parameters: a = 8.330(2), b = 8.468(2), c = 16.017(3) ? ?= 97.30(3), ?= 92.33(3), ?= 103.94(3)? V = 1084.7(4) ?, Dc = 1.294 g/cm3, Z = 2, F(000) = 452 and ?= 0.096 mm-1. The structure was refined to R = 0.0483 for 3732 observed reflections with I > 2s(I) and wR = 0.1335 for 4828 unique reflections. The hydantoin rings are planar and the two ring planes of one molecule are paralleled to each other.
