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191.
为配合南水北调工程建设, 2005~2006年河南省文物考古研究所在荥阳市薛村附近的南水北调工地进行抢救性考古发掘, 在薛村遗址揭露出大量的古地震遗迹, 主要有地堑、地裂缝和古代文化遗迹的错位等. 根据古地震遗迹与文化层(或灰坑)之间的相互关系, 初步判断古地震发生在商代前期, 大致时间在二里岗下层晚期到二里岗上层之间, 进而通过灰坑中木炭的AMS14C测年, 确定这次古地震发生在(2910±35)~(3165±35) a BP (或(3160±35) a BP)之间, 亦即日历年龄1260~1520 BC(或1510 BC)之间. 薛村史前地震遗迹迹象清楚, 年代确凿, 填补了中原地区这一阶段古地震记录的空白. 这一发现不仅加深了对史前地震的了解, 拓宽了古地震研究的内容和方法, 而且也为正在建设中的南水北调工程, 提供了重要的科学依据. 相似文献
192.
Shen Xianrong Ji Dongmei Hu Youqing Jia Fuxing Deng Xinxian Wang Ling Chu Zhiyong Jiang Dingwen Lei Chengxiang Huang Jiansheng Hu Xinran Ren Daming 《科学通报(英文版)》2001,46(24):2037-2042
Sequences encoding PF4 (58–70) and TSP1 (429–459) were linked to yield a single gene TSF which encodes the fuse-protein of TSF. The gene was cloned into a pGEX-2T expression vector to generate a protein GST-TSF, which was strongly expressed inE. coli. The purified GST-TSF was degraded with thrombin to generate the protein TSF. With the methods of MTT and wound repair assay, the effects of TSF on the proliferation and migration of EC were detected, respectively. The results showed that TSF significantly suppressed BAEC proliferation and migration in a dose-dependent manner. The fuse protein GST-TSF, and the peptides PF4 (58–70) and TSP1 (429–459) also inhibited BAEC proliferation and migration, respectively, but their inhibition rates were not as high as TSF. Using the CAM assay, it was shown that TSF, GST-TSF, PF4 (58–70) and TSP1 (429–459) inhibited angiogenesis in chick CAM potentially, the effect of TSF was the highest.In vivo, the growth of Lewis lung carcinoma was potently inhibited by TSF treatment, and the inhibition rate was 68.75% at a dose of 1.00 μmol/kg · d. These findings suggest that the design on TSF gene was successful, and TSF with its anti-angiogenic and anti-tumor activity, should be a useful source of the inhibitor. 相似文献
193.
Shiheng Tao Xiaoming Liu Jianhua Chu Rongmei Zhang Liping Du Zewei Luo 《科学通报(英文版)》2001,46(5):358-363
Modeling linkage disequilibria (LD) between genes usually observed in admixed natural populations has been shown an effective approach in high-resolution mapping of disease genes in humans. A prerequisite to obtain accurate estimation of recombination fraction between genes at a marker locus and the disease locus using the approach is a reliable prediction of the proportion of the admixture populations. The present study suggested the use of gene frequencies to predict the estimate of the admixture proportion based on the observation that the gene frequencies are much more stable quantities than the haplotype frequencies over evolution of the population. In this paper, we advanced the theory and methods by which the decay rate of nonlinear term of LD in admixed population may be used to estimate the recombination fraction between the genes. Theoretical analysis and simulation study indicate that, the larger the difference of gene frequencies between parental populations and the more closely the admixture proportion approaches 0.5, the more important the nonlinear term of the LD in the admixed population, and hence the more informative such admixed populations in the high-resolution gene mapping practice. 相似文献
194.
A defined range of guard cell calcium oscillation parameters encodes stomatal movements. 总被引:59,自引:0,他引:59
G J Allen S P Chu C L Harrington K Schumacher T Hoffmann Y Y Tang E Grill J I Schroeder 《Nature》2001,411(6841):1053-1057
Oscillations in cytosolic calcium concentration ([Ca2+]cyt) are central regulators of signal transduction cascades, although the roles of individual [Ca2+]cyt oscillation parameters in regulating downstream physiological responses remain largely unknown. In plants, guard cells integrate environmental and endogenous signals to regulate the aperture of stomatal pores and [Ca2+]cyt oscillations are a fundamental component of stomatal closure. Here we systematically vary [Ca2+]cyt oscillation parameters in Arabidopsis guard cells using a 'calcium clamp' and show that [Ca2+]cyt controls stomatal closure by two mechanisms. Short-term 'calcium-reactive' closure occurred rapidly when [Ca2+]cyt was elevated, whereas the degree of long-term steady-state closure was 'calcium programmed' by [Ca2+]cyt oscillations within a defined range of frequency, transient number, duration and amplitude. Furthermore, in guard cells of the gca2 mutant, [Ca2+]cyt oscillations induced by abscisic acid and extracellular calcium had increased frequencies and reduced transient duration, and steady-state stomatal closure was abolished. Experimentally imposing [Ca2+]cyt oscillations with parameters that elicited closure in the wild type restored long-term closure in gca2 stomata. These data show that a defined window of guard cell [Ca2+]cyt oscillation parameters programs changes in steady-state stomatal aperture. 相似文献
195.
196.
简要介绍核级蓄电池模拟地震试验的试件选择、安装环境的模拟以及试验的基本程序,重点讨论地震荷载作用期间蓄电池连续放电特性,以及试验前后蓄电池容量的考核等特性问题。验证了样机设计的可靠性及合理性,为改进设计及现场安装提供了依据。还论证了国产蓄电池应用在核电领域中的可行性。 相似文献
197.
CREB is activated in EPO induced HEL cells 总被引:1,自引:0,他引:1
198.
With the 2.16 m telescope at Beijing Astronomical Observatory, it is identified that a compact X-ray source detected by ROSAT
located in the vicinity of 5′.9 from the LINER galaxy NGC4579 is a quasar with a redshift z = 0.106. A further analysis indicates
that this quasar is possibly ejected from NGC4579. 相似文献
199.
The two-step monsoon changes of the last deglaciation recorded in tropical Maar Lake Huguangyan, southern China 总被引:3,自引:0,他引:3
Wenyuan Wang Jiaqi Liu Dongsheng Liu Tungsheng Liu Ping’an Peng Houyuan Lu Zhaoyan Gu Guoqiang Chu J. Negendank Xiangjun Luo J. Mingram 《科学通报(英文版)》2000,45(16):1529-1532
The concentrations of biogenic silica, total organic carbon, total nitrogen and total hydrogen inferred from the sediments
of tropical Maar Lake Huguangyan, southern China, provide a climate record of the last déglaciation with century resolution.
The records fully demonstrate the existence of the two-step shape of the last déglaciation in tropic East Asia, and they point
out noticeable differences between the low and high latitudes in the Northern Hemisphere. Thus, the Boiling first warming
at the last deglaciation in the low latitude may have preceded that of the high latitude, whereas the cooling of the Younger
Dryas occurred synchronously in the two regions. These results likely suggest that the links between the low and high latitude
climates in the Northern Hemisphere during this period are complexity. 相似文献
200.
新型炎症显像剂的初步研究 总被引:1,自引:1,他引:0
对柠檬酸(Cit)、酒石酸(Tar)、DL-苹果酸(DL-Mal)、L-苹果酸(L-Mal)和D-葡萄糖二酸(D-Gca)等5种含有羟基和羟在的小分子化合物的^99mTc标记条件以及亲炎症的生物性能进行了初步研究。根据它们的最佳标记条件,分别对其进行标记。标记率均大于90%,这5种配合物和^99mTcO4^-4(P)的松节油致炎小鼠中的生物分布结果表明,炎症模型脓肿与肌肉的质量活度分数之比值(am 相似文献