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The results showed that:(1) Many proliferating cells were distributed unevenly in the ventricular zone of telencephalon, and the [3H] labeled cells were found to be populated in the lateral ventricular zone of neostriatum at brain level L12~L14,forming proliferation "hot spots";(2) Having underwent mitosis twice, the proliferative cells in the VZ began to migrate laterally 6 days after intramuscular injection of [3H] thymidine, and these migrating precursor cells terminated at their targets and differentiated into new neurons on the 30th day.

结果发现：①端脑室带区中存在不均匀分布的[3H]标记细胞，大量标记细胞分布在端脑尾侧新纹状体水平(L1～L14)的VZ，形成标记细胞的&热点&区；②标记细胞经两次有丝分裂后，大约在肌肉注射[3H]的第6天后开始从VZ向外迁移，在30天左右到达目的脑区并分化成为成熟神经元。

Neural stem cells are the common precursor cell of neuron and neuroepithelial cell.

神经干细胞是神经元和神经胶质细胞的共同前体细胞。

Films of carbon nanofibers have been grown on the block-type CNTs substrate impregnated with an aqueous nickelous nitrate solution as catalyst precursor.

通过在碳纳米管孔隙中浸润镍基溶液，在气相生长的条件下，在压制体表面生长出碳纳米纤维薄膜。

This experiment demonstrated that the trinuclear compound is an excellent precursor for NiFe〓O〓 nanoparticle.Ⅲ.

实验显示这种三核化合物〓是一种很好的制备NiFe〓O〓纳米颗粒的前提物。Ⅲ。

The small size pure NiFe〓O〓 nanocrystals were successfully synthesized by solvothermal reaction with 〓 as precursor.

以〓为前体物，利用溶剂热反应成功制备了纯的NiFe〓O〓纳米晶粒。

The effect of the size of alumionphosphate precursor, ammonia flow and nitridation temperature on preparation of AlPON were investigated.

考察了磷酸铝颗粒度、氨流量和氮化温度对氮化磷酸铝制备的影响。

Nornicotine is produced by the N-demethylation of nicotine during the post-harvest treatment of tobacco leaves.Nornicotine in tobacco serves as the precursor in synthesis of the well-characterized carcinogen N'-nitrosonornicotine, one of the tobacco-specific nitrosamines, and consequently damages the health of tobacco smokers and passive smokers.

烟叶的采收后处理和加工过程中，大量的尼古丁经去甲基化作用生成了去甲基尼古丁，后者是烟草特有的亚硝胺类(tobacco-specific nitrosamines， TSNAs)致癌物——亚硝基去甲基尼古丁(nitrosonornicotine， NNN)的前体，与人类健康息息相关。

The aim of this paper is to synthesis the flavor precursor of olefine aldehyde which can be used in tobacco flavoring.

本文主要研究缩醛类烟用香料前体化合物，以解决普通烟用香精由于易挥发而造成卷烟品质不稳定的问题。

Thus, in order to attain acetal can be used as precursor of its matrix olefine aldehyde, 2-undecental glycol acetal was synthesized, and the corresponding optimum reaction conditions as: 2-undecental 0.2mol, glycol 0.3mol, cyclohexane as solvent, catalysed by vitamin C, the optium reaction time was 6h, its reaction yield could reach over 77.25%.

为了进一步探求效果更理想的前体化合物，本文继续合成了2-十一烯醛乙二醇缩醛，通过单因素优化实验得到最佳反应条件为：环己烷作溶剂，VC作催化剂，用量0.42%，醛醇物质的量之比0.2：0.3，反应时间6h，此条件下产品收率达77.25%。

Silica sol without ethanol was prepared with tetraethyl orthosilicate as precursor.

以硅酸乙酯为水解前驱体，制备了有机硅水溶胶体系。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。