向细胞的

Micro-computer monitors work inside the electron gun to emit electronic, through the acceleration of high-voltage electrode, adjust shooting at the screen, the screen of fluorescent material by high-speed electronic flow impact, resulting in X-ray, scientific evidence shows that more than 20 of each year only Guoqin dose of radiation, will constitute a harm to humans, operate microcomputer year will not be more than 0.3 Roentgen of exposure; even when engaged in computer work for 30 years, the cumulative exposure will not be sufficient to cause human injury lowest half, but during early pregnancy (the first 3 months) the fetus is in a cell division, organ differentiation sensitive period, or should be:(1) hours of work per week is not more than 20 hours (2) one meter away from the computer (3) wearing protective skirt (4) work completed Huanyi bath in order to reduce the electromagnetic radiation on the impact of the fetus.

微电脑显示器工作时，内部的电子枪发射出电子来，经过高压电极的加速，调整射向荧光屏，屏幕上的荧光物质受到高速电子流的撞击，产生X射线，科学论证表明，每年只有超过20论琴的剂量照射，才构成对人体的伤害、操作微机一年也不会超过0.3伦琴的照射量；即使从事微机工作30年，累积的照射量也不足以造成人体损伤最低值的一半，不过妊娠早期(头3个月)胎儿正处于细胞分裂，器官分化的敏感时期，还是应当：(1)每周工作不超过20小时(2)距电脑一米开外(3)穿防护裙(4)工作完毕洗澡换衣，以减少电磁辐射对胎儿的影响。

In chapter 5, the concept of zero-span tension known in papermaking area is for the first time introduce to wood science area to explore in-tree variation of longitudinal tensile strength of tracheids and its main influencing factors. In chapter 6, composite micromechanics and classic laminated theory are used to make a comprehensive and detailed analysis of the main influencing factors of mechanical properties of tracheids cell wall. Some experimental results acquired in the foregoing chapters are explained successfully. Results were summarized as follows: Mechanical characteristics of wood at micron scale: 1 At micron scale, the longitudinal mechanicai behavior of wood microtome section differs greatly from that of wood with normal size.

论文的第2章首先研究了微米尺度下木材的力学特性，为后面运用木材微切片拉伸技术奠定一定的理论基础；在第3章，首次考虑到了微米尺度下木材力学性质的尺寸效应，并运用木材微切片正常间距拉伸技术研究了管胞纵向弹性模量的株内变异规律；在第4章，首次利用纳米压痕技术中最新发展起来的连续刚度测量法直接在管胞细胞壁上进行纳米级的压痕实验，测量次生壁S〓层的纵横向弹性模量和硬度，从而把细胞壁力学的研究提高到一个更高的水平；在第5章，首次把造纸领域的零距拉伸技术引入木材科学研究领域，研究了管胞纵向抗拉强度的株内变异规律及其主要影响因素；第6章则运用复合材料细观力学的基本理论和经典层板理论对影响细胞壁力学性能的主要因素进行了全面而系统的分析，并为前几章的一些实验结果提供理论上的解释。

The result showed that, the body wall most outer layer cuticle assumesthe translucent porodine, the surrounding entire body wall; Close isconnected with the cuticle 表皮层 for 合胞体 the structure, inthe back, the abdomen and its two sides separately adds thick to inprominent Cheng Jizhuang, separately contains the back side,腹侧the nerve and compares to the developed back, the abdomen nerve; Themyo- position to the body wall most inner layer, has the muscle cellto arrange becomes; Between the body wall and the digestive tractcavity is a body cavity; Digestive tract for 肌质 structure, afterinference for roundworm's esophagus.

结果显示，体壁最外层的角质层呈半透明的胶状，包围整个体壁；与角质层紧密相连的表皮层为为合胞体构造，在背、腹及其两个侧面分别加厚向内突出成脊状，分别包含背侧、腹侧神经和相比对发达的背、腹神经；肌层位于体壁最内层，有肌细胞排列而成；体壁与消化道之间的空腔为体腔；消化道为肌质结构，经推断为蛔虫的食道。

Expanded MSCs were induced to differentiate into nerve cells withthree different treatment protocol in the prensent study . On the following day, the medium was replaced with preinduction medium consisting of DMEM, 20% FCS, and 10 ng/ml basic fibroblast growth factor. After 24 h, the preinduction medium was removed, the cells were washed twice with PBS, and neuronal induction medium containing DMEM supplemented with 2% DMSO and200 m bu-tylated hydroxyanisole was added. In later experiments, we used DMEM with 5 mM p - mercaptoethanol or sulfo - glycerine as an alternative neuronal induction medium for the same incubation.

将待诱导分化的MSCs按0.4x10~6／ml接种于事先放置有消毒盖玻片的六孔板内制备细胞爬片，分别采用三种不同的方法诱导第2代至10代的MSCs向神经细胞分化，即方法1先用含bFGF的培养基进行预诱导，之后再用含叔丁基对羟基茴香醚，和二甲亚砜的无血清培养基进行诱导；方法2和方法3用B-巯基乙醇和硫代甘油进行预诱导，然后不同浓度的上述物质进行正式诱导。

But ha also finds some fascinating, admirable, and maddening characters who have pursued the truth about extraterrestrial life: Cad Sagan, the brilliant astronomer who brought the cosmos to the masses; Dan Goldin the cantankerous head of NASA who still believes in the dream of the Space Age; Henry Harris, a former Las Vegas lounge singer who is assigned the job of figuring out how to get a spaceship to Alpha Centauri; and various and sundry ufologists, experiencers, spiritualists, and channelers for whom the aliens are an ever-present reality.

要想理性的来看待外星生物，首先我们必须搞清我们到底是谁，为什么存在，流淌在我们细胞中用了四十亿年才完成的进化史到底意味着什么。作者要向我们传达的信息是：能在这个充斥着岩石，气体和尘埃的宇宙中做有感知的人真棒---人是可以幻想的。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。