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"I've called it an epidemic in America because just about every American, including many teens, own cell phones and they think they can talk and drive and do it safely,and they can't."
VOA: standard.2010.06.24
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It can be very stressful especially because we don't get cell phone reception down there.
这可以使人很紧张，尤其是因为在地铁站我们的手机没信号。
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So, when the right signal is received, the right T-cell finds your host cell with a foreign virus in it, the first thing that happens is that this T-cell becomes activated and it starts reproducing, making more copies of itself.
所以 当接收到正确的信号,恰当的T细胞寻觅到,感染外源病毒的细胞时,首先发生的是,T细胞被激活并开始增殖,制造更多自身拷贝
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It can't enter cells because it's too big and it's too water soluble so it can't go through cell membranes.
它的分子太大了所以无法进入细胞,而且还是水溶性的,所以它也无法穿过细胞膜
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The answer is, "It's not like anything," where that doesn't mean there's something that it's like to be a cell phone, but different from being anything else.
答案就是，什么感觉都不像“,那不是说,作为手机真的有一种感觉，只是和作为其他东西的感觉。
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So this means we can code for it in DNA, you don't have to worry how am I going to get into the cell.
这意味着我们可以在DNA中编写它，你不用担心它怎么进到细胞里去。
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One of the most obvious things about a red blood cell is it doesn't have nucleus, it has no nucleus.
红细胞最为明显的不同就是,它是无核的,它没有细胞核
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Because of that you can't count on molecules moving rapidly over the size of a cell that's ten to 30 Microns in diameter.
因此不要对生物大分子能在,直径十到三十微米的,细胞里高速穿行抱有任何指望
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I've already mentioned many times that the lipid bilayer, the cell membrane, isn't just a lipid bilayer.
我已经讲过很多遍这个脂质双分子层了,细胞膜它不只是一个脂质双分子层
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Formaldehyde cross-links proteins, so, if you treated this virus with Formaldehyde, even it was able to enter a cell, it couldn't break down anymore.
甲醛使蛋白质发生交联反应,因此,如果你对病毒使用了甲醛,即使它可以侵入细胞,它也不能够再进行分解
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You could use cell culture, so you don't have to grow the virus naturally in animals.
你可以利用细胞培养技术,那你就不必在动物身上培养病毒
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This is a new concept, receptors don't have to be these molecules on cell surface, there can be receptors that exist in other places within the cell.
这是一个新概念,受体分子不一定只存在于细胞表面,它们也可以存在于细胞内其它地方
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Some small subsets do but most of the cells in your brain don't proliferate and that's because they get trapped at one portion of the cell cycle.
除了很小一部分以外大部分脑细胞不增殖,这是因为,它们停滞于细胞周期的某个阶段
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So, it doesn't need to bind to a receptor on the surface of the cell in order to work because the molecule can actually enter the cell directly.
所以无需与细胞表面受体相结合来起效,因为这些分子能直接进入细胞
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One way that that's done is by introducing genes into cancer cells, genes that aren't normally expressed in any mammalian cell, but that will cause the cancer cell to die.
已经成功应用的一种方法是,将基因导入癌细胞,而这种基因通常不在哺乳动物细胞中表达,但是可以导致癌细胞的死亡
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No. Cell phones don't have any experience at all.
不，手机本身没有任何体验。
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So, these are receptors, for example, that bind the ligand and then liberate an enzyme which promotes some sort of reaction inside the cell, often it's kinases but doesn't have to be.
例如,这里是受体,与配体相结合,激活一种酶,这种酶能够催化细胞内的某些反应,这些酶通常都是激酶,但不全是
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So cell culture production wasn't an option.
因此把细胞作为病毒培养基行不通
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Now, sodium and potassium don't ordinarily move across membranes, they're charged molecules, they can't dissolve, they can't permeate through a cell membrane, but they go through because there are channels that allow them to pass through in the membrane.
钠和钾通常是不能跨过细胞膜的,它们都是带电粒子,它们不能溶解在细胞膜中,不能渗透通过细胞膜,但它们之所以能通过细胞膜,全赖膜上离子通道的作用
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How is your immune system going to recognize that this virus is there causing bad results if it's living inside of a cell and doing all its business inside a cell where antibodies can't get to it?
你的免疫系统怎样才能识别,作恶多端的病毒呢,如果它隐藏在细胞中进行繁殖,而抗体又无法进入细胞,那该怎么办
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That's a lot of the literature of stem cells that you'll read about, taking a particular source of stem cell and nurturing it in such a way that it gains potentials that it didn't have necessarily when it was in the body, or exploiting those potentials that it wouldn't necessarily express.
现在你可以找到很多,有关干细胞的文献中讲到,提取一种特定来源的干细胞,通过特定的培养方法之后,它们会获得在体内不能获得的潜能,或者开拓一些在体内不能得到表达的潜能
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The main effector cells in cell mediated immunity, the cells that do the main business are called T-cells.
细胞免疫中的主要效应细胞,即发挥主要作用的细胞是T细胞
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The antigen has to be presented to helper T-cells, those helper T-cells have to stimulate a B-cell population to both proliferate and differentiate.
抗原需要被呈递给辅助性T细胞,这些辅助性T细胞需要激活B淋巴细胞,使其增殖和分化
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So if it's not a cell that's going through division you can't use a retrovirus to express the protein.
如果细胞不在分裂阶段,你就不能用逆转录病毒来表达某个蛋白
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You don't want to generate a lot of cells that just start killing every cell inside your body.
你可不会希望产生一大堆这样的细胞,在你体内大开杀戒
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If a cell membrane was indeed just a lipid bilayer, then glucose could never enter the cell because it can't permeate through cell membranes.
如果细胞膜只是一个脂质双分子层的话,葡萄糖就不可能进入细胞,因为它不能渗透过细胞膜
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Why don't bacteria need a distinct nucleus and that's necessary in a human cell?
为什么细菌不需要单独的细胞核,而对人类细胞则为必需
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Human cells don't have a cell wall but most bacteria do.
人类细胞没有细胞壁而大部分细菌有
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We've talked about one class of molecules, they're transporters that move molecules from inside to outside, or outside to in, that wouldn't ordinarily be transported through a cell membrane.
我们已经讲过一类这样的分子,它们是能够将分子从胞内运至胞外的载体,或者从胞外运至胞内,这个过程不是简单地穿过细胞膜
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So, it makes a binary decision, either I create an action potential or I don't, but that decision could be based on many inputs, not just on input from one cell.
所以 这里产生一个二选一的决策,就是产生动作电位亦或不产生,不过这个决定可能是,根据很多输入信号做出的,而不是仅凭单个细胞所传来的信号
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