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深圳罗湖人民妇幼保健医院祛眼袋多少钱好医解答

2017年12月19日 04:10:53 | 作者:QQ中文 | 来源:新华社
Most people assume that roosters are programmed to crow at the first sign of sunlight to announce the dawning of a new day, or some such romantic notion.大多数人都会认为每当第一缕阳光照耀大地,公鸡就会按规律打鸣表示崭新一天的开始。除此之外还有很多关于此浪漫的传说。Like all birds, roosters call in a daily cycle determined by circadian rhythms.和其他鸟类一样,公鸡每天打鸣的习惯是由生理节律所决定。That is, a roosters internal clock allows it to anticipate the sunrise and prepare for another exciting day of looking for food.公鸡的生物钟让它期待日出,以此为契机开始新一天的觅食。But why must roosters crow as they prepare to start their day, and why do some roosters sound off before dawn?但是,为什么公鸡会打鸣,而且这一时间点是在黎明前呢?Roosters are territorial creatures and dont much like other roosters trespassing on their land.公鸡是具有领地意识的动物,决不许其它公鸡侵犯自己的领地。They crow in order to establish their domain and warn other roosters to stay away or prepare to brawl.为了守护自己的地盘,警告其它公鸡远离进而避免争斗。And because their internal clocks are sometimes set a bit early, some roosters begin crowing well before sunrise.而且公鸡的生物钟有时候设置得早一些,所以有些公鸡是在日出前打鸣。201312/268617

Science and technology科学技术Cell biology细胞生物学On your marks...各就各位…The first cell race in history may further knowledge about how cancers sp历史上的首次细胞赛跑,可能增进了解有关癌症如何扩散的知识IT WILL not come with garden parties, large hats or eager bookies.这次比赛将不会与花园招待会,高职位或急切的赌注登记经纪人一起到来。And the contestants will be too small to see with the naked eye.并且,参赛者也会因过于细小而肉眼无法看到。But the World Cell Race, due to begin at the end of this month, will be the sporting event of the year for cell biologists.但是预计将于本月底举行的世界细胞竞赛将是今年细胞生物学家的体育盛会。The idea of the race is simple.竞赛的想法很简单。Labs from around the world send the runners—whatever sort of mammalian cell they think will do well—to one of six testing sites.世界各地的实验室将把他们的参赛者—无论哪一种他们认为将表现不错的哺乳动物细胞—送到6个测试点之一。There, the cells will be injected onto plates striped with tracks of a chemical they like to adhere to.在这些测试点,细胞将被注入他们喜欢粘附的一种化学制品跑道的条纹板里。Progress will be watched through a microscope, by time-lapse photography. And whichever cell covers a tenth of a millimetre fastest will be declared the winner.显微镜通过延时摄影可以观察到它们的进展情况。然后无论哪种细胞,只要先跑过十分之一毫米的跑道就将被宣布为赢家。The field is wide open.该领域的大门敞开着。Unlike horse-racing, the contest is not restricted to thoroughbreds.不像赛马,该竞赛并不局限于纯种动物。In fact the organisers, Matthieu Piel, Ana-Maria Lennon-Dumenil and Manuel Thery, who all work in France, are particularly encouraging the entry of genetically modified cells,事实上,该次竞赛的组织者—都在法国工作的马修?彼尔, 安娜 - 玛丽?列侬-邓内尔和曼奴埃尔? 西里特别鼓励转基因细胞的参选,as these are likely to be the most successful—and most instructive—competitors.因为这些细胞很可能是最成功的—而且是最有意义的—竞争者。That is because a lot of research on cell movement uses genetic modification to silence or amplify genes thought to be involved in the process.这是因为很多细胞运动的研究使用遗传改造来抑制或增强基因表达。这些改造过的基因被认为参与了这个过程。Many of these genes have been found by looking at cancerous cells.许多基因可以通过观察癌细胞找到。Metastatic tumour cells—those which have sp from the site of the original tumour—migrate faster than other cells.转移性肿瘤细胞—那些已从原发部位扩散开的细胞—比别的细胞移动得要快。If the genes that cause this mobility could be turned off, it would slow a cancers sp.如果导致这种流动性的基因能被关掉,这将减缓癌症的扩散速度。More positively, cell migration is the driving force of embryo development and is, in adults, essential to the immune response and to the healing of wounds.更加肯定的是,细胞迁移是胚胎发育的原动力,而且对成年人来讲,细胞迁移对免疫反应以及伤口愈合非常重要。Understanding cell movement, then, is important.于是,理解细胞运动非常重要。Hence the idea of the race, which Dr Piel and Dr Lennon-Dumenil and Dr Thery came up with at last years meeting of the American Society for Cell Biology.因此,彼尔士和列侬-邓内尔和西里士在去年的美国细胞生物学学会的会议上提出这次竞赛的想法。So far their competition has attracted 30 entrants.到目前为止,他们的竞争已经吸引了30名参赛者。The heats will take place throughout August.整个八月份都将是预赛。Only at the end of the month will the s be analysed to name the winners.只有八月底才有视频来分析决定赢家。The organisers say they are also considering giving a prize to the slowest cell, since lethargic cells would be a boon for cancer therapy.组织者说他们也正在考虑给最慢的细胞一个奖项,因为呆滞的细胞对癌症治疗来说将是非常有用的。For cell biologists it should be an exciting contest.对细胞生物学家来说,这次竞赛应该是一次令人兴奋的比赛。But a word of advice to sports fans: maybe just catch the highlights.但是我要给体育爱好者提个建议:或许恰好碰上最重要的时刻了。 /201305/238031

Look at various parts of the sky on a clear day and you will see that it is not a uniform blue.抬头仰望天空,你会发现在晴朗的日子里,天空并不会呈现出统一的蓝色。Even if the sky is deep blue when you look straight up, near the horizon it is lighter.即使你头顶上正对的这片天是深蓝色的,靠近地平线处的也会相对较浅一些。This is partly due to pollution, but even in the cleanest air the sky is lighter near the horizon due to the effect of earths atmosphere on sunlight.部分原因要归咎于污染,但是就算是在最干净的空气中,贴近地平线处的天空颜色也会比较浅,这是由于地球大气层对阳光的影响。When the rays of sunlight enter the atmosphere,the atmosphere tends to deflect the light from its straight-line path from the sun to the earth, and sp it around the sky, a process that is called scattering.当太阳光线进入到大气层时,大气层会使阳光直行进入的路线产生偏离,并使光线散布于天空中,这个过程就叫做散射。If all the colors were sp equally the sky would look white, since all of the colors of light combined make white light.如果所有颜色的光线都均匀分散开来,那么天空看上去就会是白色的,因为所有颜色的光线组合起来就是白光。But the atmosphere does not sp all colors equally in all parts of the sky, and that is why the sky is not a uniform color.但是大气层不会把所有颜色的光线均匀分布在整个天空中,这就是为什么天空看上去不是统一的颜色的原因。The color that is most ily sp is blue.最容易发生散射的是蓝色的光。So when we look up on a clear day we see blue sky,since the sunlight has had to pass through the least atmosphere, and fewer of the other colors of light have been sp.由于阳光能够穿透最薄的大气层,并且只有少量颜色的光会发生散射,因此在晴朗的天气里,我们看到天空呈现出的就是蓝色。However, closer to the horizon the sunlight must pass through more of the atmosphere before it reaches our eyes.然而,在越靠近地平线的地方,阳光在进入我们的视野之前必须要穿过的大气层也就越厚。This gives the rays of other colors of light a chance to be sp so that the light reaching our eyes is more a mixture of all the colors and therefore appears lighter.这就为其他颜色的光发生散射提供了机会。这样一来,进入我们视线的阳光就更像是所有颜色的光的混合体,因此会看上去会比较浅一些。201404/289238

Science and technology科学技术Arthritis and botulinum toxin关节炎与肉毒杆菌毒素Something to celebrate值得庆贺Botulinum toxin may help relieve chronic pain肉毒杆菌毒素也许能够帮助缓解慢性疾病的痛苦An inflammatory problem炎症的痛楚ARTHRITIS is the bane of millions of lives.关节炎是数百万人的噩梦。Though it comes in many forms, their common theme is inflammation of the tissues around a joint in the skeleton.关节炎有多种形式,但它们共同的特征是关节处组织的炎症反应。Treatment is merely palliative: anti-inflammatory drugs, painkillers or both.对此的治疗手段往往是治标不治本:消炎药,止痛药,或者两者同时用。But a piece of research published this week in Biochemistry, by Edwin Chapman of the University of Wisconsin and his colleagues, offers arthritis sufferers hope from a strange quarter: botulinum toxin.但是由威斯康辛大学埃德文·查普曼士以及他的同事们在本周生物化学杂志上的发表的一项研究,为关节炎患者提供了希望:肉毒杆菌毒素。This toxin is one of the most dangerous substances on earth.这种毒素是地球上最危险的物质之一,It is made by a bacterium called Clostridium botulinum.它是由一种叫肉毒杆菌的细菌合成。Even a small amount is enough to kill a healthy adult.仅仅很小的量就足以杀死一个健康成年人。The toxin molecules attach themselves to a protein called synaptotagmin, which is found on the surface membranes of nerve cells at their junctions with muscle cells.这种毒素能结合到一种叫做synaptotagmin的蛋白上,SYT则位于神经肌肉接头处神经细胞的细胞膜表面。Thence they are ingested into the cell, where they disable another protein, SNAP-25, the role of which is to help release a chemical messenger called acetylcholine.然后这种毒素被吞入细胞内部,进而让另外一个叫SNAP-25的蛋白失活,SNAP-25的作用是帮助一种叫乙酰胆碱的化学信使的释放。This messenger’s job is to tell muscle cells to contract. Without that signal, muscles stops working. If this happens all over the body, death is rapid.这种化学信使的作用则是让肌肉细胞进行收缩。没有这种信号的话,肌肉便停止工作了。如果全身都发生这样的情况,死亡便接踵而来。Inject the toxin locally, though, and you can do some good.然而局部注射肉毒素还能带来好处。It wipes away frown lines and other wrinkles, which are caused by overstimulated muscles,它能抚平额头和其他部位的皱纹,这些皱纹恰恰是因为肌肉被过度刺激引起的。thus allowing ageing celebs to appear on the covers of gossip magazines without embarrassment.它使得那些上了年纪的名流们毫无尴尬的出现在街头杂志的封面。More seriously, it is used to treat disorders ranging from headaches to muscle spasms.它更为严肃的用途是治疗各种生理紊乱,包括从头痛到肌肉痉挛。It only works, however, in cells that have synaptotagmin on their surfaces.然而,它仅仅能在那些表面具有SYT蛋白的细胞中起作用,Which is where Dr Chapman comes in.这正是查普曼士的切入点。Inflammation is also caused by chemical signalling.炎症反应同样是由化学信号引起的。Cells called macrophages summon all sorts of others to an injury, to try to repair it.巨噬细胞召集其他免疫细胞到达受伤处,并试图修复伤害。If repair cannot be effected, though, the signalling never stops.但如果修复不起作用,则这些信号就不会停止。The swelling causes pain, and the patient suffers.肿痛造成痛苦,而病人只能忍受。But macrophage signalling also involves SNAP-25, so Dr Chapman thinks he can use botulinum toxin to shut the cells up.但是巨噬细胞的信号通路中也包括SNAP-25,因此查普曼士想,他能够用肉毒素来关闭这些免疫细胞。The problem is that macrophages have no synaptotagmin on their surfaces.问题在于,巨噬细胞的表面并没有SYT蛋白,They do, though, have other proteins, called Fc receptors.他们表面有的是另外一种被称为Fc受体的蛋白。What is needed is a way to get toxin molecules to attach themselves to Fc receptors.现在只需要找到一个办法,让肉毒素结合到Fc受体上去,And this is what Dr Chapman thinks he has managed.而查普曼士认为,他办到了这一点。His trick is to link each molecule to an antibody.他的绝招是将每个分子与抗体连接起来。An antibody is a protein that binds to a hostile invading organism.抗体是一种能结合入侵有机体的分子,If this does not kill the invader outright, then it acts as a flag for the bug in question to be eaten by a macrophage.如果抗体不能马上杀死入侵者,则它将作为入侵者的一个标记,使得它们有可能被巨噬细胞所吞噬,That happens when the antibody that is attached to the invader also attaches itself to an Fc-receptor molecule.这个过程只有当结合在入侵者上的抗体同时也能和Fc受体分子结合时才会发生,This done, the invader is ingested.而这个步骤一完成,则入侵者就被吞噬了。Dr Chapman’s plan was to use this mechanism to get macrophages to eat toxin molecules.查普曼士的计划是,利用这个机制,让巨噬细胞把肉毒素吞进去,Once inside, they would disable SNAP-25 and thus stop the release of signalling molecules in the way they do in nerve cells.而进入细胞之后,它就能使SNAP-25失去活性,从而像在神经细胞中一样,阻止信号分子的释放。The result, the theory goes, would be an end to the chronic inflammation that arthritis causes, and thus to the chronic pain.如果这个理论可行,那么由关节炎所导致的慢性炎症将被终结,同时被终结的,还有长期以来的痛苦。The first stage works.第一步看起来是可行的。The toxin/antibody complex successfully gloms onto the macrophages.肉毒素与抗体的复合物成功地黏附上巨噬细胞,The toxin does get inside them.肉毒素确实进入了巨噬细胞内部,And the cells do stop signalling.这些细胞也的确中止了信号通路。It is a long way from there to a treatment,从这一步到治疗仍有很长的路要走,but Dr Chapman has made the trick work in mice as well as Petri dishes.但是查普曼士已经用这个方法在培养皿的细胞中和在老鼠身上获得了成功。Many more animal trials will be needed before it can be tested on people.在人体上进行测试前,还需要完成更多的动物实验,But for those who suffer the chronic pain of arthritis, it is a hopeful start.但是对于那些正在长期忍受关节炎痛苦的人们来说,这是一个充满希望的开始。 点击此处下载本期经济学人讲解PDF与音频字幕 /201306/245355

Science and technology科学技术The future technology of the past六十年代的未来技术Thunderbirds are gone远去的雷鸟号A British defence firm opens its archives to reveal flights of fancy that never flew英国防务公司公开档案,从未实现的奇思妙想重见天日READERS of a certain age may remember Gerry and Sylvia Andersons sci-fi puppet shows—Supercar, Fireball XL5, Stingray, Thunderbirds and Captain Scarlet—filmed, as the Andersons put it, in Supermarionation.上了一定年纪的读者或许会记得盖瑞·安德森和西尔维娅·安德森的科幻木偶剧-《飞天神车》、《雷霆机五号》、《霹雳艇》、《雷鸟特攻队》以及《超空人》,剧集均由安德森夫妇所称的超级木偶出演。Those who remember Captain Scarlet in particular may find one of the pictures here eerily familiar.特别是那些还记得《超空人》的读者会发现上面的照片里有一张似曾相识。English Electrics Fighter Jet Take-Off Platform, a flying airfield, is not quite the Cloudbase from which the immortal captain operated.英国电气的空中机场-战斗机起飞平台与该剧中永远的队长操控的云霄基地不太像。But it was intended, like its fictional counterpart, to launch and receive planes while itself airborne.但就像云霄基地一样,其目的是要在空中发射和接收飞机。It would have taken off and landed vertically in, say, a jungle clearing otherwise inaccessible to the aircraft piggybacking on it.它要在一块从林里的空地上垂直起降,否则其所载的飞机无法起落。English Electric was one of the firms merged into what eventually became BAE Systems, and BAE has recently been through its archives and publicised some of the projects dreamed up in the glory days of the 1960s, when designers imaginations were allowed to run riot with little consideration of practicality or budget. MUSTARD, for example, was designed by the British Aircraft Corporation.英国电气是最终被合并为英国航宇系统公司的众多公司中的一员,BAE最近完成了其档案整理工作,并公开了一些在上世纪六十年代的辉煌岁月中构想出来的项目,其时,设计人员的想象力可以天马行空,无需考虑可行性或者预算。例如,MUSTARD是由英国飞机公司(BAC)设计的。It could pass for something out of Fireball XL5 or Supercar—though it also resembles Virgin Galactics SpaceShipTwo which will, Virgin hopes, soon be taking paying passengers to the edge of space.可以认为其构想来自于《雷霆机五号》或《飞天神车》----不过它也有点像维珍公司的太空船二号,维珍公司希望其很快便能载着付费乘客到达太空的边缘。It would have been a three-stage space-plane, though only one stage would have made it into orbit.太空船二号会是一艘三级航天飞船,尽管只需一级便能将其送入轨道。The other two were reusable boosters.其余的两级为可重复使用的助推器。An Anderson version of the Jumping Jeep, also by BAC, might easily have emerged from the pod carried by Thunderbird Two on one of its missions for International Rescue.在雷鸟二号执行国际援助组织的任务时,一辆安德森版的跳跃吉普-也出自BAC-从雷鸟二号携带的隔舱中脱离时或许比较简单。Continuing the vertical-take-off theme, the Jeep would have had 12 fans whose downdraft would have helped it over obstacles such as ditches.继续刚才垂直起飞的主题,这辆吉普有12个螺旋桨,其产生的向下气流能使吉普跨过壕沟等各种障碍。And Hawker Siddeleys Intercity Vertical-Lift Aircraft, intended as a passenger plane that could land in urban airports not much bigger than pocket handkerchiefs, looks like the sort of thing that would have whisked Lady Penelope Creighton-Ward, International Rescues London agent, from her penthouse in Mayfair to New York for a days shopping.霍克·希德利公司的城际垂直起降飞机是想成为一架可以在胸袋手帕那么大的市内机场中着陆的客机,就像那种能让潘妮洛普·克雷顿华德夫人从自己位于梅菲尔的阁楼一路飞驰到纽约去购物一整天的飞机。Sadly, none of these fantasies made it into metal.可悲的是,这些奇思妙想中没有一个成为现实。They remain as fictional as the Andersons puppet shows.它们就和安德森夫妇的木偶剧一样,只是停留在虚构层面。Too expensive. Or too noisy.要么费用太高,要么噪声太大,Or simply too silly.要么就只是想法太愚蠢。But that is the strange thing about the future.但这是关于未来的东西总是很怪。Nothing ages faster than yesterdays dreams of tomorrow.没有比昨天的明日梦更易老的东西了。 /201311/264384

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