成华区治疗不孕不育多少钱
时间:2019年09月22日 16:05:24

Firefighters use water to battle a towering inferno.消防员用水来扑灭熊熊燃烧的大火,You might wonder if water could also stifle an erupting volcano.你或许想知道水是否也可以用来扑灭喷发的火山。Actually, this experiment happens every timea volcano erupts at the bottom of the ocean.事实上,每次海底火山喷发就是对此进行的一个实验。What happens when a volcano erupts underwater?当海底火山喷发时,都发生了什么呢?Well find it out on todays moment of science.我们今天就跟随科学一刻栏目一起探个究竟吧。Most of the worlds volcanic action happens an average of eight thousand five hundred feetunderwater.世界上大多数的火山活动都发生在海平面以下平均8500英尺的地方。Deep beneath the waves there are an estimated one million volcanos.在海底大约有一百万座火山。As with land volcanos, molten lava pushes up from beneath the sea floor at thousands of degrees Fahrenheit.至于地面上的火山,就是由华氏几千度的炽热的岩浆从海底向上冲出而成。Ocean water cant “put out” the volcano the way firefighters put out a fire,海水并不能像消防员灭火一样扑灭火山,but it does have aprofound effect on what happens to the lava once its out of the ground.但是当岩浆冲出地面时,它确实能起到不小的作用。The biggest difference between undersea and land volcanos has nothing to do with waters wetness, but with its pressure.扑灭海底火山和地面的火山最大的不同在于水的压力,与水的湿度并没有关系。At these depths, the water pressure can be two hundred and fifty times more powerful than air pressure at the Earths surface.在这样的深度,水压可以是地面上空气压力的250多倍。This prevents bubbles from forming in the lava, eliminating the likelihood of an explosive eruption like some land eruptions are.压力可以阻止岩浆中形成气泡,这也就消除了地面火山爆炸性喷发的可能性。Instead, lava squeezes out of the ground like tooth paste out of a tube, forming glassy rock formations that look like long, stacked pillows.相反,岩浆就像牙膏挤出管子那样挤出地面,形成一道道玻璃般的岩层,看起来就想是一条长长的堆叠的枕头。The pressure is so high that steam never even forms where lava touches water.压力是如此巨大,以至于这些岩石接触到海水时连水蒸汽都还无法形成。You could be in a boat over a giant, erupting volcano, and never even know it was there.因此,你或许就曾经驾船行驶在一个巨大的喷发的火山上而丝毫没有察觉。So,you cant put out a volcano with water.所以,用水不可能扑灭火山。But on our next program, well find out whathappened to a town that tried to do this anyway-and in a way succeeded!但是在我们下一期的节目中我们将会告诉您一个镇子曾经试图这样做,而且从某种程度上来说,他们成功了! 201405/294998

Science and technology科学技术Cancer and the microbiome癌症和微生物组A punch in the gut肠道里的元凶How microbes promote liver cancer in the overweight微生物如何诱发胖人的肝癌OBESITY brings problems—notably heart disease, diabetes and cancer.肥胖产生了问题―尤其是心脏病、糖尿病和癌症。It is not hard to understand its connection with heart disease and diabetes: excess fat clogs arteries and messes around with the metabolism.肥胖与心脏病、肥胖与糖尿病的联系不难理解:多余脂肪堵塞血管,使新陈代谢紊乱。Its link with cancer is less intuitive.但是肥胖与癌症的联系凭直觉就不能理解了。Shin Yoshimoto of the Japanese Foundation for Cancer Research, in Tokyo, and his colleagues suspect this is at least partly because researchers have been looking for that link in the wrong place.位于东京的日本癌症研究基金会的Shin Yoshimoto以及他的同事怀疑,这主要是因为研究人员的研究角度错误。Most work in the field is focused on the cells of the human body.此领域的多数工作只是集中在人身细胞的研究。But researchers should, Dr Yoshimoto believes, be at least as interested in the cells of the microbiome, the collection of 100 trillion bacteria that live in the gut.Shin Yoshimoto认为,研究人员应当留心微生物组,这群生活在肠道的100万亿个细菌群。Mostly, the microbiome is beneficial.微生物组中的大多数都是有益的。It helps with digestion and enables people to extract a lot more calories from their food than would otherwise be possible.它们帮助消化,让人体从食物中分离出更多的能量。Research over the past few years, however, has implicated it in diseases from atherosclerosis to asthma to autism.然而,近几年的研究工作认为,微生物组是造成动脉硬化或孤独症等的病因。Dr Yoshimoto and his colleagues would like to add liver cancer to that list.但是,Yoshimoto以及他的同事则认为微生物组也是肝癌的病因。Their paper making this accusation is published in this weeksNature, and it is a careful, step-by-step analysis of the matter.他们的论文指出指控,发表在本周的《自然》杂志上。本篇文章进行了仔细、逐步的分析。They start from the facts that fat animals have different gut bacteria from thin ones; that some bacteria produce inflammatory molecules as part of their metabolism; and that inflammation promotes cancer.文章开始便列举了事实,肥胖动物的肠道细菌与瘦的不同;某些细菌在新陈代谢过程中产生一种能引起炎症的分子;炎症诱发癌症。They began their experiments by feeding laboratory mice a fatty diet, to make them obese.他们通过实验小鼠进行实验,喂养高脂肪食物,让它们长胖。Such mice, they found, are no more likely to develop cancer than those fed an abstemious diet.他们发现,吃了脂肪含量高的小鼠患癌症的机率不高于饮食有度的小鼠。Obesity alone, then, does not seem to cause tumours. But it might still promote them.因此,单独肥胖一项因素不会引起肿瘤,但是仍然会诱发肿瘤。Their next experiment therefore started by giving the mice a carcinogen known to trigger tumour formation throughout the body.因此,他们下一步的实验就是喂养小鼠能在全身形成肿瘤的致癌物质。One group was then fed standard fare while another got the high-fat diet.一组实验小鼠喂养标准食物,另一组喂养高脂肪食物。After 30 weeks, just 5% of the slim group had developed tumours, not in the liver but in the lungs.30个星期后,体形瘦削的那组只有5%患有肿瘤,不是在肝脏,而是在肺部。In the obese group, every animal had developed liver cancer.体形肥胖的那组,每只小鼠都患上了肝癌。To understand how this happened, the researchers began with the tumours and worked backwards.要了解其中的原因,研究人员先从肿瘤入手,采用了反正法。First, they found that the cancerous liver cells in their mice were generally accompanied by cells that had the symptoms of old age.首先,他们发现,实验小鼠中癌化的肝脏细胞周围的细胞出现了老龄化的症状。Such cells also emit chemical signals which promote inflammation, and thus encourage tumours.这些老化细胞会释放出引发炎症的化学信号,并进一步诱发肿瘤。The researchers suspected that these cells were being made senescent by something produced by gut bacteria.研究人员怀疑,细胞出现老化是由肠道细菌产生的某些物质所致。That suspicion was confirmed when they served some of their mice a cocktail of four antibiotics, to prune the animals microbiomes.研究人员混合了四种抗生素,喂养小鼠时,减少小鼠体内的微生物群。This treatment lowered the number of senescent and cancerous cells, suggesting the microbes were indeed to blame for promoting cancer.此时,他们的怀疑得到了实。这种喂养方法减少了老化和癌化细胞的数量,表明微生物确实是诱发癌症的因素。Dr Yoshimoto and his team then started to focus on which bacteria were causing the problem.接下来,Yoshimoto和他和团队开始研究是何种微生物导致问题。First, they discovered they could get the same cancer-suppressing effect using just vancomycin, an antibiotic that kills only “Gram-positive” bacteria.首先,他们发现,用专杀“革兰氏阳性”细菌的抗生素万古霉素进行实验,也能取得相同的抑癌效果。They also observed, as prior research had suggested, that a fatty diet raised levels of a chemical called deoxycholic acid and that antibiotics lowered it.同时,他们发现,高脂肪饮食会提升化学物质脱氧胆酸的水平,万古霉素会使其降低。Previous research had demonstrated too that DCA damages DNA in a way that promotes senescence.先前的研究也发现,DCA会以一种诱发衰老的方式破坏DNA。Dr Yoshimoto showed that lowering DCA levels in mice did indeed reduce the development of liver cancer.Yoshimoto让人们看到,降低实验小鼠体内DCA的水平确实会减少诱发肝癌的机率。Certain types of gut bacteria, including strains of Clostridium, are known to burp out DCA.某些肠道细菌,包括梭状芽胞杆菌菌株,研究人员进行进一步的工作,包括研究小鼠粪便。And further detective work, including examination of the mices faeces, revealed higher levels of a strain of Clostridium called OUT-1105 in the fat mice than in the thin ones.他们研究发现,肥胖的小鼠粪便中OUT-1105这种梭状芽胞杆菌的水平要高于瘦削小鼠。This strain, Dr Yoshimoto thinks, is the most likely culprit.Yoshimoto认为,这种梭菌很有可能就是罪魁祸首。There is, then, a chain of causation leading from the gut to the liver that promotes tumours in obese mice.之后,他们又发现了一连串的因果现象,说明了肥胖小鼠体内从大肠到肝脏诱发肿瘤的成因。And the chances are good that something similar pertains in Homo sapiens.这提供了好机会,因为这个过程与人体内的过程相似,Humans are not mice, of course.虽然人不是老鼠,But the two species microbiomes often do behave in the same way.但两者的运行机制还是相似的。If cancer does end up being added to the growing list of problems which an upset microbiome can cause, that may stimulate research into ways of tweaking it to stop it causing disease.人体内的微生物组令人烦恼,因为它会导致一些问题,而且由它导致的问题还在不断增加。假如由它导致的癌症防止不了,那么这就会刺激研究对微生物组进行调整,地防止产生疾病。It will also, once again, emphasise the microbiomes role, for both good and ill, as an adjunct part of the human body在此需要再一次地强调微生物组的作用,不论好与坏,毕竟它们都是人体的附属部分 /201311/263730

Airbnb versus hotels租房网VS旅馆Room for all, for now人人有房,就是现在But there are signs that the sharing site is starting to threaten budget hotels有信号显示住房分享网站开始威胁快捷酒店EVEN as they lobby regulators to crack down on residential sharing services, hoteliers play down the threat such companies pose to their industry. The top brass at the Marriott, Four Seasons and Hilton chains have all said that these firms do not compete for their core market of accommodating high-end and business travellers; a vice-president of The Ritz-Carlton group recently claimed she had not even heard of Airbnb. And Airbnb itself agrees, arguing that it does not displace existing lodging but is creating new demand. “Im optimistic that there isnt going to be a war” with hotels, Brian Chesky, its boss, said in January.尽管旅店老板正游说监管者取缔住房分享务,但他们仍淡化这类公司给其行业带来的威胁。万豪、四季、希尔顿的高管们说这类公司并没有在他们的核心市场展开竞争;丽嘉副总裁最近表示从来没听过Airbnb。Airbnb自身也这么认为,声称其业务并没有取代现存旅馆而是创造了新需求。一月,Airbnb老板布莱恩说:“我保持乐观态度,将不会和旅馆发生正面冲突。”A recent study seems to confirm that, for now at least, Airbnb is only nibbling at the hotel industrys lunch rather than eating it whole. A team at Boston University examined hotel revenues in Texas, where Airbnb has grown much faster in some cities . They could not find a significant influence from Airbnb on business and luxury hotels. But in places where it has established a presence, it cut the revenues of budget hotels by 5% in the two years to December 2013.最近一项研究似乎实了这一观点,至少就目前看来,Airbnb只是吃掉了这个产业的一小部分而不是一口全吃掉。波士顿大学的一个小组调查了德州酒店的收入情况,在这个州的某些城市,Airbnb的增长快于该州其他城市。他们没有发现Airbnb对商务酒店和豪华酒店的明显影响。但在某些发展较好的地方,Airbnb在截止2013年12月的两年内蚕食了快捷酒店5%的收入。If Airbnb were to keep growing at its current rate—its listings are doubling every year—the Texas study suggests that by 2016 the dent in budget hotels takings will be 10%. With their high fixed costs, that could push many of them into the red. Of course, Airbnb may hit the limits of either supply or demand before then, but smaller hotels are aly blaming it for their woes. “I see a direct correlation between our revenues going down and [Airbnbs] going up,” says Vijay Dandapani, the president of Apple Core Hotels in New York. “We had continued growth until Airbnb.” The financing round that Airbnb has just closed, valuing it at more than all but the four largest global hotel groups, suggests that investors agree.德州的研究表明,如果Airbnb按目前每年翻倍的增长速度发展,在2016年将会削减快捷酒店10%的份额。因快捷酒店较高的固定成本,这将直接导致很对酒店出现赤字。当然,Airbnb也会遇到自身供给和需求的限制,但小旅馆们早就将自己的古难归咎于Airbnb。纽约苹果核酒店管理公司总裁维贾伊说:“我看到了我们酒店收入下滑和Airbnb收入增长的直接联系,我们本该继续增长的,直到Airbnb开始抢夺市场份额。”Airbnb最新一轮融资刚刚结束,投资者相信其价值仅次于四大国际酒店管理集团。Moreover, Airbnb is beginning to make inroads into business travel. Ever more companies are letting staff book their own itineraries, and giving them incentives to be thrifty. Google sets a budget for each trip, and employees who underspend them get credits they can donate to charity or use for future perks like flight upgrades.此外,Airbnb开始进军商务旅行市场。更多的公司开始让员工自己定行程,给他们节约的激励。谷歌给每一个行程都设预算,员工节约下来的钱可以捐给慈善机构,也可以留下当做例如飞机升舱一类的未来福利。Concur, a travel- and expense-management firm, has seen its corporate clients Airbnb bookings grow from a rounding error at the start of 2012 to more than 1m so far this year. Much of this comes from groups looking for flats with multiple bedrooms and shared workspace. If Airbnb can integrate with online travel agencies such as Expedia and increase the share of its hosts that provide instant booking confirmation, business hotels may find themselves with a surprisingly unignorable competitor.一家旅行费用管理公司Concur见了Airbnb的增长,2012年初其客户在Airbnb的业务量微乎其微,但今年现阶段其业务量已经超过100万美元。其中大部分业务来自寻找带多间卧室并共享工作区域这类公寓的顾客。如果Airbnb能整合像Expedia这样的网上旅行社,并增加能提供即时预订确认的主机的共享程度,商务酒店或许会惊奇地发现一个不可动摇的强大竞争者。 /201405/294178

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


文章编辑: 快问社区
>>图片新闻