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崇明县祛痣多少钱上海市仁济医院隆胸多少钱浦东新区人民中医院玻尿酸价格费用 Don: Hey Yaeuml;l, I was wondering–why dont we hear much about the moon anymore? 嘿,Yaeuml;l,我在想——为什么我们现在没什么跟月球相关的消息了呢?Yaeuml;l: Whadya mean, Don? Don,你是什么意思?D: Its just that back in the 1960s and 70s, sending astronauts to the moon was a big deal, but nobody talks much about it anymore. 早在二十世纪六七十年代的时候,送宇航员上月球是个天大的事儿,但却没什么人再谈论这件事儿。Y: Well, actually NASA is planning to send astronauts back to the moon. 事实上,NASA正计划送宇航员重返月球。D: Really? 真的吗?Y: Yep. And this time theres talk of building a lunar base where astronauts can stay for weeks and months at a time to conduct experiments in low gravity. 对呀。这次他们说要建立一个月球基地,宇航员一次可以停留几周或几个月在低重力的条件下进行实验。D: Cool. 很棒啊。Y: But there are a few kinks to work out–like what to do about moon dust. 但还存在几个问题要解决——比如说月球尘埃怎么办。D: Wait. Why is moon dust a problem? 等等。为什么月球尘埃会是个问题?Y: Well, for one thing, it has chemical properties that resemble fresh fractured quartz, which is pretty toxic. 嗯,一方面,它的化学性质,像断裂的石英,那是有剧毒的。And moon dust is clingy; it gets all over spacesuits and inside space capsules.而且月球尘埃很有依附性,太空太空舱里面都会有。Astronauts from the 60s and 70s used to complain that there was so much dust inside the capsule that they could smell it. 二十世纪六七十年代的宇航员们曾经抱怨,太空舱里面有太多的灰尘,甚至他们都能闻得到。D: So is the dust actually dangerous? What happens if it gets in the lungs? 那么灰尘对身体有害吗?如果它进入肺里会怎样?Y: Thats what scientists are studying now. 那就是科学家们现在正在研究的。One issue is that the moons weak gravity could allow dust particles to float around in an astronauts airway, which could let moon dust penetrate deeper into the lungs. 一个问题就是,月球的低重力会让尘埃粒子飘进宇航员的导气管,这可能让月球尘埃更深地穿透进人的肺部。D: Which increases the health risks.这就增加了健康风险。So what can astronauts do to breath in less dust? High-tech feather dusters? 那么怎么做才可以让宇航员吸入较少的粉尘?高科技的鸡毛掸子吗?Y: Funny. But its a good question–one that scientists are busy looking into before sending astronauts up there to set up house on our very dusty moon. 太逗了。不过这确实是个好问题。这是科学家们正在忙于调查的问题,要在将宇航员们送上太空造房生活之前解决的问题。201308/251148上海最好的整形医院

上海复旦大学附属华东医院激光祛太田痣多少钱But most significant of all, the jaguar has a tell-tale trademark. Instead of going for the neck or snout like most cats do, it kills with a crushing bite through the skull into the brain. This makes the jaguar prime suspect in this case. Even the glyptodonts defences had a fatal flaw. 但最重要的是,美洲虎有一个独特的特点,与大多数猫科动物不一样的是,美洲虎捕猎时不会直接撕咬猎物的颈部或者面部,它会在猎物的头骨上直接给予猎物大脑致命一击。这使美洲虎成为了这个头骨的“首要嫌疑凶手”。尽管雕齿兽的防卫有一个致命缺点。13,000 years ago, another very different kind of hunter reached this warm corner of the continent. Floridas springs have produced an unparalleled record of these first people, examples of their craftsmanship and hunting expertise, including razor-sharp flint spear points. 13000年前,另一批不同的猎人来到了这片大陆的角落。佛罗里达的泉水中记录了第一批人类无可比拟的技艺以及狩猎技巧,例如,带着锋利石头的箭头。The area was rich in flint for making weapons and in animals to hunt. And with the milder climate, these people probably had an easier life than their contemporaries further north. Small clues to their arrival have survived undamaged over 13,000 years—spear points, fishhooks and other glimpses of their daily life showing the versatility of these first inhabitants of the Sunshine State. 这片区域有着足够多的锋利岩石来制造武器,也有着足够多的猎物。当气温回暖后,这些人类的生活可能会比他们北方的同胞们更加舒适。13000年过后,还是能够发现他们来到过这里的痕迹——箭头,鱼钩。他们在这里生活的另一些痕迹表明,这些首批来到“阳光州”的人类技能多种多样。They hunted a wide range of ice age animals and Florida possesses a unique record of one such encounter. The skull of an extinct bison restored here was discovered in one of the rivers. Planted deep in the top of the skull was a flint spear point.这些人类捕杀过大多数的冰河时代动物,对此,佛罗里达拥有一个独特的据明这一事实。在这里保存着一只灭绝的北美野牛的头骨,它被发现于一条河流之中。在头骨的深处,有一个绑着锋利石头的箭头。英文文本来自普特英语,译文属未经许可不得转载.201307/250436上海抽脂哪里好 崇明县人民中医院激光去斑手术价格费用

上海交通大学医学院附属上海儿童医学中心激光去斑手术价格 Science and technology科学技术Dental X-rays牙科X光Little and not often, please请不要太频繁,一点就好Confirmation that dental X-rays can be bad for you已实牙科X光对你是有危害的If you are a suspicious type you may be disturbed by the fact that, despite reassurances of the safety of the procedure, dentists and their technicians, when administering X-rays, usually step out of the room while the deed is done.尽管牙科X光实施程序的安全已得到了实,牙医和技工们还是会在拍X光时离开房间。如果你是一个多疑的人,这样的事实可能会困扰你。Not only that, they often drape a lead-lined apron over your body to protect your vital organs. Well, all but one: your brain.不但如此,在拍X光时他们还经常用铅衬的围裙盖住你的身体以保护重要器官—但是是除了大脑以外的所有器官。A study by Elizabeth Claus, of Yale University, just published in Cancer, suggests your suspicions might be justified.耶鲁大学的伊丽莎白. 克劳斯医生的一项研究结果刚在癌症杂志上发表。此项研究表明你的怀疑可能并非杞人忧天。Dr Claus thinks she has identified, in those who have had dental X-rays often, a significant rise in the admittedly small risk of developing a brain tumour.克劳斯医认为她已发现那些经常拍牙科X光的病人得脑瘤的风险确实有显著升高。In rich countries, five men in every 200,000, and twice as many women, develop tumours called meningiomas that affect the membranes surrounding the brain.在富裕的国家里,每200,000人中就有5名男性得一种叫脑脊膜瘤的脑瘤,此瘤破坏脑膜,而且发病的女性人数是男性的两倍。Meningiomas account for a third of primary brain tumours.脑脊膜瘤的患者占原发性脑瘤患者的三分之一。Only about 2% of them are malignant, but non-malignant does not mean non-dangerous.只有2%的脑脊膜瘤是恶性的,但是非恶性并不代表没有危险。Even a benign meningioma can kill.即使是良性的脑脊膜瘤也会至死。Around 30% do so within five years of diagnosis. Symptoms can include seizures and blindness, and treatment may involve surgery, chemotherapy or, ironically, radiotherapy.大约30%的至死病例是发生在确诊后5年。这种脑瘤的症状包括:痉挛和失明,可以通过手术,化疗,或者用放射疗法来进行治疗。Ironically, because past research studying the after-effects of exposure to things like atom bombs and radiation treatments for cancer suggests the most important environmental risk factor for meningiomas is ionising radiation.讽刺的是,对人体暴露于类似原子弹辐射和癌症放射疗法的后果的研究显示,产生脑脊膜瘤的最主要的环境风险因素是离子辐射。These days, however, the main source of ionising radiation for most people is neither fallout from bombs nor radiotherapy; it is dental X-rays.然而,现今影响大多数人的离子辐射的主要源头既不是原子弹的辐射尘埃也不是放射疗法,而是牙科X光。Despite that, surprisingly little research has been done on those X-rays effects.尽管如此,令人惊讶的是几乎没有牙科X光对人类影响的研究。Dr Claus and her colleagues have tried to plug the gap.克劳斯医生和她的同事们已在努力填补这一空白。They studied 1,433 Americans who have had meningiomas and compared them with 1,350 others who have not.他们研究了1433名美国的脑脊膜瘤患者,并把他们与1350名非患者进行对比。These others were chosen to match the study groups age profile, sex ratio and dwelling place.这些被选择的非患者构成符合研究所需的年龄组成,性别比例和所在居住地。The researchers then inquired about both groups family, medical and dental histories.研究人员获取了这两组研究对象的家庭,病史,和牙病史的数据。In the case of their dental histories, participants were asked whether they generally had standard X-rays, known as bitewings, every year, or never had them, or fell somewhere in between.对于牙病史,参与者被问及他们是否通常每年接受常规的牙医X光,或是从没拍过,或是介于以上两者之间。They were also asked how often they had had panoramic X-rays—so-called panorexes—taken of their entire mouths, and whether they had ever had braces, the fitting of which often involves a panoramic X-ray.他们还被问及拍全颌x光—对整个口腔拍摄X光的经常性,以及是否做过牙齿整形—通常是会要求拍全颌x光。The researchers found that people who had had a meningioma were more than twice as likely as those who had not to have had at least one bitewing X-ray.研究发现患脑脊膜瘤的病人发病的可能性是那些没拍过咬翼片的人的两倍以上。And the more bitewings they had been given, the greater that likelihood was.拍咬翼片次数越多的人,可能性越大。Even more troubling was the finding that people who had been given a panorex when they were under ten had 4.9 times the normal risk of developing a meningioma.更让人担忧的发现是十岁以下拍过全颌x光的人患脑脊膜瘤的概率是正常风险值的4.9倍。To be fair, only 22 participants in the study had both had a panorex and developed such a tumour.公平地说,只有22名研究参与者拍过全颌x光并患有脑脊膜瘤。But according to Dr Claus, the panorex was not common when most of the people in the study had been children.但据克劳斯医生说,以前研究对象大部分是儿童,拍全颌x光的现象并不普遍。Nowadays, she says, before getting braces all the kids have it.如今,她说,在牙齿整形之前所有儿童都拍过全颌x光了。What these results mean in practice is debatable.以上研究发现的实际意义还是有争议的。The radiation dose from an individual dental X-ray, Dr Claus points out, has gone down by about half over the past 30 years or so.克劳斯医生指出,单次牙医X光的辐射剂量已在过去的30年降低到原来的一半左右。In addition, some dentists and orthodontists—though far from the majority—have turned to digital methods that expose patients to even lower levels. But others are using fancy new techniques like cone-beam computerised tomography which actually expose people to much higher levels of radiation.另外,一些牙科医生和整牙医师—虽然并不占多数,已转用电子手段,这就更大程度的降低了病人所受的辐射程度。Moreover, guidelines from the American Dental Association state that healthy adults should have a bitewing X-ray no more than once every two or three years, and that there is little reason to X-ray patients who do not have symptoms.此外,美国牙科协会的指南规定健康成年人每两到三年不应拍超过一次的咬翼片,并且没有理由给无病症的病人拍X光。These are policies which Dr Claus describes as quite reasonable.克劳斯医生认为这些政策是很合理的。But if what her participants told her is true, not all dentists are heeding their own professional bodys advice.如果研究参与者所告知的都是事实的话,可见并不是所有牙科医生都留心自身的建议。Most of those who took part in the study reported having at least one X-ray a year.大多数参与研究的人表示一年至少拍了一次x 光。Dr Clauss work, then, is a timely reminder that X-rays are dangerous, that dentists should use them sparingly and that patients who have suspicions about their use are not necessarily paranoid.克劳斯医生的工作及时地提醒了我们,拍x光是有危险的,牙医应该保守地使用它们,这样看来病人们对x光的疑虑并不是所谓的妄想。 /201403/278869上海市长海医院隆胸多少钱上海复旦大学附属眼耳鼻喉科医院吸脂手术价格



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