科技英语五单元

-五单元Efforts to combat aging and extend human life date at least as far back as 3500 B.C.,and self-proclaimed experts have touted anti-aging elixirs ever since. Indeed, the prospect of immortality has always had universal appeal, spurring Alexander the Great and Ponce de Len to search for the legendary Fountain of Youth and feeding alchemists desire to manufacture gold (once believed to be the most potent anti-aging substance in existence). But the hawking of anti-aging “therapies” has taken a particularly troubling turn of late. Disturbingly large numbers of entrepreneurs are luring gullible and frequently desperate customers of all ages to “longevity” clinics, claiming a scientific basis for the anti-aging products they recommend and, often, sell. At the same time, the Internet has enabled those who seek lucre from supposed anti-aging products to new customers with ease. 努力与衰老作斗争并延长人类的寿命至少可以追溯到公元前3500年前，从那时起那些自诩的专家就一直兜售抗衰老长生不老药，的确，长生不老一直对人们具有普遍的吸引力，促使亚历山大大帝和庞塞德里昂寻找传说中的“青春之泉”，并满足炼金术士们制造黄金的欲望（人们一度认为它是目前最有效的抗衰老物质）。但是抗衰老的兜售方式的转变令人担忧。令人不安的是，大量的企业家都在引诱各个年龄层的易受骗和常常是绝望的顾客去“长寿”诊所，声称他们所推荐的抗衰老产品有科学的依据，并常常把产品卖给他们。与此同时，互联网使那些从所谓的抗衰老产品中寻找利润的人可以轻松地接触到新客户。Alarmed by these trends, scientists who study aging have issued a position statement containing this warning: no currently marketed intervention nonehas yet been proved to slow, stop or reverse human aging, and some can be downright dangerous. 研究老化问题的科学家对这些趋势感到震惊，他们发表了一份立场声明，其中包含了这样的警告：目前还没有市场上的干预措施能够减缓、阻止或逆转人类的衰老，其中一些措施可能是非常危险的。Any discussion of aging should first clarify its terms. Various definitions have been proposed, but we think of aging as the accumulation of random damage to the building blocks of lifeespecially to DNA, certain proteins, carbohydrates and lipids (fats)that begins life early in life and eventually exceeds the bodys self-repair capabilities. This damage gradually impairs the functioning of cells, tissues, organs and organ systems, thereby vulnerability to disease and giving rise to the characteristic manifestations of aging, such as a loss of muscle and bone mass, a decline in reaction time, compromised hearing and vision, and reduced elasticity of skin. 任何关于衰老的讨论都应该首先澄清它的术语。人们提出了各种不同的定义，但我们认为衰老是对生命构成要素的随机损伤的积累特别是对DNA、某些蛋白质、碳水化合物和脂类（脂肪）-这种损伤开始于生命早期，最终超过了身体的自我修复能力。这种损害逐渐损害细胞、组织、器官和器官系统的功能，从而易患病，并导致衰老的典型表现，如肌肉萎缩和骨量疏松，反应时间下降，听力和视力受损，皮肤弹性降低。Aging, in our view, makes us ever more susceptible to such ills as heart disease, Alzheimers disease, stroke and cancer, but these age-related conditions are superimposed on aging, not equivalent to it. Therefore, even if science could eliminate todays leading killers of older individuals, aging would continue to occur, ensuring that different maladies would take their place. In addition, it would guarantee that one crucial body component or anothersay, the cardiovascular systemwould eventually experience a catastrophic failure. It is an inescapable biological reality that once the engine of life switches on, the body inevitably sows the seeds of its own destruction.在我们看来，衰老使我们更易得心脏病、阿尔茨海默病、中风和癌症等疾病，但这些与年龄相关的疾病是衰老带来的附加物，并不等同于衰老。因此，即使科学能够消灭当今导致老年人死亡的主要杀手，衰老也会继续发生，会让不同的疾病取代他们。此外，衰老也会让人体的某个或几个重要的组成部分-比如心血管系统，最终会经历一场灾难性的失败。这是一个不可避免的生物现实，一旦生命的引擎启动，身体就不可避免地播下自我毁灭的种子。Men and women in the developed world typically live longer now (75 and 80 years, respectively) than they did throughout much of history (about 25 years) because human ingenuitywhich brought us sanitation systems, vaccines, antibiotics and so onhas had phenomenal success in thwarting the infectious and parasitic diseases responsible for a great deal of premature death. We live longer now not because we have altered the way we age but because we have altered the way we live. 发达国家的男性和女性通常比他们在整个历史（大约25年）中活得更久（分别为75岁和80岁），因为人类的智慧，卫生系统、疫苗、抗生素等为我们带来了非凡的成功，阻止了传染病和寄生虫引起的疾病带来的大量的早逝。我们现在的寿命更长，不是因为改变了衰老的方式，而是因为我们改变了我们的生活方式。 Though inevitable, aging is not, as some might think, a genetically programmed process, playing itself out on a rigidly predetermined time schedule. The way evolution works makes it impossible for us to possess genes that are specifically designed to cause physiological decline with age or to control how long we live. Just as an automobile does not have a built-in plan for decline written in its blueprints, we do not possess genetic intructions that tell our bodies how to age or when to die. 虽然衰老是不可避免的，但衰老并不是一些人所认为的那样，一个基因编程的过程，而是按照预定的时间表执行的。进化的方式使得我们不可能拥有特定设计的基因，这些基因会随着年龄的增长而引起生理上的衰退，或者控制我们的寿命。就像汽车蓝图中没有内置的衰退计划一样，我们也没有基因指令告诉我们的身体如何衰老或何时死亡。Without a doubt, a host of our genes influence aging, but they do so indirectly, as an inadvertent by-product of processes involved in growth, development, and the maintenance of health and vigor. The lack of a specific genetic program for aging and death means that there are no quick fixes that will permit us to treat aging as if it were a disease. A single genetic intervention in an organism as complex as a human being would have little chance of combating the probably vast array of genes and biological activities that play subtle, unpredictable part in the timing of our ultimate demise. 毫无疑问，我们的很多基因都会影响衰老，但它们是间接的，是生长、发育、保持健康和活力过程中的副产品。缺乏针对衰老和死亡的特定基因计划意味着，我们没有快速的解决办法，可以把衰老当作一种疾病来对待。对一个像人类这样复杂的有机体进行单一的基因干预，就几乎没有机会与在我们最终灭亡的时间安排中扮演微妙、不可预测角色的大量基因和生物活动作斗争。On what grounds do we assert so vehemently that no purpoted anti-aging intervention has been proved to modify aging? To assess whether an intervention has affected a biological process, researchers need a yardstick for measuring that process.In this case, no single or aggregate age-related phenomenon has proved to be a reliable indicator of the rate of aging in humans or other species. Without a yardstick, there can be no assurance that an intervention was successful. 基于什么样的理由，我们如此强烈地断言，没有任何有针对性的抗衰老干预已被证明是修改老化？为了评估干预是否影响了生物过程，研究人员需要一个衡量该过程的标准。在这种情况下，事实证明，没有任何单一或总体与年龄有关的现象是人类或其他物种老化速度的可靠指标。没有标准，就不能测量，没有测量，就不能保证干预是成功的。Some people might wonder whether following todays public health recommendations for diet and exercise can serve as a more natural Fountain of Youth. Good nutrition and regular exercise do reduce the risk of various diseases and, in that way, may extend the duration of life for many peoplethereby serving as the best current prescription for a long and healthy life. As is true of other interventions, though, no one has shown that diet or exercise, or both, directly influences aging. 一些人可能想知道，按照今天的公共卫生建议，节食和锻炼是否可以成为一个更自然的青春源泉。良好的营养和有规律的锻炼确实可以降低患各种疾病的风险，这样，许多人的寿命可能会延长，从而成为目前长寿和健康生活的最佳处方。然而，正如其他干预措施也是一样，没有人表明饮食或锻炼，或两者都直接影响着衰老。Another avenue of research may also lead to true aging interventions. Investigators have known for decades that caloric restriction extends life and the duration of good health in all species it has been studied, as long as the diet includes enough nutrition for routine maintenance of the body. These findings suggest that caloric restriciton might have similar effects in humans. Given that few people would ever reduce their food intake enough to lengthen their lives, biologists are now trying to discover the mechanism that underlies the benefits of caloric restriction and to find agents that might mimic those helpful effects in people without forcing them to go hungry. 另一个研究途径也可能导致真正的老龄化干预。几十年来，研究人员已经知道，只要饮食中含有足够的营养以维持身体的正常运转，热量限制就能延长所有被研究物种的寿命和健康时间。这些发现表明，热量限制子可能对人类有类似的影响。考虑到很少有人会减少食物摄入量，从而延长寿命，生物学家现在正在试图发现热量限制的好处背后的机制，并寻找可以模仿这些有益效果的物质，而不会迫使他们挨饿。A number of scientists look at current research trends and feel helpful. They can envision a time when treatments based on an understanding of aging can help slow its progression and when not yet specialized (stem) cells can be coaxed to repair and rejuvenate damaged tissues, enabling people to remain vigorous longer than they would without medical assistance. Not all researchers share that optimism, though. Some assert that agings complexity will forever militate against the development of anti-aging therapies. 许多科学家看到当前的研究趋势并感到有帮助。他们可以设想这样一个时代：基于对衰老的理解的治疗能够帮助延缓衰老的进程，那时人们可以诱导尚未分化的干细胞修复和恢复受损的组织，使人们比没有医疗援助时可以更长时间的保持旺盛的活力，不过，并非所有研究者都持这种乐观态度。一些人断言，老化的复杂性将永远不利于抗衰老疗法的发展。One thing is indisputable: the number of elderly peo