科技英語(yǔ)五單元

科技英語(yǔ)五單元科技英語(yǔ)五單元科技英語(yǔ)五單元xxx公司科技英語(yǔ)五單元文件編號(hào)：文件日期：修訂次數(shù)：第1.0次更改批準(zhǔn)審核制定方案設(shè)計(jì)，管理制度五單元Effortstocombatagingandextendhumanlifedateatleastasfarbackas3500.,andself-proclaimedexpertshavetoutedanti-agingelixirseversince.Indeed,theprospectofimmortalityhasalwayshaduniversalappeal,spurringAlexandertheGreatandPoncedeLeóntosearchforthelegendaryFountainofYouthandfeedingalchemists'desiretomanufacturegold(oncebelievedtobethemostpotentanti-agingsubstanceinexistence).Butthehawkingofanti-aging“therapies”hastakenaparticularlytroublingturnoflate.Disturbinglylargenumbersofentrepreneursareluringgullibleandfrequentlydesperatecustomersofallagesto“l(fā)ongevity”clinics,claimingascientificbasisfortheanti-agingproductstheyrecommendand,often,sell.Atthesametime,theInternethasenabledthosewhoseeklucrefromsupposedanti-agingproductstonewcustomerswithease.努力與衰老作斗爭(zhēng)并延長(zhǎng)人類(lèi)的壽命至少可以追溯到公元前3500年前，從那時(shí)起那些自詡的專(zhuān)家就一直兜售抗衰老長(zhǎng)生不老藥，的確，長(zhǎng)生不老一直對(duì)人們具有普遍的吸引力，促使亞歷山大大帝和龐塞·德·里昂尋找傳說(shuō)中的“青春之泉”，并滿(mǎn)足煉金術(shù)士們制造黃金的欲望（人們一度認(rèn)為它是目前最有效的抗衰老物質(zhì)）。但是抗衰老的兜售方式的轉(zhuǎn)變令人擔(dān)憂(yōu)。令人不安的是，大量的企業(yè)家都在引誘各個(gè)年齡層的易受騙和常常是絕望的顧客去“長(zhǎng)壽”診所，聲稱(chēng)他們所推薦的抗衰老產(chǎn)品有科學(xué)的依據(jù)，并常常把產(chǎn)品賣(mài)給他們。與此同時(shí)，互聯(lián)網(wǎng)使那些從所謂的抗衰老產(chǎn)品中尋找利潤(rùn)的人可以輕松地接觸到新客戶(hù)。Alarmedbythesetrends,scientistswhostudyaginghaveissuedapositionstatementcontainingthiswarning:nocurrentlymarketedintervention－none－h(huán)asyetbeenprovedtoslow,stoporreversehumanaging,andsomecanbedownrightdangerous.研究老化問(wèn)題的科學(xué)家對(duì)這些趨勢(shì)感到震驚，他們發(fā)表了一份立場(chǎng)聲明，其中包含了這樣的警告：目前還沒(méi)有市場(chǎng)上的干預(yù)措施能夠減緩、阻止或逆轉(zhuǎn)人類(lèi)的衰老，其中一些措施可能是非常危險(xiǎn)的。Anydiscussionofagingshouldfirstclarifyitsterms.Variousdefinitionshavebeenproposed,butwethinkofagingastheaccumulationofrandomdamagetothebuildingblocksoflife－especiallytoDNA,certainproteins,carbohydratesandlipids(fats)－thatbeginslifeearlyinlifeandeventuallyexceedsthebody'sself-repaircapabilities.Thisdamagegraduallyimpairsthefunctioningofcells,tissues,organsandorgansystems,therebyvulnerabilitytodiseaseandgivingrisetothecharacteristicmanifestationsofaging,suchasalossofmuscleandbonemass,adeclineinreactiontime,compromisedhearingandvision,andreducedelasticityofskin.任何關(guān)于衰老的討論都應(yīng)該首先澄清它的術(shù)語(yǔ)。人們提出了各種不同的定義，但我們認(rèn)為衰老是對(duì)生命構(gòu)成要素的隨機(jī)損傷的積累——特別是對(duì)DNA、某些蛋白質(zhì)、碳水化合物和脂類(lèi)（脂肪）--這種損傷開(kāi)始于生命早期，最終超過(guò)了身體的自我修復(fù)能力。這種損害逐漸損害細(xì)胞、組織、器官和器官系統(tǒng)的功能，從而易患病，并導(dǎo)致衰老的典型表現(xiàn)，如肌肉萎縮和骨量疏松，反應(yīng)時(shí)間下降，聽(tīng)力和視力受損，皮膚彈性降低。Aging,inourview,makesusevermoresusceptibletosuchillsasheartdisease,Alzheimer'sdisease,strokeandcancer,buttheseage-relatedconditionsaresuperimposedonaging,notequivalenttoit.Therefore,evenifsciencecouldeliminatetoday'sleadingkillersofolderindividuals,agingwouldcontinuetooccur,ensuringthatdifferentmaladieswouldtaketheirplace.Inaddition,itwouldguaranteethatonecrucialbodycomponentoranother－say,thecardiovascularsystem－wouldeventuallyexperienceacatastrophicfailure.Itisaninescapablebiologicalrealitythatoncetheengineoflifeswitcheson,thebodyinevitablysowstheseedsofitsowndestruction.在我們看來(lái)，衰老使我們更易得心臟病、阿爾茨海默病、中風(fēng)和癌癥等疾病，但這些與年齡相關(guān)的疾病是衰老帶來(lái)的附加物，并不等同于衰老。因此，即使科學(xué)能夠消滅當(dāng)今導(dǎo)致老年人死亡的主要?dú)⑹?，衰老也?huì)繼續(xù)發(fā)生，會(huì)讓不同的疾病取代他們。此外，衰老也會(huì)讓人體的某個(gè)或幾個(gè)重要的組成部分-比如心血管系統(tǒng)，最終會(huì)經(jīng)歷一場(chǎng)災(zāi)難性的失敗。這是一個(gè)不可避免的生物現(xiàn)實(shí)，一旦生命的引擎啟動(dòng)，身體就不可避免地播下自我毀滅的種子。Menandwomeninthedevelopedworldtypicallylivelongernow(75and80years,respectively)thantheydidthroughoutmuchofhistory(about25years)becausehumaningenuity－whichbroughtussanitationsystems,vaccines,antibioticsandsoon－h(huán)ashadphenomenalsuccessinthwartingtheinfectiousandparasiticdiseasesresponsibleforagreatdealofprematuredeath.Welivelongernownotbecausewehavealteredthewayweagebutbecausewehavealteredthewaywelive.發(fā)達(dá)國(guó)家的男性和女性通常比他們?cè)谡麄€(gè)歷史（大約25年）中活得更久（分別為75歲和80歲），因?yàn)槿祟?lèi)的智慧，衛(wèi)生系統(tǒng)、疫苗、抗生素等為我們帶來(lái)了非凡的成功，阻止了傳染病和寄生蟲(chóng)引起的疾病帶來(lái)的大量的早逝。我們現(xiàn)在的壽命更長(zhǎng)，不是因?yàn)楦淖兞怂ダ系姆绞?，而是因?yàn)槲覀兏淖兞宋覀兊纳罘绞健houghinevitable,agingisnot,assomemightthink,ageneticallyprogrammedprocess,playingitselfoutonarigidlypredeterminedtimeschedule.Thewayevolutionworksmakesitimpossibleforustopossessgenesthatarespecificallydesignedtocausephysiologicaldeclinewithageortocontrolhowlongwelive.Justasanautomobiledoesnothaveabuilt-inplanfordeclinewritteninitsblueprints,wedonotpossessgeneticintructionsthattellourbodieshowtoageorwhentodie.雖然衰老是不可避免的，但衰老并不是一些人所認(rèn)為的那樣，一個(gè)基因編程的過(guò)程，而是按照預(yù)定的時(shí)間表執(zhí)行的。進(jìn)化的方式使得我們不可能擁有特定設(shè)計(jì)的基因，這些基因會(huì)隨著年齡的增長(zhǎng)而引起生理上的衰退，或者控制我們的壽命。就像汽車(chē)藍(lán)圖中沒(méi)有內(nèi)置的衰退計(jì)劃一樣，我們也沒(méi)有基因指令告訴我們的身體如何衰老或何時(shí)死亡。Withoutadoubt,ahostofourgenesinfluenceaging,buttheydosoindirectly,asaninadvertentby-productofprocessesinvolvedingrowth,development,andthemaintenanceofhealthandvigor.Thelackofaspecificgeneticprogramforaginganddeathmeansthattherearenoquickfixesthatwillpermitustotreatagingasifitwereadisease.Asinglegeneticinterventioninanorganismascomplexasahumanbeingwouldhavelittlechanceofcombatingtheprobablyvastarrayofgenesandbiologicalactivitiesthatplaysubtle,unpredictablepartinthetimingofourultimatedemise.毫無(wú)疑問(wèn)，我們的很多基因都會(huì)影響衰老，但它們是間接的，是生長(zhǎng)、發(fā)育、保持健康和活力過(guò)程中的副產(chǎn)品。缺乏針對(duì)衰老和死亡的特定基因計(jì)劃意味著，我們沒(méi)有快速的解決辦法，可以把衰老當(dāng)作一種疾病來(lái)對(duì)待。對(duì)一個(gè)像人類(lèi)這樣復(fù)雜的有機(jī)體進(jìn)行單一的基因干預(yù)，就幾乎沒(méi)有機(jī)會(huì)與在我們最終滅亡的時(shí)間安排中扮演微妙、不可預(yù)測(cè)角色的大量基因和生物活動(dòng)作斗爭(zhēng)。Onwhatgroundsdoweassertsovehementlythatnopurpotedanti-aginginterventionhasbeenprovedtomodifyagingToassesswhetheraninterventionhasaffectedabiologicalprocess,researchersneedayardstickformeasuringthatthiscase,nosingleoraggregateage-relatedphenomenonhasprovedtobeareliableindicatoroftherateofaginginhumansorotherspecies.Withoutayardstick,therecanbenoassurancethataninterventionwassuccessful.基于什么樣的理由，我們?nèi)绱藦?qiáng)烈地?cái)嘌?，沒(méi)有任何有針對(duì)性的抗衰老干預(yù)已被證明是修改老化為了評(píng)估干預(yù)是否影響了生物過(guò)程，研究人員需要一個(gè)衡量該過(guò)程的標(biāo)準(zhǔn)。在這種情況下，事實(shí)證明，沒(méi)有任何單一或總體與年齡有關(guān)的現(xiàn)象是人類(lèi)或其他物種老化速度的可靠指標(biāo)。沒(méi)有標(biāo)準(zhǔn)，就不能測(cè)量，沒(méi)有測(cè)量，就不能保證干預(yù)是成功的。Somepeoplemightwonderwhetherfollowingtoday'spublichealthrecommendationsfordietandexercisecanserveasamorenaturalFountainofYouth.Goodnutritionandregularexercisedoreducetheriskofvariousdiseasesand,inthatway,mayextendthedurationoflifeformanypeople－therebyservingasthebestcurrentprescriptionforalongandhealthylife.Asistrueofotherinterventions,though,noonehasshownthatdietorexercise,orboth,directlyinfluencesaging.一些人可能想知道，按照今天的公共衛(wèi)生建議，節(jié)食和鍛煉是否可以成為一個(gè)更自然的青春源泉。良好的營(yíng)養(yǎng)和有規(guī)律的鍛煉確實(shí)可以降低患各種疾病的風(fēng)險(xiǎn)，這樣，許多人的壽命可能會(huì)延長(zhǎng)，從而成為目前長(zhǎng)壽和健康生活的最佳處方。然而，正如其他干預(yù)措施也是一樣，沒(méi)有人表明飲食或鍛煉，或兩者都直接影響著衰老。Anotheravenueofresearchmayalsoleadtotrueaginginterventions.Investigatorshaveknownfordecadesthatcaloricrestrictionextendslifeandthedurationofgoodhealthinallspeciesithasbeenstudied,aslongasthedietincludesenoughnutritionforroutinemaintenanceofthebody.Thesefindingssuggestthatcaloricrestricitonmighthavesimilareffectsinhumans.Giventhatfewpeoplewouldeverreducetheirfoodintakeenoughtolengthentheirlives,biologistsarenowtryingtodiscoverthemechanismthatunderliesthebenefitsofcaloricrestrictionandtofindagentsthatmightmimicthosehelpfuleffectsinpeoplewithoutforcingthemtogohungry.另一個(gè)研究途徑也可能導(dǎo)致真正的老齡化干預(yù)。幾十年來(lái)，研究人員已經(jīng)知道，只要飲食中含有足夠的營(yíng)養(yǎng)以維持身體的正常運(yùn)轉(zhuǎn)，熱量限制就能延長(zhǎng)所有被研究物種的壽命和健康時(shí)間。這些發(fā)現(xiàn)表明，熱量限制子可能對(duì)人類(lèi)有類(lèi)似的影響。考慮到很少有人會(huì)減少食物攝入量，從而延長(zhǎng)壽命，生物學(xué)家現(xiàn)在正在試圖發(fā)現(xiàn)熱量限制的好處背后的機(jī)制，并尋找可以模仿這些有益效果的物質(zhì)，而不會(huì)迫使他們挨餓。Anumberofscientistslookatcurrentresearchtrendsandfeelhelpful.Theycanenvisionatimewhentreatmentsbasedonanunderstandingofagingcanhelpslowitsprogressionandwhennotyetspecialized(stem)cellscanbecoaxedtorepairandrejuvenatedamagedtissues,enablingpeopletoremainvigorouslongerthantheywouldwithoutmedicalassistance.Notallresearcherssharethatoptimism,though.Someassertthataging'scomplexitywillforevermilitateagainstthedevelopmentofanti-agingtherapies.許多科學(xué)家看到當(dāng)前的研究趨勢(shì)并感到有幫助。他們可以設(shè)想這樣一個(gè)時(shí)代：基于對(duì)衰老的理解的治療能夠幫助延緩衰老的進(jìn)程，那時(shí)人們可以誘導(dǎo)尚未分化的干細(xì)胞修復(fù)和恢復(fù)受損的組織，使人們比沒(méi)有醫(yī)療援助時(shí)可以更長(zhǎng)時(shí)間的保持旺盛的活力，不過(guò)，并非所有研究者都持這種樂(lè)觀(guān)態(tài)度。一些人斷言，老化的復(fù)雜性將永遠(yuǎn)不利于抗衰老療法的發(fā)展。Onethingisindisputable:thenum