课后翻译pptConvertorWord格式文档下载.docx

课后翻译pptConvertorWord格式文档下载.docx

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1.5Vitaminsareclassified/distinguishedbythelettersofthealphabet,suchasvitaminA,C,D,E,KandB-complex.

1.6Vitaminsandmineralsarefoundinsmallamountsandareneededinminutequantities,ascomparedwiththeothernutrients.

1.7Thediseaseswhichdevelopfromtheabsenceofvitaminsareknownasvitamindeficiencydiseases.Forexample,alackofvitaminAbringsaboutnightblindness;

adeficiencyofvitaminDresultinrickets.

1.8Somevitaminsaresolubleinfatswhereasothersaresolubleinwater.Theyare,therefore,termedfat-solubleandwatersolublevitaminsrespectively.

1.9Inadditiontothegeneralnutrients,anothertwogroupsofnutrients,vitaminsandinorganic,ormineral,saltsarealsorequiredbythebody.

1.10Mostnutrientscontainmorethanonenutrient,butnosinglefoodcontainsallthenutrientsintheamountsyouneed.

1.2Fruitsandvegetablesarechock-fullofavarietyofantioxidantswhichcansnuffoutoxygenfreeradicals,substancethatarethoughttomakecellsmoresusceptibletocancer.

UnitOne-B

1.6SomestudiesofanimalsandhumanshavesuggestedthatvitaminAofferssomeprotectionagainstlungcancer.

1.8Animalstudiesshowthatgarlicblockscarcinogensthathavebeenlinkedtocolonandstomachcancer.

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1.9Adietofmorefruitsandvegetableswillundoubtedlyplayamajorroleinreducingcancerincidenceaswellasthenumberofdeathscausedbythedisease.

1.1Overwhelmingstatisticalevidenceshowsthatsmokersaremorelikelytodevelopcancerofthelung,throat,andtonguethanarenon-smokers.

1.3Awell-balanceddietwillgiveyourbodyvariousnutrientsofvitamins,minerals,proteins,starches,andsugarsthatitneedstooperatesmoothly.

1.4Theriskoflungcancerisdirectlyrelatedtothenumberofcigarettessmokedeachday–thehigherthenumber,thehighertherisk.

1.5Evensmokersmaybeprotectedfromdevelopinglungcancerbyadailyportionofcarrots,spinachoranyothervegetablesandfruits.

1.7Furtherstudieswillbenecessarybeforethelinkbetweenlungcancerandcarotenecanbefirmlyestablished.

1.10Beta-carotenenotonlyhasadirecttoxiceffectontumorcells,butalsoreducesthegrowthoflung-cancercellsandalteredtheproteinsneededfortumorstogrow.

2.1Brieflyspeaking,ascientistdiffersfromanartistmainlyinthatascientistnotonlyinterpretstheouterworld,butalsotriestotransformitintoabetterone.

UnitTwo-A

2.2Sciencebeginswithnecessity,curiosity,andquestionsabouttheunexplainedphenomenoninnature.

2.3Thewaysinwhichanelementoracompoundcombinesorreactswithotherthingsareitschemicalproperties.

2.4Thechemistisinterestedinthecompositionandpropertiesofsubstancesandthetransformationtheyundergoduringachemicalreaction.

2.5Itisveryeasytofallintothehabitoftakingsomepainkillerwhenthereisanyslightpain.

2.6Thedelicateoperationsperformedbysurgeonstodaywouldnotbepossiblewithoutanesthetics.

2.7Todayitisgenerallyrecognizedthathumanbodyisachemicalfactoryinwhichcountlesscomplexchemicalandphysicalchangesareconstantlytakingplace.

2.8Thesubstancesaltiscomposedofthemetalsodiumandthecorrosivegaschlorine,butitschemicalpropertiesarequitedifferentfromthoseofsodiumandchlorine.

2.9Chemotherapyisthetreatmentofdiseasebytheadministrationofchemicalsubstancewhichkillsorpreventsthegrowthofpathogenicorganismswithinthebody.

2.10Substancesthatlessenpainbutdonotaffectothersensationsarecalledpainrelievingdrugs.

2.1Instructorsincollegeintroductorycoursesarefacedwithanextremelyformidabletask,forthereisagreatdiversityofpreparationinchemistrywithwhichstudentsentercollege.

UnitTwo-B

2.2Ascientificfactisanobservationaboutnaturethatcanusuallybereproducedatwill.

2.3Ifyouhaveanydoubtaboutascientificfactyoucaneasilysetupanexperimentthatwillreadilydemonstratethefactanew.

2.4Itisnoteasytoconstructachemistrycoursewhichisbothhighlystructuredforthepoorly-preparedandhighlyflexibleforthewell-preparedstudents.

2.5ThesystematicdevelopmentofthephysicalintuitionofstudentsisviewedastheessenceofaModelsApproachofChemistry.

2.6Ofthethreefactorsinvolvedinmasteringascienceunderstandingtheconceptinphysicaltermsisthekeylinkwhichtiestogetherfactsandconcepts.

2.7Forascientifictheorytohavemuchvalue,itmustnotonlyexplainthepertinentfactsandlawsathand,butitmustalsobeabletoexplainnewfactsandlawsthatareobviouslyrelated.

2.8Todevelopsystematicallythephysicalintuitionofstudentsinstructorsinbasicchemistrycoursemayconcentrateontheconstructionandapplicationofmodels.

2.9Theexperimentresultsshouldagreewiththepredictionsofmodels.Forthatreason,theprocessofmodelbuildinginvolvesanever-endinginterplaybetweenexperimentandtheory.

2.10TheModelsApproachofChemistryisnotonlythebestwaytotietogetherchemicalfactsandconcepts,butinvolvesthedirectparticipationofstudentsineverystepofthemodelbuilding.

3.1Itisnotmanyyearssinceamanwhohadtohaveanoperationfeltitspain.

UnitThree-A

3.2Itisattributabletothediscoveryofanestheticsthatsurgeonscannowperformallkindsofoperationswithoutcausingpain.

3.3Spinalanesthesiaproducesexcellentanesthesiaandrelaxationfortheperformanceofmanyoperationsonthelowerpartsofthebody.

3.4Theexactmechanisminwhichthegeneralanestheticdrugsexerttheireffectonthebrainisstillunknown,althoughmanytheorieshavebeenproposed.

3.5Theintroductionofanestheticstosurgeryhasmadepossiblemuchmoredelicateandlengthyoperations,thusgreatlyextendingthefieldofsurgery.

3.6Anestheticsarethedrugswhicharesedativeintheiractionuponbodybutwhichalsoproduceinsensibilitytopain.

3.7Contrarytowhatonemightthink,it’sonly50yearsorsosincepenicillin,theantibioticonceregardedasthewonderdrug,cameintobeing.

3.8Scientistspointoutthatsincethesedativeactionofadrugresultsfromitseffectonthenerves,itmustpossesssolubilityinthefluidsofthebodywhichsurroundthenerves.

3.9Ananestheticmustbevolatileifitistobeadministeredthroughoralinhalation,whilethosewhichcanbeadministeredthroughtherectumorinjectedintothespinedonothavetobevolatile.

3.10Inspiteofthedangerofapatient’scontractingpneumoniaaftertheuseofetherasananesthetic,etherisstillwidelyemployedbecausetheanesthesiaitproducesisoneofdeeprelaxation.

Peopleareinclinedtothinkthattheantibioticsareoneofhumandiscoveries.Theyareactuallynaturalproducts.SincetheBritishbiologistAlexanderFlemingin1928discoveredasubstancereleasedbythePenicilliumfungustocombatmicrobes,peoplehavecometounderstandthattheycanproduceefficientantibiotics.

UnitFour-A

Asamatteroffact,antibioticsareproducedbythoseorganism,namelygermsandfungi,intheprocessofdestroying.AfterAlexanderFlemingdiscoveredpenicillin,SelmanWaksmanisolatedstreptomycinfromthesoilbacteriumStreptomycesgriseus.Thisproblemisbecomingasubjectofdiscussion.

Antibioticsareveryusefulinmedicalscience,becausenotonlytheykilluselessmicrobesbutalsotheydon’tdestroyanyhumannormalcells,whicharegreatlydifferentfrombacteriacells.Thesetwoknidsofcellscanbeavoidedtobedestroyedatthesametime.

Hence,antibiotics,called,“magicbullets”,maybeusedtotargetsomemicrobes.Thispropertymakesanessentialdifferencebetweenantibioticsandantimicrobials,thelatteristoxictomanycells,bothgermcellsandhumannormalcells.

4.1Althoughmostimmunotoxicologicaltestswereoriginallydevelopedprimarilyfortheevaluationofenvironmentalchemicalsandfoodadditives,thesemethodsareeasilyadaptedforuseinpharmaceuticalevaluation.

UnitFour-B

4.2OngoingresearchinbothEuropeandtheUnitedStateshasfocusedonimmunotoxicitytestinginrodentswithparticularemphasisondetectingimmunosuppression.

4.3Directimmunotoxicitymayoccurwhentheimmunesystemisthetargetofchemicalinsults,resultinginalteredimmunefunction;

thisinturncanresultindecreasedresistancetoinfection,certainformsofneoplasia,orimmunedysregulationorstimulationthatcanexacerbateorfacilitatedevelopmentofallergyorautoimmunity.

4.4I