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简介：DNAcondensationisanimportantprocessinmanyfieldsincludinglifesciences,polymerphysics,andappliedtechnology.Inthenucleus,DNAiscondensedintochromosomes.Inpolymerphysics,DNAistreatedasasemi-flexiblemoleculeandapolyelectrolyte.Manyagents,includingmulti-valentcations,surfactants,andneutralpoorsolvents,cancauseDNAcondensation,alsoreferredtoascoil–globuletransition.Moreover,DNAcondensationhasbeenusedforextractionandgenedeliveryinappliedtechnology.ManyphysicaltheorieshavebeenpresentedtoelucidatethemechanismunderlyingDNAcondensation,includingthecounterioncorrelationtheory,theelectrostaticzippertheory,andthehydrationforcetheory.Recentlyseveralsingle-moleculestudieshavefocusedonDNAcondensation,sheddingnewlightonoldconcepts.Inthisdocument,themulti-fieldconceptsandtheoriesrelatedtoDNAcondensationareintroducedandclarifiedaswellastheadvancesandconsiderationsofsingle-moleculeDNAcondensationexperimentsareintroduced.

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简介：AdoublehelixmodelofchargetransportinDNAmoleculeisgivenandthetransmissionspectraoffourDNAsequencesareobtained.ThecalculatedresultsshowthatthetransmissioncharacteristicsofDNAarenotonlyrelatedtothelongitudinaltransportbutalsotothetransversetransportofmolecule.Theperiodicsequencewiththesamecompositionhasstrongerconductionability.Withtheincreasingofbasescomposition,theconductiveabilityreduces,buttheweightofθdirectionrisesinchargetransfer.

简介：电学实验中，电路元件间的连接一般采用导线之间的直接绞接、导线与接线柱间的螺母压接，导线与接线柱间的直接夹接、焊接等几种方式。

简介：由直接diagonalizing脱氧核糖核酸酸(DNA)的梯子模型的Hamiltonian分子，状态的密度被获得。DNA作为一个售票员表现，这被发现什么时候内部链跳跃比小两次intrachain不那样，DNA作为一个半导体表现。

简介：Chaosgamerepresentation(CGR)isaniterativemappingtechniquethatprocessessequencesofunits,suchasnucleotidesinaDNAsequenceoraminoacidsinaprotein,inordertodeterminethecoordinatesoftheirpositionsinacontinuousspace.Thisdistributionofpositionshastwofeatures:oneisunique,andtheotherissourcesequencethatcanberecoveredfromthecoordinatessothatthedistancebetweenpositionsmayserveasameasureofsimilaritybetweenthecorrespondingsequences.ACGR-walkmodelisproposedbasedonCGRcoordinatesfortheDNAsequences.TheCGRcoordinatesareconvertedintoatimeseries,andalong-memoryARFIMA(p,d,q)model,whereARFIMAstandsforautoregressivefractionallyintegratedmovingaverage,isintroducedintotheDNAsequenceanalysis.ThismodelisappliedtosimulatingrealCGR-walksequencedataoftengenomicsequences.Remarkablylong-rangecorrelationsareuncoveredinthedata,andtheresultsfromthesemodelsarereasonablyfittedwiththosefromtheARFIMA(p,d,q)model.

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简介：介绍了一种利用游标卡尺和游标角度尺所组合成的新型器具进行非接触法距离的测量，从理论上和实际操作上对仪器可能达到的精度和产生的误差，以及如何减少误差提高精度进行了分析和描述。

简介：TheDNA-dependentproteinkinasecatalyticsubunit(DNA-PKcs)playsamajorroleinDNAdamagesignalingandrepair,andisalsofrequentlyover-expressedintumormetastasis.WeusedisogeniccelllinesexpressingdifferentlevelsofDNA-PKcstoinvestigatetheroleofDNA-PKcsinmetastaticdevelopment.Interestingly,ourresultsshowedthatX-rayirradiationinducedthemetastasisofDNA-PKcspositive(M059K)butnotnegative(M059J)cells;however,genisteincouldsuppresstheradiation-inducedmetastaticpotentialofM059Kcells(Fig.1).Theconcretemechanismsunderlyingthisphenomenonwillbeinvestigatednextyear.

简介：Heavyionirradiationattractalargeinterestfortwoapplications:radiotherapyandspaceradiationprotectioninmannedspacemissions.ExposuretoheavyionsradiationresultsinmultipleeffectsthroughDNAdamageinduction.Single-cellgelelectrophoresisorcometassayisknownforitsabilitytodetectDNAdamageatthesinglecelllevelandhasbeenusedforyearstoassessDNAdamage.ItcandetectlowlevelsofDNAstrandbreaksinashorttime,justusingafewsamplecells.DNAdoublestrandbreaks(DSBs)aremeasuredattheneutralcometassaycondition;underthealkalinecometassayconditionbothDNAsinglestrandbreaks(SSBs)andpartDSBsaredetected.Thetwodimensionalcometassayisamodificationofthetwooriginalcometassay,cansimultaneouslydetectDNASSBsandDSBsinthesamehumanspermatozoa.

简介：预紧接触式结构是指结构中存在预紧构件，预紧构件与其他构件之间是相互接触的。在工程中经常遇到预紧接触式结构，如产品在包装时采用的泡沫垫层、武器设计中使用的垫层等，这些结构的共同点是在正常工作环境中垫层总处于受压状态，即垫层结构在有效的工作环境中沿厚度方向是不能承受拉力的。预紧接触式系统中，在预紧力一定的条件下，结构的动力学特性会随激励力幅值大小以及频率的变化而变化。在小幅值振动的条件下，可以认为系统是线性的，在幅值较大时，结构会表现出明显的非线陛特征。当激励满足一定条件时，系统会产生滑移、接触分离，而这往往是工程实际中所不允许的。分析此类问题需要了解结构的动态特性，而滑移、接触分离将导致系统的强非线性，就不能采用拟线性的方法来处理这类问题。

简介：AlterationsinDNArepair,cellcycle,andapoptoticpathwaysareoftenassociatedwithcancerriskandradiationsensitivity.IndividualswithreducedDNAdamageresponsefaceagreatersensitivitytomutagenchallenge.Interindividualvariabilityinmutagenorradiationsensitivityandincancersusceptibilitymayalsobetracedbacktopolymorphismsofgenesaffectinge.g.DNArepaircapacity[1].

简介：Amongthemanyspecialfactorsinthespaceenvironment,spaceradiationespeciallyhighenergyheavyionradiationiswidelyregardedasoneofthecrucialfactorsthathazardthehealthandsafetyofastronaut.Itiswellknownthatbiologicaleffectsofradiationaredependentonthelinear-energy-transfer(LET)oftheemergentbeam.HeavyionshavehighLETandcouldinducecomplexandclusteredDNAdamage,whichismoredifficulttoberepairedthanindividuallesionsandisevenirreparable.

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简介：苏科版八年级下册物理教材中，关于影响滑动摩擦力大小的因素的叙述是“在一定范围内，滑动摩擦力的大小与接触面积的大小无关．”其中的“在一定范围内”究竟代表什么意思呢？

简介：本文对圆筒形推拉式磁偶合器的磁力矩,进行了推导,对推导结果进行了分析.