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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：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：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：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：用解析法讨论两质点的二维弹性碰撞,得到并验证了当入射质点的质量大于靶质点的质量时,入射质点的散射角存在最大值限制,而当入射质点质量小于靶质点质量时,该限制条件消失;并且当两质点质量相等时,碰撞后两质点运动互相垂直。

简介：本文讨论了无像差再现像存在的条件及不失真的条件，并具体指出球面参考光形成的菲涅耳全息图可有四个既无像差又不失真的再现像。总结出成像的规律便于人们真实地再现原物。

简介：推导了光线在光锥中传播的轨迹方程，利用Matlab进行仿真分析，得到了平行光和杂散光入射光锥后的传播情况。结果表明，光锥对大入射角的平行光的聚集能力较好，对杂散光会聚增益较小，在非视线光通信中只适宜作为不同光学元件的结合部。

简介：从电子在电磁场中的狄拉克方程出发,得出电子在电磁场中波函数,分析磁矢热A引起的电子概率波的相移,结果表明:影响电子波函数的相位变化不是B而是A(x),即有一个额外相因子附加在电子概率波上,进而通过量子干涉出现图样的位移。结论是A—B效应的存在说明磁场的物理效应不能完全用B描述,而是附加在电子概率波上的相因子。

简介：一、浮力概念例1关于物体受到的浮力，下列说法中正确的是（）A.漂浮在水面的物体比沉在水底的物体受到的浮力大B.物体排开水的体积越大受到的浮力越大C.没入水中的物体在水中的位置越深受到的浮力越大D.物体的密度越大受到的浮力越小