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234 个结果
  • 简介:Theorganizationofthecanonicalgeneticcodeneedstobethoroughlyilluminated.Herewereorderthefournucleotides-adenine,thymine,guanineandcytosine-accordingtotheiremergenceinevolution,andapplytheorganizationalrulestodevisinganalgebraicrepresentationforthecanonicalgeneticcode.Underaframeworkofthedevisedcode,wequantifycodonandaminoacidusagesfromalargecollectionof917prokaryoticgenomesequences,andassociatetheusageswithitsintrinsicstructureandclassificationschemesaswellasaminoacidphysicochemicalproperties.Ourresultsshowthatthealgebraicrepresentationofthecodeisstructurallyequivalenttoacontent-centricorganizationofthecodeandthatcodonandaminoacidusagesunderdifferentclassificationschemeswerecorrelatedcloselywithGCcontent,implyingasetofrulesgoverningcompositiondynamicsacrossawidevarietyofprokaryoticgenomesequences.Theseresultsalsoindicatethatcodonsandaminoacidsarenotrandomlyallocatedinthecode,wherethesix-folddegeneratecodonsandtheiraminoacidshaveimportantbalancingrolesforerrorminimization.Therefore,thecontent-centriccodeisofgreatusefulnessindecipheringitshithertounknownregularitiesaswellasthedynamicsofnucleotide,codon,andaminoacidcompositions.

  • 标签: 组织动力学 遗传密码 氨基酸组成 基因组序列 代数表示 分类方案
  • 简介:Geneticdefectsareoneofthemostimportantetiologiesofseveretoprofoundsensorineuralhearinglossandplayanimportantroleindeterminingcochlearimplantationoutcomes.Whilethepathogenicmutationtypesofanumberofdeafnessgeneshavebeencloned,thepathogenesismechanismsandtheirrelationshiptotheoutcomesofcochlearimplantationremainahotresearcharea.Theauditoryperformanceisconsideredtobeaffectedbytheetiologyofhearinglossandthenumberofsurvivingspiralganglioncells,aswellasothers.Currentresearchadvancesincochlearimplantationforhereditarydeafness,especiallytherelationshipamongclinic-types,genotypesandoutcomesofcochlearimplantation,willbediscussedinthisreview.

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  • 简介:竹子是一种非常重要的非木质林产品。用途很广泛。它在纸浆造纸工业中用途甚广。竹子的需求增长很快。树木改良技术可填补空白。优良植株可提高竹子产量,来满足不同规模的定植苗,选择丛生可产出多株繁殖。常规的体细胞杂交最初也能诱导理想的基因。采取原地和异地保护的方法,对竹子生物多样性加以保护。

  • 标签: 竹子 遗传改良 无性繁殖 生物多样性保护 体细胞杂交
  • 简介:Thepaperdescribestheproposedmodelsofdiamondformationbothinmeteoritesandinkimberliteandlamproitebodies.metamorphiccomplexesandexplosive-ringstructures('astroblemes'),Thediamonddistributioninmeteorites(chondrites,ironmeteoritesandureilites)isrestrictedtotaente-kamasitephase.Thediamondgenerationhereistiedupwiththefirststageofevolutionoftheplanets,Thisstageischaracterizedbyhighpressureofhydrogen.leadingtotheformationoftheplanetenvelope,Thesecondstageofplanetevolutionbeganwiththeprogressiveimopoverishmentoftheiratmospheresinhydrogenduetoitspredominantemissionintothespaceandtoprogressivedevelopmentofoxidativeconditions.Themodelappearstohaveprovedtherelictnatureofdiamondmineraolizationinmeteorites.Diamondandotherhigh-pressureminerals(its'satellites')werecrystallizedwithoutanyexceptionintheearlyintratelluricstagesofperidotiteandeclogite-pyroxenitemagmaevolutionjustbeforethemagmaintrusionintothehigherlevelsofthemantleandcrustwherediamondisnotthermodynamicallystable,Theultramaficintrusivebodies(bearingrichrelictdiamonds)inthedaseofaplatformpaaeartobethesubstratafortheformationofkimberlite-lamproitemagmachambersasaresultofmagmaticreplacement.Themodelexplainsthepolyfacialnatureofdiamondiferouseclotgites,pyroxenitesandperidotitesanddiscussestheprocessofinheritanceoftheirdiamondmineralizationbykimberlitesandlamproites.Dimondoproductivityofmetamorthiccomplexesisoriginatedbytheinheritanceoftheirdiamondsfromtheabove-mentionedprimarydiamondiferousrocks.Largediamondiferousexplosive-ringstructureswereformedbyhigh-energyendogenicexplosionoffluidwhichcamefromtheEarth'score.Thishighenergydiffersendogenicimpactogenesisfromexplosivevolcanism.Itproceedsatveryhightemperaturetocreatediaplecticgalsses(monomineralpseudomorphs)-theproductofisochoricmelting,atthepressurehighenoughforth

  • 标签: 金刚石矿床 成矿作用 成因类型 高压作用 榴辉岩
  • 简介:这被相信在RNA世界上运作(ribozymes)并且参考(riboscripts)RNA分子被创造与仅仅三(腺苷,uridine,和海鸟粪正弦)并且二(腺苷和uridine)nucleosides,分别地以便遗传密码开始了不复杂。随后发展能剪贴自己和riboscripts的Ribozymes对严密编辑善于接受(到肌甙的腺苷);RNA分子的集中的多样化塑造了能够polymerizing氨基酸的新奇细胞的机械—细胞的大楼材料的一种新类型永久。开始,遗传密码,编码七氨基酸,仅仅被创造区分嘌呤和嘧啶;它以后以编码12,15,和20的一个逐步的方法被扩展通过从它的角色的鸟嘌呤的消除的氨基酸作为运作的信号并且通过胞嘧啶的招募。因此,遗传密码的成熟也与一致与(1)从初发的翻译机械的aminoacyl-tRNA(AARS)的离开,(2)由DNA的参考RNA的代替,并且(3)AARS的合作进化和他们的血缘的tRNAs。这个模型由DNA预言做RNA的分子的机制,由蛋白质的细胞的过程,和参考利用的渐渐的代替。

  • 标签: 基因代码 密码 氨酰-TRNA合成酶 GC库容
  • 简介:Epithelialovariancancerrepresentsthemostlethalgynecologicalmalignancyinthedevelopedworld,andcanbedividedintofivemainhistologicalsubtypes:highgradeserous,endometrioid,clearcell,mucinousandlowgradeserous.Thesesubtypesrepresentdistinctdiseaseentities,bothclinicallyandatthemolecularlevel.Molecularanalysishasrevealedsignificantgeneticheterogeneityinovariancancer,particularlywithinthehighgradeseroussubtype.Assuch,thissubtypehasbeenthefocusofmuchresearchefforttodate,revealingmolecularsubgroupsatboththegenomicandtranscriptomiclevelthathaveclinicalimplications.However,stratificationofovariancancerpatientsbasedontheunderlyingbiologyoftheirdiseaseremainsinitsinfancy.Here,wesummarizethemolecularchangesthatcharacterizethefivemainovariancancersubtypes,highlightpotentialopportunitiesfortargetedtherapeuticinterventionandoutlineprioritiesforfutureresearch.

  • 标签: 分子水平 遗传异质性 卵巢癌 基础生物学 临床意义 浆液性
  • 简介:Thispaperpresentsanovelapproachtofeaturesubsetselectionusinggeneticalgorithms.Thisapproachhastheabilitytoaccommodatemultiplecriteriasuchastheaccuracyandcostofclassificationintotheprocessoffeatureselectionandfindstheeffectivefeaturesubsetfortextureclassification.Onthebasisoftheeffectivefeaturesubsetselected,amethodisdescribedtoextracttheobjectswhicharehigherthantheirsurroundings,suchastreesorforest,inthecoloraerialimages.Themethodologypresentedinthispaperisillustratedbyitsapplicationtotheproblemoftreesextractionfromaerialimages.

  • 标签: 遗传算法 特征提取 分类结构 图像提取 交叉 变化
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  • 简介:Anaudiorecoveringmethodofspread-spectrumhiddeninformationisproposedbasedongeneticalgorithm.Inthismethodtheembeddedsequencelengthisconfirmedfirstly,thenthebestestimatedsequencewiththeconfirmedlengthisgotbygeneticalgorithm,finallytheconfidentialmessagehiddeninstego-audiocanberecovered.Usingthisapproach,thehiddeninformationcanberecoveredwithoutanyinformationfromthetransmitter.ThepresentedmethodhasbeenimplementedonPC,andtheexperimentalresultsshowthattheaveragerecoveringcorrectrateishigherthan90%.

  • 标签: 隐藏信息 遗传算法 音频 恢复方法 MED 嵌入式
  • 简介:Inheritedcardiomyopathiesaremajorcausesofmorbidityandmortalityandincludeagroupofcardiacdisorderssuchashypertrophiccardiomyopathy(HCM),dilatedcardiomyopathy,arrhythmogenicrightventriculardysplasia/cardiomyopathy(ARVD/C),leftventricularnoncompaction(LVNC),andrestrictivecardiomyopathy(RCM).Thesediseaseshaveasubstantialgeneticcomponentandpredisposetosuddencardiacdeath.Sincethefirstgenewasidentifiedasadisease-causinggeneforHCMovertwodecadesago,morethaneightygeneshavebeenidentifiedtobeassociatedwithinheritedcardiomyopathiesandgenetictestinghasbecomeprevalentinmakingclinicaldiagnosis.Withtheadventofnext-generationsequencingtechnology,geneticpaneltestingofinheritedcardiomyopathieshasbecomefeasibleandcostefficient.Inthisreview,wesummarizetheindividualcardiomyopathieswiththeemphasisoncardiomyopathygeneticsandgenetictesting.

  • 标签: GENETICS HCM DCM RCM ARVD/C LVNC
  • 简介:Thegeneticimprovementofwoodpropertiesisoneoftheimportantmeasuresofimprovingwoodquality.Toachievethat,forestryandwoodscientistshavedoneagreatdealofresearchinexpectationtoproducemorehigh-qualitywood.Thepapersummarizestheresearchesongeneticvariationandgeneticcorrelationofwoodpropertiesandproposestheprospectstoconductthegeneticimprovementofwoodproperties.

  • 标签: 木质材料 遗传变异 遗传相关 木材
  • 简介:RNaseMRPRNA是处理的RNasemitochondrialRNA(MRP)的RNA子单元涉及处理事件的多重细胞的RNA的酶建筑群。RNaseMRPRNA基因(RMRP)上的变化引起后退地继承的发展混乱,软骨头发发育不全(CHH)。遗传型(RMRP变化)的关系,RNaseMRPcomplex的RNA处理缺乏,和CHH和另外的骨胳的发育异常的显型还有待于被探索。

  • 标签: 核糖核酸酶线粒体加工 RNASE MRP RNA 遗传病 软骨-毛发发育不全
  • 简介:ThepresentsituationofforesttreegeneticgermplasmresourcesresearchandconservationinChinaisintroducedwhichincludingthebackground,decision-makingofconservationstrategiesandprinciples,theplanofareadivisionandtreespeciesclassification,thesamplestrategyofgermplasmconservation,theadvancesinconservationpatternandrelatedtechnologiesresearch,theachievementsofgermplasmconservationandutilizationinChina,andtheproblemstobesolved.Therecentachievementsa...

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  • 简介:Thecross-fertilizationbetweenartificialintelligenceandcomputationalfinancehasresultedinsomeofthemostactiveresearchareasinfinancialengineering.Onedirectionistheapplicationofmachinelearningtechniquestopricingfinancialproducts,whichiscertainlyoneofthemostcomplexissuesinfinance.Intheliterature,whentheinterestrate,themeanrateofreturnandthevolatilityoftheunderlyingassetfollowgeneralstochasticprocesses,theexactsolutionisusuallynotavailable.Inthispaper,weshallillustratehowgeneticalgorithms(GAs),asanumericalapproach,canbepotentiallyhelpfulindealingwithpricing.Inparticular,wetesttheperformanceofbasicgeneticalgorithmsbyusingittothedeterminationofpricesofAsianoptions,whoseexactsolutionsisknownfromBlack-Scholesoptionpricingtheory.Thesolutionsfoundbybasicgeneticalgorithmsarecomparedwiththeexactsolution,andtheperformanceofGAsisewluatedaccordingly.Basedontheseewluations,somelimitationsofGAsinoptionpricingareexaminedandpossibleextensionstofutureworksarealsoproposed.

  • 标签: 遗传算法 选择定价 金融学 机器学习
  • 简介:Thispaperproposesasupervisedtraining-testmethodwithGeneticProgramming(GP)forpatternclassification.Comparedandcontrastedwithtraditionalmethodswithregardtodeterministicpatternclassifiers,thismethodistrueforbothlinearseparableproblemsandlinearnon-separableproblems.Forspecifictrainingsamples,itcanformulatetheexpressionofdiscriminatefunctionwellwithoutanypriorknowledge.Atlast,anexperimentisconducted,andtheresultrevealsthatthissystemiseffectiveandpractical.

  • 标签: GENETIC PROGRAMMING pattern CLASSIFIERS DISCRIMINATE function
  • 简介:Eachcomponentofthehumanearperformsaspecificfunctioninhearing.Theactualprocessofsoundtransductiontakesplaceintheauditoryportionoftheinnerear,thefluid-filledcochlea.Inthecochlea,thesensitivityandefficiencyofsensoryapparatustoconvertmechanicalenergyintoneuralactivity,largelydependsonthefluidicandionicenvironment.Inthelateralwallofcochlea,thesecretoryepitheliumstriavascularisplaysanimportantroleinthemaintenanceoffluidicandionichomeostasis.Avarietyofgenemutationsdisturbsthecochlearhomeostasisandsubsequentlyleadstohearingimpairment.Thereviewcoversseveralaspectsofcochlearhomeostasis,fromcochlearfluidandthefunctionalroleofstriavascularis,cochlearK+recyclinganditsmolecularsubstratestogeneticdeafnesswithabnormalcochlearhomeostasis.

  • 标签: HOMEOSTASIS mechanical energy maintenance molecular inner
  • 简介:Thecodontableforthecanonicalgeneticcodecanberearrangedinsuchawaythatthecodeisdividedintofourquartersandtwohalvesaccordingtothevari-abilityoftheirGCandpurinecontents,respectively.Forprokaryoticgenomes,whenthegenomicGCcontentincreases,theiraminoacidcontentstendtoberestrictedtotheGC-richquarterandthepurine-contentinsensitivehalf,whereallcodonsarefourfolddegenerateandrelativelymutation-tolerant.Conversely,whenthegenomicGCcontentdecreases,mostofthecodonsretracttotheAU-richquarterandthepurine-contentsensitivehalf;mostofthecodonsnotonlyremainencodingphysicochemicallydiversifiedaminoacidsbutalsovarywhentransversion(betweenpurineandpyrimidine)happens.Aminoacidswithsixfold-degeneratecodonsaredistributedintoallfourquartersandacrossthetwohalves;theirfourfold-degeneratecodonsareallpartitionedintothepurine-insensitivehalfinfavoriteofrobustnessagainstmutations.Thefeaturesmanifestedinthere-arrangedcodontableexplainmostoftheintrinsicrelationshipbetweenproteincodingsequences(theinformationalcontent)andaminoacidcompositions(thefunctionalcontent).Therenovatedcodontableisusefulinpredictingabundantaminoacidsandpositioningtheaminoacidswithrelatedordistinctphysicochem-icalproperties.

  • 标签: 遗传学 遗传密码 密码子 嘌呤