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85 个结果
  • 简介:Thenasogastrictube(NGT)hasbecomeafrequentlyuseddevicetoalleviategastrointestinalsymptoms.Nasogastrictubesyndrome(NTS)isanuncommonbutpotentiallylife-threateningcomplicationofanindwellingNGT.NTSischaracterizedbyacuteupperairwayobstructionduetobilateralvocalcordparalysis.Wereportacaseofa76-year-oldmanwithNTS,inducedbyanindwellinglongintestinaltube.Hewasadmittedtoourhospitalfortreatmentofsigmoidcoloncancer.Heunderwentsigmoidectomytoreleaseabowelobstruction,andhadalongintestinaltubeinsertedtodecompresstheintestinaltract.Hepresentedacutedyspneafollowingprolongedintestinalintubation,andbronchoscopyshowedbilateralvocalcordparalysis.TheNGTwasremovedimmediately,andtracheotomywasperformed.Thepatientwasfinallydischargedinafullyrecoveredstate.NTSbeconsideredinpatientscomplainingofacuteupperairwayobstruction,notonlywithaNGTinsertedbutalsowithalongintestinaltube.

  • 标签: Nasogastric TUBE SYNDROME Nasogastric TUBE LONG
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  • 简介:AbstractAs an innovative in vitro culture model, organoids have been established by cell sorting and subsequent culture in three-dimensional culture systems. Organoids can be derived from induced pluripotent stem cells or organ-restricted adult stem cells. Compared with traditional two-dimensional cell culture models and patient-derived xenograft models, organoids possess long-term genetic stability and can better retain the characteristics of source tissues or organs. These advantages have led to the increased use of ovarian and fallopian tube organoids in various fields of research, including cell differentiation and development, establishment of disease occurrence and progression models, tissue regeneration and reconstruction, individual drug screening, immune cell co-culture, and maternal-fetal medicine. This review briefly summarizes the recent progress in the application of ovarian and fallopian tube organoids in the field of obstetrics and gynecology.

  • 标签: Organoid Personalized Therapy Stem Cell Three-Dimensional Culture
  • 简介:AbstractCilia are microtubule-based filamentous organelles that play a vital role in embryogenesis. Multiple signal transduction pathways are orchestrated by cilia, such as Hedgehog and planar cell polarity signals. Various studies, spanning over last 2 decades, have emphasized the role of cilia-mediated signaling cascades in regulating neural tube patterning and development. Moreover, the deficiency of certain ciliary genes have been reported to cause neural tube defects (NTDs), which are a set of disorders that occur due to perturbation of normal neural tube closure. However, the mechanisms underlying cilia dysfunction resulting NTDs remain unclear. Recent studies have highlighted the association of phosphoinositide signaling with cilia, thereby conferring novel insights into the function of cilia during neural tube development. Here, we have reviewed recent studies on cilia, focusing on the molecular mechanism underlying the involvement of cilia in neural tube development and the role of ciliary disruption in the development of NTDs.

  • 标签: Cilia Sonic hedgehog Phosphoinositide Intra-flagellar transport Neural tube defect
  • 简介:Thechaotictransientsofacurvedfluidconveyingtubesubjectedtoanonlinearfoundationareinvestigated.TheassumptionoftheinextensibilityofthetubeisappliedtoderivethenonlineardifferentialequationofmotionviatheNewtonianapproach,withthedifferentialquadraturemethodusedtodiscretizethecurvedtubemodelinthespatialdomain.Andthenonlineardynamicmotionequationisobtained.Thenumericalanalysisshowsthat,thefinalsteadystatesaresensitivetotheinitialsystemconditionsinalargeparameterregionofthefluidspeed.Thisphenomenonofchaotictransientsisinfrequentforfluidconveyingtubes.

  • 标签: 混沌理论 曲线输送管 瞬时现象 非线性动态特性 DQM
  • 简介:Themethodconsistingofcoldtestandhotsimulatinghasbeenprovedtobereliablefordesigningpermeableele-ments.Thecarbon-magnesiamultiple-tubepermeableele-mentswhichareformedbyisostaticalpressurehavehigherdensity,highheatresistanceandgoodthermoshockresis-tance,Thebrickwork,maintenanceanderosionmeha-nismofpermeableelementswerestudied.Thetehnologyofcombinedblowingwaestablishedbasedonthepeculiari-tiesofsemi-steelrefiningatPanzhihuaIrom&SteelCo.(PZISC).Theservicelifeofpermeableelementsreahed600heats,thatmeansthepermeableelementscanworksynchronitiallywithconverterlining.

  • 标签: 多管可透元素 吹气转炉 氧化镁 C MGO
  • 简介:AnewReynolds-averagedNavier-Stokes(RANS)turbulencemodelisdevelopedinordertocorrectlypredictthemeanflowfieldinadrafttubeoperatingunderpartialloadusing2-Daxisymmetricsimulations.Itisshownthatalthough2-Daxisymmetricsimulationscannotmodelthe3-Dunsteadyfeaturesofthevortexrope,theycangivetheaveragelocationofthevortexropeinthedrafttube.Nevertheless,RANSsimulationsunderpredicttheturbulentkineticenergy(TKE)productionanddiffusionnearthecenterofthedrafttubewherethevortexropeforms,resultinginincorrectcalculationofTKEprofilesand,hence,poorpredictionoftheaxialvelocity.Basedonthisobservation,anewk-εturbulenceRANSmodeltakingintoaccounttheextraproductionanddiffusionofTKEduetocoherentstructuresassociatedwiththevortexropeformationisdeveloped.Thenewmodelcansuccessfullypredictthemeanflowvelocitywithsignificantimprovementsincomparisonwiththerealizablek-εmodel.ThisisattributedtobetterpredictionofTKEproductionanddiffusionbythenewmodelinthedrafttubeunderpartialload.Specifically,thenewmodelcalculates31%moreproductionand46%morediffusionrightattheshearlayerwhencomparedtothek-εmodel.

  • 标签: 轴对称模型 局部荷载 扩散预测 管流 RANS 斯托克斯方程
  • 简介:Elbowdraft-tubesarewidelyusedinlargeandmedium-sizedhydropowerstationsinmanycountries.Duringtheapplication,handlingthesomatotypeofelbowtubeshasbeenfoundchallenging:inordertomaintainthedesignedshapeofdrafttubeandtomeettherequirementofconstructionlofting,theconfigurationofreinforcingbarsandthefabricationoftemplates,thegeometryofelbowtubeshastobeaccuratelycalculatedtodrawengineeringgraphics.Basedonthederivedequationsinthispaper,themotionofelbowtubecurveenvelopeissimulatedbyusingcomputers,whichshowsdirectlythesmoothnessofthecurveandprovidesdynamicsimulationforthestudyandoptimizationofthedesignandconstructionofelbowdrafttubes,alongwiththefrontviewandbottomview.

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  • 简介:为健全试管系统的一个宽带变换器被介绍,它联合纵的变换器和类IVflextensional变换器在低频率改进性能并且拓宽工作乐队。相等的电路被获得并且过去常分析在纵的变换器和flextensional变换器之间的联合机制。变换器的一个原型在由有限元素方法优化电声的表演以后被开发。在这个变换器刺激的健全试管的站的波浪被学习了,二件声学的材料样品的健全吸收系数用这个健全试管被测量,它证明变换器能满足声学的材料测量的要求,工作乐队从1.4kHz到23kHz。

  • 标签: 测量系统 传感器 宽带 弯张换能器 声学材料 工作频带
  • 简介:Themajorflowphysicsoftheunsteadycondensationinthesubsonicflowsinducedbytheunsteadyexpansionwavesinshocktubewasstudiedinthispaper.Theunsteadycondensationphenomenonwasanalyzedbyusingthetwo-dimensional,unsteady,Navier-Stokesequations,whichwerefullycoupledwithadropletgrowthequation.Thethird-orderTVDMUSCLschemewasappliedtosolvethegoverningequationsystems.Thecomputationalresultswerecomparedwiththepreviousexperimentaldata.Thetime-dependentbehaviorofunsteadycondensationofmoistairinshocktubewasinvestigatedindetails.Theresultsshowthatthemajorcharacteristicsoftheunsteadycondensationphenomenoninshocktubeareverydifferentfromthoseinthesupersonicwindtunnels.

  • 标签: shock tube shock WAVE EXPANSION WAVE
  • 简介:Thehomogeneousnucleationwithsubsequentspontaneouscondensationofwater,pentanol,andethanolvaporsinacarriergasareinvestigatedexperimentallyandtheoreticallyintheexpansionpartofashocktube.TheprecisepressureandMCWmeasurementsgiveadditionalinformationaboutthewetness,sothatthenucleationandcondensationrateswhicharecloselycoupledforstrongerexpansionratesaredetermiedmoreaccurately,Predictionsoftheprincipleoftheminimumofentropyproductionarecomparedwithexperimentsperformedforwater,ethanolandpentanolatdifferentpressures.

  • 标签: 蒸汽 冷凝冲击 冲击管 数字模拟
  • 简介:Thispaperintroducesamethodforstudyingcondensationheattransferinsideatubeinmicrogravityenvironment.Themodelassumeslaminarflowinthecondensatefilmandanannularflowpattern,Thelocalheattransfercoefficinetisthecalculatedbygravitationalacceleration,g,from0to9.8m/s^2.themodelwastestedindirectlybymeasuringcondensationheattransferinsideaverticaltubeinanormalgravityenvironmentthroughexperiments.

  • 标签: 冷凝器 热传输 环流
  • 简介:Anexperimentalstudywascarriedouttoinvestigatetheinfluenceofdoubletwisted-tapeinserts(DTs)inmicro-fintubes(MFs)onheattransfer,frictionfactorandthermalperformancefactorcharacteristicsofthecompounddevicesinthefollowingconfigurations:(1)twistedtapesactedinthesamedirection(forco-swirl)whileMFandtwistedtapesactedinthesame(parallel)direction(MF-CoDTs:P),(2)twistedtapesactedinthesamedirection(forco-swirl)whilemicro-fintubeandtwistedtapesactedinoppositedirections(MF-CoDTs:O)and(3)twistedtapesactedinoppositedirectionsforcounterswirl(MF-CDTs).TheMFaloneandtheMFequippedwithasingletwistedtapeinparallel/oppositearrangementwerealsoconsideredforcomparison.TheexperimentswereconductedfortheflowswiththeReynoldsnumbersbetween5650and17000,underuniformheatfluxcondition.TheexperimentalresultsindicatethatMF-CDTsinducestrongerswirl/turbulenceflow,resultinginhigherheattransferrate,frictionfactorandthermalperformancefactorthanothercombineddevices.ThethermalperformancefactorsassociatedwiththeuseofMF-CDTswerefoundtobehigherthanthoseassociatedwiththeusesofMF-CoDTs:P,MF-CoDTs:OandMFaloneupto9.3%,6.5%and56.4%,respectively.TheempiricalcorrelationsdevelopedusingthepresentexperimentaldatafortheNusseltnumber,frictionfactorandthermalperformancefactorarealsoreported.

  • 标签: 传热特性 微肋管 扭带 配备 性能系数 实验性
  • 简介:基于精力保存关系,包括不稳定性范围的Rijke试管的非线性的thermo声学的效果,浸透过程和更高的泛音模式被调查。与在外部流动和一个Rijke试管的内部空间之间联合,自我刺激的摆动的声学的特征被模仿。试验性的学习也被执行,结果与从模拟的那些相比。弄歪的非线性的因素声学的波形失真被分析。从结果,嘴插头的变化尺寸在边界改变声学的阻抗,这被看见,并且导致非线性的效果的减小。结果证明自我刺激的摆动的模式能被更高的泛音的位置影响。在大振幅摆动,在Rijke试管以内的压力波浪的失真能被声学的损失在嘴上由于旋涡导致。波形失真能被嘴的收缩避免,这被发现。

  • 标签: RIJKE管 非线性因素 声学特性 自激振荡 高次谐波 波形失真
  • 简介:Amodelwasestablishedtopredictcondensationheattransfercoefficientonhorizontalrectangularfinnedtube.Drop-Offzoneatthetubebottomwasconsideredanddetermined,theknownHonda(andOwen)expressionofretentionanglewasalsomodifiedasaresultofconsideringdrop-offzone.Heatfluxonfintipsintheunfloodedregion,finflanks,finspacingsandfintipsinthefloodedregionwereanalyzedrespectively.COndensationonfintipsinemphasizedbyconsideringthevariationoffilmthicknessalongcircumferenceaswellashorizontally.FInefficiencywasconsideredincalculation.Thepredictionresultswerecomparedwithseveralresearchers'experimentaldataforthreekindsofworkingfluidsonsevendifferenttubegeometriesandforvarioustemperaturedifferences,Thesedataunderabout60testconditionswerepredictedwithdiscrepancyof±10%.PredictionbythepresentmodelforsteamandR-113condensationwerecomparedwithpreviousmodels.

  • 标签: 冷凝器 单水平矩形散热管 设计模型
  • 简介:Inthispaper,thephenomenononcollapsibletubedisplacementoscillation,anewbehaviorofthecollapsibletubepuisatileflowhasbeenstudied.Theexperimentsshowthatthecollapsibletube,inwhichtheflowisperiodicpuisatileintheupstream,willoscillateasasimplesupportedbeamwhenitiscollapsedtocertainextent,andthatifthetubeiscollapsedcontinue,thisoscillationwilltendtoweakandcompletelydisappearlastly.Ananalyticalmodelcorrespondingtothecollapsibletubedisplacementoscillationanditsgovernedequationsaresetupfromtheexperimentbackground.Byanalysingthemodelandsolvingtheequations,thecollapsibletubedisplacementoscillationpatternandtheoscillationoccurringordisappearingcriterionareobtained.Theresultspredictedbythisstudyareinagreementwiththoseobservedfromexperimentphenomena.

  • 标签: OSCILLATION UPSTREAM UNSTEADY governed disappear criterion
  • 简介:FibersuspensionsflowthroughatubecontainingasphereinthediluteandconcentratedregimesissimulatednumericallywiththeLatticeBoltzmannMethod(LBM).Thenumericalresultsoffiberorientationdistributionbasedonastatisticalschemeareobtainedandagreequalitativelywiththeexperimentalonesfortheflowthroughaparallelplatechannelcontainingacylinder.Theresultsshowthatthesphereinthetuberesultsinachangeinthefiberorientationdistributiondownstreamofthespherealongtheflowandtransversedirections.Theinfluencesofthesphereonthefiberorientationdistributionaremoresignificantfortheconcentratedsuspensionsthanforthediluteone.Theeffectoftheinitialfiberorientationsonthefiberorientationdistributionissignificantupstreamofthespherebutsmalldownstreamofthesphere.

  • 标签: 纤维取向分布 悬浮液 球体 格子玻尔兹曼方法 管流 流动方向
  • 简介:Anexperimentalinvestigationofananosecondpulseddielectricbarrierdischargeinatmosphericairispresented.Inthesetupaquartztubewasinsertedbetweentheconeandplaneelectrodesinthedirectionparalleltotheelectricfield.Itwasshownthattheappearanceandpropertyofthedischargeweresensitivetothesizeandthepositionofthequartztube.Whenthetubewasplacedonthegroundedplaneelectrode,thedischargeintensitywasfoundtoimprovegraduallywiththeincreaseinthediameterofthequartztube.Furthermore,withanappropriatedistancebetweenthebottomedgeofthequartztubeandtheplaneelectrode,thedischargetendedtoexhibitbetterperformanceingeneratinghomogeneousdiffusiveplasma.Thepossiblemechanismisdiscussed.

  • 标签: 脉冲放电 纳秒脉冲 石英管 外观 作者 空气