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52 个结果
  • 简介:在这个统一模型,我们介绍联合时间的电子声子(t即)和激光脉搏宽度(tp)。为长脉搏,它能代替传统的热传导模型;当时为超短波的脉搏,它能代替标准二温度的模型。作为金目标的一个例子,我们在时间得到电子和离子温度发展的依赖并且由用有限差别的时间域(FDTD)解决热传导方程放方法。它在对试验性的数据的好同意。我们用Saha方程获得脱离的发作的临界溶液温度然后当激光脉搏宽度从毫微秒到飞米第二次规模时,获得激光脱离阀值的理论价值,它与试验性的数据在于很好。

  • 标签: 脉冲激光切除方法 统一模型 电子-声子耦合 超短激光
  • 简介:Atrialfibrillation(AF)isthecommonestcardiacarrhythmia,withsignificantmorbidityandmortality.MorethanhalfofpatientswithAFarestillsymptomaticdespiteadequateanticoagulationandratecontrol.Ifantiarrhythmicdrugsareineffectiveorpoorlytolerated,AFpatientsarethentypicallytreatedwithcatheterablationtorestoresinusrhythm.Inthepast20years,AFablationhasdevelopedfromaspecialized,experimentalprocedureintoacommontreatmentinthecardiovascularfield.Variousablationtechniquesandmappingtechnologieshavebeendescribedandarecontinuingtoevolveforincreasedsafetyandefficacy.Anincompletelistofsuchtechniquesandtechnologieswouldincludefocalandsegmental,circumferentialandlinear,complexfractionatedatrialelectrogram,ganglionatedplexus,focalimpulseandrotormodulation,bodysurfacepotentialmapping–guided,real-timeMRI–guided,cryoballoon,visuallyguidedlaserballoon,radiofrequencyhotballoon,contactforcesensingcatheter,multielectrodecatheter,andhybridablations.ThisreviewexaminesthehistoryofinvasiveAFtreatmentanditsevolutionintocatheterablationbutmainlyfocusesonthediscussionofvariousablationtechniquesandtechnologiesleadingtoourcurrentunderstandingoftheablationtherapyofthismostcommonarrhythmia.

  • 标签: ATRIAL FIBRILLATION CATHETER ablation Invasive CARDIOLOGY
  • 简介:Apreliminaryinvestigationonshort-wavelengthablationmechanismsofpoly(methylmethacrylate)(PMMA)andpoly(1,4-phenyleneetherether-sulfone)(PPEES)byextremeultraviolet(EUV)radiationat13.5nmusingatable-toplaserproducedplasmafromagas-pufftargetatLLG(Gttingen)andat46.9nmbya10HzdesktopcapillarydischargelaseroperatedattheInstituteofPhysics(Prague)ispresented.Ablationofpolymermaterialsisinitiatedbyphotoinducedpolymerchainscissions.TheablationoccursduetotheformationofvolatileproductsbytheEUVradiolysisremovedasanablationplumefromtheirradiatedmaterialintothevacuum.Ingeneral,cross-linkingofpolymermoleculescancompetewiththechaindecomposition.Bothprocessesmayinfluencetheefficiencyandqualityofmicro(nano)structuringinpolymermaterials.WavelengthisacriticalparametertobetakenintoaccountwhenanEUVablationprocessoccurs,becausedifferentwavelengthsresultindifferentenergydensitiesinthenear-surfaceregionofthepolymerexposedtonanosecondpulsesofintenseEUVradiation.

  • 标签: EUV ablation ORGANIC polymer photo-erosion MECHANISMS
  • 简介:AbstractObjective:The aim of the study was to investigate the pregnancy outcomes and possible influencing factors concerning complicated monochorionic (MC) multiple pregnancies undergoing selective fetal reduction using radiofrequency ablation (RFA).Methods:This retrospective cohort study included 54 women with complicated MC multiple pregnancy who underwent selective fetal reduction using RFA at the Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region from January 2015 to March 2020. According to the indications for RFA, the 54 women were divided into three groups: complex complications (n = 30), structural anomalies (n = 18), and triplet pregnancy (n = 6). According to the gestational age for RFA, all patients were divided into three groups: 16-19+6 weeks (n = 17), 20-23+6 weeks (n = 17), and 24-26+6 weeks (n = 20). We analyzed the pregnancy outcomes (including the overall survival rate (OSR), gestational age at delivery, birth weight of newborns) and postoperative complications such as miscarriage, and intrauterine fetal death (IUFD) according to the indications and gestational age of reduction by using suitable statistical testing.Results:The OSR was 83.3% (45/54). The mean ± standard deviation (SD) of gestation at the time of reduction was 21.6 ± 3.2 weeks. The GA at delivery was 34.0(32.0,37.5) weeks. The mean ± SD of newborns’ birth weight was 2118 ± 685 g. The overall rates of miscarriage, PROM, and IUFD were 9.3% (5/54), 7.4% (4/54), and 7.4% (4/54), respectively. According to the indications for reduction, the OSR for complex complications, structural anomalies, and triplet pregnancy groups were 83.3% (25/30), 83.3% (15/18), and 83.3% (5/6), respectively. Statistically significant differences were only found in the mean birth weight among the three groups (P < 0.05). No significant difference was found in the rate of miscarriage, and mean gestation at delivery among the three groups (P > 0.05). In the group with complex complications, the OSR of twin-to-twin transfusion syndrome, selective intrauterine growth restriction, twin reversed arterial perfusion sequence, and twin anemia polycythemia sequence were 66.7% (6/9), 93.3% (14/15), 80.0% (4/5), and 100.0% (1/1), respectively, with no significant difference among these groups (P > 0.05). According to the gestational age of reduction, the OSRs among the three groups were 82.4% (14/17), 76.5% (13/17), and 90.0% (18/20), respectively, and the rate of miscarriage, IUFD, and mean gestation age at delivery among these groups showed no significant difference (P > 0.05).Conclusion:Selective fetal reduction by RFA is an important treatment method for complicated MC multiple pregnancy, although it may lead to complications like miscarriage, and IUFD. The indication of reduction seems to affect the pregnancy outcome. An optimal treatment plan should be selected according to the patient’s conditions in clinical practice.

  • 标签: Twins Monochorionic pregnancies Fetal reduction Radiofrequency ablation Pregnancy outcomes Influencing factors
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  • 简介:Atrialfibrillation(AF)isthemostcommoncardiacarrhythmiaaffectingmillionsofpeopleworldwidewithincreasingincidenceandprevalence.RadiofrequencycatheterablationhasevolvedasthetreatmentofchoiceforbothparoxysmalandpersistentAF.Severalstudieshavebeenreportedoncatheterablationasthefirst-linetreatmentforparoxysmalAFanddifferentstrategiesforpersistentAF.Newtechnologiessuchascontact-forcesensingcathetersandcryoballoonhavebeenrecentlyusedandtheprocedurecarriestheriskofcomplicationslikehematoma,arteriovenousfistula,cardiactamponade,pulmonaryveinstenosis,atrio-esophagealfistulaanddeath.

  • 标签: ATRIAL FI brillation CATHETER ablation major
  • 简介:Atrialfibrillation(AF)isthemostcommonsustainedcardiacrhythmdisturbanceinclinicalpractice,increasinginprevalencewithage.CurativetreatmentofAFwithcatheterablationisnowalegitimateoptionforanumberofpatients.ThedominantablationforAFmainlyconcentratesonpulmonaryveins(PVs)orcomplexfragmentatrialelectrograms(CFAEs).However,theoptimalapproachforablationofAFarousedsomecontroversy.ThebulkoftheevidencesuggeststhattheintrinsiccardiacautonomicnervoussystemmaycontributetotheformationofrapidfiringfromthePVsitesornon-PVsitesandCFAEs,andplayacriticalroleintheinitiationandmaintenanceofAF.WehypothesizedthatganglionatedpleximaybeanidealstrategyforAFablation.

  • 标签: 房颤 理想 自主神经系统 心脏节律 临床实践 最佳方法
  • 简介:Usingmoleculardynamics(MD)methodscombiningwithtwo-stepradiationheatingmodel,themechanismsofablationandthethermodynamicstatesatNisurfaceunderfemtosecondlaserirradiationareinvestigated.Simulationresultsshowthatthemainmechanismsofablationareevaporationandtensilestressesgeneratedinsidethetarget.Thevelocityofstresswaveispredictedtobenearlyequaltosoundvelocity.Theratesofablationatdifferentfluencesobtainedfromsimulationsareingoodagreementwithexperimentaldata.Superheatingphenomenonisalsodiscovered.

  • 标签: 毫秒激光器 金属切割 分子力学 仿真研究
  • 简介:TheisotopeeffectsofablationprocessesinfusionplasmaforfivecombinationsofsolidisotopichydrogenicpelletsH2,HD,D2,DT,T2havebeenfirsttimestudied.Theresuitsshowthatthemodificationscausedbyisotopeeffectsforpelleterosionspeedsrangefrom1forhydrogenpelletdownto0.487fortritiumpelletandarenotnegligibleinablationratecalculations.Theseeffectsleadtodeepermassdepositionandimprovedcorefuelingefficiency.

  • 标签: 同位素效应 消融率 组合靶丸 国际热核聚变堆 芯部加料
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  • 简介:APRELIMINARYANALYSISFORTHERMODYNAMICMODELOFTISSUEHEATINGDURINGRADIOFREQUENCYABLATIONAPRELIMINARYANALYSISFORTHERMODYNAMICMODEL...

  • 标签: 临床应用 射频消融 心血管 监控 技术 功率
  • 简介:BackgroundAmongpatientsundergoingmitral-valvesurgery,30to50%presentwithatrialfibrillation,whichisassociatedwithreducedsurvivalandincreasedriskofstroke.Surgicalablationofatrialfibrillationhasbeenwidelyadopted,butevidenceregardingitssafetyandeffectivenessislimited.MethodsWerandomlyassigned260patientswithpersistentorlong-standingpersistentatrialfibrillationwhorequiredmitral-valvesurgerytoundergoeithersurgicalablation(ablationgroup)ornoablation(controlgroup)duringthemitral-valveoperation.Patientsintheablationgroupunderwentfurtherrandomizationtopulmonary-veinisolationorabiatrialmazeprocedure.Allpatientsunderwentclosureoftheleftatrialappendage.Theprimaryendpointwasfreedomfromatrialfibrillationatboth6monthsand12months(asassessedbymeansof3-dayHoltermonitoring).ResultsMorepatientsintheablationgroupthaninthecontrolgroupwerefreefromatrialfibrillationatboth6and12months(63.2%vs.29.4%,P<0.001).Therewasnosignificantdifferenceintherateoffreedomfromatrialfibrillationbetweenpatientswhounderwentpulmonary-veinisolationandthosewhounderwentthebiatrialmazeprocedure(61.0%and66.0%,respectively;P=0.60).One-yearmortalitywas6.8%intheablationgroupand8.7%inthecontrolgroup(hazardratiowithablation,0.76;95%confidenceinterval,0.32to1.84;P=0.55).Ablationwasassociatedwithmoreimplantationsofapermanentpacemakerthanwasnoablation(21.5vs.8.1per100patient-years,P=0.01).Therewerenosignificantbetween-groupdifferencesinmajorcardiacorcerebrovascularadverseevents,overallseriousadverseevents,orhospitalreadmissions.ConclusionsTheadditionofatrialfibrillationablationtomitral-valvesurgerysignificantlyincreasedtherateoffreedomfromatrialfibrillationat1yearamongpatientswithpersistentorlong-standingpersistentatrialfibrillation,buttheriskofimplantationofapermanentpacemakerwasalsoincreased

  • 标签: 外科治疗 二尖瓣 颤动 心房 手术 安全性
  • 简介:ThispaperisconcernedwithanoptimalcontrolproblemofanablationtranspirationcoolingcontrolsystemwithStefan-Signoriniboundarycondition.Theexistenceofweaksolutionofthesystemisconsidered.TheDubovitskiiandMilyutinapproachisadoptedintheinvestigationofthePontryagin'smaximumprincipleofthesystem.Theoptimalitynecessaryconditionispresentedfortheproblemwithfixedfinalhorizonandphaseconstraints.

  • 标签: 理想控制 最大原则 消融蒸发冷却系统 计算机控制
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  • 简介:瞄准:估计联合transcatheter的效果动脉的chemoembolization(不作声)并且在有大hepatocellular癌(HCC)的病人的经皮的乙醇脱离(豌豆)。方法:有unresectable的63个病人的一个总数大HCC被对待与不作声由豌豆列在后面。肿瘤的最大的尺寸从5.3厘米到17.8厘米。幸存率,尖锐效果,毒性和预示的因素被分析。结果:在1,3和5年的累积幸存率是59.4%,28.4%和15.8%,分别地(27.7瞬间的中部的幸存)。肿瘤区域被超过50%在30减少(47.6%)盒子。在有增加的-fetoprotein(法新社)的56种情况中珍视,法新社水平被超过75%拒绝。联合治疗很好通常被容忍。仅仅二个病人从variceal流血死了与治疗联系了。比例的危险建模的艇长证明肿瘤,肿瘤边缘和乙醇剂量的数字是独立预示的因素。结论:联合不作声并且豌豆治疗是为unresectable的一条有希望的途径大HCC。

  • 标签: 结合治疗 肝癌 乙醇 栓塞 化学 评价
  • 简介:Thesurfaceshapeofliquidwateriswellcontrolledduringnanosecondpulselaserablationplasmapropulsion.Inthisstudy,wemeasuredtheeffectoftheshapeonthecouplingcoefficientandthespecificimpulse.Wefoundthatthecouplingcoefficientandspecificimpulsecouldbeoptimizedbyvaryingthesurfaceconvexity.Basedontheanalysisofthesurfaceradiuscurvature,wedemonstratethattheconvexsurfacechangesthelaserfocalpositionstoachievehighefficiency.

  • 标签: 脉冲激光烧蚀 等离子体推进 表面曲率 液态水 推进剂 表面形貌