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  • 简介:Asatypicaloscillatingchemicalreaction,studiesoftheBelousov-Zhabotinskyreactionhavenotonlyyieldedimportantresultstoprovideinsightstomanykineticandthermodynamicproblems,butalsoprovidedsuggestivemodelsforanumberofimportantbiologicalprocesses.NowtheBZreactionhasbecomeausefulexperimentalmodelforstudyingnonlinearphenomenaindistributedsystems.WecarriedoutasystematicstudyoftheinfluencefactorsontheBZreactioninaclosedsystem,andsomenewobservationsarereportedhereforthefirsttime.

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  • 简介:ComparisonsintheratesofstomachandcoloncancerbetweencountriesoftheEastandthoseoftheWestsuggestthatdietaryfactorsplayasignificantroleincarcinogenesisofthegastrointestinaltract.However,ithasbeendifficulttoclarifywhichofthemanyfactorsthatinfluencecarcinogenesisareinfactalteredbydiet.Geneticdeterminants,dietaryhabits,

  • 标签: 饮食因素 发病机理 胃肠疾病 结肠癌 肿瘤 致癌作用
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  • 简介:Abstract:Thecrackleofriceemergesfrequentlyduringdryingfromheatingpower.Variousfactorsaffectingricecracklewereanalysedanddiscussed.Itshowedthattheeffectivewaytoreducethericedryingcrackleshouldbeproperdryingtemperatureandspeedaswellasrationaldryingtechnology.

  • 标签: 水稻 干燥工艺 裂纹 干燥温度 干燥速度
  • 作者: Zhang Hong Zhou Yu-Jie Zeng Yu-Jie
  • 学科: 医药卫生 >
  • 创建时间:2020-08-10
  • 出处:《中华医学杂志(英文版)》 2020年第13期
  • 机构:Emergency and Critical Care Center, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China,Department of Cardiology, 12th Ward, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing Key Laboratory of Precision Medicine of Coronary Atherosclerotic Disease, Clinical Center for Coronary Heart Disease, Capital Medical University, Beijing 100029, China
  • 简介:AbstractBackground:The detrimental outcomes of right ventricular pacing on left ventricular electromechanical function ultimately result in heart failure, a phenomenon termed pacing-induced cardiomyopathy (PICM) in clinical research. This study aimed to validate prognostic factors that can be used to identify patients with higher susceptibility to progress to the stage of cardiomyopathy before pacemaker implantation.Methods:This observational analysis enrolled 256 patients between January 2013 and June 2016, 23 (8.98%) of whom progressed to PICM after 1 year of follow-up. A Cox proportional hazard model was used to analyze the prognostic factors associated with PICM. Dose-response analysis was used to evaluate the relationship between significant indicators in multifactor analysis and PICM.Results:The mean values of left ventricular ejection fraction before and after pacemaker implantation in 23 patients diagnosed with PICM were 62.3% and 42.7%, respectively. Univariate analysis showed that sex, atrio-ventricular block, paced QRS duration, and ventricular pacing percentage were significantly associated with PICM. In the multivariate analysis, male sex (hazard ratio: 1.20, 95% confidence interval [CI]: 1.09-1.33, P < 0.005), paced QRS duration (hazard ratio: 1.95 per 1 ms increase, 95% CI: 1.80-2.12, P < 0.001), and ventricular pacing percentage (hazard ratio: 1.65 per 1% increase, 95% CI: 1.51-1.79, P < 0.001) were independent prognostic factors associated with the development of PICM. The ventricular pacing percentage and paced QRS duration level defined by the dose-response analysis were positively associated with PICM (P < 0.05).Conclusions:Our findings indicated that paced QRS duration and ventricular pacing percentage were the most sensitive prognostic factors for PICM.

  • 标签: Right ventricular pacing Pacing-induced cardiomyopathy Heart failure
  • 简介:Theprecipitationefficiencyanditsrelationshiptophysicalfactorsareexaminedbyanalyzingatwo-dimensionalcloud-resolvingmodelsimulationduringTOGACOAREinthisstudy.Thebasicphysicalfactorsincludeconvectiveavailablepotentialenergy,water–vaporconvergence,verticalwindshear,cloudratio,seasurfacetemperature,airtemperature,andprecipitablewater.Precipitationefficienciesdonotshowacloserelationshiptoairtemperaturenortoseasurfacetemperaturenortoprecipitablewater.Theprecipitationefficiencyincreasesasthewater–vaporconvergencerateincreasesandverticalwindshearweakens,whereasitdecreasesastheconvectiveavailablepotentialenergydissipatesandanvilcloudsdevelop.

  • 标签: 物理因素 降水效率 对流有效位能 垂直风切变 沉淀效率 空气温度
  • 简介:Basedontheexploratoryspatialdataanalysis(ESDA)techniqueandgeographicinformationsystem(GIS)platform,withstatisticdataofcountiesin2005,thispaperconfirmsthatthereisalargepopulationdensitygapbetweencountiesin2005becausetheGinicoefficientis0.55.Populationdistributiondoesnotchangealotduringthepastdecades,andthesoutheastChinaisstillmuchmoredenselypopulatedthanthenorthwestChina.TheglobalspatialautocorrelationofpopulationdistributionisobviousbecauseMoran'sIscores0.42andlocalspatialautocorrelationispartlysignificant.Climateandelevationarestillthemainnaturalinfluencingfactors.Meanwhileindustrialstructureandtransportationsignificantlyinfluencepopulationdistribution.Differentcombinationsofnaturalfactorshavedifferenteffectsonpopulationdistribution.Foralongterm,climateandterrainfactorstabilityaffectpopulationdistribution.Butitsinfluencewillbeweakenedbyprogressoftechnology.Economicdevelopmentisthemainfactorthatchangespopulationdistributionforashortterm.

  • 标签: 人口分布 ESDA 影响因素 地理信息系统 空间数据分析 中国西北地区
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  • 简介:Thebendingrigidityofsubmergedvegetationiscloselyrelatedwithvegetativedragforce.Thisworkaimsatdeterminingtheeffectsofflowconditionsandcharacteristicsofvegetationonthebendingrigidityofsubmergedvegetation.Basedonthedimensionalanalysismethod,thefactorsinfluencingthebendingrigidityofindividualsubmergedvegetationwereanalyzed.Therelationshipbetweentherelativebendingrigidityanditsinfluencingfactorswasinvestigatedbyexperimentalobservation,andarelativebendingrigidityexpressionforsubmergedvegetationwasobtainedbymeansofmultiplelinearregressionmethod.Theresultsshowthatthesubmergedvegetationhasthreestatesunderdifferentinflowconditions,andtheeachcriticalrelativebendingrigidityofindividualsubmergedvegetationwasdeterminedforthedifferentstatesofsubmergedvegetation.

  • 标签: 抗弯刚度 沉水植物 影响因素 多元线性回归方法 植被特征 三维分析
  • 简介:BackgroundThepurposeofotomicrosurgeryinmoderntimesistoachievecompleteremovalofdisease,whichisthebasisforhearingrehabilitation.Artificialossiclesareimportantforhearingrehabilitation.Oneofthematerialsishydroxyapatitethatactsasossicularreplacementprosthesis(HAprosthesis,PORP&TORP)andiscommonlyusedassubstituteboneinclinics.AlthoughHAprosthesesfeaturegoodbiocompatibility,stabilityandcertainresistancetoinfection,thestructureofthematerialcanbedecomposedandabsorbed.Baseduponanimalexperimentsandclinicalapplication,thisarticleexplorestheinfectivityofHAprosthesesandinfluencingfactors.MaterialsandMethodsHAprostheseswereimplantedinthebullainguineapigs.InfectedHAprostheseswereexaminedunderascanningelectronmicroscope.NinetypatientsimplantedwithHAprostheseswerefollowedformorethan3months.Fivecasesthathadundergonerevisionoperationswerereported.ResultsScanningelectronicmicroscopyshowedthatthenormalcompactstructureshaddisappearedandbecomelooseininfectedHAprostheses,withtheirmicroporesinfiltratedwitheffusion,fibroustissueandinflammatorycells.Asaresult,thenormalceramicstructurewasdecomposedandthemicroporesstructuredisappeared.TheinfectedmesotympanuminthereportedcasesalsoledtoHAinfection.Theshapeandstructureofboneweredestroyed,whichwasvisiblebyvisualexaminationandlightmicroscopy.Theprocessofcholesteatomarecurrencewasalwaysassociatedwithinfection,althoughtheHAprosthesiswassometimesspared.ConclusionWhileHAprosthesisisanti-infectivetosomeextent,long-terminfectionandcholesteatomarecurrencecanleadtodestructionanddecompositionofHAprostheses.Long-terminfectedmiddleearcavity,dysfunctionalEustachiantube,residualandrecurrentcholesteatomaandotherfactorscancausedecompositionofHAprosthesisandresultinhearingloss.

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  • 简介:Inthe2004U.S.presidentialelection,despitewell-divideddomesticopinionsandKerry'sappealingsloganof"ReversingtheTrend,"aslightmajoritystillvotedforGeorgeW.Bushintheend.Itisobviousthat,basedontheauthor'sanalysis,securityagendasuchascounter-terrorismandIraqiissuehascontributedgreatlytothereelectionofMr.Bush.ThisalsoindicatesthatthesecuritypolicyofBush'ssecondtermwillbasicallybeconsistent.

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