简介:Thegravityp-medianmodelisanimportantimprovementtothewidely-usedp-medianmodel.However,thereisstilladebateonitsvalidityinempiricalapplications.Previousstudiesevendoubtthesignificanceofthegravityp-medianmodel.UsingacasestudyoftertiaryhospitalsinShenzhen,China,thisstudyre-examinesthedifferencebetweenthegravityp-medianmodelwiththep-medianmodel,bydecomposingthedifferencebetweenthetwomodelsintogravityruleandvariantattraction.Thisstudyalsoproposesamodifiedgravityp-medianmodelbyincorporatingadistancethreshold.Theempiricalresultssupportthevalidityofthegravityp-medianmodel,andalsorevealthatonlywhentheattractionsofcandidatefacilitylocationsarevariablewillthegravityp-medianmodelleadtodifferentresultswiththep-medianmodel.Thedifferencebetweenthemodifiedgravityp-medianmodelandthegravityp-medianmodelisalsoexamined.Moreover,theimpactsofthedistance-decayparameteranddistancethresholdonsolutionsareinvestigated.Resultsindicatethatalargerdistance-decayparametertendstoresultinamoredisperseddistributionofoptimalfacilitiesandasmalleraveragetraveltime,andasmallerdistancethresholdcanbetterpromotethespatialequityoffacilities.Theproposedmethodcanalsobeappliedinstudiesofothertypesoffacilitiesorinotherareas.
简介:摘要ETC+P智能停车技术是云时代智能停车场管理系统的具体体现,具有少人值守、非现金支付、不停车通行、集中管理等优点。通过对该技术和后台系统的功能的分析,分析该技术的特点和优势,为其他方面的应用提供参考。
简介:目的探讨miR-139-5p对鼻咽癌顺铂(DDP)耐药细胞DDP敏感性的影响及其相关作用机制.方法培养鼻咽癌DDP耐药细胞株HNE1/DDP,分为miR-139-5p组、阴性对照组、DDP组和空白对照组,miR-139-5p组转染miR-139-5p类似物,阴性对照组转染阴性对照序列,DDP组和空白对照组不做转染处理.转染后miR-139-5p组、阴性对照组和DDP组均加入20μmol/LDDP,空白对照组加入培养基,溴化吡啶(PI)单染后流式细胞术检测各组HNE1/DDP细胞凋亡率.采用Westernblot检测HNE1/DDP细胞miR-139-5p组、阴性对照组和空白对照组磷酸肌醇3-激酶(PI3K)、磷酸化(p)-PI3K、蛋白激酶B(Akt)、p-Akt及趋化因子受体4(CXCR4)蛋白的相对表达水平.采用实时荧光定量PCR(qPCR)检测miR-139-5p组、阴性对照组和空白对照组CXCR4mRNA的表达水平.结果空白对照组、DDP组、阴性对照组和miR-139-5p组HNE1/DDP细胞凋亡率分别是6.26%±1.19%、22.43%±3.88%、23.87%±3.21%和40.87%±4.04%,DDP组、阴性对照组和miR-139-5p组细胞凋亡率均高于空白对照组,miR-139-5p组细胞凋亡率高于DDP组和阴性对照组,差异均有统计学意义(P值均〈0.05).Westernblot检测显示,miR-139-5p组p-Akt、p-PI3K、PI3K及CXCR4蛋白的相对表达量均低于空白对照组和阴性对照组,差异均有统计学意义(P值均〈0.01).实时荧光定量PCR检测结果显示,miR-139-5p组中HNE1/DDP细胞CXCR4的mRNA相对表达水平低于空白对照组和阴性对照组,差异均有统计学意义(P值均〈0.01).结论转染miR-139-5p可提高鼻咽癌耐药细胞株HNE1/DDP对DDP的敏感性,其作用机制可能与抑制CXCR4的表达进而调控其下游PI3K/Akt信号通路的活化有关.