简介:摘要随着新课程改革的深入,我们的课堂也渐渐地发生着变化,作为一线教师,应该给予学生更多的空间,要跳出备课预设的思路,灵活应变,尊重学生的思考,课堂会因此而变得更加精彩。本文用了两个例子作对比,说明给学生足够的学习空间是具有重要意义的。
简介:研究了调和Dirichlet空间上调和符号的小Hankel算子的乘积,给出了此类小Hankel算子交换性和乘积为零的完全刻画.
简介:DrivenbycuriosityaboutpossibleflightoptionsfortheChang’e-2spacecraftafteritremainsattheSun-EarthL2point,effectiveapproachesweredevelopedfordesigningpreliminaryfuel-optimalnear-Earthasteroidflybytrajectories.Theapproachesincludetheuseofmodifiedunstablemanifolds,gridsearchofthemanifolds’parameters,andatwo-impulsemaneuverfororbitalphasematchingandz-axisbiaschange,andaredemonstratedtobeeffectiveinasteroidtargetscreeningandtrajectoryoptimization.Asteroidflybysareexpectedtobewithinadistanceof2×107kmfromtheEarthowingtotheconstrainedEarth-spacecraftcommunicationrange.Inthiscase,thespacecraft’sorbitalmotionissignificantlyaffectedbythegravitiesofboththeSunandtheEarth,andtherefore,theconceptofthe"heliocentricoscillating-Keplerorbit"isproposed,becausetheclassicalorbitalelementsoftheflybytrajectoriesreferencedintheheliocentricinertialframeoscillatesignificantlywithrespecttotime.Theanalysisandresultspresentedinthisstudyshowthat,amongtheasteroidswhoseorbitsarethemostaccuratelypredicted,"Toutatis","2005NZ6",or"2010CL19"mightbeencounteredbyChang’e-2inlate2012or2013withtotalimpulseslessthan100m/s.
简介:ThaijasminericeKDML105isconsumedaroundtheworld.BKOS,PKOSandTKOSarenewcultivarsproducedfromlow-energyionbeaminductioninKDML105.ThepurposeofthisstudyistocomparethemorphologyandanatomybetweenKDML105andthethreenewcultivars.Seedsofthefourcultivarsweregerminatedandgrowninpotsuntilfloweringphase.Theplants'organswereobservedandthelengthsofculms,ligules,leavesandpaniclesweremeasured.Leafsurfaceareawascalculatedandnumbersofroots,spikeletsandtillerswerecounted.BKOSandPKOShadsignificantlyshorterculmsthanKDML105andTKOS.ThelargestleafareawasfoundinKDML105followedbyTKOS,BKOSandPKOS,respectively.NumbersofrootsandtillersinBKOSandTKOSweresignificantlyfewerthanthoseinKDML105andPKOS.ThenumberofspikeletsperplantinBKOSwasthelowestamongallcultivars.Foranatomicalcomparison,crosssectionsofculmsandrootswereobserved.Allplantshadasimilararrangementoftissues,butthenumberandsizeofcellsweredifferent.Furthermore,longitudinalsectionsofculmsshowedthatthelengthsofepidermalandparenchymacellsweredirectlyrelatedwiththelengthoftheculm.Tocomparetheleaves,bothstomataandepidermalcellswerecountedandthelengthsoftheguardcellsweremeasured.ThelengthsofguardcellsofBKOSandPKOSwereshorter,butthestomataldensityandthestomatalindexweresignificantlygreaterthanthoseofKDML105.ForTKOS,thoughthelengthofguardcellswasshorterthanthatinKDML105,thedifferencewasnotsignificant.However,thestomataldensityandstomatalindexweresignificantlyhigherthanthoseinKDML105.
简介:与植物提取法和化学合成法相比,利用微生物发酵产类胡萝卜素具有很大的优势.本实验以锁掷酵母(Sporidiololuspararoseus)为研究对象.在前期7L发酵罐培养的基础上,对其在30L发酵罐中的发酵工艺条件进行了研究.本实验比较了不同配比的补糖方式、硫酸铵添加方式及通气速率对生物量和类胡萝卜素的影响.确定最适的产类胡萝卜素工艺条件:维持葡萄糖最终浓度为120g/L,初始培养基加入20.83%的葡萄糖,在12h~40h、40h~72h分别补加66.67%、12.50%的葡萄糖;维持硫酸铵最终浓度为5g/L,初始培养基加入40%的硫酸铵,在12h~24h、24h~36h、36h~48h分别均补加20%的硫酸铵;通气量在0h~12h、12h~~40h、40h~72h分别控制在1.0L/min、2.0L/min、2.0L/min.在此条件下,培养72h,其菌体干重达54.60g/L,总类胡萝卜素含量为33.20mg/L.
简介:目的研究HPVL1壳蛋白检测在宫颈上皮内瘤变(CIN)诊断中的临床意义以及对CIN转归的预测价值,探索更加合理有效诊断处理CIN的方案.方法选择在南京大学医学院附属鼓楼医院行官颈HPV-HC2检测阳性的妇女共187例,同时检查TCT、HPVL1壳蛋白检测及宫颈活检,以病理组织结果为金标准进行对照研究,并对其中继续在鼓楼医院治疗并随访的114例妇女行跟踪研究2年.结果(1)根据宫颈活检病理结果分组,CIN1、CIN2、≥CIN3的L1壳蛋白阳性率分别是49.12%、30.00%、20.45%,运用卡方检验,x2=10.437,P=0.015<0.05,有统计学差异CIN1组的L1阳性率大于其他各组,而其他组别的L1阳性率之间均无统计学差异,CIN2和CIN3合并与C1NI组进行卡方检验,x2=9.443,P=0.002<0.05,有统计学差异.(2)在2年随访结果中,CIN1未手术组L1(+)和L1(-)的HC2转阴率比较,P=0.022<0.05,有统计学差异.(3)HPVL1壳蛋白对CIN1的转归有较好的预测作用,CIN1患者中L1(+)的HPV转阴率较L1(-)的高.结论(1)CIN1组的L1阳性率大于其他各组,而其他组别的L1阳性率之间均无统计学差异.(2)随访2年结果:未手术组L1(+)和L1(-)的HC2转阴率比较,有统计学差异(P<0.05).(3)HPVL1壳蛋白可作为CIN1的临床预后指标.
简介:背景与目的:细胞黏附分子L1(celladhesionmoleculeL1,L1CAM)是一种跨膜黏附蛋白,在神经系统发育及肿瘤发生中发挥重要作用。本研究运用RNA干扰(RNAinterference,RNAi)技术抑制L1CAM表达,并探讨其对胶质瘤U251细胞多药耐药的逆转作用及相关分子机制。方法:将针对L1CAM的小干扰RNA(siLl)和阴性对照siRNAfsiCon)转染人胶质瘤U251细胞。实验分3组:空白对照组(胶质瘤U251细胞)、阴性对照组(转染siCon的胶质瘤U251细胞)、实验组f转染siLl的胶质瘤U251细胞)。蛋白质印迹法(Westernblotting)~U251细胞中L1CAM、MRPl、pAKT及pERK1/2等蛋白表达。细胞增殖实验检测L1CAM对顺铂(cisplatin)和P13K/AKT抑制剂LY294002抑制U251细胞增殖的影响。免疫荧光染色法检测抑制LICAM表达对U251细胞系中AKT磷酸化情况的影响。结果:实验组L1CAM、pAKT.pERKl/2蛋白表达量明显低于阴性对照组和空白对照组(P〈0.01),但实验组多药耐药蛋白MRPl表达量以及Bcl-2cdBax与阴性对照组和空白对照组相比无明显变化。实验组顺铂和LY294002对U251细胞增殖的抑制率高于阴性对照组和空白对照组,提示抑制LICAM表达后细胞对顺铂和LY294002的敏感性增加。免疫荧光结果显示,与阴性对照组和空白对照组相比,实验组细胞内AKT磷酸化信号明显降低。结论:RNAi抑制L1CAM表达能增强顺铂和LY294002对U251细胞增殖的抑制作用,并可抑制P13K/AKT和MAPK信号激活.一定程度上可逆转胶质瘤细胞的多药耐药性。