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目的:建立一种定量、简单、快速、敏感的微小RNA(miRNA,miR)检测方法,并用其观察一些病理状态下有关miRNA的变化.方法:通过特殊设计的茎环结构的反转录引物,对miRNA进行反转录,然后用相应miRNA的正反向引物对该miRNA进行定量检测,观察重复性和特异性.用此法检测了人巨细胞病毒(HCMV)对滋养细胞(HPT-8)细胞内miR-513表达水平的影响,也检测了结直肠癌组织miR-145水平.结果:用该法扩增miRNA特异性强,结果重复性好,该法检测到HCMV感染对miR-513表达的梯度效应.也发现癌组织和正常组织间miR-145的表达有明显的差异.结论:用荧光定量PCR可以对微小RNA快速有效的检测,在临床工作中可得到很好的应用. 相似文献
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测定了5种56个批次的中药注射剂的二维荧光光谱,提出了激发光谱的第二特征峰的概念,首次以激发波长、发射波长和激发光谱的第二特征峰波长作为基,建立了三维聚类图分析法。结果表明：激发光谱的第二特征峰波长具有较好的特征性;三维聚类图有较好的分类和预测作用,并有较强的可视性。该法可用于中药注射剂的鉴别和聚类分析。 相似文献
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设计并合成了一种新型罗丹明B衍生物荧光分子探针RBA,研究了其光谱性能及对Fe^3＋的识别作用。结果表明：RBA在三羟甲基氨基甲烷—盐酸缓冲溶液和乙醇/水溶液形成的混合介质中,对Fe^3＋有高选择性、高灵敏性的荧光检测。在pH为7.0,553/576 nm条件下,随着Fe^3＋的浓度递增,RBA荧光强度呈现显著线性增强。其荧光增强主要是由于Fe^3＋诱导了分子中的酰胺闭环结构发生开环,导致分子结构的共轭程度增大。此外,RBA对其他常见金属离子Cu2＋,Ag＋,Zn2＋,Cd2＋,Hg^2＋,Na^＋,K＋,Mg^2＋,Ba^2＋,Mn^2＋,Co^2＋,Ni^2＋和Pb2＋等的硝酸盐溶液几乎不引起紫外-可见光谱和荧光光谱变化。 相似文献
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The binding of pefloxacin mesylate （PFLX） to bovine lactoferrin （BLf） and human serum albumin （HSA） in dilute aqueous solution was studied using fluorescence spectra and absorbance spectra. The binding constant K and the binding sites n were obtained by fluorescence quenching method. The binding distance r and energy-transfer efficiency E between pefloxacin mesylate and bovine lactoferrin as well as human serum albumin were also obtained according to the mechanism of Forster-type dipole-dipole nonradiative energy-transfer. The effects of pefloxacin mesylate on the conformations of bovine lactoferrin and human serum albumin were also analyzed using synchronous fluorescence spectroscopy. 相似文献
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对钝顶螺旋藻藻胆体在解离过程中77K荧光发射光谱与光能传递途径进行了研究.在77K荧光发射光谱中,完整藻胆体只有一个峰,位于682nm,这是藻胆体核心-类囊体膜连接多肽的荧光峰;随着藻胆体逐渐解离,首先在649nm出现一个小峰,之后,在661nm又出现一个荧光发射肩,前者是C-藻蓝蛋白的荧光,后者是别藻蓝蛋白的荧光;随着藻胆体解离程度的加重,C-藻蓝蛋白的荧光逐渐加强并成为主峰,别藻蓝蛋白的荧光也逐渐加强,但随后又逐渐减弱,直至消失;682nm主峰逐渐减弱并消失,但在679nm却出现另一个荧光峰,这是别藻蓝蛋白-B的荧光;当别藻蓝蛋白的荧光消失后,679nm荧光峰减弱为荧光发射肩,但仍然有很强的荧光.这表明:C-藻蓝蛋白不但与别藻蓝蛋白相连接,而且还与别藻蓝蛋白-B相连,在钝顶螺旋藻藻胆体中,光能是沿着两条途径传递给光系统Ⅱ的. 相似文献
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对钝项螺旋藻完整藻胆体与解离藻胆体吸收光谱进行了比较研究.随着藻胆体的逐渐解离,其吸收光谱表现出如下变化特点:在紫外光区,吸收峰始终位于355nm,尖形峰逐渐变成钝形峰;在红光区,都有很强的吸收,吸收峰呈平顶状,其半带宽逐渐变小;紫外光区与红光区相对吸收强度的比值逐渐变小;四级导数吸收光谱的小峰数目越来越少.室温荧光发射光谱表明,藻胆体在低于0.9mol/L的磷酸缓冲液中变得不稳定,并开始逐渐解离,解离的藻胆体与完整的藻胆体相比,其荧光发射峰波长逐渐变短. 相似文献
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TIRF microscopy has provided a means to view mobile granules within 100 nm in size in two dimensions. However quantitative analysis of the position and motion of those granules requires an appropriate tracking method. In this paper, we present a new tracking algorithm combined with the unique features of TIRF. Firstly a fluorescence correction procedure was processed to solve the problem of fluorescence bleaching over time. Mobile granules were then segmented from a time-lapse image stack by an adaptive background subtraction method. Kalman filter was introduced to estimate and track the granules that allowed reducing searching range and hence greater reliability in tracking process. After the tracked granules were located in x-y plane, the z-position was indirectly inferred from the changes in their intensities. In the experiments the algorithm was applied in tracking GLUT4 vesicles in living adipose cells. The results indicate that the algorithm has achieved robust estimation and tracking of the vesicles in three dimensions. 相似文献
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INTRODUCTION Adulteration of fresh milk by adding reconsti- tuted milk or the selling of reconstituted milk as the fresh product can be economically advantageous when either a surplus of milk powder exists or in countries where the importation of dried milk powder is subsidized. Adulteration malpractice creates unfair competition, could lead to market distortions, which in turn may impact the local or even the international economy. When legislation prohibits such practice, the detection o… 相似文献