共查询到20条相似文献，搜索用时 679 毫秒
1.
基于反射型激光诱导荧光检测技术,对激光诱导荧光光纤束传感器检测系统的光路进行了设计与分析,重点探讨了光纤探头中光线轨迹问题.该检测系统利用多模光纤束传感器将激光垂直照射到待测样品上,再把样品发出的荧光信号采集到光电倍增管,将光信号转换为电信号,再通过光子计数器和A/D转换后供计算机实时采样.以荧光素钠为试剂,作为检测物质对该检测系统的灵敏度进行评价,在检测池尺寸为35 mm×15 mm时,最小检出限达到3×10-12mol/L,同时得到检测物质的荧光信号强度与溶液浓度成线性关系.由此认为这是一种性能比较优越的检测系统,有利于提高抗干扰能力和检测灵敏度. 相似文献
2.
【目的】通过研究荧光素二叔丁基二甲基硅醚(FTBS)的聚集诱导发光效应,将FTBS用于活细胞的长期荧光示踪。【方法】采用荧光素与叔丁基二甲基氯硅烷发生亲核取代,合成荧光素二叔丁基二甲基硅醚;通过测试其荧光发射强度和粒子直径,首次证实其具有聚集诱导发光效应;通过对人宫颈癌细胞株HeLa的染色试验,确定细胞染色时间和浓度。【结果】通过细胞染色,证实FTBS是具有良好细胞通透性的荧光探针,实现基于FTBS的活细胞长期荧光示踪。【结论】基于FTBS的聚集诱导发光效应和良好的细胞通透性,可将其用于对癌细胞及分裂产生的子细胞进行长时间跟踪监测,对于标记癌细胞和监测癌细胞增殖具有一定意义。 相似文献
3.
为了探索flhA基因在荧光假单胞菌7-14(Pf7-14)鞭毛合成的作用,以铜绿假单胞菌UCBPP-PA14的鞭毛蛋白FlhA(NC_008463.1)为诱饵,在荧光假单胞菌Pf-5(NC_004129)、Pf0-1(NC_007492)和SBW25(NC_012660)的伞基因组中进行BLASTP比对分析,结果在Pf-5、Pf0-1和SBW25的全基因组搜索到flhA的同系物,分别命名为flhAPf-5、flhAPf0-1,和flhASBW25.根据三者的核酸序列,设计简并引物flhA-F/flhA-R,以荧光假单胞菌7-14(Pf7-14)基凶组DNA为模板进行PCR扩增,并对得到的片段测序比对,发现该片段2 130 bp为一完整的开放阅读框,命名为flhAPf7-14.flhAPf7-14在氨基酸水平上与flhAPf-5和flhAPf0-1的同源性分别达到93%和94%.Southern杂交证明flhA 在Pf7-14基因组中为单一拷贝.通过同源重组单交换的方式构建了Pf7-14flhA基因插入失活突变株,结果表明flhA突变体缺失了鞭毛装置并丧失了游动性,而互补菌株则恢复了鞭毛合成能力和游动能力.本研究为今后进一步研究Pf7-14鞭毛合成、菌体游动性与该菌定殖能力及生防能力的关系奠定基础. 相似文献
4.
本文合成了荧光探针香草醛缩苯胺,该探针的荧光可被羟基自由基(·OH)猝灭,藕合Fenton反应,建立了一种荧光猝灭法测定羟基自由基的新方法.该方法的检测线性范围为2.00 ×10-6 -2.00 ×10-5 mol·L-1·检出限为8.00×10-7mol·L-1.利用该方法测定了几种大豆提取液对羟基自由基清除作用,结果满意. 相似文献
5.
朱昌青 《安徽农业大学学报》2000,27(3):294-297
在四磺基锰酞菁存在下 ,高香草酸与过氧化氢作用可形成强荧光二聚体 ,由此建立的测定水溶液中过氧化氢的荧光方法可用于本地区雨水样品的分析。测定所用的荧光试剂不含辣根过氧化物酶 ,从而避免了生物酶在使用过程中因可能的失活给分析工作所带来的困难。方法的检测限为 7.1× 1 0 - 8mol/L,对 1 .0× 1 0 - 6mol/L H2 O2 作 6次平行测量 ,标准偏差为 3 .1 %。 相似文献
6.
【目的】为建立除草剂丁草胺的荧光偏振免疫检测方法,对关键试剂示踪物进行合成与鉴定。【方法】以异硫氰酸荧光素、乙二胺和己二胺为原料,合成了异硫氰酸荧光素乙二胺（EDF）和异硫氰酸荧光素己二胺（HDF）两种中间体,薄层层析法分离出目标产物,电喷雾电离质谱法鉴定;然后将5-氨基荧光素（AF）、EDF、HDF分别与丁草胺半抗原（BMPA）连接,得到3种不同间隔臂的示踪物（BMPA-AF,BMPA-EDF和BMPA-HDF）,利用抗血清稀释曲线测定抗血清效价,竞争抑制曲线测定不同示踪物检测灵敏度。【结果】3种示踪物合成成功,抗血清稀释曲线和竞争抑制曲线显示3种示踪物的抗血清效价分别为1/600、1/1500和1/600,半抑制浓度分别为1 292、433和298 ng•ml-1。【结论】合成出3种不同间隔臂的丁草胺示踪物,对示踪物的性质进行初步研究,为下一步建立丁草胺荧光偏振免疫分析方法奠定了基础。 相似文献
7.
研究了不同质量浓度蛋白质与同质量浓度叶酸相互作用的荧光光谱和产生的荧光强度变化.结果表明,随蛋白质质量浓度的增加产生的荧光强度也逐渐增加,且蛋白质质量浓度与荧光强度之间具有良好的线性关系.还研究了三聚氰氨对蛋白质质量浓度测量的影响,以及用此方法测奶粉中蛋白质含量的可行性.据此建立了有效测量蛋白质质量浓度的以荧光光谱为基础的新方法.该法最低检测限为5×10-6 mg·L-1,检测范围广,线性范围是3.77×10-2~827 mg·L-1(827 mg·L-1不是最大范围,最大值未测定),相关系数为0.998 9,加标回收率为93.71%~106.2%. 相似文献
8.
在荧光及荧光动力学分析中 ,腙类试剂已得到应用[1～ 7] 。腙类试剂荧光法测定Ａｌ3+,Ｇａ3+,Ｚｎ2 +,Ｓｃ3+等已显示出灵敏度高及选择性好的优点。现在虽有腙类试剂荧光法测定锰的报道 ,但是未见水杨醛 - 2 ,4-二氯苯氧乙酰腙在荧光分析中的应用。笔者合成了 1种新萤光剂水杨醛 - 2 ,4-二氯苯氧乙酰腙 ,并观察了其与锰荧光反应的最佳条件。1 材料与方法1 .1 主要仪器和试剂960型荧光光度计 ;72 2型分光光度计 ;醋酸铵缓冲溶液 ;锰标准溶液 ;2 ,4-二氯苯氧乙酸 ;无水乙醇。1 .2 锰标准溶液的配制准确称取 0 .1 872ｇ(± 0 .0 0 0 1ｇ)Ｍ… 相似文献
9.
甲醛(Formaldehyde)又名蚁醛,是一种对身体有害的物质,甲醛在食品中的作用通常是保鲜、增白的水发食品。实验以甲醛与乙酰丙酮在乙酸铵缓冲溶液下反应生成3,5-二乙酰基-1,4-二氢-2,6-二甲基吡啶,该产物的相对荧光强度在一定范围内与甲醛浓度成正比,据此建立了测定甲醛的荧光分析方法,在Ex=350 nm,Em=510 nm测得甲醛标准溶液在不同浓度梯度下的荧光强度,由此绘制出标准曲线,实验检测表明,甲醛含量在0～4.0μg·mL~(-1)时,有良好的线性关系,相关系数r=0.9910,回归方程:y=39.753C+10.676。采用该方法对干鱿鱼丝、鲜鱿鱼、腐竹进行甲醛含量的测定,测得其回收率在96.7%～104.5%之间。 相似文献
10.
11.
Highly extensible Escherichia coli DNA molecules in planar extensional flow were visualized in dilute solution by fluorescence microscopy. For a narrow range of flow strengths, the molecules were found in either a coiled or highly extended conformation, depending on the deformation history of the polymer. This conformation hysteresis persists for many polymer relaxation times and is due to conformation-dependent hydrodynamic forces. Polymer conformational free-energy landscapes were calculated from computer simulations and show two free-energy minima for flow strengths near the coil-stretch transition. Hysteresis cycles may directly influence bulk-solution stresses and the development of stress-strain relations for dilute polymer flows. 相似文献
12.
The conformational dynamics of individual, flexible polymers in steady shear flow were directly observed by the use of video fluorescence microscopy. The probability distribution for the molecular extension was determined as a function of shear rate, gamma;, for two different polymer relaxation times, tau. In contrast to the behavior in pure elongational flow, the average polymer extension in shear flow does not display a sharp coil-stretch transition. Large, aperiodic temporal fluctuations were observed, consistent with end-over-end tumbling of the molecule. The rate of these fluctuations (relative to the relaxation rate) increased as the Weissenberg number, gamma;tau, was increased. 相似文献
13.
Dynamic instability-the switching of a two-state polymer between phases of steady elongation and rapid shortening-is essential to the cellular function of eukaryotic microtubules, especially during chromosome segregation. Since the discovery of dynamic instability 20 years ago, no other biological polymer has been found to exhibit this behavior. Using total internal reflection fluorescence microscopy and fluorescence resonance energy transfer, we observe that the prokaryotic actin homolog ParM, whose assembly is required for the segregation of large, low-copy number plasmids, displays both dynamic instability and symmetrical, bidirectional polymerization. The dynamic instability of ParM is regulated by adenosine triphosphate (ATP) hydrolysis, and filaments are stabilized by a cap of ATP-bound monomers. ParM is not related to tubulin, so its dynamic instability must have arisen by convergent evolution driven by a set of common constraints on polymer-based segregation of DNA. 相似文献
14.
Morawetz H 《Science (New York, N.Y.)》1988,240(4849):172-176
Nonradiative energy transfer between fluorescent labels attached to polymers has been used to characterize polymer miscibility, the interpenetration of chain molecules in solution, micelle formation in graft copolymers, the unfolding of collapsed chain molecules in polymer melts, and the transfer of energy absorbed by a large number of donor labels to a small number of acceptors by an "antenna effect." The change in the emission spectrum after ionomer solutions with different fluorescent counterions were mixed provided rate constants for counterion interchange. The fluorescence behavior of dispersions of donor-labeled polymers stabilized by a graft copolymer with acceptor fluorophores in the solution phase led to inferences about the morphology of the dispersed particles. 相似文献
15.
研究了以PVC膜为支持体系，以四(4-溴)苯基铂卟啉为敏感物质的荧光猝灭氧传感器对分子氧的响应特性．该氧传感器敏感膜的最大激发波长为402nm，最大发射波长为664nm，分子氧可以有效地猝灭四(4-溴)苯基铂卟啉敏感膜的荧光．在100％N2和100％O2中的荧光强度之比大于40倍；在N2饱和和空气饱和的水中荧光强度之比大于14倍，有较高的灵敏度，其寿命大于3个月。 相似文献
16.
Individual polymers at thermal equilibrium were exposed to an elongational flow producing a high strain rate, and their dynamics were recorded with video fluorescence microscopy. The flow was turned on suddenly so that the entire evolution of molecular conformation could be observed without initial perturbations. The rate of stretching of individual molecules is highly variable and depends on the molecular conformation that develops during stretching. This variability is due to a dependence of the dynamics on the initial, random equilibrium conformation of the polymer coil. The increasing appearance at high strain rates of slowly unraveling hairpin folds is an example of nonergodic dynamics, which can occur when a statistical mechanical system is subjected to nonadiabatic, or "sudden," external forces. 相似文献
17.
为了研究纳米银对染料光学性质的影响,通过共混法制备得到RodamineB/PMMA/Ag复合材料,采用紫外-可见吸收光谱和透射电镜等测试方法对其结构进行分析,结果说明通过控制纳米银的结构与制备条件,可以获得均匀分散的纳米银掺杂聚合物的复合材料;进一步采用荧光与m线法测试,对其发光学性质与平面波导性质进行表征,结果表明,通过掺杂纳米银能有效地增强固体薄膜中染料荧光强度,并可望被应用于平面光波导材料中。 相似文献
18.
纳米铜/聚苯乙烯-丁二烯(SBS)杂化材料研究 总被引：1，自引：0，他引：1
采用脉冲激光轰击法连续制备了纳米铜,进而采用共混法连续制备了纳米铜/SBS杂化材料,用UV-V is、TEM、荧光光谱、FT-IR和TG-DTA对其结构和性质进行了表征.结果表明因为金属铜纳米颗粒的引入表面原子配位不足,表面能极高,活性高,很容易与SBS链段中的不饱和键相互作用,导致UV-V is吸收峰的移动和消失,SBS分子的荧光部分淬灭,整体荧光强度下降,与C=C双键相连的C-H红外变形振动吸收频率的降低;TEM观察显示由于聚合物链段的空间位阻及聚合物链段与铜纳米颗粒的相互作用对铜纳米颗粒的团聚产生阻碍,使杂化材料中铜纳米颗粒的尺寸受到限制,故铜纳米颗粒在SBS在中有较高的稳定性.TG-DTA结果发现Cu/SBS杂化材料的分解温度比SBS高,高温失重较小,热稳定性较好,这是由于Cu纳米粒子和SBS中的C=C双键之间的相互作用,形成具有桥键的结构,使聚合物SBS大分子间的作用力增大所致. 相似文献
19.
A novel chemical sensor has been developed in which the polymer ethylene-vinyl acetate is used as a controlled-release system to deliver reagents to the sensing region of an optical fiber for a homogeneous competitive immunoassay based on fluorescence energy transfer. A competition reaction is used to enable continuous measurements of the solution antigen concentration. More generally, the technique allows irreversible indicating chemistries to be used in the construction of chemical sensors that can measure continuously for long periods. Although the sensor configuration has not been optimized in all respects, data are presented for a model system in which a fluorescein-labeled antibody and Texas Red-labeled immunoglobulin G (IgG) are used. 相似文献
20.
岩石表面的润湿性影响聚合物微观和宏观驱油效率。采用可视化微观模型和微观照相技术研究了强水湿和油湿多孔介质下聚合物微观驱油效率和驱替机理。分析了束缚水与稠油分别在两种润湿介质下的微观形态和分布对聚合物的吸附、滞留,连续性和非连续性流动,驱替前缘以及洗油效率的影响。微观模型实验结果表明,在水湿环境,地层水趋向分布于岩石骨架表面并在孔壁附近形成较厚的水膜,聚合物趋于附着在孔壁处,在这些区域聚合物的洗油效率较高;在油湿环境,束缚水主要以非连续相分布在孔隙介质中,聚合物溶液发生咬断效应,原油吸附在孔喉处,聚合物只能部分扫除原油,乳液的形成能辅助聚合物溶液驱替油相。聚合物在水湿介质的微观驱油效率明显高于油湿介质。岩心流动实验结果与微观模型分析一致,相同浓度的聚合物溶液在强水湿岩心前缘突破所需的时间长于油湿岩心,突破前缘更规整,水湿岩心和油湿岩心的水驱采出程度分别为21.5%OOIP和15%OOIP。聚合物在油湿岩心的“门槛”黏度较大。聚合物黏度为500 mPa·s时,水驱后水湿岩心和油湿岩心的原油采收率增幅分别为23%OOIP和17%OOIP。 相似文献