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1.
Pyoverdine A(PvdA)是荧光假单胞菌分泌的一种水溶性较高的黄绿色荧光铁载体。在50 mmol·L-1Tris-HCl,pH 8.0条件下,使用紫外-可见吸收差光谱、荧光光谱研究了铽(Ⅲ)与荧光铁载体PvdA的结合。结果表明铽(Ⅲ)可与PvdA结合形成1:1的配合物,条件结合常数为(4.44±0.82)×1014mol-1·L。在生理条件下,PvdA可竞争伴清蛋白N-,C-端结合的铽(Ⅲ)形成Tb-PvdA配合物;Tb-PvdA与荧光假单胞菌细胞表面受体FpvA结合形成Tb-PvdA-FpvA复合物。  相似文献   

2.
本文通过分子生物学方法将八肋游仆虫中心蛋白N端半分子loop区的首个氨基酸,天冬氨酸Asp37和Asp73,分别突变为带相反电荷的赖氨酸。使用铽敏化荧光、TNS疏水探针研究了八肋游仆虫中心蛋白N端半分子loop区的首个氨基酸的作用。结果表明:当中心蛋白loop Ⅰ区37位的天冬氨酸突变为赖氨酸后,loop Ⅰ丧失了金属离子结合能力,进而影响了中心蛋白依赖于金属离子的构象变化;而loop Ⅱ区73位的天冬氨酸突变为赖氨酸后仍保持金属离子结合能力,依赖于金属离子的构象变化减小。中心蛋白发挥大部分生物功能都依赖于金属离子,这就表明loop Ⅰ区37位的天冬氨酸在中心蛋白发挥生物功能时起着重要作用,是不可缺少的。在10 mmol·L-1 Hepes、pH 7.4、20 mmol·L-1 KCl条件下,八肋游仆虫中心蛋白N端半分子loop Ⅱ与金属离子Tb3+和Ca2+的结合常数分别为:K(Tb3+)=(8.31±0.18)×104 L·mol-1K(Ca2+)=(0.94±0.12)×102 L·mol-1,中心蛋白N端半分子的两个金属结合部位结合能力顺序为:Ⅰ>Ⅱ。  相似文献   

3.
采用具有白磷钙矿结构的磷酸盐作为目标产物,通过高温固相法制备了发光颜色可调的 Ca8MgBi(PO4)7∶Ce3+,Tb3+荧光粉。利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和荧光光谱等表征手段对其物相组成、微观形貌及发光性能进行了详细研究。结果表明:掺杂少量的 Ce3+、Tb3+并没有改变 Ca8MgBi(PO4)7基质的晶体结构。荧光光谱和荧光寿命曲线确定了 Ce3+-Tb3+之间存在能量传递,其能量传递机制为四极-四极相互作用,能量传递效率可达 81%。固定 Ce3+浓度而逐渐增加 Tb3+的掺杂量时,系列Ca8MgBi(PO4)7∶0.08Ce3+,yTb3+荧光粉的发光颜色可由蓝光调至绿光,从而实现发光颜色的可控化。  相似文献   

4.
利用微乳液方法,合成了铈、铽共掺杂的氟镁钾纳米粒子,研究了体系中Ce3+→Tb3+的发光特性以及它们之间的相互作用,结果表明KMgF3∶Ce3+,Tb3+纳米粒子中存在Ce3+→Tb3+的能量传递过程,即Ce3+可以将吸收的能量直接传递给Tb3+离子,使得Tb3+的绿色发光强度大为增加。  相似文献   

5.
长余辉发光材料的研究与应用,已有近100年的历史,目前仍在许多领域中有着重要应用。此类材料与其他光致发光材料具有相同的发光性能.只是更注重其发光的衰减过程和热释光性能。如.ZnS:Cu作为黄绿色的长余辉发光材料,在1992年以前是余辉性能最好的长余辉发光材料,一直处于发光研究工作的中心。  相似文献   

6.
Si5P6O25∶Tb3+的结构与荧光性质   总被引:3,自引:0,他引:3       下载免费PDF全文
Tb3+ ions were incorporated in P-Si matrix material through a sol-gel process. Luminescence properties of Tb3+ as a function of dopant, firing temperature, composition and structure of matrices were investigated. The gels synthesized by the reaction of P2O5 or H3PO4 with tetraethoxy silane and TbCl3 as dopant were fired in air from the temperature 25~1000℃ to form P-Si crystalline phase. The crystal structure was determined by powder X-ray diffraction. Si5O(PO4)6 were the only crystalline phase and belong to hexagonal crystal system. The emission of 5D4-7F5(~545nm) transition of Tb3+ in the P-Si system is composed of two peaks. The amount of doping Tb3+ varied from 0.664% to 1.644%, and no obvious concentration quenching was observed in this doping concentra-tion range. The intensity of Tb3+ emission increased with firing temperature increasing and becomes stable at 800~1000℃.  相似文献   

7.
Mg2+与胆汁蛋白质相互作用研究   总被引:2,自引:0,他引:2  
胆汁是一中性溶液,在胆汁固形物中,胆汁酸盐、胆固醇、磷脂、蛋白质、胆红素分别占总质量的65%、3%、20%、5%及1%。蛋白质是胆汁固形物中第四多成分,在胆汁的生理功能的发挥和胆结石的形成中起到重要的作用。研究表明,胆汁蛋白质的主要成分是糖蛋白,主要由胆囊粘膜上皮细胞产生  相似文献   

8.
BaLiF3:Ce 3+纳米粒子的制备及其光谱特性   总被引:7,自引:0,他引:7  
BaLiF3属立方钙钛矿型复合氟化物, 作为高效闪烁晶体可用于热中子检测[1]. 由于其能带隙宽, 易于实现各种不同价态稀土离子掺杂, 可以获得许多可调谐性质, 因此它也是比较理想的光学功能材料的基质[2]. Ce3+激活的BaLiF3晶体作为紫外发射的短波固体激光材料和光放大材料的研究多有报道[3~5]  相似文献   

9.
采用芳香族π共轭及含氮原子有机连接剂,合成同构铽、铕发光配位聚合物(CPs){[Eu(PLIA)1.5(H2O)2]·H2O}n (1)和{[Tb(PLIA)1.5(H2O)2]·H2O}n (2),其中H2PLIA=5-((吡啶-4-基甲基)氧基)苯-1,3-二甲酸。对合成的配合物进行了结构测定、表征和荧光痕量识别实验研究。2个同构配合物具有理想的三维框架结构,ππ堆积及氢键等弱相互作用增强了其化学稳定性;表征显示配位聚合物12具有良好的荧光性质、结晶性、热力学稳定性及结构完整性,可作为荧光传感的材料。12对水溶液中的Zr4+、Cr2O72-和Fe3+、HPO42-具有选择性好、灵敏度高的荧光识别能力,其检出限分别为0.139 μmol·L-1(1,Zr4+)、0.626 μmol·L-1(1,Cr2O72-)、0.430 μmol·L-1(2,Fe3+)、1.36 μmol·L-1(2,HPO42-)。探究了12作为探针的荧光猝灭机理。更有趣的是,12具有指纹识别性能,其荧光指纹纹路清晰连贯,细节明显,可被清晰观察。  相似文献   

10.
采用优化的高温固相方法制备了稀土离子Eu3+和Tb3+掺杂的La7O6(BO3)(PO42系荧光材料,并对其物相行为、晶体结构、光致发光性能和热稳定性进行了详细研究。结果表明,La7O6(BO3)(PO42:Eu3+材料在紫外光激发下能够发射出红光,发射光谱中最强发射峰位于616 nm处,为5D07F2特征能级跃迁,Eu3+的最优掺杂浓度为0.08,对应的CIE坐标为(0.610 2,0.382 3);La7O6(BO3)(PO42:Tb3+材料在紫外光激发下能够发射出绿光,发射光谱中最强发射峰位于544 nm处,对应Tb3+5D47F5能级跃迁,Tb3+离子的最优掺杂浓度为0.15,对应的CIE坐标为(0.317 7,0.535 2)。此外,对2种材料的变温光谱分析发现Eu3+和Tb3+掺杂的La7O6(BO3)(PO42荧光材料均具有良好的热稳定性。  相似文献   

11.
Glu is highly conserved as the first amino acid of E-helix of the EF-hand protein. In this paper, Glu 101, the first amino acid of E-helix of the third EF-hand motif in Euplotes octocarinatus centrin (EoCen) was mutated to be Lys by the method of site direct mutation. Tb3+ and TNS were used as fluorescence probes in the study of the effect of this mutation to the metal binding characteristic of EoCen by fluorescence spectra. Results indicate that compared with EoCen, the mutation protein (E101K) displays a different Tb3+ binding characteristic and an increased hydrophobic exposure surface. Polyacrylamide gels electrophoresis indicated that the electrophoretic mobilities of EoCen and E101K are distinctly different. It can be deduced that the conformation of EoCen has been altered by this mutation. The general conditional binding constant of Tb3+ to the three loops of EF-hand sites I-III in E101K was calculated to be (5.64+/-0.57)x10(5)M(-1) according to the modified equation of the single binding process.  相似文献   

12.
Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln3+). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb3+–FQ and Eu3+–FQ complexes have been investigated in this contribution. Ce4+–SO32− in acidic conditions was taken as the CL system and sensitized CL intensities of Tb3+–FQ and Eu3+–FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb3+–FQ complexes show characteristic peaks of Tb3+ at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb3+–ENX, Tb3+–NFLX, Tb3+–LMFX and Tb3+–FLRX display relatively strong emission intensity compared with Tb3+–OFLX, Tb3+–RFX, Tb3+–GFLX and Tb3+–SPFX. Quite weak peaks with unique characters of Eu3+ at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu3+–ENX, but no notable sensitized luminescence and CL of Eu3+ could be observed when Eu3+ is added into other FQ. The distinct differences on emission intensity of Tb3+–FQ and Eu3+–FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln3+. The different sensitized luminescence and CL signals among Tb3+–FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb3+–FQ and Eu3+–FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results.  相似文献   

13.
The spectroscopic properties of interactions involving horseradish peroxidase (HRP) and Tb(3+) in the simulated physiological solution was investigated with some electrochemical and spectroscopic methods, such as cyclic voltammetry (CV), circular dichroism (CD), X-ray photoelectron spectroscopy (XPS) and synchronous fluorescence (SF). It was found that Tb(3+) can coordinate with oxygen atoms in carbonyl groups in the peptide chain of HRP, form the complex of Tb(3+) and HRP (Tb-HRP), and then lead to the conformation change of HRP. The increase in the random coil content of HRP can disturb the microstructure of the heme active center of HRP, in which the planarity of the porphyrin cycle in the heme group is increased and then the exposure extent of the electrochemical active center is decreased. Thus Tb(3+) can inhibit the electrochemical reaction of HRP and its electrocatalytic activity for the reduction of H(2)O(2) at the Au/Cys/GC electrode. The changes in the microstructure of HRP obstructed the electron transfer of Fe(III) in the porphyrin cycle of the heme group, thus HRP catalytic activity is inhibited. The inhibition effect of Tb(3+) on HRP catalytic activity is increased with the increasing of Tb(3+) concentration. This study would provide some references for better understanding the rare earth elements and heavy metals on peroxidase toxicity in living organisms.  相似文献   

14.
用分子生物学方法表达、纯化了游仆虫中心蛋白及N-端半分子,用铽荧光探针法、离子竞争法研究了pH 7.4,0.01 mol· L-1 Hepes条件下中心蛋白与铽、钙的结合性质。结果表明中心蛋白有4个铽结合部位,其中2个为高亲合结合部位、2个为低亲合结合部位。具有2个低亲合结合部位的中心蛋白半分子与铽结合的条件常数是(2.13±0.10)×105 L·mol-1,与钙结合的条件常数是(7.52±0.02)×102 L·mol-1。  相似文献   

15.
通过还原方法制备了Tb3+离子掺杂的硼酸锌玻璃,并观察到在254 nm紫外光激发后有明亮的绿色长余辉发光现象,余辉时间达6 h。通过激发与发射光谱、余辉光谱、余辉衰减曲线、热释光谱、热释光释出速率衰减曲线等得到的信息,研究了Tb3+离子掺杂的硼酸锌玻璃的发光性质。  相似文献   

16.
CeF3 and CeF3:Tb3+ nanocrystals were successfully synthesized through a facile and effective polyol-mediated route with ethylene glycol (EG) as solvent. Various experimental techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) spectra as well as decay dynamics were used to characterize the samples. The results indicated that the content of NH4F and reactant concentrations were key factors in the product shape and size. Excessive NH4F was necessary for the formation of hexagonal nanoplates. The specific morphology of product can be controlled by changing the NH4F content and reactant concentrations. In addition, Tb3+ doped-CeF3 sample shows strong green emission centered at 544 nm corresponding to the 5D4-7F5 transition of Tb3+. Due to the decrease of nonradiative decay rate, the lifetime of 5D4 level of Tb3+ become longer gradually upon increasing the size of product.  相似文献   

17.
采用高温固相法合成了NaBaPOM4:Tb3+绿色荧光粉, 并研究了材料的发光性质. NaBaPOM4:Tb3+材料呈多峰发射, 发射峰位于437、490、543、587和624 nm, 分别对应Tb3+5D37F45D47FJ=6, 5, 4, 3跃迁发射, 主峰为543 nm; 监测543 nm发射峰, 所得激发光谱由4f75d1宽带吸收(200-330 nm)和4f-4f 电子吸收(330-400 nm)组成, 主峰为380 nm. 研究了Tb3+掺杂浓度, 电荷补偿剂Li+、Na+、K+和Cl-, 及敏化剂Ce3+对NaBaPOM4:Tb3+材料发射强度的影响. 结果显示: 调节激活剂浓度、添加电荷补偿剂或敏化剂均可以在很大程度上提高材料的发射强度.  相似文献   

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