聚酯聚醚嵌段共聚物与1,4-二咔唑环丁烷在激发态及基态的相互作用

<正> 聚酯聚醚嵌段共聚物具有十分良好的物理和机械性能,能加工成橡胶、纤维、塑料胶粘剂等,近年来也有作为医用高分子材料的报道。所以对聚酯聚醚嵌段共聚物的研究十分活跃。然而,有关其光物理性质的研究还很少见。本文报道了混合聚醚-聚酯嵌段共聚物(MPEE)与反式1,4-二咔唑环丁烷(1,4-DCC)在激发态和基态下的相互络合作用。结果表明,MPEE可以猝灭1,4-DCC的荧光,同时形成激基复合物。在分散     

Single-molecule fluorescence detection in microfluidic channels—the Holy Grail in μTAS?

Both single-molecule detection (SMD) methods and miniaturization technologies have developed very rapidly over the last ten years. By merging these two techniques, it may be possible to achieve the optimal requirements for the analysis and manipulation of samples on a single molecule scale. While miniaturized structures and channels provide the interface required to handle small particles and molecules, SMD permits the discovery, localization, counting and identification of compounds. Widespread applications, across various bioscience/analytical science fields, such as DNA-analysis, cytometry and drug screening, are envisaged. In this review, the unique benefits of single fluorescent molecule detection in microfluidic channels are presented. Recent and possible future applications are discussed.Dedicated to the memory of Wilhelm Fresenius     

Oligonucleotides containing new fluorescent 1-phenylethynylpyrene and 9,10-bis(phenylethynyl)anthracene uridine-2′-carbamates: synthesis and properties

The synthesis of two novel fluorescent uridine-2′-carbamate phosphoramidites is described. The reagents carrying fluorescent polyaromatic hydrocarbons 1-phenylethynylpyrene (PEPy) or 9,10-bis(phenylethynyl)anthracene (BPEA) are suitable for oligonucleotide synthesis. Prepared oligonucleotide conjugates show strong dye emissions at 401 and 485 nm, but low FRET rate when located in the oligonucleotide duplex. The dyes show considerable compensation of the usual carbamate duplex destabilization. The possible explanation of both effects is binding of PEPy and BPEA to the minor groove of the DNA duplex.     

Lifetimes and Quenching of the Ā 2A′(υ3′ = 0 – 2) → X̄ 2A″ Fluorescence of HSO

Fluorescence lifetimes of vibrational levels of the first electronically excited state (ā ² A′) of HSO, determined by the technique of discharge flow and laser-induced fluorescence, are 81 ± 10, 74 ± 8, and 76 ± 14 μs for υ₃′ = 0, 1 and 2, respectively. The rate coefficients of quenching of each level by He, N₂, O₂ and O₃ were measured; the coefficients for HSO (ā, υ₃′ = 0 – 2) quenched by O₃ arc 35–50 times as great as those of HSO by He.     

氟代二苯乙烯氨基酸的合成及性能

以4-碘-L-苯丙氨酸为初始原料,经羧基和氨基的保护得到化合物2;化合物2与4-氟苯乙烯进行Heck反应得化合物3;化合物3脱去保护基得氟代二苯乙烯氨基酸(4,47.4%);其结构经1H NMR,13C NMR,IR和MS(ESI-TOF)确证。光学性质研究结果表明:4的激发、发射波长分别为314 nm和355 nm,斯托克斯位移为41 nm,荧光量子产率为0.22。化合物4在甲醇溶液中存在光致顺反异构现象,反式→顺式结构转变速率常数为0.026 min^-1。     

The adsorption of endothelin 1 to phospholipids is governed by electrostatic interactions: A monolayer and fluorescence study

In order to elucidate the influence on the lipidic environment on the recognition process of its membrane associated receptor, the interactions of the vasoconstrictor peptide endothelin 1 with various phospholipids have been investigated using different lipidic model membranes: monolayers at constant surface pressure, vesicles and micelles. A monolayer study of ET1 adsorbed onto the water surface has shown that the C-terminus of the peptide points towards the aqueous phase. Penetration measurements into lipidic monolayers indicate that ET1 adsorbs to phospholipids with an orientation similar to that of the air–water interface and fluorescence measurements are in agreement with such an orientation of the peptide. This adsorption is selective for neutral phospholipids and indicates that the nature of the phospholipid headgroups is of major importance for the approach of the membrane associated receptor.     

Synthesis and properties of coumarin-derived organogelators

A new family of coumarin derivatives containing amide group with different alkyl chain lengths was synthesized and their properties as organogelators were evaluated. It was found that the organogelation abilities were not obviously affected by the alkyl spacer length of amide group. Helical morphologies formed either in nonpolar or high polar solvents by most of the gelators. Occurrence of reversible and stereoselective photodimerization of the gel formed by 4-(7′-coumarinoxy)-N-octadecylbutanamide (3a) in cyclohexane was confirmed by ¹H NMR, UV absorption, and fluorescence spectra. The photoreaction of the gel proceeded without any dissolution, but the drastic microscopic changes of gel morphologies accompanied with the irradiation were identified using SEM and AFM investigations.     

双嘧达莫的荧光光谱分析法

以荧光光谱法研究了双嘧达莫在溴化十六烷基三甲基铵(CTMAB)、β_环糊精 (β_CD)、十二烷基硫酸钠 (SDS)等介质体系中的荧光性质 ,发现CTMAB、SDS和 β_CD对双嘧达莫均有不同程度的荧光增敏作用 ,提出了在CTMAB、SDS和 β_CD水溶液中测定双嘧达莫的荧光光谱分析法 ;该法灵敏度高 ,检出限低(3.20×10 -9mol/L) ,在6.40×10 -8～3.20×10 -6mol/L范围内荧光强度与双嘧达莫的浓度呈良好线性关系     

A novel selective fluorescent chemosensor for Cu（Ⅱ）

A novel fluorescence enhancement Cu~(2 ) chemosensor derived from coumarin was prepared.Emission study found that it exhibits evident Cu~(2 )-amplified fluorescence prior to Co~(2 ),Pb~(2 ),Mg~(2 ),Mn~(2 ),Ni~(2 ),Zn~(2 ),Fe~(3 ),Ag~ and Cd~(2 ),and the largest emission enhancement factor is about 9 at a ratio of 2:1 (chemosensor 1/Cu~(2 )).     

Synthesis of a Photolabeling Probe for the Study of Antiviral Mechanism of Ribavirin

Ribavirin has been used in urgency to treat SARS patients recently. In order to study its antiviral mechanism by photolabeling approach, we have synthesized and characterized 5-azido-1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxiamide 1 as a photolabeling probe of ribavirin. The azidotriazole nucleoside showed rapid and clean photochemical reaction, suggesting that 1 is a promising probe to study the antiviral mechanism ofribarivin by photolabeling.