TIME-GATED FLUORESCENCE IMAGING FOR THE DIAGNOSIS OF TUMORS IN A MURINE MODEL

A system for time-gated fluorescence imaging was used to perform measurements on tumor-bearing mice treated with hematoporphyrin derivative (HpD). The aim of the study was to define the potential of this technique in the diagnosis of tumors by taking advantage of the long fluorescence lifetime of the exogenous dye with respect to the decay times of the natural fluorescence. After the administration of three different drug doses (5, 10 and 25 mg/kg body weight), fluorescence images were acquired at various uptake times (from 2 h to 10 d), to determine the best instrumental conditions and experimental procedure for the detection of tumors in the murine model considered. The optimal fluorescence contrast between the tumor area and the surrounding healthy tissue was found at 12 h after the administration of either 5 or 10 mg/kg HpD and was anticipated at 8 h for the highest drug dose. In this optimum condition, the tumor region could be identified even after the injection of 5 mg/kg HpD. A better fluorescence contrast was always obtained in 15 ns-delayed images with respect to synchronous ones.     

在阳离子乳化剂的存在下八甲基环四硅氧烷的乳液聚合

研究了八甲基环四硅氧烷(D_4)在十二烷基二甲基苄基卤化铵及碱存在下乳液聚合的反应机理。聚合分二步进行:D_4先开环生成具有端羟基的聚二甲基硅氧烷,然后再缩合。反应终点有二个平衡反应;不同分子量的羟基封头的聚二甲基硅氧烷的平衡,以及羟基封头的线型聚硅氧烷和环硅氧烷的平衡。平衡时羟基封头的聚硅氧烷的量为87％并提出了主要反应位置是在胶束表面并逐渐转移到随后形成的聚合物颗粒表面,单体液滴是次要反应区。     

表面活性剂存在下铽-镥(钆、钇)-乙酰水杨酸共发荧光体系的研究

本文研究了镥等三种稀土离子与铽-乙酰水杨酸配合物产生的共发荧光效应。在最佳条件下,Lu³⁺、Gd³⁺、Y³⁺的存在可使铽-乙酰水杨酸配合物的荧光分别增强108,58和73倍。讨论了共发光体系的形成条件和荧光特性。利用Tb-Lu-乙酰水杨酸体系和Tb-Lu-乙酰水杨酸-乙二胺四乙酸-十六烷基三甲基溴化铵体系分析了合成稀土样品和包头稀土标准氧化物中的铽,结果满意,加标回收率为90.5～105.6%,并对共发光的机理和表面活性剂的作用进行了初步探讨。     

TIME-GATED FLUORESCENCE OF BLEPHARISMIN, THE PHOTORECEPTOR PIGMENT FOR PHOTOMOVEMENT OF Blepharisma

Abstract— A computer-controlled apparatus for time-resolved laser fluorescence spectroscopy has been used to measure fluorescence lifetimes, time-integrated and time-gated spectra of crude extracts of blepharismin, the photoreceptor pigment of the ciliated photoresponsive protozoan Blepharisma japonicum , in ethanol, aqueous solutions and detergent micelles. The effect of hydroxyl concentration has been investigated in both alcohol and water solutions. A short-living (0.2-0.4 ns) molecular species, emitting at 600 nm, is predominant in aqueous solutions at pH < 11.7, whereas in pure ethanol solutions an intermediate-living species (about 1 ns), still fluorescing at 600 nm, prevails. Upon increasing OFF concentration, a third, long-living (about4–6 ns) molecular species, emitting at 660 nm, is formed in all the examined media. This species has been tentatively identified as the negatively charged form of the photoreceptor pigment, whereas the short-living and the intermediate-living fluorescence emissions have been attributed respectively to the phenolic and the quinonic neutral forms of blepharismin. The phenolic form in its ground state is suggested to be the molecular species from which proton release occurs.     

在两性表面活性剂存在下,5-Cl-PADAB分光光度测定铝合金中的镍

用5-Cl-PADAB作为测定钴、钯的灵敏试剂已有报导,作者曾用5-Cl-PADAB在表面活性剂存在下,对Ag⁺的协同增色作用作了研究,并用以测定微量银,获得良好结果。本文研究了在阴、非离子两性表面活性剂AES(烷基聚乙二醇醚硫酸酿)存在下,利用镍与5-Cl-PADAB生成红紫色络合物的吸收光谱,拟定出直接光度测定镍的方法。该体系具有显色速度快,络合物稳定性好,灵敏度较高(ε₅₃₇=8.1×10⁴),操作简便等优点。用NaF-酒石酸钾钠-硫脲作掩蔽剂,该法用于直接测定铝合金中的微量镍,结果颇为满意。     

两性和非离子混合表面活性剂存在下铀-铬天菁S体系分光光度法研究

本文研究了铀-铬天菁S-混合表面活性剂多元络合物的形成条件,初步探讨了两性-非离子混合表面活性剂的协同作用。本文采用CyDTA-酒石酸混合掩蔽剂,直接测定了以高钍、高稀土、高锆为主的矿石中的微量铀,结果令人满意。     

非离子型表面活性剂-苯芴酮分光光度测定痕量钛

用苯芴酮测定钛的方法,资料中已有过报导,但这些方法的灵敏度均偏低。本文在此基础上研究了在盐酸介质中,以非离子型表面活性剂烷基酚聚乙二醇醚(以下简称OP-10)-苯芴酮分光光度测定微量钛的适宜条件,提出了一个手续简便、选择性好、灵敏度高的新方法。络合物的摩尔吸光系数ε=1.78×10⁵、桑德尔灵敏度S=0.00027微克/厘米²,λ最大为532纳米;钛含量在0-3微克/25毫升符合比耳定律。     

ASSOCIATION PHENOMENON OF A MIXED CATIONIC SURFACTANT IN NON-AQUEOUS SYSTEM

Pseudoternary phase diagrams of a mixture of two cationic surfactants, hexan-1-ol and a third component consisting of glycerol, formamide, water/glycerol or water/formamide were obtained. These diagrams were then contrasted with its water counterpart.

The results showed that the association phenomenon were entirely different from that of the corresponding water system. The lamellar liquid crystalline region was absent in both of the glycerol or formamide systems. This indicated a less ordered or destabilizing effect in the association structure resulting in the replacement water with that of glycerol or formamide. The presence of formamide resulted in a more destabilizing effect compared to the glycerol. This was shown by the smaller lamellar liquid crystal region obtained in the pseudoternary phase diagram containing equal weight ratio of water and formamide.     

PROBING THE STRUCTURE OF HPD BY FLUORESCENCE SPECTROSCOPY

Fluorescence emission spectra indicate that oligomers containing both hematoporphyrin and its dehydration products (vinyl porphyrins) comprise the tumor-localizing fraction of HPD. In the relatively polar solvent methanol, the vinyl porphyrins exhibit reduced fluorescence yields while the hematoporphyrin residues are relatively resistant to fluorescence quenching by Fe+3. In the less polar solvent tetrahydrofuran, fluorescence from oligomeric vinyl porphyrins was enhanced, and Fe+3-induced quenching of oligomeric hematoporphyrin promoted. These, together with other studies in biological systems, suggest a substantial degree of interaction among the porphyrin units contained in these oligomers, as a function of the polarity of the environment.     

在非离子表面活性剂存在下邻羧基苯基重氮氨基偶氮苯吸光光度法测定微量银

提出了一种测定微量银的吸光光度分析新方法。于硼砂-氢氧化钠缓冲溶液中(pH 10.5～11.0),在乳化剂OP存在下,Ag(Ⅰ)与邻羧基苯基重氮氨基偶氮苯(OCDAA)形成1:3稳定的红色配合物,其λ_(max)=540nm,对比度△λ=126nm,表观摩尔吸光系数ε_(540)=8.2×10~4。而在pH 10.0～10.6的相同缓冲溶液中,改用Triton X-100,且加入三乙醇胺后,配合物的λ_(max)=546nm,△λ=136nm,ε_(546)=9.9×104。两种显色体系均在Ag(Ⅰ)0～12μg/25ml范围内服从比耳定律。研究了显色反应条件和共存离子的影响。在试液中加入浓硫酸后加热处理和EDTA的掩蔽作用下,方法用于定影液的分析,六次测定的相对标准偏差为2.3％,平均回收率为98.3％。     

BEHAVIOUR OF MICELLES OF A NON-IONIC SURFACTANT IN THE PRESENCE OF CONCENTRATED ELECTROLYTES AT DIFFERENT TEMPERATURES

Micelle formation of nonylphenol polypropylene polyethylene oxide (NPE-1800) was investigated in aqueous and aqueous electrolyte solutions. The study focused on the effect of temperatures, 25, 30, 35 and 40°C and on the effect of concentrated inorganic electrolytes, NaNO₃, KCI, KNO₃, K₂SO₄ and MgCl₂.6H₂O. The Critical Micelle Concentration (CMC) was determined by surface tension measurements. On the basis of the actual CMC and its temperature dependence, the thermodynamic functions of micelle formation (δH°, δS°, δG°) were calculated.

According to the experimental results, the CMC at high electrolyte concentration increases with increasing temperature. This behaviour is attributed to the salting-in mechanism.

Viscometry supports the behaviour of NPE-1800 in concentrated electrolytes and the decrease of (η is attributed to the decrease of the solvency of the electrolytic solution.     

AGE-RELATED CHANGES IN THE FLUORESCENCE OF MELANIN and LIPOFUSCIN GRANULES OF THE RETINAL PIGMENT EPITHELIUM: A TIME-RESOLVED FLUORESCENCE SPECTROSCOPY STUDY

The photophysical properties of purified populations of melanin and lipofuscin granules from human retinal pigment epithelium, and their changes with donor age, have been investigated using high-sensitivity time-resolved fluorescence spectroscopy techniques with picosecond gating capabilities. The overall fluorescence intensity of both melanin and lipofuscin granules clearly increased with increasing donor age, the increase being most marked for melanin. In all granule populations the fluorescence decays were multiexponential with subnanosecond and nanosecond decay components. The resultant time-integrated and time-gated spectra also exhibited marked age-variations for each type of granule. Young melanin showed spectral patterns similar to those of bovine melanin, while a yellow-orange fluorescence band appeared in melanin samples from older age groups. Lipofuscin granules exhibited a blue, a yellow and an orange band whose relative amounts were age-related. The results demonstrate the potential of time-resolved techniques for discriminating fluorophores in vitro and in situ, and have confirmed results previously obtained using extraction techniques. Furthermore, the ability of this technique to identify and quantify individual fluorophores within granules may provide an important insight into the origin and development of lipofuscin within the retinal pigment epithelium and ultimately into the mechanisms of age-related retinal diseases.     

阳离子荧光敏感器的器件化问题研究

通过对石英玻片表面修饰, 制作了联有多氨基链萘基的超薄膜荧光敏感器件, 研究了它在镍、铜等金属离子水溶液及有机溶剂中的荧光猝灭现象. 发现其荧光光谱无论在水或其他有机溶剂中都存在着单体和激基缔合物(ex-cimer)的发射峰, 当处于镍离子水溶液中时, 其单体峰随离子浓度的增大出现了先增强后减弱的现象, 而激基缔合物的发光峰则仅略有减弱但变化不大. 在铜离子水溶液中其荧光的变化情况和镍离子有所不同, 对单体荧光只能观察到强度减弱的趋势, 而激基缔合物则变化不大. 比较了未联结的敏感器化合物分子在有机溶剂中荧光被铜离子猝灭的行为, 发现与其在器件表面时有很大的差别, 表明其分子结构和构象也有很大的不同.     

BEHAVIOR OF ANIONIC SURFACTANT MICELLES IN THE PRESENCE OF Al3+ AND Ca2+

The estimation of the C-potential of ionic surfactant micelles may be useful for the study of adsorption of solutes onto the micellar surface, which causes a reduction of the net electrostatic charge. This work presents results on the variation of ζ-potential of alkylsulfate and fatty carboxylate micelles with the bulk concentrations of Al³⁺ and Ca²⁺ cations. Combined with results from the literature about the effect of micellar surfactant concentration on reducing surfactant precipitation in the presence of polyvalent cations, these allow to conclude that micelles of anionic surfactants will have a higher chance of electroneutralization of their surface charge by adsorbing cations if the end functional group of the surfactant is smaller.     

PHOTOINITIATED CATIONIC POLYMERIZATION OF EPOXY MONOMERS IN THE PRESENCE OF POLY(3,4-EPOXY-1-BUTENE)

ABSTRACT

Hydroxyl-terminated poly(3,4-epoxy-1-butene) (polyEPB) is an interesting and highly useful agent for the acceleration of the photoinitiated cationic ring-opening polymerization of epoxide monomers. Kinetic investigations using real-time infrared spectroscopy have shown that the observed acceleration of the polymerization is due to two independent mechanisms. Crosslinking polymerization of epoxide monomers is accelerated due to an activated monomer mechanism that results in facile chain transfer due to interaction of the terminal hydroxyl groups of polyEPB with the growing oxonium ion chain ends. A second mechanism involving participation of polyEPB in a free radical chain induced decomposition of the onium salt photoinitiator is mainly responsible for the observed acceleration in the rate of polymerization. A large number of polymer-bound carbocationic species are generated by this mechanism that are capable of initiating polymerization of the epoxide monomer.     

PICOSECOND FLUORESCENCE SPECTROSCOPY ON INCORPORATION PROCESSES OF HEMATOPORPHYRIN DERIVATIVE INTO MALIGNANT TUMOR CELLS in vitro

Abstract— By using a highly sensitive streak-camera technique, we investigate incorporation processes of HpD into malignant tumor m-KSA cells in vitro. The picosecond decays of the total fluorescence spectra, the wavelength-resolved fluorescence decays and the time-resolved fluorescence spectra from HpD in the cells are measured as a function of the incubation time. The results show that the aggregate component of HpD which has a fast fluorescence lifetime of 100 ps and a red-shifted band of ∼ 660 nm selectively accumulates more and more in the cells with the increase of the incubation time.     

一种新型的荧光探针及其在表面活性剂溶液胶束形成过程中的应用

近年来,具有分子内共扼的电荷转移化合物用作荧光探针来研究微环境的特性得到较大的发展,由Lout坛Law等提出的p-N,N一二烷基氨基爷叉丙二睛类化合物,其吸收光谱,特别是荧光光谱具有强烈的溶剂极性依赖性,即荧光光谱的峰值波长依赖于所处环境的极性,并有良好的线性关系。     

ON THE ADSORPTION OF HYDROPHOBIC POLLUTANTS ON SURFACTANT/CLAY COMPLEXES: COMPARISON OF THE INFLUENCE OF A CATIONIC AND A NONIONIC SURFACTANT

The adsorption of the cationic surfactant dodecyl trimethyl ammonium bromide (DTAB) and of the nonionic surfactant dodecyl octaethylene glycol ether (C₁₂E₈) on four different layer silicates and their influence on the sorption processes of the fungizide biphenyl were studied. Unexpectedly, no great differences were found in comparing the adsorption of the two surfactants on the basis of physicochemical investigations, although the adsorption mechanism up to monolayer formation is fundamentally different (ion exchange and physisorption). Thus, the plateau values of the adsorption isotherms and the molar enthalpies of displacement Δ ₂₁h are of the same order of magnitude for both surfactants and the same basal spacing by intercalation is observed in the case of swelling clays. The isotherms of the hydrophobic contaminant biphenyl are of the linear Cl-type at all layer silicates and very low adsorption takes place approximately proportionally to the BET (N₂) surface area. If the surface is weakly hydrophobized by surfactants (c_surfactant<< critical;micelle concentration (CMC)), biphenyl adsorption is clearly increased. These processes can be adequately described using the distribution coefficients K and K_OC (Henry coefficient related to the organic carbon content). K_OC is hardly influenced by the type of layer silicate for DTA⁺-layer silicates, whereas the C₁₂E₈ layer silicate complexes generally show higher, but also different K_OC values. If the surfactant concentrations are above the CMC, solubilization and adsorption compete for the pollutant molecules, which leads to a significant decrease in biphenyl adsorption.