头孢噻肟钠与牛血清蛋白相互作用的光谱特征

用光谱法研究头孢噻肟钠（CS）和牛血清蛋白（BSA）在模拟生命体生理条件下相互作用的特征.结果表明CS主要以静态猝灭方式使BSA的荧光强度显著降低;利用同步荧光法研究了CS和BSA作用后牛血清蛋白的构象发生了变化;求得不同温度下二者的结合常数和结合位点数,探讨了微量金属离子对实验体系结合常数的影响,并根据热力学参数确定了CS和BSA之间主要依靠静电力结合.根据Froester非辐射能量转移机理,测定了CS与BSA相互结合时的作用距离2.56nm,表明BSA与CS之间发生了非辐射能量转移.     

芬布芬-铜（Ⅱ）-牛血清白蛋白相互作用的光谱法研究

模拟生理条件下,应用荧光光谱法研究了芬布芬对牛血清白蛋白,铜（Ⅱ）对牛血清白蛋白以及铜（Ⅱ）对芬布芬和牛血清白蛋白荧光光谱特性的影响.实验表明：铜（Ⅱ）和芬布芬均可使牛血清白蛋白的荧光强度发生静态猝灭,并且在铜（Ⅱ）存在下,芬布芬对牛血清白蛋白的荧光猝灭作用显著增强.根据荧光猝灭双倒数图计算芬布芬和牛血清白蛋白的结合常数为8.44×104,结合位点数为0.97.荧光猝灭双倒数图计算的结果表明,芬布芬和牛血清白蛋白之间的结合常数和结合位点数均随铜（Ⅱ）浓度的增大而增大.很据三者结合反应的研究,进一步探讨了芬布芬、铜（Ⅱ）在生物体内与蛋白质相互作用的机理.     

In Light of Recent Developments,Application of Fluorescence Spectral Analysis in Tumor Diagnosis

Abstract

This paper reviews the background to cancer tumors. Fluorescence spectral analysis has been quantitatively applied to the detection of protoporphyrin IX (Pp‐IX) in transplanted squamous cell carcinoma (SCC) tissue and intra‐operative brain astrocytoma (glioblastoma) tissue after the administration of 5‐aminolevulinic acid (5‐ALA). Coincidence with the emission spectra of Pp‐IX incorporated into the tumor tissues (cryo‐sections) and a standard Pp‐IX in the miceller solution was confirmed. A calibration curve of the fluorescence intensity of Pp‐IX against a known concentration standard of Pp‐IX was established. From the fluorescence detection method (calibration curve), it was found that the longer alkyl‐chain length (methyl‐ and hexyl‐) 5‐ALA induced Pp‐IX in the SCC tissue. Furthermore, an ultrasound treatment enhanced the uptake of Pp‐IX during the topical administration of 5‐ALA derivatives. In the case of intra‐operative observation for the fluorescence intensity of Pp‐IX in the brain astrocytoma tissue, this quantitative detection in the cryo‐section demonstrated the intra‐operative observation for the fluorescence intensities (?, +/?, +, ++, +++) diagnosis was correlated closely with the grades of astrocytoma. The intensity increased exponentially with the cancer grades. In future, fluorescence spectral diagnosis of Pp‐IX in the tumor will be very useful for other clinical diagnosis of tumors using 5‐ALA.     

Application of Spectroscopy in the Study of Glassy Solids,Part II. Infrared,Raman, EPR,and NMR Spectral Studies

Abstract

The current review of spectroscopic studies in the glassy state concludes in this part with the consideration of wavelengths in the infrared region and below, Of all the spectral regions, the infrared is the most extensively studied, as can be readily seen from a statistical appraisal of interest, a s judged from the number of publications in the various spectral regions, given in Fig. 7 in the final section of this paper.     

Fluorescence Correlation Spectroscopy (FCS): A Promising Tool for Biological Research

Abstract

Fluorescence correlation spectroscopy (FCS) is an important biophysical technique. FCS is currently being used in many areas of biology to solve several scientific problems. Its properties such as detection at the single molecular level, higher sensitivity, and use of lower sample volume make FCS a promising molecular diagnostic tool. The promising applications of FCS extend from DNA kinetics/dynamics studies to the comprehensive understanding of receptor–ligand interactions. In this article, we review various promising biological applications of FCS.     

Photo- and electroluminescence of nitrogen isoelectronic traps in GaAs1–xPx

The variation with temperature of the charge on the surface of NaCl single crystals has been measured directly by means of vibrating capacitor probe. The charge is negative at room temperature, in agreement with theory based on values of the free energy of vacancy formation, decreases with increase of temperature in two stages to a zero value at the isoelectric temperature, and then becomes positive. Values of isoelectric temperature obtained on surfaces are consistent with those obtained by experiments on charged dislocations, which suggests that surfaces could be used to obtain accurate values of the free energy of formation of cation and anion vacancies.     

High pressure and emission spectra of Eu3+ in L-EuBO3

Effects of the high pressure on the emission spectra of Eu³⁺-activated L-EuBO₃ were considered at room temperature up to 100 kbar. The position of five 0–2 lines in the ⁵D₀→⁷F₂ transition region was determined. The pressure does not have the same effect on all these lines. In four of them, high pressure induced a red shift with different shift rates:+0.0022,+0.0035,+0.0034 and+0.0027 nm kbar^?1, respectively, whereas in the last one, high pressure induced a blue shift with shift rate?0.0034 nm kbar^?1. Possible reasons for the mentioned pressure effects on the line positions were considered.     

Extrinsic fluorescence as a sensitive method for studying photo-degradation of high density polyethylene correlated with mechanical stresses

A fluorescence probe, inserted in a solid polymeric matrix, is used to follow the first steps of photo-degradation by fluorescence spectroscopy. The competition between cross-linking and chain breaking during the degradation entail physical modifications in the macromolecular chains. These modifications usually followed by gel permeation spectroscopy can be studied by extrinsic florescence spectroscopy. Due to the high sensitivity of the fluorescent probe to the polymer matrix evolution, all the structural modifications can be investigated. In particular during the first photo-degradation steps, a correlation with activation energy necessary to the chain mobility is used to understand the sensibility of the fluorescent probe.     

Analytical Scheme for the Direct Graphite-Atomizer/Flame Atomic Absorption Spectrometric Determination of Fifteen Trace Elements in Toenails for Biological Monitoring

An analytical scheme for the determination of up to fifteen trace elements in nails and hair has been proposed. Samples were solubilized by means of aqueous tetraalkylammonium hydroxide (alkyl = methyl or ethyl). Cadmium, Cr, Cu, Fe, Mn, Pb and Zn were determined by pulse-nebulization flame AAS, employing the Slotted Tube Atom Trap (STAT) for Cd and Pb. Suitable chemical modifiers have been applied in electrothermal AAS (ETAAS) determinations of Cd and Pb (ammonium hydrogen phosphate), As, Sb, Se and Sn (palladium), while no modifier was needed in determinations of Al, Co, Cr, Mn, Mo and Ni. Calibration was performed by means of matrix-matched standards and the technique was verified by standard additions, comparison with neutron activation and analysis of hair reference material. The usefulness of this technique for occupational exposure monitoring is briefly discussed.     

Applicability of Spectroscopic Methods to the Determination of Aluminium in Biological Samples

A comparative investigation was carried out of the suitability of atomic absorption spectrometry and of emission spectrography with hollow cathode and arc excitation sources for determination of aluminium in biological samples. The three methods give reliable results. Hollow cathode emission spectrography was found to be influenced to a lesser extent by matrix effects than the other two techniques. On the other hand atomic absorption spectrometry presents some remarkable advantages insofar rapidity of analysis and detection limits are concerned.