激光光热光谱分析特性比较

本文详细比较了激光光热偏转,激光热透镜和激光光热折射光谱法的基本原理,光学构型和分析化学特性。并讨论了激光光热光谱法的分析现状和应用潜力。     

MXenes的制备及其光热性能在癌症治疗中的应用

近年来，过渡金属碳化物和氮化物(MXenes)作为一种新型二维材料以其独特的晶体特征和结构特性受到越来越多的关注，尤其是在能源、催化、生物医学等领域得到广泛应用。MXenes独特的晶体结构和表面特性赋予其优异的电子、光学、磁性等理化性能。此外，MXenes较大的比表面积和较高的光热转换效率，使其在生物医学领域尤其是肿瘤治疗方面得到大量应用。本文主要介绍了MXenes的合成方法和光热特性，重点总结分析了MXenes的光热性能在癌症治疗中的应用等研究进展，并提出了MXenes在癌症治疗中存在的潜在挑战和前景。     

光敏玻璃原理及应用

介绍了光敏玻璃的制作方法，光热化学反应原理及其各种用途。讨论了组成，光照时间及热处理温度对光敏玻璃的透光率、颜色、光敏特性等物理，化学性质的影响。     

光热显微术:基于光吸收的单分子成像技术

光热显微术是近年来获得广泛关注和长足发展的一种新型光学显微成像技术,能够实现单个纳米粒子甚至单分子的免标记光学成像。其成像原理是利用先进的光学方法探测单分子或单纳米粒子吸收特定波长激发光后所产生的局域温度和介质折射率的微小变化,从而定量研究观测对象的光热特性。由于无辐射弛豫是激发态分子回到基态的优势过程,分子的光热特性相比于荧光特性更具有普遍意义。凭借无需标记、高灵敏度和信号稳定等优点,近十年来,关于单分子和单纳米粒子的光热显微成像研究不断取得突破,并在纳米科学和生命科学等领域获得越来越多的发展和应用,展现出了蓬勃的生命力和良好的发展前景。本文重点综述了光热显微技术的成像原理、发展历程、技术特色以及系统优化方法,列举了光热成像在活细胞研究和生物学领域的应用,最后总结了光热成像的优缺点并分析其主要面临的挑战以及未来的发展趋势,希望吸引更多的研究人员加入到这一新技术的研究队伍中来。     

特异性靶点光热剂在光热治疗领域的研究进展北大核心CSCD

光热疗法是一种利用光热剂将光能转变为热能,通过局部加热并触发生化过程来杀死肿瘤细胞的一种肿瘤治疗方法。由于照射光具有易聚焦和易调整的特性,因此光热治疗能以非侵入的方式,直接、精准地在局部进行治疗。本文对不同类型的光热剂的最新进展进行了总结,根据识别位点的不同,从“细胞外靶点”、“细胞上的靶点”和“细胞内靶点”三个方面,对典型的特异性靶点光热剂进行了详细的介绍。最后讨论了基于光热转换纳米材料的肿瘤光热治疗在临床应用方面面临的局限性和挑战。     

固体表面化学发光分析 Ⅰ.不渗透阻挡技术的应用和研究

本文应用不渗透阻挡技术在固体基质上保持恒定的化学发光区域，实现了固体表面化学发光分析，并对固体表面化学发光特性，发光的均匀性和重视性，固体基质的选择和纯化等方面进行了研究，测定了１３种无机及生物活性物质固体表面化学发光的线性范围及检测限。由于此法克服了固体基质荧光分析和固体表面室温磷光分析的散射光背景的影响，获得了更高的信噪比和更好的检测限。     

高效毛细管电泳中的激光光热检测技术

集中介绍了激光光热分析在高效毛细管电泳检测上的应用；分析了各种光热检测构型的特点，阐述了影响光热信号的各种因素；指出了激光光热检测技术在高效毛细管电泳中的应用前景。     

谷胱甘肽修饰金纳米棒的制备及与Cu~(2+)的作用

制备了谷胱甘肽(GSH)功能化的金纳米棒复合材料,根据金纳米棒的等离子体吸收峰对其组装排列敏感的特性,研究了功能化的金纳米棒在不同p H值下的组装行为及与Cu2+离子作用后引起的聚集程度、排列方式和光学吸收等变化.同时,测试了纯金纳米棒和谷胱甘肽修饰的金纳米棒分别与铜离子作用后所得复合材料的光热转换性能.结果表明,相对于纯金纳米棒材料强的光热转换效应,铜离子能明显降低复合材料的光热转换效应,与其它金属离子比较,GSH修饰的金纳米棒的等离子光学特性对铜离子具有选择性的变化.     

高分子固体电解质材料研究进展

高分子固体电解质材料由于具有优良的成膜性和粘弹性等特点，。近年来得到了很大的发展。本文综述了高分子固体电解质材料的电性能，离子传导特性，提高其性能的途径及近期发展，并对其发展前景作了简要的探讨。     

催化反应热诱导激光光偏转分析法测定尿素

报道用催化反应热诱导激光光偏转法测定痕量尿素。发现将脲酶制成一定浓度的乙醇浓液能显著地增强激光光偏转信号强度。探讨了增强作用机理以及光偏转号强度与尿素浓度的关系，并应用于尿样中尿素含量的测定，结果满意。     

Dithizone and its oxidation products: a DFT, spectroscopic, and X-ray structural study

Air oxidation of ortho-fluorodithizone resulted in the first X-ray resolved structure of a disulfide of dithizone, validating the last outstanding X-ray structure in the oxidation of dithizone, H(2)Dz, which proceeds via the disulfide, (HDz)(2), to the deprotonated dehydrodithizone tetrazolium salt, Dz. Density functional theory calculations established the energetically favored tautomers along the entire pathway; in gas phase and in polar as well as nonpolar solvent environments. DFT calculations using the classic pure OLYP and PW91, or the newer B3LYP hybrid functional, as well as MP2 calculations, yielded the lowest energy structures in agreement with corresponding experimental X-ray crystallographic results. Atomic charge distribution patterns confirmed the cyclization reaction pathway and crystal packing of Dz. Time dependent DFT for the first time gave satisfactory explanation for the solvatochromic properties of dithizone, pointing to different tautomers that give rise to the observed orange color in methanol and green in dichloromethane. Concentratochromism of H(2)Dz was observed in methanol. Computed orbitals and oscillators are in close agreement with UV-visible spectroscopic experimental results.     

Detection and semiquantitative determination of bismuth(III) in water on immobilized and plasticized polyurethane foams with some chromogenic reagents

Polyurethane foams immobilizing 1,2-di-(2-fluorophenyl)-3-mercaptoformazan (F(2)H(2)Dz) and dithizone (H(2)Dz) have been used for the detection of bismuth(III) in water via batch, dynamic and pulsated column modes of extraction. The detection limits of bismuth(III) with the F(2)H(2)Dz- and H(2)Dz-immobilized foams were found to be 0.01 and 0.02 mug ml(-1) respectively. Lower concentrations (相似文献   

Anomalous line broadening in the ESR spectra of copper(ii) dithizonate

The structure of the copper(ii) complex with dithizone (H₂Dz) was studied by ESR spectroscopy. The lines of the ESR spectra of the Cu(HDz)₂ complex in solutions are so broad that the superhyperfine structure (SHFS) from the ligand atoms is unobservable and even the hyperfine structure (HFS) from the copper nuclei is poorly resolved. In polycrystalline magnetically dilute powders with the ratio Ni(HDz)₂ : Cu(HDz)₂ = 60 : 1, the SHFS from the N atoms is well resolved in both perpendicular and parallel orientations. The copper(ii) complex with dithizone has a square-planar structure in both liquid solutions and Ni(HDz)₂ matrix. Reasons for the unusual linewidths in the ESR spectra of Cu(HDz)₂ are discussed.     

Use of photothermal deflection spectrometry (PDS) for studies of analytes in aqueous solutions

Summary A crossed-beam photothermal deflection spectrophotometer (PDS) instrument was built, evaluated and applied to the determination of lanthanide neodymium. A dye laser filled with rhodamine 6 G and pumped by an argon ion laser at 514 nm was operated with outputs between 4 and 500 mW at the cuvette position and chopped at 2 Hz. The deflection of a He-Ne probe laser beam, crossing the exciting dye laser, was measured by a two-dimensional position sensitive device and two lock-in amplifiers. The setup was evaluated with a solid carbon sample and the liquids toluene and Nd³⁺/HClO₄.A calibration curve for Nd³⁺ in HClO₄ was obtained and the limit of detection (LOD) for Nd³⁺ was determined to be 2·10^–6 mol/l. This LOD is, on the one hand, by 2 orders of magnitudes lower than the value obtained with the Cary 2400 spectrophotometer and, on the other hand, this transverse PDS technique is highly competitive to collinear thermal lensing and laser-induced photoacoustic spectroscopy.     

Molecular photochromic systems: a theoretical and experimental investigation on zinc(II) dithizonate

Zinc(II)‐dithizone based molecular systems [Zn(HDz)₂] are intriguing candidates for the development of optical devices thanks to their interesting photochromic and nonlinear optical properties. In the present work, the behavior of Zn(HDz)₂ in different solvents was investigated by a combined theoretical and experimental approach. In particular, solutions of both dithizone (H₂Dz) and Zn(HDz)₂ were analyzed by optical absorption spectroscopy and nuclear magnetic resonance (NMR) techniques, with particular attention to structure–properties relationships. Density functional and time‐dependent density functional calculations were performed on the stable and the activated forms of the complex, obtaining information on the energetics of their interconversion, as well as on the nature of their electronic excitations. Copyright © 2007 John Wiley & Sons, Ltd.     

Determination of Silver with On-Line Preconcentration Using Dithiozone Chelate and Carbon Nanotubes for Preconcentration with Detection by Flame Atomic Absorption Spectrometry

A novel flow injection system incorporating a micro-column packed with carbon nanotubes (CNTs) as an adsorbent has been applied to the on-line preconcentration of trace silver with detection by flame atomic absorption spectrometry. Silver is first chelated by dithizone (H₂Dz), then retained on the CNTs surface and afterward quantitatively eluted by methanol. Influencing parameters, including the concentration of reaction reagent, enrichment variables, and elution variables were investigated. The adsorption mechanisms of Ag-H₂Dz chelate retained onto the CNTs surface have also been studied. By loading 6.9 mL sample solution, a linear calibration graph is obtained within the range of 3–120 µg L^?1 with R of 0.9996, and a detection limit (3σ) of 0.8 µg L^?1 is achieved, along with a precision of 1.6% R.S.D. at the 30 µg L^?1 level (n = 7). The dynamic sorption capacity of CNTs for silver is 122 mg g^?1. The procedure is demonstrated by measurement of spike recovery in a series of water samples, giving rise to spike recoveries in the range of 96.8–99.7%.     

Studies with dithizone : Part 26. The interaction of thallium(III) with solutions of dithizone in organic solvents

The strong oxidising capacity of thallium(III) dominates its reaction with solutions of dithizone (H₂Dz) in organic solvents. When carbon tetrachloride is used as solvent, the unstable thallium(III) complex Tl(HDz)³ is found in the organic phase but it very quickly disproportionates to the thallium(I) complex [Tl(HDz)], and bis-1,5-diphenylformazan-3-yl-disulphide. This reaction is notably faster in chloroform, in which thallium(I) dithizonate is the first identifiable product. In contact with an acidic aqueous phase, thallium(I) dithizonate is reverted to regenerate dithizone in the organic phase and Tl⁺ ions appear in the aqueous phase. Organic solutions of the disulphide disproportionate spontaneously by first-order kinetics to give an equimolar mixture of dithizone and the mesoionic compound, 2,3-diphenyl-2,3-dihydrotetrazolium-5-thiolate: this change is much slower in carbon tetrachloride than in the more polar chloroform and is catalysed by both Tl⁺ and Tl³⁺. If thallium(III) is present in excess, the mesoionic compound is the principal oxidation product of the dithizone although a dication may also be formed. The mesoionic compound does not react with thallium(I) but forms a water-soluble 2:1 complex with thallium(III); partition of this complex into the organic phase is uninfluenced by chloride ions. Because of the large number of competing reactions, the composition of the reaction mixture at any stage of the reaction between thallium(III) and dithizone depends on the relative concentrations of the components, the order in which they are brought together, the time elapsed after mixing, the pH of the aqueous phase, and the nature of the organic solvent.     

PHOTOTHERMAL DEFLECTION SPECTROSCOPY OF PHOTOSYNTHETIC PIGMENTS in vivo and in vitro

Abstract— This Technical Note describes the design of a photothermal beam deflection apparatus which allows the easy and rapid measurement of thermal dissipation of absorbed light energy in various photosynthetic materials including whole plant leaves. This system is based on the "mirage effect" in which the refractive index gradient induced in a fluid in contact with the sample, irradiated with an intensity-modulated light, causes the periodic deflection of a laser beam parallel to the sample surface. The deflection of the probe laser beam is detected by a position sensor, the output of which is processed by a lock-in amplifier. Photothermal deflection signals can be monitored in vivo in intact leaves placed in various (liquid or gaseous) environments with a satisfactory signal-to-noise ratio between 100 (in water) and 50 (in air) at low modulation frequencies (ca 30 Hz). It is shown that this new and simple photothermal technique is a very sensitive tool for the measurement of absorption spectra of photosynthetic pigments both in vivo (leaves, algae or chloroplasts) and in model systems (Langmuir-Blodgett and solid films of chlorophyll).     

The limit of detection in transversal photothermal deflection spectroscopy with light scattering samples

The limit of detection for the 4,6 dinitro-orthocresol (DNOC) pesticide, including small latex particles as light scattering samples in water as suspending medium, has been determined for the transversal photothermal deflection technique. The results where compared to conventional spectrophotometry. In the photothermal deflection experiments performed with a continuous Ar⁺-excitation beam (=363.8 nm) a LOD of 0.8 g/l is achieved for the DNOC in water.Awarded poster prize     

Effect of Anions on the Development of Color Reactions of Cadmium, Lead, and Mercury with Dithizone and 4-(2-Pyridylazo)resorcinol on a Fibrous Material Filled with the Anion Exchanger AV-17

The effect of nitrates, chlorides, iodides, sulfates, thiosulfates, thiocyanates, acetates, tartrates, nitrilotriacetates, and ethylenediaminetetraacetates in the sorption of Cd(II), Pb(II), and Hg(II) and their subsequent determination with dithizone and 4-(2-pyridylazo)resorcinol (PAR) on the solid phase of a fibrous anion-exchange sorbent filled with AV-17 was studied. The dependences of the analytical signals of complexes adsorbed on the solid phase on the concentration of anions in the solution and on the stability of anionic complexes were revealed. The analytical signals in the sorption and determination of Cd, Pb, and Hg with dithizone and PAR on the solid phase were maximum for iodide and thiosulfate complexes. Conditions of the sorption of Cd(II), Pb(II), and Hg(II) were found for their subsequent total and separate determination with PAR and dithizone.