Subcellular Localization of Sulfonated Tetraphenyl Porphines in Colon Carcinoma Cells by Spectrally Resolved Imaging

Subcellular localization of the dye, 5,10,15,20-tetra(4-sul-fonatophenyl)porphine (TPPS₄) and the more hydrophobic dye, 5,10,15,20-tetra(1-sulfonatophenyl)porphine (TPPS₁), in murine colon carcinoma cells was studied by spectrally resolved imaging (SRI) combined with image processing techniques. Spectrally resolved imaging enabled the acquisition of multipixel fluorescence spectra (>10⁴) from a single cell. Demarcation of specific localization sites and segregation of the irrelevant fluorescence were based on the pixel spectra and by operating the functions of spectral similarity mapping (SSM), principal component analysis (PCA) and spectral classification. The SRI revealed the fine details of the photochemical process that clarify some aspects of subcellular damage. The SRI depicted the differences between TPPS₄ and TPPS, with respect to their initial localization and their fate at the end of the photochemical effect. The dye TPPS₄ was localized initially in lysosomal vesicles, and upon irradiation fluorescence was seen in the nucleus as well as in vesicles. Some of the vesicles were closely related to the nucleus, as resolved by SSM, PCA and spectral classification. Additional light exposure stimulated relocalization of TPPS₄ into the nucleus as well as into the nucleolus, which was clearly depicted by SSM and PCA. Spectral classification showed a third, weak residual cytoplasmic array around the nucleus. The dye TPPS, concentrated in a Golgi-like complex and was resolved in the nuclear envelope and in small vesicles: it was not redistributed into other compartments upon photosensitization. Serum supplementation to the incubation media of colon carcinoma cells treated with TPPS₄ or TPPS, did not change the localization patterns. Pixel spectra of the two dyes in the cells showed spectral shifts and expanded shoulders due to microenvironmental effects. Thus, the chemical nature of the sulfonated phenyl porphines, and not their interaction with serum proteins, was the main determinant of their binding to the lysosomes, nucleus, nucleolus, nuclear envelope or Golgi.     

Ultrafast Dynamics of o‐Bromofluorobenzene Studied by Time‐Resolved Photoelectron Imaging

Photodissociation dynamics and rotational wave packet coherences of o‐bromofluorobenzene are studied by femtosecond time‐resolved photoelectron imaging (see figure). The decay of different photoelectron rings shows the population decay of states from which the lifetimes of different states are determined. The variation of photoelectron angular distributions reflects the evolution of rotational coherences.

     

五员碳环、氮环和磷环比较的量子化学研究

用密度泛函(DFT)理论中的B3LYP和从头算(abinitio)理论中UHF,在6-31G基组水平上,对五员碳环、氮环和磷环进行几何优化计算,由所得结果讨论了分子的成键情况,对两类环(一类是C5H5、N5、P5;另一类是C5H5-、N5-和P5-)的相对稳定性分别作比较。结果表明:有机五员碳环比无机五员氮环、磷环稳定,而五员氮环与五员磷环相比,磷环更稳定。     

Spectrally tunable uncaging of biological stimuli from nanocapsules

This communication describes the first uncaging of stimuli in the far red, wavelengths that have much less of an adverse affect on cellular systems, via photolysis of photosensitized nanocapsules.     

Spectrally resolved fluorescence imaging of human colonic adenomas

Native fluorescence (autofluorescence) of human tissues can be a valuable source of diagnostic information for detecting premalignant and malignant lesions in the human body. Digital imaging of autofluorescence may be useful for localization of such lesions during endoscopic examinations. Tissue fluorescence of 31 adenomatous polyps obtained from 16 patients has been excited in vitro using the 325 nm line of a He-Cd laser. Digital images of the autofluorescence are recorded in six spectral bands. This study provides new data about the spatial distributions of autofluorescence intensities emitted in different spectral bands by colonic adenomatous lesions and normal colonic mucosa. Areas characterized by autofluorescence intensity lower than in normal mucosa are found for a majority of the polyps under study. The observed patterns of spatial distribution differ for the different spectral bands and for different polypoid lesions. No inverse correlation is found between the emission intensity and the thickness of colonic mucosa. The results indicate the spectral bands most useful for diagnostic applications and demonstrate the complexity of the optical processes involved in shaping both the spectra and intensities of the autofluorescence.     

Resolved pseudo-raman spectrum of ovuline albumin

A series of resolved pseudo-Raman peaks, in harmonic position, is obtained from ovuline albumin. The spectrum is a function of the water layer bonded to the molecule. Data are in agreement with the theory of “electromagnetic molecular electronic resonance”.     

Time Resolved Chromatographic Study and Characterization of Gas-Solid Interfaces

The reversed flow – inverse gas chromatography is a simple and fast technique for the determination of kinetic and energetic parameters, for the degradation diagnosis describing the action of one or two gases simultaneously on a solid surface. The RF-IGC (or RF-GC) method was used to measure directly from experimental data, not only kinetic physicochemical quantities, but also adsorption energies, local monolayer capacities, local adsorption isotherms, the probability density function for the adsorption energies as distributed over the experimental time. This method has been applied by using n-hexane as probe gas and magnesium oxide, chromium oxide, silicon oxide and cadmium sulfide as solid adsorbents. In that way, one can be led to the characterization of heterogeneous surfaces and throw some light to the mechanism of heterogeneous reactions taking place in nature, as the deterioration of monuments and works of art by air pollutants, or in industrial processes.     

Potential - Resolved Electro Chemiluminescence of Luminol

Since the electrogenerated chemiluminescence (ECL) of luminol was first reported in 1929 by Harvey, a number of papers have been published for mechanistic and analytical studies of luminol ECL.     

二甲胺同步辐射光电离解离机理的质谱研究

利用同步辐射光源,结合飞行时间质谱,在超声射流冷却条件下研究了(CH_3) _2NH(DMA)的光电离解离机理。实验观察到四种主要离子(CH_3)_2NH·~+, CH_3NH~+CH_2,CH_2NH_2~+和CHNH~+,质荷比分别为m/z = 45,44,30和28。四种 离子的出现势（AE）分别为8.26,9.52,11.93和11.27 eV,其中分子电离热IP = （8.26 ± 0.01） eV,计算得到分子离子的生成热Δ_fH~o = 778.55 kJ/mol。 分析表明离子CH_3NH~+CH_2来自母体离子的α去H过程。其他碎片离子由后续逐级 解离去H反应以及脱CH_3通道生成。