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The peculiarities of the decoration of gravure imprints on cardboard using fluorescent inks are considered. The influence of the number of fluorescent impurities added to gravure printing ink on the optical indicators of printed image quality, particularly optical density, and gloss, is investigated. Increasing the number of fluorescent impurities added to the ink from 10 to 30% helps to increase the gloss on imprints from 2 to 15 units. Conducted thermogravimetric studies show the resistance of fluorescent imprints to the influence of temperatures during drying in the printing process. The topography of the surface of the substrates and its influence on the quality of imprints is studied. Conducted electron microscopic studies of imprints obtained with inks with different amounts of fluorescent impurities show their uniform distribution on the surface of the substrate. Studies of the fluorescence spectra of the ink and the imprints formed by it confirm the phenomenon of an increase in the intensity of the glow of printed images. The studies confirm the well-known influence of substrate roughness on the smoothness of gravure imprints. It is established that the absence of significant macro irregularities on the surface of Koppargloss FBB cardboard is due to the presence of two coating layers. Analysis of the surface profiles of FBB cardboard shows that its roughness parameter (Ra = 0.424 μm) is three times smaller compared to Incada Silk C GC1 cardboard (the roughness parameter Ra = 1.28 μm), with a single-layer coating. Such a pattern is also preserved on the imprints, which is reflected in their quality accordingly. Studies show that for imprints on GC1 cardboard, the average ΔE value is 2.23, for imprints on FBB cardboard, the average ΔE value is 3.71, which is due to the presence of double coating. The factors that can influence the process of fluorescence of printed images are outlined. The technological characteristics of inks for gravure printing on packaging are described. [ABSTRACT FROM AUTHOR]

We characterized γ-cystathionase, rhodanese and 3-mercaptopyruvate sulfurtransferase activities in various regions of human brain (the cortex, thalamus, hypothalamus, hippocampus, cerebellum and subcortical nuclei) and human gliomas with II to IV grade of malignancy (according to the WHO classification). The human brain regions, as compared to human liver, showed low γ-cystathionase activity. The activity of rhodanese was also much lower and it did not vary significantly between the investigated brain regions. The activity of 3-mercaptopyruvate sulfurtransferase was the highest in the thalamus, hypothalamus and subcortical nuclei and essentially the same level of sulfane sulfur was found in all the investigated brain regions. The investigations demonstrated that the level of sulfane sulfur in gliomas with the highest grades was high in comparison to various human brain regions, and was correlated with a decreased activity of γ-cystathionase, 3-mercaptopyruvate sulfurtransferase and rhodanese. This can suggest sulfane sulfur accumulation and points to its importance for malignant cell proliferation and tumor growth. In gliomas with the highest grades of malignancy, despite decreased levels of total free cysteine and total free glutathione, a high ratio of GSH/GSSG was maintained, which is important for the process of malignant cells proliferation. A high level of sulfane sulfur and high GSH/GSSG ratio could result in the elevated hydrogen sulfide levels. Because of the disappearance of γ-cystathionase activity in high-grade gliomas, it seems to be possible that 3-mercaptopyruvate sulfurtransferase could participate in hydrogen sulfide production. The results confirm sulfur dependence of malignant brain tumors. [ABSTRACT FROM AUTHOR]

Abstract: The RP-HPLC method for a simultaneous separation and quantitation of the dinitrophenyl derivative of cystathionine (N,N′-di-DNP) in biological samples together with GSH, GSSG, cysteine and cystine, provides a very useful tool for investigation of the transsulfuration pathway in biological samples, at the same providing results which reflect the redox status (GSH/GSSG ratio) and the potential of the generation of H2S. An application of the method for the study of the process of transsulfuration in various human brain regions shows the presence of cystathionine in all the investigated regions; it also demonstrates that cystathionine levels vary greatly between particular regions. The highest level in the thalamus and the lowest in the cerebellum were associated with respectively a low or high γ-cystathionase activity, and at the same time, a high cysteine and GSH level in the thalamus and a low value in the cerebellum. Based on the above results, one may suggest a regulatory mechanism responsible for inhibition of the CGL activity at high concentration values of cysteine and/or GSH. Simultaneous determinations of GSH and GSSG levels allow for determining the GSH/GSSG ratio, which reflects tissue redox status. The method may be also employed in determining the activity of γ-cystathionase and cystathionine-β synthase. [Copyright &y& Elsevier]