Search

Abstract: The automated, computer-aided method for differentiation and classification of malignant (M) from benign (B) cases, by analyzing the UV/VIS spectra of pleural effusions is described. It was shown that by two independent objective features, the maximum of Katz fractal dimension (KFDmax) and the area under normalized UV/VIS absorbance curve (Area), highly reliable M–B classification is possible. In the Area–KFDmax space M and B samples are linearly separable permitting thus the use of linear support vector machine as a classification tool. By analyzing 104 samples of UV/VIS spectra of pleural effusions (88 M and 16 B) collected from patients at the Clinic for Lung Diseases and Tuberculosis, Military Medical Academy in Belgrade, the accuracy of 95.45% for M cases and 100% for B cases are obtained by using the proposed method. It was shown that by applying some modifications, which are suggested in the paper, the accuracy of 100% for M cases can be reached. [Copyright &y& Elsevier]

Abstract: Commercial essential oils of Thymus vulgaris L., Rosmarinus officinalis L. and Origanum vulgare L. were chemically characterized by GC, GC/MS analyses. The antilisterial activity of the oils, and the sub-lethal concentration of lactic acid were established by the agar-well diffusion method. The bactericidal kinetics of the diluted oils (50ppm, 100ppm, 200ppm and 300ppm) and their mixtures with 50ppm of lactic acid were determined by optical density (OD600) measurements. The results suggest that a sub-lethal dose of lactic acid noticeably increased the antilisterial activity, especially of rosemary and thyme oils, but that the synergistic effects were reduced with higher concentrations of oils. [Copyright &y& Elsevier]

Abstract: Acute toxicity in vivo toward rats, of nineteen N-alkyl and N-cycloalkyl fluorocetamides [F–CH2–C(O)–NH–R] was correlated with their structure-dependent properties. Used descriptors are: molecular weights (M w) and heat of formation (ΔH f) of compounds; molar refractivity (CMR), lipophilicity (Clog P), Broto lipol values, virtual log P, molecular lipophilic potential (MLP), Van der Waals surfaces (VdW SAS) and hydropathicity surface (ILM) of whole molecules; Taft steric parameters (E s); E s values with Hancock corrections () and Verloop sterimol (B 5) and (L) parameters of alkyl and cycloalkyl residues; superdelocalizabilities and electron densities on the [NH–C(O)–CH2–F] fragment. Strong quantitative structure–activity relationships were assessed. Obtained correlation suggested that lipophilicity, shape and bulkiness of the alkyl and cycloalkyl substituents, particular nearest vicinity of the amide nitrogen, as well charges on the amide moiety are the main factors that influence on the acute toxicity of studied compounds toward rats. Mechanism of toxic action was proposed. [Copyright &y& Elsevier]

Herein, we report the synthesis and characterization of nine 6-hydroxy-4-methyl-3-pyridinium-2-pyridone based azo dyes, wherein, eight of them being novel. Used building blocks ensured water solubility of six dyes and made them adequate to be used for dyeing in an alkaline environment contrary to the traditional application of arylazo pyridone dyes. The peculiarity of the compounds arises as they exhibit zwitterion-hydrazone equilibrium and shift from neutral to cationic dyes. It is shown that the equilibrium strongly depends on the electronic effects of the p -substituent in the phenyl moiety, as well as, pH values of the solutions. The screening of the dyeing process (by using multifiber fabric) suggested that synthesized compounds are most eligible for dyeing wool and diacetate fabrics at a pH of 8.5. Furthermore, 100% wool and diacetate fabrics were dyed and used for the dyeing assessment. A comprehensive study between dye architectures and fiber dyeing was performed. The interplay of various interactions, responsible for the dye-fiber binding, has been proposed, bearing in mind both, dyes' and fibers' structures and pH dependency. Namely, dye-wool interactions are mostly based upon charge assisted hydrogen bonds, wherein these interactions are strengthened by C–H··· π contact when dyes are affixed to diacetate. The specific nature of the dye is affected by the electronic effect of the p -substituents of the phenyl moiety, upon which, a detailed study on fibers affinity towards zwitterionic and/or hydrazone forms has been outlined. Most of the dyed fabrics exhibit good to excellent ultraviolet protection, while dyed diacetate shows good washing fastness. [Display omitted] • Nine pyridinium pyridone arylazo dyes are synthesized and characterized. • The screening of dyeing was performed on multifiber fabric at three pH values. • Dyes are most eligible for dyeing wool and diacetate at pH value 8.5 • The adhesion of dyes correlates well with the share of hydrazone tautomeric form. • The electronic substituent effects play a significant role in the dye-fiber binding. [ABSTRACT FROM AUTHOR]

Seven novel azo dyes with 2-pyridone and dihydropyrimidinone moieties have been synthesized and thoroughly characterized. The azo-hydrazone tautomerism has been investigated by experimental and theoretical approaches. The optimizations of geometries have been performed with density functional theory (DFT). The vibrational and NMR spectra were calculated and correlated with experimental ones. Furthermore, quantum chemical descriptors were calculated and MEP maps were plotted to determine biological reactivity of dyes. The antioxidant assay evinced that 5 , 6 and 7 are promising antioxidant candidates. In vitro cytotoxic activity was studied against three malignant cell lines: prostate adenocarcinoma (PC-3), lung carcinoma (A549) and chronic myelogenous leukemia (K562), as well as against human normal lung fibroblasts (MRC-5), using MTT assay. Examination of cytotoxic effects on human cancer cell lines showed the concentration dependent cytotoxicity of all investigated compounds. The K562 cells were the most sensitive to the cytotoxicity of the compounds 3 , 5 and 6 , wherein compound 5 was particularly prominent and selective in cytotoxic action between K562 (24.97 μM) and PC-3 (48.98 μM) cancer cells, and normal MRC-5 (91.11 μM) cells. Moreover, the cell cycle analysis of compound 5 was examined in K562 cells, by flow cytometry, to study its mechanism of anticancer action. Finally, in silico evaluation of physicochemical parameters, druglikeness and ADME properties showed that investigated compounds are orally bioavailable with no permeation to the blood brain barrier. Image 1 • Novel azo pyridone dihydropyrimidinone based dyes are synthesized and characterized. • Experimental and DFT approaches confirm that the most stable tautomer is hydrazone. • New structures exhibited promising anticancer and antioxidant properties. • Dyes show concentration dependent cytotoxicity against tested cancer cells. • Novel dyes may serve for further development of new anticancer drugs. [ABSTRACT FROM AUTHOR]

A series of nine 5-(4-substituted phenylazo)-3-amido-6-hydroxy-4-methyl-2-pyridones were synthesized and characterized by FT–IR, 1H and 13C NMR, UV–Vis, and PL spectroscopy. Photophysical properties of the dyes were examined in solvents of various polarities and at different pH values. The solvent effects on the absorbance and emission spectral shift were analyzed using Lippert–Mataga, Reichardt–Dimroth and Kamlet-Taft equations. Moreover, UV–Vis absorption and emission frequencies were correlated with Hammett substituent constants applying the linear free energy relationships. DFT calculations of the investigated dyes were accomplished to determine their structural and electronic properties. Image 1 • The absorption and emission spectra of nine arylazo pyridone dyes were recorded. • The solvent effects on the absorbance and emission spectral shift were analyzed. • The conformational analysis showed that the investigated dyes are in hydrazone form. • The existence of two conformational forms of hydrazone tautomer was confirmed. • Excellent correlations between computational and experimental data were established. [ABSTRACT FROM AUTHOR]

Thermal degradation properties of 5-(4-substitutedphenylazo)-3-amido-6-hydroxy-4-methyl-2-pyridones and 5-(4-substitutedphenylazo)-3-cyano-6-hydroxy-4-methyl-2-pyridones dyes, differing in electron withdrawing and electron donating substituents in para -position of diazo components were examined. The structure of the synthesized compounds has been confirmed by 1H NMR,13C NMR, FTIR, UV–Vis and XRD analysis techniques. The results obtained with thermogravimetric analysis (TGA) – derivative thermogravimetry (DTG) and differential thermal analysis (DTA) were combined with GC-mass spectral fragmentation to obtain thermal decomposition mechanism. Non-isothermal kinetics were monitored by application of TGA-DTG-DTA. For Kinetic behavior of the investigated dyes during their degradation in an inert atmosphere, Kissinger, Ozawa, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) isoconversional (model-free) methods were applied. It was found that different thermal stabilities of investigated dyes are the consequence of their different chemical structures, including diverse substituents. Image 1 • TGA-DTG and DTA analysis of pyridone azo dyes were performed. • The thermal analysis has shown that dyes are stable up to 250 °C. • The degradation occurs mainly due to breaking of C N bond of hydrazone form. • The kinetic parameters indicated a change in the reaction pathways. • The investigated dyes are suitable for use in high-temperature processes. [ABSTRACT FROM AUTHOR]