Authors:V. Shevchenko, I. Nagayev, and N. Myasoyedov
This is a comparative study of different chromatographic techniques [gas-liquid (GLC), thin-layer (TLC), liquid (LC), high-pressure liquid (HPLC) chromatography] as applied to the analysis and preparative purification of tritium-labelled eicosanoids with a molar radioactivity of 1.8–8.8 TBq/mmol obtained by selective hydrogenation and by chemical or enzymic methods. We demonstrate the possibility of analyzing reaction mixtures and isolating individual multiply labelled eicosanoids with a chemical and radiochemical purity of 95–98%. Special features of HPLC for high molar radioactivity eicosanoids are considered.
Authors:Volodymyr M. Kozko, Andriy V. Bondarenko, Anatoliy V. Gavrylov, Olga S. Shevchenko, and Vitalii V. Gargin
Background and aims
One of the most severe manifestation displays of tuberculosis (TB) generalization is meningitis/meningoencephalitis. The purpose of this work was to improve the diagnostic efficiency of TB central nervous system (CNS) affection in human immunodeficiency virus (HIV)-infected persons.
Materials and methods
Meninges and cerebral tissues, taken from died patients, who were HIV-infected and dead from TB of CNS affection, were investigated histologically.
Results and discussion
Our examination showed that clinical course of the pathologic process loses the peculiarity of TB-undulating character, and changes in tissues have monomorphism that appears in the presence of the same type of granulomas with a few Pirogov–Langhans cells. Alterative reactions with formation of the large fields of caseous necrosis, necrotic focuses, areas of infiltration with polymorphic cellular elements went out on the first plan in the disorder of cerebrum in patients with the terminal stage of HIV infection. The tendency to decrease in inflammatory–proliferative processes was observed, which is confirmed by the presence of the poorly expressed cellular reaction on the peripheries of focuses of caseous necrosis.
Morphologic features of tuberculous meningoencephalitis in HIV-infected patients are the presence of edema, gliosis, trombovasculitis, small focal hemorrhage, tuberculous granuloma formation with a small number of Pirogov–Langhans cells, and the prevalence of alterative–exudative reactions.
Authors:R. Aliev, V. Bobrov, St. Kalmykov, M. Melgunov, I. Vlasova, V. Shevchenko, A. Novigatsky, and A. Lisitzin
Natural 210Pb and artificial 137Cs were applied for estimation of sedimentation rates for 14 cores collected in the White Sea, Franz Victoria and Novaya Zemlya
troughs. Vertical profiles of 137Cs with high resolution (0.5–1 cm) are presented for 18 cores. The agreement between sedimentation rates obtained from 210Pb age-dating and 137Cs vertical profiles was found. Two maxima of 137Cs specific activity were observed in the cores near the North Dvina and Onega mouths, which may be correspond to the Chernobyl
accident and global fallouts in early 1960-s.
Authors:A. Ponomarenko, C. Klason, N. Kazantseva, M. Buzin, M. Alexandre, Ph. Dubois, I. Tchmutin, V. Shevchenko, and R. Jérôme
Thermogravimetry was used to investigate the effects of different inorganic functional fillers on the heat resistance of polymer
matrices. The kinetic parameters of thermal oxidative degradation were shown to depend on the polymer, the chemical composition
of the filler surface, the filler concentration, and the processing method, which determines the distribution of filler particles
in the polymer matrix. Magnetic fillers (carbonyl iron, and hexaferrites of different structural types) were shown to be chemically
active fillers, increasing the heat resistance of siliconorganic polymers. Their stabilizing effect is due to blocking of
the end silanol groups and macroradicals by the surface of the filler and non-chain inhibition of thermal oxidative degradation.
In the case of fiber-forming polymers (UHMWPE, PVOH and PAN), most magnetic fillers are chemically inert, but at concentrations
of 30–50 vol% they increase the heat resistance of the composite. Addition of carbon black increased the heat resistance of
the thermoplastic matrix. The dependence of the thermal degradation onset temperature on the kaolin concentration in the polyolefin
matrix exhibited a maximum. Analysis of the experimental results demonstrated the operating temperature ranges for different
composites, and their maximum operating temperature.