Исследован вклад карбонильных соединений в образование атмосферного органического аэрозоля в присутствии типичных загрязнителей городской атмосферы. Альдегиды и кетоны, поступающие в атмосферу из природных и антропогенных источников, идентифицированы методом высокоэффективной жидкостной хроматографии. Натурные измерения проведены на территории Новосибирского научного центра и в прилегающих лесных массивах. Обнаружено, что при переносе типичных газообразных загрязнителей городского воздуха (оксиды азота, озон) в воздух лесных массивов, а биогенных соединений (алкенов, альдегидов) на территорию города резко меняются кинетика и механизм образования органического аэрозоля по сравнению с процессами в типичной городской атмосфере. Так, в присутствии озона выход аэрозольных продуктов фотонуклеации формальдегида, ацетальдегида и пропаналя увеличивается в 4–8 раз, а бензальдегида и акролеина уменьшается в 5 и 30 раз соответственно, тогда как для ароматических замещенных альдегидов и фурфураля выход аэрозоля увеличивается незначительно (до 30%). Полученные результаты позволяют проводить количественные оценки мощности природных и антропогенных источников органического аэрозоля в условиях лесостепной зоны Западной Сибири и прогнозировать биологическое действие образующегося аэрозоля при разных сочетаниях выбросов. Contribution of carbonyl compounds into the generation of atmospheric organic aerosol in the presence of typical urban air pollutants is investigated. Aldehydes and ketones entering the atmosphere from natural and anthropogenic sources are identified by means of high-performance liquid chromatography. Field measurements were carried out on the territory of Novosibirsk scientific center and in adjacent forest areas. It is shown that the transport of typical gaseous urban air pollutants (nitrogen oxides and ozone) into the air of forest areas and the transport of biogenic compounds (alkenes and aldehydes) to the urban territory cause sharp changes of the kinetics and mechanism of organic aerosol generation in comparison with the processes taking place in typical urban atmosphere. Thus, in the presence of ozone, the yield of aerosol products from formaldehyde, acetaldehyde, and propanal photonucleation increases by a factor of 4–8, while for benzaldehyde and acrolein it exhibits 5- and 30-fold decrease, respectively. For aromatic substituted aldehydes and furfural, aerosol yield slightly increases (only up to 30 %). The results make it possible to carry out quantitative evaluation of the capacity of natural and anthropogenic sources of organic aerosol in the forest-steppe zone of Western Siberia and predict the biological effect of aerosol generated in the presence of various pollutants.

The effect of terahertz radiation on clusterization of bovine serum albumin (BSA) molecules and on BSA binding with nickel, cobalt and cadmium ions is investigated by means of high performance liquid chromatography and EPR spectroscopy under variation of the concentration of molecular oxygen in solution. Irradiation is detected to remove steric hindrance for oxygen adsorption. The degree of nickel and cobalt ion binding with irradiated BSA samples is substantially higher than with non-irradiated ones, while for cadmium the binding degree is the same and rather low in both cases. The functional groups in BSA molecule participating in metal ion binding are revealed by means of semi-empirical simulation.

The possibility of adapting a chemical system for generating nitric oxide (NO) and superoxide anion (O2•−) upon the decomposition of 3-morpholinosydnonimine (SIN-1) in a buffer solution to the conditions of a similar experiment on bacterial cultures in the field of an MRI scanner was examined. For this system, the magnetic field effect on the recombination of the two radicals to form peroxynitrite (ONOO−) in a range of strong magnetic fields was experimentally found earlier and explained by the Δg mechanism. The transition from a model in vitro system involving biologically relevant species NO, O2•−, and ONOO− to an in vivo system and the development of a reliable model system with a reproducible magnetic field effect that can be employed as a working tool in further studies were considered. The decomposition of SIN-1 in the presence of components of an LB culture medium for bacterial cultures and the redox activity of the medium itself and a possible autoinitiation of the Fenton reaction on the intrinsic iron content were studied by spectrophotometry and ESR spectroscopy of spin traps. A decrease in the viability and formation of filaments for the E.coli JM109 strain were observed in experiments on the exposition of the bacterial strains in the presence of radical donors in a strong magnetic field of 11.7 T.

Isolation of luminophores from the mycelium of a luminous fungus Neonothopanus nambi is reported. In addition to the emission peak with a maximum at 520–530 nm (the wavelength of visible green light) that corresponded to the maximum of light emission by the fungus in vivo, the fluorescence spectra of the raw extracts contained a peak with a maximum in the visible blue-light range. The luminophore that emitted the blue light was an individual compound with a molecular weight of 894 Da. Calculations that took the isotope composition of chemical elements into account pointed at C52H65N2O11, C51H65N4O10, C53H61N6O7, C47H65N4O13, and C46H65N6O12 as the putative chemical formulae of the luminophore. A sample that contained substances of a yellow color was obtained; these substances emitted fluorescence at the wavelengths of green visible light. The luminophores in this sample probably included riboflavin or derivatives thereof (flavin mononucleotide or flavin adenine dinucleotide).

The surface functional groups of organic nanoparticles formed in furfural photonucleation were identified with the help of rupture event scanning. The presence of carboxylic groups on the surface of the particles was discovered. The photonucleation kinetics was studied in a laboratory photochemical reactor using a diffusion-based aerosol spectrometer. It was demonstrated that photonucleation involves photochemically generated short-lived free radicals, detected and identified by means of spin trapping. The photonucleation mechanism is proposed.

The luminescent system of higher luminous fungi is not fully understood and the enzyme/substrate pair of the light emission reaction has not been isolated. It was suggested that luminescence of fungi involves oxidase-type enzymes, and reactive oxygen species are important for fungal light production. Generation of reactive oxygen species can be stimulated by ionizing irradiation, which has not been studied for luminous fungi. We report the effect of X-irradiation on the luminescence of fungus Neonothopanus nambi. Experiments were performed with mycelium on a home-built setup based on an X-ray tube and monochromator/photomultiplier tube. Application of X-rays does not change the emission spectrum, but after approximately 20 min of continuous irradiation, light production from unsupported mycelium starts growing and increases up to approximately five times. After peaking, its level decreases irrespective of the presence of X-irradiation. After staying at a certain level, light production collapses to zero, which is not related to the drying of the mycelium or thermal impact of radiation. The observed shape of kinetics is characteristic of a multistage and/or chain reaction. The time profile of light production must reflect the current levels of radicals present in the system and/or the activity of enzyme complexes involved in light production.

Deferiprone (L1) is an effective iron-chelating drug that is widely used for the treatment of iron-overload diseases. It is known that in aqueous solutions Fe2+ and Fe3+ ions can produce hydroxyl radicals via Fenton and photo-Fenton reactions. Although previous studies with Fe2+ have reported ferroxidase activity by L1 followed by the formation of Fe3+ chelate complexes and potential inhibition of Fenton reaction, no detailed data are available on the molecular antioxidant mechanisms involved. Similarly, in vitro studies have also shown that L1–Fe3+ complexes exhibit intense absorption bands up to 800 nm and might be potential sources of phototoxicity. In this study we have applied an EPR spin trapping technique to answer two questions: (1) does L1 inhibit the Fenton reaction catalyzed by Fe2+ and Fe3+ ions and (2) does UV–Vis irradiation of the L1–Fe3+ complex result in the formation of reactive oxygen species. PBN and TMIO spin traps were used for detection of oxygen free radicals, and TEMP was used to trap singlet oxygen if it was formed via energy transfer from L1 in the triplet excited state. It was demonstrated that irradiation of Fe3+ aqua complexes by UV and visible light in the presence of spin traps results in the appearance of an EPR signal of the OH spin adduct (TMIO–OH, a(N)=14.15 G, a(H)=16.25 G; PBN–OH, a(N)=16.0 G, a(H)=2.7 G). The presence of L1 completely inhibited the OH radical production. The mechanism of OH spin adduct formation was confirmed by the detection of methyl radicals in the presence of dimethyl sulfoxide. No formation of singlet oxygen was detected under irradiation of L1 or its iron complexes. Furthermore, the interaction of L1 with Fe2+ ions completely inhibited hydroxyl radical production in the presence of hydrogen peroxide. These findings confirm an antioxidant targeting potential of L1 in diseases related to oxidative damage.

This contribution reports the design and synthesis of a series of spin-labeled charge acceptors to produce three-spin systems of "radical ion/biradical ion" type in X-irradiated alkane liquids. This opens the way to study spin triads in experimental conditions, in which short-lived radical ion pairs are conventionally studied, thus offering optically detected techniques such as magneto-resonance OD ESR and level-crossing MARY spectroscopy. The structure of the synthesized 2-imidazoline-1-oxyl derivatives is A-Sp-R, where A is a positive or negative charge acceptor, R is a stable radical, and Sp is a hydrocarbon bridge. The set of 20+ compounds represent a convenient tool to construct experimental three-spin systems with various properties, e.g. with the "third" spin introduced into one or the other partner of the radical ion pair. The degree of exchange coupling between the two paramagnetic fragments in the biradical ion has been demonstrated to strongly depend on the type of the radical fragment R and the structure of the bridge Sp. As a result, a series of acceptors with systematically reduced exchange interaction has been synthesized, and optimal systems for the observation of low magnetic field effect have been found. In the most favorable case, an OD ESR signal from a spin triad living as short as ca. 100 ns has been registered as a single unresolved line. The exchange integral for this biradical anion (9) was estimated from OD ESR and ESR experiments to be ca. 10(3) G by the order of magnitude, which is much greater than the hyperfine couplings in the biradical ion but much smaller than the thermal energy kT.

Radical cations derived from saturated hydrocarbons are highly reactive oxidizing species, and the rates of their bimolecular reactions are often determined by the frequency of diffusion collisions in solution. It is known that reactions of primary radical cations (holes) arising in cyclohexane, methylcyclohexane, and cis and trans -decalins on exposure to ionizing radiation can be 10 to 100 times faster than molecular diffusioncontrolled reactions [1, 2]. Investigations have shown that the high reaction rates in these cycloalkanes are due to the very high mobility of the primary holes of the solvent, which is caused by degenerate electron transfer between the radical cation and surrounding solvent molecules. No highly mobile holes have been observed in other cycloalkanes or in normal and branched alkanes [1, 2]. In this study, the methods of time-resolved magnetic field [3, 5] and electric field [4] effects in recombination fluorescence of geminate radical-ion pairs, developed in our previous works, were used to detect highly mobile solvent holes. Owing to the high time resolution ( ~1 ns), these methods provide the detection of highly mobile holes having shorter lifetimes than those detectable by the techniques used previously. For the formation mechanism of the magnetic field effect, it is significant that ionizing irradiation of alkane solutions produces geminate radical-ion pairs mainly in the singlet spin state. The singlet‐triplet transitions in the pairs induced by hyperfine coupling (HFC) and the differences in the radical g -factors or paramagnetic relaxation modulate the yields of the singlet-excited molecules resulting from recombination of radical ions. The time variation of the recombination fluorescence I ( t ) of the irradiated solutions can be written as follows:

Quantum beats caused by the hyperfine coupling (hfc) with magnetically equivalent protons were observed in the recombination fluorescence of the singlet-correlated pairs of secondary radical ions generated in cyclohexane solutions by ionizing radiation. In agreement with theoretical predictions, the ratio IH(t)/I0(t) of fluorescence decay kinetics in high and zero magnetic fields showed narrow peaks for the radical cations with an even number of the equivalent protons. To generate radical pairs, p-terphenyl-d14 was used as an electron acceptor while the solvent holes were trapped by octamethyl-1,4-cyclohexadiene, tetramethylethylene, 9,10-octalin, cis-decalin, hexamethylbenzene, durene, p-diethylbenzene, p-xylene, or benzene. When diisopropylamine was used as a hole acceptor, a trough was observed instead of the strongest peak. The position of the strongest peak (trough) is determined by the value of hfc constant only and is independent of the number of protons.