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This paper is aimed to demonstrate an opportunity of the generation of wall-free non-stationary fire whirls under laboratory conditions without using mechanical swirling devices and estimation of their integral parameters. A simple experimental facility making possible the generation of concentrated fire vortex structures by means of combustion of solid fuel (urotropine) arranged symmetrically on a metallic underlying surface is described. With the use of photography, some data on the generation conditions and integral parameters (lifetime, height, and diameter) of fire whirls have been determined. [ABSTRACT FROM AUTHOR]

Novel ligands of the azine family for complexing with metals have been obtained as a result of the uncatalyzed C–C coupling reactions of quinoline, quinoxaline, 1,10-phenantroline, and their N -oxides with (1-oxido-3-phenyl-1,4-diazaspiro[4.5]deca-1,3-dien-2-yl)lithium. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effects of repeated i.p. injections of Cd, Pb or Cd+Pb in doses isoeffective in relation to LD50 were studied on rats. [•] Analysis of results with either ANOVA or the Theory of Experimental Design gave similar assessments of combined toxicity. [•] Thus paradigms of effect or dose additivity can be regarded as different ways of modelling the basically same phenomenon. [•] The type of combined toxicity depends on which effect is considered as well as on the dose levels and their ratio. [Copyright &y& Elsevier]

Abstract: The experimental results of the influence of different net structures on the dynamics of wall-free non-stationary air vortices are presented. These vortices were produced over underlying surface of aluminum sheet due to its controlled heating from below as a result of development of unstable stratification of air. It is strictly emphasized that on the contrary to previous studies no mechanical swirling devices and/or underlying surface rotation were used for the vortices generation. We have conducted the experiments on establishing how vertical nets placed in the travel line of a sufficiently non-stationary laboratory vortex affect its dynamics. Six different patterns of behavior of vortices in the interaction with net obstacles were revealed as a result of conducted experiments. We have distinguished several fundamental mechanisms of how nets affect a non-stationary vortex. Among these mechanisms is the action of small-scale turbulence generated behind the net with large-scale turbulence of the model vortex, leading to violation of its symmetry. The generalization is performed of the data obtained concerning the influence of net structures of various geometries on the laboratory-simulated vortices of different intensities. [Copyright &y& Elsevier]

Abstract: The purpose of the paper is to find the heating rates of underlying surface and air temporal and spatial temperature shear which lead to the stable genesis of wall-free non-stationary vortices. These vortices were generated over underlying surface of aluminum sheet due to its controlled heating from below as a result of development of unstable stratification of air. It is strictly emphasized that in contrary of previous studies no mechanical rotation devices and/or underlying surface rotation were used for the vortices generation. [Copyright &y& Elsevier]

Abstract: The molecular statics method is used to study the formation of defects and water incorporation in Y2O3. The crystal structure, the isothermal compressibility, and the formation enthalpy of Y2O3 calculated with the chosen interaction potentials are in good agreement with the experimental data. The formation energies of intrinsic and impurity defects are evaluated. The binding energy of protons and oxygen vacancies with an acceptor impurity at different distances is calculated. Various water incorporation reactions in the oxide are examined, including the mechanisms involving oxygen interstitial sites and oxygen vacancies produced by the acceptor doping. It is shown that the water incorporation in pure Y2O3 is energetically less favorable than in the acceptor doped oxide. [Copyright &y& Elsevier]

A series of novel push-pull fluorophores based on 2 H -imidazole scaffold bearing perfluorophenyl substituent and extended electron-donating conjugating π-system were synthesized. In particular, the Pd-catalyzed Suzuki-Miyaura coupling reactions were exploited as a main synthetic strategy to modify 4-(4-bromophenyl)-2,2-dimethyl-5-(pentafluorophenyl)-2 H -imidazole with various electron-donating functionalities. The comprehensive photophysical studies were carried out for the synthesized fluorophores, including the analysis of absorbance and emission spectra and determination of absolute quantum yields. The designed compounds were found to have a strong emission in the range of 470–610 nm depending on both the nature of solvent used and the structure of electron-donating group attached to the aryl moiety. The pH effect of the aqueous-organic mixture buffer solution on the fluorescent characteristics of the synthesized compounds was established and the deprotonation-induced "turn-on" pH sensing mechanism supported by DFT calculations was proposed for the first time. Particularly, the sequence of deprotonation was confirmed, and free energies for all N-protonated and N-proton-free forms were calculated. No toxic effect on the human embryonic kidney cells (HEK-293) at concentration of ≤512 μM was observed in vitro experiments. In addition, new opportunities for the practical application of these molecular ensembles were demonstrated in case of fluorometric determination of the pH both in model solutions and real saliva probes, with 3-(4-(2,2-dimethyl-5-(pentafluorophenyl)-2 H -imidazole-4-yl)phenyl)-9-phenyl-9 H -carbazole being used. [Display omitted] • Push-pull fluorophores with a strong emission in the range of 470–610 and quantum yields up to 96%. • No toxic effects at concentration of ≤512 μM from in vitro experiments. • Advanced "turn-on" fluorescent probes for determining the pH in saliva. [ABSTRACT FROM AUTHOR]

A series of novel water-soluble azaheterocyclic derivatives of nido -carborane bearing quinoxaline, 2 H -imidazole or 1,2,4-triazine moieties were first synthesized in 82–91% yields. The structures of these boron-enriched compounds were confirmed by the data of NMR, IR spectroscopy, and mass spectrometry. To access the toxicity level for these organoboron compounds, the cytotoxicity indexes (IC 50) were determined using by the MTT test on both human glioblastoma cell A-172 (IC 50 = 150–243 μM) and human embryonic lung cells (IC 50 = 424–944 μM) lines. The obtained preliminary results from in vitro analysis enable the synthesized water-soluble azaheterocyclic carboranes to be considered as challenging candidates in the design of agents for boron-neutron capture therapy (BNCT) of malignant tumors. [Display omitted] [ABSTRACT FROM AUTHOR]

A number of novel fluorinated derivatives of the family of pyrido[1,2- a indole fluorophores have first been synthesized via the aryne-mediated domino transformations of 5-(perfluorophenyl)-3-(pyridin-2-yl)-1,2,4-triazines. A comprehensive study of photophysical properties of the obtained polyfluoroaryl substituted derivatives, in which polyfluoroaryl, 1,2,3-triazole, and pyridoindole subunits contribute to a joint chromophore system, has shown that these compounds proved to exhibit a fluoresce with green light in acetonitrile solutions. Image 1 • Aryne-mediated transformations leading to novel pyrido[1,2- a indoles. • Polyfluorinated 10-(1 H -1,2,3-triazol-1-yl)pyrido[1,2- a indole fluorophores. • Novel green-emitting heteroaromatics with tunable photophysical characteristics. [ABSTRACT FROM AUTHOR]

A numerical method for solving elliptic differential equations (on unstructured computational grids) is described, which is based on a nonlinear compact-polynomial computational scheme. For this purpose, an approximate transition from the elliptic equation to the hyperbolic type of equations was carried out in the work. To find the solution of the hyperbolic version of the diffusion equation, a transition (in the vicinity of the computational cell Ω i) to a local curvilinear coordinate system was performed, a nonlinear compact-polynomial computational scheme was used (the "predictor" stage), and the control volume method was applied (the "corrector" stage). The results of initial testing (on problems of different physical nature) of the proposed numerical method are presented. [ABSTRACT FROM AUTHOR]

We investigated by the optical microscopy some cytological characteristics of the bronchoalveolar lavage fluid cell population 24 h after intratracheal instillation of microscale MnO 2 and BaCrO 4 particles (separately or together at two different doses) into the lungs of Wistar rats. Besides, the cytotoxicity of both particulates for rat peritoneal macrophages in vitro was assessed by the trypan blue exclusion test and proved significant. They were found to evoke a typical dose-dependent pulmonary phagocytosis response usually observed under inhalation or intratracheal impacts of low-soluble mineral and metal particles. A significant shift in the above mentioned cell population toward the prevalence of neutrophllic leukocytes (NL) over alveolar macrophages (AM) proved once more to be the most characteristic feature of this response. Although the particle load of a unit AM was always higher than that of a unit NL, the collective contribution of the recruited NLs to the total particles internalization by both AMs and NLs together was quite significant. This fact confirms that NL recruitment is an important auxiliary mechanism of the cytotoxic particle elimination from lungs compensating for the macrophage damage caused by them. Well adjusted functioning of this compensatory mechanism was additionally demonstrated by isobolographic analysis based on the Response Surface Methodology. On the other hand, this analysis confirmed that the type of combined toxicity depends on a particular effect this type is assessed for and on the effect’s dose-dependent level. [ABSTRACT FROM AUTHOR]

Comparative and combined damaging effects of NiO and Mn 3 O 4 nanoparticles were estimated on cultures of several established human cell lines. The cytotoxicity indices used were: (a) reduction in cellular dehydrogenase activity, (b) decrease in the ATP-content, (c) for SH-SY5Y cells also decrease in the tyrosine hydroxylase content. The combined cytotoxicity was modeled using the Response Surface Methodology. When assessing the stability of metal oxide nanoparticles (MeO-NPs) in cultural media used by us, we found that the addition of the fetal bovine serum (FBS) to them renders NiO-NPs and, to even greater extent, Mn 3 O 4 -NPs exponentially slow soluble while without FBS their dissolution was virtually undetectable. At the same time, sedimentation of these MeO-NPs noticeably slowed down in the presence of the same FBS. We have found dependence of cell damage on concentrations of MeO-NPs and higher cytotoxicity of Mn 3 O 4 -NP compared with NiO-NP. Thus, comparative assessment of the NPs unspecific toxicity obtained in our animal experiments was reproduced by the “ in vitro ” tests. However, with respect to manganese-specific brain damage “ in vivo ” discovered previously, present experiments on neurons “ in vitro ” showed only a certain enhancing effect of Mn 3 O 4 -NP on the action of NiO-NP, but the role of NiO-NP in the combination prevailed. [ABSTRACT FROM AUTHOR]

Sodium fluoride solution was injected i.p. to rats at a dose equivalent to 0.1 LD50 three times a week up to 18 injections. Two thirds of these rats and of the sham-injected ones were exposed to the whole body impact of a 25 mT static magnetic field for 2 or 4 h a day, 5 times a week. For mathematical analysis of the effects they produced in combination, we used a response surface model. This analysis demonstrated that (like in combined toxicity) the combined adverse action of a chemical plus a physical agent was characterized by a diversity of types depending not only on particular effects these types were assessed for but on their level as well. From this point of view, the indices for which at least one statistically significant effect was observed could be classified as identifying (1) single-factor action; (2) additivity; (3) synergism; (4) antagonism (both subadditive unidirectional action and all variants of contradirectional action). Although the classes (2) and (3) taken together encompass a smaller part of the indices, the biological importance of some of them renders the combination of agents studied as posing a higher health risk than that associated with each them acting alone. [ABSTRACT FROM AUTHOR]

Stable suspensions of NiO and/or Mn 3 O 4 nanoparticles with a mean diameter of 16.7 ± 8.2 nm and 18.4 ± 5.4 nm, respectively, prepared by laser ablation of 99.99% pure metals in de-ionized water were repeatedly injected IP to rats at a dose of 0.50 mg or 0.25 mg 3 times a week up to 18 injections, either separately or in different combinations. Many functional indices as well as histological features of the liver, spleen, kidneys and brain were evaluated for signs of toxicity. The accumulation of Ni and Mn in these organs was measured with the help of AES and EPR methods. Both metallic nanoparticles proved adversely bio-active, but those of Mn 3 O 4 were found to be more noxious in most of the non-specific toxicity manifestations. Moreover, they induced a more marked damaging effect in the neurons of the caudate nucleus and hippocampus which may be considered an experimental correlate of manganese-induced parkinsonism. Mathematical analysis based on the Response Surface Methodology (RSM) revealed a diversity of combined toxicity types depending not only on particular effects these types are assessed for but on their level as well. The prognostic power of the RSM model proved satisfactory. [ABSTRACT FROM AUTHOR]

For characterizing the three-factorial toxicity, we proposed a new health risk-oriented approach, the gist of which is a classification of effects depending on whether a binary combined toxicity’s type remains virtually the same or appears to be either more or less adverse when modeled against the background of a third toxic. To explore possibilities of this approach, we used results of an experiment in which rats had been injected ip 3 times a week (up to 20 injections) with a water solution of either one of the toxics (Mn, Ni or Cr-VI salts) in a dose equivalent to 0.05 LD50, or any two of them, or all the three in the same doses, the controls receiving injections of the same volume of distilled water (4 mL per rat). Judging by more than 30 indices for the organism's status, all exposures caused subchronic intoxication of mild to moderate strength. For each two-factorial exposure, we found by mathematical modeling based on the isobolograms that the binary combined subchronic toxicity either was of additive type or departed from it (predominantly toward subadditivity) depending on the effect assessed, dose, and effect level. For the three-factorial combination, different classes of effects were observed rather consistently: class A – those regarding which the third toxic’s addition made the binary toxicity type more unfavorable for the organism, class B – those regarding which the result was opposite, and class C – those regarding which the type of binary combined toxicity on the background of a third toxic virtually remained the same as in its absence. We found a complicated reciprocal influence of combined metals on their retention in kidneys, liver, spleen and brain which might presumably be one of the possible mechanisms of combined toxicity, but the lack of an explicit correspondence between the above influence and the influence on toxicity effects suggests that this mechanism is not always the most important one. The relevance of the proposed classification to health risk analysis and management is briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract: Solid heterospin compounds based on Cu(hfac)2 complexes with a new group of nitronyl nitroxides bearing different azine-N-oxide substituents at position 2 of the 2-imidazoline ring (L n ) were studied. The major factor responsible for the change in the magnetic characteristics of the [Cu(hfac)2L1] complex with triazine nitronyl nitroxide with temperature was shown to be the specific pairwise packing of heterospin molecules with the dominant antiferromagnetic exchange between the radical fragments of adjacent molecules. For complexes of Cu(hfac)2 with 1-oxoazin-2-yl-substituted nitronyl nitroxides L2 and L4, 7-membered metallocycles were obtained, although they form rarely. It was shown that polymer chains formed in the solid complex with spin-labeled pyrazine-N-oxide [(Cu(hfac)2)3(L3)2] due to the cross-linking of {(Cu(hfac)2)2(L3)2} binuclear fragments via the bridging [Cu(hfac)2]. [Copyright &y& Elsevier]

Abstract: Results of experimental and numerical simulations of the downward turbulent gas flow laden with dispersed solid particles in a vertical pipe are presented. The influence of the particles on the turbulence was studied at moderate particle concentrations. The radial profiles of the axial and radial velocity components and of the turbulent kinetic energy of the carrier (gas) and the dispersed phases (50μm spherical glass particles) were measured using two-component laser Doppler anemometer (LDA). Calculations were performed at both experimental and superset conditions with various size and material of particles. The mathematical formulation employs a set of equations in Euler variables for description of the transport processes in the fluid and disperse phases. The addition of particles into a turbulent carrier flow decreases the level of turbulence of the gas phase because of particles involvement into fluctuation motion. A significant anisotropy of fluctuations of the particle velocity is found. The amplitude of turbulent fluctuations of particle velocity in the axial direction is much higher than that in the radial direction. [Copyright &y& Elsevier]

[Display omitted] • A 1,3/1,4-diazine's modified SPE for NB determination in honey was prepared. • Cathodic currents of NB reduction enhanced the diazine-modified SPEs. • The best NB response was obtained by using co-polymerization of the receptor layer. • The low detection limit 0.107 μM allows NB in honey samples to be detected. • The analysis of spiked probes showed the high precision of the sensor with HPLC. In this work, a screen-printed electrode (SPE) modified by 1,3/1,4-diazines was prepared for the rapid and sensitive determination of nitrobenzene (NB). The obtained results indicated enhanced cathodic currents of direct NB reduction into hydroxylaminophenol on the diazine-modified SPEs. The enhanced effect was most likely due to the combination of complexation and collisional processes of diazines towards nitroaromatic compounds and also the diazine-modified electrodes' increased electroconductivity. The best electrochemical responses were obtained in square wave voltammetry mode by using the carbazolyl substituted diazines as a component of the sensitive layer, which was assembled by co-electropolymerization with the unsubstituted carbazole on the electrode during 5 cycles. The low detection limit estimated as 0.107 μM and wide linear range (1–1000 µM) enables NB in water and food samples to be determined. The developed modified electrode was applied in the analysis of commercial honey samples. [ABSTRACT FROM AUTHOR]