Multivalued penalty method for evolution variational inequalities with <Emphasis Type="Italic">λ</Emphasis><Subscript>0</Subscript>-pseudomonotone multivalued maps

We consider evolution variational inequalities with λ ₀-pseudomonotone maps. The main properties of these maps are investigated. By using the finite-difference method, we prove the property of strong solvability for the class of evolution variational inequalities with λ ₀-pseudomonotone maps. Using the penalty method for multivalued maps, we show the existence of weak solutions of evolution variational inequalities on closed convex sets. The class of multivalued penalty operators is constructed. We also consider a model example to illustrate this theory.     

Low-temperature oxidation of sulfur dioxide by molecular oxygen in aqueous solutions of non-transition metals trifluoroacetates

Oxidation of SO₂ was shown to occur in aqueous solutions of Li, Na, and K trifluoroacetates at room temperature. Oxidative activity of the non-transition metal trifluoroacetates increases on decreasing pH of solution and at equal pH values, it follows the sequence: Li < Na < K.     

Production of Gold nanoparticles in aqueous solutions of cellulose derivatives

It is shown that gold nanoparticles can be produced using cellulose ethers, methylhydroxyethyl cellulose, and carboxymethyl cellulose as reducing agents that also play the role of nanoparticle stabilizers. Depending on the synthesis conditions, nanoparticle sizes vary in the range of 20–100 nm. The application of carboxymethyl cellulose as a stabilizer may give rise to the formation of a bimodal ensemble of nanoparticles with sizes of 4–5 and 30–40 nm. The differences in the mechanisms for the reduction and stabilization of gold nanoparticles in the presence of these cellulose derivatives are established by IR spectroscopy. The obtained colloidal dispersions of gold nanoparticles remain stable for a long time.     

tert-Butylthiacalix[4]arene monolayers as a biomimetic model for the oxidation of antioxidants with cytochrome c

The possibility of designing a model of sensor to antioxidants based on thiacalix[4]arene monolayers with immobilized cytochrome c was shown. The molecular surface area S ₀ of thiacalix[4]arene in the monolayers and the surface pressure coefficient ?dπ/dS (elasticity) reflect changes in the redox state of cytochrome c in the presence of dihydroquercetin and ascorbic acid in the aqueous subphase. The absorption spectra in the visible and UV ranges of solutions of the subphase and transferred thiacalix[4]arene monolayers with immobilized cytochrome c confirm the oxidation of the antioxidants to quinones and formation of the reduced form of cytochrome c.     

Deep purification of hexamethyldisilazane

We considered a deep cleaning of 1,1,1,3,3,3-hexamethyldisilazane used in microelectronics and organoelement synthesis from a series of homogeneous and heterogeneous admixtures by various physicochemical methods.     

Vectorized ferrocenes with estrogens and vitamin D2: synthesis, cytotoxic activity and docking studies

Three ferrocene complexes vectorized with estrogens and vitamin D(2) were synthesized and fully characterized by spectroscopic, electrochemical and computational methods. The synthesis of these esters was accomplished by reacting ferrocenoyl chloride with the corresponding ROH groups (R = ergocalciferol, estradiol, estrone). The cytotoxicity of these complexes in HT-29 colon cancer and MCF-7 breast cancer cell lines was investigated in vitro. Only ferrocenoyl 17β-hydroxy-estra-1,3,5(10)-trien-3-olate showed good cytotoxic activity in both cell lines, exceeding those of ferrocenium and ferrocene. In MCF-7, ferrocenoyl 17β-hydroxy-estra-1,3,5(10)-trien-3-olate exhibited remarkable IC(50), in the low micromolar range. This may be attributed to the presence of the estradiol vector. Docking studies between alpha-estrogen receptor ligand binding site and ferrocenoyl 17β-hydroxy-estra-1,3,5(10)-trien-3-olate revealed some key hydrophobic interactions that might explain the cytotoxic activity of this ester.     

In vivo noninvasive detection of chlorophyll distribution in cucumber (Cucumis sativus) leaves by indices based on hyperspectral imaging

The objective of this study was to investigate the spectral behavior of the relationship between reflectance and chlorophyll content and to develop a technique for non-destructive chlorophyll estimation and distribution in leaves using hyperspectral imaging. The hyperspectral imaging data cube of cucumber (Cucumis sativus) leaves in the range of 450-850 nm was investigated and preprocessed. Sixty optical signatures or indices as a function of the associated reflectance (R(λ)) at the special wavelength (λ) nm which proposed in the literatures were used to predict the total chlorophyll content in cucumber leaves. Finally, R(710)/R(760), (R(780)-R(710))/(R(780)-R(680)), (R(750)-R(705))/(R(750)+R(705)), (R(680)-R(430))/(R(680)+R(430)), R(860)/(R(550)×R(708)), (R(695-705))(-1)-(R(750-800))(-1), and REP-LEM (a index based on red edge position and estimated with a linear extrapolation method) were identified as optimum indices. Red-edge waveband (680-780 nm) appeared in all these optimum indices, indicating the importance of REP (red edge position) in chlorophyll estimation. When (R(695-705))(-1)-(R(750-800))(-1), the best index was applied to an independent validation set, chlorophyll content (r=0.8286) were reasonably well predicted, indicating model robustness. Depending on the sample, this technique enables to identify and characterize the relative content of various chlorophyll that distribution in the cucumber leaves. The map shows a relatively low level of chlorophyll at margins. Higher level can be noticed in the regions along the main veins and in some areas exhibiting dark green tissue. Our results indicate that hyperspectral imaging has considerable promise for predicting pigments in leaves and, the pigments can be detected in situ in living plant samples non-destructively.     

A comparison between the radicals formed by radiation in barbituric acid and its 2-thio derivative

The radicals formed by radiation in 2-thiobarbituric acid single crystals have been studied by E.S.R. spectroscopy. The main radical is formed by abstraction of one of the protons bonded to C₅. The electronic structure of this radical has been compared to that of the related radical formed in ordinary barbituric acid. Both the experimental data as well as the MO calculations show that when oxygen is substituted by sulphur the isotropic proton splitting is reduced and the g-value anisotropy increased. This is explained by a transfer of unpaired spin density from C₅ to the sulphur atom.     

A braking drift current on the slopes of wind waves in an amplification zone

A drift current was experimentally studied on the slopes of wind waves in an amplification zone. It was found that the drift decreases proportionally to the wave steepness at the front wave slope. We tested a hypothesis that relates the decrease in the drift velocity at the front wave slope with the formation of vortices in a viscous air layer. A physical model of the event and a method for the calculation of the drift decrease at the front wave slope in an amplification zone are suggested. The model calculations agree well with experimental data within the measurement error, which is less than 10% of the measured value.     

Level manifolds of linear integrals in mechanical systems

Let a mechanical system admit a complete system of invariant velocity-independent relations (i.e., first integrals or differential constraints); one of these relations is quadratic, whereas the others are linear in velocities. If the configuration space is compact and orientable, then the joint level of the invariant relations has two connected components diffeomorphic to this level. If the configuration space is not orientable, then the joint level is connected and diffeomorphic to an orientable manifold. Several examples are given.