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The 65thBirthday of Professor Roman Leboda

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Gun'ko V., Turov V., Skubiszewska-Zięba J.

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2009

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vol. 64

vii-ix

2

Interfacial behavior of water bound to nitrocellulose containing residual nitric and sulfuric acids

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Gun’ko V., Tomaszewski W., Krupska T., Turov K., Leboda R., Turov V.

Open Chemistry

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2014

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vol. 12

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issue 4

509-518

EN

To prepare nitrocellulose (NC), microcrystalline cellulose was treated in a mixture of nitric and sulfuric acids. Prepared NC containing a small amount of acids was studied at a different hydration degree (h = 10–1000 mg g−1) in different dispersion media (chloroform-d, acetone-d6 or their mixtures) using low-temperature 1H NMR spectroscopy. The hydration degree and the presence of residual acids affected the temperature dependence of the chemical shifts of proton resonance of water bound to NC. The Gibbs free energy of bound water became less negative with increasing hydration rate. The chloroform and acetone media affect the behavior of bound-to-NC water unfrozen at T<273 K differently. Quantum chemical calculations were performed using ab initio (HF/6-31G(d,p)), DFT (B3LYP/6-31G(d,p)) and semiempirical PM7 methods to analyze the interfacial behavior of water interacting with NC containing residual amounts of nitric and sulfuric acids.

3

Water structure in fungi Amanita musscaria and their composite system with hydrocompacted nanosilica A-300

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Krupskaya Т., Jovaišas P., Bieliauskienė R., Yelahina N., Charmas B., Turov V.

Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia

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2017

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vol. 72

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issue 2

EN

The state of water in the fruit body of the Amanita muscaria mushroom and its composite with “wetting-drying”nanosilica A-300 was studied by low-temperature 1H NMR spectroscopy. It was found that even in the initial biomaterial, part of the water is in a weakly associated state. After drying, the portion of weakly bound water decreases, but in the medium of CDCl3, almost all water becomes weakly boned. This effect is accompanied by a threefold increase (from 3.4 to 10.3 J/g) of the total binding energy of water, which, is probably due to the transition of water from the system of spherical (cylindrical) clusters to a two-dimensional film, uniformly distributed over the surface of the biomaterial. It is suggested that due to the binding by the surface of the silica from the composite, the toxic substances present in the mushroom in the form of complexes with enzymes, will not be desorbed.

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Interaction of fibrinogen with nanosilica

76%

Rugal A., Gun’ko V., Barvinchenko V., Turov V., Semeshkina T., Zarko V.

Open Chemistry

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2007

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vol. 5

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issue 1

32-54

EN

Interaction of human plasma fibrinogen (HPF) with fumed nanosilica A-300 in a phosphate buffer solution (PBS) was studied using 1H NMR spectroscopy with layer-by-layer freezing-out of bulk and interfacial water in the temperature range of 210–273 K, TSDC (90 T FTIR, and UV spectroscopy methods. An increase in concentration of HPF in the PBS leads to a decrease in amounts of structured water (frozen at T FTIR and UV spectra show that the HPF adsorption on silica leads to structural changes of the protein molecules. These changes and formation of hybrid HPF/A-300 aggregates can increase the rate of clotting that is of importance on nanosilica application as a component of tourniquet preparations. [...]

5

Behaviour of pure water and water mixture with benzene or chloroform adsorbed onto ordered mesoporous silicas

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Gun’ko V., Turov V., Turov A., Zarko V., Gerda V., Yanishpolskii V., Berezovska I., Tertykh V.

Open Chemistry

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2007

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vol. 5

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issue 2

420-454

EN

Structural characteristics of synthesized ordered mesoporous silicas MCM-41, MCM-48 and SBA-15 were studied using XRD, nitrogen adsorption and FTIR methods. Pure water and mixtures with water/benzene and water/chloroform-d adsorbed onto silicas were studied by 1H NMR spectroscopy with layer-by-layer freezing-out of bulk and interfacial liquids. Concentrated aqueous suspensions of MCM-48 and SBA-15 were studied by thermally stimulated depolarization current (TSDC) method. Benzene and chloroform-d can displace a portion of water to broad pores from the pore walls and from narrower pores, especially in the case of a large excess of an organic solvent. This process is accompanied by diminution of both interaction energy of water with an adsorbent surface and freezing temperature depression of adsorbed water. The effect of nonpolar benzene on pore water is much stronger than that of weakly polar chloroform-d. Modifications of the Gibbs-Thomson relation to describe the freezing point depression of mixtures of immiscible liquids confined in pores allow us to determine distribution functions of sizes of structures with unfrozen pore water and benzene. [...]

6

Interaction of unmodified and partially silylated nanosilica with red blood cells

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Gun’ko V., Galagan N., Grytsenko I., Zarko V., Oranska O., Osaulenko V., Bogatyrev V., Turov V.

Open Chemistry

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2007

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vol. 5

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issue 4

951-969

EN

Interaction of red blood cells (RBCs) with unmodified and partially (50%) silylated fumed silica A-300 (nanosilica)was studied by microscopic, XRD and thermally stimulated depolarisation current (TSDC) methods. Nanosilica at a low concentration C A-300C A-300 = 1 wt% all RBCs transform into shadow corpuscles because of 100% haemolysis. Partial (one-half) hydrophobization of nanosilica leads to reduction of the haemolytic effect in comparison with unmodified silica at the same concentrations. A certain portion of the TSDC spectra of the buffered suspensions with RBC/A-300 is independent of the amounts of silica. However, significant portions of the low-and high-temperature TSDC bands have a lower intensity at C A-300 = 1 wt% than that for RBCs alone or RBC/A-300 at C A-300 = 0.01 wt.% because of structural changes in RBCs. Results of microscopic and XRD investigations and calculations using the TSDC-and NMR-cryoporometry suggest that the intracellular structures in RBCs (both organic and aqueous components) depend on nanosilica concentration in the suspension. [...]

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The 65thBirthday of Professor Roman Leboda

Interfacial behavior of water bound to nitrocellulose containing residual nitric and sulfuric acids

Water structure in fungi Amanita musscaria and their composite system with hydrocompacted nanosilica A-300

Interaction of fibrinogen with nanosilica

Behaviour of pure water and water mixture with benzene or chloroform adsorbed onto ordered mesoporous silicas

Interaction of unmodified and partially silylated nanosilica with red blood cells