The correlations of the enthalpy of vaporization and the surface tension of molecular liquids

Correlation relations based on Stefan's rule, which defined dependence between the enthalpy of vaporization, the surface tension, the molar volume and the molar mass of a substance, were obtained. For development of the correlation equations two computational procedures were used: a method of the least squares and a method of artificial neural networks. The method of artificial neural networks was shown to give somewhat better results than the linear least-squares procedure. The average deviation of the calculated values from the experimental ones did not exceed 6% for training set of substances and 10% for control set (the method of the least squares). For the method of artificial neural networks it is 3% and 8%, respectively.     

Regulating aspects of biosoluble and insoluble film release systems containing protein proteinase inhibitor

New types of potent aprotinin-containing medicinal polymer films are elaborated for topical applications. The higher the temperature of drying, the lower the steam absorption, the film swelling, and the velocity of aprotinin in vitro release. The presence of antimicrobials having the basic functional groups contributed to compacting the structure of the films and retention of aprotinin in them. The velocity of aprotinin release from the films is regulated by adding different polymers. Inclusion of polyvinylpirrolidone in the film resulted in acceleration and increase of aprotinin release. This was probably because of increasing the film swelling by a factor of 1.7. Additional retention of the inhibitor in films was achieved by inclusion of sodium alginate and cellulose powder capable of binding aprotinin. Soluble bioadhesive films derived from a copolymer of acrylamide,N-vinyl-pirrolidone, ethyl acrylate (M _r 30,000-600,000) and aprotinin were obtained and analyzed. Kinetics of aprotinin release from biosoluble films was studied under various conditions. The duration of aprotinin release was comparable with duration of gradual dissolution of the matrix. Bioavailability of aprotinin from soluble films was linear with time.     

Similarities and differences in the structure of 3<Emphasis Type="Italic">d</Emphasis>-metal monocarbides and monoxides

The structure and properties of the monocarbides ScC, TiC, VC, CrC, MnC, FeC, CoC, NiC, CuC, ZnC and their negatively and positively charged ions together with 3 d-metal monoxide cations are calculated by density functional theory (DFT) and hybrid DFT methods. In addition to the spectroscopic constants, the computed properties include the electron affinities, ionization energies, and dissociation energies. These results along with our previous results for the neutral and negatively charged 3 d-metal monoxides allow a detailed comparison of similarity and differences in the bonding of the metal oxides and carbides. These results are compared with results obtained using other theoretical approaches and with experiment. Chemical bonding, analyzed using the natural bond orbital scheme, was found to be rather different in the 3 d-metal monocarbides and monoxides.     

Sodium acetate catalyzed tandem Knoevenagel–Michael multicomponent reaction of aldehydes, 2-pyrazolin-5-ones,and cyano-functionalized C–H acids: Facile and efficient way to 3-(5-hydroxypyrazol-4-yl)-3-aryl-propionitriles

Sodium acetate catalyzed multicomponent reaction of aryl aldehydes, 2-pyrazolin-5-ones, and malononitrile or alkyl cyanoacetates in alcohols results in the formation of substituted 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles in 80–99% yields. The developed efficient catalytic approach to the substituted 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles – the promising compounds for human cardiovascular diseases therapy and different biomedical applications – is beneficial from the viewpoint of diversity-oriented large-scale processes and represents facile, efficient and environmentally benign synthetic concept for multicomponent reactions strategy.     

Controllable selective exfoliation of high-quality graphene nanosheets and nanodots by ionic liquid assisted grinding

Bulk quantities of graphene nanosheets and nanodots have been selectively fabricated by mechanical grinding exfoliation of natural graphite in a small quantity of ionic liquids. The resulting graphene sheets and dots are solvent free with low levels of naturally absorbed oxygen, inherited from the starting graphite. The sheets are only two to five layers thick. The graphene nanodots have diameters in the range of 9-29 nm and heights in the range of 1-16 nm, which can be controlled by changing the processing time.     

Suppression of intensity fluctuations in free space high-speed optical communication based on spectral encoding of a partially coherent beam

A new concept of a free space, high-speed (Gbps) optical communication system based on spectral encoding of radiation from a broadband pulsed laser is developed. It is shown that, in combination with the use of partially coherent laser beams and a relatively slow photosensor, scintillations can be suppressed by orders of magnitude for distances of more than 10 km.     

A New Model of Hemoglobin Oxygenation

The study of hemoglobin oxygenation, starting from the classical works of Hill, has laid the foundation for molecular biophysics. The cooperative nature of oxygen binding to hemoglobin has been variously described in different models. In the Adair model, which better fits the experimental data, the constants of oxygen binding at various stages differ. However, the physical meaning of the parameters in this model remains unclear. In this work, we applied Hill’s approach, extending its interpretation; we obtained a good agreement between the theory and the experiment. The equation in which the Hill coefficient is modulated by the Lorentz distribution for oxygen partial pressure approximates the experimental data better than not only the classical Hill equation, but also the Adair equation.     

Physicochemical properties, structure, and conformations of 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C4mim]NTf2 ionic liquid

Thermodynamic properties of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim]NTf2) ionic liquid have been studied by adiabatic calorimetry in the temperature range of 5 to 370 K. This compound has been found to form crystal, liquid, and glass. The temperature and enthalpy of fusion for [C(4)mim]NTf(2) have been determined to be T(fus) = 270.22 +/- 0.02 K and Delta(fus)H = 23.78 +/- 0.04 kJ.mol(-1), respectively. The heat capacity of crystalline [C(4)mim]NTf(2) in the T range of 205 to 255 K may vary by a few percent, subject to the procedure of the crystal preparation. The glass transition temperature for [C(4)mim]NTf(2) has been found to be T(g) = 181.5 +/- 0.1 K. On the basis of the results of DFT quantum chemical calculations, the experimental vibrational spectra, and the available literature data, thermodynamic properties of [C(4)mim]NTf(2) in the ideal-gas state have been calculated by the statistical thermodynamic methods. The entropy values for the gaseous compound obtained from the experimental data and the calculations are in satisfactory agreement.     

Ammonium iodide-mediated electrosynthesis of unsymmetrical thiosulfonates from arenesulfonohydrazides and thiols

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