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Supercapacity of Soft-Expanded Graphite in Li-Intercalational Electric Current Generation

100%

Shvets R., Grygorchak I., Kurepa A., Pokladok N., Sementsov Y., Dovbeshko G., Sheregii Y., Seredyuk B.

Acta Physica Polonica A

2015

vol. 128

issue 2

208-209

A microwave-intercalation modification of natural graphite which ensures its effective use as a cathode material of Li-based sources of electric current is developed. Interconnection between the parameters of modification and thermodynamic and kinetic behavior of Li-intercalation electric current generation is established. On the basis of the obtained data from impedance spectroscopy, X-ray diffractometry analysis, and spectroscopy of the Raman scattering of light, the mechanism of the observed phenomena is suggested.

Dielectric Relaxation in Hydrogen Bonded Urea-Based Supramolecular Polymer N,N'-di(2,2-dipentylheptyl)urea

80%

Jadżyn J., Bouteiller L., Déjardin J., Czechowski G.

Results of the dielectric relaxation studies, performed for supramolecular polymer formed by N,N'-di(2,2-dipentylheptyl)urea dissolved in carbon tetrachloride, are presented. The measurements were done for N,N'-di(2,2-dipentylheptyl)urea concentration up to about 7% (in mole fraction) in the frequency region from 100 kHz to 100 MHz and at the temperatures from 5ºC to 50ºC. The analysis of the experimental data were performed with the Havriliak-Negami equation. In the studied range of N,N'-di(2,2-dipentylheptyl)urea concentration and temperature, the obtained values of exponentsα andβ of the Havriliak-Negami equation are equal to 0.9±0.1 and 0.7±0.1, respectively, showing an anomaly in the dielectric relaxation behavior close to the Davidson-Cole type. Two examples of the modeling of dielectric properties of the supramolecular polymer solutions were presented.

Biophysical changes induced by cholesterol on phosphatidylcholine artificial biomembranes containing alamethicin oligomers

51%

Cernescu A., Luchian T.

Open Physics

2006

vol. 4

issue 2

155-167

Cholesterol is an important constituent of eukaryotic cell membranes, whose interaction with phospholipids leads to a broad range of biological roles, such as: maintenance of proper fluidity, formation of raft domains, reduction of passive permeability of various chemical species through the bilayer (e.g., glucose, glycerol, K+, Na+ and Cl− ions), and increased mechanical strength of the membrane. In this work we studied an interesting paradigm, as to whether cholesterol-containing phosphatidylcholine biomembranes influence the kinetics and transport features of alamethicin oligomers embedded into it. We demonstrate that moderate relative amounts of cholesterol increase the electrical conductance of various sub-conductance states of the alamethicin oligomer, caused probably by a non-monotonic change in the lumped dipole moment of the biomembrane. Our data suggest that biomembrane stiffness caused by cholesterol, visibly modifies the association-dissociation rates of alamethicin oligomerization in the biomembrane. Moreover, increasing concentrations of cholesterol seem to lead to more stable intermediate alamethicin oligomers. We show that in the presence of cholesterol, as the diameter of the alamethicin oligomer increases, so does the time of another monomer to get picked up. These results brings into focus the interesting issue of how oligomerization of proteins affects their interaction affinities for membrane-based lipids.

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2 Acta Physica Polonica A

1 Open Physics

1 2015

2 2006

1 Bouteiller L.

1 Cernescu A.

1 Czechowski G.

1 Dovbeshko G.

1 Déjardin J.

1 Grygorchak I.

1 Jadżyn J.

1 Kurepa A.

1 Luchian T.

1 Pokladok N.

1 Sementsov Y.

1 Seredyuk B.

1 Sheregii Y.

1 Shvets R.

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Supercapacity of Soft-Expanded Graphite in Li-Intercalational Electric Current Generation

Dielectric Relaxation in Hydrogen Bonded Urea-Based Supramolecular Polymer N,N'-di(2,2-dipentylheptyl)urea

Biophysical changes induced by cholesterol on phosphatidylcholine artificial biomembranes containing alamethicin oligomers