The correlation between the vibrational and electron excitation modes in the energy spectra of single-layer graphene and crystalline graphite, as well as the dispersion dependences of those modes, has been studied. The methods of the theory of projective representations of the point and spatial symmetry groups are used for the first time in order to interpret those correlations. The correlations of vibrational and electron excitation spectra and the compatibility conditions for irreducible projective representations in the descriptions of quantum states of graphene and crystalline graphite at various points of their Brillouin zones are determined. For the projective representations of all projective classes belonging to the hexagonal system, standard factor-systems are constructed for the first time. In particular, the factor-systems for electron states are first determined. The results obtained are used to calculate, also for the first time, the correct spinor multiplication tables, i.e. the multiplication tables for elements in double symmetry groups. The developed method is applied to classify all high-symmetry points in the Brillouin zones of single-layer graphene and crystalline graphite with respect to the symmetry type of vibrational excitations.K e y w o r d s: spinor representation of symmetry groups, factor-system, dispersion of elementary excitations.

CdS nanoparticles have a great potential for application in chemical research, bioscience and medicine. The aim of this study was to develop an efficient and environmentally-friendly method of plant-based biosynthesis of CdS quantum dots using hairy root culture of Linaria maroccana L. By incubating Linaria root extract with inorganic cadmium sulfate and sodium sulfide we synthesized stable luminescent CdS nanocrystals with absorption peaks for UV-visible spectrometry at 362 nm, 398 nm and 464 nm, and luminescent peaks at 425, 462, 500 nm. Transmission electron microscopy of produced quantum dots revealed their spherical shape with a size predominantly from 5 to 7 nm. Electron diffraction pattern confirmed the wurtzite crystalline structure of synthesized cadmium sulfide quantum dots. These results describe the first successful attempt of quantum dots synthesis using plant extract.PACS81.07.Ta; 81.16.-c; 81.16.Rf

Drug targeting to specific organs and tissues is one of the crucial endeavors of modern pharmacotherapy. Controlled targeting at the site of action and reduced time of exposure of nontargeted tissues increase the efficacy of the treatment and reduce toxicity and side effects, improving compliance and convenience. Nanocarriers based on the branched copolymers dextran-graft-polyacrylamide were synthesized and characterized and were tested on phagocytic cells. It was shown that these nanoparticles are actively captured by phagocytic cells and that they are not cytotoxic. The polymer nanoparticles loaded with cisplatin at different concentrations from 0.1 to 10 μg/mL yielded dose-dependent decrease in viability of chronic myelogenous leukemia and histiocytic lymphoma cells. The lowest percentage of viable cells was observed for lymphoma cells (22%). Taking into account the fact that our nanoparticles will act mainly on malignant phagocytic cells and do not affect healthy cells, they can thus potentially be used for the therapeutic treatment of tumor cells having phagocytic activity. The effect of nanosilver on cell viability was lower than the one of polymer/cisplatin composite. The data from the cytotoxic studies indicate that nanosilver induces toxicity in cells. However, when the copolymers were conjugated to both nanosilver and cisplatin, such a nanosystem displayed less cytotoxic effect compared to the conjugates of dextran-polyacrylamide and cisplatin.

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An anomalous inverse hysteresis behavior of the thermally induced LCST structural phase transition in dextran-graf t-PNIPAM copolymer macromolecules with Au nanoparticles has been observed by means of surface plasmon extinction and dynamic light scattering spectroscopy. Namely, the phase transition at heating occurs at temperature lower than one occurs at cooling. The inverse character of observed hysteresis has been rationalized to be caused by Au nanoparticles which play the key role in the change of the "sign" of the hysteresis. Also, Au NPs counteract the formation of PNIPAM aggregates in the solution. Moreover, it has been shown that the PNIPAM macromolecule shrinking at heating leads to an unexpected decrease of the surface plasmon peak area, its blue-shift, and narrowing. Such effects have been rationalized as the result of the sharp jump-like decrease of the refractive index of PNIPAM polymer occurring at the phase transition. It has been found that the observed LCST phase transition is reversible.

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Structural transformations in D-g-PNIPAM/AuNPs hybrid nanosystem arise from the synergetic action of plasmonic heating and attractive optical plasmonic forces.