Evaluation of fullerenes C<inf>60</inf>/C<inf>70</inf> layers in polystyrene thin films by neutron and X-ray reflectometry

Thin films of polystyrene-fullerene C60 and C70 nanocomposites are investigated by X-ray, neutron reflectometry and AFM. These films were prepared by spin coating from toluene solutions with fullerene content of 1, 3, and 5 wt % relative to polystyrene mass. The concomitant to spin-coating formation of aggregates, larger for C70, was observed. Still, a formation of an enriched layer of fullerenes with a thickness up to 5 nm was detected after model fitting of the reflectivity curves

Model System for Antiviral Peptide Transport Characterization

Abstract: Determination of the mechanism of action of potential medicinal substances is an integral stage in development of novel drugs. The interaction of antiviral peptide PB16–14 with lipid membranes in cell and cell-free model systems is demonstrated. Penetration of a fluorescently tagged analog of peptide into cells has been observed for 15 min using continuous-flow cytofluorometry and confocal microscopy. The specific features of interaction of the peptide under study with cell membranes have been studied using small-angle neutron scattering (SANS), atomic force microscopy (AFM), and dynamic light scattering. It is shown that model liposomes (PC/PG) increased in size in the presence of peptide (in a 5% ethanol/5% DMSO/PBS buffer), while the ζ potential changed only slightly, which can be interpreted as a consequence of a change in the surface charge and may indicate peptide ability to interact with a lipid bilayer (not excluding its penetration into the membrane). The data obtained can be used both for studying the mechanism of therapeutic peptide transport and for developing drug-delivery agents

The first amorphous and crystalline yttrium lactate: Synthesis and structural features

The synthesis and crystal structure of the first molecular yttrium lactate complex, Y(Lac)3(H2O)2, is reported, where the coordination sphere of yttrium is saturated with lactate ligands and water molecules, resulting in a neutral moiety. In Y(Lac)3(H2O)2, hydrogen bonding between α-hydroxy groups and water molecules allows for the formation of 2D layers. A subtle variation in synthetic conditions, i.e. a slight increase in pH (5.5 instead of 4.5) promoted the formation of a semi-amorphous fibrous material with a presumed chemical composition of Y4(OH)5(C3H5O3)7·6H2O. The flattened fibres in this material are responsible for its good flexibility and foldability

A sol-gel synthesis and gas-sensing properties of finely dispersed ZrTiO4

The transparent titanium-zirconium-containing gel was obtained using heteroligand coordination compounds (namely, alkoxoacetylacetonates) as the precursors. The high-dispersive system “ZrTiO4 – carbon” formed after drying of such gel and carbonization of the obtained xerogel, was used to study the evolution of microstructure for the product (ZrTiO4) during thermal treatment in air for 1 h in the temperature range from 500 °C to 1000°С. It was stated that the formation of crystalline phase occurred in the narrow range 690-730°С. The thermal treatment at 500 °C and 600°С allowed obtaining micro- and mesoporous X-ray amorphous products of the composition ZrTiO4, with the specific surface area falling in the range 82–150 m2/g. At the higher temperatures the single-phase nanocrystalline powder was prepared (the specific surface area amounted to 2.5–15 m2/g). Particle coarsening took place more extensively at temperatures ≥700°С was shown. For the ZrTiO4 nanopowder crystallized under the mildest conditions at the temperature of 700 °C, chemoresistive gas-sensitive properties were studied for the first time. The material showed a high reproducible response at 1–20% O2 and 200–10,000 ppm H2 at a relatively low detection operating temperature of 450 °C. © 2019 Elsevier B.V