Non-stationary thermophysical characterization of exfoliated graphite with carbon nanotubes composites

The sheet samples of thermally exfoliated graphite (TEG) carbon nanotubes (CNT) composites (TEG CNT cs) were obtained by persulphate oxidation using chemical (CO) and electrochemical (anode) oxidation (ECAO). Electron microscopy reveals multi layered structures of few layer graphene nanosheets with folded and tubular like fragments.Electron microscopy reveals multilayered structures of few layer graphene nanosheets with folded and tubular like fragments. The effective thermal diffusivity values were estimated by nonstationary photo-pyroelectric thermophysical characterization using the heat pulse and thermo-wave modulation methods. Comparison with other carbon (C) based thermal management materials shows that TEG CNTcs exhibit thermal diffusivity, effusivity and conductivity comparable with those of actual C polymer and C C composites. For TEG CNT cs, evaluated values of phonon mean free path (MFP) and relaxation time (RT) are in the ranges estimated for defective graphene. The values of diffusivity and effusivity, MFP and RT are lower for denser TEG CNT cs obtained by ECAO and are higher for less dense TEG CNT cs obtained by CO. The obtained diffusivity and effusivity values designate TEG CNT cs as suitable thermal management materials.Comment: 33 pages, 5 figure

Carbon Adsorbents and Catalysts Produced from Worked out Gas Mask Cartridges

It is offered here the procedure of utilization of gas mask or respirator charge when operation term is expired. This technique enables to get not only high quality active carbon but also its oxidized variety that has properties of polyfunctional carboxylic cationite and catalyst decomposition of hydrogen peroxide (catalysis activity). Structure-sorption properties of the obtained adsorbents are listed below

Случай ботулизма у ребенка грудного возраста

Presents a clinical case, demonstrating the complexity of differential diagnosis of botulism of a child on the first year of life. The tactic of laboratory research, the therapy and the clinical result of the treatment was described.Представлено клиническое наблюдение, демонстрирующее сложность дифференциальной диагностики ботулизма у ребенка первого года жизни. Описана тактика лабораторного обследования, подходы к терапии и клинический результат проведенного лечения

Каталазоподібна активність вуглецевих нанотрубок із нанесеним нанорозмірним оксидом церію

Ряд нанокомпозитів вуглецеві нанотрубки – CeO2 із різним вмістом нанооксиду церію було синтезовано реакцією осадження нітрату церію у водних розчинах без стабілізатора за кімнатної температури. Кількість нанесеного оксиду церію в нанокомпозиті варіюється в межах від 0,66 до 15,29 %. Каталазоподібну активність нанорозмірного оксиду церію, вихідних вуглецевих нанотрубок та їхніх нанокомпозитів було досліджено в реакції розкладання пероксиду водню за рН 8–11. Більшість синтезованих нанокомпозитів виявляють каталітичну активність вищу, ніж ненанесений нанооксид церію за всіх рН. Знайдено екстремальну залежність від рН ензимоподібної активності матеріалів, що містять нанорозмірний оксид церію, із рН оптимумом 9,5–10,5. Показано, що нанокомпозити з меншим вмістом нанооксиду церію більш активні в реакції розкладання пероксиду водню. Це пояснюється агломерацією часток нанооксиду із зростанням вмісту оксиду, що призводить до зменшення питомої поверхні та поверхневих Се3+/Се4+ дефектів.A series of CNT – CeO2 nanocomposites with different nanoceria content was synthesized by reaction of cerium nitrate deposition in the aqueous media without stabilizers at room temperature. The amount of deposited cerium oxide in nanoсоmposite varies from 0.66 to 15.29 %. The catalase-mimetic activity of nanoceria, pristine CNT and its nanocomposites was studied in the reaction of hydrogen peroxide decomposition in the pH range of 8–11. Most of synthesized nanocomposites turned out to be effective catalysts and have a better catalytic activity than non-deposited nanoceria at all pH-values. It was established that enzyme-mimetic activity of nanoceria containing materials extremely depended on pH with the pH-optimum of 9.5–10.5. It was shown that nanocomposites with the lowest nanoceria content are more active in the reaction of hydrogen peroxide decomposition. It can be explained by the agglomeration of the nanoparticles with the increase of ceria amount in nanocomposite that causes the surface area reduction and decrease in the surface Се3+/Се4+ defects content

Change in the Microviscosity of Erythrocyte Membranes and Proteins in Blood Plasma after Graphene Oxide Addition: The ESR Spectroscopy Study

The change in the microviscosity of erythrocyte membranes and the proteins in blood plasma after graphene oxide addition is studied by the ESR spectroscopy exploiting two spin probes with different lipophilic components in the structures. Experiments with charged spin probe 2 embedded into the erythrocyte membrane showed that the introduction of graphene oxide in small concentrations (∼70 μg/ml) into a suspension of erythrocytes did not lead to significant changes in the microviscosity of their membranes. Correlation times of hydrophobic spin probe 1 adsorbed to hydrophobic pockets of plasma proteins demonstrate a gradual slowdown at the graphene oxide injection into blood plasma that indicates a small deformation of the hydrophobic cavity of protein at the adsorption. However, this protein binding with graphene oxide does not cause the displacement of the spin probe from their hydrophobic cavities, which is evidence about small changes in the protein secondary structure. The obtained results indicate the insignificant cytotoxicity effect of small concentrations of graphene oxide for erythrocytes and blood plasma

Case of infant botulism

Presents a clinical case, demonstrating the complexity of differential diagnosis of botulism of a child on the first year of life. The tactic of laboratory research, the therapy and the clinical result of the treatment was described