Synthesis, Characterization and Photocatalytic Efficiency of ZnO/MWCNT Nanocomposites Prepared Under Different Solvent Conditions.

Here we report the application of zinc oxide (ZnO) coated multi-walled carbon nanotube (MWCNT) composites in the photocatalytic decomposition of acetaldehyde (AA). Zinc oxide nanoparticles were successfully coated on the multi-walled carbon nanotube via impregnation process using zinc acetate (Zn(CH3COO)2×2H2O) as precursor and sodium dodecyl sulfate (SDS) treated multiwalled carbon nanotube as raw material under different solvent conditions. The applied solvents during preparation were ethanol (EtOH) and water (H2O). As-prepared materials were characterized by thermal analysis (TG), X-ray diffraction (XRD), specific surface area measurement (BET) and transmission electron microscopy (TEM) techniques. Photocatalytic efficiencies of as-prepared composites were investigated in a stationary reactor equipped with UV lamp. Decomposition of acetaldehyde was followed by using gas chromatography (GC). Observations revealed that using impregnation method and different solvents the preparation of ZnO/MWCNT nanocomposites can be controlled easily. The highest degradation rate was achieved with the nanocomposite was synthetized using ethanol as solvent. The photocatalytic experiments revealed that the composite has higher photocatalytic activity than that of both the zinc oxide nanoparticles and the mechanical mixture of multi-walled carbon nanotube and zinc oxide.

[Studies on the genotoxic effects of crude liver oils from 3 species of Mediterranean sharks by means of in vitro micronucleus test using human lymphocytes]. / Etude de l'effet génotoxique des huiles hépatiques brutes de trois espèces de requins méditerranéens par application du test de numération des micronoyaux dans les lymphocytes T humains.

Lymphoid system tumours have been identified in two subjects who used to handle for several years mediterranean shark liver oil and squalen extracted from this oil. Moreover, scientific data, reported in 1959 by Kröning, show the induction of lymphoid tumours in C57 B1 mice after exposure of their skin to squalen. These observations rose the question of a possible mutagenic power of shark liver oil. In order to determine the genotoxicity of these oils, in vitro assays have been performed on crude hepatic oil of three species of mediterranean sharks: two benthic sharks, Centrophorus granulosus and Galeus melastomus, and one pelagic specie, Prionace glauca. Genotoxicity of oils have been assayed using a micronucleus test which can detected simultaneously clastogen and aneugen effects. The incubation of human cells with the hepatic crude oils of Centrophorus granulosus increases the rate of the binucleated micronucleated cell in a dose dependent manner. The mean micronucleated cell rate was 9.0%. +/- 1.1 in controls and increased up to 27,1%. +/- 4,0 for the highest concentrations of oil extracts. Similar results have been obtained with crude hepatic oils of Galeus melastomus and Prionace glauca. The results of this experimental study show that the crude liver oils of three species of sharks are genotoxic and confirm a high carcinogenic risk.

[Application of micronucleus test for the demonstration of antimutagenic properties of natural substances]. / Application du test des micronoyaux à la mise en évidence des propriétés antimutagènes de substances naturelles.

Authors have used a reliable and reproductible original model of controlled production of free radicals for the cytokinesis-block micronucleus assay. This mutagenicity test is of easy realization and quick interpretation. An experimental model is proposed to test mutagenic activity of free radical generators and antioxydant properties of many substances, such as ascorbic acid. Its addition to the culture medium showed a significant decrease in the rate of micronucleated cells exposed to the free radical generator. The study of other antioxydant compounds (beta-caroten and 5-hydroxyquinolin) have confirmed results previously obtained with ascorbic acid. Thus, the free radical generator coupled to the cytokinesis-block micronucleus assay represents a reliable test to study and evaluate the antioxydant power of natural substances.

Impact of weather changes on the growth of the unicellular Blepharisma undulans (Stein).

The growth of Blepharisma undulans (Stein) cells durably treated and not treated with insulin was followed up for three months with special regard a possible impact of meteorological factors on the growth rate. The growth rate of the protozoon was not appreciably altered by weather changes but the growth curves for cells treated and not treated with insulin indicated opposing trends of multiplication under the influence of approaching weather fronts. Warm fronts which have a parasympathic effect and cold fronts which have a sympathetic effect uniformly enhanced the growth rate of the untreated cells and retarded that of the insulin treated cells.

[Weather front sensitivity as an influencing factor in the onset of labor]. / Frontérzékenység, mint a szülésmegindulás idejét befolyásoló tényezö.

The connection between meteorological stimuli and the onset of labor was examined on the basis of the patients' front-sensitivity. Front-sensitivity was tested by a questionary containing 60 questions. Converse relation was observed between the degree of sensitivity and the gestational age. A sudden rise of onsets of labors could be shown during frontal changes, occurred after meteorologically quiet periods. During frontal changes the ratio of onsets of labors rose significantly among those patients who were sensitive tho the given front. This effect could be observed during a longer period of frontal influence. By the authors opinion also meteorological stimuli can be regarded as one of the factors, determining the actual date of onset of labor among front-sensitive women.