Authors:P. Neumann, Z. Horváth, P. Nemes-Incze, G. Molnár, G. Vértesy, and L. Biró
We studied the electrical transport properties of indium contacted graphene, few layer graphite (FLG) and bulk graphite samples under ambient conditions. Some of the contacted samples showed nonlinear transport characteristics. The initial electrical properties of the samples were changed reversibly by light illumination and irreversibly by argon ion irradiation. Ion irradiation modified the nonlinear I–V characteristics to quasi-linear ones in many cases. The resistance of a graphene sample showed positive temperature coefficient.
Authors:Melinda Zomborszky-Kovács, L. Bárdos, H. Bíró, S. Tuboly, Erzsébet Wolf-Táskai, Á. Tóth, and P. Soós
The effect of synthetic beta-carotene and synthetic nucleotide base on daily weight gain, feed consumption and certain haematological, biochemical and immunological parameters of piglets were studied in a 3-week experiment. Beginning one week prior to weaning, the diet fed to one experimental group of piglets was supplemented with 10% Rovimix Beta-carotene at 875 mg/kg of diet. Synthetic uracil and adenine (98%, Sigma-Aldrich) were mixed into the diet of the other experimental group at doses of 500 mg/kg of diet for each substance. The control group received the basic diet without any supplementation. The changes observed over time in the haematological parameters and in certain biochemical variables could be regarded as physiological. By day 21 of the experiment, beta-carotene supplementation had significantly lowered the neutrophilic granulocyte percentage and elevated the lymphocyte percentage, while in the other two groups a change of opposite tendency occurred. At the end of the experimental period there was a decrease in plasma vitamin E concentration due to carotene supplementation (control: 6.1 ± 1.5, nucleotide: 6.3 ± 2.5, carotene: 2.3 ± 1.5 mg/L). Lymphocyte blastogenesis induced by phytohaemagglutinin and concanavalin A increased by 50 and 130%, respectively, in the nucleotide group and by 60 and 30%, respectively, in the carotene group, while it did not change in the control group. The supplements exerted no positive effect on the in vivo cellular immune response.
Authors:B. Panwar, I. Kádár, B. Bíró, K. Rajkai-Végh, P. Ragályi, M. Rékási, and L. Márton
Phytoremediation is an approach designed to extract excessive heavy metals from contaminated soils through plant uptake. Cadmium (Cd) is among the elements most toxic to living organisms. Health hazards associated with the lethal intake of Cd include renal (kidney) damage, anaemia, hypertension and liver damage. A greenhouse experiment was carried out with Indian mustard (Brassica juncea) grown on artificially spiked soil (100 μg Cd g−1) with EDTA (2 mmol kg−1 in 5 split doses), FYM, vermicompost (VC) and microbial inoculants (MI) such as Azotobacter sp. and Pseudomonas sp. The growth of Brassica juncea L. was better in soil amended with FYM or VC as compared to unamended Cd-polluted soil. Growth was slightly suppressed in EDTA-treated soil, whereas it was better after treatment with MI. The application of FYM and VC increased the dry matter yield of Indian mustard either alone or in combination with microbial inoculants, while that of EDTA caused a significant decrease in the biomass of Indian mustard. The application of microbial inoculants increased the dry matter yield of both the roots and shoots, but not significantly, because MI shows greater sensitivity towards cadmium. The maximum cadmium concentration was observed in the EDTA +MI treatment, but Cd uptake was maximum in the VC + MI treatment. The Cd concentration in the shoots increased by 120% in CdEDTA over the Cd100 treatment, followed by CdVC (65%) and CdFYM (42%) in the absence of microbial inoculants. The corresponding values in the presence of MI were 107, 51 and 37%, respectively. A similar trend was also observed in the roots in the order CdEDTA+M > CdVC+M > CdFYM+M>Cd100+M.MI caused an increase in Cd content of 5.5% in the roots and 4.1% in the shoots in the CdEDTA+M treatment compared with the CdEDTA treatment. FYM, VC and EDTA also increased Cd uptake significantly both in the shoots and roots with and without microbial inoculants.The results indicated that Vermicompost in combination with microbial inoculants is the best treatment for the phytoremediation of Cd-contaminated soil by Indian mustard, as revealed by the Cd uptake values in the shoots: CdVC+M (2265.7 μg/pot) followed by CdEDTA+M (2251.2 μg/pot), CdFYM+M (1485.7 μg/pot) and Cd100+M (993.1 μg/pot).
Authors:E. Horváth, P. L. Neumann, A. L. Tóth, É. Vázsonyi, A. A. Koós, Z. E. Horváth, P. Fürjes, C. Dücső, and L. P. Biró
The deposition of
nanowires for interconnects in nanoelectronic devices werestudied
morphologically by scanning electron microscopy (SEM), atomic force microscopy
(AFM) and by in-situ resistance measurements. The deposition and basic
characterization of nanometer size tungsten wires by gas injection (GIS) and
focused ion beams (FIB) was carried out in-situ in a LEO 1540 XB workstation.
The I(V) measurement showed that the deposited W wires have ohmic
characteristic. The variation of the resistance during an ex-situ heating was
linear with a low thermal coefficient (4% of the pure metallic W).
Authors:A. Szabo, A. Fonseca, L. P. Biro, Z. Konya, I. Kiricsi, A. Volodin, C. Van Hasendonck, and J. B.Nagy
Some recent results on
the synthesis of coiled carbon nanotubes (CNTs) are summarized. Several
supported catalysts can lead to the formation of coiled CNTs. Interestingly,
certain domains of the coil pitch and coil diameter are favoured, and two
“stability islands”are found in the 3D representation of the number of coiled
CNTs as a function of both coil pitch and coil diameter. It is emphasized that
these nanotubes are formed either by introducing pairs of five-membered ring -
seven-membered ring or by forming haeckelite structures. The coiled CNTs could
be used in nanocomposite reinforcement as well as special sensors based on
their remarkable mechanical and electrical properties.