The diffusion of sulfur dioxide into partially iodine-doped poly (3-dodecylthiophene) and poly(hexadecylthiophene) has been studied. A direct dependence of the diffusion rate on the alkyl group lengths was ascertained. The diffusion rate could be increased by irradiation of the polymers.
The influence of certain gases on the properties of thermally treated and -irradiated Langmuir-Blodgett (LB) films of poly (3-hexadecylthiophene) and stearic acid has been studied. Both the heat and -radiation brought about some structural surface layer changes, leading to temporal variations of the course of the in-plane conductivity of films affected by the presence of applied gases.
The influence of -radiation on the electric properties of Langmuir-Blodgett (LB) films of partially iodine-doped poly-(3-hexadecylthiophene) and stearic acid in interaction with selected environment-polluting gases has been studied. CO2, CO and NO2 increase the LB films conductivity and NO has a tendency to decrease the electric conductivity. The influence of -radiation was expressive onyl in the case of CO2, whereas NO2 brought about degradation of the conductive polymer.
Authors:J. Marešová, L. Remenárová, M. Horník, M. Pipíška, J. Augustín, and J. Lesný
The aim of this paper was to obtain quantitative data of foliar uptake kinetics and long distance transport of zinc in tobacco
(Nicotiana tabacum L.) and hop (Humulus lupulus L.) plants. Zinc was used as a model of microelement and toxic metal, tobacco and hop as a representatives of agriculturally
important plants. A tip of leaf blade was immersed in the solution spiked with 65ZnCl2 and foliar uptake and translocation to other parts of the plant grown in nutrient solution was measured by gamma-spectrometry
and autoradiography. We found that foliar zinc uptake by both plants is dependent on the initial metal concentration within
the range C0 = 10–100 μmol dm−3 ZnCl2. Zinc is immobilized mainly in immersed part of the contact leaf and only <1% is transported to non-immersed parts of the
leaf. At C0 = 0.1 mmol dm−3 ZnCl2 concentrations >2.5 mg/g Zn and 4.8 mg/g Zn (dry wt.) in immersed part of tobacco and hop leaf plant, respectively were found
after 5 days of exposure. Low mobility of zinc entering the plant via the leaf surface can be attributed to the immobilization
of zinc into Zn–ligand complexes with high stability constants log K at pH 6.0–8.0, such as the reaction products of Zn2+ ions with citric acid, histidine or phosphates. Zinc can be extracted from dried leaves by the solutions of inorganic salts,
carboxylic acids, amino acids and synthetic complexing ligands such as EDTA. Anionic (SDS) and non-ionic (Tween 40) surfactants
causes the decrease of the Zn foliar uptake, but not translocation of Zn from the contact leaf area. Obtained data are discussed
from the point of view of possible limited efficiency of liquid formulations designed for practical applications as Zn foliar
Authors:J. Lesný, J. Tölgyessy, L. Čulák, J. Klas, B. Novruzi, and A. Çela
Trace amounts of progesterone were determined by sub- and super-equivalence isotope dilution analysis in model solutions and cow's milk. The samples were labelled with 11--hemi-succinate-/125I/-iodotyrosine methylesther progesterone and the separation of antibody-bound from free hormone was performed by adsorption on carbosorb. RIA-test-PROG M kit /SSR/ was used for reference analysis. The method is suitable for pregnancy testing.
Authors:Z. Koreňová, J. Lesný, J. Jagnešáková, T. Miškovič, O. Rohoň, and J. Tölgyessy
Sub- and super-equivalence method of isotope dilution analysis /variant CCV/ was applied for the determination of trace of strontium in radioactive solutions in the presence of about 1000-times larger amount of calcium. DC-18-C-6 crown ether was used as a selective reagent. Picrate anion was chosen as a complementary ion.