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  • Author or Editor: P. Bartoš x
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Results of the tests for bunt resistance of the cultivars registered in the Czech Republic and older Czech and Slovak cultivars carried out from 1988 to 2005 are presented. In most experiments mixture of samples of T. tritici and T. laevis from different locations was applied for inoculation. In 1995 samples of above mentioned species were used separately. Of the older Czech and Slovak cultivars Roxana, Dobrovická přesívka, Hela, Mara and Vala showed high to medium resistance. Of the registered cultivars the highest resistance was displayed by the German cv. Globus and Danish cv. Bill, followed by the Czech cv. Niagara. Ranking of cultivars tested in 2004 and 2005 varied, except the most resistant cultivars Globus, Bill and Niagara.

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Abstract  

A magnetic sorbent based on a mixture of magnetic iron and nickel oxides, and specific surface activation by ferrocyanide solution for enhancement of cesium adsorption is described. After equilibration of clay or soil suspension with the magnetic sorbent, the latter can be removed with exchangeable radiocesium and radiostrontium by means of magnetic separation. The distribution coefficients of the order 2·103 l/kg for cesium and 5·103 l/kg for strontium were determined. The efficiency of the sorbent was investigated in a 1% montmorillonite or soil suspension. At a soil:sorbent ratio 1:1–1:6 in the suspension, the fraction of exchangeable radiocesium in soil at a 2 hours contact was diminished from 56–59% to 48–12%, the decontamination factor of both the mobile cesium and strontium is about 3. The multistage process and sorbent recycling need further investigation.

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Abstract  

Aqueous two-phase systems allow partition of metal ions in nondenaturing conditions. From the fresh skim bovine milk spiked with212Pb and agitated with 4% water solution of apple pectin (degree of esterification-70%), less than 2.3% is recovered to the pectin phase and in the case of pasteurized milk less than 3.0%. Complexation with chelate forming agents was studied. Aminoacids as glycine, alanine and histidine do not exert influence on the yield, but the recovery in the pectin phase was 22% for cysteine, and 80% in the case of EdtacalTM (calcium salt of ethylenediaminetetraacetic acid). The retention of lead in milk phase is extraordinarily high as compared to strontium and corresponds to the behavior of trivalent ions.

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The high-performance size-exclusion chromatography (HPSEC) and radiochromatography (HPSERC) was used for the identification of radiocesium and radiostrontium interaction with humic acid. It was found that the behavior of humic acid on size-exclusion chromatography is sensitive to the salt concentration and pH of the mobile phase. At lower ionic strength and in acidic region of pH, the Aldrich humic acid exhibited three main fraction within the ranges >760 kDa, 25–100 kDa and <5 kDa. Radiocesium was found in the low-molecular fractions (<1 kDa) of humic acids but radiostrontium interacts preferably with the fractions of humic acid of molecular weight within the range 2–5 kDa.

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In 2013–2015 virulence in the wheat leaf rust population was evaluated on 17 Thatcher near-isogenic lines with leaf rust resistance genes. A total of 110 wheat leaf rust isolates were analyzed. Resistance genes Lr9 and Lr19 were effective to all tested isolates. Genes Lr24 and Lr28 conditioned resistance to 92% of the tested rust isolates. Thirty-seven winter wheat cultivars registered in Slovakia were analyzed for the presence of Lr10, Lr24, Lr26, Lr34 and Lr37 using tightly linked molecular markers. Gene Lr37 was the most common in the tested cultivars. Leaf rust resistance was also tested in 13 wheat cultivars at the seedling stage with representative pathotypes of leaf rust.

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Abstract  

The temperature dependence of positron annihilation characteristics, 3 andI 3, has been studied on sample of poly(butadiene), poly(isobutylene) and poly(chloroprene). The temperature range was between 15 and 470 K. The rate of expansion of holes or free-volume in all samples was deduced belowT g as well aboveT g as appr. 3·10–3 K–1 and 2·10–2 K–1, respectively. These values are very close to the rate of the mean squared displacement of scatterer<r 2>observed in neutron scattering experiments. A possibility to use an inverse value of free-volume,V f –1 for study of viscoelastic state of polymers is demonstrated.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: A. Paulenová, P. Rajec, J. Kandráč, G. Sasköiová, E. Tóthová, P. Bartoš, V. Švec, and R. Góra

Abstract  

Complexation equilibrium of metals by three humic acids of different origin with ultrafiltration method was investigated at pH 4 a 5 and ionic strength I = 0.1M NaClO4. Commercial (Aldrich) and two original humic acids (peat and soil, obtained by six step isolation process from the material from Trnava county, close to the NPP Jaslovské Bohunice) were used in this study. For the evaluation of the results, the model of metal ion charge neutralization upon humic acid functional group proposed by the Kim and Czerwinski was used. Complexation constants were calculated using the terms of this model (operational concentration, loading capacity). The values of log = 5.39±0.16 for yttrium, 6.15±0.16 for americium and 5.20±0.08 for lead were found. Correlation of free metal concentration and ratio of molar fraction of complexing functional groups confirms the validity of charge neutralisation model for metal and polyelectrolyte complexation study.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: G. Skarnemark, A. Ödegaard-Jensen, J. Nilsson, B. Bartos, E. Kowalska, A. Bilewicz, and P. Bernhardt
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