National Repository of Grey Literature 109 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Measured and modelled fluxes of tropospheric ozone in mountainous Norway spruce forest
Juráň, Stanislav ; Zapletal, Miloš ; Večeřa, Zbyněk ; Cudlín, Pavel ; Urban, Otmar
Tropospheric ozone fluxes (O3) were measured in Norway spruce forest at Bily Kriz, Czech Republic by eddy covariance technique. Within-canopy concentration gradient was measured by APOA-370 analysers (Horiba, Japan) in 7m, 25m and 30m above ground. Fluxes of O3 were modelled from the concentration gradient by applying Inverse Lagrangian Transport Model (Raupach, 1989). Next, O3 fluxes were modelled on the basis of resistent analogy. Ozone flux measured by eddy covariance technique amounted up to 1.19 nmol m-2 s-1 on daily average and the lowest -0.75 nmol m-2 s-1. Studied forest stand was net sink for ozone in 7.14 mmol m-2 per day (=0.343 g m-2 per day). The highest ozone emission peaked during noon hours, suggesting closure of stomata due to low air temperature and ozone production due to sufficient radiation. Both models proved to be imprecise when compared to measured data in autumn-winter transition period.
Rössner ml., Pavel ; Vrbová, Kristýna ; Strapáčová, S. ; Rössnerová, Andrea ; Ambrož, Antonín ; Brzicová, Táňa ; Líbalová, Helena ; Javorková, Eliška ; Zajícová, Alena ; Holáň, Vladimír ; Kulich, P. ; Večeřa, Zbyněk ; Mikuška, Pavel ; Coufalík, Pavel ; Křůmal, Kamil ; Čapka, Lukáš ; Dočekal, Bohumil ; Šerý, Omar ; Machala, M. ; Topinka, Jan
We analyzed gene expression changes in the lungs and the immunological response in splenocytes of mice exposed by inhalation of ZnO nanoparticles - NP. Adult female ICR mice were treated for three days and three months, respectively. Analysis of differential expression in genes involved in oxidative stress was conducted using quantitative RT-PCR. The potential immunotoxic and immunomodulatory effects of ZnO NP were analyzed by phenotyping and cytokine production by splenocytes after three months exposure. Three days exposure resulted in down-regulation of GCLC, GSR, HMOX-1, NQO-1, NF-kB2, PTGS2 and TXNRD1 mRNA expression, three months exposure increased the expression of these genes. Three months exposure caused a significant decrease in the percentage of granulocytes in the spleen cells, and affected the production of IL-10 and IL-6 by lipopolysaccharide-stimulated leukocytes. In summary, our study revealed changes in the expression of genes involved in the oxidative stress response following acute ZnO NP exposure. Subchronic ZnO NP exposure induced immunomodulatory effects in the spleen.
Determination of permeability of ulra-fine lead oxide aerosols through military filters
Kellnerova, E. ; Večeřa, Zbyněk ; Kellner, J. ; Zeman, T. ; Hylak, Č.
Military filters introduced in the Army of the Czech Republic are most commonly used when working with combat equipment and weapons and in manoeuvring activities in the terrain with the use of explosives or chemical warfare agents. During such activities, a large number of pollutants in the form of nanoparticles are released. Nanoparticles, irrespective of their chemical composition, are classified as carcinogenic to humans and therefore it is necessary to eliminate them from the air. Military filters, especially the combined ones, which contain a filtration as well as sorption component, are most widely used and are designed for the widest range of pollutants. However, the current methodology to evaluate the effectiveness of military filters does not fix a duty to monitor the ability of the filters to capture relevant pollutants across the whole range of sizes. The paper evaluates the efficiency of selected types of military filters using the methodology and instrumentation introduced in the accredited laboratories of the Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic. The testing has been carried out simultaneously with two concentrations of ultra-fine aerosols containing lead oxide nanoparticles ranging in size from 7.6 nm to 299.6 nm. It is an aerosol, the physicochemical and toxicological properties of which are known. During the work the basic parameters of permeability of aerosols tested by filters have been evaluated, especially: size and number of particles in front of and behind the filter, the efficiency and penetration of nanoparticles by the filter.
Effect of inhaled metal oxide nanoparticles on organs of exposed mice
Mikuška, Pavel ; Večeřa, Zbyněk ; Dočekal, Bohumil ; Čapka, Lukáš ; Křůmal, Kamil ; Coufalík, Pavel ; Moravec, Pavel ; Buchtová, Marcela ; Míšek, Ivan ; Vrlíková, Lucie ; Smutná, Tereza ; Dumková, J. ; Hampl, A. ; Fictum, P.
Adult mice were continuously exposed to metal oxide nanoparticles for different time intervals. At the end of experiment, mice organs (lung, brain, kidney, liver and spleen) were collected for chemical, biochemical, histological and electron microscopical analyses.
SMV-2017-706: Tests of apparatus for determination of 3H and 14C in air
Večeřa, Zbyněk
Testing of ”V3H14C” apparatus designed for 3H and 14C sampling from the air. The samples are captured into sorbents, silica gel for 3H (THO, T2O), and sodium hydroxide for 14C (14CO2) that are subsequently in laboratory analyzed for quantification of radioactive emissions of 3H and 14C from nuclear power plants e.g.
Characterization of organic compounds in PM1aerosol in Kosetice and Brno in winter season 2017
Křůmal, Kamil ; Mikuška, Pavel ; Večeřa, Zbyněk
In this work, the organic compounds and organic markers used for the identification of sources of aerosols were measured. Monosaccharide anhydrides and resin acids (emissions from biomass combustion) and polycyclic aromatic hydrocarbons (emissions from traffic and incomplete combustion) were observed especially. Hopanes, steranes (traffic, coal combustion) and alkanes were next groups of analysed organic compounds.
Determination of inorganic anions in air by modernized aerosol sampler
Čapka, Lukáš ; Mikuška, Pavel ; Večeřa, Zbyněk
Combination of original ACTJU sampler with water-based condensation growth unit (CGU) located upstream of the ACTJU allows quantitative sampling of aerosol particles down to a few nm in diameter. The ACTJU effluent is permanently sucked out from the sampler and online analysed for particulate water-soluble species by ion chromatography.
Determination of kadmium content in plant tissue of Norway Spruce and European Beech after application of cadmium oxide nanoparticles
Svozilová, Eva ; Mikuška,, Pavel (referee) ; Večeřa, Zbyněk (advisor)
The aim of this thesis is to monitor cadmium content in needles of Norway spruce and European beech leaves after controlled exposure to cadmium oxide nanoparticles and evaluate the potential risks of such nanoparticles to plants. Needles and leaves were harvested after a one-week and two-week exposure and prior to analysis of cadmium content, they were modified using relevant procedures. Samples were mineralized in nitric acid using pressurized microwave mineralizer and subsequently analyzed by atomic absorption spectrometry (AAS) with electrothermal atomization of cadmium content. Based on the results AAS analysis the transport of nanoparticles into the plant tissue of studied species was evaluated, comparing the content of cadmium in one week and two weeks experiment in the washed and unwashed samples of needles and leaves.
Organic compounds in PM1 aerosol in Kladno-Svermov in winter 2017
Křůmal, Kamil ; Mikuška, Pavel ; Večeřa, Zbyněk
The work deals with the measurement of organic compounds and organic markers used for the identification of main aerosol sources in PM1 aerosol in a small town (Kladno-Švermov) near Prague. Monosaccharide anhydrides and resin acids (emissions from biomass combustion) were found especially. Polycyclic aromatic hydrocarbons (emissions from traffic and incomplete combustion), hopanes (traffic, coal combustion), steranes (traffic), saccharides and alkanes were other groups of analysed organic compounds.
SMV-2016-719: Detection and identification of sources of nanoparticles produced by military equipment
Večeřa, Zbyněk
In the study, which took place in a military training area "Vyškov" and simulators University of Defence, we monitored and identified the sources nanoparticles produced various kinds of military equipment. Preliminary results indicate that the source of nanoparticles are especially exhaust gases of engines powering military equipment and studied after shoot fumes. Potential impact of nanoparticles on the service staff of military equipment is currently being evaluated.

National Repository of Grey Literature : 109 records found   1 - 10nextend  jump to record:
See also: similar author names
2 Večeřa, Zdeněk
Interested in being notified about new results for this query?
Subscribe to the RSS feed.