12 (2006) Scientific papers, Series A
Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/38122
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Článek Otevřený přístup peer-reviewedpublished Anodic stripping voltammetry at bismuth-modified electrodes in ammonia-buffered media(Univerzita Pardubice, 2007) Švancara, IvanIn this contribution, the analytical performance of a bismuth-modified carbon paste electrode (Bi-CPE) in square-wave anodic stripping voltammetry (SWASV) with ammonis buffer-based supporting media (pH 8.6-9.0) has been studied. Possibilities and limitations of such combination used fir the determination of various metal ions were explored with tje electrode of choice, containing 17 % (w/w) Bi, when analysing model solutions with Mn2+, Zn2+, Cd2+, Pb2+, In3+, and Tl+ - added in as either single species or selected mixtures. SWASV of these ions has been investigated focused on the individual peak characteristics, calibration measurements and definition of linear concentration ranges attainable, limits of detections, reproducibility, and interference effects from other ions. The latter was examined in more detail for Zn2+ + Cd2+ + Pb2+ and, particularly, for Tl+ + Cd2+ + Pb2+ mixtures where the formation of intermetallic compounds and low-melting alloys with bismuth had significantly affected the SWASY detection of the respective metals, giving rise to overlapped and additional signals. As shown, these phenomena would represent one of the key-factors which have to be considered when elaborating procedures for practical determinations.Článek Otevřený přístup peer-reviewedpublished Extraction method for determination of Na, K, and Mg in feed mixtures(Univerzita Pardubice, 2007) Krejčová, Anna; Černohorský, Tomáš; Pouzar, MiloslavIn order to imprve the speed at low of cost, a method of analysis of animal feed for sodium, potassium and magnesium by ultrasound-assisted leaching with a mixture of strong acids prior to analysis by flame atomic absorption spectrometry(FAAS) has been proposed. The influence of acid mixture composition, time, temperature and sample mass on the leaching recovery was examined in order to find the most suitable working conditions. The ultrasound- assisted leaching carried out at opzimized conditions (mixture of HNO3, HCl, H2O2, ultrasound bath, 60 °C, 30 min) was established to be a fast and quantitative method for the feed mixture sample preparation before determination of Na and K. Mg was found to be only partially extractable. The microwave ashing procedure was utilized as the standard for comparison of alternative methods of sample preparation. The leaching method followed by FAAS was applied to analyzed feed mixtures and the results indicate that it is appropriate for determination of Na, K content in feed mixtures (recovery for Na 97-101 %, K 97-102%).Článek Otevřený přístup peer-reviewedpublished Mercury dilatometry in physical aging study of a-Se(Univerzita Pardubice, 2007) Svoboda, Roman; Pustková, Pavla; Málek, JiříVolume relaxation of amorphous selenium (a-Se) was studied by mercury dilatometry. Two differently constructed dilatometers (different sensitivity of sample volume change and different values of characteristics time constants of the dilatometers) were used to study the influence of experimental setting on the relaxation measurements. Temperature of glass transition and thermal expansion coefficients in glassy and undercooled liquid state were determined from nonisothermal experiments. Four sets of isothermal experiments including temperature down-jump, up-jump and combined experiments were performed to study the volume relaxation. The Tool-Narayanaswamy-Moynihan model was applied to describe the relaxation behavior of a-Se. All four sets of isothermal experiments were described using one set of TNM parameters. The combined experiments were considered to be most suitable for studying the structural relaxation because of the minimum of the information lost at the beginning of the experiment. The reaction of a-Se and mercury was found not ot be influencing the results of volume relaxation measurements.Článek Otevřený přístup peer-reviewedpublished Mycoplasma hominis in female genital tract and its susceptibility to antibiotics(Univerzita Pardubice, 2007) Vydržalová, Markéta; Lysková, Petra; Mazurová, JaroslavaMycoplasma hominis is a common inhabitant of the vagina of healthy women. It has been linked to pelvic inflammatory diseases such as tubo-ovarian abcess and salpingitis. Mycoplasma hominis is also associated with bacterial vaginosis but it is still unclear whether the organism really contributes to a pathological process in which so many different bacteria are involved. The aim of this study was to determine the incidence of Mycoplasma hominis in the genital tract of women with different clinical symptoms. A total of 3 5 1 cervical swabs were investigated. Mycoplasma hominis was isolated in 83 cases (23.6 %). The positive samples were compared with regard to genital symptoms and age of the women. Mycoplasma hominis was isolated in 33.3 % from pregnant women and 27.5 % from group of 31-40 years old women. Susceptibility of clinical isolates of Mycoplasma hominis was studied to doxycycline, ciprofloxacin and erythromycin.Článek Otevřený přístup peer-reviewedpublished Effect of rape seed oil quality on biodiesel composition(Univerzita Pardubice, 2007) Skopal, František; Machek, Jaroslav; Komers, KarelThe methanolysis of rape seed oil catalyzed by KOH has been studied from the standpoint of the dependences of the acid value (neutralisation number) and concentration of unreacted oil (as sum of glycerides) in the final mixture of methyl esters of fatty acids on the oil (biodiesel) on the initial KOH concentration in methanol and on the acid value and water content of the used oil.Článek Otevřený přístup peer-reviewedpublished 13C{1H, selective 119Sn} NMR experiment as a tool for determination and assignment of nJ(119Sn, 13C) coupling constants(Univerzita Pardubice, 2007) Lyčka, Antonín; Holeček, Jaroslav13C {1H, selective 119Sn} NMR experiment is an effective one-dimensional technique for determination and assignment of nJ (119Sn, 13C) coupling constants in organotin compounds containing two or more tin atoms in a molecule. Signals of 119Sn satellites are decoupled and, thus, "removed" from the 13CNMR spectra. For one-bond tin-carbon coupling constants, only 1J(117Sn, 13C) coupling constants are visible while for much smaller long-range tin-carbon coupling constants, for which 119Sn and 117Sn satellites are not separated, relative integral intensities are reduced approximately to a half with respect to those carbons for which selective 119Sn decoupling is not effective.Článek Otevřený přístup peer-reviewedpublished Apparatus for observation and measurement of properties of electro-optic cells with ferroelectric liquid crystals(Univerzita Pardubice, 2007) Pirkl, Slavomír; Dařbujan, JosefThe apparatus for investigation of the behavior of ferroelectric liquid crystals in an electric field and for measurement of their spontaneous polarization is described. Function of the apparatus was tested by observations and measurements properties of several ferroelectric compounds with a high spontaneous polarization.Článek Otevřený přístup peer-reviewedpublished Transformation company management systems in Czech chemical industry(Univerzita Pardubice, 2007) Hyršlová, Jaroslava; Branská, Lenka; Špaček, LadislavIn relation to companies entering the global market environment, the need to carry out the company management with regard to the quality, environment and health and safety has been increasing. To provide for this requirement, companies implement the management systems (i.e. quality management systems, environmental management systems and health and safety management systems). The authors of the paper carried out a research in the second half of 2005 to analyze the current state of the management systems implementation at enterprises of the selected industry sector (including the options of their integration). They focused on chemical enterprises in the Czech Republic. The research realized in cooperation with the Association of Chemical Industry of the Czech Republic aimed at the types of management systems, at the reasons for their implementation and at their real effects and drawbacks. Furthermore, the attitudes of the chemical company management to building or transfer to the integrated management systems were the centre of attentation. The paper summarizes the objectives, methodology and main conclusions of the primary research.Článek Otevřený přístup peer-reviewedpublished Antagonistic effects of pseudomonas SPPon Arcobacter butzleri(Univerzita Pardubice, 2007) Pešková, IvaTwo strains of Arcobacter butzleri (clinical and environmental isolate) were tested for their ability to grow or survive in cell-free supernatant of Pseudomonas sp. All the pseudomonads tested produced antimicrobial substances against. A. butzleri in agar diffusion assay (King's B medium). Pseudomonas spp. strains exhibited a broad-spectrum antimicrobial activity against both clinical and environmental A. butzleri strains. The growth inhibition ranged from 20 to 60 % compared with that of control at broth assay. The absorbance of cell-free supernatants was determined and peaks characteristic for siderophores (400 nm) were detected. The addition of iron to laboratory medium partly eliminated the inhibitory activity of all pseudomonas strains. These data indicate the involvement of a siderophore(s) in the antimicrobial activity of pseudomonads against A. butzleri.Článek Otevřený přístup peer-reviewedpublished Fall of spherical particles through an Allen-Uhlherr model fluid(Univerzita Pardubice, 2007) Simon, MiloslavIn this work, the numerical solution of Hill's variational principles is presented for the estimation of upper and lower bounds to the drag coefficient correction function necessary for the determination of terminal velocity of spherical particles falling in purely viscous fluids obeying the four-parameter Allen-Uhlherr viscosity model. The calculated data of the drag coeficient correction functions are compared with the available experimental data. In the experiments, terminal falling velocities of spheres in aqueous solutions of polyalkylene glycol Emkarox HV 45 with small addition (0.06.and 0.08% wt) of polyacrylamide Praestol 2935 were measured. At the same time, viscosity function measurements and oscillation dynamic tests of liquids were performed using rheometer RS 150 (Haake). It was found that due to the liquid elasticity the experimental values Xexp of the drag coefficient correction function are beyond the calculated interval of upper and lower bounds and are higher than the upper bounds Xu However, terminal velocities of spheres falling in fluids of the similar type as the test ones can be roughly estimated using the upper bound Xufor determination of a sphere drag coefficient.