Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 4

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  radicals
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Free radicals in a conglomerate of peripheral blood with a spin trap investigated by the EPR method before and after angioplasty treatment

100%
Krzyminiewski R., Kruczynski Z., Stepien A., Dobosz B.
Polish Journal of Medical Physics And Engineering
|
2008
|
vol. 14
|
issue 1
1-12
EN
The Electron Paramagnetic Resonance (EPR) was used to investigate free radicals in the peripheral blood of patients subjected to angioplasty treatment. To detect these free radicals, a nitrosobenzene spin trap was used in this experiment. The EPR spectra of the blood with a spin trap conglomerate was measured at room temperature and at 170 K. To confirm the kind of free radicals in the conglomerate blood-spin trap, simulation and quantum-chemical calculations were made, and the conglomerate spin trap with ascorbic acid was measured. Two different types of radicals, one at room temperature and the other in a frozen sample of blood, were found.
2
Content available remote

Sterilization of bacteria suspensions and identification of radicals deposited during plasma treatment

88%
Puač N., Miletić M., Mojović M., Popović-Bijelić A., Vuković D., Miličić B., Maletić D., Lazović S., Malović G., Petrović Z. L.
Open Chemistry
|
2015
|
vol. 13
|
issue 1
EN
In this paper we will present results for plasma sterilization of planktonic samples of two reference strains of bacteria, Pseudomonas aeruginosa ATCC 27853 and Enterococcus faecalis ATCC 29212. We have used a plasma needle as a source of non-equilibrium atmospheric plasma in all treatments. This device is already well characterized by OES, derivative probes and mass spectrometry. It was shown that power delivered to the plasma is bellow 2 W and that it produces the main radical oxygen and nitrogen species believed to be responsible for the sterilization process. Here we will only present results obtained by electron paramagnetic resonance which was used to detect the OH, H and NO species. Treatment time and power delivered to the plasma were found to have the strongest influence on sterilization. In all cases we have observed a reduction of several orders of magnitude in the concentration of bacteria and for the longest treatment time complete eradication. A more efficient sterilization was achieved in the case of gram negative bacteria.
3
Content available remote

Multifrequency EPR study on radiation induced centers in calcium carbonates labeled with13C

75%
Sadło J., Bugaj A., Strzelczak G., Sterniczuk M., Jaegermann Z.
|
|
issue 3
429-434
EN
In calcite and aragonite, γ-irradiated at 77 K, several paramagnetic centers were generated and detected by EPR spectroscopy; in calcite, CO3− (orthorhombic symmetry, bulk and bonded to surface), CO33−, NO32−, O3−, and in aragonite CO2− (isotropic and orthorhombic symmetry) depending on the type of calcium carbonate used. For calcium carbonates enriched with 13C more detailed information about the formed radicals was possible to be obtained. In both natural (white coral) and synthetic aragonite the same radicals were identified with main differences in the properties of CO2− radicals. An application of Q-band EPR allowed to avoid the signals overlap giving the characteristics of radical anisotropy.
4
Content available remote

The acid-catalyzed interaction of melanin with nitrite ions. An EPR investigation

75%
Matuszak Z., Chignell C. F., Reszka K. J.
|
|
issue 3
475-481
EN
The interaction of synthetic dihydroxyphenylalanine (DOPA) melanin (DM) with nitrite ions, NO2−, in the pH 3.6–7.0 range, has been investigated using electron paramagnetic resonance (EPR). We found that especially at pH <5.5 (from ca. 5.5 to 3.6) the reaction of DM with nitrite generated large quantities of new melanin radicals, which implies the involvement of nitrous acid, HNO2, in the radical formation process. Measurements carried out at constant pH of 3.6 showed that the melanin signal increased together with nitrite concentration, reaching a plateau level which was more than fourfold larger compared to the initial signal amplitude observed in a nitrite-free buffer of the same pH. The effects of nitrite and DM concentrations on the melanin-free radical content were also investigated. It is proposed that the radicals are generated by one electron oxidation of melanin ortho-hydroquinone groups to ortho-semiquinones by HNO2 or related nitrogen oxides such as NO2• radicals. The possible involvement of nitric oxide (•NO) and peroxynitrite (ONOO−) in DM oxidation was also examined. In air-free solutions, nitric oxide per se did not generate melanin radicals; however, in the presence of oxygen a marked increase in the melanin EPR signal intensity was observed. This result is interpreted in terms of the generation of radicals via the oxidation of DM by peroxynitrite. Our findings suggest that melanin can function as a natural scavenger of nitrous acid and some nitrous acid-derived species. This property may be relevant to physiological functions of melanin pigments in vivo.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.