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Wyszukujesz frazę "paramagnetic centers" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Effect of microwave power on EPR spectra of natural and synthetic dental biocompatible materials
Autorzy:
Adamczyk, J.
Ramos, P.
Pilawa, B.
Powiązania:
https://bibliotekanauki.pl/articles/147235.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
EPR
microwave saturation
paramagnetic centers
dental biocompatible materials
Opis:
Paramagnetic centers in the two exemplary synthetic and natural dental biocompatible materials applied in implantology were examined by the use of an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra were measured in the range of microwave power 2.2–70 mW. The aims of this work were to compare paramagnetic centers concentrations in different dental biocompatible materials and to determine the effect of microwave power on parameters of their EPR spectra. It is the very fi rst and innovatory examination of paramagnetic centers in these materials. It was pointed out that paramagnetic centers existed in both natural (~1018 spin/g) and synthetic (~1019 spin/g) dental biocompatible materials, but the lower free radical concentration characterized the natural sample. Continuous microwave saturation of EPR spectra indicated that faster spin-lattice relaxation processes existed in synthetic dental biocompatible materials than in natural material. Linewidths (ΔBpp) of the EPR spectra of the natural dental material slightly increased for the higher microwave powers. Such effect was not observed for the synthetic material. The broad EPR lines (ΔBpp): 2.4 mT, 3.9 mT, were measured for the natural and synthetic dental materials, respectively. Probably strong dipolar interactions between paramagnetic centers in the studied samples may be responsible for their line broadening. EPR spectroscopy is the useful experimental method in the examination of paramagnetic centers in dental biocompatible materials.
Źródło:
Nukleonika; 2015, 60, No. 3, part 1; 449-453
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conditions of photodynamic therapy of tumor cells examined by carbonized coal and EPR spectroscopy
Autorzy:
Latocha, M.
Pilawa, B.
Pietrzak, R.
Nowicki, P.
Wachowska, H.
Powiązania:
https://bibliotekanauki.pl/articles/284850.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
centra paramagnetyczne
PDT
próby oksymetryczne
EPR
paramagnetic centers
oximetric probes
Opis:
Coal samples carbonized at 600°C and TEMPO probes we applied in oximetry. EPR spectra of medium-ranked coal carbonized at 400, 500, and 700 °C were not sensitive to oxygen. Oxygen effects during photodynamic therapy of tumor cells were tested. Oximetric probes were used to examination of singlet oxygen O2 formation in melanotic CRL-1424 tumor cells irradiated by laser (500 mW, Λ = 662 nm) at the presence of photolon as the photosensitizer. Tumor cells were irradiated during 7, 15, and 30 minutes. Changes in EPR spectra of coal probe and TEMPO after excitation of oxygen O2 from triplet ground state (S=1) to diamagnetic singlet (S=0) state were analysed. Measurements of EPR spectra of coal carbonized at 60O°C and TEMPO in: control cell culture, irradiated cells, and cells irradiated at the presence of photolon, were done. After PDT intensity of EPR lines of the used oximetric probes considerably increases. It was proved that the strongest formation of singlet oxygen in the studied cells appears after 15 minutes of laser irradiation.
Źródło:
Engineering of Biomaterials; 2008, 11, 73; 6-8
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of oxygen O2 on microwave saturation of EPR lines of plants carbonized at 650°c and potential application in medicine
Autorzy:
Pilawa, B.
Bartłomiejczyk, S.
Krzesińska, M.
Pusz, S.
Zachariasz, J.
Wałach, W.
Powiązania:
https://bibliotekanauki.pl/articles/284844.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
karbonizacja roślin
elektroniczny rezonans paramagnetyczny
EPR
nasycenie mikrofalowe
centra paramagnetyczne
oksymetria
carbonized plants
electron paramagnetic resonance
microwave saturation
paramagnetic centers
oximetry
Opis:
Electron paramagnetic resonance spectroscopy (EPR) was used to examination of spin-lattice relaxation in vascular plants carbonized at 650°C. Application of EPR method of continuous microwave signal saturation in medicine was proposed. The first derivative EPR spectra of pyrolysed bamboo and yucca were measured for samples in air and in vacuum. Influence of microwave power in the range 0.7-100 mW on amplitudes of EPR lines were evaluated. It was stated that amplitudes of the studied carbon materials increase with increasing of microwave power in the studied range. Saturation of EPR lines was not observed, so fast spin-lattice relaxation processes exist in the analyzed materials. Changes of EPR amplitudes for samples in air were slower than for evacuated samples. This effect may be used for determination of oxygen contents in the biological cells cultures and for analysis of optimal parameters of photodynamic therapy of cancer.
Źródło:
Engineering of Biomaterials; 2008, 11, 73; 9-11
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparatwe EPR analysis of oxygen interactions with plants carbonized at different temperatures
Autorzy:
Bartłomiejczyk, S.
Pilawa, B.
Krzesińska, M.
Pusz, S.
Zachariasz, J.
Wałach, W.
Powiązania:
https://bibliotekanauki.pl/articles/284848.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
karbonizacja roślin
centra paramagnetyczne
paramagnetyczne utlenianie cząsteczek
elektroniczny rezonans paramagnetyczny
widma EPR
oksymetria
carbonized plants
paramagnetic centers
paramagnetic oxygen molecules
electron paramagnetic resonance
EPR spectra
oximetry
Opis:
Carbon materials, bamboo (Bambusa vulagris) and yucca (Yucca flaccida) pyrolysed at 550°C, 750°C and 950°C, were tested as oximetric probes by electron paramagnetic resonance spectroscopy at X-band (9.3 GHz). The following parameters of the spectra: amplitude, linewidth and g-factor, were determined. Influence of oxygen molecules 02 on EPR spectra of the individual carbon materials was compared. Strong EPR spectra were recorded for samples carbonized at 550°C and weak signals were obtained for plants carbonized at higher temperatures: 750°C and 950°C. It was stated that amplitudes of EPR lines of all the carbonized plants decrease in the air environment compared to amplitudes of spectra measured in vacuum. This effect increases with degree of vacuum. Changes in the EPR spectra of samples studied in the air environment may be applied in medicine to determination of oxygen content in different cells. Because of strong resonance signals as oximetric probes we proposed bamboo and yucca carbonized at 550°C, and we rejected plants carbonized at 750°C and 950°C with Iow EPR signals.
Źródło:
Engineering of Biomaterials; 2008, 11, 73; 3-5
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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