Temat: 61.66.Hq - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Effect of pH on Paramagnetic Centers in Cladosporium cladosporioides Melanin
Autorzy:: Pilawa, B.
Buszman, E.
Gondzik, A.
Wilczyński, S.
Zdybel, M.
Witoszyńska, T.
Wilczok, T.
Powiązania:: https://bibliotekanauki.pl/articles/2043413.pdf
Data publikacji:: 2005-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
Opis:: Paramagnetic centers in melanin existing in pigmented soil fungi Cladosporium cladosporioides cultured at acidic (4, 5, 6), neutral (7), and alkaline (8) pH were studied by EPR method. o-semiquinone free radicals (g: 2.0032-2.0040) concentration in melanin biopolymer increased for pH from 4 to 6, decreased at pH 7, and reached the maximum value at pH 8. It may be expected that melanin free radicals reactions with small molecules (metal ions, drugs) are the most effective at pH between 6 and 8. Slow spin-lattice relaxation processes exist in the all studied melanin samples.
Źródło:: Acta Physica Polonica A; 2005, 108, 1; 147-150
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Paramagnetic Centers in DOPA-Melanin-Dihydrostreptomycin Complexes
Autorzy:: Buszman, E.
Pilawa, B.
Zdybel, M.
Wrześniok, D.
Grzegorczyk, A.
Wilczok, T.
Powiązania:: https://bibliotekanauki.pl/articles/2043624.pdf
Data publikacji:: 2005-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
Opis:: DOPA-melanin-dihydrostreptomycin complexes with drug concentrations 1×10$\text{}^{-4}$-1×10$\text{}^{-2}$ M were examined by the use of electron paramagnetic resonance spectroscopy at X-band (9.3 GHz). Dihydrostreptomycin was chosen for studies, because this aminoglycoside antibiotic causes strong toxic effects in organism. It was stated that dihydrostreptomycin generates o-semiquinone free radicals with g=2.0038 in melanin. Free radicals formation increases with increase in the antibiotic concentration. Changes of EPR lines with microwave powers pointed out that slow spin-lattice relaxation processes exist in DOPA-melanin and in its complexes with dihydrostreptomycin. The measured EPR lines were homogeneously broadened.
Źródło:: Acta Physica Polonica A; 2005, 108, 2; 353-356
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Multi-Component EPR Spectra of Coals with Different Carbon Content
Autorzy:: Pilawa, B.
Więckowski, A. B.
Pietrzak, R.
Wachowska, H.
Powiązania:: https://bibliotekanauki.pl/articles/2043651.pdf
Data publikacji:: 2005-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
Opis:: EPR spectra of lignite"Mequinenza" (Spain) (62.3 wt% C) and Polish orthocoking coal (87.8 wt% C) were compared. The spectra were superpositions of broad Gaussian, broad Lorentzian 1, and narrow Lorentzian 3 lines. Concentration of paramagnetic centers - mainly delocalizedπ electrons - responsible for narrow Lorentzian 3 lines increases with increase in carbon content in coal. Coal units with slow and fast spin-lattice relaxation processes exist in the two studied samples. Slow spin-lattice interactions occur in simple aromatic coal units with broad Gaussian and Lorentzian 1 lines. Fast spin-lattice relaxation processes are characteristic of large aromatic units with narrow Lorentzian 3 lines.
Źródło:: Acta Physica Polonica A; 2005, 108, 2; 403-407
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: EPR Studies of Carbonized Cellulose - Oxygen Interactions
Autorzy:: Pilawa, B.
Pietrzak, R.
Wachowska, H.
Babeł, K.
Powiązania:: https://bibliotekanauki.pl/articles/2043418.pdf
Data publikacji:: 2005-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
Opis:: EPR examination of cellulose carbonized at 400ºC and 600ºC has been performed. The aim of this work was to search a sample useful as the oximetric probe in biology and medicine. The higher paramagnetic centers concentration characterizes cellulose carbonized at 600ºC, which was found as the sensitive oximetric probe. Quasi-chemical bonds between cellulose molecules and paramagnetic O$\text{}_{2}$ molecules decrease paramagnetic centers concentration. A linear increase in paramagnetic centers concentration and a linear decrease in EPR linewidth with increasing time of sample evacuation were observed for cellulose carbonized at 600ºC. Oxygen affects spin-lattice interactions in carbonized cellulose.
Źródło:: Acta Physica Polonica A; 2005, 108, 1; 151-154
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Triplet States in DOPA-Melanin and in Its Complexes with Kanamycin and Copper Cu(II) Ions
Autorzy:: Najder-Kozdrowska, L.
Pilawa, B.
Buszman, E.
Więckowski, A.
Świątkowska, L.
Wrześniok, D.
Wojtowicz, W.
Powiązania:: https://bibliotekanauki.pl/articles/1535688.pdf
Data publikacji:: 2010-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
87.64.kh
Opis:: The mono- and biradical forms of DOPA-melanin (DOPA-eumelanin) were studied by EPR spectroscopy in 100-300 K temperature range. The existence of triplet states in DOPA-melanin was proved. The analysis of EPR spectra has shown that in DOPA-melanin and its complexes with kanamycin and $Cu^{2+}$ ions, two kinds of paramagnetic centres exist. The first of them are in doublet ground state with spin S = 1/2 and they obey the Curie law. The paramagnetic centres of the second group are in thermally excited triplet state with spin S = 1 and in this case the Curie law is not fulfilled.
Źródło:: Acta Physica Polonica A; 2010, 118, 4; 613-618
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 6.

Tytuł:: Groups of Paramagnetic Centres in Reduced and Methylated Low Rank Coal
Autorzy:: Pilawa, B.
Wachowska, H.
Kozłowski, M.
Więckowski, A.
Najder-Kozdrowska, L.
Powiązania:: https://bibliotekanauki.pl/articles/1401865.pdf
Data publikacji:: 2015-09
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 33.35.+r
61.66.Hq
76.30.-v
76.30.Rn
89.30.ag
Opis:: Low rank Illinois No. 6 coal was studied by electron paramagnetic resonance EPR spectroscopy. The parameters of EPR spectra (spectroscopic splitting factors g, linewidths $\DeltaB_{pp}$, concentrations of paramagnetic centres N) were measured for row and chemically treated coal (demineralized, reduced and methylated samples). The multi-component structure of experimental spectra of this coal was proved. Two groups of paramagnetic centres responsible for broad Lorentzian 1 and narrow Lorentzian 2 lines exist in studied samples. Paramagnetic centres connected with component lines revealed different behaviour during chemical treatments.
Źródło:: Acta Physica Polonica A; 2015, 128, 3; 264-267
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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