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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
Tytuł:
Electron paramagnetic resonance (EPR) study of the short - living radicals generated thermally in phosphorylated maize starch with different amounts of amylose
Autorzy:
Bidzińska, E.
Dyrek, K.
Kruczała, K.
Szczygieł, J.
Wenda, E.
Błaszczak, W.
Fornal, J.
Powiązania:
https://bibliotekanauki.pl/articles/147482.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
carbon centred radicals
electron paramagnetic resonance (EPR) spectroscopy
PBN spin trap
starch phosphates
thermal treatment
Opis:
Quantitative electron paramagnetic resonance (EPR) spectroscopy was used for the determination of a number and properties of short-living radicals generated thermally in maize starch with various amounts of amylose. The EPR spectra of radical adducts with N-tert-butyl-α-phenylnitrone (PBN) spin trap reveal the presence of three types of radicals of mobility related with their localization in the zones of various degree of crystallinity. Hylon VII, which represents a matrix with a high content of amylose, offers better conditions for free rotation of radical species, whereas waxy maize, containing almost exclusively amylopectin, exhibits more restricted dynamics.
Źródło:
Nukleonika; 2013, 58, 3; 429-433
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR study of ZnO:Co thin films grown by the PLD method
Autorzy:
Cieniek, B.
Stefaniuk, I.
Virt, I.
Powiązania:
https://bibliotekanauki.pl/articles/146744.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron paramagnetic resonance (EPR)
diluted magnetic semiconductor (DMS)
ZnO:Co
Curie temperature
Opis:
We have studied magnetic properties of zinc-oxide composite doped with a relatively high concentration (4%) of Co ions. Samples were obtained by the pulsed laser deposition (PLD) method with different parameters of the laser ablation. For various samples, the power of laser was changed as well as the temperature of sample heating. Electron paramagnetic resonance (EPR) measurements were carried out and temperature dependence of the EPR spectra was obtained. Analysis of the temperature dependences of the integral intensity of EPR spectra was carried out using the Curie-Weiss law. Fitting yields the following values θCW = 150 K and C = 1.6710, where C is the Curie constant, and θCW is the paramagnetic Curie temperature.
Źródło:
Nukleonika; 2013, 58, 3; 359-363
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Attaching a spin to a protein - site-directed spin labeling in structural biology
Autorzy:
Czogalla, Aleksander
Pieciul, Aldona
Jezierski, Adam
Sikorski, Aleksander
Powiązania:
https://bibliotekanauki.pl/articles/1041067.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
protein structure
site-directed spin labeling
electron paramagnetic resonance (EPR) spectroscopy
Opis:
Site-directed spin labeling and electron paramagnetic resonance spectroscopy have recently experienced an outburst of multiple applications in protein science. Numerous interesting strategies have been introduced for determining the structure of proteins and its conformational changes at the level of the backbone fold. Moreover, considerable technical development in the field makes the technique an attractive approach for the study of structure and dynamics of membrane proteins and large biological complexes at physiological conditions. This review focuses on a brief description of site-directed spin labeling-derived techniques in the context of their recent applications.
Źródło:
Acta Biochimica Polonica; 2007, 54, 2; 235-244
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Copper-manganese-zinc spinels in zeolites : study of EMR spectra
Autorzy:
Decyk, P.
Więckowski, A. B.
Najder-Kozdrowska, L.
Bilkova, I.
Powiązania:
https://bibliotekanauki.pl/articles/146776.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Cu-Mn-Zn spinels
electron magnetic resonance
paramagnetic complexes
Y zeolites
Opis:
The aim of this study is the application of electron magnetic resonance (EMR) spectroscopy to determine the interactions between NaY and HY zeolites and Cu-Mn-Zn spinels loaded onto the zeolite surfaces. The materials were characterized using XRD and IR spectroscopies. Four types of EMR lines were observed for Cu-Mn-Zn/NaY, Cu-Mn-Zn/HY samples. The difference between the EMR spectra recorded at 77 and 293 K has been shown. The spectra recorded at 77 K allowed us to distinguish between the species formed on NaY and HY zeolites. The EMR spectrum of Cu-Mn-Zn/NaY recorded at 77 K showed only one line attributed to antiferromagnetic spinels Cu1.4Mn1.6O4 and ZnMn2O4 or/and Cu0.5Zn0.5Mn2O4. The spinels appeared to be more stable (more strongly attached) on HY zeolite than on NaY one. It was proved that different strength of interactions between the zeolites and Cu-Mn-Zn spinels was caused by differences in the acidity of NaY and HY zeolites.
Źródło:
Nukleonika; 2015, 60, No. 3, part 1; 423-428
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron paramagnetic resonance [EPR] investigations of laser induced free radicals in spring wheat grains
Autorzy:
Drozd, D.
Szajner, H.
Jezierski, A.
Powiązania:
https://bibliotekanauki.pl/articles/25812.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
spring wheat
wheat grain
laser
electron paramagnetic resonance
free radical
Źródło:
International Agrophysics; 1999, 13, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR spectroscopy of Cu2+ and Mn2+ in borate glasses
Autorzy:
Drzewiecki, A.
Padlyak, B.
Adamiv, V.
Burak, Y.
Teslyuk, I.
Powiązania:
https://bibliotekanauki.pl/articles/147654.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
borate glasses
Cu2+ paramagnetic centre
electron paramagnetic resonance (EPR) spectroscopy
hyperfine structure
Mn2+ paramagnetic centre
Opis:
Electron paramagnetic resonance (EPR) spectra of the CaB4O7 and LiCaBO3 glasses containing 0.5 and 1.0 mol.% CuO and MnO2 impurity compounds were investigated at room temperature. The glasses with CaB4O7:Cu, LiCaBO3:Cu, CaB4O7:Mn and LiCaBO3:Mn compositions were produced from the corresponding polycrystalline compounds using standard glass synthesis and technological conditions developed by the authors. The EPR spectral parameters of the Cu2+ and Mn2+ centres in both glasses containing 0.5 and 1.0 mol.% CuO and MnO2 doping oxides were determined. Analysis of EPR spectral parameters shows that Cu impurity is incorporated into the CaB4O7 and LiCaBO3 glass network as isolated Cu2+ (3d9, 2D5/2) paramagnetic ions. The Cu2+ ions occupy Ca(Li) sites of the borate glass network coordinated by six O2− anions with geometry of elongated octahedron (D4h symmetry) due to the Jahn- -Teller effect. The EPR spectra of the Mn-doped CaB4O7 and LiCaBO3 glasses are virtually identical and typical of all oxide glasses activated with Mn2+ (3d5, 6S5/2) ions. Observed EPR spectra in the Mn-doped glasses were attributed to isolated Mn2+ (1) centres (geff ≅ 4.3) in octahedral Ca(Li) sites with a strong (fully) rhombic distortion, isolated Mn2+ (2) centres (geff ≅ 2.0) in octahedral Ca(Li) sites with nearly cubic local symmetry as well as pairs and small clusters of the Mn2+ ions, coupled by magnetic dipolar and exchange interactions. On the basis of the obtained results and analysis of referenced data, the local structure of the Cu2+ and Mn2+ centres in the borate glasses have been proposed.
Źródło:
Nukleonika; 2013, 58, 3; 379-385
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bloch - Siegert shift in the Rabi oscillations on the “dressed” electron spin states
Autorzy:
Fedaruk, R.
Kolasa, A.
Saiko, A. P.
Powiązania:
https://bibliotekanauki.pl/articles/146386.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron paramagnetic resonance (EPR)
Bloch-Siegert shift
Rabi oscillation
bichromatic field
dressed state
spin qubit
Opis:
Using electron paramagnetic resonance (EPR) at Rabi frequencies, we study the Bloch-Siegert effect in the coherent dynamics of electron spin states driven by a bichromatic radiation consisting of a transverse microwave (MW) and longitudinal radio frequency (RF) fields. The Rabi oscillations on the electron spin states “dressed” by the MW field are observed at the double resonance, when the MW frequency equals the Larmor frequency of the spin system and the frequency ωrf of the RF field is close to the Rabi frequency ω1 in the MW field. The dispersive (|ωrf – ω1| ~ ωrf, ω1) and near-resonant (ωrf ≈ ω1) regimes are investigated. We demonstrate that the Bloch-Siegert shift increases with increasing RF amplitude and at the fixed RF amplitude it has the largest values in the “low-frequency” (ωrf < ω1) range of the dispersive regime. Experimental results were obtained in the time-resolved EPR for E’1 centres in quartz.
Źródło:
Nukleonika; 2013, 58, 3; 375-378
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In vitro effects of ozone on human erythrocyte membranes: An EPR study
Autorzy:
Górnicki, Albert
Gutsze, Aleksander
Powiązania:
https://bibliotekanauki.pl/articles/1044218.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
spin labelling
erythrocyte membrane fluidity
electron paramagnetic resonance
medical ozone
Opis:
The effects of ozone at different concentrations (10, 30, 45 g/m3) on fluidity and thermotropic properties of erythrocyte membranes were investigated by EPR using two spin probes: 5-doxylstearic acid (5-DSA) and 16-doxylstearic acid (16-DSA). The effect of ozone on the erythrocyte membrane fluidity was a dose-dependent process. The ozone at concentration of 10 g/m3 caused rigidization of the membrane while at concentration of 45 g/m3 increased fluidity both on the surface and in the deeper hydrocarbon region of the membrane. Temperature transitions close to the polar heads region (monitored by 5-DSA) were not sensitive to an increase in ozone concentration. In the case of 16-DSA, low temperature thermotropic transition (around 20°C) gradually decreased with the increase of ozone concentration. High temperature transition (around 40°C) significantly differed at the ozone concentration of 10 g/m3 and 45 g/m3, being higher and lower, respectively, as compared to untreated cells. For the ozone concentration of 45 g/m3 the disappearance of the low temperature break and the appearance of two breaks at 37°C and 16°C were observed.
Źródło:
Acta Biochimica Polonica; 2000, 47, 4; 963-971
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR study of guanidine zinc sulphate crystals
Autorzy:
Gruszka, K.
Hrabański, R.
Ozga, J.
Czapla, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146384.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron paramagnetic resonance (EPR)
zero-field splitting (ZFS)
transition ions in crystals
Opis:
X-band electron paramagnetic resonance (EPR) investigations of Mn2+-doped guanidine zinc sulphate [C(NH2)3]2Zn(SO4)2 – abbreviated as GZS – are presented. The EPR spectrum in the temperature range 273–393 K exhibits a group of five fine structure transitions each splits into six hyperfine components. The angular variation of EPR spectra reveals the presence of only one magnetic complex, which correspond to one distinct site of Mn2+ ions in the crystal lattice. From the observed EPR spectrum, the spin-Hamiltonian parameters have been evaluated. The variation of zero-field splitting (ZFS) parameter, intensity and line width with temperature are measured and discussed.
Źródło:
Nukleonika; 2013, 58, 3; 387-390
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR study on sugar radicals utilized for detection of radiation treatment of food
Autorzy:
Guzik, G. P.
Stachowicz, W.
Michalik, J.
Powiązania:
https://bibliotekanauki.pl/articles/146706.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
density functional theory (DFT)
dried fruits
electron paramagnetic resonance (EPR)
irradiation
mannose
sorbose
Opis:
Radicals produced by ionizing radiation in sugars, the components of dried and raw fruits give rise to stable multicomponent electron paramagnetic resonance (EPR) signals unidentified so far. The subject of the present EPR study is to identify the radicals stabilized in gamma-irradiated crystalline sugars, D(+)mannose and L(-)sorbose extracted from cranberries (Vaccininum oxycoccos) and rowan berries (Sorbus aucuparia), respectively. EPR measurements and density functional theory (DFT) simulations were employed for that purpose.
Źródło:
Nukleonika; 2012, 57, 4; 545-549
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of irradiated dried fruits using EPR spectroscopy
Autorzy:
Guzik, G. P.
Stachowicz, W.
Michalik, J.
Powiązania:
https://bibliotekanauki.pl/articles/148844.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dried fruits
electron paramagnetic resonance (EPR)
fructose
glucose
irradiation
Opis:
The dominating carbohydrates in fruits are monosaccharides like fructose, glucose, sorbose and mannose. In dehydrated fruits, concentration of monosaccharides is higher than in fresh fruits resulting in the formation of sugar crystallites. In most of dried fruits, crystalline fructose, and glucose dominate and appear in proportion near to 1:1. Irradiation of dried fruits stimulates radiation chemical processes resulting in the formation of new chemical products and free radicals giving rise to multicomponent EPR signal which can be detected for a long period of time. For that reason, it is used as a marker for the detection of radiation treatment of dried fruits. It has been found that EPR spectra recorded in dried banana, pineapple, papaya, and fig samples resemble the EPR spectrum obtained by computer addition of fructose and glucose spectra taken in proportion 1:1. The decay of radiation induced EPR signals proceeds in dried fruits fast during the first month of observation and becomes much slower and almost negligible after prolonged storage. However, it remains intense enough for EPR detection even one year after processing. The radiation induced EPR signal is easily detected in dried fruits exposed to 0.5 kGy of gamma rays. Thus, the EPR method of the detection of irradiated fruits can be used for the control of dried fruits undergoing quarantine treatment with 200–300 Gy of ionizing radiation.
Źródło:
Nukleonika; 2015, 60, No. 3, part 2; 627-631
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on radiation-induced radicals giving rise to stable EPR signal suitable for the detection of irradiation in L-sorbose-containing fruits
Autorzy:
Guzik, G. P.
Stachowicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/146498.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
sorbose
crystallite
electron paramagnetic resonance (EPR)
EPR
irradiation
Opis:
The stable and complex EPR signals produced by the action of ionizing radiation on crystalline L-sorbose (C6H12O6) separated from rowan berries (Sorbus aucuparia) were studied. Isothermal heating of the samples at the temperature close to the melting point of L-sorbose (140°C) results in the modification and simplification of the EPR signal involved. In the EPR signal of heated L-sorbose, the isotropic quartet was distinguished. In the differential spectrum obtained by subtraction of normalized spectra of unheated and heated L-sorbose, the isotropic doublet was identified in addition. The DFT fitting offers the probable assignment of the EPR signals to specifi c radical structures.
Źródło:
Nukleonika; 2016, 61, 4; 461-465
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on irradiated D-mannose isolated from cranberry
Autorzy:
Guzik, Grzegorz P.
Stachowicz, Wacław
Michalik, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/147508.pdf
Data publikacji:
2019
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
crystallite
electron paramagnetic resonance
EPR
irradiation
mannose
Opis:
The stable EPR signal produced by ionizing radiation in crystalline D-mannose (C6H12O6) and separated from cranberries (Vaccinium oxycoccus) was studied. The isothermal heating of irradiated sample at 95°C for 10 minutes (melting point of D-mannose is 132°C) resulted in the modifi cation and simplifi cation of the EPR signal involved. The isotropic quartet has been recognized in the EPR signal of heat-treated sample. Molecular structure of the isotropic quartet identifi ed in the complex EPR signal of D-mannose crystallite is proposed.
Źródło:
Nukleonika; 2019, 64, 4; 139-143
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Microwave Sources for EPR Spectroscopy
Autorzy:
Hruszowiec, M.
Nowak, K.
Szlachetko, B.
Grzelczak, M.
Czarczyński, W.
Pliński, E. F.
Więckowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/308886.pdf
Data publikacji:
2017
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
electron paramagnetic resonance
gyrotron EPR
microwave sources
orotron
terahertz waves
Opis:
Rapid development of many scientific and technical disciplines, especially in material science and material engineering increases a demand for quick, accurate and cheap techniques of materials investigations. The EPR spectroscopy meets these requirements and it is used in many fields of science including biology, chemistry and physics. For proper work, the EPR spectrometer needs a microwave source, which are reviewed in this paper. Vacuum tubes as well as semiconductor generators are presented such as magnetron, klystron, traveling wave tube, backward wave oscillator, orotron, gyrotron, Gunn and IMPATT diodes. In this paper main advantages of gyrotron usage, such as stability and an increased spectral resolution in application to EPR spectroscopy is discussed. The most promising and reliable microwave source is suggested.
Źródło:
Journal of Telecommunications and Information Technology; 2017, 2; 18-25
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 35

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