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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:
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:
Alanine dosimetry of 60 MeV proton beam - preliminary results
Autorzy:
Michalec, B.
Mierzwińska, G.
Sowa, U.
Ptaszkiewicz, M.
Nowak, T.
Swakoń, J.
Powiązania:
https://bibliotekanauki.pl/articles/146730.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
alanine
dosimetry
electron paramagnetic resonance (EPR)
proton beam
Opis:
Electron paramagnetic resonance (EPR) spectrometry (X-band) was used to determine the dose absorbed in alanine detectors, of different shapes and different alanine content, irradiated with Co-60 gamma rays and in a 60 MeV proton beam. The goal of our study was to confirm applicability of alanine as a passive detector in therapeutic proton beam. In the paper dose response characteristic and relative efficiency of alanine are shown. The study confirmed that alanine detectors with a high alanine content (ca. 95%) may be a useful and convenient tool for dose measurements in proton beams, used for eye cancer treatment.
Źródło:
Nukleonika; 2012, 57, 4; 503-506
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:
Determination of the fraction of paramagnetic centers not-fulfilling the Curie law in coal macerals by the two-temperature EPR measurement method
Autorzy:
Słowik, G. P.
Więckowski, A. B.
Powiązania:
https://bibliotekanauki.pl/articles/146892.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron paramagnetic resonance (EPR)
macerals
two-temperature EPR measurement
Opis:
Two-temperature electron paramagnetic resonance (EPR) measurements, applied to determine the relative contributions of paramagnetic centers – fulfilling and not-fulfilling the Curie law, were carried out. The measurements were made on the macerals – exinite and vitrinite, separated from clarain of the Polish medium- -rank coal (85.6 wt% C). The two-temperature EPR measurements, presented in this work, were performed respectively, at temperatures: T1 = 293 K and T2 = 173 K for exinite, and T1 = 293 K and T2 = 153 K for vitrinite. The relative contributions X of spins not-fulfilling the Curie law present in the studied macerals were calculated. A comparison of different methods of calculating the relative contributions of paramagnetic centers – fulfilling and not-fulfilling the Curie law, present in exinite and vitrinite studied by EPR was made.
Źródło:
Nukleonika; 2015, 60, No. 3, part 1; 389-393
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of microwave power on EPR spectra of DOPA-melanin-netilmicin complexes with different drug concentrations : a study at temperatures in the range of 125-275 K
Autorzy:
Zdybel, M.
Pilawa, B.
Buszman, E.
Wrześniok, D.
Krzyminiewski, R.
Kruczyński, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146482.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DOPA-melanin
electron paramagnetic resonance (EPR) spectroscopy
free radicals
netilmicin
Opis:
Electron paramagnetic resonance (EPR) spectra of the model eumelanin – DOPA-melanin complexes with netilmicin measured with a microwave power in the range 0.3–200 mW were examined. The influence of microwave power on amplitudes (A) and linewidths (ΔBpp) of the spectra was determined. The EPR spectra were recorded by a BRUKER spectrometer at temperatures 125, 175, 225 and 275 K. Continuous microwave saturation of EPR lines was used to compare the acceleration of spin-lattice relaxation processes in melanin samples. Changes of the parameters of the EPR spectra of DOPA-melanin-netilmicin complexes, with the microwave power for the samples differing in netilmicin concentrations, were observed. The effect of temperature on the changes of the EPR spectra of the analyzed melanin complexes with the microwave power was determined. The spin-lattice relaxation is faster at higher temperatures for all the tested melanin complexes.
Źródło:
Nukleonika; 2013, 58, 3; 407-411
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR studies of free radicals in thermally sterilized famotidine
Autorzy:
Ramos, P.
Pilawa, B.
Stroka, E.
Powiązania:
https://bibliotekanauki.pl/articles/148414.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
free radicals
thermal sterilization
famotidine
electron paramagnetic resonance (EPR) spectroscopy
Opis:
Free radicals formation in thermally sterilized famotidine was studied by the use of an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. The influence of temperature and time of sterilization on free radicals generated in famotidine was determined. The best sterilization conditions for the tested drug were found. Sterilization was done according to the pharmaceutical norms at temperatures 160°C (120 min), 170°C (60 min), and 180°C (30 min). It was pointed out that the optimal temperature of thermal sterilization for famotidine was 170°C and time of heating 60 min in this conditions the lowest free radicals concentration was found. The highest free radicals concentration was measured in famotidine heated at 160°C during 120 min, the long time of sterilization is responsible for this effect. Free radicals concentration changes during storage of famotidine after thermal sterilization. Its value increased with storage time for the drug sterilized at both temperatures of 170°C and 180°C. Free radicals concentration decreases from 7 days after sterilization. Complex system of free radicals with the shape of EPR lines, dependent on microwave power exist in thermally sterilized famotidine. Slow spin-lattice relaxation processes, strong dipolar interactions characterize thermally sterilized famotidine. Microwave saturation indicates that EPR lines of famotidine are homogeneously broadened. The usefulness of EPR spectroscopy to examine of the sterilized drugs was evaluated.
Źródło:
Nukleonika; 2013, 58, 3; 413-418
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR measurements of ceramic cores used in the aircraft industry
Autorzy:
Stefaniuk, I.
Rogalska, I..
Potera, P.
Wróbel, D.
Powiązania:
https://bibliotekanauki.pl/articles/148814.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Al2O3
electron paramagnetic resonance (EPR)
mullite
nanopowders
Opis:
In this work the electron paramagnetic resonance (EPR) spectra of Al2O3 and ZrO2 powders were measured for different size of grains (0.074, 0.044 mm) as well as the mullites (0.07 and 0.12 mm). Also were investigated the ceramic cores. The measurements were performed at room temperature and in the temperature range from 140 up to 380 K. The main purpose of this work was to investigate the possible relationships between the EPR spectra and the size of powder grains as well as the identification of EPR spectra in view of the potential application of EPR technique as a fingerprinting method.
Źródło:
Nukleonika; 2013, 58, 3; 391-395
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Localized states in nanocarbons
Autorzy:
Kempiński, W.
Kempiński, M.
Markowski, D.
Łoś, M.
Powiązania:
https://bibliotekanauki.pl/articles/148234.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
activated carbon fibers (ACF)
carbon nanotubes
electron paramagnetic resonance (EPR)
fullerenes
Opis:
Localization phenomenon is studied in different modern nanocarbon materials: pristine C60, C60-fullerides, carbon nanotubes and graphene-based structures in the form of activated carbon fibers built of quantum dot-like basic structural units. Two experimental methods are used to define the localization and population control of spins (charge carriers) in the nanocarbon materials – electron paramagnetic resonance (EPR) and direct current (d.c.) electrical conductivity measurements. Results are discussed in the frame of the possible applications of the aforementioned materials in the molecular electronics or spintronics.
Źródło:
Nukleonika; 2013, 58, 3; 371-373
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interaction of diatomic molecules with nickel ions inside the channels of high silica zeolites : an EPR and DFT study
Autorzy:
Mazur, T.
Podolska, K.
Pietrzyk, P.
Sojka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/147105.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron paramagnetic resonance (EPR) spectroscopy
g-tensor
nickel
zeolite
small molecule activation
Opis:
Interaction of CO, NO, and O2 diatomics with NiII and NiI ions dispersed in ZSM-5 zeolite was investigated by electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) modelling. The resulting adducts NiI-CO, NiII-NO, and NiI-O2 were identified based on g-tensor parameters, obtained by computer fitting of the powder EPR spectra, and next ascertained by parallel relativistic DFT calculations of the corresponding g-tensor values. The structures of the NiI-CO, NiII-NO, and NiI-O2 complexes were obtained by geometry optimization with the Kohn- -Sham method. Binding of the diatomics was discussed in terms of the spin-pairing and electron density transfer events. Interaction of CO with NiI cations led to the pronounced change in the coordination and electronic structure of the NiI center, however, no redox processes were observed in agreement with the “innocent” nature of CO as a ligand. On the contrary, strong electron and spin density redistribution was observed upon NO and O2 interaction (“non-innocent ligands”) leading to the formation of the bound nitrosonium NOδ+ and superoxo O2 – species, respectively.
Źródło:
Nukleonika; 2013, 58, 3; 351-357
0029-5922
1508-5791
Pojawia się w:
Nukleonika
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 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:
EPR studies of Cladosporium cladosporioides complexes with amphotericin B
Autorzy:
Zdybel, M.
Pilawa, B.
Buszman, E.
Witoszyńska, T.
Powiązania:
https://bibliotekanauki.pl/articles/147790.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
amphotericin B
Cladosporium cladosporioides
electron paramagnetic resonance (EPR) spectroscopy
free radicals
melanin
Opis:
Free radicals in Cladosporium cladosporioides cultured with amphotericin B were spectroscopically studied. The effect of drug concentrations on free radicals in the fungal melanin biopolymer was examined. It was pointed out that the concentrations of free radicals in the complexes of Cladosporium cladosporioides mycelium with amphotericin B depend on the drug concentrations. Eumelanin dominates in the fungal studied samples. The slow spin-lattice relaxation processes exist in the tested samples. Free radicals take a part in the formation of Cladosporium cladosporioides mycelium complexes with amphotericin B.
Źródło:
Nukleonika; 2013, 58, 3; 401-405
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:
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
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