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    Wyświetlanie 1-35 z 35
    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:
    Mitochondria recycle nitrite back to the bioregulator nitric monoxide.
    Autorzy:
    Nohl, Hans
    Staniek, Katrin
    Sobhian, Babak
    Bahrami, Soheyl
    Redl, Heinz
    Kozlov, Andrey
    Powiązania:
    https://bibliotekanauki.pl/articles/1044210.pdf
    Data publikacji:
    2000
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    nitrite reductase
    electron paramagnetic resonance
    nitric oxide
    mitochondria
    Opis:
    Nitric monoxide (NO) exerts a great variety of physiological functions. L-Arginine supplies amino groups which are transformed to NO in various NO-synthase-active isoenzyme complexes. NO-synthesis is stimulated under various conditions increasing the tissue of stable NO-metabolites. The major oxidation product found is nitrite. Elevated nitrite levels were reported to exist in a variety of diseases including HIV, reperfusion injury and hypovolemic shock. Denitrifying bacteria such as Paracoccus denitrificans have a membrane bound set of cytochromes (cyt cd1, cyt bc) which were shown to be involved in nitrite reduction activities. Mammalian mitochondria have similar cytochromes which form part of the respiratory chain. Like in bacteria quinols are used as reductants of these types of cytochromes. The observation of one-e- divergence from this redox-couple to external dioxygen made us to study whether this site of the respiratory chain may also recycle nitrite back to its bioactive form NO. Thus, the aim of the present study was therefore to confirm the existence of a reductive pathway which reestablishes the existence of the bioregulator NO from its main metabolite NO2-. Our results show that respiring mitochondria readily reduce added nitrite to NO which was made visible by nitrosylation of deoxyhemoglobin. The adduct gives characteristic triplet-ESR-signals. Using inhibitors of the respiratory chain for chemical sequestration of respiratory segments we were able to identify the site where nitrite is reduced. The results confirm the ubiquinone/cyt bc1 couple as the reductant site where nitrite is recycled. The high affinity of NO to the heme-iron of cytochrome oxidase will result in an impairment of mitochondrial energy-production. "Nitrite tolerance" of angina pectoris patients using NO-donors may be explained in that way.
    Źródło:
    Acta Biochimica Polonica; 2000, 47, 4; 913-921
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    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:
    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:
    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
    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:
    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:
    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:
    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
    Tytuł:
    EPR-spin labelling measurements of thylakoid membrane fluidity during barely leaf senescence
    Autorzy:
    Jajic, I.
    Sarna, T.
    Wisniewska, A.
    Strzalka, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/79849.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    conference
    electron paramagnetic resonance
    spin labelling
    thylakoid membrane
    fluidity
    barley
    leaf senescence
    molecular oxygen
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Probing iso-1-cytochrome c structure by site-directed spin labeling and electron paramagnetic resonance techniques
    Autorzy:
    Pyka, Janusz
    Osyczka, Artur
    Turyna, Bohdan
    Blicharski, Wojciech
    Froncisz, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1044446.pdf
    Data publikacji:
    1999
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    iso-1-cytochrome c
    Saccharomyces cerevisiae
    site-directed mutagenesis
    spin label
    electron paramagnetic resonance
    Opis:
    A cysteine-specific methanethiosulfonate spin label was introduced into yeast iso-1-cytochrome c at three different positions. The modified forms of cytochrome c included: the wild-type protein labeled at naturally occurring C102, and two mutated proteins, S47C and L85C, labeled at positions 47 and 85, respectively (both S47C and L85C derived from the protein in which C102 had been replaced by threonine). All three spin-labeled protein derivatives were characterized using electron paramagnetic resonance (EPR) techniques. The continuous wave (CW) EPR spectrum of spin label attached to L85C differed from those recorded for spin label attached to C102 or S47C, indicating that spin label at position 85 was more immobilized and exhibited more complex tumbling than spin label at two other positions. The temperature dependence of the CW EPR spectra and CW EPR power saturation revealed further differences of spin-labeled L85C. The results were discussed in terms of application of the site-directed spin labeling technique in probing the local dynamic structure of iso-1-cytochrome c.
    Źródło:
    Acta Biochimica Polonica; 1999, 46, 4; 889-899
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spectroscopic study of a bis(imidazole) (octaethylporphyrinato)iron(III) complex
    Autorzy:
    Rutkowska, I.
    Dziliński, K.
    Kaczmarzyk, T.
    Stanek, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/146898.pdf
    Data publikacji:
    2013
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    electron paramagnetic resonance (EPR) spectroscopy
    Mössbauer spectroscopy
    low-spin iron porphyrin
    imidazole axial ligands
    Opis:
    Low-spin ferric octaethylporphyrinatoiron complex with two imidazole axial ligands [Fe(III)(OEP)(Im)2]+ has been investigated by electron paramagnetic resonance (EPR) and Mössbauer spectroscopies. It was found that the ground spin state corresponds to the electron configuration (dxy)2 (dxz, dyz)3 and planes of the imidazole axial ligands have a parallel mutual orientation. Ethyl groups bonded to pyrrole rings, as peripheral substituents, effect on the ground electron spin state of the complex studied and the relative orientation of the the imidazole axial ligands in a similar way like the phenyl substituents bonded to meso-carbon atoms of the porphyrin macrocycle. The temperature dependence of the Mössbauer spectra is discussed in terms of magnetic relaxation processes.
    Źródło:
    Nukleonika; 2013, 58, 3; 419-423
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of magnetic defects in NB2VSBO10 and NB6VSB3O25 compounds
    Badanie defektów magnetycznych związków NB2VSBO10 i NB6VSB3O25
    Autorzy:
    Typek, J.
    Bobrowska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/135810.pdf
    Data publikacji:
    2016
    Wydawca:
    Wyższa Szkoła Techniczno-Ekonomiczna w Szczecinie
    Tematy:
    vanadium catalysts
    magnetic properties
    electron paramagnetic resonance
    katalizatory wanadowe
    właściwości magnetyczne
    elektronowy rezonans paramagnetyczny
    Opis:
    Introduction and aim: Two new compounds from the Nb-V-Sb-O system will be scrutinized as possible catalysts, because many compounds from this system has showed promising catalytic properties. Since there is often a direct link between the number of defects and catalytic activity of a compound, these two materials will be investigated by magnetic methods to detect existing defects and to determine their structure and properties. Material and methods:NB2VSBO10and NB6VSB3O25 are relatively new compounds synthesized in Department of Inorganic and Analytical Chemistry, West Pomeranian University of Technology, Szczecin. Two magnetic methods have been used - dc magnetisation and electron paramagnetic resonance (EPR) spectroscopy. Results: Although the nominal valences of metal ions in both compounds suggested non-magnetic properties, very complex magnetic response was registered in both magnetisation and EPR measurements. Non-homogeneous distribution of magnetic ions makes possible formation of different types of spin clusters and strongly interacting magnetic subsystems. Conclusion: NB6VSB3O25 seems to be more promising catalyst than NB2VSBO10 as there are more magnetic defects in this compound.
    Wstęp i cel: Dwa nowe związki z układu Nb-V-Sb-O będą rozważane jako potencjalne katalizatory, gdyż wiele związków z tego układu wykazuje obiecujące właściwości katalityczne. Ponieważ często pomiędzy ilością defektów a aktywnością katalityczną istnieje zależność proporcjonalna, dwa te związki będą badane metodami magnetycznymi aby wykryć istniejące w nich defekty oraz określić ich strukturę i właściwości. Materiały i metody: NB2VSBO10 and Nb6VSb3O25zostały zsyntezowane stosunkowo niedawno w Katedrze Chemii Nieorganicznej i Analitycznej Zachodniopomorskiego Uniwersytetu Technologicznego w Szczecinie. Zastosowano dwie metody badania właściwości magnetycznych - stałoprądową magnetyzację i spektroskopii elektronowego rezonansu paramagnetycznego (EPR). Wyniki: Chociaż nominalna wartościowość jonów metali w obu związkach sugeruje brak magnetycznych właściwości, zarejestrowano bardzo złożoną odpowiedź magnetyczną w pomiarach magnetyzacji i EPR. Niejednorodny rozkład jonów magnetycznych powoduje tworzenie się różnego rodzaju klasterów spinowych i silnie oddziaływujących podukładów magnetycznych. Wnioski: NB6VSB3O25wydaje się być bardziej obiecującym katalizatorem niż NB2VSBO10, ponieważ w tym związku jest dużo więcej defektów magnetycznych.
    Źródło:
    Problemy Nauk Stosowanych; 2016, 5; 93-98
    2300-6110
    Pojawia się w:
    Problemy Nauk Stosowanych
    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:
    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:
    Concentration of free radicals in faba bean seeds after the pre-sowing treatment of the seeds with laser light
    Autorzy:
    Podlesny, J.
    Misiak, L.
    Koper, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/25440.pdf
    Data publikacji:
    2001
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    concentration
    laser light
    pre-sowing treatment
    electron paramagnetic resonance
    faba bean
    free radical
    plant cultivation
    seed
    Źródło:
    International Agrophysics; 2001, 15, 3
    0236-8722
    Pojawia się w:
    International Agrophysics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Singlet oxygen scavenging by tocopherol and plastochromanol under photooxidative stress in Arabidopsis thaliana
    Autorzy:
    Yadav, D.
    Rastogi, A.
    Szymanska, R.
    Kruk, J.
    Sedlarova, M.
    Pospisil, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/79876.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    conference
    singlet oxygen
    tocopherol
    plastochromanol
    chloroplast
    photooxidative stress
    Arabidopsis thaliana
    electron paramagnetic resonance
    confocal laser scanning microscopy
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    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
    Tytuł:
    Nowoczesne techniki spektroelektrochemiczne jako narzędzie dla badania procesów przeniesienia ładunku w polimerach skoniugowanych
    Spectroelectrochemical techniques as modern tools for investigating charge transfer processes in conjugated polymers
    Autorzy:
    Jarosz, T.
    Krukiewicz, K.
    Łapkowski, M.
    Domagała, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/142796.pdf
    Data publikacji:
    2015
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Przemysłu Chemicznego. Zakład Wydawniczy CHEMPRESS-SITPChem
    Tematy:
    spektroelektrochemia
    polimery przewodzące
    spektroskopia podczerwieni
    spektroskopia Ramana
    spektroskopia elektronowego rezonansu paramagnetycznego
    spectroelectrochemistry
    conjugated polymers
    infrared spectroscopy
    Raman spectroscopy
    electron paramagnetic resonance
    Opis:
    Techniki elektrochemiczne, pozwalające monitorować procesy przeniesienia ładunku, są szeroko wykorzystywane do badania związków organicznych z grupy polimerów skoniugowanych. Materiały te znajdują zastosowanie w optoelektronice i są podstawą opracowania takich urządzeń elektroniki organicznej jak nowoczesne panele fotowoltaiczne, diody elektroluminescencyjne, tranzystory polowe, okna elektrochromowe i sensory chemiczne. Właściwości tych materiałów oraz ich zmiany podczas przebiegu procesów przeniesienia ładunku są jednym z głównych tematów badań prowadzonych z wykorzystaniem technik spektroelektrochemicznych w Katedrze Fizykochemii i Technologii Polimerów Politechniki Śląskiej. Sztandarową techniką należącą do tej grupy jest spektroelektrochemia EPR-UV-Vis-NIR, pozwalająca jednocześnie śledzić zmiany właściwości optycznych układów skoniugowanych i powstawanie oraz zanik nośników ładunku. Powiązanie ze sobą tych informacji pozwala na przypisanie, obserwowanym w warstwie polimerowej, rodzajom nośników ładunku przejść elektronowych i kompleksowa dyskusja zachodzących procesów domieszkowania/ oddomieszkowania.
    Electrochemical analysis techniques, allowing charge transfer processes to be followed, are frequently utilised in the study of organic compounds belonging to the group of conjugated polymers. These materials are widely used in optoelectronics and are the basis for the development of organic electronics devices, such as modern photovoltaic panels, light-emitting diodes, field effect transistors, electrochromic windows and chemical sensors. The physicochemical properties of these materials and their changes in the course of charge transfer processes are one of the main topics of research, conducted with the use of spectroelectrochemical techniques, in the Department of Physical Chemistry and Technology of Polymers at the Silesian University of Technology. The leading technique belonging to this group is EPRUV- Vis-NIR spectroelectrochemistry, allowing the changes in optical properties of conjugated systems to be followed simultaneously with the generation and decay of charge carriers. Joint consideration of this information allows electronic transitions, observed in the polymer layer, to be assigned to types of charge carriers types and the processes of doping / dedoping to be comprehensively discussed.
    Źródło:
    Chemik; 2015, 69, 8; 485-490
    0009-2886
    Pojawia się w:
    Chemik
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modification of the hydrogen bonding network at the reversed micelles interface by near infrared radiation
    Autorzy:
    Walski, T.
    Gałecka, T.
    Grzeszczuk-Kuć, K.
    Komorowska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/148832.pdf
    Data publikacji:
    2013
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    electron paramagnetic resonance (EPR)
    hydrogen bonds
    near infrared radiation (NIR)
    cetyltrimethylammonium bromide (TCAB) reverse micelles
    TEMPO-palmitate spin probe
    water structure modification
    Opis:
    The purpose of this paper is to prove that near infrared radiation (NIR) modifies hydrogen bonds localized in the interface of reversed micelles. The degree of modification of the hydrogen bonds was monitored by TEMPO-palmitate spin probe introduced into the structure of reverse micelles formed by cetyltrimethylammonium bromide (CTAB) (TCAB/phosphate buffer/isooctane/hexanol and TCAB/NaCl/isooctane/hexanol (W = 15)). Electron paramagnetic resonance (EPR) spectra were performed on the argonated samples. The isotropic tumbling correlation time (τc) and the hyperfine coupling constant A+ = h0 – h+1 (h+1, and h0 correspond to the low-, and centre-field lines, respectively) were determined from the EPR spectra as a quantitative measure for monitoring the action of NIR radiation. A+ values depend on the composition of the water pool (1.640 mT for phosphate buffer and 1.630 mT for NaCl). NIR irradiation led to decrease in A+. This parameter reached the same value for both solutions (1.625 ± 0.003 and 1.626 ± 0.003 mT) after exposition to NIR. The tumbling correlation time after exposure to NIR decreased for TCAB/phosphate buffer/ isooctane/hexanol reversed micelles from 2.10 × 10–10 s to 1.44 × 10–10 s but did not change for TCAB/NaCl/isooctane/ hexanol). The results obtained confirm the possibility of modification of the hydrogen bonds by NIR radiation.
    Źródło:
    Nukleonika; 2013, 58, 3; 435-438
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Quantum magnetostriction effect resulting from the asymmetric structure of matter measured with EPR spectrometer
    Autorzy:
    Sikoń, Marek
    Bidzinska, Ewa
    Powiązania:
    https://bibliotekanauki.pl/articles/2204518.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    atomic arm of action
    non-paired electron/nucleon
    polar rotation
    Cosserat mechanics
    EPR
    electron paramagnetic resonance
    elektron niesparowany
    nukleon niesparowany
    atomowe ramię działania
    obrót biegunowy
    mechanika Cosserata
    elektronowy rezonans paramagnetyczny
    Opis:
    This paper explains the rotation and displacement as well as the couple and force stress in material with unpaired electrons/nucleons subjected to a magnetic field. This phenomenon is described in terms of quantum mechanics for nanoparticle and quantum statistical mechanics for loose nanomaterial. Quantitative calculations are carried out based on experimental data collected under the magnetic field of an EPR spectrometer from a set of nanocrystallites of hydrated copper sulfate.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 1; art. no. e144575
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electron paramagnetic resonance studies of manganese and cobalt ions in YAlO3 crystals
    Autorzy:
    Stefaniuk, I.
    Rogalska, I
    Suchocki, A
    Berkowski, M.
    Cieniek, B.
    Potera, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/174068.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    electron paramagnetic resonance (EPR)
    spin Hamiltonian
    Mn2+
    Mn4+
    Co2+
    Fe3+
    Cr3+
    Nd3+ and Er3+ ions
    YAlO3 (YAP) crystals
    Opis:
    The results of X-band electron paramagnetic resonance measurements of Mn2+ and Mn4+ ions in YAlO3 (YAP) crystals in the temperature range 100–300 K are presented. Additionally, we observe electron paramagnetic resonance spectra of unintentional impurities Fe3+ and Cr3+ in YAP crystals. The angular dependence for Mn ions in YAP crystals can be presented. We aim at obtaining a better insight into the spectroscopic properties of paramagnetic Mn centers and structural information about their nearest environment in YAP host and at determining the valence of manganese ion. In this paper we compare electron paramagnetic resonance spectra for Co and Mn ions in YAP crystals.
    Źródło:
    Optica Applicata; 2014, 44, 1; 113-121
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    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
      Wyświetlanie 1-35 z 35

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