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Wyszukujesz frazę "electron spin resonance" wg kryterium: Temat


Tytuł:
Antioxidant properties of wines produced in the Podkarpacie region
Autorzy:
Szterk, A.
Stefaniuk, I.
Cieniek, B.
Kuźma, M.
Powiązania:
https://bibliotekanauki.pl/articles/147112.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron spin resonance (ESR)
POBN spin trap
superoxide radial anion
Polish wines
Opis:
The wine is famous and popular drink having properties of reactive oxygen species scavenging. In this paper we study the antioxidant activity of the selected wines produced in the south-east region of Poland, in Subcarpathian Voivodeship, in the Podkarpacie region. We have concentrated our studies on the superoxide radical anion O2 •–. We have used electron spin resonance spectroscopy (ESR) as it is the best method for radical detection. The nitrone spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) has been used in the experiment. The radical scavenging ability of wines were determined from the changing intensity of the spectrum in time.
Źródło:
Nukleonika; 2013, 58, 3; 447-450
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of Conductive Cocoon Silk Composites
Synteza kompozytów z przewodzącymi kokonami jedwabnymi
Autorzy:
Kaitsuka, Y.
Goto, H.
Powiązania:
https://bibliotekanauki.pl/articles/233610.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
electron spin resonance
polyaniline
secondary doping
silk
elektronowy rezonans spinowy
polianilina
jedwab
Opis:
Herein we report on the preparation of polyaniline (PANI) composite using a cocoon by in situ chemical oxidative polymerisation. The composites thus prepared were characterised by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), infrared (IR), and electron spin resonance (ESR) spectroscopy. We confirmed the PANI/cocoon composite and subsequent carbonisation allowed the formation of micro-sized wafer-shaped carbon. The polymerisation reaction occurs in a chiral reaction field of the silk surface, which can be referred to as bio-interface polymerisation.
W artykule opisano przygotowanie polianilinowych (PANI) kompozytów przy zastosowaniu kokonów i przeprowadzeniu in situ chemicznej utleniającej polimeryzacji. Wytworzone kompozyty zostały scharakteryzowane za pomocą skaningowego mikroskopu elektronowego (SEM), analizy termograwimetrycznej (TGA), spektrofotometrii w podczerwieni (IR) oraz elektronowego rezonansu spinowego (ESR). Potwierdzono, że otrzymane kompozyty, a następnie ich karbonizacja umożliwiły powstawanie mikroskopijnej wielkości płytek węglowych.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 1 (121); 17-23
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of selected amino acids on the dynamic properties of the liposome membranes : ESR study
Autorzy:
Man, D.
Broda, M.
Buczek, A.
Kawecka, A.
Siodłak, D.
Powiązania:
https://bibliotekanauki.pl/articles/146690.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
EYL liposomes
electron spin resonance (ESR) method
N-methylation
amino acids
peptides
Opis:
In this work the changes in the fluidity of liposome membranes caused by alanine and butyrine derivatives (Ac-Ala-NMe2 and Ac-Abu-NMe2) were investigated. Liposomes were obtained in the process of egg yolk lecithin (EYL) sonication. The concentration of the admixture in the proportion to EYL varied from 0 to 25% mole. The electron spin resonance (ESR) spectroscopy was used with two different spins probes. Each spin probe penetrates different regions of liposome membrane. The TEMPO probe occurs both in the hydrophobic part of the membrane and in the water environment what allows to determine the spectroscopic parameter F of division of this probe into the membrane and its water surrounding. DOXYL is localized in the central part of the lipid bilayer and is used to obtain the spectroscopic parameter τ – rotation correlation time – whose value gives information about fluidity changes in the middle of the lipid bilayer. The study indicated that the tested as admixtures N-methylated model peptides significantly changed the fluidity of liposome membranes. The dynamic of this process depends both on amino acids derivative and on the membrane region. Both studied compounds increased the fluidity of the surface layer of liposome membrane. At the same time, butyrine derivative caused the stiffening of the middle part of liposome bilayer, but alanine derivative slightly increased the fluidity of this region.
Źródło:
Nukleonika; 2013, 58, 3; 443-446
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron spin resonance (ESR) spectra of butylated hydroxytoluene (BHT) as evidence of free radical formation in electrostatic discharge (ESD) damaged lubricating oils
Spektra elektronowego rezonansu spinowego (ESR) butylowanego hydroksytoluenu (BHT) jako dowód powstawania wolnych rodników w trakcie wyładowań elektrostatycznych (ESD) w turbinowych olejach smarnych
Autorzy:
Duchowski, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/188570.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
turbine lubricating oil
antioxidant additives
free radical oxidation
electron spin resonance
turbinowe oleje smarne
antyutleniacze
wolnorodnikowe utleniania
elektronowy resonans spinowy
Opis:
Electrostatic discharges were generated in typical ISO VG 46 cSt turbine lubricating oil by passing the oil through a glass fibre filter element at a hydraulic load of 0.06 L*min-1*cm-2. The oil exhibited electrical conductivity of 8 pS*m-1 at 25°C. The experiment was performed at room temperature. The maximum amplitude of ESD arcing events recorded was approximately –500 V. The magnitude of these arcing events was sufficient to generate a free radical formation of the BHT antioxidant additive generally employed as an antioxidant in typical turbine lubricating oil formulations. The free radical formation was evidenced by a clearly observable ESR signal corresponding to the BHT radical as recorded on an X-Band MiniScope MS100 spectrometer with a resonant frequency of 9.43 GHz and a maximum field sweep of 400 mT. These results indicate that ESD can well be responsible for initiating the free radical polymerization process postulated to result in varnish formation in turbine lubricating oils.
Wyładowania elektrostatyczne zostały wygenerowane w typowym oleju ISO VG 46 cSt stosowanym jako olej smarny w turbinach gazowych w trakcie przepływu oleju przez element filtracyjny na bazie włókien szklanych przy obciążeniu hydraulicznym wynoszącym 0,06 L*min-1*cm-2. Przewodowość oleju wynosiła 8 pS*m-1 przy temperaturze 25°C. Eksperyment został przeprowadzony w temperaturze pokojowej. Maksymalna amplituda wyładowań elektrostatycznych osiągnęła –500 V. Amplituda wyładowań była wystarczająca, by doprowadzić do powstawania wolnych rodników BHT stosowanym jako antyutleniacz w typowych formulacjach turbinowych olejów smarnych. Obecność wolnego rodnika BHT została zarejestrowana za pomocą X-Band MiniScope MS100 spektrometru z częstotliwością rezonasową 9,43 GHz o maksymalnym zasięgu pola magnetycznego 400 mT. Zarejestrowane wyniki wskazują, że ESD może być źródłem powstawania wolnych rodników i prowadzić do wolnorodnikowych procesów polimeryzacyjnych odpowiedzialnych za tworzenie się zanieczyszczeń osadowych w turbinowych olejach smarnych.
Źródło:
Tribologia; 2014, 4; 43-52
0208-7774
Pojawia się w:
Tribologia
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:
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:
EMR study and superposition model analysis of Cr3+ and Fe3+ impurity ions in mullite powders used in aerospace industry
Autorzy:
Stefaniuk, I.
Rogalska, I..
Powiązania:
https://bibliotekanauki.pl/articles/146307.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron magnetic resonance (EMR)
mullites
spin Hamiltonian (SH)
superposition model (SPM)
Opis:
In this work, the electron magnetic resonance (EMR) spectra of the mullites powders were measured for different grain sizes (0.07 and 0.12 mm). We have used EMR spectroscopy at X-band, combined with superposition model (SPM) calculations to reveal electronic structure and establish correlations between structure, and surroundings of these complexes.
Źródło:
Nukleonika; 2015, 60, No. 3, part 1; 399-403
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:
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:
Modelling of EMR data for Fe2+(S=2) ions in a [2Fe-2S] cluster in the reduced ferredoxin
Autorzy:
Rudowicz, Cz.
Piwowarska, D.
Gnutek, P.
Powiązania:
https://bibliotekanauki.pl/articles/146266.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
[2Fe-2S] cluster
electron magnetic resonance (EMR)
Fe2+ ions
microscopic spin Hamiltonian (MSH)
zero field splitting (ZFS) parameters
Opis:
The modelling techniques employed in this study utilize structural data to enable correlation of EMR data – described by the spin Hamiltonian (SH) and optical spectroscopy data – described by the crystal field (CF) Hamiltonian. These techniques enable also to predict magnetic and spectroscopic properties of 3dN ions, especially 3d4 and 3d6 ions, in various systems. Specific applications are considered for [Fe2+ and Fe3+] binuclear centres in [2Fe-2S] cluster in the reduced ferredoxin and related biological molecules. The background for model calculations of the zero-field splitting (ZFS) parameters and/or crystal field parameters and the capabilities of the two major techniques used will be presented in the full paper. Here, we present preliminary results of the microscopic spin Hamiltonian (MSH) modelling for Fe2+ (3d6) ions in the reduced ferredoxin.
Źródło:
Nukleonika; 2013, 58, 3; 347-350
0029-5922
1508-5791
Pojawia się w:
Nukleonika
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:
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

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