Electron Paramagnetic Resonance and Optical Study of Radiation-Induced Defect Centers in Doped Silica Glasses

1985 ◽  
Vol 61 ◽  
Author(s):  
Robert N. Schwartz ◽  
Gregory L. Tangonan ◽  
G. Richard Blair ◽  
Walee Chamulitrat ◽  
Larry Kevan
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Radiation Dose ◽  
Optical Fibers ◽  
Optical Loss ◽  
Complex Spectrum ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Silica Glasses ◽  
Defect Centers ◽  
Electron Paramagnetic

ABSTRACTGamma- and UV-induced defect centers in germanium and fluorine doped silica have been studied by electron paramagnetic resonance (EPR) spectroscopy. The complex spectrum at g≃2 in γ-irradiated germanium doped glass corresponds to a superposition of resonances from several germanium E′-centers. In UV-irradiated samples, however, the EPR spectrum is dominated by only one type of germanium E′-centers. Significant spectral simplification of γ-irradiated germanium doped silica can be achieved by heating or broadband photoirradiation. Similar results are observed in multimode germanium doped core optical fibers. UV-induced optical loss spectra in the 0.5–1.5 μm wavelength range were also measured in these core fibers as well as the growth kinetics of the UL-induced absorption. Gamma-irradiation of fluorine doped silica generated two different types of silicon E′-centers, Ea1. At lower radiation dose one sees a mixture of Ea1 and Ea2, but at higher radiation dose Ea2 dominates. A spectrum dominated by the Ea2 variant is also observed in LW-irradiated samples and in photobleached low gamma dose samples.

scholarly journals Determining the Dose of Radiation and Radurisation Effects on the Antioxidant Activity of Fish and the Thermophysical Characteristics of Fish Muscle Tissue

Foods ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 130
Author(s):  
Roza T. Timakova ◽  
Sergey L. Tikhonov ◽  
Nataliya V. Tikhonova ◽  
Sergey V. Shikhalev
Keyword(s):  
Antioxidant Activity ◽  
Electron Paramagnetic Resonance ◽  
Radiation Dose ◽  
Muscle Tissue ◽  
Radiation Treatment ◽  
Fish Muscle ◽  
Radiation Processing ◽  
Thermophysical Characteristics ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

The aim of this article is to develop a method for determining the dose of radiation in the processing of chilled fish and its effect on the antioxidant activity and thermophysical characteristics of muscle tissue. Radiation processing of chilled fish was performed using a linear electron accelerator model LEA-10-10S2. The dose of radiation was determined by the method of electron-paramagnetic resonance. After being treated with ionizing radiation, the cooled fish meets the requirements of the technical regulations of TR TU 021/2011 “On food safety” and TR EAEU 040/2016 “On the safety of fish and fish products”. As a result of our research, a correlation was established between the area of the Electron Paramagnetic Resonance (EPR) signal and the absorbed dose of the radiation dose. We proved a decrease in the antioxidant activity of muscle tissue of fish with an increase in radiation dose. It is established that radiation treatment of chilled fish affects the thermophysical properties of muscle tissue.

Spin reorientation transition and spin dynamics study of perovskite orthoferrite TmFeO3 detected by electron paramagnetic resonance

2020 ◽  
Vol 22 (37) ◽  
pp. 21403-21411
Author(s):  
Poorva Sharma ◽  
Jiyu Fan ◽  
Ashwini Kumar ◽  
Arvind Yogi ◽  
Yisheng Chai ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Spin Dynamics ◽  
Spin Reorientation ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Spin Reorientation Transition ◽  
Different Temperatures ◽  
Electron Paramagnetic

(Right) EPR spectrum of TmFeO3 from 20–300 K. (Left) (a) Asymmetry behavior w.r.t. temperature (K), (b) ΔHppvs. T, (c) Plot as ln(ΔHpp × T) vs. 1000/T, (d) DIN (inset represents χdcvs. T at different temperatures).

scholarly journals Concentration of Fe(3+)-Triapine in BEAS-2B Cells

2019 ◽  
Vol 20 (12) ◽  
pp. 3062 ◽  
Author(s):  
William E. Antholine ◽  
Charles R. Myers
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Tumor Cells ◽  
Iron Uptake ◽  
Antitumor Agent ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Epr Method ◽  
First Time ◽  
Electron Paramagnetic ◽  
In Cells

An electron paramagnetic resonance (EPR) method was used to determine the concentration of the antitumor agent Triapine in BEAS-2B cells when Triapine was bound to iron (Fe). Knowledge of the concentration of Fe-Triapine in tumor cells may be useful to adjust the administration of the drug or to adjust iron uptake in tumor cells. An EPR spectrum is obtained for Fe(3+)-Triapine, Fe(3+)(Tp)2+, in BEAS-2B cells after addition of Fe(3+)(Tp)2+. Detection of the low spin signal for Fe(3+)(Tp)2+ shows that the Fe(3+)(Tp)2+ complex is intact in these cells. It is proposed that Triapine acquires iron from transferrin in cells including tumor cells. Here, it is shown that iron from purified Fe-transferrin is transferred to Triapine after the addition of ascorbate. To our knowledge, this is the first time that the EPR method has been used to determine the concentration of an iron antitumor agent in cells.

An Experimental Technique for Studying Chemisorption Reactions by Means of Electron Paramagnetic Resonance Spectroscopy

1972 ◽  
Vol 26 (2) ◽  
pp. 239-241 ◽  
Author(s):  
Eugene P. Scheide ◽  
George G. Guilbault
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Experimental Method ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Cupric Chloride ◽  
Resonance Spectroscopy ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Before And After ◽  
Chemisorption Bond ◽  
Electron Paramagnetic

A new experimental method and a specially designed EPR cell are described for use in the study of chemisorption reactions. By studying the EPR spectrum of a surface both before and after chemisorption, it can be shown whether unpaired d electrons are used in the chemisorption bond and the nature of this bond. The EPR spectra of a cupric chloride surface, both before and after a gaseous ligand (diisopropyl methyl phosphonate) is chemisorbed, are shown and the results are interpreted in terms of the type of bond formed.

A cyanide-bridged heterometallic coordination polymer constructed from square-planar [Ni(CN)4]2−: synthesis, crystal structure, thermal decomposition, electron paramagnetic resonance (EPR) spectrum and magnetic properties

2016 ◽  
Vol 72 (7) ◽  
pp. 555-560 ◽  
Author(s):  
Ying-Lian Qin ◽  
Bin-Wu Yang ◽  
Gao-Feng Wang ◽  
Hong Sun
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Building Blocks ◽  
Transition Metal Ions ◽  
Supramolecular Network ◽  
Electron Configuration ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Design Elements ◽  
Square Planar ◽  
Electron Paramagnetic

Square-planar complexes are commonly formed by transition metal ions having ad8electron configuration. Planar cyanometallate anions have been used extensively as design elements in supramolecular coordination systems. In particular, square-planar tetracyanometallate(II) ions,i.e.[M(CN)4]2−(MII= Ni, Pd or Pt), are used as good building blocks for bimetallic Hofmann-type assemblies and their analogues. Square-planar tetracyanonickellate(II) complexes have been extensively developed withN-donor groups as additional co-ligands, but studies of these systems usingO-donor ligands are scarce. A new cyanide-bridged CuII–NiIIheterometallic compound, poly[[diaquatetra-μ2-cyanido-κ8C:N-nickel(II)copper(II)] monohydrate], {[CuIINiII(CN)4(H2O)2]·H2O}n, has been synthesized and characterized by X-ray single-crystal diffraction analyses, vibrational spectroscopy (FT–IR), thermal analysis, electron paramagnetic resonance (EPR) and magnetic moment measurements. The structural analysis revealed that it has a two-dimensional grid-like structure built up of cationic [Cu(H2O)2]2+and anionic [Ni(CN)4]2−units connected through bridging cyanide ligands. The overall three-dimensional supramolecular network is expanded by a combination of interlayer O—H...N and intralayer O—H...O hydrogen-bond interactions. The first decomposition reactions take place at 335 K under a static air atmosphere, which illustrates the existence of guest water molecules in the interlayer spaces. The electron paramagnetic resonance (EPR) spectrum confirms that the CuIIcation has an axial coordination symmetry and that the unpaired electrons occupy thed_{{{{x}^2}-y^2} orbital. In addition, magnetic investigations showed that antiferromagnetic interactions exist in the CuIIatoms through the diamagnetic [Ni(CN)4]2−ion.

scholarly journals DEPENDENCE OF ELECTRON PARAMAGNETIC RESONANCE (EPR) SPECTRUM PARAMETERS ON THE KIND OF MEAT AND FISH TREATED BY IONIZING RADIATION

2018 ◽  
Vol 97 (9) ◽  
pp. 873-876
Author(s):  
R. T. Timakova ◽  
Sergei L. Tikhonov ◽  
O. V. Evdokimova ◽  
I. V. Butenko
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ionizing Radiation ◽  
Bone Tissue ◽  
Radiation Treatment ◽  
Raw Materials ◽  
Food Products ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Epr Signal ◽  
Electron Paramagnetic

Regulation of the use of ionizing radiation for treating food products and agricultural raw materials in Russia in 2017 suggests a wide dissemination of radiation technologies in the food industry, but manufacturers of food products processed by ionizing radiation do not indicate on the label the relevant information. Because of this, the identification of the domestic consumer market of food products processed by ionizing radiation will reduce the number of violations of requirements of state standard State standards (GOST) 33800-2016 “Production of food irradiated. General labeling requirements”. To determine whether irradiation of food raw materials and foodstuff, used the method of electron paramagnetic resonance (EPR), with each of the food products treated by ionizing radiation has its own characteristic EPR spectrum. In this regard, the aim of the research is to identify the dependence of the parameters of the EPR spectrum from meat, fish and poultry treated with ionizing radiation. Samples of bone tissue (SBT) meat, fish and poultry were subjected to radiation treatment with a linear electron accelerator model UELR-10-10С2 with energies up to 10 MeV. Studies of samples were carried out on the portable automated EPR spectrometer brand Labrador Expert X-band. Found that despite treatment samples of bone tissue with the same dose of ionizing radiation (12 kGy), the EPR signal depends on the type of vertebrates, the structure of the tissue sample, and other factors. Bone samples of beef and pork have a higher sensitivity to irradiation. Recorded a steady correlation between increasing the area of the EPR signal parameters: amplitude is of 0.99, the width of the peak signal, respectively 0,979 (the degree of strength of statistical relationships Chedoke very high). Processing of the obtained results of the EPR spectrum provides a high degree of confidence (p≤0.05) to identify how previously non-irradiated and radiation-processed various meats, fish and poultry.

scholarly journals Application of Numerical Analysis of the Shape of Electron Paramagnetic Resonance Spectra for Determination of the Number of Different Groups of Radicals in the Burn Wounds

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Paweł Olczyk ◽  
Katarzyna Komosinska-Vassev ◽  
Paweł Ramos ◽  
Łukasz Mencner ◽  
Krystyna Olczyk ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Repair Process ◽  
Spectral Shape ◽  
Dipolar Interactions ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Burn Wounds ◽  
Best Fitting ◽  
Electron Paramagnetic

Background. The evidence exists that radicals are crucial agents necessary for the wound regeneration helping to enhance the repair process. Materials and methods. The lineshape of the electron paramagnetic resonance (EPR) spectra of the burn wounds measured with the low microwave power (2.2 mW) was numerically analyzed. The experimental spectra were fitted by the sum of two and three lines. Results. The number of the lines in the EPR spectrum corresponded to the number of different groups of radicals in the natural samples after thermal treatment. The component lines were described by Gaussian and Lorentzian functions. The spectra of the burn wounds were superposition of three lines different in shape and in linewidths. The best fitting was obtained for the sum of broad Gaussian, broad Lorentzian, and narrow Lorentzian lines. Dipolar interactions between the unpaired electrons widened the broad Gaussian and broad Lorentzian lines. Radicals with the narrow Lorentzian lines existed mainly in the tested samples. Conclusions. The spectral shape analysis may be proposed as a useful method for determining the number of different groups of radicals in the burn wounds.

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