Catalytic and Electron Paramagnetic Resonance Spectroscopic Characterization of γ-Al2O3 in a Non-Thermal Plasma

2005 ◽  
Vol 8 (1) ◽  
Author(s):  
Ulf Roland ◽  
Frank Holzer ◽  
Andreas Pöppl ◽  
Frank-Dieter Kopinke
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Thermal Plasma ◽  
Pore Volume ◽  
Structural Changes ◽  
Peroxide Radical ◽  
Paramagnetic Resonance ◽  
Non Thermal Plasma ◽  
The Impact ◽  
Electron Paramagnetic ◽  
Inner Pore

AbstractIn order to evaluate the potential of the combination of non-thermal plasma (NTP) and in situ heterogeous catalysis (plasma catalysis) for the improvement of efficiency and selectivity towards total oxidation of organic pollutants, the impact of plasma processes inside the inner pore volume of porous materials was investigated by means of catalytic reactions and spectroscopy. Besides studying the conversion of organic model substances, electron paramagnetic resonance (EPR) spectroscopy was applied to detect both the formation of radical species by the NTP and the initiation of structural changes to the catalyst. The presence of short-lived oxidizing species and plasma effects in the inner pore volume of porous catalysts (alumina in this case) could be clearly shown by detecting a significant influence on the oxidation process and the formation of a paramagnetic site which can be correlated to an aluminum peroxide radical: Al-O-O. The relatively stable paramagnetic center (lifetime > 14 days) was formed by the NTP independently of the gas atmosphere, namely its oxygen content. The signal was not significantly affected by the application of reducing agents to the sample.

scholarly journals The Impact of Hydrogenation on Structural and Superconducting Properties of FeTe0.65Se0.35 Single Crystals

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7900
Author(s):  
Stanislav I. Bondarenko ◽  
Anatolij I. Prokhvatilov ◽  
Roman Puźniak ◽  
Jarosław Piętosa ◽  
Andrey A. Prokhorov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Paramagnetic Resonance ◽  
Single Crystals ◽  
Structural Changes ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Paramagnetic Resonance ◽  
The Impact ◽  
Electron Paramagnetic ◽  
Diffusion Of Hydrogen

Properties of FeTe0.65Se0.35 single crystals, with the onset of critical temperature (Tconset) at 15.5 K, were modified via hydrogenation performed for 10–90 h, at temperatures ranging from 20 to 250 °C. It was found that the tetragonal matrix became unstable and crystal symmetry lowered for the samples hydrogenated already at 200 °C. However, matrix symmetry was not changed and the crystal was not destroyed after hydrogenation at 250 °C. Bulk Tcbulk, determined at the middle of the superconducting transition, which is equal to 12–13 K for the as grown FeTe0.65Se0.35, rose by more than 1 K after hydrogenation. The critical current density studied in magnetic field up to 70 kOe increased 4–30 times as a consequence of hydrogenation at 200 °C for 10 h. Electron paramagnetic resonance measurements also showed higher values of Tcbulk for hydrogenated crystals. Thermal diffusion of hydrogen into the crystals causes significant structural changes, leads to degeneration of crystal quality, and significantly alters superconducting properties. After hydrogenation, a strong correlation was noticed between the structural changes and changes in the parameters characterizing the superconducting state.

Electron paramagnetic resonance reveals age-related myosin structural changes in rat skeletal muscle fibers

2001 ◽  
Vol 280 (3) ◽  
pp. C540-C547 ◽  
Author(s):  
Dawn A. Lowe ◽  
Jack T. Surek ◽  
David D. Thomas ◽  
LaDora V. Thompson
Keyword(s):  
Skeletal Muscle ◽  
Electron Paramagnetic Resonance ◽  
Young Adult ◽  
Structural State ◽  
Structural Changes ◽  
Aged Rats ◽  
Paramagnetic Resonance ◽  
Specific Tension ◽  
Age Related ◽  
Electron Paramagnetic

We tested the hypothesis that low specific tension (force/cross-sectional area) in skeletal muscle from aged animals results from structural changes in myosin that occur with aging. Permeabilized semimembranosus fibers from young adult and aged rats were spin labeled site specifically at myosin SH1 (Cys-707). Electron paramagnetic resonance (EPR) was then used to resolve and quantify the structural states of the myosin head to determine the fraction of myosin heads in the strong-binding (force generating) structural state during maximal isometric contraction. Fibers from aged rats generated 27 ± 0.8% less specific tension than fibers from younger rats ( P < 0.001). EPR spectral analyses showed that, during contraction, 31.6 ± 2.1% of myosin heads were in the strong-binding structural state in fibers from young adult animals but only 22.1 ± 1.3% of myosin heads in fibers from aged animals were in that state ( P = 0.004). Biochemical assays indicated that the age-related change in myosin structure could be due to protein oxidation, as indicated by a decrease in the number of free cysteine residues. We conclude that myosin structural changes can provide a molecular explanation for age-related decline in skeletal muscle force generation.

MAS NMR and EPR study of structural changes in talc and montmorillonite induced by grinding

Clay Minerals ◽  
2016 ◽  
Vol 51 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Roger Borges ◽  
Lívia Macedo Dutra ◽  
Andersson Barison ◽  
Fernando Wypych
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Electron Paramagnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
Cation Exchange ◽  
Structural Changes ◽  
Environmental Changes ◽  
Milling Process ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

AbstractThe milling process in the solid-state 2:1 clay minerals, montmorillonite and talc, which have different cation exchange capacities, is reported here. Several instrumental techniques were used to monitor systematically the products formed. The dehydroxylation/amorphization of the montmorillonite and talc structures occurs within 3 and 6 h of milling, respectively. Electron paramagnetic resonance spectra indicated that structural Mn2+ was oxidized more quickly in the montmorillonite structure than in talc, while the paramagnetic defects increased during milling. Nuclear magnetic resonance was also used to monitor the environmental changes for Si and Al during milling.

scholarly journals Tetrachloroaurate (III)–induced Oxidation Increases Non-thermal Plasma-induced Oxidative Stress

2021 ◽  
Author(s):  
Yasumasa Okazaki ◽  
Kanako Sasaki ◽  
Nanami Ito ◽  
Hiromasa Tanaka ◽  
Ken-Ichiro Matsumoto ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Thermal Plasma ◽  
Thiobarbituric Acid ◽  
Spin Adduct ◽  
Paramagnetic Resonance ◽  
Cancer Cell Death ◽  
Positive Ions ◽  
Non Thermal Plasma ◽  
Electron Paramagnetic ◽  
Elevated Lipid

Abstract Non-thermal plasma (NTP) devices have been explored for medical applications. NTP devices discharge electrons, positive ions, ultraviolet, and reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as the hydroxyl radical (●OH), singlet oxygen (1O2), superoxide (O2●−), hydrogen peroxide (H2O2), ozone, and nitric oxide, at near-physiological temperature. At preclinical stages or in human clinical trials, NTP promotes blood coagulation, eradication of bacterial, viral, and biofilm-related infections, wound healing, and cancer cell death. Here, we observed that ferric, vanadium, and gold(III) ions, measured by 2-thiobarbituric acid-reactive substances (TBARS) in combination with NTP exposure, significantly elevated lipid peroxidation. Using 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (M4PO) as a spin probe in electron paramagnetic resonance (EPR), we observed that tetrachloroaurate (III) yielded an M4PO-X spin adduct. Tetrachloroaurate-induced oxidation was attenuated efficiently by reduced (GSH) and oxidized glutathione (GSSG), while glycine (Gly) and L-glutamate (Glu), components of GSH, were ineffective. Furthermore, GSH and GSSG efficiently suppressed tetrachloroaurate-induced lipid peroxidation, while Gly and Glu were ineffective in suppressing TBARS elevation. These results indicate that tetrachloroaurate-induced oxidation is attenuated by GSH as well as GSSG. Further studies are warranted to elucidate the redox reactions between metal ions and biomolecules to advance the clinical application of NTP.

scholarly journals Changes in the fraction of strongly attached cross bridges in mouse atrophic and hypertrophic muscles as revealed by continuous wave electron paramagnetic resonance

2019 ◽  
Vol 316 (5) ◽  
pp. C722-C730
Author(s):  
Laura Galazzo ◽  
Leonardo Nogara ◽  
Francesca LoVerso ◽  
Antonino Polimeno ◽  
Bert Blaauw ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Spin Label ◽  
Structural Changes ◽  
Continuous Wave ◽  
Myosin Head ◽  
Force Generation ◽  
Paramagnetic Resonance ◽  
The Difference ◽  
Cross Bridges ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR), coupled with site-directed spin labeling, has been proven to be a particularly suitable technique to extract information on the fraction of myosin heads strongly bound to actin upon muscle contraction. The approach can be used to investigate possible structural changes occurring in myosin of fiber s altered by diseases and aging. In this work, we labeled myosin at position Cys707, located in the SH1-SH2 helix in the myosin head cleft, with iodoacetamide spin label, a spin label that is sensitive to the reorientational motion of this protein during the ATPase cycle and characterized the biochemical states of the labeled myosin head by means of continuous wave EPR. After checking the sensitivity and the power of the technique on different muscles and species, we investigated whether changes in the fraction of strongly bound myosin heads might explain the contractile alterations observed in atrophic and hypertrophic murine muscles. In both conditions, the difference in contractile force could not be justified simply by the difference in muscle mass. Our results showed that in atrophic muscles the decrease in force generation was attributable to a lower fraction of strongly bound cross bridges during maximal activation. In contrast in hypertrophic muscles, the increase in force generation was likely due to several factors, as pointed out by the comparison of the EPR experiments with the tension measurements on single skinned fibers.

STRUCTURAL INVESTIGATION OF GADOLINIUM DOPED YTTRIUM-ALUMINOSILICATE GLASSES AND VITROCERAMICS

2008 ◽  
Vol 22 (12) ◽  
pp. 1933-1939
Author(s):  
S. SIMON
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Structural Changes ◽  
Structural Investigation ◽  
Differential Analysis ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Aluminosilicate Glasses ◽  
Heat Treated ◽  
Electron Paramagnetic

Structural changes induced by heat treatment of yttrium-aluminosilicate glasses doped with gadolinium were studied by thermal differential analysis, X-ray diffraction and Gd 3+ electron paramagnetic resonance (EPR). A small amount of yttrium was replaced by gadolinium in the host glass because yttrium and gadolinium cations are quite similar, and gadolinium can be used as a structural sensor by electron paramagnetic resonance measurements. EPR results evidence small changes in the surroundings of Gd 3+ ions in the heat treated samples, as compared with the as prepared ones.

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