scholarly journals Acoustically induced coherent spin trapping

2021 ◽  
Vol 7 (44) ◽  
Author(s):  
Alberto Hernández-Mínguez ◽  
Alexander V. Poshakinskiy ◽  
Michael Hollenbach ◽  
Paulo V. Santos ◽  
Georgy V. Astakhov
Keyword(s):  
Spin Trapping ◽  
Coherent Spin

Enhancement of hydroxyl radical generation by phenols and their reaction intermediates during ozonation

1998 ◽  
Vol 38 (6) ◽  
pp. 147-154 ◽  
Author(s):  
Hideo Utsumi ◽  
Sang-Kuk Han ◽  
Kazuhiro Ichikawa
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Spin Trapping ◽  
Active Species ◽  
Generation Rate ◽  
Peak Height Ratio ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Phenol Derivatives ◽  
Semiquinone Radicals

Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 X 10-6M of DMPO-OH, indicating that 1.4% of •OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance •OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.

Photoredox Reactions of Iodo Iron(III) Complexes Containing Tetradentate Ligands

2001 ◽  
Vol 66 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jozef Šima ◽  
Dáša Lauková ◽  
Vlasta Brezová
Keyword(s):  
Schiff Bases ◽  
Spin Trapping ◽  
Molar Ratio ◽  
Oh Radicals ◽  
Solvated Electrons ◽  
Open Chain ◽  
Tetradentate Ligands ◽  
Visible Irradiation ◽  
Epr Spin Trapping ◽  
Spin Trapping Technique

Photoredox reactions occurring in irradiated methanolic solutions of trans-[FeIII(R,R'-salen)(CH3OH)I], where R,R'-salen2- are N,N'-ethylenebis(R,R'-salicylideneiminato), tetradentate open-chain N2O2-Schiff bases with R,R' = H, 5-Cl, 5-Br, 3,5-di-Br, 3,5-di-(CH3), 3-OCH3, 5-OCH3, have been investigated and their mechanism proposed. The complexes are redox-stable in the dark. Ultraviolet and/or visible irradiation of methanolic solution of the complexes induces photoreduction of Fe(III) to Fe(II). Depending on the composition of the irradiated solutions, •CH2OH radicals or solvated electrons were identified by the EPR spin trapping technique. The final product of the photooxidation coupled with the photoreduction of Fe(III) is formaldehyde and the molar ratio of Fe(II) and CH2O is close to 2 : 1. The efficiency of the photoredox process is strongly wavelength-dependent and influenced by the peripheral groups R,R' of the tetradentate ligands.

In Vivo Spin Trapping of Glyceryl Trinitrate–Derived Nitric Oxide in Rabbit Blood Vessels and Organs

Circulation ◽  
1995 ◽  
Vol 92 (7) ◽  
pp. 1876-1882 ◽  
Author(s):  
Alexander Mülsch ◽  
Peter Mordvintcev ◽  
Eberhard Bassenge ◽  
Frank Jung ◽  
Bernd Clement ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Glyceryl Trinitrate ◽  
Blood Vessels ◽  
Spin Trapping ◽  
Rabbit Blood

scholarly journals Electrospun Nanosystems Based on PHBV and ZnO for Ecological Food Packaging

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2123
Author(s):  
Maria Râpă ◽  
Maria Stefan ◽  
Paula Popa ◽  
Dana Toloman ◽  
Cristian Leostean ◽  
...  
Keyword(s):  
Food Packaging ◽  
Spin Trapping ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
Hno3 Solution ◽  
X Ray ◽  
Trapping Method ◽  
Ft Ir ◽  
Doped Zno ◽  
Electron Paramagnetic

The electrospun nanosystems containing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and 1 wt% Fe doped ZnO nanoparticles (NPs) (with the content of dopant in the range of 0–1 wt% Fe) deposited onto polylactic acid (PLA) film were prepared for food packaging application. They were investigated by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), antimicrobial analysis, and X-ray photoelectron spectrometry (XPS) techniques. Migration studies conducted in acetic acid 3% (wt/wt) and ethanol 10% (v/v) food simulants as well as by the use of treated ashes with 3% HNO3 solution reveal that the migration of Zn and Fe falls into the specific limits imposed by the legislation in force. Results indicated that the PLA/PHBV/ZnO:Fex electrospun nanosystems exhibit excellent antibacterial activity against the Pseudomonas aeruginosa (ATCC-27853) due to the generation of a larger amount of perhydroxyl (˙OOH) radicals as assessed using electron paramagnetic resonance (EPR) spectroscopy coupled with a spin trapping method.

Microwave Induced Free Radicals Production in Red Wine and Model Wine by EPR Spin Trapping

2021 ◽  
Author(s):  
Jiangfeng Yuan ◽  
Zhuoyao Chen ◽  
Dahong Wang ◽  
Minggui Gong ◽  
Zhijun Qiu
Keyword(s):  
Free Radicals ◽  
Red Wine ◽  
Spin Trapping ◽  
Epr Spin Trapping

Observation of the dispersion relations for quantized coherent spin waves excited by a microwave antenna

2020 ◽  
Vol 102 (21) ◽  
Author(s):  
Yoichi Shiota ◽  
Ryusuke Hisatomi ◽  
Takahiro Moriyama ◽  
Teruo Ono
Keyword(s):  
Spin Waves ◽  
Dispersion Relations ◽  
Microwave Antenna ◽  
Coherent Spin
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