An investigation of anthraquinone-catalysed alkaline pulping via component modeling and electron spin resonance experiments

1980 ◽  
Vol 58 (18) ◽  
pp. 1983-1992 ◽  
Author(s):  
M. B. Hocking ◽  
H. I. Bolker ◽  
B. I. Fleming
Keyword(s):  
Electron Spin Resonance ◽  
Electrode Potential ◽  
Radical Anion ◽  
Aqueous Alkaline Solution ◽  
Alkaline Pulping ◽  
Methanol Solutions ◽  
Spin Resonance ◽  
First Time ◽  
Reduced Forms ◽  
Esr Spectrometry

The radical anion of anthraquinone (AQ•−) has been generated by the reduction of anthraquinone (AQ) with sugars in aqueous alkaline solution. This appears to be the first time that the radical has been observed (esr spectrometry) in an entirely aqueous medium. Alkaline methanol solutions of AQ, when irradiated with light, yielded colourless solutions also exhibiting strong esr signals characteristic of. AQ•−.The ability of various carbohydrate and lignin preparations to reduce AQ, or to oxidize the reduced forms of AQ, was also investigated, both by direct observation and by electrode potential measurements. In very concentrated alkali, AQ was reduced by glucose to a green solid thought to be a quinhydrone.

Electron spin resonance detection of heterogeneous reactions of Pigment Red 122

1990 ◽  
Vol 68 (4) ◽  
pp. 640-643
Author(s):  
Mary Jane Walzak ◽  
John R. Harbour
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Radical Anion ◽  
Heterogeneous Reactions ◽  
Resonance Spectroscopy ◽  
G Factor ◽  
Spin Resonance ◽  
Two Component ◽  
Induced Signal ◽  
Resonance Detection

Electron spin resonance spectroscopy (ESR) has been used to investigate the electrochemical and photolytic behaviour of particulate C.I. Pigment Red 122. Heterogeneous electrochemical reduction and oxidation of the pigment resulted in different reversible ESR signals with the radical cation giving a signal of ΔHpp = 2.3 G and g-factor of 2.0033 and the radical anion giving ΔHpp = 3.2 G and g-factor 2.0039. On exposure to light the inherent ESR signal, which was determined to be a two-component signal, increased in intensity by a factor of 2.4 but did not change in linewidth or g-factor. This light-induced signal was reversible and decayed to initial levels in the dark. The mechanism of these reactions is discussed. Keywords: ESR, pigment, electrochemistry, photo effects.

scholarly journals ESR and Radiocarbon Dating of Gut Strings from Early Plucked Instruments

2020 ◽  
Vol 3 (1) ◽  
pp. 13 ◽  
Author(s):  
Sumiko Tsukamoto ◽  
Taro Takeuchi ◽  
Atsushi Tani ◽  
Yosuke Miyairi ◽  
Yusuke Yokoyama
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Signal Intensity ◽  
Radiocarbon Dating ◽  
Oxidized Iron ◽  
Spin Resonance ◽  
First Time ◽  
Great Revival

Early European plucked instruments have recently experienced a great revival, but a few aspects remain unknown (e.g., the gauge of gut strings). Here we report, for the first time, that the electron spin resonance (ESR) signal intensity of oxidized iron, Fe(III), from gut strings at g = 2 increases linearly with age within a few hundred years. The signal increase in the remaining old strings on early instruments can be used to judge if they are as old as or younger than the instrument. Obtaining the authenticity information of gut strings contributes to the revival of the old instruments and the music.

Notes: Thermal Lability of Membrane Proteins of Age Separated Erythrocytes as Studied by Electron Spin Resonance Spin Label Technique

1987 ◽  
Vol 42 (11-12) ◽  
pp. 1343-1344 ◽  
Author(s):  
Grzegorz Bartosz ◽  
Gabriele Christ ◽  
Harald Bosse ◽  
Roland Stephan ◽  
Helmut Gärtner
Keyword(s):  
Electron Spin Resonance ◽  
Membrane Proteins ◽  
Erythrocyte Membrane ◽  
Electron Spin ◽  
Spin Label ◽  
Thermal Denaturation ◽  
Spin Resonance ◽  
Resonance Spin ◽  
First Time ◽  
Erythrocyte Membrane Proteins

Thermal lability of bovine erythrocyte membrane proteins was studied by electron spin resonance using maleimide spin label. The temperature of the sample during measurements could be varied for the first time be­ tween 0 and 60 °C with an accuracy of ± 0.1 °C. Our results show that “old” erythrocyte membrane proteins are less stable against thermal denaturation then “young” cells.

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