scholarly journals Assessing dimerisation degree and cooperativity in a biomimetic small-molecule model by pulsed EPR

2015 ◽  
Vol 51 (25) ◽  
pp. 5257-5260 ◽  
Author(s):  
K. Ackermann ◽  
A. Giannoulis ◽  
D. B. Cordes ◽  
A. M. Z. Slawin ◽  
B. E. Bode

Pulsed electron paramagnetic resonance (EPR) spectroscopy is used for titrating spin-labelled terpyridine with Zn(ii)-solution to study complex formation. This system can serve as a small-molecule model system for tuneable dimerisation.

2015 ◽  
Vol 119 (25) ◽  
pp. 6641-6649 ◽  
Author(s):  
Andrei V. Astashkin ◽  
Li Chen ◽  
Bradley O. Elmore ◽  
Deepak Kunwar ◽  
Yubin Miao ◽  
...  

2015 ◽  
Vol 98 (4) ◽  
pp. 866-870 ◽  
Author(s):  
Violetta Kozik ◽  
Krystyna Jarzembek ◽  
Agnieszka Jędrzejowska ◽  
Andrzej Bąk ◽  
Justyna Polak ◽  
...  

Abstract Pomegranate fruit (Punica granatum L.) is a source of numerous phenolic compounds, and it contains flavonoids such as anthocyanins, anthocyanidins, cyanidins, catechins and other complexes of flavonoids, ellagitannins, and hydrolyzed tannins. Pomegranate juice shows antioxidant, antiproliferative, and anti-atherosclerotic properties. The antioxidant capacity (TEAC) of the pomegranate juices was measured using electron paramagnetic resonance (EPR) spectroscopy and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) as a source of free radicals, and the total phenolic (TP) content was measured using UV-Vis spectroscopy. All the examined pomegranate juices exhibited relatively high antioxidant properties. The TEAC values determined by means of EPR spectroscopy using Trolox (TE) as a free radical scavenger were in the range of 463.12 to 1911.91 μmol TE/100 mL juice. The TP content measured by the Folin-Ciocalteu method, using gallic acid (GA) as a free radical scavenger, widely varied in the investigated pomegranate juice samples and ranged from 1673.62 to 5263.87 mg GA/1 L juice. The strongest antioxidant properties were observed with the fresh pomegranate juices obtained from the fruits originating from Israel, Lebanon, and Azerbaijan. Correlation analysis of numerical data obtained by means of EPR spectroscopy (TEAC) and UV-Vis spectroscopy (TP) gave correlation coefficient (r) = 0.90 and determination coefficient (r2) = 0.81 (P <0.05).


2002 ◽  
Vol 15 (1) ◽  
pp. 37-46 ◽  
Author(s):  
George A. Rinard ◽  
Richard W. Quine ◽  
Gareth R. Eaton ◽  
Sandra S. Eaton

2015 ◽  
Vol 17 (31) ◽  
pp. 20331-20337 ◽  
Author(s):  
Marat Gafurov ◽  
Timur Biktagirov ◽  
Georgy Mamin ◽  
Elena Klimashina ◽  
Valery Putlayev ◽  
...  

The interplay of oppositely charged substitutions in the structure of hydroxyapatite nanopowders is investigated by pulsed electron paramagnetic resonance and ab initio density functional theory calculations.


1978 ◽  
Vol 175 (3) ◽  
pp. 955-957 ◽  
Author(s):  
D J Lowe

The e.p.r. spectra of the Fe-proteins of nitrogenase from all sources studied have unusual features in that they have very anisotropic linewidths and low integrated intensities. These characteristics can be explained by assuming that one of the two electrons accepted by these proteins is located at a rapidly relaxing paramagnetic centre that is unobservable by e.p.r., but causes anisotropic broadening of the e.p.r. signal of the other electron. Complex-formation between Fe-proteins and MgATP is described in terms of a 50-60 degrees rotation of the e.p.r.-observable centre.


Author(s):  
V. V. Ptushenko

This article describes the formation of the chemical electron paramagnetic resonance (EPR) spectroscopy institute established by Academician Vladislav V. Voevodsky (1917–1967) along with the history of the development of the instrumentation basis for this field of science in the Union of Soviet Socialist Republics (USSR). The design of the first EPR spectrometers for the chemical radio spectroscopy initiated the emergence of a new scientific instrumentation field in this country. Based on recollections shared by scientists and engineers and an examination of archive materials, the author reconstructs relevant events and identifies major participants in this process.


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