ESR spectra of micellar aqueous solutions of the dodecyl sulfates of 2,2,6,6-tetramethyl-4-ammoniumpiperidin-1-oxyl and Mn2+

1977 ◽  
Vol 26 (12) ◽  
pp. 2523-2526
Author(s):  
E. E. Zaev ◽  
Yu. G. Grechishnikov ◽  
L. V. Spirikhin
Keyword(s):  
Aqueous Solutions ◽  
Esr Spectra

Detection of Semiquinone Radicals of N-Acylcatecholamines in Aqueous Solution

1985 ◽  
Vol 40 (7-8) ◽  
pp. 535-538 ◽  
Author(s):  
Martin G. Peter ◽  
Hartmut B. Stegmann ◽  
Hoang Dao-Ba ◽  
Klaus Scheffler
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Esr Spectra ◽  
Semiquinone Radicals ◽  
Spin Stabilization ◽  
Michael Type Addition ◽  
Nitrogen Nucleophiles

Abstract ESR-spectra were recorded during the oxidation of N-acetyldopamine and N-β-alanyldopamine in aqueous solutions. Semiquinone radicals were detected under conditions of spin stabilization by Zn2+ ions. The appearance of the spectra was the same in the presence or in the absence of proteins. No evidence was obtained for the formation of products that could have arisen eventually from intermolecular Michael-type addition of nitrogen nucleophiles.

Spin trapping of radicals formed during radiolysis of aqueous solutions. Direct electron spin resonance observations

1976 ◽  
Vol 54 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Frederick Peter Sargent ◽  
Edward Michael Gardy
Keyword(s):  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
Electron Spin ◽  
Direct Observation ◽  
Electron Accelerator ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Spin Resonance

It is shown that esolv, H•, and OH formed by the radiolysis of water by 3 MeV electrons are trapped by nitroso and nitrone compounds to give nitroxides with well defined esr spectra. Three spin trapping agents were used, nitroso-t-butane, phenyl-t-butyl nitrone, and 5,5′-dimethyl pyrroline-1-oxide. The latter was shown to be an excellent compound for these studies. Complications due to the instability of some of the nitroxides were overcome by coupling the electron accelerator to the esr spectrometer to permit direct observation of the spectra.

Spin trapping of the azide radical with nitroso compounds

1982 ◽  
Vol 60 (12) ◽  
pp. 1597-1597 ◽  
Author(s):  
Walter Kremers ◽  
Grant W Koroll ◽  
Ajit Singh
Keyword(s):  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
Hydroxyl Radicals ◽  
Electron Spin ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Nitroso Compounds ◽  
Spin Traps ◽  
Spin Resonance

Azide radicals (N3·) are formed in aqueous solutions by the reaction of hydroxyl radicals (·OH) with azide anions (N3aq−). Azide radicals have been spin trapped with three nitroso spin traps: nitrosodurene (ND), 2,6-dideutero-3,5-dibromo-4-nitrosobenzene sulfonate (DDNBS), and 2-methyl-2-nitrosopropane (MNP). The electron spin resonance (esr) spectra show the presence of two molecules of the spin traps in the spin-trapped species.

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

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