Heterogeneous chain propagation in a rarefied oxyhydrogen flame

2004 ◽  
Vol 399 (4) ◽  
pp. 298-301
Author(s):  
E. N. Aleksandrov ◽  
S. N. Kozlov
Keyword(s):  
Chain Propagation ◽  
Heterogeneous Chain ◽  
Oxyhydrogen Flame ◽  
Heterogeneous Chain Propagation

Heterogeneous chain propagation on a quartz surface

2006 ◽  
Vol 42 (3) ◽  
pp. 282-291 ◽  
Author(s):  
E. N. Aleksandrov ◽  
S. N. Kozlov ◽  
N. M. Kuznetsov
Keyword(s):  
Chain Propagation ◽  
Quartz Surface ◽  
Heterogeneous Chain ◽  
Heterogeneous Chain Propagation

Sulfamides Direct Radical-Mediated Chlorination of Aliphatic C–H Bonds

2019 ◽  
Author(s):  
Melanie Short ◽  
Mina Shehata ◽  
Matthew Sanders ◽  
Jennifer Roizen
Keyword(s):  
Hydrogen Atom ◽  
Transfer Reaction ◽  
Hydrogen Atom Transfer ◽  
Chain Propagation ◽  
Propagation Mechanism ◽  
Atom Transfer ◽  
Radical Chain ◽  
Radical Intermediates ◽  
Transfer Processes ◽  
Unusual Position

Sulfamides guide intermolecular chlorine transfer to gamma-C(sp<sup>3</sup>) centers. This unusual position-selectivity arises because accessed sulfamidyl radical intermediates engage in otherwise rare 1,6-hydrogen-atom transfer processes. The disclosed chlorine-transfer reaction relies on a light-initiated radical chain-propagation mechanism to oxidize C(sp<sup>3</sup>)-H bonds.

Sulfamides Direct Radical-Mediated Chlorination of Aliphatic C–H Bonds

2019 ◽  
Author(s):  
Melanie Short ◽  
Mina Shehata ◽  
Matthew Sanders ◽  
Jennifer Roizen
Keyword(s):  
Hydrogen Atom ◽  
Transfer Reaction ◽  
Hydrogen Atom Transfer ◽  
Chain Propagation ◽  
Propagation Mechanism ◽  
Atom Transfer ◽  
Radical Chain ◽  
Radical Intermediates ◽  
Transfer Processes ◽  
Unusual Position

Sulfamides guide intermolecular chlorine transfer to gamma-C(sp<sup>3</sup>) centers. This unusual position-selectivity arises because accessed sulfamidyl radical intermediates engage in otherwise rare 1,6-hydrogen-atom transfer processes. The disclosed chlorine-transfer reaction relies on a light-initiated radical chain-propagation mechanism to oxidize C(sp<sup>3</sup>)-H bonds.

scholarly journals XIX. On the photographic arc spectrum of iron meteorites

1894 ◽  
Vol 185 ◽  
pp. 1023-1028
Keyword(s):  
Royal Society ◽  
Solar Spectrum ◽  
British Museum ◽  
Iron Meteorites ◽  
Electrolytic Iron ◽  
Comparison Spectrum ◽  
Size And Shape ◽  
Previous Communication ◽  
Oxyhydrogen Flame ◽  
Made In

In a communication to the Royal Society in 1887, I gave an account of certain experiments which I had made in connection with the spectra of various meteorites at various temperatures. The spectra were observed at the temperature of the oxyhydrogen flame and the electric spark without jar, and when glowed in vacuum tubes. Some larger specimens of the iron meteorites, Nejed and Obernkirchen, cut so that they were of a size and shape suitable for forming the poles of an arc lamp, having afterwards been kindly placed at my disposal by the Trustees of the British Museum, it became possible to study the arc spectra of these meteorites under very favourable conditions, all impurities introduced by the use of the carbon poles being thus avoided. The region of the spectrum photographed extends from K to D, in the case of each meteorite, and in addition to the solar spectrum, that of electrolytic iron, prepared by Professor Roberts-Austen, referred to in a previous communication, has been used as a comparison spectrum in one case.

Mechanisms involved in the protective effect of estradiol-17β on lipid peroxidation and DNA damage

1998 ◽  
Vol 274 (6) ◽  
pp. E1002-E1008 ◽  
Author(s):  
Stacey Ayres ◽  
William Abplanalp ◽  
James H. Liu ◽  
M. T. Ravi Subbiah
Keyword(s):  
Hydrogen Peroxide ◽  
Lipid Peroxidation ◽  
Dna Damage ◽  
Superoxide Radical ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Chain Propagation ◽  
Similar Degree ◽  
Estradiol 17Β ◽  
Ros Scavengers

Previous studies from our laboratory have shown that estrogens can protect against lipoprotein peroxidation and DNA damage. In this study, the mechanism of estradiol-17β (E2) action was investigated by comparing E2 with selective scavengers of reactive oxygen species (ROS) in terms of inhibition of 1) human low-density lipoprotein (LDL) peroxidation (measured by the diene conjugation method) and 2) DNA damage (measured by the formation of strand breaks in supercoiled OX-174 RFI DNA). In addition, the direct effect of E2 on the generation of individual ROS was also measured. By use of ROS scavengers, it was determined that lipoprotein peroxidation was predominantly due to superoxide (39%), with some contributions from hydrogen peroxide (23%) and peroxy (38%) radicals. E2 was a more effective inhibitor of peroxidation than all the ROS scavengers combined. In DNA damage, scavengers of hydrogen peroxide, hydroxyl, and superoxide radical offered significant protection (49–65%). E2 alone offered a similar degree of protection, and no additional effect was evident when it was combined with ROS scavengers. E2caused a significant reduction (37%) in the production of superoxide radical by bovine heart endothelial cells in culture but had no effect on the formation of either hydrogen peroxide or hydroxyl radicals. These studies show that 1) the protection offered by E2 in terms of lipid peroxidation could be due to its ability to inhibit generation of superoxide radical and prevent further chain propagation, and 2) in DNA damage protection, E2 mainly appears to inhibit chain propagation.

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