The gas-phase photolysis of 2-methyl-1,3-butadiene at 123.6 nm

1984 ◽  
Vol 62 (9) ◽  
pp. 1731-1735
Author(s):  
Valerie I. Lang ◽  
Richard D. Doepker
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Sulfide ◽  
Gas Phase ◽  
Quantum Efficiency ◽  
Hydrogen Iodide ◽  
Quantum Yields ◽  
Primary Decomposition ◽  
Radical Scavengers ◽  
Molecule Reaction ◽  
Reaction Channels

The gas-phase photolysis of 2-methyl-1,3-butadiene has been investigated using krypton (123.6 nm) resonance radiation. The observed neutral products of the primary decomposition were vinylacetylene, ethylene, acetylene, methylacetylene, propylene, allene, 2-methy-1-buten-3-yne, pentatriene/1-penten-3-yne, 1,3-butadiene, 2-butyne and butatriene, listed in decreasing order of concentration. There was also evidence of the presence of several radical fragments: CH2/CH3, C2H3, C3H3, and C4H5. Quantum yields for each of the products were determined in the photolysis of 2-methyl-1,3-butadiene, performed both in the presence and the absence of additives. Nitric oxide and oxygen were employed as radical scavengers, while hydrogen sulfide and hydrogen iodide were used as radical interceptors. Twelve primary, neutral molecule, reaction channels were proposed and the quantum efficiency assigned for each. The ionization efficiency of 2-methyl-1,3-butadiene was established as n = 0.55 at 10.03 eV. No products formed exclusively via an ion–molecule pathway were identified and therefore the fate of the C5H8+ ion was not determined.

Gas-phase photolysis of spiropentane at 147.0 nm

1985 ◽  
Vol 63 (12) ◽  
pp. 3593-3596 ◽  
Author(s):  
M. Paller ◽  
R. D. Doepker
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Sulfide ◽  
Gas Phase ◽  
Hydrogen Iodide ◽  
Radical Scavenger ◽  
Relative Importance ◽  
Molecular Processes ◽  
Primary Reaction ◽  
Reaction Channels

The gas-phase photolysis of spiropentane has been investigated using xenon (147.0 nm) resonance radiation. Major products observed in order of decreasing importance are ethylene, aliène, methylacetylene, 1,2-butadiene, acetylene, propylene, and vinylacetylene. Nitric oxide was used as a radical scavenger while hydrogen sulfide and hydrogen iodide were employed as radical interceptors in the determination of the relative importance of radical and molecular processes. CH3/CH2 and CH3C=C• radicals were identified and quantified. Seven primary reaction channels were postulated of which those involving the "elimination" of ethylene were the most predominant accounting for 71% of the photodecomposition.

Vacuum-ultraviolet (147.0 nm and 123.6 nm) photolysis of 1,1-dimethylcyclopropane

1981 ◽  
Vol 59 (3) ◽  
pp. 537-542
Author(s):  
Joseph B. Binkewicz ◽  
Michael Kaplan ◽  
Richard D. Doepker
Keyword(s):  
Gas Phase ◽  
Vacuum Ultraviolet ◽  
Molecular Processes ◽  
Radical Scavengers ◽  
Primary Reaction ◽  
Radical Species ◽  
Molecule Reaction ◽  
Reaction Channels ◽  
A Charge ◽  
Photo Decomposition

The gas-phase photolysis of 1,1-dimethylcyclopropane has been investigated using xenon (147.0 nm) and krypton (123.6 nm) resonance radiation. Major products observed in order of decreasing importance were isobutene, ethylene, hydrogen, 1,3-butadiene 2-methyl-1,3-butadiene, propylene, allene, methylacetylene, and acetylene. Radical scavengers, NO and O2, and radical interceptors, H2S/D2S and HI, were used to determine the relative importance of radical and molecular processes. CH3, C2H3, C3H5, and C4H7 radical species were identified and quantified. Ten primary reaction channels were postulated, of which the elimination of methylene was the most predominant, accounting for 34% of the photo-decomposition at 147.0 nm and 39% at 123.6 nm. Although ionization was established at 123.6 nm (η = 0.10) the nature of a charge transfer or other ion-molecule reaction channel leading to the formation of 2-methyl-1-butene and 2-methyl-2-butene could not be determined.

Wilzbach Tritation studies. III. A study of physical variables affecting exchange in the polycyclic aromatics

1967 ◽  
Vol 20 (9) ◽  
pp. 1875 ◽  
Author(s):  
JL Garnett ◽  
SW Law
Keyword(s):  
Nitric Oxide ◽  
Gas Phase ◽  
Polycyclic Hydrocarbon ◽  
Simple Relationship ◽  
Polycyclic Aromatics ◽  
Radical Scavengers ◽  
Effect Of Particle Size ◽  
Labelling Process ◽  
Physical Variables ◽  
Radical Processes

The effect of particle size of substrate and tritium gas pressure on the efficiency of Wilzbach tritiation of crystalline polycyclic hydrocarbons has been investigated. The hydrocarbons studied included naphthalene, biphenyl, phenanthrene, chrysene, pyrene, m- and p-terphenyls, and acridine. No simple relationship between ionization potential and tritium incorporation was observed. The effect of radical scavengers such as nitric oxide and moderators such as helium on the labelling process have been examined. Tritium incorporation in a polycyclic hydrocarbon is enhanced lf gas exposure occurs in the presence of benzoic acid. The results are discussed in terms of current theories proposed for tritium labelling based on gas-phase studies. In the condensed phase present data show that radical processes are important in Wilzbach labelling. This has been confirmed by a preliminary e.s.r. examination of naphthalene and anthracene in the presence of tritium gas.

CHANGES OF NITRIC OXIDE SYNTHASE AND HYDROGEN SULFIDE IN BLOOD LYMPHOCYTES IN THE ACUTE PERIOD OF POLYTRAUMA

2019 ◽  
Vol 72 (8) ◽  
pp. 1473-1476
Author(s):  
Nataliya Matolinets ◽  
Helen Sklyarova ◽  
Eugene Sklyarov ◽  
Andrii Netliukh
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Sulfide ◽  
Tissue Injury ◽  
Traumatic Injury ◽  
Cell Types ◽  
No Synthase ◽  
Septic Complications ◽  
Acute Period ◽  
Gaseous Transmitters ◽  
The Moment

Introduction: Polytrauma patients have high risk of shock, septic complications and death during few years of follow-up. In recent years a lot of attention is paid to gaseous transmitters, among which are nitrogen oxide (NO) and hydrogen sulfide (H2S). It is known that the rise of NO and its metabolites levels occurs during the acute period of polytrauma. Nitric oxide and hydrogen sulfide are produced in different cell types, among which are lymphocytes. The aim: To investigate the levels of NO, NOS, iNOS, еNOS, H2S in lymphocytes lysate in patients at the moment of hospitalization and 24 hours after trauma. Materials and methods: We investigated the levels of NO, NO-synthase, inducible NO-synthase, endothelial NO-synthase, H2S in lymphocytes lysate in patients at the moment of hospitalization and 24 hours after trauma. Results: The study included 20 patients with polytrauma who were treated in the intensive care unit (ICU) of the Lviv Emergency Hospital. Tissue injury was associated with an increased production of NO, NOS, iNOS, еNOS during the acute period of polytrauma. At the same time, the level of H2S decreased by the end of the first day of traumatic injury. Conclusions: In acute period of polytrauma, significant increasing of iNOS and eNOS occurs with percentage prevalence of iNOS over eNOS on the background of H2S decreasing.

The Role of Reactive Oxygen Species, Kinases, Hydrogen Sulfide, and Nitric Oxide in the Regulation of Autophagy and Their Impact on Ischemia and Reperfusion Injury in the Heart

2020 ◽  
Vol 16 ◽  
Author(s):  
Andrey Krylatov ◽  
Leonid Maslov ◽  
Sergey Y. Tsibulnikov ◽  
Nikita Voronkov ◽  
Alla Boshchenko ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Hydrogen Sulfide ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Ischemia And Reperfusion ◽  
Oxygen Species ◽  
Ischemia And Reperfusion Injury ◽  
Adaptive Process

: There is considerable evidence in the heart that autophagy in cardiomyocytes is activated by hypoxia/reoxygenation (H/R) or in hearts by ischemia/reperfusion (I/R). Depending upon the experimental model and duration of ischemia, increases in autophagy in this setting maybe beneficial (cardioprotective) or deleterious (exacerbate I/R injury). Aside from the conundrum as to whether or not autophagy is an adaptive process, it is clearly regulated by a number of diverse molecules including reactive oxygen species (ROS), various kinases, hydrogen sulfide (H2S) and nitric oxide (NO). The purpose this review is to address briefly the controversy regarding the role of autophagy in this setting and to examine a variety of disparate molecules that are involved in its regulation.

Hydrogen Sulfide in Physiological and Pathological Mechanisms in Brain

2018 ◽  
Vol 17 (9) ◽  
pp. 654-670 ◽  
Author(s):  
Mohit Kumar ◽  
Rajat Sandhir
Keyword(s):  
Nitric Oxide ◽  
Traumatic Brain Injury ◽  
Hydrogen Sulfide ◽  
Neurodegenerative Disorders ◽  
Neurological Disorders ◽  
Scientific Community ◽  
Molecular Targets ◽  
Long Term Potentiation ◽  
Term Potentiation

Background & Objective: Hydrogen sulfide [H2S] has been widely known as a toxic gas for more than 300 years in the scientific community. However, the understanding about this small molecule has changed after the discovery of involvement of H2S in physiological and pathological mechanisms in brain. H2S is a third gasotransmitter and neuromodulator after carbon monoxide [CO] and nitric oxide [NO]. H2S plays an important role in memory and cognition by regulating long-term potentiation [LTP] and calcium homeostasis in neuronal cells. The disturbances in endogenous H2S levels and trans-sulfuration pathway have been implicated in neurodegenerative disorders like Alzheimer’s disease, Parkinson disease, stroke and traumatic brain injury. According to the results obtained from various studies, H2S not only behaves as neuromodulator but also is a potent antioxidant, anti-inflammatory and anti-apoptotic molecule suggesting its neuroprotective potential. Conclusion: Recently, there is an increased interest in developing H2S releasing pharmaceuticals to target various neurological disorders. This review covers the information about the involvement of H2S in neurodegenerative diseases, its molecular targets and its role as potential therapeutic molecule.

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