A new perspective of the chemistry and kinetics of inactivation of COVID -19 coronavirus aerosols

In this paper we present a new approach to the mechanism of inactivation of enveloped virus aerosols. The analysis is in terms of oxidation of the lipid bilayer of the viral envelope through a free radical chain reaction. The rate kinetics of the process for various enveloped viruses have been compared and the indications are that the inactivations are closely related. Promoting virus inactivation with UV light is briefly reviewed and discussed as an extension of the chain reaction mechanism, which with physicochemical analyses give insights into the process and of reaction complexities. An outline of a practical method of achieving a 3-log10 level of deactivation in 1 min is described with purified air being returned to healthcare environments.

The discovery of new phloroglucinol glycosides from Agrimonia pilosa and the mechanism of oxidative dearomatization of the methyl-substituted phloroglucinol derivatives

New phloroglucinol glycosides, aglycones, and oxidative dearomatized products of aglycones were discovered from Agrimonia pilosa, and the mechanism of the auto oxidative dearomatization was disclosed as a free radical chain reaction with 3O2.

Direct targets and subsequent pathways for molecular hydrogen to exert multiple functions: Focusing on interventions in radical reactions.

: Molecular hydrogen (H2 ) was long regarded as non-functional in mammalian cells. We overturned the concept by demonstrating that H2 exhibits antioxidant effects and protects cells against oxidative stress. Subsequently, it has been revealed that H2 has multiple functions in addition to antioxidant effects, including ant-inflammatory, anti-allergic functions, and as a cell death and autophagy regulation. Additionally, H2 stimulates energy metabolism. Because H2 does not readily react with most biomolecules without a catalyst, it is essential to identify the primary targets with which H2 reacts or interacts directly. As a first event, H2 may react directly with strong oxidants such as hydroxyl radicals (•OH) in vivo. This review addresses the key issues related to this in vivo reaction. •OH may have a physiological role because it triggers a free radical chain reaction and may be involved in the regulation of Ca2+ - or mitochondrial ATP-dependent K+ - channeling. In the subsequent pathway, H2 suppressed a free radical chain reaction, leading to decreases in lipid peroxide and its end products. Derived from the peroxides, 4-hydroxy-2-nonenal functions as a mediator that up-regulates multiple functional PGC-1α. As the other direct target in vitro and in vivo, H2 intervenes in the free radical chain reaction to modify oxidized phospholipids, which may act as an antagonist of Ca2+ -channels. The resulting suppression of Ca2+ - signaling inactivates multiple functional NFAT and CREB transcription factors, which may explain H2 multifunctionality. This review also addresses the involvement of NFAT in the beneficial role of H2 in COVID-19, Alzheimer’s disease and advanced cancer. We discuss some unsolved issues of H2 action on lipopolysaccharide signaling, MAPK and NF-κB pathways and the Nrf2 paradox. Finally, as a novel idea for the direct targeting of H2 , this review introduces the possibility that H2 causes structural changes in proteins via hydrate water changes.

Effects of N2 and 1,1,1,3,3,3-Hexafluoropropane (C3H2F6) on Inhibition of Coal Flames

Two gaseous fire-extinguishing agents, N2 and C3H2F6, were used to suppress open-flame coal combustion, and their inhibitory effects as well as the corresponding mechanisms were probed by simulations and confined-space experiments. The influence of N2 on the flame surface area linearly increased with increasing N2 concentration, while a sudden increase in reduction was observed from C3H2F6. In addition, C3H2F6 was capable of inducing well-pronounced flame flash-off and featured an extinguishing time smaller than that of N2, thus being a more efficient extinguishing agent. The above findings were rationalized by numerical simulations, which revealed that whereas N2 extinguished the flame mainly by dilution of reactive intermediates, C3H2F6 decomposed to produce F-containing species that competed with coal for OH, H, and O free radicals and thus cut off the free-radical chain reaction.

Inhibiting oxidation and enhancing absorption characteristics of sodium sulfite for SO2 removal from the non-ferrous smelting flue gas

In this work, we investigated the absorption characteristics of SO2 and the effect of inhibitors on the desulfurization performances of Na2SO3. The results showed that the NO2 had a competitive effect with SO2 on SO32- which resulted in a significant decrease in the absorption capacity of SO2. O2 in the flue gas could decrease the absorption capacity of SO2 due to the oxidation of Na2SO3. Besides, Na2S2O3 had more excellent inhibiting effect on the oxidation of SO32-; the inhibition mechanism is understood on the basis of the free radical chain reaction, whereby S2O32- combined with the sulfite free radical to form an inert substance, thus, quenching the reaction of free radical with the dissolved oxygen and invariably inhibiting the oxidation of SO32-. Furthermore, the intrinsic and the apparent oxidation kinetics of Na2SO3 oxidation process with Na2S2O3 were investigated to explain the relationships between consumption rates of SO32- and the absorption capacities of SO2 under different components in flue gas and absorption solution.

Evidence that Criegee intermediates drive autoxidation in unsaturated lipids

Autoxidation is an autocatalytic free-radical chain reaction responsible for the oxidative destruction of organic molecules in biological cells, foods, plastics, petrochemicals, fuels, and the environment. In cellular membranes, lipid autoxidation (peroxidation) is linked with oxidative stress, age-related diseases, and cancers. The established mechanism of autoxidation proceeds via H-atom abstraction through a cyclic network of peroxy–hydroperoxide-mediated free-radical chain reactions. For a series of model unsaturated lipids, we present evidence for an autoxidation mechanism, initiated by hydroxyl radical (OH) addition to C=C bonds and propagated by chain reactions involving Criegee intermediates (CIs). This mechanism leads to unexpectedly rapid autoxidation even in the presence of water, implying that as reactive intermediates, CI could play a much more prominent role in chemistries beyond the atmosphere.

Study on the Mechanism of Cold and Negative Temperature Coefficient in Natural Process of Gasoline Hydrocarbon

In this paper, the stoichiometric mechanism of gas phase oxidation process of gasoline hydrocarbons was studied through using theoretical stoichiometry. The reason of the phenomenon of cold flame and negative temperature coefficient in the reaction of hydrocarbon molecules before the flame was explained from the molecular level. During the gas phase oxidation process, the alkoxy radical RO· reacts with hydroxyl ·OH to form a relatively stable intermediate such as aldehyde (or ketone) and H2O molecules, and the free radical chain reaction process.The temperature of the reaction process is very low, while the release of a large number of heat, the formation of aldehydes (or ketones) from the excited state back to the ground state when the emission of about 400nm wavelength of light blue fluorescence.

Coal Spontaneous Combustion Mechanism and Research of New Flame Retardant Material

According to analyzing the mechanism coal of spontaneous combustion,Concluded three ways for the prevention and control of coal spontaneous combustion: (1) the elimination of heat accumulation; (2) reduce the oxygen concentration; (3) the blocking free radical chain reaction; And based on the mechanism of flame retardant summarized the types of the inhibitor agent and the inhibitor agent resistance effect, this paper briefiy introduces the research status of the inhibitor agent, and points out the problems existing in the flame retardant materials, put forward material selection problens of a new flame retardant materials and research direction in the future.