Electrochemical Behavior of (Zn, Mn)-Al Nitrated Hydrotalcites

2012 ◽  
Vol 15 (4) ◽  
pp. 301-306 ◽  
Author(s):  
Alvaro Sampieri ◽  
Jorge Vázquez-Arenas ◽  
Ignacio González ◽  
Geolar Fetter ◽  
Heriberto Pfeiffer ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Lamellar Structure ◽  
Oxidation Process ◽  
Reduction Process ◽  
The Other ◽  
Oxidation Processes ◽  
Reduction Processes ◽  
Oxidation Reduction ◽  
Alkaline Conditions ◽  
Continuous Oxidation

The electrochemical behavior of synthetic binary, Zn-Al and Mn-Al, and ternary (Zn-Mn)-Al hydrotalcites (HT) was studied by cyclic voltammetry in alkaline conditions (pH≡12). The Zn-Al HT characterization revealed two irreversible and continuous oxidation processes: i) Zn0|Zn2+ and ii) Zn0|ZnO. On the other hand, the binary HT containing Mn presented a reversible behavior for the oxidation-reduction process Mn4+|Mn3+. The same oxidation-reduction processes were observed in the ternary HT. However, variations in the reduction-oxidation process were detected by XRD for the ternary HT as a result of spinel formation. These results could also be influenced due to a higher accessibility of manganese in HT since the morphology of hydrotalcite (lamellar structure) provides a regular distribution of Mn atoms interacting with Zn atoms through hydroxyl bridges.

Plasma Oxidation Process of Silicon Surfaces Investigated by Infrared Spectroscopy

2005 ◽  
Vol 8 (1) ◽  
Author(s):  
Masanori Shinohara ◽  
Teruaki Katagiri ◽  
Keitaro Iwatsuji ◽  
Yoshinobu Matsuda ◽  
Yasuo Kimura ◽  
...  
Keyword(s):  
Oxygen Plasma ◽  
Oxidation Process ◽  
The Other ◽  
Silicon Surfaces ◽  
Infrared Absorption Spectroscopy ◽  
Oxygen Species ◽  
Plasma Oxidation ◽  
Oxidation Processes ◽  
Surface Hydrogen ◽  
Stretching Vibration

AbstractPlasma oxidation processes of hydrogen-terminated Si(100), (110), and (111) surfaces are investigated by infrared absorption spectroscopy (IRAS) in multiple internal reflection (MIR) geometry. We measured IRAS spectra of hydrogen-terminated Si surfaces exposed to oxygen-plasma in the Si-H stretching vibration region. IRAS data demonstrated that oxygen-plasma affects two influences on the Si surfaces; one is that oxygen-plasma removes surface hydrogen to oxidize the Si surfaces. The other is that it forces the hydrogen into the subsurface regions where oxygen species cannot reach. The former effect does not depend on the crystal graphic orientations, but the latter depends on it. Therefore, in order to oxidize perfectly the H-terminated Si surfaces using oxygen-plasma, the sample surfaces need to be heated so that oxygen atoms can diffuse into the subsurface regions.

scholarly journals THE FORMATION OF METHEMOGLOBIN BY STREPTOCOCCUS VIRIDANS

1916 ◽  
Vol 24 (4) ◽  
pp. 315-327 ◽  
Author(s):  
Francis G. Blake
Keyword(s):  
Blood Cells ◽  
Chemical Nature ◽  
Oxidation Process ◽  
Streptococcus Viridans ◽  
Bacterial Cells ◽  
Active Oxidation ◽  
Oxidation Processes ◽  
Reduction Processes ◽  
Methemoglobin Formation ◽  
Metabolic Activities

Cultures of Streptococcus viridans when brought into contact with red blood corpuscles have the power of transforming oxyhemoglobin into methemoglobin. The reaction occurs only in the presence of living streptococci when they are able to carry on their metabolic activities. The intensity of the reaction runs roughly parallel with the period of growth and multiplication of the bacteria and gradually diminishes and disappears as growth ceases. There is no apparent relation between the activity of a given strain of Streptococcus viridans in producing methemoglobin and its source or virulence. If the streptococci are suspended in salt solution they are unable to change oxyhemoglobin into methemoglobin unless some nutrient substance is present. Of the various nutrient substances tested dextrose is the most efficient in enabling the organisms to bring about the reaction. The reaction does not occur in the absence of oxygen, and is retarded by an excess of oxygen. Substances which tend to reduce the metabolic activities of the bacteria to a minimum exert an inhibitory action on methemoglobin formation. While not definitely proving it to be so, the results obtained in the above experiments strongly support the supposition that the reaction is not due to injurious substances produced by the bacteria or to products arising from the decomposition of the nutrient material present, but rather to the metabolic activities of the bacteria themselves when they are surrounded by environmental conditions which render growth and multiplication possible. The exact chemical nature of the change of oxyhemoglobin to methemoglobin is not known, but it is probably an oxidation process or a combination of reduction and oxidation processes, as pointed out by Heubner. As Cole has shown, the action of aminophenol is of great interest in this connection, in that it acts like a catalytic agent in being able to transform much more hemoglobin into methemoglobin than would be possible if the reaction were a simple molecular one. The metabolic activities of bacteria are largely in the nature of oxidation and reduction processes. The transformation of oxyhemoglobin into methemoglobin by streptococci of the viridans type, therefore, may be analogous to the action of such substances as aminophenol, and the reaction may be due to the active oxidation and reduction processes occurring in the neighborhood of the bacterial cells. The failure of the reaction to occur in the absence of oxygen and its retardation in the presence of an excess of oxygen, both with streptococci and with pneumococci (Cole) would seem to support this theory. Such results, however, may be due to the abnormal conditions surrounding the bacteria with consequent inhibition of their metabolic activities. Cole concluded as the result of his study of methemoglobin formation by pneumococci that since bacteria may injure red blood cells apparently by disturbances in oxidation in the immediate neighborhood of the organisms rather than by the production of a definite toxin, it is possible that bacteria may injure other tissue cells in a like manner and that the pathological effects produced by these bacteria may be explained on this basis. The experimental results recorded above have shown that the formation of methemoglobin by Streptococcus viridans in no way differs from its formation by pneumococci, and they lend support to the theory that bacteria may be injurious to tissues because of the disturbances in oxidation brought about by the metabolic activities of the organisms, especially those associated with growth and multiplication. It is believed that this theory may be particularly applicable to the pathological effects caused by Streptococcus vindans because the lesions produced by it, whether single or multiple, both in man and in experimental animals, are prone to be localized and associated with the actual presence of the streptococci in the lesions.

Formation Characteristics of Formaldehyde and the Formaldehyde Precursors Which Release Formaldehyde through Thermal Decomposition in Water

1992 ◽  
Vol 25 (11) ◽  
pp. 371-378
Author(s):  
H. Yamada ◽  
S. Matsui
Keyword(s):  
Thermal Decomposition ◽  
Surface Water ◽  
Oxidation Process ◽  
Algal Growth ◽  
The Other ◽  
Culture Solution ◽  
Growth Cycles ◽  
Blue Green Algae ◽  
Oxidation Processes ◽  
Chemical Structures

The amount of formaldehyde (FA) in surface water and the amount of FA formed by boiling the water were analyzed. Formation characteristics of FA and of the formaldehyde precursors which release FA through thermal decomposition (FA-PTDs), in surface water and the culture solution of blue-green algae (Phormidiumtenue and Anabaenamacrospora), were investigated. The characteristics by ozonation were also investigated. FA is released by the artificial oxidation process such as ozonation and by thermal decomposition. It is also released from a natural oxidation process in lake water during algal growth cycles. However, FA and FA-PTDs are biodegradable and do not last long in water. At present, it is not clear what kind of chemical structures FA-PTDs have. In general, FA-PTDs are different from the other formaldehyde precursors which form FA through artificial oxidation processes such as chlorination and ozonation. However, it is indicated that there is a certain type of FA-PTDs which can also be a formaldehyde precursor which easily forms FA by oxidation.

scholarly journals On the mechanism of oxidation-reduction potential

1927 ◽  
Vol 101 (707) ◽  
pp. 57-70 ◽  
Keyword(s):  
Reduction Potential ◽  
Reduction Process ◽  
Point Of View ◽  
Biological Oxidation ◽  
Hydrogen Atoms ◽  
Oxidation Processes ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
The Subject ◽  
Mechanism Of Oxidation

The phenomena of oxidation-reduction potential are becoming increasingly important in the study of biological oxidation processes. Unfortunately, however, the application of the results obtained from studies on potential to such processes has been somewhat hindered by the fact that the study of potential phenomena has up to the present been approached from a point of view which differs considerably from that of the more important theories of the mechanism of biological oxidation processes. The conceptions used in the development of the two subjects have been different, and the close connection between the two sets of phenomena has thereby been obscured. For instance, Wieland’s theory, which has played such an important part in the development of the subject of biological oxidation processes, is founded on the conception of activation and transfer of hydrogen atoms, while Mansfield Clark, in his recent important and valuable studies on reduction-potential, makes use of conceptions such as electron activity, transfer of “ electron pairs,” and so on. This absence of “ linking up ” between the two sides of the subject has, in fact, been brought up as an objection to the Wieland view. For instance, Clark (3, 4) claims that the reduction-potential phenomena prove that the oxidation-reduction process consists essentially in the transfer of an electron pair from reductant to oxidant, and not in the transfer of hydrogen as assumed by Wieland. He regards this as a very serious objection to the Wieland theory, although possibly not sufficient entirely to disprove it. It must be pointed out, however, that the fact that the electron transfer hypothesis leads to correct results is no proof of its truth until the alternative hypotheses have been shown to yield incorrect results. In the present communication it is shown that the Wieland view also leads to correct results ; in fact, it is possible to predict the reduction-potential phenomena from the work of Wieland. This at once disposes of one of the main objections to Wieland’s theory and renders it possible to relate the mechanism of oxidation-reduction potential with that of biological oxidation-reduction processes.

scholarly journals Transcriptome analysis of chloride intracellular channel knockdown in Drosophila identifies oxidation-reduction function as possible mechanism of altered sensitivity to ethanol sedation

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0246224
Author(s):  
Rory M. Weston ◽  
Rebecca E. Schmitt ◽  
Mike Grotewiel ◽  
Michael F. Miles
Keyword(s):  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Reduction Process ◽  
Major Influence ◽  
Biological Processes ◽  
Ethanol Sensitivity ◽  
Substantial Impact ◽  
Reduction Processes ◽  
Oxidation Reduction ◽  
Acute Ethanol

Chloride intracellular channels (CLICs) are a unique family of evolutionarily conserved metamorphic proteins, switching between stable conformations based on redox conditions. CLICs have been implicated in a wide variety biological processes including ion channel activity, apoptosis, membrane trafficking, and enzymatic oxidoreductase activity. Understanding the molecular mechanisms by which CLICs engage in these activities is an area of active research. Here, the sole Drosophila melanogaster ortholog, Clic, was targeted for RNAi knockdown to identify genes and biological processes associated with Clic expression. Clic knockdown had a substantial impact on global transcription, altering expression of over 7% of transcribed Drosophila genes. Overrepresentation analysis of differentially expressed genes identified enrichment of Gene Ontology terms including Cytoplasmic Translation, Oxidation-Reduction Process, Heme Binding, Membrane, Cell Junction, and Nucleolus. The top term, Cytoplasmic Translation, was enriched almost exclusively with downregulated genes. Drosophila Clic and vertebrate ortholog Clic4 have previously been tied to ethanol sensitivity and ethanol-regulated expression. Clic knockdown-responsive genes from the present study were found to overlap significantly with gene sets from 4 independently published studies related to ethanol exposure and sensitivity in Drosophila. Bioinformatic analysis of genes shared between these studies revealed an enrichment of genes related to amino acid metabolism, protein processing, oxidation-reduction processes, and lipid particles among others. To determine whether the modulation of ethanol sensitivity by Clic may be related to co-regulated oxidation-reduction processes, we evaluated the effect of hyperoxia on ethanol sedation in Clic knockdown flies. Consistent with previous findings, Clic knockdown reduced acute ethanol sedation sensitivity in flies housed under normoxia. However, this effect was reversed by exposure to hyperoxia, suggesting a common set of molecular-genetic mechanism may modulate each of these processes. This study suggests that Drosophila Clic has a major influence on regulation of oxidative stress signaling and that this function overlaps with the molecular mechanisms of acute ethanol sensitivity in the fly.

Evolution thermique de N-oxydes D'ω-dialkylamino alcanols-1

1984 ◽  
Vol 49 (10) ◽  
pp. 2410-2414 ◽  
Author(s):  
Didier Barbry ◽  
Bruno Hasiak
Keyword(s):  
Hydrogen Atom ◽  
Transition State ◽  
Tertiary Amine ◽  
Amino Alcohol ◽  
Cycloaddition Reaction ◽  
Reduction Process ◽  
The Other ◽  
Dipolar Cycloaddition ◽  
Oxidation Reduction ◽  
Planar Transition

The thermolysis of ω-dimethylamino-1-alkanol N-oxides affords ω-hydroxy-1-alkenes with dimethylhydroxylamine in good yields. The other basic products ( amino alcohol and isoxazolidine) involve oxidation-reduction process between the tertiary amine N-oxide and dimethylhydroxylamine, followed by 1,3-dipolar cycloaddition reaction. Pyrolysis of 5-piperidino-1-pentanol N-oxide proceeds on a path similar to the N-dimethyl compounds. The elimination of an hydrogen atom of the heterocycle does not occur: the preferred planar transition state cannot be attained because of the steric requirements of the ring.

scholarly journals Transcriptome Analysis of Chloride Intracellular Channel Knockdown in Drosophila Identifies Oxidation-Reduction Function as Possible Mechanism of Altered Sensitivity to Ethanol Sedation

2021 ◽  
Author(s):  
Rory M. Weston ◽  
Rebecca E. Schmitt ◽  
Mike Grotewiel ◽  
Michael F. Miles
Keyword(s):  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Reduction Process ◽  
Major Influence ◽  
Biological Processes ◽  
Ethanol Sensitivity ◽  
Substantial Impact ◽  
Reduction Processes ◽  
Oxidation Reduction ◽  
Acute Ethanol

AbstractChloride intracellular channels (CLICs) are a unique family of evolutionarily conserved metamorphic proteins, switching between stable conformations based on redox conditions. CLICs have been implicated in a wide variety biological processes including ion channel activity, apoptosis, membrane trafficking, and enzymatic oxidoreductase activity. Understanding the molecular mechanisms by which CLICs engage in these activities is an area of active research. Here, the sole Drosophila melanogaster ortholog, Clic, was targeted for RNAi knockdown to identify genes and biological processes associated with Clic expression. Clic knockdown had a substantial impact on global transcription, altering expression of over 9% of transcribed Drosophila genes. Overrepresentation analysis of differentially expressed genes identified enrichment of 23 Gene Ontology terms including Cytoplasmic Translation, Oxidation-Reduction Process, Heme Binding, Membrane, Cell Junction, and Nucleolus. The top term, Cytoplasmic Translation, was enriched almost exclusively with downregulated genes. Drosophila Clic and vertebrate ortholog Clic4 have previously been tied to ethanol sensitivity and ethanol-regulated expression. Clic knockdown-responsive genes from the present study were found to overlap significantly with gene sets from 4 independently published studies related to ethanol exposure and sensitivity in Drosophila. Bioinformatic analysis of genes shared between these studies revealed an enrichment of genes related to amino acid metabolism, protein processing, oxidation-reduction processes, and lipid particles among others. To determine whether the modulation of ethanol sensitivity by Clic may be related to co-regulated oxidation-reduction processes, we evaluated the effect of hyperoxia on ethanol sedation in Clic knockdown flies. Consistent with previous findings, Clic knockdown reduced acute ethanol sedation sensitivity in flies housed under nomoxia. However, this effect was reversed by exposure to hyperoxia, suggesting a common set of molecular-genetic mechanism may modulate each of these processes. This study suggests that Drosophila Clic has a major influence on regulation of oxidative stress signaling and that this function overlaps with the molecular mechanisms of acute ethanol sensitivity in the fly.

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