Oxygen

45 pages, 9325 KiB

Open AccessReview

Molecular Mechanisms of Oxygen Evolution Reactions for Artificial Photosynthesis

by Yoshio Nosaka

Oxygen 2023, 3(4), 407-451; https://doi.org/10.3390/oxygen3040027 - 16 Nov 2023

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Addressing the global environmental problem of water splitting to produce hydrogen fuel by solar energy is receiving so much attention. In water splitting, the essential problem to solve is the development of efficient catalysts for oxygen production. In this paper, having the prospect for a practical application of photocatalysts to artificial photosynthesis, molecular mechanisms in the current literature are briefly reviewed. At first, recent progress in the function of the Mn cluster at the natural photosystem II is briefly described. The kinds of devices in which oxygen evolution reaction (OER) catalysts are used were designated: water electrolyzers, photoelectrodes, and photocatalysts. Some methods for analyzing molecular mechanisms in OER catalysis, emphasized by the FTIR method, are shown briefly. After describing common OER mechanisms, the molecular mechanisms are discussed for TiO₂ and BiVO₄ photoelectrodes with our novel data, followed by presenting OER co-catalysts of IrO_2, RuO₂, NiO₂, and other metal oxides. Recent reports describing OER catalysts of perovskites, layered double hydroxides (LDH), metal–organic frameworks (MOF), single-atom catalysts, as well as metal complexes are reviewed. Finally, by comparing with natural photosystem, the required factors to improve the activity of the catalysts for artificial photosynthesis will be discussed. Full article

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13 pages, 969 KiB

Open AccessReview

Mitochondrial Dysfunction and Nanocarrier-Based Treatments in Chronic Obstructive Pulmonary Disease (COPD)

by Kiyoshi Sato and Hiroyoshi Kawakami

Oxygen 2023, 3(4), 394-406; https://doi.org/10.3390/oxygen3040026 - 14 Nov 2023

Cited by 1 | Viewed by 786

Abstract

Mitochondrial dysfunction significantly contributes to the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). To treat mitochondrial dysfunction in COPD, novel drug delivery systems (DDS) are needed. In this review, we provide a brief overview of the current understanding of the factors in COPD and highlight the trends in novel nanocarriers/nanoparticles for targeting mitochondrial dysfunction. These drug-encapsulated nanoparticles are still in the early stages of clinical application but represent the most promising system for COPD therapy. Full article

(This article belongs to the Special Issue Mitochondrial Oxidative Stress in Health and Disease)

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8 pages, 1698 KiB

Open AccessArticle

The Influence of the Atmospheric Electric Field on Soil Redox Potential

by Konstantinos Kourtidis and Michel Vorenhout

Oxygen 2023, 3(4), 386-393; https://doi.org/10.3390/oxygen3040025 - 19 Oct 2023

Viewed by 793

Abstract

Atmospheric electric fields (AEFs) have recently been proposed to link to biogeochemical processes below the Earth’s surface by means of a charge separation. Despite the potential importance of such a process, up to now we almost completely lack the relevant measurements. Here, we extend the database with 2 months of concurrent soil redox and atmospheric electric field measurements. It appears that the changes that occur in the order of days in soil redox are at periods anticorrelated with the logarithm of the positive values of the AEF. However, weather conditions might be driving the anticorrelation rather than a direct link, as the synoptic weather conditions appear to influence soil redox. Soil redox does not respond to changes in the AEF that are of shorter duration, either minutes or several hours, except in some cases of very negative AEFs or very high field strengths in the presence of moderate rainfall. In such a case, the variation in soil redox could be associated with a mechanism that transfers charge to the ground or brings ions towards the ground’s surface. To reach firmer conclusions on the effect of the AEF on soil redox, we need to extend the range of collocated soil redox and AEF measurements so that they cover at least one year. Full article

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12 pages, 2568 KiB

Open AccessArticle

The Kelch/Nrf2 Antioxidant System as a Target for Some Marine Fungal Metabolites

by Ekaterina A. Yurchenko, Olga O. Khmel, Liliana E. Nesterenko and Dmitry L. Aminin

Oxygen 2023, 3(4), 374-385; https://doi.org/10.3390/oxygen3040024 - 28 Sep 2023

Viewed by 878

Abstract

Marine fungal metabolites often exhibit antioxidant activity, but their effects on the Keap1/Nrf2 cellular system are rarely studied, possibly due to insufficient isolated amounts. In this work, we used a bioinformatics approach to evaluate the ability of some promising cytoprotective compounds to bind Kelch domain of Keap1 protein, and thus inhibit its interaction with Nrf2. The molecular docking data suggested that gliorosein, niveoglaucin A, 6-hydroxy-N-acetyl-β-oxotryptamine, 4-hydroxyscytalone and 4-hydroxy-6-dehydroxyscytalone can form the hydrogen building with Arg415 or Arg483 amino acid residues of P1-P2 sub-pockets in the Nrf2 binding site of Keap1′s Kelch domain. These positions of the small molecules in the Kelch domain of Keap1 can inhibit the interaction of Keap1 with Nrf2 and enhance the nuclear translocation of Nrf2 from cytosol that can result in overexpression of relative genes. This assumption, based on virtual screening of a number of low molecular weight metabolites of marine fungi, makes them promising for further studies. Full article

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Oxygen, Volume 3, Issue 4 (December 2023) – 4 articles

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