scholarly journals Photo-Electrochemical Oxygen Evolution Reaction by Biomimetic CaMn2O4 Catalyst

2019 ◽  
Vol 9 (11) ◽  
pp. 2196
Author(s):  
Ankita Gagrani ◽  
Mohammed Alsultan ◽  
Gerhard F. Swiegers ◽  
Takuya Tsuzuki
Keyword(s):  
Control Sample ◽  
Structural Similarity ◽  
Oxygen Evolving Complex ◽  
New Class ◽  
Irregular Shapes ◽  
The Earth ◽  
Earth Abundant ◽  
The Difference ◽  
Oxygen Evolving ◽  
Electrochemical Oxygen

Calcium manganese oxide catalysts are a new class of redox catalysts with significant importance because of their structural similarity to natural oxygen-evolving complex in plant cells and the earth-abundant elemental constituents. In the present study, the photo-electrocatalytic properties of CaMn2O4 in water-splitting were investigated. CaMn2O4 powders with irregular shapes and nanowire shapes were synthesised using mechanochemical processing and a hydrothermal method, respectively. The anode in a photo-electrochemical cell was fabricated by embedding CaMn2O4 powders within polypyrrole. The results showed that CaMn2O4 induced a higher dark and light current in comparison to the control sample (polypyrrole alone). CaMn2O4 nanowires exhibited higher dark and light current in comparison to irregular-shaped CaMn2O4 powders. The difference was attributable to the higher surface area of nanowires compared to the irregular-shaped particles, rather than the difference in exposed crystal facets.

scholarly journals Characterization of the Free and Membrane-Associated Fractions of the Thylakoid Lumen Proteome in Arabidopsis thaliana

2021 ◽  
Vol 22 (15) ◽  
pp. 8126
Author(s):  
Peter J. Gollan ◽  
Andrea Trotta ◽  
Azfar A. Bajwa ◽  
Ilaria Mancini ◽  
Eva-Mari Aro
Keyword(s):  
Arabidopsis Thaliana ◽  
Photosynthetic Electron Transport ◽  
Oxygen Evolving Complex ◽  
Ps Ii ◽  
Post Translational Modifications ◽  
Thylakoid Lumen ◽  
Novel Proteins ◽  
The Difference ◽  
Oxygen Evolving

The thylakoid lumen houses proteins that are vital for photosynthetic electron transport, including water-splitting at photosystem (PS) II and shuttling of electrons from cytochrome b6f to PSI. Other lumen proteins maintain photosynthetic activity through biogenesis and turnover of PSII complexes. Although all lumen proteins are soluble, these known details have highlighted interactions of some lumen proteins with thylakoid membranes or thylakoid-intrinsic proteins. Meanwhile, the functional details of most lumen proteins, as well as their distribution between the soluble and membrane-associated lumen fractions, remain unknown. The current study isolated the soluble free lumen (FL) and membrane-associated lumen (MAL) fractions from Arabidopsis thaliana, and used gel- and mass spectrometry-based proteomics methods to analyze the contents of each proteome. These results identified 60 lumenal proteins, and clearly distinguished the difference between the FL and MAL proteomes. The most abundant proteins in the FL fraction were involved in PSII assembly and repair, while the MAL proteome was enriched in proteins that support the oxygen-evolving complex (OEC). Novel proteins, including a new PsbP domain-containing isoform, as well as several novel post-translational modifications and N-termini, are reported, and bi-dimensional separation of the lumen proteome identified several protein oligomers in the thylakoid lumen.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

Anti-adhesion Molecules in IBD: Does Gut Selectivity Really Make the Difference?

2019 ◽  
Vol 25 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Ferdinando D'Amico ◽  
Giulia Roda ◽  
Laurent Peyrin-Biroulet ◽  
Silvio Danese
Keyword(s):  
Adhesion Molecules ◽  
Biological Treatment ◽  
Current Data ◽  
New Drugs ◽  
Inflammatory Infiltration ◽  
New Class ◽  
Bowel Diseases ◽  
Inflammatory Bowel ◽  
The Difference ◽  
Necrosis Factor

Inflammatory Bowel Disease is lifetime chronic progressive inflammatory disease. A considerable portion of patients, do not respond or lose response or experience side effect to “traditional” biological treatment such as anti-tumor necrosis factor (TNF)-α agents. The concept that the blockade of T cell traffic to the gut controls inflammation has stimulated the development of new drugs which selectively targets molecules involved in controlling cell homing to the intestine. The result is the reduction of the chronic inflammatory infiltration in the gut. In this regard, anti-adhesion molecules represent a new class of drugs for patients who don’t respond or lose response to traditional therapy. Moreover, some of these molecules such as vedolizumab, offer the advantage to target the delivery of a drug to the gut (gut selectivity) which could increase clinical efficacy and limit potential adverse events. In this article, we will give an overview of the current data on anti-adhesion molecules in Inflammatory Bowel Diseases.

scholarly journals Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 371
Author(s):  
Koua
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Long Range ◽  
Electron Acceptor ◽  
Structural Changes ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Long Range Interactions ◽  
Structural Perturbations ◽  
Oxygen Evolving

The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.

scholarly journals CaMn3IVO4 Cubane Models of the Oxygen Evolving Complex: Spin Ground States S < 9/2 and the Effect of Oxo Protonation

2021 ◽  
Author(s):  
Heui Beom Lee ◽  
Angela A Shiau ◽  
David Marchiori ◽  
Paul H Oyala ◽  
BYUNG-KUK Yoo ◽  
...  
Keyword(s):  
Ground States ◽  
Oxygen Evolving Complex ◽  
Complex Spin ◽  
Oxygen Evolving
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