scholarly journals Research journey of respirasome

2020 ◽  
Vol 11 (5) ◽  
pp. 318-338 ◽  
Author(s):  
Meng Wu ◽  
Jinke Gu ◽  
Shuai Zong ◽  
Runyu Guo ◽  
Tianya Liu ◽  
...  
Keyword(s):  
Short Review ◽  
Research Field ◽  
Atomic Scale ◽  
Inner Mitochondrial Membrane ◽  
Macroscopic Scale ◽  
The Past ◽  
Transport Chain ◽  
High Resolution Structure ◽  
New Perspective ◽  
Resolution Structure

AbstractRespirasome, as a vital part of the oxidative phosphorylation system, undertakes the task of transferring electrons from the electron donors to oxygen and produces a proton concentration gradient across the inner mitochondrial membrane through the coupled translocation of protons. Copious research has been carried out on this lynchpin of respiration. From the discovery of individual respiratory complexes to the report of the high-resolution structure of mammalian respiratory supercomplex I1III2IV1, scientists have gradually uncovered the mysterious veil of the electron transport chain (ETC). With the discovery of the mammalian respiratory mega complex I2III2IV2, a new perspective emerges in the research field of the ETC. Behind these advances glitters the light of the revolution in both theory and technology. Here, we give a short review about how scientists ‘see’ the structure and the mechanism of respirasome from the macroscopic scale to the atomic scale during the past decades.

scholarly journals Active Sites in Heterogeneous Catalytic Reaction on Metal and Metal Oxide: Theory and Practice

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 478 ◽  
Author(s):  
Yanbo Pan ◽  
Xiaochen Shen ◽  
Libo Yao ◽  
Abdulaziz Bentalib ◽  
Zhenmeng Peng
Keyword(s):  
Metal Oxide ◽  
Active Sites ◽  
Research Direction ◽  
Short Review ◽  
Research Field ◽  
Theory And Practice ◽  
Future Research ◽  
Heterogeneous Catalytic ◽  
The Past ◽  
Catalysis Process

Active sites play an essential role in heterogeneous catalysis and largely determine the reaction properties. Yet identification and study of the active sites remain challenging owing to their dynamic behaviors during catalysis process and issues with current characterization techniques. This article provides a short review of research progresses in active sites of metal and metal oxide catalysts, which covers the past achievements, current research status, and perspectives in this research field. In particular, the concepts and theories of active sites are introduced. Major experimental and computational approaches that are used in active site study are summarized, with their applications and limitations being discussed. An outlook of future research direction in both experimental and computational catalysis research is provided.

scholarly journals Dimeric and high-resolution structures of Chlamydomonas Photosystem I from a temperature-sensitive Photosystem II mutant

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ido Caspy ◽  
Tom Schwartz ◽  
Vinzenz Bayro-Kaiser ◽  
Mariia Fadeeva ◽  
Amit Kessel ◽  
...  
Keyword(s):  
High Resolution ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Water Molecules ◽  
Temperature Sensitive ◽  
Asymmetric Distribution ◽  
Light Harvesting Complexes ◽  
Transport Chain ◽  
High Resolution Structure ◽  
Resolution Structure

AbstractWater molecules play a pivotal functional role in photosynthesis, primarily as the substrate for Photosystem II (PSII). However, their importance and contribution to Photosystem I (PSI) activity remains obscure. Using a high-resolution cryogenic electron microscopy (cryo-EM) PSI structure from a Chlamydomonas reinhardtii temperature-sensitive photoautotrophic PSII mutant (TSP4), a conserved network of water molecules - dating back to cyanobacteria - was uncovered, mainly in the vicinity of the electron transport chain (ETC). The high-resolution structure illustrated that the water molecules served as a ligand in every chlorophyll that was missing a fifth magnesium coordination in the PSI core and in the light-harvesting complexes (LHC). The asymmetric distribution of the water molecules near the ETC branches modulated their electrostatic landscape, distinctly in the space between the quinones and FX. The data also disclosed the first observation of eukaryotic PSI oligomerisation through a low-resolution PSI dimer that was comprised of PSI-10LHC and PSI-8LHC.

High-resolution structure determination by ALCHEMI

1983 ◽  
Vol 41 ◽  
pp. 178-181 ◽  
Author(s):  
Peter G. Self ◽  
Peter R. Buseck
Keyword(s):  
Site Occupancy ◽  
Real Space ◽  
Unit Cell ◽  
Bragg Angle ◽  
Electron Current ◽  
High Resolution Structure ◽  
Beam Incident ◽  
Crystallographic Planes ◽  
Electron Beam Incident ◽  
Resolution Structure

ALCHEMI (Atom Location by CHanneling Enhanced Microanalysis) enables the site occupancy of atoms in single crystals to be determined. In this article the fundamentals of the method for both EDS and EELS will be discussed. Unlike HRTEM, ALCHEMI does not place stringent resolution requirements on the microscope and, because EDS clearly distinguishes between elements of similar atomic number, it can offer some advantages over HRTEM. It does however, place certain constraints on the crystal. These constraints are: a) the sites of interest must lie on alternate crystallographic planes, b) the projected charge density on the alternate planes must be significantly different, and c) there must be at least one atomic species that lies solely on one of the planes.An electron beam incident on a crystal undergoes elastic scattering; in reciprocal space this is seen as a diffraction pattern and in real space this is a modulation of the electron current across the unit cell. When diffraction is strong (i.e., when the crystal is oriented near to the Bragg angle of a low-order reflection) the electron current at one point in the unit cell will differ significantly from that at another point.

Cathodoluminescence of Catalyst Crystallites

1982 ◽  
Vol 40 ◽  
pp. 664-665
Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick
Keyword(s):  
Defect Density ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Semiconductor Materials ◽  
Environmental Cell ◽  
High Resolution Structure ◽  
Commercially Important ◽  
Crystallographic Defects ◽  
Resolution Structure

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.

Metal and Non-Metal Catalysts in the Synthesis of Five-Membered S-Heterocycles

2019 ◽  
Vol 16 (2) ◽  
pp. 258-275 ◽  
Author(s):  
Navjeet Kaur
Keyword(s):  
Organic Synthesis ◽  
Biological Activities ◽  
Reaction Times ◽  
Research Field ◽  
Environmentally Benign ◽  
Metal Catalyst ◽  
Efficient Synthesis ◽  
Heterocyclic Molecules ◽  
The Past ◽  
Harsh Conditions

Background:A wide variety of biological activities are exhibited by N, O and S containing heterocycles and recently, many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and non-metal catalyst has become a highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of S-heterocylces in the presence of metal and non-metal catalyst. The synthesis of five-membered S-heterocycles is described here.Objective:There is a need for the development of rapid, efficient and versatile strategy for the synthesis of heterocyclic rings. Metal, non-metal and organocatalysis involving methods have gained prominence because traditional conditions have disadvantages such as long reaction times, harsh conditions and limited substrate scope.Conclusion:The metal-, non-metal-, and organocatalyst assisted organic synthesis is a highly dynamic research field. For ßthe chemoselective and efficient synthesis of heterocyclic molecules, this protocol has emerged as a powerful route. Various methodologies in the past few years have been pointed out to pursue more sustainable, efficient and environmentally benign procedures and products. Among these processes, the development of new protocols (catalysis), which avoided the use of toxic reagents, are the focus of intense research.

“The Past, Present, and Future of Accounting History”: A Comment on the State of Accounting History

2020 ◽  
Vol 47 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Garry D. Carnegie
Keyword(s):  
English Language ◽  
Research Field ◽  
The State ◽  
International Accounting ◽  
Scholarly Research ◽  
Recent Contribution ◽  
Global Society ◽  
Accounting History ◽  
The Past

ABSTRACT This response to the recent contribution by Matthews (2019) entitled “The Past, Present, and Future of Accounting History” specifically deals with the issues associated with concentrating on counting publication numbers in examining the state of a scholarly research field at the start of the 2020s. It outlines several pitfalls with the narrowly focused publications count analysis, in selected English language journals only, as provided by Matthews. The commentary is based on three key arguments: (1) accounting history research and publication is far more than a “numbers game”; (2) trends in the quality of the research undertaken and published are paramount; and (3) international publication and accumulated knowledge in accounting history are indeed more than a collection of English language publications. The author seeks to contribute to discussion and debate between accounting historians and other researchers for the benefit and development of the international accounting history community and global society.

scholarly journals A Bibliometric Analysis of Human-Machine Interaction Methodology for Electric-Powered Wheelchairs Driving from 1998 to 2020

2021 ◽  
Vol 18 (14) ◽  
pp. 7567
Author(s):  
Xiaochen Zhang ◽  
Lanxin Hui ◽  
Linchao Wei ◽  
Fuchuan Song ◽  
Fei Hu
Keyword(s):  
The Elderly ◽  
Research Field ◽  
Future Research ◽  
Human Machine Interaction ◽  
Research Directions ◽  
The Past ◽  
Power Wheelchairs ◽  
The Disabled ◽  
Future Research Directions ◽  
Machine Interaction

Electric power wheelchairs (EPWs) enhance the mobility capability of the elderly and the disabled, while the human-machine interaction (HMI) determines how well the human intention will be precisely delivered and how human-machine system cooperation will be efficiently conducted. A bibliometric quantitative analysis of 1154 publications related to this research field, published between 1998 and 2020, was conducted. We identified the development status, contributors, hot topics, and potential future research directions of this field. We believe that the combination of intelligence and humanization of an EPW HMI system based on human-machine collaboration is an emerging trend in EPW HMI methodology research. Particular attention should be paid to evaluating the applicability and benefits of the EPW HMI methodology for the users, as well as how much it contributes to society. This study offers researchers a comprehensive understanding of EPW HMI studies in the past 22 years and latest trends from the evolutionary footprints and forward-thinking insights regarding future research.

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