scholarly journals Materials and possible mechanisms of extremely large magnetoresistance: A review

2021 ◽  
Author(s):  
Rui Niu ◽  
Wenka Zhu
Keyword(s):  
External Field ◽  
High Mobility ◽  
Magnetic Scattering ◽  
Electron Hole ◽  
Functional Feature ◽  
Spin Configuration ◽  
Residual Resistance ◽  
Leading Role ◽  
Wide Range ◽  
Solid Foundation

Abstract Magnetoresistance (MR) is a characteristic that the resistance of a substance changes with the external magnetic field, reflecting various physical origins and microstructures of the substance. A large MR, namely a huge response to a low external field, has always been a useful functional feature in industrial technology and a core goal pursued by physicists and materials scientists. Conventional large MR materials are mainly manganites, whose colossal MR (CMR) can be as high as -90%. The dominant mechanism is attributed to spin configuration aligned by the external field, which reduces magnetic scattering and thus resistance. In recent years, some new systems have shown an extremely large unsaturated MR (XMR). Unlike ordinary metals, the positive MR of these systems can reach 103-108% and is persistent under super high magnetic fields. The XMR materials are mainly metals or semimetals, distributed in high-mobility topological or non-topological systems, and some are magnetic, which suggests a wide range of application scenarios. Various mechanisms have been proposed for the potential physical origin of XMR, including electron-hole compensation, steep band, ultrahigh mobility, high residual resistance ratio, topological fermions, etc. It turns out that some mechanisms play a leading role in certain systems, while more are far from clearly defined. In addition, the researches on XMR are largely overlapped or closely correlated with other recently rising physics and materials researches, such as topological matters and two-dimensional (2D) materials, which makes elucidating the mechanism of XMR even more important. Moreover, the disclosed novel properties will lay a broad and solid foundation for the design and development of functional devices. In this review, we will discuss several aspects in the following order: (I) Introduction, (II) XMR materials and classification, (III) Proposed mechanisms for XMR, (IV) Correlation with other systems (featured), and (V) Conclusions and outlook.

scholarly journals The PI3K/Akt Pathway: Emerging Roles in Skin Homeostasis and a Group of Non-Malignant Skin Disorders

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1219
Author(s):  
Yan Teng ◽  
Yibin Fan ◽  
Jingwen Ma ◽  
Wei Lu ◽  
Na Liu ◽  
...  
Keyword(s):  
Cell Carcinoma ◽  
Akt Pathway ◽  
Skin Disorders ◽  
Phosphatidylinositol 3 Kinase ◽  
Skin Development ◽  
Wide Range ◽  
Malignant Skin ◽  
Solid Foundation ◽  
And Migration ◽  
Poor Outcomes

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway regulates cell proliferation, differentiation, and migration, along with angiogenesis and metabolism. Additionally, it could mediate skin development and homeostasis. There is much evidence to suggest that dysregulation of PI3K/Akt pathway is frequently associated with several human cutaneous malignancies like malignant melanoma (MM), basal cell carcinoma (BCC), and cutaneous squamous cell carcinoma (SCC), as well as their poor outcomes. Nevertheless, emerging roles of PI3K/Akt pathway cascade in a group of common non-malignant skin disorders including acne and psoriasis, among others, have been recognized. The enhanced understanding of dysfunction of PI3K/Akt pathway in patients with these non-malignant disorders has offered a solid foundation for the progress of updated therapeutic targets. This article reviews the latest advances in the roles of PI3K/Akt pathway and their targets in the skin homeostasis and progression of a wide range of non-malignant skin disorders and describes the current progress in preclinical and clinical researches on the involvement of PI3K/Akt pathway targeted therapies.

scholarly journals Properties of the Biexciton and the Electron-Hole-Plasma in Highly Excited GaN

1997 ◽  
Vol 2 ◽  
Author(s):  
J.-Chr. Holst ◽  
L. Eckey ◽  
A. Hoffmann ◽  
I. Broser ◽  
H. Amano ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Blue Laser ◽  
Basic Material ◽  
Organic Chemical ◽  
Electron Hole ◽  
Hole Plasma ◽  
Electron Hole Plasma ◽  
Wide Range ◽  
Gain Spectra ◽  
Excitation Processes

High-excitation processes like biexciton decay and recombination of an electron-hole-plasma are discussed as efficient mechanisms for lasing in blue laser diodes [1]. Therefore, the investigation of these processes is of fundamental importance to the understanding of the properties of GaN as a basic material for optoelectronical applications. We report on comprehensive photoluminescence and gain measurements of highly excited GaN epilayers grown by metal-organic chemical vapor deposition (MOCVD) over a wide range of excitation densities and temperatures. For low temperatures the decay of biexcitons and the electron-hole-plasma dominate the spontaneous-emission and gain spectra. A spectral analysis of the lineshape of these emissions is performed and the properties of the biexciton and the electron-hole-plasma in GaN will be disscused in comparison to other wide-gap materials. At increased temperatures up to 300 K exciton-exciton-scattering and band-to-band recombination are the most efficient processes in the gain spectra beside the electron-hole-plasma.

scholarly journals HMBG1 as a Driver of Inflammatory and Immune Processes in the Pathogenesis of Ocular Diseases

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Yi Liu ◽  
Guo-Bin Zhuang ◽  
Xue-Zhi Zhou
Keyword(s):  
Current Knowledge ◽  
High Mobility ◽  
Retinal Cell ◽  
Ocular Diseases ◽  
Wide Range ◽  
Glycation End Products ◽  
Cell Layers ◽  
Proinflammatory Activity ◽  
And Migration ◽  
Proliferation And Migration

High-mobility group box 1 (HMGB1) is a nuclear protein that can also act as an extracellular trigger of inflammation, proliferation, and migration in eye diseases. It induces signaling pathways by binding to the receptor for advanced glycation end products (RAGE) and Toll-like receptors (TLRs) 2, 4, and 9. This proinflammatory activity is considered to be important in the pathogenesis of a wide range of ocular diseases resulting from hemodynamic changes, presence of neovascular endothelial cells, secretion of intraocular immune factors or inflammation, and apoptosis of retinal cell layers. Further work is needed to elucidate in detail how HMGB1 contributes to ocular disease and how its damaging activity can be modulated. In this review, we summarize current knowledge on HMGB1 as a ligand that can evoke inflammation and immune responses in ocular diseases.

scholarly journals Dynamic Routing and Coordination of Cluster for Unmanned Aerial Vehicle (UAV) Swarms

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ali Abbas ◽  
Bhawani Shankar Chowdhry ◽  
Muhammad Saqib ◽  
Vishal Dattana
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Efficient Solution ◽  
High Mobility ◽  
Combinatorial Problem ◽  
Communication Graph ◽  
Frequent Change ◽  
Swarm Optimization ◽  
Wide Range ◽  
Aerial Vehicle ◽  
Simulation Results

The flying networks provide an efficient solution for a wide range of military and commercial purposes. The demand for portable and flexible communication is directed towards a quick growth in interaction among unmanned aerial vehicles (UAVs). Due to the frequent change in topology and high mobility of vehicles, routing and coordination becomes a challenging task. To maximize the throughput of the network, this study addresses the UAV swarm’s problems related to the coordination and routing and defines the proposed solution to solve these issues. For this, a network is assumed which contains an equal number of dynamic vehicles. It also presents the communication graph concept of UAVs and designs a fixed-wing UAV model to improve the efficiency of the network in terms of throughput. Furthermore, the proposed algorithm based on Cauchy particle swarm optimization (CPSO) aims towards the better performance of UAV swarms and aims to solve the combinatorial problem. The simulation results show and confirm the performance of the proposed algorithm.

scholarly journals Prediction of the structural and electronic properties of MoxTi1−xS2 monolayers via first principle simulations

2020 ◽  
Vol 10 ◽  
pp. 184798042095509
Author(s):  
Ankit Kumar Verma ◽  
Federico Raffone ◽  
Giancarlo Cicero
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Transition Metal Dichalcogenides ◽  
Stable Phase ◽  
Two Dimensional ◽  
Electron Hole ◽  
Effective Electron ◽  
Wide Range ◽  
Structural And Electronic Properties ◽  
Metal Dichalcogenides

Two-dimensional transition metal dichalcogenides have gained great attention because of their peculiar physical properties that make them interesting for a wide range of applications. Lately, alloying between different transition metal dichalcogenides has been proposed as an approach to control two-dimensional phase stability and to obtain compounds with tailored characteristics. In this theoretical study, we predict the phase diagram and the electronic properties of Mo xTi1− xS2 at varying stoichiometry and show how the material is metallic, when titanium is the predominant species, while it behaves as a p-doped semiconductor, when approaching pure MoS2 composition. Correspondingly, the thermodynamically most stable phase switches from the tetragonal to the hexagonal one. Further, we present an example which shows how the proposed alloys can be used to obtain new vertical two-dimensional heterostructures achieving effective electron/hole separation.

scholarly journals The dark exciton ground state promotes photon-pair emission in individual perovskite nanocrystals

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Philippe Tamarat ◽  
Lei Hou ◽  
Jean-Baptiste Trebbia ◽  
Abhishek Swarnkar ◽  
Louis Biadala ◽  
...  
Keyword(s):  
Near Infrared ◽  
Exciton State ◽  
Lead Iodide ◽  
Electron Hole ◽  
Light Emitting ◽  
Perovskite Nanocrystals ◽  
Light Emitting Devices ◽  
Optical And Electronic Properties ◽  
Wide Range ◽  
Halide Perovskites

AbstractCesium lead halide perovskites exhibit outstanding optical and electronic properties for a wide range of applications in optoelectronics and for light-emitting devices. Yet, the physics of the band-edge exciton, whose recombination is at the origin of the photoluminescence, is not elucidated. Here, we unveil the exciton fine structure of individual cesium lead iodide perovskite nanocrystals and demonstrate that it is governed by the electron-hole exchange interaction and nanocrystal shape anisotropy. The lowest-energy exciton state is a long-lived dark singlet state, which promotes the creation of biexcitons at low temperatures and thus correlated photon pairs. These bright quantum emitters in the near-infrared have a photon statistics that can readily be tuned from bunching to antibunching, using magnetic or thermal coupling between dark and bright exciton sublevels.

scholarly journals Radioprotective Role of Peroxiredoxin 6

Antioxidants ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 15 ◽  
Author(s):  
Mars G. Sharapov ◽  
Vladimir I. Novoselov ◽  
Sergey V. Gudkov
Keyword(s):  
Ionizing Radiation ◽  
Mammalian Cells ◽  
Redox Homeostasis ◽  
Phospholipid Metabolism ◽  
Pathological Effect ◽  
Peroxiredoxin 6 ◽  
Leading Role ◽  
Wide Range ◽  
Radiosensitive Organs ◽  
Peroxidase Enzymes

Peroxiredoxin 6 (Prdx6) is a member of an evolutionary ancient family of peroxidase enzymes with diverse functions in the cell. Prdx6 is an important enzymatic antioxidant. It reduces a wide range of peroxide substrates in the cell, thus playing a leading role in the maintenance of the redox homeostasis in mammalian cells. Beside peroxidase activity, Prdx6 has been shown to possess an activity of phospholipase A2, an enzyme playing an important role in membrane phospholipid metabolism. Moreover, Prdx6 takes part in intercellular and intracellular signal transduction due to its peroxidase and phospholipase activity, thus facilitating the initiation of regenerative processes in the cell, suppression of apoptosis, and activation of cell proliferation. Being an effective and important antioxidant enzyme, Prdx6 plays an essential role in neutralizing oxidative stress caused by various factors, including action of ionizing radiation. Endogenous Prdx6 has been shown to possess a significant radioprotective potential in cellular and animal models. Moreover, intravenous infusion of recombinant Prdx6 to animals before irradiation at lethal or sublethal doses has shown its high radioprotective effect. Exogenous Prdx6 effectively alleviates the severeness of radiation lesions, providing normalization of the functional state of radiosensitive organs and tissues, and leads to a significant elevation of the survival rate of animals. Prdx6 can be considered as a potent and promising radioprotective agent for reducing the pathological effect of ionizing radiation on mammalian organisms. The radioprotective properties and mechanisms of radioprotective action of Prdx6 are discussed in the current review.

Bioerosion: Eating Rocks for Fun and Profit

1992 ◽  
Vol 5 ◽  
pp. 121-129 ◽  
Author(s):  
Richard G. Bromley
Keyword(s):  
Trace Fossils ◽  
European Continent ◽  
Philip Ii ◽  
Leading Role ◽  
Short Course ◽  
Wide Range ◽  
Philip Ii Of Spain ◽  
Wood Boring ◽  
Hard Substrates

“Bioerosion” was coined by Neumann (1966) as an abbreviation of “biologic erosion”, and describes every form of biologic penetration into hard substrates, i.e., lithic (including skeletal) and woody. An extremely wide range of organisms causes bioerosion (see Bromley, 1970; Warme, 1970, 1975; Ekdale et al., 1984, p. 108–139). The work of these organisms produces trace fossils at all scales, from microscopic to gigantic. Minute scars etched by brachiopod pedicles have a paleoecologic story to tell; at another scale, cliff sapping by communities of boring bivalves and rasping limpets can cause major geographic changes. For example, the work of pholad bivalves played a leading role in the separation of England from the European continent; and had the great armada, sent against England by Philip II of Spain in 1588, not been annihilated by wood-boring shipworms (bivalves), the language of this short-course would have been Spanish.

Brian Eyre CBE FREng. 29 November 1933 — 28 July 2014

2016 ◽  
Vol 62 ◽  
pp. 147-166
Author(s):  
Derek Pooley ◽  
George Smith ◽  
Colin Windsor
Keyword(s):  
Nuclear Power ◽  
Chief Executive ◽  
Structural Components ◽  
Theoretical Understanding ◽  
Leading Role ◽  
Void Swelling ◽  
Intergranular Embrittlement ◽  
Wide Range ◽  
East End ◽  
The Uk

Brian Eyre was an outstanding metallurgist who played a leading role in the development of nuclear engineering materials. His experiments on irradiated metals enabled a theoretical understanding of the mechanisms of radiation damage, and in particular the formation of voids and void swelling in structural steels. His work on the fracture of metals advanced our understanding of intergranular embrittlement and helped define the specifications of the structural components in nuclear reactors. He rose from a humble upbringing in London's East End to become Chief Executive of the UK Atomic Energy Authority (UKAEA). He was instrumental in transforming the UKAEA from a organization whose mission was to develop nuclear power generating systems into the privatized AEA Technology, which worked on a wide range of technologies on a customer–contractor basis.

scholarly journals NO2 and NH3 Sensing Characteristics of Inkjet Printing Graphene Gas Sensors

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3379 ◽  
Author(s):  
Caterina Travan ◽  
Alexander Bergmann
Keyword(s):  
Gas Sensors ◽  
Inkjet Printing ◽  
High Mobility ◽  
High Sensitivity ◽  
Low Noise ◽  
Manufacturing Method ◽  
Long Term Stability ◽  
Wide Range ◽  
Ideal Technique

Graphene is a good candidate for filling the market requirements for cheap, high sensitivity, robust towards contamination, low noise, and low power consumption gas sensors, thanks to its unique properties, i.e., large surface, high mobility, and long-term stability. Inkjet printing is a cheap additive manufacturing method allowing fast, relatively precise and contactless deposition of a wide range of materials; it can be considered therefore the ideal technique for fast deposition of graphene films on thin substrates. In this paper, the sensitivity of graphene-based chemiresistor gas sensors, fabricated through inkjet printing, is investigated using different concentrations of graphene in the inks. Samples have been produced and characterized in terms of response towards humidity, nitrogen dioxide, and ammonia. The presented results highlight the importance of tuning the layer thickness and achieving good film homogeneity in order to maximize the sensitivity of the sensor.

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