Spin Transfer Torque in Antiferromagnetic Spin-Valves: From Clean to Disordered Regimes

Current-driven spin torques in metallic spin-valves composed of antiferromagnets are theoretically studied using the non-equilibrium Green's function method implemented on a tight-binding model. We focus our attention on G-type and L-type antiferromagnets in both clean and disordered regimes. In such structures, spin torques can either rotate the magnetic order parameter coherently (coherent torque) or compete with the internal antiferromagnetic exchange (exchange torque). We show that, depending on the symmetry of the spin-valve, the coherent and exchange torques can be either in the plane, {\alpha} n\times(q \times n) or out of the plane {\alpha} n \times q, where q and n are the directions of the order parameter of the polarizer and the free antiferromagnetic layers, respectively. Although disorder conserves the symmetry of the torques, it strongly reduces the torque magnitude, pointing out the need for momentum conservation to ensure strong spin torque in antiferromagnetic spin-valvesComment: 10 pages, 11 figure

MHD heat transfer in W-shaped inclined cavity containing a porous medium saturated with Ag/Al2O3 hybrid nanofluid in the presence of uniform heat generation/absorption

© 2020 by the Authors. In this paper, a 2D numerical study of natural convection heat transfer in a W-shaped inclined enclosure with a variable aspect ratio was performed. The enclosure contained a porous medium saturated with Ag/Al2O3 hybrid nanofluid in the presence of uniform heat generation or absorption under the effect of a uniform magnetic field. The vertical walls of the enclosure were heated differentially; however, the top and bottom walls were kept insulated. The governing equations were solved with numerical simulation software COMSOL Multiphysics which is based on the finite element method. The results showed that the convection heat transfer was improved with the increase of the aspect ratio; the average Nusselt number reached a maximum for an aspect ratio (AR) = 0.7 and the effect of the inclination was practically negligible for an aspect ratio of AR = 0.7. The maximum heat transfer performance was obtained for an inclination of ω = 15 and the minimum is obtained for ω = 30. The addition of composite nanoparticles ameliorated the convection heat transfer performance. This effect was proportional to the increase of Rayleigh and Darcy numbers, the aspect ratio and the fraction of Ag in the volumetric fraction of nanoparticles

Hypoxia inducible factor-1α accumulation in steatotic liver preservation: Role of nitric oxide

Open-Acces journal.-- et al.[Aim]: To examine the relevance of hypoxia inducible factor (HIF-1) and nitric oxide (NO) on the preservation of fatty liver against cold ischemia-reperfusion injury (IRI). Methods]: We used an isolated perfused rat liver model and we evaluated HIF-1α in steatotic and non-steatotic livers preserved for 24 h at 4°C in University of Wisconsin and IGL-1 solutions, and then subjected to 2 h of normothermic reperfusion. After normoxic reperfusion, liver enzymes, bile production, bromosulfophthalein clearance, as well as HIF-1α and NO [endothelial NO synthase (eNOS) activity and nitrites/nitrates] were also measured. Other factors associated with the higher susceptibility of steatotic livers to IRI, such as mitochondrial damage and vascular resistance were evaluated. [Results]: A significant increase in HIF-1α was found in steatotic and non-steatotic livers preserved in IGL-1 after cold storage. Livers preserved in IGL-1 showed a significant attenuation of liver injury and improvement in liver function parameters. These benefits were enhanced by the addition of trimetazidine (an antiischemic drug), which induces NO and eNOS activation, to IGL-1 solution. In normoxic reperfusion, the presence of NO favors HIF-1α accumulation, promoting also the activation of other cytoprotective genes, such as hemeoxygenase- 1. [Concluison]: We found evidence for the role of the HIF-1α/NO system in fatty liver preservation, especially when IGL-1 solution is used. © 2010 Baishideng.Supported by The Ministerio de de Sanidad y Consumo (PI 081988), CIBER-EHD, Instituto Carlos III, Madrid and Ministerio de Asuntos Exteriores y de Cooperación Internacionales (A/020255/08 and A/02987/09), MadridPeer Reviewe

Sex-specific Outcomes of Acute Stroke in Patients with Systemic Lupus Erythematosus : A National Inpatient Sample Study

We would like to acknowledge the HCUP Data Partners (https://www.hcup-us.ahrq.gov/db/hcupdatapartners.jsp, accessed on 28 December 2022).Peer reviewedPublisher PD

A Systematic Design of a Compact Wideband Hybrid Directional Coupler Based on Printed RGW Technology

Printed ridge gap waveguide (PRGW) is considered among the state of art guiding technologies due to its low signal distortion and low loss at Millimeter Wave (mmWave) spectrum, which motivates the research community to use this guiding structure as a host technology for various passive microwave and mmWave components. One of the most important passive components used in antenna beam-switching networks is the quadrature hybrid directional coupler providing signal power division with 90° phase shift. A featured design of a broadband and compact PRGW hybrid coupler is propose in this paper. A novel design methodology, based on mode analysis, is introduced to design the objective coupler. The proposed design is suitable for mmWave applications with small electrical dimensions ( 1.2λo×1.2λo ), low loss, and wide bandwidth. The proposed hybrid coupler is fabricated on Roger/RT 6002 substrate material of thickness 0.762 mm. The measured results highlight that the coupler can provide a good return loss with a bandwidth of 26.5% at 30 GHz and isolation beyond 15 dB. The measured phase difference between the coupler output ports is equal 90∘± 5∘ through the interested operating bandwidth. A clear agreement between the simulated and the measured results over the assigned operating bandwidth has been illustrated

Characterisation of the potentially diverse transcriptional regulatory mechanisms of human coagulation PZ gene.

Protein Z (PZ) is a vitamin k-dependent plasma glycoprotein produced mainly in the liver, which circulates as a complex with PZ-dependent protease inhibitor. Human PZ has been reported as having both procoagulant and anticoagulant activity, but its anticoagulant role appears to be more physiologically relevant. PZ levels vary widely among healthy individuals (normal range of 0.6 to 5.7 mug/mL) with the average being higher in men than women. The aim of this study was to investigate the mechanisms by which PZ expression is controlled at the level of transcription, including whether hormonal and/or inflammatory signals modify expression and, therefore, possibly account, at least in part, for the wide normal range.Bioinformatic analysis enabled the identification of two age stable elements (ASEs) in the PZ gene promoter showing close homology to those found in two evolutionarily related proteins, human factor IX and protein C. These regions were found to be bound specifically by potentially the same or a similar protein; but the identity of the protein could not be confirmed as either PEA3 or Ets1, although transactivation data from HepG2 cells suggested PEA3 is important in controlling expression of endogenous PZ.Two further regions, proximal and distal to the PZ transcription start site, were identified by bioinformatic analysis for binding of hepatocyte nuclear factor 4 alpha (HNF4alpha), with the proximal site also reported by Sugawara and colleagues. Although both sites showed specific binding of protein only the protein binding the proximal site was confirmed as being HNF4alpha. The importance of HNF4alpha was further demonstrated by overexpression and siRNA knockdown producing a respective increase and decrease in PZ mRNA levels. Furthermore, the role of steroid hormones and inflammatory signals as potential modifiers of PZ transcription were also assessed in the HepG2 model system. This study has demonstrated, to varying degrees, the importance of tissue-specific factors (HNF4alpha), more ubiquitous factors (PEA3, Ets1), steroid hormones (oestrogen and glucocorticoid) and inflammatory pathways (bacterial LPS induction) on the regulation of PZ gene transcription

Text Enhancement in Projected Imagery

There is great interest in improving the visual quality of projectedimagery. In particular, for image enhancement, we would assertthat text and non-text regions should be enhanced differently inseeking to maximize perceived quality, since the spatial and statis-tical characteristics of text and non-text images are quite distinct.In this paper, we present a text enhancement scheme based on anovel local dynamic range statistical thresholding. Given an inputimage, text-like regions are obtained on the basis of computing thelocal statistics of regions having a high dynamic range, allowing apixel-wise classification into text-like or background classes. Theactual enhancement is obtained via class-dependent Wiener filter-ing, with text-like regions sharpened more than the background.Experimental results on four challenging images show that the pro- posed scheme offers a better visual quality than projection with- out enhancement as well as a recent state-of-the-art enhancementmethod

Training and fitness variability in elite youth soccer:perspectives from a difficulty prediction model

Research within sport science disciplines seeks to enhance performance via the combination of factors that influences the team’s periodization. The current study aimed to investigate the variations in training load (TL), and the consequential changes in fitness variables, based on the use of match difficulty prediction model (MDP), level of opposition (LOP), days between matches, and match location during 12 weeks in the competitive period I. Seventeen elite soccer players (age = 17.57 ± 0.49 years; body height 1.79 ± 0.05 m; body weight 72.21 ± 6.96 kg), have completed a Yo-Yo intermittent recovery test, a running-based anaerobic sprint test, a soccer-specific repeated sprint ability, and a vertical jump test to identify changes in players fitness. TL was determined by multiplying the RPE of the session by its duration in minutes (s-RPE). Training monotony, strain, and acute:chronic workload ratio (ACWR) were also assessed. A simple regression model was conducted and the highest variances explained (R2) were used. The LOP score explained most of the variance in ACWR (r= 0.606, R2=0.37). TL declined significantly when compared the match-day by the first three days and the last three days of the week. No significant difference was found in s-RPE between the high and low MDP factor. Strong negative correlations were reported between ACWR and LOP (r=-0.714, p<.01). In addition, we found a significant improvement in repeated sprint ability, aerobic and anaerobic fitness variables between pre- and post-test in fatigue index (d=1.104), best testing time, ideal time, total time and mean-best (d=0.518-0.550), and aerobic and anaerobic fitness variables (p<.05), respectively. The MDP could facilitate the training prescription as well as the distribution of training intensities with high specificity, providing a long-term youth player’s development and allowing teams to maintain optimal fitness leading into more difficult matches