220 research outputs found

    The Growth Rate of Tidally Excited Waves in Accretion Disks

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    Accretion disks in close binary systems are subject to a tidally driven parametric instability which leads to the growth of internal waves near the outer edges of such disks (Goodman 1993). These waves are important in understanding the torque exerted on a disk by tidal forces and may play a role in the structure of the disk at small radii. Here we calculate the growth rate of this instability, including the effects of vertical structure and fluid compressibility. We find growth rates which are only slightly different from Goodman's original results, except that near the vertical resonance radius the growth rate can have an extremely broad and strong peak when the disk is stably stratified in the vertical direction. Higher order modes, in the sense of increasing number of vertical nodes, have similar growth rates. Our results differ from a previous calculation along these lines by Lubow et al. (1993). The difference is mostly due to their neglect of radial gradients in the tidally distorted streamlines.Comment: LaTeX (aastex

    Triple-Well Charge Density Wave Transition Driven by Partially Occupied Ge Electronic States in Kagome FeGe

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    Kagome materials provides a promising platform for exploring intriguing correlated phenomena. Recently, a charge density wave (CDW) order was observed in kagome antiferromagnetic metal FeGe, sparking enormous research interests in intertwining physics. Two of the core questions are (i) what drive the CDW formation in FeGe and (ii) whether it is associated with magnetism. However, previous analysis on Fe-derived van Hove singularities and Fermi nesting can't account for the CDW phase transition process and the energy minimum pristine phase well, the microscopic origin of the CDW phase in FeGe remains elusive. Here, supported by density functional theory calculations, we reveal a triple-well CDW landscape in FeGe and demonstrate it as a consequence of the reconstruction of partially occupied Ge electronic band structure, without the need for Fe-derived van Hove singularities like in non-magnetic kagome material CsV3_3Sb5_5. Moreover, we emphasize that the antiferromagnetic order, intertwined with structural distortion, is crucial for stabilizing the CDW phase. Our work thus not only deepens the understanding of the CDW mechanism in FeGe, but also indicate an intertwined connection between the emergent magnetism and CDW in kagome materials.Comment: 18 pages,3 figur

    Protective effect of Salvia miltiorrhiza in rheumatoid arthritis patients: A randomized, single-blind, placebocontrolled trial

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    Purpose: To study the protective effect of Salvia miltiorrhiza (SM) against rheumatoid arthritis (RA) in RA patients.Methods: Sixty RA patients were divided into two groups: SM (n = 30) and placebo (n =30) groups given SM at a dose of 250 mg/kg (3 capsules/day), and placebo (3 capsule/day), respectively, for 12 weeks. Patient responses based on American College of Rheumatology (ACR), health assessmentquestionnaire (HAQ) score, and global assessment of disease (GAD) were recorded. Moreover, Disease Activity Score (DAS) 28, pain score (visual analogue score, VAS), rheumatoid factor (Rh factor), and inflammatory cytokines (markers) were determined.Results: After 12 weeks of intervention with SM, ACR20 (30 %)/ACR50 patient response (13.3%, i.e., score for swelling and tenderness of joints), was significantly improved. There were considerable reductions in GAD, HAQ, DAS 28, pain score (VAS), and levels of erythrocyte sedimentation rate(ESR), acute phase reaction protein (CRP), Rh factor (IgM) and inflammatory cytokines (IL-1β, IL-6 and TNF-α), when compared to placebo (p < 0.01). Treatment with SM produced milder adverse effects than treatment with placebo (p < 0.01).Conclusion: Overall, SM produces better anti-RA effect than placebo by significantly altering ACR patient response, reducing GAD, HAQ, DAS 28 scores, Rh factor, ESR, CRP and inflammatory cytokines in RA patients. However, a large-scale clinical trial is needed before SM can be recommended for combating RA and its related symptoms. Keywords: Salvia miltiorrhiza, Rheumatoid arthritis, DAS 28, Adverse effec

    The Tungsten-Based Plasma-Facing Materials

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    The plasma-facing materials in fusion reactors will face very extreme servicing condition such as high temperatures, high thermal loads, extreme irradiation conditions induced by high-energy neutron, and high fluences of high-flux and low-energy plasma. Tungsten is considered as the most promising material for plasma-facing components (PFCs) in the magnetic confinement fusion devices, due to its high melting temperature, high thermal conductivity, low swelling, low tritium retention, and low sputtering yield. However, some important shortcomings such as the irradiation brittleness and high ductility-brittle transition temperature of pure tungsten limit its application. Focusing on this issue, various W alloys with enhanced performance have been developed. Among them, nanoparticle dispersion strengthening such as oxide particle dispersion-strengthened (ODS-W) and carbide particle dispersion-strengthened (CDS-W) tungsten alloys and W fiber-reinforced Wf/W composites are promising. This chapter mainly reviews the preparation, microstructure, properties, regulation, and service performance evaluation of ODS-W, CDS-W, and Wf/W materials, as well as future possible development is proposed

    Competing Multiferroic Phases in NiI2_{2} Mono- and Few-layers

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    A recent experiment reported type-II multiferroicity in monolayer (ML) NiI2_{2} based on a presumed spiral magnetic configuration (Spiral-B), which is, as we found here, under debate in the ML limit. Freestanding ML NiI2_{2} breaks its C3_{3} symmetry, as it prefers a striped antiferromagnetic order (AABB-AFM) along with an intralayer antiferroelectric (AFE) order. However, substrate confinement may preserve the C3_{3} symmetry and/or apply tensile strain to the ML. This leads to another spiral magnetic order (Spiral-IVXIV^X), while 2L shows a different order (Spiral-VYV^Y) and Spiral-B dominates in thicker layers. Thus, three multiferroic phases, namely, Spiral-B+FE, Spiral-IVXIV^X +FE, Spiral-VYV^Y+FE, and an anti-multiferroic AABB-AFM+AFE one, show layer-thickness-dependent and geometry-dependent dominance, ascribed to competitions among thickness-dependent Kitaev, biquadratic, and Heisenberg spin-exchange interactions and single-ion magnetic anisotropy. Our theoretical results clarify the debate on the multiferroicity of ML NiI2_{2} and shed light on the role of layer-stacking-induced changes in noncollinear spin-exchange interactions and magnetic anisotropy in thickness-dependent magnetism.Comment: 14 pages, 4 figures and an SI file of 25 pages appende

    The Silencing of RECK Gene is Associated with Promoter Hypermethylation and Poor Survival in Hepatocellular Carcinoma

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    Background: To evaluate the promoter methylation status of RECK gene and mRNA expression in patients with hepatocellular carcinoma (HCC)

    Effect of Tryptophan Hydroxylase-2 rs7305115 SNP on suicide attempts risk in major depression

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    <p>Abstract</p> <p>Background</p> <p>Suicide and major depressive disorders (MDD) are strongly associated, and genetic factors are responsible for at least part of the variability in suicide risk. We investigated whether variation at the tryptophan hydroxylase-2 (TPH2) gene rs7305115 SNP may predispose to suicide attempts in MDD.</p> <p>Methods</p> <p>We genotyped TPH2 gene rs7305115 SNP in 215 MDD patients with suicide and matched MDD patients without suicide. Differences in behavioral and personality traits according to genotypic variation were investigated by logistic regression analysis.</p> <p>Results</p> <p>There were no significant differences between MDD patients with suicide and controls in genotypic (AG and GG) frequencies for rs7305115 SNP, but the distribution of AA genotype differed significantly (14.4% vs. 29.3%, <it>p </it>< 0.001). The G-allele frequency was significantly higher in cases than control group (58.1% vs.45.6%, <it>p </it>< 0.001), but the A-allele carrier indicated a decreased trend in MDD with suicide behaviors than control group (41.9% vs.54.4%, <it>p </it>< 0.001). The multivariate logistic regression analysis indicated that TPH2 rs7305115 AA (OR 0.33, 95% CI 0.22-0.99), family history of suicide (OR 2.98, 95% CI 1.17-5.04), negative life events half year ago (OR 6.64, 95% CI 2.48-11.04) and hopelessness (OR 7.68, 95% CI 5.79-13.74) were significantly associated with the suicide behaviors in MDD patients.</p> <p>Conclusions</p> <p>The study suggested that hopelessness, negative life events and family history of suicide were risk factors of attempted suicide in MDD while the TPH2 rs7305115A remained a significant protective predictor of suicide attempts.</p

    Clinical Application of Miniature Peroneal Perforation Flap for Free Grafting In Soft Fibers of Hand, Foot and Skin

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    Objective: To study the clinical application and effect of free transplantation of miniature peroneal perforation flap in soft and tissue defects of hand, foot and skin. Method: 28 patients with hand, foot, skin and soft tissue defects who were treated in hospital from May 2015 to May 2016 were selected as the subjects. The patients were randomly divided into group A as experimental group and group B as control group. Two groups of patients with treatment site microcirculation, postoperative recovery and sensory score were compared. Results: The microcirculation indexes of group A were significantly better than those of group B (P &lt;0.05). The rate of recovery in group A was 92.86% and rate of recovery in group B was 71.43%, after treatment recovery in group A is significantly better than group B (P &lt;0.05). Before and after treatment, the sensory scores of the two groups were not statistically significant (P&gt; 0.05). The sensory score of group A was significantly higher than that of group B (P &lt;0.05). Conclusion: The microperitoneal perforation flap dissection has a good clinical effect, which can effectively improve the postoperative recovery of patients with soft tissue defects of hand, foot and skin, improve the microcirculation index of the treatment site and improve the sensory score of the treatment site, should be widely used in clinical treatment
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