Strong coupling between discrete phonon and continuous electron-hole pair excitations can induce a pronounced asymmetry in the phonon line shape, known as the Fano resonance. This effect has been ...observed in various systems. Here we reveal explicit evidence for strong coupling between an infrared-active phonon and electronic transitions near the Weyl points through the observation of a Fano resonance in the Weyl semimetal TaAs. The resulting asymmetry in the phonon line shape, conspicuous at low temperatures, diminishes continuously with increasing temperature. This behaviour originates from the suppression of electronic transitions near the Weyl points due to the decreasing occupation of electronic states below the Fermi level (E
) with increasing temperature, as well as Pauli blocking caused by thermally excited electrons above E
. Our findings not only elucidate the mechanism governing the tunable Fano resonance but also open a route for exploring exotic physical phenomena through phonon properties in Weyl semimetals.
Aim To evaluate the dynamic computed tomography (CT), magnetic resonance imaging (MRI), and clinicopathological characteristics of perivascular epithelioid cell tumours (PEComas), thus improving the ...diagnosis of the tumour. Materials and methods A retrospective analysis was undertaken of the dynamic CT, MRI, and clinicopathological characteristics of 32 PEComas diagnosed at histopathology during the period 1 January 2005 to 1 March 2012 at two hospitals. Results The age of the patients ranged from 14–80 years (mean 43.3 years). There were more women in this group (19/32). Solitary tumours were identified in kidney ( n = 16), liver ( n = 7), gynaecological organs ( n = 2), retroperitoneal soft tissue ( n = 2), lung ( n = 2), palate ( n = 1), left groin ( n = 1). One patient had multiple tumours in the liver, kidney, and retroperitoneal soft tissue. Dynamic CT (32 cases) and MRI (15 cases) demonstrated tumours that were of low density or hypointense on T1-weighted imaging (WI) and hyperintense on T2WI; some were isodense with fat (CT: 10/32; MRI: 6/15). The tumours usually had well-defined borders and were of a regular shape (CT: 26/32; MRI: 12/15). Tumour diameters ranged from 1.5–18 cm (mean 5.1 cm). Most tumours (CT: 21/32, MRI: 10/15) enhanced heterogeneously and significantly on arterial and venous phases. Tumours appeared slightly hypodense on delayed CT imaging, although some (6/32) had delayed enhancement. The expression rate of HMB-45 (human melanoma black monoclonal antibody) was 100% (32/32). Histological classification in 22 cases (22/32) was epithelioid angiomyolipoma (AML), three (3/32) were clear cell “sugar” tumours (CCSTs), two (2/32) were lymphangioleiomyomatosis (LAM), and two (2/32) were clear cell myomelanocytic tumours of the falciform ligament/ligamentum teres (CCMMT). Three tumours did not have a specific classification. Conclusion Knowledge of dynamic CT, MRI, and clinicopathological characteristics could help improve the diagnosis of PEComa.
•A coupled thermo-electric-mechanical finite element model was developed for Gleeble compression of titanium alloys.•Bulging is sensitive to temperature gradient rather than friction.•Temperature ...gradient results in underestimation of flow stress for titanium alloys.•A correction method was developed based on inverse analysis of the FE simulation.
Uniaxial compression is widely employed to investigate the constitutive behavior and microstructural developments of metallic materials at elevated temperatures. However, the heat exchange between work-piece and anvils leads to temperature gradient and inhomogeneous deformation within the work-piece, which weakens the reliability of the testing method. The problem is more serious for titanium alloys due to the poor thermal conductivity and high sensitivity of deformation resistance on temperature. To quantify the effect of temperature gradient, a coupled thermo-electric-mechanical FE model is developed for hot compression of TA15 titanium alloy with a Gleeble thermal simulator. The precise temperature control is achieved via a negative feedback control algorithm. It is found that the temperature gradient prior to deformation is sensitive to the electrical contact conductance between specimen and anvils as well as the heat transfer between the anvil and anvil base. Bulging is sensitive to temperature gradient rather than interfacial friction. The measured flow stress is smaller than the true value at large strain for the titanium alloy, which is contrary to conventional perception. Thus, the traditional flow stress correction method degrades the accuracy of flow stress measurement. A correction procedure is developed based on inverse analysis of the FE simulation. The results can reduce the systematic error of flow stress measurement of titanium alloys with Gleeble system.
In this paper, a TA2/Q235B plate was bonded with a DT4 interlayer by hot-rolling in a vacuum. The resulting interfacial structure and mechanical properties were analyzed. The results show that when ...the reduction is 25%, the rolling speed is 50mm/s, and the bonding temperature is between 750 and 850°C, the shear strength of the bonding interface increases with temperature. It is difficult to bond TA2 and DT4 at a bonding temperature of 700°C. Brittle compounds, i.e., TiC, FeTi and Fe2Ti, are formed at the interface when the bonding temperature is 950°C, and the bonding strength significantly decreases. When the bonding temperature is 850°C, the shear strength of the interface reaches a maximum of approximately 237.6MPa, and the fracture surface presents ductile fracture characteristics.
Abstract
In this work, we make use of a supervised machine-learning algorithm based on Logistic Regression (LR) to select TeV blazar candidates from the 4FGL-DR2/4LAC-DR2, 3FHL, 3HSP, and 2BIGB ...catalogs. LR constructs a hyperplane based on a selection of optimal parameters, named features, and hyperparameters whose values control the learning process and determine the values of features that a learning algorithm ends up learning, to discriminate TeV blazars from non-TeV blazars. In addition, it gives the probability (or logistic) that a source may be considered a TeV blazar candidate. Non-TeV blazars with logistics greater than 80% are considered high-confidence TeV candidates. Using this technique, we identify 40 high-confidence TeV candidates from the 4FGL-DR2/4LAC-DR2 blazars and we build the feature hyperplane to distinguish TeV and non-TeV blazars. We also calculate the hyperplanes for the 3FHL, 3HSP, and 2BIGB. Finally, we construct the broadband spectral energy distributions for the 40 candidates, testing for their detectability with various instruments. We find that seven of them are likely to be detected by existing or upcoming IACT observatories, while one could be observed with extensive air shower particle detector arrays.
ABSTRACT
The study of blazar jet has been performed for several decades via VLBI technique, while its generation and propagation stay unclear. In the present work, we compiled a sample of 407 VLBI ...detected Fermi blazars (VFBs) and studied the correlations between apparent velocity (${\rm log}\, \beta _{\rm app}$) and jet/accretion disc properties. We found a positive correlation between γ-ray luminosity (${\rm log}\, L_{\rm \gamma }$) and ${\rm log}\, \beta _{\rm app}$; the correlation suggests that the apparent motion of jet knot is related to the jet power. The correlations between ${\rm log}\, \beta ^{\rm max}_{\rm app}$ and the jet radiation power (${\rm log}\, L_{\rm rad}$), and between ${\rm log}\, \beta ^{\rm max}_{\rm app}$ and the jet extended region luminosity at 5 GHz (${\rm log}\, L_{\rm 5GHz}^{\rm ext}$), which is an indicator of jet kinetic power, reveal that the knots apparent motion is correlated with both jet radiation power and the kinetic power. But this indication is not held for flat-spectrum radio quasar (FSRQs) in terms of the correlation ${\rm log}\, L_{\rm 5GHz}^{\rm ext}\, versus \, {\rm log}\, \beta ^{\rm max}_{\rm app}$. Besides, ${\rm log}\, \beta ^{\rm max}_{\rm app}$ has a moderate correlation with accretion disc luminosity (${\rm log}\, L_{\rm Disk}$) and the normalized accretion disc luminosity ${\rm log}\, (L_{\rm Disk}/L_{\rm Edd})$, which may suggest both the power of accretion disc and the accretion rate are critical to generate knots and to accelerate them. In addition, we found the VFBs have larger average values of γ-ray luminosity (${\rm log}\, L_{\rm \gamma }$), γ-ray photon index (αph), and variability index (${\rm log}\, VI$) than the rest of Fermi blazars. Through Gaussian mixture models method, we generated a criteria, ${\rm log}\, L_{\rm \gamma } \gt 45.40$, αph > 2.24, and ${\rm log}\, VI \gt 1.71$ to find VFB candidates, selected 228 VFB candidates from the rest of Fermi blazar.
Summary
Background
Vitamin D may play important roles in regulating immune responses and in defence against infectious diseases by effects on both innate and adaptive immune responses. Little is ...known regarding activation of vitamin D within airway tissues and its relationship to inflammation and antimicrobial responses.
Objective
The objective of this study was to investigate the activation of vitamin D within the airways and to define relationships between vitamin D metabolites and measures of inflammatory and antimicrobial responses assessed by bronchoalveolar lavage (BAL) during late‐phase responses following allergen challenge of allergic subjects.
Methods
Segmental allergen challenge was performed with saline and allergen in 16 adult allergic subjects. BAL was performed in both saline and allergen‐challenged sites 20–24 h. after challenge. Following extraction from BAL fluids, levels of 25‐hydroxy‐vitamin D (25(OH)D) and 1,25‐dihydroxy‐vitamin D (1,25(OH)2D) were assayed by specific radioimmunoassays. The cleavage product of cathelicidin, LL‐37, was assayed by ELISA. Cellular constituents and albumin were measured.
Results
Levels of vitamin D metabolites were increased in concentrated BAL fluids after allergen compared to saline challenge. Levels of 1,25(OH)2D increased from largely undetectable to 2.5 pm (median; range: 1–29.5; P = 0.005) while 25(OH)D increased from 3.2 (0.8–6.2) to 6.2 (1.5–184.9) nm (P = 0.0006). Levels of LL‐37 increased from 2.1 (1.4–4.1) to 14.5 (2.2–106.7) ng/mL BAL (P = 0.0005). Levels of LL‐37, 1,25(OH)2D, and 25(OH)D following allergen challenge were correlated with each other (P < 0.0001), cellular changes, and levels of albumin (P < 0.001).
Conclusions and Clinical Relevance
Levels of vitamin D metabolites, particularly 1,25(OH)2D, were low within the airways and increased after allergen challenge. The increases correlated with the magnitude of inflammation and increases in cathelicidin. Normalization to albumin suggested plasma exudation as a mechanism for the increases. The findings support a role for vitamin D in allergic and innate immune responses in the lung.
The dissolved carbon concentration, which is responsible for aquatic ecosystem productivity and water quality, is tightly coupled with hydrological processes. Excess dissolved carbon may exacerbate ...eutrophication and hypoxia in aquatic ecosystems and lead to deterioration of water quality. Storm events dominate the dynamics of dissolved carbon concentrations, and this nonlinear behavior exhibits significant time scale dependence. Here, we identified inter- and intra-event variability in the dissolved carbon concentration–discharge (C–Q) relationship in an agriculture-intensive catchment. The driving factors of C–Q hysteresis patterns for dissolved inorganic carbon (DIC) and organic carbon (DOC) were quantified by redundancy analysis combined with hierarchical partitioning. At the inter-event scale, DIC exhibited mainly clockwise hysteresis, indicating an exhaustible, proximal source (e.g., groundwater). However, DOC hysteresis was generally counter-clockwise, indicating distal and plentiful sources (e.g., soil water) in the agricultural catchment. Hierarchical partitioning showed that total rainfall, peak discharge and flood intensity explained 28.38% of the total variation in C–Q hysteresis for DIC and 39.87% for DOC at the inter-event scale. At the intra-event scale, time series analysis of dissolved carbon concentration and discharge indicated the interconversion of supply limitation to transport limitation, which depends on the activation of the specific DIC or DOC source zones. These findings provide significant insights into understanding the dynamics of dissolved carbon during storm periods and are important for targeted watershed management practices aimed at reducing carbon loading to surface waters.
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Vanadium is considered as “possibly carcinogenic to humans” (V2O5, IARC Group 2B), yet uncertainties persist related to the toxicity mechanisms of the multiple forms of vanadium. Exposure to vanadium ...often co-occurs with other metals or with organic compounds that can be transformed by cytochrome p450 (CYP) enzymes into DNA-reactive carcinogens. Therefore, effects of a soluble form of vanadium (sodium metavanadate, NaVO3) and aflatoxin-B1 (AFB1) were tested separately and together, for induction of CYP activities, DNA damage (γH2AX and DNA alkaline unwinding assays), and DNA methylation changes (global genome and DNA repeats) in HepaRG or HepG2 liver cell lines. NaVO3 (≥ 2.3 μM) reduced CYP1A1 and CYP3A4 activities and induced DNA damage, butcaused important cell proliferation only in HepaRG cells. As a binary mixture, NaVO3 did not modify the effects of AFB1. There was no reproducible effect of NaVO3 (<21 μM) on DNA methylation in AluYb8, satellite-α, satellite-2, and by the luminometric methylation assay, but DNA methylation flow-cytometry signals in HepG2 cells (25–50 μM) increased at the G1 and G2 cell cycle phases. In conclusion, cell lines responded differently to NaVO3 supporting the importance of investigating more than one cell line, and a carcinogenic role of NaVO3 might reside at low concentrations by stimulating the proliferation of tumorigenic cells.
•Hepatic cell lines responded differently to NaVO3.•NaVO3 (<10 μM) stimulated proliferation of HepaRG but not HepG2 cells.•NaVO3 (<21 μM) had no effect on DNA methylation (AluYb8, satellite-α, sat-2, LUMA).•NaVO3 (25–50 μM) increased DNA methylation in HepG2 cells by flow-cytometry.•Proliferation induction (<10 μM) warrants carcinogenic risk assessment consideration.
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