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AIMS: Chemoattractants and their cognate receptors are essential for leucocyte recruitment during atherogenesis, and atherosclerotic plaques preferentially occur at predilection sites of the arterial wall with disturbed flow (d-flow). In profiling the endothelial expression of atypical chemoattractant receptors (ACKRs), we found that Ackr5 (CCRL2) was up-regulated in an endothelial subpopulation by atherosclerotic stimulation. We therefore investigated the role of CCRL2 and its ligand chemerin in atherosclerosis and the underlying mechanism. METHODS AND RESULTS: By analysing scRNA-seq data of the left carotid artery under d-flow and scRNA-seq datasets GSE131776 of ApoE-/- mice from the Gene Expression Omnibus database, we found that CCRL2 was up-regulated in one subpopulation of endothelial cells in response to d-flow stimulation and atherosclerosis. Using CCRL2-/-ApoE-/- mice, we showed that CCRL2 deficiency protected against plaque formation primarily in the d-flow areas of the aortic arch in ApoE-/- mice fed high-fat diet. Disturbed flow induced the expression of vascular endothelial CCRL2, recruiting chemerin, which caused leucocyte adhesion to the endothelium. Surprisingly, instead of binding to monocytic CMKLR1, chemerin was found to activate β2 integrin, enhancing ERK1/2 phosphorylation and monocyte adhesion. Moreover, chemerin was found to have protein disulfide isomerase-like enzymatic activity, which was responsible for the interaction of chemerin with β2 integrin, as identified by a Di-E-GSSG assay and a proximity ligation assay. For clinical relevance, relatively high serum levels of chemerin were found in patients with acute atherothrombotic stroke compared to healthy individuals. CONCLUSIONS: Our findings indicate that d-flow-induced CCRL2 promotes atherosclerotic plaque formation via a novel CCRL2-chemerin-β2 integrin axis, providing potential targets for the prevention or therapeutic intervention of atherosclerosis.

Epigenetic modifications play an important role in disturbed flow (d‐flow) induced atherosclerotic plaque formation. By analysing a scRNA‐seq dataset of the left carotid artery (LCA) under d‐flow conditions, we found that Jarid1b (KDM5B) was upregulated primarily in a subcluster of endothelial cells in response to d‐flow stimulation. We therefore investigated the mechanism of KDM5B expression and the role of KDM5B in endothelial cell. Intriguingly, activation of Piezo1, a major endothelial mechanosensor, was found to promote KDM5B expression, which was reversed by Piezo1 inhibition in HUVECs. Downstream of Piezo1, ETS1 expression and c‐JUN phosphorylation were enhanced by d‐flow or Piezo1 activation, leading to an increase in KDM5B expression. Furthermore, knockdown of either KDM5B or Piezo1 was found to prevent d‐flow induced H3K4me3 demethylation, which was supported by the pharmacological inhibition of Piezo1 in HUVECs. RNA sequencing on shKdm5b HUVECs implied that KDM5B is associated with endothelial inflammation and atherosclerosis. Using partial carotid ligation surgery on Kdm5bf/fCdh5cre mice with mAAV‐PCSK9D377Y infected, we showed that endothelial KDM5B deficiency reduced atherosclerotic lesions in hypercholesterolemic mice. Our findings indicate that endothelial KDM5B expression induced by d‐flow via the Piezo1 pathway promotes atherosclerotic plaque formation, providing targets for the prevention or therapeutic intervention of atherosclerosis. [ABSTRACT FROM AUTHOR]

Terahertz devices play an irreplaceable role in the development of terahertz technology. However, at present, it is difficult for most natural materials to respond in the terahertz band, making the devices made of them perform poorly. In order to realize the diversity and tunability of device functions, we designed a terahertz metamaterial device composed of the thermally-induced phase change material VO2. The device structure is composed of a Au bottom layer, a SiO2 dielectric layer and a VO2 top layer. Through software simulation, we found that when T = 313 K, the device has complete reflection ability in the whole terahertz band. When T = 342 K, the average absorptivity is above 95% in the ultra-wide band range of 4.71–9.41 THz, and the absorptivity reaches an amazing 0.99999 at 6.31 THz. Thus, the maximum thermal modulation range of the device is 0.001–0.99999. The Bruggeman effective medium theory clarifies the phase transition characteristics of vanadium dioxide. The Drude model establishes the functional relationship between the conductivity of vanadium dioxide and temperature. The basic principle of high absorption was described using the impedance matching theory. We also drew the electric field intensity diagram during the temperature rise of the device to further confirm the reason for the change in the device performance. In addition, the influence of the absence of different structural layers on the absorptivity was simulated, which reflected the role of each layer structure more intuitively. We also explored the influence of the geometric size of the device on the absorptivity, which provided a certain reference value for practical application. In short, we have designed a tunable terahertz device with simple structure, high absorptivity, and wide absorption bandwidth, which can be used in the fields of energy collection, electromagnetic stealth, and modulation. [ABSTRACT FROM AUTHOR]

Metamaterial absorbers show great potential in many scientific and technological applications by virtue of their sub-wavelength and easy-to-adjust structure, with bandwidth as an important standard to measure the performance of the absorbers. In this study, our team designed a new broadband absorber, which consists of an indium arsenide (InAs) disk at the top, a zinc selenide (ZnSe)-chromium (Cr) stacked disk in the middle and a metal film at the bottom. Simulation results show that the absorber has remarkable absorptivity properties in the mid-long infrared band. In a wavelength range of 5.71–16.01 μm, the average absorptivity is higher than 90%. In the band of 5.86–15.49 μm, the absorptivity is higher than 95%. By simulating the electromagnetic field diagram at each resonant frequency, the reason for high broadband absorptivity is obtained. We also constructed Poynting vector diagrams to further elucidate this phenomenon. Next, we analyzed the influence of different materials and structural parameters on absorptivity properties and tested spectral response at different polarization angles and oblique incidence of the light source in the TM and TE modes. When the source is normally incident, the absorber shows polarization insensitivity. When the angle is 40°, absorptivity is still high, indicating that the absorber also possesses angle insensitivity. The broadband absorber proposed by us has good prospects in infrared detection and thermal radiators. [ABSTRACT FROM AUTHOR]

In this paper, we utilize Ti and InAs materials to design a device capable of perfect solar absorption and high thermal emission efficiency. This structure is capable of generating surface plasmon resonance (SPR) and cavity resonance (CR). As this structure produces different combinations of resonances in different bands, high absorption is obtained in the full band range (280–3000 nm). The average absorption rate reaches as high as 96.7% from 280 nm to 3000 nm. The bandwidth where the absorption rate exceeds 90% measures 2720 nm (280–3000 nm). Under AM 1.5 conditions, the weighted average absorption rate is 95.8%. Additionally, this structure is insensitive to the angle of incidence. As the incident angle increases from 0° to 50°, the average absorption remains greater than 90%. Even when the incident angle is increased to 60°, the average absorption rate is 87.1%. Besides the excellent absorption performance, this structure also exhibits good thermal emission performance, with the thermal radiation efficiency reaching as high as 96.5% at 1100 K. These remarkable absorption and thermal radiation properties make this structure highly versatile, with potential applications spanning solar energy collection and radiation-related fields. [ABSTRACT FROM AUTHOR]

We report on the preparation of robust indium tin oxide (ITO) hemispherical-shell arrays (HSAs) with nanoscale thickness of ∼100 nm and their applications for passively Q-switched erbium-doped all-fiber lasers as saturable absorbers (SAs). The five different-sized ITO HSAs as robust SAs with diameters of 707, 820, 870, 994, and 1100 nm are successfully and efficiently fabricated onto the endfaces of commercial single mode fiber jumpers by using the nanosphere lithography technology. In the laser measurement, the stable Q-switched laser pulses with wavelengths centered at 1.56 μm, 3 dB bandwidths of ∼3.3 nm, and pulse widths of ∼6.44 μs are successfully obtained for all five different-sized ITO HSAs due to the larger modulation depths of ∼12.8%–16.4%, which is theoretically demonstrated to be arising from the excitations of second-order broad transverse-magnetic and transverse-electric Mie resonances. In addition, an average output power as large as 1.88 mW and single pulse energy as large as 95.46 nJ are successfully obtained for the ITO HSA SA with a diameter of 1100 nm. Our results indicate that the nanoscale thick ITO-HSA is a promising SA for constructing high performance Q-switched all-fiber lasers. [ABSTRACT FROM AUTHOR]

In recent years, absorbers related to metamaterials have been heavily investigated. In particular, VO2 materials have received focused attention, and a large number of researchers have aimed at multilayer structures. This paper presents a new concept of a three-layer simple structure with VO2 as the base, silicon dioxide as the dielectric layer, and graphene as the top layer. When VO2 is in the insulated state, the absorber is in the closed state, Δf = 1.18 THz (absorption greater than 0.9); when VO2 is in the metallic state, the absorber is open, Δf = 4.4 THz (absorption greater than 0.9), with ultra-broadband absorption. As a result of the absorption mode conversion, a phenomenon occurs with this absorber, with total transmission and total reflection occurring at 2.4 THz (A = 99.45% or 0.29%) and 6.5 THz (A = 90% or 0.24%) for different modes. Due to this absorption property, the absorber is able to achieve full-transmission and full-absorption transitions at specific frequencies. The device has great potential for applications in terahertz absorption, terahertz switching, and terahertz modulation. [ABSTRACT FROM AUTHOR]

This paper presents a photonic crystal fiber (PCF) sensor that can be used to measure the temperature and magnetic field simultaneously, and to monitor the changes in them in the environment. When we designed the fiber structure, two circular channels of the same size were added to the fiber to facilitate the subsequent addition of materials. A gold film is added to the upper channel (ch1), and the channel is filled with a magnetic fluid (MF). The sensor can reflect changes in the temperature and magnetic field strength. The two channels containing MF and PDMS in the proposed fiber are called ch1 and ch2. The structure, mode and properties (temperature and magnetic field) were analyzed and discussed using the finite element method. By using the control variable method, the influence of Ta2O5 or no Ta2O5, the Ta2O5 thickness, the diameter of the special air hole, the distance from the fiber core and the distance between them in the displacement of the loss spectrum and the phase-matching condition of the coupling mode were studied. The resulting maximum temperature sensitivity is 6.3 nm/°C (SPR peak 5), and the maximum magnetic field sensitivity is 40 nm/Oe (SPR peak 4). Because the sensor can respond to temperature and magnetic field changes in the environment, it can play an important role in special environmental monitoring, industrial production and other fields. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) still suffer from varying degrees of optical and electrical losses. To enhance the light decoupling and capture ability of Planar PSCs, an ultra-thin PSC structure with an Al2O3 pyramid anti-reflection layer (Al2O3 PARL) is proposed. The effect of the structure of the Al2O3 PARL on the photoelectric performance of PSCs was investigated by changing various parameters. Under the AM1.5 solar spectrum (300–800 nm), the average light absorption rates and quantum efficiency (QE) of PSCs containing pyramid-array textured rear layers (PARLs) were significantly higher than those of planar PSCs. The Al2O3 PARL-based PSCs achieved a light absorption rate of 96.05%. Additionally, electrical simulations were performed using the finite element method (FEM) to calculate the short-circuit current density (JSC), open-circuit voltage (VOC), and maximum power (Pmax). Based on the maximum value of the average light absorbance, the geometric structure of the Al2O3 pyramid PSCs was optimized, and the optimization results coincided with the JSC and QE results. The results of the electrical simulation indicated that the maximum JSC was 23.54 mA/cm2. Additionally, the JSC of the Al2O3 pyramid PSCs was 22.73% higher than that of planar PSCs, resulting in a photoelectric conversion efficiency (PCE) of 24.34%. As a result, the photoelectric conversion rate of the solar cells increased from 14.01% to 17.19%. These findings suggest that the presence of the Al2O3 PARL enhanced photon absorption, leading to an increase in electron–hole pairs and ultimately improving the photocurrent of the solar cells. [ABSTRACT FROM AUTHOR]