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Atherosclerotic plaque formation is largely attributed to the impaired efferocytosis, which is known to be associated with the pathologic upregulation of cluster of differentiation 47 (CD47), a key antiphagocytic molecule. By gene expression omnibus (GEO) datasets analysis, we identified that four miRNAs are aberrantly downregulated in atherosclerosis, coronary artery disease, and obesity. Of them, hsa‐miR‐299‐3p (miR‐299‐3p) was predicted to target the 3′UTR of human CD47 mRNA by bioinformatics analysis. Further, we demonstrated that miR‐299‐3p negatively regulates CD47 expression by binding to the target sequence "CCCACAU" in the 3′UTR of CD47 mRNA through luciferase reporter assay and site‐directed mutagenesis. Additionally, we found that miR‐299‐3p was downregulated by ~32% in foam cells in response to oxidized low‐density lipoprotein (ox‐LDL) stimulation, thus upregulating CD47 and contributing to the impaired efferocytosis. Whereas, restoration of miR‐299‐3p reversed the ox‐LDL‐induced upregulation of CD47, thereby facilitating efferocytosis. In high‐fat diet (HFD) fed ApoE−/− mice, we discovered that miR‐299‐3p was downregulated thus leading to upregulation of CD47 in abdominal aorta. Conversely, miR‐299‐3p restoration potently suppressed HFD‐induced upregulation of CD47 and promoted phagocytosis of foam cells by macrophages in atherosclerotic plaques, thereby reducing necrotic core, increasing plaque stability, and mitigating atherosclerosis. Conclusively, we identify miR‐299‐3p as a negative regulator of CD47, and reveal a molecular mechanism whereby the ox‐LDL‐induced downregulation of miR‐299‐3p leads to the upregulation of CD47 in foam cells thus contributing to the impaired efferocytosis in atherosclerosis, and propose miR‐299‐3p can potentially serve as an inhibitor of CD47 to promote efferocytosis and ameliorate atherosclerosis. [ABSTRACT FROM AUTHOR]

So far, developed microwave absorbers exhibit significant changes in absorption with temperature, which hinder their operation within a wide temperature range. In this paper, a microwave absorber based on SiBCN ceramics was prepared. Due to the excellent high‐temperature stability of SiBCN ceramics, its permittivity changes less with temperature, avoiding the issue of performance deterioration or even failure that traditional refractory absorbers face at high temperatures. The experiment proves the absorption bandwidth for –15 dB of the SiBCN metamaterials absorber (SMA) is 12 GHz at 800°C, with a maximum absorptivity of 99.99%. According to the computed data, the resonance loss contributes 81.9 to 94.5% of the microwave absorption of SMA. This work demonstrates significant potential for applications in radar stealth under harsh conditions. [ABSTRACT FROM AUTHOR]

Although human pluripotent stem cell (PSC)‐derived brain organoids have enabled researchers to gain insight into human brain development and disease, these organoids contain solely ectodermal cells and are not vascularized as occurs during brain development. Here it is created less complex and more homogenous large neural constructs starting from PSC‐derived neuroprogenitor cells (NPC), by fusing small NPC spheroids into so‐called concentroids. Such concentroids consisted of a pro‐angiogenic core, containing neuronal and outer radial glia cells, surrounded by an astroglia‐dense outer layer. Incorporating PSC‐derived endothelial cells (EC) around and/or in the concentroids promoted vascularization, accompanied by differential outgrowth and differentiation of neuronal and astroglia cells, as well as the development of ectodermal‐derived pericyte‐like mural cells co‐localizing with EC networks. Single nucleus transcriptomic analysis revealed an enhanced neural cell subtype maturation and diversity in EC‐containing concentroids, which better resemble the fetal human brain compared to classical organoids or NPC‐only concentroids. This PSC‐derived "vascularized" concentroid brain model will facilitate the study of neurovascular/blood‐brain barrier development, neural cell migration, and the development of effective in vitro vascularization strategies of brain mimics. [ABSTRACT FROM AUTHOR]

The nonstationary roles of regional forcings from alongshore wind stress and sea level pressure (SLP) in driving low‐frequency (interannual‐to‐decadal) sea level variability along the U.S. east coast for the 1959–2020 period are investigated. The role of regional forcings increases with time north of Cape Hatteras particularly during summer when their contributions to the variance of observed summertime coastal sea level anomalies increase by approximately 58%–87% from 1959–1989 to 1990–2020. The enhanced impact of regional forcings in recent decades results from an increase in the Inverted Barometer (IB) effect that act constructively with alongshore wind stress especially during summer, and to a lesser extent for the Gulf of Maine during fall. The summertime North Atlantic Oscillation (NAO) is largely responsible for the increased IB effect, owing to the stronger NAO‐associated low SLP anomalies centered around the Mid‐Atlantic Bight in recent decades compared to earlier decades. Plain Language Summary: Alongshore wind stress and sea level pressure (SLP) are important regional forces in driving low‐frequency (interannual‐to‐decadal) sea level anomalies along the U.S. east coast. The roles of these regional forcings, however, vary with time, season, and region, which can shift the location and change the frequency and intensity of coastal flooding. In this study, we find that regional forcings contribute more to observed sea level variability north of Cape Hatteras in recent decades (1990–2020) compared to earlier decades (1959–1989), particularly during summer. The increased role of regional forcings results from SLP variability via the Inverted Barometer (IB) effect, which exhibits a significant upward trend during summer with lower (higher) SLP raising (suppressing) sea level. The North Atlantic Oscillation (NAO) is largely responsible for the increased role of IB effect because the lower SLP anomalies related to the NAO have become more prominent north of Cape Hatteras in recent decades. Although winter NAO has been shown to be important for affecting the coastal sea level anomalies, it is the summer NAO effect that is enhanced via the IB effect, accounting for the enhanced regional forcing in recent decades. Key Points: The sea‐level variance explained by regional forcings increases with time north of Cape Hatteras due to the Inverted Barometer effectLower sea level pressure centered around Mid‐Atlantic Bight favors more contributions of the Inverted Barometer effect in recent decadesThe summertime North Atlantic Oscillation is largely responsible for the increased role of the Inverted Barometer effect [ABSTRACT FROM AUTHOR]

B4C ceramics have been widely used in armor plate and cutting tools due to their high hardness. However, their poor sintering performance and low fracture toughness have limited their extended applications. In order to solve these problems, B4C@TiB2 composite powders with core–shell structure were prepared by a sol–gel method using B4C and TiCl4 as raw materials and then sintered by spark plasma sintering. The composite powders were characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, and scanning electron microscopy. The mechanical properties of B4C ceramics were tested by indentation and three‐point bending methods. The results showed that the B4C@TiB2 composite powders exhibited a tight core–shell structure, and the chemical bonds on the surface were mainly B–C and B–Ti bonds. When the molar ratio of B4C:TiCl4 was 2:1, the relative density and bulk density of B4C ceramics reached 96.2% and 2.92 g/cm3, respectively. Because of the good sintering performance of the B4C@TiB2 composite powders, the Vickers hardness and fracture toughness reached 26.6 GPa and 5.22 MPa m1/2, respectively. The bending strength reached a maximum of 570 MPa. The excellent fracture toughness can be attributed to crack deflection, crack branching, and the residual thermal stress of the core–shell structure. [ABSTRACT FROM AUTHOR]

Excellent thermostable performance is the basis for the further development of microwave absorbing materials in the field of military stealth. Herein, a high‐temperature metamaterial absorber (HMA) with high impedance patterns (multi‐octagonal‐rings), two quartz (SiO2) layers, and a metallic ground film is designed and simulated. The optimal structural parameters are obtained by optimizing the circuit parameters and the size of HMA. The interaction of electric and magnetic resonance in multioctagonal rings results in a wide absorption bandwidth and excellent absorption performance. The experimental results show that the structure has good impedance matching performance, and the effective absorption bandwidth (−10 dB) (EAB) of the structure can reach 10.6 GHz from room temperature to 700 °C under the combined effect of resonance loss and ohmic loss. [ABSTRACT FROM AUTHOR]

A broadband metamaterial absorber (MA) with high‐temperature resistance is designed and fabricated using a regular octagonal ring‐cross structure as a frequency‐selective surface (FSS). A high‐temperature conductive paste and SiO2 are used as the FSS raw materials and middle layer, respectively. Simulation and experimental results show that the absorber reaches a reflection loss below −5 dB at the 5.17–18 GHz range with normal incidence at room temperature. The measured values are in good agreement with the simulation results. At 800 °C, the absorption bandwidth expands to 13.3 GHz (4.72–18 GHz). The equivalent impedance of the absorber is obtained using an inversion method to qualitatively explain its working mechanism. The electric energy density, magnetic energy density, and surface current at the resonance frequency provide an intuitive understanding of the power loss of the structure. Comprehensive analysis illustrates that the main absorption mechanisms of the high‐temperature broadband MA (HBMA) are ohmic and resonance losses. [ABSTRACT FROM AUTHOR]

Global mean sea level (GMSL) has been rising since the last century, posing a serious challenge for the coastal areas. A variety of regression models have been utilized for determining GMSL rise over the past one hundred years, resulting in a large spread of sea level rise rates and multidecadal variations. In this study, we develop a new nonparametric noise model that is data‐dependent and considers overfitting due to regression. The noise model is used to determine whether one regression model has significantly better skill than others over the period 1900–2010. The choices of background noise and GMSL reconstruction influence whether two sea level models can be statistically distinguished. With our new nonparametric noise spectra, the differences of model skills in explaining sea level variance are significant only in 34% of model comparisons. However, stepwise trends with three inflection points are significantly more skillful than the linear, quadratic, or exponential trend for most GMSL reconstructions, suggesting the importance of multidecadal variability of sea level rise in the twentieth century. Nevertheless, stepwise trend models cannot be distinguished from models with a long‐term harmonic oscillation, indicating that the shape of multidecadal variability is not conclusive. The multidecadal variability is also significant in the steric and barystatic sea level contributions and is related to both natural and anthropogenic forcings. GMSL predictions based on regression fits in the twentieth century underestimate the sea level rise rate over the period 2011–2020 because the sea level acceleration in the recent decade (2011–2020) is not well represented. Plain Language Summary: Global mean sea level (GMSL) has been rising since the last century under a warming climate. Understanding both the mean rate and how it is accelerating is important for future management of coastal areas. Various regression models have typically been used to detect the rates of sea level change. As different regression models imply different rates and their consequences for future sea level projections are very different, it is important to distinguish their skills in explaining sea level variance. In addition, different GMSL time series estimated from historical tide‐gauge data also imply different rise rates and long‐term variations. In this study, we develop a new noise model that is data‐dependent and considers the underestimation of noise energy due to regression. Based on the new noise model, comparisons between different regression models indicate that the exact shape of sea level change cannot be determined with any confidence. Nevertheless, the multidecadal variability of sea level rise is significant in the GMSL. Cautions must be taken when regression models are used to predict the GMSL rise because regression fits to the GMSL in the twentieth century underestimate the sea level rise in the recent decade (2011–2020). Key Points: A new nonparametric noise model is developed to distinguish skills of regression models for global mean sea levelAn accurate estimate of background noise and global mean sea level reconstruction is important for distinguishing sea level modelsThe multidecadal variability of sea level rise is significant, but its exact shape is not conclusive over the period 1900–2010 [ABSTRACT FROM AUTHOR]

Earlier studies in the Northeast Pacific (NEP) suggest that the local and remote sea level responses are important for the large‐scale, low‐frequency sea level variability, but the relative importance of the two processes remains unclear. In this study, we develop a novel sea level model driven by wind, buoyancy and eddy forcing to examine their relative roles in the NEP. Based on the new model, a diagnostic equation for sea level that is an alternative to the conventional method of characteristics is formed. The wind, buoyancy and eddy forcing account for the sea level variability in different regions. Sea level variability is primarily controlled by the wind forcing in the central to the northeast of the NEP, by the local buoyancy forcing in the southeast region between 210°E and 230°E, and by the eddy forcing in the southwest of the NEP. In addition, the diagnosis demonstrates that the local sea level response is more important than the remote response over most of the NEP, while the remote sea level response could play an important role in the southwest portion of the NEP. Plain Language Summary: In the Northeast Pacific (NEP), the low‐frequency sea level variability is not only an important component for predicting the future sea level change but also an integrated measure of climate variability over this region. It can respond to the local and remote external forcing. However, the importance of different driving forces and the relative role of the local and remote sea level response in determining the low‐frequency sea level variability are not conclusive. In this study, the sea level variability is diagnosed with a new developed sea level model. Winds, surface heat and freshwater fluxes and intense eddy activities contribute to the sea level variability in different regions. Sea level variability is primarily driven by the winds in the central to the northeast of the NEP, by the local surface heat and freshwater fluxes in the southeast of the NEP, and by the eddy forcing in the southwest of the NEP. Moreover, our results suggest that the local sea level response is more important than the remote sea level response over most of the NEP. Key Points: A new sea level model driven by wind, buoyancy and eddy forcing is proposedWind, buoyancy and eddy forcing account for the sea level variability in different regions of the Northeast PacificThe local sea level response is more important than the remote response over most of the Northeast Pacific except in the southwest [ABSTRACT FROM AUTHOR]

Numerical circulation modeling and observational studies have been conducted to understand the Loop Current (LC) system behaviors in the Gulf of Mexico (GoM). One of the factors that may influence the LC are upstream eddies from within the Caribbean Sea. By combining satellite altimetry, sea surface salinity and ocean color data, we demonstrate that mesoscale eddies from the western tropical Atlantic Ocean can eventually make their way to the Gulf of Mexico and likely affect the LC. In addition, our study shows that freshwater of Amazon and Orinoco River origin trapped within mesoscale eddies can also enter the GoM, potentially affecting the GoM stratification. This study provides insights into understanding variations of the LC system and showcases the roles of mesoscale eddies in connecting the open ocean and regional seas. Plain Language Summary: The Loop Current (LC) is the dominant large‐scale oceanic process in the Gulf of Mexico (GoM). However, the mechanism for variations of the LC system is still unsolved. Here, we show that some mesoscale eddies originated in the tropical Atlantic Ocean can pass through the Caribbean Sea and eventually enter the GoM. These remotely generated eddies could be an important upstream factor affecting the behavior of the LC. Also, freshwater and other materials (e.g., chlorophyll) trapped in the eddies could reach the GoM as well. In addition to advancing the understanding of the LC system, this study provides an explicit example showing eddies can serve as a route connecting regional seas and the open ocean. Key Points: Some eddies from the Atlantic Ocean can ultimately reach the Gulf of Mexico and likely affect the Loop CurrentFreshwater of Amazon and Orinoco River origin and other materials trapped in eddies could reach the Gulf of MexicoWeakening and strengthening of the long‐propagating eddies are mostly related to the variation of bathymetry [ABSTRACT FROM AUTHOR]

Coupling between the surface and near‐bottom currents in the Gulf of Mexico (GoM) has been reported in many case studies. However, geographical variations of this coupling need more examination. In this study, surface geostrophic currents derived from satellite‐observed sea surface height and subsurface currents from a collection of deep ocean moorings are used to examine the surface and bottom coupling in different parts of the GoM. The short‐period (30–90 days) fluctuations generated by the Loop Current (LC) and the LC eddies (LCEs) have a more vertically coherent structure and stronger deep ocean expressions than the long‐period fluctuations (>90 days). In addition, the strength of the coupling is modulated by the long‐period variations of the LC and LCE sheddings. Moreover, the surface and bottom coupling varies geographically. In the LC region, the surface fluctuations along the eastern side of the LC are important in causing the bottom current fluctuations through baroclinic instability under the LC and through traveling topographic Rossby waves (TRWs) north of the LC. In the central deep GoM, the bottom currents are affected by the upper fluctuations of the northern LC through both local baroclinic instability and remote TRW propagation. In the northwestern GoM, the bottom current fluctuations are largely related to the remote surface variability from the west side of the LC by TRWs propagating northwestward. This study will help us better understand mechanisms of the bottom current fluctuations that are important for the dispersal of deep ocean materials and properties. Plain Language Summary: Bottom currents in the Gulf of Mexico (GoM) are important in many ways, such as transporting fish larvae and spilled oil. However, in contrast to surface currents that are easily derived from the abundant satellite observations, our understanding of the bottom currents is very limited. In this study, the relationships between surface and near‐bottom current fluctuations in different parts of the GoM are investigated by combining a collection of historical near‐bottom current measurements and satellite data. The results show that the bottom current variability is linked to local processes such as current instability or remote processes through planetary wave propagation. The surface and bottom coupling is mainly related to the short‐period variability generated along the Loop Current and the Loop Current eddies and has a significant influence on the bottom currents. Although the long‐period fluctuations have weak bottom expressions, they can modulate the strength of the short‐period coupling. Studying the coupling between the surface and bottom current fluctuations in the GoM can advance our understanding of mechanisms of the bottom currents that are important for the deep ocean ecosystem and industrial operations. Key Points: Surface and bottom currents in the Gulf of Mexico can be coupled locally by baroclinic instability and remotely by topographic Rossby wavesFluctuations generated along the Loop Current have stronger deep ocean expressions at the period of 30–90 days than at longer periodsSurface and bottom coupling in the Gulf of Mexico varies geographically and is modulated by the Loop Current and the Loop Current eddies [ABSTRACT FROM AUTHOR]

A series of Ce3+ and Tb3+ singly‐ and co‐doped NaBa4(AlB4O9)2Cl3 (NBAC) phosphors have been synthesized via high‐temperature solid state route. The crystal structure, morphology, photoluminescent properties, thermal properties and energy transfer process between Ce3+ and Tb3+ were systematically investigated. The structure refinements indicated that the phosphors based on NBAC crystallized in P42nm polar space group in monoclinic phase. The emission color could be tuned from blue (0.1595, 0.0955) to green (0.2689, 0.4334) via changing the ratio of Ce3+/Tb3+. The energy transfer mechanism of Ce3+/Tb3+ was verified to be dipole–quadrupole interaction via the examination of decay times of Ce3+ based on Dexter's theory. The good thermal stability showed the intensities of Ce3+ at 150°C were about 66.9% and 64.88% in NBAC:0.09Ce3+ and NBAC:0.09Ce3+, 0.07Tb3+ of that at room temperature, and the emission intensities of Tb3+ remained 102.41% in NBAC:0.11Tb3+ and 95.22% in NBAC:0.09Ce3+, 0.07Tb3+ due to the nephelauxetic shielding effect and the highly asymmetric rigid framework structure of NBAC. The maximum external quantum efficiency (EQE) of Ce3+ in NBAC:0.09Ce3+, yTb3+ phosphors could reach 43.38% at y = 0.13. Overall, all the results obtained suggested that NBAC:Ce3+, Tb3+ could be a promising option for n‐UV pumped phosphors. [ABSTRACT FROM AUTHOR]

Abstract: Charge compensation was the effective methods to enhance the luminescence properties of phosphors. In this paper, novel single‐phased orange light emitting Sr2Mg3P4O15:Eu3+ phosphors were prepared by solid state method. The phase purity and luminous characteristics were examined in detail. Meanwhile, three kinds of charge compensation methods (co‐doping the alkali metal R+ (R+ = Li, Na, and K), substituting Si4+ for P5+ and self‐compensation) were employed to solve the charge imbalance problem between Sr2+ and Eu3+. The results showed that emission intensity of Eu3+ was improved by 1.43 (Li+), 1.58 (Na+), 1.53 (K+), 1.61 (Si4+), and 1.30 (self) times than that of Sr1.6Mg3P4O15:0.40Eu3+, respectively, and there was no change in the emitting color simultaneously. Furthermore, as the temperature reached at 423 K, the emission intensity increased from 41.67% of Sr1.6Mg3P4O15:0.40Eu3+ to 55.69% (Li+), 61.62% (Na+), 58.98% (K+), 71.15% (Si4+), and 80.59% (self) of that at room temperature. The reasons of those phenomena were the reduction in ion vacancies caused by charge imbalance through the charge compensation process. The specific mechanisms were elaborated in detail. Overall, this research validated that the charge compensation strategies could be severed as the key method to improve the luminescence properties, especially the thermal stability of phosphor. [ABSTRACT FROM AUTHOR]

The narrow‐band emitting phosphors have been extensively investigated in recent years, with the expectation that a wide color gamut of phosphor‐converted backlighting device could be fabricated. Due to the weak electric–phonon interaction and low structural relaxation caused by the high rigid crystal structure and symmetric coordination environment, Sr2MgAl22O36:Mn2+ (SMAO:Mn2+) shows a narrow full‐width at half‐maximum of 26 nm, a high color purity of 81.5%, and a low thermal quenching (82% at 473 K of the initial intensity at 298 K). Using K2SiF6:Mn4+ as the red phosphor, SMAO:Mn2+ as the green one, and GaN‐based chip as the blue component, the white light‐emitting diode exhibits a National Television Standard Committee value of 127%. All the results demonstrate that the SMAO:Mn2+ phosphor has a promising application in the field of advanced wide‐color‐gamut backlight display, and the establishment of the relationships between the narrow‐band emission and crystal structure can also be applied to design other novel narrow‐band phosphors for backlighting technologies. A novel narrow‐band green‐emitting phosphor Sr2MgAl22O36:Mn2+ with peak position at 518 nm, full‐width at half‐maximum of 26 nm, and a low thermal quenching at high temperature (82% of room temperature intensity at 498 K) under the excitation of blue light‐emitting diode chip is discovered. These good luminesce properties are benefited from the high rigid crystal structure and symmetric coordination environment. [ABSTRACT FROM AUTHOR]

Abstract: Charge compensation was the effective methods to enhance the luminescence properties of phosphors. In this paper, novel single‐phased orange light emitting Sr2Mg3P4O15:Eu3+ phosphors were prepared by solid state method. The phase purity and luminous characteristics were examined in detail. Meanwhile, three kinds of charge compensation methods (co‐doping the alkali metal R+ (R+ = Li, Na, and K), substituting Si4+ for P5+ and self‐compensation) were employed to solve the charge imbalance problem between Sr2+ and Eu3+. The results showed that emission intensity of Eu3+ was improved by 1.43 (Li+), 1.58 (Na+), 1.53 (K+), 1.61 (Si4+), and 1.30 (self) times than that of Sr1.6Mg3P4O15:0.40Eu3+, respectively, and there was no change in the emitting color simultaneously. Furthermore, as the temperature reached at 423 K, the emission intensity increased from 41.67% of Sr1.6Mg3P4O15:0.40Eu3+ to 55.69% (Li+), 61.62% (Na+), 58.98% (K+), 71.15% (Si4+), and 80.59% (self) of that at room temperature. The reasons of those phenomena were the reduction in ion vacancies caused by charge imbalance through the charge compensation process. The specific mechanisms were elaborated in detail. Overall, this research validated that the charge compensation strategies could be severed as the key method to improve the luminescence properties, especially the thermal stability of phosphor. [ABSTRACT FROM AUTHOR]