The development of advanced dielectric materials with high breakdown strength, high dischargeable energy densities, and great efficiencies is imperative to meet the ever-increasing demand of modern power systems and electronic devices. Herein, we present the layer-by-layer solution prepared bilayer-structured nanocomposite films with much enhanced capacitive performance via resolving the typical paradox between dielectric constant and breakdown strength in dielectric materials. The bilayered nanocomposite films are composed of Al2O3 dispersed in polystyrene as the interfacial barrier layer to inhibit electrical conduction and the polystyrene layer with TiO2 to enhance dielectric constant. The resulting layered film exhibits a discharged energy density of 4.43 J/cm3 along with ultrahigh charge−discharge efficiencies of >90%, which is among the highest energy densities ever achieved in the polystyrene-based dielectric polymer nanocomposites. In addition, the composite films show outstanding cyclic stability under high electric fields, which would enable the long-term efficient operation of film capacitors. This contribution represents an efficient route to high-energy-density dielectric composite materials by using interfacial barrier architectures.

The introduction of inorganic components into a polymer matrix to form polymer composites is an emerging and promising approach to dielectric materials for capacitive energy storage. Ferroelectric polymers are particularly attractive as matrices for dielectric polymer composites owing to their highest dielectric constant (≥10) among the known polymers. Here, the important aspects and recent advances in the development of the ferroelectric-polymer-based dielectric polymer composites for high-energy-density capacitor applications are summarized. The preparation methods of ferroelectric-polymer composites with 0D, 1D, and 2D nanostructured fillers, surface-modified nanofillers, and hierarchically structured fillers, and their comprehensive impacts on the dielectric properties, breakdown strength, and energy density of the resulting composites are described. The most recent progress on the incorporation of multiple nanofillers with complementary functionalities into ferroelectric polymers and the design of layer-structured ferroelectric-polymer composites is also highlighted. A discussion of the scientific and technological issues that remain to be addressed and an outlook for the future of ferroelectric polymer-based dielectric composites are also presented.

The exploration of high-energy-density electrostatic capacitors capable of operating both efficiently and reliably at elevated temperatures is of great significance in order to meet advanced power electronic applications. The energy density of a capacitor is strongly dependent on dielectric constant and breakdown strength of a dielectric material. Here, we demonstrate a class of solution-processable polymer nanocomposites exhibiting a concurrent improvement in dielectric constant and breakdown strength, which typically show a negative correlation in conventional dielectric materials, along with a reduction in dielectric loss. The excellent performance is enabled by the elegant combination of nanostructured barium titanate and boron nitride fillers with complementary functionalities. The ternary polymer nanocomposite with the optimized filler compositions delivers a discharged energy density of 2.92 J cm−3 and a Weibull breakdown strength of 547 MV m−1 at 150°C, which are 83% and 25%, respectively, greater than those of the pristine polymer. The conduction behaviors including interfacial barrier and carrier transport process have been investigated to rationalize the energy storage performance of ternary polymer nanocomposite. This contribution provides a new design paradigm for scalable high-temperature polymer film capacitors. (Figure presented.).

Arachidonic acid-derived epoxyeicosatrienoic acids (EETs) are important regulators of cardiac remodeling; manipulation of their levels is a potentially useful pharmacological strategy. EETs are hydrolyzed by soluble epoxide hydrolase (sEH) to form the corresponding diols, thus altering and reducing the activity of these oxylipins. To better understand the phenotypic impact of sEH disruption, we compared the effect of EPHX2 gene knockout (EPHX2-/-) and sEH inhibition in mouse models. Measurement of plasma oxylipin profiles confirmed that the ratio of EETs/DHETs was increased in EPHX2-/- and sEH-inhibited mice. However, plasma concentrations of 9, 11, 15, 19-HETE were elevated in EPHX2-/- but not sEH-inhibited mice. Next, we investigated the role of this difference in cardiac dysfunction induced by Angiotensin II (AngII). Both EPHX2 gene deletion and inhibition protected against AngII-induced cardiac hypertrophy. Interestingly, cardiac dysfunction was attenuated by sEH inhibition rather than gene deletion. Histochemical staining revealed that compared with pharmacological inhibition, EPHX2 deletion aggravated AngII-induced myocardial fibrosis; the mRNA levels of fibrotic-related genes were increased. Furthermore, cardiac inflammatory response was greater in EPHX2-/- than sEH-inhibited mice with AngII treatment, as evidenced by increased macrophage infiltration and expression of MCP-1 and IL-6. In vitro, AngII-upregulated MCP-1 and IL-6 expression was significantly attenuated by sEH inhibition but promoted by EPHX2 deletion in cardiofibroblasts. Thus, compared with pharmacological inhibition of sEH, EPHX2 deletion caused the shift in arachidonic acid metabolism, which may led to pathological cardiac remodeling, especially cardiac fibrosis.

The electrification of transport requires dielectric materials capable of operating efficiently at high temperatures to meet the increasing demand of electrical energy storage at extreme conditions. Current high-temperature dielectric polymers rely on the incorporation of wide bandgap inorganic fillers to restrain electrical conduction and achieve high efficiencies at elevated temperatures. Here, we report a new class of all-polymer based high-temperature dielectric materials prepared from crosslinking of melt-processable fluoropolymers. The crosslinked polymers exhibit larger discharged energy densities and greater charge-discharge efficiencies along with excellent breakdown strength and cyclic stability at elevated temperatures when compared to the current dielectric polymers. The origins of the marked improvement in the high-temperature capacitive performance are traced to efficient charge-trapping by a range of the molecular trapping centers resulting from the crosslinked structures. In addition, the implementation of melt-extrudable polymers would enable scalable processing that is compatible with the current fabrication techniques used for polymer dielectrics, which is in sharp contrast to the dielectric polymer composites with inorganic fillers.

Next-generation microelectronics and electrical power systems call for high-energy-density dielectric polymeric materials that can operate efficiently under elevated temperatures. However, the currently available polymer dielectrics are limited to relatively low working temperatures. Here, the solution-processable polymer nanocomposites consisting of readily prepared Al₂ O₃ fillers with systematically varied morphologies including nanoparticles, nanowires, and nanoplates are reported. The field-dependent electrical conduction of the polymer nanocomposites at elevated temperatures is investigated. A strong dependence of the conduction behavior and breakdown strength of the polymer composites on the filler morphology is revealed experimentally and is further rationalized via computations. The polymer composites containing Al₂ O₃ nanoplates display a record capacitive performance, e.g., a discharged energy density of 3.31 J cm^-3 and a charge-discharge efficiency of >90% measured at 450 MV m^-1 and 150 °C, significantly outperforming the state-of-the-art dielectric polymers and nanocomposites that are typically prepared via tedious, low-yield approaches.

Modern electronics and electrical systems demand efficient operation of dielectric polymer-based capacitors at high electric fields and elevated temperatures. Here, polyimide (PI) dielectric composites prepared from in situ polymerization in the presence of inorganic nanofillers are reported. The systematic manipulation of the dielectric constant and bandgap of the inorganic fillers, including Al2O3, HfO2, TiO2, and boron nitride nanosheets, reveals the dominant role of the bandgap of the fillers in determining and improving the high-temperature capacitive performance of the polymer composites, which is very different from the design principle of the dielectric polymer composites operating at ambient temperature. The Al2O3- and HfO2-based PI composites with concomitantly large bandgap and moderate dielectric constants exhibit substantial improvement in the breakdown strength, discharged energy density, and charge–discharge efficiency when compared to the state-of-the-art dielectric polymers. The work provides a design paradigm for high-performance dielectric polymer nanocomposites for electrical energy storage at elevated temperatures.

Polymer dielectrics are preferred materials for high-energy-density capacitive energy storage. In particular, high-temperature dielectrics that can withstand harsh conditions, e.g., ≥150 °C, is of crucial importance for advanced electronics and electrical power systems. Herein, high-temperature dielectric polymer composites composed of polyetherimide (PEI) matrix and hafnium oxide (HfO2) nanoparticles are presented. It is found that the incorporation of HfO2 with a moderate dielectric constant and a wide bandgap improves the dielectric constant and simultaneously reduces the high-field leakage current density of the PEI nanocomposites. As a result, the PEI/HfO2 composites exhibit superior energy storage performance to the current high-temperature engineering polymers at elevated temperatures. Specifically, the nanocomposite with 3 vol% HfO2 displays a discharged energy density of 2.82 J/cm3 at 150 °C, which is 77% higher than neat PEI. This work demonstrates the effectiveness of incorporation of the nanofiller with a medium dielectric constant into the polymer on the improvement of high-temperature capacitive properties of the polymer composites.

Rationale

The mammalian target of rapamycin complex 1 inhibitor, rapamycin, has been shown to decrease atherosclerosis, even while increasing plasma low-density lipoprotein levels. This suggests an antiatherogenic effect possibly mediated by the modulation of inflammatory responses in atherosclerotic plaques.

Objective

Our aim was to assess the role of macrophage mammalian target of rapamycin complex 1 in atherogenesis.

Methods and results

We transplanted bone marrow from mice in which a key mammalian target of rapamycin complex 1 adaptor, regulatory-associated protein of mTOR, was deleted in macrophages by Cre/loxP recombination (Mac-Rap(KO) mice) into Ldlr(-/-) mice and then fed them the Western-type diet. Atherosclerotic lesions from Mac-Rap(KO) mice showed decreased infiltration of macrophages, lesion size, and chemokine gene expression compared with control mice. Treatment of macrophages with minimally modified low-density lipoprotein resulted in increased levels of chemokine mRNAs and signal transducer and activator of transcription (STAT) 3 phosphorylation; these effects were reduced in Mac-Rap(KO) macrophages. Although wild-type and Mac-Rap(KO) macrophages showed similar STAT3 phosphorylation on Tyr705, Mac-Rap(KO) macrophages showed decreased STAT3Ser727 phosphorylation in response to minimally modified low-density lipoprotein treatment and decreased Ccl2 promoter binding of STAT3.

Conclusions

The results demonstrate cross-talk between nutritionally induced mammalian target of rapamycin complex 1 signaling and minimally modified low-density lipoprotein-mediated inflammatory signaling via combinatorial phosphorylation of STAT3 in macrophages, leading to increased STAT3 activity on the chemokine (C-C motif) ligand 2 (monocyte chemoattractant protein 1) promoter with proatherogenic consequences.