Ferroptosis is a predominant contributor to graft kidney ischemia‒reperfusion injury (IRI), resulting in delayed graft function (DGF). However, much less is known about the early predicting biomarkers and therapeutic targets of DGF, especially aiming at ferroptosis. Here, we propose a precise predicting model for DGF, relying on the Akirin1 level in extracellular vesicles (EVs) derived from recipient urine 48 h after kidney transplant. In addition, we decipher a new molecular mechanism whereby Akirin1 induces ferroptosis by strengthening TP53-mediated suppression of SLC7A11 during the graft kidney IRI process, that is, Akirin1 activates the EGR1/TP53 axis and inhibits MDM2-mediated TP53 ubiquitination, accordingly upregulating TP53 in two ways. Meanwhile, we present the first evidence that miR-136-5p enriched in EVs secreted by human umbilical cord mesenchymal stem cells (UM-EVs) confers robust protection against ferroptosis and graft kidney IRI by targeted inhibition of Akirin1 but knockout of miR-136-5p in UM sharply mitigates the protection of UM-EVs. The functional and mechanistic regulation of Akirin1 is further corroborated in an allograft kidney transplant model in wild-type and Akirin1-knockout mice. In summary, these findings suggest that Akirin1, which prominently induces ferroptosis, is a pivotal biomarker and target for early diagnosis and treatment of graft kidney IRI and DGF after kidney transplant.

Nanocomposites with polymer matrix provide tremendous opportunities to investigate new functions beyond those of traditional materials. The global community is gradually tending toward the use of composite and nanocomposite materials. This review is aimed at reporting the recent developments and understanding revolving around hybridizing fillers for composite materials. The influence of various analyses, characterizations, and mechanical properties of the hybrid filler are considered. The introduction of hybrid fillers to polymer matrices enhances the macro and micro properties of the composites and nanocomposites resulting from the synergistic interactions between the hybrid fillers and the polymers. In this review, the synergistic impact of using hybrid fillers in the production of developing composite and nanocomposite materials is highlighted. The use of hybrid fillers offers a viable way to improve the mechanical, thermal, and electrical properties of these sophisticated materials. This study explains the many tactics and methodologies used to install hybrid fillers into composite and nanocomposite matrices by conducting a thorough analysis of recent research. Furthermore, the synergistic interactions of several types of fillers, including organic-inorganic, nano-micro, and bio-based fillers, are fully investigated. The performance benefits obtained from the synergistic combination of various fillers are examined, as well as their prospective applications in a variety of disciplines. Furthermore, the difficulties and opportunities related to the use of hybrid fillers are critically reviewed, presenting perspectives on future research paths in this rapidly expanding area of materials science.

In the present paper, composite thin films of barium strontium titanate (BaxSr1-xTiO3) with an acceptor modifier (magnesium oxide-MgO) were deposited on metal substrates (stainless steel type) using the sol-gel method. The composite thin films feature BaxSr1-xTiO3 ferroelectric solid solution as the matrix and MgO linear dielectric as the reinforcement, with MgO concentrations ranging from 1 to 5 mol%. Following thermal treatment at 650 °C, the films were analyzed for their impedance response. Experimental impedance spectra were modeled using the Kohlrausch-Williams-Watts function, revealing stretching parameters (β) in the range of approximately 0.78 to 0.89 and 0.56 to 0.90 for impedance and electric modulus formalisms, respectively. Notably, films modified with 3 mol% MgO exhibited the least stretched relaxation function. Employing the electric equivalent circuit method for data analysis, the \"circle fit\" analysis demonstrated an increase in capacitance from 2.97 × 10-12 F to 5.78 × 10-10 F with the incorporation of 3 mol% MgO into BST-based thin films. Further analysis based on Voigt, Maxwell, and ladder circuits revealed trends in resistance and capacitance components with varying MgO contents, suggesting non-Debye-type relaxation phenomena across all tested samples.

Nowadays, it is well known that on the ship, free space is at a premium. Unfortunately, every part on the ship has its duration before the failure, and the spare parts occupy the space. The broken part must be replaced when the failure occurs to maintain the ship\'s operation. Developing 3D printer technology and particular material technology, it has become possible to print a spare part that can replace broken. However, due to hazardous environments (salt, humidity, vibrations, etc.), printed parts change their properties. Electrical capacity and further dielectric permittivity is a parameter or metric that has to be monitored since it directly influences the printed part material structure. Therefore, this paper aims to research the impact of relative dielectric constant in additive manufacturing on printed ship\'s spare parts since infill patterns and density were changed due to a hazardous environment. The experiment, in which the three shaped material samples are created, consists of the following equipment, the Ultimaker S5 3D printer, Polylactic Acid (PLA) and Acrylonitrile-Butadiene-Styrene (ABS) materials, and LC HM 8018 m. Results show relative dielectric constant changes between 1.7778 and 2.8141 for PLA and between 2.1979 and 2.9989 for ABS, depending on infill density and pattern. ANOVA test for ABS is performed to investigate how the calculated dielectric constant relates to the infill density for various infill shapes. Scores are: F = 154.3773, Fcrit = 5.1432, and p = 6.9269·10-6. ANOVA test for PLA resulted in scores F = 18.911, Fcrit = 5.1432, and p = 0.0022.

Triboelectric nanogenerator (TENG) manifests distinct advantages such as multiple structural selectivity, diverse selection of materials, environmental adaptability, low cost, and remarkable conversion efficiency, which becomes a promising technology for micro-nano energy harvesting and self-powered sensing. Tribo-dielectric materials are the fundamental and core components for high-performance TENGs. In particular, the charge generation, dissipation, storage, migration of the dielectrics, and dynamic equilibrium behaviors determine the overall performance. Herein, a comprehensive summary is presented to elucidate the dielectric charge transport mechanism and tribo-dielectric material modification principle toward high-performance TENGs. The contact electrification and charge transport mechanism of dielectric materials is started first, followed by introducing the basic principle and dielectric materials of TENGs. Subsequently, modification mechanisms and strategies for high-performance tribo-dielectric materials are highlighted regarding physical/chemical, surface/bulk, dielectric coupling, and structure optimization. Furthermore, representative applications of dielectric materials based TENGs as power sources, self-powered sensors are demonstrated. The existing challenges and promising potential opportunities for advanced tribo-dielectric materials are outlined, guiding the design, fabrication, and applications of tribo-dielectric materials.

This paper highlights the use and applications of the energy loss function (ELF) for materials analysis by using electron energy loss spectroscopy (EELS). The basic Drude-Lindhart theory of the ELF is briefly presented along with reference to reflection electron energy loss (REELS) data for several dielectric materials such as insulating high-k binary oxides and semiconductors. Those data and their use are critically discussed. A comparison is made to the available ab initio calculations of the ELF for these materials. Experimental, high-resolution TEM-EELS data on Si, SiC, and CeO2 obtained using a high-resolution, double-Cs-corrected transmission electron microscope are confronted to calculated spectra on the basis of the ELF theory. Values of plasmon energies of these three dielectric materials are quantitatively analyzed on the basis of the simple Drude\'s free electron theory. The effects of heavy ion irradiation on the TEM-EELS spectra of Si and SiC are addressed. In particular, the downward shifts of plasmon peaks induced by radiation damage and the subsequent amorphization of Si and SiC are discussed. TEM-EELS data of CeO2 are also analyzed with respect to the ELF data and with comparison to isostructural ZrO2 and PuO2 by using the same background and with reference to ab initio calculations.

In this work, were synthesized (Pb0.91La0.09)(Zr0.65Ti0.35)0.9775O3 ceramic materials with different concentrations of praseodymium (0, 0.1, 0.3, 0.5, 1 wt.%) via gel-combustion route and sintered by the hot uniaxial pressing method. Measurements were conducted on the obtained ceramics using X-ray powder diffraction (XRD), scanning electron microscope (SEM), EDS analysis, and examination of dielectric and ferroelectric optical properties. Results give us a detailed account of the influences of the praseodymium ions on the structural, microstructural, and dielectric properties. 3D fluorescence maps and excitation and emission spectra measurements show how a small admixture changes the ferroelectric relaxor behavior to an optically active ferroelectric luminophore.

In order to improve the dielectric thermal stability of polyvinylidene fluoride (PVDF)-based film, nano silicon nitride (Si3N4) was introduced, and hence the energy storage performance was improved. The introduction of nano Si3N4 fillers will induce a phase transition of P(VDF-HFP) from polar β to nonpolar α, which leads to the improved energy storage property. As such, the discharging energy density of Si3N4/P(VDF-HFP) composite films increased with the amount of doped Si3N4. After incorporating 10wt% Si3N4 in Si3N4/P(VDF-HFP) films, the discharging density increased to 1.2 J/cm3 under a relatively low electric field of 100 MV/m. Compared with a pure P(VDF-HFP) film, both the discharging energy density and thermal dielectric relaxor temperature of Si3N4/P(VDF-HFP) increased. The working temperature increased from 80 °C to 120 °C, which is significant for ensuring its adaptability in high-temperature energy storage areas. Thus, this result indicates that Si3N4 is a key filler that can improve the thermal stability of PVDF-based energy storage polymer films and may provide a reference for high-temperature capacitor materials.

A high configurational entropy, achieved through a proper design of compositions, can minimize the Gibbs free energy and stabilize the quasi-equilibrium phases in a solid-solution form. This leads to the development of high-entropy materials with unique structural characteristics and excellent performance, which otherwise could not be achieved through conventional pathways. This work develops a high-entropy nonlinear dielectric system, based on the expansion of lead magnesium niobate-lead titanate. A dense and uniform distribution of nano-polar regions is observed in the samples owing to the addition of Ba, Hf, and Zr ions, which lead to enhanced performance of nonlinear dielectrics. The fact that no structural phase transformation is detected up to 250 °C, and no noticeable change or a steep drop in structural and electrical characteristics is observed at high temperatures suggests a robust thermal stability of the dielectric systems developed. With these advantages, these materials hold vast potential for applications such as dielectric energy storage, dielectric tunability, and electrocaloric effect. Thus, this work offers a new high-entropy configuration with elemental modulation, with enhanced dielectric material features.

The ever increasing demand for high-speed communication at high frequency promotes the rapid development of low-dielectric polymer films. Aromatic polyimide (PI) has been widely used as the main dielectrics in the flexible circuit board due to its excellent dielectric, mechanical, and thermal properties. Nevertheless, the dielectric constant of PI films at a high frequency range (several GHz) is relatively high and cannot satisfy the requirement of high-frequency communication. On this basis, a hyper-crosslinked polymer (HCP) and fabricated all-organic HCP/PI composite films through a physical blending method is synthesized. The porous structure of HCP is helpful to reduce the dielectric constant of PI matrix. The effects of HCP loadings on the dielectric, mechanical, and thermal properties of HCP/PI composite films are systematically investigated. The dielectric constants of the composite films can be reduced to 1.6-1.8 in the frequency range of 8.2-9.6 GHz when the HCP content reached 10 wt.%. The proposed method in this work is simple and effective to reduce the dielectric constant of PI and can be easily extended to other organic component-filled PI systems.