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Electrostrictive materials have wide applications in modern high‐precision electronic devices. Driven by growing environmental concerns, there is demand for lead‐free materials with superior electrostriction behaviors. In this study, we demonstrate a record‐high electrostrictive coefficient of ~0.0712 m4 C−2 in perovskite ferroelectric ceramics, along with hysteresis‐free strain as well as excellent frequency and thermal stabilities, in lead‐free BaTiO3‐based ceramics through a polarization nanocluster design. By appropriately introducing Li+ and Bi3+ into the BaTiO3 lattice matrix, the long‐range ferroelectric ordering can be broken, and polarization nanoclusters can be formed, resulting in a relaxor state with concurrently suppressed polarization and maintained electro‐strain. A three‐dimensional atomic model constructed using advanced neutron total‐scattering data combined with the reverse Monte Carlo method indicates the existence of Bi and Li segregations at the subnanometer scale, which confirms the prediction made by density functional theory calculations. Such a short‐range chemical order destroys the long‐range ferroelectric order of the off‐centered Ti polar displacements and leads to the embedding of Li+/Bi3+‐rich polar nanoregions in the Ba2+‐rich polarization disorder matrix. Further, a completely reversible electric‐field‐induced lattice strain is observed, giving rise to pure electrostriction without hysteresis behavior. This work provides a novel strategy for developing lead‐free relaxor ferroelectrics with high electrostriction performance. [ABSTRACT FROM AUTHOR]

Highly active and multifunctional non‐precious metal‐based hydrogen evolution reaction (HER) eletcrocatalysts have aroused great interest in the large‐scale conversion of sustainable electrical energy to fuels and feedstocks in different application scenarios. Here, a metal sulfide‐based super hybrid nanoarray composed of a metallic Co3S4 nanosheet, P doped WS2 nanosheet, and Co9S8 nanoparticles (Super‐Co3S4/P‐WS2/Co9S8) for all‐pH HER is reported. The Super‐Co3S4/P‐WS2/Co9S8 only requires 58, 70, and 129 mV in alkaline, acid, and neutral media, respectively, to reach 10 mA cm‐2, which also presents fast reaction kinetics and high long‐term stability. The experimental and density functional theory (DFT) results verify that the abundant active heterostructure in Super‐Co3S4/P‐WS2/Co9S8 can not only provide Pt‐like H*‐adsorption Gibbs free energy (ΔGH*) but also promote the H2O adsorption and dissociation kinetics for all‐pH HER. Moreover, the collaboration of favorable metallic components and special nanoarray morphology can also strengthen the electric conductivity for electron transfer and promote the maximum exposure of active heterointerfaces for mass transport in electrocatalysis. The interesting strategy herein is expected to inspire the future design of advanced metal sulfide‐based heterostructures for energy storage and conversion. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Previous work from our laboratory has demonstrated in vivo persistence of CD103+CD69+ brain resident memory CD8+ T‐cells (bTRM) following viral infection, and that the PD‐1: PD‐L1 pathway promotes development of these TRM cells within the brain. Although glial cells express low basal levels of PD‐L1, its expression is upregulated upon IFN‐γ‐treatment, and they have been shown to modulate antiviral T‐cell effector responses through the PD‐1: PD‐L1 pathway. Methods: We performed flow cytometric analysis of cells from co‐cultures of mixed glia and CD8+ T‐cells obtained from wild type mice to investigate the role of glial cells in the development of bTRM. Results: In this study, we show that interactions between reactive glia and anti‐CD3 Ab‐stimulated CD8+ T‐cells promote development of CD103+CD69+ CD8+ T‐cells through engagement of the PD‐1: PD‐L1 pathway. These studies used co‐cultures of primary murine glial cells obtained from WT animals along with CD8+ T‐cells obtained from either WT or PD‐1 KO mice. We found that αCD3 Ab‐stimulated CD8+ T‐cells from WT animals increased expression of CD103 and CD69 when co‐cultured with primary murine glial cells. In contrast, significantly reduced expression of CD103 and CD69 was observed using CD8+ T‐cells from PD‐1 KO mice. We also observed that reactive glia promoted high levels of CD127, a marker of memory precursor effector cells (MPEC), on CD69+ CD8+ T‐cells, which promotes development of TRM cells. Interestingly, results obtained using T‐cells from PD‐1 KO animals showed significantly reduced expression of CD127 on CD69+ CD8+ cells. Additionally, blocking of glial PD‐L1 resulted in decreased expression of CD103, along with reduced CD127 on CD69+ CD8+ T‐cells. Conclusions: Taken together, these results demonstrate a role for activated glia in promoting development of bTRM through the PD‐1: PD‐L1 pathway. [ABSTRACT FROM AUTHOR]

Objectives miR-375 is one of the highly expressed micro RNAs (mi RNAs) found in pancreatic islets of both humans and mice. In this study, we investigated functions of mi RNA miR-375 in porcine pancreatic stem cells ( PSC). Materials and methods We transfected mimic and inhibitor of miR-375 in PSCs to measure functional roles of the micro RNA and its effects on cell cycle proliferation and cell differentiation were determined. Luciferase assays were also performed to reveal the target gene of miR-375. Results Overexpression of miR-375 suppressed proliferation, promoted apoptosis and inhibited differentiation into islet-like cells. PDK1 was identified as being a target of miR-375. Furthermore, we found that overexpression of miR-375 inhibited activation of the PDK1- AKT signalling pathway. Conclusion miR-375 directly targeted PDK1 in porcine PSCs, suppressing cell proliferation and differentiation into islet-like cells. [ABSTRACT FROM AUTHOR]

Objectives Porcine pancreatic stem cells ( PSCs) are highly valuable in transplantation applications for type II diabetes. However, there are still many problems to be solved before they can be used in the clinic, such as insufficient cell number availability and low secretion level of insulin. It has been reported that Wnt3a plays pivotal roles during cell proliferation and differentiation. Here, we have aimed to establish an ideal research platform using the T- REx™ system, to study mechanisms of Wnt3a during PSC proliferation and differentiation. Materials and methods Construction of the recombinant plasmid and cell transfection were used for establishment of a porcine PSC line. Related gene expressions were examined using quantitative real-time PCR ( QRT- PCR), western blotting, immunostaining and flow cytometry. BrdU incorporation assay and cell cycle analysis were used to investigate Wnt3a roles in PSCs. Results Wnt3a-expressing clones regulated by T- REx™ were successfully obtained. Wnt3a and GFP expression were strictly regulated by Dox in a time- and dose-dependent manner. Furthermore, we found that Wnt3a-expressing porcine PSCs induced by Dox exhibited raised proliferative potential. After Dox stimulation, expression of PCNA, C- MYC and active β-catenin were higher, but were down-regulated after Dkk1 addition. Conclusion We established a porcine PSC line that dynamically expressed Wnt3a, and we found that Wnt3a promoted PSC proliferative potential. This inducible expression system thus provides an important tool for further study on porcine PSC development and differentiation. [ABSTRACT FROM AUTHOR]

Long-term neurological sequela is common among herpes simplex encephalitis (HSE) survivors. Animal models for HSE are used to investigate mechanisms of acute disease, but little has been done to model chronic manifestations of HSE. The current study presents a detailed, systematic analysis of chronic neuropathology, including characterization of topography and sequential progression of degenerative lesions and inflammation. Subsequent to intranasal HSV-1 infection, inflammatory responses that were temporally and spatially distinct persisted in infected cortical and brain stem regions. Neutrophils were present exclusively within the olfactory bulb and brain stem regions during the acute phase of infection, while the chronic inflammation was marked by plasma cells, lymphocytes and activated microglia. The chronic lymphocytic infiltrate, cytokine production, and activated microglia were associated with the loss of cortical neuropile in the entorhinal cortex and hippocampus. Animals surviving the acute infection showed a spectrum of chronic lesions from decreased brain volume, neuronal loss, activated astrocytes, and glial scar formation to severe atrophy and cavitations of the cortex. These lesions were also associated with severe spatial memory deficits in surviving animals. Taken together, this model can be utilized to further investigate the mechanisms of neurological defects that follow in the wake of HSE. [ABSTRACT FROM AUTHOR]

The crystal structures of BiOI under different pressures are predicted, in which the phase transformation from tetragonal BiOI into orthorhombic BiOI is observed at 100 GPa due to the appearance of Bi–I bonds (Bi‐6s2 lone pair and I‐pz obital) between interlayer Bi and I atoms. Most interestingly, for orthorhombic BiOI, an isostructural electronic phase separation is observed at 160 GPa. The electronic structure of BiOI separates into semiconductor state (contributed by intralayer O–Bi–O) and metal state, which originate from the interlayer I–I bonds. More specifically, conversion from interlayer Bi–I interaction to interlayer I–I interaction under higher pressure, results in the continuous decline of the I‐dx2–y2 energy band, which then crosses the Fermi‐level. In comparison, the O–Bi–O layer shows almost no change, owing to its strong covalent bonds. These results demonstrate that the dramatic variation of the interaction between the van der Waals layers can lead to the metallic iodine character in BiOI. [ABSTRACT FROM AUTHOR]