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A series of Sr4.5Ca0.5MTi3Nb7O30 [M = La0.5Nd0.5 (LN), La1/3Nd1/3Sm1/3 (LNS) and La0.25Nd0.25Sm0.25Eu0.25 (LNSE)] ceramics with different A-site configuration entropy were prepared, and the effects of the A-site configuration entropy on the dielectric and ferroelectric properties were investigated. Due to the combined effect of high entropy and solid solution, the best dielectric performance was achieved in the LNS composition, where the dielectric constant remained around 650 in the temperature range of 269–515 K with a change rate of less than 15%. Under the DC high voltage field up to 67 kV/cm, each component's polarization characteristics and dielectric constants obtained good electric field stability and temperature stability under a high electric field. [ABSTRACT FROM AUTHOR]

The effects of La/Ho co-substitution on multiferroic characteristics were investigated for BiFeO3 ceramics together with structure evolution. The symmetry in Bi1−x(La0.65Ho0.35)xFeO3 ceramics changed from R3c to Pna21 and finally Pbnm with increasing x. Ferroelectricity was significantly improved with La/Ho co-substitution, and Pr reached the maximum of 30.9 μC/cm2 at 160 kV/cm at x = 0.16, where the R3c/Pna21 morphotropic phase boundary was determined. The weak ferromagnetism was released as the symmetry changed from R3c to Pna21, and subsequently the saturated M–H loop could be determined gradually with increasing x, and Mr increased continuously. The electric field-controlled magnetism could be characterized by the significant magnetism variation due to the electric field-induced transition of Pna21/R3c, which occurred during the poling process, and this transition became reversible by the help of annealing after poling. Compared with the situation of Bi1−xNdxFeO3 (the ion radius is the same as the effective one of La0.65Ho0.35), the present co-substituted BiFeO3 ceramics exhibited superior electric field-induced transition of Pna21/R3c with a maximum change rate of 47.03% in remanent magnetization under an electric field, which enhanced the magnetoelectric effect. [ABSTRACT FROM AUTHOR]

A-site high entropy Ba4(La0.2Nd0.2Sm0.2Eu0.2Y0.2)2Ti4Nb6O30 tungsten bronze ceramics were designed and prepared by a standard solid state sintering process. First-order ferroelectric transition occurs around 240 °C on heating, while around 136 °C on cooling. Pinched and asymmetric P–E hysteresis loops were observed within and below the thermal hysteresis temperature range of the ferroelectric transition. Pinched P–E hysteresis loops were attributed to the coupling between the ferroelectric transition and the commensurate/incommensurate modulation transition. The reason for the asymmetry of the hysteresis loop was the presence of an internal bias electric field. Different measuring procedures were designed to clarify the evolution of hysteresis loop asymmetry. The existence of oxygen vacancy and Eu3+/Eu2+ was identified by x-ray photoemission spectroscopy. The electric field cycling with elevated temperatures caused defect dipoles incline to align along the direction of spontaneous polarization leading to the internal bias electric field. Due to the A-site high entropy effect, dielectric strength of Ba4(La0.2Nd0.2Sm0.2Eu0.2Y0.2)2Ti4Nb6O30 ceramics is up to 300 kV/cm, which is increased by more than 50% than that with the single element in the A1-site. [ABSTRACT FROM AUTHOR]

The West Kunlun Orogenic Belt (WKOB) in the northwestern Tibetan Plateau records key information about the tectonic evolution of the Proto-Tethys Ocean. To further constrain the Early Palaeozoic tectonic evolution of the WKOB, we report petrography, geochronology, whole-rock geochemistry, and Sr-Nd-Hf-O isotope data of the newly identified Ordovician Nanpingxueshan gabbros in the southern WKOB. Laser ablation-inductively coupled plasma-mass spectroscopy (LA-MC-ICP-MS) U-Pb zircon dating reveals that the gabbroic intrusion was emplaced during 476–471 Ma. Geochemically, the gabbroic rocks exhibit a tholeiitic signature and can be subdivided into two groups, i.e. normal arc-like gabbros (AGs) and Nb-enriched gabbros (NEGs). The AGs have TiO2 (1.20–1.64%), P2O5 (0.18–0.25%), and Nb (4.60–7.64 ppm) contents, fractionated REE patterns ((La/Yb)N = 2.64–4.11), and Nb-Ta depletion (Nb/La = 0.37–0.50). Compared with AGs, the NEGs have higher TiO2 (1.74–2.68%), P2O5 (0.34–0.55%), and Nb (10.79–14.08 ppm) contents and Nb/La ratios of 0.45–0.53, which are similar to typical Nb-enriched arc basalts. Isotopically, the AGs have depleted whole-rock εNd(t) values of 3.22 to 4.04 and negative to positive zircon εHf(t) values of −1.8 to 7.8, while the NEGs exhibit slightly lower whole-rock εNd(t) values of 0.69 to 3.18, zircon εHf(t) values of −7.8 to 4.6, and mostly δ18O values greater than those of normal mantle zircon. Integrated analyses reveal that the AGs and NEGs can be attributed to a similar mantle source metasomatized by different proportions of subducted sediment-derived melt during the subduction process. Our new data, combined with the results of previous studies, suggest that the southward subduction of the Proto-Tethys Ocean under the WKOB initiated at ca. 530 Ma. The long-term southward subduction led to the formation of the massive Early Palaeozoic accretionary complex in the South Kunlun Terrane, while trench retreat led to migration of the arc magmatism northward from the Mazar – Tianshuihai Terrane to the South Kunlun Terrane, as well as back-arc extension in the Mazar – Tianshuihai Terrane. [ABSTRACT FROM AUTHOR]

BACKGROUND: The insect cuticle consists of chitin fibers and a protein matrix, which plays an important role in protecting the body from invasion of various pathogens and prevents water loss. Periodic synthesis and degradation of the cuticle is required for the growth and development of insects. Key genes involved in cuticle formation have long been considered a potential target for pest control. RESULTS: In this study, a member of the RR‐2 subfamily of cuticular protein 8 (DcCP8) was identified from the Diaphorina citri genome database. Immunofluorescence analysis suggested that DcCP8 was mainly located in the Diaphorina citri exocuticle and can be induced to up‐regulate 12 h following 20‐hydroxyecdysone (20E) treatment. Silencing of DcCP8 by RNA interference (RNAi) significantly disrupted the metamorphosis to the adult stage, and improved the permeability of the cuticle. Transmission electron microscopy (TEM) analysis revealed that the synthesis of the exocuticle was impressed after silencing of DcCP8. Furthermore, the recombinant DcCP8 protein exhibited chitin‐binding properties in vitro, down‐regulation of DcCP8 significantly inhibited expression levels of chitin metabolism‐related genes. Additionally, a sprayable RNAi method targeting DcCP8 based on star polycation (SPc) nanoparticles‐wrapped double‐stranded RNA (dsRNA) significantly increased Diaphorina citri mortality. Transcriptome sequencing further confirmed that genes associated with the endocytic pathway and immune response were up‐regulated in Diaphorina citri after SPc treatment. CONCLUSIONS: The current study indicated that DcCP8 is critical for the formation of Diaphorina citri exocuticles, and lays a foundation for Diaphorina citri control based on large‐scale dsRNA nanoparticles. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Numerous hybrid improper ferroelectrics have been discovered in bulk oxides with layered perovskite structures. In contrast, the competition between the interlayer rumpling and oxygen octahedral rotation suppresses the ferroelectricity in layered perovskite material with trivalent cation at the B-site. In the present work, single-phase dense La2Sr(Sc1−xFex)2O7 ceramics with double-layered Ruddlesden–Popper structures have been prepared, and room-temperature ferroelectricity is discovered in the ceramics with x ≤ 0.10. The ferroelectric polarization and coercive field decrease with increasing content of Fe3+ cations, consistent with the decline of oxygen octahedral rotation and tilting angles. Although the linear relationship between the Curie temperature and the tolerance factor for La2Sr(Sc1−xFex)2O7 ceramics is established, the line is far away from that for A2+3B4+2O7 ceramics due to the large interlayer rumpling in the present ceramics. Although no single-phase multiferroic has been discovered in this work, an effective way to introduce magnetism into hybrid improper ferroelectric is provided. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether macrophage-derived exosomal mir-222 regulates Caspase-10 and whether macrophage-derived exosomes promote glioma proliferation by targeting Caspase-10 through mir-222. Methods: Macrophages were transfected with mir-222 mimics, and then macrophage-derived exosomes carrying mir-222 were transfected into glioma cells. Caspase-10 overexpression vector was constructed on this basis. RT-PCR was used to detect mir-222 expression in macrophages and glioma cells. CCK-8 assay was used to detect the proliferative activity of glioma cells. Dual-luciferase reporter assay was used to verify the targeting binding of mir-222 with Caspase-10 gene. Western blot was used to detect Caspase-10 expression. Results: Transmission electron microscopy showed that macrophagederived exosomes had spherical structures with a diameter of about 100 nm; mir-222 mimic significantly promoted the expression of mir-222 in macrophages; macrophage-derived exosomal mir-222 increased mir-222 expression and promoted proliferation in glioma cells; mir-222 could target bind with Caspase-10; mir-222 mimic significantly inhibited Caspase-10 expression. Conclusion: Macrohpage-derived exosomal mir-222 plays an important role in promoting glioma proliferation by downregulating Caspase-10 expression through targeted binding. [ABSTRACT FROM AUTHOR]