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BiFeO3–BaTiO3 (BF–BT) is one of the lead-free piezoceramic materials with high Curie temperature (TC) and high polarization. Herein, the (Bi0.5Li0.5Ti)6+ group elements are introduced into the 0.75BiFeO3−0.25BaTiO3 (0.75BF–0.25BT) system to optimize comprehensive performances via optimizing the intrinsic piezoelectric contribution and the extrinsic piezoelectric contribution. For intrinsic piezoelectric contribution, the tetragonal phase ratio of the ceramics is increased. For extrinsic piezoelectric contribution, the grain structures and the domain structures of the ceramics are improved with a relaxor state in which small-sized domains and large-sized domains coexist. The best overall performances are obtained at x = 0.010 with piezoelectric constant d33 ∼ 130 pC/N at room temperature, d33 ∼ 231 pC/N at 313 °C, resistance ρ ∼ 1.49 × 106 Ω cm at 300 °C, and Curie temperature TC ∼ 632 °C that improved significantly. Moreover, when x = 0.010, the piezoelectric thermal stability is also significantly improved, with Δd33 being less than 15% before 200 °C and maintaining 60% of d33 at 400 °C. The present experiments provide a new strategy to investigate the origin of the enhanced piezoelectric response of BF–BT ceramics as well as their applications in the field of high-temperature lead-free piezoelectricity. [ABSTRACT FROM AUTHOR]

Novel antimicrobial strategies are urgently needed to treat extensively drug‐resistant (XDR) bacterial infections due to the high mortality rate and lack of effective therapeutic agents. Herein, nanoengineered human umbilical cord mesenchymal stem cells (hUC‐MSCs), named PMZMU, are designed as a sonosensitizer for synergistic sonodynamic‐nano‐antimicrobial therapy against gram‐negative XDR bacteria. PMZMU is composed of a bacterial targeting peptide (UBI29‐41) modified hUC‐MSCs membrane (MSCm), a sonosensitizer meso‐tetra(4‐car‐boxyphenyl) porphine doped mesoporous organo‐silica nanoparticle and an acidity‐responsive metal–organic framework ZIF‐8. This innovative formulation enables efficient loading of polymyxin B, reduces off‐target drug release, increases circulation and targeting efficacy, and generates reactive oxygen species upon ultrasound irradiation. PMZMU exhibits remarkable in vitro inhibitory activity against four XDR bacteria: Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa (PA), and Escherichia coli. Taking advantage of the bacterial targeting ability of UBI29‐41 and the inflammatory chemotaxis of hUC‐MSC, PMZMU can be precisely delivered to lung infection sites thereby augmenting polymyxin B concentration. PMZMU‐mediated sonodynamic therapy significantly reduces bacterial burden, relieves inflammatory damage by promoting the polarization of macrophages toward M2 phenotype, and improves survival rates without introducing adverse events. Overall, this study offers promising strategies for treating deep‐tissue XDR bacterial infections, and guides the design and optimization of biomimetic nanomedicine. [ABSTRACT FROM AUTHOR]

The performance of potassium sodium niobate ((K, Na) NbO3, KNN)-based lead-free piezoelectric ceramics has significantly improved over the past decade. However, the performance bottlenecks of KNN-based ceramics cannot be ignored. Here, the Nb2O5 precursor is obtained after thermal pretreatment, which can evidently improve the piezoelectric properties and strain temperature stability of KNN-based ceramics. With the help of the Nb2O5 precursor treated at 800 °C, the optimal piezoelectric constant d33 of 303 pC/N, inverse piezoelectric constant d * 33 of 378 pm/V, Curie temperature TC of 310 °C and electromechanical coupling factor kp of 42% are obtained, and the value of d33 improves by about 30% compared with that of the ceramic prepared with untreated Nb2O5 as raw material. Additionally, in comparison with the strain temperature stability of the ceramics prepared with untreated Nb2O5 as raw material, the temperature stability is enhanced. Therefore, this study provides a useful approach to break the existing performance bottleneck and further improve the properties of KNN-based ceramics. [ABSTRACT FROM AUTHOR]

We demonstrate a novel concept of domain engineering to simultaneously achieve outstanding piezoelectricity (d33 ∼ 191 pC N−1) and high Curie temperature (TC ∼ 485 °C) in BF ceramics by adding elements with high valence difference. It is revealed that the NaTaO3 additive contributes to tuning the relaxor characteristics and the configuration of macrodomains and nanodomains in the nonergodic state (0.725-x)Bi1.05FeO3–0.275BaTiO3-xNaTaO3–0.3% MnO2, leading to heterogeneous domain structures with rhombohedral-tetragonal phase coexistence. In addition, temperature-dependent piezoelectric characterization studies exhibit a continually increasing d33 with the increase of temperature in this system, and an ultrahigh piezoelectric constant (d33 = 516 pC N−1) can be found at the composition of x = 0.008 when the temperature reaches 320 °C. Combined with in situ XRD and first-principles calculations, we confirm that the enhancements of d33 and Pr in the BF–BT ceramics during the heating process have an intrinsic contribution from the phase transition of R3c to R3m. This work not only provides a concept to obtain ceramics with both excellent piezoelectricity and Curie temperature but also helps understanding the intrinsic origin of unusual high-temperature d33 in BF–BT-based materials, which is useful for further developing BF-based piezoelectric materials. [ABSTRACT FROM AUTHOR]

Abstract: The 0.968[(K0.48Na0.52)]Nb0.95+xSb0.05O3–0.032(Bi0.5Na0.5)ZrO3 [KNNxS–BNZ] lead‐free ceramics with nonstoichiometric niobium ion were fabricated via conventional solid‐state sintering technique and their piezoelectric, dielectric and ferroelectric properties were investigated. When x = 0.010, enhanced piezoelectric properties (d33 ≈ 421 pC/N and kp ≈ 0.47) were obtained due to the construction of rhombohendral—tetragonal phase boundary near room temperature. The KNNxS–BNZ ceramics possesses enhanced Curie temperature (Tc) with improved piezoelectric constant. A large d33 of ~421 pC/N and a high Tc ~256°C can be simultaneously induced in the ceramics with x = 0.010. Especially, good thermal stability was observed in a broad temperature range. The results indicated that our work could benefit development of KNN‐based ceramics and widen their application range. [ABSTRACT FROM AUTHOR]

Nondegenerate optical parametric oscillator (NOPO) above threshold is a simple set-up to generate entangled beams. To more accurately calculate the entanglement between the generated twin beams from the NOPO, we use the Langevin equations for the NOPO with a higher-transmissivity cavity mirror. The obtained new expressions for the amplitude-difference and phase-sum noise spectra suggest that increasing the transmissivity of the output mirror can enhance the entanglement beyond the previous expectation. [ABSTRACT FROM AUTHOR]

Bacterial infections cause high morbidity and mortality worldwide, and the emergence of drug-resistant bacteria further complicates the treatment of infections. Therefore, it is necessary to continuously develop new treatment methods. Polymyxin B (PMB), as the last line of defense, can combat most aerobic Gram-negative bacilli including common drug-resistant bacteria in clinical practice. However, the suboptimal lung tissue concentration of PMB and dose-dependent nephrotoxicity and neurotoxicity limit its clinical application. The nanodrug delivery system offers several key advantages, including high drug loading capacity, excellent biocompatibility, controlled release mechanisms, and targeted delivery. These features enhance the bioavailability of drugs while simultaneously reducing their toxicity and minimizing side effects. In this study, we designed a targeted nanodrug delivery system (PMB@HMnO 2 @NM) consisting of hollow mesoporous manganese dioxide (HMnO 2 ) coated with neutrophil membrane (NM). In a mouse model of acute pneumonia induced by multidrug-resistant Pseudomonas aeruginosa , treatment with PMB@HMnO 2 @NM demonstrated the ability to target bacterial aggregation and specifically deliver the drug to the infected lung tissue. This targeted approach resulted in improved survival rates and reduced inflammatory damage without causing adverse effects. The findings of this study suggest the potential for developing a new class of multifunctional nanodrugs, providing new therapeutic strategies for multidrug-resistant (MDR) bacterial infections. Furthermore, these results provide a solid foundation for the design of biomimetic nanosized antibacterial drugs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

An easy approach is suggested to obtain excellent piezoelectric performances in potassium sodium niobate (KNN)-based ceramics simultaneously with low dielectric loss (tanδ), high Curie temperature ( T C ), and electromechanical coupling factor ( k p ). Herein, a KNN-based ceramics system with nonstoichiometric Nb 5+ is designed. Excessive Nb 5+ occupying the B-site significantly influences the microstructural features and electrical properties of KNN-based ceramics. Furthermore, the excessive Nb 5+ improves the temperature stability of ceramics by providing the domain wall pegging effect and defect dipole. A high T C = 300 °C, large k p = 0.516, and d 33 = 450 pC/N can be simultaneously obtained in the KNN-based ceramics with nonstoichiometric Nb 5+ . These results confirm that the comprehensive electrical properties of KNN-based ceramics can be tuned by optimizing the content of nonstoichiometric Nb 5+ .