Utilization of Nonstoichiometric Nb5+ to Optimize Comprehensive Electrical Properties of KNN-Based Ceramics.

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 (TC), and electromechanical coupling factor (kp). Herein, a KNN-based ceramics system with nonstoichiometric Nb5+ is designed. Excessive Nb5+ occupying the B-site significantly influences the microstructural features and electrical properties of KNN-based ceramics. Furthermore, the excessive Nb5+ improves the temperature stability of ceramics by providing the domain wall pegging effect and defect dipole. A high TC = 300 °C, large kp = 0.516, and d33 = 450 pC/N can be simultaneously obtained in the KNN-based ceramics with nonstoichiometric Nb5+. These results confirm that the comprehensive electrical properties of KNN-based ceramics can be tuned by optimizing the content of nonstoichiometric Nb5+.

Bloodstream infection and pneumonia caused by Chlamydia abortus infection in China: a case report.

BACKGROUND: Chlamydia abortus is generally considered to cause abortion, stillbirth, and gestational sepsis in pregnant women, but it's rare in bloodstream infection and pneumonia. CASE PRESENTATION: We present details of a patient with bloodstream infection and pneumonia caused by Chlamydia abortus. Both blood next-generation sequencing (NGS) and sputum NGS indicate Chlamydia abortus infection. The patient received intravenous infusion of piperacillin sodium and tazobactam sodium (4.5 g/8 h) and moxifloxacin (0.4 g/d) and oral oseltamivir (75 mg/day). Within one month of follow-up, the patient's clinical symptoms were significantly improved, and all laboratory parameters showed no marked abnormality. However, chest computer tomography (CT) showed the inflammation wasn't completely absorbed. And we are still following up. CONCLUSIONS: Chlamydia abortus can cause pneumonia in humans. NGS has the particular advantage of quickly and accurately identifying the infection of such rare pathogens. Pneumonia is generally not life-threatening, and has a good prognosis with appropriate treatment. However, Chlamydia infection can lead to serious visceral complications which clinicians should pay attention to.

Biomimetic Metal-Organic Framework Gated Nanoplatform for Sonodynamic Therapy against Extensively Drug Resistant Bacterial Lung Infection.

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.

Nucleus-Targeting Manganese Dioxide Nanoparticles Coated with the Human Umbilical Cord Mesenchymal Stem Cell Membrane for Cancer Cell Therapy.

Recently, development of drug delivery systems for accurate delivery of antitumor drugs to tumor sites to improve their antitumor efficacy has attracted great interest in the area of cancer immunotherapy. In this report, an intelligent biodegradable hollow manganese dioxide (HMnO2) nanoparticle (NP) with a human umbilical cord mesenchymal stem cell (hUC-MSC) membrane coating was designed to exert efficient chemo-immunotherapy for cancer treatment. A TAT peptide-modified membrane structure was constructed for nuclear targeting. Our findings showed that this new nanoreactor inherited the active targeting capability of MSCs and exhibited tumoritropic accumulation significantly at the cancerous parts. Compared with other formulations, intravenous injection of the NPs markedly inhibited tumor growth, relapse, and metastasis. Moreover, we found that the NPs effectively boosted dendritic cell maturation and recruited effector T cells into tumors. Overall, this work demonstrates the great potential of applying MSC membrane-coated manganese dioxide NPs as nucleus-targeting nanocarriers in cancer chemo-immunotherapy.

Clinical values of metagenomic next-generation sequencing in patients with severe pneumonia: a systematic review and meta-analysis.

Background: Clinical values of metagenomic next-generation sequencing (mNGS) in patients with severe pneumonia remain controversial. Therefore, we conduct this meta-analysis to evaluate the diagnostic performance of mNGS for pathogen detection and its role in the prognosis of severe pneumonia. Methods: We systematically searched the literature published in PubMed, Embase, Cochrane Library, Web of Science, Clinical Trials.gov, CNKI, Wanfang Data, and CBM from the inception to the 28th September 2022. Relevant trials comparing mNGS with conventional methods applied to patients with severe pneumonia were included. The primary outcomes of this study were the pathogen-positive rate, the 28-day mortality, and the 90-day mortality; secondary outcomes included the duration of mechanical ventilation, the length of hospital stay, and the length of stay in the ICU. Results: Totally, 24 publications with 3220 patients met the inclusion criteria and were enrolled in this study. Compared with conventional methods (45.78%, 705/1540), mNGS (80.48%, 1233/1532) significantly increased the positive rate of pathogen detection [OR = 6.81, 95% CI (4.59, 10.11, P < 0.001]. The pooled 28-day and 90-day mortality in mNGS group were 15.08% (38/252) and 22.36% (36/161), respectively, which were significantly lower than those in conventional methods group 33.05% (117/354) [OR = 0.35, 95% CI (0.23, 0.55), P < 0.001, I2 = 0%] and 43.43%(109/251) [OR = 0.34, 95% CI (0.21, 0.54), P < 0.001]. Meanwhile, adjusted treatment based on the results of mNGS shortened the length of hospital stay [MD = -2.76, 95% CI (- 3.56, - 1.96), P < 0.001] and the length of stay in ICU [MD = -4.11, 95% CI (- 5.35, - 2.87), P < 0.001]. Conclusion: The pathogen detection positive rate of mNGS was much higher than that of conventional methods. Adjusted treatment based on mNGS results can reduce the 28-day and 90-day mortality of patients with severe pneumonia, and shorten the length of hospital and ICU stay. Therefore, mNGS advised to be applied to severe pneumonia patients as early as possible in addition to conventional methods to improve the prognosis and reduce the length of hospital stay.

Hardening Effect in Lead-Free KNN-Based Piezoelectric Ceramics with CuO Doping.

As the most promising lead-free piezoelectric ceramics to replace lead zirconate titanate (PZT) ceramics, potassium sodium niobate (KNN) ceramics have been widely studied for their application prospects in various electronic devices. Increasing Qm while maintaining a high piezoelectric activity is quite important for piezoelectric ceramics applied in ultrasonic devices. A KNN-based ceramic with high d33 and Qm is prepared by a conventional solid-state technique to construct polycrystalline phase boundaries and induce defect dipoles. The best overall performance can reach d33 = 260 pC/N, Qm = 210, and TC = 293 °C. The temperature dependence of the relevant parameters is tested, where Qm increases but d33 decreases with the rise of temperature accompanied by escaping ferroelectric boundary, which shows that the polarization rotation plays an important role in the two parameters. The hardening effect of KNN-based ceramics with CuO doping is further studied by first-principles calculations, demonstrating that the Cu doping strongly disturbs the ferroelectric order, but the formation of defect dipoles could stabilize the ferroelectric order. It is illustrated that defect dipoles always find their ground state at the site near the domain walls and the oriented defect dipoles hinder the polarization rotation severely, confirming the role of the defect dipoles in KNN-based materials.

Simultaneous Enhancement of Energy Storage and Hardness Performances in (Na0.5Bi0.5)0.7Sr0.3TiO3-Based Relaxor Ferroelectrics Via Multiscale Regulation.

For (Na0.5Bi0.5)0.7Sr0.3TiO3-based (BNST) energy storage materials, a critical bottleneck is the early polarization saturation and low breakdown electric field (Eb), which severely limits further development in the field of advancing pulsed power capacitors. Herein, a strategy, via multiscale regulation, including synergistically manipulation of the domain configuration and microstructure evolution in BNST-based ceramics, is propounded through introducing LiTaO3(LT). The composition-driven fine domain size, as demonstrated by macroscale (size effect and dielectric response) and mesoscale (domains relaxor behavior) analysis, provides robust evidence of delayed polarization saturation and large polarization difference. Theoretical simulations and experimental results confirm that the fine grain size, uniform grain size distribution, and insignificant secondary phase contribute to the enhancements of Eb. Further analyses of the intrinsic electronic structure reveal the intrinsic mechanism for enhancing Eb via first-principles calculations on the basis of density functional theory. Consequently, owing to improved Eb, delayed polarization saturation, and refined grain size, excellent comprehensive performances [high Wrec of 5.52 J/cm3, large η of 85.68%, high hardness H of 7.06 GPa, and broad operating temperature range (20-140 °C)] are realized. We believe that these findings can provide a thorough understanding of the origins of excellent comprehensive performances in BNST-based ceramics as well as some guidance in the exploration of materials with high-performance lead-free capacitors for application in future pulsed power systems.

Improving Suspected Pulmonary Infection Diagnosis by Bronchoalveolar Lavage Fluid Metagenomic Next-Generation Sequencing: a Multicenter Retrospective Study.

Metagenomic next-generation sequencing (mNGS) has been gradually applied to clinical practice due to its unbiased characteristics of pathogen detection. However, its diagnostic performance and clinical value in suspected pulmonary infection need to be evaluated. We systematically reviewed the clinical data of 246 patients with suspected pulmonary infection from 4 medical institutions between January 2019 and September 2021. The diagnostic performances of mNGS and conventional testing (CT) were systematically analyzed based on bronchoalveolar lavage fluid (BALF). The impacts of mNGS and CT on diagnosis modification and treatment adjustment were also assessed. The positive rates of mNGS and CT were 47.97% and 23.17%, respectively. The sensitivity of mNGS was significantly higher than that of CT (53.49% versus 23.26%, P < 0.01), especially for infections of Mycobacterium tuberculosis (67.86% versus 17.86%, P < 0.01), atypical pathogens (100.00% versus 7.14%, P < 0.01), viruses (92.31% versus 7.69%, P < 0.01), and fungi (78.57% versus 39.29%, P < 0.01). The specificity of mNGS was superior to that of CT, with no statistical difference (90.32% versus 77.42%, P = 0.167). The positive predictive value (PPV) and negative predictive value (NPV) of mNGS were 97.46% and 21.88%, respectively. Diagnosis modification and treatment adjustment were conducted in 32 (32/246, 13.01%) and 23 (23/246, 9.35%) cases, respectively, according to mNGS results only. mNGS significantly improved the diagnosis of suspected pulmonary infection, especially infections of M. tuberculosis, atypical pathogens, viruses, and fungi, and it demonstrated the pathogen distribution of pulmonary infections. It is expected to be a promising microbiological detection and diagnostic method in clinical practice. IMPORTANCE Pulmonary infection is a heterogeneous and complex infectious disease with high morbidity and mortality worldwide. In clinical practice, a considerable proportion of the etiology of pulmonary infection is unclear, microbiological diagnosis being challenging. Metagenomic next-generation sequencing detects all nucleic acids in a sample in an unbiased manner, revealing the microbial community environment and organisms and improving the microbiological detection and diagnosis of infectious diseases in clinical settings. This study is the first multicenter, large-scale retrospective study based entirely on BALF for pathogen detection by mNGS, and it demonstrated the superior performance of mNGS for microbiological detection and diagnosis of suspected pulmonary infection, especially in infections of Mycobacterium tuberculosis, atypical pathogens, viruses, and fungi. It also demonstrated the pathogen distribution of pulmonary infections in the real world, guiding targeted treatment and improving clinical management and prognoses.