Anion-induced robust ferroelectricity in sulfurized pseudo-rhombohedral epitaxial BiFeO3 thin films via polarization rotation

Polarization rotation caused by various strains, such as substrate and/or chemical strain, is essential to control the electronic structure and properties of ferroelectric materials. This study proposes anion-induced polarization rotation with chemical strain, which effectively improves ferroelectricity. A method for the sulfurization of BiFeO3 thin films by introducing sulfur anions is presented. The sulfurized films exhibited substantial enhancement in room-temperature ferroelectric polarization through polarization rotation and distortion, with a 170% increase in the remnant polarization from 58 to 100.7 μC cm−2. According to first-principles calculations and the results of X-ray absorption spectroscopy and high-angle annular dark-field scanning transmission electron microscopy, this enhancement arose from the introduction of S atoms driving the re-distribution of the lone-pair electrons of Bi, resulting in the rotation of the polarization state from the [001] direction to the [110] or [111] one. The presented method of anion-driven polarization rotation might enable the improvement of the properties of oxide materials.This work was supported by the National Key Research and Development Program of China (2018YFA0703700, 2017YFE0119700, 2021YFA1400300 and 2018YFA0305700), the National Natural Science Foundation of China (21801013, 51774034, 22271309, 11721404, 11934017, 12261131499, and 51961135107), the Fundamental Research Funds for the Central Universities (FRF-IDRY-19-007 and FRF-TP-19-055A2Z), the National Program for Support of Top-notch Young Professionals, the Young Elite Scientists Sponsorship Program by CAST (2019-2021QNRC), the Beijing Natural Science Foundation (Z200007), and the Chinese Academy of Sciences (XDB33000000). This research used the resources of the Beijing Synchrotron Radiation Facility (1W1A and 4B9B beamlines) of the Chinese Academy of Science.Peer reviewe

Synergistic Modification Induced Specific Recognition between Histone and TRIM24 via Fluctuation Correlation Network Analysis.

Histone modification plays a key role in gene regulation and gene expression. TRIM24 as a histone reader can recognize histone modification. However the specific recognition mechanism between TRIM24 and histone modification is unsolved. Here, systems biology method of dynamics correlation network based on molecular dynamics simulation was used to answer the question. Our network analysis shows that the dynamics correlation network of H3K23ac is distinctly different from that of wild type and other modifications. A hypothesis of "synergistic modification induced recognition" is then proposed to link histone modification and TRIM24 binding. These observations were further confirmed from community analysis of networks with mutation and network perturbation. Finally, a possible recognition pathway is also identified based on the shortest path search for H3K23ac. Significant difference of recognition pathway was found among different systems due to methylation and acetylation modifications. The analysis presented here and other studies show that the dynamic network-based analysis might be a useful general strategy to study the biology of protein post-translational modification and associated recognition

Synergistic Modification Induced Specific Recognition between Histone and TRIM24 via Fluctuation Correlation Network Analysis.

Histone modification plays a key role in gene regulation and gene expression. TRIM24 as a histone reader can recognize histone modification. However the specific recognition mechanism between TRIM24 and histone modification is unsolved. Here, systems biology method of dynamics correlation network based on molecular dynamics simulation was used to answer the question. Our network analysis shows that the dynamics correlation network of H3K23ac is distinctly different from that of wild type and other modifications. A hypothesis of "synergistic modification induced recognition" is then proposed to link histone modification and TRIM24 binding. These observations were further confirmed from community analysis of networks with mutation and network perturbation. Finally, a possible recognition pathway is also identified based on the shortest path search for H3K23ac. Significant difference of recognition pathway was found among different systems due to methylation and acetylation modifications. The analysis presented here and other studies show that the dynamic network-based analysis might be a useful general strategy to study the biology of protein post-translational modification and associated recognition

A preliminary study on the application of PspA as a carrier for group A meningococcal polysaccharide.

This study aimed to explore the feasibility of pneumococcal surface protein A (PspA) as a carrier protein. Three recombinant pneumococcal surface proteins from three different clades were expressed by the prokaryotic expression system and conjugated to group A meningococcal polysaccharide (GAMP) to generate three polysaccharide-protein conjugates. The conjugates, unconjugated proteins, GAMP, and GAMP-TT vaccine bulk (used as positive control) were immunized into mice, and their immune effects were assessed by the methods of enzyme-linked immunosorbent assay (ELISA), flow cytometry (FCM), and serum bactericidal assay (SBA). The results showed that the polysaccharide-protein conjugates could produce higher levels of anti-GAMP IgG titers (P < 0.05), higher ratios of Th1/Th2 (P < 0.05), and higher levels of serum bactericidal activity (P < 0.05), compared with the unconjugated GAMP. The conjugation of PspAs to GAMP also enhanced the anti-PspA responses compared with unconjugated PspAs except for PspA3. In conclusion, the results indicated that the three PspAs were appropriate carrier proteins, as demonstrated by the characteristics of T-cell dependent responses to the GAMP, and might protect against group A of epidemic cerebrospinal meningitis

Study on electrical conductivity and microwave absorption properties of CNTs/CB/PMMA nanocomposites foam

In order to study the conductive and microwave absorption performance of multi-dimensional multiphase filler conductive foam composites, carbon nanotubes (CNTs)/carbon black (CB)/polymethyl methacrylate (PMMA) nanocomposites with different porosity were fabricated via supercritical carbon dioxide (ScCO _2 ) one-step physical constraint foaming technology. The effects of filler component and porosity on the conductivity and absorbing properties of CNTs/PMMA/CB composite foam were studied. The Monte-Carlo method was used to study the percolation of composites and the effect of introduced microcells on the conductive network of multi-dimensional fillers. The results revealed that the volume conductivity of CNTs(3 vol%)/PMMA composites increased from 0.88 S m ^−1 to 3.31 S m ^−1 after the addition of 1 vol% CB. CNTs and CB had obvious synergistic effect on improving the conductivity of the composites, and the microwave absorption efficiency rose from 12.6 dB to 17.2 dB. With the increase of porosity, the electromagnetic wave absorption peak of CNTs/CB/PMMA composite foam moved to low frequency, while the conductivity showed a first rise and then a decline. The simulated percolation probability obtained by representative volume element (RVE) with different porosity also showed a similar trend, which turned out that with the increase of porosity, the effect of microcells on the convertion of conductive network construction from promoting to inhibiting

Progress in diagnosis and treatment of difficult-to-treat asthma in children

At present, medications containing inhaled corticosteroids (ICS-containing) are the keystones of asthma treatment. The majority of asthmatic children can significantly improve clinical outcomes with little worsening by standardized inhaled glucocorticoid treatment, but there is still a small proportion of children who are unable to achieve good symptom control even after the maximum standardized treatment, known as ‘children with difficult-to-treat asthma (DA)’. The high heterogeneity of DA makes therapy challenging and expensive, which poses a serious risk to children’s health and makes it extremely difficult for clinical physicians to accurately identify and treat children with DA. This article reviews the definition, evaluation, and treatment of this asthma in order to provide a reference for optimal clinical decision-making

A 1.6-Mb microdeletion in chromosome 17q22 leads to NOG-related symphalangism spectrum disorder without intellectual disability.

Microdeletions in chromosome 17q22, where the NOG gene resides, have been reported leading to the NOG-related symphalangism spectrum disorder (NOG-SSD), intellectual disability and other developmental abnormalities. In this study we reported a dominant Chinese Han family segregating with typical NOG-SSD symptoms including proximal symphalangism, conductive hearing loss, amblyopia and strabismus, but not intellectual disability. Sanger sequencing identified no pathogenic mutation in the coding regions of candidate genes NOG, GDF5 and FGF9. SNP genotyping in the genomic region surrounding NOG identified loss of heterozygosity in the affected family members. By array comparative genomic hybridization and quantitative real-time polymerase chain reaction, we identified and mapped the breakpoints of a novel 1.6-Mb microdeletion in chromosome 17q22 that included NOG and twelve other genes. It is the first microdeletion reported in chromosome 17q22 that is associated with NOG-SSD only but not with intellectual disability. Our results may help identifying the dosage sensitive genes for intellectual disability and other developmental abnormalities in chromosome 17q22. Our study also suggested that genomic deletions in chromosome 17q22 should be screened in the NOG-SSD patients in which no pathogenic mutation is identified by conventional sequencing methods