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A new method is proposed for detecting typical melamine dopants in food using surface-enhanced Raman scattering (SERS) biosensing technology. Melamine specific aptamer was used as the identification probe, and gold magnets (AuNPs@MNPs) and small gold nanoparticles (AuNPs@MBA) were used as the basis for Raman detection. The Raman signal of the detection system can directly detect melamine quantitatively. Under optimized conditions, the detection of melamine was carried out in the low concentration range of 0.001–500 mg/kg, the enhancement factor (EF) was 2.3 × 107, and the detection limit was 0.001 mg/kg. The method is sensitive and rapid, and can be used for the rapid detection of melamine in the field environment. [ABSTRACT FROM AUTHOR]

Objectives: Few studies comparing the effects of different types of Tai Chi exercises on preventing falls in older adults. We compared the effects for finding an optimal intervention. Methods: We searched 12 databases, including PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI) and so on, from their inception to January 13, 2023. Randomized controlled trials incorporating different types of Tai Chi for preventing falls in older adults were included. The outcome measures were the incidence of falls and Berg Balance Scale (BBS). Network meta-analysis (NMA) was conducted using Stata 15.1 based on a frequentist framework. Results: Seventeen trials were eligible, including 3470 participants and four types of Tai Chi. They were 24-form simplified Tai Chi (24-form), Yang style Tai Chi (Yang style), Sun style Tai Chi (Sun style) and Tai Chi exercise program (TCEP). In paired meta-analysis, for incidence of falls, 24-form (Relative Risk (RR) = 0.59, 95% confidence interval (CI) [0.40, 0.86]) was more efficient than the control group. For BBS outcome, 24-form (MD (mean difference) = 2.32, 95% CI [1.42, 3.22]) was better than the control group. In the NMA, the results of incidence of falls were as follows: 24-form > Yang style > Sun style > control > TCEP. The rank probability of BBS was as follows: 24-form > TCEP > Yang style > control. Conclusion: Among the four types of Tai Chi studied, the 24-form simplified Tai Chi has shown better efficacy than other types. [ABSTRACT FROM AUTHOR]

This paper proposes a discrete space vector modulation and optimized switching sequence model predictive controller for three-level neutral-point-clamped inverters in grid-connected applications. The proposed strategy is based on cascaded model predictive control (MPC) for controlling the grid current while maintaining the capacitor voltage balanced without weighting factor. To enhance the closed-loop performance, the external MPC evaluates 19 basic and 138 virtual vectors (VV) of the proposed space vector method. The optimal control voltage is then selected using an extended deadbeat method to reduce the execution time of the proposed control algorithm. By using the discrete space vector modulation principle, the VV are synthesized based on switching sequence (SS) and are divided into negative and positive SSs considering their impact on the neutral point (NP) potential. The inner MPC evaluates both types of SSs and selects the one that keeps the capacitor voltage balanced. Various controllers are evaluated and compared against the proposed control strategy. The results show that the proposed strategy improves performance without weighting factor, while maintaining a total harmonic distortion of current to be less than 2%. Compared to the modulated MPC which provides the same fixed switching frequency, the proposed controller reduces the computational burden by over 50% while also providing better NP voltage balance accuracy. [ABSTRACT FROM AUTHOR]

Recently, graph contrastive learning (GCL) has received considerable interest in graph representation learning for its robustness in capturing complex relationships between nodes in an unsupervised manner, making it suitable for unsupervised graph learning tasks such as community detection. However, most GCL approaches have two limitations when applied to community detection. First, the random augmentation strategy employed by them may destroy a graph's community structure due to the random added/removed edges or attributes. Second, nodes with similar topology or attributes may be selected as the negative samples of a target node according to their sample selection strategy, leading to the wrong assignment of the target node's community. In this paper, we propose an adaptive-graph-contrastive-learning-based community detection (AGCLCD) algorithm to address the problems. At its core, AGCLCD introduces an adaptive graph augmentation strategy to preserve a graph's original community structure in augmentation. Furthermore, we develop a composite contrastive pair selection scheme to choose the nodes sharing similar topology and attributes with a target node as its positive samples to ensure that the representation vectors of nodes in the same community are highly relevant. Comprehensive experiments on real-world and synthetic networks demonstrate that AGCLCD achieves higher accuracy and effectiveness than state-of-the-art algorithms. [ABSTRACT FROM AUTHOR]

Noninvasive brain–computer interfaces (BCIs) show great potential in applications including sleep monitoring, fatigue alerts, neurofeedback training, etc. While noninvasive BCIs do not impose any procedural risk to users (as opposed to invasive BCIs), the acquisition of high-quality electroencephalograms (EEGs) in the long term has been challenging due to the limitations of current electrodes. Herein, we developed a semidry double-layer hydrogel electrode that not only records EEG signals at a resolution comparable to that of wet electrodes but is also able to withstand up to 12 h of continuous EEG acquisition. The electrode comprises dual hydrogel layers: a conductive layer that features high conductivity, low skin-contact impedance, and high robustness; and an adhesive layer that can bond to glass or plastic substrates to reduce motion artifacts in wearing conditions. Water retention in the hydrogel is stable, and the measured skin-contact impedance of the hydrogel electrode is comparable to that of wet electrodes (conductive paste) and drastically lower than that of dry electrodes (metal pin). Cytotoxicity and skin irritation tests show that the hydrogel electrode has excellent biocompatibility. Finally, the developed hydrogel electrode was evaluated in both N170 and P300 event-related potential (ERP) tests on human volunteers. The hydrogel electrode captured the expected ERP waveforms in both the N170 and P300 tests, showing similarities in the waveforms generated by wet electrodes. In contrast, dry electrodes fail to detect the triggered potential due to low signal quality. In addition, our hydrogel electrode can acquire EEG for up to 12 h and is ready for recycled use (7-day tests). Altogether, the results suggest that our semidry double-layer hydrogel electrodes are able to detect ERPs in the long term in an easy-to-use fashion, potentially opening up numerous applications in real-life scenarios for noninvasive BCI. [ABSTRACT FROM AUTHOR]

Background: Lacrimal adenoid cystic carcinoma (LACC) is the most common orbital malignant epithelial neoplasm. LACC with high-grade transformation (LACC-HGT) has higher rates of recurrence, metastasis, and mortality than LACC without HGT. This study investigated the effects of microRNA-29a-3p (miR-29a-3p) in the pathogenesis of LACC-HGT. Methods: An Agilent human miRNA microarray was used to screen the differentially expressed miRNAs (DEMs) in LACC and LACC-HGT tumor tissues. Then, the primary cells obtained in previous studies were used to determine the effect of miR-29a-3p. Results: The expression of miR-29a-3p was abnormally lower in LACC-HGT than in LACC. miR-29a-3p can specifically target the 3ʹ UTR of Quaking mRNA and down-regulate Quaking expression, thereby inhibiting the proliferation, migration, and epithelial–mesenchymal transition of LACC cells. Conclusions: This study illustrated that miR-29a-3p functions as a tumor suppressor by down-regulating the expression of Quaking to inhibit the tumorigenesis of LACC cells. This study may also reveal the pathogenesis of HGT in LACC cells and provide a reference for LACC-HGT targeted diagnosis. [ABSTRACT FROM AUTHOR]

It is necessary to understand the molecular mechanism of banana dwarfing mutation in order to improve the high stem character of banana varieties and breed the new excellent dwarf lines. To elucidate the molecular-level regulation of banana dwarf mutations and identify the relevant genes, the complete cDNA sequence of the gibberellin 2-oxidase gene (GA2ox) in the dwarf banana and its wild type was cloned by RT-PCR and the encoded amino acid sequences bioinformatically was analyzed. Meanwhile, the expression levels of banana GA2ox gene in different tissues of dwarfed banana and its wild type were analyzed by qRT-PCR. Between the GA2ox gene sequences of the dwarf banana and its wildtype, there were 5 base pairs of variation, leading to the predicted GA2ox proteins having different molecular weights, isoelectric points, fat indices, total numbers of positive and negative charges, and hydrophilicity. In addition, the expression of GA2ox in the leaves, stalks, and fruits of dwarf banana plants was higher than that in the wild type in the early and middle stages of banana development. The results showed that the GA2ox gene may have important regulatory effects on banana stem dwarfing, the knowledge of which can help our understanding and manipulation of this important plant. [ABSTRACT FROM AUTHOR]

Egg production traits are economically important in laying ducks. Genetic molecular mechanisms and candidate genes underlying these traits remain unclear. In this study, whole genome variants were identified through whole-genome resequencing using three high-egg producing (HEN) and three low-egg producing (LEN) laying ducks. The gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genome (KEGG) pathways for the genes of common differential variants between HEN and LEN ducks were determined. Frizzled class receptor 6 (FZD6) was further genotyped using the Sequenom MassARRAY iPLEX platform. The association of FZD6 gene polymorphisms with 73 egg production and weight traits in 329 female ducks were estimated. A total of 65,535 single nucleotide polymorphisms (SNPs) and 4,702 indels were identified across the genome. Fourteen GO terms and 14 KEGG pathways were determined for the genes of common differential variants, including MAPK signaling, Wnt signaling, melanogenesis and calcium signaling pathways, which are key functional pathways for poultry egg production reported in previous reports. Further analysis showed that 27 SNPs of FZD6 were associated with three early egg production of duck and egg weight traits, including egg production at 17 weeks (EP17), 18 weeks (EP18) and 19 weeks (EP19) and egg weight at 59 weeks (EW59). The FZD6 should be considered a novel candidate gene for egg production traits in laying ducks. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was first prepared by an improved Hummers method; Fe3O4, ZrO2, and corresponding metal oxide-GO composite materials were synthesized by a hydrothermal method. The electrochemical performance of as-prepared materials modified glassy carbon electrode (GCE) was investigated by cyclic voltammetry (CV). The ternary Fe3O4-ZrO2-GO composite modified GCE was used as the electrochemical sensor for the dopamine (DA) detection. The CV test showed that the Fe3O4-ZrO2-GO composite modified GCE had a good response to DA with good stability and reproducibility. Electrochemical impedance spectroscopy (EIS) illustrated that Fe3O4-ZrO2-GO/GCE exhibited the lower Rct value (14.11 Ω). Differential pulse voltammetry (DPV) test demonstrated that the ternary composite has excellent anti-interference ability. The linear relationship by differential pulse voltammetry for Fe3O4-ZrO2-GO/GCE was Ipa(µA) = 0.2552x + 0.0056 (R2 = 0.9804) with the sensitivity of 3.649 µA µM−1 cm−2 and detection limit of 0.1562 µM in the ranges of 0.5 − 15 µM. The developed electrochemical sensor was successfully applied to the DA detection in human serum with satisfactory recovery rate. The possible synergistic amplification effect brought from Fe3O4, ZrO2, and GO for DA detection was proposed based on experimental results. [ABSTRACT FROM AUTHOR]

A series of cobalt-doped LaMnO3 (LaCo1−xMnxO3, x = 0.4, 0.5, 0.6, 1.0) perovskite electrode material were synthesized by sol–gel method and applied in catalytic oxidation for glycerol. The electrochemical tests showed that LaCo1−xMnxO3 (x = 0.4, 0.5, 0.6) exhibited more excellent electrochemical properties than undoped LaMnO3. Among which, LaCo0.4Mn0.6O3 showed the smallest onset potiential (~ 0.8 V), lowest Tafel slope (215.3 mV dec−1), and Rct value (39.07 kΩ), and its stability was even better than commercial Pt/C (20 wt%-SA). The improved electrochemical performance of LaCo1−xMnxO3 is attributed to the uneven distribution of oxygen in LaMnO3 structure caused by Co doping. [ABSTRACT FROM AUTHOR]

Indocyanine green (ICG) angiography is of great importance for ophthalmic diagnostic applications and is mainly used to check for choroidal vascular diseases. However, ICG fluorescence imaging probes aggregate in water because they have sulfonyl groups and can form dimers and oligomers. This effect thus reduces the fluorescence of the probes. Therefore, we have established a simple and effective way to prepare β-cyclodextrinmodified ICG (ICG–β-CD) via the host–guest assembly process. In contrast to ICG, ICG–β-CD avoided solution aggregation. Moreover, it exhibited improved absorption intensity. When used as an angiographic contrast agent for ophthalmic choroid examination and diagnosis in SD rats, the fluorescence imaging effect of ICG–β-CD on retinal and choroidal vessels was better than that of ICG on choroidal vessels. Therefore, ICG–β-CD is expected to achieve a "two birds with one stone" effect. [ABSTRACT FROM AUTHOR]

Antioxidants are healthy substances that are beneficial to the human body and exist mainly in natural and synthetic forms. Among many kinds of antioxidants, the natural antioxidants have great applications in many fields such as food chemistry, medical care, and clinical application. In recent years, many efforts have been made for the determination of natural antioxidants. Nano-electrochemical sensors combining electrochemistry and nanotechnology have been widely used in the determination of natural antioxidants due to their unique advantages. Therefore, a large number of nanomaterials such as metal oxide, carbon materials, and conducting polymer have attracted much attention in the field of electrochemical sensors due to their good catalytic effect and stable performance. This review mainly introduces the construction of electrochemical sensors based on different nanomaterials, such as metallic nanomaterials, metal oxide nanomaterials, carbon nanomaterials, metal–organic frameworks, polymer nanomaterials, and other nanocomposites, and their application to the detection of natural antioxidants, including ascorbic acid, phenolic acids, flavonoid, tryptophan, citric acid, and other natural antioxidants. In the end, the limitations of the existing nano-sensing technology, the latest development trend, and the application prospect for various natural antioxidant substances are summarized and analyzed. We expect that this review will be helpful to researchers engaged in electrochemical sensors. [ABSTRACT FROM AUTHOR]

The Network representation learning methods based on random walk aim to learn a low-dimensional embedding vector for each node in a network by randomly traversing the network to capture the features of nodes and edges, which is beneficial to many downstream machine learning tasks such as community detection. Most of the existing random-walk-based network representation learning algorithms emphasize the neighborhood of nodes but ignore the communities they may form and apply the same random walk strategy to all nodes without distinguishing the characteristics of different nodes. In addition, it is time-consuming to determine the most suitable random walk parameters for a given network. In this paper, we propose a novel overlapping community detection algorithm based on network representation learning which integrates community information into embedding vectors to improve the cohesion degree of similar nodes in the embedding space. First, a node-centrality-based walk strategy is designed to determine the parameters of random walk automatically to avoid the time-consuming manual selection. Second, two community-aware random walk strategies for high and low degree nodes are developed to capture the characteristics of the community centers and boundaries. The experimental results on the synthesized and real-world datasets demonstrate the effectiveness and efficiency of our algorithm on overlapping community detection compared with the state-of-the-art algorithms [ABSTRACT FROM AUTHOR]

The manifestation of skyrmions in the Mott-insulator Cu2OSeO3 originates from a delicate balance between magnetic and electronic energy scales. As a result of these intertwined couplings, the two symmetry-inequivalent magnetic ions, Cu-I and Cu-II, bond into a spin S = 1 entangled tetrahedron. However, conceptualizing the unconventional properties of this material and the energy of the competing interactions is a challenging task due to the complexity of this system. Here we combine X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering to uncover the electronic and magnetic excitations of Cu2OSeO3 with site-specificity. We quantify the energies of the 3d crystal-field splitting for both Cu-I and Cu-II, fundamental for optimizing model Hamiltonians. Additionally, we unveil a site-specific magnetic mode, indicating that individual spin character is preserved within the entangled-tetrahedron picture. Our results thus provide experimental constraints for validating theories that describe the interactions of Cu2OSeO3, highlighting the site-selective capabilities of resonant spectroscopies. The complex interactions in spin spiral systems play an important role for the emergence of multiferroicity and topological magnetic order. Here, the authors investigate the magnetism associated with the two inequivalent Cu positions in the model system Cu2OSeO3, observing site-specific electronic structure and associated magnetic excitations. [ABSTRACT FROM AUTHOR]

In this work, we synthesized bimetallic Cu nanowires@Pd (Cu NWs@Pd) by a facile replacement reaction. Benefiting from the structure anisotropy, the sensor constructed by Cu NWs@Pd with diameter of 40 nm exhibited a superior sensitivity (1363.7 ± 23.5 µA·mM−1·cm−2), which is ca. 11.06-folds higher than that for analogous Cu nanoparticles@Pd. Moreover, the synergistic effect of bimetallic metal enables the Cu NWs@Pd an enhanced sensor performance. At applied potential of 0.8 V vs Ag/AgCl, the sensitivity of Cu NWs@Pd is much higher than that of analogous Cu NWs. And the enhanced factor could reach 2.41. As 0.2 V vs Ag/AgCl was applied, detection range for the Cu NWs@Pd could up to 26.0 mM, which is ca. 1.37-folds for the pure Pd NPs. The preferable performance can be extended to the detection of H2O2. This work showed the non-enzymatic sensor with wide detection range and preferable sensitivity by Cu NWs@Pd, which would provide an efficient strategy to cope with the challenges for the commercialization of non-enzymatic sensor. [ABSTRACT FROM AUTHOR]

High cost and narrow detection range of electrocatalyst are the two major challenges for the commercialization of non-enzymatic sensor. In this work, we synthesized Cu nanowires (Cu NWs) with unique morphology and high yields were by a one-pot hydrothermal method. Different from conventional amine-assisted method, we restrained the nano-particles (NPs) formation by introducing the HCl solution. The as-prepared Cu NWs were further utilized in a non-enzymatic glucose sensor. Benefiting from the path directing effects and abundant (100) facets, the sensor constructed by Cu NWs exhibited a superior sensitivity (1001.8 µA/mM cm2) than that by analogous Cu NWs containing Cu NPs (338.3 µA/mM cm2). And the enhanced factor could reach 2.96. Moreover, the obtained Cu NWs show a wide linear response to the glucose. And the detection range could up to 25 mM, with a detection limit of 2.3 μM. This work demonstrated the preferable sensor performance of Cu NWs with uniform morphology, which opens up new avenues for utilizing 1D non-noble metals nanostructures in other sensors. [ABSTRACT FROM AUTHOR]

Lipid-like nanoparticles (LNPs) have potential as non-viral delivery systems for mRNA therapies. However, repeated administrations of LNPs may lead to accumulation of delivery materials and associated toxicity. To address this challenge, we have developed biodegradable lipids which improve LNPs clearance and reduce toxicity. We modify the backbone structure of Dlin-MC3-DMA by introducing alkyne and ester groups into the lipid tails. We evaluate the performance of these lipids when co-formulated with other amine containing lipid-like materials. We demonstrate that these formulations synergistically facilitate robust mRNA delivery with improved tolerability after single and repeated administrations. We further identify albumin-associated macropinocytosis and endocytosis as an ApoE-independent LNP cellular uptake pathway in the liver. Separately, the inclusion of alkyne lipids significantly increases membrane fusion to enhance mRNA release, leading to synergistic improvement of mRNA delivery. We believe that the rational design of LNPs with multiple amine-lipids increases the material space for mRNA delivery. Lipid-like nanoparticles have applications as non-viral delivery systems for mRNA. Here, the authors develop biodegradable lipids with improved clearance and reduced toxicity. [ABSTRACT FROM AUTHOR]

Gaining precise control over the cellular entry pathway of nanomaterials is key in achieving cytosolic delivery, accessing subcellular environments, and regulating toxicity. However, this precise control requires a fundamental understanding of the behavior of nanomaterials at the bio-nano interface. Herein, we report a computational study investigating the synergistic effect of several key physicochemical properties of nanomaterials on their cellular entry pathways. By examining interactions between monolayer-protected nanoparticles and model cell membranes in a three-dimensional parameter space of size, surface charge/pKa, and ligand chemistry, we observed four different types of nanoparticle translocation for cellular entry which are: outer wrapping, free translocation, inner attach, and embedment. Nanoparticle size, surface charge/pKa, and ligand chemistry each play a unique role in determining the outcome of translocation. Specifically, membrane local curvature induced by nanoparticles upon contact is critical for initiating the translocation process. A generalized paradigm is proposed to describe the fundamental mechanisms underlying the bio-nano interface. Lin et al. investigate interactions between monolayer-protected nanoparticles and model cell membranes, and show four different types of nanoparticle translocation, i.e., outer wrapping, free translocation, inner attach, and embedment. The different translocation types greatly depend on synergism between nanoparticle size, surface charge, and ligand chemistry. [ABSTRACT FROM AUTHOR]

Electron correlations play a dominant role in the charge dynamics of the cuprates. We use resonant inelastic X-ray scattering (RIXS) to track the doping dependence of the collective charge excitations in electron doped La 2 − x Ce x CuO 4 (LCCO). From the resonant energy dependence and the out-of-plane momentum dependence, the charge excitations are identified as three-dimensional (3D) plasmons, which reflect the nature of the electronic structure and Coulomb repulsion on both short and long lengthscales. With increasing electron doping, the plasmon excitations increase monotonically in energy, a consequence of the electron correlation effect on electron structure near the Fermi surface (FS). Importantly, the plasmon excitations evolve from a broad feature into a well-defined peak with much increased life time, revealing the evolution of the electrons from incoherent states to coherent quasi-particles near the FS. Such evolution marks the reduction of the short-range electronic correlation, and thus the softening of the Mottness of the system with increasing electron doping. [ABSTRACT FROM AUTHOR]

The Ba0.985Ca0.005Ti0.98Sn0.02O3 + x mol% MnO2 (BCTSMx, x = 0, 0.2, 0.3, 0.4, 0.5 and 0.6) ceramics were fabricated by conventional solid-state reaction method. The effects of MnO2 doping on the phase structure, microstructure, dielectric, ferroelectric and piezoelectric properties of Ba0.985Ca0.005Ti0.98Sn0.02O3 ceramics were investigated systematically. X-ray diffraction patterns revealed that the BCTSMx ceramics are composed of coexisting tetragonal-orthogonal phases. The addition of MnO2 could significantly improve the sinterability of BCTS ceramics. The BCTSMx ceramics with x = 0.4 demonstrated an optimum electrical properties: εr = 2802, tanδ = 0.081, TC = 121 °C, εmax = 9977, Pr = 11.8 μC/cm2, EC = 2.6 kV/cm, bipolar Smax = 0.25%, unipolar Smax = 0.28%, d33* = 1093 pm/V, d33 = 325 pC/N, kp = 43.2%, and Qm = 118. [ABSTRACT FROM AUTHOR]

Therapeutic messenger RNA vaccines enable delivery of whole antigens, which can be advantageous over peptide vaccines. However, optimal efficacy requires both intracellular delivery, to allow antigen translation, and appropriate immune activation. Here, we developed a combinatorial library of ionizable lipid-like materials to identify mRNA delivery vehicles that facilitate mRNA delivery in vivo and provide potent and specific immune activation. Using a three-dimensional multi-component reaction system, we synthesized and evaluated the vaccine potential of over 1,000 lipid formulations. The top candidate formulations induced a robust immune response, and were able to inhibit tumor growth and prolong survival in melanoma and human papillomavirus E7 in vivo tumor models. The top-performing lipids share a common structure: an unsaturated lipid tail, a dihydroimidazole linker and cyclic amine head groups. These formulations induce antigen-presenting cell maturation via the intracellular stimulator of interferon genes (STING) pathway, rather than through Toll-like receptors, and result in limited systemic cytokine expression and enhanced anti-tumor efficacy. Combinatorial development of heterocyclic lipidoids yields efficient mRNA vaccine vehicles that activate immune cells via the STING pathway. [ABSTRACT FROM AUTHOR]

An efficient and practical protocol for the synthesis of chromenes derivatives catalyzed by a low-loading sodium ethylene diamine tetraacetate (2 mol%) as a catalyst via multicomponent reaction is reported. A wide range of aromatic aldehydes easily undergo condensations with malononitrile and 4-hydroxycoumarin (4-hydroxy-6-methyl-2-pyrone or dimedone) under mild conditions to afford the desired products of good purity in excellent yields. This protocol has several advantages, such as mild conditions, high yields, and an inexpensive catalyzed system. [ABSTRACT FROM AUTHOR]

The Ba Ca Zr Ti (BCZT) nano-particles were modified by polyimide (PI) through a chemical coating method. And the PI@BCZT/polyvinylidene fluoride (PVDF) flexible composite films were fabricated by solution casting method. The transmission electron microscopy and scanning electron microscopy results show that the nano-particles is about 50 nm, PI is uniformly coated on the surface of BCZT nano-particles about 7-10 nm as well as there are uniform and improved dispersion in the matrix after modification. A series of dielectric properties were carried out. The results show the 50 vol% composites own a remarkably enhanced dielectric permittivity (ε = 130) at 100 Hz. After modification, the breakdown strength has increased from 20 to 96 kV mm and the loss tangent is reduced from 1.8 to 0.2 at 100 Hz compare with un-modified composites in 40 vol% dopant. With the increase of dopant, ferroelectricity of composites can be enhanced. The optimal residual polarization is 40 vol% PI@BCZT composites, which possess 1.025 μC/cm under 50 kV/mm external electric field. In addition, after modification, thermo-gravimetric analysis exhibits the degradation temperature Td and Td of PI@BCZT/PVDF composites can be enhanced about 5-10 °C and show better thermal stability than un-modified composites. [ABSTRACT FROM AUTHOR]

Most polymers used as energy storage have a low operating temperature that limits the broad applications of capacitors. In this paper, PI was used as the polymer matrix, which endowed the KTN/PI composite film with an ultrahigh thermal decomposition temperature (~550 °C). In the designed three-layer-structured KTN/PI composite films, pure PI is employed as a middle layer while KTN nanoparticles are introduced in two outer layers. It is found that the three-layer-structured KTN/PI composite film could achieve a higher energy density (3.0 J/cm) than the single-layer-structured KTN/PI composite film (1.5 J/cm) by modulating distribution of its local electric field. The three-layer structure has been proved to be quite effective in enhancing the composite films' breakdown strength and increasing their energy density and discharge efficiency. [ABSTRACT FROM AUTHOR]

A novel all-organic composite comprising polyvinylidene fluoride (PVDF) and diisopropylammonium bromide (DIPAB) crystal particles (0-20 mass%) with significant dielectric properties has been synthesized via coating method. The DIPAB crystal nano-particles were prepared in the PVDF matrix by in situ growth method, which were found effective in transforming structure and enhancing the dielectric properties of the composites. X-ray diffraction pattern and Fourier transform infrared spectroscopy confirmed that the DIPAB in situ particles can improve the content of the electroactive β phase nucleation in PVDF matrix, whereas the PVDF matrix could induce the (00 l) preferred orientation of the DIPAB nano-crystal. And the dielectric performance of the DIPAB/PVDF composite was significant influenced by the enhanced electroactive β phase and (00l) textured DIPAB. Relative dielectric constants as high as 94 was obtained at 40 Hz with 5 mass% DIPAB filler, which is 11-fold higher than that of the pure PVDF matrix (~8.5). The breakdown strength decreased as the mass fraction of DIPAB increased but still stayed more than 38.9 kV/mm. [ABSTRACT FROM AUTHOR]

The structural and electronic properties of lead-free potassium tantalite niobate KTaNbO (KTN) with A site vacancies $$ V_{\rm{K}}^{0} $$ , $$ V_{\rm{K}}^{1 - } $$ and oxygen vacancies $$ V_{\rm{O}}^{0} $$ , $$ V_{\rm{O}}^{2 + } $$ , were investigated by first-principles calculations, which indicated that A site vacancies $$ V_{\rm{K}}^{0} $$ are likely to form in the KTN compared with $$ V_{\rm{K}}^{1 - } $$ , and oxygen vacancies $$ V_{\rm{O}}^{2 + } $$ are likely to form compared with $$ V_{\rm{O}}^{0} $$ in the KTN according to the investigation of formation energy. The results show that K and O vacancies have significant influence on the atomic interactions of the atoms and the electronic performance of the materials. And Ta atoms are more easily influenced by the K and O vacancies than the Nb atoms from the atomic displacements in KTN with K and O vacancies. The investigation of density of state indicates that the compensation of electrons in KTN with vacancies make the hybridization become stronger among Ta d, Nb d and O p orbitals. Besides, Mulliken population of all the Ta and Nb atoms in KTN with charged vacancies are influenced by complement electrons. The strength of the Nb-O bond is stronger than Ta-O based on the changes of bond lengths and Mulliken population. [ABSTRACT FROM AUTHOR]

KTaNbO (KTN) nanoparticles with a perovskite structure were synthesized in orthogonal experiments under different hydrothermal conditions. Controlled sizes were generated by analyzing four variables using an orthogonal array experimental design (OA matrix): reaction temperature, KOH concentration, reaction time and solution volume. The effects of the four factors on the KTN nanoparticle size were systematically examined using range analysis and analysis of variance. The KOH concentration had the largest effect on the average size of the KTN nanoparticles. The KTN particles with a designed grain size can be obtained by controlling the four effect factors. [ABSTRACT FROM AUTHOR]

The hybrid films of well dispersed SiO nanoparticle in polyimide (PI/SiO) were prepared through the sol-gel processing. The pure PI was synthesized from 4, 4′,-oxydianaline (ODA) and pyromellitic dianhydride (PMDA). The residual amino groups which were controlled by the reactant stoichiometric ratio reacted with the coupling agent isocyanatopropyltriethoxysilane (ICTOS) to provide an organic-inorganic bonding. A series amount of tetraethoxysilane (TEOS) was then added, thus producing chemically bonded composite films. The films with different silica contents (0 wt %, 5 wt %, 8 wt %, 10 wt %, 13 wt %, and 15 wt %) were characterized by a variety of techniques including FT-IR, SEM, TGA, and tensile analysis. The results indicated that the chemical interaction between the two phases resulted in the formation of well-dispersed nanoparticles (20-30 nm) in the PI matrix, and superior thermal stability of hybrid films. The tensile measurement showed that the mechanical properties were markedly improved with incorporating various amount of silica, and the maximum of tensile strength was 105.4 MPa with10 wt % of silica concentration. [ABSTRACT FROM AUTHOR]

The manifestation of skyrmions in the Mott-insulator Cu2OSeO3 originates from a delicate balance between magnetic and electronic energy scales. As a result of these intertwined couplings, the two symmetry-inequivalent magnetic ions, Cu-I and Cu-II, bond into a spin S = 1 entangled tetrahedron. However, conceptualizing the unconventional properties of this material and the energy of the competing interactions is a challenging task due to the complexity of this system. Here we combine X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering to uncover the electronic and magnetic excitations of Cu2OSeO3 with site-specificity. We quantify the energies of the 3d crystal-field splitting for both Cu-I and Cu-II, fundamental for optimizing model Hamiltonians. Additionally, we unveil a site-specific magnetic mode, indicating that individual spin character is preserved within the entangled-tetrahedron picture. Our results thus provide experimental constraints for validating theories that describe the interactions of Cu2OSeO3, highlighting the site-selective capabilities of resonant spectroscopies. The complex interactions in spin spiral systems play an important role for the emergence of multiferroicity and topological magnetic order. Here, the authors investigate the magnetism associated with the two inequivalent Cu positions in the model system Cu2OSeO3, observing site-specific electronic structure and associated magnetic excitations. [ABSTRACT FROM AUTHOR]

Currently, light pollution has become a nonnegligible issue in our daily life. Artificial light sources with high color temperature were deem to be the major pollution source, which could induce several adverse effects on human's health. In our previous research, we have firstly developed an artificial indoor light with low color temperature (1900 K). However, the biological effects of this artificial light on human's health are unclear. Here, four artificial lights (1900 K, 3000 K, 4000 K and 6600 K) were used to evaluate some biological changes in both human (in total 152 person-times) and murine models. Compared with other three high color temperature artificial lights, our lights (1900 K) presented a positive effect on promoting the secreting of melatonin and glutamate, protecting human's eyes, accelerating would healing and hair regeneration. These systematical studies indicated that the proposed low color temperature (1900 K) light could provide several significant benefits in human's daily life. [ABSTRACT FROM AUTHOR]

In this work, we synthesized bimetallic Cu nanowires@Pd (Cu NWs@Pd) by a facile replacement reaction. Benefiting from the structure anisotropy, the sensor constructed by Cu NWs@Pd with diameter of 40 nm exhibited a superior sensitivity (1363.7 ± 23.5 µA·mM−1·cm−2), which is ca. 11.06-folds higher than that for analogous Cu nanoparticles@Pd. Moreover, the synergistic effect of bimetallic metal enables the Cu NWs@Pd an enhanced sensor performance. At applied potential of 0.8 V vs Ag/AgCl, the sensitivity of Cu NWs@Pd is much higher than that of analogous Cu NWs. And the enhanced factor could reach 2.41. As 0.2 V vs Ag/AgCl was applied, detection range for the Cu NWs@Pd could up to 26.0 mM, which is ca. 1.37-folds for the pure Pd NPs. The preferable performance can be extended to the detection of H2O2. This work showed the non-enzymatic sensor with wide detection range and preferable sensitivity by Cu NWs@Pd, which would provide an efficient strategy to cope with the challenges for the commercialization of non-enzymatic sensor. [ABSTRACT FROM AUTHOR]