Ferroelectric Photovoltaic Effect

Tetragonal BiFeO3 films with the thickness of 30 nm were grown epitaxially on (001) oriented LaAlO3 substrate by using pulsed laser deposition (PLD). The transverse photovoltaic effects were studied as a function of the sample directions in-plane as well as the angle between the linearly polarized light and the plane of the sample along X and Y directions. The absorption onset and the direct band gap are ~2.25 and ~2.52 eV, respectively. The photocurrent depends not only on the sample directions in-plane but also on the angle between the linearly polarized light and the plane of the sample along X and Y directions. The results indicate that the bulk photovoltaic effect together with the depolarization field was ascribed to this phenomenon. Detailed analysis presents that the polarization direction is along [110] direction and this depolarization field induced photocurrent is equal to ~3.53 μA/cm2. The BPV induced photocurrent can be approximate described as Jx ≈ 2.23cos(2θ), such an angular dependence of photocurrent is produced as a consequence of asymmetric microscopic processes of carriers such as excitation and recombination

Influence of Co ion doping on the microstructure, magnetic and dielectric properties of Ni1-xCoxFe2O4 ceramics

Ni1-xCoxFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8) ceramics were prepared by chemical co-precipitation method and the effect of Co ion doping on the microstructure, magnetic and dielectric properties has been investigated. The results show that the synthesized ceramics display only spinel phase of Ni1-xCoxFe2O4, without other apparent impurities found. The lattice of Ni1-xCoxFe2O4 crystal structure was distorted as a result of the incorporation of Co ion, and the lattice parameters increase with the increase of Co ion content. The grain size decreases slightly with increasing the content of Co ion, indicating a change of particle size and morphology at higher doping content. The results of impedance analysis shows that the sample doped with 80 at.% Co possesses the maximal dielectric constant, while the pure NiFe2O4 sample shows the minimal value when the frequency is below 0.1 MHz. The M-H loops of these ceramics exhibit highly magnetic nature and the saturation magnetization. The remnant magnetization increases linearly with the increase of Co-concentration in nickel ferrite while the coercive field (Hc) shows non-monotonic variation with Co content. The minimal and maximal values of Hc can be obtained when the Co concentrations are 40 and 80 at.%, respectively. The highest value of the saturation magnetization is 63 emu/g obtained with 80 at.% Co doping while the lowest value is ∼31 emu/g for the pure NiFe2O4 ceramics. The abnormal magnetic behaviour is due to the A-B super exchange interaction when magnetic Co2+ ions are added

Dielectric, ferroelectric and magnetic properties of Bi0.78La0.08Sm0.14Fe0.85Ti0.15O3 ceramics prepared at different sintering conditions

Although BiFeO3 (BFO) has attracted great attention due to its special physical properties as a typical single phase multiferroic material, the application is limited due to the formation of impurities, defects and so forth. Herein, we report improved multiferroic properties of Bi0.78La0.08Sm0.14Fe0.85Ti0.15O3 (BLSFTO) ceramics by combination of co-doping and sintering schedule. BLSFTO multiferroic ceramics were prepared by using the conventional solid state reaction method and the effect of sintering time (2, 5, 10, 20 and 30 h) on the structural, dielectric and multiferroic properties was investigated systematically. The result indicates that stable BLSFTO phase with perovskite structure was formed for all the samples. Only some impurities such as Bi2O4 can be observed when the sintering time is longer than 20 h, indicating that the sintering time can induce structural changes in BLSFTO and too long sintering time can remarkably increase the secondary phases. In addition, the frequency dependent dielectric properties show that sintering time has distinct effect on the frequency stability and the relaxation process. The result demonstrates that the enhanced magnetization, improved dielectric and ferroelectric properties may be correlated with the structural transformation, impurities, oxygen vacancies and grain morphology

High level of reactive oxygen species inhibits triacylglycerols accumulation in Chlamydomonas reinhardtii

Many microalgae accumulate large amounts of lipid droplets (LDs) following N deprivation. The triacylglycerols (TAGs) in these LDs can be used as a feedstock to produce biodiesel. To investigate the molecular mechanism underlying LD formation, we used a percoll gradient-based method to enrich for mutants with defects in LD formation and generated an insertional mutagenesis library containing > 11,000 Chlamydomonas reinhardtii transformants. One of the mutants harbored a mutation in a gene encoding a glutathione peroxidase (GPX5) that catalyzes the formation of water from hydrogen peroxide (H2O2) or organic hydroperoxide. The gpx5 mutant had a 35% reduction in the number of LDs and a 50% reduction in TAG content compared with the parental strain CC4348 at 24 h of N deprivation. The full-length of GPX5 or truncate GPX5 without the putative signal peptide or the putative signal peptide of GPX5 fused YFP localized in the cytoplasm, but not in chloroplasts. Complementation with full-length GPX5 rescued the mutant phenotypes, and the expression of GPX5 in a complemented strain L27 was increased 2-3 fold after 24 h of N deprivation. Moreover, the gpx5 mutant showed increased sensitivity to the singlet oxygen (O-1(2)) stress generated by the photosensitizer Rose Bengal (RB). The ROS concentration of the gpx5 was about 1.5 times that of CC4348 during N deprivation. Artificial increasing of ROS concentration in cells abolished the formation of LDs in Chlamydomonas. These data suggest that a high level of ROS attenuates LD formation

Decellularized Periosteum-Derived Hydrogels Promote the Proliferation, Migration and Osteogenic Differentiation of Human Umbilical Cord Mesenchymal Stem Cells

Human umbilical cord mesenchymal stem cells (hUCMSCs) are promising for bone tissue engineering, which have a non-invasive harvesting process, high cell yield, favorable proliferation capacity, and low immunogenicity. However, the osteogenic efficacy of hUCMSCs is relatively lower than that of bone marrow mesenchymal stem cells (BMSCs). Hydrogels from decellularized extracellular matrix (dECM) preserve the biological compositions and functions of natural ECM, which can provide tissue-specific cues to regulate phenotypic expression and cell fate. It is unknown, however, whether hydrogels from periosteum can serve as pro-osteogenic carriers of hUCMSCs. Herein, a decellularized periosteum-derived hydrogel (dPH) was fabricated to reveal the effects of periosteum-specific cues on the bioactivities of hUCMSCs. A widely used non-bone/periosteum-derived ECM hydrogel product, Matrigel, was used as the control group. After decellularization, the absence of nuclei in the histological analysis indicated a successful removal of cellular components, which was also confirmed by DNA content quantification. The storage modulus of dPH increased (from 164.49 ± 29.92 Pa to 855.20 ± 20.67 Pa) with increasing concentration (from 0.5% to 1%). With a highly porous, fibrous microstructure, dPH had a more hydrophilic surface than Matrigel, of which the water contact angle reduced 62.62 ± 0.04%. Furthermore, dPH prominently promoted the initial cellular spreading with a significantly higher cell surface area (1.47-fold), cell spreading length (1.45-fold) and proliferation (approximately 1.05–1.13-fold) of hUCMSCs than those of Matrigel. Additionally, dPH was conducive to cell migration, whereas no cells migrated to Matrigel in the Transwell model. Compared with those of the Matrigel group, the osteogenesis-related genes expression levels (runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN)) and mineralized matrix formation (9.74-fold) of the hUCMSCs significantly increased in the dPH group. Our study indicated that dPH could provide a pro-osteogenic microenvironment for hUCMSCs, thereby revealing a promising application potential to repair bone defects

Digital Twins-Based Production Line Design and Simulation Optimization of Large-Scale Mobile Phone Assembly Workshop

The mobile phone is a typical 3C electronic product characterized by frequent replacement, multiple product specifications, high flexibility, high-frequency production line switching, and urgent delivery time during production. Therefore, the optimized design of the mobile phone production workshop is crucial. This paper takes the assembly process of a specific type of mobile phone assembly as the research object and adopts the heuristic balance method to combine the production procedures. Moreover, it considers the automation degree of the process and the demand for production line rhythm to carry out station division and working hours design for the assembly process. The advantages and disadvantages of the plug-and-play production line and unit production line architecture are integrated, aiming at the production line’s construction cost and unit area capacity. A hybrid workshop with a mixed combination of two types of production lines is designed and an optimization model of hybrid workshop design is established. The semi-physical simulation technology of digital twins is utilized to verify the proposed design scheme to achieve the balance optimization of the production line, improve production efficiency, and reduce production costs. This work provides a technical scheme for designing and optimizing large-scale mobile phone assembly workshops with multi-batch and high-frequency production changes

Metabolome and Transcriptome Integrated Analysis of <i>Mulberry</i> Leaves for Insight into the Formation of Bitter Taste

Mulberry leaves are excellent for health care, confirmed as a ‘drug homologous food’ by the Ministry of Health, China. The bitter taste of mulberry leaves is one of the main problems that hinders the development of the mulberry food industry. The bitter, unique taste of mulberry leaves is difficult to eliminate by post-processing. In this study, the bitter metabolites in mulberry leaves were identified as flavonoids, phenolic acids, alkaloids, coumarins and L-amino acids by a combined analysis of the metabolome and transcriptome of mulberry leaves. The analysis of the differential metabolites showed that the bitter metabolites were diverse and the sugar metabolites were down-regulated, indicating that the bitter taste of mulberry leaves was a comprehensive reflection of various bitter-related metabolites. Multi-omics analysis showed that the main metabolic pathway related to bitter taste in mulberry leaves was galactose metabolism, indicating that soluble sugar was one of the main factors of bitter taste difference in mulberry leaves. Bitter metabolites play a great role in the medicinal and functional food of mulberry leaves, but the saccharides in mulberry leaves have a great influence on the bitter taste of mulberry. Therefore, we propose to retain bitter metabolites with drug activity in mulberry leaves and increase the content of sugars to improve the bitter taste of mulberry leaves as strategies for mulberry leaf food processing and mulberry breeding for vegetable use

Screening and Verification of Photosynthesis and Chloroplast-Related Genes in Mulberry by Comparative RNA-Seq and Virus-Induced Gene Silencing

Photosynthesis is one of the most important factors in mulberry growth and production. To study the photosynthetic regulatory network of mulberry we sequenced the transcriptomes of two high-yielding (E1 and E2) and one low-yielding (H32) mulberry genotypes at two-time points (10:00 and 12:00). Re-annotation of the mulberry genome based on the transcriptome sequencing data identified 22,664 high-quality protein-coding genes with a BUSCO-assessed completeness of 93.4%. A total of 6587 differentially expressed genes (DEGs) were obtained in the transcriptome analysis. Functional annotation and enrichment revealed 142 out of 6587 genes involved in the photosynthetic pathway and chloroplast development. Moreover, 3 out of 142 genes were further examined using the VIGS technique; the leaves of MaCLA1- and MaTHIC-silenced plants were markedly yellowed or even white, and the leaves of MaPKP2-silenced plants showed a wrinkled appearance. The expression levels of the ensiled plants were reduced, and the levels of chlorophyll b and total chlorophyll were lower than those of the control plants. Co-expression analysis showed that MaCLA1 was co-expressed with CHUP1 and YSL3; MaTHIC was co-expressed with MaHSP70, MaFLN1, and MaEMB2794; MaPKP2 was mainly co-expressed with GH9B7, GH3.1, and EDA9. Protein interaction network prediction revealed that MaCLA1 was associated with RPE, TRA2, GPS1, and DXR proteins; MaTHIC was associated with TH1, PUR5, BIO2, and THI1; MaPKP2 was associated with ENOC, LOS2, and PGI1. This study offers a useful resource for further investigation of the molecular mechanisms involved in mulberry photosynthesis and preliminary insight into the regulatory network of photosynthesis

Electric Control of the Hall effect in Pt/Bi0.9La0.1FeO3 bilayers.

Platinum metal, being nonmagnetic and with a strong spin-orbit coupling interaction, has been deposited on weak ferromagnetic Bi0.9La0.1FeO3 thin films. The Hall effect is studied as a function of the polarization direction of multiferroic Bi0.9La0.1FeO3 thin films, as well as magnetic field (H) and temperature (T). For the two polarization directions, besides the obvious difference of the anomalous Hall resistance RAH, it increases sharply with decreasing temperature, and even changes sign, thus violating the conventional expression. This observations indicate local magnetic moments in Pt caused by the local electric fields at the interface of Bi0.9La0.1FeO3 films. Also, possible proximity effects and induced magnetic ordering in Pt on weak ferromagnetic Bi0.9La0.1FeO3 thin films of both upward and downward polarization states may exist and their contribution to the spin-related measurements should not be neglected

Voting-Based Contour-Aware Framework for Medical Image Segmentation

Accurate and automatic segmentation of medical images is in increasing demand for assisting disease diagnosis and surgical planning. Although Convolutional Neural Networks (CNNs) have shown great promise in medical image segmentation, they prefer to learn texture features over shape information. Moreover, recent studies have shown the promise that learning the data in a meaningful order can make the network perform better. Inspired by these points, we aimed to propose a two-stage medical image segmentation framework based on contour-aware CNN and voting strategy, which could consider the contour information and a meaningful learning order. In the first stage, we introduced a plug-and-play contour enhancement module that could be integrated into the encoder–decoder architecture to assist the model in learning boundary representations. In the second stage, we employed a voting strategy to update the model using easy samples in order to further increase the performance of our model. We conducted studies of the two publicly available CHAOS (MR) and hippocampus MRI datasets. The experimental results show that, when compared to the recent and popular existing models, the proposed framework can boost overall segmentation accuracy and achieve compelling performance, with dice coefficients of 91.2 ± 2.6% for the CHAOS dataset and 88.2 ± 0.4% for the hippocampus dataset