Spin–orbit torques (SOTs), which rely on spin current generation from charge current in a nonmagnetic material, promise an energy-efficient scheme for manipulating magnetization in magnetic devices. ...A critical topic for spintronic devices using SOTs is to enhance the charge to spin conversion efficiency. Besides, the current-induced spin polarization is usually limited to in-plane, whereas out-of-plane spin polarization could be favored for efficient perpendicular magnetization switching. Recent advances in utilizing two important classes of two-dimensional materialstopological insulators and transition-metal dichalcogenidesas spin sources to generate SOT shed light on addressing these challenges. Topological insulators such as bismuth selenide have shown a giant SOT efficiency, which is larger than those from three-dimensional heavy metals by at least 1 order of magnitude. Transition-metal dichalcogenides such as tungsten telluride have shown a current-induced out-of-plane spin polarization, which is allowed by the reduced symmetry. In this review, we use symmetry arguments to predict and analyze SOTs in two-dimensional material-based heterostructures. We summarize the recent progress of SOT studies based on topological insulators and transition-metal dichalcogenides and show how these results are in line with the symmetry arguments. At last, we identify unsolved issues in the current studies and suggest three potential research directions in this field.
High fat diet (HFD) treated mouse is widely used as experimental animal model for hyperlipidemia and hyperglycemia study. Many factors contribute to establish animal model that meant to simulate high ...fat and glucose diet induced phenotypes. In the present study, four strains of experiment mouse treated by HFD were used to explore the impact of mouse strain on lipid profile, glucose level, and major inflammation cytokines. HFD fed Kunming and ICR mouse gained significantly higher body weight than control which was not shown by C57BL/6 and BALB/c mouse. All four strains fed by HFD has heavier liver and adipose tissue than control ones. Obvious fat droplets and enlarged adipose cells were observed in obese mouse of four strains. Additionally, obese mouse showed typical response to glucose and insulin load in OGTT and ITT. Serum TC, LDL-c, and TC/HDL-c ratio, but not TG, increased in all four strains. Major inflammatory cytokines and insulin level showed little changes in obese mouse as well (P<0.05) The present study could provide basic information for diet induced obesity developed by four commonly used experimental mouse strains.
The lean resource management and reliable interaction of massive data are important components of a low-carbon-oriented new grid. However, with a high proportion of distributed low-carbon resources ...connected to a new grid, issues such as data anomalies, data redundancy, and missing data lead to inefficient resource management and unreliable interaction, affecting the accuracy of power grid decision-making, as well as the effectiveness of emission reduction and carbon reduction. Therefore, this paper proposes a lean resource management and reliable interaction framework of a middle platform based on distributed data governance. On this basis, a distributed data governance approach for the lean resource management method of the middle platform in the low-carbon new grid is proposed, which realizes anomalous data cleaning and missing data filling. Then, a data storage and traceability method for reliable interaction is proposed, which prevents important data from being illegally tampered with in the interaction process. The simulation results demonstrate that the proposed algorithm significantly enhances efficiency, reliability, and accuracy in anomalous data cleaning and filling, as well as data traceability.
Modern crowd counting methods usually employ deep neural networks (DNN) to estimate crowd counts via density regression. Despite their significant improvements, the regression-based methods are ...incapable of providing the detection of individuals in crowds. The detection-based methods, on the other hand, have not been largely explored in recent trends of crowd counting due to the needs for expensive bounding box annotations. In this work, we instead propose a new deep detection network with only point supervision required. It can simultaneously detect the size and location of human heads and count them in crowds. We first mine useful person size information from point-level annotations and initialize the pseudo ground truth bounding boxes. An online updating scheme is introduced to refine the pseudo ground truth during training; while a locally-constrained regression loss is designed to provide additional constraints on the size of the predicted boxes in a local neighborhood. In the end, we propose a curriculum learning strategy to train the network from images of relatively accurate and easy pseudo ground truth first. Extensive experiments are conducted in both detection and counting tasks on several standard benchmarks, e.g. ShanghaiTech, UCF_CC_50, WiderFace, and TRANCOS datasets, and the results show the superiority of our method over the state-of-the-art.
DNA methylation at the C-5 position of cytosine (5mC) is one of the best-studied epigenetic modifications and plays important roles in diverse biological processes. Iterative oxidation of 5mC by the ...ten-eleven translocation (Tet) family of proteins generates 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). 5fC and 5caC are selectively recognized and excised by thymine DNA glycosylase (TDG), leading to DNA demethylation. Functional characterization of Tet proteins has been complicated by the redundancy between the three family members. Using CRISPR/Cas9 technology, we generated mouse embryonic stem cells (ESCs) deficient for all three Tet proteins (Tet triple knockout TKO). Whole-genome bisulfite sequencing (WGBS) analysis revealed that Tet-mediated DNA demethylation mainly occurs at distally located enhancers and fine-tunes the transcription of genes associated with these regions. Functional characterization of Tet TKO ESCs revealed a role for Tet proteins in regulating the two-cell embryo (2C)-like state under ESC culture conditions. In addition, Tet TKO ESCs exhibited increased telomere-sister chromatid exchange and elongated telomeres. Collectively, our study reveals a role for Tet proteins in not only DNA demethylation at enhancers but also regulating the 2C-like state and telomere homeostasis.
Daytime radiative coolers are used to pump excess heat from a target object into a cold exterior space without energy consumption. Radiative coolers have become attractive cooling options. In this ...study, a daytime radiative cooler was designed to have a selective emissive property of electromagnetic waves in the atmospheric transparency window of 8–13 μm and preserve low solar absorption for enhancing radiative cooling performance. The proposed daytime radiative cooler has a simple multilayer structure of inorganic materials, namely, Al2O3, Si3N4, and SiO2, and exhibits high emission in the 8–13 μm region. Through a particle swarm optimization method, which is based on an evolutionary algorithm, the stacking sequence and thickness of each layer were optimized to maximize emissions in the 8–13 μm region and minimize the cooling temperature. The average value of emissivity of the fabricated inorganic radiative cooler in the 8–13 μm range was 87%, and its average absorptivity in the solar spectral region (0.3–2.5 μm) was 5.2%. The fabricated inorganic radiative cooler was experimentally applied for daytime radiative cooling. The inorganic radiative cooler can reduce the temperature by up to 8.2 °C compared to the inner ambient temperature during the daytime under direct sunlight.
How the chromatin regulatory landscape in the inner cell mass cells is established from differentially packaged sperm and egg genomes during preimplantation development is unknown. Here, we develop a ...low-input DNase I sequencing (liDNase-seq) method that allows us to generate maps of DNase I-hypersensitive site (DHS) of mouse preimplantation embryos from 1-cell to morula stage. The DHS landscape is progressively established with a drastic increase at the 8-cell stage. Paternal chromatin accessibility is quickly reprogrammed after fertilization to the level similar to maternal chromatin, while imprinted genes exhibit allelic accessibility bias. We demonstrate that transcription factor Nfya contributes to zygotic genome activation and DHS formation at the 2-cell stage and that Oct4 contributes to the DHSs gained at the 8-cell stage. Our study reveals the dynamic chromatin regulatory landscape during early development and identifies key transcription factors important for DHS establishment in mammalian embryos.
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•Genome-wide mapping of DNase I hypersensitive sites in preimplantation embryos•DHSs are progressively established with a drastic increase at 8-cell embryos•Paternal chromatin accessibility is quickly reprogrammed after fertilization•Nfya and Oct4 contribute to DHSs gained in 2-cell and 8-cell stages, respectively
The DNase I-hypersensitive site mapping of mouse preimplantation embryos reveals how the chromatin regulatory landscape in the mouse embryos is established from differentially packaged sperm and egg genomes and identifies key transcription factors crucial for this process.
Genomic imprinting is an allele-specific gene expression system that is important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation. ...Although it is well known that the de novo DNA methyltransferases Dnmt3a and Dnmt3b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains unclear. Tet1 is one of the ten-eleven translocation family proteins, which have the capacity to oxidize 5-methylcytosine (5mC), specifically expressed in reprogramming PGCs. Here we report that Tet1 has a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1 knockout males and wild-Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal loss of Tet1 function. Genome-wide DNA methylation analysis of embryonic day 13.5 PGCs and sperm of Tet1 knockout mice revealed hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Analysis of the DNA methylation dynamics in reprogramming PGCs indicates that Tet1 functions to wipe out remaining methylation, including imprinted genes, at the late reprogramming stage. Furthermore, we provide evidence supporting the role of Tet1 in the erasure of paternal imprints in the female germ line. Thus, our study establishes a critical function of Tet1 in the erasure of genomic imprinting.
The cosmic curvature ( k) is a fundamental parameter for cosmology. In this paper, we propose an improved model-independent method to constrain the cosmic curvature, which is geometrically related to ...the Hubble parameter H(z) and luminosity distance DL(z). Using the currently largest H(z) sample from the well-known cosmic chronometers, as well as the luminosity distance DL(z) from the relation between the UV and X-ray luminosities of 1598 quasars and the newly compiled Pantheon sample including 1048 SNe Ia, 31 independent measurements of the cosmic curvature k(z) can be expected covering the redshift range of 0.07 < z < 2. Our estimation of k(z) is fully compatible with flat universe at the current level of observational precision. Meanwhile, we find that, for the Hubble diagram of 1598 quasars as a new type of standard candle, the spatial curvature is constrained to be k = 0.08 0.31. For the latest Pantheon sample of SNe Ia observations, we obtain k = − 0.02 0.14. Compared to other approaches aiming for model-independent estimations of spatial curvature, our analysis also achieves constraints with competitive precision. More interestingly, it is suggested that the reconstructed curvature k is negative in the high-redshift region, which is also consistent with the results from the model-dependent constraints in the literature. Such findings are confirmed by our reconstructed evolution of k(z), in the framework of a model-independent method of Gaussian processes (GP) without assuming a specific form.
A soft manipulator usually has infinite joints. The infinite DOFs of a soft manipulator make it impossible to build the mechanical model like traditional rigid manipulator. The dynamic model based on ...circular arcs assumption, proposed by previous literature, does not take torsion into consideration. The introduction of torsion to piecewise constant curvature assumption could improve accuracy for 3-D motion, but it still cannot deal with problems with normal strain and viscidity of soft material, especially when the Young's Modulus is small. In this paper, by combining the geometrically exact Cosserat rod theory and Kelvin model, a new mechanical model for a silicone rubber soft manipulator is proposed. Two vectors, curvature vector and strain vector, are used to depict the bending and torsion effect, and normal strain. Both 2-D and 3-D experiments are performed to verify the mechanical model.
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