Search

Abstract Achieving effective manipulation of perpendicular exchange bias effect remains an intricate endeavor, yet it stands a significance for the evolution of ultra-high capacity and energy-efficient magnetic memory and logic devices. A persistent impediment to its practical applications is the reliance on external magnetic fields during the current-induced switching of exchange bias in perpendicularly magnetized structures. This study elucidates the achievement of a full electrical manipulation of the perpendicular exchange bias in the multilayers with an ultrathin antiferromagnetic layer. Owing to the anisotropic epitaxial strain in the 2-nm-thick IrMn3 layer, the considerable exchange bias effect is clearly achieved at room temperature. Concomitantly, a specific global uncompensated magnetization manifests in the IrMn3 layer, facilitating the switching of the irreversible portion of the uncompensated magnetization. Consequently, the perpendicular exchange bias can be manipulated by only applying pulsed current, notably independent of the presence of any external magnetic fields.

Abstract Ultrastrong and deep-strong coupling are two coupling regimes rich in intriguing physical phenomena. Recently, hybrid magnonic systems have emerged as promising candidates for exploring these regimes, owing to their unique advantages in quantum engineering. However, because of the relatively weak coupling between magnons and other quasiparticles, ultrastrong coupling is predominantly realized at cryogenic temperatures, while deep-strong coupling remains to be explored. In our work, we achieve both theoretical and experimental realization of room-temperature ultrastrong magnon-magnon coupling in synthetic antiferromagnets with intrinsic asymmetry of magnetic anisotropy. Unlike most ultrastrong coupling systems, where the counter-rotating coupling strength g 2 is strictly equal to the co-rotating coupling strength g 1, our systems allow for highly tunable g 1 and g 2. This high degree of freedom also enables the realization of normalized g 1 or g 2 larger than 0.5. Particularly, our experimental findings reveal that the maximum observed g 1 is nearly identical to the bare frequency, with g 1/ω 0 = 0.963, indicating a close realization of deep-strong coupling within our hybrid magnonic systems. Our results highlight synthetic antiferromagnets as platforms for exploring unconventional ultrastrong and even deep-strong coupling regimes, facilitating the further exploration of quantum phenomena.

Abstract Recently, the altermagnetic materials with spin splitting effect (SSE), have drawn significant attention due to their potential to the flexible control of the spin polarization by the Néel vector. Here, the direct and inverse altermagnetic SSE (ASSE) in the (101)‐oriented RuO2 film with the tilted Néel vector are reported. First, the spin torque along the x‐, y‐, and z‐axis is detected from the spin torque‐induced ferromagnetic resonance (ST‐FMR), and the z‐spin torque emerges when the electric current is along the [010] direction, showing the anisotropic spin splitting of RuO2. Further, the current‐induced modulation of damping is used to quantify the damping‐like torque efficiency (ξDL) in RuO2/Py, and an anisotropic ξDL is obtained and maximized for the current along the [010] direction, which increases with the reduction of the temperature, indicating the present of ASSE. Next, by way of spin pumping measurement, the inverse altermagnetic spin splitting effect (IASSE) is studied, which also shows a crystal direction‐dependent anisotropic behavior and temperature‐dependent behavior. This work gives a comprehensive study of the direct and inverse ASSE effects in the altermagnetic RuO2, inspiring future altermagnetic materials and devices with flexible control of spin polarization.

Abstract The incorporation of randomness into stochastic computing can provide ample opportunities for applications such as simulated annealing, non‐polynomial hard problem solving, and Bayesian neuron networks. In these cases, a considerable number of random numbers with an accurate and configurable probability distribution function (PDF) are indispensable. Preferably, these random numbers are provided at the hardware level to improve speed, efficiency, and parallelism. In this paper, how spin‐orbit torque magnetic tunnel junctions (SOT‐MTJs) with high barriers are suitable candidates for the desired true random number generators is demonstrated. Not only do these SOT‐MTJs perform excellently in speed and endurance, but their randomness can also be conveniently and precisely controlled by a writing voltage, which makes them a well‐performed Bernoulli bit. By utilizing these SOT‐MTJ‐based Bernoulli bits, any PDF, including Gaussian, uniform, exponential, Chi‐square, and even arbitrarily defined distributions can be realized. These PDF‐configurable true random number generators can then promise to advance the development of stochastic computing and broaden the applications of the SOT‐MTJs.

Malignant glioma (MG) is the most common type of primary malignant brain tumors. Surgical resection of MG remains the cornerstone of therapy and the extent of resection correlates with patient survival. A limiting factor for resection, however, is the difficulty in differentiating the tumor from normal tissue during surgery. Fluorescence imaging is an emerging technique for real-time intraoperative visualization of MGs and their boundaries. However, most clinical grade neurosurgical operative microscopes with fluorescence imaging ability are hampered by low adoption rates due to high cost, limited portability, limited operation flexibility, and lack of skilled professionals with technical knowledge. To overcome the limitations, we innovatively integrated miniaturized light sources, flippable filters, and a recording camera to the surgical eye loupes to generate a wearable fluorescence eye loupe (FLoupe) device for intraoperative imaging of fluorescent MGs. Two FLoupe prototypes were constructed for imaging of Fluorescein and 5-aminolevulinic acid (5-ALA), respectively. The wearable FLoupe devices were tested on tumor-simulating phantoms and patients with MGs. Comparable results were observed against the standard neurosurgical operative microscope (PENTERO® 900) with fluorescence kits. The affordable and wearable FLoupe devices enable visualization of both color and fluorescence images with the same quality as the large and expensive stationary operative microscopes. The wearable FLoupe device allows for a greater range of movement, less obstruction, and faster/easier operation. Thus, it reduces surgery time and is more easily adapted to the surgical environment than unwieldy neurosurgical operative microscopes. Clinical and Translational Impact Statement—The affordable and wearable fluorescence imaging device developed in this study enables neurosurgeons to observe brain tumors with the same clarity and greater flexibility compared to bulky and costly operative microscopes.

Abstract The utilization of novel noncollinear antiferromagnetic materials holds great promise for the development of energy‐efficient spintronic devices. However, only a few studies have reported on the all‐electrical control of perpendicular magnetization switching using noncollinear antiferromagnets as the spin source, and the underlying mechanism behind the unconventional spin‐orbit torque (SOT) is still a topic of debate. In this work, deterministic perpendicular magnetization switching in Mn3Sn/CoTb bilayers is successfully achieved. Compared to the control samples with heavy metal as the spin source, the critical switching current density is over one order of magnitude reduced, indicating an enhanced efficiency of the out‐of‐plane charge‐to‐spin conversion in the textured Mn3Sn films. The influence of film thickness and growth temperature on the efficiency of different spin polarizations suggests potential roles of crystal quality and spin texture in spin diffusion with different spin polarization directions. These findings provide valuable insights into the crystal structure, spin‐orbit torque effects, and charge‐to‐spin conversion in Mn3Sn films, highlighting the importance of understanding interface and bulk contributions in antiferromagnetic spin transport phenomena.

Abstract Cubic materials host high crystal symmetry and hence are not expected to support anisotropy in transport phenomena. In contrast to this common expectation, here we report an anomalous anisotropy of spin current can emerge in the (001) film of Mn3Pt, a noncollinear antiferromagnetic spin source with face-centered cubic structure. Such spin current anisotropy originates from the intertwined time reversal-odd ( $${{{{{\mathscr{T}}}}}}$$ T -odd) and time reversal-even ( $${{{{{\mathscr{T}}}}}}$$ T -even) spin Hall effects. Based on symmetry analyses and experimental characterizations of the current-induced spin torques in Mn3Pt-based heterostructures, we find that the spin current generated by Mn3Pt (001) exhibits exotic dependences on the current direction for all the spin components, deviating from that in conventional cubic systems. We also demonstrate that such an anisotropic spin current can be used to realize low-power spintronic applications such as the efficient field-free switching of the perpendicular magnetizations.

Abstract Magnetization in a ferromagnetic layer could be manipulated by the spin-orbit torque whose generation commonly relies on the spin-orbit coupling from the adjacent heavy-metal layer within the bilayer. The fact that the magnetic topological insulator possesses both the ferromagnetic order with perpendicular anisotropy and inherent spin-orbit coupling inspires to realize such a torque-induced magnetization switching without forming any heterostructure with other materials. Here, only using a single layer of magnetically-doped topological insulator Cr:(Bi,Sb)2Te3, we realize a magnetization switching only by applying a large dc current. Assisted by the magnetic history, such a switching behaves nonvolatile under zero field but becomes volatile otherwise, as consistently shown by magnetoelectric transports and magneto-optical Kerr effect measurements. Static and quasistatic current are found to be equivalent for the switching. We propose that this switching may associate with the torque resulted from the spin-orbit coupling and the compositional asymmetry in the Cr-profile of the single layer.

Abstract The discovery of magnetic order in atomically-thin van der Waals materials has strengthened the alliance between spintronics and two-dimensional materials. An important use of magnetic two-dimensional materials in spintronic devices, which has not yet been demonstrated, would be for coherent spin injection via the spin-pumping effect. Here, we report spin pumping from Cr2Ge2Te6 into Pt or W and detection of the spin current by inverse spin Hall effect. The magnetization dynamics of the hybrid Cr2Ge2Te6/Pt system are measured, and a magnetic damping constant of ~ 4–10 × 10−4 is obtained for thick Cr2Ge2Te6 flakes, a record low for ferromagnetic van der Waals materials. Moreover, a high interface spin transmission efficiency (a spin mixing conductance of 2.4 × 1019/m2) is directly extracted, which is instrumental in delivering spin-related quantities such as spin angular momentum and spin-orbit torque across an interface of the van der Waals system. The low magnetic damping that promotes efficient spin current generation together with high interfacial spin transmission efficiency suggests promising applications for integrating Cr2Ge2Te6 into low-temperature two-dimensional spintronic devices as the source of coherent spin or magnon current.

Abstract The Orbital Hall effect, which originates from materials with weak spin-orbit coupling, has attracted considerable interest for spin-orbitronic applications. Here, we demonstrate the inverse effect of the orbital Hall effect and observe orbitronic terahertz emission in the Ti and Mn materials. Through spin-orbit transition in the ferromagnetic layer, the generated orbital current can be converted to charge current in the Ti and Mn layers via the inverse orbital Hall effect. Furthermore, the inserted W layer provides an additional conversion of the orbital-charge current in the Ti and Mn layers, significantly enhancing the orbitronic terahertz emission. Moreover, the orbitronic terahertz emission can be manipulated by cooperating with the inverse orbital Hall effect and the inverse spin Hall effect in the different sample configurations. Our results not only discover the physical mechanism of condensed matter physics but also pave the way for designing promising spin-orbitronic devices and terahertz emitters.

Abstract Discovering and understanding anomalous anisotropic magnetoresistance (AMR) effects are important aspects of studying the nature of modulated transport. The anisotropic transport coefficients of topological systems are often useful for mapping hidden phases and characterizing topological phase transitions and the evolution of topological electrons. Here, we report an unusual change in the AMR effect in HoPtBi. Remarkably, the AMR exhibits transitions from a quasi-twofold to fourfold symmetry and finally forms a stable rotated fourfold symmetry with increasing magnetic fields. The evolution analysis from the three-dimensional (3D) mapping experiments confirms that it is an intrinsic 3D effect. Fourier transformation analysis indicates that the superposition of C2, C4, and C6 signals with phase angle transitions leads to the novel AMR. All transitions are summarized as symmetry rotation or the inversion of peaks and valleys. By combining the features of band structures and AMR, we evaluate the possible origin of this symmetry rotation and attribute it to the topological band change. This work provides insight into the anomalous AMR effect of topological materials and is useful for understanding the evolution of topological bands in a magnetic field. We propose that other rare-earth half-Heusler alloys can potentially exhibit similar phenomena.

Abstract Manipulating spin polarization orientation is challenging but crucial for field-free spintronic devices. Although such manipulation has been demonstrated in a limited number of antiferromagnetic metal-based systems, the inevitable shunting effects from the metallic layer can reduce the overall device efficiency. In this study, we propose an antiferromagnetic insulator-based heterostructure NiO/Ta/Pt/Co/Pt for such spin polarization control without any shunting effect in the antiferromagnetic layer. We show that zero-field magnetization switching can be realized and is related to the out-of-plane component of spin polarization modulated by the NiO/Pt interface. The zero-field magnetization switching ratio can be effectively tuned by the substrates, in which the easy axis of NiO can be manipulated by the tensile or compressive strain from the substrates. Our work demonstrates that the insulating antiferromagnet based heterostructure is a promising platform to enhance the spin-orbital torque efficiency and achieve field-free magnetization switching, thus opening an avenue towards energy-efficient spintronic devices.

In-plane shear mechanical experiments of ceramic matrix mini-composites (CMMC) were realized in this paper by overcoming the difficulties of material preparation, specimen design, gripping and loading, deformation measurement, etc. The in-plane shear stress-strain responses of different matrix volume fractions were obtained based on the method. The stress-strain response of CMMC was strongly non-linear, and its elastic modulus and strength were positively correlated to the matrix volume fraction. The main factors affecting the digital image correlation (DIC) based micro-region shear deformation measurement are analyzed quantitatively, and the corresponding solutions are discussed. The DIC calculation time model is established, and the accurate estimation of DIC processing time is realized. The shear strain field evolution clearly captured the matrix crack initiation and propagation.

Abstract Deep learning models have been widely used in many supervised learning applications. However, these models suffer from overfitting due to various types of uncertainty with deteriorating performance when facing data biases, class imbalance, or noise propagation. The Information-Set Deep learning (ISDL) architectures with four variants are developed by integrating information set theory and deep learning principles to address the critical problem of the absence of robust deep learning models. There is a description of the ISDL architectures, learning algorithms, and analytic workflows. The performance of the ISDL models and standard architectures is evaluated using a noise-corrupted benchmark dataset. The experimental results show that the ISDL models can efficiently handle noise-dominated uncertainty and outperform peer architectures.

Pomegranate (Punica granatum L.), with its abundant phenolic substances and strong antioxidant activity, holds significant research and utilization potential across various organs. However, there have been few studies on the phenolic content and antioxidant activity of different parts of pomegranate, especially the placenta. This study investigated the phenolic content and antioxidant activity of fruits, flowers, and leaves of two pomegranate varieties, ‘Tunisia’ and ‘Qingpi’, throughout their growth and development. Results indicated significant variations in phenolic content among different organs, with petals exhibiting the highest total polyphenol content (TPC, 49.40 mg GAE/g FW) and total anthocyanin content (TMAC, 1938.54 nmol/g FW). Placenta contained the highest levels of total flavonoids (TFC, 173.58 mg RE/g FW) and punicalagin (109.30 mg/g FW). The peel had the highest content of total flavanols (TFAC, 19.42 mg CE/g FW). Over the course of pomegranate development, total polyphenols, total flavonoids, total flavanols, punicalagin, and antioxidant activity declined in different organs. Antioxidant activity followed the order: fruit > flower > leaf, with the placenta exhibiting the highest antioxidant activity among fruits. Antioxidant activity showed a significant positive correlation with total polyphenols (R2 = 0.77-1.00), total flavonoids (R2 = 0.71-0.99, except tegmens), and punicalagin (R2 = 0.71-1.00). This study provides a comparative analysis of the phenolic content and antioxidant activity in different organs of pomegranate, highlighting the placenta as the primary source of punicalagin. This study provides a theoretical basis for the development and utilization of pomegranate phenolic compounds.

Soil conservation is necessary to achieve a sustainable world because soils play a crucial role in the Earth's system. At the same time, the applicable and precise methods are vital to obtaining credible data in soil studies. A collection of 10 articles have been organized to focus on the new technologies regarding soil conservation and eco-sustainability and the results related to the novel approaches. The articles put effort into the innovative works of field investigations, field experiments, model experiments, and numerical simulations. Pivotal questions baffling soil scientists have been clarified and solved, and many valuable insights have been aroused.

Abstract Exploration of exotic transport behavior for quantum materials is of great interest and importance for revealing exotic orders to bring new physics. In this work, we report the observation of unconventional prominent planar Hall effect (PHE) and planar anisotropic magnetoresistivity (PAMR) in strange kagome metal KV3Sb5. The PHE and PAMR, which are driven by an in-plane magnetic field and display sharp difference from other Hall effects driven by an out-of-plane magnetic field or magnetization, exhibit exotic higher-order oscillations in sharp contrast to those following empirical rule only allowing two-fold symmetrical oscillations. These higher-order oscillations exhibit strong field and temperature dependence and vanish around charge density wave (CDW) transition. The unique transport properties suggest a significant interplay of the lattice, magnetic and electronic structure in KV3Sb5. This interplay can couple the hidden anisotropy and transport electrons leading to the unconventional PHE and PAMR in contrast to other materials.

Spin–orbit torques (SOTs) provide an efficient way to electrically manipulate the magnetic order in spintronic devices. Compared with conventional ferromagnetic materials, ferrimagnetic materials have the advantages of antiferromagnetically coupled sublattices and induced ultrafast spin dynamics. In this paper, we study the current-induced magnetization switching in the ferrimagnetic Ta/GdFeCo/MgO system. Robust SOT-induced magnetization switching can be achieved at the magnetic compensation temperature point of around 70 K, where the magnetization is nearly zero and the coercivity can reach almost 3 T. The temperature dependence of the SOT efficiency is quantified by the second harmonic method, and the enhanced SOT efficiency near the magnetic compensation temperature is attributed to the negative exchange coupling between the two sublattices of CoFe and Gd. This work demonstrates the SOT switching of the nearly compensated ferrimagnet, with great potential for future magnetic interaction-free and ultrafast ferrimagnetic applications.

Abstract Magnetic skyrmions are topologically protected noncollinear spin textures, which are regarded as promising information carriers for next‐generation spintronic devices due to their small size and the low current density needed to drive their motion. Stability of skyrmions in zero external magnetic field is important for promoting fundamental studies and device applications. A few zero‐field skyrmion‐hosting materials have been developed, but none of them have been successfully integrated into a magnetic tunnel junction (MTJ), a crucial device for converting skyrmion information into an electrical signal. Here, a zero‐field exchange‐biased skyrmion material is developed and incorporated into an MTJ device. An Ir layer is inserted between the antiferromagnetic and ferromagnetic layers, which plays a crucial role in prohibiting interlayer diffusion under thermal annealing, resulting in simultaneous enhancement of exchange bias and thermal stability. The smallest zero‐field skyrmions have a size of 100 nm at room temperature. The zero‐field skyrmion material is then integrated into a perpendicularly magnetized MTJ, leading to the first demonstration of zero‐field skyrmions in an MTJ, which is an important step toward developing skyrmion‐based spintronic devices.

Abstract Magnetic skyrmions are promising information carriers for dense and energy‐efficient information storage owing to their small size, low driving‐current density, and topological stability. Electrical detection of skyrmions is a crucial requirement to drive skyrmion devices toward applications. The use of a magnetic tunnel junction (MTJ) is commonly suggested for this purpose as MTJs are key spintronic devices for large‐scale commercialization that can convert magnetic textures into electrical signals. To date, however, it has been challenging to realize skyrmions in MTJs due to incompatibility between standard skyrmion materials and highly efficient MTJ electrodes. Here, a material stack combining magnetic multilayers, which host 100 nm scale skyrmions, with a perpendicularly magnetized MTJ, is reported. The devices are designed so that the skyrmions in the multilayer are imprinted into the MTJ's free layer via magnetostatic interactions. The electrical response of a single skyrmion is successfully identified by employing simultaneous imaging of the magnetic texture and the electrical measurement of the MTJ resistance. The results are an important step toward all‐electrical detection of skyrmions.

Glycans are one of the fundamental biopolymers encountered in living systems. Compared to polynucleotide and polypeptide biosynthesis, polysaccharide biosynthesis is a uniquely combinatorial process to which interdependent enzymes with seemingly broad specificities contribute. The resulting intracellular cell surface, and secreted glycans play key roles in health and disease, from embryogenesis to cancer progression. The study and modulation of glycans in cell and organismal biology is aided by small molecule inhibitors of the enzymes involved in glycan biosynthesis. In this review, we survey the arsenal of currently available inhibitors, focusing on agents which have been independently validated in diverse systems. We highlight the utility of these inhibitors and drawbacks to their use, emphasizing the need for innovation for basic research as well as for therapeutic applications.

Abstract Missing values are a major issue in quantitative proteomics analysis. While many methods have been developed for imputing missing values in high-throughput proteomics data, a comparative assessment of imputation accuracy remains inconclusive, mainly because mechanisms contributing to true missing values are complex and existing evaluation methodologies are imperfect. Moreover, few studies have provided an outlook of future methodological development. We first re-evaluate the performance of eight representative methods targeting three typical missing mechanisms. These methods are compared on both simulated and masked missing values embedded within real proteomics datasets, and performance is evaluated using three quantitative measures. We then introduce fused regularization matrix factorization, a low-rank global matrix factorization framework, capable of integrating local similarity derived from additional data types. We also explore a biologically-inspired latent variable modeling strategy—convex analysis of mixtures—for missing value imputation and present preliminary experimental results. While some winners emerged from our comparative assessment, the evaluation is intrinsically imperfect because performance is evaluated indirectly on artificial missing or masked values not authentic missing values. Nevertheless, we show that our fused regularization matrix factorization provides a novel incorporation of external and local information, and the exploratory implementation of convex analysis of mixtures presents a biologically plausible new approach.

It remains challenging to integrate topological insulators (TI) with magnetic tunnel junctions (MTJ) for spintronics applications. Here, the authors achieve a large tunneling magnetoresistance ratio and a low switching current density in a TI-MTJ device at room temperature, very promising for TI-driven magnetic memory.

Emerging in‐memory computing (IMC) technology promises to tackle the memory wall bottleneck in modern systems. Promoted as a promising building block, nonvolatile spin–orbit torque (SOT) memory devices with sub‐ns and sub‐pJ processing capabilities are thereby extensively pursued. Herein, a new type of domain wall device is experimentally presented with multistates driven by nonvolatile SOT and Dzyaloshinskii–Moriya interaction, enabling time and energy‐efficient IMC with a full adder (FA) implementation based on magnetic tunnel junctions. Complementary micromagnetic and device–circuit cosimulation results show that the write/read latency of the proposed FA can be shortened to 1.25 ns/0.22 ns with an averaged writing energy of 8.41 fJ bit−1, and the overall dynamic power is 26.25 μW, which is 4.43–51.96 times lower than state‐of‐the‐art alternatives. Moreover, the developed architecture can perform all 16 Boolean logic functions, warranting an extensive arithmetic operation. The experimental, micromagnetic, and circuit‐level simulation results show great potential in both fundamental research and new trajectories in technology development for nonvolatile in‐memory computing applications.

We report the experimental observation of the spin-wave moiré edge and cavity modes using Brillouin light scattering spectromicroscopy in a nanostructured magnetic moiré lattice consisting of two twisted triangle antidot lattices based on an yttrium iron garnet thin film. Spin-wave moiré edge modes are detected at an optimal twist angle and with a selective excitation frequency. At a given twist angle, the magnetic field acts as an additional degree of freedom for tuning the chiral behavior of the magnon edge modes. Micromagnetic simulations indicate that the edge modes emerge within the original magnonic band gap and at the intersection between a mini flatband and a propagation magnon branch. Our theoretical estimate for the Berry curvature of the magnon-magnon coupling suggests a nontrivial topology for the chiral edge modes and confirms the key role played by the dipolar interaction. Our findings shed light on the topological nature of the magnon edge mode for emergent moiré magnonics.

Abstract Among multiple subtypes of tissue or cell, subtype-specific differentially-expressed genes (SDEGs) are defined as being most-upregulated in only one subtype but not in any other. Detecting SDEGs plays a critical role in the molecular characterization and deconvolution of multicellular complex tissues. Classic differential analysis assumes a null hypothesis whose test statistic is not subtype-specific, thus can produce a high false positive rate and/or lower detection power. Here we first introduce a One-Versus-Everyone Fold Change (OVE-FC) test for detecting SDEGs. We then propose a scaled test statistic (OVE-sFC) for assessing the statistical significance of SDEGs that applies a mixture null distribution model and a tailored permutation test. The OVE-FC/sFC test was validated on both type 1 error rate and detection power using extensive simulation data sets generated from real gene expression profiles of purified subtype samples. The OVE-FC/sFC test was then applied to two benchmark gene expression data sets of purified subtype samples and detected many known or previously unknown SDEGs. Subsequent supervised deconvolution results on synthesized bulk expression data, obtained using the SDEGs detected from the independent purified expression data by the OVE-FC/sFC test, showed superior performance in deconvolution accuracy when compared with popular peer methods.

Antiferromagnetic materials are potentially useful for spintronic applications. Here, the authors report high thermoelectric power value of 390 μV/K Seebeck coefficient in IrMn-based half magnetic tunnel junctions at room temperature.

Skyrmions are objects with whirled magnetization protected by their topology that can be created by different means, however, without control of their position. Here, the authors present a method exploiting x-rays to create skyrmions at the beam position allowing for creation of artificial skyrmion lattices.

Accurate forecasting of droughts can effectively reduce the risk of drought. We propose a hybrid model based on complementary ensemble empirical mode decomposition (CEEMD) and long short-term memory (LSTM) to improve drought prediction accuracy. Taking the Xinjiang Uygur Autonomous Region as an example, the prediction accuracy of the LSTM and CEEMD-LSTM models for the standardized precipitation index (SPI) on multiple timescales was compared and analyzed. Multiple evaluation metrics were used in the comparison of the models, such as the Nash–Sutcliffe efficiency (NSE). The results show that (1) with increasing timescale, the prediction accuracy of the LSTM and CEEMD-LSTM models gradually improves, and both reach their highest accuracy at the 24-month timescale; (2) the CEEMD can effectively stabilize the time-series, and the prediction accuracy of the hybrid model is higher than that of the single model at each timescale; and (3) the NSE values for the hybrid CEEMD-LSTM model at SPI24 were 0.895, 0.930, 0.908, and 0.852 for Fuhai, Kuerle, Yutian, and Hami station, respectively. This indicates the applicability of the hybrid model in the forecasting of drought.

We report a current-induced four-state magnetization reversal under zero magnetic field in a wedged Ta/MgO/CoFeB/MgO heterostructure with a perpendicular magnetic anisotropy. Anomalous Hall effect and magneto-optical Kerr effect microscopy measurements were performed to demonstrate that the field-free multi-level reversal is jointly determined by the spin–orbit torque effective field that originates from the lack of the lateral inversion symmetry in the wedged stacking structure and the current-induced Oersted field. Moreover, the creation of robust intermediate Hall resistance states in the multi-state switching strongly depends on the current-induced Joule heating. Our results provide a route for the field-free multi-level state reversal, which is significant for fabricating the non-volatile and energy-efficient multi-level memories or artificial neuron devices.

AbstractDuring vertebrate central nervous system development, most oligodendrocyte progenitor cells (OPCs) are specified in the ventral spinal cord and must migrate throughout the neural tube until they become evenly distributed, occupying non-overlapping domains. While this process of developmental OPC migration is well characterized, the nature of the molecular mediators that govern it remain largely unknown. Here, using zebrafish as a model, we demonstrate that Met signaling is required for initial developmental migration of OPCs, and, using cell-specific knock-down of Met signaling, show that Met acts cell-autonomously in OPCs. Taken together, these findings demonstrate in vivo

The spin–orbit torques (SOTs) in the heavy metal (HM)/ferromagnetic metal (FM) structure hold promise for next-generation low-power and high-density spintronic memory and logic applications. For the SOT switching of a perpendicular magnetization, an external magnetic field is inevitable for breaking the mirror symmetry, which is not practical for high-density nanoelectronics applications. In this work, we study the current-induced field-free SOT switching and SOT perpendicular effective field (Hzeff) in a variety of laterally asymmetric multilayers, where the asymmetry is introduced by growing the FM layer in a wedge shape. We show that the design of structural asymmetry by wedging the FM layer is a universal scheme for realizing field-free SOT switching. Moreover, by comparing the FM layer thickness dependence of (Hzeff) in different samples, we show that the efficiency (β =Hzeff/J, J is the current density) is sensitive to the HM/FM interface and the FM layer thickness. The sign of β for thin FM thicknesses is related to the spin Hall angle (θSH) of the HM layer attached to the FM layer. β changes its sign with the thickness of the FM layer increasing, which may be caused by the thickness dependence of the work function of FM. These results show the possibility of engineering the deterministic field-free switching by combining the symmetry breaking and the materials design of the HM/FM interface.

Abstract Background Genome-wide DNA copy number changes are the hallmark events in the initiation and progression of cancers. Quantitative analysis of somatic copy number alterations (CNAs) has broad applications in cancer research. With the increasing capacity of high-throughput sequencing technologies, fast and efficient segmentation algorithms are required when characterizing high density CNAs data. Results A fast and informative segmentation algorithm, DBS (Deviation Binary Segmentation), is developed and discussed. The DBS method is based on the least absolute error principles and is inspired by the segmentation method rooted in the circular binary segmentation procedure. DBS uses point-by-point model calculation to ensure the accuracy of segmentation and combines a binary search algorithm with heuristics derived from the Central Limit Theorem. The DBS algorithm is very efficient requiring a computational complexity of O(n*log n), and is faster than its predecessors. Moreover, DBS measures the change-point amplitude of mean values of two adjacent segments at a breakpoint, where the significant degree of change-point amplitude is determined by the weighted average deviation at breakpoints. Accordingly, using the constructed binary tree of significant degree, DBS informs whether the results of segmentation are over- or under-segmented. Conclusion DBS is implemented in a platform-independent and open-source Java application (ToolSeg), including a graphical user interface and simulation data generation, as well as various segmentation methods in the native Java language.

The spin-orbit torque (SOT) induced magnetic switching makes metal/magnetic insulators bilayers preferred in the energy efficient spintronic applications. Here the authors show SOT switching in W/TmIG bilayers and reveal the dimension crossover of SOT as a function of TmIG thickness.

All 16 Boolean logic functions in a single Ta/CoFeB/MgO device with perpendicular magnetic anisotropy were experimentally demonstrated based on the spin–orbit torque (SOT) effect. Furthermore, by combining with the voltage-controlled magnetic anisotropy (VCMA) effect, a novel SOT-MTJ (magnetic tunnel junction) prototype device with the assistance of the VCMA effect was further designed to perform magnetic field-independent logic operations. The numerical simulations were carried out, demonstrating the feasibility to realize all 16 Boolean logic functions in a single three-terminal device by applying the bias voltage and current injection as input variables. This approach provides a potential way toward the application of energy efficient spin-based logic, which is beyond the current von Neumann computing architecture.

Prostate cancer (PCa) is a destructive malignancy with a bad prognosis. LncRNA VPS9D1-AS1 has recently been delineated as an oncogene in some kinds of tumor, whereas, the function of VPS9D1-AS1 in PCa remains to be clarified. In this study, we researched its underlying role in PCa. The expression of VPS9D1-AS1 was conspicuously upregulated in PCa tissues and cells. And absence of VPS9D1-AS1 inhibited cell proliferation, migration and invasion, and promoted cell apoptosis in PCa. In addition, VPS9D1-AS1 overexpression led to opposite results. Furthermore, VPS9D1-AS1/MEF2D could sponge with miR-4739. VPS9D1-AS1/MEF2D and miR-4739 were inversely correlated in tumor cells. And the expression of miR-4739 is markedly downregulated in PCa, meanwhile, that of MEF2D exhibited the opposite tendency. However, MEF2D was positively regulated by VPS9D1-AS1. Moreover, MEF2D upregulation offset the suppressive effects of VPS9D1-AS1 deficiency on cell proliferation, migration and invasion in PCa. Additionally, ZEB1 contained the binding sites of VPS9D1-AS1 promoter, and there existed positive relation between them. Taken together, above results illustrated that ZEB1 activated-VPS9D1-AS1 promotes the tumorigenesis and progression of PCa by sponging miR-4739 to upregulate MEF2D, which offering a new useful reference for studying the development process of PCa.

Spin-polarized carriers could show an extra Hall component when moving through certain real-space topological spin textures. Here, He et al. report an exchange bias experienced by the topological spin textures living at the interface between a topological insulator and an adjacent antiferromagnet, suggesting a chiral spin texture is induced.

Summary: Down syndrome (DS) is a genetic disorder that causes cognitive impairment. The staggering effects associated with an extra copy of human chromosome 21 (HSA21) complicates mechanistic understanding of DS pathophysiology. We examined the neuron-astrocyte interplay in a fully recapitulated HSA21 trisomy cellular model differentiated from DS-patient-derived induced pluripotent stem cells (iPSCs). By combining calcium imaging with genetic approaches, we discovered the functional defects of DS astroglia and their effects on neuronal excitability. Compared with control isogenic astroglia, DS astroglia exhibited more-frequent spontaneous calcium fluctuations, which reduced the excitability of co-cultured neurons. Furthermore, suppressed neuronal activity could be rescued by abolishing astrocytic spontaneous calcium activity either chemically by blocking adenosine-mediated signaling or genetically by knockdown of inositol triphosphate (IP3) receptors or S100B, a calcium binding protein coded on HSA21. Our results suggest a mechanism by which DS alters the function of astrocytes, which subsequently disturbs neuronal excitability. : To understand how Down syndrome (DS) affects neural networks, Mizuno et al. used a DS-patient-derived stem cell model and calcium imaging to investigate the functional defects of DS astrocytes and their effects on neuronal excitability. Their study reveals that DS astroglia exhibited more frequent spontaneous calcium fluctuations, which impair neuronal excitability. Keywords: Down syndrome, astrocytes, astrocyte-neuron interaction, human IPSCs, calcium imaging, S100B

Prostate carcinoma may develop into metastatic castration-resistant prostate carcinoma (mCRPC) after endocrine therapy. Exosomal microRNAs play an important role in the regulation of tumor microenvironment. Our study aimed to investigate the effect of exosomal miR-26a on tumor phenotype of prostate carcinoma. Low-grade prostate carcinoma cell line (LNCAP) and mCRPC cell line (PC-3) were treated as experimental subjects according to their miR-26a expressions. Wound healing, transwell and colony-forming unit assays were performed after miR-26a mimic/inhibitor transfection. Then, exosomes were isolated from LNCAP and PC-3 cells, and the levels of exosomal miR-26a were determined. After co-culture of LNCAP (PC-3) cells with PC-3 (LNCAP) exosomes, changes in malignant behaviors were measured. Moreover, LNCAP/PC-3 exosomes were injected into xenograft tumor mice to determine effects of the exosomes on tumorigenicity of LNCAP and PC-3 cells. MiR-26a showed a potently inhibitory effect on cell proliferation, migration and invasion of LNCAP and PC-3 cells. LNCAP exosomes had a higher miR-26a level, compared with PC-3 exosomes. Overexpression of miR-26a attenuated the enhanced malignant behavior of LNCAP cells induced by PC-3 exosomes, and miR-26a inhibition could reverse the inhibitory effects of LNCAP exosomes on PC-3 cells. Exosomal miR-26a could significantly alter the expressions of epithelial-mesenchymal transition (EMT)-related factors. Moreover, LNCAP exosomes suppressed the tumorigenicity of PC-3 cells, while PC-3 exosomes could promote the tumorigenicity of LNCAP cells. Our data suggest that exosomal miR-26a derived from prostate carcinoma cells had a suppressive effect on the metastasis and tumor growth of prostate carcinoma.

Lengthy use of general anesthetics (GAs) causes neurobehavioral deficits in the developing brain, which has raised significant clinical concerns such that the United States Food and Drug Administration (FDA) is warning on the use of GAs in children younger than 3 years. However, the molecular and cellular mechanisms for GAs-induced neurotoxicity remain largely unknown. Here, we report that sevoflurane (Sevo), a commonly used GA in pediatrics, caused compromised astrocyte morphogenesis spatiotemporally correlated to synaptic overgrowth, with reduced synaptic function in developing cortex in a regional-, exposure-length-, and age-specific manner. Sevo disrupted astrocyte Ca2+ homeostasis both acutely and chronically, which led to the down-regulation of Ezrin, an actin-binding membrane-bound protein, which we found was critically involved in astrocyte morphogenesis in vivo. Importantly, overexpression of astrocyte Ezrin rescued astrocytic and neuronal dysfunctions and fully corrected deficits in social behaviors in developing mice with lengthy Sevo exposure. Our data uncover that, in addition to neurons, astrocytes may represent important targets for GAs to exert toxic effects and that astrocyte morphological integrity is crucial for synaptogenesis and neurological behaviors.

Abstract We investigated the influence of genetic variants on atherosclerosis using whole exome sequencing in cases and controls from the autopsy study “Pathobiological Determinants of Atherosclerosis in Youth (PDAY)”. We identified a PDAY case group with the highest total amounts of raised lesions (n = 359) for comparisons with a control group with no detectable raised lesions (n = 626). In addition to the standard exome capture, we included genome-wide proximal promoter regions that contain sequences that regulate gene expression. Our statistical analyses included single variant analysis for common variants (MAF > 0.01) and rare variant analysis for low frequency and rare variants (MAF

In order to enhance the ignition ability and reliability of traditional electronic initiators, a novel electronic initiator has been designed to integrate with a nanothermite multilayer film and an electrode plug. The Al/CuOx nanothermite multilayer film with different thickness is deposited on the surface of the electrode plug by magnetron sputtering which uses Pt–W wire as electronic resistance. The exothermicity of Al/CuOx nanothermite multilayer film is so favourable that the ignition ability of electronic initiator is significantly improved. The full firing-voltage sensitivity of the electronic initiator is 10.8 V. The thickness of Al/CuOx multilayer film has negligible effects on the ignition time and ignition energy, but leads to great impacts on the function time, the maximum length of combustion flame and ignition ability. The electrical ignition experiments have exhibited outstanding ignition ability, since the electronic initiator can easily fire the insensitive ignition composition of boron-potassium nitrate (B-KNO3) tablet in a gap of 20.35 mm. It proves that this novel proposal of remoulding the traditional electronic ignition devices will distinctly improve the ignition ability and reliability of electronic initiator.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

We study the impact of Mg insertion layer at the CoFeB|MgO interface on the domain wall depinning field and motion as well as other magnetic properties in a perpendicular magnetized Ta/CoFeB/Mg(wedged)/MgO structure. With the increase of the Mg layer from 0.4 nm to 0.8 nm, the field-induced domain wall moving velocity increases while the depinning field decreases. The minimum depinning field of around 10 Oe for as-grown sample and 7 Oe for annealed sample is found with a 0.8 nm Mg insertion layer, which is 2 times lower than the ones reported before. Further increase of the Mg layer leads to a lower velocity and higher depinning field. Similar phenomena happens to the magnetic properties such as the saturation magnetization and perpendicular magnetic anisotropy. Both for as-grown and annealed samples, the tendency is similar. This may be explained by the oxidation and crystallinity manipulation of the CoFeB|MgO interface. These results show an ultra-low depinning field in the Ta/CoFeB/MgO system as well as a possible way for controlling the depinning field.

Recent discoveries that astrocytes exert proactive regulatory effects on neural information processing and that they are deeply involved in normal brain development and disease pathology have stimulated broad interest in understanding astrocyte functional roles in brain circuit. Measuring astrocyte functional status is now technically feasible, due to recent advances in modern microscopy and ultrasensitive cell-type specific genetically encoded Ca2+ indicators for chronic imaging. However, there is a big gap between the capability of generating large dataset via calcium imaging and the availability of sophisticated analytical tools for decoding the astrocyte function. Current practice is essentially manual, which not only limits analysis throughput but also risks introducing bias and missing important information latent in complex, dynamic big data. Here, we report a suite of computational tools, called Functional AStrocyte Phenotyping (FASP), for automatically quantifying the functional status of astrocytes. Considering the complex nature of Ca2+ signaling in astrocytes and low signal to noise ratio, FASP is designed with data-driven and probabilistic principles, to flexibly account for various patterns and to perform robustly with noisy data. In particular, FASP explicitly models signal propagation, which rules out the applicability of tools designed for other types of data. We demonstrate the effectiveness of FASP using extensive synthetic and real data sets. The findings by FASP were verified by manual inspection. FASP also detected signals that were missed by purely manual analysis but could be confirmed by more careful manual examination under the guidance of automatic analysis. All algorithms and the analysis pipeline are packaged into a plugin for Fiji (ImageJ), with the source code freely available online at https://github.com/VTcbil/FASP.

Intramyocellular (IMCL), extramyocellular lipid (EMCL), and vitamin D deficiency are associated with muscle metabolic dysfunction. This study compared the change in [IMCL]:[EMCL] following the combined treatment of vitamin D and aerobic training (DAT) compared with vitamin D (D), aerobic training (AT), and control (CTL). Male and female subjects aged 60−80 years with a BMI ranging from 18.5−34.9 and vitamin D status of ≤32 ng/mL (25(OH)D) were recruited to randomized, prospective clinical trial double-blinded for supplement with a 2 × 2 factorial design. Cholecalciferol (Vitamin D3) (10,000 IU × 5 days/week) or placebo was provided for 13 weeks and treadmill aerobic training during week 13. Gastrocnemius IMCL and EMCL were measured with magnetic resonance spectroscopy (MRS) and MRI. Hybrid near-infrared diffuse correlation spectroscopy measured hemodynamics. Group differences in IMCL were observed when controlling for baseline IMCL (p = 0.049). DAT was the only group to reduce IMCL from baseline, while a mean increase was observed in all other groups combined (p = 0.008). IMCL reduction and the corresponding increase in rVO2 at study end (p = 0.011) were unique to DAT. Vitamin D, when combined with exercise, may potentiate the metabolic benefits of exercise by reducing IMCL and increasing tissue-level VO2 in healthy, older adults.

Magnetic skyrmions are topologically protected spin textures that exhibit many fascinating features. As compared to the well-studied cryogenic Bloch skyrmions in bulk materials, we focus on the room-temperature Néel skyrmions in thin-film systems with an interfacial broken inversion symmetry in this article. Specifically, we show the stabilization, the creation, and the implementation of Néel skyrmions that are enabled by the electrical current-induced spin-orbit torques. Towards the nanoscale Néel skyrmions, we further discuss the challenges from both material optimization and imaging characterization perspectives.

We studied the thermal stability of perpendicular magnetic anisotropy (PMA) in Ta/Mo/CoFeB/MgO/Ta films with and without inserted Mo layers. In the absence of a Mo layer, the films show PMA at annealing temperatures below 300 °C. On the other hand, the insertion of a Mo layer preserves PMA at annealing temperatures of up to 500 °C; however, a higher annealing temperature leads to the collapse of PMA. X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) were used to study the microstructure of the films to understand the deterioration of PMA. The XPS results show that the segregation of Ta is partly suppressed by inserting a Mo layer. Once inserted, Mo does not remain at the interface of Ta and CoFeB but migrates to the surface of the films. The HRTEM results show that the crystallization of the MgO (001) texture is improved owing to the higher annealing temperature of the Mo inserted sample. A smooth and clear CoFeB/MgO interface is evident. The inserted Mo layer not only helps to obtain sharper and smoother interfaces but also contributes to the crystallization after the higher annealing temperature of films.