73 research outputs found
Ferroelectricity controlled chiral spin textures and anomalous valley Hall effect in the Janus magnet-based multiferroic heterostructure
Realizing effective manipulation and explicit identification of topological
spin textures are two crucial ingredients to make them as information carrier
in spintronic devices with high storage density, high data handling speed and
low energy consumption. Electric-field manipulation of magnetism has been
achieved as a dissipationless method compared with traditional regulations.
However, the magnetization is normally insensitive to the electric field since
it does not break time-reversal symmetry directly, and distribution of
topological magnetic quasiparticles is difficult to maintain due to the drift
arising from external fluctuation, which could result in ambiguous recognition
between quasiparticles and uniform magnetic background. Here, we demonstrate
that electric polarization-driven skyrmionic and uniform ferromagnetic states
can be easily and explicitly distinguished by transverse voltage arising from
anomalous valley Hall effect in the Janus magnet-based multiferroic
heterostructure LaClBr/In2Se3. Our work provides an alternative approach for
data encoding, in which data are encoded by combing topological spin textures
with detectable electronic transport.Comment: published in 2D materials, 9, 045030 (2022
Dzyaloshinskii-Moriya interaction and magnetic skyrmions induced by curvature
Realizing sizeable Dzyaloshinskii-Moriya interaction (DMI) in intrinsic
two-dimensional (2D) magnets without any manipulation will greatly enrich
potential application of spintronics devices. The simplest and most desirable
situation should be 2D magnets with intrinsic DMI and intrinsic chiral spin
textures. Here, we propose to realize DMI by designing periodic ripple
structures with different curvatures in low-dimensional magnets and demonstrate
the concept in both one-dimensional (1D) CrBr2 and two-dimensional (2D) MnSe2
magnets by using first-principles calculations. We find that DMIs in curved
CrBr2 and MnSe2 can be efficiently controlled by varying the size of curvature
c, where c is defined as the ratio between the height h and the length l of
curved structure. Moreover, we unveil that the dependence of first-principles
calculated DMI on size of curvature c can be well described by the three-site
Fert-L\'evy model. At last, we uncover that field-free magnetic skyrmions can
be realized in curved MnSe2 by using atomistic spin model simulations based on
first-principles calculated magnetic parameters. The work will open a new
avenue for inducing DMI and chiral spin textures in simple 2D magnets via
curvature.Comment: Published on Physical Review B 106, 05442
AoBck1 and AoMkk1 Are Necessary to Maintain Cell Wall Integrity, Vegetative Growth, Conidiation, Stress Resistance, and Pathogenicity in the Nematode-Trapping Fungus Arthrobotrys oligospora
The cell wall integrity (CWI) pathway is composed of three mitogen-activated protein kinases (MAPKs), Bck1, Mkk1/2, and Slt2, and is one of the main signaling pathways for fungal pathogenesis, cell wall synthesis, and integrity maintenance. In this study, we characterized orthologs of Saccharomyces cerevisiae Bck1 and Mkk1 in the nematode-trapping (NT) fungus Arthrobotrys oligospora by multiple phenotypic comparison, and the regulation of conidiation and cell wall synthesis was analyzed using real-time PCR (RT-PCR). Both ΔAoBck1 and ΔAoMkk1 mutants showed severe defects in vegetative growth, cell nucleus number, and stress resistance. Both the mutants were unable to produce spores, and the transcription of several genes associated with sporulation and cell wall biosynthesis was markedly downregulated during the conidiation stage. Further, cell walls of the ΔAoBck1 and ΔAoMkk1 mutants were severely damaged, and the Woronin body failed to respond to cellular damage. In particular, the mutants lost the ability to produce mycelial traps for nematode predation. Taken together, AoBck1 and AoMkk1 play a conserved role in mycelial growth and development, CWI, conidiation, multi-stress tolerance, trap formation, and pathogenicity. We highlighted the role of AoBck1 and AoMkk1 in regulating the Woronin body response to cellular damage and cell nucleus development in A. oligospora
Identification of microRNAs expressed in the midgut of Aedes albopictus during dengue infection
Large and tunable magnetoresistance in van der Waals ferromagnet/semiconductor junctions
Magnetic tunnel junctions (MTJs) with conventional bulk ferromagnets separated by a nonmagnetic insulating layer are key building blocks in spintronics for magnetic sensors and memory. A radically different approach of using atomically-thin van der Waals (vdW) materials in MTJs is expected to boost their figure of merit, the tunneling magnetoresistance (TMR), while relaxing the lattice-matching requirements from the epitaxial growth and supporting high-quality integration of dissimilar materials with atomically-sharp interfaces. We report TMR up to 192% at 10 K in all-vdW Fe3GeTe2/GaSe/Fe3GeTe2 MTJs. Remarkably, instead of the usual insulating spacer, this large TMR is realized with a vdW semiconductor GaSe. Integration of semiconductors into the MTJs offers energy-band-tunability, bias dependence, magnetic proximity effects, and spin-dependent optical-selection rules. We demonstrate that not only the magnitude of the TMR is tuned by the semiconductor thickness but also the TMR sign can be reversed by varying the bias voltages, enabling modulation of highly spin-polarized carriers in vdW semiconductors
Large and tunable magnetoresistance in van der Waals Ferromagnet/Semiconductor junctions
Magnetic tunnel junctions (MTJs) with conventional bulk ferromagnets
separated by a nonmagnetic insulating layer are key building blocks in
spintronics for magnetic sensors and memory. A radically different approach of
using atomically-thin van der Waals (vdW) materials in MTJs is expected to
boost their figure of merit, the tunneling magnetoresistance (TMR), while
relaxing the lattice-matching requirements from the epitaxial growth and
supporting high-quality integration of dissimilar materials with
atomically-sharp interfaces. We report TMR up to 192% at 10 K in all-vdW
Fe3GeTe2/GaSe/Fe3GeTe2 MTJs. Remarkably, instead of the usual insulating
spacer, this large TMR is realized with a vdW semiconductor GaSe. Integration
of two-dimensional ferromagnets in semiconductor-based vdW junctions offers
gate-tunability, bias dependence, magnetic proximity effects, and
spin-dependent optical-selection rules. We demonstrate that not just the
magnitude, but also the TMR sign is tuned by the applied bias or the
semiconductor thickness, enabling modulation of highly spin-polarized carriers
in vdW semiconductors
Diagnosis of primary pulmonary T- cell/histiocyte-rich large B cell lymphoma with tissue eosinophilia via clinicopathological observation and molecular assay
Hydatid cyst fluid promotes peri-cystic fibrosis in cystic echinococcosis by suppressing miR-19 expression
SNARE Protein AoSec22 Orchestrates Mycelial Growth, Vacuole Assembly, Trap Formation, Stress Response, and Secondary Metabolism in Arthrobotrys oligospora
Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) facilitate intracellular vesicle trafficking and membrane fusion in eukaryotes and play a vital role in fungal growth, development, and pathogenicity. However, the functions of SNAREs are still largely unknown in nematode-trapping fungi. Arthrobotrys oligospora is a representative species of nematode-trapping fungi that can produce adhesive networks (traps) for nematode predation. In this study, we characterized AoSec22 in A. oligospora, a homolog of the yeast SNARE protein Sec22. Deletion of Aosec22 resulted in remarkable reductions in mycelial growth, the number of nuclei, conidia yield, and trap formation, especially for traps that failed to develop mature three-dimensional networks. Further, absence of Aosec22 impaired fatty acid utilization, autophagy, and stress tolerance; in addition, the vacuoles became small and fragmented in the hyphal cells of the ∆Aosec22 mutant, and large vacuoles failed to form. The reduced sporulation capacity correlated with the transcriptional repression of several sporulation-related genes, and the impaired accumulation of lipid droplets is in line with the transcriptional repression of several genes involved in fatty acid oxidation. Moreover, absence of Aosec22 remarkably impaired secondary metabolism, resulting in 4717 and 1230 compounds upregulated and downregulated in the ∆Aosec22 mutant, respectively. Collectively, our data highlighted that the SNARE protein AoSec22 plays a pleiotropic role in mycelial growth and development, vacuole assembly, lipid metabolism, stress response, and secondary metabolism; in particular, it is required for the proper development of traps in A. oligospora
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