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Mn3Sn is an anomalous Hall effect (AHE) antiferromagnet that exhibits the hysteretic AHE in antiferromagnetic (AFM) phase at room temperature. We report that whisker Mn3Sn crystals grown by the flux method exhibit a non-hysteretic AHE at mid-to-low temperatures when the whisker Mn3Sn is surrounded by a thin layer of ferromagnetic Mn2−xSn. These crystals exhibit a hysteretic AHE above 275 K due to the spin alignment of the inverse triangular lattice, which is similar to other crystals. However, upon cooling the crystal, it exhibits a non-hysteretic AHE with a spiral AFM spin structure at 100–200 K. We concluded that the non-hysteretic AHE is induced at the interface of Mn2−xSn/Mn3Sn. We believe that the scalar-spin chirality in the spiral AFM phase of Mn3Sn, modulated by Mn2−xSn through the magnetic proximity effect, produces the AHE. This discovery opens a new avenue for tailoring the AHE by magnetic layers. [ABSTRACT FROM AUTHOR]

Generally, in vertebrates, the first step toward fertilization is the ovulation of mature oocytes, followed by their binding to sperm cells outside of the ovary. Exceptionally, the oocytes of poeciliid fish are fertilized by sperm cells within the follicle, and the developmental embryo is subsequently released into the ovarian lumen before delivery. In the present study, we aimed to identify the factor(s) responsible for intrafollicular fertilization in a viviparous teleost species, Poecilia reticulata (guppy). Sperm tracking analysis in this regard indicated that in this species, sperm cells reached immature oocytes including the germinal vesicle, and the insemination assay indicated that the immature oocytes robustly adhered to the sperm cells; similar binding was not observed in Danio rerio (zebrafish) and Oryzias latipes (medaka). We also identified the Ly6/uPAR protein bouncer as the factor responsible for the observed sperm binding activity of the immature oocytes in this species. The recombinant bouncer peptide acted as an inhibitory decoy for the sperm–oocyte binding in guppy. On the other hand, ectopic expression of guppy bouncer in zebrafish oocytes resulted in interspecific sperm–oocyte binding. These results argue that bouncer is responsible for sperm–immature oocyte binding. Our findings highlight the unique reproductive strategies of guppy fish and enhance our understanding of the diverse reproductive mechanisms in vertebrates. [ABSTRACT FROM AUTHOR]

The scanning electron microscope (SEM) is a powerful tool for analyzing the surface of various specimens. SEM observation at low voltage, which is typically lower than the 1 kV range, is very effective for obtaining surface information of specimens. However, at the low voltage range, resolution is restricted by the brightness and energy spread of electron sources. Therefore, to improve the resolution, a bright and monochromatic electron source is indispensable. In this work, we focused on an electron gun with a negative electron affinity photocathode using p-type GaAs and Cs–O adsorbates. The resolution of a prototype SEM was improved by approximately 16% compared with a SEM using a conventional Schottky emission (SE)-type emitter at the acceleration voltage of 1 kV. In addition, results showed that the measured brightness was as high as an SE-type emitter (∼107 A/m2/sr/V) and the estimated energy spread was less than 0.2 eV, which was narrower than that of a cold field emission-type emitter. [ABSTRACT FROM AUTHOR]

CD8+ T cells play a central role in antitumor immune responses. Epigenetic gene regulation is essential to acquire the effector function of CD8+ T cells. However, the role of Utx, a demethylase of histone H3K27, in antitumor immunity remains unclear. In this study, we examined the roles of Utx in effector CD8+ T‐cell differentiation and the antitumor immune response. In a murine tumor‐bearing model, an increased tumor size and decreased survival rate were observed in T‐cell‐specific Utx KO (Utx KO) mice compared with wild‐type (WT) mice. The number of CD8+ T cells in tumor‐infiltrating lymphocytes (TILs) was significantly decreased in Utx KO mice. We found that the acquisition of effector function was delayed and attenuated in Utx KO CD8+ T cells. RNA sequencing revealed that the expression of effector signature genes was decreased in Utx KO effector CD8+ T cells, while the expression of naïve or memory signature genes was increased. Furthermore, the expression of Cxcr3, which is required for the migration of effector CD8+ T cells to tumor sites, was substantially decreased in Utx KO CD8+ T cells. These findings suggest that Utx promotes CD8+ T‐cell‐dependent antitumor immune responses partially through epigenetic regulation of the effector function. [ABSTRACT FROM AUTHOR]

In this study, we developed a one-step method for fabricating hydrophobic surfaces on copper (Cu) substrates. Cuprous oxide (Cu2O) with low free energy was successfully formed after low-fluence laser direct irradiation. The formation of Cu2O enhanced the hydrophobicity of the Cu substrate surface, and the contact angle linearly increased with the proportion of Cu2O. The Cu2O fabricated by low-fluence laser treatment showed the same crystal plane orientation as the pristine Cu substrate, implying an epitaxial growth of Cu2O on a Cu substrate. [ABSTRACT FROM AUTHOR]

Ultrafast phenomena in gold nanotriangles (AuNTs) were investigated using a transient electron energy-loss spectroscopy (TEELS) technique under irradiation from a 150-fs pulse laser with a wavelength of 780 nm. This investigation was conducted using a time-resolved transmission electron microscopy method that was developed to measure the dynamics of nanomaterials. Enhancement of the intensity and energy-width broadening of the energy loss were observed at the EEL peaks associated with surface and bulk plasmons on the AuNTs. The TEELS measurement revealed two decay processes of 7.8 ps and longer than 100 ps that compensate for relaxation times of excited surface plasmons using transient absorption spectroscopy. The results show that the bulk and surface plasmons have the same time evolution, i.e., that the excited electrons on the surface and in the bulk have the same relaxation processes in both electron–phonon and phonon–phonon interactions. The time evolution of electronic and lattice temperatures was also estimated based on the measured relaxation time using a two-temperature model, which revealed the volume expansion of the AuNTs and clarified the energy shifts of plasmons. Details of excited electrons in nanoparticles investigated via plasmon energy loss are expected to facilitate improvement in the performance for energy harvesting of photons in nanostructure-controlled materials. [ABSTRACT FROM AUTHOR]

Theoretical studies have predicted that interactions between magnetic skyrmions and antiskyrmions give rise to various properties, such as unique arrangements, pair annihilation, topological transformation, and rectilinear and trochoidal motions that do not appear in only skyrmions or antiskyrmions. Recently, experimental studies have discovered that a Heusler material with the anisotropic Dzyaloshinskii–Moriya interaction shows a coexisting phase at 268 K and in-plane magnetic field-induced topological transformation of elliptical skyrmions and square-shaped antiskyrmions. Therefore, experimentally observing the coexisting phase and the topological transformation could be promising for developing skyrmion–antiskyrmion-based spintronics. However, such interactions and the detailed transformation mechanism remain unrevealed and unclear, respectively. Using Lorentz transmission electron microscopy experiments and micromagnetic simulations, we comprehensively study the properties in a coexisting phase of skyrmions and antiskyrmions in a Heusler material, Mn1.3Pt1.0Pd0.1Sn. Control of dipolar interaction (the sample thickness) allows us to realize a room-temperature coexisting phase. We find that the topological transformation occurs stochastically rather than deterministically, which can be explained by considering the magnetic point group and the direction of an in-plane magnetic field. We further observe isotropic long-range repulsive interaction between skyrmions and antiskyrmions in contrast to the conventional thought of the relative-position- and helicity-dependent short-range pairwise interactions, and deformation of skyrmions and antiskyrmions depending on the distance between them. Our simulations show that the deformation exerts significant influence on the magnetic energies and the energy landscape, contributing to the interaction. Our results provide insight into coexisting phases of skyrmions and antiskyrmions and a guide for developing skyrmion–antiskyrmion-based spintronics. [ABSTRACT FROM AUTHOR]

To investigate photoinduced phenomena in various materials and molecules, ultrashort pulsed x-ray and electron sources with high brightness and high repetition rates are required. The x-ray and electron's typical and de Broglie wavelengths are shorter than lattice constants of materials and molecules. Therefore, photoinduced structural dynamics on the femtosecond to picosecond timescales can be directly observed in a diffraction manner by using these pulses. This research created a tabletop ultrashort pulsed electron diffraction setup that used a femtosecond laser and electron pulse compression cavity that was directly synchronized to the microwave master oscillator (∼3 GHz). A compressed electron pulse with a 1 kHz repetition rate contained 228 000 electrons. The electron pulse duration was estimated to be less than 100 fs at the sample position by using photoinduced immediate lattice changes in an ultrathin silicon film (50 nm). The newly developed time-resolved electron diffraction setup has a pulse duration that is comparable to femtosecond laser pulse widths (35–100 fs). The pulse duration, in particular, fits within the timescale of photoinduced phenomena in quantum materials. Our developed ultrafast time-resolved electron diffraction setup with a sub-100 fs temporal resolution would be a powerful tool in material science with a combination of optical pump–probe, time-resolved photoemission spectroscopic, and pulsed x-ray measurements. [ABSTRACT FROM AUTHOR]

The aim of this article is to elucidate the short-circuit failure mechanism of SiC metal–oxide–semiconductor field-effect transistors that cause mechanical failure of the interlayer dielectric adjacent to the gate, to find the relationship between the short-circuit withstand capability and short-circuit failure time, and to classify failure modes by the short-circuit failure time. When the short-circuit failure time is shorter than the critical time, the stresses acting on the interlayer dielectric caused by the thermal expansion of the SiC die exceed the fracture stress limit of the oxide films. Therefore, cracks occur at the interlayer dielectric between the gate and the source. In this case, the short-circuit withstand capability can be predicted by thermal theory because the thermal expansion of the SiC die is determined by the temperature rise. However, when the short-circuit failure time is longer than the critical time, the stresses acting on the interlayer dielectric are less than the fracture stress limit of the oxide films. Thus, the failure mode changes to metallization short mode without causing interlayer dielectric cracks. Thermal stress simulations and experiments ascertain that the stress acting on the interlayer dielectric due to the thermal expansion of SiC varies with the short-circuit failure time, resulting in an altered failure mode. [ABSTRACT FROM AUTHOR]

The performance of a direct electron detector using silicon-on-insulator (SOI) technology in a low-voltage transmission electron microscope (LVTEM) is evaluated. The modulation transfer function and detective quantum efficiency of the detector are measured under backside illumination. The SOI-type detector is demonstrated to have high sensitivity and high efficiency for the direct detection of low-energy electrons. The detector is thus considered suitable for low-dose imaging in an LVTEM. [ABSTRACT FROM AUTHOR]

Th2 cytokine such as IL-4, IL -5 and IL-13 are important therapeutic targets for Th2-type chronic inflammation. Several biologics targeting Th2 cytokine and its receptors are effective in clinical practice; however, the development of small-molecule compounds that inhibit Th2 cytokine productions is awaited. We found that an inhibitor for pyruvate dehydrogenase kinase (PDHK) suppresses the differentiation of IL-5/IL-13-producing Th2 cells. The expression of the Th2-related transcriptional factors Pparγ was decreased by treatment with inhibitor, whereas Gata3, a master regulator of Th2 cell differentiation, remained unchanged. The oxygen consumption rate was unaffected, whereas the level of farnesylated proteins was decreased by the PDHK inhibitor. Furthermore, the inhibitors for farnesyltransferase and hydroxymethylglutaryl-CoA reductase showed an inhibitory effect similar to that of the PDHK inhibitor. These results suggest that the mevalonate biosynthesis and subsequent protein prenylation may be novel therapeutic target for Th2 cell-dependent immune dysregulation, such as in allergic diseases. • A PDHK inhibitor suppresses Th2 cells differentiation. • Protein prenylation in Th2 cells was suppressed by a PDHK inhibitor. • Farnesyltransferase inhibitor suppresses Th2 cells differentiation. • HMGCoA reductase inhibitor suppresses Th2 cell differentiation. [ABSTRACT FROM AUTHOR]

In order to produce a high brightness and high spin polarization electron beam, a pointlike emission mechanism is required for the photocathode of a GaAs polarized electron source. For this purpose, the laser spot size on the photocathode must be minimized, which is realized by changing the direction of the injection laser light from the front side to the back side of the photocathode. Based on this concept, a 20 kV gun was constructed with a transmission photocathode including an active layer of a GaAs–GaAsP superlattice layer. This system produces a laser spot diameter as small as 1.3 μm for 760–810 nm laser wavelength. The brightness of the polarized electron beam was ∼2.0×107 A cm-2 sr-1, which corresponds to a reduced brightness of ∼1.0×107 A m-2 sr-1 V-1. The peak polarization of 77% was achieved up to now. A charge density lifetime of 1.8×108 C cm-2 was observed for an extracted current of 3 μA. [ABSTRACT FROM AUTHOR]

Extremely low emittance electron beams are required for next generation accelerators. GaAs semiconductor photocathodes with negative electron affinity (NEA) surfaces have an intrinsic advantage for generating such low emittance beams and the thermal emittance as low as 0.1 π mm mrad is expected in ideal case. The thermal emittance of photoelectrons was measured for two different NEA photocathodes: a bulk-GaAs photocathode and a GaAs-GaAsP superlattice strained photocathode. The normalized root-mean-sqare emittances for the beam radius of 1.0 mm were as low as 0.20-0.29±0.02 and 0.15±0.02 π mm mrad, respectively. A comparison of these results shows that the superlattice photocathode minimizes the thermal emittance for photon excitation energies higher than the band gap energy. [ABSTRACT FROM AUTHOR]

The antitumor activity of activated CD8+ T cells in the tumor microenvironment seems to be limited due to their being metabolically unfit. This metabolic unfitness is closely associated with T‐cell exhaustion and impairment of memory formation, which are barriers to successful antitumor adoptive immunotherapy. We therefore assessed the role of glutamine metabolism in the antitumor activity of CD8+ T cells using a tumor‐inoculated mouse model. The adoptive transfer of tumor‐specific CD8+ T cells cultured under glutamine‐restricted (dGln) conditions or CD8+ T cells treated with specific inhibitors of glutamine metabolism efficiently eliminated tumors and led to better survival of tumor‐inoculated mice than with cells cultured under control (Ctrl) conditions. The decreased expression of PD‐1 and increased Ki67 positivity among tumor‐infiltrating CD8+ T cells cultured under dGln conditions suggested that the inhibition of glutamine metabolism prevents CD8+ T‐cell exhaustion in vivo. Furthermore, the transferred CD8+ T cells cultured under dGln conditions expanded more efficiently against secondary OVA stimulation than did CD8+ T cells under Ctrl conditions. We found that the expression of a pro‐survival factor and memory T cell‐related transcription factors was significantly higher in CD8+ T cells cultured under dGln conditions than in those cultured under Ctrl conditions. Given these findings, our study uncovered an important role of glutamine metabolism in the antitumor activity of CD8+ T cells. The novel adoptive transfer of tumor‐specific CD8+ T cells cultured in glutamine‐restricted conditions may be a promising approach to improve the efficacy of cell‐based adoptive immunotherapy. This manuscript uncovered an important role of glutamine metabolism in regulating antitumor activity of CD8+ T cells. Adoptive transfer of tumor‐specific CD8+ T cells cultured in glutamine‐restricted conditions improved the efficacy of CD8+ T cell‐based cancer adoptive immunotherapy. [ABSTRACT FROM AUTHOR]

Although Bach2 (broad complex-tramtrack-bric a brac and Cap’n’collar homology 2) plays an important role in regulating Th2 cell differentiation and type 2 immune responses, the underlying molecular mechanisms remain unclear. Our current studies demonstrate that Bach2 associates with Batf (basic leucine zipper transcription factor ATF-like) family transcription factors and binds to the regulatory regions of the Th2 cytokine gene loci. The Bach2–Batf complex antagonizes the recruitment of the interferon regulatory factor 4 (Irf4)-containing Batf complex to activator protein 1 (AP-1) motifs in the Th2 cytokine gene locus and suppresses Th2 cytokine production and/or Th2 cell differentiation. The deletion of Batf ameliorated the spontaneous development of type 2 airway inflammation that is found in mice with Bach2 deficiency specifically in T cells. Interestingly, Bach2 regulates Batf and Batf3 expression via two distinct pathways. First, the Bach2–Batf complex directly binds to the Batf and Batf3 gene loci and reduces transcription by interfering with the Batf–Irf4 complex. Second, Bach2 suppresses interleukin 4 (IL-4)-induced augmentation of Batf and Batf3 expression through the regulation of IL-4 production. These findings suggest that IL-4 and Batf family transcription factors form a positive feedback amplification loop to induce Th2 cell differentiation and that Bach2–Batf interactions block the formation of this amplification loop. Furthermore, we found that reductions in Bach2 confer an innate immunological function on CD4 T cells to induce antigen-independent cytokine production. Some Bach2 -deficient lung CD4 T cells showed characteristic features similar to pathogenic Th2 cells, including IL-33 receptor expression and IL-33-dependent Th2 cytokine production. These results suggest a critical role for Bach2 in regulating Th2 cell differentiation and the subsequent onset of chronic type 2 inflammation. [ABSTRACT FROM AUTHOR]

We developed an angle-resolved photoemission spectroscopy system for the analysis of conduction-band electrons. By forming a negative electron affinity surface on a semiconductor surface, electrons in conduction bands are emitted into a vacuum and measured by using an analyzer. This method enables us to determine the energy and momentum of the conduction electrons. Furthermore, it can be used to determine unoccupied conduction band structures. The main challenges of this method are that the energies of the emitted electrons are extremely low and the trajectories of the electrons change due to various influences. We overcame these problems by placing the shielding mesh close to the sample and parallel to the sample surface. The entire chambers, including the shielding mesh, were grounded, and a negative bias voltage was applied only to the sample. This configuration realizes the acceleration of electrons while preserving the momentum component parallel to the sample surface. Another problem is the establishment of a method for converting a detected angle into the corresponding wavevector. We focused on the emission angle of electrons emitted from a sample and their minimum energy and then established an analytical method for converting detected angles into corresponding wavevectors on the basis of the minimum energy. [ABSTRACT FROM AUTHOR]

Gfi1 plays an important role in the development and maintenance of many hematopoietic linage cells. However, the impact of Gfi1-deficiency on the iNKT cell differentiation remains unclear. We herein demonstrate a critical role of Gfi1 in regulating the development of iNKT cell subsets. In the thymus of T cell-specific Gfi1-deficient mice, iNKT cells normally developed up to stage 2, while the number of stage 3 NK1.1pos iNKT cells was significantly reduced. Furthermore, CD4pos iNKT cells were selectively reduced in the peripheral organs of T cell-specific Gfi1-deficient mice. The α-GalCer-dependent production of IFN-γand Th2 cytokines, but not IL-17A, was severely reduced in T cell-specific Gfi1-deficient mice. In addition, a reduction of the α-GalCer-induced anti-tumor activity was observed in Gfi1-deficient mice. These findings demonstrate the important role of Gfi1 in regulating the development and function of NKT1- and NKT2-type iNKT cell subsets. [ABSTRACT FROM AUTHOR]

A transcriptional repressor Gfi1 promotes T helper type 2 (Th2) cell development and inhibits Th17 and inducible regulatory T-cell differentiation. However, the role of Gfi1 in regulating Th1 cell differentiation and the Th1-type immune response remains to be investigated. We herein demonstrate that Gfi1 inhibits the induction of the Th1 programme in activated CD4 T cells. The activated Gfi1-deficient CD4 T cells spontaneously develop into Th1 cells in an interleukin-12- and interferon-c-independent manner. The increase of Th1-type immune responses was confirmed in vivo in Gfi1-deficient mice using a murine model of nickel allergy and delayed-type hypersensitivity (DTH). The expression levels of Th1-related transcription factors were found to increase in Gfi1-deficient activated CD4 T cells. Tbx21, Eomes and Runx2 were identified as possible direct targets of Gfi1. Gfi1 binds to the Tbx21, Eomes and Runx2 gene loci and reduces the histone H3K4 methylation levels in part by modulating Lsd1 recruitment. Together, these findings demonstrate a novel regulatory role of Gfi1 in the regulation of the Th1-type immune response. [ABSTRACT FROM AUTHOR]

Pulse-mode operation was realized in spin-polarized transmission electron microscopy (SP-TEM) using a laser-driven electron gun with a GaAs-GaAsP strained-layer-superlattice photocathode. TEM images were acquired with a pulsed electron beam with a 5-μs pulse duration. Phase locking of wobbling TEM images was demonstrated using a pulsed beam with a 1-kHz repetition frequency, which matched the image wobbling frequency. It was found that in composite images formed by superimposing 2 × 104 separate single-pulse exposures, the amount of image blurring due to wobbling was a linear function of the pulse duration. These results suggest the possibility of pump-probe measurements in SP-TEM using the pulsed electron beam as a probe, allowing nanometer-scale time-resolved spin mapping. [ABSTRACT FROM PUBLISHER]

High-brightness, high-current electron guns for energy recovery linac light sources and high repetition rate X-ray free-electron lasers require an exit beam energy of ≥500 keV to reduce space-charge induced emittance growth in the drift space from the gun exit to the following superconducting accelerator entrance. At the Japan Atomic Energy Agency, we have developed a DC photoemission gun employing a segmented insulator to mitigate the field emission problem, which is a major obstacle for operation of DC guns at ≥500 kV. The first demonstration of generating a 500-keV electron beam with currents up to 1.8 mA is presented. [ABSTRACT FROM AUTHOR]

IL-5 is a key cytokine that plays an important role in the development of pathological conditions in allergic inflammation. Identifying strategies to inhibit IL-5 production is important in order to establish new therapies for treating allergic inflammation. We found that SH-2251, a novel thioamide-related small compound, selectively inhibits the differentiation of IL-5-producing Th2 cells. SH-2251 inhibited the induction of active histone marks at the Il5 gene locus during Th2 cell differentiation. The recruitment of RNA polymerase II, and following expression of the Th2 cell-specific intergenic transcripts around the Il5 gene locus was also inhibited. Furthermore, Th2 cell-dependent airway inflammation in mice was suppressed by the oral administration of SH-2251. Gfi1, a transcriptional repressor, was identified as a downstream target molecule of SH-2251 using a DNA microarray analysis. The Gfi1 expression dramatically decreased in SH-2251-treated Th2 cells, and the SH-2251-mediated inhibition of IL-5-producing Th2 cell differentiation was restored by transduction of Gfi1. Therefore, our study unearthed SH-2251 as a novel therapeutic candidate for allergic inflammation that selectively inhibits active histone marks at the Il5 gene locus. [ABSTRACT FROM AUTHOR]

Sox4 is a transcription factor that regulates various developmental processes. Here we show that Sox4 was induced by TGF-? and negatively regulated the transcription factor GATA-3, the master regulator of function of T helper type 2 (TH2) cells, by two distinct mechanisms. First, Sox4 bound directly to GATA-3, preventing its binding to GATA-3 consensus DNA sequences. Second, Sox4 bound to the promoter region of the gene encoding interleukin 5 (IL-5), a TH2 cytokine, and prevented binding of GATA-3 to this promoter. TH2 cell-driven airway inflammation was modulated by alterations in Sox4 expression. Thus, Sox4 acted as a downstream target of TGF-? to inhibit GATA-3 function, TH2 differentiation and TH2 cell-mediated inflammation. [ABSTRACT FROM AUTHOR]

IL-4 plays an important role in the induction of Th2 and Th9 cells, as well as in the inhibition of Th1 cell generation. We show that a combination of IL-4 and TGF-β augments the development of Th1 cells that express CD103 (CD103+ Th1 cells) if IFN-γ is present. The T-box-containing transcription factor eomesodermin (Eomes) is preferentially expressed in CD103+ Th1 cells and is involved in IFN-γ production. The induction of T-bet during early T cell activation is essential for the formation of the active chromatin at both the Eomes and IFN-γ gene loci. TGF-β is required for the induction of Eomes and CD103, as well as the inhibition of Th2 cytokine expression. In addition, IL-4 induces Eomes transcription through activation of the Stat6-signaling pathway. IFN-γ-producing CD103+ Th1 cells are detected in the intraepithelial lymphocytes of normal mice, and their numbers significantly decrease in Tbet- and Staftî-deficient mice. To our knowledge, these results represent the first molecular mechanism of IL-4/TGF-β-dependent augmentation of Th1 cell generation and raise the possibility that IL-4 and TGF-β simultaneously enhance the Th1 cell-mediated immune responses under certain cytokine conditions. [ABSTRACT FROM AUTHOR]