Chirality of magnons is an intrinsic degree of freedom that characterizes the handedness of spin precession around its equilibrium direction. This commentary summarizes recent progress on spin ...pumping by ferromagnetic resonance in magnetic heterostructures. In particular, the commentary highlights one fundamental issue in spin pumping: the chirality dependence of the spin current.
Spin fluctuation and transition have always been one of the central topics of magnetism and condensed matter science. Experimentally, the spin fluctuation is found transcribed onto scattering ...intensity in the neutron-scattering process, which is represented by dynamical magnetic susceptibility and maximized at phase transitions. Importantly, a neutron carries spin without electric charge, and therefore it can bring spin into a sample without being disturbed by electric energy. However, large facilities such as a nuclear reactor are necessary. Here we show that spin pumping, frequently used in nanoscale spintronic devices, provides a desktop microprobe for spin transition; spin current is a flux of spin without an electric charge and its transport reflects spin excitation. We demonstrate detection of antiferromagnetic transition in ultra-thin CoO films via frequency-dependent spin-current transmission measurements, which provides a versatile probe for phase transition in an electric manner in minute devices.
Background and aims
Mast cells are the major effector cells in allergic disorders and many other informatory disorders. The mechanism of mast cell stabilization is not fully understood. Cumulative ...reports indicate that vitamin D (VitD) contributes to the homeostasis in the body. This study tests a hypothesis that VitD is required in the maintenance of the stability of mast cells.
Methods
The stability of mast cell lines, HMC1 cells, RBL‐2H3 cells, p815 cells, and mouse bone marrow‐derived mast cells (BMMC) was tested in the presence or absence of VitD3.
Results
Mast cells activated automatically in a VitD‐deficient environment. Exposure to calcitriol in the culture increased the expression of VitD receptor (VDR) in mast cells. VDR formed complexes with Lyn in mast cells to inhibit the binding of Lyn to the β chain of FcεRI and MyD88, which decreased the phosphorylation of Syk, decreased the levels of MAPK and NF‐κB. VDR bound to the promoter of TNF‐α to decrease the acetylation of histone H3/H4, RNA polymerase II and OCT1 (a transcription factor of TNF‐α) at the promoter locus and repressed the expression of TNF‐α in mast cells.
Conclusions
The data demonstrate that VitD is required to maintain the stability of mast cells. The deficiency of VitD results in mast cell activation.
The origin of enhanced superconductivity over 50 K in the recently discovered FeSe monolayer films grown on SrTiO
(STO), as compared to 8 K in bulk FeSe, is intensely debated. As with the ...ferrochalcogenides A
Fe
Se
and potassium-doped FeSe, which also have a relatively high-superconducting critical temperature (T
), the Fermi surface (FS) of the FeSe/STO monolayer films is free of hole-like FS, suggesting that a Lifshitz transition by which these hole FSs vanish may help increasing T
. However, the fundamental reasons explaining this increase of T
remain unclear. Here we report a 15 K jump of T
accompanying a second Lifshitz transition characterized by the emergence of an electron pocket at the Brillouin zone centre, which is triggered by high-electron doping following in situ deposition of potassium on FeSe/STO monolayer films. Our results suggest that the pairing interactions are orbital dependent in generating enhanced superconductivity in FeSe.
Merons which are topologically equivalent to one-half of skyrmions can exist only in pairs or groups in two-dimensional (2D) ferromagnetic (FM) systems. The recent discovery of meron lattice in ...chiral magnet Co
Zn
Mn
raises the immediate challenging question that whether a single meron pair, which is the most fundamental topological structure in any 2D meron systems, can be created and stabilized in a continuous FM film? Utilizing winding number conservation, we develop a new method to create and stabilize a single pair of merons in a continuous Py film by local vortex imprinting from a Co disk. By observing the created meron pair directly within a magnetic field, we determine its topological structure unambiguously and explore the topological effect in its creation and annihilation processes. Our work opens a pathway towards developing and controlling topological structures in general magnetic systems without the restriction of perpendicular anisotropy and Dzyaloshinskii-Moriya interaction.
Background and Aims
Mast cell activation interferes with the effects of allergen‐specific immunotherapy (SIT). Galectin‐1 (Gal‐1) is capable of regulating immune cells’ functions. This study tests ...the hypothesis that administration of Gal‐1 promotes and prolongs the efficacy of SIT via suppressing mast cell activation.
Methods
An intestinal allergy mouse model was developed. The coadministration of SIT and Gal‐1 on suppression of the allergic responses, prevention of mast cell activation, and generation of antigen‐specific regulatory T cells (Treg) in the intestine was observed in sensitized mice.
Results
The coadministration of Gal‐1 and SIT markedly suppressed the allergic responses in the mouse intestine vs the use of either SIT alone or Gal‐1 alone. The Gal‐1 binds to the IgE/FcɛRI complexes on the surface of mast cells to prevent mast cell activation during SIT. Gal‐1 promoted the SIT‐generated allergen‐specific Tregs in the intestine of sensitized mice. Coadministration of Gal‐1 and SIT significantly enhanced the efficacy of immunotherapy in suppressing allergic responses in the intestine, which lasted for at least for 12 months.
Conclusions
Long‐term effects of specific immunotherapy on intestinal allergy can be achieved with Gal‐1/SIT therapy by inhibiting mast cell activation and facilitating Treg development.
Superconductivity Modulated by Quantum Size Effects Guo, Yang; Zhang, Yan-Feng; Bao, Xin-Yu ...
Science (American Association for the Advancement of Science),
12/2004, Letnik:
306, Številka:
5703
Journal Article
Recenzirano
We have fabricated ultrathin lead films on silicon substrates with atomic-scale control of the thickness over a macroscopic area. We observed oscillatory behavior of the superconducting transition ...temperature when the film thickness was increased by one atomic layer at a time. This oscillating behavior was shown to be a manifestation of the Fabry-Pérot interference modes of electron de Broglie waves (quantum well states) in the films, which modulate the electron density of states near the Fermi level and the electron-phonon coupling, which are the two factors that control superconductivity transitions. This result suggests the possibility of modifying superconductivity and other physical properties of a thin film by exploiting well-controlled and thickness-dependent quantum size effects.
Despite recent progress in spin-current research, the detection of spin current has mostly remained indirect. By synchronizing a microwave waveform with synchrotron x-ray pulses, we use the ...ferromagnetic resonance of the Py (Ni_{81}Fe_{19}) layer in a Py/Cu/Cu_{75}Mn_{25}/Cu/Co multilayer to pump a pure ac spin current into the Cu_{75}Mn_{25} and Co layers, and then directly probe the spin current within the Cu_{75}Mn_{25} layer and the spin dynamics of the Co layer by x-ray magnetic circular dichroism. This element-resolved pump-probe measurement unambiguously identifies the ac spin current in the Cu_{75}Mn_{25} layer.
Background
The overproduction of IgE plays a critical role in the pathogenesis of allergy; the mechanism is unclear. Histone‐acetyltransferase (HAT) activities are required in gene transcription of a ...large number of molecules in the immune system of the body.
Objectives
This study tests a hypothesis that HAT Tat‐interactive protein 60 (Tip60) plays an important role in the initiation of IgE‐mediated allergy.
Methods
The effects of Tip60 on regulating IgE expression were assessed with B cells. An intestinal allergy mouse model was developed to assess the role of Tip60 in the induction of IgE‐mediated allergic inflammation.
Results
High levels of Tip60 were observed in the peripheral B cells of patients with FA. Tat‐interactive protein 60 (Tip60) was required in the expression of IgE and IgG1 in B cells by inducing the chromatin remolding at the gene locus, in which histone acetylation, signal transducer and activator of transcription 6 (STAT6), and nuclear factor‐κB at the locus of Iε promoter were markedly increased. Blocking Tip60 significantly attenuated the allergic inflammation in the mouse intestinal mucosa.
Conclusions
Tat‐interactive protein 60 (Tip60) plays an important role in the induction of IgE in B cells. Blocking Tip60 inhibits the allergic inflammation in the intestine, suggesting Tip60 inhibitor may be a potential anti‐allergy drug.
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