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The effects of uniaxial strain and hydrostatic pressure on Y0.98Ca0.02Ba2Cu4O8 [called Y0.98(Ca0.02)-124] are investigated via AC magnetic measurements under stress corresponding to a pressure of (at most) 20 GPa. Hydrostatic contraction results in the largest enhancement of the superconducting transition temperature (Tc), whose maximum is 99 K, which is slightly lower than the maximum Tc achieved in YBa2Cu4O8 (called Y-124). The Meissner signal disappears at a hydrostatic pressure of approximately 15 GPa. This pressure region representing the Meissner signal is reduced by the out-of-plane contraction (along the c-axis), whereas it is increased by the in-plane contraction (along the c-plane). In the case of Y-124, both uniaxial contractions result in the disappearance of the Meissner signal at approximately 10 GPa prior to reaching the overdoped region. However, by doping Ca into the Y-site, we could investigate uniaxial strain effects characteristic of the so-called 124 structure without causing the stress-induced structural transition through the underdoped, optimally doped, and overdoped regions. Except for the uniaxial contraction along the b-axis, the other contractions (i.e., hydrostatic contraction, and uniaxial contractions along the a- and the c-axes) exhibit consistent compression effects when Tc is normalized by the highest Tc and the stress is normalized by the stress realizing its highest Tc. [ABSTRACT FROM AUTHOR]

The nonlinear and linear magnetic responses to an ac magnetic field H are useful for the study of the magnetic dynamics of both magnetic domains and their constituent spins. In particular, the third-harmonic magnetic response M3ω reflects the dynamics of magnetic domains. Furthermore, by considering the ac magnetic response as a function of H, we can evaluate the degree of magnetic nonlinearity, which is closely related to M3ω. In this study, a series of approaches was used to examine the itinerant magnet MnP, in which both ferromagnetic and helical phases are present. On the basis of this investigation, we systematize the diagnostic approach to evaluating nonlinearity in magnetic responses. [ABSTRACT FROM AUTHOR]

In contrast to stage-specific transcription factors, the role of ubiquitous transcription factors in neuronal development remains a matter of scrutiny. Here, we demonstrated that a ubiquitous factor NF-Y is essential for neural progenitor maintenance during brain morphogenesis. Deletion of the NF-YA subunit in neural progenitors by using nestin-cre transgene in mice resulted in significant abnormalities in brain morphology, including a thinner cerebral cortex and loss of striatum during embryogenesis. Detailed analyses revealed a progressive decline in multiple neural progenitors in the cerebral cortex and ganglionic eminences, accompanied by induced apoptotic cell death and reduced cell proliferation. In neural progenitors, the NF-YA short isoform lacking exon 3 is dominant and co-expressed with cell cycle genes. ChIP-seq analysis from the cortex during early corticogenesis revealed preferential binding of NF-Y to the cell cycle genes, some of which were confirmed to be downregulated following NF-YA deletion. Notably, the NF-YA short isoform disappears and is replaced by its long isoform during neuronal differentiation. Forced expression of the NF-YA long isoform in neural progenitors resulted in a significant decline in neuronal count, possibly due to the suppression of cell proliferation. Collectively, we elucidated a critical role of the NF-YA short isoform in maintaining neural progenitors, possibly by regulating cell proliferation and apoptosis. Moreover, we identified an isoform switch in NF-YA within the neuronal lineage in vivo, which may explain the stage-specific role of NF-Y during neuronal development. [ABSTRACT FROM AUTHOR]