Non-potential field formation in the X-shaped quadrupole magnetic field configuration

Some types of solar flares are observed in X-shaped quadrupolar field configuration. To understand the magnetic energy storage in such a region, we studied non-potential field formation in an X-shaped quadrupolar field region formed in the active region NOAA 11967, which produced three X-shaped M-class flares on February 2, 2014. Nonlinear force-free field modeling was applied to a time series of vector magnetic field maps from the Solar Optical Telescope on board Hinode and Helioseismic and Magnetic Imager on board Solar Dynamics Observatory. Our analysis of the temporal three-dimensional magnetic field evolution shows that the sufficient free energy had already been stored more than 10 hours before the occurrence of the first M-class flare and that the storage was observed in a localized region. In this localized region, quasi-separatrix layers (QSLs) started to develop gradually from 9 hours before the first M-class flare. One of the flare ribbons that appeared in the first M-class flare was co-spatial with the location of the QSLs, suggesting that the formation of the QSLs is important in the process of energy release. These QSLs do not appear in the potential field calculation, indicating that they were created by the non-potential field. The formation of the QSLs was associated with the transverse photospheric motion of the pre-emerged flux and the emergence of a new flux. This observation indicates that the occurrence of the flares requires the formation of QSLs in the non-potential field in which free magnetic energy is stored in advance.Comment: Accepted for publication in Ap

Unilateral radiculopathy away from the puncture site due to adhesive arachnoiditis after spinal anesthesia for an emergent cesarean delivery: a case report

[Background] Adhesive arachnoiditis has been described as a deteriorating neurological complication after neuraxial blockade; however, few pieces of literatures have reported minor cases that resemble peripheral neuropathy. [Case presentation] A 29-year-old nulliparous woman underwent an emergent cesarean delivery under spinal anesthesia at the second and third lumbar interspace (L2/3) without any specific concerns. Subsequently, she developed left L5 and sacral first (S1) radiculopathy that persisted for 2 months. Although the neurological findings more likely indicated peripheral neuropathy, magnetic resonance imaging revealed localized adhesive arachnoiditis at the left L5/S1 level. Her symptoms gradually improved and entirely disappeared within 2 months without any particular treatment. [Conclusion] The neurological symptoms that show a clear tendency to improve spontaneously do not always undergo a detailed workup. Therefore, such minor adhesive arachnoiditis might have occurred more than expected. Imaging such cases might cumulatively further the understanding of its etiology

A theoretical analysis on highly spin-polarized transport of iron nitride Fe_4N

In order to propose a ferromagnet exhibiting highly spin-polarized transport, we theoretically analyzed the spin polarization ratio of the conductivity of the bulk Fe$_4$N with a perovskite type structure, in which N is located at the body center position of fcc-Fe. The spin polarization ratio is defined by $P = (\sigma_\uparrow - \sigma_\downarrow) / (\sigma_\uparrow + \sigma_\downarrow )$, with $\sigma_{\uparrow(\downarrow)}$ being the conductivity at zero temperature of the up spin (down spin). The conductivity is obtained by using the Kubo formula and the Slater-Koster tight binding model, where parameters are determined from the least-square fitting of the dispersion curves by the tight binding model to those by the first principles calculation. In the vicinity of the Fermi energy, $|P|$ takes almost 1.0, indicating perfectly spin-polarized transport. In addition, by comparing Fe$_4$N to fcc-Fe (Fe$_4$N$_0$) in the ferromagnetic state with the equilibrium lattice constant of Fe$_4$N, it is shown that the non-magnetic atom N plays an important role in increasing $|P|$.Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev.

CRISPR/Cas9 unveils the dynamics of the endogenous µ‐opioid receptors on neuronal cells under continuous opioid stimulation

Long-term opioid use develops tolerance and attenuates analgesic effects. Upon activation, µ-opioid receptors (MOPs) are internalized and directed to either recycling or degradation pathway. Ligand stimulation also promotes de novo MOP synthesis. These processes collaboratively regulate MOP expression and play critical roles in tolerance development. However, there is limited understanding of how the endogenous MOP expression changes after prolonged opioid administration because previous analyses have focused on individual processes using overexpression systems, which ignored physiological regulation. Another fundamental problem is the unavailability of commercial antibodies to detect the low expression of endogenous MOP in neuronal systems. Here, we established a neuronal cell line to detect endogenous MOP with sufficient sensitivity using CRISPR/Cas9 technology. We incorporated the hemagglutinin sequence into the MOP gene of the SH-SY5Y cell. The genome-editing did not significantly impair MOP functions such as MOP internalization or the downstream signaling. The clone was differentiated into a state similar to the primary culture undergoing treatment with all-trans retinoic acid, followed by brain-derived neurotrophic factor. Upon continuous stimulation with MOP ligands, endogenous MOP constantly decreased up to 48 h. The expression level was maintained at a certain level following this period, depending on the ligand properties. DAMGO reduced MOP from the cell surface by about 70%, while morphine did so by 40%. Our results indicate that even a few days of opioid administration could significantly reduce the MOP expression level. Our cell line could be a potential tool to investigate the molecular mechanisms underlying the problems caused by long-term opioid use

Neural Network-Based Simulation Method to Examine Ion Behaviors Under Electric Fields: Application to Ion Migration in Amorphous Li3PO4

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Corporate Bond Markets of Korea, Malaysia and Thailand

Developing corporate bond markets is an important policy task for Asian countries. In Korea, there is much room for expansion of the market. In Malaysia, corporate bond issues have increased since the Asian crisis. In Thailand, the corporate bond market is not yet matured in comparison with Korea and Malaysia. Regarding corporate financing, the corporate bond market expanded in Malaysia and the issuance of bonds has gained the same importance as bank lending. On the other hand, in Korea and Thailand, the dependence of the financial system mainly on the banking sector has not changed. In the corporate bond markets of the three countries, issuing size should be enlarged and issuers should be more diversified. For that purpose, the various governments involved and the Asian Bond Markets Initiative must continue their efforts to develop the markets, while respecting market mechanisms and the situation of the financial system in each country