p38 Mitogen-activated Protein Kinase Regulates Oscillation of Chick Pineal Circadian Clock

Extracellular signal-regulated kinase (ERK) and p38 are members of the mitogen-activated protein kinase (MAPK) family, and in some cases these kinases serve for closely related cellular functions within a cell. In a wide range of animal clock structures, ERK plays an important role in the circadian time-keeping mechanism. Here we found that immunoreactivity to p38 protein was uniformly distributed among cells in the chick pineal gland. On the other hand, a constant level of activated p38 was detected over the day, predominantly in the follicular and parafollicular pinealocytes that are potential circadian clock-containing cells. Chronic application of SB203580, a selective and reversible inhibitor of p38, to the cultured chick pineal cells markedly lengthened the period of the circadian rhythm of the melatonin release (up to 28.7 h). Noticeably, despite no significant temporal change of activated p38 level, a 4-h pulse treatment with SB203580 delayed the phase of the rhythm only when delivered during the subjective day. These results indicate a time-of-day-specific role of continuously activated p38 in the period length regulation of the chick pineal clock and suggest temporally separated regulation of the clock by two MAPKs, nighttime-activated ERK and daytime-working p38

TA fluorescence detector calibration by UV LED with an unmanned aerial vehicle

ArticlePoS ICRC2017journal articl

General-relativistic neutrino-radiation magnetohydrodynamics simulation of seconds-long black hole-neutron star mergers: Dependence on initial magnetic field strength, configuration, and neutron-star equation of state

As a follow-up study of our previous work, numerical-relativity simulations for seconds-long black hole-neutron star mergers are performed for a variety of setups. Irrespective of the initial and symmetry conditions, we find qualitatively universal evolution processes: The dynamical mass ejection takes place together with a massive accretion disk formation after the neutron star is tidally disrupted; Subsequently, the magnetic field in the accretion disk is amplified by the magnetic winding, Kelvin-Helmholtz instability, and magnetorotational instability, which establish a turbulent state inducing the dynamo and angular momentum transport; The post-merger mass ejection by the effective viscous processes stemming from the magnetohydrodynamics turbulence sets in at $\sim300$-$500$ ms after the merger and continues for several hundred ms; A magnetosphere near the black-hole spin axis is developed and the collimated strong Poynting flux is generated with its lifetime of $\sim0.5$-$2$ s. We have newly found that the model of no equatorial-plane symmetry shows the reverse of the magnetic-field polarity in the magnetosphere, which is caused by the dynamo associated with the magnetorotational instability in the accretion disk. The model with initially toroidal fields shows the tilt of the disk and magnetosphere in the late post-merger stage because of the anisotropic post-merger mass ejection. These effects could terminate the strong Poynting-luminosity stage within the timescale of $\sim0.5$-$2$ s.Comment: 28 pages, 20 figures, and 2 tables. arXiv admin note: text overlap with arXiv:2111.0462

Development of a UAV-mounted Light Source for Fluorescence Detector Calibration of the Telescope Array Experiment

ArticleThe Physical Society of Japanjournal articl

Self-consistent picture of the mass ejection from a one second-long binary neutron star merger leaving a short-lived remnant in general-relativistic neutrino-radiation magnetohydrodynamic simulation

We perform a general-relativistic neutrino-radiation magnetohydrodynamic simulation of a one second-long binary neutron star merger on Japanese supercomputer Fugaku using about $72$ million CPU hours with $20,736$ CPUs. We consider an asymmetric binary neutron star merger with masses of $1.2$ and $1.5M_\odot$ and a `soft' equation of state SFHo. It results in a short-lived remnant with the lifetime of $\approx 0.017$\,s, and subsequent massive torus formation with the mass of $\approx 0.05M_\odot$ after the remnant collapses to a black hole. For the first time, we confirm that after the dynamical mass ejection, which drives the fast tail and mildly relativistic components, the post-merger mass ejection from the massive torus takes place due to the magnetorotational instability-driven turbulent viscosity and the two ejecta components are seen in the distributions of the electron fraction and velocity with distinct features.Comment: Accepted in PRL. 8 pages, 5 figure, Supplement Material is https://www2.yukawa.kyoto-u.ac.jp/~kenta.kiuchi/anime/FUGAKU/FUGAKU2022_Supplement_Material.pd

Actinide-boosting r Process in Black Hole-Neutron Star Merger Ejecta

We examine nucleosynthesis in the ejecta of black hole-neutron star mergers based on the results of self-consistent, long-term neutrino-radiation-magnetohydrodynamics simulations for the first time. We find that the combination of dynamical and post-merger ejecta reproduces a solar-like r-process pattern. Moreover, the enhancement level of actinides is highly sensitive to the distribution of both electron fraction and the velocity of the dynamical ejecta. Our result implies that the mean electron fraction of dynamical ejecta should be ~ 0.05-0.08 in order to reconcile the nucleosynthetic abundances with those in r-process-enhanced, actinide-boosted stars. This result provides an important constraint for nuclear equations of state.Comment: 5 pages, 4 figure

Optimization temperature sensitivity using the optically detected magnetic resonance spectrum of a nitrogen-vacancy center ensemble

Temperature sensing with nitrogen vacancy (NV) centers using quantum techniques is very promising and further development is expected. Recently, the optically detected magnetic resonance (ODMR) spectrum of a high-density ensemble of the NV centers was reproduced with noise parameters [inhomogeneous magnetic field, inhomogeneous strain (electric field) distribution, and homogeneous broadening] of the NV center ensemble. In this study, we use ODMR to estimate the noise parameters of the NV centers in several diamonds. These parameters strongly depend on the spin concentration. This knowledge is then applied to theoretically predict the temperature sensitivity. Using the diffraction-limited volume of 0.1 micron^3, which is the typical limit in confocal microscopy, the optimal sensitivity is estimated to be around 0.76 mK/Hz^(1/2) with an NV center concentration of 5.0e10^17/cm^3. This sensitivity is much higher than previously reported sensitivities, demonstrating the excellent potential of temperature sensing with NV centers.Comment: 17 pages, 4 figures, 1 tabl