A low-mass binary neutron star: long-term ejecta evolution and kilonovae with weak blue emission

We study the long-term evolution of ejecta formed in a binary neutron star (BNS) merger that results in a long-lived remnant NS by performing a hydrodynamics simulation with the outflow data of a numerical relativity simulation as the initial condition. At the homologously expanding phase, the total ejecta mass reaches $\approx0.1\,M_\odot$ with an average velocity of $\approx0.1\,c$ and lanthanide fraction of $\approx 0.005$. We further perform the radiative transfer simulation employing the obtained ejecta profile. We find that, contrary to a naive expectation from the large ejecta mass and low lanthanide fraction, the optical emission is not as bright as that in GW170817/AT2017gfo, while the infrared emission can be brighter. This light curve property is attributed to preferential diffusion of photons toward the equatorial direction due to the prolate ejecta morphology, large opacity contribution of Zr, Y, and lanthanides, and low specific heating rate of the ejecta. Our results suggest that these light curve features could be used as an indicator for the presence of a long-lived remnant NS. We also found that the bright optical emission broadly consistent with GW170817/AT2017gfo is realized for the case that the high-velocity ejecta components in the polar region are suppressed. These results suggest that the remnant in GW170817/AT2017gfo is unlikely to be a long-lived NS, but might have collapsed to a black hole within ${\cal O}(0.1)$ s

Electromagnetic counterparts of binary neutron star mergers leading to a strongly magnetized long-lived remnant neutron star

We explore the electromagnetic counterparts that will associate with binary neutron star mergers for the case that remnant massive neutron stars survive for $\gtrsim 0.5$ s after the merger. For this study, we employ the outflow profiles obtained by long-term general-relativistic neutrino-radiation magneto-hydrodynamics simulations with a mean field dynamo effect. We show that a synchrotron afterglow with high luminosity can be associated with the merger event if the magnetic fields of the remnant neutron stars are significantly amplified by the dynamo effect. We also perform a radiative transfer calculation for kilonovae and find that for the highly amplified magnetic field cases, the kilonovae can be bright in the early epoch ($t\leq 0.5\,{\rm d}$), while it shows rapid declining ($\lesssim 1\,{\rm d}$) emission and long-lasting ($\sim 10\,{\rm d}$) emission in the optical and near-infrared wavelength, respectively. All these features have not been found in GW170817, indicating that the merger remnant neutron star formed in GW170817 might have collapsed to a black hole within several hundreds ms or magnetic-field amplification might be a minor effect

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 magnetohydrodynamicsimulation of a one second-long binary neutron star merger on Japanesesupercomputer Fugaku using about $72$ million CPU hours with $20,736$ CPUs. Weconsider 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-livedremnant with the lifetime of $\approx 0.017$\,s, and subsequent massive torusformation with the mass of $\approx 0.05M_\odot$ after the remnant collapses toa black hole. For the first time, we confirm that after the dynamical massejection, which drives the fast tail and mildly relativistic components, thepost-merger mass ejection from the massive torus takes place due to themagnetorotational instability-driven turbulent viscosity and the two ejectacomponents are seen in the distributions of the electron fraction and velocitywith distinct features.<br

General-relativistic neutrino-radiation magnetohydrodynamics simulation of black hole-neutron star mergers for seconds

Seconds-long numerical-relativity simulations for black hole-neutron star mergers are performed for the first time to obtain a self-consistent picture of the merger and post-merger evolution processes. To investigate the case that tidal disruption takes place, we choose the initial mass of the black hole to be $5.4M_\odot$ or $8.1M_\odot$ with the dimensionless spin of 0.75. The neutron-star mass is fixed to be $1.35M_\odot$. We find that after the tidal disruption, dynamical mass ejection takes place spending $\lesssim 10\,{\rm ms}$ together with the formation of a massive accretion disk. Subsequently, the magnetic field in the disk is amplified by the magnetic winding and magnetorotational instability, establishing a turbulent state and inducing the angular momentum transport. The post-merger mass ejection by the magnetically-induced viscous effect sets in at $\sim 300$-$500\,{\rm ms}$ after the tidal disruption, at which the neutrino luminosity drops below $\sim 10^{51.5}\,{\rm erg/s}$, and continues for several hundreds ms. A magnetosphere near the rotational axis of the black hole is developed after the matter and magnetic flux fall into the black hole from the accretion disk, and high-intensity Poynting flux generation sets in at a few hundreds ms after the tidal disruption. The intensity of the Poynting flux becomes low after the significant post-merger mass ejection, because the opening angle of the magnetosphere increases. The lifetime for the stage with the strong Poynting flux is $1$-$2\,{\rm s}$, which agrees with the typical duration of short-hard gamma-ray bursts

Self-Assembly of 4-sided Fractals in the Two-handed Tile Assembly Model

We consider the self-assembly of fractals in one of the most well-studied models of tile based self-assembling systems known as the Two-handed Tile Assembly Model (2HAM). In particular, we focus our attention on a class of fractals called discrete self-similar fractals (a class of fractals that includes the discrete Sierpi\'nski carpet). We present a 2HAM system that finitely self-assembles the discrete Sierpi\'nski carpet with scale factor 1. Moreover, the 2HAM system that we give lends itself to being generalized and we describe how this system can be modified to obtain a 2HAM system that finitely self-assembles one of any fractal from an infinite set of fractals which we call 4-sided fractals. The 2HAM systems we give in this paper are the first examples of systems that finitely self-assemble discrete self-similar fractals at scale factor 1 in a purely growth model of self-assembly. Finally, we show that there exists a 3-sided fractal (which is not a tree fractal) that cannot be finitely self-assembled by any 2HAM system

In Vivo Imaging of HIF-Active Tumors by an Oxygen-Dependent Degradation Protein Probe with an Interchangeable Labeling System

Hypoxia-inducible factor (HIF) functions as a master transcriptional regulator for adaptation to hypoxia by inducing adaptive changes in gene expression for regulation of proliferation, angiogenesis, apoptosis and energy metabolism. Cancers with high expression of the alpha subunit of HIF (HIFα) are often malignant and treatment-resistant. Therefore, the development of a molecular probe that can detect HIF activity has great potential value for monitoring tumor hypoxia. HIF prolyl hydroxylases (HPHDs) act as oxygen sensors that regulate the fate of HIFα protein through its oxygen-dependent degradation (ODD) domain. We constructed a recombinant protein PTD-ODD-HaloTag (POH) that is under the same ODD regulation as HIFα and contains protein transduction domain (PTD) and an interchangeable labeling system. Administration of near-infrared fluorescently labeled POH (POH-N) to mouse models of cancers allowed successful monitoring of HIF-active regions. Immunohistochemical analysis for intratumoral localization of POH probe revealed its specificity to HIF-active cells. Furthermore, lack of the PTD domain or a point mutation in the ODD domain abrogated the specificity of POH-N to HIF-active cells. Overall results indicate that POH is a practical probe specific to HIF-active cell in cancers and suggest its large potential for imaging and targeting of HIF-related diseases

Study of double pion photoproduction on the deuteron

AbstractThe π+π− photoproductions on the proton and deuteron have been studied in a photon energy range of 0.8–1.1 GeV at the Laboratory of Nuclear Science, Tohoku University. Charged pions and protons were detected using Neutral Kaon Spectrometer. We obtained the cross sections for the p(γ,pπ+π−) and d(γ,pπ+π−)n. The quasi-free process with a neutron spectator was extracted by the neutron momentum cut of pn>0.3 GeV/c. The cross section for the Δ++Δ− production was deduced in the non-quasi-free process of the γd→pnπ+π−. It was 13.4±0.4 μb at Eγ=0.82 GeV

Protective effect of geranylgeranylacetone, an inducer of heat shock protein 70, against drug-induced lung injury/fibrosis in an animal model

<p>Abstract</p> <p>Background</p> <p>To determine whether oral administration of geranylgeranylacetone (GGA), a nontoxic anti-ulcer drug that is an inducer of heat shock protein (HSP) 70, protects against drug-induced lung injury/fibrosis <it>in vivo</it>.</p> <p>Methods</p> <p>We used a bleomycin (BLM)-induced lung fibrosis model in which mice were treated with oral 600 mg/kg of GGA before and after BLM administration. Inflammation and fibrosis were evaluated by histological scoring, hydroxyproline content in the lung and inflammatory cell count, and quantification by ELISA of macrophage inflammatory protein-2 (MIP-2) in bronchoalveolar lavage fluid. Apoptosis was evaluated by the TUNEL method. The induction of HSP70 in the lung was examined with western blot analysis and its localization was determined by immunohistochemistry.</p> <p>Results</p> <p>We confirmed the presence of inflammation and fibrosis in the BLM-induced lung injury model and induction of HSP70 by oral administration of GGA. GGA prevented apoptosis of cellular constituents of lung tissue, such as epithelial cells, most likely related to the <it>de novo </it>induction of HSP70 in the lungs. GGA-treated mice also showed less fibrosis of the lungs, associated with the findings of suppression of both production of MIP-2 and inflammatory cell accumulation in the injured lung, compared with vehicle-treated mice.</p> <p>Conclusion</p> <p>GGA had a protective effect on drug-induced lung injury/fibrosis. Disease-modifying antirheumatic drugs such as methotrexate, which are indispensable for the treatment of rheumatoid arthritis, often cause interstitial lung diseases, an adverse event that currently cannot be prevented. Clinical use of GGA for drug-induced pulmonary fibrosis might be considered in the future.</p

Elucidation of the liquid-liquid distribution behavior of ion associates of metal-halogeno complex anions with quaternary ammonium counter cations and its application to separation and analysis

第四級アンモニウムイオンを対イオンとする一価, 二価金属ハロゲノ錯陰イオンのイオン会合抽出挙動を把握し, 分離・分析的応用を図るために, 炭素数及び形状の異なる第四級アンモニウム陽イオンを用いて, 水-各種抽出溶媒 {1,2-ジクロロエタン, クロロホルム (CF), クロロベンゼン (Cl-B), ベンゼン (B), トルエン (T) 及び四塩化炭素 (CTC)} 系での抽出定数を求めた. 得られた抽出定数から次の知見を得た. (1) 配位子の抽出性に及ぼす影響 : 配位子がCl-, Br-, I-と変わるにつれ, この順に抽出性は良くなる. (2) 配位子数の影響 : 配位子数が多くなるに従い, 抽出性も良くなる. (3) 中心金属の影響 : 配位子数が同じ場合には, 抽出性はほぼ中心金属イオンの大きさの順となる. (4) 金属錯陰イオンの電荷の影響 : 一般に二価陰イオンよりも一価陰イオンのほうが抽出されやすい. (5) 対陽イオンのアルキル鎖のメチレン基の寄与 : メチレン基一つ当たり, 大体0.4～0.8の抽出定数 (log K(ex)) の増大となる. (6) 抽出溶媒の影響 : 抽出溶媒の抽出能は次の順となる : CTC<T<B<Cl-B<CF. (7) 金属ハロゲノ錯陰イオンの配位子の違いによる抽出定数の差 (Δlog K(ex)) は溶媒によらず, ほぼ一定である. これらの知見を基に, 金属ハロゲノ錯陰イオンと疎水性陽イオンとのイオン会合抽出を利用する幾つかの金属の分離・定量法を開発した.The distribution behavior of ion associates of both monovalent and divalent metal-halogeno complex anions with various quaternary ammonium cations between the aqueous phase and several organic phases {1,2-dichloroethane, chloroform (CF), chlorobenzene (Cl-B), benzene (B), toluene (T) and carbon tetrachloride (CTC)} was examined, and the extraction constants (log Kex) were determined. The larger is the size of the ligand (Cl-<Br-<I-) and the coordination number, the greater is the ion associability. For the same coordination number, in general, the larger is the size of the metal ion, the greater is the ion associability. In general, the extractability of monovalent metal-halogeno complex anions is larger than that of divalent metal-halogeno complex anions. A linear relationship was obtained between log Kex and the number of carbon atoms in quaternary ammonium ion, and the contribution of a methylene group to the extraction constant (Δlog K(ex)/-CH(2-)) was found to be about 0.4∼0.8. Among the ion associates examined, the order of the extractability of the extracting solvent was generally CTC<T<B<Cl-B<CF. Also, the order of the extractability of the ion associates for dihalogenocuprate (I), tetrahalogenoaurate (III) and tetrahalogenothallate (III) complex ions was as follows, respectively : CuCl(2)-<CuBr(2)-<CuI(2)- ; AuCl(4)-<AuBr(4)- ; TlCl(4)-<TlBr(4)-<TlI(4-). The values of Δlog K(ex) between the complex anions were almost equal, even though the extracting solvents were changed. From these results, several extraction-spectrophotometric methods for the determination of metal based on the formation of an ion associate of metal-halogeno complex anion with hydrophobic cations were developed