Intersections of ultracold atomic polarons and nuclear clusters: How is a chart of nuclides modified in dilute neutron matter?

Neutron star observations, as well as experiments on neutron-rich nuclei, used to motivate one to look at degenerate nuclear matter from its extreme, namely, pure neutron matter. As an important next step, impurities and clusters in dilute neutron matter have attracted special attention. In this paper, we review in-medium properties of these objects on the basis of the physics of polarons, which have been recently realized in ultracold atomic experiments. We discuss how such atomic and nuclear systems are related to each other in terms of polarons. In addition to the interdisciplinary understanding of in-medium nuclear clusters, it is shown that the quasiparticle energy of a single proton in neutron matter is associated with the symmetry energy, implying a novel route toward the nuclear equation of state from the neutron-rich side.Comment: 28 pages, 2 figure

Discovery of chemosynthesis-based association on the Cretaceous basal leatherback sea turtle from Japan

We report a Late Cretaceous chemosynthetic community fueled by decomposing basal leatherback sea turtle on the ocean floor in the western Pacific. The fossil association representing this community has been recovered from the matrix of a concretion containing a single carapace of Mesodermochelys sp. from Late Cretaceous outer shelf to upper slope deposit of northern Hokkaido, Japan. The carapace displays boreholes most likely performed by boring bivalves, and is associated with molluscan shells, mainly Provanna cf. nakagawensis and Thyasira tanabei. Since this association is similar to fauna already known from Late Cretaceous hydrocarbon seeps, sunken wood, and plesiosaur-falls in Hokkaido, it is suggested that all types of chemosynthesis-based communities in the Late Cretaceous of western Pacific may have belonged to the same regional pool of animals and were not yet fully differentiated into three independent types of communities as it is known today. This finding also indicates that the sulfophilic stage of the vertebrate-fall communities was supported not only by plesiosaur carcasses, which were previously reported, but also by sea turtle carcasses. It highlights the possibility of surviving vertebrate-fall communities through the end-Cretaceous mass extinction event on carcasses of sea turtles which are the only large marine vertebrates surviving this event

Light Curves and Event Rates of Axion Instability Supernovae

It was recently proposed that exotic particles can trigger a new stellar instability which is analogous to the e-e+ pair instability if they are produced and reach equilibrium in the stellar plasma. In this study, we construct axion instability supernova (AISN) models caused by the new instability to predict their observational signatures. We focus on heavy axion-like particles (ALPs) with masses of ~400 keV--2 MeV and coupling with photons of g_{ag}~10^{-5} GeV^{-1}. It is found that the 56Ni mass and the explosion energy are significantly increased by ALPs for a fixed stellar mass. As a result, the peak times of the light curves of AISNe occur earlier than those of standard pair-instability supernovae by 10--20 days when the ALP mass is equal to the electron mass. Also, the event rate of AISNe is 1.7--2.6 times higher than that of pair-instability supernovae, depending on the high mass cutoff of the initial mass function.Comment: 9 pages, 6 figures, 1 table, submitted to Ap

スルフォラファンはNrf2 活性化作用を介し抗酸化ストレス作用、アセトアルデヒド代謝作用およびLPS/TLR4 シグナル経路を阻害することで四塩化炭素およびエタノール投与により誘発されるアルコール肝線維症を改善する

Alcoholic liver disease (ALD)-related fibrosis results from a variety of mechanisms including the accumulation of acetaldehyde, reactive oxygen species, and hepatic overload of endogenous lipopolysaccharide (LPS). Alcohol cessation is the therapeutic mainstay for patients with all stages of ALD, whereas pharmacological strategies for liver fibrosis have not been established. Sulforaphane, a phytochemical found in cruciferous vegetables, activates nuclear factor erythroid 2-related factor 2 (Nrf2) and exerts anticancer, antidiabetic, and antimicrobial effects; however, few studies investigated its efficacy in the development of ALD-related fibrosis. Herein, we investigated the effect of sulforaphane on acetaldehyde metabolism and liver fibrosis in HepaRG and LX-2 cells, human hepatoma and hepatic stellate cell lines, respectively, as well as in a mouse model of alcoholic liver fibrosis induced by ethanol plus carbon tetrachloride (EtOH/CCl₄). Sulforaphane treatment induced the activity of acetaldehyde-metabolizing mitochondrial aldehyde dehydrogenase in HepaRG cells and suppressed the acetaldehyde-induced proliferation and profibrogenic activity in LX-2 cells with upregulation of Nrf2-regulated antioxidant genes, including HMOX1, NQO1, and GSTM3. Moreover, sulforaphane attenuated the LPS/toll-like receptor 4-mediated sensitization to transforming growth factor-β with downregulation of NADPH oxidase 1 (NOX1) and NOX4. In EtOH/CCl₄-treated mice, oral sulforaphane administration augmented hepatic acetaldehyde metabolism. Additionally, sulforaphane significantly inhibited Kupffer cell infiltration and fibrosis, decreased fat accumulation and lipid peroxidation, and induced Nrf2-regulated antioxidant response genes in EtOH/CCl₄-treated mice. Furthermore, sulforaphane treatment blunted hepatic exposure of gut-derived LPS and suppressed hepatic toll-like receptor 4 signaling pathway. Taken together, these results suggest sulforaphane as a novel therapeutic strategy in ALD-related liver fibrosis.博士（医学）・甲第811号・令和4年3月15日© 2020 Elsevier Inc. All rights reserved