High-temperature thermoelectric properties of the double-perovskite ruthenium oxide (Sr1−x_{1-x}Lax_x)2_2ErRuO6_6

We have prepared polycrystalline samples of (Sr$_{1-x}$La$_x$)$_2$ErRuO$_6$ and (Sr$_{1-x}$La$_x$)$_2$YRuO$_6$, and have measured the resistivity, Seebeck coefficient, thermal conductivity, susceptibility and x-ray absorption in order to evaluate the electronic states and thermoelectric properties of the doped double-perovskite ruthenates. We have observed a large Seebeck coefficient of -160 $\mu$V/K and a low thermal conductivity of 7 mW/cmK for $x$=0.1 at 800 K in air. These two values are suitable for efficient oxide thermoelectrics, although the resistivity is still as high as 1 $\Omega$cm. From the susceptibility and x-ray absorption measurements, we find that the doped electrons exist as Ru$^{4+}$ in the low spin state. On the basis of the measured results, the electronic states and the conduction mechanism are discussed.Comment: 6 pages, 4 figures, J. Appl. Phys. (accepted

Loading orientation dependence of the formation behavior of deformation kink bands in the Mg-based long-period stacking ordered (LPSO) phase

The variation in the deformation behavior of a directionally solidified (DS) Mg-based long-period stacking ordered (LPSO)-phase crystal depending on the loading orientation was examined. The frequency of formation of the beak-like shape of the deformation band, which is known as one of the important deformation mechanisms in the LPSO phase, monotonically decreased as the inclination angle of the loading orientation with respect to the crystal growth direction in the DS crystal increased, and was accompanied by a decrease in the yield stress due to the activation of basal slip. Deformation bands formed along a direction approximately perpendicular to the grain boundary independent of the loading orientation. The crystal rotation axes selected in the deformation bands were perpendicular to [0001] in almost all grains, independent of the loading orientation. However, the rotation axes in the bands were not fixed but varied between h1010 - i and h1120 - i; this variation was correlated with the loading axis. These observed features strongly suggest that the deformation bands formed in the LPSO phase are predominantly deformation kink bands and that the formation mechanism itself does not vary with the loading orientation but instead its details. The selectivity of the crystal rotation axis in the kink band is strongly affected by the loading orientation.Hagihara K., Okamoto T., Ueyama R., et al. Loading orientation dependence of the formation behavior of deformation kink bands in the Mg-based long-period stacking ordered (LPSO) phase. Materials Transactions 61, 1821 (2020); https://doi.org/10.2320/matertrans.MT-MM2019001

Expression of cysLT1 and cysLT2 Receptor in Chronic Hyperplastic Eosinophilic Sinusitis

Elevated production of cysteinyl leukotrienes (cysLTs) from sinus tissues and abundant sinus eosinophils are characteristic features of chronic hyperplastic eosinophilic sinusitis (CHS). CysLTs exert their action through G-protein-coupled receptors named cysLTs receptor type I (cysLT1R) and type II (cysLT2R). These expressions of cysLT receptors in the sinus mucosa have yet to be clarified and the relationship between eosinophilia and the expression of these receptors remains obscure. We compared the expressions of cysLT1R and cysLT2R in the sinus mucosa in patients with CHS, non-eosinophilic chronic sinusitis (NECS), and control sinus tissues; and analyzed the correlation between the expression of CysLTRs and the presence of sinus eosinophils by immunohistochemistry and real-time PCR. A significantly higher percentage of eosinophils expressing cysLT2R protein was observed in patients with CHS compared with NECS and controls. In addition, cysLT2R mRNA expression in CHS was significantly higher than in NECS and controls. Furthermore, a positive correlation was observed between cysLT2R mRNA expression and the number of infiltrated eosinophils. In contrast, the cysLT1R mRNA expression did not differ significantly among these groups. The effect of cysLTs on sinus eosinophils may be mediated through the cysLT2R in patients with CHS. These results may suggest the therapeutic benefit of cysLT2R antagonists in CHS

Transcriptomic analysis reveals differences in the regulation of amino acid metabolism in asexual and sexual planarians

Abstract Many flatworms can alternate between asexual and sexual reproduction. This is a powerful reproductive strategy enabling them to benefit from the features of the two reproductive modes, namely, rapid multiplication and genetic shuffling. The two reproductive modes are enabled by the presence of pluripotent adult stem cells (neoblasts), by generating any type of tissue in the asexual mode, and producing and maintaining germ cells in the sexual mode. In the current study, RNA sequencing (RNA-seq) was used to compare the transcriptomes of two phenotypes of the planarian Dugesia ryukyuensis: an asexual OH strain and an experimentally sexualized OH strain. Pathway enrichment analysis revealed striking differences in amino acid metabolism in the two worm types. Further, the analysis identified serotonin as a new bioactive substance that induced the planarian ovary de novo in a postembryonic manner. These findings suggest that different metabolic states and physiological conditions evoked by sex-inducing substances likely modulate stem cell behavior, depending on their different function in the asexual and sexual reproductive modes. The combination of RNA-seq and a feeding assay in D. ryukyuensis is a powerful tool for studying the alternation of reproductive modes, disentangling the relationship between gene expression and chemical signaling molecules

Melting of excitonic insulator phase by an intense terahertz pulse in Ta2_2NiSe5_5

In this study, the optical response to a terahertz pulse was investigated in the transition metal chalcogenide Ta$_2$NiSe$_5$, a candidate excitonic insulator. First, by irradiating a terahertz pulse with a relatively weak electric field (0.3 MV/cm), the spectral changes in reflectivity near the absorption edge due to third-order optical nonlinearity were measured and the absorption peak characteristic of the excitonic phase just below the interband transition was identified. Next, by irradiating a strong terahertz pulse with a strong electric field of 1.65 MV/cm, the absorption of the excitonic phase was found to be reduced, and a Drude-like response appeared in the mid-infrared region. These responses can be interpreted as carrier generation by exciton dissociation induced by the electric field, resulting in the partial melting of the excitonic phase and metallization. The presence of a distinct threshold electric field for carrier generation indicates exciton dissociation via quantum-tunnelling processes. The spectral change due to metallization by the electric field is significantly different from that due to the strong optical excitation across the gap, which can be explained by the different melting mechanisms of the excitonic phase in the two types of excitations.Comment: 66 pages, 11 figures, 2 table

Effect of Ethylene Diurea on Oxygen-induced Ischemic Retinopathy in the Neonatal Rat

This study investigated the effect of N-[2- (2-oxo-1-imidazolidinyl) ethyl]-N-phenylurea (ethylene diurea, EDU) on oxygen-induced ischemic retinopathy (OIR) in a neonatal rat model. OIR was induced by maintaining daily cycles of 80% oxygen (20.5h), ambient air (0.5h), and a progressive return to 80% oxygen (3h) for 12 days (postnatal day: P12). The rats were treated intraperitoneally with EDU (30mg/kg body weight) or distilled water (DW) from P6 to P17. At P18, the percentage of avascular areas in the total retinal area (%AVA) was measured, and retinal neovascularization (NV) was scored in ADPase-stained retinas. Retinal superoxide dismutase (SOD) activity in the retina was also determined by a chemiluminescence method. The mean %AVA in the EDU-treated group (9.3 ± 1.7%, n = 16) was lower than in the DW group (18.2 ± 4.7%, n = 17). EDU did not significantly affect NV, but significantly increased SOD activity (1.36 ± 0.13 units/mg protein, n = 4) compared to DW treatment (1.04 ± 0.01 units/mg protein, n = 4, P = 0.032) at P18. These results suggest that EDU treatment decreased the %AVA, accompanied by an increase in normal retinal vascular growth and/or a decrease in vessel proliferation. The increased SOD activity observed in the present study is likely to involve the EDU-mediated effects