Low-Temperature X-ray Crystal Structure Analysis of the Cage-Structured Compounds MBe13 (M = La, Sm, and U)

The beryllides MBe13 (M = rare earths and actinides) crystallize in a NaZn13-type cubic structure, which can be categorized as a cage-structured compound. In this study, powder X-ray diffraction measurements have been performed on LaBe13, SmBe13, and UBe13 in the temperature range between 7 and 300 K in order to investigate their crystallographic characteristics systematically. They keep the NaZn13-type cubic structure down to the lowest temperature. We estimated their Debye temperature to be 600 - 750 K from analyses of the temperature dependence of a lattice parameter, being in good agreement with the values reported previously. Rietveld refinements on the obtained powder patterns revealed that the M atom in the 8a site is located in an almost ideal snub cube formed by 24 Be atoms in the 96i site, whose caged structure is unchanged even at the low temperatures. In addition, it is argued from the temperature variation of an isotropic mean-square displacement parameter that the MBe13 compounds commonly have a low-energy phonon mode, which can be described by a model assuming an Einstein oscillation of the M atom with a characteristic temperature of ~ 160 K.Comment: 8 pages with 6 figures and 2 table

L-Arginine treatment may prevent tubulointerstitial nephropathy caused by germanium dioxide

L-Arginine treatment may prevent tubulointerstitial nephropathy caused by germanium dioxide.BackgroundLong-term oral ingestion of germanium dioxide (GeO2) causes progressive renal failure derived from tubulointerstitial nephropathy in humans and animals. The characteristic of GeO2-induced nephropathy is the renal tissue injury persisting for a long time, even after cessation of GeO2 ingestion. However, a treatment that can suppress the long-lasting renal tissue injury has not yet been established.MethodsUsing the methods of immunohistochemistry and reverse transcription-polymerase chain reaction, we examined the expression of ED1-positive cells (macrophages/monocytes), transforming growth factor (TGF)-β1 mRNA and protein and collagen type IV mRNA and protein in the kidneys of rats with GeO2-induced nephropathy. Concomitantly, the effects of L-arginine treatment on their expression was explored in the kidneys of rats with GeO2-induced nephropathy.ResultsChronic administration of GeO2 caused tubulointerstitial nephropathy characterized by leukocyte invasion into the enlarged tubulointerstitial space in rats. The expression of ED1-positive cells, TGF-β1 protein and collagen type IV protein was markedly increased in the tubulointerstitium of the renal cortex from rats with GeO2-induced nephropathy. Similarly, TGF-β1 and collagen type IV mRNA were significantly enhanced in the renal cortex of rats with GeO2-induced nephropathy. A small number of tubulointerstitial cells expressing TGF-β1 protein were also observed in the renal cortex of rats with GeO2-induced nephropathy. However, L-arginine treatment led to a parallel decrease in the expression of ED1-positive cells, TGF-β1 mRNA and collagen type IV mRNA and protein in rats with GeO2-induced nephropathy.ConclusionsIn general, collagen synthesis is driven by TGF-β1 in the fibrotic process associated with a variety of renal disorders. TGF-β1 is secreted by TGF-β1 producing cells such as macrophages, fibroblasts and myofibroblasts. Thus, the present study indicates that the expression of collagen type IV may be mediated by TGF-β1 released from invading macrophages and, to a lesser extent, released from tubulointerstitial cells, presumably fibroblasts and/or myofibroblasts in GeO2-induced nephropathy. L-Arginine treatment inhibits collagen type IV synthesis possibly by suppressing macrophage invasion and the resultant TGF-β1 expression in this nephropathy. L-Arginine treatment may be beneficial in the prevention of tubulointerstitial fibrosis, which is considered to be the terminal stage of GeO2-induced nephropathy

Crystalline Electric Field and Kondo Effect in SmOs4Sb12

Our ultrasound results obtained in pulsed magnetic fields show that the filled-skutterudite compound SmOs$_4$Sb$_{12}$ has the $\Gamma_{67}$ quartet crystalline-electric-field ground state. This fact suggests that the multipolar degrees of freedom of the $\Gamma_{67}$ quartet play an important role in the unusual physical properties of this material. On the other hand, the elastic response below $\approx$ 20 T cannot be explained using the localized 4$f$-electron model, which does not take into account the Kondo effect or ferromagnetic ordering. The analysis result suggests the presence of a Kondo-like screened state at low magnetic fields and its suppression at high magnetic fields above 20 T even at low temperatures.Comment: 4 pages, 4 figure

Sets of RNA Repeated Tags and Hybridization-Sensitive Fluorescent Probes for Distinct Images of RNA in a Living Cell

BACKGROUND: Imaging the behavior of RNA in a living cell is a powerful means for understanding RNA functions and acquiring spatiotemporal information in a single cell. For more distinct RNA imaging in a living cell, a more effective chemical method to fluorescently label RNA is now required. In addition, development of the technology labeling with different colors for different RNA would make it easier to analyze plural RNA strands expressing in a cell. METHODOLOGY/PRINCIPAL FINDINGS: Tag technology for RNA imaging in a living cell has been developed based on the unique chemical functions of exciton-controlled hybridization-sensitive oligonucleotide (ECHO) probes. Repetitions of selected 18-nucleotide RNA tags were incorporated into the mRNA 3'-UTR. Pairs with complementary ECHO probes exhibited hybridization-sensitive fluorescence emission for the mRNA expressed in a living cell. The mRNA in a nucleus was detected clearly as fluorescent puncta, and the images of the expression of two mRNAs were obtained independently and simultaneously with two orthogonal tag-probe pairs. CONCLUSIONS/SIGNIFICANCE: A compact and repeated label has been developed for RNA imaging in a living cell, based on the photochemistry of ECHO probes. The pairs of an 18-nt RNA tag and the complementary ECHO probes are highly thermostable, sequence-specifically emissive, and orthogonal to each other. The nucleotide length necessary for one tag sequence is much shorter compared with conventional tag technologies, resulting in easy preparation of the tag sequences with a larger number of repeats for more distinct RNA imaging

Enhanced production of nitric oxide, reactive oxygen species, and pro-inflammatory cytokines in very long chain saturated fatty acid-accumulated macrophages

<p>Abstract</p> <p>Background</p> <p>Deterioration of peroxisomal β-oxidation activity causes an accumulation of very long chain saturated fatty acids (VLCSFA) in various organs. We have recently reported that the levels of VLCSFA in the plasma and/or membranes of blood cells were significantly higher in patients with metabolic syndrome and in patients with coronary artery disease than the controls. The aim of the present study is to investigate the effect of VLCSFA accumulation on inflammatory and oxidative responses in VLCSFA-accumulated macrophages derived from X-linked adrenoleukodystrophy (X-ALD) protein (ALDP)-deficient mice.</p> <p>Results</p> <p>Elevated levels of VLCSFA were confirmed in macrophages from ALDP-deficient mice. The levels of nitric oxide (NO) production stimulated by lipopolysaccharide (LPS) and interferon-γ (IFN-γ), intracellular reactive oxygen species (ROS), and pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interluekin-6 (IL-6), and interleukin-12p70 (IL-12p70), were significantly higher in macrophages from ALDP-deficient mice than in those from wild-type mice. The inducible NO synthase (iNOS) mRNA expression also showed an increase in macrophages from ALDP-deficient mice.</p> <p>Conclusion</p> <p>These results suggested that VLCSFA accumulation in macrophages may contribute to the pathogenesis of inflammatory diseases through the enhancement of inflammatory and oxidative responses.</p

Elastic Response in the Dilute non-Kramers System Y1−x_{1-x}Prx_xIr2_2Zn20_{20}

Ultrasonic investigations of the single-site quadrupolar Kondo effect in diluted Pr system Y$_{0.966}$Pr$_{0.034}$Ir$_2$Zn$_{20}$ are reported. The elastic constant $(C_{11}-C_{12})/2$ is measured down to ~40 mK using ultrasound for the dilute system Y$_{0.966}$Pr$_{0.034}$Ir$_2$Zn$_{20}$ and the pure compound YIr$_2$Zn$_{20}$. We found that the elastic constant $(C_{11}-C_{12})/2$ of the Pr-dilute system exhibits a logarithmic temperature dependence below $T_0$ ~0.3 K, where non-Fermi-liquid (NFL) behavior in the specific heat and electrical resistivity is observed. This logarithmic temperature variation manifested in the $\Gamma_3$-symmetry quadrupolar susceptibility is consistent with the theoretical prediction of the quadrupolar Kondo effect by D. L. Cox. On the other hand, the pure compound YIr$_2$Zn$_{20}$ without $4f$-electron contributions shows nearly no change in its elastic constants evidencing negligible phonon contributions. In addition, clear acoustic de Haas-van Alphen (dHvA) oscillations in the elastic constant were detected for both compounds on applying magnetic field. This is mainly interpreted as contribution from the Fermi surface of YIr$_2$Zn$_{20}$.Comment: 9 pages, 4 figures, Proceedings of J-Physics 2019 International Conferenc