250 research outputs found

    Acoustic black and white holes of potential flow in a tube

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    We propose a new simple model of acoustic black hole in a thin tube, where the difference in the gravitational potential is used to create a transonic flow. The main merit of our transonic flow model is that the Euler equations can be solved analytically. In fact, we can obtain an exact solution to the equation in terms of a height function in the monatomic case γ=5/3\gamma=5/3. For arbitrary γ\gamma, we find that it takes a simple form by the near-sonic approximation. Moreover, we obtain two analytic solutions describing a backward wave and a forward wave, from which we can confirm the existence of sonic horizons.Comment: 17 pages, 8 figure

    Fabrication of submicron La2x_{2-x}Srx_{x}CuO4_{4} intrinsic Josephson junction stacks

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    Intrinsic Josephson junction (IJJ) stacks of cuprate superconductors have potential to be implemented as intrinsic phase qubits working at relatively high temperatures. We report success in fabricating submicron La2x_{2-x}Srx_{x}CuO4_{4} (LSCO) IJJ stacks carved out of single crystals. We also show a new fabrication method in which argon ion etching is performed after focused ion beam etching. As a result, we obtained an LSCO IJJ stack in which resistive multi-branches appeared. It may be possible to control the number of stacked IJJs with an accuracy of a single IJJ by developing this method.Comment: 5 pages, 6 figure

    p59fyn is associated with the development of hepatic steatosis due to chronic ethanol consumption

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    p59fyn, a protein tyrosine kinase belonging to the src-family, is involved in the regulatory mechanism of acute response to ethanol in the central nervous system. A previous report showed an association between src-family kinase activity and fatty acid oxidation, and it also reported that hepatic free fatty acid levels were low in Fyn−/− mice. We examined, using Fyn−/− mice whether Fyn is also involved in fatty acid metabolism and the development of pathological changes in the liver in response to chronic ethanol consumption. C57BL/6J Fyn−/− and Fyn+/+ mice were fed for 8 weeks with either a liquid diet comprising ethanol or one in which the calories from ethanol were replaced with carbohydrates. Chronic ethanol consumption for 8 weeks resulted in remarkable hepatic steatosis in Fyn+/+ mice but not in Fyn−/− mice. Chronic ethanol consumption induced a significant decrease in hepatic FFA and triglyceride levels in Fyn−/− mice. Levels of interleukin-6, which is associated with the enhancement of fatty acid oxidation, was also increased significantly in the livers of ethanol-fed Fyn−/− mice. The results suggest that Fyn is involved in the enhancement of fatty acid oxidation and the development of hepatic steatosis caused by chronic ethanol consumption

    Jasmonate-dependent plant defense restricts thrips performance and preference

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    <p>Abstract</p> <p>Background</p> <p>The western flower thrips (<it>Frankliniella occidentalis </it>[Pergande]) is one of the most important insect herbivores of cultivated plants. However, no pesticide provides complete control of this species, and insecticide resistance has emerged around the world. We previously reported the important role of jasmonate (JA) in the plant's immediate response to thrips feeding by using an <it>Arabidopsis </it>leaf disc system. In this study, as the first step toward practical use of JA in thrips control, we analyzed the effect of JA-regulated <it>Arabidopsis </it>defense at the whole plant level on thrips behavior and life cycle at the population level over an extended period. We also studied the effectiveness of JA-regulated plant defense on thrips damage in Chinese cabbage (<it>Brassica rapa </it>subsp. <it>pekinensis</it>).</p> <p>Results</p> <p>Thrips oviposited more on <it>Arabidopsis </it>JA-insensitive <it>coi1-1 </it>mutants than on WT plants, and the population density of the following thrips generation increased on <it>coi1-1 </it>mutants. Moreover, thrips preferred <it>coi1-1 </it>mutants more than WT plants. Application of JA to WT plants before thrips attack decreased the thrips population. To analyze these important functions of JA in a brassica crop plant, we analyzed the expression of marker genes for JA response in <it>B. rapa</it>. Thrips feeding induced expression of these marker genes and significantly increased the JA content in <it>B. rapa</it>. Application of JA to <it>B. rapa </it>enhanced plant resistance to thrips, restricted oviposition, and reduced the population density of the following generation.</p> <p>Conclusion</p> <p>Our results indicate that the JA-regulated plant defense restricts thrips performance and preference, and plays an important role in the resistance of <it>Arabidopsis </it>and <it>B. rapa </it>to thrips damage.</p

    Development of Convolutional Neural Networks for an Electron-Tracking Compton Camera

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    Electron-tracking Compton camera, which is a complete Compton camera with tracking Compton scattering electron by a gas micro time projection chamber, is expected to open up MeV gamma-ray astronomy. The technical challenge for achieving several degrees of the point spread function is the precise determination of the electron-recoil direction and the scattering position from track images. We attempted to reconstruct these parameters using convolutional neural networks. Two network models were designed to predict the recoil direction and the scattering position. These models marked 41 ~degrees of the angular resolution and 2.1 ~mm of the position resolution for 75 ~keV electron simulation data in Argon-based gas at 2 ~atm pressure. In addition, the point spread function of ETCC was improved to 15 ~degrees from 22 ~degrees for experimental data of 662 ~keV gamma-ray source. These performances greatly surpassed that using the traditional analysis

    Plant viruses and viroids in Japan

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    An increasing number of plant viruses and viroids have been reported from all over the world due largely to metavirogenomics approaches with technological innovation. Herein, the official changes of virus taxonomy, including the establishment of megataxonomy and amendments of the codes of virus classification and nomenclature, recently made by the International Committee on Taxonomy of Viruses were summarized. The continued efforts of the plant virology community of Japan to index all plant viruses and viroids occurring in Japan, which represent 407 viruses, including 303 virus species and 104 unclassified viruses, and 25 viroids, including 20 species and 5 unclassified viroids, as of October 2021, were also introduced. These viruses and viroids are collectively classified into 81 genera within 26 families of 3 kingdoms (Shotokuvirae, Orthornavirae, Pararnavirae) across 2 realms (Monodnaviria and Riboviria). This review also overviewed how Japan’s plant virus/viroid studies have contributed to advance virus/viroid taxonomy

    Plasma Xanthine Oxidoreductase Activity Associated with Glycemic Control in Patients with Pre-Dialysis Chronic Kidney Disease

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    Introduction: Xanthine oxidoreductase (XOR) activity plays an important role as a pivotal source of reactive oxygen species, which is associated with cardiovascular disease (CVD) events. Patients with CKD have increased risk of CVD events. In the present study, factors associated with plasma XOR activity in pre-dialysis CKD patients were investigated. Methods: In this cross-sectional study, plasma XOR activity in 118 pre-dialysis CKD patients (age 68 [57–75] years; 64 males, 26 with diabetes mellitus [DM]) was determined using a newly established highly sensitive assay based on (13C2,15N2) xanthine and liquid chromatography/triple quadrupole mass spectrometry. Results: Plasma glucose, hemoglobin A1c, and estimated glomerular filtration (eGFR) were significantly and positively correlated with plasma logarithmically transformed XOR (ln-XOR) activity. In multiple regression analyses, eGFR and hemoglobin A1c or plasma glucose were significantly, independently, and positively associated with plasma ln-XOR activity after adjusting for several confounders. Plasma XOR activity was significantly higher in CKD patients with (n = 26) than in those without (n = 92) DM (62.7 [32.3–122] vs. 25.7 [13.4–45.8] pmol/h/mL, p &#x3c; 0.001). A total of 38 patients were taking uric acid-lowering drugs. Multiple regression analysis of CKD patients not administered uric acid-lowering drugs (n = 80) showed no significant association between eGFR and plasma ln-XOR activity. In contrast, association between glycemic control and plasma ln-XOR activity was significant even in CKD patients without uric acid-lowering drug treatment. Conclusions: These results indicate the importance of glycemic control in CKD patients in regard to decreased XOR, possibly leading to a decrease in CVD events

    ウメ PRUNUS MUME SIEB. ET ZUCC. カラ ブンリ サレタCUCUMBER MOSAIC VIRUSワSUBGROUP Iニ ゾクス ガ ケッセイ ガク テキ ニ クベツ サレル

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    和歌山県紀南地域のウメに発生するウメ葉縁えそ病の罹病株からCucumber mosaic virus(CMV)が分離された。この分離株はウメに単独ではほとんど病徴を生じないが,Prunus necrotic ringspot virus類似ウイルスとの重複感染によって葉縁えそ,黄斑,不稔などの病徴を示した。この分離株(CMV-Um)は,RNA3の塩基配列ではアミノ酸でsubgroupIの分離株(CMV-O, -Y)と94-95%の,またsubgroupII(CMV-m2)とは同様に80%の相同性を示しsubgroupIと考えられた。しかしながら血清学的には,間接ELISA, DAS-ELISAおよび寒天ゲル拡散法のいずれでも,一部にsubgroupI,IIと異なる特異な抗原決定基を持つことが認められ,RNAの塩基配列と血清反応による分類が異なった。Japanese apricot isolate of Cucumber mosaic virus (CMV-Um) was isolated from Japanese apricot (Prunus mume Sieb. et Zucc.) showing leaf margin necrosis and abortion syndrome, together with prunus necrotic ringspot like ilarvirus. Serotype of CMV-Um was shown as neither subg. I nor II by both agar gel double diffusion and ELISA tests. Nucleotide sequence in RNA3 coat protein (CP) coding region of CMV-Um was determined and compared with the previous reports of other CMV-RNA3. Sequence homologies of nucleotides and putative amino acids between Um and subg. I isolates showed 91-93% and 94-95%, respectively. On the other hand, homology between Um and subg. II isolates showed similarly 75-76% and 80%. Hydrophilicity analysis of amino acid sequence, at the regions of high average hydrophilicity of CMV-Um CP indicated 4 amino acids changes in both subgroups in common, suggesting a few amino acids changes caused variation of CMV serotype. In conclusion, CMV-Um belongs to subg. I in sequence but is different from subg. I and II in serotype
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