575 research outputs found

    Collision condition indicted by High Pressure Phases in a Chondrite.

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    第3回極域科学シンポジウム/第35回南極隕石シンポジウム 11月29日(木)、30日(金) 国立国語研究所 2階講

    Cathodoluminescence and Raman Spectroscopic Characterization of Experimentally Shocked Plagioclase

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    Cathodoluminescence (CL) spectrum of plagioclase shows four emission bands at around 350, 420, 570 and 750 nm, which can be assigned to Ce3+, Al[Single Bond]O−[Single Bond]Al or Ti4+, Mn2+ and Fe3+ centers, respectively. Their CL intensities decrease with an increase in experimentally shock pressure. The peak wavelength of the emission band related to Mn2+ shifts from 570 nm for unshocked plagioclase to 630 nm for plagioclase shocked above 20 GPa. The Raman spectrum of unshocked plagioclase has pronounced peaks at around 170, 280, 480 and 510 cm−1, whereas Raman intensities of all peaks decrease with an increase in shock pressure. This result suggests that shock pressure causes destruction of the framework structure in various extents depending on the pressure applied to plagioclase. This destruction is responsible for a decrease in CL intensity and a peak shift of yellow emission related to Mn2+. An emission band at around 380 nm in the UV-blue region is observed in only plagioclase shocked above 30 GPa, whereas it has not been recognized in the unshocked plagioclase. Raman spectroscopy reveals that shock pressure above 30 GPa converts plagioclase into maskelynite. It implies that an emission band at around 380 nm is regarded as a characteristic CL signal for maskelynite. CL images of plagioclase shocked above 30 GPa show a dark linear stripe pattern superimposed on bright background, suggesting planer deformation features (PDFs) observed under an optical microscope. Similar pattern can be identified in Raman spectral maps. CL and Raman spectroscopy can be expected as a useful tool to evaluate shock pressure induced on the plagioclase in terrestrial and meteoritic samples

    Diabetic Cardiovascular Disease Induced by Oxidative Stress.

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    Cardiovascular disease (CVD) is the leading cause of morbidity and mortality among patients with diabetes mellitus (DM). DM can lead to multiple cardiovascular complications, including coronary artery disease (CAD), cardiac hypertrophy, and heart failure (HF). HF represents one of the most common causes of death in patients with DM and results from DM-induced CAD and diabetic cardiomyopathy. Oxidative stress is closely associated with the pathogenesis of DM and results from overproduction of reactive oxygen species (ROS). ROS overproduction is associated with hyperglycemia and metabolic disorders, such as impaired antioxidant function in conjunction with impaired antioxidant activity. Long-term exposure to oxidative stress in DM induces chronic inflammation and fibrosis in a range of tissues, leading to formation and progression of disease states in these tissues. Indeed, markers for oxidative stress are overexpressed in patients with DM, suggesting that increased ROS may be primarily responsible for the development of diabetic complications. Therefore, an understanding of the pathophysiological mechanisms mediated by oxidative stress is crucial to the prevention and treatment of diabetes-induced CVD. The current review focuses on the relationship between diabetes-induced CVD and oxidative stress, while highlighting the latest insights into this relationship from findings on diabetic heart and vascular disease

    Luminescence Properties of Experimentally Grown Forsterite Chondrule: Implication for Astromineralogy.

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    第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月17日(木) 国立国語研究所 2階講

    Heme Oxygenase-1 Expression Affects Murine Abdominal Aortic Aneurysm Progression.

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    Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme degradation, is a cytoprotective enzyme upregulated in the vasculature by increased flow and inflammatory stimuli. Human genetic data suggest that a diminished HO-1 expression may predispose one to abdominal aortic aneurysm (AAA) development. In addition, heme is known to strongly induce HO-1 expression. Utilizing the porcine pancreatic elastase (PPE) model of AAA induction in HO-1 heterozygous (HO-1+/-, HO-1 Het) mice, we found that a deficiency in HO-1 leads to augmented AAA development. Peritoneal macrophages from HO-1+/- mice showed increased gene expression of pro-inflammatory cytokines, including MCP-1, TNF-alpha, IL-1-beta, and IL-6, but decreased expression of anti-inflammatory cytokines IL-10 and TGF-beta. Furthermore, treatment with heme returned AAA progression in HO-1 Het mice to a wild-type profile. Using a second murine AAA model (Ang II-ApoE-/-), we showed that low doses of the HMG-CoA reductase inhibitor rosuvastatin can induce HO-1 expression in aortic tissue and suppress AAA progression in the absence of lipid lowering. Our results support those studies that suggest that pleiotropic statin effects might be beneficial in AAA, possibly through the upregulation of HO-1. Specific targeted therapies designed to induce HO-1 could become an adjunctive therapeutic strategy for the prevention of AAA disease

    Integrable Impurity Model with Spin and Flavour: Model Inspired by Resonant Tunneling in Quantum Dot

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    We introduce an integrable impurity model in which both electrons and impurity have spin and flavour degrees of freedom. This model is a generalization of the multi-channel Kondo model and closely related with resonant tunneling through quantum dot. The Hamiltonian is exactly diagonalized by means of the Bethe ansatz.Comment: 1 reference is adde
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