223 research outputs found

    Degeneration of the Julia set to singular loci of algebraic curves

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    We show that, when a non-integrable rational map changes to an integrable one continuously, a large part of the Julia set of the map approach indeterminate points (IDP) of the map along algebraic curves. We will see that the IDPs are singular loci of the curves.Comment: 12 pages, 5 figure

    Activation cross sections of \alpha-induced reactions on nat^{nat}Zn for Ge and Ga production

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    The production cross sections of 68,69^{68,69}Ge and 66,67^{66,67}Ga by \alpha-induced reactions on nat^{nat}Zn have been measured using the stacked-foil activation method and off-line \gamma-ray spectrometry from their threshold energies to 50.7 MeV. The derived cross sections were compared with the previous experimental data and the calculated values in the TENLD-2017 library. Our result shows a slightly larger amplitude than the previous data at the peak, though the peak energy is consistent with them.Comment: 12 pages, 6 figure

    Quantum Kelvin-Helmholtz instability in phase-separated two-component Bose-Einstein condensates

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    We theoretically study the Kelvin-Helmholtz instability in phase-separated two-component Bose-Einstein condensates using the Gross-Pitaevskii and Bogoliubov-de Gennes models. A flat interface between the two condensates is shown to deform into sawtooth or Stokes-like waves, leading to the formation of singly quantized vortices on the peaks and troughs of the waves. This scenario of interface instability in quantum fluids is quite different from that in classical fluids.Comment: 5 pages, 4 figure

    Crossover between Kelvin-Helmholtz and counter-superflow instabilities in two-component Bose-Einstein condensates

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    Dynamical instabilities at the interface between two Bose--Einstein condensates that are moving relative to each other are investigated using mean-field and Bogoliubov analyses. Kelvin--Helmholtz instability is dominant when the interface thickness is much smaller than the wavelength of the unstable interface mode, whereas the counter-superflow instability becomes dominant in the opposite case. These instabilities emerge not only in an immiscible system but also in a miscible system where an interface is produced by external potential. Dynamics caused by these instabilities are numerically demonstrated in rotating trapped condensates.Comment: 10 pages, 9 figure

    Radiological characteristics and diagnostic impact of duplicated right adrenal veins on adrenal venous sampling in primary aldosteronism

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    PURPOSEWe aimed to analyze the prevalence and radiological characteristics of duplicated right adrenal veins (DRAVs) and evaluate the diagnostic impact of adrenal venous sampling (AVS) in primary aldosteronism.METHODSDRAVs were retrospectively identified among patients who underwent segmental AVS between April 2017 and March 2020. DRAVs were defined as main or accessory according to the drainage area. The diameter, position, hormone levels, and treatment plan based on AVS were compared between main and accessory RAVs, using the Wilcoxon rank-sum test.RESULTSFourteen of 432 patients (3.2%) were diagnosed with DRAVs. On venography, the mean diameters of the main and accessory side were 3±0.63 mm and 2.1±0.41 mm, respectively, and were significantly different (p < 0.001). The mean relative position in craniocaudal direction of main and accessory veins from the adrenal caudal edge on computed tomography was 65.5%±16.0%, and 48.1%±16.8%, respectively, which was significantly different (p = 0.007). The left–right positions and hormone levels were not significantly different. Based on conventional AVS, the treatment plan between DRAVs was not changed in six of eight patients, but changed from surgery to medication in two patients with right aldosterone-producing adenoma (APA)/microadenoma based on segmental AVS findings.CONCLUSIONDRAVs, in which the main RAV was thicker and more cranially located than the accessory RAV were rare. Depending on blood sampled from either of DRAVs, the diagnosis made through conventional AVS might change treatment approach from surgery to medication, especially with right APA. Hence, their identification is important to make an accurate subtyping by AVS

    N-Acetylcysteine prevents amyloid-β secretion in neurons derived from human pluripotent stem cells with trisomy 21

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    ダウン症患者さん由来の神経細胞からのアミロイドβ分泌は抗酸化剤で抑止される. 京都大学プレスリリース. 2021-08-31.Stopping dementia in Down syndrome patients. 京都大学プレスリリース. 2021-08-31.Down syndrome (DS) is caused by the trisomy of chromosome 21. Among the many disabilities found in individuals with DS is an increased risk of early-onset Alzheimer's disease (AD). Although higher oxidative stress and an upregulation of amyloid β (Aβ) peptides from an extra copy of the APP gene are attributed to the AD susceptibility, the relationship between the two factors is unclear. To address this issue, we established an in vitro cellular model using neurons differentiated from DS patient-derived induced pluripotent stem cells (iPSCs) and isogenic euploid iPSCs. Neurons differentiated from DS patient-derived iPSCs secreted more Aβ compared to those differentiated from the euploid iPSCs. Treatment of the neurons with an antioxidant, N-acetylcysteine, significantly suppressed the Aβ secretion. These findings suggest that oxidative stress has an important role in controlling the Aβ level in neurons differentiated from DS patient-derived iPSCs and that N-acetylcysteine can be a potential therapeutic option to ameliorate the Aβ secretion

    Erythropoietin Receptor Signaling Mitigates Renal Dysfunction-Associated Heart Failure by Mechanisms Unrelated to Relief of Anemia

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    ObjectivesWe examined the effect of asialoerythropoietin (asialoEPO), a nonerythrogenic derivative of erythropoietin (EPO), on renal dysfunction-associated heart failure.BackgroundAlthough EPO is known to exert beneficial effects on cardiac function, the clinical benefits in patients with chronic kidney disease are controversial. It remains to be addressed whether previously reported outcomes were the result of relief of the anemia, adverse effects of EPO, or direct cardiovascular effects.MethodsMice underwent 5/6 nephrectomy to cause renal dysfunction. Eight weeks later, when renal dysfunction was established, anemia and cardiac dysfunction and remodeling were apparent. Mice were then assigned to receive saline (control), recombinant human erythropoietin (rhEPO) at 5,000 IU (714 pmol)/kg, or asialoEPO at 714 pmol/kg, twice/week for 4 weeks.ResultsAlthough only rhEPO relieved the nephrectomy-induced anemia, both rhEPO and asialoEPO significantly and similarly mitigated left ventricular dilation and dysfunction. The hearts of rhEPO- or asialoEPO-treated mice showed less hypertrophy, reflecting decreases in cardiomyocyte hypertrophy and degenerative subcellular changes, as well as significant attenuation of fibrosis, leukocyte infiltration, and oxidative deoxyribonucleic acid damage. These phenotypes were accompanied by restored expression of GATA-4, sarcomeric proteins, and vascular endothelial growth factor and decreased inflammatory cytokines and lipid peroxidation. Finally, myocardial activation was observed of extracellular signal-regulated protein kinase and signal transducer and activator of transcription pathways in the treated mice.ConclusionsEPO receptor signaling exerts direct cardioprotection in an animal model of renal dysfunction-associated heart failure, probably by mitigating degenerative, pro-fibrosis, inflammatory, and oxidative processes but not through relief of anemia
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