49 research outputs found

    Magnetic properties and magnetic domain observation of ndfeb sintered magnets treated by grain boundary diffusion process with dyal co-sorption

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    Effective grain boundary diffusion (GBD) process with DyAl co-sorption is applied to enhance the coercivity of NdFeB sintered magnets. The coercivity of the magnet (HcJ = 1789 kA m⁻¹) subjected to the present GBD treatment was observed to be superior to that of the untreated magnet (HcJ = 1003 kA m⁻¹) and the conventional GBD magnet (HcJ = 1661 kA m⁻¹) treated with DyAl alloy. In the present GBD magnet, the DyAl co-sorption process facilitated Dy diffusion into the center region of the magnet (thickness: 3.5 mm), resulting in high coercivity. Further, magnetic domain observations were made using magnetic force microscopy (MFM) to observe the thermal demagnetization behavior of the present GBD magnet. The present GBD magnet suppressed the continuous domain reversal of adjacent grains; thus, the partially persistent single-domain structure remained, even at 453 K.M.Uenohara, H.Nishio, K.Toyoki, et al. Magnetic properties and magnetic domain observation of ndfeb sintered magnets treated by grain boundary diffusion process with dyal co-sorption. Materials Transactions 62, 1216 (2021); https://doi.org/10.2320/matertrans.MT-M2020389

    早期糖尿病性腎症での腎臓におけるα-Klotho 発現の低下とその尿中カルシウム排世に対する役割についての検討

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    Hypercalciuria is one of the early manifestations of diabetic nephropathy. We explored here the role of α-Klotho, a protein expressed predominantly in distal convoluted tubules that has a role in calcium reabsorption. We studied 31 patients with early diabetic nephropathy and compared them with 31 patients with IgA nephropathy and 7 with minimal change disease. Renal α-Klotho expression was significantly lower and urinary calcium excretion (UCa/UCr) significantly higher in diabetic nephropathy than in IgA nephropathy or minimal change disease. Multiple regression analyses indicated that α-Klotho mRNA was inversely correlated with calcium excretion. We next measured these parameters in a mouse model of streptozotocin (STZ)-induced diabetic nephropathy, characterized by glomerular hyperfiltration, as seen in early diabetic nephropathy. We also confirmed a reduction of renal α-Klotho mRNA down to almost 50% and enhanced calcium excretion in mice with STZ-induced diabetic nephropathy in comparison with nondiabetic mice. Hypercalciuria was exacerbated in heterozygous α-Klotho knockout mice in comparison with wild-type mice, each with STZ-induced diabetic nephropathy. Thus, α-Klotho expression was decreased in distal convoluted tubules in diabetic nephropathy in humans and mice. Renal loss of α-Klotho may affect urinary calcium excretion in early diabetic nephropathy.博士(医学)・乙第1293号・平成24年5月28日© 2012 International Society of Nephrolog

    Impact of hemodialysis on local vessel healing and thrombus formation after drug-eluting stent implantation

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    AbstractBackgroundAlthough hemodialysis (HD) is a suggested risk factor for stent thrombosis, its contribution to local vessel healing after drug-eluting stent (DES) implantation is unclear.MethodsA total of 121 patients (152 lesions treated with DES) who underwent 8-month follow-up coronary angiography with optical coherence tomography (OCT) were enrolled, and the findings were compared between patients with and without HD. To match baseline differences, mid-term OCT findings of 42 propensity score-matched lesions (21 non-HD vs. 21 HD) were compared. Effects of HD on the efficacy of antiplatelet therapy were also evaluated by VerifyNow assay (Accumetrics, San Diego, CA, USA).ResultsPatients with HD had a significantly higher rate of thrombus formation than those without (64% vs. 33%, p=0.007), although the baseline parameters and lesion characteristics differed between the groups. Multivariate logistic regression analysis revealed that HD was associated with an increased risk of thrombus formation (odds ratio 5.991, 95% confidence interval: 1.972–18.199, p=0.002). Even after propensity-matching for patient background and balancing of angiographic and OCT variables, the risk of thrombus formation remained significantly higher in HD patients. The P2Y12-reaction unit was significantly increased after HD (Pre HD: 211±75 vs. Post HD: 262±59, p=0.01), but patients without HD showed no increase during the same elapsed time (221±88 vs. 212±96, p=0.19).ConclusionsHD is a potential risk factor for subclinical thrombus attachment after DES therapy. Systemic problems, such as residual platelet reactivity, associated with HD as well as local vessel features in HD patients might contribute to the increased incidence of thrombus attachment and subsequent onset of thrombotic event after DES implantation

    慢性腎臓病では血中可溶型fms様チロシンキナーゼ-1産生の減少が動脈硬化症を悪化させる

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    Patients with chronic kidney disease (CKD) die of cardiovascular diseases for unknown reasons. Blood vessel formation in plaques and its relationship with plaque stability could be involved with signaling through the Flt-1 receptor and its ligands, vascular endothelial growth factor, and the closely related placental growth factor (PlGF). Flt-1 also exists as a circulating regulatory splice variant short-inhibitory form (sFlt-1) that serves as a decoy receptor, thereby inactivating PlGF. Heparin releases sFlt-1 by displacing the sFlt-1 heparin-binding site from heparin sulfate proteoglycans. Heparin could provide diagnostic inference or could also induce an antiangiogenic state. In the present study, postheparin sFlt-1 levels were lower in CKD patients than in control subjects. More importantly, sFlt-1 levels were inversely related to atherosclerosis in CKD patients, and this correlation was more robust after heparin injection, as verified by subsequent cardiovascular events. Knockout of apolipoprotein E (ApoE) and/or sFlt-1 showed that the absence of sFlt-1 worsened atherogenesis in ApoE-deficient mice. Thus, the relationship between atherosclerosis and PlGF signaling, as regulated by sFlt-1, underscores the underappreciated role of heparin in sFlt-1 release. These clinical and experimental data suggest that novel avenues into CKD-dependent atherosclerosis and its detection are warranted.博士(医学)・甲614号・平成26年3月17

    Geographic disparity of pathophysiological coronary artery disease characteristics: Insights from ASET trials

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    The geographical disparity in the pathophysiological pattern of coronary artery disease (CAD) among patients undergoing percutaneous coronary intervention (PCI) is unknown. To elucidate the geographical variance in the pathophysiological characteristics of CAD. Physiological indices derived from angiography-based fractional flow reserve pullbacks from patients with chronic coronary syndrome enrolled in the ASET Japan (n = 206) and ASET Brazil (n = 201) studies, which shared the same eligibility criteria, were analysed. The pathophysiological patterns of CAD were characterised using Murray law-based quantitative flow ratio (μQFR)-derived indices acquired from pre-PCI angiograms. The diffuseness of CAD was defined by the μQFR pullback pressure gradient index. Significant functional stenoses pre-PCI (μQFR ≤0.80) were more frequent in ASET Japan compared to ASET Brazil (89.9% vs. 67.5%, p < 0.001), as were rates of a post-PCI μQFR <0.91 (22.1% vs. 12.9%, p = 0.013). In the multivariable analysis, pre-procedural μQFR and diffuse disease were independent factors for predicting a post-PCI μQFR <0.91, which contributed to the different rates of post-PCI μQFR ≥0.91 between the studies. Among vessels with a post-PCI μQFR <0.91, a consistent diffuse pattern of CAD pre- and post-PCI occurred in 78.3% and 76.7% of patients in ASET Japan and Brazil, respectively; only 6.3% (Japan) and 10.0% (Brazil) of vessels had a major residual gradient. Independent risk factors for diffuse disease were diabetes mellitus in ASET Japan, and age and male gender in Brazil. There was geographic disparity in pre-procedural angiography-based pathophysiological characteristics. The combined pre-procedural physiological assessment of vessel μQFR and diffuseness of CAD may potentially identify patients who will benefit most from PCI. [Abstract copyright: Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.

    チョウコウネツ シゲンキン ユライ ノ タイネツセイ DNA リガーゼ ニ カンスル ケンキュウ

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    京都大学0048新制・課程博士博士(工学)甲第10229号工博第2292号新制||工||1278(附属図書館)UT51-2003-H650京都大学大学院工学研究科合成・生物化学専攻(主査)教授 今中 忠行, 教授 青山 安宏, 教授 木村 俊作学位規則第4条第1項該当Doctor of EngineeringKyoto UniversityDA
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